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gerrit-public.fairphone.software / kernel / msm-4.9 / de0744af1fe2d0a3d428f6af0f2fe1f6179b1a9c / . / net / ipv4 / tcp.c
blob: 9e0e45c378061a17fa6a5bcecd729322c1e8bcbe [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).
*
* Authors: Ross Biro
* 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 it's 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)
* Hirokazu Takahashi : Use copy_from_user() instead of
* csum_and_copy_from_user() if possible.
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/skbuff.h>
#include <linux/scatterlist.h>
#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/random.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/crypto.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/netdma.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
atomic_t tcp_orphan_count = ATOMIC_INIT(0);
EXPORT_SYMBOL_GPL(tcp_orphan_count);
int sysctl_tcp_mem[3] __read_mostly;
int sysctl_tcp_wmem[3] __read_mostly;
int sysctl_tcp_rmem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_tcp_mem);
EXPORT_SYMBOL(sysctl_tcp_rmem);
EXPORT_SYMBOL(sysctl_tcp_wmem);
atomic_t tcp_memory_allocated; /* Current allocated memory. */
atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
EXPORT_SYMBOL(tcp_memory_allocated);
EXPORT_SYMBOL(tcp_sockets_allocated);
/*
* TCP splice context
*/
struct tcp_splice_state {
struct pipe_inode_info *pipe;
size_t len;
unsigned int flags;
};
/*
* Pressure flag: try to collapse.
* Technical note: it is used by multiple contexts non atomically.
* All the __sk_mem_schedule() is of this nature: accounting
* is strict, actions are advisory and have some latency.
*/
int tcp_memory_pressure __read_mostly;
EXPORT_SYMBOL(tcp_memory_pressure);
void tcp_enter_memory_pressure(struct sock *sk)
{
if (!tcp_memory_pressure) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
tcp_memory_pressure = 1;
}
}
EXPORT_SYMBOL(tcp_enter_memory_pressure);
/*
* 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_sock *tp = tcp_sk(sk);
poll_wait(file, sk->sk_sleep, wait);
if (sk->sk_state == TCP_LISTEN)
return inet_csk_listen_poll(sk);
/* Socket is not locked. We are protected from async events
* by poll logic and correct handling of state changes
* made by other threads is impossible in any case.
*/
mask = 0;
if (sk->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 POLLHUP were maskable,
* then we could set it on SND_SHUTDOWN. BTW examples given
* in Stevens' books assume exactly this behaviour, it explains
* why POLLHUP 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->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
mask |= POLLHUP;
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= POLLIN | POLLRDNORM | POLLRDHUP;
/* Connected? */
if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
/* Potential race condition. If read of tp below will
* escape above sk->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 ||
sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
mask |= POLLIN | POLLRDNORM;
if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
mask |= POLLOUT | POLLWRNORM;
} else { /* send SIGIO later */
set_bit(SOCK_ASYNC_NOSPACE,
&sk->sk_socket->flags);
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
/* Race breaker. If space is freed after
* wspace test but before the flags are set,
* IO signal will be lost.
*/
if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
mask |= POLLOUT | POLLWRNORM;
}
}
if (tp->urg_data & TCP_URG_VALID)
mask |= POLLPRI;
}
return mask;
}
int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
struct tcp_sock *tp = tcp_sk(sk);
int answ;
switch (cmd) {
case SIOCINQ:
if (sk->sk_state == TCP_LISTEN)
return -EINVAL;
lock_sock(sk);
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
answ = 0;
else if (sock_flag(sk, SOCK_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->sk_receive_queue))
answ -=
tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->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->sk_state == TCP_LISTEN)
return -EINVAL;
if ((1 << sk->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 __user *)arg);
}
static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
tp->pushed_seq = tp->write_seq;
}
static inline int forced_push(struct tcp_sock *tp)
{
return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}
static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
skb->csum = 0;
tcb->seq = tcb->end_seq = tp->write_seq;
tcb->flags = TCPCB_FLAG_ACK;
tcb->sacked = 0;
skb_header_release(skb);
tcp_add_write_queue_tail(sk, skb);
sk->sk_wmem_queued += skb->truesize;
sk_mem_charge(sk, skb->truesize);
if (tp->nonagle & TCP_NAGLE_PUSH)
tp->nonagle &= ~TCP_NAGLE_PUSH;
}
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
struct sk_buff *skb)
{
if (flags & MSG_OOB) {
tp->urg_mode = 1;
tp->snd_up = tp->write_seq;
}
}
static inline void tcp_push(struct sock *sk, int flags, int mss_now,
int nonagle)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_send_head(sk)) {
struct sk_buff *skb = tcp_write_queue_tail(sk);
if (!(flags & MSG_MORE) || forced_push(tp))
tcp_mark_push(tp, skb);
tcp_mark_urg(tp, flags, skb);
__tcp_push_pending_frames(sk, mss_now,
(flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
}
}
static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
unsigned int offset, size_t len)
{
struct tcp_splice_state *tss = rd_desc->arg.data;
return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags);
}
static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
{
/* Store TCP splice context information in read_descriptor_t. */
read_descriptor_t rd_desc = {
.arg.data = tss,
};
return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
}
/**
* tcp_splice_read - splice data from TCP socket to a pipe
* @sock: socket to splice from
* @ppos: position (not valid)
* @pipe: pipe to splice to
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* Will read pages from given socket and fill them into a pipe.
*
**/
ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct sock *sk = sock->sk;
struct tcp_splice_state tss = {
.pipe = pipe,
.len = len,
.flags = flags,
};
long timeo;
ssize_t spliced;
int ret;
/*
* We can't seek on a socket input
*/
if (unlikely(*ppos))
return -ESPIPE;
ret = spliced = 0;
lock_sock(sk);
timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
while (tss.len) {
ret = __tcp_splice_read(sk, &tss);
if (ret < 0)
break;
else if (!ret) {
if (spliced)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
ret = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
/*
* This occurs when user tries to read
* from never connected socket.
*/
if (!sock_flag(sk, SOCK_DONE))
ret = -ENOTCONN;
break;
}
if (!timeo) {
ret = -EAGAIN;
break;
}
sk_wait_data(sk, &timeo);
if (signal_pending(current)) {
ret = sock_intr_errno(timeo);
break;
}
continue;
}
tss.len -= ret;
spliced += ret;
release_sock(sk);
lock_sock(sk);
if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||
signal_pending(current))
break;
}
release_sock(sk);
if (spliced)
return spliced;
return ret;
}
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
{
struct sk_buff *skb;
/* The TCP header must be at least 32-bit aligned. */
size = ALIGN(size, 4);
skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
if (skb) {
if (sk_wmem_schedule(sk, skb->truesize)) {
/*
* Make sure that we have exactly size bytes
* available to the caller, no more, no less.
*/
skb_reserve(skb, skb_tailroom(skb) - size);
return skb;
}
__kfree_skb(skb);
} else {
sk->sk_prot->enter_memory_pressure(sk);
sk_stream_moderate_sndbuf(sk);
}
return NULL;
}
static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
size_t psize, int flags)
{
struct tcp_sock *tp = tcp_sk(sk);
int mss_now, size_goal;
int err;
ssize_t copied;
long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
/* Wait for a connection to finish. */
if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
goto out_err;
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
size_goal = tp->xmit_size_goal;
copied = 0;
err = -EPIPE;
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
goto do_error;
while (psize > 0) {
struct sk_buff *skb = tcp_write_queue_tail(sk);
struct page *page = pages[poffset / PAGE_SIZE];
int copy, i, can_coalesce;
int offset = poffset % PAGE_SIZE;
int size = min_t(size_t, psize, PAGE_SIZE - offset);
if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
new_segment:
if (!sk_stream_memory_free(sk))
goto wait_for_sndbuf;
skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
if (!skb)
goto wait_for_memory;
skb_entail(sk, skb);
copy = size_goal;
}
if (copy > size)
copy = size;
i = skb_shinfo(skb)->nr_frags;
can_coalesce = skb_can_coalesce(skb, i, page, offset);
if (!can_coalesce && i >= MAX_SKB_FRAGS) {
tcp_mark_push(tp, skb);
goto new_segment;
}
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
if (can_coalesce) {
skb_shinfo(skb)->frags[i - 1].size += copy;
} else {
get_page(page);
skb_fill_page_desc(skb, i, page, offset, copy);
}
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
sk->sk_wmem_queued += copy;
sk_mem_charge(sk, copy);
skb->ip_summed = CHECKSUM_PARTIAL;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
skb_shinfo(skb)->gso_segs = 0;
if (!copied)
TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
copied += copy;
poffset += copy;
if (!(psize -= copy))
goto out;
if (skb->len < size_goal || (flags & MSG_OOB))
continue;
if (forced_push(tp)) {
tcp_mark_push(tp, skb);
__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
} else if (skb == tcp_send_head(sk))
tcp_push_one(sk, mss_now);
continue;
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
if (copied)
tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
goto do_error;
mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
size_goal = tp->xmit_size_goal;
}
out:
if (copied)
tcp_push(sk, flags, mss_now, tp->nonagle);
return copied;
do_error:
if (copied)
goto out;
out_err:
return sk_stream_error(sk, flags, 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;
if (!(sk->sk_route_caps & NETIF_F_SG) ||
!(sk->sk_route_caps & NETIF_F_ALL_CSUM))
return sock_no_sendpage(sock, page, offset, size, flags);
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->sk_sndmsg_page)
#define TCP_OFF(sk) (sk->sk_sndmsg_off)
static inline int select_size(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
int tmp = tp->mss_cache;
if (sk->sk_route_caps & NETIF_F_SG) {
if (sk_can_gso(sk))
tmp = 0;
else {
int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
if (tmp >= pgbreak &&
tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
tmp = pgbreak;
}
}
return tmp;
}
int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
size_t size)
{
struct sock *sk = sock->sk;
struct iovec *iov;
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
int iovlen, flags;
int mss_now, size_goal;
int err, copied;
long timeo;
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->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
goto out_err;
/* This should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
size_goal = tp->xmit_size_goal;
/* Ok commence sending. */
iovlen = msg->msg_iovlen;
iov = msg->msg_iov;
copied = 0;
err = -EPIPE;
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
goto do_error;
while (--iovlen >= 0) {
int seglen = iov->iov_len;
unsigned char __user *from = iov->iov_base;
iov++;
while (seglen > 0) {
int copy;
skb = tcp_write_queue_tail(sk);
if (!tcp_send_head(sk) ||
(copy = size_goal - skb->len) <= 0) {
new_segment:
/* Allocate new segment. If the interface is SG,
* allocate skb fitting to single page.
*/
if (!sk_stream_memory_free(sk))
goto wait_for_sndbuf;
skb = sk_stream_alloc_skb(sk, select_size(sk),
sk->sk_allocation);
if (!skb)
goto wait_for_memory;
/*
* Check whether we can use HW checksum.
*/
if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
skb->ip_summed = CHECKSUM_PARTIAL;
skb_entail(sk, skb);
copy = size_goal;
}
/* Try to append data to the end of skb. */
if (copy > seglen)
copy = seglen;
/* Where to copy to? */
if (skb_tailroom(skb) > 0) {
/* We have some space in skb head. Superb! */
if (copy > skb_tailroom(skb))
copy = skb_tailroom(skb);
if ((err = skb_add_data(skb, from, copy)) != 0)
goto do_fault;
} else {
int merge = 0;
int i = skb_shinfo(skb)->nr_frags;
struct page *page = TCP_PAGE(sk);
int off = TCP_OFF(sk);
if (skb_can_coalesce(skb, i, page, off) &&
off != PAGE_SIZE) {
/* We can extend the last page
* fragment. */
merge = 1;
} else if (i == MAX_SKB_FRAGS ||
(!i &&
!(sk->sk_route_caps & NETIF_F_SG))) {
/* Need to add new fragment and cannot
* do this because interface is non-SG,
* or because all the page slots are
* busy. */
tcp_mark_push(tp, skb);
goto new_segment;
} else if (page) {
if (off == PAGE_SIZE) {
put_page(page);
TCP_PAGE(sk) = page = NULL;
off = 0;
}
} else
off = 0;
if (copy > PAGE_SIZE - off)
copy = PAGE_SIZE - off;
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
if (!page) {
/* Allocate new cache page. */
if (!(page = sk_stream_alloc_page(sk)))
goto wait_for_memory;
}
/* Time to copy data. We are close to
* the end! */
err = skb_copy_to_page(sk, from, skb, page,
off, copy);
if (err) {
/* If this page was new, give it to the
* socket so it does not get leaked.
*/
if (!TCP_PAGE(sk)) {
TCP_PAGE(sk) = page;
TCP_OFF(sk) = 0;
}
goto do_error;
}
/* Update the skb. */
if (merge) {
skb_shinfo(skb)->frags[i - 1].size +=
copy;
} else {
skb_fill_page_desc(skb, i, page, off, copy);
if (TCP_PAGE(sk)) {
get_page(page);
} else if (off + copy < PAGE_SIZE) {
get_page(page);
TCP_PAGE(sk) = page;
}
}
TCP_OFF(sk) = off + copy;
}
if (!copied)
TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
skb_shinfo(skb)->gso_segs = 0;
from += copy;
copied += copy;
if ((seglen -= copy) == 0 && iovlen == 0)
goto out;
if (skb->len < size_goal || (flags & MSG_OOB))
continue;
if (forced_push(tp)) {
tcp_mark_push(tp, skb);
__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
} else if (skb == tcp_send_head(sk))
tcp_push_one(sk, mss_now);
continue;
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
if (copied)
tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
goto do_error;
mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
size_goal = tp->xmit_size_goal;
}
}
out:
if (copied)
tcp_push(sk, flags, mss_now, tp->nonagle);
TCP_CHECK_TIMER(sk);
release_sock(sk);
return copied;
do_fault:
if (!skb->len) {
tcp_unlink_write_queue(skb, sk);
/* It is the one place in all of TCP, except connection
* reset, where we can be unlinking the send_head.
*/
tcp_check_send_head(sk, skb);
sk_wmem_free_skb(sk, skb);
}
do_error:
if (copied)
goto out;
out_err:
err = sk_stream_error(sk, flags, err);
TCP_CHECK_TIMER(sk);
release_sock(sk);
return err;
}
/*
* 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_sock *tp = tcp_sk(sk);
/* No URG data to read. */
if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
tp->urg_data == TCP_URG_READ)
return -EINVAL; /* Yes this is right ! */
if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_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_TRUNC))
err = memcpy_toiovec(msg->msg_iov, &c, 1);
len = 1;
} else
msg->msg_flags |= MSG_TRUNC;
return err ? -EFAULT : len;
}
if (sk->sk_state == TCP_CLOSE || (sk->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;
}
/* 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.
*/
void tcp_cleanup_rbuf(struct sock *sk, int copied)
{
struct tcp_sock *tp = tcp_sk(sk);
int time_to_ack = 0;
#if TCP_DEBUG
struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
#endif
if (inet_csk_ack_scheduled(sk)) {
const struct inet_connection_sock *icsk = inet_csk(sk);
/* Delayed ACKs frequently hit locked sockets during bulk
* receive. */
if (icsk->icsk_ack.blocked ||
/* Once-per-two-segments ACK was not sent by tcp_input.c */
tp->rcv_nxt - tp->rcv_wup > icsk->icsk_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 &&
((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
!icsk->icsk_ack.pingpong)) &&
!atomic_read(&sk->sk_rmem_alloc)))
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->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);
}
static void tcp_prequeue_process(struct sock *sk)
{
struct sk_buff *skb;
struct tcp_sock *tp = tcp_sk(sk);
NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
/* 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->sk_backlog_rcv(sk, skb);
local_bh_enable();
/* Clear memory counter. */
tp->ucopy.memory = 0;
}
static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
{
struct sk_buff *skb;
u32 offset;
skb_queue_walk(&sk->sk_receive_queue, skb) {
offset = seq - TCP_SKB_CB(skb)->seq;
if (tcp_hdr(skb)->syn)
offset--;
if (offset < skb->len || tcp_hdr(skb)->fin) {
*off = offset;
return skb;
}
}
return NULL;
}
/*
* This routine provides an alternative to tcp_recvmsg() for routines
* that would like to handle copying from skbuffs directly in 'sendfile'
* fashion.
* Note:
* - It is assumed that the socket was locked by the caller.
* - The routine does not block.
* - At present, there is no support for reading OOB data
* or for 'peeking' the socket using this routine
* (although both would be easy to implement).
*/
int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
sk_read_actor_t recv_actor)
{
struct sk_buff *skb;
struct tcp_sock *tp = tcp_sk(sk);
u32 seq = tp->copied_seq;
u32 offset;
int copied = 0;
if (sk->sk_state == TCP_LISTEN)
return -ENOTCONN;
while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
if (offset < skb->len) {
int used;
size_t len;
len = skb->len - offset;
/* Stop reading if we hit a patch of urgent data */
if (tp->urg_data) {
u32 urg_offset = tp->urg_seq - seq;
if (urg_offset < len)
len = urg_offset;
if (!len)
break;
}
used = recv_actor(desc, skb, offset, len);
if (used < 0) {
if (!copied)
copied = used;
break;
} else if (used <= len) {
seq += used;
copied += used;
offset += used;
}
/*
* If recv_actor drops the lock (e.g. TCP splice
* receive) the skb pointer might be invalid when
* getting here: tcp_collapse might have deleted it
* while aggregating skbs from the socket queue.
*/
skb = tcp_recv_skb(sk, seq-1, &offset);
if (!skb || (offset+1 != skb->len))
break;
}
if (tcp_hdr(skb)->fin) {
sk_eat_skb(sk, skb, 0);
++seq;
break;
}
sk_eat_skb(sk, skb, 0);
if (!desc->count)
break;
}
tp->copied_seq = seq;
tcp_rcv_space_adjust(sk);
/* Clean up data we have read: This will do ACK frames. */
if (copied > 0)
tcp_cleanup_rbuf(sk, copied);
return copied;
}
/*
* 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 kiocb *iocb, struct sock *sk, struct msghdr *msg,
size_t len, int nonblock, int flags, int *addr_len)
{
struct tcp_sock *tp = tcp_sk(sk);
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;
int copied_early = 0;
struct sk_buff *skb;
lock_sock(sk);
TCP_CHECK_TIMER(sk);
err = -ENOTCONN;
if (sk->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);
#ifdef CONFIG_NET_DMA
tp->ucopy.dma_chan = NULL;
preempt_disable();
skb = skb_peek_tail(&sk->sk_receive_queue);
{
int available = 0;
if (skb)
available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
if ((available < target) &&
(len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
!sysctl_tcp_low_latency &&
__get_cpu_var(softnet_data).net_dma) {
preempt_enable_no_resched();
tp->ucopy.pinned_list =
dma_pin_iovec_pages(msg->msg_iov, len);
} else {
preempt_enable_no_resched();
}
}
#endif
do {
u32 offset;
/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
if (tp->urg_data && tp->urg_seq == *seq) {
if (copied)
break;
if (signal_pending(current)) {
copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
break;
}
}
/* Next get a buffer. */
skb = skb_peek(&sk->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 (tcp_hdr(skb)->syn)
offset--;
if (offset < skb->len)
goto found_ok_skb;
if (tcp_hdr(skb)->fin)
goto found_fin_ok;
BUG_TRAP(flags & MSG_PEEK);
skb = skb->next;
} while (skb != (struct sk_buff *)&sk->sk_receive_queue);
/* Well, if we have backlog, try to process it now yet. */
if (copied >= target && !sk->sk_backlog.tail)
break;
if (copied) {
if (sk->sk_err ||
sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
!timeo ||
signal_pending(current) ||
(flags & MSG_PEEK))
break;
} else {
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
copied = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
if (!sock_flag(sk, SOCK_DONE)) {
/* This occurs when user tries to read
* from never connected socket.
*/
copied = -ENOTCONN;
break;
}
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
if (signal_pending(current)) {
copied = sock_intr_errno(timeo);
break;
}
}
tcp_cleanup_rbuf(sk, copied);
if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
/* Install new reader */
if (!user_recv && !(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 2nd 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_empty(&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
sk_wait_data(sk, &timeo);
#ifdef CONFIG_NET_DMA
tp->ucopy.wakeup = 0;
#endif
if (user_recv) {
int chunk;
/* __ Restore normal policy in scheduler __ */
if ((chunk = len - tp->ucopy.len) != 0) {
NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
len -= chunk;
copied += chunk;
}
if (tp->rcv_nxt == tp->copied_seq &&
!skb_queue_empty(&tp->ucopy.prequeue)) {
do_prequeue:
tcp_prequeue_process(sk);
if ((chunk = len - tp->ucopy.len) != 0) {
NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
len -= chunk;
copied += chunk;
}
}
}
if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
if (net_ratelimit())
printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
current->comm, task_pid_nr(current));
peek_seq = tp->copied_seq;
}
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 (!sock_flag(sk, SOCK_URGINLINE)) {
++*seq;
offset++;
used--;
if (!used)
goto skip_copy;
}
} else
used = urg_offset;
}
}
if (!(flags & MSG_TRUNC)) {
#ifdef CONFIG_NET_DMA
if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
tp->ucopy.dma_chan = get_softnet_dma();
if (tp->ucopy.dma_chan) {
tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
tp->ucopy.dma_chan, skb, offset,
msg->msg_iov, used,
tp->ucopy.pinned_list);
if (tp->ucopy.dma_cookie < 0) {
printk(KERN_ALERT "dma_cookie < 0\n");
/* Exception. Bailout! */
if (!copied)
copied = -EFAULT;
break;
}
if ((offset + used) == skb->len)
copied_early = 1;
} else
#endif
{
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;
tcp_rcv_space_adjust(sk);
skip_copy:
if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
tp->urg_data = 0;
tcp_fast_path_check(sk);
}
if (used + offset < skb->len)
continue;
if (tcp_hdr(skb)->fin)
goto found_fin_ok;
if (!(flags & MSG_PEEK)) {
sk_eat_skb(sk, skb, copied_early);
copied_early = 0;
}
continue;
found_fin_ok:
/* Process the FIN. */
++*seq;
if (!(flags & MSG_PEEK)) {
sk_eat_skb(sk, skb, copied_early);
copied_early = 0;
}
break;
} while (len > 0);
if (user_recv) {
if (!skb_queue_empty(&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_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
len -= chunk;
copied += chunk;
}
}
tp->ucopy.task = NULL;
tp->ucopy.len = 0;
}
#ifdef CONFIG_NET_DMA
if (tp->ucopy.dma_chan) {
dma_cookie_t done, used;
dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
tp->ucopy.dma_cookie, &done,
&used) == DMA_IN_PROGRESS) {
/* do partial cleanup of sk_async_wait_queue */
while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
(dma_async_is_complete(skb->dma_cookie, done,
used) == DMA_SUCCESS)) {
__skb_dequeue(&sk->sk_async_wait_queue);
kfree_skb(skb);
}
}
/* Safe to free early-copied skbs now */
__skb_queue_purge(&sk->sk_async_wait_queue);
dma_chan_put(tp->ucopy.dma_chan);
tp->ucopy.dma_chan = NULL;
}
if (tp->ucopy.pinned_list) {
dma_unpin_iovec_pages(tp->ucopy.pinned_list);
tp->ucopy.pinned_list = NULL;
}
#endif
/* 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. */
tcp_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;
}
void tcp_set_state(struct sock *sk, int state)
{
int oldstate = sk->sk_state;
switch (state) {
case TCP_ESTABLISHED:
if (oldstate != TCP_ESTABLISHED)
TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
break;
case TCP_CLOSE:
if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
sk->sk_prot->unhash(sk);
if (inet_csk(sk)->icsk_bind_hash &&
!(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
inet_put_port(sk);
/* fall through */
default:
if (oldstate==TCP_ESTABLISHED)
TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
}
/* Change state AFTER socket is unhashed to avoid closed
* socket sitting in hash tables.
*/
sk->sk_state = state;
#ifdef STATE_TRACE
SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);
/*
* 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 const 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->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 sock_set_flag(sk, SOCK_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->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);
}
}
void tcp_close(struct sock *sk, long timeout)
{
struct sk_buff *skb;
int data_was_unread = 0;
int state;
lock_sock(sk);
sk->sk_shutdown = SHUTDOWN_MASK;
if (sk->sk_state == TCP_LISTEN) {
tcp_set_state(sk, TCP_CLOSE);
/* Special case. */
inet_csk_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->sk_receive_queue)) != NULL) {
u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
tcp_hdr(skb)->fin;
data_was_unread += len;
__kfree_skb(skb);
}
sk_mem_reclaim(sk);
/* As outlined in RFC 2525, section 2.17, 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) {
/* Unread data was tossed, zap the connection. */
NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_KERNEL);
} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
/* Check zero linger _after_ checking for unread data. */
sk->sk_prot->disconnect(sk, 0);
NET_INC_STATS_USER(LINUX_MIB_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);
}
sk_stream_wait_close(sk, timeout);
adjudge_to_death:
state = sk->sk_state;
sock_hold(sk);
sock_orphan(sk);
atomic_inc(sk->sk_prot->orphan_count);
/* 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(!sock_owned_by_user(sk));
/* Have we already been destroyed by a softirq or backlog? */
if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
goto out;
/* 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->sk_state == TCP_FIN_WAIT2) {
struct tcp_sock *tp = tcp_sk(sk);
if (tp->linger2 < 0) {
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
NET_INC_STATS_BH(sock_net(sk),
LINUX_MIB_TCPABORTONLINGER);
} else {
const int tmo = tcp_fin_time(sk);
if (tmo > TCP_TIMEWAIT_LEN) {
inet_csk_reset_keepalive_timer(sk,
tmo - TCP_TIMEWAIT_LEN);
} else {
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
goto out;
}
}
}
if (sk->sk_state != TCP_CLOSE) {
sk_mem_reclaim(sk);
if (tcp_too_many_orphans(sk,
atomic_read(sk->sk_prot->orphan_count))) {
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(sock_net(sk),
LINUX_MIB_TCPABORTONMEMORY);
}
}
if (sk->sk_state == TCP_CLOSE)
inet_csk_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 */
static 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 inet_sock *inet = inet_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
int err = 0;
int old_state = sk->sk_state;
if (old_state != TCP_CLOSE)
tcp_set_state(sk, TCP_CLOSE);
/* ABORT function of RFC793 */
if (old_state == TCP_LISTEN) {
inet_csk_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 discrepancy of Linux wrt. RFC
* states
*/
tcp_send_active_reset(sk, gfp_any());
sk->sk_err = ECONNRESET;
} else if (old_state == TCP_SYN_SENT)
sk->sk_err = ECONNRESET;
tcp_clear_xmit_timers(sk);
__skb_queue_purge(&sk->sk_receive_queue);
tcp_write_queue_purge(sk);
__skb_queue_purge(&tp->out_of_order_queue);
#ifdef CONFIG_NET_DMA
__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
inet->dport = 0;
if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
inet_reset_saddr(sk);
sk->sk_shutdown = 0;
sock_reset_flag(sk, SOCK_DONE);
tp->srtt = 0;
if ((tp->write_seq += tp->max_window + 2) == 0)
tp->write_seq = 1;
icsk->icsk_backoff = 0;
tp->snd_cwnd = 2;
icsk->icsk_probes_out = 0;
tp->packets_out = 0;
tp->snd_ssthresh = 0x7fffffff;
tp->snd_cwnd_cnt = 0;
tp->bytes_acked = 0;
tcp_set_ca_state(sk, TCP_CA_Open);
tcp_clear_retrans(tp);
inet_csk_delack_init(sk);
tcp_init_send_head(sk);
memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
__sk_dst_reset(sk);
BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
sk->sk_error_report(sk);
return err;
}
/*
* Socket option code for TCP.
*/
static int do_tcp_setsockopt(struct sock *sk, int level,
int optname, char __user *optval, int optlen)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
int val;
int err = 0;
/* This is a string value all the others are int's */
if (optname == TCP_CONGESTION) {
char name[TCP_CA_NAME_MAX];
if (optlen < 1)
return -EINVAL;
val = strncpy_from_user(name, optval,
min(TCP_CA_NAME_MAX-1, optlen));
if (val < 0)
return -EFAULT;
name[val] = 0;
lock_sock(sk);
err = tcp_set_congestion_control(sk, name);
release_sock(sk);
return err;
}
if (optlen < sizeof(int))
return -EINVAL;
if (get_user(val, (int __user *)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->rx_opt.user_mss = val;
break;
case TCP_NODELAY:
if (val) {
/* TCP_NODELAY is weaker than TCP_CORK, so that
* this option on corked socket is remembered, but
* it is not activated until cork is cleared.
*
* However, when TCP_NODELAY is set we make
* an explicit push, which overrides even TCP_CORK
* for currently queued segments.
*/
tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
tcp_push_pending_frames(sk);
} else {
tp->nonagle &= ~TCP_NAGLE_OFF;
}
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.
*
* TCP_CORK can be set together with TCP_NODELAY and it is
* stronger than TCP_NODELAY.
*/
if (val) {
tp->nonagle |= TCP_NAGLE_CORK;
} else {
tp->nonagle &= ~TCP_NAGLE_CORK;
if (tp->nonagle&TCP_NAGLE_OFF)
tp->nonagle |= TCP_NAGLE_PUSH;
tcp_push_pending_frames(sk);
}
break;
case TCP_KEEPIDLE:
if (val < 1 || val > MAX_TCP_KEEPIDLE)
err = -EINVAL;
else {
tp->keepalive_time = val * HZ;
if (sock_flag(sk, SOCK_KEEPOPEN) &&
!((1 << sk->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;
inet_csk_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
icsk->icsk_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:
icsk->icsk_accept_queue.rskq_defer_accept = 0;
if (val > 0) {
/* Translate value in seconds to number of
* retransmits */
while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
val > ((TCP_TIMEOUT_INIT / HZ) <<
icsk->icsk_accept_queue.rskq_defer_accept))
icsk->icsk_accept_queue.rskq_defer_accept++;
icsk->icsk_accept_queue.rskq_defer_accept++;
}
break;
case TCP_WINDOW_CLAMP:
if (!val) {
if (sk->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;
case TCP_QUICKACK:
if (!val) {
icsk->icsk_ack.pingpong = 1;
} else {
icsk->icsk_ack.pingpong = 0;
if ((1 << sk->sk_state) &
(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
inet_csk_ack_scheduled(sk)) {
icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
tcp_cleanup_rbuf(sk, 1);
if (!(val & 1))
icsk->icsk_ack.pingpong = 1;
}
}
break;
#ifdef CONFIG_TCP_MD5SIG
case TCP_MD5SIG:
/* Read the IP->Key mappings from userspace */
err = tp->af_specific->md5_parse(sk, optval, optlen);
break;
#endif
default:
err = -ENOPROTOOPT;
break;
}
release_sock(sk);
return err;
}
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
int optlen)
{
struct inet_connection_sock *icsk = inet_csk(sk);
if (level != SOL_TCP)
return icsk->icsk_af_ops->setsockopt(sk, level, optname,
optval, optlen);
return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen)
{
if (level != SOL_TCP)
return inet_csk_compat_setsockopt(sk, level, optname,
optval, optlen);
return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_tcp_setsockopt);
#endif
/* Return information about state of tcp endpoint in API format. */
void tcp_get_info(struct sock *sk, struct tcp_info *info)
{
struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
u32 now = tcp_time_stamp;
memset(info, 0, sizeof(*info));
info->tcpi_state = sk->sk_state;
info->tcpi_ca_state = icsk->icsk_ca_state;
info->tcpi_retransmits = icsk->icsk_retransmits;
info->tcpi_probes = icsk->icsk_probes_out;
info->tcpi_backoff = icsk->icsk_backoff;
if (tp->rx_opt.tstamp_ok)
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
if (tcp_is_sack(tp))
info->tcpi_options |= TCPI_OPT_SACK;
if (tp->rx_opt.wscale_ok) {
info->tcpi_options |= TCPI_OPT_WSCALE;
info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
}
if (tp->ecn_flags&TCP_ECN_OK)
info->tcpi_options |= TCPI_OPT_ECN;
info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
info->tcpi_snd_mss = tp->mss_cache;
info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
if (sk->sk_state == TCP_LISTEN) {
info->tcpi_unacked = sk->sk_ack_backlog;
info->tcpi_sacked = sk->sk_max_ack_backlog;
} else {
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 = jiffies_to_msecs(now - tp->lsndtime);
info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>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;
info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
info->tcpi_rcv_space = tp->rcvq_space.space;
info->tcpi_total_retrans = tp->total_retrans;
}
EXPORT_SYMBOL_GPL(tcp_get_info);
static int do_tcp_getsockopt(struct sock *sk, int level,
int optname, char __user *optval, int __user *optlen)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
int val, len;
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, sizeof(int));
if (len < 0)
return -EINVAL;
switch (optname) {
case TCP_MAXSEG:
val = tp->mss_cache;
if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
val = tp->rx_opt.user_mss;
break;
case TCP_NODELAY:
val = !!(tp->nonagle&TCP_NAGLE_OFF);
break;
case TCP_CORK:
val = !!(tp->nonagle&TCP_NAGLE_CORK);
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 = icsk->icsk_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 = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
break;
case TCP_WINDOW_CLAMP:
val = tp->window_clamp;
break;
case TCP_INFO: {
struct tcp_info info;
if (get_user(len, optlen))
return -EFAULT;
tcp_get_info(sk, &info);
len = min_t(unsigned int, len, sizeof(info));
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &info, len))
return -EFAULT;
return 0;
}
case TCP_QUICKACK:
val = !icsk->icsk_ack.pingpong;
break;
case TCP_CONGESTION:
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, icsk->icsk_ca_ops->name, 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;
}
int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
int __user *optlen)
{
struct inet_connection_sock *icsk = inet_csk(sk);
if (level != SOL_TCP)
return icsk->icsk_af_ops->getsockopt(sk, level, optname,
optval, optlen);
return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level != SOL_TCP)
return inet_csk_compat_getsockopt(sk, level, optname,
optval, optlen);
return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_tcp_getsockopt);
#endif
struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct tcphdr *th;
unsigned thlen;
unsigned int seq;
__be32 delta;
unsigned int oldlen;
unsigned int len;
if (!pskb_may_pull(skb, sizeof(*th)))
goto out;
th = tcp_hdr(skb);
thlen = th->doff * 4;
if (thlen < sizeof(*th))
goto out;
if (!pskb_may_pull(skb, thlen))
goto out;
oldlen = (u16)~skb->len;
__skb_pull(skb, thlen);
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
int mss;
if (unlikely(type &
~(SKB_GSO_TCPV4 |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCPV6 |
0) ||
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
goto out;
mss = skb_shinfo(skb)->gso_size;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
goto out;
}
segs = skb_segment(skb, features);
if (IS_ERR(segs))
goto out;
len = skb_shinfo(skb)->gso_size;
delta = htonl(oldlen + (thlen + len));
skb = segs;
th = tcp_hdr(skb);
seq = ntohl(th->seq);
do {
th->fin = th->psh = 0;
th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
if (skb->ip_summed != CHECKSUM_PARTIAL)
th->check =
csum_fold(csum_partial(skb_transport_header(skb),
thlen, skb->csum));
seq += len;
skb = skb->next;
th = tcp_hdr(skb);
th->seq = htonl(seq);
th->cwr = 0;
} while (skb->next);
delta = htonl(oldlen + (skb->tail - skb->transport_header) +
skb->data_len);
th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
if (skb->ip_summed != CHECKSUM_PARTIAL)
th->check = csum_fold(csum_partial(skb_transport_header(skb),
thlen, skb->csum));
out:
return segs;
}
EXPORT_SYMBOL(tcp_tso_segment);
#ifdef CONFIG_TCP_MD5SIG
static unsigned long tcp_md5sig_users;
static struct tcp_md5sig_pool **tcp_md5sig_pool;
static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
int tcp_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
int bplen,
struct tcphdr *th, unsigned int tcplen,
struct tcp_md5sig_pool *hp)
{
struct scatterlist sg[4];
__u16 data_len;
int block = 0;
__sum16 cksum;
struct hash_desc *desc = &hp->md5_desc;
int err;
unsigned int nbytes = 0;
sg_init_table(sg, 4);
/* 1. The TCP pseudo-header */
sg_set_buf(&sg[block++], &hp->md5_blk, bplen);
nbytes += bplen;
/* 2. The TCP header, excluding options, and assuming a
* checksum of zero
*/
cksum = th->check;
th->check = 0;
sg_set_buf(&sg[block++], th, sizeof(*th));
nbytes += sizeof(*th);
/* 3. The TCP segment data (if any) */
data_len = tcplen - (th->doff << 2);
if (data_len > 0) {
u8 *data = (u8 *)th + (th->doff << 2);
sg_set_buf(&sg[block++], data, data_len);
nbytes += data_len;
}
/* 4. an independently-specified key or password, known to both
* TCPs and presumably connection-specific
*/
sg_set_buf(&sg[block++], key->key, key->keylen);
nbytes += key->keylen;
sg_mark_end(&sg[block - 1]);
/* Now store the hash into the packet */
err = crypto_hash_init(desc);
if (err) {
if (net_ratelimit())
printk(KERN_WARNING "%s(): hash_init failed\n", __func__);
return -1;
}
err = crypto_hash_update(desc, sg, nbytes);
if (err) {
if (net_ratelimit())
printk(KERN_WARNING "%s(): hash_update failed\n", __func__);
return -1;
}
err = crypto_hash_final(desc, md5_hash);
if (err) {
if (net_ratelimit())
printk(KERN_WARNING "%s(): hash_final failed\n", __func__);
return -1;
}
/* Reset header */
th->check = cksum;
return 0;
}
EXPORT_SYMBOL(tcp_calc_md5_hash);
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
{
int cpu;
for_each_possible_cpu(cpu) {
struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
if (p) {
if (p->md5_desc.tfm)
crypto_free_hash(p->md5_desc.tfm);
kfree(p);
p = NULL;
}
}
free_percpu(pool);
}
void tcp_free_md5sig_pool(void)
{
struct tcp_md5sig_pool **pool = NULL;
spin_lock_bh(&tcp_md5sig_pool_lock);
if (--tcp_md5sig_users == 0) {
pool = tcp_md5sig_pool;
tcp_md5sig_pool = NULL;
}
spin_unlock_bh(&tcp_md5sig_pool_lock);
if (pool)
__tcp_free_md5sig_pool(pool);
}
EXPORT_SYMBOL(tcp_free_md5sig_pool);
static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
{
int cpu;
struct tcp_md5sig_pool **pool;
pool = alloc_percpu(struct tcp_md5sig_pool *);
if (!pool)
return NULL;
for_each_possible_cpu(cpu) {
struct tcp_md5sig_pool *p;
struct crypto_hash *hash;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
goto out_free;
*per_cpu_ptr(pool, cpu) = p;
hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
if (!hash || IS_ERR(hash))
goto out_free;
p->md5_desc.tfm = hash;
}
return pool;
out_free:
__tcp_free_md5sig_pool(pool);
return NULL;
}
struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
{
struct tcp_md5sig_pool **pool;
int alloc = 0;
retry:
spin_lock_bh(&tcp_md5sig_pool_lock);
pool = tcp_md5sig_pool;
if (tcp_md5sig_users++ == 0) {
alloc = 1;
spin_unlock_bh(&tcp_md5sig_pool_lock);
} else if (!pool) {
tcp_md5sig_users--;
spin_unlock_bh(&tcp_md5sig_pool_lock);
cpu_relax();
goto retry;
} else
spin_unlock_bh(&tcp_md5sig_pool_lock);
if (alloc) {
/* we cannot hold spinlock here because this may sleep. */
struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
spin_lock_bh(&tcp_md5sig_pool_lock);
if (!p) {
tcp_md5sig_users--;
spin_unlock_bh(&tcp_md5sig_pool_lock);
return NULL;
}
pool = tcp_md5sig_pool;
if (pool) {
/* oops, it has already been assigned. */
spin_unlock_bh(&tcp_md5sig_pool_lock);
__tcp_free_md5sig_pool(p);
} else {
tcp_md5sig_pool = pool = p;
spin_unlock_bh(&tcp_md5sig_pool_lock);
}
}
return pool;
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
{
struct tcp_md5sig_pool **p;
spin_lock_bh(&tcp_md5sig_pool_lock);
p = tcp_md5sig_pool;
if (p)
tcp_md5sig_users++;
spin_unlock_bh(&tcp_md5sig_pool_lock);
return (p ? *per_cpu_ptr(p, cpu) : NULL);
}
EXPORT_SYMBOL(__tcp_get_md5sig_pool);
void __tcp_put_md5sig_pool(void)
{
tcp_free_md5sig_pool();
}
EXPORT_SYMBOL(__tcp_put_md5sig_pool);
#endif
void tcp_done(struct sock *sk)
{
if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
tcp_set_state(sk, TCP_CLOSE);
tcp_clear_xmit_timers(sk);
sk->sk_shutdown = SHUTDOWN_MASK;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
else
inet_csk_destroy_sock(sk);
}
EXPORT_SYMBOL_GPL(tcp_done);
extern struct tcp_congestion_ops tcp_reno;
static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
if (!str)
return 0;
thash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("thash_entries=", set_thash_entries);
void __init tcp_init(void)
{
struct sk_buff *skb = NULL;
unsigned long nr_pages, limit;
int order, i, max_share;
BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
tcp_hashinfo.bind_bucket_cachep =
kmem_cache_create("tcp_bind_bucket",
sizeof(struct inet_bind_bucket), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
/* Size and allocate the main established and bind bucket
* hash tables.
*
* The methodology is similar to that of the buffer cache.
*/
tcp_hashinfo.ehash =
alloc_large_system_hash("TCP established",
sizeof(struct inet_ehash_bucket),
thash_entries,
(num_physpages >= 128 * 1024) ?
13 : 15,
0,
&tcp_hashinfo.ehash_size,
NULL,
thash_entries ? 0 : 512 * 1024);
tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
}
if (inet_ehash_locks_alloc(&tcp_hashinfo))
panic("TCP: failed to alloc ehash_locks");
tcp_hashinfo.bhash =
alloc_large_system_hash("TCP bind",
sizeof(struct inet_bind_hashbucket),
tcp_hashinfo.ehash_size,
(num_physpages >= 128 * 1024) ?
13 : 15,
0,
&tcp_hashinfo.bhash_size,
NULL,
64 * 1024);
tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
spin_lock_init(&tcp_hashinfo.bhash[i].lock);
INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
}
/* Try to be a bit smarter and adjust defaults depending
* on available memory.
*/
for (order = 0; ((1 << order) << PAGE_SHIFT) <
(tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
order++)
;
if (order >= 4) {
tcp_death_row.sysctl_max_tw_buckets = 180000;
sysctl_tcp_max_orphans = 4096 << (order - 4);
sysctl_max_syn_backlog = 1024;
} else if (order < 3) {
tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
sysctl_tcp_max_orphans >>= (3 - order);
sysctl_max_syn_backlog = 128;
}
/* Set the pressure threshold to be a fraction of global memory that
* is up to 1/2 at 256 MB, decreasing toward zero with the amount of
* memory, with a floor of 128 pages.
*/
nr_pages = totalram_pages - totalhigh_pages;
limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
limit = max(limit, 128UL);
sysctl_tcp_mem[0] = limit / 4 * 3;
sysctl_tcp_mem[1] = limit;
sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
/* Set per-socket limits to no more than 1/128 the pressure threshold */
limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
max_share = min(4UL*1024*1024, limit);
sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
sysctl_tcp_wmem[1] = 16*1024;
sysctl_tcp_wmem[2] = max(64*1024, max_share);
sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
sysctl_tcp_rmem[1] = 87380;
sysctl_tcp_rmem[2] = max(87380, max_share);
printk(KERN_INFO "TCP: Hash tables configured "
"(established %d bind %d)\n",
tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
tcp_register_congestion_control(&tcp_reno);
}
EXPORT_SYMBOL(tcp_close);
EXPORT_SYMBOL(tcp_disconnect);
EXPORT_SYMBOL(tcp_getsockopt);
EXPORT_SYMBOL(tcp_ioctl);
EXPORT_SYMBOL(tcp_poll);
EXPORT_SYMBOL(tcp_read_sock);
EXPORT_SYMBOL(tcp_recvmsg);
EXPORT_SYMBOL(tcp_sendmsg);
EXPORT_SYMBOL(tcp_splice_read);
EXPORT_SYMBOL(tcp_sendpage);
EXPORT_SYMBOL(tcp_setsockopt);
EXPORT_SYMBOL(tcp_shutdown);
EXPORT_SYMBOL(tcp_statistics);