openvswitch: Add SCTP support

This patch adds support for rewriting SCTP src,dst ports similar to the
functionality already available for TCP/UDP.

Rewriting SCTP ports is expensive due to double-recalculation of the
SCTP checksums; this is performed to ensure that packets traversing OVS
with invalid checksums will continue to the destination with any
checksum corruption intact.

Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index d29cd9a..2aa13bd 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -712,6 +712,12 @@
 
 		return validate_tp_port(flow_key);
 
+	case OVS_KEY_ATTR_SCTP:
+		if (flow_key->ip.proto != IPPROTO_SCTP)
+			return -EINVAL;
+
+		return validate_tp_port(flow_key);
+
 	default:
 		return -EINVAL;
 	}