sctp: add udphdr to overhead when udp_port is set (f1bfe8b5) · Commits · 戴 / test

sctp_mtu_payload() is for calculating the frag size before making chunks from a msg. So we should only add udphdr size to overhead when udp socks are listening, as only then sctp can handle the incoming sctp over udp packets and outgoing sctp over udp packets will be possible. Note that we can't do this according to transport->encap_port, as different transports may be set to different values, while the chunks were made before choosing the transport, we could not be able to meet all rfc6951#section-5.6 recommends. v1->v2: - Add udp_port for sctp_sock to avoid a potential race issue, it will be used in xmit path in the next patch. Signed-off-by:

Xin Long <lucien.xin@gmail.com> Acked-by:

Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by:

Jakub Kicinski <kuba@kernel.org>

include/net/sctp/sctp.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -578,10 +578,13 @@ static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
		{
		__u32 overhead = sizeof(struct sctphdr) + extra;

		if (sp)
		if (sp) {
		overhead += sp->pf->af->net_header_len;
		else
		if (sp->udp_port)
		overhead += sizeof(struct udphdr);
		} else {
		overhead += sizeof(struct ipv6hdr);
		}

		if (WARN_ON_ONCE(mtu && mtu <= overhead))
		mtu = overhead;

include/net/sctp/structs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -178,6 +178,7 @@ struct sctp_sock {
		*/
		__u32 hbinterval;

		__be16 udp_port;
		__be16 encap_port;

		/* This is the max_retrans value for new associations. */

net/sctp/socket.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -4928,6 +4928,7 @@ static int sctp_init_sock(struct sock *sk)
		* be modified via SCTP_PEER_ADDR_PARAMS
		*/
		sp->hbinterval = net->sctp.hb_interval;
		sp->udp_port = htons(net->sctp.udp_port);
		sp->encap_port = htons(net->sctp.encap_port);
		sp->pathmaxrxt = net->sctp.max_retrans_path;
		sp->pf_retrans = net->sctp.pf_retrans;

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