From a175a723301a8a4a9fedf9ce5b8ca586e7a97b40 Mon Sep 17 00:00:00 2001
From: Joe Stringer <joe@wand.net.nz>
Date: Thu, 22 Aug 2013 12:30:48 -0700
Subject: 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>
---
 net/openvswitch/actions.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

(limited to 'net/openvswitch/actions.c')

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 1f680222f4f7..65cfaa816075 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -22,6 +22,7 @@
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/openvswitch.h>
+#include <linux/sctp.h>
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <linux/in6.h>
@@ -31,6 +32,7 @@
 #include <net/ipv6.h>
 #include <net/checksum.h>
 #include <net/dsfield.h>
+#include <net/sctp/checksum.h>
 
 #include "datapath.h"
 #include "vport.h"
@@ -352,6 +354,39 @@ static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 	return 0;
 }
 
+static int set_sctp(struct sk_buff *skb,
+		     const struct ovs_key_sctp *sctp_port_key)
+{
+	struct sctphdr *sh;
+	int err;
+	unsigned int sctphoff = skb_transport_offset(skb);
+
+	err = make_writable(skb, sctphoff + sizeof(struct sctphdr));
+	if (unlikely(err))
+		return err;
+
+	sh = sctp_hdr(skb);
+	if (sctp_port_key->sctp_src != sh->source ||
+	    sctp_port_key->sctp_dst != sh->dest) {
+		__le32 old_correct_csum, new_csum, old_csum;
+
+		old_csum = sh->checksum;
+		old_correct_csum = sctp_compute_cksum(skb, sctphoff);
+
+		sh->source = sctp_port_key->sctp_src;
+		sh->dest = sctp_port_key->sctp_dst;
+
+		new_csum = sctp_compute_cksum(skb, sctphoff);
+
+		/* Carry any checksum errors through. */
+		sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
+
+		skb->rxhash = 0;
+	}
+
+	return 0;
+}
+
 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 {
 	struct vport *vport;
@@ -461,6 +496,10 @@ static int execute_set_action(struct sk_buff *skb,
 	case OVS_KEY_ATTR_UDP:
 		err = set_udp(skb, nla_data(nested_attr));
 		break;
+
+	case OVS_KEY_ATTR_SCTP:
+		err = set_sctp(skb, nla_data(nested_attr));
+		break;
 	}
 
 	return err;
-- 
cgit v1.2.3