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kernel / pub / scm / linux / kernel / git / davem / netdev-vger-cvs / f609a8d12c6012f738e55dc5eb232514a44f6ef3 / . / net / ipv4 / tcp.c
blob: 3d4c2b8c68c6c76eea83eb84378e8b68487d30ae [file] [log] [blame]
/*
* 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.c,v 1.185 2001-01-29 22:02:52 davem Exp $
*
* Authors: Ross Biro, <bir7@leland.Stanford.Edu>
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Mark Evans, <evansmp@uhura.aston.ac.uk>
* Corey Minyard <wf-rch!minyard@relay.EU.net>
* Florian La Roche, <flla@stud.uni-sb.de>
* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
* Linus Torvalds, <torvalds@cs.helsinki.fi>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
* Matthew Dillon, <dillon@apollo.west.oic.com>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Jorge Cwik, <jorge@laser.satlink.net>
*
* Fixes:
* Alan Cox : Numerous verify_area() calls
* Alan Cox : Set the ACK bit on a reset
* Alan Cox : Stopped it crashing if it closed while
* sk->inuse=1 and was trying to connect
* (tcp_err()).
* Alan Cox : All icmp error handling was broken
* pointers passed where wrong and the
* socket was looked up backwards. Nobody
* tested any icmp error code obviously.
* Alan Cox : tcp_err() now handled properly. It
* wakes people on errors. poll
* behaves and the icmp error race
* has gone by moving it into sock.c
* Alan Cox : tcp_send_reset() fixed to work for
* everything not just packets for
* unknown sockets.
* Alan Cox : tcp option processing.
* Alan Cox : Reset tweaked (still not 100%) [Had
* syn rule wrong]
* Herp Rosmanith : More reset fixes
* Alan Cox : No longer acks invalid rst frames.
* Acking any kind of RST is right out.
* Alan Cox : Sets an ignore me flag on an rst
* receive otherwise odd bits of prattle
* escape still
* Alan Cox : Fixed another acking RST frame bug.
* Should stop LAN workplace lockups.
* Alan Cox : Some tidyups using the new skb list
* facilities
* Alan Cox : sk->keepopen now seems to work
* Alan Cox : Pulls options out correctly on accepts
* Alan Cox : Fixed assorted sk->rqueue->next errors
* Alan Cox : PSH doesn't end a TCP read. Switched a
* bit to skb ops.
* Alan Cox : Tidied tcp_data to avoid a potential
* nasty.
* Alan Cox : Added some better commenting, as the
* tcp is hard to follow
* Alan Cox : Removed incorrect check for 20 * psh
* Michael O'Reilly : ack < copied bug fix.
* Johannes Stille : Misc tcp fixes (not all in yet).
* Alan Cox : FIN with no memory -> CRASH
* Alan Cox : Added socket option proto entries.
* Also added awareness of them to accept.
* Alan Cox : Added TCP options (SOL_TCP)
* Alan Cox : Switched wakeup calls to callbacks,
* so the kernel can layer network
* sockets.
* Alan Cox : Use ip_tos/ip_ttl settings.
* Alan Cox : Handle FIN (more) properly (we hope).
* Alan Cox : RST frames sent on unsynchronised
* state ack error.
* Alan Cox : Put in missing check for SYN bit.
* Alan Cox : Added tcp_select_window() aka NET2E
* window non shrink trick.
* Alan Cox : Added a couple of small NET2E timer
* fixes
* Charles Hedrick : TCP fixes
* Toomas Tamm : TCP window fixes
* Alan Cox : Small URG fix to rlogin ^C ack fight
* Charles Hedrick : Rewrote most of it to actually work
* Linus : Rewrote tcp_read() and URG handling
* completely
* Gerhard Koerting: Fixed some missing timer handling
* Matthew Dillon : Reworked TCP machine states as per RFC
* Gerhard Koerting: PC/TCP workarounds
* Adam Caldwell : Assorted timer/timing errors
* Matthew Dillon : Fixed another RST bug
* Alan Cox : Move to kernel side addressing changes.
* Alan Cox : Beginning work on TCP fastpathing
* (not yet usable)
* Arnt Gulbrandsen: Turbocharged tcp_check() routine.
* Alan Cox : TCP fast path debugging
* Alan Cox : Window clamping
* Michael Riepe : Bug in tcp_check()
* Matt Dillon : More TCP improvements and RST bug fixes
* Matt Dillon : Yet more small nasties remove from the
* TCP code (Be very nice to this man if
* tcp finally works 100%) 8)
* Alan Cox : BSD accept semantics.
* Alan Cox : Reset on closedown bug.
* Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
* Michael Pall : Handle poll() after URG properly in
* all cases.
* Michael Pall : Undo the last fix in tcp_read_urg()
* (multi URG PUSH broke rlogin).
* Michael Pall : Fix the multi URG PUSH problem in
* tcp_readable(), poll() after URG
* works now.
* Michael Pall : recv(...,MSG_OOB) never blocks in the
* BSD api.
* Alan Cox : Changed the semantics of sk->socket to
* fix a race and a signal problem with
* accept() and async I/O.
* Alan Cox : Relaxed the rules on tcp_sendto().
* Yury Shevchuk : Really fixed accept() blocking problem.
* Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
* clients/servers which listen in on
* fixed ports.
* Alan Cox : Cleaned the above up and shrank it to
* a sensible code size.
* Alan Cox : Self connect lockup fix.
* Alan Cox : No connect to multicast.
* Ross Biro : Close unaccepted children on master
* socket close.
* Alan Cox : Reset tracing code.
* Alan Cox : Spurious resets on shutdown.
* Alan Cox : Giant 15 minute/60 second timer error
* Alan Cox : Small whoops in polling before an
* accept.
* Alan Cox : Kept the state trace facility since
* it's handy for debugging.
* Alan Cox : More reset handler fixes.
* Alan Cox : Started rewriting the code based on
* the RFC's for other useful protocol
* references see: Comer, KA9Q NOS, and
* for a reference on the difference
* between specifications and how BSD
* works see the 4.4lite source.
* A.N.Kuznetsov : Don't time wait on completion of tidy
* close.
* Linus Torvalds : Fin/Shutdown & copied_seq changes.
* Linus Torvalds : Fixed BSD port reuse to work first syn
* Alan Cox : Reimplemented timers as per the RFC
* and using multiple timers for sanity.
* Alan Cox : Small bug fixes, and a lot of new
* comments.
* Alan Cox : Fixed dual reader crash by locking
* the buffers (much like datagram.c)
* Alan Cox : Fixed stuck sockets in probe. A probe
* now gets fed up of retrying without
* (even a no space) answer.
* Alan Cox : Extracted closing code better
* Alan Cox : Fixed the closing state machine to
* resemble the RFC.
* Alan Cox : More 'per spec' fixes.
* Jorge Cwik : Even faster checksumming.
* Alan Cox : tcp_data() doesn't ack illegal PSH
* only frames. At least one pc tcp stack
* generates them.
* Alan Cox : Cache last socket.
* Alan Cox : Per route irtt.
* Matt Day : poll()->select() match BSD precisely on error
* Alan Cox : New buffers
* Marc Tamsky : Various sk->prot->retransmits and
* sk->retransmits misupdating fixed.
* Fixed tcp_write_timeout: stuck close,
* and TCP syn retries gets used now.
* Mark Yarvis : In tcp_read_wakeup(), don't send an
* ack if state is TCP_CLOSED.
* Alan Cox : Look up device on a retransmit - routes may
* change. Doesn't yet cope with MSS shrink right
* but its a start!
* Marc Tamsky : Closing in closing fixes.
* Mike Shaver : RFC1122 verifications.
* Alan Cox : rcv_saddr errors.
* Alan Cox : Block double connect().
* Alan Cox : Small hooks for enSKIP.
* Alexey Kuznetsov: Path MTU discovery.
* Alan Cox : Support soft errors.
* Alan Cox : Fix MTU discovery pathological case
* when the remote claims no mtu!
* Marc Tamsky : TCP_CLOSE fix.
* Colin (G3TNE) : Send a reset on syn ack replies in
* window but wrong (fixes NT lpd problems)
* Pedro Roque : Better TCP window handling, delayed ack.
* Joerg Reuter : No modification of locked buffers in
* tcp_do_retransmit()
* Eric Schenk : Changed receiver side silly window
* avoidance algorithm to BSD style
* algorithm. This doubles throughput
* against machines running Solaris,
* and seems to result in general
* improvement.
* Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
* Willy Konynenberg : Transparent proxying support.
* Mike McLagan : Routing by source
* Keith Owens : Do proper merging with partial SKB's in
* tcp_do_sendmsg to avoid burstiness.
* Eric Schenk : Fix fast close down bug with
* shutdown() followed by close().
* Andi Kleen : Make poll agree with SIGIO
* Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
* lingertime == 0 (RFC 793 ABORT Call)
*
* 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.
*
* Description of States:
*
* TCP_SYN_SENT sent a connection request, waiting for ack
*
* TCP_SYN_RECV received a connection request, sent ack,
* waiting for final ack in three-way handshake.
*
* TCP_ESTABLISHED connection established
*
* TCP_FIN_WAIT1 our side has shutdown, waiting to complete
* transmission of remaining buffered data
*
* TCP_FIN_WAIT2 all buffered data sent, waiting for remote
* to shutdown
*
* TCP_CLOSING both sides have shutdown but we still have
* data we have to finish sending
*
* TCP_TIME_WAIT timeout to catch resent junk before entering
* closed, can only be entered from FIN_WAIT2
* or CLOSING. Required because the other end
* may not have gotten our last ACK causing it
* to retransmit the data packet (which we ignore)
*
* TCP_CLOSE_WAIT remote side has shutdown and is waiting for
* us to finish writing our data and to shutdown
* (we have to close() to move on to LAST_ACK)
*
* TCP_LAST_ACK out side has shutdown after remote has
* shutdown. There may still be data in our
* buffer that we have to finish sending
*
* TCP_CLOSE socket is finished
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <asm/uaccess.h>
int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
struct tcp_mib tcp_statistics[NR_CPUS*2];
kmem_cache_t *tcp_openreq_cachep;
kmem_cache_t *tcp_bucket_cachep;
kmem_cache_t *tcp_timewait_cachep;
atomic_t tcp_orphan_count = ATOMIC_INIT(0);
int sysctl_tcp_mem[3];
int sysctl_tcp_wmem[3] = { 4*1024, 16*1024, 128*1024 };
int sysctl_tcp_rmem[3] = { 4*1024, 87380, 87380*2 };
atomic_t tcp_memory_allocated; /* Current allocated memory. */
atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
/* Pressure flag: try to collapse.
* Technical note: it is used by multiple contexts non atomically.
* All the tcp_mem_schedule() is of this nature: accounting
* is strict, actions are advisory and have some latency. */
int tcp_memory_pressure;
#define TCP_PAGES(amt) (((amt)+TCP_MEM_QUANTUM-1)/TCP_MEM_QUANTUM)
int tcp_mem_schedule(struct sock *sk, int size, int kind)
{
int amt = TCP_PAGES(size);
sk->forward_alloc += amt*TCP_MEM_QUANTUM;
atomic_add(amt, &tcp_memory_allocated);
/* Under limit. */
if (atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
if (tcp_memory_pressure)
tcp_memory_pressure = 0;
return 1;
}
/* Over hard limit. */
if (atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]) {
tcp_enter_memory_pressure();
goto suppress_allocation;
}
/* Under pressure. */
if (atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[1])
tcp_enter_memory_pressure();
if (kind) {
if (atomic_read(&sk->rmem_alloc) < sysctl_tcp_rmem[0])
return 1;
} else {
if (sk->wmem_queued < sysctl_tcp_wmem[0])
return 1;
}
if (!tcp_memory_pressure ||
sysctl_tcp_mem[2] > atomic_read(&tcp_sockets_allocated)
* TCP_PAGES(sk->wmem_queued+atomic_read(&sk->rmem_alloc)+
sk->forward_alloc))
return 1;
suppress_allocation:
if (kind == 0) {
tcp_moderate_sndbuf(sk);
/* Fail only if socket is _under_ its sndbuf.
* In this case we cannot block, so that we have to fail.
*/
if (sk->wmem_queued+size >= sk->sndbuf)
return 1;
}
/* Alas. Undo changes. */
sk->forward_alloc -= amt*TCP_MEM_QUANTUM;
atomic_sub(amt, &tcp_memory_allocated);
return 0;
}
void __tcp_mem_reclaim(struct sock *sk)
{
if (sk->forward_alloc >= TCP_MEM_QUANTUM) {
atomic_sub(sk->forward_alloc/TCP_MEM_QUANTUM, &tcp_memory_allocated);
sk->forward_alloc &= (TCP_MEM_QUANTUM-1);
if (tcp_memory_pressure &&
atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0])
tcp_memory_pressure = 0;
}
}
void tcp_rfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
atomic_sub(skb->truesize, &sk->rmem_alloc);
sk->forward_alloc += skb->truesize;
}
/*
* LISTEN is a special case for poll..
*/
static __inline__ unsigned int tcp_listen_poll(struct sock *sk, poll_table *wait)
{
return sk->tp_pinfo.af_tcp.accept_queue ? (POLLIN | POLLRDNORM) : 0;
}
/*
* Wait for a TCP event.
*
* Note that we don't need to lock the socket, as the upper poll layers
* take care of normal races (between the test and the event) and we don't
* go look at any of the socket buffers directly.
*/
unsigned int tcp_poll(struct file * file, struct socket *sock, poll_table *wait)
{
unsigned int mask;
struct sock *sk = sock->sk;
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
poll_wait(file, sk->sleep, wait);
if (sk->state == TCP_LISTEN)
return tcp_listen_poll(sk, wait);
/* Socket is not locked. We are protected from async events
by poll logic and correct handling of state changes
made by another threads is impossible in any case.
*/
mask = 0;
if (sk->err)
mask = POLLERR;
/*
* POLLHUP is certainly not done right. But poll() doesn't
* have a notion of HUP in just one direction, and for a
* socket the read side is more interesting.
*
* Some poll() documentation says that POLLHUP is incompatible
* with the POLLOUT/POLLWR flags, so somebody should check this
* all. But careful, it tends to be safer to return too many
* bits than too few, and you can easily break real applications
* if you don't tell them that something has hung up!
*
* Check-me.
*
* Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
* our fs/select.c). It means that after we received EOF,
* poll always returns immediately, making impossible poll() on write()
* in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
* if and only if shutdown has been made in both directions.
* Actually, it is interesting to look how Solaris and DUX
* solve this dilemma. I would prefer, if PULLHUP were maskable,
* then we could set it on SND_SHUTDOWN. BTW examples given
* in Stevens' books assume exactly this behaviour, it explains
* why PULLHUP is incompatible with POLLOUT. --ANK
*
* NOTE. Check for TCP_CLOSE is added. The goal is to prevent
* blocking on fresh not-connected or disconnected socket. --ANK
*/
if (sk->shutdown == SHUTDOWN_MASK || sk->state == TCP_CLOSE)
mask |= POLLHUP;
if (sk->shutdown & RCV_SHUTDOWN)
mask |= POLLIN | POLLRDNORM;
/* Connected? */
if ((1 << sk->state) & ~(TCPF_SYN_SENT|TCPF_SYN_RECV)) {
/* Potential race condition. If read of tp below will
* escape above sk->state, we can be illegally awaken
* in SYN_* states. */
if ((tp->rcv_nxt != tp->copied_seq) &&
(tp->urg_seq != tp->copied_seq ||
tp->rcv_nxt != tp->copied_seq+1 ||
sk->urginline || !tp->urg_data))
mask |= POLLIN | POLLRDNORM;
if (!(sk->shutdown & SEND_SHUTDOWN)) {
if (tcp_wspace(sk) >= tcp_min_write_space(sk)) {
mask |= POLLOUT | POLLWRNORM;
} else { /* send SIGIO later */
set_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
set_bit(SOCK_NOSPACE, &sk->socket->flags);
/* Race breaker. If space is freed after
* wspace test but before the flags are set,
* IO signal will be lost.
*/
if (tcp_wspace(sk) >= tcp_min_write_space(sk))
mask |= POLLOUT | POLLWRNORM;
}
}
if (tp->urg_data & TCP_URG_VALID)
mask |= POLLPRI;
}
return mask;
}
/*
* TCP socket write_space callback. Not used.
*/
void tcp_write_space(struct sock *sk)
{
}
int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
int answ;
switch(cmd) {
case SIOCINQ:
if (sk->state == TCP_LISTEN)
return(-EINVAL);
lock_sock(sk);
if ((1<<sk->state) & (TCPF_SYN_SENT|TCPF_SYN_RECV))
answ = 0;
else if (sk->urginline || !tp->urg_data ||
before(tp->urg_seq,tp->copied_seq) ||
!before(tp->urg_seq,tp->rcv_nxt)) {
answ = tp->rcv_nxt - tp->copied_seq;
/* Subtract 1, if FIN is in queue. */
if (answ && !skb_queue_empty(&sk->receive_queue))
answ -= ((struct sk_buff*)sk->receive_queue.prev)->h.th->fin;
} else
answ = tp->urg_seq - tp->copied_seq;
release_sock(sk);
break;
case SIOCATMARK:
{
answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
break;
}
case SIOCOUTQ:
if (sk->state == TCP_LISTEN)
return(-EINVAL);
if ((1<<sk->state) & (TCPF_SYN_SENT|TCPF_SYN_RECV))
answ = 0;
else
answ = tp->write_seq - tp->snd_una;
break;
default:
return(-ENOIOCTLCMD);
};
return put_user(answ, (int *)arg);
}
int tcp_listen_start(struct sock *sk)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
struct tcp_listen_opt *lopt;
sk->max_ack_backlog = 0;
sk->ack_backlog = 0;
tp->accept_queue = tp->accept_queue_tail = NULL;
tp->syn_wait_lock = RW_LOCK_UNLOCKED;
lopt = kmalloc(sizeof(struct tcp_listen_opt), GFP_KERNEL);
if (!lopt)
return -ENOMEM;
memset(lopt, 0, sizeof(struct tcp_listen_opt));
for (lopt->max_qlen_log = 6; ; lopt->max_qlen_log++)
if ((1<<lopt->max_qlen_log) >= sysctl_max_syn_backlog)
break;
write_lock_bh(&tp->syn_wait_lock);
tp->listen_opt = lopt;
write_unlock_bh(&tp->syn_wait_lock);
/* 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->state = TCP_LISTEN;
if (sk->prot->get_port(sk, sk->num) == 0) {
sk->sport = htons(sk->num);
sk_dst_reset(sk);
sk->prot->hash(sk);
return 0;
}
sk->state = TCP_CLOSE;
write_lock_bh(&tp->syn_wait_lock);
tp->listen_opt = NULL;
write_unlock_bh(&tp->syn_wait_lock);
kfree(lopt);
return -EADDRINUSE;
}
/*
* This routine closes sockets which have been at least partially
* opened, but not yet accepted.
*/
static void tcp_listen_stop (struct sock *sk)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
struct tcp_listen_opt *lopt = tp->listen_opt;
struct open_request *acc_req = tp->accept_queue;
struct open_request *req;
int i;
tcp_delete_keepalive_timer(sk);
/* make all the listen_opt local to us */
write_lock_bh(&tp->syn_wait_lock);
tp->listen_opt =NULL;
write_unlock_bh(&tp->syn_wait_lock);
tp->accept_queue = tp->accept_queue_tail = NULL;
if (lopt->qlen) {
for (i=0; i<TCP_SYNQ_HSIZE; i++) {
while ((req = lopt->syn_table[i]) != NULL) {
lopt->syn_table[i] = req->dl_next;
lopt->qlen--;
tcp_openreq_free(req);
/* 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
*/
}
}
}
BUG_TRAP(lopt->qlen == 0);
kfree(lopt);
while ((req=acc_req) != NULL) {
struct sock *child = req->sk;
acc_req = req->dl_next;
local_bh_disable();
bh_lock_sock(child);
BUG_TRAP(child->lock.users==0);
sock_hold(child);
tcp_disconnect(child, O_NONBLOCK);
sock_orphan(child);
atomic_inc(&tcp_orphan_count);
tcp_destroy_sock(child);
bh_unlock_sock(child);
local_bh_enable();
sock_put(child);
tcp_acceptq_removed(sk);
tcp_openreq_fastfree(req);
}
BUG_TRAP(sk->ack_backlog == 0);
}
/*
* Wait for a socket to get into the connected state
*
* Note: Must be called with the socket locked.
*/
static int wait_for_tcp_connect(struct sock * sk, int flags, long *timeo_p)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
while((1 << sk->state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
if(sk->err)
return sock_error(sk);
if((1 << sk->state) &
~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
if(sk->keepopen && !(flags&MSG_NOSIGNAL))
send_sig(SIGPIPE, tsk, 0);
return -EPIPE;
}
if(!*timeo_p)
return -EAGAIN;
if(signal_pending(tsk))
return sock_intr_errno(*timeo_p);
__set_task_state(tsk, TASK_INTERRUPTIBLE);
add_wait_queue(sk->sleep, &wait);
sk->tp_pinfo.af_tcp.write_pending++;
release_sock(sk);
*timeo_p = schedule_timeout(*timeo_p);
lock_sock(sk);
__set_task_state(tsk, TASK_RUNNING);
remove_wait_queue(sk->sleep, &wait);
sk->tp_pinfo.af_tcp.write_pending--;
}
return 0;
}
static inline int tcp_memory_free(struct sock *sk)
{
return sk->wmem_queued < sk->sndbuf;
}
/*
* Wait for more memory for a socket
*/
static long wait_for_tcp_memory(struct sock * sk, long timeo)
{
long vm_wait = 0;
long current_timeo = timeo;
DECLARE_WAITQUEUE(wait, current);
if (tcp_memory_free(sk))
current_timeo = vm_wait = (net_random()%(HZ/5))+2;
clear_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
add_wait_queue(sk->sleep, &wait);
for (;;) {
set_bit(SOCK_NOSPACE, &sk->socket->flags);
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
break;
if (tcp_memory_free(sk) && !vm_wait)
break;
if (sk->shutdown & SEND_SHUTDOWN)
break;
if (sk->err)
break;
release_sock(sk);
if (!tcp_memory_free(sk) || vm_wait)
current_timeo = schedule_timeout(current_timeo);
lock_sock(sk);
if (vm_wait) {
if (timeo != MAX_SCHEDULE_TIMEOUT &&
(timeo -= vm_wait-current_timeo) < 0)
timeo = 0;
break;
} else {
timeo = current_timeo;
}
}
current->state = TASK_RUNNING;
remove_wait_queue(sk->sleep, &wait);
return timeo;
}
/* Inlined constant "new" should remove redundant code in compile time. */
static inline int
skb_add_data(struct sk_buff *skb, char *from, int copy, int new)
{
if (skb->ip_summed == CHECKSUM_HW) {
if(copy_from_user(skb_put(skb, copy), from, copy))
goto fault;
} else {
int err = 0;
unsigned int csum;
if(!new && (skb->len&1)) {
csum =
csum_and_copy_from_user(from, skb_put(skb, copy),
copy, 0, &err);
csum = csum_block_add(skb->csum, csum, 1);
} else {
csum =
csum_and_copy_from_user(from, skb_put(skb, copy),
copy, new?0:skb->csum, &err);
}
if (err)
goto fault;
skb->csum = csum;
}
return 0;
fault:
__skb_trim(skb, skb->len-copy);
return -EFAULT;
}
/* When all user supplied data has been queued set the PSH bit */
#define PSH_NEEDED(flags) (seglen == 0 && iovlen == 0 && !(flags&MSG_MORE))
/*
* This routine copies from a user buffer into a socket,
* and starts the transmit system. It is used only as a
* last resort when the transmitting device does not support
* scatter-gather.
*/
static int tcp_sendmsg_copy(struct sock *sk, struct msghdr *msg, int size)
{
struct iovec *iov;
struct tcp_opt *tp;
struct sk_buff *skb;
int iovlen, flags;
int mss_now;
int err, copied;
long timeo;
err = 0;
tp = &(sk->tp_pinfo.af_tcp);
lock_sock(sk);
TCP_CHECK_TIMER(sk);
flags = msg->msg_flags;
timeo = sock_sndtimeo(sk, flags&MSG_DONTWAIT);
/* Wait for a connection to finish. */
if ((1 << sk->state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
if((err = wait_for_tcp_connect(sk, flags, &timeo)) != 0)
goto out_unlock;
/* This should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
mss_now = tcp_current_mss(sk);
/* Ok commence sending. */
iovlen = msg->msg_iovlen;
iov = msg->msg_iov;
copied = 0;
while (--iovlen >= 0) {
int seglen=iov->iov_len;
unsigned char * from=iov->iov_base;
iov++;
while (seglen > 0) {
int copy, queue_it;
/* Stop on errors. */
if (sk->err)
goto do_sock_err;
/* Make sure that we are established. */
if (sk->shutdown & SEND_SHUTDOWN)
goto do_shutdown;
/* Now we need to check if we have a half
* built packet we can tack some data onto.
*/
skb = sk->write_queue.prev;
if (tp->send_head &&
(copy = mss_now - skb->len) > 0) {
if (skb_tailroom(skb) > 0) {
if(copy > skb_tailroom(skb))
copy = skb_tailroom(skb);
if(copy > seglen)
copy = seglen;
err = skb_add_data(skb, from, copy, 0);
if (err)
goto do_fault2;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
from += copy;
copied += copy;
seglen -= copy;
if (PSH_NEEDED(flags) ||
after(tp->write_seq, tp->pushed_seq+(tp->max_window>>1))) {
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq;
}
if (flags&MSG_OOB) {
tp->urg_mode = 1;
tp->snd_up = tp->write_seq;
TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
}
continue;
} else {
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq;
}
}
copy = min(seglen, mss_now);
if (copy < mss_now) {
/* What is happening here is that we want to
* tack on later members of the users iovec
* if possible into a single frame. When we
* leave this loop our we check to see if
* we can send queued frames onto the wire.
*/
queue_it = 1;
} else {
queue_it = 0;
}
skb = NULL;
if (tcp_memory_free(sk))
skb = tcp_alloc_skb(sk, tp->mss_cache, sk->allocation);
if (skb == NULL) {
/* If we didn't get any memory, we need to sleep. */
set_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
set_bit(SOCK_NOSPACE, &sk->socket->flags);
__tcp_push_pending_frames(sk, tp, mss_now, 1);
if (!timeo) {
err = -EAGAIN;
goto do_interrupted;
}
if (signal_pending(current)) {
err = sock_intr_errno(timeo);
goto do_interrupted;
}
timeo = wait_for_tcp_memory(sk, timeo);
/* If SACK's were formed or PMTU events happened,
* we must find out about it.
*/
mss_now = tcp_current_mss(sk);
continue;
}
seglen -= copy;
/* Prepare control bits for TCP header creation engine. */
if (PSH_NEEDED(flags) ||
after(tp->write_seq+copy, tp->pushed_seq+(tp->max_window>>1))) {
TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK|TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq + copy;
} else {
TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
}
TCP_SKB_CB(skb)->sacked = 0;
if (flags & MSG_OOB) {
TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
tp->urg_mode = 1;
tp->snd_up = tp->write_seq + copy;
}
if (sk->route_caps&NETIF_F_NO_CSUM)
skb->ip_summed = CHECKSUM_HW;
err = skb_add_data(skb, from, copy, 1);
if (err)
goto do_fault;
from += copy;
copied += copy;
TCP_SKB_CB(skb)->seq = tp->write_seq;
TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + copy;
/* This advances tp->write_seq for us. */
tcp_send_skb(sk, skb, queue_it, mss_now);
}
}
err = copied;
out:
__tcp_push_pending_frames(sk, tp, mss_now, (flags&MSG_MORE) ? 2 : tp->nonagle);
out_unlock:
TCP_CHECK_TIMER(sk);
release_sock(sk);
return err;
do_sock_err:
if (copied)
err = copied;
else
err = sock_error(sk);
goto out;
do_shutdown:
if (copied)
err = copied;
else {
if (!(flags&MSG_NOSIGNAL))
send_sig(SIGPIPE, current, 0);
err = -EPIPE;
}
goto out;
do_interrupted:
if (copied)
err = copied;
goto out_unlock;
do_fault:
__kfree_skb(skb);
do_fault2:
if (copied)
err = copied;
else
err = -EFAULT;
goto out;
}
#undef PSH_NEEDED
ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, size_t psize, int flags)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
struct sk_buff *skb = NULL;
int mss_now;
int err = 0;
ssize_t copied;
long timeo = sock_sndtimeo(sk, flags&MSG_DONTWAIT);
/* Wait for a connection to finish. */
if ((1 << sk->state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
if((err = wait_for_tcp_connect(sk, 0, &timeo)) != 0)
goto out_err;
clear_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
mss_now = tcp_current_mss(sk);
copied = 0;
while (psize > 0) {
int offset, size, copy;
struct page *page;
/* Stop on errors. */
if (sk->err)
goto do_sock_err;
/* Make sure that we are established. */
if (sk->shutdown & SEND_SHUTDOWN)
goto do_shutdown;
page = pages[poffset/PAGE_SIZE];
offset = poffset % PAGE_SIZE;
size = min(psize, PAGE_SIZE-offset);
/* Now we need to check if we have a half
* built packet we can tack some data onto.
*/
skb = sk->write_queue.prev;
if (tp->send_head &&
(copy = mss_now - skb->len) > 0) {
int full = 0;
int i = skb_shinfo(skb)->nr_frags;
if (i &&
skb_shinfo(skb)->frags[i-1].page == page &&
skb_shinfo(skb)->frags[i-1].page_offset +
skb_shinfo(skb)->frags[i-1].size == offset) {
if (copy > size)
copy = size;
skb_shinfo(skb)->frags[i-1].size += copy;
} else if (i < MAX_SKB_FRAGS) {
if (copy > size)
copy = size;
get_page(page);
skb_shinfo(skb)->frags[i].page = page;
skb_shinfo(skb)->frags[i].page_offset = offset;
skb_shinfo(skb)->frags[i].size = copy;
skb_shinfo(skb)->nr_frags = i+1;
} else {
full = 1;
}
if (full) {
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq;
__tcp_push_pending_frames(sk, tp, mss_now, 1);
} else {
skb->len += copy;
skb->data_len += copy;
skb->ip_summed = CHECKSUM_HW;
copied += copy;
psize -= copy;
poffset += copy;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
if ((psize == 0 && !(flags&MSG_MORE)) ||
after(tp->write_seq, tp->pushed_seq+(tp->max_window>>1))) {
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq;
}
if (flags & MSG_OOB) {
TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
tp->urg_mode = 1;
tp->snd_up = tp->write_seq;
}
if (skb->len==mss_now || i==MAX_SKB_FRAGS-1)
__tcp_push_pending_frames(sk, tp, mss_now, 1);
continue;
}
}
copy = min(size, mss_now);
skb = NULL;
if (tcp_memory_free(sk))
skb = tcp_alloc_pskb(sk, 0, tp->mss_cache, sk->allocation);
if (skb == NULL) {
/* If we didn't get any memory, we need to sleep. */
set_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);
set_bit(SOCK_NOSPACE, &sk->socket->flags);
__tcp_push_pending_frames(sk, tp, mss_now, 1);
if (!timeo) {
err = -EAGAIN;
goto do_interrupted;
}
if (signal_pending(current)) {
err = sock_intr_errno(timeo);
goto do_interrupted;
}
timeo = wait_for_tcp_memory(sk, timeo);
/* If SACK's were formed or PMTU events happened,
* we must find out about it.
*/
mss_now = tcp_current_mss(sk);
continue;
}
get_page(page);
skb_shinfo(skb)->frags[0].page = page;
skb_shinfo(skb)->frags[0].page_offset = offset;
skb_shinfo(skb)->frags[0].size = copy;
skb_shinfo(skb)->nr_frags = 1;
skb->len = copy;
skb->data_len = copy;
skb->ip_summed = CHECKSUM_HW;
copied += copy;
poffset += copy;
psize -= copy;
/* Prepare control bits for TCP header creation engine. */
if ((psize == 0 && !(flags&MSG_MORE)) ||
after(tp->write_seq+copy, tp->pushed_seq+(tp->max_window>>1))) {
TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK|TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq + copy;
} else {
TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
}
if (flags & MSG_OOB) {
TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
tp->urg_mode = 1;
tp->snd_up = tp->write_seq + copy;
}
TCP_SKB_CB(skb)->sacked = 0;
TCP_SKB_CB(skb)->seq = tp->write_seq;
TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + copy;
tcp_send_skb(sk, skb, copy<mss_now, mss_now);
}
err = copied;
out:
__tcp_push_pending_frames(sk, tp, mss_now, (flags&MSG_MORE) ? 2 : tp->nonagle);
out_err:
return err;
do_sock_err:
if(copied)
err = copied;
else
err = sock_error(sk);
goto out;
do_shutdown:
if(copied)
err = copied;
else {
if (!(flags&MSG_NOSIGNAL))
send_sig(SIGPIPE, current, 0);
err = -EPIPE;
}
goto out;
do_interrupted:
if(copied)
err = copied;
goto out_err;
}
ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags)
{
ssize_t res;
struct sock *sk = sock->sk;
lock_sock(sk);
TCP_CHECK_TIMER(sk);
res = do_tcp_sendpages(sk, &page, offset, size, flags);
TCP_CHECK_TIMER(sk);
release_sock(sk);
return res;
}
#define TCP_PAGE(sk) (sk->tp_pinfo.af_tcp.sndmsg_page)
#define TCP_OFF(sk) (sk->tp_pinfo.af_tcp.sndmsg_off)
#define MAXPGS 8
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, int size)
{
struct page *page_list[MAXPGS], *page;
struct iovec *iov;
int copied, iovlen, err, first_off, off;
int npages, pending, free_last;
if ((sk->route_caps & NETIF_F_SG) == 0 ||
(sk->route_caps & (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)) == 0)
return tcp_sendmsg_copy(sk, msg, size);
npages = 0;
copied = 0;
iov = msg->msg_iov;
iovlen = msg->msg_iovlen;
pending = 0;
page = NULL;
first_off = off = 0;
while (--iovlen >= 0) {
int seglen = iov->iov_len;
unsigned char *from = iov->iov_base;
iov++;
while (seglen > 0) {
int copy;
if (page == NULL) {
/* We can use the cached page if we are starting
* a new run of pages or the whole page is available.
*/
lock_sock(sk);
if (TCP_PAGE(sk) &&
(!pending || TCP_OFF(sk) == 0)) {
page = TCP_PAGE(sk);
TCP_PAGE(sk) = NULL;
off = TCP_OFF(sk);
}
release_sock(sk);
/* We need to grab a new page if the cached page
* was unsuitable or had no space left (after
* alignment).
*/
if (page == NULL) {
page = alloc_pages(sk->allocation, 0);
if (page == NULL) {
err = -ENOMEM;
goto out_err;
}
off = 0;
}
/* When starting a new run of pages, init the
* starting page offset.
*/
if (!pending)
first_off = off;
}
/* Determine the size of this stride, and suck the
* data in from userspace.
*/
copy = seglen;
if (copy > (PAGE_SIZE - off))
copy = (PAGE_SIZE - off);
err = -EFAULT;
if (copy_from_user(page_address(page) + off,
from, copy))
goto out_err;
from += copy;
seglen -= copy;
copied += copy;
pending += copy;
off += copy;
/* Have we consumsed the entire current page? */
if (off >= PAGE_SIZE) {
page_list[npages++] = page;
page = NULL;
off = 0;
/* If we filled the local page array, flush
* them out to tcp_sendpages. Let it know if
* we have more user data coming after this
* round.
*/
if (npages == MAXPGS) {
int flags = msg->msg_flags;
int i, pgoff;
if (seglen || iovlen)
flags |= MSG_MORE;
if (pending != (PAGE_SIZE*npages)-first_off)
BUG();
pgoff = 0;
do {
lock_sock(sk);
TCP_CHECK_TIMER(sk);
err = do_tcp_sendpages(sk, &page_list[pgoff],
first_off, pending, flags);
TCP_CHECK_TIMER(sk);
release_sock(sk);
if (err < 0) {
copied -= pending;
goto out_err;
}
pending -= err;
pgoff += (((first_off + err) >> PAGE_SHIFT) -
(first_off >> PAGE_SHIFT));
first_off = (first_off + err) % PAGE_SIZE;
} while (pending > 0);
for (i = 0; i < MAXPGS; i++)
__free_page(page_list[i]);
/* Start a new run of pages. */
npages = 0;
pending = 0;
}
}
}
}
/* If we are in the middle of a run, and in the middle of
* the current page, add that page to the end of the run.
*/
free_last = 1;
if (pending &&
((pending + first_off) % PAGE_SIZE) != 0) {
if (page == NULL)
BUG();
page_list[npages++] = page;
lock_sock(sk);
if (TCP_PAGE(sk) == NULL) {
TCP_PAGE(sk) = page;
TCP_OFF(sk) = off;
page = NULL;
free_last = 0;
}
release_sock(sk);
}
/* Submit the final round of pages to the TCP send engine. */
if (pending) {
int i, pgoff;
if (!npages)
BUG();
pgoff = 0;
do {
lock_sock(sk);
TCP_CHECK_TIMER(sk);
err = do_tcp_sendpages(sk, &page_list[pgoff],
first_off, pending,
msg->msg_flags);
TCP_CHECK_TIMER(sk);
release_sock(sk);
if (err < 0) {
copied -= pending;
if (!free_last)
npages--;
goto out_err;
}
pending -= err;
pgoff += (((first_off + err) >> PAGE_SHIFT) -
(first_off >> PAGE_SHIFT));
first_off = (first_off + err) % PAGE_SIZE;
} while (pending > 0);
if (!free_last)
npages--;
for (i = 0; i < npages; i++)
__free_page(page_list[i]);
}
return copied;
out_err:
{
int i;
for (i = 0; i < npages; i++)
__free_page(page_list[i]);
if (page)
__free_page(page);
}
if (copied)
return copied;
return err;
}
#undef MAXPGS
/*
* Handle reading urgent data. BSD has very simple semantics for
* this, no blocking and very strange errors 8)
*/
static int tcp_recv_urg(struct sock * sk, long timeo,
struct msghdr *msg, int len, int flags,
int *addr_len)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
/* No URG data to read. */
if (sk->urginline || !tp->urg_data || tp->urg_data == TCP_URG_READ)
return -EINVAL; /* Yes this is right ! */
if (sk->state==TCP_CLOSE && !sk->done)
return -ENOTCONN;
if (tp->urg_data & TCP_URG_VALID) {
int err = 0;
char c = tp->urg_data;
if (!(flags & MSG_PEEK))
tp->urg_data = TCP_URG_READ;
/* Read urgent data. */
msg->msg_flags|=MSG_OOB;
if(len>0) {
if (!(flags & MSG_PEEK))
err = memcpy_toiovec(msg->msg_iov, &c, 1);
len = 1;
} else
msg->msg_flags|=MSG_TRUNC;
return err ? -EFAULT : len;
}
if (sk->state == TCP_CLOSE || (sk->shutdown & RCV_SHUTDOWN))
return 0;
/* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
* the available implementations agree in this case:
* this call should never block, independent of the
* blocking state of the socket.
* Mike <pall@rz.uni-karlsruhe.de>
*/
return -EAGAIN;
}
/*
* Release a skb if it is no longer needed. This routine
* must be called with interrupts disabled or with the
* socket locked so that the sk_buff queue operation is ok.
*/
static inline void tcp_eat_skb(struct sock *sk, struct sk_buff * skb)
{
__skb_unlink(skb, &sk->receive_queue);
__kfree_skb(skb);
}
/* Clean up the receive buffer for full frames taken by the user,
* then send an ACK if necessary. COPIED is the number of bytes
* tcp_recvmsg has given to the user so far, it speeds up the
* calculation of whether or not we must ACK for the sake of
* a window update.
*/
static void cleanup_rbuf(struct sock *sk, int copied)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
struct sk_buff *skb;
int time_to_ack = 0;
/* NOTE! The socket must be locked, so that we don't get
* a messed-up receive queue.
*/
while ((skb=skb_peek(&sk->receive_queue)) != NULL) {
if (!skb->used)
break;
tcp_eat_skb(sk, skb);
}
if (tcp_ack_scheduled(tp)) {
/* Delayed ACKs frequently hit locked sockets during bulk receive. */
if (tp->ack.blocked
/* Once-per-two-segments ACK was not sent by tcp_input.c */
|| tp->rcv_nxt - tp->rcv_wup > tp->ack.rcv_mss
/*
* If this read emptied read buffer, we send ACK, if
* connection is not bidirectional, user drained
* receive buffer and there was a small segment
* in queue.
*/
|| (copied > 0 &&
(tp->ack.pending&TCP_ACK_PUSHED) &&
!tp->ack.pingpong &&
atomic_read(&sk->rmem_alloc) == 0)) {
time_to_ack = 1;
}
}
/* We send an ACK if we can now advertise a non-zero window
* which has been raised "significantly".
*
* Even if window raised up to infinity, do not send window open ACK
* in states, where we will not receive more. It is useless.
*/
if(copied > 0 && !time_to_ack && !(sk->shutdown&RCV_SHUTDOWN)) {
__u32 rcv_window_now = tcp_receive_window(tp);
/* Optimize, __tcp_select_window() is not cheap. */
if (2*rcv_window_now <= tp->window_clamp) {
__u32 new_window = __tcp_select_window(sk);
/* Send ACK now, if this read freed lots of space
* in our buffer. Certainly, new_window is new window.
* We can advertise it now, if it is not less than current one.
* "Lots" means "at least twice" here.
*/
if(new_window && new_window >= 2*rcv_window_now)
time_to_ack = 1;
}
}
if (time_to_ack)
tcp_send_ack(sk);
}
/* Now socket state including sk->err is changed only under lock,
* hence we may omit checks after joining wait queue.
* We check receive queue before schedule() only as optimization;
* it is very likely that release_sock() added new data.
*/
static long tcp_data_wait(struct sock *sk, long timeo)
{
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(sk->sleep, &wait);
__set_current_state(TASK_INTERRUPTIBLE);
set_bit(SOCK_ASYNC_WAITDATA, &sk->socket->flags);
release_sock(sk);
if (skb_queue_empty(&sk->receive_queue))
timeo = schedule_timeout(timeo);
lock_sock(sk);
clear_bit(SOCK_ASYNC_WAITDATA, &sk->socket->flags);
remove_wait_queue(sk->sleep, &wait);
__set_current_state(TASK_RUNNING);
return timeo;
}
static void tcp_prequeue_process(struct sock *sk)
{
struct sk_buff *skb;
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
net_statistics[smp_processor_id()*2+1].TCPPrequeued += skb_queue_len(&tp->ucopy.prequeue);
/* RX process wants to run with disabled BHs, though it is not necessary */
local_bh_disable();
while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
sk->backlog_rcv(sk, skb);
local_bh_enable();
/* Clear memory counter. */
tp->ucopy.memory = 0;
}
/*
* This routine copies from a sock struct into the user buffer.
*
* Technical note: in 2.3 we work on _locked_ socket, so that
* tricks with *seq access order and skb->users are not required.
* Probably, code can be easily improved even more.
*/
int tcp_recvmsg(struct sock *sk, struct msghdr *msg,
int len, int nonblock, int flags, int *addr_len)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
int copied = 0;
u32 peek_seq;
u32 *seq;
unsigned long used;
int err;
int target; /* Read at least this many bytes */
long timeo;
struct task_struct *user_recv = NULL;
lock_sock(sk);
TCP_CHECK_TIMER(sk);
err = -ENOTCONN;
if (sk->state == TCP_LISTEN)
goto out;
timeo = sock_rcvtimeo(sk, nonblock);
/* Urgent data needs to be handled specially. */
if (flags & MSG_OOB)
goto recv_urg;
seq = &tp->copied_seq;
if (flags & MSG_PEEK) {
peek_seq = tp->copied_seq;
seq = &peek_seq;
}
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
do {
struct sk_buff * skb;
u32 offset;
/* Are we at urgent data? Stop if we have read anything. */
if (copied && tp->urg_data && tp->urg_seq == *seq)
break;
/* We need to check signals first, to get correct SIGURG
* handling. FIXME: Need to check this doesnt impact 1003.1g
* and move it down to the bottom of the loop
*/
if (signal_pending(current)) {
if (copied)
break;
copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
break;
}
/* Next get a buffer. */
skb = skb_peek(&sk->receive_queue);
do {
if (!skb)
break;
/* Now that we have two receive queues this
* shouldn't happen.
*/
if (before(*seq, TCP_SKB_CB(skb)->seq)) {
printk(KERN_INFO "recvmsg bug: copied %X seq %X\n",
*seq, TCP_SKB_CB(skb)->seq);
break;
}
offset = *seq - TCP_SKB_CB(skb)->seq;
if (skb->h.th->syn)
offset--;
if (offset < skb->len)
goto found_ok_skb;
if (skb->h.th->fin)
goto found_fin_ok;
if (!(flags & MSG_PEEK))
skb->used = 1;
skb = skb->next;
} while (skb != (struct sk_buff *)&sk->receive_queue);
/* Well, if we have backlog, try to process it now yet. */
if (copied >= target && sk->backlog.tail == NULL)
break;
if (copied) {
if (sk->err ||
sk->state == TCP_CLOSE ||
(sk->shutdown & RCV_SHUTDOWN) ||
!timeo)
break;
} else {
if (sk->done)
break;
if (sk->err) {
copied = sock_error(sk);
break;
}
if (sk->shutdown & RCV_SHUTDOWN)
break;
if (sk->state == TCP_CLOSE) {
if (!sk->done) {
/* This occurs when user tries to read
* from never connected socket.
*/
copied = -ENOTCONN;
break;
}
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
}
cleanup_rbuf(sk, copied);
if (tp->ucopy.task == user_recv) {
/* Install new reader */
if (user_recv == NULL && !(flags&(MSG_TRUNC|MSG_PEEK))) {
user_recv = current;
tp->ucopy.task = user_recv;
tp->ucopy.iov = msg->msg_iov;
}
tp->ucopy.len = len;
BUG_TRAP(tp->copied_seq == tp->rcv_nxt || (flags&(MSG_PEEK|MSG_TRUNC)));
/* Ugly... If prequeue is not empty, we have to
* process it before releasing socket, otherwise
* order will be broken at second iteration.
* More elegant solution is required!!!
*
* Look: we have the following (pseudo)queues:
*
* 1. packets in flight
* 2. backlog
* 3. prequeue
* 4. receive_queue
*
* Each queue can be processed only if the next ones
* are empty. At this point we have empty receive_queue.
* But prequeue _can_ be not empty after second iteration,
* when we jumped to start of loop because backlog
* processing added something to receive_queue.
* We cannot release_sock(), because backlog contains
* packets arrived _after_ prequeued ones.
*
* Shortly, algorithm is clear --- to process all
* the queues in order. We could make it more directly,
* requeueing packets from backlog to prequeue, if
* is not empty. It is more elegant, but eats cycles,
* unfortunately.
*/
if (skb_queue_len(&tp->ucopy.prequeue))
goto do_prequeue;
/* __ Set realtime policy in scheduler __ */
}
if (copied >= target) {
/* Do not sleep, just process backlog. */
release_sock(sk);
lock_sock(sk);
} else {
timeo = tcp_data_wait(sk, timeo);
}
if (user_recv) {
int chunk;
/* __ Restore normal policy in scheduler __ */
if ((chunk = len - tp->ucopy.len) != 0) {
net_statistics[smp_processor_id()*2+1].TCPDirectCopyFromBacklog += chunk;
len -= chunk;
copied += chunk;
}
if (tp->rcv_nxt == tp->copied_seq &&
skb_queue_len(&tp->ucopy.prequeue)) {
do_prequeue:
tcp_prequeue_process(sk);
if ((chunk = len - tp->ucopy.len) != 0) {
net_statistics[smp_processor_id()*2+1].TCPDirectCopyFromPrequeue += chunk;
len -= chunk;
copied += chunk;
}
}
}
continue;
found_ok_skb:
/* Ok so how much can we use? */
used = skb->len - offset;
if (len < used)
used = len;
/* Do we have urgent data here? */
if (tp->urg_data) {
u32 urg_offset = tp->urg_seq - *seq;
if (urg_offset < used) {
if (!urg_offset) {
if (!sk->urginline) {
++*seq;
offset++;
used--;
}
} else
used = urg_offset;
}
}
err = 0;
if (!(flags&MSG_TRUNC)) {
err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, used);
if (err) {
/* Exception. Bailout! */
if (!copied)
copied = -EFAULT;
break;
}
}
*seq += used;
copied += used;
len -= used;
if (after(tp->copied_seq,tp->urg_seq)) {
tp->urg_data = 0;
if (skb_queue_len(&tp->out_of_order_queue) == 0
#ifdef TCP_FORMAL_WINDOW
&& tcp_receive_window(tp)
#endif
) {
tcp_fast_path_on(tp);
}
}
if (used + offset < skb->len)
continue;
/* Process the FIN. We may also need to handle PSH
* here and make it break out of MSG_WAITALL.
*/
if (skb->h.th->fin)
goto found_fin_ok;
if (flags & MSG_PEEK)
continue;
skb->used = 1;
tcp_eat_skb(sk, skb);
continue;
found_fin_ok:
++*seq;
if (flags & MSG_PEEK)
break;
/* All is done. */
skb->used = 1;
break;
} while (len > 0);
if (user_recv) {
if (skb_queue_len(&tp->ucopy.prequeue)) {
int chunk;
tp->ucopy.len = copied > 0 ? len : 0;
tcp_prequeue_process(sk);
if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
net_statistics[smp_processor_id()*2+1].TCPDirectCopyFromPrequeue += chunk;
len -= chunk;
copied += chunk;
}
}
tp->ucopy.task = NULL;
tp->ucopy.len = 0;
}
/* According to UNIX98, msg_name/msg_namelen are ignored
* on connected socket. I was just happy when found this 8) --ANK
*/
/* Clean up data we have read: This will do ACK frames. */
cleanup_rbuf(sk, copied);
TCP_CHECK_TIMER(sk);
release_sock(sk);
return copied;
out:
TCP_CHECK_TIMER(sk);
release_sock(sk);
return err;
recv_urg:
err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
goto out;
}
/*
* State processing on a close. This implements the state shift for
* sending our FIN frame. Note that we only send a FIN for some
* states. A shutdown() may have already sent the FIN, or we may be
* closed.
*/
static unsigned char new_state[16] = {
/* current state: new state: action: */
/* (Invalid) */ TCP_CLOSE,
/* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
/* TCP_SYN_SENT */ TCP_CLOSE,
/* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
/* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
/* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
/* TCP_TIME_WAIT */ TCP_CLOSE,
/* TCP_CLOSE */ TCP_CLOSE,
/* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
/* TCP_LAST_ACK */ TCP_LAST_ACK,
/* TCP_LISTEN */ TCP_CLOSE,
/* TCP_CLOSING */ TCP_CLOSING,
};
static int tcp_close_state(struct sock *sk)
{
int next = (int) new_state[sk->state];
int ns = (next & TCP_STATE_MASK);
tcp_set_state(sk, ns);
return (next & TCP_ACTION_FIN);
}
/*
* Shutdown the sending side of a connection. Much like close except
* that we don't receive shut down or set sk->dead.
*/
void tcp_shutdown(struct sock *sk, int how)
{
/* We need to grab some memory, and put together a FIN,
* and then put it into the queue to be sent.
* Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
*/
if (!(how & SEND_SHUTDOWN))
return;
/* If we've already sent a FIN, or it's a closed state, skip this. */
if ((1 << sk->state) &
(TCPF_ESTABLISHED|TCPF_SYN_SENT|TCPF_SYN_RECV|TCPF_CLOSE_WAIT)) {
/* Clear out any half completed packets. FIN if needed. */
if (tcp_close_state(sk))
tcp_send_fin(sk);
}
}
/*
* Return 1 if we still have things to send in our buffers.
*/
static inline int closing(struct sock * sk)
{
return ((1 << sk->state) & (TCPF_FIN_WAIT1|TCPF_CLOSING|TCPF_LAST_ACK));
}
static __inline__ void tcp_kill_sk_queues(struct sock *sk)
{
/* First the read buffer. */
__skb_queue_purge(&sk->receive_queue);
/* Next, the error queue. */
__skb_queue_purge(&sk->error_queue);
/* Next, the write queue. */
BUG_TRAP(skb_queue_empty(&sk->write_queue));
/* Account for returned memory. */
tcp_mem_reclaim(sk);
BUG_TRAP(sk->wmem_queued == 0);
BUG_TRAP(sk->forward_alloc == 0);
/* It is _impossible_ for the backlog to contain anything
* when we get here. All user references to this socket
* have gone away, only the net layer knows can touch it.
*/
}
/*
* 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 tcp_destroy_sock(struct sock *sk)
{
BUG_TRAP(sk->state==TCP_CLOSE);
BUG_TRAP(sk->dead);
/* It cannot be in hash table! */
BUG_TRAP(sk->pprev==NULL);
/* It it has not 0 sk->num, it must be bound */
BUG_TRAP(!sk->num || sk->prev!=NULL);
#ifdef TCP_DEBUG
if (sk->zapped) {
printk("TCP: double destroy sk=%p\n", sk);
sock_hold(sk);
}
sk->zapped = 1;
#endif
sk->prot->destroy(sk);
tcp_kill_sk_queues(sk);
#ifdef INET_REFCNT_DEBUG
if (atomic_read(&sk->refcnt) != 1) {
printk(KERN_DEBUG "Destruction TCP %p delayed, c=%d\n", sk, atomic_read(&sk->refcnt));
}
#endif
atomic_dec(&tcp_orphan_count);
sock_put(sk);
}
void tcp_close(struct sock *sk, long timeout)
{
struct sk_buff *skb;
int data_was_unread = 0;
lock_sock(sk);
sk->shutdown = SHUTDOWN_MASK;
if(sk->state == TCP_LISTEN) {
tcp_set_state(sk, TCP_CLOSE);
/* Special case. */
tcp_listen_stop(sk);
goto adjudge_to_death;
}
/* We need to flush the recv. buffs. We do this only on the
* descriptor close, not protocol-sourced closes, because the
* reader process may not have drained the data yet!
*/
while((skb=__skb_dequeue(&sk->receive_queue))!=NULL) {
u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - skb->h.th->fin;
data_was_unread += len;
__kfree_skb(skb);
}
tcp_mem_reclaim(sk);
/* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
* 3.10, we send a RST here because data was lost. To
* witness the awful effects of the old behavior of always
* doing a FIN, run an older 2.1.x kernel or 2.0.x, start
* a bulk GET in an FTP client, suspend the process, wait
* for the client to advertise a zero window, then kill -9
* the FTP client, wheee... Note: timeout is always zero
* in such a case.
*/
if(data_was_unread != 0) {
/* Unread data was tossed, zap the connection. */
NET_INC_STATS_USER(TCPAbortOnClose);
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_KERNEL);
} else if (sk->linger && sk->lingertime==0) {
/* Check zero linger _after_ checking for unread data. */
sk->prot->disconnect(sk, 0);
NET_INC_STATS_USER(TCPAbortOnData);
} else if (tcp_close_state(sk)) {
/* We FIN if the application ate all the data before
* zapping the connection.
*/
/* RED-PEN. Formally speaking, we have broken TCP state
* machine. State transitions:
*
* TCP_ESTABLISHED -> TCP_FIN_WAIT1
* TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
* TCP_CLOSE_WAIT -> TCP_LAST_ACK
*
* are legal only when FIN has been sent (i.e. in window),
* rather than queued out of window. Purists blame.
*
* F.e. "RFC state" is ESTABLISHED,
* if Linux state is FIN-WAIT-1, but FIN is still not sent.
*
* The visible declinations are that sometimes
* we enter time-wait state, when it is not required really
* (harmless), do not send active resets, when they are
* required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
* they look as CLOSING or LAST_ACK for Linux)
* Probably, I missed some more holelets.
* --ANK
*/
tcp_send_fin(sk);
}
if (timeout) {
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(sk->sleep, &wait);
do {
set_current_state(TASK_INTERRUPTIBLE);
if (!closing(sk))
break;
release_sock(sk);
timeout = schedule_timeout(timeout);
lock_sock(sk);
} while (!signal_pending(tsk) && timeout);
tsk->state = TASK_RUNNING;
remove_wait_queue(sk->sleep, &wait);
}
adjudge_to_death:
/* It is the last release_sock in its life. It will remove backlog. */
release_sock(sk);
/* Now socket is owned by kernel and we acquire BH lock
to finish close. No need to check for user refs.
*/
local_bh_disable();
bh_lock_sock(sk);
BUG_TRAP(sk->lock.users==0);
sock_hold(sk);
sock_orphan(sk);
/* This is a (useful) BSD violating of the RFC. There is a
* problem with TCP as specified in that the other end could
* keep a socket open forever with no application left this end.
* We use a 3 minute timeout (about the same as BSD) then kill
* our end. If they send after that then tough - BUT: long enough
* that we won't make the old 4*rto = almost no time - whoops
* reset mistake.
*
* Nope, it was not mistake. It is really desired behaviour
* f.e. on http servers, when such sockets are useless, but
* consume significant resources. Let's do it with special
* linger2 option. --ANK
*/
if (sk->state == TCP_FIN_WAIT2) {
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
if (tp->linger2 < 0) {
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
NET_INC_STATS_BH(TCPAbortOnLinger);
} else {
int tmo = tcp_fin_time(tp);
if (tmo > TCP_TIMEWAIT_LEN) {
tcp_reset_keepalive_timer(sk, tcp_fin_time(tp));
} else {
atomic_inc(&tcp_orphan_count);
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
goto out;
}
}
}
if (sk->state != TCP_CLOSE) {
tcp_mem_reclaim(sk);
if (atomic_read(&tcp_orphan_count) > sysctl_tcp_max_orphans ||
(sk->wmem_queued > SOCK_MIN_SNDBUF &&
atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
if (net_ratelimit())
printk(KERN_INFO "TCP: too many of orphaned sockets\n");
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
NET_INC_STATS_BH(TCPAbortOnMemory);
}
}
atomic_inc(&tcp_orphan_count);
if (sk->state == TCP_CLOSE)
tcp_destroy_sock(sk);
/* Otherwise, socket is reprieved until protocol close. */
out:
bh_unlock_sock(sk);
local_bh_enable();
sock_put(sk);
}
/* These states need RST on ABORT according to RFC793 */
extern __inline__ int tcp_need_reset(int state)
{
return ((1 << state) &
(TCPF_ESTABLISHED|TCPF_CLOSE_WAIT|TCPF_FIN_WAIT1|
TCPF_FIN_WAIT2|TCPF_SYN_RECV));
}
int tcp_disconnect(struct sock *sk, int flags)
{
struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
int old_state;
int err = 0;
old_state = sk->state;
if (old_state != TCP_CLOSE)
tcp_set_state(sk, TCP_CLOSE);
/* ABORT function of RFC793 */
if (old_state == TCP_LISTEN) {
tcp_listen_stop(sk);
} else if (tcp_need_reset(old_state) ||
(tp->snd_nxt != tp->write_seq &&
(1<<old_state)&(TCPF_CLOSING|TCPF_LAST_ACK))) {
/* The last check adjusts for discrepance of Linux wrt. RFC
* states
*/
tcp_send_active_reset(sk, gfp_any());
sk->err = ECONNRESET;
} else if (old_state == TCP_SYN_SENT)
sk->err = ECONNRESET;
tcp_clear_xmit_timers(sk);
__skb_queue_purge(&sk->receive_queue);
tcp_writequeue_purge(sk);
__skb_queue_purge(&tp->out_of_order_queue);
sk->dport = 0;
if (!(sk->userlocks&SOCK_BINDADDR_LOCK)) {
sk->rcv_saddr = 0;
sk->saddr = 0;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
memset(&sk->net_pinfo.af_inet6.saddr, 0, 16);
memset(&sk->net_pinfo.af_inet6.rcv_saddr, 0, 16);
#endif
}
sk->shutdown = 0;
sk->done = 0;
tp->srtt = 0;
if ((tp->write_seq += tp->max_window+2) == 0)
tp->write_seq = 1;
tp->backoff = 0;
tp->snd_cwnd = 2;
tp->probes_out = 0;
tp->packets_out = 0;
tp->snd_ssthresh = 0x7fffffff;
tp->snd_cwnd_cnt = 0;
tp->ca_state = TCP_CA_Open;
tcp_clear_retrans(tp);
tcp_delack_init(tp);
tp->send_head = NULL;
tp->saw_tstamp = 0;
tcp_sack_reset(tp);
__sk_dst_reset(sk);
BUG_TRAP(!sk->num || sk->prev);
sk->error_report(sk);
return err;
}
/*
* Wait for an incoming connection, avoid race
* conditions. This must be called with the socket locked.
*/
static int wait_for_connect(struct sock * sk, long timeo)
{
DECLARE_WAITQUEUE(wait, current);
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.
*/
add_wait_queue_exclusive(sk->sleep, &wait);
for (;;) {
current->state = TASK_INTERRUPTIBLE;
release_sock(sk);
if (sk->tp_pinfo.af_tcp.accept_queue == NULL)
timeo = schedule_timeout(timeo);
lock_sock(sk);
err = 0;
if (sk->tp_pinfo.af_tcp.accept_queue)
break;
err = -EINVAL;
if (sk->state != TCP_LISTEN)
break;
err = sock_intr_errno(timeo);
if (signal_pending(current))
break;
err = -EAGAIN;
if (!timeo)
break;
}
current->state = TASK_RUNNING;
remove_wait_queue(sk->sleep, &wait);
return err;
}
/*
* This will accept the next outstanding connection.
*/
struct sock *tcp_accept(struct sock *sk, int flags, int *err)
{
struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
struct open_request *req;
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->state != TCP_LISTEN)
goto out;
/* Find already established connection */
if (!tp->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;
error = wait_for_connect(sk, timeo);
if (error)
goto out;
}
req = tp->accept_queue;
if ((tp->accept_queue = req->dl_next) == NULL)
tp->accept_queue_tail = NULL;
newsk = req->sk;
tcp_acceptq_removed(sk);
tcp_openreq_fastfree(req);
BUG_TRAP(newsk->state != TCP_SYN_RECV);
release_sock(sk);
return newsk;
out:
release_sock(sk);
*err = error;
return NULL;
}
/*
* Socket option code for TCP.
*/
int tcp_setsockopt(struct sock *sk, int level, int optname, char *optval,
int optlen)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
int val;
int err = 0;
if (level != SOL_TCP)
return tp->af_specific->setsockopt(sk, level, optname,
optval, optlen);
if(optlen<sizeof(int))
return -EINVAL;
if (get_user(val, (int *)optval))
return -EFAULT;
lock_sock(sk);
switch(optname) {
case TCP_MAXSEG:
/* values greater than interface MTU won't take effect. however at
* the point when this call is done we typically don't yet know
* which interface is going to be used
*/
if(val < 8 || val > MAX_TCP_WINDOW) {
err = -EINVAL;
break;
}
tp->user_mss = val;
break;
case TCP_NODELAY:
/* You cannot try to use this and TCP_CORK in
* tandem, so let the user know.
*/
if (tp->nonagle == 2) {
err = -EINVAL;
break;
}
tp->nonagle = (val == 0) ? 0 : 1;
if (val)
tcp_push_pending_frames(sk, tp);
break;
case TCP_CORK:
/* When set indicates to always queue non-full frames.
* Later the user clears this option and we transmit
* any pending partial frames in the queue. This is
* meant to be used alongside sendfile() to get properly
* filled frames when the user (for example) must write
* out headers with a write() call first and then use
* sendfile to send out the data parts.
*
* You cannot try to use TCP_NODELAY and this mechanism
* at the same time, so let the user know.
*/
if (tp->nonagle == 1) {
err = -EINVAL;
break;
}
if (val != 0) {
tp->nonagle = 2;
} else {
tp->nonagle = 0;
tcp_push_pending_frames(sk, tp);
}
break;
case TCP_KEEPIDLE:
if (val < 1 || val > MAX_TCP_KEEPIDLE)
err = -EINVAL;
else {
tp->keepalive_time = val * HZ;
if (sk->keepopen && !((1<<sk->state)&(TCPF_CLOSE|TCPF_LISTEN))) {
__u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
if (tp->keepalive_time > elapsed)
elapsed = tp->keepalive_time - elapsed;
else
elapsed = 0;
tcp_reset_keepalive_timer(sk, elapsed);
}
}
break;
case TCP_KEEPINTVL:
if (val < 1 || val > MAX_TCP_KEEPINTVL)
err = -EINVAL;
else
tp->keepalive_intvl = val * HZ;
break;
case TCP_KEEPCNT:
if (val < 1 || val > MAX_TCP_KEEPCNT)
err = -EINVAL;
else
tp->keepalive_probes = val;
break;
case TCP_SYNCNT:
if (val < 1 || val > MAX_TCP_SYNCNT)
err = -EINVAL;
else
tp->syn_retries = val;
break;
case TCP_LINGER2:
if (val < 0)
tp->linger2 = -1;
else if (val > sysctl_tcp_fin_timeout/HZ)
tp->linger2 = 0;
else
tp->linger2 = val*HZ;
break;
case TCP_DEFER_ACCEPT:
tp->defer_accept = 0;
if (val > 0) {
/* Translate value in seconds to number of retransmits */
while (val > ((TCP_TIMEOUT_INIT/HZ)<<tp->defer_accept))
tp->defer_accept++;
tp->defer_accept++;
}
break;
case TCP_WINDOW_CLAMP:
if (val==0) {
if (sk->state != TCP_CLOSE) {
err = -EINVAL;
break;
}
tp->window_clamp = 0;
} else {
tp->window_clamp = val<SOCK_MIN_RCVBUF/2 ?
SOCK_MIN_RCVBUF/2 : val;
}
break;
default:
err = -ENOPROTOOPT;
break;
};
release_sock(sk);
return err;
}
int tcp_getsockopt(struct sock *sk, int level, int optname, char *optval,
int *optlen)
{
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
int val, len;
if(level != SOL_TCP)
return tp->af_specific->getsockopt(sk, level, optname,
optval, optlen);
if(get_user(len,optlen))
return -EFAULT;
len = min(len, sizeof(int));
switch(optname) {
case TCP_MAXSEG:
val = tp->mss_cache;
if (val == 0 && ((1<<sk->state)&(TCPF_CLOSE|TCPF_LISTEN)))
val = tp->user_mss;
break;
case TCP_NODELAY:
val = (tp->nonagle == 1);
break;
case TCP_CORK:
val = (tp->nonagle == 2);
break;
case TCP_KEEPIDLE:
val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time)/HZ;
break;
case TCP_KEEPINTVL:
val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl)/HZ;
break;
case TCP_KEEPCNT:
val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
break;
case TCP_SYNCNT:
val = tp->syn_retries ? : sysctl_tcp_syn_retries;
break;
case TCP_LINGER2:
val = tp->linger2;
if (val > 0)
val = (val ? : sysctl_tcp_fin_timeout)/HZ;
break;
case TCP_DEFER_ACCEPT:
val = tp->defer_accept == 0 ? 0 : (TCP_TIMEOUT_INIT<<(tp->defer_accept-1));
break;
case TCP_WINDOW_CLAMP:
val = tp->window_clamp;
break;
case TCP_INFO:
{
struct tcp_info info;
u32 now = tcp_time_stamp;
if(get_user(len,optlen))
return -EFAULT;
info.tcpi_state = sk->state;
info.tcpi_ca_state = tp->ca_state;
info.tcpi_retransmits = tp->retransmits;
info.tcpi_probes = tp->probes_out;
info.tcpi_backoff = tp->backoff;
info.tcpi_options = 0;
if (tp->tstamp_ok)
info.tcpi_options |= TCPI_OPT_TIMESTAMPS;
if (tp->sack_ok)
info.tcpi_options |= TCPI_OPT_SACK;
if (tp->wscale_ok) {
info.tcpi_options |= TCPI_OPT_WSCALE;
info.tcpi_snd_wscale = tp->snd_wscale;
info.tcpi_rcv_wscale = tp->rcv_wscale;
} else {
info.tcpi_snd_wscale = 0;
info.tcpi_rcv_wscale = 0;
}
#ifdef CONFIG_INET_ECN
if (tp->ecn_flags&TCP_ECN_OK)
info.tcpi_options |= TCPI_OPT_ECN;
#endif
info.tcpi_rto = (1000000*tp->rto)/HZ;
info.tcpi_ato = (1000000*tp->ack.ato)/HZ;
info.tcpi_snd_mss = tp->mss_cache;
info.tcpi_rcv_mss = tp->ack.rcv_mss;
info.tcpi_unacked = tp->packets_out;
info.tcpi_sacked = tp->sacked_out;
info.tcpi_lost = tp->lost_out;
info.tcpi_retrans = tp->retrans_out;
info.tcpi_fackets = tp->fackets_out;
info.tcpi_last_data_sent = ((now - tp->lsndtime)*1000)/HZ;
info.tcpi_last_ack_sent = 0;
info.tcpi_last_data_recv = ((now - tp->ack.lrcvtime)*1000)/HZ;
info.tcpi_last_ack_recv = ((now - tp->rcv_tstamp)*1000)/HZ;
info.tcpi_pmtu = tp->pmtu_cookie;
info.tcpi_rcv_ssthresh = tp->rcv_ssthresh;
info.tcpi_rtt = ((1000000*tp->srtt)/HZ)>>3;
info.tcpi_rttvar = ((1000000*tp->mdev)/HZ)>>2;
info.tcpi_snd_ssthresh = tp->snd_ssthresh;
info.tcpi_snd_cwnd = tp->snd_cwnd;
info.tcpi_advmss = tp->advmss;
info.tcpi_reordering = tp->reordering;
len = min(len, sizeof(info));
if(put_user(len, optlen))
return -EFAULT;
if(copy_to_user(optval, &info,len))
return -EFAULT;
return 0;
}
default:
return -ENOPROTOOPT;
};
if(put_user(len, optlen))
return -EFAULT;
if(copy_to_user(optval, &val,len))
return -EFAULT;
return 0;
}
extern void __skb_cb_too_small_for_tcp(int, int);
void __init tcp_init(void)
{
struct sk_buff *skb = NULL;
unsigned long goal;
int order, i;
if(sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
__skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
sizeof(skb->cb));
tcp_openreq_cachep = kmem_cache_create("tcp_open_request",
sizeof(struct open_request),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if(!tcp_openreq_cachep)
panic("tcp_init: Cannot alloc open_request cache.");
tcp_bucket_cachep = kmem_cache_create("tcp_bind_bucket",
sizeof(struct tcp_bind_bucket),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if(!tcp_bucket_cachep)
panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
sizeof(struct tcp_tw_bucket),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if(!tcp_timewait_cachep)
panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
/* Size and allocate the main established and bind bucket
* hash tables.
*
* The methodology is similar to that of the buffer cache.
*/
goal = num_physpages >> (23 - PAGE_SHIFT);
for(order = 0; (1UL << order) < goal; order++)
;
do {
tcp_ehash_size = (1UL << order) * PAGE_SIZE /
sizeof(struct tcp_ehash_bucket);
tcp_ehash_size >>= 1;
while (tcp_ehash_size & (tcp_ehash_size-1))
tcp_ehash_size--;
tcp_ehash = (struct tcp_ehash_bucket *)
__get_free_pages(GFP_ATOMIC, order);
} while (tcp_ehash == NULL && --order > 0);
if (!tcp_ehash)
panic("Failed to allocate TCP established hash table\n");
for (i = 0; i < (tcp_ehash_size<<1); i++) {
tcp_ehash[i].lock = RW_LOCK_UNLOCKED;
tcp_ehash[i].chain = NULL;
}
do {
tcp_bhash_size = (1UL << order) * PAGE_SIZE /
sizeof(struct tcp_bind_hashbucket);
if ((tcp_bhash_size > (64 * 1024)) && order > 0)
continue;
tcp_bhash = (struct tcp_bind_hashbucket *)
__get_free_pages(GFP_ATOMIC, order);
} while (tcp_bhash == NULL && --order >= 0);
if (!tcp_bhash)
panic("Failed to allocate TCP bind hash table\n");
for (i = 0; i < tcp_bhash_size; i++) {
tcp_bhash[i].lock = SPIN_LOCK_UNLOCKED;
tcp_bhash[i].chain = NULL;
}
/* Try to be a bit smarter and adjust defaults depending
* on available memory.
*/
if (order > 4) {
sysctl_local_port_range[0] = 32768;
sysctl_local_port_range[1] = 61000;
sysctl_tcp_max_tw_buckets = 180000;
sysctl_tcp_max_orphans = 4096<<(order-4);
sysctl_max_syn_backlog = 1024;
} else if (order < 3) {
sysctl_local_port_range[0] = 1024*(3-order);
sysctl_tcp_max_tw_buckets >>= (3-order);
sysctl_tcp_max_orphans >>= (3-order);
sysctl_max_syn_backlog = 128;
}
tcp_port_rover = sysctl_local_port_range[0] - 1;
sysctl_tcp_mem[0] = 64<<order;
sysctl_tcp_mem[1] = 200<<order;
sysctl_tcp_mem[2] = 256<<order;
if (sysctl_tcp_mem[2] - sysctl_tcp_mem[1] > 512)
sysctl_tcp_mem[1] = sysctl_tcp_mem[2] - 512;
if (sysctl_tcp_mem[1] - sysctl_tcp_mem[0] > 512)
sysctl_tcp_mem[0] = sysctl_tcp_mem[1] - 512;
if (order < 3) {
sysctl_tcp_wmem[2] = 64*1024;
sysctl_tcp_rmem[0] = PAGE_SIZE;
sysctl_tcp_rmem[1] = 43689;
sysctl_tcp_rmem[2] = 2*43689;
}
printk("TCP: Hash tables configured (established %d bind %d)\n",
tcp_ehash_size<<1, tcp_bhash_size);
}