[INET]: Generalise tcp_tw_bucket, aka TIME_WAIT sockets

This paves the way to generalise the rest of the sock ID lookup
routines and saves some bytes in TCPv4 TIME_WAIT sockets on distro
kernels (where IPv6 is always built as a module):

[root@qemu ~]# grep tw_sock /proc/slabinfo
tw_sock_TCPv6  0  0  128  31  1
tw_sock_TCP    0  0   96  41  1
[root@qemu ~]#

Now if a protocol wants to use the TIME_WAIT generic infrastructure it
only has to set the sk_prot->twsk_obj_size field with the size of its
inet_timewait_sock derived sock and proto_register will create
sk_prot->twsk_slab, for now its only for INET sockets, but we can
introduce timewait_sock later if some non INET transport protocolo
wants to use this stuff.

Next changesets will take advantage of this new infrastructure to
generalise even more TCP code.

[acme@toy net-2.6.14]$ grep built-in /tmp/before.size /tmp/after.size
/tmp/before.size: 188646   11764    5068  205478   322a6 net/ipv4/built-in.o
/tmp/after.size:  188144   11764    5068  204976   320b0 net/ipv4/built-in.o
[acme@toy net-2.6.14]$

Tested with both IPv4 & IPv6 (::1 (localhost) & ::ffff:172.20.0.1
(qemu host)).

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 64 insertions, 3 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 6fcd6a0ade24..98fa32316e40 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -308,6 +308,41 @@ static inline void inet_sk_copy_descendant(struct sock *sk_to,
 
 #define __ipv6_only_sock(sk)    (inet6_sk(sk)->ipv6only)
 #define ipv6_only_sock(sk)      ((sk)->sk_family == PF_INET6 && __ipv6_only_sock(sk))
+
+#include <linux/tcp.h>
+
+struct tcp6_timewait_sock {
+        struct tcp_timewait_sock tw_v6_sk;
+        struct in6_addr          tw_v6_daddr;
+        struct in6_addr          tw_v6_rcv_saddr;
+};
+
+static inline struct tcp6_timewait_sock *tcp6_twsk(const struct sock *sk)
+{
+        return (struct tcp6_timewait_sock *)sk;
+}
+
+static inline struct in6_addr *__tcp_v6_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;
+}
+
+static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
+{
+        return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
+}
+
+static inline int tcp_twsk_ipv6only(const struct sock *sk)
+{
+        return inet_twsk(sk)->tw_ipv6only;
+}
+
+static inline int tcp_v6_ipv6only(const struct sock *sk)
+{
+        return likely(sk->sk_state != TCP_TIME_WAIT) ?
+                ipv6_only_sock(sk) : tcp_twsk_ipv6only(sk);
+}
 #else
 #define __ipv6_only_sock(sk)    0
 #define ipv6_only_sock(sk)      0
@@ -322,8 +357,19 @@ static inline struct raw6_sock *raw6_sk(const struct sock *sk)
         return NULL;
 }
 
-#endif
+#define __tcp_v6_rcv_saddr(__sk)        NULL
+#define tcp_v6_rcv_saddr(__sk)          NULL
+#define tcp_twsk_ipv6only(__sk)         0
+#define tcp_v6_ipv6only(__sk)           0
+#endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
 
-#endif
+#define INET6_MATCH(__sk, __saddr, __daddr, __ports, __dif)        \
+        (((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports))   && \
+         ((__sk)->sk_family             == AF_INET6)            && \
+         ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr))     && \
+         ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \
+         (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 
-#endif
+#endif /* __KERNEL__ */
+
+#endif /* _IPV6_H */
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index b88fe05fdcbf..5d295b1b3de7 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -179,6 +179,7 @@ struct tcp_info
 #include <linux/skbuff.h>
 #include <linux/ip.h>
 #include <net/sock.h>
+#include <net/inet_timewait_sock.h>
 
 /* This defines a selective acknowledgement block. */
 struct tcp_sack_block {
@@ -387,6 +388,20 @@ static inline struct tcp_sock *tcp_sk(const struct sock *sk)
         return (struct tcp_sock *)sk;
 }
 
+struct tcp_timewait_sock {
+        struct inet_timewait_sock tw_sk;
+        __u32                     tw_rcv_nxt;
+        __u32                     tw_snd_nxt;
+        __u32                     tw_rcv_wnd;
+        __u32                     tw_ts_recent;
+        long                      tw_ts_recent_stamp;
+};
+
+static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
+{
+        return (struct tcp_timewait_sock *)sk;
+}
+
 static inline void *tcp_ca(const struct tcp_sock *tp)
 {
         return (void *) tp->ca_priv;