@@ -380,6 +380,7 @@ sctp_vtag_verify(const struct sctp_chunk *chunk,
if (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)
return 1;
+ chunk->transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
return 0;
}
@@ -1120,14 +1120,9 @@ static inline void sctp_outq_cork(struct sctp_outq *q)
* sctp_input_cb is currently used on rx and sock rx queue
*/
struct sctp_input_cb {
- union {
- struct inet_skb_parm h4;
-#if IS_ENABLED(CONFIG_IPV6)
- struct inet6_skb_parm h6;
-#endif
- } header;
struct sctp_chunk *chunk;
struct sctp_af *af;
+ __be16 encap_port;
};
#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
@@ -1053,6 +1053,7 @@ static struct inet_protosw sctpv6_stream_protosw = {
static int sctp6_rcv(struct sk_buff *skb)
{
+ memset(skb->cb, 0, sizeof(skb->cb));
return sctp_rcv(skb) ? -1 : 0;
}
@@ -843,6 +843,9 @@ static int sctp_ctl_sock_init(struct net *net)
static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
{
+ memset(skb->cb, 0, sizeof(skb->cb));
+ SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
+
skb_set_transport_header(skb, sizeof(struct udphdr));
sctp_rcv(skb);
return 0;
@@ -1139,9 +1142,15 @@ static struct inet_protosw sctp_stream_protosw = {
.flags = SCTP_PROTOSW_FLAG
};
+static int sctp4_rcv(struct sk_buff *skb)
+{
+ memset(skb->cb, 0, sizeof(skb->cb));
+ return sctp_rcv(skb);
+}
+
/* Register with IP layer. */
static const struct net_protocol sctp_protocol = {
- .handler = sctp_rcv,
+ .handler = sctp4_rcv,
.err_handler = sctp_v4_err,
.no_policy = 1,
.netns_ok = 1,
@@ -2321,6 +2321,7 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
* added as the primary transport. The source address seems to
* be a better choice than any of the embedded addresses.
*/
+ asoc->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
goto nomem;
@@ -6268,6 +6268,8 @@ static struct sctp_packet *sctp_ootb_pkt_new(
if (!transport)
goto nomem;
+ transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
+
/* Cache a route for the transport with the chunk's destination as
* the source address.
*/
As rfc6951#section-5.4 says: "After finding the SCTP association (which includes checking the verification tag), the UDP source port MUST be stored as the encapsulation port for the destination address the SCTP packet is received from (see Section 5.1). When a non-encapsulated SCTP packet is received by the SCTP stack, the encapsulation of outgoing packets belonging to the same association and the corresponding destination address MUST be disabled." transport encap_port should be updated by a validated incoming packet's udp src port. We save the udp src port in sctp_input_cb->encap_port, and then update the transport in two places: 1. right after vtag is verified, which is required by RFC, and this allows the existent transports to be updated by the chunks that can only be processed on an asoc. 2. right before processing the 'init' where the transports are added, and this allows building a sctp over udp connection by client with the server not knowing the remote encap port. 3. when processing ootb_pkt and creating the temporary transport for the reply pkt. Note that sctp_input_cb->header is removed, as it's not used any more in sctp. v1->v2: - Change encap_port as __be16 for sctp_input_cb. Signed-off-by: Xin Long <lucien.xin@gmail.com> --- include/net/sctp/sm.h | 1 + include/net/sctp/structs.h | 7 +------ net/sctp/ipv6.c | 1 + net/sctp/protocol.c | 11 ++++++++++- net/sctp/sm_make_chunk.c | 1 + net/sctp/sm_statefuns.c | 2 ++ 6 files changed, 16 insertions(+), 7 deletions(-)