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>

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 2725d1bdf2916b1b0545dbb9d400d931d7abd974..48badffaafc1a2c0ce0b8d8ec7a0729c2d2cbb42 100644 (file)
--- 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;
        }