From e81da0e113a1b7fc7449ae6213f65f89ccac6d06 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Mon, 8 Oct 2012 11:41:15 +0000 Subject: [PATCH] ipv4: fix sending of redirects After "Cache input routes in fib_info nexthops" (commit d2d68ba9fe) and "Elide fib_validate_source() completely when possible" (commit 7a9bc9b81a) we can not send ICMP redirects. It seems we should not cache the RTCF_DOREDIRECT flag in nh_rth_input because the same fib_info can be used for traffic that is not redirected, eg. from other input devices or from sources that are not in same subnet. As result, we have to disable the caching of RTCF_DOREDIRECT flag and to force source validation for the case when forwarding traffic to the input device. If traffic comes from directly connected source we allow redirection as it was done before both changes. Avoid setting RTCF_DOREDIRECT if IN_DEV_TX_REDIRECTS is disabled, this can avoid source address validation and to help caching the routes. After the change "Adjust semantics of rt->rt_gateway" (commit f8126f1d51) we should make sure our ICMP_REDIR_HOST messages contain daddr instead of 0.0.0.0 when target is directly connected. Signed-off-by: Julian Anastasov Signed-off-by: David S. Miller --- net/ipv4/fib_frontend.c | 3 ++- net/ipv4/route.c | 30 ++++++++++++++++-------------- 2 files changed, 18 insertions(+), 15 deletions(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 68c93d1bb03a..825c608826de 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -322,7 +322,8 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, { int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev); - if (!r && !fib_num_tclassid_users(dev_net(dev))) { + if (!r && !fib_num_tclassid_users(dev_net(dev)) && + (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) { *itag = 0; return 0; } diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 132e0dfee53a..b90da1bc2704 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -802,7 +802,8 @@ void ip_rt_send_redirect(struct sk_buff *skb) net = dev_net(rt->dst.dev); peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1); if (!peer) { - icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); + icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, + rt_nexthop(rt, ip_hdr(skb)->daddr)); return; } @@ -827,7 +828,9 @@ void ip_rt_send_redirect(struct sk_buff *skb) time_after(jiffies, (peer->rate_last + (ip_rt_redirect_load << peer->rate_tokens)))) { - icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); + __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); + + icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); peer->rate_last = jiffies; ++peer->rate_tokens; #ifdef CONFIG_IP_ROUTE_VERBOSE @@ -835,7 +838,7 @@ void ip_rt_send_redirect(struct sk_buff *skb) peer->rate_tokens == ip_rt_redirect_number) net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", &ip_hdr(skb)->saddr, inet_iif(skb), - &ip_hdr(skb)->daddr, &rt->rt_gateway); + &ip_hdr(skb)->daddr, &gw); #endif } out_put_peer: @@ -1442,10 +1445,13 @@ static int __mkroute_input(struct sk_buff *skb, goto cleanup; } - if (out_dev == in_dev && err && + do_cache = res->fi && !itag; + if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && (IN_DEV_SHARED_MEDIA(out_dev) || - inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) + inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) { flags |= RTCF_DOREDIRECT; + do_cache = false; + } if (skb->protocol != htons(ETH_P_IP)) { /* Not IP (i.e. ARP). Do not create route, if it is @@ -1462,15 +1468,11 @@ static int __mkroute_input(struct sk_buff *skb, } } - do_cache = false; - if (res->fi) { - if (!itag) { - rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); - if (rt_cache_valid(rth)) { - skb_dst_set_noref(skb, &rth->dst); - goto out; - } - do_cache = true; + if (do_cache) { + rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); + if (rt_cache_valid(rth)) { + skb_dst_set_noref(skb, &rth->dst); + goto out; } } -- 2.39.5