Commit e0f3c79c authored by Jeremy Kerr's avatar Jeremy Kerr Committed by Paolo Abeni
Browse files

net: mctp: don't use source cb data when forwarding, ensure pkt_type is set 



In the output path, only check the skb->cb data when we know it's from
a local socket; input packets will have source address information there
instead.

In order to detect when we're forwarding, set skb->pkt_type on
input/output.

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20250702-dev-forwarding-v5-1-1468191da8a4@codeconstruct.com.au


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 05cc60ef

net/mctp/route.c

+12 −1
Original line number Diff line number Diff line
@@ -392,6 +392,9 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) 
	 */

	skb_orphan(skb);



	if (skb->pkt_type == PACKET_OUTGOING)

		skb->pkt_type = PACKET_LOOPBACK;



	/* ensure we have enough data for a header and a type */

	if (skb->len < sizeof(struct mctp_hdr) + 1)

		goto out;
@@ -578,7 +581,13 @@ static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb) 
		return -EMSGSIZE;

	}



	if (cb->ifindex) {

	/* If we're forwarding, we don't want to use the input path's cb,

	 * as it holds the *source* hardware addressing information.

	 *

	 * We will have a PACKET_HOST skb from the dev, or PACKET_OUTGOING

	 * from a socket; only use cb in the latter case.

	 */

	if (skb->pkt_type == PACKET_OUTGOING && cb->ifindex) {

		/* direct route; use the hwaddr we stashed in sendmsg */

		if (cb->halen != skb->dev->addr_len) {

			/* sanity check, sendmsg should have already caught this */
@@ -587,6 +596,7 @@ static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb) 
		}

		daddr = cb->haddr;

	} else {

		skb->pkt_type = PACKET_OUTGOING;

		/* If lookup fails let the device handle daddr==NULL */

		if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0)

			daddr = daddr_buf;
@@ -1032,6 +1042,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, 
		tag = req_tag & MCTP_TAG_MASK;

	}



	skb->pkt_type = PACKET_OUTGOING;

	skb->protocol = htons(ETH_P_MCTP);

	skb->priority = 0;

	skb_reset_transport_header(skb);