dpif-netdev: Fix UDP checksum calculation.

dpif-netdev incorrectly calculated the UDP checksum when modifying
source and destination ports.

Signed-off-by: Ethan Jackson <ethan@nicira.com>

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 2c416e357dcbe7b4b2ea4adad4c1659f724ed27c..742d00c69cc4c220953afb242947d18ed4fbaf52 100644 (file)
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -1137,11 +1137,21 @@ dp_netdev_set_udp_port(struct ofpbuf *packet, const struct ovs_key_udp *udp_key)
 {
     struct udp_header *uh = packet->l4;
 
-    if (uh->udp_src != udp_key->udp_src) {
-        dp_netdev_set_port(&uh->udp_src, udp_key->udp_src, &uh->udp_csum);
-    }
-    if (uh->udp_dst != udp_key->udp_dst) {
-        dp_netdev_set_port(&uh->udp_dst, udp_key->udp_dst, &uh->udp_csum);
+    if (uh->udp_csum) {
+        if (uh->udp_src != udp_key->udp_src) {
+            dp_netdev_set_port(&uh->udp_src, udp_key->udp_src, &uh->udp_csum);
+        }
+
+        if (uh->udp_dst != udp_key->udp_dst) {
+            dp_netdev_set_port(&uh->udp_dst, udp_key->udp_dst, &uh->udp_csum);
+        }
+
+        if (!uh->udp_csum) {
+            uh->udp_csum = htons(0xffff);
+        }
+    } else {
+        uh->udp_src = udp_key->udp_src;
+        uh->udp_dst = udp_key->udp_dst;
     }
 }