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authorEric Dumazet <eric.dumazet@gmail.com>2010-09-08 01:08:44 -0400
committerDavid S. Miller <davem@davemloft.net>2010-09-09 00:45:01 -0400
commit719f835853a92f6090258114a72ffe41f09155cd (patch)
treea077b05397bf07a096be7f07b50375c5ed918ac2 /include
parentae2688d59b5f861dc70a091d003773975d2ae7fb (diff)
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 'include')
-rw-r--r--include/net/sock.h1
-rw-r--r--include/net/udp.h1
2 files changed, 2 insertions, 0 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index ac53bfbdfe16..adab9dc58183 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -752,6 +752,7 @@ struct proto {
752 /* Keeping track of sk's, looking them up, and port selection methods. */ 752 /* Keeping track of sk's, looking them up, and port selection methods. */
753 void (*hash)(struct sock *sk); 753 void (*hash)(struct sock *sk);
754 void (*unhash)(struct sock *sk); 754 void (*unhash)(struct sock *sk);
755 void (*rehash)(struct sock *sk);
755 int (*get_port)(struct sock *sk, unsigned short snum); 756 int (*get_port)(struct sock *sk, unsigned short snum);
756 757
757 /* Keeping track of sockets in use */ 758 /* Keeping track of sockets in use */
diff --git a/include/net/udp.h b/include/net/udp.h
index 7abdf305da50..a184d3496b13 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -151,6 +151,7 @@ static inline void udp_lib_hash(struct sock *sk)
151} 151}
152 152
153extern void udp_lib_unhash(struct sock *sk); 153extern void udp_lib_unhash(struct sock *sk);
154extern void udp_lib_rehash(struct sock *sk, u16 new_hash);
154 155
155static inline void udp_lib_close(struct sock *sk, long timeout) 156static inline void udp_lib_close(struct sock *sk, long timeout)
156{ 157{