[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>

4 files changed, 134 insertions, 135 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2f4b1a374bb7..f1a708bf7a97 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -271,8 +271,6 @@ int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
 
 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
 
-kmem_cache_t *tcp_timewait_cachep;
-
 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
 
 int sysctl_tcp_mem[3];
@@ -2264,13 +2262,6 @@ void __init tcp_init(void)
         if (!tcp_hashinfo.bind_bucket_cachep)
                 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
 
-        tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
-                                                sizeof(struct tcp_tw_bucket),
-                                                0, SLAB_HWCACHE_ALIGN,
-                                                NULL, NULL);
-        if (!tcp_timewait_cachep)
-                panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
-
         /* Size and allocate the main established and bind bucket
          * hash tables.
          *
@@ -2363,4 +2354,3 @@ EXPORT_SYMBOL(tcp_sendpage);
 EXPORT_SYMBOL(tcp_setsockopt);
 EXPORT_SYMBOL(tcp_shutdown);
 EXPORT_SYMBOL(tcp_statistics);
-EXPORT_SYMBOL(tcp_timewait_cachep);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 1a89a03c449b..6f2d6f2276b9 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -81,7 +81,7 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
         r->id.tcpdiag_cookie[1] = (u32)(((unsigned long)sk >> 31) >> 1);
 
         if (r->tcpdiag_state == TCP_TIME_WAIT) {
-                struct tcp_tw_bucket *tw = (struct tcp_tw_bucket*)sk;
+                const struct inet_timewait_sock *tw = inet_twsk(sk);
                 long tmo = tw->tw_ttd - jiffies;
                 if (tmo < 0)
                         tmo = 0;
@@ -99,10 +99,12 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
                 r->tcpdiag_inode = 0;
 #ifdef CONFIG_IP_TCPDIAG_IPV6
                 if (r->tcpdiag_family == AF_INET6) {
+                        const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
+
                         ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_src,
-                                       &tw->tw_v6_rcv_saddr);
+                                       &tcp6tw->tw_v6_rcv_saddr);
                         ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_dst,
-                                       &tw->tw_v6_daddr);
+                                       &tcp6tw->tw_v6_daddr);
                 }
 #endif
                 nlh->nlmsg_len = skb->tail - b;
@@ -239,7 +241,7 @@ static int tcpdiag_get_exact(struct sk_buff *in_skb, const struct nlmsghdr *nlh)
 out:
         if (sk) {
                 if (sk->sk_state == TCP_TIME_WAIT)
-                        tcp_tw_put((struct tcp_tw_bucket*)sk);
+                        inet_twsk_put((struct inet_timewait_sock *)sk);
                 else
                         sock_put(sk);
         }
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a678709b36f6..ce423e48ebe0 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -106,7 +106,7 @@ int sysctl_local_port_range[2] = { 1024, 4999 };
 
 static inline int tcp_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb)
 {
-        const u32 sk_rcv_saddr = tcp_v4_rcv_saddr(sk);
+        const u32 sk_rcv_saddr = inet_rcv_saddr(sk);
         struct sock *sk2;
         struct hlist_node *node;
         int reuse = sk->sk_reuse;
@@ -119,7 +119,7 @@ static inline int tcp_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb
                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
                         if (!reuse || !sk2->sk_reuse ||
                             sk2->sk_state == TCP_LISTEN) {
-                                const u32 sk2_rcv_saddr = tcp_v4_rcv_saddr(sk2);
+                                const u32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
                                 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
                                     sk2_rcv_saddr == sk_rcv_saddr)
                                         break;
@@ -251,10 +251,10 @@ static inline struct sock *__tcp_v4_lookup_established(const u32 saddr,
                                                        const int dif)
 {
         struct inet_ehash_bucket *head;
-        TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
-        __u32 ports = TCP_COMBINED_PORTS(sport, hnum);
+        INET_ADDR_COOKIE(acookie, saddr, daddr)
+        const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
         struct sock *sk;
-        struct hlist_node *node;
+        const struct hlist_node *node;
         /* Optimize here for direct hit, only listening connections can
          * have wildcards anyways.
          */
@@ -262,13 +262,13 @@ static inline struct sock *__tcp_v4_lookup_established(const u32 saddr,
         head = &tcp_hashinfo.ehash[hash];
         read_lock(&head->lock);
         sk_for_each(sk, node, &head->chain) {
-                if (TCP_IPV4_MATCH(sk, acookie, saddr, daddr, ports, dif))
+                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 (TCP_IPV4_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
+                if (INET_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
                         goto hit;
         }
         sk = NULL;
@@ -313,27 +313,28 @@ static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
 
 /* called with local bh disabled */
 static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
-                                      struct tcp_tw_bucket **twp)
+                                      struct inet_timewait_sock **twp)
 {
         struct inet_sock *inet = inet_sk(sk);
         u32 daddr = inet->rcv_saddr;
         u32 saddr = inet->daddr;
         int dif = sk->sk_bound_dev_if;
-        TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
-        __u32 ports = TCP_COMBINED_PORTS(inet->dport, lport);
+        INET_ADDR_COOKIE(acookie, saddr, daddr)
+        const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
         const int hash = inet_ehashfn(daddr, lport, saddr, inet->dport, tcp_hashinfo.ehash_size);
         struct inet_ehash_bucket *head = &tcp_hashinfo.ehash[hash];
         struct sock *sk2;
-        struct hlist_node *node;
-        struct tcp_tw_bucket *tw;
+        const struct hlist_node *node;
+        struct inet_timewait_sock *tw;
 
         write_lock(&head->lock);
 
         /* Check TIME-WAIT sockets first. */
         sk_for_each(sk2, node, &(head + tcp_hashinfo.ehash_size)->chain) {
-                tw = (struct tcp_tw_bucket *)sk2;
+                tw = inet_twsk(sk2);
 
-                if (TCP_IPV4_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) {
+                if (INET_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) {
+                        const struct tcp_timewait_sock *tcptw = tcp_twsk(sk2);
                         struct tcp_sock *tp = tcp_sk(sk);
 
                         /* With PAWS, it is safe from the viewpoint
@@ -350,15 +351,15 @@ static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
                            fall back to VJ's scheme and use initial
                            timestamp retrieved from peer table.
                          */
-                        if (tw->tw_ts_recent_stamp &&
+                        if (tcptw->tw_ts_recent_stamp &&
                             (!twp || (sysctl_tcp_tw_reuse &&
                                       xtime.tv_sec -
-                                      tw->tw_ts_recent_stamp > 1))) {
-                                if ((tp->write_seq =
-                                                tw->tw_snd_nxt + 65535 + 2) == 0)
+                                      tcptw->tw_ts_recent_stamp > 1))) {
+                                tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
+                                if (tp->write_seq == 0)
                                         tp->write_seq = 1;
-                                tp->rx_opt.ts_recent       = tw->tw_ts_recent;
-                                tp->rx_opt.ts_recent_stamp = tw->tw_ts_recent_stamp;
+                                tp->rx_opt.ts_recent       = tcptw->tw_ts_recent;
+                                tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
                                 sock_hold(sk2);
                                 goto unique;
                         } else
@@ -369,7 +370,7 @@ static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
 
         /* And established part... */
         sk_for_each(sk2, node, &head->chain) {
-                if (TCP_IPV4_MATCH(sk2, acookie, saddr, daddr, ports, dif))
+                if (INET_MATCH(sk2, acookie, saddr, daddr, ports, dif))
                         goto not_unique;
         }
 
@@ -392,7 +393,7 @@ unique:
                 tcp_tw_deschedule(tw);
                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 
-                tcp_tw_put(tw);
+                inet_twsk_put(tw);
         }
 
         return 0;
@@ -429,7 +430,7 @@ static inline int tcp_v4_hash_connect(struct sock *sk)
                 static u32 hint;
                 u32 offset = hint + connect_port_offset(sk);
                 struct hlist_node *node;
-                struct tcp_tw_bucket *tw = NULL;
+                struct inet_timewait_sock *tw = NULL;
 
                 local_bh_disable();
                 for (i = 1; i <= range; i++) {
@@ -482,7 +483,7 @@ ok:
 
                 if (tw) {
                         tcp_tw_deschedule(tw);
-                        tcp_tw_put(tw);
+                        inet_twsk_put(tw);
                 }
 
                 ret = 0;
@@ -757,7 +758,7 @@ void tcp_v4_err(struct sk_buff *skb, u32 info)
                 return;
         }
         if (sk->sk_state == TCP_TIME_WAIT) {
-                tcp_tw_put((struct tcp_tw_bucket *)sk);
+                inet_twsk_put((struct inet_timewait_sock *)sk);
                 return;
         }
 
@@ -1002,12 +1003,13 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
 
 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 {
-        struct tcp_tw_bucket *tw = (struct tcp_tw_bucket *)sk;
+        struct inet_timewait_sock *tw = inet_twsk(sk);
+        const struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 
-        tcp_v4_send_ack(skb, tw->tw_snd_nxt, tw->tw_rcv_nxt,
-                        tw->tw_rcv_wnd >> tw->tw_rcv_wscale, tw->tw_ts_recent);
+        tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
+                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent);
 
-        tcp_tw_put(tw);
+        inet_twsk_put(tw);
 }
 
 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
@@ -1368,7 +1370,7 @@ static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
                         bh_lock_sock(nsk);
                         return nsk;
                 }
-                tcp_tw_put((struct tcp_tw_bucket *)nsk);
+                inet_twsk_put((struct inet_timewait_sock *)nsk);
                 return NULL;
         }
 
@@ -1557,25 +1559,25 @@ discard_and_relse:
 
 do_time_wait:
         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
-                tcp_tw_put((struct tcp_tw_bucket *) sk);
+                inet_twsk_put((struct inet_timewait_sock *) sk);
                 goto discard_it;
         }
 
         if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
                 TCP_INC_STATS_BH(TCP_MIB_INERRS);
-                tcp_tw_put((struct tcp_tw_bucket *) sk);
+                inet_twsk_put((struct inet_timewait_sock *) sk);
                 goto discard_it;
         }
-        switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
-                                           skb, th, skb->len)) {
+        switch (tcp_timewait_state_process((struct inet_timewait_sock *)sk,
+                                           skb, th)) {
         case TCP_TW_SYN: {
                 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);
+                        tcp_tw_deschedule((struct inet_timewait_sock *)sk);
+                        inet_twsk_put((struct inet_timewait_sock *)sk);
                         sk = sk2;
                         goto process;
                 }
@@ -1639,18 +1641,18 @@ int tcp_v4_remember_stamp(struct sock *sk)
         return 0;
 }
 
-int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw)
+int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
 {
-        struct inet_peer *peer = NULL;
-
-        peer = inet_getpeer(tw->tw_daddr, 1);
+        struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
 
         if (peer) {
-                if ((s32)(peer->tcp_ts - tw->tw_ts_recent) <= 0 ||
+                const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
+
+                if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
                     (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
-                     peer->tcp_ts_stamp <= tw->tw_ts_recent_stamp)) {
-                        peer->tcp_ts_stamp = tw->tw_ts_recent_stamp;
-                        peer->tcp_ts = tw->tw_ts_recent;
+                     peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
+                        peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
+                        peer->tcp_ts       = tcptw->tw_ts_recent;
                 }
                 inet_putpeer(peer);
                 return 1;
@@ -1758,13 +1760,13 @@ EXPORT_SYMBOL(tcp_v4_destroy_sock);
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCP sock list dumping. */
 
-static inline struct tcp_tw_bucket *tw_head(struct hlist_head *head)
+static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
 {
         return hlist_empty(head) ? NULL :
-                list_entry(head->first, struct tcp_tw_bucket, tw_node);
+                list_entry(head->first, struct inet_timewait_sock, tw_node);
 }
 
-static inline struct tcp_tw_bucket *tw_next(struct tcp_tw_bucket *tw)
+static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
 {
         return tw->tw_node.next ?
                 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
@@ -1860,7 +1862,7 @@ static void *established_get_first(struct seq_file *seq)
         for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
                 struct sock *sk;
                 struct hlist_node *node;
-                struct tcp_tw_bucket *tw;
+                struct inet_timewait_sock *tw;
 
                 /* We can reschedule _before_ having picked the target: */
                 cond_resched_softirq();
@@ -1874,8 +1876,8 @@ static void *established_get_first(struct seq_file *seq)
                         goto out;
                 }
                 st->state = TCP_SEQ_STATE_TIME_WAIT;
-                tw_for_each(tw, node,
-                            &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) {
+                inet_twsk_for_each(tw, node,
+                                   &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) {
                         if (tw->tw_family != st->family) {
                                 continue;
                         }
@@ -1892,7 +1894,7 @@ out:
 static void *established_get_next(struct seq_file *seq, void *cur)
 {
         struct sock *sk = cur;
-        struct tcp_tw_bucket *tw;
+        struct inet_timewait_sock *tw;
         struct hlist_node *node;
         struct tcp_iter_state* st = seq->private;
 
@@ -2159,7 +2161,7 @@ static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
                 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
 }
 
-static void get_timewait4_sock(struct tcp_tw_bucket *tw, char *tmpbuf, int i)
+static void get_timewait4_sock(struct inet_timewait_sock *tw, char *tmpbuf, int i)
 {
         unsigned int dest, src;
         __u16 destp, srcp;
@@ -2261,6 +2263,7 @@ struct proto tcp_prot = {
         .sysctl_rmem            = sysctl_tcp_rmem,
         .max_header             = MAX_TCP_HEADER,
         .obj_size               = sizeof(struct tcp_sock),
+        .twsk_obj_size          = sizeof(struct tcp_timewait_sock),
         .rsk_prot               = &tcp_request_sock_ops,
 };
 
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index f29e2f6ebe1b..5b5a49335fbb 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -41,7 +41,7 @@ int sysctl_tcp_max_tw_buckets = NR_FILE*2;
 int sysctl_tcp_syncookies = SYNC_INIT; 
 int sysctl_tcp_abort_on_overflow;
 
-static void tcp_tw_schedule(struct tcp_tw_bucket *tw, int timeo);
+static void tcp_tw_schedule(struct inet_timewait_sock *tw, int timeo);
 
 static __inline__ int tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win)
 {
@@ -58,7 +58,7 @@ int tcp_tw_count;
 
 
 /* Must be called with locally disabled BHs. */
-static void tcp_timewait_kill(struct tcp_tw_bucket *tw)
+static void tcp_timewait_kill(struct inet_timewait_sock *tw)
 {
         struct inet_bind_hashbucket *bhead;
         struct inet_bind_bucket *tb;
@@ -85,11 +85,11 @@ static void tcp_timewait_kill(struct tcp_tw_bucket *tw)
 
 #ifdef SOCK_REFCNT_DEBUG
         if (atomic_read(&tw->tw_refcnt) != 1) {
-                printk(KERN_DEBUG "tw_bucket %p refcnt=%d\n", tw,
-                       atomic_read(&tw->tw_refcnt));
+                printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n",
+                       tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
         }
 #endif
-        tcp_tw_put(tw);
+        inet_twsk_put(tw);
 }
 
 /* 
@@ -121,19 +121,20 @@ static void tcp_timewait_kill(struct tcp_tw_bucket *tw)
  * to avoid misread sequence numbers, states etc.  --ANK
  */
 enum tcp_tw_status
-tcp_timewait_state_process(struct tcp_tw_bucket *tw, struct sk_buff *skb,
-                           struct tcphdr *th, unsigned len)
+tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
+                           const struct tcphdr *th)
 {
+        struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
         struct tcp_options_received tmp_opt;
         int paws_reject = 0;
 
         tmp_opt.saw_tstamp = 0;
-        if (th->doff > (sizeof(struct tcphdr) >> 2) && tw->tw_ts_recent_stamp) {
+        if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
                 tcp_parse_options(skb, &tmp_opt, 0);
 
                 if (tmp_opt.saw_tstamp) {
-                        tmp_opt.ts_recent          = tw->tw_ts_recent;
-                        tmp_opt.ts_recent_stamp = tw->tw_ts_recent_stamp;
+                        tmp_opt.ts_recent       = tcptw->tw_ts_recent;
+                        tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
                         paws_reject = tcp_paws_check(&tmp_opt, th->rst);
                 }
         }
@@ -144,20 +145,20 @@ tcp_timewait_state_process(struct tcp_tw_bucket *tw, struct sk_buff *skb,
                 /* Out of window, send ACK */
                 if (paws_reject ||
                     !tcp_in_window(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq,
-                                   tw->tw_rcv_nxt,
-                                   tw->tw_rcv_nxt + tw->tw_rcv_wnd))
+                                   tcptw->tw_rcv_nxt,
+                                   tcptw->tw_rcv_nxt + tcptw->tw_rcv_wnd))
                         return TCP_TW_ACK;
 
                 if (th->rst)
                         goto kill;
 
-                if (th->syn && !before(TCP_SKB_CB(skb)->seq, tw->tw_rcv_nxt))
+                if (th->syn && !before(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt))
                         goto kill_with_rst;
 
                 /* Dup ACK? */
-                if (!after(TCP_SKB_CB(skb)->end_seq, tw->tw_rcv_nxt) ||
+                if (!after(TCP_SKB_CB(skb)->end_seq, tcptw->tw_rcv_nxt) ||
                     TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq) {
-                        tcp_tw_put(tw);
+                        inet_twsk_put(tw);
                         return TCP_TW_SUCCESS;
                 }
 
@@ -165,19 +166,19 @@ tcp_timewait_state_process(struct tcp_tw_bucket *tw, struct sk_buff *skb,
                  * reset.
                  */
                 if (!th->fin ||
-                    TCP_SKB_CB(skb)->end_seq != tw->tw_rcv_nxt + 1) {
+                    TCP_SKB_CB(skb)->end_seq != tcptw->tw_rcv_nxt + 1) {
 kill_with_rst:
                         tcp_tw_deschedule(tw);
-                        tcp_tw_put(tw);
+                        inet_twsk_put(tw);
                         return TCP_TW_RST;
                 }
 
                 /* FIN arrived, enter true time-wait state. */
-                tw->tw_substate = TCP_TIME_WAIT;
-                tw->tw_rcv_nxt  = TCP_SKB_CB(skb)->end_seq;
+                tw->tw_substate   = TCP_TIME_WAIT;
+                tcptw->tw_rcv_nxt = TCP_SKB_CB(skb)->end_seq;
                 if (tmp_opt.saw_tstamp) {
-                        tw->tw_ts_recent_stamp  = xtime.tv_sec;
-                        tw->tw_ts_recent        = tmp_opt.rcv_tsval;
+                        tcptw->tw_ts_recent_stamp = xtime.tv_sec;
+                        tcptw->tw_ts_recent       = tmp_opt.rcv_tsval;
                 }
 
                 /* I am shamed, but failed to make it more elegant.
@@ -186,7 +187,7 @@ kill_with_rst:
                  * do not undertsnad recycling in any case, it not
                  * a big problem in practice. --ANK */
                 if (tw->tw_family == AF_INET &&
-                    sysctl_tcp_tw_recycle && tw->tw_ts_recent_stamp &&
+                    sysctl_tcp_tw_recycle && tcptw->tw_ts_recent_stamp &&
                     tcp_v4_tw_remember_stamp(tw))
                         tcp_tw_schedule(tw, tw->tw_timeout);
                 else
@@ -212,7 +213,7 @@ kill_with_rst:
          */
 
         if (!paws_reject &&
-            (TCP_SKB_CB(skb)->seq == tw->tw_rcv_nxt &&
+            (TCP_SKB_CB(skb)->seq == tcptw->tw_rcv_nxt &&
              (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq || th->rst))) {
                 /* In window segment, it may be only reset or bare ack. */
 
@@ -224,18 +225,18 @@ kill_with_rst:
                         if (sysctl_tcp_rfc1337 == 0) {
 kill:
                                 tcp_tw_deschedule(tw);
-                                tcp_tw_put(tw);
+                                inet_twsk_put(tw);
                                 return TCP_TW_SUCCESS;
                         }
                 }
                 tcp_tw_schedule(tw, TCP_TIMEWAIT_LEN);
 
                 if (tmp_opt.saw_tstamp) {
-                        tw->tw_ts_recent        = tmp_opt.rcv_tsval;
-                        tw->tw_ts_recent_stamp  = xtime.tv_sec;
+                        tcptw->tw_ts_recent       = tmp_opt.rcv_tsval;
+                        tcptw->tw_ts_recent_stamp = xtime.tv_sec;
                 }
 
-                tcp_tw_put(tw);
+                inet_twsk_put(tw);
                 return TCP_TW_SUCCESS;
         }
 
@@ -257,9 +258,10 @@ kill:
          */
 
         if (th->syn && !th->rst && !th->ack && !paws_reject &&
-            (after(TCP_SKB_CB(skb)->seq, tw->tw_rcv_nxt) ||
-             (tmp_opt.saw_tstamp && (s32)(tw->tw_ts_recent - tmp_opt.rcv_tsval) < 0))) {
-                u32 isn = tw->tw_snd_nxt + 65535 + 2;
+            (after(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt) ||
+             (tmp_opt.saw_tstamp &&
+              (s32)(tcptw->tw_ts_recent - tmp_opt.rcv_tsval) < 0))) {
+                u32 isn = tcptw->tw_snd_nxt + 65535 + 2;
                 if (isn == 0)
                         isn++;
                 TCP_SKB_CB(skb)->when = isn;
@@ -284,7 +286,7 @@ kill:
                  */
                 return TCP_TW_ACK;
         }
-        tcp_tw_put(tw);
+        inet_twsk_put(tw);
         return TCP_TW_SUCCESS;
 }
 
@@ -293,7 +295,7 @@ kill:
  * relevant info into it from the SK, and mess with hash chains
  * and list linkage.
  */
-static void __tcp_tw_hashdance(struct sock *sk, struct tcp_tw_bucket *tw)
+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];
@@ -306,7 +308,7 @@ static void __tcp_tw_hashdance(struct sock *sk, struct tcp_tw_bucket *tw)
         spin_lock(&bhead->lock);
         tw->tw_tb = inet->bind_hash;
         BUG_TRAP(inet->bind_hash);
-        tw_add_bind_node(tw, &tw->tw_tb->owners);
+        inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
         spin_unlock(&bhead->lock);
 
         write_lock(&ehead->lock);
@@ -316,7 +318,7 @@ static void __tcp_tw_hashdance(struct sock *sk, struct tcp_tw_bucket *tw)
                 sock_prot_dec_use(sk->sk_prot);
 
         /* Step 3: Hash TW into TIMEWAIT half of established hash table. */
-        tw_add_node(tw, &(ehead + tcp_hashinfo.ehash_size)->chain);
+        inet_twsk_add_node(tw, &(ehead + tcp_hashinfo.ehash_size)->chain);
         atomic_inc(&tw->tw_refcnt);
 
         write_unlock(&ehead->lock);
@@ -327,19 +329,23 @@ static void __tcp_tw_hashdance(struct sock *sk, struct tcp_tw_bucket *tw)
  */ 
 void tcp_time_wait(struct sock *sk, int state, int timeo)
 {
-        struct tcp_tw_bucket *tw = NULL;
-        struct tcp_sock *tp = tcp_sk(sk);
+        struct inet_timewait_sock *tw = NULL;
+        const struct tcp_sock *tp = tcp_sk(sk);
         int recycle_ok = 0;
 
         if (sysctl_tcp_tw_recycle && tp->rx_opt.ts_recent_stamp)
                 recycle_ok = tp->af_specific->remember_stamp(sk);
 
         if (tcp_tw_count < sysctl_tcp_max_tw_buckets)
-                tw = kmem_cache_alloc(tcp_timewait_cachep, SLAB_ATOMIC);
+                tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_slab, SLAB_ATOMIC);
+
+        if (tw != NULL) {
+                struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
+                const struct inet_sock *inet = inet_sk(sk);
+                const int rto = (tp->rto << 2) - (tp->rto >> 1);
 
-        if(tw != NULL) {
-                struct inet_sock *inet = inet_sk(sk);
-                int rto = (tp->rto<<2) - (tp->rto>>1);
+                /* Remember our protocol */
+                tw->tw_prot             = sk->sk_prot_creator;
 
                 /* Give us an identity. */
                 tw->tw_daddr            = inet->daddr;
@@ -356,25 +362,23 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
                 atomic_set(&tw->tw_refcnt, 1);
 
                 tw->tw_hashent          = sk->sk_hashent;
-                tw->tw_rcv_nxt          = tp->rcv_nxt;
-                tw->tw_snd_nxt          = tp->snd_nxt;
-                tw->tw_rcv_wnd          = tcp_receive_window(tp);
-                tw->tw_ts_recent        = tp->rx_opt.ts_recent;
-                tw->tw_ts_recent_stamp  = tp->rx_opt.ts_recent_stamp;
-                tw_dead_node_init(tw);
+                tcptw->tw_rcv_nxt       = tp->rcv_nxt;
+                tcptw->tw_snd_nxt       = tp->snd_nxt;
+                tcptw->tw_rcv_wnd       = tcp_receive_window(tp);
+                tcptw->tw_ts_recent     = tp->rx_opt.ts_recent;
+                tcptw->tw_ts_recent_stamp = tp->rx_opt.ts_recent_stamp;
+                inet_twsk_dead_node_init(tw);
 
 #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);
 
-                        ipv6_addr_copy(&tw->tw_v6_daddr, &np->daddr);
-                        ipv6_addr_copy(&tw->tw_v6_rcv_saddr, &np->rcv_saddr);
-                        tw->tw_v6_ipv6only = np->ipv6only;
-                } else {
-                        memset(&tw->tw_v6_daddr, 0, sizeof(tw->tw_v6_daddr));
-                        memset(&tw->tw_v6_rcv_saddr, 0, sizeof(tw->tw_v6_rcv_saddr));
-                        tw->tw_v6_ipv6only = 0;
-                }
+                        ipv6_addr_copy(&tcp6tw->tw_v6_daddr, &np->daddr);
+                        ipv6_addr_copy(&tcp6tw->tw_v6_rcv_saddr, &np->rcv_saddr);
+                        tw->tw_ipv6only = np->ipv6only;
+                } else
+                        tw->tw_ipv6only = 0;
 #endif
                 /* Linkage updates. */
                 __tcp_tw_hashdance(sk, tw);
@@ -392,7 +396,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
                 }
 
                 tcp_tw_schedule(tw, timeo);
-                tcp_tw_put(tw);
+                inet_twsk_put(tw);
         } else {
                 /* Sorry, if we're out of memory, just CLOSE this
                  * socket up.  We've got bigger problems than
@@ -427,7 +431,7 @@ static u32 twkill_thread_slots;
 /* Returns non-zero if quota exceeded.  */
 static int tcp_do_twkill_work(int slot, unsigned int quota)
 {
-        struct tcp_tw_bucket *tw;
+        struct inet_timewait_sock *tw;
         struct hlist_node *node;
         unsigned int killed;
         int ret;
@@ -441,11 +445,11 @@ static int tcp_do_twkill_work(int slot, unsigned int quota)
         killed = 0;
         ret = 0;
 rescan:
-        tw_for_each_inmate(tw, node, &tcp_tw_death_row[slot]) {
-                __tw_del_dead_node(tw);
+        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);
-                tcp_tw_put(tw);
+                inet_twsk_put(tw);
                 killed++;
                 spin_lock(&tw_death_lock);
                 if (killed > quota) {
@@ -531,11 +535,11 @@ static void twkill_work(void *dummy)
  */
 
 /* This is for handling early-kills of TIME_WAIT sockets. */
-void tcp_tw_deschedule(struct tcp_tw_bucket *tw)
+void tcp_tw_deschedule(struct inet_timewait_sock *tw)
 {
         spin_lock(&tw_death_lock);
-        if (tw_del_dead_node(tw)) {
-                tcp_tw_put(tw);
+        if (inet_twsk_del_dead_node(tw)) {
+                inet_twsk_put(tw);
                 if (--tcp_tw_count == 0)
                         del_timer(&tcp_tw_timer);
         }
@@ -552,7 +556,7 @@ static struct timer_list tcp_twcal_timer =
                 TIMER_INITIALIZER(tcp_twcal_tick, 0, 0);
 static struct hlist_head tcp_twcal_row[TCP_TW_RECYCLE_SLOTS];
 
-static void tcp_tw_schedule(struct tcp_tw_bucket *tw, int timeo)
+static void tcp_tw_schedule(struct inet_timewait_sock *tw, const int timeo)
 {
         struct hlist_head *list;
         int slot;
@@ -586,7 +590,7 @@ static void tcp_tw_schedule(struct tcp_tw_bucket *tw, int timeo)
         spin_lock(&tw_death_lock);
 
         /* Unlink it, if it was scheduled */
-        if (tw_del_dead_node(tw))
+        if (inet_twsk_del_dead_node(tw))
                 tcp_tw_count--;
         else
                 atomic_inc(&tw->tw_refcnt);
@@ -644,13 +648,13 @@ void tcp_twcal_tick(unsigned long dummy)
         for (n=0; n<TCP_TW_RECYCLE_SLOTS; n++) {
                 if (time_before_eq(j, now)) {
                         struct hlist_node *node, *safe;
-                        struct tcp_tw_bucket *tw;
+                        struct inet_timewait_sock *tw;
 
-                        tw_for_each_inmate_safe(tw, node, safe,
-                                           &tcp_twcal_row[slot]) {
-                                __tw_del_dead_node(tw);
+                        inet_twsk_for_each_inmate_safe(tw, node, safe,
+                                                       &tcp_twcal_row[slot]) {
+                                __inet_twsk_del_dead_node(tw);
                                 tcp_timewait_kill(tw);
-                                tcp_tw_put(tw);
+                                inet_twsk_put(tw);
                                 killed++;
                         }
                 } else {