gre: Don't require incoming checksum.

The current meaning of the GRE checksum option is to include
checksums on transmit and require packets to have them on receive.
In addition, incoming packets with checksums are always validated
regardless of this option.  Requiring checksums on receive creates
surprising behavior and interoperability issues.  This disables the
requirement on receive.  The new behavior is that the sender decides
whether to checksum packets and the receiver will validate packets
with checksums (similar to UDP).

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

diff --git a/datapath/vport-gre.c b/datapath/vport-gre.c
index 2bddc871093205c6442a24e4954c5bd538b47693..b471b08aea6771b0e61a12e10dc1e1926dc92027 100644 (file)
--- a/datapath/vport-gre.c
+++ b/datapath/vport-gre.c
@@ -592,7 +592,7 @@ static void create_gre_header(struct sk_buff *skb,
                options--;
        }
 
-       if (mutable->port_config.flags & GRE_F_OUT_CSUM) {
+       if (mutable->port_config.flags & GRE_F_CSUM) {
                greh->flags |= GRE_CSUM;
 
                *options = 0;
@@ -787,7 +787,7 @@ static void gre_err(struct sk_buff *skb, u32 info)
            !!(mutable->port_config.flags & GRE_F_OUT_KEY_ACTION))
                return;
 
-       if ((mutable->port_config.flags & GRE_F_OUT_CSUM) && !(flags & GRE_CSUM))
+       if ((mutable->port_config.flags & GRE_F_CSUM) && !(flags & GRE_CSUM))
                return;
 
        tunnel_hdr_len += iph->ihl << 2;
@@ -881,11 +881,6 @@ static int gre_rcv(struct sk_buff *skb)
                goto error;
        }
 
-       if ((mutable->port_config.flags & GRE_F_IN_CSUM) && !(flags & GRE_CSUM)) {
-               vport_record_error(vport, VPORT_E_RX_CRC);
-               goto error;
-       }
-
        if (!pskb_pull(skb, hdr_len) || !pskb_may_pull(skb, ETH_HLEN)) {
                vport_record_error(vport, VPORT_E_RX_ERROR);
                goto error;
@@ -1196,7 +1191,7 @@ static int set_config(const struct vport *cur_vport,
 
        mutable->tunnel_hlen = sizeof(struct iphdr) + GRE_HEADER_SECTION;
 
-       if (mutable->port_config.flags & GRE_F_OUT_CSUM)
+       if (mutable->port_config.flags & GRE_F_CSUM)
                mutable->tunnel_hlen += GRE_HEADER_SECTION;
 
        if (mutable->port_config.out_key ||

diff --git a/include/openvswitch/gre.h b/include/openvswitch/gre.h
index 396a67d9d75167a250d4b94f61b1213325909c5a..a9ac1d9843571b0e4c5f685186815e16821c5a14 100644 (file)
--- a/include/openvswitch/gre.h
+++ b/include/openvswitch/gre.h
@@ -42,8 +42,7 @@
 
 #include <linux/types.h>
 
-#define GRE_F_IN_CSUM          (1 << 0) /* Require incoming packets to have checksums. */
-#define GRE_F_OUT_CSUM         (1 << 1) /* Checksum outgoing packets. */
+#define GRE_F_CSUM             (1 << 1) /* Checksum packets. */
 #define GRE_F_IN_KEY_MATCH     (1 << 2) /* Store the key in tun_id to match in flow table. */
 #define GRE_F_OUT_KEY_ACTION   (1 << 3) /* Get the key from a SET_TUNNEL action. */
 #define GRE_F_TOS_INHERIT      (1 << 4) /* Inherit the ToS from the inner packet. */

diff --git a/lib/netdev-gre.c b/lib/netdev-gre.c
index 69411dbd7bf97e1e8148b12dd5a5af7113096a1d..04a83327750ff05f498b1a6c94f6eedbe8cf6fa7 100644 (file)
--- a/lib/netdev-gre.c
+++ b/lib/netdev-gre.c
@@ -111,8 +111,7 @@ parse_config(const char *name, const struct shash *args,
             }
         } else if (!strcmp(node->name, "csum")) {
             if (!strcmp(node->data, "true")) {
-                config->flags |= GRE_F_IN_CSUM;
-                config->flags |= GRE_F_OUT_CSUM;
+                config->flags |= GRE_F_CSUM;
             }
         } else if (!strcmp(node->name, "pmtud")) {
             if (!strcmp(node->data, "false")) {

diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index f3864047410923531947128fb0e726941a5bf6a3..ce1c7140740631e90b996ce028b03ac729b04f0c 100644 (file)
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -505,8 +505,9 @@
             </dl>
             <dl>
               <dt><code>csum</code></dt>
-              <dd>Optional.  Compute GRE checksums for outgoing packets and
-                require checksums for incoming packets.  Note that GRE checksums
+              <dd>Optional.  Compute GRE checksums on outgoing packets.
+                Checksums present on incoming packets will be validated
+                regardless of this setting.  Note that GRE checksums
                 impose a significant performance penalty as they cover the
                 entire packet.  As the contents of the packet is typically
                 covered by L3 and L4 checksums, this additional checksum only