From 0b95227a7ba7e69f795757cd7c839eff0615f2d1 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Wed, 26 Feb 2014 01:20:43 +0100 Subject: [PATCH] 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 Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- 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(-) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 017badb1aec7..00e3f12cb2f9 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -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) diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h index e9a1d2d973b6..0d8e0f0342dc 100644 --- a/include/uapi/linux/in6.h +++ b/include/uapi/linux/in6.h @@ -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 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; -- 2.30.2