net: sctp: implement rfc6458, 5.3.5. SCTP_RCVINFO cmsg support
This patch implements section 5.3.5. of RFC6458, that is, support
for 'SCTP Receive Information Structure' (SCTP_RCVINFO) which is
placed into ancillary data cmsghdr structure for each recvmsg()
call.
This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
level by setting an int value with 1/0 for SCTP_RECVRCVINFO in user
space applications as per RFC6458, section 8.1.29.
The sctp_rcvinfo structure is defined as per RFC as below ...
struct sctp_rcvinfo {
uint16_t rcv_sid;
uint16_t rcv_ssn;
uint16_t rcv_flags;
<-- 2 bytes hole -->
uint32_t rcv_ppid;
uint32_t rcv_tsn;
uint32_t rcv_cumtsn;
uint32_t rcv_context;
sctp_assoc_t rcv_assoc_id;
};
... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_RCVINFO, while cmsg_data[] contains struct sctp_rcvinfo.
An sctp_rcvinfo item always corresponds to the data in msg_iov.
Joint work with Daniel Borkmann.
Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index b6842fd..b31f365 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -886,6 +886,31 @@
sizeof(sinfo), &sinfo);
}
+/* RFC6458, Section 5.3.5 SCTP Receive Information Structure
+ * (SCTP_SNDRCV)
+ */
+void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
+ struct msghdr *msghdr)
+{
+ struct sctp_rcvinfo rinfo;
+
+ if (sctp_ulpevent_is_notification(event))
+ return;
+
+ memset(&rinfo, 0, sizeof(struct sctp_rcvinfo));
+ rinfo.rcv_sid = event->stream;
+ rinfo.rcv_ssn = event->ssn;
+ rinfo.rcv_ppid = event->ppid;
+ rinfo.rcv_flags = event->flags;
+ rinfo.rcv_tsn = event->tsn;
+ rinfo.rcv_cumtsn = event->cumtsn;
+ rinfo.rcv_assoc_id = sctp_assoc2id(event->asoc);
+ rinfo.rcv_context = event->asoc->default_rcv_context;
+
+ put_cmsg(msghdr, IPPROTO_SCTP, SCTP_RCVINFO,
+ sizeof(rinfo), &rinfo);
+}
+
/* Do accounting for bytes received and hold a reference to the association
* for each skb.
*/