[INET6_HASHTABLES]: Move inet6_lookup functions to net/ipv6/inet6_hashtables.c

Doing this we allow tcp_diag to support IPV6 even if tcp_diag is compiled
statically and IPV6 is compiled as a module, removing the previous restriction
while not building any IPV6 code if it is not selected.

Now to work on the tcpdiag_register infrastructure and then to rename the whole
thing to inetdiag, reflecting its by then completely generic nature.

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

include/net/inet6_hashtables.h

···
 #ifndef _INET6_HASHTABLES_H
 #define _INET6_HASHTABLES_H
 
+#include <linux/config.h>
+
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+#include <linux/in6.h>
+#include <linux/ipv6.h>
 #include <linux/types.h>
 
-struct in6_addr;
+#include <net/ipv6.h>
+
 struct inet_hashinfo;
+
+/* I have no idea if this is a good hash for v6 or not. -DaveM */
+static inline int inet6_ehashfn(const struct in6_addr *laddr, const u16 lport,
+				const struct in6_addr *faddr, const u16 fport,
+				const int ehash_size)
+{
+	int hashent = (lport ^ fport);
+
+	hashent ^= (laddr->s6_addr32[3] ^ faddr->s6_addr32[3]);
+	hashent ^= hashent >> 16;
+	hashent ^= hashent >> 8;
+	return (hashent & (ehash_size - 1));
+}
+
+static inline int inet6_sk_ehashfn(const struct sock *sk, const int ehash_size)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+	const struct in6_addr *laddr = &np->rcv_saddr;
+	const struct in6_addr *faddr = &np->daddr;
+	const __u16 lport = inet->num;
+	const __u16 fport = inet->dport;
+	return inet6_ehashfn(laddr, lport, faddr, fport, ehash_size);
+}
+
+/*
+ * 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
+ *
+ * The sockhash lock must be held as a reader here.
+ */
+static inline struct sock *
+		__inet6_lookup_established(struct inet_hashinfo *hashinfo,
+					   const struct in6_addr *saddr,
+					   const u16 sport,
+					   const struct in6_addr *daddr,
+					   const u16 hnum,
+					   const int dif)
+{
+	struct sock *sk;
+	const struct hlist_node *node;
+	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
+	/* Optimize here for direct hit, only listening connections can
+	 * have wildcards anyways.
+	 */
+	const int hash = inet6_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) {
+		/* For IPV6 do the cheaper port and family tests first. */
+		if (INET6_MATCH(sk, 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) {
+		const struct inet_timewait_sock *tw = inet_twsk(sk);
+
+		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
+		   sk->sk_family		== PF_INET6) {
+			const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
+
+			if (ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)	&&
+			    ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)	&&
+			    (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
+				goto hit;
+		}
+	}
+	read_unlock(&head->lock);
+	return NULL;
+
+hit:
+	sock_hold(sk);
+	read_unlock(&head->lock);
+	return sk;
+}
+
+extern struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
+					  const struct in6_addr *daddr,
+					  const unsigned short hnum,
+					  const int dif);
+
+static inline struct sock *__inet6_lookup(struct inet_hashinfo *hashinfo,
+					  const struct in6_addr *saddr,
+					  const u16 sport,
+					  const struct in6_addr *daddr,
+					  const u16 hnum,
+					  const int dif)
+{
+	struct sock *sk = __inet6_lookup_established(hashinfo, saddr, sport,
+						     daddr, hnum, dif);
+	if (sk)
+		return sk;
+
+	return inet6_lookup_listener(hashinfo, daddr, hnum, dif);
+}
 
 extern struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
 				 const struct in6_addr *saddr, const u16 sport,
 				 const struct in6_addr *daddr, const u16 dport,
 				 const int dif);
+#endif /* defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) */
 #endif /* _INET6_HASHTABLES_H */

net/ipv4/Kconfig

···
 	---help---
 	  Support for TCP socket monitoring interface used by native Linux
 	  tools such as ss. ss is included in iproute2, currently downloadable
-	  at <http://developer.osdl.org/dev/iproute2>. If you want IPv6 or DCCP
-	  support and have selected IPv6 or DCCP as a module, you need to build
-	  this as a module too.
+	  at <http://developer.osdl.org/dev/iproute2>. 
 	  
 	  If unsure, say Y.
 

net/ipv6/Makefile

···
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
 
 obj-y += exthdrs_core.o
+
+obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o

net/ipv6/inet6_hashtables.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 INET6 transport hashtables
+ *
+ * Authors:	Lotsa people, from code originally in tcp
+ *
+ *	This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+
+#include <linux/module.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/inet_hashtables.h>
+#include <net/inet6_hashtables.h>
+
+struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
+				   const struct in6_addr *daddr,
+				   const unsigned short hnum, const int dif)
+{
+	struct sock *sk;
+	const struct hlist_node *node;
+	struct sock *result = NULL;
+	int score, hiscore = 0;
+
+	read_lock(&hashinfo->lhash_lock);
+	sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
+		if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
+			const struct ipv6_pinfo *np = inet6_sk(sk);
+			
+			score = 1;
+			if (!ipv6_addr_any(&np->rcv_saddr)) {
+				if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
+					continue;
+				score++;
+			}
+			if (sk->sk_bound_dev_if) {
+				if (sk->sk_bound_dev_if != dif)
+					continue;
+				score++;
+			}
+			if (score == 3) {
+				result = sk;
+				break;
+			}
+			if (score > hiscore) {
+				hiscore = score;
+				result = sk;
+			}
+		}
+	}
+	if (result)
+		sock_hold(result);
+	read_unlock(&hashinfo->lhash_lock);
+	return result;
+}
+
+EXPORT_SYMBOL_GPL(inet6_lookup_listener);
+
+struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
+			  const struct in6_addr *saddr, const u16 sport,
+			  const struct in6_addr *daddr, const u16 dport,
+			  const int dif)
+{
+	struct sock *sk;
+
+	local_bh_disable();
+	sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
+	local_bh_enable();
+
+	return sk;
+}
+
+EXPORT_SYMBOL_GPL(inet6_lookup);

net/ipv6/tcp_ipv6.c

···
 
 #include <net/tcp.h>
 #include <net/ndisc.h>
+#include <net/inet6_hashtables.h>
 #include <net/ipv6.h>
 #include <net/transp_v6.h>
 #include <net/addrconf.h>
···
 
 static struct tcp_func ipv6_mapped;
 static struct tcp_func ipv6_specific;
-
-/* I have no idea if this is a good hash for v6 or not. -DaveM */
-static inline int inet6_ehashfn(const struct in6_addr *laddr, const u16 lport,
-				const struct in6_addr *faddr, const u16 fport,
-				const int ehash_size)
-{
-	int hashent = (lport ^ fport);
-
-	hashent ^= (laddr->s6_addr32[3] ^ faddr->s6_addr32[3]);
-	hashent ^= hashent>>16;
-	hashent ^= hashent>>8;
-	return (hashent & (ehash_size - 1));
-}
-
-static inline int inet6_sk_ehashfn(const struct sock *sk, const int ehash_size)
-{
-	const struct inet_sock *inet = inet_sk(sk);
-	const struct ipv6_pinfo *np = inet6_sk(sk);
-	const struct in6_addr *laddr = &np->rcv_saddr;
-	const struct in6_addr *faddr = &np->daddr;
-	const __u16 lport = inet->num;
-	const __u16 fport = inet->dport;
-	return inet6_ehashfn(laddr, lport, faddr, fport, ehash_size);
-}
 
 static inline int tcp_v6_bind_conflict(const struct sock *sk,
 				       const struct inet_bind_bucket *tb)
···
 		local_bh_enable();
 	}
 }
-
-static struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
-					  const struct in6_addr *daddr,
-					  const unsigned short hnum,
-					  const int dif)
-{
-	struct sock *sk;
-	struct hlist_node *node;
-	struct sock *result = NULL;
-	int score, hiscore;
-
-	hiscore=0;
-	read_lock(&hashinfo->lhash_lock);
-	sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
-		if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
-			struct ipv6_pinfo *np = inet6_sk(sk);
-			
-			score = 1;
-			if (!ipv6_addr_any(&np->rcv_saddr)) {
-				if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
-					continue;
-				score++;
-			}
-			if (sk->sk_bound_dev_if) {
-				if (sk->sk_bound_dev_if != dif)
-					continue;
-				score++;
-			}
-			if (score == 3) {
-				result = sk;
-				break;
-			}
-			if (score > hiscore) {
-				hiscore = score;
-				result = sk;
-			}
-		}
-	}
-	if (result)
-		sock_hold(result);
-	read_unlock(&hashinfo->lhash_lock);
-	return result;
-}
-
-/* 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
- *
- * The sockhash lock must be held as a reader here.
- */
-
-static inline struct sock *
-		__inet6_lookup_established(struct inet_hashinfo *hashinfo,
-					   const struct in6_addr *saddr,
-					   const u16 sport,
-					   const struct in6_addr *daddr,
-					   const u16 hnum,
-					   const int dif)
-{
-	struct sock *sk;
-	const struct hlist_node *node;
-	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
-	/* Optimize here for direct hit, only listening connections can
-	 * have wildcards anyways.
-	 */
-	const int hash = inet6_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) {
-		/* For IPV6 do the cheaper port and family tests first. */
-		if (INET6_MATCH(sk, 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) {
-		const struct inet_timewait_sock *tw = inet_twsk(sk);
-
-		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
-		   sk->sk_family		== PF_INET6) {
-			const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
-
-			if (ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)	&&
-			    ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)	&&
-			    (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
-				goto hit;
-		}
-	}
-	read_unlock(&head->lock);
-	return NULL;
-
-hit:
-	sock_hold(sk);
-	read_unlock(&head->lock);
-	return sk;
-}
-
-
-static inline struct sock *__inet6_lookup(struct inet_hashinfo *hashinfo,
-					  const struct in6_addr *saddr,
-					  const u16 sport,
-					  const struct in6_addr *daddr,
-					  const u16 hnum,
-					  const int dif)
-{
-	struct sock *sk = __inet6_lookup_established(hashinfo, saddr, sport,
-						     daddr, hnum, dif);
-	if (sk)
-		return sk;
-
-	return inet6_lookup_listener(hashinfo, daddr, hnum, dif);
-}
-
-inline struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
-				 const struct in6_addr *saddr, const u16 sport,
-				 const struct in6_addr *daddr, const u16 dport,
-				 const int dif)
-{
-	struct sock *sk;
-
-	local_bh_disable();
-	sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
-	local_bh_enable();
-
-	return sk;
-}
-
-EXPORT_SYMBOL_GPL(inet6_lookup);
-
 
 /*
  * Open request hash tables.