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Diffstat (limited to 'net/ipv4/udp.c')
-rw-r--r--net/ipv4/udp.c40
1 files changed, 22 insertions, 18 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 44f6a20fa29d..f140048334ce 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 +1599,16 @@ 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 xchg() 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;
+ old = xchg(&sk->sk_rx_dst, dst);
+ dst_release(old);
}
/*
@@ -1739,15 +1739,16 @@ 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 +1914,20 @@ 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,