linux/net/ipv4/inet_connection_sock.c
Al Viro dd0fc66fb3 [PATCH] gfp flags annotations - part 1
- added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00

642 lines
17 KiB
C

/*
* 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.
*
* Support for INET connection oriented protocols.
*
* Authors: See the TCP sources
*
* 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.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/jhash.h>
#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp_states.h>
#include <net/xfrm.h>
#ifdef INET_CSK_DEBUG
const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
EXPORT_SYMBOL(inet_csk_timer_bug_msg);
#endif
/*
* 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 };
static inline int inet_csk_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb)
{
const u32 sk_rcv_saddr = inet_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 &&
!inet_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 = inet_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.
*/
int inet_csk_get_port(struct inet_hashinfo *hashinfo,
struct sock *sk, unsigned short snum)
{
struct inet_bind_hashbucket *head;
struct hlist_node *node;
struct inet_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(&hashinfo->portalloc_lock);
if (hashinfo->port_rover < low)
rover = low;
else
rover = hashinfo->port_rover;
do {
rover++;
if (rover > high)
rover = low;
head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
spin_lock(&head->lock);
inet_bind_bucket_for_each(tb, node, &head->chain)
if (tb->port == rover)
goto next;
break;
next:
spin_unlock(&head->lock);
} while (--remaining > 0);
hashinfo->port_rover = rover;
spin_unlock(&hashinfo->portalloc_lock);
/* Exhausted local port range during search? It is not
* possible for us to be holding one of the bind hash
* locks if this test triggers, because if 'remaining'
* drops to zero, we broke out of the do/while loop at
* the top level, not from the 'break;' statement.
*/
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 = &hashinfo->bhash[inet_bhashfn(snum, hashinfo->bhash_size)];
spin_lock(&head->lock);
inet_bind_bucket_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 (inet_csk_bind_conflict(sk, tb))
goto fail_unlock;
}
}
tb_not_found:
ret = 1;
if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, 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 (!inet_csk(sk)->icsk_bind_hash)
inet_bind_hash(sk, tb, snum);
BUG_TRAP(inet_csk(sk)->icsk_bind_hash == tb);
ret = 0;
fail_unlock:
spin_unlock(&head->lock);
fail:
local_bh_enable();
return ret;
}
EXPORT_SYMBOL_GPL(inet_csk_get_port);
/*
* Wait for an incoming connection, avoid race conditions. This must be called
* with the socket locked.
*/
static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
{
struct inet_connection_sock *icsk = inet_csk(sk);
DEFINE_WAIT(wait);
int err;
/*
* True wake-one mechanism for incoming connections: only
* one process gets woken up, not the 'whole herd'.
* Since we do not 'race & poll' for established sockets
* anymore, the common case will execute the loop only once.
*
* Subtle issue: "add_wait_queue_exclusive()" will be added
* after any current non-exclusive waiters, and we know that
* it will always _stay_ after any new non-exclusive waiters
* because all non-exclusive waiters are added at the
* beginning of the wait-queue. As such, it's ok to "drop"
* our exclusiveness temporarily when we get woken up without
* having to remove and re-insert us on the wait queue.
*/
for (;;) {
prepare_to_wait_exclusive(sk->sk_sleep, &wait,
TASK_INTERRUPTIBLE);
release_sock(sk);
if (reqsk_queue_empty(&icsk->icsk_accept_queue))
timeo = schedule_timeout(timeo);
lock_sock(sk);
err = 0;
if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
break;
err = -EINVAL;
if (sk->sk_state != TCP_LISTEN)
break;
err = sock_intr_errno(timeo);
if (signal_pending(current))
break;
err = -EAGAIN;
if (!timeo)
break;
}
finish_wait(sk->sk_sleep, &wait);
return err;
}
/*
* This will accept the next outstanding connection.
*/
struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct sock *newsk;
int error;
lock_sock(sk);
/* We need to make sure that this socket is listening,
* and that it has something pending.
*/
error = -EINVAL;
if (sk->sk_state != TCP_LISTEN)
goto out_err;
/* Find already established connection */
if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
/* If this is a non blocking socket don't sleep */
error = -EAGAIN;
if (!timeo)
goto out_err;
error = inet_csk_wait_for_connect(sk, timeo);
if (error)
goto out_err;
}
newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
out:
release_sock(sk);
return newsk;
out_err:
newsk = NULL;
*err = error;
goto out;
}
EXPORT_SYMBOL(inet_csk_accept);
/*
* Using different timers for retransmit, delayed acks and probes
* We may wish use just one timer maintaining a list of expire jiffies
* to optimize.
*/
void inet_csk_init_xmit_timers(struct sock *sk,
void (*retransmit_handler)(unsigned long),
void (*delack_handler)(unsigned long),
void (*keepalive_handler)(unsigned long))
{
struct inet_connection_sock *icsk = inet_csk(sk);
init_timer(&icsk->icsk_retransmit_timer);
init_timer(&icsk->icsk_delack_timer);
init_timer(&sk->sk_timer);
icsk->icsk_retransmit_timer.function = retransmit_handler;
icsk->icsk_delack_timer.function = delack_handler;
sk->sk_timer.function = keepalive_handler;
icsk->icsk_retransmit_timer.data =
icsk->icsk_delack_timer.data =
sk->sk_timer.data = (unsigned long)sk;
icsk->icsk_pending = icsk->icsk_ack.pending = 0;
}
EXPORT_SYMBOL(inet_csk_init_xmit_timers);
void inet_csk_clear_xmit_timers(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
sk_stop_timer(sk, &icsk->icsk_delack_timer);
sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
void inet_csk_delete_keepalive_timer(struct sock *sk)
{
sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
{
sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
}
EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
struct dst_entry* inet_csk_route_req(struct sock *sk,
const struct request_sock *req)
{
struct rtable *rt;
const struct inet_request_sock *ireq = inet_rsk(req);
struct ip_options *opt = inet_rsk(req)->opt;
struct flowi fl = { .oif = sk->sk_bound_dev_if,
.nl_u = { .ip4_u =
{ .daddr = ((opt && opt->srr) ?
opt->faddr :
ireq->rmt_addr),
.saddr = ireq->loc_addr,
.tos = RT_CONN_FLAGS(sk) } },
.proto = sk->sk_protocol,
.uli_u = { .ports =
{ .sport = inet_sk(sk)->sport,
.dport = ireq->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;
}
EXPORT_SYMBOL_GPL(inet_csk_route_req);
static inline u32 inet_synq_hash(const u32 raddr, const u16 rport,
const u32 rnd, const u16 synq_hsize)
{
return jhash_2words(raddr, (u32)rport, rnd) & (synq_hsize - 1);
}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
#else
#define AF_INET_FAMILY(fam) 1
#endif
struct request_sock *inet_csk_search_req(const struct sock *sk,
struct request_sock ***prevp,
const __u16 rport, const __u32 raddr,
const __u32 laddr)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
struct request_sock *req, **prev;
for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
lopt->nr_table_entries)];
(req = *prev) != NULL;
prev = &req->dl_next) {
const struct inet_request_sock *ireq = inet_rsk(req);
if (ireq->rmt_port == rport &&
ireq->rmt_addr == raddr &&
ireq->loc_addr == laddr &&
AF_INET_FAMILY(req->rsk_ops->family)) {
BUG_TRAP(!req->sk);
*prevp = prev;
break;
}
}
return req;
}
EXPORT_SYMBOL_GPL(inet_csk_search_req);
void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
const unsigned timeout)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
lopt->hash_rnd, lopt->nr_table_entries);
reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
inet_csk_reqsk_queue_added(sk, timeout);
}
/* Only thing we need from tcp.h */
extern int sysctl_tcp_synack_retries;
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
void inet_csk_reqsk_queue_prune(struct sock *parent,
const unsigned long interval,
const unsigned long timeout,
const unsigned long max_rto)
{
struct inet_connection_sock *icsk = inet_csk(parent);
struct request_sock_queue *queue = &icsk->icsk_accept_queue;
struct listen_sock *lopt = queue->listen_opt;
int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
int thresh = max_retries;
unsigned long now = jiffies;
struct request_sock **reqp, *req;
int i, budget;
if (lopt == NULL || lopt->qlen == 0)
return;
/* Normally all the openreqs are young and become mature
* (i.e. converted to established socket) for first timeout.
* If synack was not acknowledged for 3 seconds, it means
* one of the following things: synack was lost, ack was lost,
* rtt is high or nobody planned to ack (i.e. synflood).
* When server is a bit loaded, queue is populated with old
* open requests, reducing effective size of queue.
* When server is well loaded, queue size reduces to zero
* after several minutes of work. It is not synflood,
* it is normal operation. The solution is pruning
* too old entries overriding normal timeout, when
* situation becomes dangerous.
*
* Essentially, we reserve half of room for young
* embrions; and abort old ones without pity, if old
* ones are about to clog our table.
*/
if (lopt->qlen>>(lopt->max_qlen_log-1)) {
int young = (lopt->qlen_young<<1);
while (thresh > 2) {
if (lopt->qlen < young)
break;
thresh--;
young <<= 1;
}
}
if (queue->rskq_defer_accept)
max_retries = queue->rskq_defer_accept;
budget = 2 * (lopt->nr_table_entries / (timeout / interval));
i = lopt->clock_hand;
do {
reqp=&lopt->syn_table[i];
while ((req = *reqp) != NULL) {
if (time_after_eq(now, req->expires)) {
if ((req->retrans < thresh ||
(inet_rsk(req)->acked && req->retrans < max_retries))
&& !req->rsk_ops->rtx_syn_ack(parent, req, NULL)) {
unsigned long timeo;
if (req->retrans++ == 0)
lopt->qlen_young--;
timeo = min((timeout << req->retrans), max_rto);
req->expires = now + timeo;
reqp = &req->dl_next;
continue;
}
/* Drop this request */
inet_csk_reqsk_queue_unlink(parent, req, reqp);
reqsk_queue_removed(queue, req);
reqsk_free(req);
continue;
}
reqp = &req->dl_next;
}
i = (i + 1) & (lopt->nr_table_entries - 1);
} while (--budget > 0);
lopt->clock_hand = i;
if (lopt->qlen)
inet_csk_reset_keepalive_timer(parent, interval);
}
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
const gfp_t priority)
{
struct sock *newsk = sk_clone(sk, priority);
if (newsk != NULL) {
struct inet_connection_sock *newicsk = inet_csk(newsk);
newsk->sk_state = TCP_SYN_RECV;
newicsk->icsk_bind_hash = NULL;
inet_sk(newsk)->dport = inet_rsk(req)->rmt_port;
newsk->sk_write_space = sk_stream_write_space;
newicsk->icsk_retransmits = 0;
newicsk->icsk_backoff = 0;
newicsk->icsk_probes_out = 0;
/* Deinitialize accept_queue to trap illegal accesses. */
memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
}
return newsk;
}
EXPORT_SYMBOL_GPL(inet_csk_clone);
/*
* At this point, there should be no process reference to this
* socket, and thus no user references at all. Therefore we
* can assume the socket waitqueue is inactive and nobody will
* try to jump onto it.
*/
void inet_csk_destroy_sock(struct sock *sk)
{
BUG_TRAP(sk->sk_state == TCP_CLOSE);
BUG_TRAP(sock_flag(sk, SOCK_DEAD));
/* It cannot be in hash table! */
BUG_TRAP(sk_unhashed(sk));
/* If it has not 0 inet_sk(sk)->num, it must be bound */
BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash);
sk->sk_prot->destroy(sk);
sk_stream_kill_queues(sk);
xfrm_sk_free_policy(sk);
sk_refcnt_debug_release(sk);
atomic_dec(sk->sk_prot->orphan_count);
sock_put(sk);
}
EXPORT_SYMBOL(inet_csk_destroy_sock);
int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
{
struct inet_sock *inet = inet_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
if (rc != 0)
return rc;
sk->sk_max_ack_backlog = 0;
sk->sk_ack_backlog = 0;
inet_csk_delack_init(sk);
/* There is race window here: we announce ourselves listening,
* but this transition is still not validated by get_port().
* It is OK, because this socket enters to hash table only
* after validation is complete.
*/
sk->sk_state = TCP_LISTEN;
if (!sk->sk_prot->get_port(sk, inet->num)) {
inet->sport = htons(inet->num);
sk_dst_reset(sk);
sk->sk_prot->hash(sk);
return 0;
}
sk->sk_state = TCP_CLOSE;
__reqsk_queue_destroy(&icsk->icsk_accept_queue);
return -EADDRINUSE;
}
EXPORT_SYMBOL_GPL(inet_csk_listen_start);
/*
* This routine closes sockets which have been at least partially
* opened, but not yet accepted.
*/
void inet_csk_listen_stop(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct request_sock *acc_req;
struct request_sock *req;
inet_csk_delete_keepalive_timer(sk);
/* make all the listen_opt local to us */
acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
/* Following specs, it would be better either to send FIN
* (and enter FIN-WAIT-1, it is normal close)
* or to send active reset (abort).
* Certainly, it is pretty dangerous while synflood, but it is
* bad justification for our negligence 8)
* To be honest, we are not able to make either
* of the variants now. --ANK
*/
reqsk_queue_destroy(&icsk->icsk_accept_queue);
while ((req = acc_req) != NULL) {
struct sock *child = req->sk;
acc_req = req->dl_next;
local_bh_disable();
bh_lock_sock(child);
BUG_TRAP(!sock_owned_by_user(child));
sock_hold(child);
sk->sk_prot->disconnect(child, O_NONBLOCK);
sock_orphan(child);
atomic_inc(sk->sk_prot->orphan_count);
inet_csk_destroy_sock(child);
bh_unlock_sock(child);
local_bh_enable();
sock_put(child);
sk_acceptq_removed(sk);
__reqsk_free(req);
}
BUG_TRAP(!sk->sk_ack_backlog);
}
EXPORT_SYMBOL_GPL(inet_csk_listen_stop);