[PATCH net-next v7 3/6] can: move ifindex to CAN skb extensions
From: Oliver Hartkopp via B4 Relay <devnull+socketcan.hartkopp.net@kernel.org>
Date: 2026-01-31 13:25:14
Also in:
b4-sent, linux-can, lkml
Subsystem:
can network drivers, can network layer, can-j1939 network layer, the rest · Maintainers:
Marc Kleine-Budde, Vincent Mailhol, Oliver Hartkopp, Robin van der Gracht, Oleksij Rempel, Linus Torvalds
From: Oliver Hartkopp <socketcan@hartkopp.net> When routing CAN frames over different CAN interfaces the interface index skb->iif is overwritten with every single hop. To prevent sending a CAN frame back to its originating (first) incoming CAN interface another ifindex variable is needed, which was stored in can_skb_priv::ifindex. Move the can_skb_priv::ifindex content to can_skb_ext::can_iif. Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> --- drivers/net/can/dev/skb.c | 9 ++++----- net/can/bcm.c | 4 ++-- net/can/gw.c | 2 +- net/can/isotp.c | 6 +++--- net/can/j1939/socket.c | 2 +- net/can/j1939/transport.c | 4 ++-- net/can/raw.c | 2 +- 7 files changed, 14 insertions(+), 15 deletions(-)
diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index c572745565f6..470255fe7367 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c@@ -221,11 +221,11 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) goto out_error_cc; } skb->protocol = htons(ETH_P_CAN); init_can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; *cf = skb_put_zero(skb, sizeof(struct can_frame)); return skb;
@@ -253,11 +253,11 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, goto out_error_fd; } skb->protocol = htons(ETH_P_CANFD); init_can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; *cfd = skb_put_zero(skb, sizeof(struct canfd_frame)); /* set CAN FD flag by default */ (*cfd)->flags = CANFD_FDF;
@@ -292,11 +292,11 @@ struct sk_buff *alloc_canxl_skb(struct net_device *dev, goto out_error_xl; } skb->protocol = htons(ETH_P_CANXL); init_can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = 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;
@@ -342,12 +342,11 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb) csx = can_skb_ext_add(skb); if (!csx) return false; } - can_skb_prv(skb)->ifindex = dev->ifindex; - + csx->can_iif = dev->ifindex; skb->ip_summed = CHECKSUM_UNNECESSARY; /* perform proper loopback on capable devices */ if (dev->flags & IFF_ECHO) skb->pkt_type = PACKET_LOOPBACK;
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 38452069dea8..f102d17e8619 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c@@ -321,11 +321,11 @@ static void bcm_can_tx(struct bcm_op *op) kfree_skb(skb); goto out; } can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; skb_put_data(skb, cf, op->cfsiz); /* send with loopback */ skb->dev = dev;
@@ -1355,11 +1355,11 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk, if (!dev) { kfree_skb(skb); return -ENODEV; } - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; skb->dev = dev; can_skb_set_owner(skb, sk); err = can_send(skb, 1); /* send with loopback */ dev_put(dev);
diff --git a/net/can/gw.c b/net/can/gw.c
index 191afe3b673c..816154a978c1 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c@@ -503,11 +503,11 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data) return; } /* is sending the skb back to the incoming interface not allowed? */ if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && - can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) + csx->can_iif == gwj->dst.dev->ifindex) return; /* clone the given skb, which has not been done in can_rcv() * * When there is at least one modification function activated,
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 94103fe654ff..4a6ce6836b24 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c@@ -235,11 +235,11 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) kfree_skb(nskb); return 1; } can_skb_reserve(nskb); - can_skb_prv(nskb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; nskb->dev = dev; can_skb_set_owner(nskb, sk); ncf = (struct canfd_frame *)nskb->data; skb_put_zero(nskb, so->ll.mtu);
@@ -792,11 +792,11 @@ static void isotp_send_cframe(struct isotp_sock *so) netdev_put(dev, NULL); return; } can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; cf = (struct canfd_frame *)skb->data; skb_put_zero(skb, so->ll.mtu); /* create consecutive frame */
@@ -1028,11 +1028,11 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) netdev_put(dev, NULL); goto err_out_drop; } can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; so->tx.len = size; so->tx.idx = 0; cf = (struct canfd_frame *)skb->data;
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index fc28a7677369..f03bae79354e 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c@@ -902,11 +902,11 @@ static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev, kfree_skb(skb); goto failure; } can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = ndev->ifindex; + csx->can_iif = ndev->ifindex; skb_reserve(skb, offsetof(struct can_frame, data)); ret = memcpy_from_msg(skb_put(skb, size), msg, size); if (ret < 0) goto free_skb;
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 16b4ea5e31ff..88f99a6f5c8e 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c@@ -606,11 +606,11 @@ sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv, return ERR_PTR(-ENOMEM); } skb->dev = priv->ndev; can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = priv->ndev->ifindex; + csx->can_iif = priv->ndev->ifindex; /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data)); /* skb->cb must be large enough to hold a j1939_sk_buff_cb structure */ BUILD_BUG_ON(sizeof(skb->cb) < sizeof(*re_skcb));
@@ -1558,11 +1558,11 @@ j1939_session *j1939_session_fresh_new(struct j1939_priv *priv, return NULL; } skb->dev = priv->ndev; can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = priv->ndev->ifindex; + csx->can_iif = priv->ndev->ifindex; skcb = j1939_skb_to_cb(skb); memcpy(skcb, rel_skcb, sizeof(*skcb)); session = j1939_session_new(priv, skb, size); if (!session) {
diff --git a/net/can/raw.c b/net/can/raw.c
index 03438e9bc535..7c89962ec913 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c@@ -963,11 +963,11 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) kfree_skb(skb); goto put_dev; } can_skb_reserve(skb); - can_skb_prv(skb)->ifindex = dev->ifindex; + csx->can_iif = dev->ifindex; /* fill the skb before testing for valid CAN frames */ err = memcpy_from_msg(skb_put(skb, size), msg, size); if (err < 0) goto free_skb;
--
2.51.0