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[INET]: Generalise tcp_v4_lookup_listener
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[acme@toy net-2.6.14]$ grep built-in /tmp/before /tmp/after
/tmp/before: 282560       13122    9312  304994   4a762 net/ipv4/built-in.o
/tmp/after:  282560       13122    9312  304994   4a762 net/ipv4/built-in.o

Will be used in DCCP, not exporting it right now not to get in Adrian
Bunk's exported-but-not-used-on-modules radar 8)

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Arnaldo Carvalho de Melo authored and David S. Miller committed Aug 29, 2005
1 parent 81849d1 commit 33b6223
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Showing 3 changed files with 82 additions and 76 deletions.
36 changes: 36 additions & 0 deletions include/net/inet_hashtables.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,8 +16,10 @@

#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/wait.h>
Expand Down Expand Up @@ -274,4 +276,38 @@ static inline void inet_unhash(struct inet_hashinfo *hashinfo, struct sock *sk)
if (sk->sk_state == TCP_LISTEN)
wake_up(&hashinfo->lhash_wait);
}

extern struct sock *__inet_lookup_listener(const struct hlist_head *head,
const u32 daddr,
const unsigned short hnum,
const int dif);

/* Optimize the common listener case. */
static inline struct sock *inet_lookup_listener(struct inet_hashinfo *hashinfo,
const u32 daddr,
const unsigned short hnum,
const int dif)
{
struct sock *sk = NULL;
struct hlist_head *head;

read_lock(&hashinfo->lhash_lock);
head = &hashinfo->listening_hash[inet_lhashfn(hnum)];
if (!hlist_empty(head)) {
const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));

if (inet->num == hnum && !sk->sk_node.next &&
(!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
(sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
!sk->sk_bound_dev_if)
goto sherry_cache;
sk = __inet_lookup_listener(head, daddr, hnum, dif);
}
if (sk) {
sherry_cache:
sock_hold(sk);
}
read_unlock(&hashinfo->lhash_lock);
return sk;
}
#endif /* _INET_HASHTABLES_H */
41 changes: 41 additions & 0 deletions net/ipv4/inet_hashtables.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,3 +121,44 @@ void inet_listen_wlock(struct inet_hashinfo *hashinfo)
}

EXPORT_SYMBOL(inet_listen_wlock);

/*
* Don't inline this cruft. Here are some nice properties to exploit here. The
* BSD API does not allow a listening sock to specify the remote port nor the
* remote address for the connection. So always assume those are both
* wildcarded during the search since they can never be otherwise.
*/
struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr,
const unsigned short hnum, const int dif)
{
struct sock *result = NULL, *sk;
const struct hlist_node *node;
int hiscore = -1;

sk_for_each(sk, node, head) {
const struct inet_sock *inet = inet_sk(sk);

if (inet->num == hnum && !ipv6_only_sock(sk)) {
const __u32 rcv_saddr = inet->rcv_saddr;
int score = sk->sk_family == PF_INET ? 1 : 0;

if (rcv_saddr) {
if (rcv_saddr != daddr)
continue;
score += 2;
}
if (sk->sk_bound_dev_if) {
if (sk->sk_bound_dev_if != dif)
continue;
score += 2;
}
if (score == 5)
return sk;
if (score > hiscore) {
hiscore = score;
result = sk;
}
}
}
return result;
}
81 changes: 5 additions & 76 deletions net/ipv4/tcp_ipv4.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -238,78 +238,6 @@ void tcp_unhash(struct sock *sk)
inet_unhash(&tcp_hashinfo, sk);
}

/* Don't inline this cruft. Here are some nice properties to
* exploit here. The BSD API does not allow a listening TCP
* to specify the remote port nor the remote address for the
* connection. So always assume those are both wildcarded
* during the search since they can never be otherwise.
*/
static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head,
const u32 daddr,
const unsigned short hnum,
const int dif)
{
struct sock *result = NULL, *sk;
struct hlist_node *node;
int score, hiscore;

hiscore=-1;
sk_for_each(sk, node, head) {
struct inet_sock *inet = inet_sk(sk);

if (inet->num == hnum && !ipv6_only_sock(sk)) {
__u32 rcv_saddr = inet->rcv_saddr;

score = (sk->sk_family == PF_INET ? 1 : 0);
if (rcv_saddr) {
if (rcv_saddr != daddr)
continue;
score+=2;
}
if (sk->sk_bound_dev_if) {
if (sk->sk_bound_dev_if != dif)
continue;
score+=2;
}
if (score == 5)
return sk;
if (score > hiscore) {
hiscore = score;
result = sk;
}
}
}
return result;
}

/* Optimize the common listener case. */
static inline struct sock *tcp_v4_lookup_listener(const u32 daddr,
const unsigned short hnum,
const int dif)
{
struct sock *sk = NULL;
struct hlist_head *head;

read_lock(&tcp_hashinfo.lhash_lock);
head = &tcp_hashinfo.listening_hash[inet_lhashfn(hnum)];
if (!hlist_empty(head)) {
struct inet_sock *inet = inet_sk((sk = __sk_head(head)));

if (inet->num == hnum && !sk->sk_node.next &&
(!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
(sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
!sk->sk_bound_dev_if)
goto sherry_cache;
sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif);
}
if (sk) {
sherry_cache:
sock_hold(sk);
}
read_unlock(&tcp_hashinfo.lhash_lock);
return sk;
}

/* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
* we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
*
Expand Down Expand Up @@ -358,7 +286,7 @@ static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport,
struct sock *sk = __tcp_v4_lookup_established(saddr, sport,
daddr, hnum, dif);

return sk ? : tcp_v4_lookup_listener(daddr, hnum, dif);
return sk ? : inet_lookup_listener(&tcp_hashinfo, daddr, hnum, dif);
}

inline struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr,
Expand Down Expand Up @@ -1641,9 +1569,10 @@ int tcp_v4_rcv(struct sk_buff *skb)
switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
skb, th, skb->len)) {
case TCP_TW_SYN: {
struct sock *sk2 = tcp_v4_lookup_listener(skb->nh.iph->daddr,
ntohs(th->dest),
tcp_v4_iif(skb));
struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
skb->nh.iph->daddr,
ntohs(th->dest),
tcp_v4_iif(skb));
if (sk2) {
tcp_tw_deschedule((struct tcp_tw_bucket *)sk);
tcp_tw_put((struct tcp_tw_bucket *)sk);
Expand Down

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