tunneling: Add df_default and df_inherit tunnel options.

[sliver-openvswitch.git] / datapath / tunnel.c

diff --git a/datapath/tunnel.c b/datapath/tunnel.c
index 899d1cd..70a4cd7 100644 (file)
--- a/datapath/tunnel.c
+++ b/datapath/tunnel.c
@@ -725,8 +725,9 @@ static bool check_mtu(struct sk_buff *skb,
                      const struct tnl_mutable_config *mutable,
                      const struct rtable *rt, __be16 *frag_offp)
 {
+       bool df_inherit = mutable->flags & TNL_F_DF_INHERIT;
        bool pmtud = mutable->flags & TNL_F_PMTUD;
-       __be16 frag_off = 0;
+       __be16 frag_off = mutable->flags & TNL_F_DF_DEFAULT ? htons(IP_DF) : 0;
        int mtu = 0;
        unsigned int packet_length = skb->len - ETH_HLEN;
 
@@ -738,8 +739,6 @@ static bool check_mtu(struct sk_buff *skb,
        if (pmtud) {
                int vlan_header = 0;
 
-               frag_off = htons(IP_DF);
-
                /* The tag needs to go in packet regardless of where it
                 * currently is, so subtract it from the MTU.
                 */
@@ -756,7 +755,8 @@ static bool check_mtu(struct sk_buff *skb,
        if (skb->protocol == htons(ETH_P_IP)) {
                struct iphdr *iph = ip_hdr(skb);
 
-               frag_off |= iph->frag_off & htons(IP_DF);
+               if (df_inherit)
+                       frag_off = iph->frag_off & htons(IP_DF);
 
                if (pmtud && iph->frag_off & htons(IP_DF)) {
                        mtu = max(mtu, IP_MIN_MTU);
@@ -769,8 +769,10 @@ static bool check_mtu(struct sk_buff *skb,
        }
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
        else if (skb->protocol == htons(ETH_P_IPV6)) {
-               /* IPv6 requires PMTUD if the packet is above the minimum MTU. */
-               if (packet_length > IPV6_MIN_MTU)
+               /* IPv6 requires end hosts to do fragmentation
+                * if the packet is above the minimum MTU.
+                */
+               if (df_inherit && packet_length > IPV6_MIN_MTU)
                        frag_off = htons(IP_DF);
 
                if (pmtud) {