From 93b36cf3425b9bd9c56df7680fb237686b9c82ae Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Sun, 15 Dec 2013 03:41:14 +0100 Subject: [PATCH] ipv6: support IPV6_PMTU_INTERFACE on sockets IPV6_PMTU_INTERFACE is the same as IPV6_PMTU_PROBE for ipv6. Add it nontheless for symmetry with IPv4 sockets. Also drop incoming MTU information if this mode is enabled. The additional bit in ipv6_pinfo just eats in the padding behind the bitfield. There are no changes to the layout of the struct at all. Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- include/linux/ipv6.h | 2 +- include/net/ip6_route.h | 7 ++++++- include/uapi/linux/in6.h | 4 ++++ net/dccp/ipv6.c | 3 +++ net/ipv6/ip6_output.c | 6 +++--- net/ipv6/ipv6_sockglue.c | 2 +- net/ipv6/tcp_ipv6.c | 3 +++ net/ipv6/udp.c | 5 ++++- net/sctp/input.c | 3 +++ 9 files changed, 28 insertions(+), 7 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 3fde06645553..7e1ded0d8e45 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -191,7 +191,7 @@ struct ipv6_pinfo { /* sockopt flags */ __u16 recverr:1, sndflow:1, - pmtudisc:2, + pmtudisc:3, ipv6only:1, srcprefs:3, /* 001: prefer temporary address * 010: prefer public address diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 733747ce163c..c2626ce1f2ad 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -178,10 +178,15 @@ static inline int ip6_skb_dst_mtu(struct sk_buff *skb) { struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; - return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ? + return (np && np->pmtudisc >= IPV6_PMTUDISC_PROBE) ? skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb)); } +static inline bool ip6_sk_accept_pmtu(const struct sock *sk) +{ + return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE; +} + static inline struct in6_addr *rt6_nexthop(struct rt6_info *rt) { return &rt->rt6i_gateway; diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h index 440d5c479145..f94f1d013bf2 100644 --- a/include/uapi/linux/in6.h +++ b/include/uapi/linux/in6.h @@ -188,6 +188,10 @@ enum { #define IPV6_PMTUDISC_WANT 1 #define IPV6_PMTUDISC_DO 2 #define IPV6_PMTUDISC_PROBE 3 +/* same as IPV6_PMTUDISC_PROBE, provided for symetry with IPv4 + * also see comments on IP_PMTUDISC_INTERFACE + */ +#define IPV6_PMTUDISC_INTERFACE 4 /* Flowlabel */ #define IPV6_FLOWLABEL_MGR 32 diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 2b90a786e475..629019e6f8e9 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -141,6 +141,9 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, if (type == ICMPV6_PKT_TOOBIG) { struct dst_entry *dst = NULL; + if (!ip6_sk_accept_pmtu(sk)) + goto out; + if (sock_owned_by_user(sk)) goto out; if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 9a311cc79672..bc4e1bcdf4c0 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1165,10 +1165,10 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, np->cork.hop_limit = hlimit; np->cork.tclass = tclass; if (rt->dst.flags & DST_XFRM_TUNNEL) - mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ? + mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? rt->dst.dev->mtu : dst_mtu(&rt->dst); else - mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ? + mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? rt->dst.dev->mtu : dst_mtu(rt->dst.path); if (np->frag_size < mtu) { if (np->frag_size) @@ -1270,7 +1270,7 @@ alloc_new_skb: if (skb == NULL || skb_prev == NULL) ip6_append_data_mtu(&mtu, &maxfraglen, fragheaderlen, skb, rt, - np->pmtudisc == + np->pmtudisc >= IPV6_PMTUDISC_PROBE); skb_prev = skb; diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 759fbf96515b..af0ecb94b3b4 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 < IP_PMTUDISC_DONT || val > IP_PMTUDISC_PROBE) + if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_INTERFACE) goto e_inval; np->pmtudisc = val; retv = 0; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index da046a5d7ffb..d955487f2c54 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -397,6 +397,9 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, if (sk->sk_state == TCP_LISTEN) goto out; + if (!ip6_sk_accept_pmtu(sk)) + goto out; + tp->mtu_info = ntohl(info); if (!sock_owned_by_user(sk)) tcp_v6_mtu_reduced(sk); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 089c741a3992..65ed5cd79264 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -538,8 +538,11 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt, if (sk == NULL) return; - if (type == ICMPV6_PKT_TOOBIG) + if (type == ICMPV6_PKT_TOOBIG) { + if (!ip6_sk_accept_pmtu(sk)) + goto out; ip6_sk_update_pmtu(skb, sk, info); + } if (type == NDISC_REDIRECT) { ip6_sk_redirect(skb, sk); goto out; diff --git a/net/sctp/input.c b/net/sctp/input.c index 2a192a7c5d81..042ec6c9ae24 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -389,6 +389,9 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, if (!t || (t->pathmtu <= pmtu)) return; + if (!ip6_sk_accept_pmtu(sk)) + return; + if (sock_owned_by_user(sk)) { asoc->pmtu_pending = 1; t->pmtu_pending = 1; -- 2.30.2