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 /*
  * net/tipc/socket.c: TIPC socket API
  *
  * Copyright (c) 2001-2007, 2012-2019, Ericsson AB
  * Copyright (c) 2004-2008, 2010-2013, Wind River Systems
  * Copyright (c) 2020-2021, Red Hat Inc
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the names of the copyright holders nor the names of its
  *    contributors may be used to endorse or promote products derived from
  *    this software without specific prior written permission.
  *
  * Alternatively, this software may be distributed under the terms of the
  * GNU General Public License ("GPL") version 2 as published by the Free
  * Software Foundation.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <linux/rhashtable.h>
 #include <linux/sched/signal.h>
 
 #include "core.h"
 #include "name_table.h"
 #include "node.h"
 #include "link.h"
 #include "name_distr.h"
 #include "socket.h"
 #include "bcast.h"
 #include "netlink.h"
 #include "group.h"
 #include "trace.h"
 
 #define NAGLE_START_INIT    4
 #define NAGLE_START_MAX     1024
 #define CONN_TIMEOUT_DEFAULT    8000    /* default connect timeout = 8s */
 #define CONN_PROBING_INTV   msecs_to_jiffies(3600000)  /* [ms] => 1 h */
 #define TIPC_MAX_PORT       0xffffffff
 #define TIPC_MIN_PORT       1
 #define TIPC_ACK_RATE       4       /* ACK at 1/4 of rcv window size */
 
 enum {
     TIPC_LISTEN = TCP_LISTEN,
     TIPC_ESTABLISHED = TCP_ESTABLISHED,
     TIPC_OPEN = TCP_CLOSE,
     TIPC_DISCONNECTING = TCP_CLOSE_WAIT,
     TIPC_CONNECTING = TCP_SYN_SENT,
 };
 
 struct sockaddr_pair {
     struct sockaddr_tipc sock;
     struct sockaddr_tipc member;
 };
 
 /**
  * struct tipc_sock - TIPC socket structure
  * @sk: socket - interacts with 'port' and with user via the socket API
  * @max_pkt: maximum packet size "hint" used when building messages sent by port
  * @maxnagle: maximum size of msg which can be subject to nagle
  * @portid: unique port identity in TIPC socket hash table
  * @phdr: preformatted message header used when sending messages
  * @cong_links: list of congested links
  * @publications: list of publications for port
  * @blocking_link: address of the congested link we are currently sleeping on
  * @pub_count: total # of publications port has made during its lifetime
  * @conn_timeout: the time we can wait for an unresponded setup request
  * @probe_unacked: probe has not received ack yet
  * @dupl_rcvcnt: number of bytes counted twice, in both backlog and rcv queue
  * @cong_link_cnt: number of congested links
  * @snt_unacked: # messages sent by socket, and not yet acked by peer
  * @snd_win: send window size
  * @peer_caps: peer capabilities mask
  * @rcv_unacked: # messages read by user, but not yet acked back to peer
  * @rcv_win: receive window size
  * @peer: 'connected' peer for dgram/rdm
  * @node: hash table node
  * @mc_method: cookie for use between socket and broadcast layer
  * @rcu: rcu struct for tipc_sock
  * @group: TIPC communications group
  * @oneway: message count in one direction (FIXME)
  * @nagle_start: current nagle value
  * @snd_backlog: send backlog count
  * @msg_acc: messages accepted; used in managing backlog and nagle
  * @pkt_cnt: TIPC socket packet count
  * @expect_ack: whether this TIPC socket is expecting an ack
  * @nodelay: setsockopt() TIPC_NODELAY setting
  * @group_is_open: TIPC socket group is fully open (FIXME)
  * @published: true if port has one or more associated names
  * @conn_addrtype: address type used when establishing connection
  */
 struct tipc_sock {
     struct sock sk;
     u32 max_pkt;
     u32 maxnagle;
     u32 portid;
     struct tipc_msg phdr;
     struct list_head cong_links;
     struct list_head publications;
     u32 pub_count;
     atomic_t dupl_rcvcnt;
     u16 conn_timeout;
     bool probe_unacked;
     u16 cong_link_cnt;
     u16 snt_unacked;
     u16 snd_win;
     u16 peer_caps;
     u16 rcv_unacked;
     u16 rcv_win;
     struct sockaddr_tipc peer;
     struct rhash_head node;
     struct tipc_mc_method mc_method;
     struct rcu_head rcu;
     struct tipc_group *group;
     u32 oneway;
     u32 nagle_start;
     u16 snd_backlog;
     u16 msg_acc;
     u16 pkt_cnt;
     bool expect_ack;
     bool nodelay;
     bool group_is_open;
     bool published;
     u8 conn_addrtype;
 };
 
 static int tipc_sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
 static void tipc_data_ready(struct sock *sk);
 static void tipc_write_space(struct sock *sk);
 static void tipc_sock_destruct(struct sock *sk);
 static int tipc_release(struct socket *sock);
 static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags,
                bool kern);
 static void tipc_sk_timeout(struct timer_list *t);
 static int tipc_sk_publish(struct tipc_sock *tsk, struct tipc_uaddr *ua);
 static int tipc_sk_withdraw(struct tipc_sock *tsk, struct tipc_uaddr *ua);
 static int tipc_sk_leave(struct tipc_sock *tsk);
 static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid);
 static int tipc_sk_insert(struct tipc_sock *tsk);
 static void tipc_sk_remove(struct tipc_sock *tsk);
 static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dsz);
 static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dsz);
 static void tipc_sk_push_backlog(struct tipc_sock *tsk, bool nagle_ack);
 static int tipc_wait_for_connect(struct socket *sock, long *timeo_p);
 
 static const struct proto_ops packet_ops;
 static const struct proto_ops stream_ops;
 static const struct proto_ops msg_ops;
 static struct proto tipc_proto;
 static const struct rhashtable_params tsk_rht_params;
 
 static u32 tsk_own_node(struct tipc_sock *tsk)
 {
     return msg_prevnode(&tsk->phdr);
 }
 
 static u32 tsk_peer_node(struct tipc_sock *tsk)
 {
     return msg_destnode(&tsk->phdr);
 }
 
 static u32 tsk_peer_port(struct tipc_sock *tsk)
 {
     return msg_destport(&tsk->phdr);
 }
 
 static  bool tsk_unreliable(struct tipc_sock *tsk)
 {
     return msg_src_droppable(&tsk->phdr) != 0;
 }
 
 static void tsk_set_unreliable(struct tipc_sock *tsk, bool unreliable)
 {
     msg_set_src_droppable(&tsk->phdr, unreliable ? 1 : 0);
 }
 
 static bool tsk_unreturnable(struct tipc_sock *tsk)
 {
     return msg_dest_droppable(&tsk->phdr) != 0;
 }
 
 static void tsk_set_unreturnable(struct tipc_sock *tsk, bool unreturnable)
 {
     msg_set_dest_droppable(&tsk->phdr, unreturnable ? 1 : 0);
 }
 
 static int tsk_importance(struct tipc_sock *tsk)
 {
     return msg_importance(&tsk->phdr);
 }
 
 static struct tipc_sock *tipc_sk(const struct sock *sk)
 {
     return container_of(sk, struct tipc_sock, sk);
 }
 
 int tsk_set_importance(struct sock *sk, int imp)
 {
     if (imp > TIPC_CRITICAL_IMPORTANCE)
         return -EINVAL;
     msg_set_importance(&tipc_sk(sk)->phdr, (u32)imp);
     return 0;
 }
 
 static bool tsk_conn_cong(struct tipc_sock *tsk)
 {
     return tsk->snt_unacked > tsk->snd_win;
 }
 
 static u16 tsk_blocks(int len)
 {
     return ((len / FLOWCTL_BLK_SZ) + 1);
 }
 
 /* tsk_blocks(): translate a buffer size in bytes to number of
  * advertisable blocks, taking into account the ratio truesize(len)/len
  * We can trust that this ratio is always < 4 for len >= FLOWCTL_BLK_SZ
  */
 static u16 tsk_adv_blocks(int len)
 {
     return len / FLOWCTL_BLK_SZ / 4;
 }
 
 /* tsk_inc(): increment counter for sent or received data
  * - If block based flow control is not supported by peer we
  *   fall back to message based ditto, incrementing the counter
  */
 static u16 tsk_inc(struct tipc_sock *tsk, int msglen)
 {
     if (likely(tsk->peer_caps & TIPC_BLOCK_FLOWCTL))
         return ((msglen / FLOWCTL_BLK_SZ) + 1);
     return 1;
 }
 
 /* tsk_set_nagle - enable/disable nagle property by manipulating maxnagle
  */
 static void tsk_set_nagle(struct tipc_sock *tsk)
 {
     struct sock *sk = &tsk->sk;
 
     tsk->maxnagle = 0;
     if (sk->sk_type != SOCK_STREAM)
         return;
     if (tsk->nodelay)
         return;
     if (!(tsk->peer_caps & TIPC_NAGLE))
         return;
     /* Limit node local buffer size to avoid receive queue overflow */
     if (tsk->max_pkt == MAX_MSG_SIZE)
         tsk->maxnagle = 1500;
     else
         tsk->maxnagle = tsk->max_pkt;
 }
 
 /**
  * tsk_advance_rx_queue - discard first buffer in socket receive queue
  * @sk: network socket
  *
  * Caller must hold socket lock
  */
 static void tsk_advance_rx_queue(struct sock *sk)
 {
     trace_tipc_sk_advance_rx(sk, NULL, TIPC_DUMP_SK_RCVQ, " ");
     kfree_skb(__skb_dequeue(&sk->sk_receive_queue));
 }
 
 /* tipc_sk_respond() : send response message back to sender
  */
 static void tipc_sk_respond(struct sock *sk, struct sk_buff *skb, int err)
 {
     u32 selector;
     u32 dnode;
     u32 onode = tipc_own_addr(sock_net(sk));
 
     if (!tipc_msg_reverse(onode, &skb, err))
         return;
 
     trace_tipc_sk_rej_msg(sk, skb, TIPC_DUMP_NONE, "@sk_respond!");
     dnode = msg_destnode(buf_msg(skb));
     selector = msg_origport(buf_msg(skb));
     tipc_node_xmit_skb(sock_net(sk), skb, dnode, selector);
 }
 
 /**
  * tsk_rej_rx_queue - reject all buffers in socket receive queue
  * @sk: network socket
  * @error: response error code
  *
  * Caller must hold socket lock
  */
 static void tsk_rej_rx_queue(struct sock *sk, int error)
 {
     struct sk_buff *skb;
 
     while ((skb = __skb_dequeue(&sk->sk_receive_queue)))
         tipc_sk_respond(sk, skb, error);
 }
 
 static bool tipc_sk_connected(struct sock *sk)
 {
     return sk->sk_state == TIPC_ESTABLISHED;
 }
 
 /* tipc_sk_type_connectionless - check if the socket is datagram socket
  * @sk: socket
  *
  * Returns true if connection less, false otherwise
  */
 static bool tipc_sk_type_connectionless(struct sock *sk)
 {
     return sk->sk_type == SOCK_RDM || sk->sk_type == SOCK_DGRAM;
 }
 
 /* tsk_peer_msg - verify if message was sent by connected port's peer
  *
  * Handles cases where the node's network address has changed from
  * the default of <0.0.0> to its configured setting.
  */
 static bool tsk_peer_msg(struct tipc_sock *tsk, struct tipc_msg *msg)
 {
     struct sock *sk = &tsk->sk;
     u32 self = tipc_own_addr(sock_net(sk));
     u32 peer_port = tsk_peer_port(tsk);
     u32 orig_node, peer_node;
 
     if (unlikely(!tipc_sk_connected(sk)))
         return false;
 
     if (unlikely(msg_origport(msg) != peer_port))
         return false;
 
     orig_node = msg_orignode(msg);
     peer_node = tsk_peer_node(tsk);
 
     if (likely(orig_node == peer_node))
         return true;
 
     if (!orig_node && peer_node == self)
         return true;
 
     if (!peer_node && orig_node == self)
         return true;
 
     return false;
 }
 
 /* tipc_set_sk_state - set the sk_state of the socket
  * @sk: socket
  *
  * Caller must hold socket lock
  *
  * Returns 0 on success, errno otherwise
  */
 static int tipc_set_sk_state(struct sock *sk, int state)
 {
     int oldsk_state = sk->sk_state;
     int res = -EINVAL;
 
     switch (state) {
     case TIPC_OPEN:
         res = 0;
         break;
     case TIPC_LISTEN:
     case TIPC_CONNECTING:
         if (oldsk_state == TIPC_OPEN)
             res = 0;
         break;
     case TIPC_ESTABLISHED:
         if (oldsk_state == TIPC_CONNECTING ||
             oldsk_state == TIPC_OPEN)
             res = 0;
         break;
     case TIPC_DISCONNECTING:
         if (oldsk_state == TIPC_CONNECTING ||
             oldsk_state == TIPC_ESTABLISHED)
             res = 0;
         break;
     }
 
     if (!res)
         sk->sk_state = state;
 
     return res;
 }
 
 static int tipc_sk_sock_err(struct socket *sock, long *timeout)
 {
     struct sock *sk = sock->sk;
     int err = sock_error(sk);
     int typ = sock->type;
 
     if (err)
         return err;
     if (typ == SOCK_STREAM || typ == SOCK_SEQPACKET) {
         if (sk->sk_state == TIPC_DISCONNECTING)
             return -EPIPE;
         else if (!tipc_sk_connected(sk))
             return -ENOTCONN;
     }
     if (!*timeout)
         return -EAGAIN;
     if (signal_pending(current))
         return sock_intr_errno(*timeout);
 
     return 0;
 }
 
 #define tipc_wait_for_cond(sock_, timeo_, condition_)                  \
 ({                                                                             \
     DEFINE_WAIT_FUNC(wait_, woken_wake_function);                          \
     struct sock *sk_;                              \
     int rc_;                                   \
                                            \
     while ((rc_ = !(condition_))) {                        \
         /* coupled with smp_wmb() in tipc_sk_proto_rcv() */            \
         smp_rmb();                                                     \
         sk_ = (sock_)->sk;                         \
         rc_ = tipc_sk_sock_err((sock_), timeo_);               \
         if (rc_)                               \
             break;                             \
         add_wait_queue(sk_sleep(sk_), &wait_);                         \
         release_sock(sk_);                         \
         *(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
         sched_annotate_sleep();                            \
         lock_sock(sk_);                            \
         remove_wait_queue(sk_sleep(sk_), &wait_);              \
     }                                      \
     rc_;                                       \
 })
 
 /**
  * tipc_sk_create - create a TIPC socket
  * @net: network namespace (must be default network)
  * @sock: pre-allocated socket structure
  * @protocol: protocol indicator (must be 0)
  * @kern: caused by kernel or by userspace?
  *
  * This routine creates additional data structures used by the TIPC socket,
  * initializes them, and links them together.
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_sk_create(struct net *net, struct socket *sock,
               int protocol, int kern)
 {
     const struct proto_ops *ops;
     struct sock *sk;
     struct tipc_sock *tsk;
     struct tipc_msg *msg;
 
     /* Validate arguments */
     if (unlikely(protocol != 0))
         return -EPROTONOSUPPORT;
 
     switch (sock->type) {
     case SOCK_STREAM:
         ops = &stream_ops;
         break;
     case SOCK_SEQPACKET:
         ops = &packet_ops;
         break;
     case SOCK_DGRAM:
     case SOCK_RDM:
         ops = &msg_ops;
         break;
     default:
         return -EPROTOTYPE;
     }
 
     /* Allocate socket's protocol area */
     sk = sk_alloc(net, AF_TIPC, GFP_KERNEL, &tipc_proto, kern);
     if (sk == NULL)
         return -ENOMEM;
 
     tsk = tipc_sk(sk);
     tsk->max_pkt = MAX_PKT_DEFAULT;
     tsk->maxnagle = 0;
     tsk->nagle_start = NAGLE_START_INIT;
     INIT_LIST_HEAD(&tsk->publications);
     INIT_LIST_HEAD(&tsk->cong_links);
     msg = &tsk->phdr;
 
     /* Finish initializing socket data structures */
     sock->ops = ops;
     sock_init_data(sock, sk);
     tipc_set_sk_state(sk, TIPC_OPEN);
     if (tipc_sk_insert(tsk)) {
         sk_free(sk);
         pr_warn("Socket create failed; port number exhausted\n");
         return -EINVAL;
     }
 
     /* Ensure tsk is visible before we read own_addr. */
     smp_mb();
 
     tipc_msg_init(tipc_own_addr(net), msg, TIPC_LOW_IMPORTANCE,
               TIPC_NAMED_MSG, NAMED_H_SIZE, 0);
 
     msg_set_origport(msg, tsk->portid);
     timer_setup(&sk->sk_timer, tipc_sk_timeout, 0);
     sk->sk_shutdown = 0;
     sk->sk_backlog_rcv = tipc_sk_backlog_rcv;
     sk->sk_rcvbuf = READ_ONCE(sysctl_tipc_rmem[1]);
     sk->sk_data_ready = tipc_data_ready;
     sk->sk_write_space = tipc_write_space;
     sk->sk_destruct = tipc_sock_destruct;
     tsk->conn_timeout = CONN_TIMEOUT_DEFAULT;
     tsk->group_is_open = true;
     atomic_set(&tsk->dupl_rcvcnt, 0);
 
     /* Start out with safe limits until we receive an advertised window */
     tsk->snd_win = tsk_adv_blocks(RCVBUF_MIN);
     tsk->rcv_win = tsk->snd_win;
 
     if (tipc_sk_type_connectionless(sk)) {
         tsk_set_unreturnable(tsk, true);
         if (sock->type == SOCK_DGRAM)
             tsk_set_unreliable(tsk, true);
     }
     __skb_queue_head_init(&tsk->mc_method.deferredq);
     trace_tipc_sk_create(sk, NULL, TIPC_DUMP_NONE, " ");
     return 0;
 }
 
 static void tipc_sk_callback(struct rcu_head *head)
 {
     struct tipc_sock *tsk = container_of(head, struct tipc_sock, rcu);
 
     sock_put(&tsk->sk);
 }
 
 /* Caller should hold socket lock for the socket. */
 static void __tipc_shutdown(struct socket *sock, int error)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct net *net = sock_net(sk);
     long timeout = msecs_to_jiffies(CONN_TIMEOUT_DEFAULT);
     u32 dnode = tsk_peer_node(tsk);
     struct sk_buff *skb;
 
     /* Avoid that hi-prio shutdown msgs bypass msgs in link wakeup queue */
     tipc_wait_for_cond(sock, &timeout, (!tsk->cong_link_cnt &&
                         !tsk_conn_cong(tsk)));
 
     /* Push out delayed messages if in Nagle mode */
     tipc_sk_push_backlog(tsk, false);
     /* Remove pending SYN */
     __skb_queue_purge(&sk->sk_write_queue);
 
     /* Remove partially received buffer if any */
     skb = skb_peek(&sk->sk_receive_queue);
     if (skb && TIPC_SKB_CB(skb)->bytes_read) {
         __skb_unlink(skb, &sk->sk_receive_queue);
         kfree_skb(skb);
     }
 
     /* Reject all unreceived messages if connectionless */
     if (tipc_sk_type_connectionless(sk)) {
         tsk_rej_rx_queue(sk, error);
         return;
     }
 
     switch (sk->sk_state) {
     case TIPC_CONNECTING:
     case TIPC_ESTABLISHED:
         tipc_set_sk_state(sk, TIPC_DISCONNECTING);
         tipc_node_remove_conn(net, dnode, tsk->portid);
         /* Send a FIN+/- to its peer */
         skb = __skb_dequeue(&sk->sk_receive_queue);
         if (skb) {
             __skb_queue_purge(&sk->sk_receive_queue);
             tipc_sk_respond(sk, skb, error);
             break;
         }
         skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE,
                       TIPC_CONN_MSG, SHORT_H_SIZE, 0, dnode,
                       tsk_own_node(tsk), tsk_peer_port(tsk),
                       tsk->portid, error);
         if (skb)
             tipc_node_xmit_skb(net, skb, dnode, tsk->portid);
         break;
     case TIPC_LISTEN:
         /* Reject all SYN messages */
         tsk_rej_rx_queue(sk, error);
         break;
     default:
         __skb_queue_purge(&sk->sk_receive_queue);
         break;
     }
 }
 
 /**
  * tipc_release - destroy a TIPC socket
  * @sock: socket to destroy
  *
  * This routine cleans up any messages that are still queued on the socket.
  * For DGRAM and RDM socket types, all queued messages are rejected.
  * For SEQPACKET and STREAM socket types, the first message is rejected
  * and any others are discarded.  (If the first message on a STREAM socket
  * is partially-read, it is discarded and the next one is rejected instead.)
  *
  * NOTE: Rejected messages are not necessarily returned to the sender!  They
  * are returned or discarded according to the "destination droppable" setting
  * specified for the message by the sender.
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_release(struct socket *sock)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk;
 
     /*
      * Exit if socket isn't fully initialized (occurs when a failed accept()
      * releases a pre-allocated child socket that was never used)
      */
     if (sk == NULL)
         return 0;
 
     tsk = tipc_sk(sk);
     lock_sock(sk);
 
     trace_tipc_sk_release(sk, NULL, TIPC_DUMP_ALL, " ");
     __tipc_shutdown(sock, TIPC_ERR_NO_PORT);
     sk->sk_shutdown = SHUTDOWN_MASK;
     tipc_sk_leave(tsk);
     tipc_sk_withdraw(tsk, NULL);
     __skb_queue_purge(&tsk->mc_method.deferredq);
     sk_stop_timer(sk, &sk->sk_timer);
     tipc_sk_remove(tsk);
 
     sock_orphan(sk);
     /* Reject any messages that accumulated in backlog queue */
     release_sock(sk);
     tipc_dest_list_purge(&tsk->cong_links);
     tsk->cong_link_cnt = 0;
     call_rcu(&tsk->rcu, tipc_sk_callback);
     sock->sk = NULL;
 
     return 0;
 }
 
 /**
  * __tipc_bind - associate or disassocate TIPC name(s) with a socket
  * @sock: socket structure
  * @skaddr: socket address describing name(s) and desired operation
  * @alen: size of socket address data structure
  *
  * Name and name sequence binding are indicated using a positive scope value;
  * a negative scope value unbinds the specified name.  Specifying no name
  * (i.e. a socket address length of 0) unbinds all names from the socket.
  *
  * Return: 0 on success, errno otherwise
  *
  * NOTE: This routine doesn't need to take the socket lock since it doesn't
  *       access any non-constant socket information.
  */
 static int __tipc_bind(struct socket *sock, struct sockaddr *skaddr, int alen)
 {
     struct tipc_uaddr *ua = (struct tipc_uaddr *)skaddr;
     struct tipc_sock *tsk = tipc_sk(sock->sk);
     bool unbind = false;
 
     if (unlikely(!alen))
         return tipc_sk_withdraw(tsk, NULL);
 
     if (ua->addrtype == TIPC_SERVICE_ADDR) {
         ua->addrtype = TIPC_SERVICE_RANGE;
         ua->sr.upper = ua->sr.lower;
     }
     if (ua->scope < 0) {
         unbind = true;
         ua->scope = -ua->scope;
     }
     /* Users may still use deprecated TIPC_ZONE_SCOPE */
     if (ua->scope != TIPC_NODE_SCOPE)
         ua->scope = TIPC_CLUSTER_SCOPE;
 
     if (tsk->group)
         return -EACCES;
 
     if (unbind)
         return tipc_sk_withdraw(tsk, ua);
     return tipc_sk_publish(tsk, ua);
 }
 
 int tipc_sk_bind(struct socket *sock, struct sockaddr *skaddr, int alen)
 {
     int res;
 
     lock_sock(sock->sk);
     res = __tipc_bind(sock, skaddr, alen);
     release_sock(sock->sk);
     return res;
 }
 
 static int tipc_bind(struct socket *sock, struct sockaddr *skaddr, int alen)
 {
     struct tipc_uaddr *ua = (struct tipc_uaddr *)skaddr;
     u32 atype = ua->addrtype;
 
     if (alen) {
         if (!tipc_uaddr_valid(ua, alen))
             return -EINVAL;
         if (atype == TIPC_SOCKET_ADDR)
             return -EAFNOSUPPORT;
         if (ua->sr.type < TIPC_RESERVED_TYPES) {
             pr_warn_once("Can't bind to reserved service type %u\n",
                      ua->sr.type);
             return -EACCES;
         }
     }
     return tipc_sk_bind(sock, skaddr, alen);
 }
 
 /**
  * tipc_getname - get port ID of socket or peer socket
  * @sock: socket structure
  * @uaddr: area for returned socket address
  * @peer: 0 = own ID, 1 = current peer ID, 2 = current/former peer ID
  *
  * Return: 0 on success, errno otherwise
  *
  * NOTE: This routine doesn't need to take the socket lock since it only
  *       accesses socket information that is unchanging (or which changes in
  *       a completely predictable manner).
  */
 static int tipc_getname(struct socket *sock, struct sockaddr *uaddr,
             int peer)
 {
     struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
 
     memset(addr, 0, sizeof(*addr));
     if (peer) {
         if ((!tipc_sk_connected(sk)) &&
             ((peer != 2) || (sk->sk_state != TIPC_DISCONNECTING)))
             return -ENOTCONN;
         addr->addr.id.ref = tsk_peer_port(tsk);
         addr->addr.id.node = tsk_peer_node(tsk);
     } else {
         addr->addr.id.ref = tsk->portid;
         addr->addr.id.node = tipc_own_addr(sock_net(sk));
     }
 
     addr->addrtype = TIPC_SOCKET_ADDR;
     addr->family = AF_TIPC;
     addr->scope = 0;
     addr->addr.name.domain = 0;
 
     return sizeof(*addr);
 }
 
 /**
  * tipc_poll - read and possibly block on pollmask
  * @file: file structure associated with the socket
  * @sock: socket for which to calculate the poll bits
  * @wait: ???
  *
  * Return: pollmask value
  *
  * COMMENTARY:
  * It appears that the usual socket locking mechanisms are not useful here
  * since the pollmask info is potentially out-of-date the moment this routine
  * exits.  TCP and other protocols seem to rely on higher level poll routines
  * to handle any preventable race conditions, so TIPC will do the same ...
  *
  * IMPORTANT: The fact that a read or write operation is indicated does NOT
  * imply that the operation will succeed, merely that it should be performed
  * and will not block.
  */
 static __poll_t tipc_poll(struct file *file, struct socket *sock,
                   poll_table *wait)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     __poll_t revents = 0;
 
     sock_poll_wait(file, sock, wait);
     trace_tipc_sk_poll(sk, NULL, TIPC_DUMP_ALL, " ");
 
     if (sk->sk_shutdown & RCV_SHUTDOWN)
         revents |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
     if (sk->sk_shutdown == SHUTDOWN_MASK)
         revents |= EPOLLHUP;
 
     switch (sk->sk_state) {
     case TIPC_ESTABLISHED:
         if (!tsk->cong_link_cnt && !tsk_conn_cong(tsk))
             revents |= EPOLLOUT;
         fallthrough;
     case TIPC_LISTEN:
     case TIPC_CONNECTING:
         if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
             revents |= EPOLLIN | EPOLLRDNORM;
         break;
     case TIPC_OPEN:
         if (tsk->group_is_open && !tsk->cong_link_cnt)
             revents |= EPOLLOUT;
         if (!tipc_sk_type_connectionless(sk))
             break;
         if (skb_queue_empty_lockless(&sk->sk_receive_queue))
             break;
         revents |= EPOLLIN | EPOLLRDNORM;
         break;
     case TIPC_DISCONNECTING:
         revents = EPOLLIN | EPOLLRDNORM | EPOLLHUP;
         break;
     }
     return revents;
 }
 
 /**
  * tipc_sendmcast - send multicast message
  * @sock: socket structure
  * @ua: destination address struct
  * @msg: message to send
  * @dlen: length of data to send
  * @timeout: timeout to wait for wakeup
  *
  * Called from function tipc_sendmsg(), which has done all sanity checks
  * Return: the number of bytes sent on success, or errno
  */
 static int tipc_sendmcast(struct  socket *sock, struct tipc_uaddr *ua,
               struct msghdr *msg, size_t dlen, long timeout)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_msg *hdr = &tsk->phdr;
     struct net *net = sock_net(sk);
     int mtu = tipc_bcast_get_mtu(net);
     struct sk_buff_head pkts;
     struct tipc_nlist dsts;
     int rc;
 
     if (tsk->group)
         return -EACCES;
 
     /* Block or return if any destination link is congested */
     rc = tipc_wait_for_cond(sock, &timeout, !tsk->cong_link_cnt);
     if (unlikely(rc))
         return rc;
 
     /* Lookup destination nodes */
     tipc_nlist_init(&dsts, tipc_own_addr(net));
     tipc_nametbl_lookup_mcast_nodes(net, ua, &dsts);
     if (!dsts.local && !dsts.remote)
         return -EHOSTUNREACH;
 
     /* Build message header */
     msg_set_type(hdr, TIPC_MCAST_MSG);
     msg_set_hdr_sz(hdr, MCAST_H_SIZE);
     msg_set_lookup_scope(hdr, TIPC_CLUSTER_SCOPE);
     msg_set_destport(hdr, 0);
     msg_set_destnode(hdr, 0);
     msg_set_nametype(hdr, ua->sr.type);
     msg_set_namelower(hdr, ua->sr.lower);
     msg_set_nameupper(hdr, ua->sr.upper);
 
     /* Build message as chain of buffers */
     __skb_queue_head_init(&pkts);
     rc = tipc_msg_build(hdr, msg, 0, dlen, mtu, &pkts);
 
     /* Send message if build was successful */
     if (unlikely(rc == dlen)) {
         trace_tipc_sk_sendmcast(sk, skb_peek(&pkts),
                     TIPC_DUMP_SK_SNDQ, " ");
         rc = tipc_mcast_xmit(net, &pkts, &tsk->mc_method, &dsts,
                      &tsk->cong_link_cnt);
     }
 
     tipc_nlist_purge(&dsts);
 
     return rc ? rc : dlen;
 }
 
 /**
  * tipc_send_group_msg - send a message to a member in the group
  * @net: network namespace
  * @tsk: tipc socket
  * @m: message to send
  * @mb: group member
  * @dnode: destination node
  * @dport: destination port
  * @dlen: total length of message data
  */
 static int tipc_send_group_msg(struct net *net, struct tipc_sock *tsk,
                    struct msghdr *m, struct tipc_member *mb,
                    u32 dnode, u32 dport, int dlen)
 {
     u16 bc_snd_nxt = tipc_group_bc_snd_nxt(tsk->group);
     struct tipc_mc_method *method = &tsk->mc_method;
     int blks = tsk_blocks(GROUP_H_SIZE + dlen);
     struct tipc_msg *hdr = &tsk->phdr;
     struct sk_buff_head pkts;
     int mtu, rc;
 
     /* Complete message header */
     msg_set_type(hdr, TIPC_GRP_UCAST_MSG);
     msg_set_hdr_sz(hdr, GROUP_H_SIZE);
     msg_set_destport(hdr, dport);
     msg_set_destnode(hdr, dnode);
     msg_set_grp_bc_seqno(hdr, bc_snd_nxt);
 
     /* Build message as chain of buffers */
     __skb_queue_head_init(&pkts);
     mtu = tipc_node_get_mtu(net, dnode, tsk->portid, false);
     rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
     if (unlikely(rc != dlen))
         return rc;
 
     /* Send message */
     rc = tipc_node_xmit(net, &pkts, dnode, tsk->portid);
     if (unlikely(rc == -ELINKCONG)) {
         tipc_dest_push(&tsk->cong_links, dnode, 0);
         tsk->cong_link_cnt++;
     }
 
     /* Update send window */
     tipc_group_update_member(mb, blks);
 
     /* A broadcast sent within next EXPIRE period must follow same path */
     method->rcast = true;
     method->mandatory = true;
     return dlen;
 }
 
 /**
  * tipc_send_group_unicast - send message to a member in the group
  * @sock: socket structure
  * @m: message to send
  * @dlen: total length of message data
  * @timeout: timeout to wait for wakeup
  *
  * Called from function tipc_sendmsg(), which has done all sanity checks
  * Return: the number of bytes sent on success, or errno
  */
 static int tipc_send_group_unicast(struct socket *sock, struct msghdr *m,
                    int dlen, long timeout)
 {
     struct sock *sk = sock->sk;
     struct tipc_uaddr *ua = (struct tipc_uaddr *)m->msg_name;
     int blks = tsk_blocks(GROUP_H_SIZE + dlen);
     struct tipc_sock *tsk = tipc_sk(sk);
     struct net *net = sock_net(sk);
     struct tipc_member *mb = NULL;
     u32 node, port;
     int rc;
 
     node = ua->sk.node;
     port = ua->sk.ref;
     if (!port && !node)
         return -EHOSTUNREACH;
 
     /* Block or return if destination link or member is congested */
     rc = tipc_wait_for_cond(sock, &timeout,
                 !tipc_dest_find(&tsk->cong_links, node, 0) &&
                 tsk->group &&
                 !tipc_group_cong(tsk->group, node, port, blks,
                          &mb));
     if (unlikely(rc))
         return rc;
 
     if (unlikely(!mb))
         return -EHOSTUNREACH;
 
     rc = tipc_send_group_msg(net, tsk, m, mb, node, port, dlen);
 
     return rc ? rc : dlen;
 }
 
 /**
  * tipc_send_group_anycast - send message to any member with given identity
  * @sock: socket structure
  * @m: message to send
  * @dlen: total length of message data
  * @timeout: timeout to wait for wakeup
  *
  * Called from function tipc_sendmsg(), which has done all sanity checks
  * Return: the number of bytes sent on success, or errno
  */
 static int tipc_send_group_anycast(struct socket *sock, struct msghdr *m,
                    int dlen, long timeout)
 {
     struct tipc_uaddr *ua = (struct tipc_uaddr *)m->msg_name;
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct list_head *cong_links = &tsk->cong_links;
     int blks = tsk_blocks(GROUP_H_SIZE + dlen);
     struct tipc_msg *hdr = &tsk->phdr;
     struct tipc_member *first = NULL;
     struct tipc_member *mbr = NULL;
     struct net *net = sock_net(sk);
     u32 node, port, exclude;
     struct list_head dsts;
     int lookups = 0;
     int dstcnt, rc;
     bool cong;
 
     INIT_LIST_HEAD(&dsts);
     ua->sa.type = msg_nametype(hdr);
     ua->scope = msg_lookup_scope(hdr);
 
     while (++lookups < 4) {
         exclude = tipc_group_exclude(tsk->group);
 
         first = NULL;
 
         /* Look for a non-congested destination member, if any */
         while (1) {
             if (!tipc_nametbl_lookup_group(net, ua, &dsts, &dstcnt,
                                exclude, false))
                 return -EHOSTUNREACH;
             tipc_dest_pop(&dsts, &node, &port);
             cong = tipc_group_cong(tsk->group, node, port, blks,
                            &mbr);
             if (!cong)
                 break;
             if (mbr == first)
                 break;
             if (!first)
                 first = mbr;
         }
 
         /* Start over if destination was not in member list */
         if (unlikely(!mbr))
             continue;
 
         if (likely(!cong && !tipc_dest_find(cong_links, node, 0)))
             break;
 
         /* Block or return if destination link or member is congested */
         rc = tipc_wait_for_cond(sock, &timeout,
                     !tipc_dest_find(cong_links, node, 0) &&
                     tsk->group &&
                     !tipc_group_cong(tsk->group, node, port,
                              blks, &mbr));
         if (unlikely(rc))
             return rc;
 
         /* Send, unless destination disappeared while waiting */
         if (likely(mbr))
             break;
     }
 
     if (unlikely(lookups >= 4))
         return -EHOSTUNREACH;
 
     rc = tipc_send_group_msg(net, tsk, m, mbr, node, port, dlen);
 
     return rc ? rc : dlen;
 }
 
 /**
  * tipc_send_group_bcast - send message to all members in communication group
  * @sock: socket structure
  * @m: message to send
  * @dlen: total length of message data
  * @timeout: timeout to wait for wakeup
  *
  * Called from function tipc_sendmsg(), which has done all sanity checks
  * Return: the number of bytes sent on success, or errno
  */
 static int tipc_send_group_bcast(struct socket *sock, struct msghdr *m,
                  int dlen, long timeout)
 {
     struct tipc_uaddr *ua = (struct tipc_uaddr *)m->msg_name;
     struct sock *sk = sock->sk;
     struct net *net = sock_net(sk);
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_nlist *dsts;
     struct tipc_mc_method *method = &tsk->mc_method;
     bool ack = method->mandatory && method->rcast;
     int blks = tsk_blocks(MCAST_H_SIZE + dlen);
     struct tipc_msg *hdr = &tsk->phdr;
     int mtu = tipc_bcast_get_mtu(net);
     struct sk_buff_head pkts;
     int rc = -EHOSTUNREACH;
 
     /* Block or return if any destination link or member is congested */
     rc = tipc_wait_for_cond(sock, &timeout,
                 !tsk->cong_link_cnt && tsk->group &&
                 !tipc_group_bc_cong(tsk->group, blks));
     if (unlikely(rc))
         return rc;
 
     dsts = tipc_group_dests(tsk->group);
     if (!dsts->local && !dsts->remote)
         return -EHOSTUNREACH;
 
     /* Complete message header */
     if (ua) {
         msg_set_type(hdr, TIPC_GRP_MCAST_MSG);
         msg_set_nameinst(hdr, ua->sa.instance);
     } else {
         msg_set_type(hdr, TIPC_GRP_BCAST_MSG);
         msg_set_nameinst(hdr, 0);
     }
     msg_set_hdr_sz(hdr, GROUP_H_SIZE);
     msg_set_destport(hdr, 0);
     msg_set_destnode(hdr, 0);
     msg_set_grp_bc_seqno(hdr, tipc_group_bc_snd_nxt(tsk->group));
 
     /* Avoid getting stuck with repeated forced replicasts */
     msg_set_grp_bc_ack_req(hdr, ack);
 
     /* Build message as chain of buffers */
     __skb_queue_head_init(&pkts);
     rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
     if (unlikely(rc != dlen))
         return rc;
 
     /* Send message */
     rc = tipc_mcast_xmit(net, &pkts, method, dsts, &tsk->cong_link_cnt);
     if (unlikely(rc))
         return rc;
 
     /* Update broadcast sequence number and send windows */
     tipc_group_update_bc_members(tsk->group, blks, ack);
 
     /* Broadcast link is now free to choose method for next broadcast */
     method->mandatory = false;
     method->expires = jiffies;
 
     return dlen;
 }
 
 /**
  * tipc_send_group_mcast - send message to all members with given identity
  * @sock: socket structure
  * @m: message to send
  * @dlen: total length of message data
  * @timeout: timeout to wait for wakeup
  *
  * Called from function tipc_sendmsg(), which has done all sanity checks
  * Return: the number of bytes sent on success, or errno
  */
 static int tipc_send_group_mcast(struct socket *sock, struct msghdr *m,
                  int dlen, long timeout)
 {
     struct tipc_uaddr *ua = (struct tipc_uaddr *)m->msg_name;
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_group *grp = tsk->group;
     struct tipc_msg *hdr = &tsk->phdr;
     struct net *net = sock_net(sk);
     struct list_head dsts;
     u32 dstcnt, exclude;
 
     INIT_LIST_HEAD(&dsts);
     ua->sa.type = msg_nametype(hdr);
     ua->scope = msg_lookup_scope(hdr);
     exclude = tipc_group_exclude(grp);
 
     if (!tipc_nametbl_lookup_group(net, ua, &dsts, &dstcnt, exclude, true))
         return -EHOSTUNREACH;
 
     if (dstcnt == 1) {
         tipc_dest_pop(&dsts, &ua->sk.node, &ua->sk.ref);
         return tipc_send_group_unicast(sock, m, dlen, timeout);
     }
 
     tipc_dest_list_purge(&dsts);
     return tipc_send_group_bcast(sock, m, dlen, timeout);
 }
 
 /**
  * tipc_sk_mcast_rcv - Deliver multicast messages to all destination sockets
  * @net: the associated network namespace
  * @arrvq: queue with arriving messages, to be cloned after destination lookup
  * @inputq: queue with cloned messages, delivered to socket after dest lookup
  *
  * Multi-threaded: parallel calls with reference to same queues may occur
  */
 void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
                struct sk_buff_head *inputq)
 {
     u32 self = tipc_own_addr(net);
     struct sk_buff *skb, *_skb;
     u32 portid, onode;
     struct sk_buff_head tmpq;
     struct list_head dports;
     struct tipc_msg *hdr;
     struct tipc_uaddr ua;
     int user, mtyp, hlen;
 
     __skb_queue_head_init(&tmpq);
     INIT_LIST_HEAD(&dports);
     ua.addrtype = TIPC_SERVICE_RANGE;
 
     /* tipc_skb_peek() increments the head skb's reference counter */
     skb = tipc_skb_peek(arrvq, &inputq->lock);
     for (; skb; skb = tipc_skb_peek(arrvq, &inputq->lock)) {
         hdr = buf_msg(skb);
         user = msg_user(hdr);
         mtyp = msg_type(hdr);
         hlen = skb_headroom(skb) + msg_hdr_sz(hdr);
         onode = msg_orignode(hdr);
         ua.sr.type = msg_nametype(hdr);
         ua.sr.lower = msg_namelower(hdr);
         ua.sr.upper = msg_nameupper(hdr);
         if (onode == self)
             ua.scope = TIPC_ANY_SCOPE;
         else
             ua.scope = TIPC_CLUSTER_SCOPE;
 
         if (mtyp == TIPC_GRP_UCAST_MSG || user == GROUP_PROTOCOL) {
             spin_lock_bh(&inputq->lock);
             if (skb_peek(arrvq) == skb) {
                 __skb_dequeue(arrvq);
                 __skb_queue_tail(inputq, skb);
             }
             kfree_skb(skb);
             spin_unlock_bh(&inputq->lock);
             continue;
         }
 
         /* Group messages require exact scope match */
         if (msg_in_group(hdr)) {
             ua.sr.lower = 0;
             ua.sr.upper = ~0;
             ua.scope = msg_lookup_scope(hdr);
         }
 
         /* Create destination port list: */
         tipc_nametbl_lookup_mcast_sockets(net, &ua, &dports);
 
         /* Clone message per destination */
         while (tipc_dest_pop(&dports, NULL, &portid)) {
             _skb = __pskb_copy(skb, hlen, GFP_ATOMIC);
             if (_skb) {
                 msg_set_destport(buf_msg(_skb), portid);
                 __skb_queue_tail(&tmpq, _skb);
                 continue;
             }
             pr_warn("Failed to clone mcast rcv buffer\n");
         }
         /* Append clones to inputq only if skb is still head of arrvq */
         spin_lock_bh(&inputq->lock);
         if (skb_peek(arrvq) == skb) {
             skb_queue_splice_tail_init(&tmpq, inputq);
             /* Decrement the skb's refcnt */
             kfree_skb(__skb_dequeue(arrvq));
         }
         spin_unlock_bh(&inputq->lock);
         __skb_queue_purge(&tmpq);
         kfree_skb(skb);
     }
     tipc_sk_rcv(net, inputq);
 }
 
 /* tipc_sk_push_backlog(): send accumulated buffers in socket write queue
  *                         when socket is in Nagle mode
  */
 static void tipc_sk_push_backlog(struct tipc_sock *tsk, bool nagle_ack)
 {
     struct sk_buff_head *txq = &tsk->sk.sk_write_queue;
     struct sk_buff *skb = skb_peek_tail(txq);
     struct net *net = sock_net(&tsk->sk);
     u32 dnode = tsk_peer_node(tsk);
     int rc;
 
     if (nagle_ack) {
         tsk->pkt_cnt += skb_queue_len(txq);
         if (!tsk->pkt_cnt || tsk->msg_acc / tsk->pkt_cnt < 2) {
             tsk->oneway = 0;
             if (tsk->nagle_start < NAGLE_START_MAX)
                 tsk->nagle_start *= 2;
             tsk->expect_ack = false;
             pr_debug("tsk %10u: bad nagle %u -> %u, next start %u!\n",
                  tsk->portid, tsk->msg_acc, tsk->pkt_cnt,
                  tsk->nagle_start);
         } else {
             tsk->nagle_start = NAGLE_START_INIT;
             if (skb) {
                 msg_set_ack_required(buf_msg(skb));
                 tsk->expect_ack = true;
             } else {
                 tsk->expect_ack = false;
             }
         }
         tsk->msg_acc = 0;
         tsk->pkt_cnt = 0;
     }
 
     if (!skb || tsk->cong_link_cnt)
         return;
 
     /* Do not send SYN again after congestion */
     if (msg_is_syn(buf_msg(skb)))
         return;
 
     if (tsk->msg_acc)
         tsk->pkt_cnt += skb_queue_len(txq);
     tsk->snt_unacked += tsk->snd_backlog;
     tsk->snd_backlog = 0;
     rc = tipc_node_xmit(net, txq, dnode, tsk->portid);
     if (rc == -ELINKCONG)
         tsk->cong_link_cnt = 1;
 }
 
 /**
  * tipc_sk_conn_proto_rcv - receive a connection mng protocol message
  * @tsk: receiving socket
  * @skb: pointer to message buffer.
  * @inputq: buffer list containing the buffers
  * @xmitq: output message area
  */
 static void tipc_sk_conn_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb,
                    struct sk_buff_head *inputq,
                    struct sk_buff_head *xmitq)
 {
     struct tipc_msg *hdr = buf_msg(skb);
     u32 onode = tsk_own_node(tsk);
     struct sock *sk = &tsk->sk;
     int mtyp = msg_type(hdr);
     bool was_cong;
 
     /* Ignore if connection cannot be validated: */
     if (!tsk_peer_msg(tsk, hdr)) {
         trace_tipc_sk_drop_msg(sk, skb, TIPC_DUMP_NONE, "@proto_rcv!");
         goto exit;
     }
 
     if (unlikely(msg_errcode(hdr))) {
         tipc_set_sk_state(sk, TIPC_DISCONNECTING);
         tipc_node_remove_conn(sock_net(sk), tsk_peer_node(tsk),
                       tsk_peer_port(tsk));
         sk->sk_state_change(sk);
 
         /* State change is ignored if socket already awake,
          * - convert msg to abort msg and add to inqueue
          */
         msg_set_user(hdr, TIPC_CRITICAL_IMPORTANCE);
         msg_set_type(hdr, TIPC_CONN_MSG);
         msg_set_size(hdr, BASIC_H_SIZE);
         msg_set_hdr_sz(hdr, BASIC_H_SIZE);
         __skb_queue_tail(inputq, skb);
         return;
     }
 
     tsk->probe_unacked = false;
 
     if (mtyp == CONN_PROBE) {
         msg_set_type(hdr, CONN_PROBE_REPLY);
         if (tipc_msg_reverse(onode, &skb, TIPC_OK))
             __skb_queue_tail(xmitq, skb);
         return;
     } else if (mtyp == CONN_ACK) {
         was_cong = tsk_conn_cong(tsk);
         tipc_sk_push_backlog(tsk, msg_nagle_ack(hdr));
         tsk->snt_unacked -= msg_conn_ack(hdr);
         if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)
             tsk->snd_win = msg_adv_win(hdr);
         if (was_cong && !tsk_conn_cong(tsk))
             sk->sk_write_space(sk);
     } else if (mtyp != CONN_PROBE_REPLY) {
         pr_warn("Received unknown CONN_PROTO msg\n");
     }
 exit:
     kfree_skb(skb);
 }
 
 /**
  * tipc_sendmsg - send message in connectionless manner
  * @sock: socket structure
  * @m: message to send
  * @dsz: amount of user data to be sent
  *
  * Message must have an destination specified explicitly.
  * Used for SOCK_RDM and SOCK_DGRAM messages,
  * and for 'SYN' messages on SOCK_SEQPACKET and SOCK_STREAM connections.
  * (Note: 'SYN+' is prohibited on SOCK_STREAM.)
  *
  * Return: the number of bytes sent on success, or errno otherwise
  */
 static int tipc_sendmsg(struct socket *sock,
             struct msghdr *m, size_t dsz)
 {
     struct sock *sk = sock->sk;
     int ret;
 
     lock_sock(sk);
     ret = __tipc_sendmsg(sock, m, dsz);
     release_sock(sk);
 
     return ret;
 }
 
 static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 {
     struct sock *sk = sock->sk;
     struct net *net = sock_net(sk);
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_uaddr *ua = (struct tipc_uaddr *)m->msg_name;
     long timeout = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
     struct list_head *clinks = &tsk->cong_links;
     bool syn = !tipc_sk_type_connectionless(sk);
     struct tipc_group *grp = tsk->group;
     struct tipc_msg *hdr = &tsk->phdr;
     struct tipc_socket_addr skaddr;
     struct sk_buff_head pkts;
     int atype, mtu, rc;
 
     if (unlikely(dlen > TIPC_MAX_USER_MSG_SIZE))
         return -EMSGSIZE;
 
     if (ua) {
         if (!tipc_uaddr_valid(ua, m->msg_namelen))
             return -EINVAL;
         atype = ua->addrtype;
     }
 
     /* If socket belongs to a communication group follow other paths */
     if (grp) {
         if (!ua)
             return tipc_send_group_bcast(sock, m, dlen, timeout);
         if (atype == TIPC_SERVICE_ADDR)
             return tipc_send_group_anycast(sock, m, dlen, timeout);
         if (atype == TIPC_SOCKET_ADDR)
             return tipc_send_group_unicast(sock, m, dlen, timeout);
         if (atype == TIPC_SERVICE_RANGE)
             return tipc_send_group_mcast(sock, m, dlen, timeout);
         return -EINVAL;
     }
 
     if (!ua) {
         ua = (struct tipc_uaddr *)&tsk->peer;
         if (!syn && ua->family != AF_TIPC)
             return -EDESTADDRREQ;
         atype = ua->addrtype;
     }
 
     if (unlikely(syn)) {
         if (sk->sk_state == TIPC_LISTEN)
             return -EPIPE;
         if (sk->sk_state != TIPC_OPEN)
             return -EISCONN;
         if (tsk->published)
             return -EOPNOTSUPP;
         if (atype == TIPC_SERVICE_ADDR)
             tsk->conn_addrtype = atype;
         msg_set_syn(hdr, 1);
     }
 
     memset(&skaddr, 0, sizeof(skaddr));
 
     /* Determine destination */
     if (atype == TIPC_SERVICE_RANGE) {
         return tipc_sendmcast(sock, ua, m, dlen, timeout);
     } else if (atype == TIPC_SERVICE_ADDR) {
         skaddr.node = ua->lookup_node;
         ua->scope = tipc_node2scope(skaddr.node);
         if (!tipc_nametbl_lookup_anycast(net, ua, &skaddr))
             return -EHOSTUNREACH;
     } else if (atype == TIPC_SOCKET_ADDR) {
         skaddr = ua->sk;
     } else {
         return -EINVAL;
     }
 
     /* Block or return if destination link is congested */
     rc = tipc_wait_for_cond(sock, &timeout,
                 !tipc_dest_find(clinks, skaddr.node, 0));
     if (unlikely(rc))
         return rc;
 
     /* Finally build message header */
     msg_set_destnode(hdr, skaddr.node);
     msg_set_destport(hdr, skaddr.ref);
     if (atype == TIPC_SERVICE_ADDR) {
         msg_set_type(hdr, TIPC_NAMED_MSG);
         msg_set_hdr_sz(hdr, NAMED_H_SIZE);
         msg_set_nametype(hdr, ua->sa.type);
         msg_set_nameinst(hdr, ua->sa.instance);
         msg_set_lookup_scope(hdr, ua->scope);
     } else { /* TIPC_SOCKET_ADDR */
         msg_set_type(hdr, TIPC_DIRECT_MSG);
         msg_set_lookup_scope(hdr, 0);
         msg_set_hdr_sz(hdr, BASIC_H_SIZE);
     }
 
     /* Add message body */
     __skb_queue_head_init(&pkts);
     mtu = tipc_node_get_mtu(net, skaddr.node, tsk->portid, true);
     rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
     if (unlikely(rc != dlen))
         return rc;
     if (unlikely(syn && !tipc_msg_skb_clone(&pkts, &sk->sk_write_queue))) {
         __skb_queue_purge(&pkts);
         return -ENOMEM;
     }
 
     /* Send message */
     trace_tipc_sk_sendmsg(sk, skb_peek(&pkts), TIPC_DUMP_SK_SNDQ, " ");
     rc = tipc_node_xmit(net, &pkts, skaddr.node, tsk->portid);
     if (unlikely(rc == -ELINKCONG)) {
         tipc_dest_push(clinks, skaddr.node, 0);
         tsk->cong_link_cnt++;
         rc = 0;
     }
 
     if (unlikely(syn && !rc)) {
         tipc_set_sk_state(sk, TIPC_CONNECTING);
         if (dlen && timeout) {
             timeout = msecs_to_jiffies(timeout);
             tipc_wait_for_connect(sock, &timeout);
         }
     }
 
     return rc ? rc : dlen;
 }
 
 /**
  * tipc_sendstream - send stream-oriented data
  * @sock: socket structure
  * @m: data to send
  * @dsz: total length of data to be transmitted
  *
  * Used for SOCK_STREAM data.
  *
  * Return: the number of bytes sent on success (or partial success),
  * or errno if no data sent
  */
 static int tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dsz)
 {
     struct sock *sk = sock->sk;
     int ret;
 
     lock_sock(sk);
     ret = __tipc_sendstream(sock, m, dsz);
     release_sock(sk);
 
     return ret;
 }
 
 static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dlen)
 {
     struct sock *sk = sock->sk;
     DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
     long timeout = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
     struct sk_buff_head *txq = &sk->sk_write_queue;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_msg *hdr = &tsk->phdr;
     struct net *net = sock_net(sk);
     struct sk_buff *skb;
     u32 dnode = tsk_peer_node(tsk);
     int maxnagle = tsk->maxnagle;
     int maxpkt = tsk->max_pkt;
     int send, sent = 0;
     int blocks, rc = 0;
 
     if (unlikely(dlen > INT_MAX))
         return -EMSGSIZE;
 
     /* Handle implicit connection setup */
     if (unlikely(dest && sk->sk_state == TIPC_OPEN)) {
         rc = __tipc_sendmsg(sock, m, dlen);
         if (dlen && dlen == rc) {
             tsk->peer_caps = tipc_node_get_capabilities(net, dnode);
             tsk->snt_unacked = tsk_inc(tsk, dlen + msg_hdr_sz(hdr));
         }
         return rc;
     }
 
     do {
         rc = tipc_wait_for_cond(sock, &timeout,
                     (!tsk->cong_link_cnt &&
                      !tsk_conn_cong(tsk) &&
                      tipc_sk_connected(sk)));
         if (unlikely(rc))
             break;
         send = min_t(size_t, dlen - sent, TIPC_MAX_USER_MSG_SIZE);
         blocks = tsk->snd_backlog;
         if (tsk->oneway++ >= tsk->nagle_start && maxnagle &&
             send <= maxnagle) {
             rc = tipc_msg_append(hdr, m, send, maxnagle, txq);
             if (unlikely(rc < 0))
                 break;
             blocks += rc;
             tsk->msg_acc++;
             if (blocks <= 64 && tsk->expect_ack) {
                 tsk->snd_backlog = blocks;
                 sent += send;
                 break;
             } else if (blocks > 64) {
                 tsk->pkt_cnt += skb_queue_len(txq);
             } else {
                 skb = skb_peek_tail(txq);
                 if (skb) {
                     msg_set_ack_required(buf_msg(skb));
                     tsk->expect_ack = true;
                 } else {
                     tsk->expect_ack = false;
                 }
                 tsk->msg_acc = 0;
                 tsk->pkt_cnt = 0;
             }
         } else {
             rc = tipc_msg_build(hdr, m, sent, send, maxpkt, txq);
             if (unlikely(rc != send))
                 break;
             blocks += tsk_inc(tsk, send + MIN_H_SIZE);
         }
         trace_tipc_sk_sendstream(sk, skb_peek(txq),
                      TIPC_DUMP_SK_SNDQ, " ");
         rc = tipc_node_xmit(net, txq, dnode, tsk->portid);
         if (unlikely(rc == -ELINKCONG)) {
             tsk->cong_link_cnt = 1;
             rc = 0;
         }
         if (likely(!rc)) {
             tsk->snt_unacked += blocks;
             tsk->snd_backlog = 0;
             sent += send;
         }
     } while (sent < dlen && !rc);
 
     return sent ? sent : rc;
 }
 
 /**
  * tipc_send_packet - send a connection-oriented message
  * @sock: socket structure
  * @m: message to send
  * @dsz: length of data to be transmitted
  *
  * Used for SOCK_SEQPACKET messages.
  *
  * Return: the number of bytes sent on success, or errno otherwise
  */
 static int tipc_send_packet(struct socket *sock, struct msghdr *m, size_t dsz)
 {
     if (dsz > TIPC_MAX_USER_MSG_SIZE)
         return -EMSGSIZE;
 
     return tipc_sendstream(sock, m, dsz);
 }
 
 /* tipc_sk_finish_conn - complete the setup of a connection
  */
 static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
                 u32 peer_node)
 {
     struct sock *sk = &tsk->sk;
     struct net *net = sock_net(sk);
     struct tipc_msg *msg = &tsk->phdr;
 
     msg_set_syn(msg, 0);
     msg_set_destnode(msg, peer_node);
     msg_set_destport(msg, peer_port);
     msg_set_type(msg, TIPC_CONN_MSG);
     msg_set_lookup_scope(msg, 0);
     msg_set_hdr_sz(msg, SHORT_H_SIZE);
 
     sk_reset_timer(sk, &sk->sk_timer, jiffies + CONN_PROBING_INTV);
     tipc_set_sk_state(sk, TIPC_ESTABLISHED);
     tipc_node_add_conn(net, peer_node, tsk->portid, peer_port);
     tsk->max_pkt = tipc_node_get_mtu(net, peer_node, tsk->portid, true);
     tsk->peer_caps = tipc_node_get_capabilities(net, peer_node);
     tsk_set_nagle(tsk);
     __skb_queue_purge(&sk->sk_write_queue);
     if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)
         return;
 
     /* Fall back to message based flow control */
     tsk->rcv_win = FLOWCTL_MSG_WIN;
     tsk->snd_win = FLOWCTL_MSG_WIN;
 }
 
 /**
  * tipc_sk_set_orig_addr - capture sender's address for received message
  * @m: descriptor for message info
  * @skb: received message
  *
  * Note: Address is not captured if not requested by receiver.
  */
 static void tipc_sk_set_orig_addr(struct msghdr *m, struct sk_buff *skb)
 {
     DECLARE_SOCKADDR(struct sockaddr_pair *, srcaddr, m->msg_name);
     struct tipc_msg *hdr = buf_msg(skb);
 
     if (!srcaddr)
         return;
 
     srcaddr->sock.family = AF_TIPC;
     srcaddr->sock.addrtype = TIPC_SOCKET_ADDR;
     srcaddr->sock.scope = 0;
     srcaddr->sock.addr.id.ref = msg_origport(hdr);
     srcaddr->sock.addr.id.node = msg_orignode(hdr);
     srcaddr->sock.addr.name.domain = 0;
     m->msg_namelen = sizeof(struct sockaddr_tipc);
 
     if (!msg_in_group(hdr))
         return;
 
     /* Group message users may also want to know sending member's id */
     srcaddr->member.family = AF_TIPC;
     srcaddr->member.addrtype = TIPC_SERVICE_ADDR;
     srcaddr->member.scope = 0;
     srcaddr->member.addr.name.name.type = msg_nametype(hdr);
     srcaddr->member.addr.name.name.instance = TIPC_SKB_CB(skb)->orig_member;
     srcaddr->member.addr.name.domain = 0;
     m->msg_namelen = sizeof(*srcaddr);
 }
 
 /**
  * tipc_sk_anc_data_recv - optionally capture ancillary data for received message
  * @m: descriptor for message info
  * @skb: received message buffer
  * @tsk: TIPC port associated with message
  *
  * Note: Ancillary data is not captured if not requested by receiver.
  *
  * Return: 0 if successful, otherwise errno
  */
 static int tipc_sk_anc_data_recv(struct msghdr *m, struct sk_buff *skb,
                  struct tipc_sock *tsk)
 {
     struct tipc_msg *hdr;
     u32 data[3] = {0,};
     bool has_addr;
     int dlen, rc;
 
     if (likely(m->msg_controllen == 0))
         return 0;
 
     hdr = buf_msg(skb);
     dlen = msg_data_sz(hdr);
 
     /* Capture errored message object, if any */
     if (msg_errcode(hdr)) {
         if (skb_linearize(skb))
             return -ENOMEM;
         hdr = buf_msg(skb);
         data[0] = msg_errcode(hdr);
         data[1] = dlen;
         rc = put_cmsg(m, SOL_TIPC, TIPC_ERRINFO, 8, data);
         if (rc || !dlen)
             return rc;
         rc = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, dlen, msg_data(hdr));
         if (rc)
             return rc;
     }
 
     /* Capture TIPC_SERVICE_ADDR/RANGE destination address, if any */
     switch (msg_type(hdr)) {
     case TIPC_NAMED_MSG:
         has_addr = true;
         data[0] = msg_nametype(hdr);
         data[1] = msg_namelower(hdr);
         data[2] = data[1];
         break;
     case TIPC_MCAST_MSG:
         has_addr = true;
         data[0] = msg_nametype(hdr);
         data[1] = msg_namelower(hdr);
         data[2] = msg_nameupper(hdr);
         break;
     case TIPC_CONN_MSG:
         has_addr = !!tsk->conn_addrtype;
         data[0] = msg_nametype(&tsk->phdr);
         data[1] = msg_nameinst(&tsk->phdr);
         data[2] = data[1];
         break;
     default:
         has_addr = false;
     }
     if (!has_addr)
         return 0;
     return put_cmsg(m, SOL_TIPC, TIPC_DESTNAME, 12, data);
 }
 
 static struct sk_buff *tipc_sk_build_ack(struct tipc_sock *tsk)
 {
     struct sock *sk = &tsk->sk;
     struct sk_buff *skb = NULL;
     struct tipc_msg *msg;
     u32 peer_port = tsk_peer_port(tsk);
     u32 dnode = tsk_peer_node(tsk);
 
     if (!tipc_sk_connected(sk))
         return NULL;
     skb = tipc_msg_create(CONN_MANAGER, CONN_ACK, INT_H_SIZE, 0,
                   dnode, tsk_own_node(tsk), peer_port,
                   tsk->portid, TIPC_OK);
     if (!skb)
         return NULL;
     msg = buf_msg(skb);
     msg_set_conn_ack(msg, tsk->rcv_unacked);
     tsk->rcv_unacked = 0;
 
     /* Adjust to and advertize the correct window limit */
     if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL) {
         tsk->rcv_win = tsk_adv_blocks(tsk->sk.sk_rcvbuf);
         msg_set_adv_win(msg, tsk->rcv_win);
     }
     return skb;
 }
 
 static void tipc_sk_send_ack(struct tipc_sock *tsk)
 {
     struct sk_buff *skb;
 
     skb = tipc_sk_build_ack(tsk);
     if (!skb)
         return;
 
     tipc_node_xmit_skb(sock_net(&tsk->sk), skb, tsk_peer_node(tsk),
                msg_link_selector(buf_msg(skb)));
 }
 
 static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 {
     struct sock *sk = sock->sk;
     DEFINE_WAIT_FUNC(wait, woken_wake_function);
     long timeo = *timeop;
     int err = sock_error(sk);
 
     if (err)
         return err;
 
     for (;;) {
         if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
             if (sk->sk_shutdown & RCV_SHUTDOWN) {
                 err = -ENOTCONN;
                 break;
             }
             add_wait_queue(sk_sleep(sk), &wait);
             release_sock(sk);
             timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
             sched_annotate_sleep();
             lock_sock(sk);
             remove_wait_queue(sk_sleep(sk), &wait);
         }
         err = 0;
         if (!skb_queue_empty(&sk->sk_receive_queue))
             break;
         err = -EAGAIN;
         if (!timeo)
             break;
         err = sock_intr_errno(timeo);
         if (signal_pending(current))
             break;
 
         err = sock_error(sk);
         if (err)
             break;
     }
     *timeop = timeo;
     return err;
 }
 
 /**
  * tipc_recvmsg - receive packet-oriented message
  * @sock: network socket
  * @m: descriptor for message info
  * @buflen: length of user buffer area
  * @flags: receive flags
  *
  * Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
  * If the complete message doesn't fit in user area, truncate it.
  *
  * Return: size of returned message data, errno otherwise
  */
 static int tipc_recvmsg(struct socket *sock, struct msghdr *m,
             size_t buflen,  int flags)
 {
     struct sock *sk = sock->sk;
     bool connected = !tipc_sk_type_connectionless(sk);
     struct tipc_sock *tsk = tipc_sk(sk);
     int rc, err, hlen, dlen, copy;
     struct tipc_skb_cb *skb_cb;
     struct sk_buff_head xmitq;
     struct tipc_msg *hdr;
     struct sk_buff *skb;
     bool grp_evt;
     long timeout;
 
     /* Catch invalid receive requests */
     if (unlikely(!buflen))
         return -EINVAL;
 
     lock_sock(sk);
     if (unlikely(connected && sk->sk_state == TIPC_OPEN)) {
         rc = -ENOTCONN;
         goto exit;
     }
     timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 
     /* Step rcv queue to first msg with data or error; wait if necessary */
     do {
         rc = tipc_wait_for_rcvmsg(sock, &timeout);
         if (unlikely(rc))
             goto exit;
         skb = skb_peek(&sk->sk_receive_queue);
         skb_cb = TIPC_SKB_CB(skb);
         hdr = buf_msg(skb);
         dlen = msg_data_sz(hdr);
         hlen = msg_hdr_sz(hdr);
         err = msg_errcode(hdr);
         grp_evt = msg_is_grp_evt(hdr);
         if (likely(dlen || err))
             break;
         tsk_advance_rx_queue(sk);
     } while (1);
 
     /* Collect msg meta data, including error code and rejected data */
     tipc_sk_set_orig_addr(m, skb);
     rc = tipc_sk_anc_data_recv(m, skb, tsk);
     if (unlikely(rc))
         goto exit;
     hdr = buf_msg(skb);
 
     /* Capture data if non-error msg, otherwise just set return value */
     if (likely(!err)) {
         int offset = skb_cb->bytes_read;
 
         copy = min_t(int, dlen - offset, buflen);
         rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);
         if (unlikely(rc))
             goto exit;
         if (unlikely(offset + copy < dlen)) {
             if (flags & MSG_EOR) {
                 if (!(flags & MSG_PEEK))
                     skb_cb->bytes_read = offset + copy;
             } else {
                 m->msg_flags |= MSG_TRUNC;
                 skb_cb->bytes_read = 0;
             }
         } else {
             if (flags & MSG_EOR)
                 m->msg_flags |= MSG_EOR;
             skb_cb->bytes_read = 0;
         }
     } else {
         copy = 0;
         rc = 0;
         if (err != TIPC_CONN_SHUTDOWN && connected && !m->msg_control) {
             rc = -ECONNRESET;
             goto exit;
         }
     }
 
     /* Mark message as group event if applicable */
     if (unlikely(grp_evt)) {
         if (msg_grp_evt(hdr) == TIPC_WITHDRAWN)
             m->msg_flags |= MSG_EOR;
         m->msg_flags |= MSG_OOB;
         copy = 0;
     }
 
     /* Caption of data or error code/rejected data was successful */
     if (unlikely(flags & MSG_PEEK))
         goto exit;
 
     /* Send group flow control advertisement when applicable */
     if (tsk->group && msg_in_group(hdr) && !grp_evt) {
         __skb_queue_head_init(&xmitq);
         tipc_group_update_rcv_win(tsk->group, tsk_blocks(hlen + dlen),
                       msg_orignode(hdr), msg_origport(hdr),
                       &xmitq);
         tipc_node_distr_xmit(sock_net(sk), &xmitq);
     }
 
     if (skb_cb->bytes_read)
         goto exit;
 
     tsk_advance_rx_queue(sk);
 
     if (likely(!connected))
         goto exit;
 
     /* Send connection flow control advertisement when applicable */
     tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);
     if (tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE)
         tipc_sk_send_ack(tsk);
 exit:
     release_sock(sk);
     return rc ? rc : copy;
 }
 
 /**
  * tipc_recvstream - receive stream-oriented data
  * @sock: network socket
  * @m: descriptor for message info
  * @buflen: total size of user buffer area
  * @flags: receive flags
  *
  * Used for SOCK_STREAM messages only.  If not enough data is available
  * will optionally wait for more; never truncates data.
  *
  * Return: size of returned message data, errno otherwise
  */
 static int tipc_recvstream(struct socket *sock, struct msghdr *m,
                size_t buflen, int flags)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct sk_buff *skb;
     struct tipc_msg *hdr;
     struct tipc_skb_cb *skb_cb;
     bool peek = flags & MSG_PEEK;
     int offset, required, copy, copied = 0;
     int hlen, dlen, err, rc;
     long timeout;
 
     /* Catch invalid receive attempts */
     if (unlikely(!buflen))
         return -EINVAL;
 
     lock_sock(sk);
 
     if (unlikely(sk->sk_state == TIPC_OPEN)) {
         rc = -ENOTCONN;
         goto exit;
     }
     required = sock_rcvlowat(sk, flags & MSG_WAITALL, buflen);
     timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 
     do {
         /* Look at first msg in receive queue; wait if necessary */
         rc = tipc_wait_for_rcvmsg(sock, &timeout);
         if (unlikely(rc))
             break;
         skb = skb_peek(&sk->sk_receive_queue);
         skb_cb = TIPC_SKB_CB(skb);
         hdr = buf_msg(skb);
         dlen = msg_data_sz(hdr);
         hlen = msg_hdr_sz(hdr);
         err = msg_errcode(hdr);
 
         /* Discard any empty non-errored (SYN-) message */
         if (unlikely(!dlen && !err)) {
             tsk_advance_rx_queue(sk);
             continue;
         }
 
         /* Collect msg meta data, incl. error code and rejected data */
         if (!copied) {
             tipc_sk_set_orig_addr(m, skb);
             rc = tipc_sk_anc_data_recv(m, skb, tsk);
             if (rc)
                 break;
             hdr = buf_msg(skb);
         }
 
         /* Copy data if msg ok, otherwise return error/partial data */
         if (likely(!err)) {
             offset = skb_cb->bytes_read;
             copy = min_t(int, dlen - offset, buflen - copied);
             rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);
             if (unlikely(rc))
                 break;
             copied += copy;
             offset += copy;
             if (unlikely(offset < dlen)) {
                 if (!peek)
                     skb_cb->bytes_read = offset;
                 break;
             }
         } else {
             rc = 0;
             if ((err != TIPC_CONN_SHUTDOWN) && !m->msg_control)
                 rc = -ECONNRESET;
             if (copied || rc)
                 break;
         }
 
         if (unlikely(peek))
             break;
 
         tsk_advance_rx_queue(sk);
 
         /* Send connection flow control advertisement when applicable */
         tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);
         if (tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE)
             tipc_sk_send_ack(tsk);
 
         /* Exit if all requested data or FIN/error received */
         if (copied == buflen || err)
             break;
 
     } while (!skb_queue_empty(&sk->sk_receive_queue) || copied < required);
 exit:
     release_sock(sk);
     return copied ? copied : rc;
 }
 
 /**
  * tipc_write_space - wake up thread if port congestion is released
  * @sk: socket
  */
 static void tipc_write_space(struct sock *sk)
 {
     struct socket_wq *wq;
 
     rcu_read_lock();
     wq = rcu_dereference(sk->sk_wq);
     if (skwq_has_sleeper(wq))
         wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
                         EPOLLWRNORM | EPOLLWRBAND);
     rcu_read_unlock();
 }
 
 /**
  * tipc_data_ready - wake up threads to indicate messages have been received
  * @sk: socket
  */
 static void tipc_data_ready(struct sock *sk)
 {
     struct socket_wq *wq;
 
     rcu_read_lock();
     wq = rcu_dereference(sk->sk_wq);
     if (skwq_has_sleeper(wq))
         wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
                         EPOLLRDNORM | EPOLLRDBAND);
     rcu_read_unlock();
 }
 
 static void tipc_sock_destruct(struct sock *sk)
 {
     __skb_queue_purge(&sk->sk_receive_queue);
 }
 
 static void tipc_sk_proto_rcv(struct sock *sk,
                   struct sk_buff_head *inputq,
                   struct sk_buff_head *xmitq)
 {
     struct sk_buff *skb = __skb_dequeue(inputq);
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_msg *hdr = buf_msg(skb);
     struct tipc_group *grp = tsk->group;
     bool wakeup = false;
 
     switch (msg_user(hdr)) {
     case CONN_MANAGER:
         tipc_sk_conn_proto_rcv(tsk, skb, inputq, xmitq);
         return;
     case SOCK_WAKEUP:
         tipc_dest_del(&tsk->cong_links, msg_orignode(hdr), 0);
         /* coupled with smp_rmb() in tipc_wait_for_cond() */
         smp_wmb();
         tsk->cong_link_cnt--;
         wakeup = true;
         tipc_sk_push_backlog(tsk, false);
         break;
     case GROUP_PROTOCOL:
         tipc_group_proto_rcv(grp, &wakeup, hdr, inputq, xmitq);
         break;
     case TOP_SRV:
         tipc_group_member_evt(tsk->group, &wakeup, &sk->sk_rcvbuf,
                       hdr, inputq, xmitq);
         break;
     default:
         break;
     }
 
     if (wakeup)
         sk->sk_write_space(sk);
 
     kfree_skb(skb);
 }
 
 /**
  * tipc_sk_filter_connect - check incoming message for a connection-based socket
  * @tsk: TIPC socket
  * @skb: pointer to message buffer.
  * @xmitq: for Nagle ACK if any
  * Return: true if message should be added to receive queue, false otherwise
  */
 static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb,
                    struct sk_buff_head *xmitq)
 {
     struct sock *sk = &tsk->sk;
     struct net *net = sock_net(sk);
     struct tipc_msg *hdr = buf_msg(skb);
     bool con_msg = msg_connected(hdr);
     u32 pport = tsk_peer_port(tsk);
     u32 pnode = tsk_peer_node(tsk);
     u32 oport = msg_origport(hdr);
     u32 onode = msg_orignode(hdr);
     int err = msg_errcode(hdr);
     unsigned long delay;
 
     if (unlikely(msg_mcast(hdr)))
         return false;
     tsk->oneway = 0;
 
     switch (sk->sk_state) {
     case TIPC_CONNECTING:
         /* Setup ACK */
         if (likely(con_msg)) {
             if (err)
                 break;
             tipc_sk_finish_conn(tsk, oport, onode);
             msg_set_importance(&tsk->phdr, msg_importance(hdr));
             /* ACK+ message with data is added to receive queue */
             if (msg_data_sz(hdr))
                 return true;
             /* Empty ACK-, - wake up sleeping connect() and drop */
             sk->sk_state_change(sk);
             msg_set_dest_droppable(hdr, 1);
             return false;
         }
         /* Ignore connectionless message if not from listening socket */
         if (oport != pport || onode != pnode)
             return false;
 
         /* Rejected SYN */
         if (err != TIPC_ERR_OVERLOAD)
             break;
 
         /* Prepare for new setup attempt if we have a SYN clone */
         if (skb_queue_empty(&sk->sk_write_queue))
             break;
         get_random_bytes(&delay, 2);
         delay %= (tsk->conn_timeout / 4);
         delay = msecs_to_jiffies(delay + 100);
         sk_reset_timer(sk, &sk->sk_timer, jiffies + delay);
         return false;
     case TIPC_OPEN:
     case TIPC_DISCONNECTING:
         return false;
     case TIPC_LISTEN:
         /* Accept only SYN message */
         if (!msg_is_syn(hdr) &&
             tipc_node_get_capabilities(net, onode) & TIPC_SYN_BIT)
             return false;
         if (!con_msg && !err)
             return true;
         return false;
     case TIPC_ESTABLISHED:
         if (!skb_queue_empty(&sk->sk_write_queue))
             tipc_sk_push_backlog(tsk, false);
         /* Accept only connection-based messages sent by peer */
         if (likely(con_msg && !err && pport == oport &&
                pnode == onode)) {
             if (msg_ack_required(hdr)) {
                 struct sk_buff *skb;
 
                 skb = tipc_sk_build_ack(tsk);
                 if (skb) {
                     msg_set_nagle_ack(buf_msg(skb));
                     __skb_queue_tail(xmitq, skb);
                 }
             }
             return true;
         }
         if (!tsk_peer_msg(tsk, hdr))
             return false;
         if (!err)
             return true;
         tipc_set_sk_state(sk, TIPC_DISCONNECTING);
         tipc_node_remove_conn(net, pnode, tsk->portid);
         sk->sk_state_change(sk);
         return true;
     default:
         pr_err("Unknown sk_state %u\n", sk->sk_state);
     }
     /* Abort connection setup attempt */
     tipc_set_sk_state(sk, TIPC_DISCONNECTING);
     sk->sk_err = ECONNREFUSED;
     sk->sk_state_change(sk);
     return true;
 }
 
 /**
  * rcvbuf_limit - get proper overload limit of socket receive queue
  * @sk: socket
  * @skb: message
  *
  * For connection oriented messages, irrespective of importance,
  * default queue limit is 2 MB.
  *
  * For connectionless messages, queue limits are based on message
  * importance as follows:
  *
  * TIPC_LOW_IMPORTANCE       (2 MB)
  * TIPC_MEDIUM_IMPORTANCE    (4 MB)
  * TIPC_HIGH_IMPORTANCE      (8 MB)
  * TIPC_CRITICAL_IMPORTANCE  (16 MB)
  *
  * Return: overload limit according to corresponding message importance
  */
 static unsigned int rcvbuf_limit(struct sock *sk, struct sk_buff *skb)
 {
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_msg *hdr = buf_msg(skb);
 
     if (unlikely(msg_in_group(hdr)))
         return READ_ONCE(sk->sk_rcvbuf);
 
     if (unlikely(!msg_connected(hdr)))
         return READ_ONCE(sk->sk_rcvbuf) << msg_importance(hdr);
 
     if (likely(tsk->peer_caps & TIPC_BLOCK_FLOWCTL))
         return READ_ONCE(sk->sk_rcvbuf);
 
     return FLOWCTL_MSG_LIM;
 }
 
 /**
  * tipc_sk_filter_rcv - validate incoming message
  * @sk: socket
  * @skb: pointer to message.
  * @xmitq: output message area (FIXME)
  *
  * Enqueues message on receive queue if acceptable; optionally handles
  * disconnect indication for a connected socket.
  *
  * Called with socket lock already taken
  */
 static void tipc_sk_filter_rcv(struct sock *sk, struct sk_buff *skb,
                    struct sk_buff_head *xmitq)
 {
     bool sk_conn = !tipc_sk_type_connectionless(sk);
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_group *grp = tsk->group;
     struct tipc_msg *hdr = buf_msg(skb);
     struct net *net = sock_net(sk);
     struct sk_buff_head inputq;
     int mtyp = msg_type(hdr);
     int limit, err = TIPC_OK;
 
     trace_tipc_sk_filter_rcv(sk, skb, TIPC_DUMP_ALL, " ");
     TIPC_SKB_CB(skb)->bytes_read = 0;
     __skb_queue_head_init(&inputq);
     __skb_queue_tail(&inputq, skb);
 
     if (unlikely(!msg_isdata(hdr)))
         tipc_sk_proto_rcv(sk, &inputq, xmitq);
 
     if (unlikely(grp))
         tipc_group_filter_msg(grp, &inputq, xmitq);
 
     if (unlikely(!grp) && mtyp == TIPC_MCAST_MSG)
         tipc_mcast_filter_msg(net, &tsk->mc_method.deferredq, &inputq);
 
     /* Validate and add to receive buffer if there is space */
     while ((skb = __skb_dequeue(&inputq))) {
         hdr = buf_msg(skb);
         limit = rcvbuf_limit(sk, skb);
         if ((sk_conn && !tipc_sk_filter_connect(tsk, skb, xmitq)) ||
             (!sk_conn && msg_connected(hdr)) ||
             (!grp && msg_in_group(hdr)))
             err = TIPC_ERR_NO_PORT;
         else if (sk_rmem_alloc_get(sk) + skb->truesize >= limit) {
             trace_tipc_sk_dump(sk, skb, TIPC_DUMP_ALL,
                        "err_overload2!");
             atomic_inc(&sk->sk_drops);
             err = TIPC_ERR_OVERLOAD;
         }
 
         if (unlikely(err)) {
             if (tipc_msg_reverse(tipc_own_addr(net), &skb, err)) {
                 trace_tipc_sk_rej_msg(sk, skb, TIPC_DUMP_NONE,
                               "@filter_rcv!");
                 __skb_queue_tail(xmitq, skb);
             }
             err = TIPC_OK;
             continue;
         }
         __skb_queue_tail(&sk->sk_receive_queue, skb);
         skb_set_owner_r(skb, sk);
         trace_tipc_sk_overlimit2(sk, skb, TIPC_DUMP_ALL,
                      "rcvq >90% allocated!");
         sk->sk_data_ready(sk);
     }
 }
 
 /**
  * tipc_sk_backlog_rcv - handle incoming message from backlog queue
  * @sk: socket
  * @skb: message
  *
  * Caller must hold socket lock
  */
 static int tipc_sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 {
     unsigned int before = sk_rmem_alloc_get(sk);
     struct sk_buff_head xmitq;
     unsigned int added;
 
     __skb_queue_head_init(&xmitq);
 
     tipc_sk_filter_rcv(sk, skb, &xmitq);
     added = sk_rmem_alloc_get(sk) - before;
     atomic_add(added, &tipc_sk(sk)->dupl_rcvcnt);
 
     /* Send pending response/rejected messages, if any */
     tipc_node_distr_xmit(sock_net(sk), &xmitq);
     return 0;
 }
 
 /**
  * tipc_sk_enqueue - extract all buffers with destination 'dport' from
  *                   inputq and try adding them to socket or backlog queue
  * @inputq: list of incoming buffers with potentially different destinations
  * @sk: socket where the buffers should be enqueued
  * @dport: port number for the socket
  * @xmitq: output queue
  *
  * Caller must hold socket lock
  */
 static void tipc_sk_enqueue(struct sk_buff_head *inputq, struct sock *sk,
                 u32 dport, struct sk_buff_head *xmitq)
 {
     unsigned long time_limit = jiffies + usecs_to_jiffies(20000);
     struct sk_buff *skb;
     unsigned int lim;
     atomic_t *dcnt;
     u32 onode;
 
     while (skb_queue_len(inputq)) {
         if (unlikely(time_after_eq(jiffies, time_limit)))
             return;
 
         skb = tipc_skb_dequeue(inputq, dport);
         if (unlikely(!skb))
             return;
 
         /* Add message directly to receive queue if possible */
         if (!sock_owned_by_user(sk)) {
             tipc_sk_filter_rcv(sk, skb, xmitq);
             continue;
         }
 
         /* Try backlog, compensating for double-counted bytes */
         dcnt = &tipc_sk(sk)->dupl_rcvcnt;
         if (!sk->sk_backlog.len)
             atomic_set(dcnt, 0);
         lim = rcvbuf_limit(sk, skb) + atomic_read(dcnt);
         if (likely(!sk_add_backlog(sk, skb, lim))) {
             trace_tipc_sk_overlimit1(sk, skb, TIPC_DUMP_ALL,
                          "bklg & rcvq >90% allocated!");
             continue;
         }
 
         trace_tipc_sk_dump(sk, skb, TIPC_DUMP_ALL, "err_overload!");
         /* Overload => reject message back to sender */
         onode = tipc_own_addr(sock_net(sk));
         atomic_inc(&sk->sk_drops);
         if (tipc_msg_reverse(onode, &skb, TIPC_ERR_OVERLOAD)) {
             trace_tipc_sk_rej_msg(sk, skb, TIPC_DUMP_ALL,
                           "@sk_enqueue!");
             __skb_queue_tail(xmitq, skb);
         }
         break;
     }
 }
 
 /**
  * tipc_sk_rcv - handle a chain of incoming buffers
  * @net: the associated network namespace
  * @inputq: buffer list containing the buffers
  * Consumes all buffers in list until inputq is empty
  * Note: may be called in multiple threads referring to the same queue
  */
 void tipc_sk_rcv(struct net *net, struct sk_buff_head *inputq)
 {
     struct sk_buff_head xmitq;
     u32 dnode, dport = 0;
     int err;
     struct tipc_sock *tsk;
     struct sock *sk;
     struct sk_buff *skb;
 
     __skb_queue_head_init(&xmitq);
     while (skb_queue_len(inputq)) {
         dport = tipc_skb_peek_port(inputq, dport);
         tsk = tipc_sk_lookup(net, dport);
 
         if (likely(tsk)) {
             sk = &tsk->sk;
             if (likely(spin_trylock_bh(&sk->sk_lock.slock))) {
                 tipc_sk_enqueue(inputq, sk, dport, &xmitq);
                 spin_unlock_bh(&sk->sk_lock.slock);
             }
             /* Send pending response/rejected messages, if any */
             tipc_node_distr_xmit(sock_net(sk), &xmitq);
             sock_put(sk);
             continue;
         }
         /* No destination socket => dequeue skb if still there */
         skb = tipc_skb_dequeue(inputq, dport);
         if (!skb)
             return;
 
         /* Try secondary lookup if unresolved named message */
         err = TIPC_ERR_NO_PORT;
         if (tipc_msg_lookup_dest(net, skb, &err))
             goto xmit;
 
         /* Prepare for message rejection */
         if (!tipc_msg_reverse(tipc_own_addr(net), &skb, err))
             continue;
 
         trace_tipc_sk_rej_msg(NULL, skb, TIPC_DUMP_NONE, "@sk_rcv!");
 xmit:
         dnode = msg_destnode(buf_msg(skb));
         tipc_node_xmit_skb(net, skb, dnode, dport);
     }
 }
 
 static int tipc_wait_for_connect(struct socket *sock, long *timeo_p)
 {
     DEFINE_WAIT_FUNC(wait, woken_wake_function);
     struct sock *sk = sock->sk;
     int done;
 
     do {
         int err = sock_error(sk);
         if (err)
             return err;
         if (!*timeo_p)
             return -ETIMEDOUT;
         if (signal_pending(current))
             return sock_intr_errno(*timeo_p);
         if (sk->sk_state == TIPC_DISCONNECTING)
             break;
 
         add_wait_queue(sk_sleep(sk), &wait);
         done = sk_wait_event(sk, timeo_p, tipc_sk_connected(sk),
                      &wait);
         remove_wait_queue(sk_sleep(sk), &wait);
     } while (!done);
     return 0;
 }
 
 static bool tipc_sockaddr_is_sane(struct sockaddr_tipc *addr)
 {
     if (addr->family != AF_TIPC)
         return false;
     if (addr->addrtype == TIPC_SERVICE_RANGE)
         return (addr->addr.nameseq.lower <= addr->addr.nameseq.upper);
     return (addr->addrtype == TIPC_SERVICE_ADDR ||
         addr->addrtype == TIPC_SOCKET_ADDR);
 }
 
 /**
  * tipc_connect - establish a connection to another TIPC port
  * @sock: socket structure
  * @dest: socket address for destination port
  * @destlen: size of socket address data structure
  * @flags: file-related flags associated with socket
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_connect(struct socket *sock, struct sockaddr *dest,
             int destlen, int flags)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct sockaddr_tipc *dst = (struct sockaddr_tipc *)dest;
     struct msghdr m = {NULL,};
     long timeout = (flags & O_NONBLOCK) ? 0 : tsk->conn_timeout;
     int previous;
     int res = 0;
 
     if (destlen != sizeof(struct sockaddr_tipc))
         return -EINVAL;
 
     lock_sock(sk);
 
     if (tsk->group) {
         res = -EINVAL;
         goto exit;
     }
 
     if (dst->family == AF_UNSPEC) {
         memset(&tsk->peer, 0, sizeof(struct sockaddr_tipc));
         if (!tipc_sk_type_connectionless(sk))
             res = -EINVAL;
         goto exit;
     }
     if (!tipc_sockaddr_is_sane(dst)) {
         res = -EINVAL;
         goto exit;
     }
     /* DGRAM/RDM connect(), just save the destaddr */
     if (tipc_sk_type_connectionless(sk)) {
         memcpy(&tsk->peer, dest, destlen);
         goto exit;
     } else if (dst->addrtype == TIPC_SERVICE_RANGE) {
         res = -EINVAL;
         goto exit;
     }
 
     previous = sk->sk_state;
 
     switch (sk->sk_state) {
     case TIPC_OPEN:
         /* Send a 'SYN-' to destination */
         m.msg_name = dest;
         m.msg_namelen = destlen;
 
         /* If connect is in non-blocking case, set MSG_DONTWAIT to
          * indicate send_msg() is never blocked.
          */
         if (!timeout)
             m.msg_flags = MSG_DONTWAIT;
 
         res = __tipc_sendmsg(sock, &m, 0);
         if ((res < 0) && (res != -EWOULDBLOCK))
             goto exit;
 
         /* Just entered TIPC_CONNECTING state; the only
          * difference is that return value in non-blocking
          * case is EINPROGRESS, rather than EALREADY.
          */
         res = -EINPROGRESS;
         fallthrough;
     case TIPC_CONNECTING:
         if (!timeout) {
             if (previous == TIPC_CONNECTING)
                 res = -EALREADY;
             goto exit;
         }
         timeout = msecs_to_jiffies(timeout);
         /* Wait until an 'ACK' or 'RST' arrives, or a timeout occurs */
         res = tipc_wait_for_connect(sock, &timeout);
         break;
     case TIPC_ESTABLISHED:
         res = -EISCONN;
         break;
     default:
         res = -EINVAL;
     }
 
 exit:
     release_sock(sk);
     return res;
 }
 
 /**
  * tipc_listen - allow socket to listen for incoming connections
  * @sock: socket structure
  * @len: (unused)
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_listen(struct socket *sock, int len)
 {
     struct sock *sk = sock->sk;
     int res;
 
     lock_sock(sk);
     res = tipc_set_sk_state(sk, TIPC_LISTEN);
     release_sock(sk);
 
     return res;
 }
 
 static int tipc_wait_for_accept(struct socket *sock, long timeo)
 {
     struct sock *sk = sock->sk;
     DEFINE_WAIT_FUNC(wait, woken_wake_function);
     int err;
 
     /* True wake-one mechanism for incoming connections: only
      * one process gets woken up, not the 'whole herd'.
      * Since we do not 'race & poll' for established sockets
      * anymore, the common case will execute the loop only once.
     */
     for (;;) {
         if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
             add_wait_queue(sk_sleep(sk), &wait);
             release_sock(sk);
             timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
             lock_sock(sk);
             remove_wait_queue(sk_sleep(sk), &wait);
         }
         err = 0;
         if (!skb_queue_empty(&sk->sk_receive_queue))
             break;
         err = -EAGAIN;
         if (!timeo)
             break;
         err = sock_intr_errno(timeo);
         if (signal_pending(current))
             break;
     }
     return err;
 }
 
 /**
  * tipc_accept - wait for connection request
  * @sock: listening socket
  * @new_sock: new socket that is to be connected
  * @flags: file-related flags associated with socket
  * @kern: caused by kernel or by userspace?
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags,
                bool kern)
 {
     struct sock *new_sk, *sk = sock->sk;
     struct tipc_sock *new_tsock;
     struct msghdr m = {NULL,};
     struct tipc_msg *msg;
     struct sk_buff *buf;
     long timeo;
     int res;
 
     lock_sock(sk);
 
     if (sk->sk_state != TIPC_LISTEN) {
         res = -EINVAL;
         goto exit;
     }
     timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
     res = tipc_wait_for_accept(sock, timeo);
     if (res)
         goto exit;
 
     buf = skb_peek(&sk->sk_receive_queue);
 
     res = tipc_sk_create(sock_net(sock->sk), new_sock, 0, kern);
     if (res)
         goto exit;
     security_sk_clone(sock->sk, new_sock->sk);
 
     new_sk = new_sock->sk;
     new_tsock = tipc_sk(new_sk);
     msg = buf_msg(buf);
 
     /* we lock on new_sk; but lockdep sees the lock on sk */
     lock_sock_nested(new_sk, SINGLE_DEPTH_NESTING);
 
     /*
      * Reject any stray messages received by new socket
      * before the socket lock was taken (very, very unlikely)
      */
     tsk_rej_rx_queue(new_sk, TIPC_ERR_NO_PORT);
 
     /* Connect new socket to it's peer */
     tipc_sk_finish_conn(new_tsock, msg_origport(msg), msg_orignode(msg));
 
     tsk_set_importance(new_sk, msg_importance(msg));
     if (msg_named(msg)) {
         new_tsock->conn_addrtype = TIPC_SERVICE_ADDR;
         msg_set_nametype(&new_tsock->phdr, msg_nametype(msg));
         msg_set_nameinst(&new_tsock->phdr, msg_nameinst(msg));
     }
 
     /*
      * Respond to 'SYN-' by discarding it & returning 'ACK'.
      * Respond to 'SYN+' by queuing it on new socket & returning 'ACK'.
      */
     if (!msg_data_sz(msg)) {
         tsk_advance_rx_queue(sk);
     } else {
         __skb_dequeue(&sk->sk_receive_queue);
         __skb_queue_head(&new_sk->sk_receive_queue, buf);
         skb_set_owner_r(buf, new_sk);
     }
     __tipc_sendstream(new_sock, &m, 0);
     release_sock(new_sk);
 exit:
     release_sock(sk);
     return res;
 }
 
 /**
  * tipc_shutdown - shutdown socket connection
  * @sock: socket structure
  * @how: direction to close (must be SHUT_RDWR)
  *
  * Terminates connection (if necessary), then purges socket's receive queue.
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_shutdown(struct socket *sock, int how)
 {
     struct sock *sk = sock->sk;
     int res;
 
     if (how != SHUT_RDWR)
         return -EINVAL;
 
     lock_sock(sk);
 
     trace_tipc_sk_shutdown(sk, NULL, TIPC_DUMP_ALL, " ");
     __tipc_shutdown(sock, TIPC_CONN_SHUTDOWN);
     sk->sk_shutdown = SHUTDOWN_MASK;
 
     if (sk->sk_state == TIPC_DISCONNECTING) {
         /* Discard any unreceived messages */
         __skb_queue_purge(&sk->sk_receive_queue);
 
         res = 0;
     } else {
         res = -ENOTCONN;
     }
     /* Wake up anyone sleeping in poll. */
     sk->sk_state_change(sk);
 
     release_sock(sk);
     return res;
 }
 
 static void tipc_sk_check_probing_state(struct sock *sk,
                     struct sk_buff_head *list)
 {
     struct tipc_sock *tsk = tipc_sk(sk);
     u32 pnode = tsk_peer_node(tsk);
     u32 pport = tsk_peer_port(tsk);
     u32 self = tsk_own_node(tsk);
     u32 oport = tsk->portid;
     struct sk_buff *skb;
 
     if (tsk->probe_unacked) {
         tipc_set_sk_state(sk, TIPC_DISCONNECTING);
         sk->sk_err = ECONNABORTED;
         tipc_node_remove_conn(sock_net(sk), pnode, pport);
         sk->sk_state_change(sk);
         return;
     }
     /* Prepare new probe */
     skb = tipc_msg_create(CONN_MANAGER, CONN_PROBE, INT_H_SIZE, 0,
                   pnode, self, pport, oport, TIPC_OK);
     if (skb)
         __skb_queue_tail(list, skb);
     tsk->probe_unacked = true;
     sk_reset_timer(sk, &sk->sk_timer, jiffies + CONN_PROBING_INTV);
 }
 
 static void tipc_sk_retry_connect(struct sock *sk, struct sk_buff_head *list)
 {
     struct tipc_sock *tsk = tipc_sk(sk);
 
     /* Try again later if dest link is congested */
     if (tsk->cong_link_cnt) {
         sk_reset_timer(sk, &sk->sk_timer,
                    jiffies + msecs_to_jiffies(100));
         return;
     }
     /* Prepare SYN for retransmit */
     tipc_msg_skb_clone(&sk->sk_write_queue, list);
 }
 
 static void tipc_sk_timeout(struct timer_list *t)
 {
     struct sock *sk = from_timer(sk, t, sk_timer);
     struct tipc_sock *tsk = tipc_sk(sk);
     u32 pnode = tsk_peer_node(tsk);
     struct sk_buff_head list;
     int rc = 0;
 
     __skb_queue_head_init(&list);
     bh_lock_sock(sk);
 
     /* Try again later if socket is busy */
     if (sock_owned_by_user(sk)) {
         sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ / 20);
         bh_unlock_sock(sk);
         sock_put(sk);
         return;
     }
 
     if (sk->sk_state == TIPC_ESTABLISHED)
         tipc_sk_check_probing_state(sk, &list);
     else if (sk->sk_state == TIPC_CONNECTING)
         tipc_sk_retry_connect(sk, &list);
 
     bh_unlock_sock(sk);
 
     if (!skb_queue_empty(&list))
         rc = tipc_node_xmit(sock_net(sk), &list, pnode, tsk->portid);
 
     /* SYN messages may cause link congestion */
     if (rc == -ELINKCONG) {
         tipc_dest_push(&tsk->cong_links, pnode, 0);
         tsk->cong_link_cnt = 1;
     }
     sock_put(sk);
 }
 
 static int tipc_sk_publish(struct tipc_sock *tsk, struct tipc_uaddr *ua)
 {
     struct sock *sk = &tsk->sk;
     struct net *net = sock_net(sk);
     struct tipc_socket_addr skaddr;
     struct publication *p;
     u32 key;
 
     if (tipc_sk_connected(sk))
         return -EINVAL;
     key = tsk->portid + tsk->pub_count + 1;
     if (key == tsk->portid)
         return -EADDRINUSE;
     skaddr.ref = tsk->portid;
     skaddr.node = tipc_own_addr(net);
     p = tipc_nametbl_publish(net, ua, &skaddr, key);
     if (unlikely(!p))
         return -EINVAL;
 
     list_add(&p->binding_sock, &tsk->publications);
     tsk->pub_count++;
     tsk->published = true;
     return 0;
 }
 
 static int tipc_sk_withdraw(struct tipc_sock *tsk, struct tipc_uaddr *ua)
 {
     struct net *net = sock_net(&tsk->sk);
     struct publication *safe, *p;
     struct tipc_uaddr _ua;
     int rc = -EINVAL;
 
     list_for_each_entry_safe(p, safe, &tsk->publications, binding_sock) {
         if (!ua) {
             tipc_uaddr(&_ua, TIPC_SERVICE_RANGE, p->scope,
                    p->sr.type, p->sr.lower, p->sr.upper);
             tipc_nametbl_withdraw(net, &_ua, &p->sk, p->key);
             continue;
         }
         /* Unbind specific publication */
         if (p->scope != ua->scope)
             continue;
         if (p->sr.type != ua->sr.type)
             continue;
         if (p->sr.lower != ua->sr.lower)
             continue;
         if (p->sr.upper != ua->sr.upper)
             break;
         tipc_nametbl_withdraw(net, ua, &p->sk, p->key);
         rc = 0;
         break;
     }
     if (list_empty(&tsk->publications)) {
         tsk->published = 0;
         rc = 0;
     }
     return rc;
 }
 
 /* tipc_sk_reinit: set non-zero address in all existing sockets
  *                 when we go from standalone to network mode.
  */
 void tipc_sk_reinit(struct net *net)
 {
     struct tipc_net *tn = net_generic(net, tipc_net_id);
     struct rhashtable_iter iter;
     struct tipc_sock *tsk;
     struct tipc_msg *msg;
 
     rhashtable_walk_enter(&tn->sk_rht, &iter);
 
     do {
         rhashtable_walk_start(&iter);
 
         while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
             sock_hold(&tsk->sk);
             rhashtable_walk_stop(&iter);
             lock_sock(&tsk->sk);
             msg = &tsk->phdr;
             msg_set_prevnode(msg, tipc_own_addr(net));
             msg_set_orignode(msg, tipc_own_addr(net));
             release_sock(&tsk->sk);
             rhashtable_walk_start(&iter);
             sock_put(&tsk->sk);
         }
 
         rhashtable_walk_stop(&iter);
     } while (tsk == ERR_PTR(-EAGAIN));
 
     rhashtable_walk_exit(&iter);
 }
 
 static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid)
 {
     struct tipc_net *tn = net_generic(net, tipc_net_id);
     struct tipc_sock *tsk;
 
     rcu_read_lock();
     tsk = rhashtable_lookup(&tn->sk_rht, &portid, tsk_rht_params);
     if (tsk)
         sock_hold(&tsk->sk);
     rcu_read_unlock();
 
     return tsk;
 }
 
 static int tipc_sk_insert(struct tipc_sock *tsk)
 {
     struct sock *sk = &tsk->sk;
     struct net *net = sock_net(sk);
     struct tipc_net *tn = net_generic(net, tipc_net_id);
     u32 remaining = (TIPC_MAX_PORT - TIPC_MIN_PORT) + 1;
     u32 portid = prandom_u32() % remaining + TIPC_MIN_PORT;
 
     while (remaining--) {
         portid++;
         if ((portid < TIPC_MIN_PORT) || (portid > TIPC_MAX_PORT))
             portid = TIPC_MIN_PORT;
         tsk->portid = portid;
         sock_hold(&tsk->sk);
         if (!rhashtable_lookup_insert_fast(&tn->sk_rht, &tsk->node,
                            tsk_rht_params))
             return 0;
         sock_put(&tsk->sk);
     }
 
     return -1;
 }
 
 static void tipc_sk_remove(struct tipc_sock *tsk)
 {
     struct sock *sk = &tsk->sk;
     struct tipc_net *tn = net_generic(sock_net(sk), tipc_net_id);
 
     if (!rhashtable_remove_fast(&tn->sk_rht, &tsk->node, tsk_rht_params)) {
         WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
         __sock_put(sk);
     }
 }
 
 static const struct rhashtable_params tsk_rht_params = {
     .nelem_hint = 192,
     .head_offset = offsetof(struct tipc_sock, node),
     .key_offset = offsetof(struct tipc_sock, portid),
     .key_len = sizeof(u32), /* portid */
     .max_size = 1048576,
     .min_size = 256,
     .automatic_shrinking = true,
 };
 
 int tipc_sk_rht_init(struct net *net)
 {
     struct tipc_net *tn = net_generic(net, tipc_net_id);
 
     return rhashtable_init(&tn->sk_rht, &tsk_rht_params);
 }
 
 void tipc_sk_rht_destroy(struct net *net)
 {
     struct tipc_net *tn = net_generic(net, tipc_net_id);
 
     /* Wait for socket readers to complete */
     synchronize_net();
 
     rhashtable_destroy(&tn->sk_rht);
 }
 
 static int tipc_sk_join(struct tipc_sock *tsk, struct tipc_group_req *mreq)
 {
     struct net *net = sock_net(&tsk->sk);
     struct tipc_group *grp = tsk->group;
     struct tipc_msg *hdr = &tsk->phdr;
     struct tipc_uaddr ua;
     int rc;
 
     if (mreq->type < TIPC_RESERVED_TYPES)
         return -EACCES;
     if (mreq->scope > TIPC_NODE_SCOPE)
         return -EINVAL;
     if (mreq->scope != TIPC_NODE_SCOPE)
         mreq->scope = TIPC_CLUSTER_SCOPE;
     if (grp)
         return -EACCES;
     grp = tipc_group_create(net, tsk->portid, mreq, &tsk->group_is_open);
     if (!grp)
         return -ENOMEM;
     tsk->group = grp;
     msg_set_lookup_scope(hdr, mreq->scope);
     msg_set_nametype(hdr, mreq->type);
     msg_set_dest_droppable(hdr, true);
     tipc_uaddr(&ua, TIPC_SERVICE_RANGE, mreq->scope,
            mreq->type, mreq->instance, mreq->instance);
     tipc_nametbl_build_group(net, grp, &ua);
     rc = tipc_sk_publish(tsk, &ua);
     if (rc) {
         tipc_group_delete(net, grp);
         tsk->group = NULL;
         return rc;
     }
     /* Eliminate any risk that a broadcast overtakes sent JOINs */
     tsk->mc_method.rcast = true;
     tsk->mc_method.mandatory = true;
     tipc_group_join(net, grp, &tsk->sk.sk_rcvbuf);
     return rc;
 }
 
 static int tipc_sk_leave(struct tipc_sock *tsk)
 {
     struct net *net = sock_net(&tsk->sk);
     struct tipc_group *grp = tsk->group;
     struct tipc_uaddr ua;
     int scope;
 
     if (!grp)
         return -EINVAL;
     ua.addrtype = TIPC_SERVICE_RANGE;
     tipc_group_self(grp, &ua.sr, &scope);
     ua.scope = scope;
     tipc_group_delete(net, grp);
     tsk->group = NULL;
     tipc_sk_withdraw(tsk, &ua);
     return 0;
 }
 
 /**
  * tipc_setsockopt - set socket option
  * @sock: socket structure
  * @lvl: option level
  * @opt: option identifier
  * @ov: pointer to new option value
  * @ol: length of option value
  *
  * For stream sockets only, accepts and ignores all IPPROTO_TCP options
  * (to ease compatibility).
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_setsockopt(struct socket *sock, int lvl, int opt,
                sockptr_t ov, unsigned int ol)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_group_req mreq;
     u32 value = 0;
     int res = 0;
 
     if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
         return 0;
     if (lvl != SOL_TIPC)
         return -ENOPROTOOPT;
 
     switch (opt) {
     case TIPC_IMPORTANCE:
     case TIPC_SRC_DROPPABLE:
     case TIPC_DEST_DROPPABLE:
     case TIPC_CONN_TIMEOUT:
     case TIPC_NODELAY:
         if (ol < sizeof(value))
             return -EINVAL;
         if (copy_from_sockptr(&value, ov, sizeof(u32)))
             return -EFAULT;
         break;
     case TIPC_GROUP_JOIN:
         if (ol < sizeof(mreq))
             return -EINVAL;
         if (copy_from_sockptr(&mreq, ov, sizeof(mreq)))
             return -EFAULT;
         break;
     default:
         if (!sockptr_is_null(ov) || ol)
             return -EINVAL;
     }
 
     lock_sock(sk);
 
     switch (opt) {
     case TIPC_IMPORTANCE:
         res = tsk_set_importance(sk, value);
         break;
     case TIPC_SRC_DROPPABLE:
         if (sock->type != SOCK_STREAM)
             tsk_set_unreliable(tsk, value);
         else
             res = -ENOPROTOOPT;
         break;
     case TIPC_DEST_DROPPABLE:
         tsk_set_unreturnable(tsk, value);
         break;
     case TIPC_CONN_TIMEOUT:
         tipc_sk(sk)->conn_timeout = value;
         break;
     case TIPC_MCAST_BROADCAST:
         tsk->mc_method.rcast = false;
         tsk->mc_method.mandatory = true;
         break;
     case TIPC_MCAST_REPLICAST:
         tsk->mc_method.rcast = true;
         tsk->mc_method.mandatory = true;
         break;
     case TIPC_GROUP_JOIN:
         res = tipc_sk_join(tsk, &mreq);
         break;
     case TIPC_GROUP_LEAVE:
         res = tipc_sk_leave(tsk);
         break;
     case TIPC_NODELAY:
         tsk->nodelay = !!value;
         tsk_set_nagle(tsk);
         break;
     default:
         res = -EINVAL;
     }
 
     release_sock(sk);
 
     return res;
 }
 
 /**
  * tipc_getsockopt - get socket option
  * @sock: socket structure
  * @lvl: option level
  * @opt: option identifier
  * @ov: receptacle for option value
  * @ol: receptacle for length of option value
  *
  * For stream sockets only, returns 0 length result for all IPPROTO_TCP options
  * (to ease compatibility).
  *
  * Return: 0 on success, errno otherwise
  */
 static int tipc_getsockopt(struct socket *sock, int lvl, int opt,
                char __user *ov, int __user *ol)
 {
     struct sock *sk = sock->sk;
     struct tipc_sock *tsk = tipc_sk(sk);
     struct tipc_service_range seq;
     int len, scope;
     u32 value;
     int res;
 
     if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
         return put_user(0, ol);
     if (lvl != SOL_TIPC)
         return -ENOPROTOOPT;
     res = get_user(len, ol);
     if (res)
         return res;
 
     lock_sock(sk);
 
     switch (opt) {
     case TIPC_IMPORTANCE:
         value = tsk_importance(tsk);
         break;
     case TIPC_SRC_DROPPABLE:
         value = tsk_unreliable(tsk);
         break;
     case TIPC_DEST_DROPPABLE:
         value = tsk_unreturnable(tsk);
         break;
     case TIPC_CONN_TIMEOUT:
         value = tsk->conn_timeout;
         /* no need to set "res", since already 0 at this point */
         break;
     case TIPC_NODE_RECVQ_DEPTH:
         value = 0; /* was tipc_queue_size, now obsolete */
         break;
     case TIPC_SOCK_RECVQ_DEPTH:
         value = skb_queue_len(&sk->sk_receive_queue);
         break;
     case TIPC_SOCK_RECVQ_USED:
         value = sk_rmem_alloc_get(sk);
         break;
     case TIPC_GROUP_JOIN:
         seq.type = 0;
         if (tsk->group)
             tipc_group_self(tsk->group, &seq, &scope);
         value = seq.type;
         break;
     default:
         res = -EINVAL;
     }
 
     release_sock(sk);
 
     if (res)
         return res; /* "get" failed */
 
     if (len < sizeof(value))
         return -EINVAL;
 
     if (copy_to_user(ov, &value, sizeof(value)))
         return -EFAULT;
 
     return put_user(sizeof(value), ol);
 }
 
 static int tipc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 {
     struct net *net = sock_net(sock->sk);
     struct tipc_sioc_nodeid_req nr = {0};
     struct tipc_sioc_ln_req lnr;
     void __user *argp = (void __user *)arg;
 
     switch (cmd) {
     case SIOCGETLINKNAME:
         if (copy_from_user(&lnr, argp, sizeof(lnr)))
             return -EFAULT;
         if (!tipc_node_get_linkname(net,
                         lnr.bearer_id & 0xffff, lnr.peer,
                         lnr.linkname, TIPC_MAX_LINK_NAME)) {
             if (copy_to_user(argp, &lnr, sizeof(lnr)))
                 return -EFAULT;
             return 0;
         }
         return -EADDRNOTAVAIL;
     case SIOCGETNODEID:
         if (copy_from_user(&nr, argp, sizeof(nr)))
             return -EFAULT;
         if (!tipc_node_get_id(net, nr.peer, nr.node_id))
             return -EADDRNOTAVAIL;
         if (copy_to_user(argp, &nr, sizeof(nr)))
             return -EFAULT;
         return 0;
     default:
         return -ENOIOCTLCMD;
     }
 }
 
 static int tipc_socketpair(struct socket *sock1, struct socket *sock2)
 {
     struct tipc_sock *tsk2 = tipc_sk(sock2->sk);
     struct tipc_sock *tsk1 = tipc_sk(sock1->sk);
     u32 onode = tipc_own_addr(sock_net(sock1->sk));
 
     tsk1->peer.family = AF_TIPC;
     tsk1->peer.addrtype = TIPC_SOCKET_ADDR;
     tsk1->peer.scope = TIPC_NODE_SCOPE;
     tsk1->peer.addr.id.ref = tsk2->portid;
     tsk1->peer.addr.id.node = onode;
     tsk2->peer.family = AF_TIPC;
     tsk2->peer.addrtype = TIPC_SOCKET_ADDR;
     tsk2->peer.scope = TIPC_NODE_SCOPE;
     tsk2->peer.addr.id.ref = tsk1->portid;
     tsk2->peer.addr.id.node = onode;
 
     tipc_sk_finish_conn(tsk1, tsk2->portid, onode);
     tipc_sk_finish_conn(tsk2, tsk1->portid, onode);
     return 0;
 }
 
 /* Protocol switches for the various types of TIPC sockets */
 
 static const struct proto_ops msg_ops = {
     .owner      = THIS_MODULE,
     .family     = AF_TIPC,
     .release    = tipc_release,
     .bind       = tipc_bind,
     .connect    = tipc_connect,
     .socketpair = tipc_socketpair,
     .accept     = sock_no_accept,
     .getname    = tipc_getname,
     .poll       = tipc_poll,
     .ioctl      = tipc_ioctl,
     .listen     = sock_no_listen,
     .shutdown   = tipc_shutdown,
     .setsockopt = tipc_setsockopt,
     .getsockopt = tipc_getsockopt,
     .sendmsg    = tipc_sendmsg,
     .recvmsg    = tipc_recvmsg,
     .mmap       = sock_no_mmap,
     .sendpage   = sock_no_sendpage
 };
 
 static const struct proto_ops packet_ops = {
     .owner      = THIS_MODULE,
     .family     = AF_TIPC,
     .release    = tipc_release,
     .bind       = tipc_bind,
     .connect    = tipc_connect,
     .socketpair = tipc_socketpair,
     .accept     = tipc_accept,
     .getname    = tipc_getname,
     .poll       = tipc_poll,
     .ioctl      = tipc_ioctl,
     .listen     = tipc_listen,
     .shutdown   = tipc_shutdown,
     .setsockopt = tipc_setsockopt,
     .getsockopt = tipc_getsockopt,
     .sendmsg    = tipc_send_packet,
     .recvmsg    = tipc_recvmsg,
     .mmap       = sock_no_mmap,
     .sendpage   = sock_no_sendpage
 };
 
 static const struct proto_ops stream_ops = {
     .owner      = THIS_MODULE,
     .family     = AF_TIPC,
     .release    = tipc_release,
     .bind       = tipc_bind,
     .connect    = tipc_connect,
     .socketpair = tipc_socketpair,
     .accept     = tipc_accept,
     .getname    = tipc_getname,
     .poll       = tipc_poll,
     .ioctl      = tipc_ioctl,
     .listen     = tipc_listen,
     .shutdown   = tipc_shutdown,
     .setsockopt = tipc_setsockopt,
     .getsockopt = tipc_getsockopt,
     .sendmsg    = tipc_sendstream,
     .recvmsg    = tipc_recvstream,
     .mmap       = sock_no_mmap,
     .sendpage   = sock_no_sendpage
 };
 
 static const struct net_proto_family tipc_family_ops = {
     .owner      = THIS_MODULE,
     .family     = AF_TIPC,
     .create     = tipc_sk_create
 };
 
 static struct proto tipc_proto = {
     .name       = "TIPC",
     .owner      = THIS_MODULE,
     .obj_size   = sizeof(struct tipc_sock),
     .sysctl_rmem    = sysctl_tipc_rmem
 };
 
 /**
  * tipc_socket_init - initialize TIPC socket interface
  *
  * Return: 0 on success, errno otherwise
  */
 int tipc_socket_init(void)
 {
     int res;
 
     res = proto_register(&tipc_proto, 1);
     if (res) {
         pr_err("Failed to register TIPC protocol type\n");
         goto out;
     }
 
     res = sock_register(&tipc_family_ops);
     if (res) {
         pr_err("Failed to register TIPC socket type\n");
         proto_unregister(&tipc_proto);
         goto out;
     }
  out:
     return res;
 }
 
 /**
  * tipc_socket_stop - stop TIPC socket interface
  */
 void tipc_socket_stop(void)
 {
     sock_unregister(tipc_family_ops.family);
     proto_unregister(&tipc_proto);
 }
 
 /* Caller should hold socket lock for the passed tipc socket. */
 static int __tipc_nl_add_sk_con(struct sk_buff *skb, struct tipc_sock *tsk)
 {
     u32 peer_node, peer_port;
     u32 conn_type, conn_instance;
     struct nlattr *nest;
 
     peer_node = tsk_peer_node(tsk);
     peer_port = tsk_peer_port(tsk);
     conn_type = msg_nametype(&tsk->phdr);
     conn_instance = msg_nameinst(&tsk->phdr);
     nest = nla_nest_start_noflag(skb, TIPC_NLA_SOCK_CON);
     if (!nest)
         return -EMSGSIZE;
 
     if (nla_put_u32(skb, TIPC_NLA_CON_NODE, peer_node))
         goto msg_full;
     if (nla_put_u32(skb, TIPC_NLA_CON_SOCK, peer_port))
         goto msg_full;
 
     if (tsk->conn_addrtype != 0) {
         if (nla_put_flag(skb, TIPC_NLA_CON_FLAG))
             goto msg_full;
         if (nla_put_u32(skb, TIPC_NLA_CON_TYPE, conn_type))
             goto msg_full;
         if (nla_put_u32(skb, TIPC_NLA_CON_INST, conn_instance))
             goto msg_full;
     }
     nla_nest_end(skb, nest);
 
     return 0;
 
 msg_full:
     nla_nest_cancel(skb, nest);
 
     return -EMSGSIZE;
 }
 
 static int __tipc_nl_add_sk_info(struct sk_buff *skb, struct tipc_sock
               *tsk)
 {
     struct net *net = sock_net(skb->sk);
     struct sock *sk = &tsk->sk;
 
     if (nla_put_u32(skb, TIPC_NLA_SOCK_REF, tsk->portid) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_ADDR, tipc_own_addr(net)))
         return -EMSGSIZE;
 
     if (tipc_sk_connected(sk)) {
         if (__tipc_nl_add_sk_con(skb, tsk))
             return -EMSGSIZE;
     } else if (!list_empty(&tsk->publications)) {
         if (nla_put_flag(skb, TIPC_NLA_SOCK_HAS_PUBL))
             return -EMSGSIZE;
     }
     return 0;
 }
 
 /* Caller should hold socket lock for the passed tipc socket. */
 static int __tipc_nl_add_sk(struct sk_buff *skb, struct netlink_callback *cb,
                 struct tipc_sock *tsk)
 {
     struct nlattr *attrs;
     void *hdr;
 
     hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
               &tipc_genl_family, NLM_F_MULTI, TIPC_NL_SOCK_GET);
     if (!hdr)
         goto msg_cancel;
 
     attrs = nla_nest_start_noflag(skb, TIPC_NLA_SOCK);
     if (!attrs)
         goto genlmsg_cancel;
 
     if (__tipc_nl_add_sk_info(skb, tsk))
         goto attr_msg_cancel;
 
     nla_nest_end(skb, attrs);
     genlmsg_end(skb, hdr);
 
     return 0;
 
 attr_msg_cancel:
     nla_nest_cancel(skb, attrs);
 genlmsg_cancel:
     genlmsg_cancel(skb, hdr);
 msg_cancel:
     return -EMSGSIZE;
 }
 
 int tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
             int (*skb_handler)(struct sk_buff *skb,
                        struct netlink_callback *cb,
                        struct tipc_sock *tsk))
 {
     struct rhashtable_iter *iter = (void *)cb->args[4];
     struct tipc_sock *tsk;
     int err;
 
     rhashtable_walk_start(iter);
     while ((tsk = rhashtable_walk_next(iter)) != NULL) {
         if (IS_ERR(tsk)) {
             err = PTR_ERR(tsk);
             if (err == -EAGAIN) {
                 err = 0;
                 continue;
             }
             break;
         }
 
         sock_hold(&tsk->sk);
         rhashtable_walk_stop(iter);
         lock_sock(&tsk->sk);
         err = skb_handler(skb, cb, tsk);
         if (err) {
             release_sock(&tsk->sk);
             sock_put(&tsk->sk);
             goto out;
         }
         release_sock(&tsk->sk);
         rhashtable_walk_start(iter);
         sock_put(&tsk->sk);
     }
     rhashtable_walk_stop(iter);
 out:
     return skb->len;
 }
 EXPORT_SYMBOL(tipc_nl_sk_walk);
 
 int tipc_dump_start(struct netlink_callback *cb)
 {
     return __tipc_dump_start(cb, sock_net(cb->skb->sk));
 }
 EXPORT_SYMBOL(tipc_dump_start);
 
 int __tipc_dump_start(struct netlink_callback *cb, struct net *net)
 {
     /* tipc_nl_name_table_dump() uses cb->args[0...3]. */
     struct rhashtable_iter *iter = (void *)cb->args[4];
     struct tipc_net *tn = tipc_net(net);
 
     if (!iter) {
         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
         if (!iter)
             return -ENOMEM;
 
         cb->args[4] = (long)iter;
     }
 
     rhashtable_walk_enter(&tn->sk_rht, iter);
     return 0;
 }
 
 int tipc_dump_done(struct netlink_callback *cb)
 {
     struct rhashtable_iter *hti = (void *)cb->args[4];
 
     rhashtable_walk_exit(hti);
     kfree(hti);
     return 0;
 }
 EXPORT_SYMBOL(tipc_dump_done);
 
 int tipc_sk_fill_sock_diag(struct sk_buff *skb, struct netlink_callback *cb,
                struct tipc_sock *tsk, u32 sk_filter_state,
                u64 (*tipc_diag_gen_cookie)(struct sock *sk))
 {
     struct sock *sk = &tsk->sk;
     struct nlattr *attrs;
     struct nlattr *stat;
 
     /*filter response w.r.t sk_state*/
     if (!(sk_filter_state & (1 << sk->sk_state)))
         return 0;
 
     attrs = nla_nest_start_noflag(skb, TIPC_NLA_SOCK);
     if (!attrs)
         goto msg_cancel;
 
     if (__tipc_nl_add_sk_info(skb, tsk))
         goto attr_msg_cancel;
 
     if (nla_put_u32(skb, TIPC_NLA_SOCK_TYPE, (u32)sk->sk_type) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_TIPC_STATE, (u32)sk->sk_state) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_INO, sock_i_ino(sk)) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_UID,
             from_kuid_munged(sk_user_ns(NETLINK_CB(cb->skb).sk),
                      sock_i_uid(sk))) ||
         nla_put_u64_64bit(skb, TIPC_NLA_SOCK_COOKIE,
                   tipc_diag_gen_cookie(sk),
                   TIPC_NLA_SOCK_PAD))
         goto attr_msg_cancel;
 
     stat = nla_nest_start_noflag(skb, TIPC_NLA_SOCK_STAT);
     if (!stat)
         goto attr_msg_cancel;
 
     if (nla_put_u32(skb, TIPC_NLA_SOCK_STAT_RCVQ,
             skb_queue_len(&sk->sk_receive_queue)) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_STAT_SENDQ,
             skb_queue_len(&sk->sk_write_queue)) ||
         nla_put_u32(skb, TIPC_NLA_SOCK_STAT_DROP,
             atomic_read(&sk->sk_drops)))
         goto stat_msg_cancel;
 
     if (tsk->cong_link_cnt &&
         nla_put_flag(skb, TIPC_NLA_SOCK_STAT_LINK_CONG))
         goto stat_msg_cancel;
 
     if (tsk_conn_cong(tsk) &&
         nla_put_flag(skb, TIPC_NLA_SOCK_STAT_CONN_CONG))
         goto stat_msg_cancel;
 
     nla_nest_end(skb, stat);
 
     if (tsk->group)
         if (tipc_group_fill_sock_diag(tsk->group, skb))
             goto stat_msg_cancel;
 
     nla_nest_end(skb, attrs);
 
     return 0;
 
 stat_msg_cancel:
     nla_nest_cancel(skb, stat);
 attr_msg_cancel:
     nla_nest_cancel(skb, attrs);
 msg_cancel:
     return -EMSGSIZE;
 }
 EXPORT_SYMBOL(tipc_sk_fill_sock_diag);
 
 int tipc_nl_sk_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
     return tipc_nl_sk_walk(skb, cb, __tipc_nl_add_sk);
 }
 
 /* Caller should hold socket lock for the passed tipc socket. */
 static int __tipc_nl_add_sk_publ(struct sk_buff *skb,
                  struct netlink_callback *cb,
                  struct publication *publ)
 {
     void *hdr;
     struct nlattr *attrs;
 
     hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
               &tipc_genl_family, NLM_F_MULTI, TIPC_NL_PUBL_GET);
     if (!hdr)
         goto msg_cancel;
 
     attrs = nla_nest_start_noflag(skb, TIPC_NLA_PUBL);
     if (!attrs)
         goto genlmsg_cancel;
 
     if (nla_put_u32(skb, TIPC_NLA_PUBL_KEY, publ->key))
         goto attr_msg_cancel;
     if (nla_put_u32(skb, TIPC_NLA_PUBL_TYPE, publ->sr.type))
         goto attr_msg_cancel;
     if (nla_put_u32(skb, TIPC_NLA_PUBL_LOWER, publ->sr.lower))
         goto attr_msg_cancel;
     if (nla_put_u32(skb, TIPC_NLA_PUBL_UPPER, publ->sr.upper))
         goto attr_msg_cancel;
 
     nla_nest_end(skb, attrs);
     genlmsg_end(skb, hdr);
 
     return 0;
 
 attr_msg_cancel:
     nla_nest_cancel(skb, attrs);
 genlmsg_cancel:
     genlmsg_cancel(skb, hdr);
 msg_cancel:
     return -EMSGSIZE;
 }
 
 /* Caller should hold socket lock for the passed tipc socket. */
 static int __tipc_nl_list_sk_publ(struct sk_buff *skb,
                   struct netlink_callback *cb,
                   struct tipc_sock *tsk, u32 *last_publ)
 {
     int err;
     struct publication *p;
 
     if (*last_publ) {
         list_for_each_entry(p, &tsk->publications, binding_sock) {
             if (p->key == *last_publ)
                 break;
         }
         if (list_entry_is_head(p, &tsk->publications, binding_sock)) {
             /* We never set seq or call nl_dump_check_consistent()
              * this means that setting prev_seq here will cause the
              * consistence check to fail in the netlink callback
              * handler. Resulting in the last NLMSG_DONE message
              * having the NLM_F_DUMP_INTR flag set.
              */
             cb->prev_seq = 1;
             *last_publ = 0;
             return -EPIPE;
         }
     } else {
         p = list_first_entry(&tsk->publications, struct publication,
                      binding_sock);
     }
 
     list_for_each_entry_from(p, &tsk->publications, binding_sock) {
         err = __tipc_nl_add_sk_publ(skb, cb, p);
         if (err) {
             *last_publ = p->key;
             return err;
         }
     }
     *last_publ = 0;
 
     return 0;
 }
 
 int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
     int err;
     u32 tsk_portid = cb->args[0];
     u32 last_publ = cb->args[1];
     u32 done = cb->args[2];
     struct net *net = sock_net(skb->sk);
     struct tipc_sock *tsk;
 
     if (!tsk_portid) {
         struct nlattr **attrs = genl_dumpit_info(cb)->attrs;
         struct nlattr *sock[TIPC_NLA_SOCK_MAX + 1];
 
         if (!attrs[TIPC_NLA_SOCK])
             return -EINVAL;
 
         err = nla_parse_nested_deprecated(sock, TIPC_NLA_SOCK_MAX,
                           attrs[TIPC_NLA_SOCK],
                           tipc_nl_sock_policy, NULL);
         if (err)
             return err;
 
         if (!sock[TIPC_NLA_SOCK_REF])
             return -EINVAL;
 
         tsk_portid = nla_get_u32(sock[TIPC_NLA_SOCK_REF]);
     }
 
     if (done)
         return 0;
 
     tsk = tipc_sk_lookup(net, tsk_portid);
     if (!tsk)
         return -EINVAL;
 
     lock_sock(&tsk->sk);
     err = __tipc_nl_list_sk_publ(skb, cb, tsk, &last_publ);
     if (!err)
         done = 1;
     release_sock(&tsk->sk);
     sock_put(&tsk->sk);
 
     cb->args[0] = tsk_portid;
     cb->args[1] = last_publ;
     cb->args[2] = done;
 
     return skb->len;
 }
 
 /**
  * tipc_sk_filtering - check if a socket should be traced
  * @sk: the socket to be examined
  *
  * @sysctl_tipc_sk_filter is used as the socket tuple for filtering:
  * (portid, sock type, name type, name lower, name upper)
  *
  * Return: true if the socket meets the socket tuple data
  * (value 0 = 'any') or when there is no tuple set (all = 0),
  * otherwise false
  */
 bool tipc_sk_filtering(struct sock *sk)
 {
     struct tipc_sock *tsk;
     struct publication *p;
     u32 _port, _sktype, _type, _lower, _upper;
     u32 type = 0, lower = 0, upper = 0;
 
     if (!sk)
         return true;
 
     tsk = tipc_sk(sk);
 
     _port = sysctl_tipc_sk_filter[0];
     _sktype = sysctl_tipc_sk_filter[1];
     _type = sysctl_tipc_sk_filter[2];
     _lower = sysctl_tipc_sk_filter[3];
     _upper = sysctl_tipc_sk_filter[4];
 
     if (!_port && !_sktype && !_type && !_lower && !_upper)
         return true;
 
     if (_port)
         return (_port == tsk->portid);
 
     if (_sktype && _sktype != sk->sk_type)
         return false;
 
     if (tsk->published) {
         p = list_first_entry_or_null(&tsk->publications,
                          struct publication, binding_sock);
         if (p) {
             type = p->sr.type;
             lower = p->sr.lower;
             upper = p->sr.upper;
         }
     }
 
     if (!tipc_sk_type_connectionless(sk)) {
         type = msg_nametype(&tsk->phdr);
         lower = msg_nameinst(&tsk->phdr);
         upper = lower;
     }
 
     if ((_type && _type != type) || (_lower && _lower != lower) ||
         (_upper && _upper != upper))
         return false;
 
     return true;
 }
 
 u32 tipc_sock_get_portid(struct sock *sk)
 {
     return (sk) ? (tipc_sk(sk))->portid : 0;
 }
 
 /**
  * tipc_sk_overlimit1 - check if socket rx queue is about to be overloaded,
  *          both the rcv and backlog queues are considered
  * @sk: tipc sk to be checked
  * @skb: tipc msg to be checked
  *
  * Return: true if the socket rx queue allocation is > 90%, otherwise false
  */
 
 bool tipc_sk_overlimit1(struct sock *sk, struct sk_buff *skb)
 {
     atomic_t *dcnt = &tipc_sk(sk)->dupl_rcvcnt;
     unsigned int lim = rcvbuf_limit(sk, skb) + atomic_read(dcnt);
     unsigned int qsize = sk->sk_backlog.len + sk_rmem_alloc_get(sk);
 
     return (qsize > lim * 90 / 100);
 }
 
 /**
  * tipc_sk_overlimit2 - check if socket rx queue is about to be overloaded,
  *          only the rcv queue is considered
  * @sk: tipc sk to be checked
  * @skb: tipc msg to be checked
  *
  * Return: true if the socket rx queue allocation is > 90%, otherwise false
  */
 
 bool tipc_sk_overlimit2(struct sock *sk, struct sk_buff *skb)
 {
     unsigned int lim = rcvbuf_limit(sk, skb);
     unsigned int qsize = sk_rmem_alloc_get(sk);
 
     return (qsize > lim * 90 / 100);
 }
 
 /**
  * tipc_sk_dump - dump TIPC socket
  * @sk: tipc sk to be dumped
  * @dqueues: bitmask to decide if any socket queue to be dumped?
  *           - TIPC_DUMP_NONE: don't dump socket queues
  *           - TIPC_DUMP_SK_SNDQ: dump socket send queue
  *           - TIPC_DUMP_SK_RCVQ: dump socket rcv queue
  *           - TIPC_DUMP_SK_BKLGQ: dump socket backlog queue
  *           - TIPC_DUMP_ALL: dump all the socket queues above
  * @buf: returned buffer of dump data in format
  */
 int tipc_sk_dump(struct sock *sk, u16 dqueues, char *buf)
 {
     int i = 0;
     size_t sz = (dqueues) ? SK_LMAX : SK_LMIN;
     u32 conn_type, conn_instance;
     struct tipc_sock *tsk;
     struct publication *p;
     bool tsk_connected;
 
     if (!sk) {
         i += scnprintf(buf, sz, "sk data: (null)\n");
         return i;
     }
 
     tsk = tipc_sk(sk);
     tsk_connected = !tipc_sk_type_connectionless(sk);
 
     i += scnprintf(buf, sz, "sk data: %u", sk->sk_type);
     i += scnprintf(buf + i, sz - i, " %d", sk->sk_state);
     i += scnprintf(buf + i, sz - i, " %x", tsk_own_node(tsk));
     i += scnprintf(buf + i, sz - i, " %u", tsk->portid);
     i += scnprintf(buf + i, sz - i, " | %u", tsk_connected);
     if (tsk_connected) {
         i += scnprintf(buf + i, sz - i, " %x", tsk_peer_node(tsk));
         i += scnprintf(buf + i, sz - i, " %u", tsk_peer_port(tsk));
         conn_type = msg_nametype(&tsk->phdr);
         conn_instance = msg_nameinst(&tsk->phdr);
         i += scnprintf(buf + i, sz - i, " %u", conn_type);
         i += scnprintf(buf + i, sz - i, " %u", conn_instance);
     }
     i += scnprintf(buf + i, sz - i, " | %u", tsk->published);
     if (tsk->published) {
         p = list_first_entry_or_null(&tsk->publications,
                          struct publication, binding_sock);
         i += scnprintf(buf + i, sz - i, " %u", (p) ? p->sr.type : 0);
         i += scnprintf(buf + i, sz - i, " %u", (p) ? p->sr.lower : 0);
         i += scnprintf(buf + i, sz - i, " %u", (p) ? p->sr.upper : 0);
     }
     i += scnprintf(buf + i, sz - i, " | %u", tsk->snd_win);
     i += scnprintf(buf + i, sz - i, " %u", tsk->rcv_win);
     i += scnprintf(buf + i, sz - i, " %u", tsk->max_pkt);
     i += scnprintf(buf + i, sz - i, " %x", tsk->peer_caps);
     i += scnprintf(buf + i, sz - i, " %u", tsk->cong_link_cnt);
     i += scnprintf(buf + i, sz - i, " %u", tsk->snt_unacked);
     i += scnprintf(buf + i, sz - i, " %u", tsk->rcv_unacked);
     i += scnprintf(buf + i, sz - i, " %u", atomic_read(&tsk->dupl_rcvcnt));
     i += scnprintf(buf + i, sz - i, " %u", sk->sk_shutdown);
     i += scnprintf(buf + i, sz - i, " | %d", sk_wmem_alloc_get(sk));
     i += scnprintf(buf + i, sz - i, " %d", sk->sk_sndbuf);
     i += scnprintf(buf + i, sz - i, " | %d", sk_rmem_alloc_get(sk));
     i += scnprintf(buf + i, sz - i, " %d", sk->sk_rcvbuf);
     i += scnprintf(buf + i, sz - i, " | %d\n", READ_ONCE(sk->sk_backlog.len));
 
     if (dqueues & TIPC_DUMP_SK_SNDQ) {
         i += scnprintf(buf + i, sz - i, "sk_write_queue: ");
         i += tipc_list_dump(&sk->sk_write_queue, false, buf + i);
     }
 
     if (dqueues & TIPC_DUMP_SK_RCVQ) {
         i += scnprintf(buf + i, sz - i, "sk_receive_queue: ");
         i += tipc_list_dump(&sk->sk_receive_queue, false, buf + i);
     }
 
     if (dqueues & TIPC_DUMP_SK_BKLGQ) {
         i += scnprintf(buf + i, sz - i, "sk_backlog:\n  head ");
         i += tipc_skb_dump(sk->sk_backlog.head, false, buf + i);
         if (sk->sk_backlog.tail != sk->sk_backlog.head) {
             i += scnprintf(buf + i, sz - i, "  tail ");
             i += tipc_skb_dump(sk->sk_backlog.tail, false,
                        buf + i);
         }
     }
 
     return i;
 }