openvswitch: Fix checksum update for actions on UDP packets.

When modifying IP addresses or ports on a UDP packet we don't
correctly follow the rules for unchecksummed packets.  This meant
that packets without a checksum can be given a incorrect new checksum
and packets with a checksum can become marked as being unchecksummed.
This fixes it to handle those requirements.

Signed-off-by: Jesse Gross <jesse@nicira.com>

1 files changed, 32 insertions, 12 deletions

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 2725d1bdf291..48badffaafc1 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007-2011 Nicira Networks.
+ * Copyright (c) 2007-2012 Nicira Networks.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
@@ -145,9 +145,16 @@ static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
                         inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
                                                  *addr, new_addr, 1);
         } else if (nh->protocol == IPPROTO_UDP) {
-                if (likely(transport_len >= sizeof(struct udphdr)))
-                        inet_proto_csum_replace4(&udp_hdr(skb)->check, skb,
-                                                 *addr, new_addr, 1);
+                if (likely(transport_len >= sizeof(struct udphdr))) {
+                        struct udphdr *uh = udp_hdr(skb);
+
+                        if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
+                                inet_proto_csum_replace4(&uh->check, skb,
+                                                         *addr, new_addr, 1);
+                                if (!uh->check)
+                                        uh->check = CSUM_MANGLED_0;
+                        }
+                }
         }
 
         csum_replace4(&nh->check, *addr, new_addr);
@@ -197,8 +204,22 @@ static void set_tp_port(struct sk_buff *skb, __be16 *port,
         skb->rxhash = 0;
 }
 
-static int set_udp_port(struct sk_buff *skb,
-                        const struct ovs_key_udp *udp_port_key)
+static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
+{
+        struct udphdr *uh = udp_hdr(skb);
+
+        if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
+                set_tp_port(skb, port, new_port, &uh->check);
+
+                if (!uh->check)
+                        uh->check = CSUM_MANGLED_0;
+        } else {
+                *port = new_port;
+                skb->rxhash = 0;
+        }
+}
+
+static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
 {
         struct udphdr *uh;
         int err;
@@ -210,16 +231,15 @@ static int set_udp_port(struct sk_buff *skb,
 
         uh = udp_hdr(skb);
         if (udp_port_key->udp_src != uh->source)
-                set_tp_port(skb, &uh->source, udp_port_key->udp_src, &uh->check);
+                set_udp_port(skb, &uh->source, udp_port_key->udp_src);
 
         if (udp_port_key->udp_dst != uh->dest)
-                set_tp_port(skb, &uh->dest, udp_port_key->udp_dst, &uh->check);
+                set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
 
         return 0;
 }
 
-static int set_tcp_port(struct sk_buff *skb,
-                        const struct ovs_key_tcp *tcp_port_key)
+static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 {
         struct tcphdr *th;
         int err;
@@ -328,11 +348,11 @@ static int execute_set_action(struct sk_buff *skb,
                 break;
 
         case OVS_KEY_ATTR_TCP:
-                err = set_tcp_port(skb, nla_data(nested_attr));
+                err = set_tcp(skb, nla_data(nested_attr));
                 break;
 
         case OVS_KEY_ATTR_UDP:
-                err = set_udp_port(skb, nla_data(nested_attr));
+                err = set_udp(skb, nla_data(nested_attr));
                 break;
         }