ipv6: yet another new IPV6_MTU_DISCOVER option IPV6_PMTUDISC_OMIT

This option has the same semantic as IP_PMTUDISC_OMIT for IPv4 which
got recently introduced. It doesn't honor the path mtu discovered by the
host but in contrary to IPV6_PMTUDISC_INTERFACE allows the generation of
fragments if the packet size exceeds the MTU of the outgoing interface
MTU.

Fixes: 93b36cf3425b9b ("ipv6: support IPV6_PMTU_INTERFACE on sockets")
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 6 insertions, 5 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 070a2fae2375..be1b7f5a3a54 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1234,8 +1234,10 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
                               sizeof(struct frag_hdr) : 0) +
                              rt->rt6i_nfheader_len;
 
-                maxnonfragsize = (np->pmtudisc >= IPV6_PMTUDISC_DO) ?
-                                 mtu : sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
+                if (ip6_sk_local_df(sk))
+                        maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
+                else
+                        maxnonfragsize = mtu;
 
                 /* dontfrag active */
                 if ((cork->length + length > mtu - headersize) && dontfrag &&
@@ -1543,8 +1545,7 @@ int ip6_push_pending_frames(struct sock *sk)
         }
 
         /* Allow local fragmentation. */
-        if (np->pmtudisc < IPV6_PMTUDISC_DO)
-                skb->local_df = 1;
+        skb->local_df = ip6_sk_local_df(sk);
 
         *final_dst = fl6->daddr;
         __skb_pull(skb, skb_network_header_len(skb));
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 0a00f449de5e..edb58aff4ae7 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -722,7 +722,7 @@ done:
         case IPV6_MTU_DISCOVER:
                 if (optlen < sizeof(int))
                         goto e_inval;
-                if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_INTERFACE)
+                if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_OMIT)
                         goto e_inval;
                 np->pmtudisc = val;
                 retv = 0;