netfilter: ipvs: do not create conn for ABORT packet in sctp_conn_schedule

There's no reason for ipvs to create a conn for an ABORT packet
even if sysctl_sloppy_sctp is set.

This patch is to accept it without creating a conn, just as ipvs
does for tcp's RST packet.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/ipvs/ip_vs_proto_sctp.c

@@ -25,7 +25,8 @@ sctp_conn_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
 			sch = skb_header_pointer(skb, iph->len + sizeof(_sctph),
 						 sizeof(_schunkh), &_schunkh);
 			if (sch) {
-				if (!(sysctl_sloppy_sctp(ipvs) ||
+				if (sch->type == SCTP_CID_ABORT ||
+				    !(sysctl_sloppy_sctp(ipvs) ||
 				      sch->type == SCTP_CID_INIT))
 					return 1;
 				ports = &sh->source;