From ceb3320610d6f15ff20dd4c042b36473d77de76f Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 17 Jul 2012 11:31:28 -0700 Subject: [PATCH] ipv4: Kill routes during PMTU/redirect updates. Mark them obsolete so there will be a re-lookup to fetch the FIB nexthop exception info. Signed-off-by: David S. Miller --- include/net/dst.h | 1 + net/ipv4/route.c | 41 +++++++++++++++++++++++++++++------------ 2 files changed, 30 insertions(+), 12 deletions(-) diff --git a/include/net/dst.h b/include/net/dst.h index 0df661a0c2958f..baf59789006427 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -78,6 +78,7 @@ struct dst_entry { #define DST_OBSOLETE_NONE 0 #define DST_OBSOLETE_DEAD 2 #define DST_OBSOLETE_FORCE_CHK -1 +#define DST_OBSOLETE_KILL -2 unsigned short header_len; /* more space at head required */ unsigned short trailer_len; /* space to reserve at tail */ #ifdef CONFIG_IP_ROUTE_CLASSID diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 50d2498c928428..d52f7699c2fa80 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -673,7 +673,8 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, return; } -static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4) +static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, + bool kill_route) { __be32 new_gw = icmp_hdr(skb)->un.gateway; __be32 old_gw = ip_hdr(skb)->saddr; @@ -728,8 +729,8 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow update_or_create_fnhe(nh, fl4->daddr, new_gw, 0, 0); } - rt->rt_gateway = new_gw; - rt->rt_flags |= RTCF_REDIRECTED; + if (kill_route) + rt->dst.obsolete = DST_OBSOLETE_KILL; call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); } neigh_release(n); @@ -760,7 +761,7 @@ static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buf rt = (struct rtable *) dst; ip_rt_build_flow_key(&fl4, sk, skb); - __ip_do_redirect(rt, skb, &fl4); + __ip_do_redirect(rt, skb, &fl4, true); } static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) @@ -919,7 +920,7 @@ out: kfree_skb(skb); return 0; } -static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) +static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) { struct fib_result res; @@ -932,8 +933,7 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) update_or_create_fnhe(nh, fl4->daddr, 0, mtu, jiffies + ip_rt_mtu_expires); } - rt->rt_pmtu = mtu; - dst_set_expires(&rt->dst, ip_rt_mtu_expires); + return mtu; } static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, @@ -943,7 +943,14 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, struct flowi4 fl4; ip_rt_build_flow_key(&fl4, sk, skb); - __ip_rt_update_pmtu(rt, &fl4, mtu); + mtu = __ip_rt_update_pmtu(rt, &fl4, mtu); + + if (!rt->rt_pmtu) { + dst->obsolete = DST_OBSOLETE_KILL; + } else { + rt->rt_pmtu = mtu; + dst_set_expires(&rt->dst, ip_rt_mtu_expires); + } } void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, @@ -989,7 +996,7 @@ void ipv4_redirect(struct sk_buff *skb, struct net *net, RT_TOS(iph->tos), protocol, mark, flow_flags); rt = __ip_route_output_key(net, &fl4); if (!IS_ERR(rt)) { - __ip_do_redirect(rt, skb, &fl4); + __ip_do_redirect(rt, skb, &fl4, false); ip_rt_put(rt); } } @@ -1004,7 +1011,7 @@ void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); rt = __ip_route_output_key(sock_net(sk), &fl4); if (!IS_ERR(rt)) { - __ip_do_redirect(rt, skb, &fl4); + __ip_do_redirect(rt, skb, &fl4, false); ip_rt_put(rt); } } @@ -1014,7 +1021,15 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) { struct rtable *rt = (struct rtable *) dst; - if (rt_is_expired(rt)) + /* All IPV4 dsts are created with ->obsolete set to the value + * DST_OBSOLETE_FORCE_CHK which forces validation calls down + * into this function always. + * + * When a PMTU/redirect information update invalidates a + * route, this is indicated by setting obsolete to + * DST_OBSOLETE_KILL. + */ + if (dst->obsolete == DST_OBSOLETE_KILL || rt_is_expired(rt)) return NULL; return dst; } @@ -1186,8 +1201,10 @@ static void rt_bind_exception(struct rtable *rt, struct fib_nh *nh, __be32 daddr dst_set_expires(&rt->dst, diff); } } - if (gw) + if (gw) { + rt->rt_flags |= RTCF_REDIRECTED; rt->rt_gateway = gw; + } fnhe->fnhe_stamp = jiffies; break; }