--- /dev/null
+/*
+ * 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
+ */
+
+#define pr_fmt(fmt) "TCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/poll.h>
+#include <linux/inet_diag.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 <linux/time.h>
+#include <linux/slab.h>
+
+#include <net/icmp.h>
+#include <net/inet_common.h>
+#include <net/tcp.h>
+#include <net/xfrm.h>
+#include <net/ip.h>
+#include <net/sock.h>
+
+#include <asm/uaccess.h>
+#include <asm/ioctls.h>
+#include <net/busy_poll.h>
+
+int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
+
+int sysctl_tcp_min_tso_segs __read_mostly = 2;
+
+int sysctl_tcp_autocorking __read_mostly = 1;
+
+struct percpu_counter tcp_orphan_count;
+EXPORT_SYMBOL_GPL(tcp_orphan_count);
+
+long 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_long_t tcp_memory_allocated; /* Current allocated memory. */
+EXPORT_SYMBOL(tcp_memory_allocated);
+
+/*
+ * Current number of TCP sockets.
+ */
+struct percpu_counter tcp_sockets_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);
+
+/* Convert seconds to retransmits based on initial and max timeout */
+static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
+{
+ u8 res = 0;
+
+ if (seconds > 0) {
+ int period = timeout;
+
+ res = 1;
+ while (seconds > period && res < 255) {
+ res++;
+ timeout <<= 1;
+ if (timeout > rto_max)
+ timeout = rto_max;
+ period += timeout;
+ }
+ }
+ return res;
+}
+
+/* Convert retransmits to seconds based on initial and max timeout */
+static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
+{
+ int period = 0;
+
+ if (retrans > 0) {
+ period = timeout;
+ while (--retrans) {
+ timeout <<= 1;
+ if (timeout > rto_max)
+ timeout = rto_max;
+ period += timeout;
+ }
+ }
+ return period;
+}
+
+/* Address-family independent initialization for a tcp_sock.
+ *
+ * NOTE: A lot of things set to zero explicitly by call to
+ * sk_alloc() so need not be done here.
+ */
+void tcp_init_sock(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ __skb_queue_head_init(&tp->out_of_order_queue);
+ tcp_init_xmit_timers(sk);
+ tcp_prequeue_init(tp);
+ INIT_LIST_HEAD(&tp->tsq_node);
+
+ icsk->icsk_rto = TCP_TIMEOUT_INIT;
+ tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
+
+ /* So many TCP implementations out there (incorrectly) count the
+ * initial SYN frame in their delayed-ACK and congestion control
+ * algorithms that we must have the following bandaid to talk
+ * efficiently to them. -DaveM
+ */
+ tp->snd_cwnd = TCP_INIT_CWND;
+
+ /* See draft-stevens-tcpca-spec-01 for discussion of the
+ * initialization of these values.
+ */
+ tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
+ tp->snd_cwnd_clamp = ~0;
+ tp->mss_cache = TCP_MSS_DEFAULT;
+ u64_stats_init(&tp->syncp);
+
+ tp->reordering = sysctl_tcp_reordering;
+ tcp_enable_early_retrans(tp);
+ tcp_assign_congestion_control(sk);
+
+ tp->tsoffset = 0;
+
+ sk->sk_state = TCP_CLOSE;
+
+ sk->sk_write_space = sk_stream_write_space;
+ sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
+
+ icsk->icsk_sync_mss = tcp_sync_mss;
+
+ sk->sk_sndbuf = sysctl_tcp_wmem[1];
+ sk->sk_rcvbuf = sysctl_tcp_rmem[1];
+
+ local_bh_disable();
+ sock_update_memcg(sk);
+ sk_sockets_allocated_inc(sk);
+ local_bh_enable();
+}
+EXPORT_SYMBOL(tcp_init_sock);
+
+static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
+{
+ if (sk->sk_tsflags) {
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+
+ sock_tx_timestamp(sk, &shinfo->tx_flags);
+ if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
+ shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
+ }
+}
+
+/*
+ * 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;
+ const struct tcp_sock *tp = tcp_sk(sk);
+
+ sock_rps_record_flow(sk);
+
+ sock_poll_wait(file, sk_sleep(sk), 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;
+
+ /*
+ * 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 or passive Fast Open socket? */
+ if (sk->sk_state != TCP_SYN_SENT &&
+ (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk)) {
+ int target = sock_rcvlowat(sk, 0, INT_MAX);
+
+ if (tp->urg_seq == tp->copied_seq &&
+ !sock_flag(sk, SOCK_URGINLINE) &&
+ tp->urg_data)
+ target++;
+
+ /* 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 >= target)
+ mask |= POLLIN | POLLRDNORM;
+
+ if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
+ if (sk_stream_is_writeable(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. Memory barrier
+ * pairs with the input side.
+ */
+ smp_mb__after_atomic();
+ if (sk_stream_is_writeable(sk))
+ mask |= POLLOUT | POLLWRNORM;
+ }
+ } else
+ mask |= POLLOUT | POLLWRNORM;
+
+ if (tp->urg_data & TCP_URG_VALID)
+ mask |= POLLPRI;
+ }
+ /* This barrier is coupled with smp_wmb() in tcp_reset() */
+ smp_rmb();
+ if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
+ mask |= POLLERR;
+
+ return mask;
+}
+EXPORT_SYMBOL(tcp_poll);
+
+int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ int answ;
+ bool slow;
+
+ switch (cmd) {
+ case SIOCINQ:
+ if (sk->sk_state == TCP_LISTEN)
+ return -EINVAL;
+
+ slow = lock_sock_fast(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 was received */
+ if (answ && sock_flag(sk, SOCK_DONE))
+ answ--;
+ } else
+ answ = tp->urg_seq - tp->copied_seq;
+ unlock_sock_fast(sk, slow);
+ 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;
+ case SIOCOUTQNSD:
+ 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_nxt;
+ break;
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ return put_user(answ, (int __user *)arg);
+}
+EXPORT_SYMBOL(tcp_ioctl);
+
+static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
+{
+ TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
+ tp->pushed_seq = tp->write_seq;
+}
+
+static inline bool forced_push(const struct tcp_sock *tp)
+{
+ return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
+}
+
+static 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->tcp_flags = TCPHDR_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)
+{
+ if (flags & MSG_OOB)
+ tp->snd_up = tp->write_seq;
+}
+
+/* If a not yet filled skb is pushed, do not send it if
+ * we have data packets in Qdisc or NIC queues :
+ * Because TX completion will happen shortly, it gives a chance
+ * to coalesce future sendmsg() payload into this skb, without
+ * need for a timer, and with no latency trade off.
+ * As packets containing data payload have a bigger truesize
+ * than pure acks (dataless) packets, the last checks prevent
+ * autocorking if we only have an ACK in Qdisc/NIC queues,
+ * or if TX completion was delayed after we processed ACK packet.
+ */
+static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
+ int size_goal)
+{
+ return skb->len < size_goal &&
+ sysctl_tcp_autocorking &&
+ skb != tcp_write_queue_head(sk) &&
+ atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
+}
+
+static void tcp_push(struct sock *sk, int flags, int mss_now,
+ int nonagle, int size_goal)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb;
+
+ if (!tcp_send_head(sk))
+ return;
+
+ skb = tcp_write_queue_tail(sk);
+ if (!(flags & MSG_MORE) || forced_push(tp))
+ tcp_mark_push(tp, skb);
+
+ tcp_mark_urg(tp, flags);
+
+ if (tcp_should_autocork(sk, skb, size_goal)) {
+
+ /* avoid atomic op if TSQ_THROTTLED bit is already set */
+ if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
+ set_bit(TSQ_THROTTLED, &tp->tsq_flags);
+ }
+ /* It is possible TX completion already happened
+ * before we set TSQ_THROTTLED.
+ */
+ if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
+ return;
+ }
+
+ if (flags & MSG_MORE)
+ nonagle = TCP_NAGLE_CORK;
+
+ __tcp_push_pending_frames(sk, mss_now, 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;
+ int ret;
+
+ ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
+ tss->flags);
+ if (ret > 0)
+ rd_desc->count -= ret;
+ return ret;
+}
+
+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,
+ .count = tss->len,
+ };
+
+ 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;
+
+ sock_rps_record_flow(sk);
+ /*
+ * We can't seek on a socket input
+ */
+ if (unlikely(*ppos))
+ return -ESPIPE;
+
+ ret = spliced = 0;
+
+ lock_sock(sk);
+
+ timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
+ while (tss.len) {
+ ret = __tcp_splice_read(sk, &tss);
+ if (ret < 0)
+ break;
+ else if (!ret) {
+ if (spliced)
+ 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;
+
+ if (!timeo)
+ break;
+ release_sock(sk);
+ lock_sock(sk);
+
+ if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
+ (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ signal_pending(current))
+ break;
+ }
+
+ release_sock(sk);
+
+ if (spliced)
+ return spliced;
+
+ return ret;
+}
+EXPORT_SYMBOL(tcp_splice_read);
+
+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)) {
+ skb_reserve(skb, sk->sk_prot->max_header);
+ /*
+ * Make sure that we have exactly size bytes
+ * available to the caller, no more, no less.
+ */
+ skb->reserved_tailroom = skb->end - skb->tail - size;
+ return skb;
+ }
+ __kfree_skb(skb);
+ } else {
+ sk->sk_prot->enter_memory_pressure(sk);
+ sk_stream_moderate_sndbuf(sk);
+ }
+ return NULL;
+}
+
+static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
+ int large_allowed)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ u32 new_size_goal, size_goal;
+
+ if (!large_allowed || !sk_can_gso(sk))
+ return mss_now;
+
+ /* Note : tcp_tso_autosize() will eventually split this later */
+ new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
+ new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
+
+ /* We try hard to avoid divides here */
+ size_goal = tp->gso_segs * mss_now;
+ if (unlikely(new_size_goal < size_goal ||
+ new_size_goal >= size_goal + mss_now)) {
+ tp->gso_segs = min_t(u16, new_size_goal / mss_now,
+ sk->sk_gso_max_segs);
+ size_goal = tp->gso_segs * mss_now;
+ }
+
+ return max(size_goal, mss_now);
+}
+
+static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
+{
+ int mss_now;
+
+ mss_now = tcp_current_mss(sk);
+ *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
+
+ return mss_now;
+}
+
+static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
+ size_t size, 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. One exception is TCP Fast Open
+ * (passive side) where data is allowed to be sent before a connection
+ * is fully established.
+ */
+ if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
+ !tcp_passive_fastopen(sk)) {
+ if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
+ goto out_err;
+ }
+
+ clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
+ copied = 0;
+
+ err = -EPIPE;
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+ goto out_err;
+
+ while (size > 0) {
+ struct sk_buff *skb = tcp_write_queue_tail(sk);
+ int copy, i;
+ bool can_coalesce;
+
+ 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_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ get_page(page);
+ skb_fill_page_desc(skb, i, page, offset, copy);
+ }
+ skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
+
+ 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;
+ tcp_skb_pcount_set(skb, 0);
+
+ if (!copied)
+ TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
+
+ copied += copy;
+ offset += copy;
+ if (!(size -= copy)) {
+ tcp_tx_timestamp(sk, skb);
+ 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:
+ tcp_push(sk, flags & ~MSG_MORE, mss_now,
+ TCP_NAGLE_PUSH, size_goal);
+
+ if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
+ goto do_error;
+
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
+ }
+
+out:
+ if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
+ tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
+ return copied;
+
+do_error:
+ if (copied)
+ goto out;
+out_err:
+ return sk_stream_error(sk, flags, err);
+}
+
+int tcp_sendpage(struct sock *sk, struct page *page, int offset,
+ size_t size, int flags)
+{
+ ssize_t res;
+
+ if (!(sk->sk_route_caps & NETIF_F_SG) ||
+ !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
+ return sock_no_sendpage(sk->sk_socket, page, offset, size,
+ flags);
+
+ lock_sock(sk);
+ res = do_tcp_sendpages(sk, page, offset, size, flags);
+ release_sock(sk);
+ return res;
+}
+EXPORT_SYMBOL(tcp_sendpage);
+
+static inline int select_size(const struct sock *sk, bool sg)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ int tmp = tp->mss_cache;
+
+ if (sg) {
+ if (sk_can_gso(sk)) {
+ /* Small frames wont use a full page:
+ * Payload will immediately follow tcp header.
+ */
+ tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
+ } else {
+ int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
+
+ if (tmp >= pgbreak &&
+ tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
+ tmp = pgbreak;
+ }
+ }
+
+ return tmp;
+}
+
+void tcp_free_fastopen_req(struct tcp_sock *tp)
+{
+ if (tp->fastopen_req) {
+ kfree(tp->fastopen_req);
+ tp->fastopen_req = NULL;
+ }
+}
+
+static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
+ int *copied, size_t size)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ int err, flags;
+
+ if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
+ return -EOPNOTSUPP;
+ if (tp->fastopen_req)
+ return -EALREADY; /* Another Fast Open is in progress */
+
+ tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
+ sk->sk_allocation);
+ if (unlikely(!tp->fastopen_req))
+ return -ENOBUFS;
+ tp->fastopen_req->data = msg;
+ tp->fastopen_req->size = size;
+
+ flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
+ err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
+ msg->msg_namelen, flags);
+ *copied = tp->fastopen_req->copied;
+ tcp_free_fastopen_req(tp);
+ return err;
+}
+
+int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb;
+ int flags, err, copied = 0;
+ int mss_now = 0, size_goal, copied_syn = 0;
+ bool sg;
+ long timeo;
+
+ lock_sock(sk);
+
+ flags = msg->msg_flags;
+ if (flags & MSG_FASTOPEN) {
+ err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
+ if (err == -EINPROGRESS && copied_syn > 0)
+ goto out;
+ else if (err)
+ goto out_err;
+ }
+
+ timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+
+ /* Wait for a connection to finish. One exception is TCP Fast Open
+ * (passive side) where data is allowed to be sent before a connection
+ * is fully established.
+ */
+ if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
+ !tcp_passive_fastopen(sk)) {
+ if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
+ goto do_error;
+ }
+
+ if (unlikely(tp->repair)) {
+ if (tp->repair_queue == TCP_RECV_QUEUE) {
+ copied = tcp_send_rcvq(sk, msg, size);
+ goto out_nopush;
+ }
+
+ err = -EINVAL;
+ if (tp->repair_queue == TCP_NO_QUEUE)
+ goto out_err;
+
+ /* 'common' sending to sendq */
+ }
+
+ /* This should be in poll */
+ clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
+
+ /* Ok commence sending. */
+ copied = 0;
+
+ err = -EPIPE;
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+ goto out_err;
+
+ sg = !!(sk->sk_route_caps & NETIF_F_SG);
+
+ while (msg_data_left(msg)) {
+ int copy = 0;
+ int max = size_goal;
+
+ skb = tcp_write_queue_tail(sk);
+ if (tcp_send_head(sk)) {
+ if (skb->ip_summed == CHECKSUM_NONE)
+ max = mss_now;
+ copy = max - skb->len;
+ }
+
+ if (copy <= 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, sg),
+ 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;
+ max = size_goal;
+
+ /* All packets are restored as if they have
+ * already been sent. skb_mstamp isn't set to
+ * avoid wrong rtt estimation.
+ */
+ if (tp->repair)
+ TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
+ }
+
+ /* Try to append data to the end of skb. */
+ if (copy > msg_data_left(msg))
+ copy = msg_data_left(msg);
+
+ /* Where to copy to? */
+ if (skb_availroom(skb) > 0) {
+ /* We have some space in skb head. Superb! */
+ copy = min_t(int, copy, skb_availroom(skb));
+ err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
+ if (err)
+ goto do_fault;
+ } else {
+ bool merge = true;
+ int i = skb_shinfo(skb)->nr_frags;
+ struct page_frag *pfrag = sk_page_frag(sk);
+
+ if (!sk_page_frag_refill(sk, pfrag))
+ goto wait_for_memory;
+
+ if (!skb_can_coalesce(skb, i, pfrag->page,
+ pfrag->offset)) {
+ if (i == MAX_SKB_FRAGS || !sg) {
+ tcp_mark_push(tp, skb);
+ goto new_segment;
+ }
+ merge = false;
+ }
+
+ copy = min_t(int, copy, pfrag->size - pfrag->offset);
+
+ if (!sk_wmem_schedule(sk, copy))
+ goto wait_for_memory;
+
+ err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
+ pfrag->page,
+ pfrag->offset,
+ copy);
+ if (err)
+ goto do_error;
+
+ /* Update the skb. */
+ if (merge) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ skb_fill_page_desc(skb, i, pfrag->page,
+ pfrag->offset, copy);
+ get_page(pfrag->page);
+ }
+ pfrag->offset += copy;
+ }
+
+ if (!copied)
+ TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
+
+ tp->write_seq += copy;
+ TCP_SKB_CB(skb)->end_seq += copy;
+ tcp_skb_pcount_set(skb, 0);
+
+ copied += copy;
+ if (!msg_data_left(msg)) {
+ tcp_tx_timestamp(sk, skb);
+ goto out;
+ }
+
+ if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
+ 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, size_goal);
+
+ if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
+ goto do_error;
+
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
+ }
+
+out:
+ if (copied)
+ tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
+out_nopush:
+ release_sock(sk);
+ return copied + copied_syn;
+
+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 + copied_syn)
+ goto out;
+out_err:
+ err = sk_stream_error(sk, flags, err);
+ release_sock(sk);
+ return err;
+}
+EXPORT_SYMBOL(tcp_sendmsg);
+
+/*
+ * 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, struct msghdr *msg, int len, int flags)
+{
+ 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_to_msg(msg, &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;
+}
+
+static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
+{
+ struct sk_buff *skb;
+ int copied = 0, err = 0;
+
+ /* XXX -- need to support SO_PEEK_OFF */
+
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
+ if (err)
+ break;
+
+ copied += skb->len;
+ }
+
+ return err ?: copied;
+}
+
+/* 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 tcp_cleanup_rbuf(struct sock *sk, int copied)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ bool time_to_ack = false;
+
+ struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
+
+ WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
+ "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
+ tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
+
+ 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 = true;
+ }
+
+ /* 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 = true;
+ }
+ }
+ 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(sock_net(sk), 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_backlog_rcv(sk, skb);
+ local_bh_enable();
+
+ /* Clear memory counter. */
+ tp->ucopy.memory = 0;
+}
+
+static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
+{
+ struct sk_buff *skb;
+ u32 offset;
+
+ while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
+ offset = seq - TCP_SKB_CB(skb)->seq;
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
+ offset--;
+ if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
+ *off = offset;
+ return skb;
+ }
+ /* This looks weird, but this can happen if TCP collapsing
+ * splitted a fat GRO packet, while we released socket lock
+ * in skb_splice_bits()
+ */
+ sk_eat_skb(sk, 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)
+ break;
+ /* TCP coalescing might have appended data to the skb.
+ * Try to splice more frags
+ */
+ if (offset + 1 != skb->len)
+ continue;
+ }
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
+ sk_eat_skb(sk, skb);
+ ++seq;
+ break;
+ }
+ sk_eat_skb(sk, skb);
+ if (!desc->count)
+ break;
+ tp->copied_seq = seq;
+ }
+ tp->copied_seq = seq;
+
+ tcp_rcv_space_adjust(sk);
+
+ /* Clean up data we have read: This will do ACK frames. */
+ if (copied > 0) {
+ tcp_recv_skb(sk, seq, &offset);
+ tcp_cleanup_rbuf(sk, copied);
+ }
+ return copied;
+}
+EXPORT_SYMBOL(tcp_read_sock);
+
+/*
+ * This routine copies from a sock struct into the user buffer.
+ *
+ * Technical note: in 2.3 we work on _locked_ socket, so that
+ * tricks with *seq access order and skb->users are not required.
+ * Probably, code can be easily improved even more.
+ */
+
+int tcp_recvmsg(struct sock *sk, struct msghdr *msg, 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;
+ struct sk_buff *skb;
+ u32 urg_hole = 0;
+
+ if (unlikely(flags & MSG_ERRQUEUE))
+ return inet_recv_error(sk, msg, len, addr_len);
+
+ if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
+ (sk->sk_state == TCP_ESTABLISHED))
+ sk_busy_loop(sk, nonblock);
+
+ lock_sock(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;
+
+ if (unlikely(tp->repair)) {
+ err = -EPERM;
+ if (!(flags & MSG_PEEK))
+ goto out;
+
+ if (tp->repair_queue == TCP_SEND_QUEUE)
+ goto recv_sndq;
+
+ err = -EINVAL;
+ if (tp->repair_queue == TCP_NO_QUEUE)
+ goto out;
+
+ /* 'common' recv queue MSG_PEEK-ing */
+ }
+
+ 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 {
+ 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_queue_walk(&sk->sk_receive_queue, skb) {
+ /* Now that we have two receive queues this
+ * shouldn't happen.
+ */
+ if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
+ "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
+ *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
+ flags))
+ break;
+
+ offset = *seq - TCP_SKB_CB(skb)->seq;
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
+ offset--;
+ if (offset < skb->len)
+ goto found_ok_skb;
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+ goto found_fin_ok;
+ WARN(!(flags & MSG_PEEK),
+ "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
+ *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
+ }
+
+ /* 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))
+ 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.msg = msg;
+ }
+
+ tp->ucopy.len = len;
+
+ WARN_ON(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);
+
+ if (user_recv) {
+ int chunk;
+
+ /* __ Restore normal policy in scheduler __ */
+
+ if ((chunk = len - tp->ucopy.len) != 0) {
+ NET_ADD_STATS_USER(sock_net(sk), 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(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
+ len -= chunk;
+ copied += chunk;
+ }
+ }
+ }
+ if ((flags & MSG_PEEK) &&
+ (peek_seq - copied - urg_hole != tp->copied_seq)) {
+ net_dbg_ratelimited("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;
+ urg_hole++;
+ offset++;
+ used--;
+ if (!used)
+ goto skip_copy;
+ }
+ } else
+ used = urg_offset;
+ }
+ }
+
+ if (!(flags & MSG_TRUNC)) {
+ err = skb_copy_datagram_msg(skb, offset, msg, 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_SKB_CB(skb)->tcp_flags & TCPHDR_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_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(sock_net(sk), 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. */
+ tcp_cleanup_rbuf(sk, copied);
+
+ release_sock(sk);
+ return copied;
+
+out:
+ release_sock(sk);
+ return err;
+
+recv_urg:
+ err = tcp_recv_urg(sk, msg, len, flags);
+ goto out;
+
+recv_sndq:
+ err = tcp_peek_sndq(sk, msg, len);
+ goto out;
+}
+EXPORT_SYMBOL(tcp_recvmsg);
+
+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: */
+ [0 /* (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,
+ [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
+};
+
+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);
+ }
+}
+EXPORT_SYMBOL(tcp_shutdown);
+
+bool tcp_check_oom(struct sock *sk, int shift)
+{
+ bool too_many_orphans, out_of_socket_memory;
+
+ too_many_orphans = tcp_too_many_orphans(sk, shift);
+ out_of_socket_memory = tcp_out_of_memory(sk);
+
+ if (too_many_orphans)
+ net_info_ratelimited("too many orphaned sockets\n");
+ if (out_of_socket_memory)
+ net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
+ return too_many_orphans || out_of_socket_memory;
+}
+
+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;
+
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+ len--;
+ data_was_unread += len;
+ __kfree_skb(skb);
+ }
+
+ sk_mem_reclaim(sk);
+
+ /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
+ if (sk->sk_state == TCP_CLOSE)
+ goto adjudge_to_death;
+
+ /* 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 (unlikely(tcp_sk(sk)->repair)) {
+ sk->sk_prot->disconnect(sk, 0);
+ } else if (data_was_unread) {
+ /* Unread data was tossed, zap the connection. */
+ NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
+ tcp_set_state(sk, TCP_CLOSE);
+ tcp_send_active_reset(sk, sk->sk_allocation);
+ } 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(sock_net(sk), 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
+ * XXX (TFO) - To start off we don't support SYN+ACK+FIN
+ * in a single packet! (May consider it later but will
+ * probably need API support or TCP_CORK SYN-ACK until
+ * data is written and socket is closed.)
+ */
+ tcp_send_fin(sk);
+ }
+
+ sk_stream_wait_close(sk, timeout);
+
+adjudge_to_death:
+ state = sk->sk_state;
+ sock_hold(sk);
+ sock_orphan(sk);
+
+ /* 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);
+ WARN_ON(sock_owned_by_user(sk));
+
+ percpu_counter_inc(sk->sk_prot->orphan_count);
+
+ /* 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 1 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_check_oom(sk, 0)) {
+ 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) {
+ struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
+ /* We could get here with a non-NULL req if the socket is
+ * aborted (e.g., closed with unread data) before 3WHS
+ * finishes.
+ */
+ if (req)
+ reqsk_fastopen_remove(sk, req, false);
+ inet_csk_destroy_sock(sk);
+ }
+ /* Otherwise, socket is reprieved until protocol close. */
+
+out:
+ bh_unlock_sock(sk);
+ local_bh_enable();
+ sock_put(sk);
+}
+EXPORT_SYMBOL(tcp_close);
+
+/* These states need RST on ABORT according to RFC793 */
+
+static inline bool 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 (unlikely(tp->repair)) {
+ sk->sk_err = ECONNABORTED;
+ } 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);
+
+ inet->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_us = 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 = TCP_INFINITE_SSTHRESH;
+ tp->snd_cwnd_cnt = 0;
+ tp->window_clamp = 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);
+
+ WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
+
+ sk->sk_error_report(sk);
+ return err;
+}
+EXPORT_SYMBOL(tcp_disconnect);
+
+void tcp_sock_destruct(struct sock *sk)
+{
+ inet_sock_destruct(sk);
+
+ kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
+}
+
+static inline bool tcp_can_repair_sock(const struct sock *sk)
+{
+ return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
+ ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
+}
+
+static int tcp_repair_options_est(struct tcp_sock *tp,
+ struct tcp_repair_opt __user *optbuf, unsigned int len)
+{
+ struct tcp_repair_opt opt;
+
+ while (len >= sizeof(opt)) {
+ if (copy_from_user(&opt, optbuf, sizeof(opt)))
+ return -EFAULT;
+
+ optbuf++;
+ len -= sizeof(opt);
+
+ switch (opt.opt_code) {
+ case TCPOPT_MSS:
+ tp->rx_opt.mss_clamp = opt.opt_val;
+ break;
+ case TCPOPT_WINDOW:
+ {
+ u16 snd_wscale = opt.opt_val & 0xFFFF;
+ u16 rcv_wscale = opt.opt_val >> 16;
+
+ if (snd_wscale > 14 || rcv_wscale > 14)
+ return -EFBIG;
+
+ tp->rx_opt.snd_wscale = snd_wscale;
+ tp->rx_opt.rcv_wscale = rcv_wscale;
+ tp->rx_opt.wscale_ok = 1;
+ }
+ break;
+ case TCPOPT_SACK_PERM:
+ if (opt.opt_val != 0)
+ return -EINVAL;
+
+ tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
+ if (sysctl_tcp_fack)
+ tcp_enable_fack(tp);
+ break;
+ case TCPOPT_TIMESTAMP:
+ if (opt.opt_val != 0)
+ return -EINVAL;
+
+ tp->rx_opt.tstamp_ok = 1;
+ break;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Socket option code for TCP.
+ */
+static int do_tcp_setsockopt(struct sock *sk, int level,
+ int optname, char __user *optval, unsigned int optlen)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ int val;
+ int err = 0;
+
+ /* These are data/string values, all the others are ints */
+ switch (optname) {
+ case TCP_CONGESTION: {
+ char name[TCP_CA_NAME_MAX];
+
+ if (optlen < 1)
+ return -EINVAL;
+
+ val = strncpy_from_user(name, optval,
+ min_t(long, 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;
+ }
+ default:
+ /* fallthru */
+ break;
+ }
+
+ 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 < TCP_MIN_MSS || 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_THIN_LINEAR_TIMEOUTS:
+ if (val < 0 || val > 1)
+ err = -EINVAL;
+ else
+ tp->thin_lto = val;
+ break;
+
+ case TCP_THIN_DUPACK:
+ if (val < 0 || val > 1)
+ err = -EINVAL;
+ else {
+ tp->thin_dupack = val;
+ if (tp->thin_dupack)
+ tcp_disable_early_retrans(tp);
+ }
+ break;
+
+ case TCP_REPAIR:
+ if (!tcp_can_repair_sock(sk))
+ err = -EPERM;
+ else if (val == 1) {
+ tp->repair = 1;
+ sk->sk_reuse = SK_FORCE_REUSE;
+ tp->repair_queue = TCP_NO_QUEUE;
+ } else if (val == 0) {
+ tp->repair = 0;
+ sk->sk_reuse = SK_NO_REUSE;
+ tcp_send_window_probe(sk);
+ } else
+ err = -EINVAL;
+
+ break;
+
+ case TCP_REPAIR_QUEUE:
+ if (!tp->repair)
+ err = -EPERM;
+ else if (val < TCP_QUEUES_NR)
+ tp->repair_queue = val;
+ else
+ err = -EINVAL;
+ break;
+
+ case TCP_QUEUE_SEQ:
+ if (sk->sk_state != TCP_CLOSE)
+ err = -EPERM;
+ else if (tp->repair_queue == TCP_SEND_QUEUE)
+ tp->write_seq = val;
+ else if (tp->repair_queue == TCP_RECV_QUEUE)
+ tp->rcv_nxt = val;
+ else
+ err = -EINVAL;
+ break;
+
+ case TCP_REPAIR_OPTIONS:
+ if (!tp->repair)
+ err = -EINVAL;
+ else if (sk->sk_state == TCP_ESTABLISHED)
+ err = tcp_repair_options_est(tp,
+ (struct tcp_repair_opt __user *)optval,
+ optlen);
+ else
+ err = -EPERM;
+ 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 = keepalive_time_elapsed(tp);
+ 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:
+ /* Translate value in seconds to number of retransmits */
+ icsk->icsk_accept_queue.rskq_defer_accept =
+ secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
+ TCP_RTO_MAX / HZ);
+ 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
+ case TCP_USER_TIMEOUT:
+ /* Cap the max time in ms TCP will retry or probe the window
+ * before giving up and aborting (ETIMEDOUT) a connection.
+ */
+ if (val < 0)
+ err = -EINVAL;
+ else
+ icsk->icsk_user_timeout = msecs_to_jiffies(val);
+ break;
+
+ case TCP_FASTOPEN:
+ if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
+ TCPF_LISTEN))) {
+ tcp_fastopen_init_key_once(true);
+
+ err = fastopen_init_queue(sk, val);
+ } else {
+ err = -EINVAL;
+ }
+ break;
+ case TCP_TIMESTAMP:
+ if (!tp->repair)
+ err = -EPERM;
+ else
+ tp->tsoffset = val - tcp_time_stamp;
+ break;
+ case TCP_NOTSENT_LOWAT:
+ tp->notsent_lowat = val;
+ sk->sk_write_space(sk);
+ break;
+ default:
+ err = -ENOPROTOOPT;
+ break;
+ }
+
+ release_sock(sk);
+ return err;
+}
+
+int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
+ unsigned int optlen)
+{
+ const 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);
+}
+EXPORT_SYMBOL(tcp_setsockopt);
+
+#ifdef CONFIG_COMPAT
+int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
+ char __user *optval, unsigned 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)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ const struct inet_connection_sock *icsk = inet_csk(sk);
+ u32 now = tcp_time_stamp;
+ unsigned int start;
+ u32 rate;
+
+ 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;
+ if (tp->ecn_flags & TCP_ECN_SEEN)
+ info->tcpi_options |= TCPI_OPT_ECN_SEEN;
+ if (tp->syn_data_acked)
+ info->tcpi_options |= TCPI_OPT_SYN_DATA;
+
+ 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 = tp->srtt_us >> 3;
+ info->tcpi_rttvar = tp->mdev_us >> 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;
+
+ rate = READ_ONCE(sk->sk_pacing_rate);
+ info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;
+
+ rate = READ_ONCE(sk->sk_max_pacing_rate);
+ info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
+
+ do {
+ start = u64_stats_fetch_begin_irq(&tp->syncp);
+ info->tcpi_bytes_acked = tp->bytes_acked;
+ info->tcpi_bytes_received = tp->bytes_received;
+ } while (u64_stats_fetch_retry_irq(&tp->syncp, start));
+}
+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;
+ if (tp->repair)
+ val = tp->rx_opt.mss_clamp;
+ 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 = keepalive_time_when(tp) / HZ;
+ break;
+ case TCP_KEEPINTVL:
+ val = keepalive_intvl_when(tp) / HZ;
+ break;
+ case TCP_KEEPCNT:
+ val = keepalive_probes(tp);
+ 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 = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
+ TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
+ 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_CC_INFO: {
+ const struct tcp_congestion_ops *ca_ops;
+ union tcp_cc_info info;
+ size_t sz = 0;
+ int attr;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+
+ ca_ops = icsk->icsk_ca_ops;
+ if (ca_ops && ca_ops->get_info)
+ sz = ca_ops->get_info(sk, ~0U, &attr, &info);
+
+ len = min_t(unsigned int, len, sz);
+ 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;
+
+ case TCP_THIN_LINEAR_TIMEOUTS:
+ val = tp->thin_lto;
+ break;
+ case TCP_THIN_DUPACK:
+ val = tp->thin_dupack;
+ break;
+
+ case TCP_REPAIR:
+ val = tp->repair;
+ break;
+
+ case TCP_REPAIR_QUEUE:
+ if (tp->repair)
+ val = tp->repair_queue;
+ else
+ return -EINVAL;
+ break;
+
+ case TCP_QUEUE_SEQ:
+ if (tp->repair_queue == TCP_SEND_QUEUE)
+ val = tp->write_seq;
+ else if (tp->repair_queue == TCP_RECV_QUEUE)
+ val = tp->rcv_nxt;
+ else
+ return -EINVAL;
+ break;
+
+ case TCP_USER_TIMEOUT:
+ val = jiffies_to_msecs(icsk->icsk_user_timeout);
+ break;
+
+ case TCP_FASTOPEN:
+ if (icsk->icsk_accept_queue.fastopenq)
+ val = icsk->icsk_accept_queue.fastopenq->max_qlen;
+ else
+ val = 0;
+ break;
+
+ case TCP_TIMESTAMP:
+ val = tcp_time_stamp + tp->tsoffset;
+ break;
+ case TCP_NOTSENT_LOWAT:
+ val = tp->notsent_lowat;
+ break;
+ 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);
+}
+EXPORT_SYMBOL(tcp_getsockopt);
+
+#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
+
+#ifdef CONFIG_TCP_MD5SIG
+static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
+static DEFINE_MUTEX(tcp_md5sig_mutex);
+static bool tcp_md5sig_pool_populated = false;
+
+static void __tcp_alloc_md5sig_pool(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
+ struct crypto_hash *hash;
+
+ hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR_OR_NULL(hash))
+ return;
+ per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
+ }
+ }
+ /* before setting tcp_md5sig_pool_populated, we must commit all writes
+ * to memory. See smp_rmb() in tcp_get_md5sig_pool()
+ */
+ smp_wmb();
+ tcp_md5sig_pool_populated = true;
+}
+
+bool tcp_alloc_md5sig_pool(void)
+{
+ if (unlikely(!tcp_md5sig_pool_populated)) {
+ mutex_lock(&tcp_md5sig_mutex);
+
+ if (!tcp_md5sig_pool_populated)
+ __tcp_alloc_md5sig_pool();
+
+ mutex_unlock(&tcp_md5sig_mutex);
+ }
+ return tcp_md5sig_pool_populated;
+}
+EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
+
+
+/**
+ * tcp_get_md5sig_pool - get md5sig_pool for this user
+ *
+ * We use percpu structure, so if we succeed, we exit with preemption
+ * and BH disabled, to make sure another thread or softirq handling
+ * wont try to get same context.
+ */
+struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
+{
+ local_bh_disable();
+
+ if (tcp_md5sig_pool_populated) {
+ /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
+ smp_rmb();
+ return this_cpu_ptr(&tcp_md5sig_pool);
+ }
+ local_bh_enable();
+ return NULL;
+}
+EXPORT_SYMBOL(tcp_get_md5sig_pool);
+
+int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
+ const struct tcphdr *th)
+{
+ struct scatterlist sg;
+ struct tcphdr hdr;
+ int err;
+
+ /* We are not allowed to change tcphdr, make a local copy */
+ memcpy(&hdr, th, sizeof(hdr));
+ hdr.check = 0;
+
+ /* options aren't included in the hash */
+ sg_init_one(&sg, &hdr, sizeof(hdr));
+ err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
+ return err;
+}
+EXPORT_SYMBOL(tcp_md5_hash_header);
+
+int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
+ const struct sk_buff *skb, unsigned int header_len)
+{
+ struct scatterlist sg;
+ const struct tcphdr *tp = tcp_hdr(skb);
+ struct hash_desc *desc = &hp->md5_desc;
+ unsigned int i;
+ const unsigned int head_data_len = skb_headlen(skb) > header_len ?
+ skb_headlen(skb) - header_len : 0;
+ const struct skb_shared_info *shi = skb_shinfo(skb);
+ struct sk_buff *frag_iter;
+
+ sg_init_table(&sg, 1);
+
+ sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
+ if (crypto_hash_update(desc, &sg, head_data_len))
+ return 1;
+
+ for (i = 0; i < shi->nr_frags; ++i) {
+ const struct skb_frag_struct *f = &shi->frags[i];
+ unsigned int offset = f->page_offset;
+ struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
+
+ sg_set_page(&sg, page, skb_frag_size(f),
+ offset_in_page(offset));
+ if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
+ return 1;
+ }
+
+ skb_walk_frags(skb, frag_iter)
+ if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
+ return 1;
+
+ return 0;
+}
+EXPORT_SYMBOL(tcp_md5_hash_skb_data);
+
+int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
+{
+ struct scatterlist sg;
+
+ sg_init_one(&sg, key->key, key->keylen);
+ return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
+}
+EXPORT_SYMBOL(tcp_md5_hash_key);
+
+#endif
+
+void tcp_done(struct sock *sk)
+{
+ struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
+
+ 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);
+ if (req)
+ reqsk_fastopen_remove(sk, req, false);
+
+ 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)
+{
+ ssize_t ret;
+
+ if (!str)
+ return 0;
+
+ ret = kstrtoul(str, 0, &thash_entries);
+ if (ret)
+ return 0;
+
+ return 1;
+}
+__setup("thash_entries=", set_thash_entries);
+
+static void __init tcp_init_mem(void)
+{
+ unsigned long limit = nr_free_buffer_pages() / 8;
+ 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;
+}
+
+void __init tcp_init(void)
+{
+ unsigned long limit;
+ int max_rshare, max_wshare, cnt;
+ unsigned int i;
+
+ sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
+
+ percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
+ percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
+ 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,
+ 17, /* one slot per 128 KB of memory */
+ 0,
+ NULL,
+ &tcp_hashinfo.ehash_mask,
+ 0,
+ thash_entries ? 0 : 512 * 1024);
+ for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
+ INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
+
+ 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_mask + 1,
+ 17, /* one slot per 128 KB of memory */
+ 0,
+ &tcp_hashinfo.bhash_size,
+ NULL,
+ 0,
+ 64 * 1024);
+ tcp_hashinfo.bhash_size = 1U << 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);
+ }
+
+
+ cnt = tcp_hashinfo.ehash_mask + 1;
+
+ tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
+ sysctl_tcp_max_orphans = cnt / 2;
+ sysctl_max_syn_backlog = max(128, cnt / 256);
+
+ tcp_init_mem();
+ /* Set per-socket limits to no more than 1/128 the pressure threshold */
+ limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
+ max_wshare = min(4UL*1024*1024, limit);
+ max_rshare = min(6UL*1024*1024, limit);
+
+ sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
+ sysctl_tcp_wmem[1] = 16*1024;
+ sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
+
+ sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
+ sysctl_tcp_rmem[1] = 87380;
+ sysctl_tcp_rmem[2] = max(87380, max_rshare);
+
+ pr_info("Hash tables configured (established %u bind %u)\n",
+ tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
+
+ tcp_metrics_init();
+ BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
+ tcp_tasklet_init();
+}
Code Review / kvmfornfv.git / blobdiff