| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * 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. |
| * |
| * 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 <crypto/hash.h> |
| #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/memblock.h> |
| #include <linux/highmem.h> |
| #include <linux/cache.h> |
| #include <linux/err.h> |
| #include <linux/time.h> |
| #include <linux/slab.h> |
| #include <linux/errqueue.h> |
| #include <linux/static_key.h> |
| #include <linux/btf.h> |
| |
| #include <net/icmp.h> |
| #include <net/inet_common.h> |
| #include <net/tcp.h> |
| #include <net/mptcp.h> |
| #include <net/xfrm.h> |
| #include <net/ip.h> |
| #include <net/sock.h> |
| |
| #include <linux/uaccess.h> |
| #include <asm/ioctls.h> |
| #include <net/busy_poll.h> |
| |
| /* Track pending CMSGs. */ |
| enum { |
| TCP_CMSG_INQ = 1, |
| TCP_CMSG_TS = 2 |
| }; |
| |
| DEFINE_PER_CPU(unsigned int, tcp_orphan_count); |
| EXPORT_PER_CPU_SYMBOL_GPL(tcp_orphan_count); |
| |
| long sysctl_tcp_mem[3] __read_mostly; |
| EXPORT_SYMBOL(sysctl_tcp_mem); |
| |
| atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp; /* Current allocated memory. */ |
| EXPORT_SYMBOL(tcp_memory_allocated); |
| DEFINE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); |
| EXPORT_PER_CPU_SYMBOL_GPL(tcp_memory_per_cpu_fw_alloc); |
| |
| #if IS_ENABLED(CONFIG_SMC) |
| DEFINE_STATIC_KEY_FALSE(tcp_have_smc); |
| EXPORT_SYMBOL(tcp_have_smc); |
| #endif |
| |
| /* |
| * Current number of TCP sockets. |
| */ |
| struct percpu_counter tcp_sockets_allocated ____cacheline_aligned_in_smp; |
| 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. |
| */ |
| unsigned long tcp_memory_pressure __read_mostly; |
| EXPORT_SYMBOL_GPL(tcp_memory_pressure); |
| |
| void tcp_enter_memory_pressure(struct sock *sk) |
| { |
| unsigned long val; |
| |
| if (READ_ONCE(tcp_memory_pressure)) |
| return; |
| val = jiffies; |
| |
| if (!val) |
| val--; |
| if (!cmpxchg(&tcp_memory_pressure, 0, val)) |
| NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); |
| } |
| EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure); |
| |
| void tcp_leave_memory_pressure(struct sock *sk) |
| { |
| unsigned long val; |
| |
| if (!READ_ONCE(tcp_memory_pressure)) |
| return; |
| val = xchg(&tcp_memory_pressure, 0); |
| if (val) |
| NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO, |
| jiffies_to_msecs(jiffies - val)); |
| } |
| EXPORT_SYMBOL_GPL(tcp_leave_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; |
| } |
| |
| static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp) |
| { |
| u32 rate = READ_ONCE(tp->rate_delivered); |
| u32 intv = READ_ONCE(tp->rate_interval_us); |
| u64 rate64 = 0; |
| |
| if (rate && intv) { |
| rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC; |
| do_div(rate64, intv); |
| } |
| return rate64; |
| } |
| |
| /* 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); |
| |
| tp->out_of_order_queue = RB_ROOT; |
| sk->tcp_rtx_queue = RB_ROOT; |
| tcp_init_xmit_timers(sk); |
| INIT_LIST_HEAD(&tp->tsq_node); |
| INIT_LIST_HEAD(&tp->tsorted_sent_queue); |
| |
| icsk->icsk_rto = TCP_TIMEOUT_INIT; |
| icsk->icsk_rto_min = TCP_RTO_MIN; |
| icsk->icsk_delack_max = TCP_DELACK_MAX; |
| tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); |
| minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U); |
| |
| /* 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 |
| */ |
| tcp_snd_cwnd_set(tp, TCP_INIT_CWND); |
| |
| /* There's a bubble in the pipe until at least the first ACK. */ |
| tp->app_limited = ~0U; |
| tp->rate_app_limited = 1; |
| |
| /* 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; |
| |
| tp->reordering = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering); |
| tcp_assign_congestion_control(sk); |
| |
| tp->tsoffset = 0; |
| tp->rack.reo_wnd_steps = 1; |
| |
| sk->sk_write_space = sk_stream_write_space; |
| sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); |
| |
| icsk->icsk_sync_mss = tcp_sync_mss; |
| |
| WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1])); |
| WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1])); |
| |
| set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags); |
| sk_sockets_allocated_inc(sk); |
| } |
| EXPORT_SYMBOL(tcp_init_sock); |
| |
| static void tcp_tx_timestamp(struct sock *sk, u16 tsflags) |
| { |
| struct sk_buff *skb = tcp_write_queue_tail(sk); |
| |
| if (tsflags && skb) { |
| struct skb_shared_info *shinfo = skb_shinfo(skb); |
| struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); |
| |
| sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags); |
| if (tsflags & SOF_TIMESTAMPING_TX_ACK) |
| tcb->txstamp_ack = 1; |
| if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK) |
| shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; |
| } |
| } |
| |
| static bool tcp_stream_is_readable(struct sock *sk, int target) |
| { |
| if (tcp_epollin_ready(sk, target)) |
| return true; |
| return sk_is_readable(sk); |
| } |
| |
| /* |
| * 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. |
| */ |
| __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait) |
| { |
| __poll_t mask; |
| struct sock *sk = sock->sk; |
| const struct tcp_sock *tp = tcp_sk(sk); |
| u8 shutdown; |
| int state; |
| |
| sock_poll_wait(file, sock, wait); |
| |
| state = inet_sk_state_load(sk); |
| if (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; |
| |
| /* |
| * EPOLLHUP 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 EPOLLHUP is incompatible |
| * with the EPOLLOUT/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. EPOLLHUP 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 EPOLLHUP |
| * 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 EPOLLHUP were maskable, |
| * then we could set it on SND_SHUTDOWN. BTW examples given |
| * in Stevens' books assume exactly this behaviour, it explains |
| * why EPOLLHUP is incompatible with EPOLLOUT. --ANK |
| * |
| * NOTE. Check for TCP_CLOSE is added. The goal is to prevent |
| * blocking on fresh not-connected or disconnected socket. --ANK |
| */ |
| shutdown = READ_ONCE(sk->sk_shutdown); |
| if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) |
| mask |= EPOLLHUP; |
| if (shutdown & RCV_SHUTDOWN) |
| mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; |
| |
| /* Connected or passive Fast Open socket? */ |
| if (state != TCP_SYN_SENT && |
| (state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) { |
| int target = sock_rcvlowat(sk, 0, INT_MAX); |
| u16 urg_data = READ_ONCE(tp->urg_data); |
| |
| if (unlikely(urg_data) && |
| READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) && |
| !sock_flag(sk, SOCK_URGINLINE)) |
| target++; |
| |
| if (tcp_stream_is_readable(sk, target)) |
| mask |= EPOLLIN | EPOLLRDNORM; |
| |
| if (!(shutdown & SEND_SHUTDOWN)) { |
| if (__sk_stream_is_writeable(sk, 1)) { |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| } else { /* send SIGIO later */ |
| sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); |
| 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, 1)) |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| } |
| } else |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| |
| if (urg_data & TCP_URG_VALID) |
| mask |= EPOLLPRI; |
| } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) { |
| /* Active TCP fastopen socket with defer_connect |
| * Return EPOLLOUT so application can call write() |
| * in order for kernel to generate SYN+data |
| */ |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| } |
| /* This barrier is coupled with smp_wmb() in tcp_reset() */ |
| smp_rmb(); |
| if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue)) |
| mask |= EPOLLERR; |
| |
| 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); |
| answ = tcp_inq(sk); |
| unlock_sock_fast(sk, slow); |
| break; |
| case SIOCATMARK: |
| answ = READ_ONCE(tp->urg_data) && |
| READ_ONCE(tp->urg_seq) == READ_ONCE(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 = READ_ONCE(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 = READ_ONCE(tp->write_seq) - |
| READ_ONCE(tp->snd_nxt); |
| break; |
| default: |
| return -ENOIOCTLCMD; |
| } |
| |
| return put_user(answ, (int __user *)arg); |
| } |
| EXPORT_SYMBOL(tcp_ioctl); |
| |
| 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)); |
| } |
| |
| void tcp_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); |
| |
| tcb->seq = tcb->end_seq = tp->write_seq; |
| tcb->tcp_flags = TCPHDR_ACK; |
| __skb_header_release(skb); |
| tcp_add_write_queue_tail(sk, skb); |
| sk_wmem_queued_add(sk, skb->truesize); |
| sk_mem_charge(sk, skb->truesize); |
| if (tp->nonagle & TCP_NAGLE_PUSH) |
| tp->nonagle &= ~TCP_NAGLE_PUSH; |
| |
| tcp_slow_start_after_idle_check(sk); |
| } |
| |
| 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 && |
| READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_autocorking) && |
| !tcp_rtx_queue_empty(sk) && |
| refcount_read(&sk->sk_wmem_alloc) > skb->truesize && |
| tcp_skb_can_collapse_to(skb); |
| } |
| |
| 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; |
| |
| skb = tcp_write_queue_tail(sk); |
| if (!skb) |
| return; |
| 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, &sk->sk_tsq_flags)) { |
| NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); |
| set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags); |
| } |
| /* It is possible TX completion already happened |
| * before we set TSQ_THROTTLED. |
| */ |
| if (refcount_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, skb->sk, 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. |
| */ |
| ret = -ENOTCONN; |
| break; |
| } |
| if (!timeo) { |
| ret = -EAGAIN; |
| break; |
| } |
| /* if __tcp_splice_read() got nothing while we have |
| * an skb in receive queue, we do not want to loop. |
| * This might happen with URG data. |
| */ |
| if (!skb_queue_empty(&sk->sk_receive_queue)) |
| break; |
| sk_wait_data(sk, &timeo, NULL); |
| 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 *tcp_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp, |
| bool force_schedule) |
| { |
| struct sk_buff *skb; |
| |
| skb = alloc_skb_fclone(size + MAX_TCP_HEADER, gfp); |
| if (likely(skb)) { |
| bool mem_scheduled; |
| |
| skb->truesize = SKB_TRUESIZE(skb_end_offset(skb)); |
| if (force_schedule) { |
| mem_scheduled = true; |
| sk_forced_mem_schedule(sk, skb->truesize); |
| } else { |
| mem_scheduled = sk_wmem_schedule(sk, skb->truesize); |
| } |
| if (likely(mem_scheduled)) { |
| skb_reserve(skb, MAX_TCP_HEADER); |
| skb->ip_summed = CHECKSUM_PARTIAL; |
| INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); |
| 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) |
| return mss_now; |
| |
| /* Note : tcp_tso_autosize() will eventually split this later */ |
| new_size_goal = tcp_bound_to_half_wnd(tp, sk->sk_gso_max_size); |
| |
| /* 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); |
| } |
| |
| 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; |
| } |
| |
| /* In some cases, both sendpage() and sendmsg() could have added |
| * an skb to the write queue, but failed adding payload on it. |
| * We need to remove it to consume less memory, but more |
| * importantly be able to generate EPOLLOUT for Edge Trigger epoll() |
| * users. |
| */ |
| void tcp_remove_empty_skb(struct sock *sk) |
| { |
| struct sk_buff *skb = tcp_write_queue_tail(sk); |
| |
| if (skb && TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { |
| tcp_unlink_write_queue(skb, sk); |
| if (tcp_write_queue_empty(sk)) |
| tcp_chrono_stop(sk, TCP_CHRONO_BUSY); |
| tcp_wmem_free_skb(sk, skb); |
| } |
| } |
| |
| /* skb changing from pure zc to mixed, must charge zc */ |
| static int tcp_downgrade_zcopy_pure(struct sock *sk, struct sk_buff *skb) |
| { |
| if (unlikely(skb_zcopy_pure(skb))) { |
| u32 extra = skb->truesize - |
| SKB_TRUESIZE(skb_end_offset(skb)); |
| |
| if (!sk_wmem_schedule(sk, extra)) |
| return -ENOMEM; |
| |
| sk_mem_charge(sk, extra); |
| skb_shinfo(skb)->flags &= ~SKBFL_PURE_ZEROCOPY; |
| } |
| return 0; |
| } |
| |
| |
| static int tcp_wmem_schedule(struct sock *sk, int copy) |
| { |
| int left; |
| |
| if (likely(sk_wmem_schedule(sk, copy))) |
| return copy; |
| |
| /* We could be in trouble if we have nothing queued. |
| * Use whatever is left in sk->sk_forward_alloc and tcp_wmem[0] |
| * to guarantee some progress. |
| */ |
| left = sock_net(sk)->ipv4.sysctl_tcp_wmem[0] - sk->sk_wmem_queued; |
| if (left > 0) |
| sk_forced_mem_schedule(sk, min(left, copy)); |
| return min(copy, sk->sk_forward_alloc); |
| } |
| |
| static struct sk_buff *tcp_build_frag(struct sock *sk, int size_goal, int flags, |
| struct page *page, int offset, size_t *size) |
| { |
| struct sk_buff *skb = tcp_write_queue_tail(sk); |
| struct tcp_sock *tp = tcp_sk(sk); |
| bool can_coalesce; |
| int copy, i; |
| |
| if (!skb || (copy = size_goal - skb->len) <= 0 || |
| !tcp_skb_can_collapse_to(skb)) { |
| new_segment: |
| if (!sk_stream_memory_free(sk)) |
| return NULL; |
| |
| skb = tcp_stream_alloc_skb(sk, 0, sk->sk_allocation, |
| tcp_rtx_and_write_queues_empty(sk)); |
| if (!skb) |
| return NULL; |
| |
| #ifdef CONFIG_TLS_DEVICE |
| skb->decrypted = !!(flags & MSG_SENDPAGE_DECRYPTED); |
| #endif |
| tcp_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 >= READ_ONCE(sysctl_max_skb_frags)) { |
| tcp_mark_push(tp, skb); |
| goto new_segment; |
| } |
| if (tcp_downgrade_zcopy_pure(sk, skb)) |
| return NULL; |
| |
| copy = tcp_wmem_schedule(sk, copy); |
| if (!copy) |
| return NULL; |
| |
| if (can_coalesce) { |
| skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); |
| } else { |
| get_page(page); |
| skb_fill_page_desc_noacc(skb, i, page, offset, copy); |
| } |
| |
| if (!(flags & MSG_NO_SHARED_FRAGS)) |
| skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG; |
| |
| skb->len += copy; |
| skb->data_len += copy; |
| skb->truesize += copy; |
| sk_wmem_queued_add(sk, copy); |
| sk_mem_charge(sk, copy); |
| WRITE_ONCE(tp->write_seq, tp->write_seq + copy); |
| TCP_SKB_CB(skb)->end_seq += copy; |
| tcp_skb_pcount_set(skb, 0); |
| |
| *size = copy; |
| return skb; |
| } |
| |
| 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); |
| |
| if (IS_ENABLED(CONFIG_DEBUG_VM) && |
| WARN_ONCE(!sendpage_ok(page), |
| "page must not be a Slab one and have page_count > 0")) |
| return -EINVAL; |
| |
| /* 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)) { |
| err = sk_stream_wait_connect(sk, &timeo); |
| if (err != 0) |
| goto out_err; |
| } |
| |
| sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); |
| |
| 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; |
| size_t copy = size; |
| |
| skb = tcp_build_frag(sk, size_goal, flags, page, offset, ©); |
| if (!skb) |
| goto wait_for_space; |
| |
| if (!copied) |
| TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; |
| |
| copied += copy; |
| offset += copy; |
| size -= copy; |
| if (!size) |
| 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_space: |
| set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); |
| tcp_push(sk, flags & ~MSG_MORE, mss_now, |
| TCP_NAGLE_PUSH, size_goal); |
| |
| err = sk_stream_wait_memory(sk, &timeo); |
| if (err != 0) |
| goto do_error; |
| |
| mss_now = tcp_send_mss(sk, &size_goal, flags); |
| } |
| |
| out: |
| if (copied) { |
| tcp_tx_timestamp(sk, sk->sk_tsflags); |
| if (!(flags & MSG_SENDPAGE_NOTLAST)) |
| tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); |
| } |
| return copied; |
| |
| do_error: |
| tcp_remove_empty_skb(sk); |
| if (copied) |
| goto out; |
| out_err: |
| /* make sure we wake any epoll edge trigger waiter */ |
| if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) { |
| sk->sk_write_space(sk); |
| tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED); |
| } |
| return sk_stream_error(sk, flags, err); |
| } |
| EXPORT_SYMBOL_GPL(do_tcp_sendpages); |
| |
| int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, |
| size_t size, int flags) |
| { |
| if (!(sk->sk_route_caps & NETIF_F_SG)) |
| return sock_no_sendpage_locked(sk, page, offset, size, flags); |
| |
| tcp_rate_check_app_limited(sk); /* is sending application-limited? */ |
| |
| return do_tcp_sendpages(sk, page, offset, size, flags); |
| } |
| EXPORT_SYMBOL_GPL(tcp_sendpage_locked); |
| |
| int tcp_sendpage(struct sock *sk, struct page *page, int offset, |
| size_t size, int flags) |
| { |
| int ret; |
| |
| lock_sock(sk); |
| ret = tcp_sendpage_locked(sk, page, offset, size, flags); |
| release_sock(sk); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(tcp_sendpage); |
| |
| void tcp_free_fastopen_req(struct tcp_sock *tp) |
| { |
| if (tp->fastopen_req) { |
| kfree(tp->fastopen_req); |
| tp->fastopen_req = NULL; |
| } |
| } |
| |
| int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, |
| size_t size, struct ubuf_info *uarg) |
| { |
| struct tcp_sock *tp = tcp_sk(sk); |
| struct inet_sock *inet = inet_sk(sk); |
| struct sockaddr *uaddr = msg->msg_name; |
| int err, flags; |
| |
| if (!(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) & |
| TFO_CLIENT_ENABLE) || |
| (uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) && |
| uaddr->sa_family == AF_UNSPEC)) |
| 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; |
| tp->fastopen_req->uarg = uarg; |
| |
| if (inet->defer_connect) { |
| err = tcp_connect(sk); |
| /* Same failure procedure as in tcp_v4/6_connect */ |
| if (err) { |
| tcp_set_state(sk, TCP_CLOSE); |
| inet->inet_dport = 0; |
| sk->sk_route_caps = 0; |
| } |
| } |
| flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; |
| err = __inet_stream_connect(sk->sk_socket, uaddr, |
| msg->msg_namelen, flags, 1); |
| /* fastopen_req could already be freed in __inet_stream_connect |
| * if the connection times out or gets rst |
| */ |
| if (tp->fastopen_req) { |
| *copied = tp->fastopen_req->copied; |
| tcp_free_fastopen_req(tp); |
| inet->defer_connect = 0; |
| } |
| return err; |
| } |
| |
| int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) |
| { |
| struct tcp_sock *tp = tcp_sk(sk); |
| struct ubuf_info *uarg = NULL; |
| struct sk_buff *skb; |
| struct sockcm_cookie sockc; |
| int flags, err, copied = 0; |
| int mss_now = 0, size_goal, copied_syn = 0; |
| int process_backlog = 0; |
| bool zc = false; |
| long timeo; |
| |
| flags = msg->msg_flags; |
| |
| if ((flags & MSG_ZEROCOPY) && size) { |
| skb = tcp_write_queue_tail(sk); |
| |
| if (msg->msg_ubuf) { |
| uarg = msg->msg_ubuf; |
| net_zcopy_get(uarg); |
| zc = sk->sk_route_caps & NETIF_F_SG; |
| } else if (sock_flag(sk, SOCK_ZEROCOPY)) { |
| uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb)); |
| if (!uarg) { |
| err = -ENOBUFS; |
| goto out_err; |
| } |
| zc = sk->sk_route_caps & NETIF_F_SG; |
| if (!zc) |
| uarg_to_msgzc(uarg)->zerocopy = 0; |
| } |
| } |
| |
| if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) && |
| !tp->repair) { |
| err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size, uarg); |
| if (err == -EINPROGRESS && copied_syn > 0) |
| goto out; |
| else if (err) |
| goto out_err; |
| } |
| |
| timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); |
| |
| tcp_rate_check_app_limited(sk); /* is sending application-limited? */ |
| |
| /* 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)) { |
| err = sk_stream_wait_connect(sk, &timeo); |
| if (err != 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 */ |
| } |
| |
| sockcm_init(&sockc, sk); |
| if (msg->msg_controllen) { |
| err = sock_cmsg_send(sk, msg, &sockc); |
| if (unlikely(err)) { |
| err = -EINVAL; |
| goto out_err; |
| } |
| } |
| |
| /* This should be in poll */ |
| sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); |
| |
| /* Ok commence sending. */ |
| copied = 0; |
| |
| restart: |
| mss_now = tcp_send_mss(sk, &size_goal, flags); |
| |
| err = -EPIPE; |
| if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) |
| goto do_error; |
| |
| while (msg_data_left(msg)) { |
| int copy = 0; |
| |
| skb = tcp_write_queue_tail(sk); |
| if (skb) |
| copy = size_goal - skb->len; |
| |
| if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) { |
| bool first_skb; |
| |
| new_segment: |
| if (!sk_stream_memory_free(sk)) |
| goto wait_for_space; |
| |
| if (unlikely(process_backlog >= 16)) { |
| process_backlog = 0; |
| if (sk_flush_backlog(sk)) |
| goto restart; |
| } |
| first_skb = tcp_rtx_and_write_queues_empty(sk); |
| skb = tcp_stream_alloc_skb(sk, 0, sk->sk_allocation, |
| first_skb); |
| if (!skb) |
| goto wait_for_space; |
| |
| process_backlog++; |
| |
| tcp_skb_entail(sk, skb); |
| copy = size_goal; |
| |
| /* All packets are restored as if they have |
| * already been sent. skb_mstamp_ns 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); |
| |
| if (!zc) { |
| 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_space; |
| |
| if (!skb_can_coalesce(skb, i, pfrag->page, |
| pfrag->offset)) { |
| if (i >= READ_ONCE(sysctl_max_skb_frags)) { |
| tcp_mark_push(tp, skb); |
| goto new_segment; |
| } |
| merge = false; |
| } |
| |
| copy = min_t(int, copy, pfrag->size - pfrag->offset); |
| |
| if (unlikely(skb_zcopy_pure(skb) || skb_zcopy_managed(skb))) { |
| if (tcp_downgrade_zcopy_pure(sk, skb)) |
| goto wait_for_space; |
| skb_zcopy_downgrade_managed(skb); |
| } |
| |
| copy = tcp_wmem_schedule(sk, copy); |
| if (!copy) |
| goto wait_for_space; |
| |
| 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); |
| page_ref_inc(pfrag->page); |
| } |
| pfrag->offset += copy; |
| } else { |
| /* First append to a fragless skb builds initial |
| * pure zerocopy skb |
| */ |
| if (!skb->len) |
| skb_shinfo(skb)->flags |= SKBFL_PURE_ZEROCOPY; |
| |
| if (!skb_zcopy_pure(skb)) { |
| copy = tcp_wmem_schedule(sk, copy); |
| if (!copy) |
| goto wait_for_space; |
| } |
| |
| err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg); |
| if (err == -EMSGSIZE || err == -EEXIST) { |
| tcp_mark_push(tp, skb); |
| goto new_segment; |
| } |
| if (err < 0) |
| goto do_error; |
| copy = err; |
| } |
| |
| if (!copied) |
| TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; |
| |
| WRITE_ONCE(tp->write_seq, tp->write_seq + copy); |
| TCP_SKB_CB(skb)->end_seq += copy; |
| tcp_skb_pcount_set(skb, 0); |
| |
| copied += copy; |
| if (!msg_data_left(msg)) { |
| if (unlikely(flags & MSG_EOR)) |
| TCP_SKB_CB(skb)->eor = 1; |
| goto out; |
| } |
| |
| if (skb->len < size_goal || (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_space: |
| set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); |
| if (copied) |
| tcp_push(sk, flags & ~MSG_MORE, mss_now, |
| TCP_NAGLE_PUSH, size_goal); |
| |
| err = sk_stream_wait_memory(sk, &timeo); |
| if (err != 0) |
| goto do_error; |
| |
| mss_now = tcp_send_mss(sk, &size_goal, flags); |
| } |
| |
| out: |
| if (copied) { |
| tcp_tx_timestamp(sk, sockc.tsflags); |
| tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); |
| } |
| out_nopush: |
| net_zcopy_put(uarg); |
| return copied + copied_syn; |
| |
| do_error: |
| tcp_remove_empty_skb(sk); |
| |
| if (copied + copied_syn) |
| goto out; |
| out_err: |
| net_zcopy_put_abort(uarg, true); |
| err = sk_stream_error(sk, flags, err); |
| /* make sure we wake any epoll edge trigger waiter */ |
| if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) { |
| sk->sk_write_space(sk); |
| tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED); |
| } |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(tcp_sendmsg_locked); |
| |
| int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) |
| { |
| int ret; |
| |
| lock_sock(sk); |
| ret = tcp_sendmsg_locked(sk, msg, size); |
| release_sock(sk); |
| |
| return ret; |
| } |
| 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)) |
| WRITE_ONCE(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_rbtree_walk(skb, &sk->tcp_rtx_queue) { |
| err = skb_copy_datagram_msg(skb, 0, msg, skb->len); |
| if (err) |
| return err; |
| copied += skb->len; |
| } |
| |
| 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. |
| */ |
| void __tcp_cleanup_rbuf(struct sock *sk, int copied) |
| { |
| struct tcp_sock *tp = tcp_sk(sk); |
| bool time_to_ack = false; |
| |
| if (inet_csk_ack_scheduled(sk)) { |
| const struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| if (/* 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) && |
| !inet_csk_in_pingpong_mode(sk))) && |
| !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); |
| } |
| |
| void tcp_cleanup_rbuf(struct sock *sk, int copied) |
| { |
| struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); |
| struct tcp_sock *tp = tcp_sk(sk); |
| |
| 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); |
| __tcp_cleanup_rbuf(sk, copied); |
| } |
| |
| static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb) |
| { |
| __skb_unlink(skb, &sk->sk_receive_queue); |
| if (likely(skb->destructor == sock_rfree)) { |
| sock_rfree(skb); |
| skb->destructor = NULL; |
| skb->sk = NULL; |
| return skb_attempt_defer_free(skb); |
| } |
| __kfree_skb(skb); |
| } |
| |
| 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 (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
| pr_err_once("%s: found a SYN, please report !\n", __func__); |
| 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() |
| */ |
| tcp_eat_recv_skb(sk, skb); |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL(tcp_recv_skb); |
| |
| /* |
| * 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 (unlikely(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; |
| } |
| if (WARN_ON_ONCE(used > len)) |
| 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) { |
| tcp_eat_recv_skb(sk, skb); |
| ++seq; |
| break; |
| } |
| tcp_eat_recv_skb(sk, skb); |
| if (!desc->count) |
| break; |
| WRITE_ONCE(tp->copied_seq, seq); |
| } |
| WRITE_ONCE(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); |
| |
| int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor) |
| { |
| struct tcp_sock *tp = tcp_sk(sk); |
| u32 seq = tp->copied_seq; |
| struct sk_buff *skb; |
| int copied = 0; |
| u32 offset; |
| |
| if (sk->sk_state == TCP_LISTEN) |
| return -ENOTCONN; |
| |
| while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { |
| u8 tcp_flags; |
| int used; |
| |
| __skb_unlink(skb, &sk->sk_receive_queue); |
| WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk)); |
| tcp_flags = TCP_SKB_CB(skb)->tcp_flags; |
| used = recv_actor(sk, skb); |
| if (used < 0) { |
| if (!copied) |
| copied = used; |
| break; |
| } |
| seq += used; |
| copied += used; |
| |
| if (tcp_flags & TCPHDR_FIN) { |
| ++seq; |
| break; |
| } |
| } |
| return copied; |
| } |
| EXPORT_SYMBOL(tcp_read_skb); |
| |
| void tcp_read_done(struct sock *sk, size_t len) |
| { |
| struct tcp_sock *tp = tcp_sk(sk); |
| u32 seq = tp->copied_seq; |
| struct sk_buff *skb; |
| size_t left; |
| u32 offset; |
| |
| if (sk->sk_state == TCP_LISTEN) |
| return; |
| |
| left = len; |
| while (left && (skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { |
| int used; |
| |
| used = min_t(size_t, skb->len - offset, left); |
| seq += used; |
| left -= used; |
| |
| if (skb->len > offset + used) |
| break; |
| |
| if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { |
| tcp_eat_recv_skb(sk, skb); |
| ++seq; |
| break; |
| } |
| tcp_eat_recv_skb(sk, skb); |
| } |
| WRITE_ONCE(tp->copied_seq, seq); |
| |
| tcp_rcv_space_adjust(sk); |
| |
| /* Clean up data we have read: This will do ACK frames. */ |
| if (left != len) |
| tcp_cleanup_rbuf(sk, len - left); |
| } |
| EXPORT_SYMBOL(tcp_read_done); |
| |
| int tcp_peek_len(struct socket *sock) |
| { |
| return tcp_inq(sock->sk); |
| } |
| EXPORT_SYMBOL(tcp_peek_len); |
| |
| /* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */ |
| int tcp_set_rcvlowat(struct sock *sk, int val) |
| { |
| int cap; |
| |
| if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) |
| cap = sk->sk_rcvbuf >> 1; |
| else |
| cap = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1; |
| val = min(val, cap); |
| WRITE_ONCE(sk->sk_rcvlowat, val ? : 1); |
| |
| /* Check if we need to signal EPOLLIN right now */ |
| tcp_data_ready(sk); |
| |
| if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) |
| return 0; |
| |
| val <<= 1; |
| if (val > sk->sk_rcvbuf) { |
| WRITE_ONCE(sk->sk_rcvbuf, val); |
| tcp_sk(sk)->window_clamp = tcp_win_from_space(sk, val); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(tcp_set_rcvlowat); |
| |
| void tcp_update_recv_tstamps(struct sk_buff *skb, |
| struct scm_timestamping_internal *tss) |
| { |
| if (skb->tstamp) |
| tss->ts[0] = ktime_to_timespec64(skb->tstamp); |
| else |
| tss->ts[0] = (struct timespec64) {0}; |
| |
| if (skb_hwtstamps(skb)->hwtstamp) |
| tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp); |
| else |
| tss->ts[2] = (struct timespec64) {0}; |
| } |
| |
| #ifdef CONFIG_MMU |
| static const struct vm_operations_struct tcp_vm_ops = { |
| }; |
| |
| int tcp_mmap(struct file *file, struct socket *sock, |
| struct vm_area_struct *vma) |
| { |
| if (vma->vm_flags & (VM_WRITE | VM_EXEC)) |
| return -EPERM; |
| vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); |
| |
| /* Instruct vm_insert_page() to not mmap_read_lock(mm) */ |
| vma->vm_flags |= VM_MIXEDMAP; |
| |
| vma->vm_ops = &tcp_vm_ops; |
| return 0; |
| } |
| EXPORT_SYMBOL(tcp_mmap); |
| |
| static skb_frag_t *skb_advance_to_frag(struct sk_buff *skb, u32 offset_skb, |
| u32 *offset_frag) |
| { |
| skb_frag_t *frag; |
| |
| if (unlikely(offset_skb >= skb->len)) |
| return NULL; |
| |
| offset_skb -= skb_headlen(skb); |
| if ((int)offset_skb < 0 || skb_has_frag_list(skb)) |
| return NULL; |
| |
| frag = skb_shinfo(skb)->frags; |
| while (offset_skb) { |
| if (skb_frag_size(frag) > offset_skb) { |
| *offset_frag = offset_skb; |
| return frag; |
| } |
| offset_skb -= skb_frag_size(frag); |
| ++frag; |
| } |
| *offset_frag = 0; |
| return frag; |
| } |
| |
| static bool can_map_frag(const skb_frag_t *frag) |
| { |
| return skb_frag_size(frag) == PAGE_SIZE && !skb_frag_off(frag); |
| } |
| |
| static int find_next_mappable_frag(const skb_frag_t *frag, |
| int remaining_in_skb) |
| { |
| int offset = 0; |
| |
| if (likely(can_map_frag(frag))) |
| return 0; |
| |
| while (offset < remaining_in_skb && !can_map_frag(frag)) { |
| offset += skb_frag_size(frag); |
| ++frag; |
| } |
| return offset; |
| } |
| |
| static void tcp_zerocopy_set_hint_for_skb(struct sock *sk, |
| struct tcp_zerocopy_receive *zc, |
| struct sk_buff *skb, u32 offset) |
| { |
| u32 frag_offset, partial_frag_remainder = 0; |
| int mappable_offset; |
| skb_frag_t *frag; |
| |
| /* worst case: skip to next skb. try to improve on this case below */ |
| zc->recv_skip_hint = skb->len - offset; |
| |
| /* Find the frag containing this offset (and how far into that frag) */ |
| frag = skb_advance_to_frag(skb, offset, &frag_offset); |
| if (!frag) |
| return; |
| |
| if (frag_offset) { |
| struct skb_shared_info *info = skb_shinfo(skb); |
| |
| /* We read part of the last frag, must recvmsg() rest of skb. */ |
| if (frag == &info->frags[info->nr_frags - 1]) |
| return; |
| |
| /* Else, we must at least read the remainder in this frag. */ |
| partial_frag_remainder = skb_frag_size(frag) - frag_offset; |
| zc->recv_skip_hint -= partial_frag_remainder; |
| ++frag; |
| } |
| |
| /* partial_frag_remainder: If part way through a frag, must read rest. |
| * mappable_offset: Bytes till next mappable frag, *not* counting bytes |
| * in partial_frag_remainder. |
| */ |
| mappable_offset = find_next_mappable_frag(frag, zc->recv_skip_hint); |
| zc->recv_skip_hint = mappable_offset + partial_frag_remainder; |
| } |
| |
| static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, |
| int flags, struct scm_timestamping_internal *tss, |
| int *cmsg_flags); |
| static int receive_fallback_to_copy(struct sock *sk, |
| struct tcp_zerocopy_receive *zc, int inq, |
| struct scm_timestamping_internal *tss) |
| { |
| unsigned long copy_address = (unsigned long)zc->copybuf_address; |
| struct msghdr msg = {}; |
| struct iovec iov; |
| int err; |
| |
| zc->length = 0; |
| zc->recv_skip_hint = 0; |
| |
| if (copy_address != zc->copybuf_address) |
| return -EINVAL; |
| |
| err = import_single_range(ITER_DEST, (void __user *)copy_address, |
| inq, &iov, &msg.msg_iter); |
| if (err) |
| return err; |
| |
| err = tcp_recvmsg_locked(sk, &msg, inq, MSG_DONTWAIT, |
| tss, &zc->msg_flags); |
| if (err < 0) |
| return err; |
| |
| zc->copybuf_len = err; |
| if (likely(zc->copybuf_len)) { |
| struct sk_buff *skb; |
| u32 offset; |
| |
| skb = tcp_recv_skb(sk, tcp_sk(sk)->copied_seq, &offset); |
| if (skb) |
| tcp_zerocopy_set_hint_for_skb(sk, zc, skb, offset); |
| } |
| return 0; |
| } |
| |
| static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc, |
| struct sk_buff *skb, u32 copylen, |
| u32 *offset, u32 *seq) |
| { |
| unsigned long copy_address = (unsigned long)zc->copybuf_address; |
| struct msghdr msg = {}; |
| struct iovec iov; |
| int err; |
| |
| if (copy_address != zc->copybuf_address) |
| return -EINVAL; |
| |
| err = import_single_range(ITER_DEST, (void __user *)copy_address, |
| copylen, &iov, &msg.msg_iter); |
| if (err) |
| return err; |
| err = skb_copy_datagram_msg(skb, *offset, &msg, copylen); |
| if (err) |
| return err; |
| zc->recv_skip_hint -= copylen; |
| *offset += copylen; |
| *seq += copylen; |
| return (__s32)copylen; |
| } |
| |
| static int tcp_zc_handle_leftover(struct tcp_zerocopy_receive *zc, |
| struct sock *sk, |
| struct sk_buff *skb, |
| u32 *seq, |
| s32 copybuf_len, |
| struct scm_timestamping_internal *tss) |
| { |
| u32 offset, copylen = min_t(u32, copybuf_len, zc->recv_skip_hint); |
| |
| if (!copylen) |
| return 0; |
| /* skb is null if inq < PAGE_SIZE. */ |
| if (skb) { |
| offset = *seq - TCP_SKB_CB(skb)->seq; |
| } else { |
| skb = tcp_recv_skb(sk, *seq, &offset); |
| if (TCP_SKB_CB(skb)->has_rxtstamp) { |
| tcp_update_recv_tstamps(skb, tss); |
| zc->msg_flags |= TCP_CMSG_TS; |
| } |
| } |
| |
| zc->copybuf_len = tcp_copy_straggler_data(zc, skb, copylen, &offset, |
| seq); |
| return zc->copybuf_len < 0 ? 0 : copylen; |
| } |
| |
| static int tcp_zerocopy_vm_insert_batch_error(struct vm_area_struct *vma, |
| struct page **pending_pages, |
| unsigned long pages_remaining, |
| unsigned long *address, |
| u32 *length, |
| u32 *seq, |
| struct tcp_zerocopy_receive *zc, |
| u32 total_bytes_to_map, |
| int err) |
| { |
| /* At least one page did not map. Try zapping if we skipped earlier. */ |
| if (err == -EBUSY && |
| zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT) { |
| u32 maybe_zap_len; |
| |
| maybe_zap_len = total_bytes_to_map - /* All bytes to map */ |
| *length + /* Mapped or pending */ |
| (pages_remaining * PAGE_SIZE); /* Failed map. */ |
| zap_page_range(vma, *address, maybe_zap_len); |
| err = 0; |
| } |
| |
| if (!err) { |
| unsigned long leftover_pages = pages_remaining; |
| int bytes_mapped; |
| |
| /* We called zap_page_range, try to reinsert. */ |
| err = vm_insert_pages(vma, *address, |
| pending_pages, |
| &pages_remaining); |
| bytes_mapped = PAGE_SIZE * (leftover_pages - pages_remaining); |
| *seq += bytes_mapped; |
| *address += bytes_mapped; |
| } |
| if (err) { |
| /* Either we were unable to zap, OR we zapped, retried an |
| * insert, and still had an issue. Either ways, pages_remaining |
| * is the number of pages we were unable to map, and we unroll |
| * some state we speculatively touched before. |
| */ |
| const int bytes_not_mapped = PAGE_SIZE * pages_remaining; |
| |
| *length -= bytes_not_mapped; |
| zc->recv_skip_hint += bytes_not_mapped; |
| } |
| return err; |
| } |
| |
| static int tcp_zerocopy_vm_insert_batch(struct vm_area_struct *vma, |
| struct page **pages, |
| unsigned int pages_to_map, |
| unsigned long *address, |
| u32 *length, |
| u32 *seq, |
| struct tcp_zerocopy_receive *zc, |
| u32 total_bytes_to_map) |
| { |
| unsigned long pages_remaining = pages_to_map; |
| unsigned int pages_mapped; |
| unsigned int bytes_mapped; |
| int err; |
| |
| err = vm_insert_pages(vma, *address, pages, &pages_remaining); |
| pages_mapped = pages_to_map - (unsigned int)pages_remaining; |
| bytes_mapped = PAGE_SIZE * pages_mapped; |
| /* Even if vm_insert_pages fails, it may have partially succeeded in |
| * mapping (some but not all of the pages). |
| */ |
| *seq += bytes_mapped; |
| *address += bytes_mapped; |
| |
| if (likely(!err)) |
| return 0; |
| |
| /* Error: maybe zap and retry + rollback state for failed inserts. */ |
| return tcp_zerocopy_vm_insert_batch_error(vma, pages + pages_mapped, |
| pages_remaining, address, length, seq, zc, total_bytes_to_map, |
| err); |
| } |
| |
| #define TCP_VALID_ZC_MSG_FLAGS (TCP_CMSG_TS) |
| static void tcp_zc_finalize_rx_tstamp(struct sock *sk, |
| struct tcp_zerocopy_receive *zc, |
| struct scm_timestamping_internal *tss) |
| { |
| unsigned long msg_control_addr; |
| struct msghdr cmsg_dummy; |
| |
| msg_control_addr = (unsigned long)zc->msg_control; |
| cmsg_dummy.msg_control = (void *)msg_control_addr; |
| cmsg_dummy.msg_controllen = |
| (__kernel_size_t)zc->msg_controllen; |
| cmsg_dummy.msg_flags = in_compat_syscall() |
| ? MSG_CMSG_COMPAT : 0; |
| cmsg_dummy.msg_control_is_user = true; |
| zc->msg_flags = 0; |
| if (zc->msg_control == msg_control_addr && |
| zc->msg_controllen == cmsg_dummy.msg_controllen) { |
| tcp_recv_timestamp(&cmsg_dummy, sk, tss); |
| zc->msg_control = (__u64) |
| ((uintptr_t)cmsg_dummy.msg_control); |
| zc->msg_controllen = |
| (__u64)cmsg_dummy.msg_controllen; |
| zc->msg_flags = (__u32)cmsg_dummy.msg_flags; |
| } |
| } |
| |
| #define TCP_ZEROCOPY_PAGE_BATCH_SIZE 32 |
| static int tcp_zerocopy_receive(struct sock *sk, |
| struct tcp_zerocopy_receive *zc, |
| struct scm_timestamping_internal *tss) |
| { |
| u32 length = 0, offset, vma_len, avail_len, copylen = 0; |
| unsigned long address = (unsigned long)zc->address; |
| struct page *pages[TCP_ZEROCOPY_PAGE_BATCH_SIZE]; |
| s32 copybuf_len = zc->copybuf_len; |
| struct tcp_sock *tp = tcp_sk(sk); |
| const skb_frag_t *frags = NULL; |
| unsigned int pages_to_map = 0; |
| struct vm_area_struct *vma; |
| struct sk_buff *skb = NULL; |
| u32 seq = tp->copied_seq; |
| u32 total_bytes_to_map; |
| int inq = tcp_inq(sk); |
| int ret; |
| |
| zc->copybuf_len = 0; |
| zc->msg_flags = 0; |
| |
| if (address & (PAGE_SIZE - 1) || address != zc->address) |
| return -EINVAL; |
| |
| if (sk->sk_state == TCP_LISTEN) |
| return -ENOTCONN; |
| |
| sock_rps_record_flow(sk); |
| |
| if (inq && inq <= copybuf_len) |
| return receive_fallback_to_copy(sk, zc, inq, tss); |
| |
| if (inq < PAGE_SIZE) { |
| zc->length = 0; |
| zc->recv_skip_hint = inq; |
| if (!inq && sock_flag(sk, SOCK_DONE)) |
| return -EIO; |
| return 0; |
| } |
| |
| mmap_read_lock(current->mm); |
| |
| vma = vma_lookup(current->mm, address); |
| if (!vma || vma->vm_ops != &tcp_vm_ops) { |
| mmap_read_unlock(current->mm); |
| return -EINVAL; |
| } |
| vma_len = min_t(unsigned long, zc->length, vma->vm_end - address); |
| avail_len = min_t(u32, vma_len, inq); |
| total_bytes_to_map = avail_len & ~(PAGE_SIZE - 1); |
| if (total_bytes_to_map) { |
| if (!(zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT)) |
| zap_page_range(vma, address, total_bytes_to_map); |
| zc->length = total_bytes_to_map; |
| zc->recv_skip_hint = 0; |
| } else { |
| zc->length = avail_len; |
| zc->recv_skip_hint = avail_len; |
| } |
| ret = 0; |
| while (length + PAGE_SIZE <= zc->length) { |
| int mappable_offset; |
| struct page *page; |
| |
| if (zc->recv_skip_hint < PAGE_SIZE) { |
| u32 offset_frag; |
| |
| if (skb) { |
| if (zc->recv_skip_hint > 0) |
| break; |
| skb = skb->next; |
| offset = seq - TCP_SKB_CB(skb)->seq; |
| } else { |
| skb = tcp_recv_skb(sk, seq, &offset); |
| } |
| |
| if (TCP_SKB_CB(skb)->has_rxtstamp) { |
| tcp_update_recv_tstamps(skb, tss); |
| zc->msg_flags |= TCP_CMSG_TS; |
| } |
| zc->recv_skip_hint = skb->len - offset; |
| frags = skb_advance_to_frag(skb, offset, &offset_frag); |
| if (!frags || offset_frag) |
| break; |
| } |
| |
| mappable_offset = find_next_mappable_frag(frags, |
| zc->recv_skip_hint); |
| if (mappable_offset) { |
| zc->recv_skip_hint = mappable_offset; |
| break; |
| } |
| page = skb_frag_page(frags); |
| prefetchw(page); |
| pages[pages_to_map++] = page; |
| length += PAGE_SIZE; |
| zc->recv_skip_hint -= PAGE_SIZE; |
| frags++; |
| if (pages_to_map == TCP_ZEROCOPY_PAGE_BATCH_SIZE || |
| zc->recv_skip_hint < PAGE_SIZE) { |
| /* Either full batch, or we're about to go to next skb |
| * (and we cannot unroll failed ops across skbs). |
| */ |
| ret = tcp_zerocopy_vm_insert_batch(vma, pages, |
| pages_to_map, |
| &address, &length, |
| &seq, zc, |
| total_bytes_to_map); |
| if (ret) |
| goto out; |
| pages_to_map = 0; |
| } |
| } |
| if (pages_to_map) { |
| ret = tcp_zerocopy_vm_insert_batch(vma, pages, pages_to_map, |
| &address, &length, &seq, |
| zc, total_bytes_to_map); |
| } |
| out: |
| mmap_read_unlock(current->mm); |
| /* Try to copy straggler data. */ |
| if (!ret) |
| copylen = tcp_zc_handle_leftover(zc, sk, skb, &seq, copybuf_len, tss); |
| |
| if (length + copylen) { |
| WRITE_ONCE(tp->copied_seq, seq); |
| tcp_rcv_space_adjust(sk); |
| |
| /* Clean up data we have read: This will do ACK frames. */ |
| tcp_recv_skb(sk, seq, &offset); |
| tcp_cleanup_rbuf(sk, length + copylen); |
| ret = 0; |
| if (length == zc->length) |
| zc->recv_skip_hint = 0; |
| } else { |
| if (!zc->recv_skip_hint && sock_flag(sk, SOCK_DONE)) |
| ret = -EIO; |
| } |
| zc->length = length; |
| return ret; |
| } |
| #endif |
| |
| /* Similar to __sock_recv_timestamp, but does not require an skb */ |
| void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, |
| struct scm_timestamping_internal *tss) |
| { |
| int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW); |
| bool has_timestamping = false; |
| |
| if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) { |
| if (sock_flag(sk, SOCK_RCVTSTAMP)) { |
| if (sock_flag(sk, SOCK_RCVTSTAMPNS)) { |
| if (new_tstamp) { |
| struct __kernel_timespec kts = { |
| .tv_sec = tss->ts[0].tv_sec, |
| .tv_nsec = tss->ts[0].tv_nsec, |
| }; |
| put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_NEW, |
| sizeof(kts), &kts); |
| } else { |
| struct __kernel_old_timespec ts_old = { |
| .tv_sec = tss->ts[0].tv_sec, |
| .tv_nsec = tss->ts[0].tv_nsec, |
| }; |
| put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_OLD, |
| sizeof(ts_old), &ts_old); |
| } |
| } else { |
| if (new_tstamp) { |
| struct __kernel_sock_timeval stv = { |
| .tv_sec = tss->ts[0].tv_sec, |
| .tv_usec = tss->ts[0].tv_nsec / 1000, |
| }; |
| put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_NEW, |
| sizeof(stv), &stv); |
| } else { |
| struct __kernel_old_timeval tv = { |
| .tv_sec = tss->ts[0].tv_sec, |
| .tv_usec = tss->ts[0].tv_nsec / 1000, |
| }; |
| put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD, |
| sizeof(tv), &tv); |
| } |
| } |
| } |
| |
| if (sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) |
| has_timestamping = true; |
| else |
| tss->ts[0] = (struct timespec64) {0}; |
| } |
| |
| if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) { |
| if (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) |
| has_timestamping = true; |
| else |
| tss->ts[2] = (struct timespec64) {0}; |
| } |
| |
| if (has_timestamping) { |
| tss->ts[1] = (struct timespec64) {0}; |
| if (sock_flag(sk, SOCK_TSTAMP_NEW)) |
| put_cmsg_scm_timestamping64(msg, tss); |
| else |
| put_cmsg_scm_timestamping(msg, tss); |
| } |
| } |
| |
| static int tcp_inq_hint(struct sock *sk) |
| { |
| const struct tcp_sock *tp = tcp_sk(sk); |
| u32 copied_seq = READ_ONCE(tp->copied_seq); |
| u32 rcv_nxt = READ_ONCE(tp->rcv_nxt); |
| int inq; |
| |
| inq = rcv_nxt - copied_seq; |
| if (unlikely(inq < 0 || copied_seq != READ_ONCE(tp->copied_seq))) { |
| lock_sock(sk); |
| inq = tp->rcv_nxt - tp->copied_seq; |
| release_sock(sk); |
| } |
| /* After receiving a FIN, tell the user-space to continue reading |
| * by returning a non-zero inq. |
| */ |
| if (inq == 0 && sock_flag(sk, SOCK_DONE)) |
| inq = 1; |
| return inq; |
| } |
| |
| /* |
| * 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. |
| */ |
| |
| static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, |
| int flags, struct scm_timestamping_internal *tss, |
| int *cmsg_flags) |
| { |
| 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 sk_buff *skb, *last; |
| u32 urg_hole = 0; |
| |
| err = -ENOTCONN; |
| if (sk->sk_state == TCP_LISTEN) |
| goto out; |
| |
| if (tp->recvmsg_inq) { |
| *cmsg_flags = TCP_CMSG_INQ; |
| msg->msg_get_inq = 1; |
| } |
| timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); |
| |
| /* 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 (unlikely(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. */ |
| |
| last = skb_peek_tail(&sk->sk_receive_queue); |
| skb_queue_walk(&sk->sk_receive_queue, skb) { |
| last = skb; |
| /* Now that we have two receive queues this |
| * shouldn't happen. |
| */ |
| if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), |
| "TCP recvmsg seq # 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 (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
| pr_err_once("%s: found a SYN, please report !\n", __func__); |
| 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), |
| "TCP recvmsg seq # 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 && !READ_ONCE(sk->sk_backlog.tail)) |
| break; |
| |
| if (copied) { |
| if (!timeo || |
| sk->sk_err || |
| sk->sk_state == TCP_CLOSE || |
| (sk->sk_shutdown & RCV_SHUTDOWN) || |
| 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) { |
| /* This occurs when user tries to read |
| * from never connected socket. |
| */ |
| copied = -ENOTCONN; |
| break; |
| } |
| |
| if (!timeo) { |
| copied = -EAGAIN; |
| break; |
| } |
| |
| if (signal_pending(current)) { |
| copied = sock_intr_errno(timeo); |
| break; |
| } |
| } |
| |
| if (copied >= target) { |
| /* Do not sleep, just process backlog. */ |
| __sk_flush_backlog(sk); |
| } else { |
| tcp_cleanup_rbuf(sk, copied); |
| sk_wait_data(sk, &timeo, last); |
| } |
| |
| 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 (unlikely(tp->urg_data)) { |
| u32 urg_offset = tp->urg_seq - *seq; |
| if (urg_offset < used) { |
| if (!urg_offset) { |
| if (!sock_flag(sk, SOCK_URGINLINE)) { |
| WRITE_ONCE(*seq, *seq + 1); |
| 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; |
| } |
| } |
| |
| WRITE_ONCE(*seq, *seq + used); |
| copied += used; |
| len -= used; |
| |
| tcp_rcv_space_adjust(sk); |
| |
| skip_copy: |
| if (unlikely(tp->urg_data) && after(tp->copied_seq, tp->urg_seq)) { |
| WRITE_ONCE(tp->urg_data, 0); |
| tcp_fast_path_check(sk); |
| } |
| |
| if (TCP_SKB_CB(skb)->has_rxtstamp) { |
| tcp_update_recv_tstamps(skb, tss); |
| *cmsg_flags |= TCP_CMSG_TS; |
| } |
| |
| if (used + offset < skb->len) |
| continue; |
| |
| if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) |
| goto found_fin_ok; |
| if (!(flags & MSG_PEEK)) |
| tcp_eat_recv_skb(sk, skb); |
| continue; |
| |
| found_fin_ok: |
| /* Process the FIN. */ |
| WRITE_ONCE(*seq, *seq + 1); |
| if (!(flags & MSG_PEEK)) |
| tcp_eat_recv_skb(sk, skb); |
| break; |
| } while (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); |
| return copied; |
| |
| out: |
| 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; |
| } |
| |
| int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags, |
| int *addr_len) |
| { |
| int cmsg_flags = 0, ret; |
| struct scm_timestamping_internal tss; |
| |
| if (unlikely(flags & MSG_ERRQUEUE)) |
| return inet_recv_error(sk, msg, len, addr_len); |
| |
| if (sk_can_busy_loop(sk) && |
| skb_queue_empty_lockless(&sk->sk_receive_queue) && |
| sk->sk_state == TCP_ESTABLISHED) |
| sk_busy_loop(sk, flags & MSG_DONTWAIT); |
| |
| lock_sock(sk); |
| ret = tcp_recvmsg_locked(sk, msg, len, flags, &tss, &cmsg_flags); |
| release_sock(sk); |
| |
| if ((cmsg_flags || msg->msg_get_inq) && ret >= 0) { |
| if (cmsg_flags & TCP_CMSG_TS) |
| tcp_recv_timestamp(msg, sk, &tss); |
| if (msg->msg_get_inq) { |
| msg->msg_inq = tcp_inq_hint(sk); |
| if (cmsg_flags & TCP_CMSG_INQ) |
| put_cmsg(msg, SOL_TCP, TCP_CM_INQ, |
| sizeof(msg->msg_inq), &msg->msg_inq); |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(tcp_recvmsg); |
| |
| void tcp_set_state(struct sock *sk, int state) |
| { |
| int oldstate = sk->sk_state; |
| |
| /* We defined a new enum for TCP states that are exported in BPF |
| * so as not force the internal TCP states to be frozen. The |
| * following checks will detect if an internal state value ever |
| * differs from the BPF value. If this ever happens, then we will |
| * need to remap the internal value to the BPF value before calling |
| * tcp_call_bpf_2arg. |
| */ |
| BUILD_BUG_ON((int)BPF_TCP_ESTABLISHED != (int)TCP_ESTABLISHED); |
| BUILD_BUG_ON((int)BPF_TCP_SYN_SENT != (int)TCP_SYN_SENT); |
| BUILD_BUG_ON((int)BPF_TCP_SYN_RECV != (int)TCP_SYN_RECV); |
| BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT1 != (int)TCP_FIN_WAIT1); |
| BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT2 != (int)TCP_FIN_WAIT2); |
| BUILD_BUG_ON((int)BPF_TCP_TIME_WAIT != (int)TCP_TIME_WAIT); |
| BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE); |
| BUILD_BUG_ON((int)BPF_TCP_CLOSE_WAIT != (int)TCP_CLOSE_WAIT); |
| BUILD_BUG_ON((int)BPF_TCP_LAST_ACK != (int)TCP_LAST_ACK); |
| BUILD_BUG_ON((int)BPF_TCP_LISTEN != (int)TCP_LISTEN); |
| BUILD_BUG_ON((int)BPF_TCP_CLOSING != (int)TCP_CLOSING); |
| BUILD_BUG_ON((int)BPF_TCP_NEW_SYN_RECV != (int)TCP_NEW_SYN_RECV); |
| BUILD_BUG_ON((int)BPF_TCP_MAX_STATES != (int)TCP_MAX_STATES); |
| |
| /* bpf uapi header bpf.h defines an anonymous enum with values |
| * BPF_TCP_* used by bpf programs. Currently gcc built vmlinux |
| * is able to emit this enum in DWARF due to the above BUILD_BUG_ON. |
| * But clang built vmlinux does not have this enum in DWARF |
| * since clang removes the above code before generating IR/debuginfo. |
| * Let us explicitly emit the type debuginfo to ensure the |
| * above-mentioned anonymous enum in the vmlinux DWARF and hence BTF |
| * regardless of which compiler is used. |
| */ |
| BTF_TYPE_EMIT_ENUM(BPF_TCP_ESTABLISHED); |
| |
| if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_STATE_CB_FLAG)) |
| tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_STATE_CB, oldstate, 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); |
| fallthrough; |
| 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. |
| */ |
| inet_sk_state_store(sk, state); |
| } |
| 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); |
| |
| int tcp_orphan_count_sum(void) |
| { |
| int i, total = 0; |
| |
| for_each_possible_cpu(i) |
| total += per_cpu(tcp_orphan_count, i); |
| |
| return max(total, 0); |
| } |
| |
| static int tcp_orphan_cache; |
| static struct timer_list tcp_orphan_timer; |
| #define TCP_ORPHAN_TIMER_PERIOD msecs_to_jiffies(100) |
| |
| static void tcp_orphan_update(struct timer_list *unused) |
| { |
| WRITE_ONCE(tcp_orphan_cache, tcp_orphan_count_sum()); |
| mod_timer(&tcp_orphan_timer, jiffies + TCP_ORPHAN_TIMER_PERIOD); |
| } |
| |
| static bool tcp_too_many_orphans(int shift) |
| { |
| return READ_ONCE(tcp_orphan_cache) << shift > |
| READ_ONCE(sysctl_tcp_max_orphans); |
| } |
| |
| bool tcp_check_oom(struct sock *sk, int shift) |
| { |
| bool too_many_orphans, out_of_socket_memory; |
| |
| too_many_orphans = tcp_too_many_orphans(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; |
| |
| WRITE_ONCE(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); |
| } |
| |
| /* 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(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(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); |
| |
| local_bh_disable(); |
| bh_lock_sock(sk); |
| /* remove backlog if any, without releasing ownership. */ |
| __release_sock(sk); |
| |
| this_cpu_inc(tcp_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(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) { |
| if (tcp_check_oom(sk, 0)) { |
| tcp_set_state(sk, TCP_CLOSE); |
| tcp_send_active_reset(sk, GFP_ATOMIC); |
| __NET_INC_STATS(sock_net(sk), |
| LINUX_MIB_TCPABORTONMEMORY); |
| } else if (!check_net(sock_net(sk))) { |
| /* Not possible to send reset; just close */ |
| tcp_set_state(sk, TCP_CLOSE); |
| } |
| } |
| |
| if (sk->sk_state == TCP_CLOSE) { |
| struct request_sock *req; |
| |
| req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk, |
| lockdep_sock_is_held(sk)); |
| /* 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(); |
| } |
| |
| void tcp_close(struct sock *sk, long timeout) |
| { |
| lock_sock(sk); |
| __tcp_close(sk, timeout); |
| release_sock(sk); |
| 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); |
| } |
| |
| static void tcp_rtx_queue_purge(struct sock *sk) |
| { |
| struct rb_node *p = rb_first(&sk->tcp_rtx_queue); |
| |
| tcp_sk(sk)->highest_sack = NULL; |
| while (p) { |
| struct sk_buff *skb = rb_to_skb(p); |
| |
| p = rb_next(p); |
| /* Since we are deleting whole queue, no need to |
| * list_del(&skb->tcp_tsorted_anchor) |
| */ |
| tcp_rtx_queue_unlink(skb, sk); |
| tcp_wmem_free_skb(sk, skb); |
| } |
| } |
| |
| void tcp_write_queue_purge(struct sock *sk) |
| { |
| struct sk_buff *skb; |
| |
| tcp_chrono_stop(sk, TCP_CHRONO_BUSY); |
| while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { |
| tcp_skb_tsorted_anchor_cleanup(skb); |
| tcp_wmem_free_skb(sk, skb); |
| } |
| tcp_rtx_queue_purge(sk); |
| INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue); |
| tcp_clear_all_retrans_hints(tcp_sk(sk)); |
| tcp_sk(sk)->packets_out = 0; |
| inet_csk(sk)->icsk_backoff = 0; |
| } |
| |
| 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 old_state = sk->sk_state; |
| u32 seq; |
| |
| /* Deny disconnect if other threads are blocked in sk_wait_event() |
| * or inet_wait_for_connect(). |
| */ |
| if (sk->sk_wait_pending) |
| return -EBUSY; |
| |
| 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); |
| WRITE_ONCE(tp->copied_seq, tp->rcv_nxt); |
| WRITE_ONCE(tp->urg_data, 0); |
| tcp_write_queue_purge(sk); |
| tcp_fastopen_active_disable_ofo_check(sk); |
| skb_rbtree_purge(&tp->out_of_order_queue); |
| |
| inet->inet_dport = 0; |
| |
| inet_bhash2_reset_saddr(sk); |
| |
| WRITE_ONCE(sk->sk_shutdown, 0); |
| sock_reset_flag(sk, SOCK_DONE); |
| tp->srtt_us = 0; |
| tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); |
| tp->rcv_rtt_last_tsecr = 0; |
| |
| seq = tp->write_seq + tp->max_window + 2; |
| if (!seq) |
| seq
|