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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
* Copyright (C) 2006 Andrey Volkov, Varma Electronics
* Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
*/
#include <linux/can/dev.h>
#include <linux/module.h>
#define MOD_DESC "CAN device driver interface"
MODULE_DESCRIPTION(MOD_DESC);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
/* Local echo of CAN messages
*
* CAN network devices *should* support a local echo functionality
* (see Documentation/networking/can.rst). To test the handling of CAN
* interfaces that do not support the local echo both driver types are
* implemented. In the case that the driver does not support the echo
* the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
* to perform the echo as a fallback solution.
*/
void can_flush_echo_skb(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
int i;
for (i = 0; i < priv->echo_skb_max; i++) {
if (priv->echo_skb[i]) {
kfree_skb(priv->echo_skb[i]);
priv->echo_skb[i] = NULL;
stats->tx_dropped++;
stats->tx_aborted_errors++;
}
}
}
/* Put the skb on the stack to be looped backed locally lateron
*
* The function is typically called in the start_xmit function
* of the device driver. The driver must protect access to
* priv->echo_skb, if necessary.
*/
int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
unsigned int idx, unsigned int frame_len)
{
struct can_priv *priv = netdev_priv(dev);
if (idx >= priv->echo_skb_max) {
netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
__func__, idx, priv->echo_skb_max);
return -EINVAL;
}
/* check flag whether this packet has to be looped back */
if (!(dev->flags & IFF_ECHO) ||
(skb->protocol != htons(ETH_P_CAN) &&
skb->protocol != htons(ETH_P_CANFD) &&
skb->protocol != htons(ETH_P_CANXL))) {
kfree_skb(skb);
return 0;
}
if (!priv->echo_skb[idx]) {
skb = can_create_echo_skb(skb);
if (!skb)
return -ENOMEM;
/* make settings for echo to reduce code in irq context */
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->dev = dev;
/* save frame_len to reuse it when transmission is completed */
can_skb_prv(skb)->frame_len = frame_len;
if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
skb_tx_timestamp(skb);
/* save this skb for tx interrupt echo handling */
priv->echo_skb[idx] = skb;
} else {
/* locking problem with netif_stop_queue() ?? */
netdev_err(dev, "%s: BUG! echo_skb %d is occupied!\n", __func__, idx);
kfree_skb(skb);
return -EBUSY;
}
return 0;
}
EXPORT_SYMBOL_GPL(can_put_echo_skb);
struct sk_buff *
__can_get_echo_skb(struct net_device *dev, unsigned int idx,
unsigned int *len_ptr, unsigned int *frame_len_ptr)
{
struct can_priv *priv = netdev_priv(dev);
if (idx >= priv->echo_skb_max) {
netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
__func__, idx, priv->echo_skb_max);
return NULL;
}
if (priv->echo_skb[idx]) {
/* Using "struct canfd_frame::len" for the frame
* length is supported on both CAN and CANFD frames.
*/
struct sk_buff *skb = priv->echo_skb[idx];
struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
if (skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)
skb_tstamp_tx(skb, skb_hwtstamps(skb));
/* get the real payload length for netdev statistics */
*len_ptr = can_skb_get_data_len(skb);
if (frame_len_ptr)
*frame_len_ptr = can_skb_priv->frame_len;
priv->echo_skb[idx] = NULL;
if (skb->pkt_type == PACKET_LOOPBACK) {
skb->pkt_type = PACKET_BROADCAST;
} else {
dev_consume_skb_any(skb);
return NULL;
}
return skb;
}
return NULL;
}
/* Get the skb from the stack and loop it back locally
*
* The function is typically called when the TX done interrupt
* is handled in the device driver. The driver must protect
* access to priv->echo_skb, if necessary.
*/
unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx,
unsigned int *frame_len_ptr)
{
struct sk_buff *skb;
unsigned int len;
skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
if (!skb)
return 0;
skb_get(skb);
if (netif_rx(skb) == NET_RX_SUCCESS)
dev_consume_skb_any(skb);
else
dev_kfree_skb_any(skb);
return len;
}
EXPORT_SYMBOL_GPL(can_get_echo_skb);
/* Remove the skb from the stack and free it.
*
* The function is typically called when TX failed.
*/
void can_free_echo_skb(struct net_device *dev, unsigned int idx,
unsigned int *frame_len_ptr)
{
struct can_priv *priv = netdev_priv(dev);
if (idx >= priv->echo_skb_max) {
netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
__func__, idx, priv->echo_skb_max);
return;
}
if (priv->echo_skb[idx]) {
struct sk_buff *skb = priv->echo_skb[idx];
struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
if (frame_len_ptr)
*frame_len_ptr = can_skb_priv->frame_len;
dev_kfree_skb_any(skb);
priv->echo_skb[idx] = NULL;
}
}
EXPORT_SYMBOL_GPL(can_free_echo_skb);
/* fill common values for CAN sk_buffs */
static void init_can_skb_reserve(struct sk_buff *skb)
{
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
can_skb_reserve(skb);
can_skb_prv(skb)->skbcnt = 0;
}
struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
{
struct sk_buff *skb;
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
sizeof(struct can_frame));
if (unlikely(!skb)) {
*cf = NULL;
return NULL;
}
skb->protocol = htons(ETH_P_CAN);
init_can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
*cf = skb_put_zero(skb, sizeof(struct can_frame));
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_skb);
struct sk_buff *alloc_canfd_skb(struct net_device *dev,
struct canfd_frame **cfd)
{
struct sk_buff *skb;
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
sizeof(struct canfd_frame));
if (unlikely(!skb)) {
*cfd = NULL;
return NULL;
}
skb->protocol = htons(ETH_P_CANFD);
init_can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
/* set CAN FD flag by default */
(*cfd)->flags = CANFD_FDF;
return skb;
}
EXPORT_SYMBOL_GPL(alloc_canfd_skb);
struct sk_buff *alloc_canxl_skb(struct net_device *dev,
struct canxl_frame **cxl,
unsigned int data_len)
{
struct sk_buff *skb;
if (data_len < CANXL_MIN_DLEN || data_len > CANXL_MAX_DLEN)
goto out_error;
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
CANXL_HDR_SIZE + data_len);
if (unlikely(!skb))
goto out_error;
skb->protocol = htons(ETH_P_CANXL);
init_can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
*cxl = skb_put_zero(skb, CANXL_HDR_SIZE + data_len);
/* set CAN XL flag and length information by default */
(*cxl)->flags = CANXL_XLF;
(*cxl)->len = data_len;
return skb;
out_error:
*cxl = NULL;
return NULL;
}
EXPORT_SYMBOL_GPL(alloc_canxl_skb);
struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
{
struct sk_buff *skb;
skb = alloc_can_skb(dev, cf);
if (unlikely(!skb))
return NULL;
(*cf)->can_id = CAN_ERR_FLAG;
(*cf)->len = CAN_ERR_DLC;
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_err_skb);
/* Check for outgoing skbs that have not been created by the CAN subsystem */
static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
{
/* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
return false;
/* af_packet does not apply CAN skb specific settings */
if (skb->ip_summed == CHECKSUM_NONE) {
/* init headroom */
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
skb->ip_summed = CHECKSUM_UNNECESSARY;
/* perform proper loopback on capable devices */
if (dev->flags & IFF_ECHO)
skb->pkt_type = PACKET_LOOPBACK;
else
skb->pkt_type = PACKET_HOST;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
/* set CANFD_FDF flag for CAN FD frames */
if (can_is_canfd_skb(skb)) {
struct canfd_frame *cfd;
cfd = (struct canfd_frame *)skb->data;
cfd->flags |= CANFD_FDF;
}
}
return true;
}
/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
{
switch (ntohs(skb->protocol)) {
case ETH_P_CAN:
if (!can_is_can_skb(skb))
goto inval_skb;
break;
case ETH_P_CANFD:
if (!can_is_canfd_skb(skb))
goto inval_skb;
break;
case ETH_P_CANXL:
if (!can_is_canxl_skb(skb))
goto inval_skb;
break;
default:
goto inval_skb;
}
if (!can_skb_headroom_valid(dev, skb))
goto inval_skb;
return false;
inval_skb:
kfree_skb(skb);
dev->stats.tx_dropped++;
return true;
}
EXPORT_SYMBOL_GPL(can_dropped_invalid_skb);