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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: 93b36cf342 ("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>
hifive-unleashed-5.1
Hannes Frederic Sowa 2014-02-26 01:20:43 +01:00 committed by David S. Miller
parent 1b34657635
commit 0b95227a7b
4 changed files with 18 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/net/ip6_route.h
View File

@ -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)

4
include/uapi/linux/in6.h
View File

@ -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

9
net/ipv6/ip6_output.c
View File

@ -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));

2
net/ipv6/ipv6_sockglue.c
View File

@ -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;