From 2347c80ff127b94ddaa675e2b78ab4cef46dc905 Mon Sep 17 00:00:00 2001 From: Geir Ola Vaagland Date: Sat, 12 Jul 2014 20:30:38 +0200 Subject: net: sctp: implement rfc6458, 5.3.6. SCTP_NXTINFO cmsg support This patch implements section 5.3.6. of RFC6458, that is, support for 'SCTP Next Receive Information Structure' (SCTP_NXTINFO) which is placed into ancillary data cmsghdr structure for each recvmsg() call, if this information is already available when delivering the current message. This option can be enabled/disabled via setsockopt(2) on SOL_SCTP level by setting an int value with 1/0 for SCTP_RECVNXTINFO in user space applications as per RFC6458, section 8.1.30. The sctp_nxtinfo structure is defined as per RFC as below ... struct sctp_nxtinfo { uint16_t nxt_sid; uint16_t nxt_flags; uint32_t nxt_ppid; uint32_t nxt_length; sctp_assoc_t nxt_assoc_id; }; ... and provided under cmsg_level IPPROTO_SCTP, cmsg_type SCTP_NXTINFO, while cmsg_data[] contains struct sctp_nxtinfo. Joint work with Daniel Borkmann. Signed-off-by: Geir Ola Vaagland Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/sctp/socket.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++---- net/sctp/ulpevent.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+), 4 deletions(-) (limited to 'net/sctp') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 9c19388..9bca87e 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -2060,8 +2060,6 @@ static int sctp_skb_pull(struct sk_buff *skb, int len) * flags - flags sent or received with the user message, see Section * 5 for complete description of the flags. */ -static struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *); - static int sctp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len, int noblock, int flags, int *addr_len) @@ -2112,6 +2110,9 @@ static int sctp_recvmsg(struct kiocb *iocb, struct sock *sk, sp->pf->skb_msgname(skb, msg->msg_name, addr_len); } + /* Check if we allow SCTP_NXTINFO. */ + if (sp->recvnxtinfo) + sctp_ulpevent_read_nxtinfo(event, msg, sk); /* Check if we allow SCTP_RCVINFO. */ if (sp->recvrcvinfo) sctp_ulpevent_read_rcvinfo(event, msg); @@ -3611,6 +3612,22 @@ static int sctp_setsockopt_recvrcvinfo(struct sock *sk, return 0; } +static int sctp_setsockopt_recvnxtinfo(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)->recvnxtinfo = (val == 0) ? 0 : 1; + + return 0; +} + /* API 6.2 setsockopt(), getsockopt() * * Applications use setsockopt() and getsockopt() to set or retrieve @@ -3765,6 +3782,9 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname, case SCTP_RECVRCVINFO: retval = sctp_setsockopt_recvrcvinfo(sk, optval, optlen); break; + case SCTP_RECVNXTINFO: + retval = sctp_setsockopt_recvnxtinfo(sk, optval, optlen); + break; default: retval = -ENOPROTOOPT; break; @@ -4012,6 +4032,7 @@ static int sctp_init_sock(struct sock *sk) sp->nodelay = 0; sp->recvrcvinfo = 0; + sp->recvnxtinfo = 0; /* Enable by default. */ sp->v4mapped = 1; @@ -5814,6 +5835,26 @@ static int sctp_getsockopt_recvrcvinfo(struct sock *sk, int len, return 0; } +static int sctp_getsockopt_recvnxtinfo(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)->recvnxtinfo) + 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) { @@ -5960,6 +6001,9 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname, case SCTP_RECVRCVINFO: retval = sctp_getsockopt_recvrcvinfo(sk, len, optval, optlen); break; + case SCTP_RECVNXTINFO: + retval = sctp_getsockopt_recvnxtinfo(sk, len, optval, optlen); + break; default: retval = -ENOPROTOOPT; break; @@ -6602,8 +6646,8 @@ out: * Note: This is pretty much the same routine as in core/datagram.c * with a few changes to make lksctp work. */ -static struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, - int noblock, int *err) +struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, + int noblock, int *err) { int error; struct sk_buff *skb; diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c index b31f365..e049298 100644 --- a/net/sctp/ulpevent.c +++ b/net/sctp/ulpevent.c @@ -911,6 +911,44 @@ void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event, sizeof(rinfo), &rinfo); } +/* RFC6458, Section 5.3.6. SCTP Next Receive Information Structure + * (SCTP_NXTINFO) + */ +static void __sctp_ulpevent_read_nxtinfo(const struct sctp_ulpevent *event, + struct msghdr *msghdr, + const struct sk_buff *skb) +{ + struct sctp_nxtinfo nxtinfo; + + memset(&nxtinfo, 0, sizeof(nxtinfo)); + nxtinfo.nxt_sid = event->stream; + nxtinfo.nxt_ppid = event->ppid; + nxtinfo.nxt_flags = event->flags; + if (sctp_ulpevent_is_notification(event)) + nxtinfo.nxt_flags |= SCTP_NOTIFICATION; + nxtinfo.nxt_length = skb->len; + nxtinfo.nxt_assoc_id = sctp_assoc2id(event->asoc); + + put_cmsg(msghdr, IPPROTO_SCTP, SCTP_NXTINFO, + sizeof(nxtinfo), &nxtinfo); +} + +void sctp_ulpevent_read_nxtinfo(const struct sctp_ulpevent *event, + struct msghdr *msghdr, + struct sock *sk) +{ + struct sk_buff *skb; + int err; + + skb = sctp_skb_recv_datagram(sk, MSG_PEEK, 1, &err); + if (skb != NULL) { + __sctp_ulpevent_read_nxtinfo(sctp_skb2event(skb), + msghdr, skb); + /* Just release refcount here. */ + kfree_skb(skb); + } +} + /* Do accounting for bytes received and hold a reference to the association * for each skb. */ -- cgit v1.1