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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/tcp.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c2386
1 files changed, 2386 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
new file mode 100644
index 000000000000..5cff56af7855
--- /dev/null
+++ b/net/ipv4/tcp.c
@@ -0,0 +1,2386 @@
+/*
+ * 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 1.216 2002/02/01 22:01:04 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 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/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/poll.h>
+#include <linux/init.h>
+#include <linux/smp_lock.h>
+#include <linux/fs.h>
+#include <linux/random.h>
+#include <linux/bootmem.h>
+
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <net/xfrm.h>
+#include <net/ip.h>
+
+
+#include <asm/uaccess.h>
+#include <asm/ioctls.h>
+
+int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
+
+DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
+
+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 };
+
+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);
+
+/*
+ * Pressure flag: try to collapse.
+ * Technical note: it is used by multiple contexts non atomically.
+ * All the sk_stream_mem_schedule() is of this nature: accounting
+ * is strict, actions are advisory and have some latency.
+ */
+int tcp_memory_pressure;
+
+EXPORT_SYMBOL(tcp_memory_pressure);
+
+void tcp_enter_memory_pressure(void)
+{
+ if (!tcp_memory_pressure) {
+ NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
+ tcp_memory_pressure = 1;
+ }
+}
+
+EXPORT_SYMBOL(tcp_enter_memory_pressure);
+
+/*
+ * LISTEN is a special case for poll..
+ */
+static __inline__ unsigned int tcp_listen_poll(struct sock *sk,
+ poll_table *wait)
+{
+ return tcp_sk(sk)->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_sock *tp = tcp_sk(sk);
+
+ poll_wait(file, sk->sk_sleep, wait);
+ if (sk->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->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->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
+ mask |= POLLHUP;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= POLLIN | POLLRDNORM;
+
+ /* 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 -=
+ ((struct sk_buff *)sk->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->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);
+}
+
+
+int tcp_listen_start(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_listen_opt *lopt;
+
+ sk->sk_max_ack_backlog = 0;
+ sk->sk_ack_backlog = 0;
+ tp->accept_queue = tp->accept_queue_tail = NULL;
+ rwlock_init(&tp->syn_wait_lock);
+ tcp_delack_init(tp);
+
+ 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;
+ get_random_bytes(&lopt->hash_rnd, 4);
+
+ 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->sk_state = TCP_LISTEN;
+ if (!sk->sk_prot->get_port(sk, inet->num)) {
+ inet->sport = htons(inet->num);
+
+ sk_dst_reset(sk);
+ sk->sk_prot->hash(sk);
+
+ return 0;
+ }
+
+ sk->sk_state = TCP_CLOSE;
+ 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_sock *tp = tcp_sk(sk);
+ 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);
+
+ 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(!sock_owned_by_user(child));
+ 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);
+
+ sk_acceptq_removed(sk);
+ tcp_openreq_fastfree(req);
+ }
+ BUG_TRAP(!sk->sk_ack_backlog);
+}
+
+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 tcp_sock *tp,
+ struct sk_buff *skb)
+{
+ skb->csum = 0;
+ TCP_SKB_CB(skb)->seq = tp->write_seq;
+ TCP_SKB_CB(skb)->end_seq = tp->write_seq;
+ TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
+ TCP_SKB_CB(skb)->sacked = 0;
+ skb_header_release(skb);
+ __skb_queue_tail(&sk->sk_write_queue, skb);
+ sk_charge_skb(sk, skb);
+ if (!sk->sk_send_head)
+ sk->sk_send_head = skb;
+ else 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;
+ TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
+ }
+}
+
+static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags,
+ int mss_now, int nonagle)
+{
+ if (sk->sk_send_head) {
+ struct sk_buff *skb = sk->sk_write_queue.prev;
+ if (!(flags & MSG_MORE) || forced_push(tp))
+ tcp_mark_push(tp, skb);
+ tcp_mark_urg(tp, flags, skb);
+ __tcp_push_pending_frames(sk, tp, mss_now,
+ (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
+ }
+}
+
+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;
+ 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));
+ copied = 0;
+
+ err = -EPIPE;
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+ goto do_error;
+
+ while (psize > 0) {
+ struct sk_buff *skb = sk->sk_write_queue.prev;
+ 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 (!sk->sk_send_head || (copy = mss_now - skb->len) <= 0) {
+new_segment:
+ if (!sk_stream_memory_free(sk))
+ goto wait_for_sndbuf;
+
+ skb = sk_stream_alloc_pskb(sk, 0, 0,
+ sk->sk_allocation);
+ if (!skb)
+ goto wait_for_memory;
+
+ skb_entail(sk, tp, skb);
+ copy = mss_now;
+ }
+
+ 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->sk_forward_alloc < copy &&
+ !sk_stream_mem_schedule(sk, copy, 0))
+ 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->sk_forward_alloc -= copy;
+ skb->ip_summed = CHECKSUM_HW;
+ tp->write_seq += copy;
+ TCP_SKB_CB(skb)->end_seq += copy;
+ skb_shinfo(skb)->tso_segs = 0;
+
+ if (!copied)
+ TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
+
+ copied += copy;
+ poffset += copy;
+ if (!(psize -= copy))
+ goto out;
+
+ if (skb->len != mss_now || (flags & MSG_OOB))
+ continue;
+
+ if (forced_push(tp)) {
+ tcp_mark_push(tp, skb);
+ __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
+ } else if (skb == sk->sk_send_head)
+ 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, tp, 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));
+ }
+
+out:
+ if (copied)
+ tcp_push(sk, tp, 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;
+
+#define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
+
+ if (!(sk->sk_route_caps & NETIF_F_SG) ||
+ !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
+ return sock_no_sendpage(sock, page, offset, size, flags);
+
+#undef TCP_ZC_CSUM_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)
+{
+ int tmp = tp->mss_cache_std;
+
+ if (sk->sk_route_caps & NETIF_F_SG) {
+ 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 sock *sk, struct msghdr *msg,
+ size_t size)
+{
+ struct iovec *iov;
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb;
+ int iovlen, flags;
+ int mss_now;
+ 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));
+
+ /* 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 = sk->sk_write_queue.prev;
+
+ if (!sk->sk_send_head ||
+ (copy = mss_now - 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_pskb(sk, select_size(sk, tp),
+ 0, sk->sk_allocation);
+ if (!skb)
+ goto wait_for_memory;
+
+ /*
+ * Check whether we can use HW checksum.
+ */
+ if (sk->sk_route_caps &
+ (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
+ NETIF_F_HW_CSUM))
+ skb->ip_summed = CHECKSUM_HW;
+
+ skb_entail(sk, tp, skb);
+ copy = mss_now;
+ }
+
+ /* 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 page is cached, align
+ * offset to L1 cache boundary
+ */
+ off = (off + L1_CACHE_BYTES - 1) &
+ ~(L1_CACHE_BYTES - 1);
+ if (off == PAGE_SIZE) {
+ put_page(page);
+ TCP_PAGE(sk) = page = NULL;
+ }
+ }
+
+ if (!page) {
+ /* Allocate new cache page. */
+ if (!(page = sk_stream_alloc_page(sk)))
+ goto wait_for_memory;
+ off = 0;
+ }
+
+ if (copy > PAGE_SIZE - off)
+ copy = PAGE_SIZE - off;
+
+ /* 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)->tso_segs = 0;
+
+ from += copy;
+ copied += copy;
+ if ((seglen -= copy) == 0 && iovlen == 0)
+ goto out;
+
+ if (skb->len != mss_now || (flags & MSG_OOB))
+ continue;
+
+ if (forced_push(tp)) {
+ tcp_mark_push(tp, skb);
+ __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
+ } else if (skb == sk->sk_send_head)
+ 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, tp, 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));
+ }
+ }
+
+out:
+ if (copied)
+ tcp_push(sk, tp, flags, mss_now, tp->nonagle);
+ TCP_CHECK_TIMER(sk);
+ release_sock(sk);
+ return copied;
+
+do_fault:
+ if (!skb->len) {
+ if (sk->sk_send_head == skb)
+ sk->sk_send_head = NULL;
+ __skb_unlink(skb, skb->list);
+ sk_stream_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.
+ */
+static void 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 (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->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_ADD_STATS_USER(LINUX_MIB_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->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 (skb->h.th->syn)
+ offset--;
+ if (offset < skb->len || skb->h.th->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) {
+ size_t used, 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 <= len) {
+ seq += used;
+ copied += used;
+ offset += used;
+ }
+ if (offset != skb->len)
+ break;
+ }
+ if (skb->h.th->fin) {
+ sk_eat_skb(sk, skb);
+ ++seq;
+ break;
+ }
+ sk_eat_skb(sk, skb);
+ 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)
+ 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;
+
+ 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);
+
+ do {
+ struct sk_buff *skb;
+ 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 (skb->h.th->syn)
+ offset--;
+ if (offset < skb->len)
+ goto found_ok_skb;
+ if (skb->h.th->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;
+ }
+ }
+
+ cleanup_rbuf(sk, copied);
+
+ if (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_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
+ sk_wait_data(sk, &timeo);
+
+ 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_len(&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, current->pid);
+ 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)) {
+ 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, tp);
+ }
+ if (used + offset < skb->len)
+ continue;
+
+ if (skb->h.th->fin)
+ goto found_fin_ok;
+ if (!(flags & MSG_PEEK))
+ sk_eat_skb(sk, skb);
+ continue;
+
+ found_fin_ok:
+ /* Process the FIN. */
+ ++*seq;
+ if (!(flags & MSG_PEEK))
+ sk_eat_skb(sk, skb);
+ 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_ADD_STATS_USER(LINUX_MIB_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->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_sock_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);
+ }
+}
+
+/*
+ * 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->sk_state == TCP_CLOSE);
+ BUG_TRAP(sock_flag(sk, SOCK_DEAD));
+
+ /* It cannot be in hash table! */
+ BUG_TRAP(sk_unhashed(sk));
+
+ /* If it has not 0 inet_sk(sk)->num, it must be bound */
+ BUG_TRAP(!inet_sk(sk)->num || tcp_sk(sk)->bind_hash);
+
+ sk->sk_prot->destroy(sk);
+
+ sk_stream_kill_queues(sk);
+
+ xfrm_sk_free_policy(sk);
+
+#ifdef INET_REFCNT_DEBUG
+ if (atomic_read(&sk->sk_refcnt) != 1) {
+ printk(KERN_DEBUG "Destruction TCP %p delayed, c=%d\n",
+ sk, atomic_read(&sk->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->sk_shutdown = SHUTDOWN_MASK;
+
+ if (sk->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->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);
+ }
+
+ sk_stream_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) {
+ /* 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:
+ /* 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));
+
+ 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->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(LINUX_MIB_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->sk_state != TCP_CLOSE) {
+ sk_stream_mem_reclaim(sk);
+ if (atomic_read(&tcp_orphan_count) > sysctl_tcp_max_orphans ||
+ (sk->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(LINUX_MIB_TCPABORTONMEMORY);
+ }
+ }
+ atomic_inc(&tcp_orphan_count);
+
+ if (sk->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 */
+
+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 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) {
+ 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->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);
+ sk_stream_writequeue_purge(sk);
+ __skb_queue_purge(&tp->out_of_order_queue);
+
+ 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;
+ tp->backoff = 0;
+ tp->snd_cwnd = 2;
+ tp->probes_out = 0;
+ tp->packets_out = 0;
+ tp->snd_ssthresh = 0x7fffffff;
+ tp->snd_cwnd_cnt = 0;
+ tcp_set_ca_state(tp, TCP_CA_Open);
+ tcp_clear_retrans(tp);
+ tcp_delack_init(tp);
+ sk->sk_send_head = NULL;
+ tp->rx_opt.saw_tstamp = 0;
+ tcp_sack_reset(&tp->rx_opt);
+ __sk_dst_reset(sk);
+
+ BUG_TRAP(!inet->num || tp->bind_hash);
+
+ sk->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)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ DEFINE_WAIT(wait);
+ int err;
+
+ /*
+ * True wake-one mechanism for incoming connections: only
+ * one process gets woken up, not the 'whole herd'.
+ * Since we do not 'race & poll' for established sockets
+ * anymore, the common case will execute the loop only once.
+ *
+ * Subtle issue: "add_wait_queue_exclusive()" will be added
+ * after any current non-exclusive waiters, and we know that
+ * it will always _stay_ after any new non-exclusive waiters
+ * because all non-exclusive waiters are added at the
+ * beginning of the wait-queue. As such, it's ok to "drop"
+ * our exclusiveness temporarily when we get woken up without
+ * having to remove and re-insert us on the wait queue.
+ */
+ for (;;) {
+ prepare_to_wait_exclusive(sk->sk_sleep, &wait,
+ TASK_INTERRUPTIBLE);
+ release_sock(sk);
+ if (!tp->accept_queue)
+ timeo = schedule_timeout(timeo);
+ lock_sock(sk);
+ err = 0;
+ if (tp->accept_queue)
+ break;
+ err = -EINVAL;
+ if (sk->sk_state != TCP_LISTEN)
+ break;
+ err = sock_intr_errno(timeo);
+ if (signal_pending(current))
+ break;
+ err = -EAGAIN;
+ if (!timeo)
+ break;
+ }
+ finish_wait(sk->sk_sleep, &wait);
+ return err;
+}
+
+/*
+ * This will accept the next outstanding connection.
+ */
+
+struct sock *tcp_accept(struct sock *sk, int flags, int *err)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ 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->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;
+ sk_acceptq_removed(sk);
+ tcp_openreq_fastfree(req);
+ BUG_TRAP(newsk->sk_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 __user *optval,
+ int optlen)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ 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 __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, tp);
+ } 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, tp);
+ }
+ 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;
+ 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 (tp->defer_accept < 32 &&
+ val > ((TCP_TIMEOUT_INIT / HZ) <<
+ tp->defer_accept))
+ tp->defer_accept++;
+ tp->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) {
+ tp->ack.pingpong = 1;
+ } else {
+ tp->ack.pingpong = 0;
+ if ((1 << sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
+ tcp_ack_scheduled(tp)) {
+ tp->ack.pending |= TCP_ACK_PUSHED;
+ cleanup_rbuf(sk, 1);
+ if (!(val & 1))
+ tp->ack.pingpong = 1;
+ }
+ }
+ break;
+
+ default:
+ err = -ENOPROTOOPT;
+ break;
+ };
+ release_sock(sk);
+ return err;
+}
+
+/* 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);
+ u32 now = tcp_time_stamp;
+
+ memset(info, 0, sizeof(*info));
+
+ info->tcpi_state = sk->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;
+
+ if (tp->rx_opt.tstamp_ok)
+ info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
+ if (tp->rx_opt.sack_ok)
+ 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(tp->rto);
+ info->tcpi_ato = jiffies_to_usecs(tp->ack.ato);
+ info->tcpi_snd_mss = tp->mss_cache_std;
+ 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 = jiffies_to_msecs(now - tp->lsndtime);
+ info->tcpi_last_data_recv = jiffies_to_msecs(now - tp->ack.lrcvtime);
+ info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
+
+ info->tcpi_pmtu = tp->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);
+
+int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
+ int __user *optlen)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ 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_t(unsigned int, len, sizeof(int));
+
+ if (len < 0)
+ return -EINVAL;
+
+ switch (optname) {
+ case TCP_MAXSEG:
+ val = tp->mss_cache_std;
+ 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 = 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 : ((TCP_TIMEOUT_INIT / HZ) <<
+ (tp->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 = !tp->ack.pingpong;
+ break;
+ 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);
+extern void tcpdiag_init(void);
+
+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;
+ 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.
+ */
+ tcp_ehash = (struct tcp_ehash_bucket *)
+ alloc_large_system_hash("TCP established",
+ sizeof(struct tcp_ehash_bucket),
+ thash_entries,
+ (num_physpages >= 128 * 1024) ?
+ (25 - PAGE_SHIFT) :
+ (27 - PAGE_SHIFT),
+ HASH_HIGHMEM,
+ &tcp_ehash_size,
+ NULL,
+ 0);
+ tcp_ehash_size = (1 << tcp_ehash_size) >> 1;
+ for (i = 0; i < (tcp_ehash_size << 1); i++) {
+ rwlock_init(&tcp_ehash[i].lock);
+ INIT_HLIST_HEAD(&tcp_ehash[i].chain);
+ }
+
+ tcp_bhash = (struct tcp_bind_hashbucket *)
+ alloc_large_system_hash("TCP bind",
+ sizeof(struct tcp_bind_hashbucket),
+ tcp_ehash_size,
+ (num_physpages >= 128 * 1024) ?
+ (25 - PAGE_SHIFT) :
+ (27 - PAGE_SHIFT),
+ HASH_HIGHMEM,
+ &tcp_bhash_size,
+ NULL,
+ 64 * 1024);
+ tcp_bhash_size = 1 << tcp_bhash_size;
+ for (i = 0; i < tcp_bhash_size; i++) {
+ spin_lock_init(&tcp_bhash[i].lock);
+ INIT_HLIST_HEAD(&tcp_bhash[i].chain);
+ }
+
+ /* Try to be a bit smarter and adjust defaults depending
+ * on available memory.
+ */
+ for (order = 0; ((1 << order) << PAGE_SHIFT) <
+ (tcp_bhash_size * sizeof(struct tcp_bind_hashbucket));
+ order++)
+ ;
+ 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] = 768 << order;
+ sysctl_tcp_mem[1] = 1024 << order;
+ sysctl_tcp_mem[2] = 1536 << order;
+
+ 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(KERN_INFO "TCP: Hash tables configured "
+ "(established %d bind %d)\n",
+ tcp_ehash_size << 1, tcp_bhash_size);
+}
+
+EXPORT_SYMBOL(tcp_accept);
+EXPORT_SYMBOL(tcp_close);
+EXPORT_SYMBOL(tcp_destroy_sock);
+EXPORT_SYMBOL(tcp_disconnect);
+EXPORT_SYMBOL(tcp_getsockopt);
+EXPORT_SYMBOL(tcp_ioctl);
+EXPORT_SYMBOL(tcp_openreq_cachep);
+EXPORT_SYMBOL(tcp_poll);
+EXPORT_SYMBOL(tcp_read_sock);
+EXPORT_SYMBOL(tcp_recvmsg);
+EXPORT_SYMBOL(tcp_sendmsg);
+EXPORT_SYMBOL(tcp_sendpage);
+EXPORT_SYMBOL(tcp_setsockopt);
+EXPORT_SYMBOL(tcp_shutdown);
+EXPORT_SYMBOL(tcp_statistics);
+EXPORT_SYMBOL(tcp_timewait_cachep);