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isotp.c
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isotp.c
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// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/* isotp.c - ISO 15765-2 CAN transport protocol for protocol family CAN
*
* This implementation does not provide ISO-TP specific return values to the
* userspace.
*
* - RX path timeout of data reception leads to -ETIMEDOUT
* - RX path SN mismatch leads to -EILSEQ
* - RX path data reception with wrong padding leads to -EBADMSG
* - TX path flowcontrol reception timeout leads to -ECOMM
* - TX path flowcontrol reception overflow leads to -EMSGSIZE
* - TX path flowcontrol reception with wrong layout/padding leads to -EBADMSG
* - when a transfer (tx) is on the run the next write() blocks until it's done
* - use CAN_ISOTP_WAIT_TX_DONE flag to block the caller until the PDU is sent
* - as we have static buffers the check whether the PDU fits into the buffer
* is done at FF reception time (no support for sending 'wait frames')
* - take care of the tx-queue-len as traffic shaping is still on the TODO list
*
* Copyright (c) 2020 Volkswagen Group Electronic Research
* 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 name of Volkswagen nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
* The provided data structures and external interfaces from this code
* are not restricted to be used by modules with a GPL compatible license.
*
* 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/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/hrtimer.h>
#include <linux/wait.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
#include <linux/can/skb.h>
#include <linux/can/isotp.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/net_namespace.h>
MODULE_DESCRIPTION("PF_CAN isotp 15765-2:2016 protocol");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
MODULE_ALIAS("can-proto-6");
#define ISOTP_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp)
#define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
(CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
(CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
/* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
* take full 32 bit values (4 Gbyte). We would need some good concept to handle
* this between user space and kernel space. For now increase the static buffer
* to something about 8 kbyte to be able to test this new functionality.
*/
#define MAX_MSG_LENGTH 8200
/* N_PCI type values in bits 7-4 of N_PCI bytes */
#define N_PCI_SF 0x00 /* single frame */
#define N_PCI_FF 0x10 /* first frame */
#define N_PCI_CF 0x20 /* consecutive frame */
#define N_PCI_FC 0x30 /* flow control */
#define N_PCI_SZ 1 /* size of the PCI byte #1 */
#define SF_PCI_SZ4 1 /* size of SingleFrame PCI including 4 bit SF_DL */
#define SF_PCI_SZ8 2 /* size of SingleFrame PCI including 8 bit SF_DL */
#define FF_PCI_SZ12 2 /* size of FirstFrame PCI including 12 bit FF_DL */
#define FF_PCI_SZ32 6 /* size of FirstFrame PCI including 32 bit FF_DL */
#define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
#define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
/* Flow Status given in FC frame */
#define ISOTP_FC_CTS 0 /* clear to send */
#define ISOTP_FC_WT 1 /* wait */
#define ISOTP_FC_OVFLW 2 /* overflow */
enum {
ISOTP_IDLE = 0,
ISOTP_WAIT_FIRST_FC,
ISOTP_WAIT_FC,
ISOTP_WAIT_DATA,
ISOTP_SENDING
};
struct tpcon {
unsigned int idx;
unsigned int len;
u32 state;
u8 bs;
u8 sn;
u8 ll_dl;
u8 buf[MAX_MSG_LENGTH + 1];
};
struct isotp_sock {
struct sock sk;
int bound;
int ifindex;
canid_t txid;
canid_t rxid;
ktime_t tx_gap;
ktime_t lastrxcf_tstamp;
struct hrtimer rxtimer, txtimer;
struct can_isotp_options opt;
struct can_isotp_fc_options rxfc, txfc;
struct can_isotp_ll_options ll;
u32 frame_txtime;
u32 force_tx_stmin;
u32 force_rx_stmin;
struct tpcon rx, tx;
struct list_head notifier;
wait_queue_head_t wait;
spinlock_t rx_lock; /* protect single thread state machine */
};
static LIST_HEAD(isotp_notifier_list);
static DEFINE_SPINLOCK(isotp_notifier_lock);
static struct isotp_sock *isotp_busy_notifier;
static inline struct isotp_sock *isotp_sk(const struct sock *sk)
{
return (struct isotp_sock *)sk;
}
static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
{
struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
rxtimer);
struct sock *sk = &so->sk;
if (so->rx.state == ISOTP_WAIT_DATA) {
/* we did not get new data frames in time */
/* report 'connection timed out' */
sk->sk_err = ETIMEDOUT;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
/* reset rx state */
so->rx.state = ISOTP_IDLE;
}
return HRTIMER_NORESTART;
}
static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
{
struct net_device *dev;
struct sk_buff *nskb;
struct canfd_frame *ncf;
struct isotp_sock *so = isotp_sk(sk);
int can_send_ret;
nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any());
if (!nskb)
return 1;
dev = dev_get_by_index(sock_net(sk), so->ifindex);
if (!dev) {
kfree_skb(nskb);
return 1;
}
can_skb_reserve(nskb);
can_skb_prv(nskb)->ifindex = dev->ifindex;
can_skb_prv(nskb)->skbcnt = 0;
nskb->dev = dev;
can_skb_set_owner(nskb, sk);
ncf = (struct canfd_frame *)nskb->data;
skb_put_zero(nskb, so->ll.mtu);
/* create & send flow control reply */
ncf->can_id = so->txid;
if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
ncf->len = CAN_MAX_DLEN;
} else {
ncf->len = ae + FC_CONTENT_SZ;
}
ncf->data[ae] = N_PCI_FC | flowstatus;
ncf->data[ae + 1] = so->rxfc.bs;
ncf->data[ae + 2] = so->rxfc.stmin;
if (ae)
ncf->data[0] = so->opt.ext_address;
ncf->flags = so->ll.tx_flags;
can_send_ret = can_send(nskb, 1);
if (can_send_ret)
pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
__func__, ERR_PTR(can_send_ret));
dev_put(dev);
/* reset blocksize counter */
so->rx.bs = 0;
/* reset last CF frame rx timestamp for rx stmin enforcement */
so->lastrxcf_tstamp = ktime_set(0, 0);
/* start rx timeout watchdog */
hrtimer_start(&so->rxtimer, ktime_set(1, 0), HRTIMER_MODE_REL_SOFT);
return 0;
}
static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
{
struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
memset(addr, 0, sizeof(*addr));
addr->can_family = AF_CAN;
addr->can_ifindex = skb->dev->ifindex;
if (sock_queue_rcv_skb(sk, skb) < 0)
kfree_skb(skb);
}
static u8 padlen(u8 datalen)
{
static const u8 plen[] = {
8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
12, 12, 12, 12, /* 9 - 12 */
16, 16, 16, 16, /* 13 - 16 */
20, 20, 20, 20, /* 17 - 20 */
24, 24, 24, 24, /* 21 - 24 */
32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
};
if (datalen > 48)
return 64;
return plen[datalen];
}
/* check for length optimization and return 1/true when the check fails */
static int check_optimized(struct canfd_frame *cf, int start_index)
{
/* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
* padding would start at this point. E.g. if the padding would
* start at cf.data[7] cf->len has to be 7 to be optimal.
* Note: The data[] index starts with zero.
*/
if (cf->len <= CAN_MAX_DLEN)
return (cf->len != start_index);
/* This relation is also valid in the non-linear DLC range, where
* we need to take care of the minimal next possible CAN_DL.
* The correct check would be (padlen(cf->len) != padlen(start_index)).
* But as cf->len can only take discrete values from 12, .., 64 at this
* point the padlen(cf->len) is always equal to cf->len.
*/
return (cf->len != padlen(start_index));
}
/* check padding and return 1/true when the check fails */
static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
int start_index, u8 content)
{
int i;
/* no RX_PADDING value => check length of optimized frame length */
if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
return check_optimized(cf, start_index);
/* no valid test against empty value => ignore frame */
return 1;
}
/* check datalength of correctly padded CAN frame */
if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
cf->len != padlen(cf->len))
return 1;
/* check padding content */
if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
for (i = start_index; i < cf->len; i++)
if (cf->data[i] != content)
return 1;
}
return 0;
}
static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
{
struct sock *sk = &so->sk;
if (so->tx.state != ISOTP_WAIT_FC &&
so->tx.state != ISOTP_WAIT_FIRST_FC)
return 0;
hrtimer_cancel(&so->txtimer);
if ((cf->len < ae + FC_CONTENT_SZ) ||
((so->opt.flags & ISOTP_CHECK_PADDING) &&
check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
/* malformed PDU - report 'not a data message' */
sk->sk_err = EBADMSG;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
return 1;
}
/* get communication parameters only from the first FC frame */
if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
so->txfc.bs = cf->data[ae + 1];
so->txfc.stmin = cf->data[ae + 2];
/* fix wrong STmin values according spec */
if (so->txfc.stmin > 0x7F &&
(so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
so->txfc.stmin = 0x7F;
so->tx_gap = ktime_set(0, 0);
/* add transmission time for CAN frame N_As */
so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
/* add waiting time for consecutive frames N_Cs */
if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
so->tx_gap = ktime_add_ns(so->tx_gap,
so->force_tx_stmin);
else if (so->txfc.stmin < 0x80)
so->tx_gap = ktime_add_ns(so->tx_gap,
so->txfc.stmin * 1000000);
else
so->tx_gap = ktime_add_ns(so->tx_gap,
(so->txfc.stmin - 0xF0)
* 100000);
so->tx.state = ISOTP_WAIT_FC;
}
switch (cf->data[ae] & 0x0F) {
case ISOTP_FC_CTS:
so->tx.bs = 0;
so->tx.state = ISOTP_SENDING;
/* start cyclic timer for sending CF frame */
hrtimer_start(&so->txtimer, so->tx_gap,
HRTIMER_MODE_REL_SOFT);
break;
case ISOTP_FC_WT:
/* start timer to wait for next FC frame */
hrtimer_start(&so->txtimer, ktime_set(1, 0),
HRTIMER_MODE_REL_SOFT);
break;
case ISOTP_FC_OVFLW:
/* overflow on receiver side - report 'message too long' */
sk->sk_err = EMSGSIZE;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
fallthrough;
default:
/* stop this tx job */
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
}
return 0;
}
static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
struct sk_buff *skb, int len)
{
struct isotp_sock *so = isotp_sk(sk);
struct sk_buff *nskb;
hrtimer_cancel(&so->rxtimer);
so->rx.state = ISOTP_IDLE;
if (!len || len > cf->len - pcilen)
return 1;
if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
/* malformed PDU - report 'not a data message' */
sk->sk_err = EBADMSG;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
return 1;
}
nskb = alloc_skb(len, gfp_any());
if (!nskb)
return 1;
memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
nskb->tstamp = skb->tstamp;
nskb->dev = skb->dev;
isotp_rcv_skb(nskb, sk);
return 0;
}
static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
{
struct isotp_sock *so = isotp_sk(sk);
int i;
int off;
int ff_pci_sz;
hrtimer_cancel(&so->rxtimer);
so->rx.state = ISOTP_IDLE;
/* get the used sender LL_DL from the (first) CAN frame data length */
so->rx.ll_dl = padlen(cf->len);
/* the first frame has to use the entire frame up to LL_DL length */
if (cf->len != so->rx.ll_dl)
return 1;
/* get the FF_DL */
so->rx.len = (cf->data[ae] & 0x0F) << 8;
so->rx.len += cf->data[ae + 1];
/* Check for FF_DL escape sequence supporting 32 bit PDU length */
if (so->rx.len) {
ff_pci_sz = FF_PCI_SZ12;
} else {
/* FF_DL = 0 => get real length from next 4 bytes */
so->rx.len = cf->data[ae + 2] << 24;
so->rx.len += cf->data[ae + 3] << 16;
so->rx.len += cf->data[ae + 4] << 8;
so->rx.len += cf->data[ae + 5];
ff_pci_sz = FF_PCI_SZ32;
}
/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
return 1;
if (so->rx.len > MAX_MSG_LENGTH) {
/* send FC frame with overflow status */
isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
return 1;
}
/* copy the first received data bytes */
so->rx.idx = 0;
for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
so->rx.buf[so->rx.idx++] = cf->data[i];
/* initial setup for this pdu reception */
so->rx.sn = 1;
so->rx.state = ISOTP_WAIT_DATA;
/* no creation of flow control frames */
if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
return 0;
/* send our first FC frame */
isotp_send_fc(sk, ae, ISOTP_FC_CTS);
return 0;
}
static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
struct sk_buff *skb)
{
struct isotp_sock *so = isotp_sk(sk);
struct sk_buff *nskb;
int i;
if (so->rx.state != ISOTP_WAIT_DATA)
return 0;
/* drop if timestamp gap is less than force_rx_stmin nano secs */
if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
so->force_rx_stmin)
return 0;
so->lastrxcf_tstamp = skb->tstamp;
}
hrtimer_cancel(&so->rxtimer);
/* CFs are never longer than the FF */
if (cf->len > so->rx.ll_dl)
return 1;
/* CFs have usually the LL_DL length */
if (cf->len < so->rx.ll_dl) {
/* this is only allowed for the last CF */
if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
return 1;
}
if ((cf->data[ae] & 0x0F) != so->rx.sn) {
/* wrong sn detected - report 'illegal byte sequence' */
sk->sk_err = EILSEQ;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
/* reset rx state */
so->rx.state = ISOTP_IDLE;
return 1;
}
so->rx.sn++;
so->rx.sn %= 16;
for (i = ae + N_PCI_SZ; i < cf->len; i++) {
so->rx.buf[so->rx.idx++] = cf->data[i];
if (so->rx.idx >= so->rx.len)
break;
}
if (so->rx.idx >= so->rx.len) {
/* we are done */
so->rx.state = ISOTP_IDLE;
if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
/* malformed PDU - report 'not a data message' */
sk->sk_err = EBADMSG;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
return 1;
}
nskb = alloc_skb(so->rx.len, gfp_any());
if (!nskb)
return 1;
memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
so->rx.len);
nskb->tstamp = skb->tstamp;
nskb->dev = skb->dev;
isotp_rcv_skb(nskb, sk);
return 0;
}
/* perform blocksize handling, if enabled */
if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
/* start rx timeout watchdog */
hrtimer_start(&so->rxtimer, ktime_set(1, 0),
HRTIMER_MODE_REL_SOFT);
return 0;
}
/* no creation of flow control frames */
if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
return 0;
/* we reached the specified blocksize so->rxfc.bs */
isotp_send_fc(sk, ae, ISOTP_FC_CTS);
return 0;
}
static void isotp_rcv(struct sk_buff *skb, void *data)
{
struct sock *sk = (struct sock *)data;
struct isotp_sock *so = isotp_sk(sk);
struct canfd_frame *cf;
int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
u8 n_pci_type, sf_dl;
/* Strictly receive only frames with the configured MTU size
* => clear separation of CAN2.0 / CAN FD transport channels
*/
if (skb->len != so->ll.mtu)
return;
cf = (struct canfd_frame *)skb->data;
/* if enabled: check reception of my configured extended address */
if (ae && cf->data[0] != so->opt.rx_ext_address)
return;
n_pci_type = cf->data[ae] & 0xF0;
/* Make sure the state changes and data structures stay consistent at
* CAN frame reception time. This locking is not needed in real world
* use cases but the inconsistency can be triggered with syzkaller.
*/
spin_lock(&so->rx_lock);
if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
/* check rx/tx path half duplex expectations */
if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
(so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
goto out_unlock;
}
switch (n_pci_type) {
case N_PCI_FC:
/* tx path: flow control frame containing the FC parameters */
isotp_rcv_fc(so, cf, ae);
break;
case N_PCI_SF:
/* rx path: single frame
*
* As we do not have a rx.ll_dl configuration, we can only test
* if the CAN frames payload length matches the LL_DL == 8
* requirements - no matter if it's CAN 2.0 or CAN FD
*/
/* get the SF_DL from the N_PCI byte */
sf_dl = cf->data[ae] & 0x0F;
if (cf->len <= CAN_MAX_DLEN) {
isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
} else {
if (skb->len == CANFD_MTU) {
/* We have a CAN FD frame and CAN_DL is greater than 8:
* Only frames with the SF_DL == 0 ESC value are valid.
*
* If so take care of the increased SF PCI size
* (SF_PCI_SZ8) to point to the message content behind
* the extended SF PCI info and get the real SF_DL
* length value from the formerly first data byte.
*/
if (sf_dl == 0)
isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
cf->data[SF_PCI_SZ4 + ae]);
}
}
break;
case N_PCI_FF:
/* rx path: first frame */
isotp_rcv_ff(sk, cf, ae);
break;
case N_PCI_CF:
/* rx path: consecutive frame */
isotp_rcv_cf(sk, cf, ae, skb);
break;
}
out_unlock:
spin_unlock(&so->rx_lock);
}
static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
int ae, int off)
{
int pcilen = N_PCI_SZ + ae + off;
int space = so->tx.ll_dl - pcilen;
int num = min_t(int, so->tx.len - so->tx.idx, space);
int i;
cf->can_id = so->txid;
cf->len = num + pcilen;
if (num < space) {
if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
/* user requested padding */
cf->len = padlen(cf->len);
memset(cf->data, so->opt.txpad_content, cf->len);
} else if (cf->len > CAN_MAX_DLEN) {
/* mandatory padding for CAN FD frames */
cf->len = padlen(cf->len);
memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
cf->len);
}
}
for (i = 0; i < num; i++)
cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
if (ae)
cf->data[0] = so->opt.ext_address;
}
static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
int ae)
{
int i;
int ff_pci_sz;
cf->can_id = so->txid;
cf->len = so->tx.ll_dl;
if (ae)
cf->data[0] = so->opt.ext_address;
/* create N_PCI bytes with 12/32 bit FF_DL data length */
if (so->tx.len > 4095) {
/* use 32 bit FF_DL notation */
cf->data[ae] = N_PCI_FF;
cf->data[ae + 1] = 0;
cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
ff_pci_sz = FF_PCI_SZ32;
} else {
/* use 12 bit FF_DL notation */
cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
ff_pci_sz = FF_PCI_SZ12;
}
/* add first data bytes depending on ae */
for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
cf->data[i] = so->tx.buf[so->tx.idx++];
so->tx.sn = 1;
so->tx.state = ISOTP_WAIT_FIRST_FC;
}
static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
{
struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
txtimer);
struct sock *sk = &so->sk;
struct sk_buff *skb;
struct net_device *dev;
struct canfd_frame *cf;
enum hrtimer_restart restart = HRTIMER_NORESTART;
int can_send_ret;
int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
switch (so->tx.state) {
case ISOTP_WAIT_FC:
case ISOTP_WAIT_FIRST_FC:
/* we did not get any flow control frame in time */
/* report 'communication error on send' */
sk->sk_err = ECOMM;
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
/* reset tx state */
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
break;
case ISOTP_SENDING:
/* push out the next segmented pdu */
dev = dev_get_by_index(sock_net(sk), so->ifindex);
if (!dev)
break;
isotp_tx_burst:
skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv),
GFP_ATOMIC);
if (!skb) {
dev_put(dev);
break;
}
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
cf = (struct canfd_frame *)skb->data;
skb_put_zero(skb, so->ll.mtu);
/* create consecutive frame */
isotp_fill_dataframe(cf, so, ae, 0);
/* place consecutive frame N_PCI in appropriate index */
cf->data[ae] = N_PCI_CF | so->tx.sn++;
so->tx.sn %= 16;
so->tx.bs++;
cf->flags = so->ll.tx_flags;
skb->dev = dev;
can_skb_set_owner(skb, sk);
can_send_ret = can_send(skb, 1);
if (can_send_ret) {
pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
__func__, ERR_PTR(can_send_ret));
if (can_send_ret == -ENOBUFS)
pr_notice_once("can-isotp: tx queue is full, increasing txqueuelen may prevent this error\n");
}
if (so->tx.idx >= so->tx.len) {
/* we are done */
so->tx.state = ISOTP_IDLE;
dev_put(dev);
wake_up_interruptible(&so->wait);
break;
}
if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
/* stop and wait for FC */
so->tx.state = ISOTP_WAIT_FC;
dev_put(dev);
hrtimer_set_expires(&so->txtimer,
ktime_add(ktime_get(),
ktime_set(1, 0)));
restart = HRTIMER_RESTART;
break;
}
/* no gap between data frames needed => use burst mode */
if (!so->tx_gap)
goto isotp_tx_burst;
/* start timer to send next data frame with correct delay */
dev_put(dev);
hrtimer_set_expires(&so->txtimer,
ktime_add(ktime_get(), so->tx_gap));
restart = HRTIMER_RESTART;
break;
default:
WARN_ON_ONCE(1);
}
return restart;
}
static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
{
struct sock *sk = sock->sk;
struct isotp_sock *so = isotp_sk(sk);
u32 old_state = so->tx.state;
struct sk_buff *skb;
struct net_device *dev;
struct canfd_frame *cf;
int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
s64 hrtimer_sec = 0;
int off;
int err;
if (!so->bound)
return -EADDRNOTAVAIL;
/* we do not support multiple buffers - for now */
if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE ||
wq_has_sleeper(&so->wait)) {
if (msg->msg_flags & MSG_DONTWAIT) {
err = -EAGAIN;
goto err_out;
}
/* wait for complete transmission of current pdu */
err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
if (err)
goto err_out;
}
if (!size || size > MAX_MSG_LENGTH) {
err = -EINVAL;
goto err_out_drop;
}
/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
/* does the given data fit into a single frame for SF_BROADCAST? */
if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) &&
(size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
err = -EINVAL;
goto err_out_drop;
}
err = memcpy_from_msg(so->tx.buf, msg, size);
if (err < 0)
goto err_out_drop;
dev = dev_get_by_index(sock_net(sk), so->ifindex);
if (!dev) {
err = -ENXIO;
goto err_out_drop;
}
skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
msg->msg_flags & MSG_DONTWAIT, &err);
if (!skb) {
dev_put(dev);
goto err_out_drop;
}
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
so->tx.len = size;
so->tx.idx = 0;
cf = (struct canfd_frame *)skb->data;
skb_put_zero(skb, so->ll.mtu);
/* check for single frame transmission depending on TX_DL */
if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
/* The message size generally fits into a SingleFrame - good.
*
* SF_DL ESC offset optimization:
*
* When TX_DL is greater 8 but the message would still fit
* into a 8 byte CAN frame, we can omit the offset.
* This prevents a protocol caused length extension from
* CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
*/
if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
off = 0;
isotp_fill_dataframe(cf, so, ae, off);
/* place single frame N_PCI w/o length in appropriate index */
cf->data[ae] = N_PCI_SF;
/* place SF_DL size value depending on the SF_DL ESC offset */
if (off)
cf->data[SF_PCI_SZ4 + ae] = size;
else
cf->data[ae] |= size;
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
/* don't enable wait queue for a single frame transmission */
wait_tx_done = 0;
} else {
/* send first frame and wait for FC */
isotp_create_fframe(cf, so, ae);
/* start timeout for FC */
hrtimer_sec = 1;
hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
HRTIMER_MODE_REL_SOFT);
}
/* send the first or only CAN frame */
cf->flags = so->ll.tx_flags;
skb->dev = dev;
skb->sk = sk;
err = can_send(skb, 1);
dev_put(dev);
if (err) {
pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
__func__, ERR_PTR(err));
/* no transmission -> no timeout monitoring */
if (hrtimer_sec)
hrtimer_cancel(&so->txtimer);
goto err_out_drop;
}
if (wait_tx_done) {
/* wait for complete transmission of current pdu */
wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
if (sk->sk_err)
return -sk->sk_err;
}
return size;