From d8d9ef29886733428470655f2f99bc7493589fcb Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 16 Feb 2026 14:28:31 +0000 Subject: ipv4: icmp: icmpv4_xrlim_allow() optimization if net.ipv4.icmp_ratelimit is zero If net.ipv4.icmp_ratelimit is zero, we do not have to call inet_getpeer_v4() and inet_peer_xrlim_allow(). Both can be very expensive under DDOS. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260216142832.3834174-5-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv4/icmp.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index eff8487c0aba..a62b4c4033cc 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -316,23 +316,29 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, struct dst_entry *dst = &rt->dst; struct inet_peer *peer; struct net_device *dev; + int peer_timeout; bool rc = true; if (!apply_ratelimit) return true; + peer_timeout = READ_ONCE(net->ipv4.sysctl_icmp_ratelimit); + if (!peer_timeout) + goto out; + /* No rate limit on loopback */ rcu_read_lock(); dev = dst_dev_rcu(dst); if (dev && (dev->flags & IFF_LOOPBACK)) - goto out; + goto out_unlock; peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, l3mdev_master_ifindex_rcu(dev)); - rc = inet_peer_xrlim_allow(peer, - READ_ONCE(net->ipv4.sysctl_icmp_ratelimit)); -out: + rc = inet_peer_xrlim_allow(peer, peer_timeout); + +out_unlock: rcu_read_unlock(); +out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); else -- cgit v1.2.3