diff options
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 2663 |
1 files changed, 2663 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c new file mode 100644 index 000000000000..3ac6659869c4 --- /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); + |