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0001 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
0002 /* isotp.c - ISO 15765-2 CAN transport protocol for protocol family CAN
0003  *
0004  * This implementation does not provide ISO-TP specific return values to the
0005  * userspace.
0006  *
0007  * - RX path timeout of data reception leads to -ETIMEDOUT
0008  * - RX path SN mismatch leads to -EILSEQ
0009  * - RX path data reception with wrong padding leads to -EBADMSG
0010  * - TX path flowcontrol reception timeout leads to -ECOMM
0011  * - TX path flowcontrol reception overflow leads to -EMSGSIZE
0012  * - TX path flowcontrol reception with wrong layout/padding leads to -EBADMSG
0013  * - when a transfer (tx) is on the run the next write() blocks until it's done
0014  * - use CAN_ISOTP_WAIT_TX_DONE flag to block the caller until the PDU is sent
0015  * - as we have static buffers the check whether the PDU fits into the buffer
0016  *   is done at FF reception time (no support for sending 'wait frames')
0017  *
0018  * Copyright (c) 2020 Volkswagen Group Electronic Research
0019  * All rights reserved.
0020  *
0021  * Redistribution and use in source and binary forms, with or without
0022  * modification, are permitted provided that the following conditions
0023  * are met:
0024  * 1. Redistributions of source code must retain the above copyright
0025  *    notice, this list of conditions and the following disclaimer.
0026  * 2. Redistributions in binary form must reproduce the above copyright
0027  *    notice, this list of conditions and the following disclaimer in the
0028  *    documentation and/or other materials provided with the distribution.
0029  * 3. Neither the name of Volkswagen nor the names of its contributors
0030  *    may be used to endorse or promote products derived from this software
0031  *    without specific prior written permission.
0032  *
0033  * Alternatively, provided that this notice is retained in full, this
0034  * software may be distributed under the terms of the GNU General
0035  * Public License ("GPL") version 2, in which case the provisions of the
0036  * GPL apply INSTEAD OF those given above.
0037  *
0038  * The provided data structures and external interfaces from this code
0039  * are not restricted to be used by modules with a GPL compatible license.
0040  *
0041  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
0042  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
0043  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
0044  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
0045  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
0046  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
0047  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
0048  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
0049  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
0050  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
0051  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
0052  * DAMAGE.
0053  */
0054 
0055 #include <linux/module.h>
0056 #include <linux/init.h>
0057 #include <linux/interrupt.h>
0058 #include <linux/spinlock.h>
0059 #include <linux/hrtimer.h>
0060 #include <linux/wait.h>
0061 #include <linux/uio.h>
0062 #include <linux/net.h>
0063 #include <linux/netdevice.h>
0064 #include <linux/socket.h>
0065 #include <linux/if_arp.h>
0066 #include <linux/skbuff.h>
0067 #include <linux/can.h>
0068 #include <linux/can/core.h>
0069 #include <linux/can/skb.h>
0070 #include <linux/can/isotp.h>
0071 #include <linux/slab.h>
0072 #include <net/sock.h>
0073 #include <net/net_namespace.h>
0074 
0075 MODULE_DESCRIPTION("PF_CAN isotp 15765-2:2016 protocol");
0076 MODULE_LICENSE("Dual BSD/GPL");
0077 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
0078 MODULE_ALIAS("can-proto-6");
0079 
0080 #define ISOTP_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp)
0081 
0082 #define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
0083              (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
0084              (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
0085 
0086 /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
0087  * take full 32 bit values (4 Gbyte). We would need some good concept to handle
0088  * this between user space and kernel space. For now increase the static buffer
0089  * to something about 64 kbyte to be able to test this new functionality.
0090  */
0091 #define MAX_MSG_LENGTH 66000
0092 
0093 /* N_PCI type values in bits 7-4 of N_PCI bytes */
0094 #define N_PCI_SF 0x00   /* single frame */
0095 #define N_PCI_FF 0x10   /* first frame */
0096 #define N_PCI_CF 0x20   /* consecutive frame */
0097 #define N_PCI_FC 0x30   /* flow control */
0098 
0099 #define N_PCI_SZ 1  /* size of the PCI byte #1 */
0100 #define SF_PCI_SZ4 1    /* size of SingleFrame PCI including 4 bit SF_DL */
0101 #define SF_PCI_SZ8 2    /* size of SingleFrame PCI including 8 bit SF_DL */
0102 #define FF_PCI_SZ12 2   /* size of FirstFrame PCI including 12 bit FF_DL */
0103 #define FF_PCI_SZ32 6   /* size of FirstFrame PCI including 32 bit FF_DL */
0104 #define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
0105 
0106 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
0107 #define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)
0108 
0109 /* Flow Status given in FC frame */
0110 #define ISOTP_FC_CTS 0      /* clear to send */
0111 #define ISOTP_FC_WT 1       /* wait */
0112 #define ISOTP_FC_OVFLW 2    /* overflow */
0113 
0114 enum {
0115     ISOTP_IDLE = 0,
0116     ISOTP_WAIT_FIRST_FC,
0117     ISOTP_WAIT_FC,
0118     ISOTP_WAIT_DATA,
0119     ISOTP_SENDING
0120 };
0121 
0122 struct tpcon {
0123     unsigned int idx;
0124     unsigned int len;
0125     u32 state;
0126     u8 bs;
0127     u8 sn;
0128     u8 ll_dl;
0129     u8 buf[MAX_MSG_LENGTH + 1];
0130 };
0131 
0132 struct isotp_sock {
0133     struct sock sk;
0134     int bound;
0135     int ifindex;
0136     canid_t txid;
0137     canid_t rxid;
0138     ktime_t tx_gap;
0139     ktime_t lastrxcf_tstamp;
0140     struct hrtimer rxtimer, txtimer;
0141     struct can_isotp_options opt;
0142     struct can_isotp_fc_options rxfc, txfc;
0143     struct can_isotp_ll_options ll;
0144     u32 frame_txtime;
0145     u32 force_tx_stmin;
0146     u32 force_rx_stmin;
0147     u32 cfecho; /* consecutive frame echo tag */
0148     struct tpcon rx, tx;
0149     struct list_head notifier;
0150     wait_queue_head_t wait;
0151     spinlock_t rx_lock; /* protect single thread state machine */
0152 };
0153 
0154 static LIST_HEAD(isotp_notifier_list);
0155 static DEFINE_SPINLOCK(isotp_notifier_lock);
0156 static struct isotp_sock *isotp_busy_notifier;
0157 
0158 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
0159 {
0160     return (struct isotp_sock *)sk;
0161 }
0162 
0163 static u32 isotp_bc_flags(struct isotp_sock *so)
0164 {
0165     return so->opt.flags & ISOTP_ALL_BC_FLAGS;
0166 }
0167 
0168 static bool isotp_register_rxid(struct isotp_sock *so)
0169 {
0170     /* no broadcast modes => register rx_id for FC frame reception */
0171     return (isotp_bc_flags(so) == 0);
0172 }
0173 
0174 static bool isotp_register_txecho(struct isotp_sock *so)
0175 {
0176     /* all modes but SF_BROADCAST register for tx echo skbs */
0177     return (isotp_bc_flags(so) != CAN_ISOTP_SF_BROADCAST);
0178 }
0179 
0180 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
0181 {
0182     struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
0183                          rxtimer);
0184     struct sock *sk = &so->sk;
0185 
0186     if (so->rx.state == ISOTP_WAIT_DATA) {
0187         /* we did not get new data frames in time */
0188 
0189         /* report 'connection timed out' */
0190         sk->sk_err = ETIMEDOUT;
0191         if (!sock_flag(sk, SOCK_DEAD))
0192             sk_error_report(sk);
0193 
0194         /* reset rx state */
0195         so->rx.state = ISOTP_IDLE;
0196     }
0197 
0198     return HRTIMER_NORESTART;
0199 }
0200 
0201 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
0202 {
0203     struct net_device *dev;
0204     struct sk_buff *nskb;
0205     struct canfd_frame *ncf;
0206     struct isotp_sock *so = isotp_sk(sk);
0207     int can_send_ret;
0208 
0209     nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any());
0210     if (!nskb)
0211         return 1;
0212 
0213     dev = dev_get_by_index(sock_net(sk), so->ifindex);
0214     if (!dev) {
0215         kfree_skb(nskb);
0216         return 1;
0217     }
0218 
0219     can_skb_reserve(nskb);
0220     can_skb_prv(nskb)->ifindex = dev->ifindex;
0221     can_skb_prv(nskb)->skbcnt = 0;
0222 
0223     nskb->dev = dev;
0224     can_skb_set_owner(nskb, sk);
0225     ncf = (struct canfd_frame *)nskb->data;
0226     skb_put_zero(nskb, so->ll.mtu);
0227 
0228     /* create & send flow control reply */
0229     ncf->can_id = so->txid;
0230 
0231     if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
0232         memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
0233         ncf->len = CAN_MAX_DLEN;
0234     } else {
0235         ncf->len = ae + FC_CONTENT_SZ;
0236     }
0237 
0238     ncf->data[ae] = N_PCI_FC | flowstatus;
0239     ncf->data[ae + 1] = so->rxfc.bs;
0240     ncf->data[ae + 2] = so->rxfc.stmin;
0241 
0242     if (ae)
0243         ncf->data[0] = so->opt.ext_address;
0244 
0245     ncf->flags = so->ll.tx_flags;
0246 
0247     can_send_ret = can_send(nskb, 1);
0248     if (can_send_ret)
0249         pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
0250                    __func__, ERR_PTR(can_send_ret));
0251 
0252     dev_put(dev);
0253 
0254     /* reset blocksize counter */
0255     so->rx.bs = 0;
0256 
0257     /* reset last CF frame rx timestamp for rx stmin enforcement */
0258     so->lastrxcf_tstamp = ktime_set(0, 0);
0259 
0260     /* start rx timeout watchdog */
0261     hrtimer_start(&so->rxtimer, ktime_set(1, 0), HRTIMER_MODE_REL_SOFT);
0262     return 0;
0263 }
0264 
0265 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
0266 {
0267     struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
0268 
0269     BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
0270 
0271     memset(addr, 0, sizeof(*addr));
0272     addr->can_family = AF_CAN;
0273     addr->can_ifindex = skb->dev->ifindex;
0274 
0275     if (sock_queue_rcv_skb(sk, skb) < 0)
0276         kfree_skb(skb);
0277 }
0278 
0279 static u8 padlen(u8 datalen)
0280 {
0281     static const u8 plen[] = {
0282         8, 8, 8, 8, 8, 8, 8, 8, 8,  /* 0 - 8 */
0283         12, 12, 12, 12,         /* 9 - 12 */
0284         16, 16, 16, 16,         /* 13 - 16 */
0285         20, 20, 20, 20,         /* 17 - 20 */
0286         24, 24, 24, 24,         /* 21 - 24 */
0287         32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
0288         48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
0289         48, 48, 48, 48, 48, 48, 48, 48  /* 41 - 48 */
0290     };
0291 
0292     if (datalen > 48)
0293         return 64;
0294 
0295     return plen[datalen];
0296 }
0297 
0298 /* check for length optimization and return 1/true when the check fails */
0299 static int check_optimized(struct canfd_frame *cf, int start_index)
0300 {
0301     /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
0302      * padding would start at this point. E.g. if the padding would
0303      * start at cf.data[7] cf->len has to be 7 to be optimal.
0304      * Note: The data[] index starts with zero.
0305      */
0306     if (cf->len <= CAN_MAX_DLEN)
0307         return (cf->len != start_index);
0308 
0309     /* This relation is also valid in the non-linear DLC range, where
0310      * we need to take care of the minimal next possible CAN_DL.
0311      * The correct check would be (padlen(cf->len) != padlen(start_index)).
0312      * But as cf->len can only take discrete values from 12, .., 64 at this
0313      * point the padlen(cf->len) is always equal to cf->len.
0314      */
0315     return (cf->len != padlen(start_index));
0316 }
0317 
0318 /* check padding and return 1/true when the check fails */
0319 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
0320              int start_index, u8 content)
0321 {
0322     int i;
0323 
0324     /* no RX_PADDING value => check length of optimized frame length */
0325     if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
0326         if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
0327             return check_optimized(cf, start_index);
0328 
0329         /* no valid test against empty value => ignore frame */
0330         return 1;
0331     }
0332 
0333     /* check datalength of correctly padded CAN frame */
0334     if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
0335         cf->len != padlen(cf->len))
0336         return 1;
0337 
0338     /* check padding content */
0339     if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
0340         for (i = start_index; i < cf->len; i++)
0341             if (cf->data[i] != content)
0342                 return 1;
0343     }
0344     return 0;
0345 }
0346 
0347 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
0348 {
0349     struct sock *sk = &so->sk;
0350 
0351     if (so->tx.state != ISOTP_WAIT_FC &&
0352         so->tx.state != ISOTP_WAIT_FIRST_FC)
0353         return 0;
0354 
0355     hrtimer_cancel(&so->txtimer);
0356 
0357     if ((cf->len < ae + FC_CONTENT_SZ) ||
0358         ((so->opt.flags & ISOTP_CHECK_PADDING) &&
0359          check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
0360         /* malformed PDU - report 'not a data message' */
0361         sk->sk_err = EBADMSG;
0362         if (!sock_flag(sk, SOCK_DEAD))
0363             sk_error_report(sk);
0364 
0365         so->tx.state = ISOTP_IDLE;
0366         wake_up_interruptible(&so->wait);
0367         return 1;
0368     }
0369 
0370     /* get communication parameters only from the first FC frame */
0371     if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
0372         so->txfc.bs = cf->data[ae + 1];
0373         so->txfc.stmin = cf->data[ae + 2];
0374 
0375         /* fix wrong STmin values according spec */
0376         if (so->txfc.stmin > 0x7F &&
0377             (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
0378             so->txfc.stmin = 0x7F;
0379 
0380         so->tx_gap = ktime_set(0, 0);
0381         /* add transmission time for CAN frame N_As */
0382         so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
0383         /* add waiting time for consecutive frames N_Cs */
0384         if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
0385             so->tx_gap = ktime_add_ns(so->tx_gap,
0386                           so->force_tx_stmin);
0387         else if (so->txfc.stmin < 0x80)
0388             so->tx_gap = ktime_add_ns(so->tx_gap,
0389                           so->txfc.stmin * 1000000);
0390         else
0391             so->tx_gap = ktime_add_ns(so->tx_gap,
0392                           (so->txfc.stmin - 0xF0)
0393                           * 100000);
0394         so->tx.state = ISOTP_WAIT_FC;
0395     }
0396 
0397     switch (cf->data[ae] & 0x0F) {
0398     case ISOTP_FC_CTS:
0399         so->tx.bs = 0;
0400         so->tx.state = ISOTP_SENDING;
0401         /* start cyclic timer for sending CF frame */
0402         hrtimer_start(&so->txtimer, so->tx_gap,
0403                   HRTIMER_MODE_REL_SOFT);
0404         break;
0405 
0406     case ISOTP_FC_WT:
0407         /* start timer to wait for next FC frame */
0408         hrtimer_start(&so->txtimer, ktime_set(1, 0),
0409                   HRTIMER_MODE_REL_SOFT);
0410         break;
0411 
0412     case ISOTP_FC_OVFLW:
0413         /* overflow on receiver side - report 'message too long' */
0414         sk->sk_err = EMSGSIZE;
0415         if (!sock_flag(sk, SOCK_DEAD))
0416             sk_error_report(sk);
0417         fallthrough;
0418 
0419     default:
0420         /* stop this tx job */
0421         so->tx.state = ISOTP_IDLE;
0422         wake_up_interruptible(&so->wait);
0423     }
0424     return 0;
0425 }
0426 
0427 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
0428             struct sk_buff *skb, int len)
0429 {
0430     struct isotp_sock *so = isotp_sk(sk);
0431     struct sk_buff *nskb;
0432 
0433     hrtimer_cancel(&so->rxtimer);
0434     so->rx.state = ISOTP_IDLE;
0435 
0436     if (!len || len > cf->len - pcilen)
0437         return 1;
0438 
0439     if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
0440         check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
0441         /* malformed PDU - report 'not a data message' */
0442         sk->sk_err = EBADMSG;
0443         if (!sock_flag(sk, SOCK_DEAD))
0444             sk_error_report(sk);
0445         return 1;
0446     }
0447 
0448     nskb = alloc_skb(len, gfp_any());
0449     if (!nskb)
0450         return 1;
0451 
0452     memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
0453 
0454     nskb->tstamp = skb->tstamp;
0455     nskb->dev = skb->dev;
0456     isotp_rcv_skb(nskb, sk);
0457     return 0;
0458 }
0459 
0460 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
0461 {
0462     struct isotp_sock *so = isotp_sk(sk);
0463     int i;
0464     int off;
0465     int ff_pci_sz;
0466 
0467     hrtimer_cancel(&so->rxtimer);
0468     so->rx.state = ISOTP_IDLE;
0469 
0470     /* get the used sender LL_DL from the (first) CAN frame data length */
0471     so->rx.ll_dl = padlen(cf->len);
0472 
0473     /* the first frame has to use the entire frame up to LL_DL length */
0474     if (cf->len != so->rx.ll_dl)
0475         return 1;
0476 
0477     /* get the FF_DL */
0478     so->rx.len = (cf->data[ae] & 0x0F) << 8;
0479     so->rx.len += cf->data[ae + 1];
0480 
0481     /* Check for FF_DL escape sequence supporting 32 bit PDU length */
0482     if (so->rx.len) {
0483         ff_pci_sz = FF_PCI_SZ12;
0484     } else {
0485         /* FF_DL = 0 => get real length from next 4 bytes */
0486         so->rx.len = cf->data[ae + 2] << 24;
0487         so->rx.len += cf->data[ae + 3] << 16;
0488         so->rx.len += cf->data[ae + 4] << 8;
0489         so->rx.len += cf->data[ae + 5];
0490         ff_pci_sz = FF_PCI_SZ32;
0491     }
0492 
0493     /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
0494     off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
0495 
0496     if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
0497         return 1;
0498 
0499     if (so->rx.len > MAX_MSG_LENGTH) {
0500         /* send FC frame with overflow status */
0501         isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
0502         return 1;
0503     }
0504 
0505     /* copy the first received data bytes */
0506     so->rx.idx = 0;
0507     for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
0508         so->rx.buf[so->rx.idx++] = cf->data[i];
0509 
0510     /* initial setup for this pdu reception */
0511     so->rx.sn = 1;
0512     so->rx.state = ISOTP_WAIT_DATA;
0513 
0514     /* no creation of flow control frames */
0515     if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
0516         return 0;
0517 
0518     /* send our first FC frame */
0519     isotp_send_fc(sk, ae, ISOTP_FC_CTS);
0520     return 0;
0521 }
0522 
0523 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
0524             struct sk_buff *skb)
0525 {
0526     struct isotp_sock *so = isotp_sk(sk);
0527     struct sk_buff *nskb;
0528     int i;
0529 
0530     if (so->rx.state != ISOTP_WAIT_DATA)
0531         return 0;
0532 
0533     /* drop if timestamp gap is less than force_rx_stmin nano secs */
0534     if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
0535         if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
0536             so->force_rx_stmin)
0537             return 0;
0538 
0539         so->lastrxcf_tstamp = skb->tstamp;
0540     }
0541 
0542     hrtimer_cancel(&so->rxtimer);
0543 
0544     /* CFs are never longer than the FF */
0545     if (cf->len > so->rx.ll_dl)
0546         return 1;
0547 
0548     /* CFs have usually the LL_DL length */
0549     if (cf->len < so->rx.ll_dl) {
0550         /* this is only allowed for the last CF */
0551         if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
0552             return 1;
0553     }
0554 
0555     if ((cf->data[ae] & 0x0F) != so->rx.sn) {
0556         /* wrong sn detected - report 'illegal byte sequence' */
0557         sk->sk_err = EILSEQ;
0558         if (!sock_flag(sk, SOCK_DEAD))
0559             sk_error_report(sk);
0560 
0561         /* reset rx state */
0562         so->rx.state = ISOTP_IDLE;
0563         return 1;
0564     }
0565     so->rx.sn++;
0566     so->rx.sn %= 16;
0567 
0568     for (i = ae + N_PCI_SZ; i < cf->len; i++) {
0569         so->rx.buf[so->rx.idx++] = cf->data[i];
0570         if (so->rx.idx >= so->rx.len)
0571             break;
0572     }
0573 
0574     if (so->rx.idx >= so->rx.len) {
0575         /* we are done */
0576         so->rx.state = ISOTP_IDLE;
0577 
0578         if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
0579             check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
0580             /* malformed PDU - report 'not a data message' */
0581             sk->sk_err = EBADMSG;
0582             if (!sock_flag(sk, SOCK_DEAD))
0583                 sk_error_report(sk);
0584             return 1;
0585         }
0586 
0587         nskb = alloc_skb(so->rx.len, gfp_any());
0588         if (!nskb)
0589             return 1;
0590 
0591         memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
0592                so->rx.len);
0593 
0594         nskb->tstamp = skb->tstamp;
0595         nskb->dev = skb->dev;
0596         isotp_rcv_skb(nskb, sk);
0597         return 0;
0598     }
0599 
0600     /* perform blocksize handling, if enabled */
0601     if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
0602         /* start rx timeout watchdog */
0603         hrtimer_start(&so->rxtimer, ktime_set(1, 0),
0604                   HRTIMER_MODE_REL_SOFT);
0605         return 0;
0606     }
0607 
0608     /* no creation of flow control frames */
0609     if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
0610         return 0;
0611 
0612     /* we reached the specified blocksize so->rxfc.bs */
0613     isotp_send_fc(sk, ae, ISOTP_FC_CTS);
0614     return 0;
0615 }
0616 
0617 static void isotp_rcv(struct sk_buff *skb, void *data)
0618 {
0619     struct sock *sk = (struct sock *)data;
0620     struct isotp_sock *so = isotp_sk(sk);
0621     struct canfd_frame *cf;
0622     int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
0623     u8 n_pci_type, sf_dl;
0624 
0625     /* Strictly receive only frames with the configured MTU size
0626      * => clear separation of CAN2.0 / CAN FD transport channels
0627      */
0628     if (skb->len != so->ll.mtu)
0629         return;
0630 
0631     cf = (struct canfd_frame *)skb->data;
0632 
0633     /* if enabled: check reception of my configured extended address */
0634     if (ae && cf->data[0] != so->opt.rx_ext_address)
0635         return;
0636 
0637     n_pci_type = cf->data[ae] & 0xF0;
0638 
0639     /* Make sure the state changes and data structures stay consistent at
0640      * CAN frame reception time. This locking is not needed in real world
0641      * use cases but the inconsistency can be triggered with syzkaller.
0642      */
0643     spin_lock(&so->rx_lock);
0644 
0645     if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
0646         /* check rx/tx path half duplex expectations */
0647         if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
0648             (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
0649             goto out_unlock;
0650     }
0651 
0652     switch (n_pci_type) {
0653     case N_PCI_FC:
0654         /* tx path: flow control frame containing the FC parameters */
0655         isotp_rcv_fc(so, cf, ae);
0656         break;
0657 
0658     case N_PCI_SF:
0659         /* rx path: single frame
0660          *
0661          * As we do not have a rx.ll_dl configuration, we can only test
0662          * if the CAN frames payload length matches the LL_DL == 8
0663          * requirements - no matter if it's CAN 2.0 or CAN FD
0664          */
0665 
0666         /* get the SF_DL from the N_PCI byte */
0667         sf_dl = cf->data[ae] & 0x0F;
0668 
0669         if (cf->len <= CAN_MAX_DLEN) {
0670             isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
0671         } else {
0672             if (skb->len == CANFD_MTU) {
0673                 /* We have a CAN FD frame and CAN_DL is greater than 8:
0674                  * Only frames with the SF_DL == 0 ESC value are valid.
0675                  *
0676                  * If so take care of the increased SF PCI size
0677                  * (SF_PCI_SZ8) to point to the message content behind
0678                  * the extended SF PCI info and get the real SF_DL
0679                  * length value from the formerly first data byte.
0680                  */
0681                 if (sf_dl == 0)
0682                     isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
0683                              cf->data[SF_PCI_SZ4 + ae]);
0684             }
0685         }
0686         break;
0687 
0688     case N_PCI_FF:
0689         /* rx path: first frame */
0690         isotp_rcv_ff(sk, cf, ae);
0691         break;
0692 
0693     case N_PCI_CF:
0694         /* rx path: consecutive frame */
0695         isotp_rcv_cf(sk, cf, ae, skb);
0696         break;
0697     }
0698 
0699 out_unlock:
0700     spin_unlock(&so->rx_lock);
0701 }
0702 
0703 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
0704                  int ae, int off)
0705 {
0706     int pcilen = N_PCI_SZ + ae + off;
0707     int space = so->tx.ll_dl - pcilen;
0708     int num = min_t(int, so->tx.len - so->tx.idx, space);
0709     int i;
0710 
0711     cf->can_id = so->txid;
0712     cf->len = num + pcilen;
0713 
0714     if (num < space) {
0715         if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
0716             /* user requested padding */
0717             cf->len = padlen(cf->len);
0718             memset(cf->data, so->opt.txpad_content, cf->len);
0719         } else if (cf->len > CAN_MAX_DLEN) {
0720             /* mandatory padding for CAN FD frames */
0721             cf->len = padlen(cf->len);
0722             memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
0723                    cf->len);
0724         }
0725     }
0726 
0727     for (i = 0; i < num; i++)
0728         cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
0729 
0730     if (ae)
0731         cf->data[0] = so->opt.ext_address;
0732 }
0733 
0734 static void isotp_send_cframe(struct isotp_sock *so)
0735 {
0736     struct sock *sk = &so->sk;
0737     struct sk_buff *skb;
0738     struct net_device *dev;
0739     struct canfd_frame *cf;
0740     int can_send_ret;
0741     int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
0742 
0743     dev = dev_get_by_index(sock_net(sk), so->ifindex);
0744     if (!dev)
0745         return;
0746 
0747     skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), GFP_ATOMIC);
0748     if (!skb) {
0749         dev_put(dev);
0750         return;
0751     }
0752 
0753     can_skb_reserve(skb);
0754     can_skb_prv(skb)->ifindex = dev->ifindex;
0755     can_skb_prv(skb)->skbcnt = 0;
0756 
0757     cf = (struct canfd_frame *)skb->data;
0758     skb_put_zero(skb, so->ll.mtu);
0759 
0760     /* create consecutive frame */
0761     isotp_fill_dataframe(cf, so, ae, 0);
0762 
0763     /* place consecutive frame N_PCI in appropriate index */
0764     cf->data[ae] = N_PCI_CF | so->tx.sn++;
0765     so->tx.sn %= 16;
0766     so->tx.bs++;
0767 
0768     cf->flags = so->ll.tx_flags;
0769 
0770     skb->dev = dev;
0771     can_skb_set_owner(skb, sk);
0772 
0773     /* cfecho should have been zero'ed by init/isotp_rcv_echo() */
0774     if (so->cfecho)
0775         pr_notice_once("can-isotp: cfecho is %08X != 0\n", so->cfecho);
0776 
0777     /* set consecutive frame echo tag */
0778     so->cfecho = *(u32 *)cf->data;
0779 
0780     /* send frame with local echo enabled */
0781     can_send_ret = can_send(skb, 1);
0782     if (can_send_ret) {
0783         pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
0784                    __func__, ERR_PTR(can_send_ret));
0785         if (can_send_ret == -ENOBUFS)
0786             pr_notice_once("can-isotp: tx queue is full\n");
0787     }
0788     dev_put(dev);
0789 }
0790 
0791 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
0792                 int ae)
0793 {
0794     int i;
0795     int ff_pci_sz;
0796 
0797     cf->can_id = so->txid;
0798     cf->len = so->tx.ll_dl;
0799     if (ae)
0800         cf->data[0] = so->opt.ext_address;
0801 
0802     /* create N_PCI bytes with 12/32 bit FF_DL data length */
0803     if (so->tx.len > 4095) {
0804         /* use 32 bit FF_DL notation */
0805         cf->data[ae] = N_PCI_FF;
0806         cf->data[ae + 1] = 0;
0807         cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
0808         cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
0809         cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
0810         cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
0811         ff_pci_sz = FF_PCI_SZ32;
0812     } else {
0813         /* use 12 bit FF_DL notation */
0814         cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
0815         cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
0816         ff_pci_sz = FF_PCI_SZ12;
0817     }
0818 
0819     /* add first data bytes depending on ae */
0820     for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
0821         cf->data[i] = so->tx.buf[so->tx.idx++];
0822 
0823     so->tx.sn = 1;
0824 }
0825 
0826 static void isotp_rcv_echo(struct sk_buff *skb, void *data)
0827 {
0828     struct sock *sk = (struct sock *)data;
0829     struct isotp_sock *so = isotp_sk(sk);
0830     struct canfd_frame *cf = (struct canfd_frame *)skb->data;
0831 
0832     /* only handle my own local echo skb's */
0833     if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
0834         return;
0835 
0836     /* cancel local echo timeout */
0837     hrtimer_cancel(&so->txtimer);
0838 
0839     /* local echo skb with consecutive frame has been consumed */
0840     so->cfecho = 0;
0841 
0842     if (so->tx.idx >= so->tx.len) {
0843         /* we are done */
0844         so->tx.state = ISOTP_IDLE;
0845         wake_up_interruptible(&so->wait);
0846         return;
0847     }
0848 
0849     if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
0850         /* stop and wait for FC with timeout */
0851         so->tx.state = ISOTP_WAIT_FC;
0852         hrtimer_start(&so->txtimer, ktime_set(1, 0),
0853                   HRTIMER_MODE_REL_SOFT);
0854         return;
0855     }
0856 
0857     /* no gap between data frames needed => use burst mode */
0858     if (!so->tx_gap) {
0859         isotp_send_cframe(so);
0860         return;
0861     }
0862 
0863     /* start timer to send next consecutive frame with correct delay */
0864     hrtimer_start(&so->txtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
0865 }
0866 
0867 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
0868 {
0869     struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
0870                          txtimer);
0871     struct sock *sk = &so->sk;
0872     enum hrtimer_restart restart = HRTIMER_NORESTART;
0873 
0874     switch (so->tx.state) {
0875     case ISOTP_SENDING:
0876 
0877         /* cfecho should be consumed by isotp_rcv_echo() here */
0878         if (!so->cfecho) {
0879             /* start timeout for unlikely lost echo skb */
0880             hrtimer_set_expires(&so->txtimer,
0881                         ktime_add(ktime_get(),
0882                               ktime_set(2, 0)));
0883             restart = HRTIMER_RESTART;
0884 
0885             /* push out the next consecutive frame */
0886             isotp_send_cframe(so);
0887             break;
0888         }
0889 
0890         /* cfecho has not been cleared in isotp_rcv_echo() */
0891         pr_notice_once("can-isotp: cfecho %08X timeout\n", so->cfecho);
0892         fallthrough;
0893 
0894     case ISOTP_WAIT_FC:
0895     case ISOTP_WAIT_FIRST_FC:
0896 
0897         /* we did not get any flow control frame in time */
0898 
0899         /* report 'communication error on send' */
0900         sk->sk_err = ECOMM;
0901         if (!sock_flag(sk, SOCK_DEAD))
0902             sk_error_report(sk);
0903 
0904         /* reset tx state */
0905         so->tx.state = ISOTP_IDLE;
0906         wake_up_interruptible(&so->wait);
0907         break;
0908 
0909     default:
0910         WARN_ON_ONCE(1);
0911     }
0912 
0913     return restart;
0914 }
0915 
0916 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
0917 {
0918     struct sock *sk = sock->sk;
0919     struct isotp_sock *so = isotp_sk(sk);
0920     u32 old_state = so->tx.state;
0921     struct sk_buff *skb;
0922     struct net_device *dev;
0923     struct canfd_frame *cf;
0924     int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
0925     int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
0926     s64 hrtimer_sec = 0;
0927     int off;
0928     int err;
0929 
0930     if (!so->bound)
0931         return -EADDRNOTAVAIL;
0932 
0933     /* we do not support multiple buffers - for now */
0934     if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE ||
0935         wq_has_sleeper(&so->wait)) {
0936         if (msg->msg_flags & MSG_DONTWAIT) {
0937             err = -EAGAIN;
0938             goto err_out;
0939         }
0940 
0941         /* wait for complete transmission of current pdu */
0942         err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
0943         if (err)
0944             goto err_out;
0945     }
0946 
0947     if (!size || size > MAX_MSG_LENGTH) {
0948         err = -EINVAL;
0949         goto err_out_drop;
0950     }
0951 
0952     /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
0953     off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
0954 
0955     /* does the given data fit into a single frame for SF_BROADCAST? */
0956     if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
0957         (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
0958         err = -EINVAL;
0959         goto err_out_drop;
0960     }
0961 
0962     err = memcpy_from_msg(so->tx.buf, msg, size);
0963     if (err < 0)
0964         goto err_out_drop;
0965 
0966     dev = dev_get_by_index(sock_net(sk), so->ifindex);
0967     if (!dev) {
0968         err = -ENXIO;
0969         goto err_out_drop;
0970     }
0971 
0972     skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
0973                   msg->msg_flags & MSG_DONTWAIT, &err);
0974     if (!skb) {
0975         dev_put(dev);
0976         goto err_out_drop;
0977     }
0978 
0979     can_skb_reserve(skb);
0980     can_skb_prv(skb)->ifindex = dev->ifindex;
0981     can_skb_prv(skb)->skbcnt = 0;
0982 
0983     so->tx.len = size;
0984     so->tx.idx = 0;
0985 
0986     cf = (struct canfd_frame *)skb->data;
0987     skb_put_zero(skb, so->ll.mtu);
0988 
0989     /* check for single frame transmission depending on TX_DL */
0990     if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
0991         /* The message size generally fits into a SingleFrame - good.
0992          *
0993          * SF_DL ESC offset optimization:
0994          *
0995          * When TX_DL is greater 8 but the message would still fit
0996          * into a 8 byte CAN frame, we can omit the offset.
0997          * This prevents a protocol caused length extension from
0998          * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
0999          */
1000         if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1001             off = 0;
1002 
1003         isotp_fill_dataframe(cf, so, ae, off);
1004 
1005         /* place single frame N_PCI w/o length in appropriate index */
1006         cf->data[ae] = N_PCI_SF;
1007 
1008         /* place SF_DL size value depending on the SF_DL ESC offset */
1009         if (off)
1010             cf->data[SF_PCI_SZ4 + ae] = size;
1011         else
1012             cf->data[ae] |= size;
1013 
1014         so->tx.state = ISOTP_IDLE;
1015         wake_up_interruptible(&so->wait);
1016 
1017         /* don't enable wait queue for a single frame transmission */
1018         wait_tx_done = 0;
1019     } else {
1020         /* send first frame */
1021 
1022         isotp_create_fframe(cf, so, ae);
1023 
1024         if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1025             /* set timer for FC-less operation (STmin = 0) */
1026             if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1027                 so->tx_gap = ktime_set(0, so->force_tx_stmin);
1028             else
1029                 so->tx_gap = ktime_set(0, so->frame_txtime);
1030 
1031             /* disable wait for FCs due to activated block size */
1032             so->txfc.bs = 0;
1033 
1034             /* cfecho should have been zero'ed by init */
1035             if (so->cfecho)
1036                 pr_notice_once("can-isotp: no fc cfecho %08X\n",
1037                            so->cfecho);
1038 
1039             /* set consecutive frame echo tag */
1040             so->cfecho = *(u32 *)cf->data;
1041 
1042             /* switch directly to ISOTP_SENDING state */
1043             so->tx.state = ISOTP_SENDING;
1044 
1045             /* start timeout for unlikely lost echo skb */
1046             hrtimer_sec = 2;
1047         } else {
1048             /* standard flow control check */
1049             so->tx.state = ISOTP_WAIT_FIRST_FC;
1050 
1051             /* start timeout for FC */
1052             hrtimer_sec = 1;
1053         }
1054 
1055         hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
1056                   HRTIMER_MODE_REL_SOFT);
1057     }
1058 
1059     /* send the first or only CAN frame */
1060     cf->flags = so->ll.tx_flags;
1061 
1062     skb->dev = dev;
1063     skb->sk = sk;
1064     err = can_send(skb, 1);
1065     dev_put(dev);
1066     if (err) {
1067         pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1068                    __func__, ERR_PTR(err));
1069 
1070         /* no transmission -> no timeout monitoring */
1071         if (hrtimer_sec)
1072             hrtimer_cancel(&so->txtimer);
1073 
1074         /* reset consecutive frame echo tag */
1075         so->cfecho = 0;
1076 
1077         goto err_out_drop;
1078     }
1079 
1080     if (wait_tx_done) {
1081         /* wait for complete transmission of current pdu */
1082         wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1083 
1084         if (sk->sk_err)
1085             return -sk->sk_err;
1086     }
1087 
1088     return size;
1089 
1090 err_out_drop:
1091     /* drop this PDU and unlock a potential wait queue */
1092     old_state = ISOTP_IDLE;
1093 err_out:
1094     so->tx.state = old_state;
1095     if (so->tx.state == ISOTP_IDLE)
1096         wake_up_interruptible(&so->wait);
1097 
1098     return err;
1099 }
1100 
1101 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1102              int flags)
1103 {
1104     struct sock *sk = sock->sk;
1105     struct sk_buff *skb;
1106     struct isotp_sock *so = isotp_sk(sk);
1107     int ret = 0;
1108 
1109     if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK))
1110         return -EINVAL;
1111 
1112     if (!so->bound)
1113         return -EADDRNOTAVAIL;
1114 
1115     skb = skb_recv_datagram(sk, flags, &ret);
1116     if (!skb)
1117         return ret;
1118 
1119     if (size < skb->len)
1120         msg->msg_flags |= MSG_TRUNC;
1121     else
1122         size = skb->len;
1123 
1124     ret = memcpy_to_msg(msg, skb->data, size);
1125     if (ret < 0)
1126         goto out_err;
1127 
1128     sock_recv_timestamp(msg, sk, skb);
1129 
1130     if (msg->msg_name) {
1131         __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1132         msg->msg_namelen = ISOTP_MIN_NAMELEN;
1133         memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1134     }
1135 
1136     /* set length of return value */
1137     ret = (flags & MSG_TRUNC) ? skb->len : size;
1138 
1139 out_err:
1140     skb_free_datagram(sk, skb);
1141 
1142     return ret;
1143 }
1144 
1145 static int isotp_release(struct socket *sock)
1146 {
1147     struct sock *sk = sock->sk;
1148     struct isotp_sock *so;
1149     struct net *net;
1150 
1151     if (!sk)
1152         return 0;
1153 
1154     so = isotp_sk(sk);
1155     net = sock_net(sk);
1156 
1157     /* wait for complete transmission of current pdu */
1158     wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1159 
1160     spin_lock(&isotp_notifier_lock);
1161     while (isotp_busy_notifier == so) {
1162         spin_unlock(&isotp_notifier_lock);
1163         schedule_timeout_uninterruptible(1);
1164         spin_lock(&isotp_notifier_lock);
1165     }
1166     list_del(&so->notifier);
1167     spin_unlock(&isotp_notifier_lock);
1168 
1169     lock_sock(sk);
1170 
1171     /* remove current filters & unregister */
1172     if (so->bound && isotp_register_txecho(so)) {
1173         if (so->ifindex) {
1174             struct net_device *dev;
1175 
1176             dev = dev_get_by_index(net, so->ifindex);
1177             if (dev) {
1178                 if (isotp_register_rxid(so))
1179                     can_rx_unregister(net, dev, so->rxid,
1180                               SINGLE_MASK(so->rxid),
1181                               isotp_rcv, sk);
1182 
1183                 can_rx_unregister(net, dev, so->txid,
1184                           SINGLE_MASK(so->txid),
1185                           isotp_rcv_echo, sk);
1186                 dev_put(dev);
1187                 synchronize_rcu();
1188             }
1189         }
1190     }
1191 
1192     hrtimer_cancel(&so->txtimer);
1193     hrtimer_cancel(&so->rxtimer);
1194 
1195     so->ifindex = 0;
1196     so->bound = 0;
1197 
1198     sock_orphan(sk);
1199     sock->sk = NULL;
1200 
1201     release_sock(sk);
1202     sock_put(sk);
1203 
1204     return 0;
1205 }
1206 
1207 static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
1208 {
1209     struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1210     struct sock *sk = sock->sk;
1211     struct isotp_sock *so = isotp_sk(sk);
1212     struct net *net = sock_net(sk);
1213     int ifindex;
1214     struct net_device *dev;
1215     canid_t tx_id = addr->can_addr.tp.tx_id;
1216     canid_t rx_id = addr->can_addr.tp.rx_id;
1217     int err = 0;
1218     int notify_enetdown = 0;
1219 
1220     if (len < ISOTP_MIN_NAMELEN)
1221         return -EINVAL;
1222 
1223     /* sanitize tx CAN identifier */
1224     if (tx_id & CAN_EFF_FLAG)
1225         tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1226     else
1227         tx_id &= CAN_SFF_MASK;
1228 
1229     /* give feedback on wrong CAN-ID value */
1230     if (tx_id != addr->can_addr.tp.tx_id)
1231         return -EINVAL;
1232 
1233     /* sanitize rx CAN identifier (if needed) */
1234     if (isotp_register_rxid(so)) {
1235         if (rx_id & CAN_EFF_FLAG)
1236             rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1237         else
1238             rx_id &= CAN_SFF_MASK;
1239 
1240         /* give feedback on wrong CAN-ID value */
1241         if (rx_id != addr->can_addr.tp.rx_id)
1242             return -EINVAL;
1243     }
1244 
1245     if (!addr->can_ifindex)
1246         return -ENODEV;
1247 
1248     lock_sock(sk);
1249 
1250     if (so->bound) {
1251         err = -EINVAL;
1252         goto out;
1253     }
1254 
1255     /* ensure different CAN IDs when the rx_id is to be registered */
1256     if (isotp_register_rxid(so) && rx_id == tx_id) {
1257         err = -EADDRNOTAVAIL;
1258         goto out;
1259     }
1260 
1261     dev = dev_get_by_index(net, addr->can_ifindex);
1262     if (!dev) {
1263         err = -ENODEV;
1264         goto out;
1265     }
1266     if (dev->type != ARPHRD_CAN) {
1267         dev_put(dev);
1268         err = -ENODEV;
1269         goto out;
1270     }
1271     if (dev->mtu < so->ll.mtu) {
1272         dev_put(dev);
1273         err = -EINVAL;
1274         goto out;
1275     }
1276     if (!(dev->flags & IFF_UP))
1277         notify_enetdown = 1;
1278 
1279     ifindex = dev->ifindex;
1280 
1281     if (isotp_register_rxid(so))
1282         can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
1283                 isotp_rcv, sk, "isotp", sk);
1284 
1285     if (isotp_register_txecho(so)) {
1286         /* no consecutive frame echo skb in flight */
1287         so->cfecho = 0;
1288 
1289         /* register for echo skb's */
1290         can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
1291                 isotp_rcv_echo, sk, "isotpe", sk);
1292     }
1293 
1294     dev_put(dev);
1295 
1296     /* switch to new settings */
1297     so->ifindex = ifindex;
1298     so->rxid = rx_id;
1299     so->txid = tx_id;
1300     so->bound = 1;
1301 
1302 out:
1303     release_sock(sk);
1304 
1305     if (notify_enetdown) {
1306         sk->sk_err = ENETDOWN;
1307         if (!sock_flag(sk, SOCK_DEAD))
1308             sk_error_report(sk);
1309     }
1310 
1311     return err;
1312 }
1313 
1314 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1315 {
1316     struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1317     struct sock *sk = sock->sk;
1318     struct isotp_sock *so = isotp_sk(sk);
1319 
1320     if (peer)
1321         return -EOPNOTSUPP;
1322 
1323     memset(addr, 0, ISOTP_MIN_NAMELEN);
1324     addr->can_family = AF_CAN;
1325     addr->can_ifindex = so->ifindex;
1326     addr->can_addr.tp.rx_id = so->rxid;
1327     addr->can_addr.tp.tx_id = so->txid;
1328 
1329     return ISOTP_MIN_NAMELEN;
1330 }
1331 
1332 static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1333                 sockptr_t optval, unsigned int optlen)
1334 {
1335     struct sock *sk = sock->sk;
1336     struct isotp_sock *so = isotp_sk(sk);
1337     int ret = 0;
1338 
1339     if (so->bound)
1340         return -EISCONN;
1341 
1342     switch (optname) {
1343     case CAN_ISOTP_OPTS:
1344         if (optlen != sizeof(struct can_isotp_options))
1345             return -EINVAL;
1346 
1347         if (copy_from_sockptr(&so->opt, optval, optlen))
1348             return -EFAULT;
1349 
1350         /* no separate rx_ext_address is given => use ext_address */
1351         if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1352             so->opt.rx_ext_address = so->opt.ext_address;
1353 
1354         /* these broadcast flags are not allowed together */
1355         if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1356             /* CAN_ISOTP_SF_BROADCAST is prioritized */
1357             so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1358 
1359             /* give user feedback on wrong config attempt */
1360             ret = -EINVAL;
1361         }
1362 
1363         /* check for frame_txtime changes (0 => no changes) */
1364         if (so->opt.frame_txtime) {
1365             if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1366                 so->frame_txtime = 0;
1367             else
1368                 so->frame_txtime = so->opt.frame_txtime;
1369         }
1370         break;
1371 
1372     case CAN_ISOTP_RECV_FC:
1373         if (optlen != sizeof(struct can_isotp_fc_options))
1374             return -EINVAL;
1375 
1376         if (copy_from_sockptr(&so->rxfc, optval, optlen))
1377             return -EFAULT;
1378         break;
1379 
1380     case CAN_ISOTP_TX_STMIN:
1381         if (optlen != sizeof(u32))
1382             return -EINVAL;
1383 
1384         if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1385             return -EFAULT;
1386         break;
1387 
1388     case CAN_ISOTP_RX_STMIN:
1389         if (optlen != sizeof(u32))
1390             return -EINVAL;
1391 
1392         if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1393             return -EFAULT;
1394         break;
1395 
1396     case CAN_ISOTP_LL_OPTS:
1397         if (optlen == sizeof(struct can_isotp_ll_options)) {
1398             struct can_isotp_ll_options ll;
1399 
1400             if (copy_from_sockptr(&ll, optval, optlen))
1401                 return -EFAULT;
1402 
1403             /* check for correct ISO 11898-1 DLC data length */
1404             if (ll.tx_dl != padlen(ll.tx_dl))
1405                 return -EINVAL;
1406 
1407             if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1408                 return -EINVAL;
1409 
1410             if (ll.mtu == CAN_MTU &&
1411                 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1412                 return -EINVAL;
1413 
1414             memcpy(&so->ll, &ll, sizeof(ll));
1415 
1416             /* set ll_dl for tx path to similar place as for rx */
1417             so->tx.ll_dl = ll.tx_dl;
1418         } else {
1419             return -EINVAL;
1420         }
1421         break;
1422 
1423     default:
1424         ret = -ENOPROTOOPT;
1425     }
1426 
1427     return ret;
1428 }
1429 
1430 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1431                 sockptr_t optval, unsigned int optlen)
1432 
1433 {
1434     struct sock *sk = sock->sk;
1435     int ret;
1436 
1437     if (level != SOL_CAN_ISOTP)
1438         return -EINVAL;
1439 
1440     lock_sock(sk);
1441     ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1442     release_sock(sk);
1443     return ret;
1444 }
1445 
1446 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1447                 char __user *optval, int __user *optlen)
1448 {
1449     struct sock *sk = sock->sk;
1450     struct isotp_sock *so = isotp_sk(sk);
1451     int len;
1452     void *val;
1453 
1454     if (level != SOL_CAN_ISOTP)
1455         return -EINVAL;
1456     if (get_user(len, optlen))
1457         return -EFAULT;
1458     if (len < 0)
1459         return -EINVAL;
1460 
1461     switch (optname) {
1462     case CAN_ISOTP_OPTS:
1463         len = min_t(int, len, sizeof(struct can_isotp_options));
1464         val = &so->opt;
1465         break;
1466 
1467     case CAN_ISOTP_RECV_FC:
1468         len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1469         val = &so->rxfc;
1470         break;
1471 
1472     case CAN_ISOTP_TX_STMIN:
1473         len = min_t(int, len, sizeof(u32));
1474         val = &so->force_tx_stmin;
1475         break;
1476 
1477     case CAN_ISOTP_RX_STMIN:
1478         len = min_t(int, len, sizeof(u32));
1479         val = &so->force_rx_stmin;
1480         break;
1481 
1482     case CAN_ISOTP_LL_OPTS:
1483         len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1484         val = &so->ll;
1485         break;
1486 
1487     default:
1488         return -ENOPROTOOPT;
1489     }
1490 
1491     if (put_user(len, optlen))
1492         return -EFAULT;
1493     if (copy_to_user(optval, val, len))
1494         return -EFAULT;
1495     return 0;
1496 }
1497 
1498 static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1499              struct net_device *dev)
1500 {
1501     struct sock *sk = &so->sk;
1502 
1503     if (!net_eq(dev_net(dev), sock_net(sk)))
1504         return;
1505 
1506     if (so->ifindex != dev->ifindex)
1507         return;
1508 
1509     switch (msg) {
1510     case NETDEV_UNREGISTER:
1511         lock_sock(sk);
1512         /* remove current filters & unregister */
1513         if (so->bound && isotp_register_txecho(so)) {
1514             if (isotp_register_rxid(so))
1515                 can_rx_unregister(dev_net(dev), dev, so->rxid,
1516                           SINGLE_MASK(so->rxid),
1517                           isotp_rcv, sk);
1518 
1519             can_rx_unregister(dev_net(dev), dev, so->txid,
1520                       SINGLE_MASK(so->txid),
1521                       isotp_rcv_echo, sk);
1522         }
1523 
1524         so->ifindex = 0;
1525         so->bound  = 0;
1526         release_sock(sk);
1527 
1528         sk->sk_err = ENODEV;
1529         if (!sock_flag(sk, SOCK_DEAD))
1530             sk_error_report(sk);
1531         break;
1532 
1533     case NETDEV_DOWN:
1534         sk->sk_err = ENETDOWN;
1535         if (!sock_flag(sk, SOCK_DEAD))
1536             sk_error_report(sk);
1537         break;
1538     }
1539 }
1540 
1541 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1542               void *ptr)
1543 {
1544     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1545 
1546     if (dev->type != ARPHRD_CAN)
1547         return NOTIFY_DONE;
1548     if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1549         return NOTIFY_DONE;
1550     if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1551         return NOTIFY_DONE;
1552 
1553     spin_lock(&isotp_notifier_lock);
1554     list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1555         spin_unlock(&isotp_notifier_lock);
1556         isotp_notify(isotp_busy_notifier, msg, dev);
1557         spin_lock(&isotp_notifier_lock);
1558     }
1559     isotp_busy_notifier = NULL;
1560     spin_unlock(&isotp_notifier_lock);
1561     return NOTIFY_DONE;
1562 }
1563 
1564 static int isotp_init(struct sock *sk)
1565 {
1566     struct isotp_sock *so = isotp_sk(sk);
1567 
1568     so->ifindex = 0;
1569     so->bound = 0;
1570 
1571     so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1572     so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1573     so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1574     so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1575     so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1576     so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1577     so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1578     so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1579     so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1580     so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1581     so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1582     so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1583     so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1584 
1585     /* set ll_dl for tx path to similar place as for rx */
1586     so->tx.ll_dl = so->ll.tx_dl;
1587 
1588     so->rx.state = ISOTP_IDLE;
1589     so->tx.state = ISOTP_IDLE;
1590 
1591     hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1592     so->rxtimer.function = isotp_rx_timer_handler;
1593     hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1594     so->txtimer.function = isotp_tx_timer_handler;
1595 
1596     init_waitqueue_head(&so->wait);
1597     spin_lock_init(&so->rx_lock);
1598 
1599     spin_lock(&isotp_notifier_lock);
1600     list_add_tail(&so->notifier, &isotp_notifier_list);
1601     spin_unlock(&isotp_notifier_lock);
1602 
1603     return 0;
1604 }
1605 
1606 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1607                   unsigned long arg)
1608 {
1609     /* no ioctls for socket layer -> hand it down to NIC layer */
1610     return -ENOIOCTLCMD;
1611 }
1612 
1613 static const struct proto_ops isotp_ops = {
1614     .family = PF_CAN,
1615     .release = isotp_release,
1616     .bind = isotp_bind,
1617     .connect = sock_no_connect,
1618     .socketpair = sock_no_socketpair,
1619     .accept = sock_no_accept,
1620     .getname = isotp_getname,
1621     .poll = datagram_poll,
1622     .ioctl = isotp_sock_no_ioctlcmd,
1623     .gettstamp = sock_gettstamp,
1624     .listen = sock_no_listen,
1625     .shutdown = sock_no_shutdown,
1626     .setsockopt = isotp_setsockopt,
1627     .getsockopt = isotp_getsockopt,
1628     .sendmsg = isotp_sendmsg,
1629     .recvmsg = isotp_recvmsg,
1630     .mmap = sock_no_mmap,
1631     .sendpage = sock_no_sendpage,
1632 };
1633 
1634 static struct proto isotp_proto __read_mostly = {
1635     .name = "CAN_ISOTP",
1636     .owner = THIS_MODULE,
1637     .obj_size = sizeof(struct isotp_sock),
1638     .init = isotp_init,
1639 };
1640 
1641 static const struct can_proto isotp_can_proto = {
1642     .type = SOCK_DGRAM,
1643     .protocol = CAN_ISOTP,
1644     .ops = &isotp_ops,
1645     .prot = &isotp_proto,
1646 };
1647 
1648 static struct notifier_block canisotp_notifier = {
1649     .notifier_call = isotp_notifier
1650 };
1651 
1652 static __init int isotp_module_init(void)
1653 {
1654     int err;
1655 
1656     pr_info("can: isotp protocol\n");
1657 
1658     err = can_proto_register(&isotp_can_proto);
1659     if (err < 0)
1660         pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err));
1661     else
1662         register_netdevice_notifier(&canisotp_notifier);
1663 
1664     return err;
1665 }
1666 
1667 static __exit void isotp_module_exit(void)
1668 {
1669     can_proto_unregister(&isotp_can_proto);
1670     unregister_netdevice_notifier(&canisotp_notifier);
1671 }
1672 
1673 module_init(isotp_module_init);
1674 module_exit(isotp_module_exit);
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