From 64f0f5d18a47c703c85576375cc010e83dac6a48 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 25 Aug 2017 14:31:01 +0200 Subject: [PATCH] udp6: set rx_dst_cookie on rx_dst updates Currently, in the udp6 code, the dst cookie is not initialized/updated concurrently with the RX dst used by early demux. As a result, the dst_check() in the early_demux path always fails, the rx dst cache is always invalidated, and we can't really leverage significant gain from the demux lookup. Fix it adding udp6 specific variant of sk_rx_dst_set() and use it to set the dst cookie when the dst entry is really changed. The issue is there since the introduction of early demux for ipv6. Fixes: 5425077d73e0 ("net: ipv6: Add early demux handler for UDP unicast") Acked-by: Hannes Frederic Sowa Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- include/net/udp.h | 2 +- net/ipv4/udp.c | 4 +++- net/ipv6/udp.c | 11 ++++++++++- 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/include/net/udp.h b/include/net/udp.h index 586de4b811b5..626c2d8a70c5 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -260,7 +260,7 @@ static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, } void udp_v4_early_demux(struct sk_buff *skb); -void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); +bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); int udp_get_port(struct sock *sk, unsigned short snum, int (*saddr_cmp)(const struct sock *, const struct sock *)); diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index cd1d044a7fa5..a6dc48d76a29 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1929,14 +1929,16 @@ static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) /* For TCP sockets, sk_rx_dst is protected by socket lock * For UDP, we use xchg() to guard against concurrent changes. */ -void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) +bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) { struct dst_entry *old; if (dst_hold_safe(dst)) { old = xchg(&sk->sk_rx_dst, dst); dst_release(old); + return old != dst; } + return false; } EXPORT_SYMBOL(udp_sk_rx_dst_set); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 20039c8501eb..d6886228e1d0 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -768,6 +768,15 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, return 0; } +static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) +{ + if (udp_sk_rx_dst_set(sk, dst)) { + const struct rt6_info *rt = (const struct rt6_info *)dst; + + inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt); + } +} + int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, int proto) { @@ -817,7 +826,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, int ret; if (unlikely(sk->sk_rx_dst != dst)) - udp_sk_rx_dst_set(sk, dst); + udp6_sk_rx_dst_set(sk, dst); ret = udpv6_queue_rcv_skb(sk, skb); sock_put(sk);