[SCTP]: Add receive buffer accounting.

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/input.c

@@ -100,6 +100,21 @@ static inline int sctp_rcv_checksum(struct sk_buff *skb)
 	return 0;
 }
 
+/* The free routine for skbuffs that sctp receives */
+static void sctp_rfree(struct sk_buff *skb)
+{
+	atomic_sub(sizeof(struct sctp_chunk),&skb->sk->sk_rmem_alloc);
+	sock_rfree(skb);
+}
+
+/* The ownership wrapper routine to do receive buffer accounting */
+static void sctp_rcv_set_owner_r(struct sk_buff *skb, struct sock *sk)
+{
+	skb_set_owner_r(skb,sk);
+	skb->destructor = sctp_rfree;
+	atomic_add(sizeof(struct sctp_chunk),&sk->sk_rmem_alloc);
+}
+
 /*
  * This is the routine which IP calls when receiving an SCTP packet.
  */
@@ -183,6 +198,11 @@ int sctp_rcv(struct sk_buff *skb)
 	rcvr = asoc ? &asoc->base : &ep->base;
 	sk = rcvr->sk;
 
+	if ((sk) && (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)) {
+		goto discard_release;
+	}
+
+
 	/* SCTP seems to always need a timestamp right now (FIXME) */
 	if (skb->stamp.tv_sec == 0) {
 		do_gettimeofday(&skb->stamp);
@@ -203,6 +223,8 @@ int sctp_rcv(struct sk_buff *skb)
 		goto discard_release;
 	}
 
+	sctp_rcv_set_owner_r(skb,sk);
+
 	/* Remember what endpoint is to handle this packet. */
 	chunk->rcvr = rcvr;