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/flow.h b/net/openvswitch/flow.h
index 9674e45..d08dcf7 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -99,8 +99,8 @@
 			} addr;
 			union {
 				struct {
-					__be16 src;		/* TCP/UDP source port. */
-					__be16 dst;		/* TCP/UDP destination port. */
+					__be16 src;		/* TCP/UDP/SCTP source port. */
+					__be16 dst;		/* TCP/UDP/SCTP destination port. */
 				} tp;
 				struct {
 					u8 sha[ETH_ALEN];	/* ARP source hardware address. */
@@ -115,8 +115,8 @@
 			} addr;
 			__be32 label;			/* IPv6 flow label. */
 			struct {
-				__be16 src;		/* TCP/UDP source port. */
-				__be16 dst;		/* TCP/UDP destination port. */
+				__be16 src;		/* TCP/UDP/SCTP source port. */
+				__be16 dst;		/* TCP/UDP/SCTP destination port. */
 			} tp;
 			struct {
 				struct in6_addr target;	/* ND target address. */