net/atm/signaling.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* net/atm/signaling.c - ATM signaling */
0003
0004 /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
0005
0006 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
0007
0008 #include <linux/errno.h>    /* error codes */
0009 #include <linux/kernel.h>   /* printk */
0010 #include <linux/skbuff.h>
0011 #include <linux/wait.h>
0012 #include <linux/sched.h>    /* jiffies and HZ */
0013 #include <linux/atm.h>      /* ATM stuff */
0014 #include <linux/atmsap.h>
0015 #include <linux/atmsvc.h>
0016 #include <linux/atmdev.h>
0017 #include <linux/bitops.h>
0018 #include <linux/slab.h>
0019
0020 #include "resources.h"
0021 #include "signaling.h"
0022
0023 struct atm_vcc *sigd = NULL;
0024
0025 static void sigd_put_skb(struct sk_buff *skb)
0026 {
0027     if (!sigd) {
0028         pr_debug("atmsvc: no signaling daemon\n");
0029         kfree_skb(skb);
0030         return;
0031     }
0032     atm_force_charge(sigd, skb->truesize);
0033     skb_queue_tail(&sk_atm(sigd)->sk_receive_queue, skb);
0034     sk_atm(sigd)->sk_data_ready(sk_atm(sigd));
0035 }
0036
0037 static void modify_qos(struct atm_vcc *vcc, struct atmsvc_msg *msg)
0038 {
0039     struct sk_buff *skb;
0040
0041     if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
0042         !test_bit(ATM_VF_READY, &vcc->flags))
0043         return;
0044     msg->type = as_error;
0045     if (!vcc->dev->ops->change_qos)
0046         msg->reply = -EOPNOTSUPP;
0047     else {
0048         /* should lock VCC */
0049         msg->reply = vcc->dev->ops->change_qos(vcc, &msg->qos,
0050                                msg->reply);
0051         if (!msg->reply)
0052             msg->type = as_okay;
0053     }
0054     /*
0055      * Should probably just turn around the old skb. But then, the buffer
0056      * space accounting needs to follow the change too. Maybe later.
0057      */
0058     while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
0059         schedule();
0060     *(struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg)) = *msg;
0061     sigd_put_skb(skb);
0062 }
0063
0064 static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
0065 {
0066     struct atmsvc_msg *msg;
0067     struct atm_vcc *session_vcc;
0068     struct sock *sk;
0069
0070     msg = (struct atmsvc_msg *) skb->data;
0071     WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
0072     vcc = *(struct atm_vcc **) &msg->vcc;
0073     pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
0074     sk = sk_atm(vcc);
0075
0076     switch (msg->type) {
0077     case as_okay:
0078         sk->sk_err = -msg->reply;
0079         clear_bit(ATM_VF_WAITING, &vcc->flags);
0080         if (!*vcc->local.sas_addr.prv && !*vcc->local.sas_addr.pub) {
0081             vcc->local.sas_family = AF_ATMSVC;
0082             memcpy(vcc->local.sas_addr.prv,
0083                    msg->local.sas_addr.prv, ATM_ESA_LEN);
0084             memcpy(vcc->local.sas_addr.pub,
0085                    msg->local.sas_addr.pub, ATM_E164_LEN + 1);
0086         }
0087         session_vcc = vcc->session ? vcc->session : vcc;
0088         if (session_vcc->vpi || session_vcc->vci)
0089             break;
0090         session_vcc->itf = msg->pvc.sap_addr.itf;
0091         session_vcc->vpi = msg->pvc.sap_addr.vpi;
0092         session_vcc->vci = msg->pvc.sap_addr.vci;
0093         if (session_vcc->vpi || session_vcc->vci)
0094             session_vcc->qos = msg->qos;
0095         break;
0096     case as_error:
0097         clear_bit(ATM_VF_REGIS, &vcc->flags);
0098         clear_bit(ATM_VF_READY, &vcc->flags);
0099         sk->sk_err = -msg->reply;
0100         clear_bit(ATM_VF_WAITING, &vcc->flags);
0101         break;
0102     case as_indicate:
0103         vcc = *(struct atm_vcc **)&msg->listen_vcc;
0104         sk = sk_atm(vcc);
0105         pr_debug("as_indicate!!!\n");
0106         lock_sock(sk);
0107         if (sk_acceptq_is_full(sk)) {
0108             sigd_enq(NULL, as_reject, vcc, NULL, NULL);
0109             dev_kfree_skb(skb);
0110             goto as_indicate_complete;
0111         }
0112         sk_acceptq_added(sk);
0113         skb_queue_tail(&sk->sk_receive_queue, skb);
0114         pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
0115         sk->sk_state_change(sk);
0116 as_indicate_complete:
0117         release_sock(sk);
0118         return 0;
0119     case as_close:
0120         set_bit(ATM_VF_RELEASED, &vcc->flags);
0121         vcc_release_async(vcc, msg->reply);
0122         goto out;
0123     case as_modify:
0124         modify_qos(vcc, msg);
0125         break;
0126     case as_addparty:
0127     case as_dropparty:
0128         sk->sk_err_soft = -msg->reply;
0129                     /* < 0 failure, otherwise ep_ref */
0130         clear_bit(ATM_VF_WAITING, &vcc->flags);
0131         break;
0132     default:
0133         pr_alert("bad message type %d\n", (int)msg->type);
0134         return -EINVAL;
0135     }
0136     sk->sk_state_change(sk);
0137 out:
0138     dev_kfree_skb(skb);
0139     return 0;
0140 }
0141
0142 void sigd_enq2(struct atm_vcc *vcc, enum atmsvc_msg_type type,
0143            struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
0144            const struct sockaddr_atmsvc *svc, const struct atm_qos *qos,
0145            int reply)
0146 {
0147     struct sk_buff *skb;
0148     struct atmsvc_msg *msg;
0149     static unsigned int session = 0;
0150
0151     pr_debug("%d (0x%p)\n", (int)type, vcc);
0152     while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
0153         schedule();
0154     msg = skb_put_zero(skb, sizeof(struct atmsvc_msg));
0155     msg->type = type;
0156     *(struct atm_vcc **) &msg->vcc = vcc;
0157     *(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
0158     msg->reply = reply;
0159     if (qos)
0160         msg->qos = *qos;
0161     if (vcc)
0162         msg->sap = vcc->sap;
0163     if (svc)
0164         msg->svc = *svc;
0165     if (vcc)
0166         msg->local = vcc->local;
0167     if (pvc)
0168         msg->pvc = *pvc;
0169     if (vcc) {
0170         if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
0171             msg->session = ++session;
0172             /* every new pmp connect gets the next session number */
0173     }
0174     sigd_put_skb(skb);
0175     if (vcc)
0176         set_bit(ATM_VF_REGIS, &vcc->flags);
0177 }
0178
0179 void sigd_enq(struct atm_vcc *vcc, enum atmsvc_msg_type type,
0180           struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
0181           const struct sockaddr_atmsvc *svc)
0182 {
0183     sigd_enq2(vcc, type, listen_vcc, pvc, svc, vcc ? &vcc->qos : NULL, 0);
0184     /* other ISP applications may use "reply" */
0185 }
0186
0187 static void purge_vcc(struct atm_vcc *vcc)
0188 {
0189     if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
0190         !test_bit(ATM_VF_META, &vcc->flags)) {
0191         set_bit(ATM_VF_RELEASED, &vcc->flags);
0192         clear_bit(ATM_VF_REGIS, &vcc->flags);
0193         vcc_release_async(vcc, -EUNATCH);
0194     }
0195 }
0196
0197 static void sigd_close(struct atm_vcc *vcc)
0198 {
0199     struct sock *s;
0200     int i;
0201
0202     pr_debug("\n");
0203     sigd = NULL;
0204     if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
0205         pr_err("closing with requests pending\n");
0206     skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
0207
0208     read_lock(&vcc_sklist_lock);
0209     for (i = 0; i < VCC_HTABLE_SIZE; ++i) {
0210         struct hlist_head *head = &vcc_hash[i];
0211
0212         sk_for_each(s, head) {
0213             vcc = atm_sk(s);
0214
0215             purge_vcc(vcc);
0216         }
0217     }
0218     read_unlock(&vcc_sklist_lock);
0219 }
0220
0221 static const struct atmdev_ops sigd_dev_ops = {
0222     .close = sigd_close,
0223     .send = sigd_send
0224 };
0225
0226 static struct atm_dev sigd_dev = {
0227     .ops =      &sigd_dev_ops,
0228     .type =     "sig",
0229     .number =   999,
0230     .lock =     __SPIN_LOCK_UNLOCKED(sigd_dev.lock)
0231 };
0232
0233 int sigd_attach(struct atm_vcc *vcc)
0234 {
0235     if (sigd)
0236         return -EADDRINUSE;
0237     pr_debug("\n");
0238     sigd = vcc;
0239     vcc->dev = &sigd_dev;
0240     vcc_insert_socket(sk_atm(vcc));
0241     set_bit(ATM_VF_META, &vcc->flags);
0242     set_bit(ATM_VF_READY, &vcc->flags);
0243     return 0;
0244 }