Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
new file mode 100644
index 0000000..3ac6659
--- /dev/null
+++ b/net/ipv4/tcp_ipv4.c
@@ -0,0 +1,2663 @@
+/*
+ * 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.
+ *
+ * Implementation of the Transmission Control Protocol(TCP).
+ *
+ * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $
+ *
+ * IPv4 specific functions
+ *
+ *
+ * code split from:
+ * linux/ipv4/tcp.c
+ * linux/ipv4/tcp_input.c
+ * linux/ipv4/tcp_output.c
+ *
+ * See tcp.c for author information
+ *
+ * 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.
+ */
+
+/*
+ * Changes:
+ * David S. Miller : New socket lookup architecture.
+ * This code is dedicated to John Dyson.
+ * David S. Miller : Change semantics of established hash,
+ * half is devoted to TIME_WAIT sockets
+ * and the rest go in the other half.
+ * Andi Kleen : Add support for syncookies and fixed
+ * some bugs: ip options weren't passed to
+ * the TCP layer, missed a check for an
+ * ACK bit.
+ * Andi Kleen : Implemented fast path mtu discovery.
+ * Fixed many serious bugs in the
+ * open_request handling and moved
+ * most of it into the af independent code.
+ * Added tail drop and some other bugfixes.
+ * Added new listen sematics.
+ * Mike McLagan : Routing by source
+ * Juan Jose Ciarlante: ip_dynaddr bits
+ * Andi Kleen: various fixes.
+ * Vitaly E. Lavrov : Transparent proxy revived after year
+ * coma.
+ * Andi Kleen : Fix new listen.
+ * Andi Kleen : Fix accept error reporting.
+ * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
+ * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
+ * a single port at the same time.
+ */
+
+#include <linux/config.h>
+
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/cache.h>
+#include <linux/jhash.h>
+#include <linux/init.h>
+#include <linux/times.h>
+
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <net/ipv6.h>
+#include <net/inet_common.h>
+#include <net/xfrm.h>
+
+#include <linux/inet.h>
+#include <linux/ipv6.h>
+#include <linux/stddef.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+extern int sysctl_ip_dynaddr;
+int sysctl_tcp_tw_reuse;
+int sysctl_tcp_low_latency;
+
+/* Check TCP sequence numbers in ICMP packets. */
+#define ICMP_MIN_LENGTH 8
+
+/* Socket used for sending RSTs */
+static struct socket *tcp_socket;
+
+void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
+ struct sk_buff *skb);
+
+struct tcp_hashinfo __cacheline_aligned tcp_hashinfo = {
+ .__tcp_lhash_lock = RW_LOCK_UNLOCKED,
+ .__tcp_lhash_users = ATOMIC_INIT(0),
+ .__tcp_lhash_wait
+ = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.__tcp_lhash_wait),
+ .__tcp_portalloc_lock = SPIN_LOCK_UNLOCKED
+};
+
+/*
+ * This array holds the first and last local port number.
+ * For high-usage systems, use sysctl to change this to
+ * 32768-61000
+ */
+int sysctl_local_port_range[2] = { 1024, 4999 };
+int tcp_port_rover = 1024 - 1;
+
+static __inline__ int tcp_hashfn(__u32 laddr, __u16 lport,
+ __u32 faddr, __u16 fport)
+{
+ int h = (laddr ^ lport) ^ (faddr ^ fport);
+ h ^= h >> 16;
+ h ^= h >> 8;
+ return h & (tcp_ehash_size - 1);
+}
+
+static __inline__ int tcp_sk_hashfn(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ __u32 laddr = inet->rcv_saddr;
+ __u16 lport = inet->num;
+ __u32 faddr = inet->daddr;
+ __u16 fport = inet->dport;
+
+ return tcp_hashfn(laddr, lport, faddr, fport);
+}
+
+/* Allocate and initialize a new TCP local port bind bucket.
+ * The bindhash mutex for snum's hash chain must be held here.
+ */
+struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
+ unsigned short snum)
+{
+ struct tcp_bind_bucket *tb = kmem_cache_alloc(tcp_bucket_cachep,
+ SLAB_ATOMIC);
+ if (tb) {
+ tb->port = snum;
+ tb->fastreuse = 0;
+ INIT_HLIST_HEAD(&tb->owners);
+ hlist_add_head(&tb->node, &head->chain);
+ }
+ return tb;
+}
+
+/* Caller must hold hashbucket lock for this tb with local BH disabled */
+void tcp_bucket_destroy(struct tcp_bind_bucket *tb)
+{
+ if (hlist_empty(&tb->owners)) {
+ __hlist_del(&tb->node);
+ kmem_cache_free(tcp_bucket_cachep, tb);
+ }
+}
+
+/* Caller must disable local BH processing. */
+static __inline__ void __tcp_inherit_port(struct sock *sk, struct sock *child)
+{
+ struct tcp_bind_hashbucket *head =
+ &tcp_bhash[tcp_bhashfn(inet_sk(child)->num)];
+ struct tcp_bind_bucket *tb;
+
+ spin_lock(&head->lock);
+ tb = tcp_sk(sk)->bind_hash;
+ sk_add_bind_node(child, &tb->owners);
+ tcp_sk(child)->bind_hash = tb;
+ spin_unlock(&head->lock);
+}
+
+inline void tcp_inherit_port(struct sock *sk, struct sock *child)
+{
+ local_bh_disable();
+ __tcp_inherit_port(sk, child);
+ local_bh_enable();
+}
+
+void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
+ unsigned short snum)
+{
+ inet_sk(sk)->num = snum;
+ sk_add_bind_node(sk, &tb->owners);
+ tcp_sk(sk)->bind_hash = tb;
+}
+
+static inline int tcp_bind_conflict(struct sock *sk, struct tcp_bind_bucket *tb)
+{
+ const u32 sk_rcv_saddr = tcp_v4_rcv_saddr(sk);
+ struct sock *sk2;
+ struct hlist_node *node;
+ int reuse = sk->sk_reuse;
+
+ sk_for_each_bound(sk2, node, &tb->owners) {
+ if (sk != sk2 &&
+ !tcp_v6_ipv6only(sk2) &&
+ (!sk->sk_bound_dev_if ||
+ !sk2->sk_bound_dev_if ||
+ 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);
+ if (!sk2_rcv_saddr || !sk_rcv_saddr ||
+ sk2_rcv_saddr == sk_rcv_saddr)
+ break;
+ }
+ }
+ }
+ return node != NULL;
+}
+
+/* Obtain a reference to a local port for the given sock,
+ * if snum is zero it means select any available local port.
+ */
+static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
+{
+ struct tcp_bind_hashbucket *head;
+ struct hlist_node *node;
+ struct tcp_bind_bucket *tb;
+ int ret;
+
+ local_bh_disable();
+ if (!snum) {
+ int low = sysctl_local_port_range[0];
+ int high = sysctl_local_port_range[1];
+ int remaining = (high - low) + 1;
+ int rover;
+
+ spin_lock(&tcp_portalloc_lock);
+ rover = tcp_port_rover;
+ do {
+ rover++;
+ if (rover < low || rover > high)
+ rover = low;
+ head = &tcp_bhash[tcp_bhashfn(rover)];
+ spin_lock(&head->lock);
+ tb_for_each(tb, node, &head->chain)
+ if (tb->port == rover)
+ goto next;
+ break;
+ next:
+ spin_unlock(&head->lock);
+ } while (--remaining > 0);
+ tcp_port_rover = rover;
+ spin_unlock(&tcp_portalloc_lock);
+
+ /* Exhausted local port range during search? */
+ ret = 1;
+ if (remaining <= 0)
+ goto fail;
+
+ /* OK, here is the one we will use. HEAD is
+ * non-NULL and we hold it's mutex.
+ */
+ snum = rover;
+ } else {
+ head = &tcp_bhash[tcp_bhashfn(snum)];
+ spin_lock(&head->lock);
+ tb_for_each(tb, node, &head->chain)
+ if (tb->port == snum)
+ goto tb_found;
+ }
+ tb = NULL;
+ goto tb_not_found;
+tb_found:
+ if (!hlist_empty(&tb->owners)) {
+ if (sk->sk_reuse > 1)
+ goto success;
+ if (tb->fastreuse > 0 &&
+ sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
+ goto success;
+ } else {
+ ret = 1;
+ if (tcp_bind_conflict(sk, tb))
+ goto fail_unlock;
+ }
+ }
+tb_not_found:
+ ret = 1;
+ if (!tb && (tb = tcp_bucket_create(head, snum)) == NULL)
+ goto fail_unlock;
+ if (hlist_empty(&tb->owners)) {
+ if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
+ tb->fastreuse = 1;
+ else
+ tb->fastreuse = 0;
+ } else if (tb->fastreuse &&
+ (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
+ tb->fastreuse = 0;
+success:
+ if (!tcp_sk(sk)->bind_hash)
+ tcp_bind_hash(sk, tb, snum);
+ BUG_TRAP(tcp_sk(sk)->bind_hash == tb);
+ ret = 0;
+
+fail_unlock:
+ spin_unlock(&head->lock);
+fail:
+ local_bh_enable();
+ return ret;
+}
+
+/* Get rid of any references to a local port held by the
+ * given sock.
+ */
+static void __tcp_put_port(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct tcp_bind_hashbucket *head = &tcp_bhash[tcp_bhashfn(inet->num)];
+ struct tcp_bind_bucket *tb;
+
+ spin_lock(&head->lock);
+ tb = tcp_sk(sk)->bind_hash;
+ __sk_del_bind_node(sk);
+ tcp_sk(sk)->bind_hash = NULL;
+ inet->num = 0;
+ tcp_bucket_destroy(tb);
+ spin_unlock(&head->lock);
+}
+
+void tcp_put_port(struct sock *sk)
+{
+ local_bh_disable();
+ __tcp_put_port(sk);
+ local_bh_enable();
+}
+
+/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
+ * Look, when several writers sleep and reader wakes them up, all but one
+ * immediately hit write lock and grab all the cpus. Exclusive sleep solves
+ * this, _but_ remember, it adds useless work on UP machines (wake up each
+ * exclusive lock release). It should be ifdefed really.
+ */
+
+void tcp_listen_wlock(void)
+{
+ write_lock(&tcp_lhash_lock);
+
+ if (atomic_read(&tcp_lhash_users)) {
+ DEFINE_WAIT(wait);
+
+ for (;;) {
+ prepare_to_wait_exclusive(&tcp_lhash_wait,
+ &wait, TASK_UNINTERRUPTIBLE);
+ if (!atomic_read(&tcp_lhash_users))
+ break;
+ write_unlock_bh(&tcp_lhash_lock);
+ schedule();
+ write_lock_bh(&tcp_lhash_lock);
+ }
+
+ finish_wait(&tcp_lhash_wait, &wait);
+ }
+}
+
+static __inline__ void __tcp_v4_hash(struct sock *sk, const int listen_possible)
+{
+ struct hlist_head *list;
+ rwlock_t *lock;
+
+ BUG_TRAP(sk_unhashed(sk));
+ if (listen_possible && sk->sk_state == TCP_LISTEN) {
+ list = &tcp_listening_hash[tcp_sk_listen_hashfn(sk)];
+ lock = &tcp_lhash_lock;
+ tcp_listen_wlock();
+ } else {
+ list = &tcp_ehash[(sk->sk_hashent = tcp_sk_hashfn(sk))].chain;
+ lock = &tcp_ehash[sk->sk_hashent].lock;
+ write_lock(lock);
+ }
+ __sk_add_node(sk, list);
+ sock_prot_inc_use(sk->sk_prot);
+ write_unlock(lock);
+ if (listen_possible && sk->sk_state == TCP_LISTEN)
+ wake_up(&tcp_lhash_wait);
+}
+
+static void tcp_v4_hash(struct sock *sk)
+{
+ if (sk->sk_state != TCP_CLOSE) {
+ local_bh_disable();
+ __tcp_v4_hash(sk, 1);
+ local_bh_enable();
+ }
+}
+
+void tcp_unhash(struct sock *sk)
+{
+ rwlock_t *lock;
+
+ if (sk_unhashed(sk))
+ goto ende;
+
+ if (sk->sk_state == TCP_LISTEN) {
+ local_bh_disable();
+ tcp_listen_wlock();
+ lock = &tcp_lhash_lock;
+ } else {
+ struct tcp_ehash_bucket *head = &tcp_ehash[sk->sk_hashent];
+ lock = &head->lock;
+ write_lock_bh(&head->lock);
+ }
+
+ if (__sk_del_node_init(sk))
+ sock_prot_dec_use(sk->sk_prot);
+ write_unlock_bh(lock);
+
+ ende:
+ if (sk->sk_state == TCP_LISTEN)
+ wake_up(&tcp_lhash_wait);
+}
+
+/* Don't inline this cruft. Here are some nice properties to
+ * exploit here. The BSD API does not allow a listening TCP
+ * to specify the remote port nor the remote address for the
+ * connection. So always assume those are both wildcarded
+ * during the search since they can never be otherwise.
+ */
+static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head, u32 daddr,
+ unsigned short hnum, int dif)
+{
+ struct sock *result = NULL, *sk;
+ struct hlist_node *node;
+ int score, hiscore;
+
+ hiscore=-1;
+ sk_for_each(sk, node, head) {
+ struct inet_sock *inet = inet_sk(sk);
+
+ if (inet->num == hnum && !ipv6_only_sock(sk)) {
+ __u32 rcv_saddr = inet->rcv_saddr;
+
+ score = (sk->sk_family == PF_INET ? 1 : 0);
+ if (rcv_saddr) {
+ if (rcv_saddr != daddr)
+ continue;
+ score+=2;
+ }
+ if (sk->sk_bound_dev_if) {
+ if (sk->sk_bound_dev_if != dif)
+ continue;
+ score+=2;
+ }
+ if (score == 5)
+ return sk;
+ if (score > hiscore) {
+ hiscore = score;
+ result = sk;
+ }
+ }
+ }
+ return result;
+}
+
+/* Optimize the common listener case. */
+static inline struct sock *tcp_v4_lookup_listener(u32 daddr,
+ unsigned short hnum, int dif)
+{
+ struct sock *sk = NULL;
+ struct hlist_head *head;
+
+ read_lock(&tcp_lhash_lock);
+ head = &tcp_listening_hash[tcp_lhashfn(hnum)];
+ if (!hlist_empty(head)) {
+ struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
+
+ if (inet->num == hnum && !sk->sk_node.next &&
+ (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
+ (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
+ !sk->sk_bound_dev_if)
+ goto sherry_cache;
+ sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif);
+ }
+ if (sk) {
+sherry_cache:
+ sock_hold(sk);
+ }
+ read_unlock(&tcp_lhash_lock);
+ return 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(u32 saddr, u16 sport,
+ u32 daddr, u16 hnum,
+ int dif)
+{
+ struct tcp_ehash_bucket *head;
+ TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
+ __u32 ports = TCP_COMBINED_PORTS(sport, hnum);
+ struct sock *sk;
+ struct hlist_node *node;
+ /* Optimize here for direct hit, only listening connections can
+ * have wildcards anyways.
+ */
+ int hash = tcp_hashfn(daddr, hnum, saddr, sport);
+ head = &tcp_ehash[hash];
+ read_lock(&head->lock);
+ sk_for_each(sk, node, &head->chain) {
+ if (TCP_IPV4_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_ehash_size)->chain) {
+ if (TCP_IPV4_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 ? : tcp_v4_lookup_listener(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,
+ skb->nh.iph->saddr,
+ skb->h.th->dest,
+ skb->h.th->source);
+}
+
+/* called with local bh disabled */
+static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
+ struct tcp_tw_bucket **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);
+ int hash = tcp_hashfn(daddr, lport, saddr, inet->dport);
+ struct tcp_ehash_bucket *head = &tcp_ehash[hash];
+ struct sock *sk2;
+ struct hlist_node *node;
+ struct tcp_tw_bucket *tw;
+
+ write_lock(&head->lock);
+
+ /* Check TIME-WAIT sockets first. */
+ sk_for_each(sk2, node, &(head + tcp_ehash_size)->chain) {
+ tw = (struct tcp_tw_bucket *)sk2;
+
+ if (TCP_IPV4_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) {
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ /* With PAWS, it is safe from the viewpoint
+ of data integrity. Even without PAWS it
+ is safe provided sequence spaces do not
+ overlap i.e. at data rates <= 80Mbit/sec.
+
+ Actually, the idea is close to VJ's one,
+ only timestamp cache is held not per host,
+ but per port pair and TW bucket is used
+ as state holder.
+
+ If TW bucket has been already destroyed we
+ fall back to VJ's scheme and use initial
+ timestamp retrieved from peer table.
+ */
+ if (tw->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)
+ tp->write_seq = 1;
+ tp->rx_opt.ts_recent = tw->tw_ts_recent;
+ tp->rx_opt.ts_recent_stamp = tw->tw_ts_recent_stamp;
+ sock_hold(sk2);
+ goto unique;
+ } else
+ goto not_unique;
+ }
+ }
+ tw = NULL;
+
+ /* And established part... */
+ sk_for_each(sk2, node, &head->chain) {
+ if (TCP_IPV4_MATCH(sk2, acookie, saddr, daddr, ports, dif))
+ goto not_unique;
+ }
+
+unique:
+ /* Must record num and sport now. Otherwise we will see
+ * in hash table socket with a funny identity. */
+ inet->num = lport;
+ inet->sport = htons(lport);
+ sk->sk_hashent = hash;
+ BUG_TRAP(sk_unhashed(sk));
+ __sk_add_node(sk, &head->chain);
+ sock_prot_inc_use(sk->sk_prot);
+ write_unlock(&head->lock);
+
+ if (twp) {
+ *twp = tw;
+ NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+ } else if (tw) {
+ /* Silly. Should hash-dance instead... */
+ tcp_tw_deschedule(tw);
+ NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+
+ tcp_tw_put(tw);
+ }
+
+ return 0;
+
+not_unique:
+ write_unlock(&head->lock);
+ return -EADDRNOTAVAIL;
+}
+
+static inline u32 connect_port_offset(const struct sock *sk)
+{
+ const struct inet_sock *inet = inet_sk(sk);
+
+ return secure_tcp_port_ephemeral(inet->rcv_saddr, inet->daddr,
+ inet->dport);
+}
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+static inline int tcp_v4_hash_connect(struct sock *sk)
+{
+ unsigned short snum = inet_sk(sk)->num;
+ struct tcp_bind_hashbucket *head;
+ struct tcp_bind_bucket *tb;
+ int ret;
+
+ if (!snum) {
+ int low = sysctl_local_port_range[0];
+ int high = sysctl_local_port_range[1];
+ int range = high - low;
+ int i;
+ int port;
+ static u32 hint;
+ u32 offset = hint + connect_port_offset(sk);
+ struct hlist_node *node;
+ struct tcp_tw_bucket *tw = NULL;
+
+ local_bh_disable();
+ for (i = 1; i <= range; i++) {
+ port = low + (i + offset) % range;
+ head = &tcp_bhash[tcp_bhashfn(port)];
+ spin_lock(&head->lock);
+
+ /* Does not bother with rcv_saddr checks,
+ * because the established check is already
+ * unique enough.
+ */
+ tb_for_each(tb, node, &head->chain) {
+ if (tb->port == port) {
+ BUG_TRAP(!hlist_empty(&tb->owners));
+ if (tb->fastreuse >= 0)
+ goto next_port;
+ if (!__tcp_v4_check_established(sk,
+ port,
+ &tw))
+ goto ok;
+ goto next_port;
+ }
+ }
+
+ tb = tcp_bucket_create(head, port);
+ if (!tb) {
+ spin_unlock(&head->lock);
+ break;
+ }
+ tb->fastreuse = -1;
+ goto ok;
+
+ next_port:
+ spin_unlock(&head->lock);
+ }
+ local_bh_enable();
+
+ return -EADDRNOTAVAIL;
+
+ok:
+ hint += i;
+
+ /* Head lock still held and bh's disabled */
+ tcp_bind_hash(sk, tb, port);
+ if (sk_unhashed(sk)) {
+ inet_sk(sk)->sport = htons(port);
+ __tcp_v4_hash(sk, 0);
+ }
+ spin_unlock(&head->lock);
+
+ if (tw) {
+ tcp_tw_deschedule(tw);
+ tcp_tw_put(tw);
+ }
+
+ ret = 0;
+ goto out;
+ }
+
+ head = &tcp_bhash[tcp_bhashfn(snum)];
+ tb = tcp_sk(sk)->bind_hash;
+ spin_lock_bh(&head->lock);
+ if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
+ __tcp_v4_hash(sk, 0);
+ spin_unlock_bh(&head->lock);
+ return 0;
+ } else {
+ spin_unlock(&head->lock);
+ /* No definite answer... Walk to established hash table */
+ ret = __tcp_v4_check_established(sk, snum, NULL);
+out:
+ local_bh_enable();
+ return ret;
+ }
+}
+
+/* This will initiate an outgoing connection. */
+int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
+ struct rtable *rt;
+ u32 daddr, nexthop;
+ int tmp;
+ int err;
+
+ if (addr_len < sizeof(struct sockaddr_in))
+ return -EINVAL;
+
+ if (usin->sin_family != AF_INET)
+ return -EAFNOSUPPORT;
+
+ nexthop = daddr = usin->sin_addr.s_addr;
+ if (inet->opt && inet->opt->srr) {
+ if (!daddr)
+ return -EINVAL;
+ nexthop = inet->opt->faddr;
+ }
+
+ tmp = ip_route_connect(&rt, nexthop, inet->saddr,
+ RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
+ IPPROTO_TCP,
+ inet->sport, usin->sin_port, sk);
+ if (tmp < 0)
+ return tmp;
+
+ if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
+ ip_rt_put(rt);
+ return -ENETUNREACH;
+ }
+
+ if (!inet->opt || !inet->opt->srr)
+ daddr = rt->rt_dst;
+
+ if (!inet->saddr)
+ inet->saddr = rt->rt_src;
+ inet->rcv_saddr = inet->saddr;
+
+ if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
+ /* Reset inherited state */
+ tp->rx_opt.ts_recent = 0;
+ tp->rx_opt.ts_recent_stamp = 0;
+ tp->write_seq = 0;
+ }
+
+ if (sysctl_tcp_tw_recycle &&
+ !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
+ struct inet_peer *peer = rt_get_peer(rt);
+
+ /* VJ's idea. We save last timestamp seen from
+ * the destination in peer table, when entering state TIME-WAIT
+ * and initialize rx_opt.ts_recent from it, when trying new connection.
+ */
+
+ if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
+ tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
+ tp->rx_opt.ts_recent = peer->tcp_ts;
+ }
+ }
+
+ inet->dport = usin->sin_port;
+ inet->daddr = daddr;
+
+ tp->ext_header_len = 0;
+ if (inet->opt)
+ tp->ext_header_len = inet->opt->optlen;
+
+ tp->rx_opt.mss_clamp = 536;
+
+ /* Socket identity is still unknown (sport may be zero).
+ * However we set state to SYN-SENT and not releasing socket
+ * lock select source port, enter ourselves into the hash tables and
+ * complete initialization after this.
+ */
+ tcp_set_state(sk, TCP_SYN_SENT);
+ err = tcp_v4_hash_connect(sk);
+ if (err)
+ goto failure;
+
+ err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
+ if (err)
+ goto failure;
+
+ /* OK, now commit destination to socket. */
+ __sk_dst_set(sk, &rt->u.dst);
+ tcp_v4_setup_caps(sk, &rt->u.dst);
+
+ if (!tp->write_seq)
+ tp->write_seq = secure_tcp_sequence_number(inet->saddr,
+ inet->daddr,
+ inet->sport,
+ usin->sin_port);
+
+ inet->id = tp->write_seq ^ jiffies;
+
+ err = tcp_connect(sk);
+ rt = NULL;
+ if (err)
+ goto failure;
+
+ return 0;
+
+failure:
+ /* This unhashes the socket and releases the local port, if necessary. */
+ tcp_set_state(sk, TCP_CLOSE);
+ ip_rt_put(rt);
+ sk->sk_route_caps = 0;
+ inet->dport = 0;
+ return err;
+}
+
+static __inline__ int tcp_v4_iif(struct sk_buff *skb)
+{
+ return ((struct rtable *)skb->dst)->rt_iif;
+}
+
+static __inline__ u32 tcp_v4_synq_hash(u32 raddr, u16 rport, u32 rnd)
+{
+ return (jhash_2words(raddr, (u32) rport, rnd) & (TCP_SYNQ_HSIZE - 1));
+}
+
+static struct open_request *tcp_v4_search_req(struct tcp_sock *tp,
+ struct open_request ***prevp,
+ __u16 rport,
+ __u32 raddr, __u32 laddr)
+{
+ struct tcp_listen_opt *lopt = tp->listen_opt;
+ struct open_request *req, **prev;
+
+ for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport, lopt->hash_rnd)];
+ (req = *prev) != NULL;
+ prev = &req->dl_next) {
+ if (req->rmt_port == rport &&
+ req->af.v4_req.rmt_addr == raddr &&
+ req->af.v4_req.loc_addr == laddr &&
+ TCP_INET_FAMILY(req->class->family)) {
+ BUG_TRAP(!req->sk);
+ *prevp = prev;
+ break;
+ }
+ }
+
+ return req;
+}
+
+static void tcp_v4_synq_add(struct sock *sk, struct open_request *req)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_listen_opt *lopt = tp->listen_opt;
+ u32 h = tcp_v4_synq_hash(req->af.v4_req.rmt_addr, req->rmt_port, lopt->hash_rnd);
+
+ req->expires = jiffies + TCP_TIMEOUT_INIT;
+ req->retrans = 0;
+ req->sk = NULL;
+ req->dl_next = lopt->syn_table[h];
+
+ write_lock(&tp->syn_wait_lock);
+ lopt->syn_table[h] = req;
+ write_unlock(&tp->syn_wait_lock);
+
+ tcp_synq_added(sk);
+}
+
+
+/*
+ * This routine does path mtu discovery as defined in RFC1191.
+ */
+static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph,
+ u32 mtu)
+{
+ struct dst_entry *dst;
+ struct inet_sock *inet = inet_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
+ * send out by Linux are always <576bytes so they should go through
+ * unfragmented).
+ */
+ if (sk->sk_state == TCP_LISTEN)
+ return;
+
+ /* We don't check in the destentry if pmtu discovery is forbidden
+ * on this route. We just assume that no packet_to_big packets
+ * are send back when pmtu discovery is not active.
+ * There is a small race when the user changes this flag in the
+ * route, but I think that's acceptable.
+ */
+ if ((dst = __sk_dst_check(sk, 0)) == NULL)
+ return;
+
+ dst->ops->update_pmtu(dst, mtu);
+
+ /* Something is about to be wrong... Remember soft error
+ * for the case, if this connection will not able to recover.
+ */
+ if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
+ sk->sk_err_soft = EMSGSIZE;
+
+ mtu = dst_mtu(dst);
+
+ if (inet->pmtudisc != IP_PMTUDISC_DONT &&
+ tp->pmtu_cookie > mtu) {
+ tcp_sync_mss(sk, mtu);
+
+ /* Resend the TCP packet because it's
+ * clear that the old packet has been
+ * dropped. This is the new "fast" path mtu
+ * discovery.
+ */
+ tcp_simple_retransmit(sk);
+ } /* else let the usual retransmit timer handle it */
+}
+
+/*
+ * This routine is called by the ICMP module when it gets some
+ * sort of error condition. If err < 0 then the socket should
+ * be closed and the error returned to the user. If err > 0
+ * it's just the icmp type << 8 | icmp code. After adjustment
+ * header points to the first 8 bytes of the tcp header. We need
+ * to find the appropriate port.
+ *
+ * The locking strategy used here is very "optimistic". When
+ * someone else accesses the socket the ICMP is just dropped
+ * and for some paths there is no check at all.
+ * A more general error queue to queue errors for later handling
+ * is probably better.
+ *
+ */
+
+void tcp_v4_err(struct sk_buff *skb, u32 info)
+{
+ struct iphdr *iph = (struct iphdr *)skb->data;
+ struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
+ struct tcp_sock *tp;
+ struct inet_sock *inet;
+ int type = skb->h.icmph->type;
+ int code = skb->h.icmph->code;
+ struct sock *sk;
+ __u32 seq;
+ int err;
+
+ if (skb->len < (iph->ihl << 2) + 8) {
+ ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+ return;
+ }
+
+ sk = tcp_v4_lookup(iph->daddr, th->dest, iph->saddr,
+ th->source, tcp_v4_iif(skb));
+ if (!sk) {
+ ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+ return;
+ }
+ if (sk->sk_state == TCP_TIME_WAIT) {
+ tcp_tw_put((struct tcp_tw_bucket *)sk);
+ return;
+ }
+
+ bh_lock_sock(sk);
+ /* If too many ICMPs get dropped on busy
+ * servers this needs to be solved differently.
+ */
+ if (sock_owned_by_user(sk))
+ NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
+
+ if (sk->sk_state == TCP_CLOSE)
+ goto out;
+
+ tp = tcp_sk(sk);
+ seq = ntohl(th->seq);
+ if (sk->sk_state != TCP_LISTEN &&
+ !between(seq, tp->snd_una, tp->snd_nxt)) {
+ NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
+ goto out;
+ }
+
+ switch (type) {
+ case ICMP_SOURCE_QUENCH:
+ /* Just silently ignore these. */
+ goto out;
+ case ICMP_PARAMETERPROB:
+ err = EPROTO;
+ break;
+ case ICMP_DEST_UNREACH:
+ if (code > NR_ICMP_UNREACH)
+ goto out;
+
+ if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
+ if (!sock_owned_by_user(sk))
+ do_pmtu_discovery(sk, iph, info);
+ goto out;
+ }
+
+ err = icmp_err_convert[code].errno;
+ break;
+ case ICMP_TIME_EXCEEDED:
+ err = EHOSTUNREACH;
+ break;
+ default:
+ goto out;
+ }
+
+ switch (sk->sk_state) {
+ struct open_request *req, **prev;
+ case TCP_LISTEN:
+ if (sock_owned_by_user(sk))
+ goto out;
+
+ req = tcp_v4_search_req(tp, &prev, th->dest,
+ iph->daddr, iph->saddr);
+ if (!req)
+ goto out;
+
+ /* ICMPs are not backlogged, hence we cannot get
+ an established socket here.
+ */
+ BUG_TRAP(!req->sk);
+
+ if (seq != req->snt_isn) {
+ NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
+ goto out;
+ }
+
+ /*
+ * Still in SYN_RECV, just remove it silently.
+ * There is no good way to pass the error to the newly
+ * created socket, and POSIX does not want network
+ * errors returned from accept().
+ */
+ tcp_synq_drop(sk, req, prev);
+ goto out;
+
+ case TCP_SYN_SENT:
+ case TCP_SYN_RECV: /* Cannot happen.
+ It can f.e. if SYNs crossed.
+ */
+ if (!sock_owned_by_user(sk)) {
+ TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
+ sk->sk_err = err;
+
+ sk->sk_error_report(sk);
+
+ tcp_done(sk);
+ } else {
+ sk->sk_err_soft = err;
+ }
+ goto out;
+ }
+
+ /* If we've already connected we will keep trying
+ * until we time out, or the user gives up.
+ *
+ * rfc1122 4.2.3.9 allows to consider as hard errors
+ * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
+ * but it is obsoleted by pmtu discovery).
+ *
+ * Note, that in modern internet, where routing is unreliable
+ * and in each dark corner broken firewalls sit, sending random
+ * errors ordered by their masters even this two messages finally lose
+ * their original sense (even Linux sends invalid PORT_UNREACHs)
+ *
+ * Now we are in compliance with RFCs.
+ * --ANK (980905)
+ */
+
+ inet = inet_sk(sk);
+ if (!sock_owned_by_user(sk) && inet->recverr) {
+ sk->sk_err = err;
+ sk->sk_error_report(sk);
+ } else { /* Only an error on timeout */
+ sk->sk_err_soft = err;
+ }
+
+out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+/* This routine computes an IPv4 TCP checksum. */
+void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
+ struct sk_buff *skb)
+{
+ struct inet_sock *inet = inet_sk(sk);
+
+ if (skb->ip_summed == CHECKSUM_HW) {
+ th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0);
+ skb->csum = offsetof(struct tcphdr, check);
+ } else {
+ th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr,
+ csum_partial((char *)th,
+ th->doff << 2,
+ skb->csum));
+ }
+}
+
+/*
+ * This routine will send an RST to the other tcp.
+ *
+ * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
+ * for reset.
+ * Answer: if a packet caused RST, it is not for a socket
+ * existing in our system, if it is matched to a socket,
+ * it is just duplicate segment or bug in other side's TCP.
+ * So that we build reply only basing on parameters
+ * arrived with segment.
+ * Exception: precedence violation. We do not implement it in any case.
+ */
+
+static void tcp_v4_send_reset(struct sk_buff *skb)
+{
+ struct tcphdr *th = skb->h.th;
+ struct tcphdr rth;
+ struct ip_reply_arg arg;
+
+ /* Never send a reset in response to a reset. */
+ if (th->rst)
+ return;
+
+ if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
+ return;
+
+ /* Swap the send and the receive. */
+ memset(&rth, 0, sizeof(struct tcphdr));
+ rth.dest = th->source;
+ rth.source = th->dest;
+ rth.doff = sizeof(struct tcphdr) / 4;
+ rth.rst = 1;
+
+ if (th->ack) {
+ rth.seq = th->ack_seq;
+ } else {
+ rth.ack = 1;
+ rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
+ skb->len - (th->doff << 2));
+ }
+
+ memset(&arg, 0, sizeof arg);
+ arg.iov[0].iov_base = (unsigned char *)&rth;
+ arg.iov[0].iov_len = sizeof rth;
+ arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
+ skb->nh.iph->saddr, /*XXX*/
+ sizeof(struct tcphdr), IPPROTO_TCP, 0);
+ arg.csumoffset = offsetof(struct tcphdr, check) / 2;
+
+ ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth);
+
+ TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
+ TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
+}
+
+/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
+ outside socket context is ugly, certainly. What can I do?
+ */
+
+static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
+ u32 win, u32 ts)
+{
+ struct tcphdr *th = skb->h.th;
+ struct {
+ struct tcphdr th;
+ u32 tsopt[3];
+ } rep;
+ struct ip_reply_arg arg;
+
+ memset(&rep.th, 0, sizeof(struct tcphdr));
+ memset(&arg, 0, sizeof arg);
+
+ arg.iov[0].iov_base = (unsigned char *)&rep;
+ arg.iov[0].iov_len = sizeof(rep.th);
+ if (ts) {
+ rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
+ (TCPOPT_TIMESTAMP << 8) |
+ TCPOLEN_TIMESTAMP);
+ rep.tsopt[1] = htonl(tcp_time_stamp);
+ rep.tsopt[2] = htonl(ts);
+ arg.iov[0].iov_len = sizeof(rep);
+ }
+
+ /* Swap the send and the receive. */
+ rep.th.dest = th->source;
+ rep.th.source = th->dest;
+ rep.th.doff = arg.iov[0].iov_len / 4;
+ rep.th.seq = htonl(seq);
+ rep.th.ack_seq = htonl(ack);
+ rep.th.ack = 1;
+ rep.th.window = htons(win);
+
+ arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
+ skb->nh.iph->saddr, /*XXX*/
+ arg.iov[0].iov_len, IPPROTO_TCP, 0);
+ arg.csumoffset = offsetof(struct tcphdr, check) / 2;
+
+ ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
+
+ TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
+}
+
+static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_tw_bucket *tw = (struct tcp_tw_bucket *)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_tw_put(tw);
+}
+
+static void tcp_v4_or_send_ack(struct sk_buff *skb, struct open_request *req)
+{
+ tcp_v4_send_ack(skb, req->snt_isn + 1, req->rcv_isn + 1, req->rcv_wnd,
+ req->ts_recent);
+}
+
+static struct dst_entry* tcp_v4_route_req(struct sock *sk,
+ struct open_request *req)
+{
+ struct rtable *rt;
+ struct ip_options *opt = req->af.v4_req.opt;
+ struct flowi fl = { .oif = sk->sk_bound_dev_if,
+ .nl_u = { .ip4_u =
+ { .daddr = ((opt && opt->srr) ?
+ opt->faddr :
+ req->af.v4_req.rmt_addr),
+ .saddr = req->af.v4_req.loc_addr,
+ .tos = RT_CONN_FLAGS(sk) } },
+ .proto = IPPROTO_TCP,
+ .uli_u = { .ports =
+ { .sport = inet_sk(sk)->sport,
+ .dport = req->rmt_port } } };
+
+ if (ip_route_output_flow(&rt, &fl, sk, 0)) {
+ IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
+ return NULL;
+ }
+ if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) {
+ ip_rt_put(rt);
+ IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
+ return NULL;
+ }
+ return &rt->u.dst;
+}
+
+/*
+ * Send a SYN-ACK after having received an ACK.
+ * This still operates on a open_request only, not on a big
+ * socket.
+ */
+static int tcp_v4_send_synack(struct sock *sk, struct open_request *req,
+ struct dst_entry *dst)
+{
+ int err = -1;
+ struct sk_buff * skb;
+
+ /* First, grab a route. */
+ if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
+ goto out;
+
+ skb = tcp_make_synack(sk, dst, req);
+
+ if (skb) {
+ struct tcphdr *th = skb->h.th;
+
+ th->check = tcp_v4_check(th, skb->len,
+ req->af.v4_req.loc_addr,
+ req->af.v4_req.rmt_addr,
+ csum_partial((char *)th, skb->len,
+ skb->csum));
+
+ err = ip_build_and_send_pkt(skb, sk, req->af.v4_req.loc_addr,
+ req->af.v4_req.rmt_addr,
+ req->af.v4_req.opt);
+ if (err == NET_XMIT_CN)
+ err = 0;
+ }
+
+out:
+ dst_release(dst);
+ return err;
+}
+
+/*
+ * IPv4 open_request destructor.
+ */
+static void tcp_v4_or_free(struct open_request *req)
+{
+ if (req->af.v4_req.opt)
+ kfree(req->af.v4_req.opt);
+}
+
+static inline void syn_flood_warning(struct sk_buff *skb)
+{
+ static unsigned long warntime;
+
+ if (time_after(jiffies, (warntime + HZ * 60))) {
+ warntime = jiffies;
+ printk(KERN_INFO
+ "possible SYN flooding on port %d. Sending cookies.\n",
+ ntohs(skb->h.th->dest));
+ }
+}
+
+/*
+ * Save and compile IPv4 options into the open_request if needed.
+ */
+static inline struct ip_options *tcp_v4_save_options(struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct ip_options *opt = &(IPCB(skb)->opt);
+ struct ip_options *dopt = NULL;
+
+ if (opt && opt->optlen) {
+ int opt_size = optlength(opt);
+ dopt = kmalloc(opt_size, GFP_ATOMIC);
+ if (dopt) {
+ if (ip_options_echo(dopt, skb)) {
+ kfree(dopt);
+ dopt = NULL;
+ }
+ }
+ }
+ return dopt;
+}
+
+/*
+ * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
+ * One SYN_RECV socket costs about 80bytes on a 32bit machine.
+ * It would be better to replace it with a global counter for all sockets
+ * but then some measure against one socket starving all other sockets
+ * would be needed.
+ *
+ * It was 128 by default. Experiments with real servers show, that
+ * it is absolutely not enough even at 100conn/sec. 256 cures most
+ * of problems. This value is adjusted to 128 for very small machines
+ * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
+ * Further increasing requires to change hash table size.
+ */
+int sysctl_max_syn_backlog = 256;
+
+struct or_calltable or_ipv4 = {
+ .family = PF_INET,
+ .rtx_syn_ack = tcp_v4_send_synack,
+ .send_ack = tcp_v4_or_send_ack,
+ .destructor = tcp_v4_or_free,
+ .send_reset = tcp_v4_send_reset,
+};
+
+int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_options_received tmp_opt;
+ struct open_request *req;
+ __u32 saddr = skb->nh.iph->saddr;
+ __u32 daddr = skb->nh.iph->daddr;
+ __u32 isn = TCP_SKB_CB(skb)->when;
+ struct dst_entry *dst = NULL;
+#ifdef CONFIG_SYN_COOKIES
+ int want_cookie = 0;
+#else
+#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
+#endif
+
+ /* Never answer to SYNs send to broadcast or multicast */
+ if (((struct rtable *)skb->dst)->rt_flags &
+ (RTCF_BROADCAST | RTCF_MULTICAST))
+ goto drop;
+
+ /* TW buckets are converted to open requests without
+ * limitations, they conserve resources and peer is
+ * evidently real one.
+ */
+ if (tcp_synq_is_full(sk) && !isn) {
+#ifdef CONFIG_SYN_COOKIES
+ if (sysctl_tcp_syncookies) {
+ want_cookie = 1;
+ } else
+#endif
+ goto drop;
+ }
+
+ /* Accept backlog is full. If we have already queued enough
+ * of warm entries in syn queue, drop request. It is better than
+ * clogging syn queue with openreqs with exponentially increasing
+ * timeout.
+ */
+ if (sk_acceptq_is_full(sk) && tcp_synq_young(sk) > 1)
+ goto drop;
+
+ req = tcp_openreq_alloc();
+ if (!req)
+ goto drop;
+
+ tcp_clear_options(&tmp_opt);
+ tmp_opt.mss_clamp = 536;
+ tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
+
+ tcp_parse_options(skb, &tmp_opt, 0);
+
+ if (want_cookie) {
+ tcp_clear_options(&tmp_opt);
+ tmp_opt.saw_tstamp = 0;
+ }
+
+ if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
+ /* Some OSes (unknown ones, but I see them on web server, which
+ * contains information interesting only for windows'
+ * users) do not send their stamp in SYN. It is easy case.
+ * We simply do not advertise TS support.
+ */
+ tmp_opt.saw_tstamp = 0;
+ tmp_opt.tstamp_ok = 0;
+ }
+ tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
+
+ tcp_openreq_init(req, &tmp_opt, skb);
+
+ req->af.v4_req.loc_addr = daddr;
+ req->af.v4_req.rmt_addr = saddr;
+ req->af.v4_req.opt = tcp_v4_save_options(sk, skb);
+ req->class = &or_ipv4;
+ if (!want_cookie)
+ TCP_ECN_create_request(req, skb->h.th);
+
+ if (want_cookie) {
+#ifdef CONFIG_SYN_COOKIES
+ syn_flood_warning(skb);
+#endif
+ isn = cookie_v4_init_sequence(sk, skb, &req->mss);
+ } else if (!isn) {
+ struct inet_peer *peer = NULL;
+
+ /* VJ's idea. We save last timestamp seen
+ * from the destination in peer table, when entering
+ * state TIME-WAIT, and check against it before
+ * accepting new connection request.
+ *
+ * If "isn" is not zero, this request hit alive
+ * timewait bucket, so that all the necessary checks
+ * are made in the function processing timewait state.
+ */
+ if (tmp_opt.saw_tstamp &&
+ sysctl_tcp_tw_recycle &&
+ (dst = tcp_v4_route_req(sk, req)) != NULL &&
+ (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
+ peer->v4daddr == saddr) {
+ if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
+ (s32)(peer->tcp_ts - req->ts_recent) >
+ TCP_PAWS_WINDOW) {
+ NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
+ dst_release(dst);
+ goto drop_and_free;
+ }
+ }
+ /* Kill the following clause, if you dislike this way. */
+ else if (!sysctl_tcp_syncookies &&
+ (sysctl_max_syn_backlog - tcp_synq_len(sk) <
+ (sysctl_max_syn_backlog >> 2)) &&
+ (!peer || !peer->tcp_ts_stamp) &&
+ (!dst || !dst_metric(dst, RTAX_RTT))) {
+ /* Without syncookies last quarter of
+ * backlog is filled with destinations,
+ * proven to be alive.
+ * It means that we continue to communicate
+ * to destinations, already remembered
+ * to the moment of synflood.
+ */
+ NETDEBUG(if (net_ratelimit()) \
+ printk(KERN_DEBUG "TCP: drop open "
+ "request from %u.%u."
+ "%u.%u/%u\n", \
+ NIPQUAD(saddr),
+ ntohs(skb->h.th->source)));
+ dst_release(dst);
+ goto drop_and_free;
+ }
+
+ isn = tcp_v4_init_sequence(sk, skb);
+ }
+ req->snt_isn = isn;
+
+ if (tcp_v4_send_synack(sk, req, dst))
+ goto drop_and_free;
+
+ if (want_cookie) {
+ tcp_openreq_free(req);
+ } else {
+ tcp_v4_synq_add(sk, req);
+ }
+ return 0;
+
+drop_and_free:
+ tcp_openreq_free(req);
+drop:
+ TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
+ return 0;
+}
+
+
+/*
+ * The three way handshake has completed - we got a valid synack -
+ * now create the new socket.
+ */
+struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+ struct open_request *req,
+ struct dst_entry *dst)
+{
+ struct inet_sock *newinet;
+ struct tcp_sock *newtp;
+ struct sock *newsk;
+
+ if (sk_acceptq_is_full(sk))
+ goto exit_overflow;
+
+ if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
+ goto exit;
+
+ newsk = tcp_create_openreq_child(sk, req, skb);
+ if (!newsk)
+ goto exit;
+
+ newsk->sk_dst_cache = dst;
+ tcp_v4_setup_caps(newsk, dst);
+
+ newtp = tcp_sk(newsk);
+ newinet = inet_sk(newsk);
+ newinet->daddr = req->af.v4_req.rmt_addr;
+ newinet->rcv_saddr = req->af.v4_req.loc_addr;
+ newinet->saddr = req->af.v4_req.loc_addr;
+ newinet->opt = req->af.v4_req.opt;
+ req->af.v4_req.opt = NULL;
+ newinet->mc_index = tcp_v4_iif(skb);
+ newinet->mc_ttl = skb->nh.iph->ttl;
+ newtp->ext_header_len = 0;
+ if (newinet->opt)
+ newtp->ext_header_len = newinet->opt->optlen;
+ newinet->id = newtp->write_seq ^ jiffies;
+
+ tcp_sync_mss(newsk, dst_mtu(dst));
+ newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
+ tcp_initialize_rcv_mss(newsk);
+
+ __tcp_v4_hash(newsk, 0);
+ __tcp_inherit_port(sk, newsk);
+
+ return newsk;
+
+exit_overflow:
+ NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
+exit:
+ NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
+ dst_release(dst);
+ return NULL;
+}
+
+static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcphdr *th = skb->h.th;
+ struct iphdr *iph = skb->nh.iph;
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sock *nsk;
+ struct open_request **prev;
+ /* Find possible connection requests. */
+ struct open_request *req = tcp_v4_search_req(tp, &prev, th->source,
+ iph->saddr, iph->daddr);
+ 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));
+
+ if (nsk) {
+ if (nsk->sk_state != TCP_TIME_WAIT) {
+ bh_lock_sock(nsk);
+ return nsk;
+ }
+ tcp_tw_put((struct tcp_tw_bucket *)nsk);
+ return NULL;
+ }
+
+#ifdef CONFIG_SYN_COOKIES
+ if (!th->rst && !th->syn && th->ack)
+ sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
+#endif
+ return sk;
+}
+
+static int tcp_v4_checksum_init(struct sk_buff *skb)
+{
+ if (skb->ip_summed == CHECKSUM_HW) {
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
+ skb->nh.iph->daddr, skb->csum))
+ return 0;
+
+ NETDEBUG(if (net_ratelimit())
+ printk(KERN_DEBUG "hw tcp v4 csum failed\n"));
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+ if (skb->len <= 76) {
+ if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
+ skb->nh.iph->daddr,
+ skb_checksum(skb, 0, skb->len, 0)))
+ return -1;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ } else {
+ skb->csum = ~tcp_v4_check(skb->h.th, skb->len,
+ skb->nh.iph->saddr,
+ skb->nh.iph->daddr, 0);
+ }
+ return 0;
+}
+
+
+/* The socket must have it's spinlock held when we get
+ * here.
+ *
+ * We have a potential double-lock case here, so even when
+ * doing backlog processing we use the BH locking scheme.
+ * This is because we cannot sleep with the original spinlock
+ * held.
+ */
+int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+ if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
+ TCP_CHECK_TIMER(sk);
+ if (tcp_rcv_established(sk, skb, skb->h.th, skb->len))
+ goto reset;
+ TCP_CHECK_TIMER(sk);
+ return 0;
+ }
+
+ if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb))
+ goto csum_err;
+
+ if (sk->sk_state == TCP_LISTEN) {
+ struct sock *nsk = tcp_v4_hnd_req(sk, skb);
+ if (!nsk)
+ goto discard;
+
+ if (nsk != sk) {
+ if (tcp_child_process(sk, nsk, skb))
+ goto reset;
+ return 0;
+ }
+ }
+
+ TCP_CHECK_TIMER(sk);
+ if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len))
+ goto reset;
+ TCP_CHECK_TIMER(sk);
+ return 0;
+
+reset:
+ tcp_v4_send_reset(skb);
+discard:
+ kfree_skb(skb);
+ /* Be careful here. If this function gets more complicated and
+ * gcc suffers from register pressure on the x86, sk (in %ebx)
+ * might be destroyed here. This current version compiles correctly,
+ * but you have been warned.
+ */
+ return 0;
+
+csum_err:
+ TCP_INC_STATS_BH(TCP_MIB_INERRS);
+ goto discard;
+}
+
+/*
+ * From tcp_input.c
+ */
+
+int tcp_v4_rcv(struct sk_buff *skb)
+{
+ struct tcphdr *th;
+ struct sock *sk;
+ int ret;
+
+ if (skb->pkt_type != PACKET_HOST)
+ goto discard_it;
+
+ /* Count it even if it's bad */
+ TCP_INC_STATS_BH(TCP_MIB_INSEGS);
+
+ if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
+ goto discard_it;
+
+ th = skb->h.th;
+
+ if (th->doff < sizeof(struct tcphdr) / 4)
+ goto bad_packet;
+ if (!pskb_may_pull(skb, th->doff * 4))
+ goto discard_it;
+
+ /* An explanation is required here, I think.
+ * Packet length and doff are validated by header prediction,
+ * provided case of th->doff==0 is elimineted.
+ * So, we defer the checks. */
+ if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
+ tcp_v4_checksum_init(skb) < 0))
+ goto bad_packet;
+
+ th = skb->h.th;
+ TCP_SKB_CB(skb)->seq = ntohl(th->seq);
+ TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
+ skb->len - th->doff * 4);
+ TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
+ TCP_SKB_CB(skb)->when = 0;
+ 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));
+
+ if (!sk)
+ goto no_tcp_socket;
+
+process:
+ if (sk->sk_state == TCP_TIME_WAIT)
+ goto do_time_wait;
+
+ if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+ goto discard_and_relse;
+
+ if (sk_filter(sk, skb, 0))
+ goto discard_and_relse;
+
+ skb->dev = NULL;
+
+ bh_lock_sock(sk);
+ ret = 0;
+ if (!sock_owned_by_user(sk)) {
+ if (!tcp_prequeue(sk, skb))
+ ret = tcp_v4_do_rcv(sk, skb);
+ } else
+ sk_add_backlog(sk, skb);
+ bh_unlock_sock(sk);
+
+ sock_put(sk);
+
+ return ret;
+
+no_tcp_socket:
+ if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+ goto discard_it;
+
+ if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
+bad_packet:
+ TCP_INC_STATS_BH(TCP_MIB_INERRS);
+ } else {
+ tcp_v4_send_reset(skb);
+ }
+
+discard_it:
+ /* Discard frame. */
+ kfree_skb(skb);
+ return 0;
+
+discard_and_relse:
+ sock_put(sk);
+ goto discard_it;
+
+do_time_wait:
+ if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+ tcp_tw_put((struct tcp_tw_bucket *) 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);
+ goto discard_it;
+ }
+ switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
+ skb, th, skb->len)) {
+ case TCP_TW_SYN: {
+ struct sock *sk2 = tcp_v4_lookup_listener(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);
+ sk = sk2;
+ goto process;
+ }
+ /* Fall through to ACK */
+ }
+ case TCP_TW_ACK:
+ tcp_v4_timewait_ack(sk, skb);
+ break;
+ case TCP_TW_RST:
+ goto no_tcp_socket;
+ case TCP_TW_SUCCESS:;
+ }
+ goto discard_it;
+}
+
+/* With per-bucket locks this operation is not-atomic, so that
+ * this version is not worse.
+ */
+static void __tcp_v4_rehash(struct sock *sk)
+{
+ sk->sk_prot->unhash(sk);
+ sk->sk_prot->hash(sk);
+}
+
+static int tcp_v4_reselect_saddr(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ int err;
+ struct rtable *rt;
+ __u32 old_saddr = inet->saddr;
+ __u32 new_saddr;
+ __u32 daddr = inet->daddr;
+
+ if (inet->opt && inet->opt->srr)
+ daddr = inet->opt->faddr;
+
+ /* Query new route. */
+ err = ip_route_connect(&rt, daddr, 0,
+ RT_CONN_FLAGS(sk),
+ sk->sk_bound_dev_if,
+ IPPROTO_TCP,
+ inet->sport, inet->dport, sk);
+ if (err)
+ return err;
+
+ __sk_dst_set(sk, &rt->u.dst);
+ tcp_v4_setup_caps(sk, &rt->u.dst);
+
+ new_saddr = rt->rt_src;
+
+ if (new_saddr == old_saddr)
+ return 0;
+
+ if (sysctl_ip_dynaddr > 1) {
+ printk(KERN_INFO "tcp_v4_rebuild_header(): shifting inet->"
+ "saddr from %d.%d.%d.%d to %d.%d.%d.%d\n",
+ NIPQUAD(old_saddr),
+ NIPQUAD(new_saddr));
+ }
+
+ inet->saddr = new_saddr;
+ inet->rcv_saddr = new_saddr;
+
+ /* XXX The only one ugly spot where we need to
+ * XXX really change the sockets identity after
+ * XXX it has entered the hashes. -DaveM
+ *
+ * Besides that, it does not check for connection
+ * uniqueness. Wait for troubles.
+ */
+ __tcp_v4_rehash(sk);
+ return 0;
+}
+
+int tcp_v4_rebuild_header(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
+ u32 daddr;
+ int err;
+
+ /* Route is OK, nothing to do. */
+ if (rt)
+ return 0;
+
+ /* Reroute. */
+ daddr = inet->daddr;
+ if (inet->opt && inet->opt->srr)
+ daddr = inet->opt->faddr;
+
+ {
+ struct flowi fl = { .oif = sk->sk_bound_dev_if,
+ .nl_u = { .ip4_u =
+ { .daddr = daddr,
+ .saddr = inet->saddr,
+ .tos = RT_CONN_FLAGS(sk) } },
+ .proto = IPPROTO_TCP,
+ .uli_u = { .ports =
+ { .sport = inet->sport,
+ .dport = inet->dport } } };
+
+ err = ip_route_output_flow(&rt, &fl, sk, 0);
+ }
+ if (!err) {
+ __sk_dst_set(sk, &rt->u.dst);
+ tcp_v4_setup_caps(sk, &rt->u.dst);
+ return 0;
+ }
+
+ /* Routing failed... */
+ sk->sk_route_caps = 0;
+
+ if (!sysctl_ip_dynaddr ||
+ sk->sk_state != TCP_SYN_SENT ||
+ (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
+ (err = tcp_v4_reselect_saddr(sk)) != 0)
+ sk->sk_err_soft = -err;
+
+ return err;
+}
+
+static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
+{
+ struct sockaddr_in *sin = (struct sockaddr_in *) uaddr;
+ struct inet_sock *inet = inet_sk(sk);
+
+ sin->sin_family = AF_INET;
+ sin->sin_addr.s_addr = inet->daddr;
+ sin->sin_port = inet->dport;
+}
+
+/* VJ's idea. Save last timestamp seen from this destination
+ * and hold it at least for normal timewait interval to use for duplicate
+ * segment detection in subsequent connections, before they enter synchronized
+ * state.
+ */
+
+int tcp_v4_remember_stamp(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
+ struct inet_peer *peer = NULL;
+ int release_it = 0;
+
+ if (!rt || rt->rt_dst != inet->daddr) {
+ peer = inet_getpeer(inet->daddr, 1);
+ release_it = 1;
+ } else {
+ if (!rt->peer)
+ rt_bind_peer(rt, 1);
+ peer = rt->peer;
+ }
+
+ if (peer) {
+ if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
+ (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
+ peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
+ peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
+ peer->tcp_ts = tp->rx_opt.ts_recent;
+ }
+ if (release_it)
+ inet_putpeer(peer);
+ return 1;
+ }
+
+ return 0;
+}
+
+int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw)
+{
+ struct inet_peer *peer = NULL;
+
+ peer = inet_getpeer(tw->tw_daddr, 1);
+
+ if (peer) {
+ if ((s32)(peer->tcp_ts - tw->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;
+ }
+ inet_putpeer(peer);
+ return 1;
+ }
+
+ return 0;
+}
+
+struct tcp_func ipv4_specific = {
+ .queue_xmit = ip_queue_xmit,
+ .send_check = tcp_v4_send_check,
+ .rebuild_header = tcp_v4_rebuild_header,
+ .conn_request = tcp_v4_conn_request,
+ .syn_recv_sock = tcp_v4_syn_recv_sock,
+ .remember_stamp = tcp_v4_remember_stamp,
+ .net_header_len = sizeof(struct iphdr),
+ .setsockopt = ip_setsockopt,
+ .getsockopt = ip_getsockopt,
+ .addr2sockaddr = v4_addr2sockaddr,
+ .sockaddr_len = sizeof(struct sockaddr_in),
+};
+
+/* NOTE: A lot of things set to zero explicitly by call to
+ * sk_alloc() so need not be done here.
+ */
+static int tcp_v4_init_sock(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ skb_queue_head_init(&tp->out_of_order_queue);
+ tcp_init_xmit_timers(sk);
+ tcp_prequeue_init(tp);
+
+ tp->rto = TCP_TIMEOUT_INIT;
+ tp->mdev = TCP_TIMEOUT_INIT;
+
+ /* So many TCP implementations out there (incorrectly) count the
+ * initial SYN frame in their delayed-ACK and congestion control
+ * algorithms that we must have the following bandaid to talk
+ * efficiently to them. -DaveM
+ */
+ tp->snd_cwnd = 2;
+
+ /* See draft-stevens-tcpca-spec-01 for discussion of the
+ * initialization of these values.
+ */
+ tp->snd_ssthresh = 0x7fffffff; /* Infinity */
+ tp->snd_cwnd_clamp = ~0;
+ tp->mss_cache_std = tp->mss_cache = 536;
+
+ tp->reordering = sysctl_tcp_reordering;
+
+ sk->sk_state = TCP_CLOSE;
+
+ sk->sk_write_space = sk_stream_write_space;
+ sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
+
+ tp->af_specific = &ipv4_specific;
+
+ sk->sk_sndbuf = sysctl_tcp_wmem[1];
+ sk->sk_rcvbuf = sysctl_tcp_rmem[1];
+
+ atomic_inc(&tcp_sockets_allocated);
+
+ return 0;
+}
+
+int tcp_v4_destroy_sock(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ tcp_clear_xmit_timers(sk);
+
+ /* Cleanup up the write buffer. */
+ sk_stream_writequeue_purge(sk);
+
+ /* Cleans up our, hopefully empty, out_of_order_queue. */
+ __skb_queue_purge(&tp->out_of_order_queue);
+
+ /* Clean prequeue, it must be empty really */
+ __skb_queue_purge(&tp->ucopy.prequeue);
+
+ /* Clean up a referenced TCP bind bucket. */
+ if (tp->bind_hash)
+ tcp_put_port(sk);
+
+ /*
+ * If sendmsg cached page exists, toss it.
+ */
+ if (sk->sk_sndmsg_page) {
+ __free_page(sk->sk_sndmsg_page);
+ sk->sk_sndmsg_page = NULL;
+ }
+
+ atomic_dec(&tcp_sockets_allocated);
+
+ return 0;
+}
+
+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)
+{
+ return hlist_empty(head) ? NULL :
+ list_entry(head->first, struct tcp_tw_bucket, tw_node);
+}
+
+static inline struct tcp_tw_bucket *tw_next(struct tcp_tw_bucket *tw)
+{
+ return tw->tw_node.next ?
+ hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
+}
+
+static void *listening_get_next(struct seq_file *seq, void *cur)
+{
+ struct tcp_sock *tp;
+ struct hlist_node *node;
+ struct sock *sk = cur;
+ struct tcp_iter_state* st = seq->private;
+
+ if (!sk) {
+ st->bucket = 0;
+ sk = sk_head(&tcp_listening_hash[0]);
+ goto get_sk;
+ }
+
+ ++st->num;
+
+ if (st->state == TCP_SEQ_STATE_OPENREQ) {
+ struct open_request *req = cur;
+
+ tp = tcp_sk(st->syn_wait_sk);
+ req = req->dl_next;
+ while (1) {
+ while (req) {
+ if (req->class->family == st->family) {
+ cur = req;
+ goto out;
+ }
+ req = req->dl_next;
+ }
+ if (++st->sbucket >= TCP_SYNQ_HSIZE)
+ break;
+get_req:
+ req = tp->listen_opt->syn_table[st->sbucket];
+ }
+ sk = sk_next(st->syn_wait_sk);
+ st->state = TCP_SEQ_STATE_LISTENING;
+ read_unlock_bh(&tp->syn_wait_lock);
+ } else {
+ tp = tcp_sk(sk);
+ read_lock_bh(&tp->syn_wait_lock);
+ if (tp->listen_opt && tp->listen_opt->qlen)
+ goto start_req;
+ read_unlock_bh(&tp->syn_wait_lock);
+ sk = sk_next(sk);
+ }
+get_sk:
+ sk_for_each_from(sk, node) {
+ if (sk->sk_family == st->family) {
+ cur = sk;
+ goto out;
+ }
+ tp = tcp_sk(sk);
+ read_lock_bh(&tp->syn_wait_lock);
+ if (tp->listen_opt && tp->listen_opt->qlen) {
+start_req:
+ st->uid = sock_i_uid(sk);
+ st->syn_wait_sk = sk;
+ st->state = TCP_SEQ_STATE_OPENREQ;
+ st->sbucket = 0;
+ goto get_req;
+ }
+ read_unlock_bh(&tp->syn_wait_lock);
+ }
+ if (++st->bucket < TCP_LHTABLE_SIZE) {
+ sk = sk_head(&tcp_listening_hash[st->bucket]);
+ goto get_sk;
+ }
+ cur = NULL;
+out:
+ return cur;
+}
+
+static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
+{
+ void *rc = listening_get_next(seq, NULL);
+
+ while (rc && *pos) {
+ rc = listening_get_next(seq, rc);
+ --*pos;
+ }
+ return rc;
+}
+
+static void *established_get_first(struct seq_file *seq)
+{
+ struct tcp_iter_state* st = seq->private;
+ void *rc = NULL;
+
+ for (st->bucket = 0; st->bucket < tcp_ehash_size; ++st->bucket) {
+ struct sock *sk;
+ struct hlist_node *node;
+ struct tcp_tw_bucket *tw;
+
+ /* We can reschedule _before_ having picked the target: */
+ cond_resched_softirq();
+
+ read_lock(&tcp_ehash[st->bucket].lock);
+ sk_for_each(sk, node, &tcp_ehash[st->bucket].chain) {
+ if (sk->sk_family != st->family) {
+ continue;
+ }
+ rc = sk;
+ goto out;
+ }
+ st->state = TCP_SEQ_STATE_TIME_WAIT;
+ tw_for_each(tw, node,
+ &tcp_ehash[st->bucket + tcp_ehash_size].chain) {
+ if (tw->tw_family != st->family) {
+ continue;
+ }
+ rc = tw;
+ goto out;
+ }
+ read_unlock(&tcp_ehash[st->bucket].lock);
+ st->state = TCP_SEQ_STATE_ESTABLISHED;
+ }
+out:
+ return rc;
+}
+
+static void *established_get_next(struct seq_file *seq, void *cur)
+{
+ struct sock *sk = cur;
+ struct tcp_tw_bucket *tw;
+ struct hlist_node *node;
+ struct tcp_iter_state* st = seq->private;
+
+ ++st->num;
+
+ if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
+ tw = cur;
+ tw = tw_next(tw);
+get_tw:
+ while (tw && tw->tw_family != st->family) {
+ tw = tw_next(tw);
+ }
+ if (tw) {
+ cur = tw;
+ goto out;
+ }
+ read_unlock(&tcp_ehash[st->bucket].lock);
+ st->state = TCP_SEQ_STATE_ESTABLISHED;
+
+ /* We can reschedule between buckets: */
+ cond_resched_softirq();
+
+ if (++st->bucket < tcp_ehash_size) {
+ read_lock(&tcp_ehash[st->bucket].lock);
+ sk = sk_head(&tcp_ehash[st->bucket].chain);
+ } else {
+ cur = NULL;
+ goto out;
+ }
+ } else
+ sk = sk_next(sk);
+
+ sk_for_each_from(sk, node) {
+ if (sk->sk_family == st->family)
+ goto found;
+ }
+
+ st->state = TCP_SEQ_STATE_TIME_WAIT;
+ tw = tw_head(&tcp_ehash[st->bucket + tcp_ehash_size].chain);
+ goto get_tw;
+found:
+ cur = sk;
+out:
+ return cur;
+}
+
+static void *established_get_idx(struct seq_file *seq, loff_t pos)
+{
+ void *rc = established_get_first(seq);
+
+ while (rc && pos) {
+ rc = established_get_next(seq, rc);
+ --pos;
+ }
+ return rc;
+}
+
+static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
+{
+ void *rc;
+ struct tcp_iter_state* st = seq->private;
+
+ tcp_listen_lock();
+ st->state = TCP_SEQ_STATE_LISTENING;
+ rc = listening_get_idx(seq, &pos);
+
+ if (!rc) {
+ tcp_listen_unlock();
+ local_bh_disable();
+ st->state = TCP_SEQ_STATE_ESTABLISHED;
+ rc = established_get_idx(seq, pos);
+ }
+
+ return rc;
+}
+
+static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct tcp_iter_state* st = seq->private;
+ st->state = TCP_SEQ_STATE_LISTENING;
+ st->num = 0;
+ return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ void *rc = NULL;
+ struct tcp_iter_state* st;
+
+ if (v == SEQ_START_TOKEN) {
+ rc = tcp_get_idx(seq, 0);
+ goto out;
+ }
+ st = seq->private;
+
+ switch (st->state) {
+ case TCP_SEQ_STATE_OPENREQ:
+ case TCP_SEQ_STATE_LISTENING:
+ rc = listening_get_next(seq, v);
+ if (!rc) {
+ tcp_listen_unlock();
+ local_bh_disable();
+ st->state = TCP_SEQ_STATE_ESTABLISHED;
+ rc = established_get_first(seq);
+ }
+ break;
+ case TCP_SEQ_STATE_ESTABLISHED:
+ case TCP_SEQ_STATE_TIME_WAIT:
+ rc = established_get_next(seq, v);
+ break;
+ }
+out:
+ ++*pos;
+ return rc;
+}
+
+static void tcp_seq_stop(struct seq_file *seq, void *v)
+{
+ struct tcp_iter_state* st = seq->private;
+
+ switch (st->state) {
+ case TCP_SEQ_STATE_OPENREQ:
+ if (v) {
+ struct tcp_sock *tp = tcp_sk(st->syn_wait_sk);
+ read_unlock_bh(&tp->syn_wait_lock);
+ }
+ case TCP_SEQ_STATE_LISTENING:
+ if (v != SEQ_START_TOKEN)
+ tcp_listen_unlock();
+ break;
+ case TCP_SEQ_STATE_TIME_WAIT:
+ case TCP_SEQ_STATE_ESTABLISHED:
+ if (v)
+ read_unlock(&tcp_ehash[st->bucket].lock);
+ local_bh_enable();
+ break;
+ }
+}
+
+static int tcp_seq_open(struct inode *inode, struct file *file)
+{
+ struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
+ struct seq_file *seq;
+ struct tcp_iter_state *s;
+ int rc;
+
+ if (unlikely(afinfo == NULL))
+ return -EINVAL;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+ memset(s, 0, sizeof(*s));
+ s->family = afinfo->family;
+ s->seq_ops.start = tcp_seq_start;
+ s->seq_ops.next = tcp_seq_next;
+ s->seq_ops.show = afinfo->seq_show;
+ s->seq_ops.stop = tcp_seq_stop;
+
+ rc = seq_open(file, &s->seq_ops);
+ if (rc)
+ goto out_kfree;
+ seq = file->private_data;
+ seq->private = s;
+out:
+ return rc;
+out_kfree:
+ kfree(s);
+ goto out;
+}
+
+int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
+{
+ int rc = 0;
+ struct proc_dir_entry *p;
+
+ if (!afinfo)
+ return -EINVAL;
+ afinfo->seq_fops->owner = afinfo->owner;
+ afinfo->seq_fops->open = tcp_seq_open;
+ afinfo->seq_fops->read = seq_read;
+ afinfo->seq_fops->llseek = seq_lseek;
+ afinfo->seq_fops->release = seq_release_private;
+
+ p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
+ if (p)
+ p->data = afinfo;
+ else
+ rc = -ENOMEM;
+ return rc;
+}
+
+void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
+{
+ if (!afinfo)
+ return;
+ proc_net_remove(afinfo->name);
+ memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
+}
+
+static void get_openreq4(struct sock *sk, struct open_request *req,
+ char *tmpbuf, int i, int uid)
+{
+ int ttd = req->expires - jiffies;
+
+ sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
+ i,
+ req->af.v4_req.loc_addr,
+ ntohs(inet_sk(sk)->sport),
+ req->af.v4_req.rmt_addr,
+ ntohs(req->rmt_port),
+ TCP_SYN_RECV,
+ 0, 0, /* could print option size, but that is af dependent. */
+ 1, /* timers active (only the expire timer) */
+ jiffies_to_clock_t(ttd),
+ req->retrans,
+ uid,
+ 0, /* non standard timer */
+ 0, /* open_requests have no inode */
+ atomic_read(&sk->sk_refcnt),
+ req);
+}
+
+static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
+{
+ int timer_active;
+ unsigned long timer_expires;
+ struct tcp_sock *tp = tcp_sk(sp);
+ struct inet_sock *inet = inet_sk(sp);
+ unsigned int dest = inet->daddr;
+ unsigned int src = inet->rcv_saddr;
+ __u16 destp = ntohs(inet->dport);
+ __u16 srcp = ntohs(inet->sport);
+
+ if (tp->pending == TCP_TIME_RETRANS) {
+ timer_active = 1;
+ timer_expires = tp->timeout;
+ } else if (tp->pending == TCP_TIME_PROBE0) {
+ timer_active = 4;
+ timer_expires = tp->timeout;
+ } else if (timer_pending(&sp->sk_timer)) {
+ timer_active = 2;
+ timer_expires = sp->sk_timer.expires;
+ } else {
+ timer_active = 0;
+ timer_expires = jiffies;
+ }
+
+ sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
+ "%08X %5d %8d %lu %d %p %u %u %u %u %d",
+ i, src, srcp, dest, destp, sp->sk_state,
+ tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq,
+ timer_active,
+ jiffies_to_clock_t(timer_expires - jiffies),
+ tp->retransmits,
+ sock_i_uid(sp),
+ tp->probes_out,
+ sock_i_ino(sp),
+ atomic_read(&sp->sk_refcnt), sp,
+ tp->rto, tp->ack.ato, (tp->ack.quick << 1) | tp->ack.pingpong,
+ tp->snd_cwnd,
+ tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
+}
+
+static void get_timewait4_sock(struct tcp_tw_bucket *tw, char *tmpbuf, int i)
+{
+ unsigned int dest, src;
+ __u16 destp, srcp;
+ int ttd = tw->tw_ttd - jiffies;
+
+ if (ttd < 0)
+ ttd = 0;
+
+ dest = tw->tw_daddr;
+ src = tw->tw_rcv_saddr;
+ destp = ntohs(tw->tw_dport);
+ srcp = ntohs(tw->tw_sport);
+
+ sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
+ i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
+ 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
+ atomic_read(&tw->tw_refcnt), tw);
+}
+
+#define TMPSZ 150
+
+static int tcp4_seq_show(struct seq_file *seq, void *v)
+{
+ struct tcp_iter_state* st;
+ char tmpbuf[TMPSZ + 1];
+
+ if (v == SEQ_START_TOKEN) {
+ seq_printf(seq, "%-*s\n", TMPSZ - 1,
+ " sl local_address rem_address st tx_queue "
+ "rx_queue tr tm->when retrnsmt uid timeout "
+ "inode");
+ goto out;
+ }
+ st = seq->private;
+
+ switch (st->state) {
+ case TCP_SEQ_STATE_LISTENING:
+ case TCP_SEQ_STATE_ESTABLISHED:
+ get_tcp4_sock(v, tmpbuf, st->num);
+ break;
+ case TCP_SEQ_STATE_OPENREQ:
+ get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
+ break;
+ case TCP_SEQ_STATE_TIME_WAIT:
+ get_timewait4_sock(v, tmpbuf, st->num);
+ break;
+ }
+ seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
+out:
+ return 0;
+}
+
+static struct file_operations tcp4_seq_fops;
+static struct tcp_seq_afinfo tcp4_seq_afinfo = {
+ .owner = THIS_MODULE,
+ .name = "tcp",
+ .family = AF_INET,
+ .seq_show = tcp4_seq_show,
+ .seq_fops = &tcp4_seq_fops,
+};
+
+int __init tcp4_proc_init(void)
+{
+ return tcp_proc_register(&tcp4_seq_afinfo);
+}
+
+void tcp4_proc_exit(void)
+{
+ tcp_proc_unregister(&tcp4_seq_afinfo);
+}
+#endif /* CONFIG_PROC_FS */
+
+struct proto tcp_prot = {
+ .name = "TCP",
+ .owner = THIS_MODULE,
+ .close = tcp_close,
+ .connect = tcp_v4_connect,
+ .disconnect = tcp_disconnect,
+ .accept = tcp_accept,
+ .ioctl = tcp_ioctl,
+ .init = tcp_v4_init_sock,
+ .destroy = tcp_v4_destroy_sock,
+ .shutdown = tcp_shutdown,
+ .setsockopt = tcp_setsockopt,
+ .getsockopt = tcp_getsockopt,
+ .sendmsg = tcp_sendmsg,
+ .recvmsg = tcp_recvmsg,
+ .backlog_rcv = tcp_v4_do_rcv,
+ .hash = tcp_v4_hash,
+ .unhash = tcp_unhash,
+ .get_port = tcp_v4_get_port,
+ .enter_memory_pressure = tcp_enter_memory_pressure,
+ .sockets_allocated = &tcp_sockets_allocated,
+ .memory_allocated = &tcp_memory_allocated,
+ .memory_pressure = &tcp_memory_pressure,
+ .sysctl_mem = sysctl_tcp_mem,
+ .sysctl_wmem = sysctl_tcp_wmem,
+ .sysctl_rmem = sysctl_tcp_rmem,
+ .max_header = MAX_TCP_HEADER,
+ .obj_size = sizeof(struct tcp_sock),
+};
+
+
+
+void __init tcp_v4_init(struct net_proto_family *ops)
+{
+ int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket);
+ if (err < 0)
+ panic("Failed to create the TCP control socket.\n");
+ tcp_socket->sk->sk_allocation = GFP_ATOMIC;
+ inet_sk(tcp_socket->sk)->uc_ttl = -1;
+
+ /* Unhash it so that IP input processing does not even
+ * see it, we do not wish this socket to see incoming
+ * packets.
+ */
+ tcp_socket->sk->sk_prot->unhash(tcp_socket->sk);
+}
+
+EXPORT_SYMBOL(ipv4_specific);
+EXPORT_SYMBOL(tcp_bind_hash);
+EXPORT_SYMBOL(tcp_bucket_create);
+EXPORT_SYMBOL(tcp_hashinfo);
+EXPORT_SYMBOL(tcp_inherit_port);
+EXPORT_SYMBOL(tcp_listen_wlock);
+EXPORT_SYMBOL(tcp_port_rover);
+EXPORT_SYMBOL(tcp_prot);
+EXPORT_SYMBOL(tcp_put_port);
+EXPORT_SYMBOL(tcp_unhash);
+EXPORT_SYMBOL(tcp_v4_conn_request);
+EXPORT_SYMBOL(tcp_v4_connect);
+EXPORT_SYMBOL(tcp_v4_do_rcv);
+EXPORT_SYMBOL(tcp_v4_rebuild_header);
+EXPORT_SYMBOL(tcp_v4_remember_stamp);
+EXPORT_SYMBOL(tcp_v4_send_check);
+EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
+
+#ifdef CONFIG_PROC_FS
+EXPORT_SYMBOL(tcp_proc_register);
+EXPORT_SYMBOL(tcp_proc_unregister);
+#endif
+EXPORT_SYMBOL(sysctl_local_port_range);
+EXPORT_SYMBOL(sysctl_max_syn_backlog);
+EXPORT_SYMBOL(sysctl_tcp_low_latency);
+EXPORT_SYMBOL(sysctl_tcp_tw_reuse);
+