diff options
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 47 |
1 files changed, 28 insertions, 19 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 44f6a20fa29..62c19fdd102 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -560,15 +560,11 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport, struct udp_table *udptable) { - struct sock *sk; const struct iphdr *iph = ip_hdr(skb); - if (unlikely(sk = skb_steal_sock(skb))) - return sk; - else - return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport, - iph->daddr, dport, inet_iif(skb), - udptable); + return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport, + iph->daddr, dport, inet_iif(skb), + udptable); } struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, @@ -1603,12 +1599,21 @@ static void flush_stack(struct sock **stack, unsigned int count, kfree_skb(skb1); } -static void udp_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) +/* For TCP sockets, sk_rx_dst is protected by socket lock + * For UDP, we use sk_dst_lock to guard against concurrent changes. + */ +static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) { - struct dst_entry *dst = skb_dst(skb); + struct dst_entry *old; - dst_hold(dst); - sk->sk_rx_dst = dst; + spin_lock(&sk->sk_dst_lock); + old = sk->sk_rx_dst; + if (likely(old != dst)) { + dst_hold(dst); + sk->sk_rx_dst = dst; + dst_release(old); + } + spin_unlock(&sk->sk_dst_lock); } /* @@ -1739,15 +1744,16 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, if (udp4_csum_init(skb, uh, proto)) goto csum_error; - if (skb->sk) { + sk = skb_steal_sock(skb); + if (sk) { + struct dst_entry *dst = skb_dst(skb); int ret; - sk = skb->sk; - if (unlikely(sk->sk_rx_dst == NULL)) - udp_sk_rx_dst_set(sk, skb); + if (unlikely(sk->sk_rx_dst != dst)) + udp_sk_rx_dst_set(sk, dst); ret = udp_queue_rcv_skb(sk, skb); - + sock_put(sk); /* a return value > 0 means to resubmit the input, but * it wants the return to be -protocol, or 0 */ @@ -1913,17 +1919,20 @@ static struct sock *__udp4_lib_demux_lookup(struct net *net, void udp_v4_early_demux(struct sk_buff *skb) { - const struct iphdr *iph = ip_hdr(skb); - const struct udphdr *uh = udp_hdr(skb); + struct net *net = dev_net(skb->dev); + const struct iphdr *iph; + const struct udphdr *uh; struct sock *sk; struct dst_entry *dst; - struct net *net = dev_net(skb->dev); int dif = skb->dev->ifindex; /* validate the packet */ if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr))) return; + iph = ip_hdr(skb); + uh = udp_hdr(skb); + if (skb->pkt_type == PACKET_BROADCAST || skb->pkt_type == PACKET_MULTICAST) sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr, |