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authorEric Dumazet <eric.dumazet@gmail.com>2010-09-08 05:08:44 +0000
committerDavid S. Miller <davem@davemloft.net>2010-09-08 21:45:01 -0700
commit719f835853a92f6090258114a72ffe41f09155cd (patch)
treea077b05397bf07a096be7f07b50375c5ed918ac2 /net
parentae2688d59b5f861dc70a091d003773975d2ae7fb (diff)
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udp: add rehash on connect()
commit 30fff923 introduced in linux-2.6.33 (udp: bind() optimisation) added a secondary hash on UDP, hashed on (local addr, local port). Problem is that following sequence : fd = socket(...) connect(fd, &remote, ...) not only selects remote end point (address and port), but also sets local address, while UDP stack stored in secondary hash table the socket while its local address was INADDR_ANY (or ipv6 equivalent) Sequence is : - autobind() : choose a random local port, insert socket in hash tables [while local address is INADDR_ANY] - connect() : set remote address and port, change local address to IP given by a route lookup. When an incoming UDP frame comes, if more than 10 sockets are found in primary hash table, we switch to secondary table, and fail to find socket because its local address changed. One solution to this problem is to rehash datagram socket if needed. We add a new rehash(struct socket *) method in "struct proto", and implement this method for UDP v4 & v6, using a common helper. This rehashing only takes care of secondary hash table, since primary hash (based on local port only) is not changed. Reported-by: Krzysztof Piotr Oledzki <ole@ans.pl> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Tested-by: Krzysztof Piotr Oledzki <ole@ans.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/datagram.c5
-rw-r--r--net/ipv4/udp.c44
-rw-r--r--net/ipv6/datagram.c7
-rw-r--r--net/ipv6/udp.c10
4 files changed, 64 insertions, 2 deletions
diff --git a/net/ipv4/datagram.c b/net/ipv4/datagram.c
index f0550941df7..721a8a37b45 100644
--- a/net/ipv4/datagram.c
+++ b/net/ipv4/datagram.c
@@ -62,8 +62,11 @@ int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
}
if (!inet->inet_saddr)
inet->inet_saddr = rt->rt_src; /* Update source address */
- if (!inet->inet_rcv_saddr)
+ if (!inet->inet_rcv_saddr) {
inet->inet_rcv_saddr = rt->rt_src;
+ if (sk->sk_prot->rehash)
+ sk->sk_prot->rehash(sk);
+ }
inet->inet_daddr = rt->rt_dst;
inet->inet_dport = usin->sin_port;
sk->sk_state = TCP_ESTABLISHED;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 32e0bef60d0..fb23c2e63b5 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1260,6 +1260,49 @@ void udp_lib_unhash(struct sock *sk)
}
EXPORT_SYMBOL(udp_lib_unhash);
+/*
+ * inet_rcv_saddr was changed, we must rehash secondary hash
+ */
+void udp_lib_rehash(struct sock *sk, u16 newhash)
+{
+ if (sk_hashed(sk)) {
+ struct udp_table *udptable = sk->sk_prot->h.udp_table;
+ struct udp_hslot *hslot, *hslot2, *nhslot2;
+
+ hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
+ nhslot2 = udp_hashslot2(udptable, newhash);
+ udp_sk(sk)->udp_portaddr_hash = newhash;
+ if (hslot2 != nhslot2) {
+ hslot = udp_hashslot(udptable, sock_net(sk),
+ udp_sk(sk)->udp_port_hash);
+ /* we must lock primary chain too */
+ spin_lock_bh(&hslot->lock);
+
+ spin_lock(&hslot2->lock);
+ hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
+ hslot2->count--;
+ spin_unlock(&hslot2->lock);
+
+ spin_lock(&nhslot2->lock);
+ hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+ &nhslot2->head);
+ nhslot2->count++;
+ spin_unlock(&nhslot2->lock);
+
+ spin_unlock_bh(&hslot->lock);
+ }
+ }
+}
+EXPORT_SYMBOL(udp_lib_rehash);
+
+static void udp_v4_rehash(struct sock *sk)
+{
+ u16 new_hash = udp4_portaddr_hash(sock_net(sk),
+ inet_sk(sk)->inet_rcv_saddr,
+ inet_sk(sk)->inet_num);
+ udp_lib_rehash(sk, new_hash);
+}
+
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int rc;
@@ -1843,6 +1886,7 @@ struct proto udp_prot = {
.backlog_rcv = __udp_queue_rcv_skb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
+ .rehash = udp_v4_rehash,
.get_port = udp_v4_get_port,
.memory_allocated = &udp_memory_allocated,
.sysctl_mem = sysctl_udp_mem,
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 7d929a22cbc..ef371aa01ac 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -105,9 +105,12 @@ ipv4_connected:
if (ipv6_addr_any(&np->saddr))
ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
- if (ipv6_addr_any(&np->rcv_saddr))
+ if (ipv6_addr_any(&np->rcv_saddr)) {
ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
&np->rcv_saddr);
+ if (sk->sk_prot->rehash)
+ sk->sk_prot->rehash(sk);
+ }
goto out;
}
@@ -181,6 +184,8 @@ ipv4_connected:
if (ipv6_addr_any(&np->rcv_saddr)) {
ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
inet->inet_rcv_saddr = LOOPBACK4_IPV6;
+ if (sk->sk_prot->rehash)
+ sk->sk_prot->rehash(sk);
}
ip6_dst_store(sk, dst,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1dd1affdead..5acb3560ff1 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -111,6 +111,15 @@ int udp_v6_get_port(struct sock *sk, unsigned short snum)
return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
}
+static void udp_v6_rehash(struct sock *sk)
+{
+ u16 new_hash = udp6_portaddr_hash(sock_net(sk),
+ &inet6_sk(sk)->rcv_saddr,
+ inet_sk(sk)->inet_num);
+
+ udp_lib_rehash(sk, new_hash);
+}
+
static inline int compute_score(struct sock *sk, struct net *net,
unsigned short hnum,
struct in6_addr *saddr, __be16 sport,
@@ -1447,6 +1456,7 @@ struct proto udpv6_prot = {
.backlog_rcv = udpv6_queue_rcv_skb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
+ .rehash = udp_v6_rehash,
.get_port = udp_v6_get_port,
.memory_allocated = &udp_memory_allocated,
.sysctl_mem = sysctl_udp_mem,