[IPV6]: Introduce inet6_timewait_sock

Out of tcp6_timewait_sock, that now is just an aggregation of
inet_timewait_sock and inet6_timewait_sock, using tw_ipv6_offset in struct
inet_timewait_sock, that is common to the IPv6 transport protocols that use
timewait sockets, like DCCP and TCP.

tw_ipv6_offset plays the struct inet_sock pinfo6 role, i.e. for the generic
code to find the IPv6 area in a timewait sock.

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

Author: Arnaldo Carvalho de Melo

include/linux/ipv6.h

@@ -348,26 +348,36 @@ static inline void inet_sk_copy_descendant(struct sock *sk_to,
 
 #include <linux/tcp.h>
 
+struct inet6_timewait_sock {
+	struct in6_addr tw_v6_daddr;
+	struct in6_addr	tw_v6_rcv_saddr;
+};
+
 struct tcp6_timewait_sock {
-	struct tcp_timewait_sock tw_v6_sk;
-	struct in6_addr		 tw_v6_daddr;
-	struct in6_addr		 tw_v6_rcv_saddr;
+	struct tcp_timewait_sock   tcp6tw_tcp;
+	struct inet6_timewait_sock tcp6tw_inet6;
 };
 
-static inline struct tcp6_timewait_sock *tcp6_twsk(const struct sock *sk)
+static inline u16 inet6_tw_offset(const struct proto *prot)
+{
+	return prot->twsk_obj_size - sizeof(struct inet6_timewait_sock);
+}
+
+static inline struct inet6_timewait_sock *inet6_twsk(const struct sock *sk)
 {
-	return (struct tcp6_timewait_sock *)sk;
+	return (struct inet6_timewait_sock *)(((u8 *)sk) +
+					      inet_twsk(sk)->tw_ipv6_offset);
 }
 
-static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk)
+static inline struct in6_addr *__inet6_rcv_saddr(const struct sock *sk)
 {
 	return likely(sk->sk_state != TCP_TIME_WAIT) ?
-		&inet6_sk(sk)->rcv_saddr : &tcp6_twsk(sk)->tw_v6_rcv_saddr;
+		&inet6_sk(sk)->rcv_saddr : &inet6_twsk(sk)->tw_v6_rcv_saddr;
 }
 
-static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
+static inline struct in6_addr *inet6_rcv_saddr(const struct sock *sk)
 {
-	return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
+	return sk->sk_family == AF_INET6 ? __inet6_rcv_saddr(sk) : NULL;
 }
 
 static inline int inet_v6_ipv6only(const struct sock *sk)
@@ -395,8 +405,8 @@ static inline struct raw6_sock *raw6_sk(const struct sock *sk)
 	return NULL;
 }
 
-#define __tcp_v6_rcv_saddr(__sk)	NULL
-#define tcp_v6_rcv_saddr(__sk)		NULL
+#define __inet6_rcv_saddr(__sk)	NULL
+#define inet6_rcv_saddr(__sk)	NULL
 #define tcp_twsk_ipv6only(__sk)		0
 #define inet_v6_ipv6only(__sk)		0
 #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */

include/net/inet6_hashtables.h

@@ -110,10 +110,10 @@ static inline struct sock *
 
 		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
 		   sk->sk_family		== PF_INET6) {
-			const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
+			const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
 
-			if (ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)	&&
-			    ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)	&&
+			if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	&&
+			    ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr)	&&
 			    (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
 				goto hit;
 		}

include/net/inet_timewait_sock.h

@@ -127,7 +127,8 @@ struct inet_timewait_sock {
 	__u16			tw_num;
 	/* And these are ours. */
 	__u8			tw_ipv6only:1;
-	/* 31 bits hole, try to pack */
+	/* 15 bits hole, try to pack */
+	__u16			tw_ipv6_offset;
 	int			tw_timeout;
 	unsigned long		tw_ttd;
 	struct inet_bind_bucket	*tw_tb;

net/ipv4/inet_diag.c

@@ -112,12 +112,12 @@ static int inet_diag_fill(struct sk_buff *skb, struct sock *sk,
 		r->idiag_inode = 0;
 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
 		if (r->idiag_family == AF_INET6) {
-			const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
+			const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
 
 			ipv6_addr_copy((struct in6_addr *)r->id.idiag_src,
-				       &tcp6tw->tw_v6_rcv_saddr);
+				       &tw6->tw_v6_rcv_saddr);
 			ipv6_addr_copy((struct in6_addr *)r->id.idiag_dst,
-				       &tcp6tw->tw_v6_daddr);
+				       &tw6->tw_v6_daddr);
 		}
 #endif
 		nlh->nlmsg_len = skb->tail - b;

net/ipv4/tcp_minisocks.c

@@ -298,10 +298,12 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 		if (tw->tw_family == PF_INET6) {
 			struct ipv6_pinfo *np = inet6_sk(sk);
-			struct tcp6_timewait_sock *tcp6tw = tcp6_twsk((struct sock *)tw);
+			struct inet6_timewait_sock *tw6;
 
-			ipv6_addr_copy(&tcp6tw->tw_v6_daddr, &np->daddr);
-			ipv6_addr_copy(&tcp6tw->tw_v6_rcv_saddr, &np->rcv_saddr);
+			tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
+			tw6 = inet6_twsk((struct sock *)tw);
+			ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
+			ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
 			tw->tw_ipv6only = np->ipv6only;
 		}
 #endif

net/ipv6/addrconf.c

@@ -1195,7 +1195,7 @@ struct inet6_ifaddr * ipv6_get_ifaddr(struct in6_addr *addr, struct net_device *
 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
 {
 	const struct in6_addr *sk_rcv_saddr6 = &inet6_sk(sk)->rcv_saddr;
-	const struct in6_addr *sk2_rcv_saddr6 = tcp_v6_rcv_saddr(sk2);
+	const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
 	u32 sk_rcv_saddr = inet_sk(sk)->rcv_saddr;
 	u32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
 	int sk_ipv6only = ipv6_only_sock(sk);

net/ipv6/tcp_ipv6.c

@@ -138,14 +138,14 @@ static int __tcp_v6_check_established(struct sock *sk, const __u16 lport,
 
 	/* Check TIME-WAIT sockets first. */
 	sk_for_each(sk2, node, &(head + tcp_hashinfo.ehash_size)->chain) {
-		const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk2);
+		const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);
 
 		tw = inet_twsk(sk2);
 
 		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
 		   sk2->sk_family		== PF_INET6	&&
-		   ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)	&&
-		   ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)	&&
+		   ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	&&
+		   ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr)	&&
 		   sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
 			const struct tcp_timewait_sock *tcptw = tcp_twsk(sk2);
 			struct tcp_sock *tp = tcp_sk(sk);
@@ -1663,14 +1663,14 @@ static void get_timewait6_sock(struct seq_file *seq,
 {
 	struct in6_addr *dest, *src;
 	__u16 destp, srcp;
-	struct tcp6_timewait_sock *tcp6tw = tcp6_twsk((struct sock *)tw);
+	struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
 	int ttd = tw->tw_ttd - jiffies;
 
 	if (ttd < 0)
 		ttd = 0;
 
-	dest = &tcp6tw->tw_v6_daddr;
-	src  = &tcp6tw->tw_v6_rcv_saddr;
+	dest = &tw6->tw_v6_daddr;
+	src  = &tw6->tw_v6_rcv_saddr;
 	destp = ntohs(tw->tw_dport);
 	srcp  = ntohs(tw->tw_sport);