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/socket.c b/net/sctp/socket.c
index d61729e..9c19388 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2112,9 +2112,13 @@
sp->pf->skb_msgname(skb, msg->msg_name, addr_len);
}
+ /* Check if we allow SCTP_RCVINFO. */
+ if (sp->recvrcvinfo)
+ sctp_ulpevent_read_rcvinfo(event, msg);
/* Check if we allow SCTP_SNDRCVINFO. */
if (sp->subscribe.sctp_data_io_event)
sctp_ulpevent_read_sndrcvinfo(event, msg);
+
#if 0
/* FIXME: we should be calling IP/IPv6 layers. */
if (sk->sk_protinfo.af_inet.cmsg_flags)
@@ -3541,7 +3545,6 @@
return 0;
}
-
/*
* SCTP_PEER_ADDR_THLDS
*
@@ -3592,6 +3595,22 @@
return 0;
}
+static int sctp_setsockopt_recvrcvinfo(struct sock *sk,
+ char __user *optval,
+ unsigned int optlen)
+{
+ int val;
+
+ if (optlen < sizeof(int))
+ return -EINVAL;
+ if (get_user(val, (int __user *) optval))
+ return -EFAULT;
+
+ sctp_sk(sk)->recvrcvinfo = (val == 0) ? 0 : 1;
+
+ return 0;
+}
+
/* API 6.2 setsockopt(), getsockopt()
*
* Applications use setsockopt() and getsockopt() to set or retrieve
@@ -3743,6 +3762,9 @@
case SCTP_PEER_ADDR_THLDS:
retval = sctp_setsockopt_paddr_thresholds(sk, optval, optlen);
break;
+ case SCTP_RECVRCVINFO:
+ retval = sctp_setsockopt_recvrcvinfo(sk, optval, optlen);
+ break;
default:
retval = -ENOPROTOOPT;
break;
@@ -3989,6 +4011,8 @@
/* Enable Nagle algorithm by default. */
sp->nodelay = 0;
+ sp->recvrcvinfo = 0;
+
/* Enable by default. */
sp->v4mapped = 1;
@@ -5770,6 +5794,26 @@
return 0;
}
+static int sctp_getsockopt_recvrcvinfo(struct sock *sk, int len,
+ char __user *optval,
+ int __user *optlen)
+{
+ int val = 0;
+
+ if (len < sizeof(int))
+ return -EINVAL;
+
+ len = sizeof(int);
+ if (sctp_sk(sk)->recvrcvinfo)
+ val = 1;
+ if (put_user(len, optlen))
+ return -EFAULT;
+ if (copy_to_user(optval, &val, len))
+ return -EFAULT;
+
+ return 0;
+}
+
static int sctp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
@@ -5913,6 +5957,9 @@
case SCTP_GET_ASSOC_STATS:
retval = sctp_getsockopt_assoc_stats(sk, len, optval, optlen);
break;
+ case SCTP_RECVRCVINFO:
+ retval = sctp_getsockopt_recvrcvinfo(sk, len, optval, optlen);
+ break;
default:
retval = -ENOPROTOOPT;
break;
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.
*/