diff options
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 4864 |
1 files changed, 4864 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c new file mode 100644 index 000000000..90e24c3f6 --- /dev/null +++ b/net/ipv4/tcp.c @@ -0,0 +1,4864 @@ +// 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); + smp_mb__after_atomic(); + } + /* 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; + ret = sk_wait_data(sk, &timeo, NULL); + if (ret < 0) + break; + 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); + +void tcp_splice_eof(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct tcp_sock *tp = tcp_sk(sk); + int mss_now, size_goal; + + if (!tcp_write_queue_tail(sk)) + return; + + lock_sock(sk); + mss_now = tcp_send_mss(sk, &size_goal, 0); + tcp_push(sk, 0, mss_now, tp->nonagle, size_goal); + release_sock(sk); +} +EXPORT_SYMBOL_GPL(tcp_splice_eof); + +/* + * 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 sk_buff *skb; + int copied = 0; + + if (sk->sk_state == TCP_LISTEN) + return -ENOTCONN; + + while ((skb = skb_peek(&sk->sk_receive_queue)) != 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; + } + copied += used; + + if (tcp_flags & TCPHDR_FIN) + 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 (READ_ONCE(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 (READ_ONCE(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); + err = sk_wait_data(sk, &timeo, last); + if (err < 0) { + err = copied ? : err; + goto out; + } + } + + 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; + + 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 = 1; + WRITE_ONCE(tp->write_seq, seq); + + icsk->icsk_backoff = 0; + icsk->icsk_probes_out = 0; + icsk->icsk_probes_tstamp = 0; + icsk->icsk_rto = TCP_TIMEOUT_INIT; + icsk->icsk_rto_min = TCP_RTO_MIN; + icsk->icsk_delack_max = TCP_DELACK_MAX; + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; + tcp_snd_cwnd_set(tp, TCP_INIT_CWND); + tp->snd_cwnd_cnt = 0; + tp->is_cwnd_limited = 0; + tp->max_packets_out = 0; + tp->window_clamp = 0; + tp->delivered = 0; + tp->delivered_ce = 0; + if (icsk->icsk_ca_ops->release) + icsk->icsk_ca_ops->release(sk); + memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv)); + icsk->icsk_ca_initialized = 0; + tcp_set_ca_state(sk, TCP_CA_Open); + tp->is_sack_reneg = 0; + tcp_clear_retrans(tp); + tp->total_retrans = 0; + inet_csk_delack_init(sk); + /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0 + * issue in __tcp_select_window() + */ + icsk->icsk_ack.rcv_mss = TCP_MIN_MSS; + memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); + __sk_dst_reset(sk); + dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL)); + tcp_saved_syn_free(tp); + tp->compressed_ack = 0; + tp->segs_in = 0; + tp->segs_out = 0; + tp->bytes_sent = 0; + tp->bytes_acked = 0; + tp->bytes_received = 0; + tp->bytes_retrans = 0; + tp->data_segs_in = 0; + tp->data_segs_out = 0; + tp->duplicate_sack[0].start_seq = 0; + tp->duplicate_sack[0].end_seq = 0; + tp->dsack_dups = 0; + tp->reord_seen = 0; + tp->retrans_out = 0; + tp->sacked_out = 0; + tp->tlp_high_seq = 0; + tp->last_oow_ack_time = 0; + /* There's a bubble in the pipe until at least the first ACK. */ + tp->app_limited = ~0U; + tp->rate_app_limited = 1; + tp->rack.mstamp = 0; + tp->rack.advanced = 0; + tp->rack.reo_wnd_steps = 1; + tp->rack.last_delivered = 0; + tp->rack.reo_wnd_persist = 0; + tp->rack.dsack_seen = 0; + tp->syn_data_acked = 0; + tp->rx_opt.saw_tstamp = 0; + tp->rx_opt.dsack = 0; + tp->rx_opt.num_sacks = 0; + tp->rcv_ooopack = 0; + + + /* Clean up fastopen related fields */ + tcp_free_fastopen_req(tp); + inet->defer_connect = 0; + tp->fastopen_client_fail = 0; + + WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); + + if (sk->sk_frag.page) { + put_page(sk->sk_frag.page); + sk->sk_frag.page = NULL; + sk->sk_frag.offset = 0; + } + sk_error_report(sk); + return 0; +} +EXPORT_SYMBOL(tcp_disconnect); + +static inline bool tcp_can_repair_sock(const struct sock *sk) +{ + return sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) && + (sk->sk_state != TCP_LISTEN); +} + +static int tcp_repair_set_window(struct tcp_sock *tp, sockptr_t optbuf, int len) +{ + struct tcp_repair_window opt; + + if (!tp->repair) + return -EPERM; + + if (len != sizeof(opt)) + return -EINVAL; + + if (copy_from_sockptr(&opt, optbuf, sizeof(opt))) + return -EFAULT; + + if (opt.max_window < opt.snd_wnd) + return -EINVAL; + + if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd)) + return -EINVAL; + + if (after(opt.rcv_wup, tp->rcv_nxt)) + return -EINVAL; + + tp->snd_wl1 = opt.snd_wl1; + tp->snd_wnd = opt.snd_wnd; + tp->max_window = opt.max_window; + + tp->rcv_wnd = opt.rcv_wnd; + tp->rcv_wup = opt.rcv_wup; + + return 0; +} + +static int tcp_repair_options_est(struct sock *sk, sockptr_t optbuf, + unsigned int len) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_repair_opt opt; + size_t offset = 0; + + while (len >= sizeof(opt)) { + if (copy_from_sockptr_offset(&opt, optbuf, offset, sizeof(opt))) + return -EFAULT; + + offset += sizeof(opt); + len -= sizeof(opt); + + switch (opt.opt_code) { + case TCPOPT_MSS: + tp->rx_opt.mss_clamp = opt.opt_val; + tcp_mtup_init(sk); + break; + case TCPOPT_WINDOW: + { + u16 snd_wscale = opt.opt_val & 0xFFFF; + u16 rcv_wscale = opt.opt_val >> 16; + + if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE) + 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; + break; + case TCPOPT_TIMESTAMP: + if (opt.opt_val != 0) + return -EINVAL; + + tp->rx_opt.tstamp_ok = 1; + break; + } + } + + return 0; +} + +DEFINE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); +EXPORT_SYMBOL(tcp_tx_delay_enabled); + +static void tcp_enable_tx_delay(void) +{ + if (!static_branch_unlikely(&tcp_tx_delay_enabled)) { + static int __tcp_tx_delay_enabled = 0; + + if (cmpxchg(&__tcp_tx_delay_enabled, 0, 1) == 0) { + static_branch_enable(&tcp_tx_delay_enabled); + pr_info("TCP_TX_DELAY enabled\n"); + } + } +} + +/* 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. + */ +void __tcp_sock_set_cork(struct sock *sk, bool on) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (on) { + 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); + } +} + +void tcp_sock_set_cork(struct sock *sk, bool on) +{ + lock_sock(sk); + __tcp_sock_set_cork(sk, on); + release_sock(sk); +} +EXPORT_SYMBOL(tcp_sock_set_cork); + +/* 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. + */ +void __tcp_sock_set_nodelay(struct sock *sk, bool on) +{ + if (on) { + tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; + tcp_push_pending_frames(sk); + } else { + tcp_sk(sk)->nonagle &= ~TCP_NAGLE_OFF; + } +} + +void tcp_sock_set_nodelay(struct sock *sk) +{ + lock_sock(sk); + __tcp_sock_set_nodelay(sk, true); + release_sock(sk); +} +EXPORT_SYMBOL(tcp_sock_set_nodelay); + +static void __tcp_sock_set_quickack(struct sock *sk, int val) +{ + if (!val) { + inet_csk_enter_pingpong_mode(sk); + return; + } + + inet_csk_exit_pingpong_mode(sk); + if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && + inet_csk_ack_scheduled(sk)) { + inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_PUSHED; + tcp_cleanup_rbuf(sk, 1); + if (!(val & 1)) + inet_csk_enter_pingpong_mode(sk); + } +} + +void tcp_sock_set_quickack(struct sock *sk, int val) +{ + lock_sock(sk); + __tcp_sock_set_quickack(sk, val); + release_sock(sk); +} +EXPORT_SYMBOL(tcp_sock_set_quickack); + +int tcp_sock_set_syncnt(struct sock *sk, int val) +{ + if (val < 1 || val > MAX_TCP_SYNCNT) + return -EINVAL; + + lock_sock(sk); + WRITE_ONCE(inet_csk(sk)->icsk_syn_retries, val); + release_sock(sk); + return 0; +} +EXPORT_SYMBOL(tcp_sock_set_syncnt); + +void tcp_sock_set_user_timeout(struct sock *sk, u32 val) +{ + lock_sock(sk); + WRITE_ONCE(inet_csk(sk)->icsk_user_timeout, val); + release_sock(sk); +} +EXPORT_SYMBOL(tcp_sock_set_user_timeout); + +int tcp_sock_set_keepidle_locked(struct sock *sk, int val) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (val < 1 || val > MAX_TCP_KEEPIDLE) + return -EINVAL; + + /* Paired with WRITE_ONCE() in keepalive_time_when() */ + WRITE_ONCE(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); + } + + return 0; +} + +int tcp_sock_set_keepidle(struct sock *sk, int val) +{ + int err; + + lock_sock(sk); + err = tcp_sock_set_keepidle_locked(sk, val); + release_sock(sk); + return err; +} +EXPORT_SYMBOL(tcp_sock_set_keepidle); + +int tcp_sock_set_keepintvl(struct sock *sk, int val) +{ + if (val < 1 || val > MAX_TCP_KEEPINTVL) + return -EINVAL; + + lock_sock(sk); + WRITE_ONCE(tcp_sk(sk)->keepalive_intvl, val * HZ); + release_sock(sk); + return 0; +} +EXPORT_SYMBOL(tcp_sock_set_keepintvl); + +int tcp_sock_set_keepcnt(struct sock *sk, int val) +{ + if (val < 1 || val > MAX_TCP_KEEPCNT) + return -EINVAL; + + lock_sock(sk); + /* Paired with READ_ONCE() in keepalive_probes() */ + WRITE_ONCE(tcp_sk(sk)->keepalive_probes, val); + release_sock(sk); + return 0; +} +EXPORT_SYMBOL(tcp_sock_set_keepcnt); + +int tcp_set_window_clamp(struct sock *sk, int val) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (!val) { + if (sk->sk_state != TCP_CLOSE) + return -EINVAL; + tp->window_clamp = 0; + } else { + u32 new_rcv_ssthresh, old_window_clamp = tp->window_clamp; + u32 new_window_clamp = val < SOCK_MIN_RCVBUF / 2 ? + SOCK_MIN_RCVBUF / 2 : val; + + if (new_window_clamp == old_window_clamp) + return 0; + + tp->window_clamp = new_window_clamp; + if (new_window_clamp < old_window_clamp) { + /* need to apply the reserved mem provisioning only + * when shrinking the window clamp + */ + __tcp_adjust_rcv_ssthresh(sk, tp->window_clamp); + + } else { + new_rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp); + tp->rcv_ssthresh = max(new_rcv_ssthresh, + tp->rcv_ssthresh); + } + } + return 0; +} + +/* + * Socket option code for TCP. + */ +int do_tcp_setsockopt(struct sock *sk, int level, int optname, + sockptr_t optval, unsigned int optlen) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct inet_connection_sock *icsk = inet_csk(sk); + struct net *net = sock_net(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_sockptr(name, optval, + min_t(long, TCP_CA_NAME_MAX-1, optlen)); + if (val < 0) + return -EFAULT; + name[val] = 0; + + sockopt_lock_sock(sk); + err = tcp_set_congestion_control(sk, name, !has_current_bpf_ctx(), + sockopt_ns_capable(sock_net(sk)->user_ns, + CAP_NET_ADMIN)); + sockopt_release_sock(sk); + return err; + } + case TCP_ULP: { + char name[TCP_ULP_NAME_MAX]; + + if (optlen < 1) + return -EINVAL; + + val = strncpy_from_sockptr(name, optval, + min_t(long, TCP_ULP_NAME_MAX - 1, + optlen)); + if (val < 0) + return -EFAULT; + name[val] = 0; + + sockopt_lock_sock(sk); + err = tcp_set_ulp(sk, name); + sockopt_release_sock(sk); + return err; + } + case TCP_FASTOPEN_KEY: { + __u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH]; + __u8 *backup_key = NULL; + + /* Allow a backup key as well to facilitate key rotation + * First key is the active one. + */ + if (optlen != TCP_FASTOPEN_KEY_LENGTH && + optlen != TCP_FASTOPEN_KEY_BUF_LENGTH) + return -EINVAL; + + if (copy_from_sockptr(key, optval, optlen)) + return -EFAULT; + + if (optlen == TCP_FASTOPEN_KEY_BUF_LENGTH) + backup_key = key + TCP_FASTOPEN_KEY_LENGTH; + + return tcp_fastopen_reset_cipher(net, sk, key, backup_key); + } + default: + /* fallthru */ + break; + } + + if (optlen < sizeof(int)) + return -EINVAL; + + if (copy_from_sockptr(&val, optval, sizeof(val))) + return -EFAULT; + + sockopt_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 && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) { + err = -EINVAL; + break; + } + tp->rx_opt.user_mss = val; + break; + + case TCP_NODELAY: + __tcp_sock_set_nodelay(sk, val); + 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; + break; + + case TCP_REPAIR: + if (!tcp_can_repair_sock(sk)) + err = -EPERM; + else if (val == TCP_REPAIR_ON) { + tp->repair = 1; + sk->sk_reuse = SK_FORCE_REUSE; + tp->repair_queue = TCP_NO_QUEUE; + } else if (val == TCP_REPAIR_OFF) { + tp->repair = 0; + sk->sk_reuse = SK_NO_REUSE; + tcp_send_window_probe(sk); + } else if (val == TCP_REPAIR_OFF_NO_WP) { + tp->repair = 0; + sk->sk_reuse = SK_NO_REUSE; + } else + err = -EINVAL; + + break; + + case TCP_REPAIR_QUEUE: + if (!tp->repair) + err = -EPERM; + else if ((unsigned int)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) { + if (!tcp_rtx_queue_empty(sk)) + err = -EPERM; + else + WRITE_ONCE(tp->write_seq, val); + } else if (tp->repair_queue == TCP_RECV_QUEUE) { + if (tp->rcv_nxt != tp->copied_seq) { + err = -EPERM; + } else { + WRITE_ONCE(tp->rcv_nxt, val); + WRITE_ONCE(tp->copied_seq, val); + } + } else { + err = -EINVAL; + } + break; + + case TCP_REPAIR_OPTIONS: + if (!tp->repair) + err = -EINVAL; + else if (sk->sk_state == TCP_ESTABLISHED && !tp->bytes_sent) + err = tcp_repair_options_est(sk, optval, optlen); + else + err = -EPERM; + break; + + case TCP_CORK: + __tcp_sock_set_cork(sk, val); + break; + + case TCP_KEEPIDLE: + err = tcp_sock_set_keepidle_locked(sk, val); + break; + case TCP_KEEPINTVL: + if (val < 1 || val > MAX_TCP_KEEPINTVL) + err = -EINVAL; + else + WRITE_ONCE(tp->keepalive_intvl, val * HZ); + break; + case TCP_KEEPCNT: + if (val < 1 || val > MAX_TCP_KEEPCNT) + err = -EINVAL; + else + WRITE_ONCE(tp->keepalive_probes, val); + break; + case TCP_SYNCNT: + if (val < 1 || val > MAX_TCP_SYNCNT) + err = -EINVAL; + else + WRITE_ONCE(icsk->icsk_syn_retries, val); + break; + + case TCP_SAVE_SYN: + /* 0: disable, 1: enable, 2: start from ether_header */ + if (val < 0 || val > 2) + err = -EINVAL; + else + tp->save_syn = val; + break; + + case TCP_LINGER2: + if (val < 0) + WRITE_ONCE(tp->linger2, -1); + else if (val > TCP_FIN_TIMEOUT_MAX / HZ) + WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX); + else + WRITE_ONCE(tp->linger2, val * HZ); + break; + + case TCP_DEFER_ACCEPT: + /* Translate value in seconds to number of retransmits */ + WRITE_ONCE(icsk->icsk_accept_queue.rskq_defer_accept, + secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, + TCP_RTO_MAX / HZ)); + break; + + case TCP_WINDOW_CLAMP: + err = tcp_set_window_clamp(sk, val); + break; + + case TCP_QUICKACK: + __tcp_sock_set_quickack(sk, val); + break; + +#ifdef CONFIG_TCP_MD5SIG + case TCP_MD5SIG: + case TCP_MD5SIG_EXT: + err = tp->af_specific->md5_parse(sk, optname, 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 + WRITE_ONCE(icsk->icsk_user_timeout, val); + break; + + case TCP_FASTOPEN: + if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE | + TCPF_LISTEN))) { + tcp_fastopen_init_key_once(net); + + fastopen_queue_tune(sk, val); + } else { + err = -EINVAL; + } + break; + case TCP_FASTOPEN_CONNECT: + if (val > 1 || val < 0) { + err = -EINVAL; + } else if (READ_ONCE(net->ipv4.sysctl_tcp_fastopen) & + TFO_CLIENT_ENABLE) { + if (sk->sk_state == TCP_CLOSE) + tp->fastopen_connect = val; + else + err = -EINVAL; + } else { + err = -EOPNOTSUPP; + } + break; + case TCP_FASTOPEN_NO_COOKIE: + if (val > 1 || val < 0) + err = -EINVAL; + else if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) + err = -EINVAL; + else + tp->fastopen_no_cookie = val; + break; + case TCP_TIMESTAMP: + if (!tp->repair) + err = -EPERM; + else + WRITE_ONCE(tp->tsoffset, val - tcp_time_stamp_raw()); + break; + case TCP_REPAIR_WINDOW: + err = tcp_repair_set_window(tp, optval, optlen); + break; + case TCP_NOTSENT_LOWAT: + WRITE_ONCE(tp->notsent_lowat, val); + sk->sk_write_space(sk); + break; + case TCP_INQ: + if (val > 1 || val < 0) + err = -EINVAL; + else + tp->recvmsg_inq = val; + break; + case TCP_TX_DELAY: + if (val) + tcp_enable_tx_delay(); + WRITE_ONCE(tp->tcp_tx_delay, val); + break; + default: + err = -ENOPROTOOPT; + break; + } + + sockopt_release_sock(sk); + return err; +} + +int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, + unsigned int optlen) +{ + const struct inet_connection_sock *icsk = inet_csk(sk); + + if (level != SOL_TCP) + /* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */ + return READ_ONCE(icsk->icsk_af_ops)->setsockopt(sk, level, optname, + optval, optlen); + return do_tcp_setsockopt(sk, level, optname, optval, optlen); +} +EXPORT_SYMBOL(tcp_setsockopt); + +static void tcp_get_info_chrono_stats(const struct tcp_sock *tp, + struct tcp_info *info) +{ + u64 stats[__TCP_CHRONO_MAX], total = 0; + enum tcp_chrono i; + + for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) { + stats[i] = tp->chrono_stat[i - 1]; + if (i == tp->chrono_type) + stats[i] += tcp_jiffies32 - tp->chrono_start; + stats[i] *= USEC_PER_SEC / HZ; + total += stats[i]; + } + + info->tcpi_busy_time = total; + info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED]; + info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED]; +} + +/* 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); /* iff sk_type == SOCK_STREAM */ + const struct inet_connection_sock *icsk = inet_csk(sk); + unsigned long rate; + u32 now; + u64 rate64; + bool slow; + + memset(info, 0, sizeof(*info)); + if (sk->sk_type != SOCK_STREAM) + return; + + info->tcpi_state = inet_sk_state_load(sk); + + /* Report meaningful fields for all TCP states, including listeners */ + rate = READ_ONCE(sk->sk_pacing_rate); + rate64 = (rate != ~0UL) ? rate : ~0ULL; + info->tcpi_pacing_rate = rate64; + + rate = READ_ONCE(sk->sk_max_pacing_rate); + rate64 = (rate != ~0UL) ? rate : ~0ULL; + info->tcpi_max_pacing_rate = rate64; + + info->tcpi_reordering = tp->reordering; + info->tcpi_snd_cwnd = tcp_snd_cwnd(tp); + + if (info->tcpi_state == TCP_LISTEN) { + /* listeners aliased fields : + * tcpi_unacked -> Number of children ready for accept() + * tcpi_sacked -> max backlog + */ + info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog); + info->tcpi_sacked = READ_ONCE(sk->sk_max_ack_backlog); + return; + } + + slow = lock_sock_fast(sk); + + 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; + + info->tcpi_unacked = tp->packets_out; + info->tcpi_sacked = tp->sacked_out; + + info->tcpi_lost = tp->lost_out; + info->tcpi_retrans = tp->retrans_out; + + now = tcp_jiffies32; + 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_advmss = tp->advmss; + + info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3; + info->tcpi_rcv_space = tp->rcvq_space.space; + + info->tcpi_total_retrans = tp->total_retrans; + + info->tcpi_bytes_acked = tp->bytes_acked; + info->tcpi_bytes_received = tp->bytes_received; + info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt); + tcp_get_info_chrono_stats(tp, info); + + info->tcpi_segs_out = tp->segs_out; + + /* segs_in and data_segs_in can be updated from tcp_segs_in() from BH */ + info->tcpi_segs_in = READ_ONCE(tp->segs_in); + info->tcpi_data_segs_in = READ_ONCE(tp->data_segs_in); + + info->tcpi_min_rtt = tcp_min_rtt(tp); + info->tcpi_data_segs_out = tp->data_segs_out; + + info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0; + rate64 = tcp_compute_delivery_rate(tp); + if (rate64) + info->tcpi_delivery_rate = rate64; + info->tcpi_delivered = tp->delivered; + info->tcpi_delivered_ce = tp->delivered_ce; + info->tcpi_bytes_sent = tp->bytes_sent; + info->tcpi_bytes_retrans = tp->bytes_retrans; + info->tcpi_dsack_dups = tp->dsack_dups; + info->tcpi_reord_seen = tp->reord_seen; + info->tcpi_rcv_ooopack = tp->rcv_ooopack; + info->tcpi_snd_wnd = tp->snd_wnd; + info->tcpi_fastopen_client_fail = tp->fastopen_client_fail; + unlock_sock_fast(sk, slow); +} +EXPORT_SYMBOL_GPL(tcp_get_info); + +static size_t tcp_opt_stats_get_size(void) +{ + return + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BUSY */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_PACING_RATE */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_CWND */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_REORDERING */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_MIN_RTT */ + nla_total_size(sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */ + nla_total_size(sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */ + nla_total_size(sizeof(u8)) + /* TCP_NLA_CA_STATE */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */ + nla_total_size(sizeof(u16)) + /* TCP_NLA_TIMEOUT_REHASH */ + nla_total_size(sizeof(u32)) + /* TCP_NLA_BYTES_NOTSENT */ + nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_EDT */ + nla_total_size(sizeof(u8)) + /* TCP_NLA_TTL */ + 0; +} + +/* Returns TTL or hop limit of an incoming packet from skb. */ +static u8 tcp_skb_ttl_or_hop_limit(const struct sk_buff *skb) +{ + if (skb->protocol == htons(ETH_P_IP)) + return ip_hdr(skb)->ttl; + else if (skb->protocol == htons(ETH_P_IPV6)) + return ipv6_hdr(skb)->hop_limit; + else + return 0; +} + +struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, + const struct sk_buff *orig_skb, + const struct sk_buff *ack_skb) +{ + const struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *stats; + struct tcp_info info; + unsigned long rate; + u64 rate64; + + stats = alloc_skb(tcp_opt_stats_get_size(), GFP_ATOMIC); + if (!stats) + return NULL; + + tcp_get_info_chrono_stats(tp, &info); + nla_put_u64_64bit(stats, TCP_NLA_BUSY, + info.tcpi_busy_time, TCP_NLA_PAD); + nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED, + info.tcpi_rwnd_limited, TCP_NLA_PAD); + nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED, + info.tcpi_sndbuf_limited, TCP_NLA_PAD); + nla_put_u64_64bit(stats, TCP_NLA_DATA_SEGS_OUT, + tp->data_segs_out, TCP_NLA_PAD); + nla_put_u64_64bit(stats, TCP_NLA_TOTAL_RETRANS, + tp->total_retrans, TCP_NLA_PAD); + + rate = READ_ONCE(sk->sk_pacing_rate); + rate64 = (rate != ~0UL) ? rate : ~0ULL; + nla_put_u64_64bit(stats, TCP_NLA_PACING_RATE, rate64, TCP_NLA_PAD); + + rate64 = tcp_compute_delivery_rate(tp); + nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD); + + nla_put_u32(stats, TCP_NLA_SND_CWND, tcp_snd_cwnd(tp)); + nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering); + nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp)); + + nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits); + nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited); + nla_put_u32(stats, TCP_NLA_SND_SSTHRESH, tp->snd_ssthresh); + nla_put_u32(stats, TCP_NLA_DELIVERED, tp->delivered); + nla_put_u32(stats, TCP_NLA_DELIVERED_CE, tp->delivered_ce); + + nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, tp->write_seq - tp->snd_una); + nla_put_u8(stats, TCP_NLA_CA_STATE, inet_csk(sk)->icsk_ca_state); + + nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent, + TCP_NLA_PAD); + nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans, + TCP_NLA_PAD); + nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups); + nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen); + nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3); + nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, tp->timeout_rehash); + nla_put_u32(stats, TCP_NLA_BYTES_NOTSENT, + max_t(int, 0, tp->write_seq - tp->snd_nxt)); + nla_put_u64_64bit(stats, TCP_NLA_EDT, orig_skb->skb_mstamp_ns, + TCP_NLA_PAD); + if (ack_skb) + nla_put_u8(stats, TCP_NLA_TTL, + tcp_skb_ttl_or_hop_limit(ack_skb)); + + return stats; +} + +int do_tcp_getsockopt(struct sock *sk, int level, + int optname, sockptr_t optval, sockptr_t optlen) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + struct tcp_sock *tp = tcp_sk(sk); + struct net *net = sock_net(sk); + int val, len; + + if (copy_from_sockptr(&len, optlen, sizeof(int))) + 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 (tp->rx_opt.user_mss && + ((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 = READ_ONCE(icsk->icsk_syn_retries) ? : + READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); + break; + case TCP_LINGER2: + val = READ_ONCE(tp->linger2); + if (val >= 0) + val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ; + break; + case TCP_DEFER_ACCEPT: + val = READ_ONCE(icsk->icsk_accept_queue.rskq_defer_accept); + val = retrans_to_secs(val, 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 (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + + tcp_get_info(sk, &info); + + len = min_t(unsigned int, len, sizeof(info)); + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(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 (copy_from_sockptr(&len, optlen, sizeof(int))) + 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 (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(optval, &info, len)) + return -EFAULT; + return 0; + } + case TCP_QUICKACK: + val = !inet_csk_in_pingpong_mode(sk); + break; + + case TCP_CONGESTION: + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + len = min_t(unsigned int, len, TCP_CA_NAME_MAX); + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(optval, icsk->icsk_ca_ops->name, len)) + return -EFAULT; + return 0; + + case TCP_ULP: + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + len = min_t(unsigned int, len, TCP_ULP_NAME_MAX); + if (!icsk->icsk_ulp_ops) { + len = 0; + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + return 0; + } + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(optval, icsk->icsk_ulp_ops->name, len)) + return -EFAULT; + return 0; + + case TCP_FASTOPEN_KEY: { + u64 key[TCP_FASTOPEN_KEY_BUF_LENGTH / sizeof(u64)]; + unsigned int key_len; + + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + + key_len = tcp_fastopen_get_cipher(net, icsk, key) * + TCP_FASTOPEN_KEY_LENGTH; + len = min_t(unsigned int, len, key_len); + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(optval, key, len)) + return -EFAULT; + return 0; + } + case TCP_THIN_LINEAR_TIMEOUTS: + val = tp->thin_lto; + break; + + case TCP_THIN_DUPACK: + val = 0; + 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_REPAIR_WINDOW: { + struct tcp_repair_window opt; + + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + + if (len != sizeof(opt)) + return -EINVAL; + + if (!tp->repair) + return -EPERM; + + opt.snd_wl1 = tp->snd_wl1; + opt.snd_wnd = tp->snd_wnd; + opt.max_window = tp->max_window; + opt.rcv_wnd = tp->rcv_wnd; + opt.rcv_wup = tp->rcv_wup; + + if (copy_to_sockptr(optval, &opt, len)) + return -EFAULT; + return 0; + } + 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 = READ_ONCE(icsk->icsk_user_timeout); + break; + + case TCP_FASTOPEN: + val = READ_ONCE(icsk->icsk_accept_queue.fastopenq.max_qlen); + break; + + case TCP_FASTOPEN_CONNECT: + val = tp->fastopen_connect; + break; + + case TCP_FASTOPEN_NO_COOKIE: + val = tp->fastopen_no_cookie; + break; + + case TCP_TX_DELAY: + val = READ_ONCE(tp->tcp_tx_delay); + break; + + case TCP_TIMESTAMP: + val = tcp_time_stamp_raw() + READ_ONCE(tp->tsoffset); + break; + case TCP_NOTSENT_LOWAT: + val = READ_ONCE(tp->notsent_lowat); + break; + case TCP_INQ: + val = tp->recvmsg_inq; + break; + case TCP_SAVE_SYN: + val = tp->save_syn; + break; + case TCP_SAVED_SYN: { + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + + sockopt_lock_sock(sk); + if (tp->saved_syn) { + if (len < tcp_saved_syn_len(tp->saved_syn)) { + len = tcp_saved_syn_len(tp->saved_syn); + if (copy_to_sockptr(optlen, &len, sizeof(int))) { + sockopt_release_sock(sk); + return -EFAULT; + } + sockopt_release_sock(sk); + return -EINVAL; + } + len = tcp_saved_syn_len(tp->saved_syn); + if (copy_to_sockptr(optlen, &len, sizeof(int))) { + sockopt_release_sock(sk); + return -EFAULT; + } + if (copy_to_sockptr(optval, tp->saved_syn->data, len)) { + sockopt_release_sock(sk); + return -EFAULT; + } + tcp_saved_syn_free(tp); + sockopt_release_sock(sk); + } else { + sockopt_release_sock(sk); + len = 0; + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + } + return 0; + } +#ifdef CONFIG_MMU + case TCP_ZEROCOPY_RECEIVE: { + struct scm_timestamping_internal tss; + struct tcp_zerocopy_receive zc = {}; + int err; + + if (copy_from_sockptr(&len, optlen, sizeof(int))) + return -EFAULT; + if (len < 0 || + len < offsetofend(struct tcp_zerocopy_receive, length)) + return -EINVAL; + if (unlikely(len > sizeof(zc))) { + err = check_zeroed_sockptr(optval, sizeof(zc), + len - sizeof(zc)); + if (err < 1) + return err == 0 ? -EINVAL : err; + len = sizeof(zc); + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + } + if (copy_from_sockptr(&zc, optval, len)) + return -EFAULT; + if (zc.reserved) + return -EINVAL; + if (zc.msg_flags & ~(TCP_VALID_ZC_MSG_FLAGS)) + return -EINVAL; + sockopt_lock_sock(sk); + err = tcp_zerocopy_receive(sk, &zc, &tss); + err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname, + &zc, &len, err); + sockopt_release_sock(sk); + if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags)) + goto zerocopy_rcv_cmsg; + switch (len) { + case offsetofend(struct tcp_zerocopy_receive, msg_flags): + goto zerocopy_rcv_cmsg; + case offsetofend(struct tcp_zerocopy_receive, msg_controllen): + case offsetofend(struct tcp_zerocopy_receive, msg_control): + case offsetofend(struct tcp_zerocopy_receive, flags): + case offsetofend(struct tcp_zerocopy_receive, copybuf_len): + case offsetofend(struct tcp_zerocopy_receive, copybuf_address): + case offsetofend(struct tcp_zerocopy_receive, err): + goto zerocopy_rcv_sk_err; + case offsetofend(struct tcp_zerocopy_receive, inq): + goto zerocopy_rcv_inq; + case offsetofend(struct tcp_zerocopy_receive, length): + default: + goto zerocopy_rcv_out; + } +zerocopy_rcv_cmsg: + if (zc.msg_flags & TCP_CMSG_TS) + tcp_zc_finalize_rx_tstamp(sk, &zc, &tss); + else + zc.msg_flags = 0; +zerocopy_rcv_sk_err: + if (!err) + zc.err = sock_error(sk); +zerocopy_rcv_inq: + zc.inq = tcp_inq_hint(sk); +zerocopy_rcv_out: + if (!err && copy_to_sockptr(optval, &zc, len)) + err = -EFAULT; + return err; + } +#endif + default: + return -ENOPROTOOPT; + } + + if (copy_to_sockptr(optlen, &len, sizeof(int))) + return -EFAULT; + if (copy_to_sockptr(optval, &val, len)) + return -EFAULT; + return 0; +} + +bool tcp_bpf_bypass_getsockopt(int level, int optname) +{ + /* TCP do_tcp_getsockopt has optimized getsockopt implementation + * to avoid extra socket lock for TCP_ZEROCOPY_RECEIVE. + */ + if (level == SOL_TCP && optname == TCP_ZEROCOPY_RECEIVE) + return true; + + return false; +} +EXPORT_SYMBOL(tcp_bpf_bypass_getsockopt); + +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) + /* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */ + return READ_ONCE(icsk->icsk_af_ops)->getsockopt(sk, level, optname, + optval, optlen); + return do_tcp_getsockopt(sk, level, optname, USER_SOCKPTR(optval), + USER_SOCKPTR(optlen)); +} +EXPORT_SYMBOL(tcp_getsockopt); + +#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) +{ + struct crypto_ahash *hash; + int cpu; + + hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hash)) + return; + + for_each_possible_cpu(cpu) { + void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch; + struct ahash_request *req; + + if (!scratch) { + scratch = kmalloc_node(sizeof(union tcp_md5sum_block) + + sizeof(struct tcphdr), + GFP_KERNEL, + cpu_to_node(cpu)); + if (!scratch) + return; + per_cpu(tcp_md5sig_pool, cpu).scratch = scratch; + } + if (per_cpu(tcp_md5sig_pool, cpu).md5_req) + continue; + + req = ahash_request_alloc(hash, GFP_KERNEL); + if (!req) + return; + + ahash_request_set_callback(req, 0, NULL, NULL); + + per_cpu(tcp_md5sig_pool, cpu).md5_req = req; + } + /* before setting tcp_md5sig_pool_populated, we must commit all writes + * to memory. See smp_rmb() in tcp_get_md5sig_pool() + */ + smp_wmb(); + /* Paired with READ_ONCE() from tcp_alloc_md5sig_pool() + * and tcp_get_md5sig_pool(). + */ + WRITE_ONCE(tcp_md5sig_pool_populated, true); +} + +bool tcp_alloc_md5sig_pool(void) +{ + /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ + if (unlikely(!READ_ONCE(tcp_md5sig_pool_populated))) { + mutex_lock(&tcp_md5sig_mutex); + + if (!tcp_md5sig_pool_populated) { + __tcp_alloc_md5sig_pool(); + if (tcp_md5sig_pool_populated) + static_branch_inc(&tcp_md5_needed); + } + + mutex_unlock(&tcp_md5sig_mutex); + } + /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ + return READ_ONCE(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(); + + /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ + if (READ_ONCE(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_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 ahash_request *req = hp->md5_req; + 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); + ahash_request_set_crypt(req, &sg, NULL, head_data_len); + if (crypto_ahash_update(req)) + return 1; + + for (i = 0; i < shi->nr_frags; ++i) { + const skb_frag_t *f = &shi->frags[i]; + unsigned int offset = skb_frag_off(f); + struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); + + sg_set_page(&sg, page, skb_frag_size(f), + offset_in_page(offset)); + ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f)); + if (crypto_ahash_update(req)) + 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) +{ + u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */ + struct scatterlist sg; + + sg_init_one(&sg, key->key, keylen); + ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen); + + /* We use data_race() because tcp_md5_do_add() might change key->key under us */ + return data_race(crypto_ahash_update(hp->md5_req)); +} +EXPORT_SYMBOL(tcp_md5_hash_key); + +/* Called with rcu_read_lock() */ +enum skb_drop_reason +tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, + const void *saddr, const void *daddr, + int family, int dif, int sdif) +{ + /* + * This gets called for each TCP segment that arrives + * so we want to be efficient. + * We have 3 drop cases: + * o No MD5 hash and one expected. + * o MD5 hash and we're not expecting one. + * o MD5 hash and its wrong. + */ + const __u8 *hash_location = NULL; + struct tcp_md5sig_key *hash_expected; + const struct tcphdr *th = tcp_hdr(skb); + struct tcp_sock *tp = tcp_sk(sk); + int genhash, l3index; + u8 newhash[16]; + + /* sdif set, means packet ingressed via a device + * in an L3 domain and dif is set to the l3mdev + */ + l3index = sdif ? dif : 0; + + hash_expected = tcp_md5_do_lookup(sk, l3index, saddr, family); + hash_location = tcp_parse_md5sig_option(th); + + /* We've parsed the options - do we have a hash? */ + if (!hash_expected && !hash_location) + return SKB_NOT_DROPPED_YET; + + if (hash_expected && !hash_location) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); + return SKB_DROP_REASON_TCP_MD5NOTFOUND; + } + + if (!hash_expected && hash_location) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); + return SKB_DROP_REASON_TCP_MD5UNEXPECTED; + } + + /* Check the signature. + * To support dual stack listeners, we need to handle + * IPv4-mapped case. + */ + if (family == AF_INET) + genhash = tcp_v4_md5_hash_skb(newhash, + hash_expected, + NULL, skb); + else + genhash = tp->af_specific->calc_md5_hash(newhash, + hash_expected, + NULL, skb); + + if (genhash || memcmp(hash_location, newhash, 16) != 0) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); + if (family == AF_INET) { + net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n", + saddr, ntohs(th->source), + daddr, ntohs(th->dest), + genhash ? " tcp_v4_calc_md5_hash failed" + : "", l3index); + } else { + net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u L3 index %d\n", + genhash ? "failed" : "mismatch", + saddr, ntohs(th->source), + daddr, ntohs(th->dest), l3index); + } + return SKB_DROP_REASON_TCP_MD5FAILURE; + } + return SKB_NOT_DROPPED_YET; +} +EXPORT_SYMBOL(tcp_inbound_md5_hash); + +#endif + +void tcp_done(struct sock *sk) +{ + struct request_sock *req; + + /* We might be called with a new socket, after + * inet_csk_prepare_forced_close() has been called + * so we can not use lockdep_sock_is_held(sk) + */ + req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk, 1); + + if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) + TCP_INC_STATS(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); + + WRITE_ONCE(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); + +int tcp_abort(struct sock *sk, int err) +{ + int state = inet_sk_state_load(sk); + + if (state == TCP_NEW_SYN_RECV) { + struct request_sock *req = inet_reqsk(sk); + + local_bh_disable(); + inet_csk_reqsk_queue_drop(req->rsk_listener, req); + local_bh_enable(); + return 0; + } + if (state == TCP_TIME_WAIT) { + struct inet_timewait_sock *tw = inet_twsk(sk); + + refcount_inc(&tw->tw_refcnt); + local_bh_disable(); + inet_twsk_deschedule_put(tw); + local_bh_enable(); + return 0; + } + + /* Don't race with userspace socket closes such as tcp_close. */ + lock_sock(sk); + + if (sk->sk_state == TCP_LISTEN) { + tcp_set_state(sk, TCP_CLOSE); + inet_csk_listen_stop(sk); + } + + /* Don't race with BH socket closes such as inet_csk_listen_stop. */ + local_bh_disable(); + bh_lock_sock(sk); + + if (!sock_flag(sk, SOCK_DEAD)) { + sk->sk_err = err; + /* This barrier is coupled with smp_rmb() in tcp_poll() */ + smp_wmb(); + sk_error_report(sk); + if (tcp_need_reset(sk->sk_state)) + tcp_send_active_reset(sk, GFP_ATOMIC); + tcp_done(sk); + } + + bh_unlock_sock(sk); + local_bh_enable(); + tcp_write_queue_purge(sk); + release_sock(sk); + return 0; +} +EXPORT_SYMBOL_GPL(tcp_abort); + +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() / 16; + + limit = max(limit, 128UL); + sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */ + sysctl_tcp_mem[1] = limit; /* 6.25 % */ + sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */ +} + +void __init tcp_init(void) +{ + int max_rshare, max_wshare, cnt; + unsigned long limit; + unsigned int i; + + BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE); + BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > + sizeof_field(struct sk_buff, cb)); + + percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL); + + timer_setup(&tcp_orphan_timer, tcp_orphan_update, TIMER_DEFERRABLE); + mod_timer(&tcp_orphan_timer, jiffies + TCP_ORPHAN_TIMER_PERIOD); + + inet_hashinfo2_init(&tcp_hashinfo, "tcp_listen_portaddr_hash", + thash_entries, 21, /* one slot per 2 MB*/ + 0, 64 * 1024); + tcp_hashinfo.bind_bucket_cachep = + kmem_cache_create("tcp_bind_bucket", + sizeof(struct inet_bind_bucket), 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC | + SLAB_ACCOUNT, + NULL); + tcp_hashinfo.bind2_bucket_cachep = + kmem_cache_create("tcp_bind2_bucket", + sizeof(struct inet_bind2_bucket), 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC | + SLAB_ACCOUNT, + 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", + 2 * 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; + tcp_hashinfo.bhash2 = tcp_hashinfo.bhash + 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); + spin_lock_init(&tcp_hashinfo.bhash2[i].lock); + INIT_HLIST_HEAD(&tcp_hashinfo.bhash2[i].chain); + } + + tcp_hashinfo.pernet = false; + + cnt = tcp_hashinfo.ehash_mask + 1; + sysctl_tcp_max_orphans = cnt / 2; + + 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); + + init_net.ipv4.sysctl_tcp_wmem[0] = PAGE_SIZE; + init_net.ipv4.sysctl_tcp_wmem[1] = 16*1024; + init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare); + + init_net.ipv4.sysctl_tcp_rmem[0] = PAGE_SIZE; + init_net.ipv4.sysctl_tcp_rmem[1] = 131072; + init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare); + + pr_info("Hash tables configured (established %u bind %u)\n", + tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); + + tcp_v4_init(); + tcp_metrics_init(); + BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0); + tcp_tasklet_init(); + mptcp_init(); +} |