[INET]: Generalise the TCP sock ID lookup routines

And also some TIME_WAIT functions.

[acme@toy net-2.6.14]$ grep built-in /tmp/before.size /tmp/after.size
/tmp/before.size: 282955 13122 9312 305389 4a8ed net/ipv4/built-in.o
/tmp/after.size: 281566 13122 9312 304000 4a380 net/ipv4/built-in.o
[acme@toy net-2.6.14]$

I kept them still inlined, will uninline at some point to see what
would be the performance difference.

Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/inet_hashtables.h

···
 #include <net/tcp_states.h>
 
 #include <asm/atomic.h>
+#include <asm/byteorder.h>
 
 /* This is for all connections with a full identity, no wildcards.
  * New scheme, half the table is for TIME_WAIT, the other half is
···
 					   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)
+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;
+	const struct hlist_head *head;
 
 	read_lock(&hashinfo->lhash_lock);
 	head = &hashinfo->listening_hash[inet_lhashfn(hnum)];
···
 	 ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&	\
 	 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #endif /* 64-bit arch */
+
+/*
+ * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
+ * not check it for lookups anymore, thanks Alexey. -DaveM
+ *
+ * Local BH must be disabled here.
+ */
+static inline struct sock *
+	__inet_lookup_established(struct inet_hashinfo *hashinfo,
+				  const u32 saddr, const u16 sport,
+				  const u32 daddr, const u16 hnum,
+				  const int dif)
+{
+	INET_ADDR_COOKIE(acookie, saddr, daddr)
+	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
+	struct sock *sk;
+	const struct hlist_node *node;
+	/* Optimize here for direct hit, only listening connections can
+	 * have wildcards anyways.
+	 */
+	const int hash = inet_ehashfn(daddr, hnum, saddr, sport, hashinfo->ehash_size);
+	struct inet_ehash_bucket *head = &hashinfo->ehash[hash];
+
+	read_lock(&head->lock);
+	sk_for_each(sk, node, &head->chain) {
+		if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif))
+			goto hit; /* You sunk my battleship! */
+	}
+
+	/* Must check for a TIME_WAIT'er before going to listener hash. */
+	sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
+		if (INET_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
+			goto hit;
+	}
+	sk = NULL;
+out:
+	read_unlock(&head->lock);
+	return sk;
+hit:
+	sock_hold(sk);
+	goto out;
+}
+
+static inline struct sock *__inet_lookup(struct inet_hashinfo *hashinfo,
+					 const u32 saddr, const u16 sport,
+					 const u32 daddr, const u16 hnum,
+					 const int dif)
+{
+	struct sock *sk = __inet_lookup_established(hashinfo, saddr, sport, daddr,
+						    hnum, dif);
+	return sk ? : inet_lookup_listener(hashinfo, daddr, hnum, dif);
+}
+
+static inline struct sock *inet_lookup(struct inet_hashinfo *hashinfo,
+				       const u32 saddr, const u16 sport,
+				       const u32 daddr, const u16 dport,
+				       const int dif)
+{
+	struct sock *sk;
+
+	local_bh_disable();
+	sk = __inet_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
+	local_bh_enable();
+
+	return sk;
+}
 #endif /* _INET_HASHTABLES_H */

include/net/inet_timewait_sock.h

···
 
 #include <linux/config.h>
 
+#include <linux/ip.h>
 #include <linux/list.h>
 #include <linux/types.h>
 
···
 #endif
 
 struct inet_bind_bucket;
+struct inet_hashinfo;
 
 /*
  * This is a TIME_WAIT sock. It works around the memory consumption
···
 		kmem_cache_free(tw->tw_prot->twsk_slab, tw);
 	}
 }
+
+extern void __inet_twsk_kill(struct inet_timewait_sock *tw,
+			     struct inet_hashinfo *hashinfo);
+
+extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
+				  struct sock *sk,
+				  struct inet_hashinfo *hashinfo);
 #endif	/* _INET_TIMEWAIT_SOCK_ */

include/net/sock.h

···
 /*
  * Hashed lists helper routines
  */
-static inline struct sock *__sk_head(struct hlist_head *head)
+static inline struct sock *__sk_head(const struct hlist_head *head)
 {
 	return hlist_entry(head->first, struct sock, sk_node);
 }
 
-static inline struct sock *sk_head(struct hlist_head *head)
+static inline struct sock *sk_head(const struct hlist_head *head)
 {
 	return hlist_empty(head) ? NULL : __sk_head(head);
 }
 
-static inline struct sock *sk_next(struct sock *sk)
+static inline struct sock *sk_next(const struct sock *sk)
 {
 	return sk->sk_node.next ?
 		hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
 }
 
-static inline int sk_unhashed(struct sock *sk)
+static inline int sk_unhashed(const struct sock *sk)
 {
 	return hlist_unhashed(&sk->sk_node);
 }
 
-static inline int sk_hashed(struct sock *sk)
+static inline int sk_hashed(const struct sock *sk)
 {
 	return sk->sk_node.pprev != NULL;
 }
···
 struct request_sock_ops;
 
 /* Here is the right place to enable sock refcounting debugging */
-#define SOCK_REFCNT_DEBUG
+//#define SOCK_REFCNT_DEBUG
 
 /* Networking protocol blocks we attach to sockets.
  * socket layer -> transport layer interface

net/ipv4/Makefile

···
 obj-y     := route.o inetpeer.o protocol.o \
 	     ip_input.o ip_fragment.o ip_forward.o ip_options.o \
 	     ip_output.o ip_sockglue.o inet_hashtables.o \
+	     inet_timewait_sock.o \
 	     tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
 	     tcp_minisocks.o tcp_cong.o \
 	     datagram.o raw.o udp.o arp.o icmp.o devinet.o af_inet.o igmp.o \

net/ipv4/inet_hashtables.c

···
 	}
 	return result;
 }
+
+EXPORT_SYMBOL_GPL(__inet_lookup_listener);

net/ipv4/inet_timewait_sock.c

···
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Generic TIME_WAIT sockets functions
+ *
+ *		From code orinally in TCP
+ */
+
+#include <linux/config.h>
+
+#include <net/inet_hashtables.h>
+#include <net/inet_timewait_sock.h>
+
+/* Must be called with locally disabled BHs. */
+void __inet_twsk_kill(struct inet_timewait_sock *tw, struct inet_hashinfo *hashinfo)
+{
+	struct inet_bind_hashbucket *bhead;
+	struct inet_bind_bucket *tb;
+	/* Unlink from established hashes. */
+	struct inet_ehash_bucket *ehead = &hashinfo->ehash[tw->tw_hashent];
+
+	write_lock(&ehead->lock);
+	if (hlist_unhashed(&tw->tw_node)) {
+		write_unlock(&ehead->lock);
+		return;
+	}
+	__hlist_del(&tw->tw_node);
+	sk_node_init(&tw->tw_node);
+	write_unlock(&ehead->lock);
+
+	/* Disassociate with bind bucket. */
+	bhead = &hashinfo->bhash[inet_bhashfn(tw->tw_num, hashinfo->bhash_size)];
+	spin_lock(&bhead->lock);
+	tb = tw->tw_tb;
+	__hlist_del(&tw->tw_bind_node);
+	tw->tw_tb = NULL;
+	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
+	spin_unlock(&bhead->lock);
+#ifdef SOCK_REFCNT_DEBUG
+	if (atomic_read(&tw->tw_refcnt) != 1) {
+		printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n",
+		       tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
+	}
+#endif
+	inet_twsk_put(tw);
+}
+
+/*
+ * Enter the time wait state. This is called with locally disabled BH.
+ * Essentially we whip up a timewait bucket, copy the relevant info into it
+ * from the SK, and mess with hash chains and list linkage.
+ */
+void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
+			   struct inet_hashinfo *hashinfo)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	struct inet_ehash_bucket *ehead = &hashinfo->ehash[sk->sk_hashent];
+	struct inet_bind_hashbucket *bhead;
+	/* Step 1: Put TW into bind hash. Original socket stays there too.
+	   Note, that any socket with inet->num != 0 MUST be bound in
+	   binding cache, even if it is closed.
+	 */
+	bhead = &hashinfo->bhash[inet_bhashfn(inet->num, hashinfo->bhash_size)];
+	spin_lock(&bhead->lock);
+	tw->tw_tb = inet->bind_hash;
+	BUG_TRAP(inet->bind_hash);
+	inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
+	spin_unlock(&bhead->lock);
+
+	write_lock(&ehead->lock);
+
+	/* Step 2: Remove SK from established hash. */
+	if (__sk_del_node_init(sk))
+		sock_prot_dec_use(sk->sk_prot);
+
+	/* Step 3: Hash TW into TIMEWAIT half of established hash table. */
+	inet_twsk_add_node(tw, &(ehead + hashinfo->ehash_size)->chain);
+	atomic_inc(&tw->tw_refcnt);
+
+	write_unlock(&ehead->lock);
+}

net/ipv4/tcp_diag.c

···
 	return -1;
 }
 
-extern struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr, u16 dport,
-				  int dif);
 #ifdef CONFIG_IP_TCPDIAG_IPV6
 extern struct sock *tcp_v6_lookup(struct in6_addr *saddr, u16 sport,
 				  struct in6_addr *daddr, u16 dport,
···
 	struct sk_buff *rep;
 
 	if (req->tcpdiag_family == AF_INET) {
-		sk = tcp_v4_lookup(req->id.tcpdiag_dst[0], req->id.tcpdiag_dport,
-				   req->id.tcpdiag_src[0], req->id.tcpdiag_sport,
-				   req->id.tcpdiag_if);
+		sk = inet_lookup(&tcp_hashinfo, req->id.tcpdiag_dst[0],
+				 req->id.tcpdiag_dport, req->id.tcpdiag_src[0],
+				 req->id.tcpdiag_sport, req->id.tcpdiag_if);
 	}
 #ifdef CONFIG_IP_TCPDIAG_IPV6
 	else if (req->tcpdiag_family == AF_INET6) {

net/ipv4/tcp_ipv4.c

···
 	inet_unhash(&tcp_hashinfo, 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
- *
- * Local BH must be disabled here.
- */
-
-static inline struct sock *__tcp_v4_lookup_established(const u32 saddr,
-						       const u16 sport,
-						       const u32 daddr,
-						       const u16 hnum,
-						       const int dif)
-{
-	struct inet_ehash_bucket *head;
-	INET_ADDR_COOKIE(acookie, saddr, daddr)
-	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
-	struct sock *sk;
-	const struct hlist_node *node;
-	/* Optimize here for direct hit, only listening connections can
-	 * have wildcards anyways.
-	 */
-	const int hash = inet_ehashfn(daddr, hnum, saddr, sport, tcp_hashinfo.ehash_size);
-	head = &tcp_hashinfo.ehash[hash];
-	read_lock(&head->lock);
-	sk_for_each(sk, node, &head->chain) {
-		if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif))
-			goto hit; /* You sunk my battleship! */
-	}
-
-	/* Must check for a TIME_WAIT'er before going to listener hash. */
-	sk_for_each(sk, node, &(head + tcp_hashinfo.ehash_size)->chain) {
-		if (INET_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
-			goto hit;
-	}
-	sk = NULL;
-out:
-	read_unlock(&head->lock);
-	return sk;
-hit:
-	sock_hold(sk);
-	goto out;
-}
-
-static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport,
-					   u32 daddr, u16 hnum, int dif)
-{
-	struct sock *sk = __tcp_v4_lookup_established(saddr, sport,
-						      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,
-				  u16 dport, int dif)
-{
-	struct sock *sk;
-
-	local_bh_disable();
-	sk = __tcp_v4_lookup(saddr, sport, daddr, ntohs(dport), dif);
-	local_bh_enable();
-
-	return sk;
-}
-
-EXPORT_SYMBOL_GPL(tcp_v4_lookup);
-
 static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
 {
 	return secure_tcp_sequence_number(skb->nh.iph->daddr,
···
 		return;
 	}
 
-	sk = tcp_v4_lookup(iph->daddr, th->dest, iph->saddr,
-			   th->source, tcp_v4_iif(skb));
+	sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr,
+			 th->source, tcp_v4_iif(skb));
 	if (!sk) {
 		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
 		return;
···
 	if (req)
 		return tcp_check_req(sk, skb, req, prev);
 
-	nsk = __tcp_v4_lookup_established(skb->nh.iph->saddr,
-					  th->source,
-					  skb->nh.iph->daddr,
-					  ntohs(th->dest),
-					  tcp_v4_iif(skb));
+	nsk = __inet_lookup_established(&tcp_hashinfo, skb->nh.iph->saddr,
+					th->source, skb->nh.iph->daddr,
+					ntohs(th->dest), tcp_v4_iif(skb));
 
 	if (nsk) {
 		if (nsk->sk_state != TCP_TIME_WAIT) {
···
 	TCP_SKB_CB(skb)->flags	 = skb->nh.iph->tos;
 	TCP_SKB_CB(skb)->sacked	 = 0;
 
-	sk = __tcp_v4_lookup(skb->nh.iph->saddr, th->source,
-			     skb->nh.iph->daddr, ntohs(th->dest),
-			     tcp_v4_iif(skb));
+	sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source,
+			   skb->nh.iph->daddr, ntohs(th->dest),
+			   tcp_v4_iif(skb));
 
 	if (!sk)
 		goto no_tcp_socket;

net/ipv4/tcp_minisocks.c

···
 
 int tcp_tw_count;
 
-
-/* Must be called with locally disabled BHs. */
-static void tcp_timewait_kill(struct inet_timewait_sock *tw)
-{
-	struct inet_bind_hashbucket *bhead;
-	struct inet_bind_bucket *tb;
-	/* Unlink from established hashes. */
-	struct inet_ehash_bucket *ehead = &tcp_hashinfo.ehash[tw->tw_hashent];
-
-	write_lock(&ehead->lock);
-	if (hlist_unhashed(&tw->tw_node)) {
-		write_unlock(&ehead->lock);
-		return;
-	}
-	__hlist_del(&tw->tw_node);
-	sk_node_init(&tw->tw_node);
-	write_unlock(&ehead->lock);
-
-	/* Disassociate with bind bucket. */
-	bhead = &tcp_hashinfo.bhash[inet_bhashfn(tw->tw_num, tcp_hashinfo.bhash_size)];
-	spin_lock(&bhead->lock);
-	tb = tw->tw_tb;
-	__hlist_del(&tw->tw_bind_node);
-	tw->tw_tb = NULL;
-	inet_bind_bucket_destroy(tcp_hashinfo.bind_bucket_cachep, tb);
-	spin_unlock(&bhead->lock);
-
-#ifdef SOCK_REFCNT_DEBUG
-	if (atomic_read(&tw->tw_refcnt) != 1) {
-		printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n",
-		       tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
-	}
-#endif
-	inet_twsk_put(tw);
-}
-
 /* 
  * * Main purpose of TIME-WAIT state is to close connection gracefully,
  *   when one of ends sits in LAST-ACK or CLOSING retransmitting FIN
···
 	return TCP_TW_SUCCESS;
 }
 
-/* Enter the time wait state.  This is called with locally disabled BH.
- * Essentially we whip up a timewait bucket, copy the
- * relevant info into it from the SK, and mess with hash chains
- * and list linkage.
- */
-static void __tcp_tw_hashdance(struct sock *sk, struct inet_timewait_sock *tw)
-{
-	const struct inet_sock *inet = inet_sk(sk);
-	struct inet_ehash_bucket *ehead = &tcp_hashinfo.ehash[sk->sk_hashent];
-	struct inet_bind_hashbucket *bhead;
-	/* Step 1: Put TW into bind hash. Original socket stays there too.
-	   Note, that any socket with inet->num != 0 MUST be bound in
-	   binding cache, even if it is closed.
-	 */
-	bhead = &tcp_hashinfo.bhash[inet_bhashfn(inet->num, tcp_hashinfo.bhash_size)];
-	spin_lock(&bhead->lock);
-	tw->tw_tb = inet->bind_hash;
-	BUG_TRAP(inet->bind_hash);
-	inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
-	spin_unlock(&bhead->lock);
-
-	write_lock(&ehead->lock);
-
-	/* Step 2: Remove SK from established hash. */
-	if (__sk_del_node_init(sk))
-		sock_prot_dec_use(sk->sk_prot);
-
-	/* Step 3: Hash TW into TIMEWAIT half of established hash table. */
-	inet_twsk_add_node(tw, &(ehead + tcp_hashinfo.ehash_size)->chain);
-	atomic_inc(&tw->tw_refcnt);
-
-	write_unlock(&ehead->lock);
-}
-
 /* 
  * Move a socket to time-wait or dead fin-wait-2 state.
  */ 
···
 			tw->tw_ipv6only = 0;
 #endif
 		/* Linkage updates. */
-		__tcp_tw_hashdance(sk, tw);
+		__inet_twsk_hashdance(tw, sk, &tcp_hashinfo);
 
 		/* Get the TIME_WAIT timeout firing. */
 		if (timeo < rto)
···
 	inet_twsk_for_each_inmate(tw, node, &tcp_tw_death_row[slot]) {
 		__inet_twsk_del_dead_node(tw);
 		spin_unlock(&tw_death_lock);
-		tcp_timewait_kill(tw);
+		__inet_twsk_kill(tw, &tcp_hashinfo);
 		inet_twsk_put(tw);
 		killed++;
 		spin_lock(&tw_death_lock);
···
 			del_timer(&tcp_tw_timer);
 	}
 	spin_unlock(&tw_death_lock);
-	tcp_timewait_kill(tw);
+	__inet_twsk_kill(tw, &tcp_hashinfo);
 }
 
 /* Short-time timewait calendar */
···
 			inet_twsk_for_each_inmate_safe(tw, node, safe,
 						       &tcp_twcal_row[slot]) {
 				__inet_twsk_del_dead_node(tw);
-				tcp_timewait_kill(tw);
+				__inet_twsk_kill(tw, &tcp_hashinfo);
 				inet_twsk_put(tw);
 				killed++;
 			}