[PATCH net-next v3 04/14] net: mctp: separate cb from direct-addressing routing
From: Jeremy Kerr <jk@codeconstruct.com.au>
Date: 2025-06-25 07:35:07
Subsystem:
management component transport protocol (mctp), networking [general], the rest · Maintainers:
Jeremy Kerr, Matt Johnston, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Now that we have the dst->haddr populated by sendmsg (when extended addressing is in use), we no longer need to stash the link-layer address in the skb->cb. Instead, only use skb->cb for incoming lladdr data. While we're at it: remove cb->src, as was never used. Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> --- include/net/mctp.h | 4 ++-- net/mctp/af_mctp.c | 3 +-- net/mctp/route.c | 21 +++++---------------- 3 files changed, 8 insertions(+), 20 deletions(-)
diff --git a/include/net/mctp.h b/include/net/mctp.h
index 6c9c5c48f59a1bf45f9c9d274a3ca2b633e96c75..b3af0690f60749a9bf9f489c7118c82cfd9d577e 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h@@ -183,8 +183,8 @@ struct mctp_sk_key { struct mctp_skb_cb { unsigned int magic; unsigned int net; - int ifindex; /* extended/direct addressing if set */ - mctp_eid_t src; + /* fields below provide extended addressing for ingress to recvmsg() */ + int ifindex; unsigned char halen; unsigned char haddr[MAX_ADDR_LEN]; };
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index ca66521435b10c2299b82ed64718ddc98f1f07f3..1141a4e33aaaabef4b58a5942dbe2847f2b7fcdd 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c@@ -134,8 +134,7 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, extaddr, msg->msg_name); - if (!mctp_sockaddr_ext_is_ok(extaddr) || - extaddr->smctp_halen > sizeof(cb->haddr)) { + if (!mctp_sockaddr_ext_is_ok(extaddr)) { rc = -EINVAL; goto err_free; }
diff --git a/net/mctp/route.c b/net/mctp/route.c
index e11bf1c1e383cc251c5b6e2852d3756f706956c7..42d80a9f21d6a054375156e3de21be72a187c6fc 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c@@ -561,35 +561,28 @@ static int mctp_dst_input(struct mctp_dst *dst, struct sk_buff *skb) static int mctp_dst_output(struct mctp_dst *dst, struct sk_buff *skb) { - struct mctp_skb_cb *cb = mctp_cb(skb); struct mctp_hdr *hdr = mctp_hdr(skb); char daddr_buf[MAX_ADDR_LEN]; char *daddr = NULL; int rc; skb->protocol = htons(ETH_P_MCTP); + skb->pkt_type = PACKET_OUTGOING; if (skb->len > dst->mtu) { kfree_skb(skb); return -EMSGSIZE; } - /* 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) { + /* direct route; use the hwaddr we stashed in sendmsg */ + if (dst->halen) { + if (dst->halen != skb->dev->addr_len) { /* sanity check, sendmsg should have already caught this */ kfree_skb(skb); return -EMSGSIZE; } - daddr = cb->haddr; + daddr = dst->haddr; } else { - skb->pkt_type = PACKET_OUTGOING; /* If lookup fails let the device handle daddr==NULL */ if (mctp_neigh_lookup(dst->dev, hdr->dest, daddr_buf) == 0) daddr = daddr_buf;
@@ -1004,7 +997,6 @@ int mctp_local_output(struct sock *sk, struct mctp_dst *dst, struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag) { struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); - struct mctp_skb_cb *cb = mctp_cb(skb); struct mctp_sk_key *key; struct mctp_hdr *hdr; unsigned long flags;
@@ -1059,9 +1051,6 @@ int mctp_local_output(struct sock *sk, struct mctp_dst *dst, skb_reset_network_header(skb); skb->dev = dst->dev->dev; - /* cb->net will have been set on initial ingress */ - cb->src = saddr; - /* set up common header fields */ hdr = mctp_hdr(skb); hdr->ver = 1;
--
2.39.5