@@ -171,7 +171,14 @@ static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
static inline bool ip6_sk_accept_pmtu(const struct sock *sk)
{
- return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE;
+ return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE &&
+ inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_OMIT;
+}
+
+static inline bool ip6_sk_local_df(const struct sock *sk)
+{
+ return inet6_sk(sk)->pmtudisc < IPV6_PMTUDISC_DO ||
+ inet6_sk(sk)->pmtudisc == IPV6_PMTUDISC_OMIT;
}
static inline struct in6_addr *rt6_nexthop(struct rt6_info *rt)
@@ -185,6 +185,10 @@ struct in6_flowlabel_req {
* also see comments on IP_PMTUDISC_INTERFACE
*/
#define IPV6_PMTUDISC_INTERFACE 4
+/* weaker version of IPV6_PMTUDISC_INTERFACE, which allows packets to
+ * get fragmented if they exceed the interface mtu
+ */
+#define IPV6_PMTUDISC_OMIT 5
/* Flowlabel */
#define IPV6_FLOWLABEL_MGR 32
@@ -1231,8 +1231,10 @@ 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 &&
@@ -1540,8 +1542,7 @@ 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));
@@ -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;
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> --- include/net/ip6_route.h | 9 ++++++++- include/uapi/linux/in6.h | 4 ++++ net/ipv6/ip6_output.c | 9 +++++---- net/ipv6/ipv6_sockglue.c | 2 +- 4 files changed, 18 insertions(+), 6 deletions(-)