diff options
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 3431 |
1 files changed, 3431 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c new file mode 100644 index 00000000..30eda52c --- /dev/null +++ b/net/ipv4/tcp.c @@ -0,0 +1,3431 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Implementation of the Transmission Control Protocol(TCP). + * + * Authors: Ross Biro + * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> + * Mark Evans, <evansmp@uhura.aston.ac.uk> + * Corey Minyard <wf-rch!minyard@relay.EU.net> + * Florian La Roche, <flla@stud.uni-sb.de> + * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> + * Linus Torvalds, <torvalds@cs.helsinki.fi> + * Alan Cox, <gw4pts@gw4pts.ampr.org> + * Matthew Dillon, <dillon@apollo.west.oic.com> + * Arnt Gulbrandsen, <agulbra@nvg.unit.no> + * Jorge Cwik, <jorge@laser.satlink.net> + * + * Fixes: + * Alan Cox : Numerous verify_area() calls + * Alan Cox : Set the ACK bit on a reset + * Alan Cox : Stopped it crashing if it closed while + * sk->inuse=1 and was trying to connect + * (tcp_err()). + * Alan Cox : All icmp error handling was broken + * pointers passed where wrong and the + * socket was looked up backwards. Nobody + * tested any icmp error code obviously. + * Alan Cox : tcp_err() now handled properly. It + * wakes people on errors. poll + * behaves and the icmp error race + * has gone by moving it into sock.c + * Alan Cox : tcp_send_reset() fixed to work for + * everything not just packets for + * unknown sockets. + * Alan Cox : tcp option processing. + * Alan Cox : Reset tweaked (still not 100%) [Had + * syn rule wrong] + * Herp Rosmanith : More reset fixes + * Alan Cox : No longer acks invalid rst frames. + * Acking any kind of RST is right out. + * Alan Cox : Sets an ignore me flag on an rst + * receive otherwise odd bits of prattle + * escape still + * Alan Cox : Fixed another acking RST frame bug. + * Should stop LAN workplace lockups. + * Alan Cox : Some tidyups using the new skb list + * facilities + * Alan Cox : sk->keepopen now seems to work + * Alan Cox : Pulls options out correctly on accepts + * Alan Cox : Fixed assorted sk->rqueue->next errors + * Alan Cox : PSH doesn't end a TCP read. Switched a + * bit to skb ops. + * Alan Cox : Tidied tcp_data to avoid a potential + * nasty. + * Alan Cox : Added some better commenting, as the + * tcp is hard to follow + * Alan Cox : Removed incorrect check for 20 * psh + * Michael O'Reilly : ack < copied bug fix. + * Johannes Stille : Misc tcp fixes (not all in yet). + * Alan Cox : FIN with no memory -> CRASH + * Alan Cox : Added socket option proto entries. + * Also added awareness of them to accept. + * Alan Cox : Added TCP options (SOL_TCP) + * Alan Cox : Switched wakeup calls to callbacks, + * so the kernel can layer network + * sockets. + * Alan Cox : Use ip_tos/ip_ttl settings. + * Alan Cox : Handle FIN (more) properly (we hope). + * Alan Cox : RST frames sent on unsynchronised + * state ack error. + * Alan Cox : Put in missing check for SYN bit. + * Alan Cox : Added tcp_select_window() aka NET2E + * window non shrink trick. + * Alan Cox : Added a couple of small NET2E timer + * fixes + * Charles Hedrick : TCP fixes + * Toomas Tamm : TCP window fixes + * Alan Cox : Small URG fix to rlogin ^C ack fight + * Charles Hedrick : Rewrote most of it to actually work + * Linus : Rewrote tcp_read() and URG handling + * completely + * Gerhard Koerting: Fixed some missing timer handling + * Matthew Dillon : Reworked TCP machine states as per RFC + * Gerhard Koerting: PC/TCP workarounds + * Adam Caldwell : Assorted timer/timing errors + * Matthew Dillon : Fixed another RST bug + * Alan Cox : Move to kernel side addressing changes. + * Alan Cox : Beginning work on TCP fastpathing + * (not yet usable) + * Arnt Gulbrandsen: Turbocharged tcp_check() routine. + * Alan Cox : TCP fast path debugging + * Alan Cox : Window clamping + * Michael Riepe : Bug in tcp_check() + * Matt Dillon : More TCP improvements and RST bug fixes + * Matt Dillon : Yet more small nasties remove from the + * TCP code (Be very nice to this man if + * tcp finally works 100%) 8) + * Alan Cox : BSD accept semantics. + * Alan Cox : Reset on closedown bug. + * Peter De Schrijver : ENOTCONN check missing in tcp_sendto(). + * Michael Pall : Handle poll() after URG properly in + * all cases. + * Michael Pall : Undo the last fix in tcp_read_urg() + * (multi URG PUSH broke rlogin). + * Michael Pall : Fix the multi URG PUSH problem in + * tcp_readable(), poll() after URG + * works now. + * Michael Pall : recv(...,MSG_OOB) never blocks in the + * BSD api. + * Alan Cox : Changed the semantics of sk->socket to + * fix a race and a signal problem with + * accept() and async I/O. + * Alan Cox : Relaxed the rules on tcp_sendto(). + * Yury Shevchuk : Really fixed accept() blocking problem. + * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for + * clients/servers which listen in on + * fixed ports. + * Alan Cox : Cleaned the above up and shrank it to + * a sensible code size. + * Alan Cox : Self connect lockup fix. + * Alan Cox : No connect to multicast. + * Ross Biro : Close unaccepted children on master + * socket close. + * Alan Cox : Reset tracing code. + * Alan Cox : Spurious resets on shutdown. + * Alan Cox : Giant 15 minute/60 second timer error + * Alan Cox : Small whoops in polling before an + * accept. + * Alan Cox : Kept the state trace facility since + * it's handy for debugging. + * Alan Cox : More reset handler fixes. + * Alan Cox : Started rewriting the code based on + * the RFC's for other useful protocol + * references see: Comer, KA9Q NOS, and + * for a reference on the difference + * between specifications and how BSD + * works see the 4.4lite source. + * A.N.Kuznetsov : Don't time wait on completion of tidy + * close. + * Linus Torvalds : Fin/Shutdown & copied_seq changes. + * Linus Torvalds : Fixed BSD port reuse to work first syn + * Alan Cox : Reimplemented timers as per the RFC + * and using multiple timers for sanity. + * Alan Cox : Small bug fixes, and a lot of new + * comments. + * Alan Cox : Fixed dual reader crash by locking + * the buffers (much like datagram.c) + * Alan Cox : Fixed stuck sockets in probe. A probe + * now gets fed up of retrying without + * (even a no space) answer. + * Alan Cox : Extracted closing code better + * Alan Cox : Fixed the closing state machine to + * resemble the RFC. + * Alan Cox : More 'per spec' fixes. + * Jorge Cwik : Even faster checksumming. + * Alan Cox : tcp_data() doesn't ack illegal PSH + * only frames. At least one pc tcp stack + * generates them. + * Alan Cox : Cache last socket. + * Alan Cox : Per route irtt. + * Matt Day : poll()->select() match BSD precisely on error + * Alan Cox : New buffers + * Marc Tamsky : Various sk->prot->retransmits and + * sk->retransmits misupdating fixed. + * Fixed tcp_write_timeout: stuck close, + * and TCP syn retries gets used now. + * Mark Yarvis : In tcp_read_wakeup(), don't send an + * ack if state is TCP_CLOSED. + * Alan Cox : Look up device on a retransmit - routes may + * change. Doesn't yet cope with MSS shrink right + * but it's a start! + * Marc Tamsky : Closing in closing fixes. + * Mike Shaver : RFC1122 verifications. + * Alan Cox : rcv_saddr errors. + * Alan Cox : Block double connect(). + * Alan Cox : Small hooks for enSKIP. + * Alexey Kuznetsov: Path MTU discovery. + * Alan Cox : Support soft errors. + * Alan Cox : Fix MTU discovery pathological case + * when the remote claims no mtu! + * Marc Tamsky : TCP_CLOSE fix. + * Colin (G3TNE) : Send a reset on syn ack replies in + * window but wrong (fixes NT lpd problems) + * Pedro Roque : Better TCP window handling, delayed ack. + * Joerg Reuter : No modification of locked buffers in + * tcp_do_retransmit() + * Eric Schenk : Changed receiver side silly window + * avoidance algorithm to BSD style + * algorithm. This doubles throughput + * against machines running Solaris, + * and seems to result in general + * improvement. + * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD + * Willy Konynenberg : Transparent proxying support. + * Mike McLagan : Routing by source + * Keith Owens : Do proper merging with partial SKB's in + * tcp_do_sendmsg to avoid burstiness. + * Eric Schenk : Fix fast close down bug with + * shutdown() followed by close(). + * Andi Kleen : Make poll agree with SIGIO + * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and + * lingertime == 0 (RFC 793 ABORT Call) + * Hirokazu Takahashi : Use copy_from_user() instead of + * csum_and_copy_from_user() if possible. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or(at your option) any later version. + * + * Description of States: + * + * TCP_SYN_SENT sent a connection request, waiting for ack + * + * TCP_SYN_RECV received a connection request, sent ack, + * waiting for final ack in three-way handshake. + * + * TCP_ESTABLISHED connection established + * + * TCP_FIN_WAIT1 our side has shutdown, waiting to complete + * transmission of remaining buffered data + * + * TCP_FIN_WAIT2 all buffered data sent, waiting for remote + * to shutdown + * + * TCP_CLOSING both sides have shutdown but we still have + * data we have to finish sending + * + * TCP_TIME_WAIT timeout to catch resent junk before entering + * closed, can only be entered from FIN_WAIT2 + * or CLOSING. Required because the other end + * may not have gotten our last ACK causing it + * to retransmit the data packet (which we ignore) + * + * TCP_CLOSE_WAIT remote side has shutdown and is waiting for + * us to finish writing our data and to shutdown + * (we have to close() to move on to LAST_ACK) + * + * TCP_LAST_ACK out side has shutdown after remote has + * shutdown. There may still be data in our + * buffer that we have to finish sending + * + * TCP_CLOSE socket is finished + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/fcntl.h> +#include <linux/poll.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/skbuff.h> +#include <linux/scatterlist.h> +#include <linux/splice.h> +#include <linux/net.h> +#include <linux/socket.h> +#include <linux/random.h> +#include <linux/bootmem.h> +#include <linux/highmem.h> +#include <linux/swap.h> +#include <linux/cache.h> +#include <linux/err.h> +#include <linux/crypto.h> +#include <linux/time.h> +#include <linux/slab.h> +#include <linux/uid_stat.h> + +#include <net/icmp.h> +#include <net/tcp.h> +#include <net/xfrm.h> +#include <net/ip.h> +#include <net/ip6_route.h> +#include <net/ipv6.h> +#include <net/transp_v6.h> +#include <net/netdma.h> +#include <net/sock.h> + +#include <asm/uaccess.h> +#include <asm/ioctls.h> + +int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; + +struct percpu_counter tcp_orphan_count; +EXPORT_SYMBOL_GPL(tcp_orphan_count); + +long sysctl_tcp_mem[3] __read_mostly; +int sysctl_tcp_wmem[3] __read_mostly; +int sysctl_tcp_rmem[3] __read_mostly; + +EXPORT_SYMBOL(sysctl_tcp_mem); +EXPORT_SYMBOL(sysctl_tcp_rmem); +EXPORT_SYMBOL(sysctl_tcp_wmem); + +atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ +EXPORT_SYMBOL(tcp_memory_allocated); + +/* + * Current number of TCP sockets. + */ +struct percpu_counter tcp_sockets_allocated; +EXPORT_SYMBOL(tcp_sockets_allocated); + +/* + * TCP splice context + */ +struct tcp_splice_state { + struct pipe_inode_info *pipe; + size_t len; + unsigned int flags; +}; + +/* + * Pressure flag: try to collapse. + * Technical note: it is used by multiple contexts non atomically. + * All the __sk_mem_schedule() is of this nature: accounting + * is strict, actions are advisory and have some latency. + */ +int tcp_memory_pressure __read_mostly; +EXPORT_SYMBOL(tcp_memory_pressure); + +void tcp_enter_memory_pressure(struct sock *sk) +{ + if (!tcp_memory_pressure) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); + tcp_memory_pressure = 1; + } +} +EXPORT_SYMBOL(tcp_enter_memory_pressure); + +/* Convert seconds to retransmits based on initial and max timeout */ +static u8 secs_to_retrans(int seconds, int timeout, int rto_max) +{ + u8 res = 0; + + if (seconds > 0) { + int period = timeout; + + res = 1; + while (seconds > period && res < 255) { + res++; + timeout <<= 1; + if (timeout > rto_max) + timeout = rto_max; + period += timeout; + } + } + return res; +} + +/* Convert retransmits to seconds based on initial and max timeout */ +static int retrans_to_secs(u8 retrans, int timeout, int rto_max) +{ + int period = 0; + + if (retrans > 0) { + period = timeout; + while (--retrans) { + timeout <<= 1; + if (timeout > rto_max) + timeout = rto_max; + period += timeout; + } + } + return period; +} + +/* + * Wait for a TCP event. + * + * Note that we don't need to lock the socket, as the upper poll layers + * take care of normal races (between the test and the event) and we don't + * go look at any of the socket buffers directly. + */ +unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) +{ + unsigned int mask; + struct sock *sk = sock->sk; + struct tcp_sock *tp = tcp_sk(sk); + + sock_poll_wait(file, sk_sleep(sk), wait); + if (sk->sk_state == TCP_LISTEN) + return inet_csk_listen_poll(sk); + + /* Socket is not locked. We are protected from async events + * by poll logic and correct handling of state changes + * made by other threads is impossible in any case. + */ + + mask = 0; + + /* + * POLLHUP is certainly not done right. But poll() doesn't + * have a notion of HUP in just one direction, and for a + * socket the read side is more interesting. + * + * Some poll() documentation says that POLLHUP is incompatible + * with the POLLOUT/POLLWR flags, so somebody should check this + * all. But careful, it tends to be safer to return too many + * bits than too few, and you can easily break real applications + * if you don't tell them that something has hung up! + * + * Check-me. + * + * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and + * our fs/select.c). It means that after we received EOF, + * poll always returns immediately, making impossible poll() on write() + * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP + * if and only if shutdown has been made in both directions. + * Actually, it is interesting to look how Solaris and DUX + * solve this dilemma. I would prefer, if POLLHUP were maskable, + * then we could set it on SND_SHUTDOWN. BTW examples given + * in Stevens' books assume exactly this behaviour, it explains + * why POLLHUP is incompatible with POLLOUT. --ANK + * + * NOTE. Check for TCP_CLOSE is added. The goal is to prevent + * blocking on fresh not-connected or disconnected socket. --ANK + */ + if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) + mask |= POLLHUP; + if (sk->sk_shutdown & RCV_SHUTDOWN) + mask |= POLLIN | POLLRDNORM | POLLRDHUP; + + /* Connected? */ + if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { + int target = sock_rcvlowat(sk, 0, INT_MAX); + + if (tp->urg_seq == tp->copied_seq && + !sock_flag(sk, SOCK_URGINLINE) && + tp->urg_data) + target++; + + /* Potential race condition. If read of tp below will + * escape above sk->sk_state, we can be illegally awaken + * in SYN_* states. */ + if (tp->rcv_nxt - tp->copied_seq >= target) + mask |= POLLIN | POLLRDNORM; + + if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { + if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { + mask |= POLLOUT | POLLWRNORM; + } else { /* send SIGIO later */ + set_bit(SOCK_ASYNC_NOSPACE, + &sk->sk_socket->flags); + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + + /* Race breaker. If space is freed after + * wspace test but before the flags are set, + * IO signal will be lost. + */ + if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) + mask |= POLLOUT | POLLWRNORM; + } + } else + mask |= POLLOUT | POLLWRNORM; + + if (tp->urg_data & TCP_URG_VALID) + mask |= POLLPRI; + } + /* This barrier is coupled with smp_wmb() in tcp_reset() */ + smp_rmb(); + if (sk->sk_err) + mask |= POLLERR; + + return mask; +} +EXPORT_SYMBOL(tcp_poll); + +int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) +{ + struct tcp_sock *tp = tcp_sk(sk); + int answ; + + switch (cmd) { + case SIOCINQ: + if (sk->sk_state == TCP_LISTEN) + return -EINVAL; + + lock_sock(sk); + if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) + answ = 0; + else if (sock_flag(sk, SOCK_URGINLINE) || + !tp->urg_data || + before(tp->urg_seq, tp->copied_seq) || + !before(tp->urg_seq, tp->rcv_nxt)) { + struct sk_buff *skb; + + answ = tp->rcv_nxt - tp->copied_seq; + + /* Subtract 1, if FIN is in queue. */ + skb = skb_peek_tail(&sk->sk_receive_queue); + if (answ && skb) + answ -= tcp_hdr(skb)->fin; + } else + answ = tp->urg_seq - tp->copied_seq; + release_sock(sk); + break; + case SIOCATMARK: + answ = tp->urg_data && tp->urg_seq == tp->copied_seq; + break; + case SIOCOUTQ: + if (sk->sk_state == TCP_LISTEN) + return -EINVAL; + + if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) + answ = 0; + else + answ = tp->write_seq - tp->snd_una; + break; + case SIOCOUTQNSD: + if (sk->sk_state == TCP_LISTEN) + return -EINVAL; + + if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) + answ = 0; + else + answ = tp->write_seq - tp->snd_nxt; + break; + default: + return -ENOIOCTLCMD; + } + + return put_user(answ, (int __user *)arg); +} +EXPORT_SYMBOL(tcp_ioctl); + +static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) +{ + TCP_SKB_CB(skb)->flags |= TCPHDR_PSH; + tp->pushed_seq = tp->write_seq; +} + +static inline int forced_push(struct tcp_sock *tp) +{ + return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); +} + +static inline void skb_entail(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); + + skb->csum = 0; + tcb->seq = tcb->end_seq = tp->write_seq; + tcb->flags = TCPHDR_ACK; + tcb->sacked = 0; + skb_header_release(skb); + tcp_add_write_queue_tail(sk, skb); + sk->sk_wmem_queued += skb->truesize; + sk_mem_charge(sk, skb->truesize); + if (tp->nonagle & TCP_NAGLE_PUSH) + tp->nonagle &= ~TCP_NAGLE_PUSH; +} + +static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) +{ + if (flags & MSG_OOB) + tp->snd_up = tp->write_seq; +} + +static inline void tcp_push(struct sock *sk, int flags, int mss_now, + int nonagle) +{ + if (tcp_send_head(sk)) { + struct tcp_sock *tp = tcp_sk(sk); + + if (!(flags & MSG_MORE) || forced_push(tp)) + tcp_mark_push(tp, tcp_write_queue_tail(sk)); + + tcp_mark_urg(tp, flags); + __tcp_push_pending_frames(sk, mss_now, + (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); + } +} + +static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, + unsigned int offset, size_t len) +{ + struct tcp_splice_state *tss = rd_desc->arg.data; + int ret; + + ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), + tss->flags); + if (ret > 0) + rd_desc->count -= ret; + return ret; +} + +static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) +{ + /* Store TCP splice context information in read_descriptor_t. */ + read_descriptor_t rd_desc = { + .arg.data = tss, + .count = tss->len, + }; + + return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); +} + +/** + * tcp_splice_read - splice data from TCP socket to a pipe + * @sock: socket to splice from + * @ppos: position (not valid) + * @pipe: pipe to splice to + * @len: number of bytes to splice + * @flags: splice modifier flags + * + * Description: + * Will read pages from given socket and fill them into a pipe. + * + **/ +ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + struct sock *sk = sock->sk; + struct tcp_splice_state tss = { + .pipe = pipe, + .len = len, + .flags = flags, + }; + long timeo; + ssize_t spliced; + int ret; + + sock_rps_record_flow(sk); + /* + * We can't seek on a socket input + */ + if (unlikely(*ppos)) + return -ESPIPE; + + ret = spliced = 0; + + lock_sock(sk); + + timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); + while (tss.len) { + ret = __tcp_splice_read(sk, &tss); + if (ret < 0) + break; + else if (!ret) { + if (spliced) + break; + if (sock_flag(sk, SOCK_DONE)) + break; + if (sk->sk_err) { + ret = sock_error(sk); + break; + } + if (sk->sk_shutdown & RCV_SHUTDOWN) + break; + if (sk->sk_state == TCP_CLOSE) { + /* + * This occurs when user tries to read + * from never connected socket. + */ + if (!sock_flag(sk, SOCK_DONE)) + ret = -ENOTCONN; + break; + } + if (!timeo) { + ret = -EAGAIN; + break; + } + sk_wait_data(sk, &timeo); + if (signal_pending(current)) { + ret = sock_intr_errno(timeo); + break; + } + continue; + } + tss.len -= ret; + spliced += ret; + + if (!timeo) + break; + release_sock(sk); + lock_sock(sk); + + if (sk->sk_err || sk->sk_state == TCP_CLOSE || + (sk->sk_shutdown & RCV_SHUTDOWN) || + signal_pending(current)) + break; + } + + release_sock(sk); + + if (spliced) + return spliced; + + return ret; +} +EXPORT_SYMBOL(tcp_splice_read); + +struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) +{ + struct sk_buff *skb; + + /* The TCP header must be at least 32-bit aligned. */ + size = ALIGN(size, 4); + + skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); + if (skb) { + if (sk_wmem_schedule(sk, skb->truesize)) { + /* + * Make sure that we have exactly size bytes + * available to the caller, no more, no less. + */ + skb_reserve(skb, skb_tailroom(skb) - size); + return skb; + } + __kfree_skb(skb); + } else { + sk->sk_prot->enter_memory_pressure(sk); + sk_stream_moderate_sndbuf(sk); + } + return NULL; +} + +static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, + int large_allowed) +{ + struct tcp_sock *tp = tcp_sk(sk); + u32 xmit_size_goal, old_size_goal; + + xmit_size_goal = mss_now; + + if (large_allowed && sk_can_gso(sk)) { + xmit_size_goal = ((sk->sk_gso_max_size - 1) - + inet_csk(sk)->icsk_af_ops->net_header_len - + inet_csk(sk)->icsk_ext_hdr_len - + tp->tcp_header_len); + + xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal); + + /* We try hard to avoid divides here */ + old_size_goal = tp->xmit_size_goal_segs * mss_now; + + if (likely(old_size_goal <= xmit_size_goal && + old_size_goal + mss_now > xmit_size_goal)) { + xmit_size_goal = old_size_goal; + } else { + tp->xmit_size_goal_segs = xmit_size_goal / mss_now; + xmit_size_goal = tp->xmit_size_goal_segs * mss_now; + } + } + + return max(xmit_size_goal, mss_now); +} + +static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) +{ + int mss_now; + + mss_now = tcp_current_mss(sk); + *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); + + return mss_now; +} + +static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, + size_t psize, int flags) +{ + struct tcp_sock *tp = tcp_sk(sk); + int mss_now, size_goal; + int err; + ssize_t copied; + long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); + + /* Wait for a connection to finish. */ + if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) + if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) + goto out_err; + + clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); + + mss_now = tcp_send_mss(sk, &size_goal, flags); + copied = 0; + + err = -EPIPE; + if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) + goto out_err; + + while (psize > 0) { + struct sk_buff *skb = tcp_write_queue_tail(sk); + struct page *page = pages[poffset / PAGE_SIZE]; + int copy, i, can_coalesce; + int offset = poffset % PAGE_SIZE; + int size = min_t(size_t, psize, PAGE_SIZE - offset); + + if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { +new_segment: + if (!sk_stream_memory_free(sk)) + goto wait_for_sndbuf; + + skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); + if (!skb) + goto wait_for_memory; + + skb_entail(sk, skb); + copy = size_goal; + } + + if (copy > size) + copy = size; + + i = skb_shinfo(skb)->nr_frags; + can_coalesce = skb_can_coalesce(skb, i, page, offset); + if (!can_coalesce && i >= MAX_SKB_FRAGS) { + tcp_mark_push(tp, skb); + goto new_segment; + } + if (!sk_wmem_schedule(sk, copy)) + goto wait_for_memory; + + if (can_coalesce) { + skb_shinfo(skb)->frags[i - 1].size += copy; + } else { + get_page(page); + skb_fill_page_desc(skb, i, page, offset, copy); + } + + skb->len += copy; + skb->data_len += copy; + skb->truesize += copy; + sk->sk_wmem_queued += copy; + sk_mem_charge(sk, copy); + skb->ip_summed = CHECKSUM_PARTIAL; + tp->write_seq += copy; + TCP_SKB_CB(skb)->end_seq += copy; + skb_shinfo(skb)->gso_segs = 0; + + if (!copied) + TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH; + + copied += copy; + poffset += copy; + if (!(psize -= copy)) + goto out; + + if (skb->len < size_goal || (flags & MSG_OOB)) + continue; + + if (forced_push(tp)) { + tcp_mark_push(tp, skb); + __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); + } else if (skb == tcp_send_head(sk)) + tcp_push_one(sk, mss_now); + continue; + +wait_for_sndbuf: + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); +wait_for_memory: + tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); + + if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) + goto do_error; + + mss_now = tcp_send_mss(sk, &size_goal, flags); + } + +out: + if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) + tcp_push(sk, flags, mss_now, tp->nonagle); + return copied; + +do_error: + if (copied) + goto out; +out_err: + return sk_stream_error(sk, flags, err); +} + +int tcp_sendpage(struct sock *sk, struct page *page, int offset, + size_t size, int flags) +{ + ssize_t res; + + if (!(sk->sk_route_caps & NETIF_F_SG) || + !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) + return sock_no_sendpage(sk->sk_socket, page, offset, size, + flags); + + lock_sock(sk); + res = do_tcp_sendpages(sk, &page, offset, size, flags); + release_sock(sk); + return res; +} +EXPORT_SYMBOL(tcp_sendpage); + +#define TCP_PAGE(sk) (sk->sk_sndmsg_page) +#define TCP_OFF(sk) (sk->sk_sndmsg_off) + +static inline int select_size(struct sock *sk, int sg) +{ + struct tcp_sock *tp = tcp_sk(sk); + int tmp = tp->mss_cache; + + if (sg) { + if (sk_can_gso(sk)) + tmp = 0; + else { + int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); + + if (tmp >= pgbreak && + tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) + tmp = pgbreak; + } + } + + return tmp; +} + +int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, + size_t size) +{ + struct iovec *iov; + struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *skb; + int iovlen, flags; + int mss_now, size_goal; + int sg, err, copied; + long timeo; + + lock_sock(sk); + + flags = msg->msg_flags; + timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); + + /* Wait for a connection to finish. */ + if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) + if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) + goto out_err; + + /* This should be in poll */ + clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); + + mss_now = tcp_send_mss(sk, &size_goal, flags); + + /* Ok commence sending. */ + iovlen = msg->msg_iovlen; + iov = msg->msg_iov; + copied = 0; + + err = -EPIPE; + if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) + goto out_err; + + sg = sk->sk_route_caps & NETIF_F_SG; + + while (--iovlen >= 0) { + size_t seglen = iov->iov_len; + unsigned char __user *from = iov->iov_base; + + iov++; + + while (seglen > 0) { + int copy = 0; + int max = size_goal; + + skb = tcp_write_queue_tail(sk); + if (tcp_send_head(sk)) { + if (skb->ip_summed == CHECKSUM_NONE) + max = mss_now; + copy = max - skb->len; + } + + if (copy <= 0) { +new_segment: + /* Allocate new segment. If the interface is SG, + * allocate skb fitting to single page. + */ + if (!sk_stream_memory_free(sk)) + goto wait_for_sndbuf; + + skb = sk_stream_alloc_skb(sk, + select_size(sk, sg), + sk->sk_allocation); + if (!skb) + goto wait_for_memory; + + /* + * Check whether we can use HW checksum. + */ + if (sk->sk_route_caps & NETIF_F_ALL_CSUM) + skb->ip_summed = CHECKSUM_PARTIAL; + + skb_entail(sk, skb); + copy = size_goal; + max = size_goal; + } + + /* Try to append data to the end of skb. */ + if (copy > seglen) + copy = seglen; + + /* Where to copy to? */ + if (skb_tailroom(skb) > 0) { + /* We have some space in skb head. Superb! */ + if (copy > skb_tailroom(skb)) + copy = skb_tailroom(skb); + err = skb_add_data_nocache(sk, skb, from, copy); + if (err) + goto do_fault; + } else { + int merge = 0; + int i = skb_shinfo(skb)->nr_frags; + struct page *page = TCP_PAGE(sk); + int off = TCP_OFF(sk); + + if (skb_can_coalesce(skb, i, page, off) && + off != PAGE_SIZE) { + /* We can extend the last page + * fragment. */ + merge = 1; + } else if (i == MAX_SKB_FRAGS || !sg) { + /* Need to add new fragment and cannot + * do this because interface is non-SG, + * or because all the page slots are + * busy. */ + tcp_mark_push(tp, skb); + goto new_segment; + } else if (page) { + if (off == PAGE_SIZE) { + put_page(page); + TCP_PAGE(sk) = page = NULL; + off = 0; + } + } else + off = 0; + + if (copy > PAGE_SIZE - off) + copy = PAGE_SIZE - off; + + if (!sk_wmem_schedule(sk, copy)) + goto wait_for_memory; + + if (!page) { + /* Allocate new cache page. */ + if (!(page = sk_stream_alloc_page(sk))) + goto wait_for_memory; + } + + /* Time to copy data. We are close to + * the end! */ + err = skb_copy_to_page_nocache(sk, from, skb, + page, off, copy); + if (err) { + /* If this page was new, give it to the + * socket so it does not get leaked. + */ + if (!TCP_PAGE(sk)) { + TCP_PAGE(sk) = page; + TCP_OFF(sk) = 0; + } + goto do_error; + } + + /* Update the skb. */ + if (merge) { + skb_shinfo(skb)->frags[i - 1].size += + copy; + } else { + skb_fill_page_desc(skb, i, page, off, copy); + if (TCP_PAGE(sk)) { + get_page(page); + } else if (off + copy < PAGE_SIZE) { + get_page(page); + TCP_PAGE(sk) = page; + } + } + + TCP_OFF(sk) = off + copy; + } + + if (!copied) + TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH; + + tp->write_seq += copy; + TCP_SKB_CB(skb)->end_seq += copy; + skb_shinfo(skb)->gso_segs = 0; + + from += copy; + copied += copy; + if ((seglen -= copy) == 0 && iovlen == 0) + goto out; + + if (skb->len < max || (flags & MSG_OOB)) + continue; + + if (forced_push(tp)) { + tcp_mark_push(tp, skb); + __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); + } else if (skb == tcp_send_head(sk)) + tcp_push_one(sk, mss_now); + continue; + +wait_for_sndbuf: + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); +wait_for_memory: + if (copied) + tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); + + if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) + goto do_error; + + mss_now = tcp_send_mss(sk, &size_goal, flags); + } + } + +out: + if (copied) + tcp_push(sk, flags, mss_now, tp->nonagle); + release_sock(sk); + + if (copied > 0) + uid_stat_tcp_snd(current_uid(), copied); + return copied; + +do_fault: + if (!skb->len) { + tcp_unlink_write_queue(skb, sk); + /* It is the one place in all of TCP, except connection + * reset, where we can be unlinking the send_head. + */ + tcp_check_send_head(sk, skb); + sk_wmem_free_skb(sk, skb); + } + +do_error: + if (copied) + goto out; +out_err: + err = sk_stream_error(sk, flags, err); + release_sock(sk); + return err; +} +EXPORT_SYMBOL(tcp_sendmsg); + +/* + * Handle reading urgent data. BSD has very simple semantics for + * this, no blocking and very strange errors 8) + */ + +static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) +{ + struct tcp_sock *tp = tcp_sk(sk); + + /* No URG data to read. */ + if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || + tp->urg_data == TCP_URG_READ) + return -EINVAL; /* Yes this is right ! */ + + if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) + return -ENOTCONN; + + if (tp->urg_data & TCP_URG_VALID) { + int err = 0; + char c = tp->urg_data; + + if (!(flags & MSG_PEEK)) + tp->urg_data = TCP_URG_READ; + + /* Read urgent data. */ + msg->msg_flags |= MSG_OOB; + + if (len > 0) { + if (!(flags & MSG_TRUNC)) + err = memcpy_toiovec(msg->msg_iov, &c, 1); + len = 1; + } else + msg->msg_flags |= MSG_TRUNC; + + return err ? -EFAULT : len; + } + + if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) + return 0; + + /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and + * the available implementations agree in this case: + * this call should never block, independent of the + * blocking state of the socket. + * Mike <pall@rz.uni-karlsruhe.de> + */ + return -EAGAIN; +} + +/* Clean up the receive buffer for full frames taken by the user, + * then send an ACK if necessary. COPIED is the number of bytes + * tcp_recvmsg has given to the user so far, it speeds up the + * calculation of whether or not we must ACK for the sake of + * a window update. + */ +void tcp_cleanup_rbuf(struct sock *sk, int copied) +{ + struct tcp_sock *tp = tcp_sk(sk); + int time_to_ack = 0; + +#if TCP_DEBUG + struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); + + 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); +#endif + + if (inet_csk_ack_scheduled(sk)) { + const struct inet_connection_sock *icsk = inet_csk(sk); + /* Delayed ACKs frequently hit locked sockets during bulk + * receive. */ + if (icsk->icsk_ack.blocked || + /* Once-per-two-segments ACK was not sent by tcp_input.c */ + tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || + /* + * If this read emptied read buffer, we send ACK, if + * connection is not bidirectional, user drained + * receive buffer and there was a small segment + * in queue. + */ + (copied > 0 && + ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || + ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && + !icsk->icsk_ack.pingpong)) && + !atomic_read(&sk->sk_rmem_alloc))) + time_to_ack = 1; + } + + /* We send an ACK if we can now advertise a non-zero window + * which has been raised "significantly". + * + * Even if window raised up to infinity, do not send window open ACK + * in states, where we will not receive more. It is useless. + */ + if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { + __u32 rcv_window_now = tcp_receive_window(tp); + + /* Optimize, __tcp_select_window() is not cheap. */ + if (2*rcv_window_now <= tp->window_clamp) { + __u32 new_window = __tcp_select_window(sk); + + /* Send ACK now, if this read freed lots of space + * in our buffer. Certainly, new_window is new window. + * We can advertise it now, if it is not less than current one. + * "Lots" means "at least twice" here. + */ + if (new_window && new_window >= 2 * rcv_window_now) + time_to_ack = 1; + } + } + if (time_to_ack) + tcp_send_ack(sk); +} + +static void tcp_prequeue_process(struct sock *sk) +{ + struct sk_buff *skb; + struct tcp_sock *tp = tcp_sk(sk); + + NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); + + /* RX process wants to run with disabled BHs, though it is not + * necessary */ + local_bh_disable(); + while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) + sk_backlog_rcv(sk, skb); + local_bh_enable(); + + /* Clear memory counter. */ + tp->ucopy.memory = 0; +} + +#ifdef CONFIG_NET_DMA +static void tcp_service_net_dma(struct sock *sk, bool wait) +{ + dma_cookie_t done, used; + dma_cookie_t last_issued; + struct tcp_sock *tp = tcp_sk(sk); + + if (!tp->ucopy.dma_chan) + return; + + last_issued = tp->ucopy.dma_cookie; + dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); + + do { + if (dma_async_memcpy_complete(tp->ucopy.dma_chan, + last_issued, &done, + &used) == DMA_SUCCESS) { + /* Safe to free early-copied skbs now */ + __skb_queue_purge(&sk->sk_async_wait_queue); + break; + } else { + struct sk_buff *skb; + while ((skb = skb_peek(&sk->sk_async_wait_queue)) && + (dma_async_is_complete(skb->dma_cookie, done, + used) == DMA_SUCCESS)) { + __skb_dequeue(&sk->sk_async_wait_queue); + kfree_skb(skb); + } + } + } while (wait); +} +#endif + +static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) +{ + struct sk_buff *skb; + u32 offset; + + skb_queue_walk(&sk->sk_receive_queue, skb) { + offset = seq - TCP_SKB_CB(skb)->seq; + if (tcp_hdr(skb)->syn) + offset--; + if (offset < skb->len || tcp_hdr(skb)->fin) { + *off = offset; + return skb; + } + } + return NULL; +} + +/* + * This routine provides an alternative to tcp_recvmsg() for routines + * that would like to handle copying from skbuffs directly in 'sendfile' + * fashion. + * Note: + * - It is assumed that the socket was locked by the caller. + * - The routine does not block. + * - At present, there is no support for reading OOB data + * or for 'peeking' the socket using this routine + * (although both would be easy to implement). + */ +int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor) +{ + struct sk_buff *skb; + struct tcp_sock *tp = tcp_sk(sk); + u32 seq = tp->copied_seq; + u32 offset; + int copied = 0; + + if (sk->sk_state == TCP_LISTEN) + return -ENOTCONN; + while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { + if (offset < skb->len) { + int used; + size_t len; + + len = skb->len - offset; + /* Stop reading if we hit a patch of urgent data */ + if (tp->urg_data) { + u32 urg_offset = tp->urg_seq - seq; + if (urg_offset < len) + len = urg_offset; + if (!len) + break; + } + used = recv_actor(desc, skb, offset, len); + if (used < 0) { + if (!copied) + copied = used; + break; + } else if (used <= len) { + seq += used; + copied += used; + offset += used; + } + /* + * If recv_actor drops the lock (e.g. TCP splice + * receive) the skb pointer might be invalid when + * getting here: tcp_collapse might have deleted it + * while aggregating skbs from the socket queue. + */ + skb = tcp_recv_skb(sk, seq-1, &offset); + if (!skb || (offset+1 != skb->len)) + break; + } + if (tcp_hdr(skb)->fin) { + sk_eat_skb(sk, skb, 0); + ++seq; + break; + } + sk_eat_skb(sk, skb, 0); + if (!desc->count) + break; + tp->copied_seq = seq; + } + tp->copied_seq = seq; + + tcp_rcv_space_adjust(sk); + + /* Clean up data we have read: This will do ACK frames. */ + if (copied > 0) { + tcp_cleanup_rbuf(sk, copied); + uid_stat_tcp_rcv(current_uid(), copied); + } + + return copied; +} +EXPORT_SYMBOL(tcp_read_sock); + +/* + * This routine copies from a sock struct into the user buffer. + * + * Technical note: in 2.3 we work on _locked_ socket, so that + * tricks with *seq access order and skb->users are not required. + * Probably, code can be easily improved even more. + */ + +int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, + size_t len, int nonblock, int flags, int *addr_len) +{ + struct tcp_sock *tp = tcp_sk(sk); + int copied = 0; + u32 peek_seq; + u32 *seq; + unsigned long used; + int err; + int target; /* Read at least this many bytes */ + long timeo; + struct task_struct *user_recv = NULL; + int copied_early = 0; + struct sk_buff *skb; + u32 urg_hole = 0; + + lock_sock(sk); + + err = -ENOTCONN; + if (sk->sk_state == TCP_LISTEN) + goto out; + + timeo = sock_rcvtimeo(sk, nonblock); + + /* Urgent data needs to be handled specially. */ + if (flags & MSG_OOB) + goto recv_urg; + + seq = &tp->copied_seq; + if (flags & MSG_PEEK) { + peek_seq = tp->copied_seq; + seq = &peek_seq; + } + + target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); + +#ifdef CONFIG_NET_DMA + tp->ucopy.dma_chan = NULL; + preempt_disable(); + skb = skb_peek_tail(&sk->sk_receive_queue); + { + int available = 0; + + if (skb) + available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); + if ((available < target) && + (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && + !sysctl_tcp_low_latency && + dma_find_channel(DMA_MEMCPY)) { + preempt_enable_no_resched(); + tp->ucopy.pinned_list = + dma_pin_iovec_pages(msg->msg_iov, len); + } else { + preempt_enable_no_resched(); + } + } +#endif + + do { + u32 offset; + + /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ + if (tp->urg_data && tp->urg_seq == *seq) { + if (copied) + break; + if (signal_pending(current)) { + copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; + break; + } + } + + /* Next get a buffer. */ + + skb_queue_walk(&sk->sk_receive_queue, skb) { + /* Now that we have two receive queues this + * shouldn't happen. + */ + if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), + "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", + *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, + flags)) + break; + + offset = *seq - TCP_SKB_CB(skb)->seq; + if (tcp_hdr(skb)->syn) + offset--; + if (offset < skb->len) + goto found_ok_skb; + if (tcp_hdr(skb)->fin) + goto found_fin_ok; + WARN(!(flags & MSG_PEEK), + "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", + *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); + } + + /* Well, if we have backlog, try to process it now yet. */ + + if (copied >= target && !sk->sk_backlog.tail) + break; + + if (copied) { + if (sk->sk_err || + sk->sk_state == TCP_CLOSE || + (sk->sk_shutdown & RCV_SHUTDOWN) || + !timeo || + signal_pending(current)) + break; + } else { + if (sock_flag(sk, SOCK_DONE)) + break; + + if (sk->sk_err) { + copied = sock_error(sk); + break; + } + + if (sk->sk_shutdown & RCV_SHUTDOWN) + break; + + if (sk->sk_state == TCP_CLOSE) { + if (!sock_flag(sk, SOCK_DONE)) { + /* This occurs when user tries to read + * from never connected socket. + */ + copied = -ENOTCONN; + break; + } + break; + } + + if (!timeo) { + copied = -EAGAIN; + break; + } + + if (signal_pending(current)) { + copied = sock_intr_errno(timeo); + break; + } + } + + tcp_cleanup_rbuf(sk, copied); + + if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { + /* Install new reader */ + if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { + user_recv = current; + tp->ucopy.task = user_recv; + tp->ucopy.iov = msg->msg_iov; + } + + tp->ucopy.len = len; + + WARN_ON(tp->copied_seq != tp->rcv_nxt && + !(flags & (MSG_PEEK | MSG_TRUNC))); + + /* Ugly... If prequeue is not empty, we have to + * process it before releasing socket, otherwise + * order will be broken at second iteration. + * More elegant solution is required!!! + * + * Look: we have the following (pseudo)queues: + * + * 1. packets in flight + * 2. backlog + * 3. prequeue + * 4. receive_queue + * + * Each queue can be processed only if the next ones + * are empty. At this point we have empty receive_queue. + * But prequeue _can_ be not empty after 2nd iteration, + * when we jumped to start of loop because backlog + * processing added something to receive_queue. + * We cannot release_sock(), because backlog contains + * packets arrived _after_ prequeued ones. + * + * Shortly, algorithm is clear --- to process all + * the queues in order. We could make it more directly, + * requeueing packets from backlog to prequeue, if + * is not empty. It is more elegant, but eats cycles, + * unfortunately. + */ + if (!skb_queue_empty(&tp->ucopy.prequeue)) + goto do_prequeue; + + /* __ Set realtime policy in scheduler __ */ + } + +#ifdef CONFIG_NET_DMA + if (tp->ucopy.dma_chan) + dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); +#endif + if (copied >= target) { + /* Do not sleep, just process backlog. */ + release_sock(sk); + lock_sock(sk); + } else + sk_wait_data(sk, &timeo); + +#ifdef CONFIG_NET_DMA + tcp_service_net_dma(sk, false); /* Don't block */ + tp->ucopy.wakeup = 0; +#endif + + if (user_recv) { + int chunk; + + /* __ Restore normal policy in scheduler __ */ + + if ((chunk = len - tp->ucopy.len) != 0) { + NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); + len -= chunk; + copied += chunk; + } + + if (tp->rcv_nxt == tp->copied_seq && + !skb_queue_empty(&tp->ucopy.prequeue)) { +do_prequeue: + tcp_prequeue_process(sk); + + if ((chunk = len - tp->ucopy.len) != 0) { + NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); + len -= chunk; + copied += chunk; + } + } + } + if ((flags & MSG_PEEK) && + (peek_seq - copied - urg_hole != tp->copied_seq)) { + if (net_ratelimit()) + printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", + current->comm, task_pid_nr(current)); + peek_seq = tp->copied_seq; + } + continue; + + found_ok_skb: + /* Ok so how much can we use? */ + used = skb->len - offset; + if (len < used) + used = len; + + /* Do we have urgent data here? */ + if (tp->urg_data) { + u32 urg_offset = tp->urg_seq - *seq; + if (urg_offset < used) { + if (!urg_offset) { + if (!sock_flag(sk, SOCK_URGINLINE)) { + ++*seq; + urg_hole++; + offset++; + used--; + if (!used) + goto skip_copy; + } + } else + used = urg_offset; + } + } + + if (!(flags & MSG_TRUNC)) { +#ifdef CONFIG_NET_DMA + if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) + tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY); + + if (tp->ucopy.dma_chan) { + tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( + tp->ucopy.dma_chan, skb, offset, + msg->msg_iov, used, + tp->ucopy.pinned_list); + + if (tp->ucopy.dma_cookie < 0) { + + printk(KERN_ALERT "dma_cookie < 0\n"); + + /* Exception. Bailout! */ + if (!copied) + copied = -EFAULT; + break; + } + + dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); + + if ((offset + used) == skb->len) + copied_early = 1; + + } else +#endif + { + err = skb_copy_datagram_iovec(skb, offset, + msg->msg_iov, used); + if (err) { + /* Exception. Bailout! */ + if (!copied) + copied = -EFAULT; + break; + } + } + } + + *seq += used; + copied += used; + len -= used; + + tcp_rcv_space_adjust(sk); + +skip_copy: + if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { + tp->urg_data = 0; + tcp_fast_path_check(sk); + } + if (used + offset < skb->len) + continue; + + if (tcp_hdr(skb)->fin) + goto found_fin_ok; + if (!(flags & MSG_PEEK)) { + sk_eat_skb(sk, skb, copied_early); + copied_early = 0; + } + continue; + + found_fin_ok: + /* Process the FIN. */ + ++*seq; + if (!(flags & MSG_PEEK)) { + sk_eat_skb(sk, skb, copied_early); + copied_early = 0; + } + break; + } while (len > 0); + + if (user_recv) { + if (!skb_queue_empty(&tp->ucopy.prequeue)) { + int chunk; + + tp->ucopy.len = copied > 0 ? len : 0; + + tcp_prequeue_process(sk); + + if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { + NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); + len -= chunk; + copied += chunk; + } + } + + tp->ucopy.task = NULL; + tp->ucopy.len = 0; + } + +#ifdef CONFIG_NET_DMA + tcp_service_net_dma(sk, true); /* Wait for queue to drain */ + tp->ucopy.dma_chan = NULL; + + if (tp->ucopy.pinned_list) { + dma_unpin_iovec_pages(tp->ucopy.pinned_list); + tp->ucopy.pinned_list = NULL; + } +#endif + + /* According to UNIX98, msg_name/msg_namelen are ignored + * on connected socket. I was just happy when found this 8) --ANK + */ + + /* Clean up data we have read: This will do ACK frames. */ + tcp_cleanup_rbuf(sk, copied); + + release_sock(sk); + + if (copied > 0) + uid_stat_tcp_rcv(current_uid(), copied); + return copied; + +out: + release_sock(sk); + return err; + +recv_urg: + err = tcp_recv_urg(sk, msg, len, flags); + if (err > 0) + uid_stat_tcp_rcv(current_uid(), err); + goto out; +} +EXPORT_SYMBOL(tcp_recvmsg); + +void tcp_set_state(struct sock *sk, int state) +{ + int oldstate = sk->sk_state; + + switch (state) { + case TCP_ESTABLISHED: + if (oldstate != TCP_ESTABLISHED) + TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); + break; + + case TCP_CLOSE: + if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) + TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); + + sk->sk_prot->unhash(sk); + if (inet_csk(sk)->icsk_bind_hash && + !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) + inet_put_port(sk); + /* fall through */ + default: + if (oldstate == TCP_ESTABLISHED) + TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); + } + + /* Change state AFTER socket is unhashed to avoid closed + * socket sitting in hash tables. + */ + sk->sk_state = state; + +#ifdef STATE_TRACE + SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); +#endif +} +EXPORT_SYMBOL_GPL(tcp_set_state); + +/* + * State processing on a close. This implements the state shift for + * sending our FIN frame. Note that we only send a FIN for some + * states. A shutdown() may have already sent the FIN, or we may be + * closed. + */ + +static const unsigned char new_state[16] = { + /* current state: new state: action: */ + /* (Invalid) */ TCP_CLOSE, + /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, + /* TCP_SYN_SENT */ TCP_CLOSE, + /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, + /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, + /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, + /* TCP_TIME_WAIT */ TCP_CLOSE, + /* TCP_CLOSE */ TCP_CLOSE, + /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, + /* TCP_LAST_ACK */ TCP_LAST_ACK, + /* TCP_LISTEN */ TCP_CLOSE, + /* TCP_CLOSING */ TCP_CLOSING, +}; + +static int tcp_close_state(struct sock *sk) +{ + int next = (int)new_state[sk->sk_state]; + int ns = next & TCP_STATE_MASK; + + tcp_set_state(sk, ns); + + return next & TCP_ACTION_FIN; +} + +/* + * Shutdown the sending side of a connection. Much like close except + * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). + */ + +void tcp_shutdown(struct sock *sk, int how) +{ + /* We need to grab some memory, and put together a FIN, + * and then put it into the queue to be sent. + * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. + */ + if (!(how & SEND_SHUTDOWN)) + return; + + /* If we've already sent a FIN, or it's a closed state, skip this. */ + if ((1 << sk->sk_state) & + (TCPF_ESTABLISHED | TCPF_SYN_SENT | + TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { + /* Clear out any half completed packets. FIN if needed. */ + if (tcp_close_state(sk)) + tcp_send_fin(sk); + } +} +EXPORT_SYMBOL(tcp_shutdown); + +void tcp_close(struct sock *sk, long timeout) +{ + struct sk_buff *skb; + int data_was_unread = 0; + int state; + + lock_sock(sk); + sk->sk_shutdown = SHUTDOWN_MASK; + + if (sk->sk_state == TCP_LISTEN) { + tcp_set_state(sk, TCP_CLOSE); + + /* Special case. */ + inet_csk_listen_stop(sk); + + goto adjudge_to_death; + } + + /* We need to flush the recv. buffs. We do this only on the + * descriptor close, not protocol-sourced closes, because the + * reader process may not have drained the data yet! + */ + while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { + u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - + tcp_hdr(skb)->fin; + data_was_unread += len; + __kfree_skb(skb); + } + + sk_mem_reclaim(sk); + + /* 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 (data_was_unread) { + /* Unread data was tossed, zap the connection. */ + NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); + tcp_set_state(sk, TCP_CLOSE); + tcp_send_active_reset(sk, sk->sk_allocation); + } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { + /* Check zero linger _after_ checking for unread data. */ + sk->sk_prot->disconnect(sk, 0); + NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); + } else if (tcp_close_state(sk)) { + /* We FIN if the application ate all the data before + * zapping the connection. + */ + + /* RED-PEN. Formally speaking, we have broken TCP state + * machine. State transitions: + * + * TCP_ESTABLISHED -> TCP_FIN_WAIT1 + * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) + * TCP_CLOSE_WAIT -> TCP_LAST_ACK + * + * are legal only when FIN has been sent (i.e. in window), + * rather than queued out of window. Purists blame. + * + * F.e. "RFC state" is ESTABLISHED, + * if Linux state is FIN-WAIT-1, but FIN is still not sent. + * + * The visible declinations are that sometimes + * we enter time-wait state, when it is not required really + * (harmless), do not send active resets, when they are + * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when + * they look as CLOSING or LAST_ACK for Linux) + * Probably, I missed some more holelets. + * --ANK + */ + tcp_send_fin(sk); + } + + sk_stream_wait_close(sk, timeout); + +adjudge_to_death: + state = sk->sk_state; + sock_hold(sk); + sock_orphan(sk); + + /* It is the last release_sock in its life. It will remove backlog. */ + release_sock(sk); + + + /* Now socket is owned by kernel and we acquire BH lock + to finish close. No need to check for user refs. + */ + local_bh_disable(); + bh_lock_sock(sk); + WARN_ON(sock_owned_by_user(sk)); + + percpu_counter_inc(sk->sk_prot->orphan_count); + + /* Have we already been destroyed by a softirq or backlog? */ + if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) + goto out; + + /* This is a (useful) BSD violating of the RFC. There is a + * problem with TCP as specified in that the other end could + * keep a socket open forever with no application left this end. + * We use a 3 minute timeout (about the same as BSD) then kill + * our end. If they send after that then tough - BUT: long enough + * that we won't make the old 4*rto = almost no time - whoops + * reset mistake. + * + * Nope, it was not mistake. It is really desired behaviour + * f.e. on http servers, when such sockets are useless, but + * consume significant resources. Let's do it with special + * linger2 option. --ANK + */ + + if (sk->sk_state == TCP_FIN_WAIT2) { + struct tcp_sock *tp = tcp_sk(sk); + if (tp->linger2 < 0) { + tcp_set_state(sk, TCP_CLOSE); + tcp_send_active_reset(sk, GFP_ATOMIC); + NET_INC_STATS_BH(sock_net(sk), + LINUX_MIB_TCPABORTONLINGER); + } else { + const int tmo = tcp_fin_time(sk); + + if (tmo > TCP_TIMEWAIT_LEN) { + inet_csk_reset_keepalive_timer(sk, + tmo - TCP_TIMEWAIT_LEN); + } else { + tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); + goto out; + } + } + } + if (sk->sk_state != TCP_CLOSE) { + sk_mem_reclaim(sk); + if (tcp_too_many_orphans(sk, 0)) { + if (net_ratelimit()) + printk(KERN_INFO "TCP: too many of orphaned " + "sockets\n"); + tcp_set_state(sk, TCP_CLOSE); + tcp_send_active_reset(sk, GFP_ATOMIC); + NET_INC_STATS_BH(sock_net(sk), + LINUX_MIB_TCPABORTONMEMORY); + } + } + + if (sk->sk_state == TCP_CLOSE) + inet_csk_destroy_sock(sk); + /* Otherwise, socket is reprieved until protocol close. */ + +out: + bh_unlock_sock(sk); + local_bh_enable(); + sock_put(sk); +} +EXPORT_SYMBOL(tcp_close); + +/* These states need RST on ABORT according to RFC793 */ + +static inline int tcp_need_reset(int state) +{ + return (1 << state) & + (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | + TCPF_FIN_WAIT2 | TCPF_SYN_RECV); +} + +int tcp_disconnect(struct sock *sk, int flags) +{ + struct inet_sock *inet = inet_sk(sk); + struct inet_connection_sock *icsk = inet_csk(sk); + struct tcp_sock *tp = tcp_sk(sk); + int err = 0; + int old_state = sk->sk_state; + + if (old_state != TCP_CLOSE) + tcp_set_state(sk, TCP_CLOSE); + + /* ABORT function of RFC793 */ + if (old_state == TCP_LISTEN) { + inet_csk_listen_stop(sk); + } else if (tcp_need_reset(old_state) || + (tp->snd_nxt != tp->write_seq && + (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { + /* The last check adjusts for discrepancy of Linux wrt. RFC + * states + */ + tcp_send_active_reset(sk, gfp_any()); + sk->sk_err = ECONNRESET; + } else if (old_state == TCP_SYN_SENT) + sk->sk_err = ECONNRESET; + + tcp_clear_xmit_timers(sk); + __skb_queue_purge(&sk->sk_receive_queue); + tcp_write_queue_purge(sk); + __skb_queue_purge(&tp->out_of_order_queue); +#ifdef CONFIG_NET_DMA + __skb_queue_purge(&sk->sk_async_wait_queue); +#endif + + inet->inet_dport = 0; + + if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) + inet_reset_saddr(sk); + + sk->sk_shutdown = 0; + sock_reset_flag(sk, SOCK_DONE); + tp->srtt = 0; + if ((tp->write_seq += tp->max_window + 2) == 0) + tp->write_seq = 1; + icsk->icsk_backoff = 0; + tp->snd_cwnd = 2; + icsk->icsk_probes_out = 0; + tp->packets_out = 0; + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; + tp->snd_cwnd_cnt = 0; + tp->bytes_acked = 0; + tp->window_clamp = 0; + tcp_set_ca_state(sk, TCP_CA_Open); + tcp_clear_retrans(tp); + inet_csk_delack_init(sk); + tcp_init_send_head(sk); + memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); + __sk_dst_reset(sk); + + WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); + + sk->sk_error_report(sk); + return err; +} +EXPORT_SYMBOL(tcp_disconnect); + +/* + * Socket option code for TCP. + */ +static int do_tcp_setsockopt(struct sock *sk, int level, + int optname, char __user *optval, unsigned int optlen) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct inet_connection_sock *icsk = inet_csk(sk); + int val; + int err = 0; + + /* These are data/string values, all the others are ints */ + switch (optname) { + case TCP_CONGESTION: { + char name[TCP_CA_NAME_MAX]; + + if (optlen < 1) + return -EINVAL; + + val = strncpy_from_user(name, optval, + min_t(long, TCP_CA_NAME_MAX-1, optlen)); + if (val < 0) + return -EFAULT; + name[val] = 0; + + lock_sock(sk); + err = tcp_set_congestion_control(sk, name); + release_sock(sk); + return err; + } + case TCP_COOKIE_TRANSACTIONS: { + struct tcp_cookie_transactions ctd; + struct tcp_cookie_values *cvp = NULL; + + if (sizeof(ctd) > optlen) + return -EINVAL; + if (copy_from_user(&ctd, optval, sizeof(ctd))) + return -EFAULT; + + if (ctd.tcpct_used > sizeof(ctd.tcpct_value) || + ctd.tcpct_s_data_desired > TCP_MSS_DESIRED) + return -EINVAL; + + if (ctd.tcpct_cookie_desired == 0) { + /* default to global value */ + } else if ((0x1 & ctd.tcpct_cookie_desired) || + ctd.tcpct_cookie_desired > TCP_COOKIE_MAX || + ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) { + return -EINVAL; + } + + if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) { + /* Supercedes all other values */ + lock_sock(sk); + if (tp->cookie_values != NULL) { + kref_put(&tp->cookie_values->kref, + tcp_cookie_values_release); + tp->cookie_values = NULL; + } + tp->rx_opt.cookie_in_always = 0; /* false */ + tp->rx_opt.cookie_out_never = 1; /* true */ + release_sock(sk); + return err; + } + + /* Allocate ancillary memory before locking. + */ + if (ctd.tcpct_used > 0 || + (tp->cookie_values == NULL && + (sysctl_tcp_cookie_size > 0 || + ctd.tcpct_cookie_desired > 0 || + ctd.tcpct_s_data_desired > 0))) { + cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used, + GFP_KERNEL); + if (cvp == NULL) + return -ENOMEM; + + kref_init(&cvp->kref); + } + lock_sock(sk); + tp->rx_opt.cookie_in_always = + (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags); + tp->rx_opt.cookie_out_never = 0; /* false */ + + if (tp->cookie_values != NULL) { + if (cvp != NULL) { + /* Changed values are recorded by a changed + * pointer, ensuring the cookie will differ, + * without separately hashing each value later. + */ + kref_put(&tp->cookie_values->kref, + tcp_cookie_values_release); + } else { + cvp = tp->cookie_values; + } + } + + if (cvp != NULL) { + cvp->cookie_desired = ctd.tcpct_cookie_desired; + + if (ctd.tcpct_used > 0) { + memcpy(cvp->s_data_payload, ctd.tcpct_value, + ctd.tcpct_used); + cvp->s_data_desired = ctd.tcpct_used; + cvp->s_data_constant = 1; /* true */ + } else { + /* No constant payload data. */ + cvp->s_data_desired = ctd.tcpct_s_data_desired; + cvp->s_data_constant = 0; /* false */ + } + + tp->cookie_values = cvp; + } + release_sock(sk); + return err; + } + default: + /* fallthru */ + break; + } + + if (optlen < sizeof(int)) + return -EINVAL; + + if (get_user(val, (int __user *)optval)) + return -EFAULT; + + lock_sock(sk); + + switch (optname) { + case TCP_MAXSEG: + /* Values greater than interface MTU won't take effect. However + * at the point when this call is done we typically don't yet + * know which interface is going to be used */ + if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { + err = -EINVAL; + break; + } + tp->rx_opt.user_mss = val; + break; + + case TCP_NODELAY: + if (val) { + /* TCP_NODELAY is weaker than TCP_CORK, so that + * this option on corked socket is remembered, but + * it is not activated until cork is cleared. + * + * However, when TCP_NODELAY is set we make + * an explicit push, which overrides even TCP_CORK + * for currently queued segments. + */ + tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; + tcp_push_pending_frames(sk); + } else { + tp->nonagle &= ~TCP_NAGLE_OFF; + } + break; + + case TCP_THIN_LINEAR_TIMEOUTS: + if (val < 0 || val > 1) + err = -EINVAL; + else + tp->thin_lto = val; + break; + + case TCP_THIN_DUPACK: + if (val < 0 || val > 1) + err = -EINVAL; + else + tp->thin_dupack = val; + break; + + case TCP_CORK: + /* When set indicates to always queue non-full frames. + * Later the user clears this option and we transmit + * any pending partial frames in the queue. This is + * meant to be used alongside sendfile() to get properly + * filled frames when the user (for example) must write + * out headers with a write() call first and then use + * sendfile to send out the data parts. + * + * TCP_CORK can be set together with TCP_NODELAY and it is + * stronger than TCP_NODELAY. + */ + if (val) { + tp->nonagle |= TCP_NAGLE_CORK; + } else { + tp->nonagle &= ~TCP_NAGLE_CORK; + if (tp->nonagle&TCP_NAGLE_OFF) + tp->nonagle |= TCP_NAGLE_PUSH; + tcp_push_pending_frames(sk); + } + break; + + case TCP_KEEPIDLE: + if (val < 1 || val > MAX_TCP_KEEPIDLE) + err = -EINVAL; + else { + tp->keepalive_time = val * HZ; + if (sock_flag(sk, SOCK_KEEPOPEN) && + !((1 << sk->sk_state) & + (TCPF_CLOSE | TCPF_LISTEN))) { + u32 elapsed = keepalive_time_elapsed(tp); + if (tp->keepalive_time > elapsed) + elapsed = tp->keepalive_time - elapsed; + else + elapsed = 0; + inet_csk_reset_keepalive_timer(sk, elapsed); + } + } + break; + case TCP_KEEPINTVL: + if (val < 1 || val > MAX_TCP_KEEPINTVL) + err = -EINVAL; + else + tp->keepalive_intvl = val * HZ; + break; + case TCP_KEEPCNT: + if (val < 1 || val > MAX_TCP_KEEPCNT) + err = -EINVAL; + else + tp->keepalive_probes = val; + break; + case TCP_SYNCNT: + if (val < 1 || val > MAX_TCP_SYNCNT) + err = -EINVAL; + else + icsk->icsk_syn_retries = val; + break; + + case TCP_LINGER2: + if (val < 0) + tp->linger2 = -1; + else if (val > sysctl_tcp_fin_timeout / HZ) + tp->linger2 = 0; + else + tp->linger2 = val * HZ; + break; + + case TCP_DEFER_ACCEPT: + /* Translate value in seconds to number of retransmits */ + icsk->icsk_accept_queue.rskq_defer_accept = + secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, + TCP_RTO_MAX / HZ); + break; + + case TCP_WINDOW_CLAMP: + if (!val) { + if (sk->sk_state != TCP_CLOSE) { + err = -EINVAL; + break; + } + tp->window_clamp = 0; + } else + tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? + SOCK_MIN_RCVBUF / 2 : val; + break; + + case TCP_QUICKACK: + if (!val) { + icsk->icsk_ack.pingpong = 1; + } else { + icsk->icsk_ack.pingpong = 0; + if ((1 << sk->sk_state) & + (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && + inet_csk_ack_scheduled(sk)) { + icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; + tcp_cleanup_rbuf(sk, 1); + if (!(val & 1)) + icsk->icsk_ack.pingpong = 1; + } + } + break; + +#ifdef CONFIG_TCP_MD5SIG + case TCP_MD5SIG: + /* Read the IP->Key mappings from userspace */ + err = tp->af_specific->md5_parse(sk, optval, optlen); + break; +#endif + case TCP_USER_TIMEOUT: + /* Cap the max timeout in ms TCP will retry/retrans + * before giving up and aborting (ETIMEDOUT) a connection. + */ + icsk->icsk_user_timeout = msecs_to_jiffies(val); + break; + default: + err = -ENOPROTOOPT; + break; + } + + release_sock(sk); + return err; +} + +int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, + unsigned int optlen) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + if (level != SOL_TCP) + return icsk->icsk_af_ops->setsockopt(sk, level, optname, + optval, optlen); + return do_tcp_setsockopt(sk, level, optname, optval, optlen); +} +EXPORT_SYMBOL(tcp_setsockopt); + +#ifdef CONFIG_COMPAT +int compat_tcp_setsockopt(struct sock *sk, int level, int optname, + char __user *optval, unsigned int optlen) +{ + if (level != SOL_TCP) + return inet_csk_compat_setsockopt(sk, level, optname, + optval, optlen); + return do_tcp_setsockopt(sk, level, optname, optval, optlen); +} +EXPORT_SYMBOL(compat_tcp_setsockopt); +#endif + +/* Return information about state of tcp endpoint in API format. */ +void tcp_get_info(struct sock *sk, struct tcp_info *info) +{ + struct tcp_sock *tp = tcp_sk(sk); + const struct inet_connection_sock *icsk = inet_csk(sk); + u32 now = tcp_time_stamp; + + memset(info, 0, sizeof(*info)); + + info->tcpi_state = sk->sk_state; + info->tcpi_ca_state = icsk->icsk_ca_state; + info->tcpi_retransmits = icsk->icsk_retransmits; + info->tcpi_probes = icsk->icsk_probes_out; + info->tcpi_backoff = icsk->icsk_backoff; + + if (tp->rx_opt.tstamp_ok) + info->tcpi_options |= TCPI_OPT_TIMESTAMPS; + if (tcp_is_sack(tp)) + info->tcpi_options |= TCPI_OPT_SACK; + if (tp->rx_opt.wscale_ok) { + info->tcpi_options |= TCPI_OPT_WSCALE; + info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; + info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; + } + + if (tp->ecn_flags&TCP_ECN_OK) + info->tcpi_options |= TCPI_OPT_ECN; + + info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); + info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); + info->tcpi_snd_mss = tp->mss_cache; + info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; + + if (sk->sk_state == TCP_LISTEN) { + info->tcpi_unacked = sk->sk_ack_backlog; + info->tcpi_sacked = sk->sk_max_ack_backlog; + } else { + info->tcpi_unacked = tp->packets_out; + info->tcpi_sacked = tp->sacked_out; + } + info->tcpi_lost = tp->lost_out; + info->tcpi_retrans = tp->retrans_out; + info->tcpi_fackets = tp->fackets_out; + + info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); + info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); + info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); + + info->tcpi_pmtu = icsk->icsk_pmtu_cookie; + info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; + info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; + info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; + info->tcpi_snd_ssthresh = tp->snd_ssthresh; + info->tcpi_snd_cwnd = tp->snd_cwnd; + info->tcpi_advmss = tp->advmss; + info->tcpi_reordering = tp->reordering; + + info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; + info->tcpi_rcv_space = tp->rcvq_space.space; + + info->tcpi_total_retrans = tp->total_retrans; +} +EXPORT_SYMBOL_GPL(tcp_get_info); + +static int do_tcp_getsockopt(struct sock *sk, int level, + int optname, char __user *optval, int __user *optlen) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + struct tcp_sock *tp = tcp_sk(sk); + int val, len; + + if (get_user(len, optlen)) + return -EFAULT; + + len = min_t(unsigned int, len, sizeof(int)); + + if (len < 0) + return -EINVAL; + + switch (optname) { + case TCP_MAXSEG: + val = tp->mss_cache; + if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) + val = tp->rx_opt.user_mss; + break; + case TCP_NODELAY: + val = !!(tp->nonagle&TCP_NAGLE_OFF); + break; + case TCP_CORK: + val = !!(tp->nonagle&TCP_NAGLE_CORK); + break; + case TCP_KEEPIDLE: + val = keepalive_time_when(tp) / HZ; + break; + case TCP_KEEPINTVL: + val = keepalive_intvl_when(tp) / HZ; + break; + case TCP_KEEPCNT: + val = keepalive_probes(tp); + break; + case TCP_SYNCNT: + val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; + break; + case TCP_LINGER2: + val = tp->linger2; + if (val >= 0) + val = (val ? : sysctl_tcp_fin_timeout) / HZ; + break; + case TCP_DEFER_ACCEPT: + val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, + TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); + break; + case TCP_WINDOW_CLAMP: + val = tp->window_clamp; + break; + case TCP_INFO: { + struct tcp_info info; + + if (get_user(len, optlen)) + return -EFAULT; + + tcp_get_info(sk, &info); + + len = min_t(unsigned int, len, sizeof(info)); + if (put_user(len, optlen)) + return -EFAULT; + if (copy_to_user(optval, &info, len)) + return -EFAULT; + return 0; + } + case TCP_QUICKACK: + val = !icsk->icsk_ack.pingpong; + break; + + case TCP_CONGESTION: + if (get_user(len, optlen)) + return -EFAULT; + len = min_t(unsigned int, len, TCP_CA_NAME_MAX); + if (put_user(len, optlen)) + return -EFAULT; + if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) + return -EFAULT; + return 0; + + case TCP_COOKIE_TRANSACTIONS: { + struct tcp_cookie_transactions ctd; + struct tcp_cookie_values *cvp = tp->cookie_values; + + if (get_user(len, optlen)) + return -EFAULT; + if (len < sizeof(ctd)) + return -EINVAL; + + memset(&ctd, 0, sizeof(ctd)); + ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ? + TCP_COOKIE_IN_ALWAYS : 0) + | (tp->rx_opt.cookie_out_never ? + TCP_COOKIE_OUT_NEVER : 0); + + if (cvp != NULL) { + ctd.tcpct_flags |= (cvp->s_data_in ? + TCP_S_DATA_IN : 0) + | (cvp->s_data_out ? + TCP_S_DATA_OUT : 0); + + ctd.tcpct_cookie_desired = cvp->cookie_desired; + ctd.tcpct_s_data_desired = cvp->s_data_desired; + + memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0], + cvp->cookie_pair_size); + ctd.tcpct_used = cvp->cookie_pair_size; + } + + if (put_user(sizeof(ctd), optlen)) + return -EFAULT; + if (copy_to_user(optval, &ctd, sizeof(ctd))) + return -EFAULT; + return 0; + } + case TCP_THIN_LINEAR_TIMEOUTS: + val = tp->thin_lto; + break; + case TCP_THIN_DUPACK: + val = tp->thin_dupack; + break; + + case TCP_USER_TIMEOUT: + val = jiffies_to_msecs(icsk->icsk_user_timeout); + break; + default: + return -ENOPROTOOPT; + } + + if (put_user(len, optlen)) + return -EFAULT; + if (copy_to_user(optval, &val, len)) + return -EFAULT; + return 0; +} + +int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, + int __user *optlen) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + if (level != SOL_TCP) + return icsk->icsk_af_ops->getsockopt(sk, level, optname, + optval, optlen); + return do_tcp_getsockopt(sk, level, optname, optval, optlen); +} +EXPORT_SYMBOL(tcp_getsockopt); + +#ifdef CONFIG_COMPAT +int compat_tcp_getsockopt(struct sock *sk, int level, int optname, + char __user *optval, int __user *optlen) +{ + if (level != SOL_TCP) + return inet_csk_compat_getsockopt(sk, level, optname, + optval, optlen); + return do_tcp_getsockopt(sk, level, optname, optval, optlen); +} +EXPORT_SYMBOL(compat_tcp_getsockopt); +#endif + +struct sk_buff *tcp_tso_segment(struct sk_buff *skb, u32 features) +{ + struct sk_buff *segs = ERR_PTR(-EINVAL); + struct tcphdr *th; + unsigned thlen; + unsigned int seq; + __be32 delta; + unsigned int oldlen; + unsigned int mss; + + if (!pskb_may_pull(skb, sizeof(*th))) + goto out; + + th = tcp_hdr(skb); + thlen = th->doff * 4; + if (thlen < sizeof(*th)) + goto out; + + if (!pskb_may_pull(skb, thlen)) + goto out; + + oldlen = (u16)~skb->len; + __skb_pull(skb, thlen); + + mss = skb_shinfo(skb)->gso_size; + if (unlikely(skb->len <= mss)) + goto out; + + if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { + /* Packet is from an untrusted source, reset gso_segs. */ + int type = skb_shinfo(skb)->gso_type; + + if (unlikely(type & + ~(SKB_GSO_TCPV4 | + SKB_GSO_DODGY | + SKB_GSO_TCP_ECN | + SKB_GSO_TCPV6 | + 0) || + !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) + goto out; + + skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); + + segs = NULL; + goto out; + } + + segs = skb_segment(skb, features); + if (IS_ERR(segs)) + goto out; + + delta = htonl(oldlen + (thlen + mss)); + + skb = segs; + th = tcp_hdr(skb); + seq = ntohl(th->seq); + + do { + th->fin = th->psh = 0; + + th->check = ~csum_fold((__force __wsum)((__force u32)th->check + + (__force u32)delta)); + if (skb->ip_summed != CHECKSUM_PARTIAL) + th->check = + csum_fold(csum_partial(skb_transport_header(skb), + thlen, skb->csum)); + + seq += mss; + skb = skb->next; + th = tcp_hdr(skb); + + th->seq = htonl(seq); + th->cwr = 0; + } while (skb->next); + + delta = htonl(oldlen + (skb->tail - skb->transport_header) + + skb->data_len); + th->check = ~csum_fold((__force __wsum)((__force u32)th->check + + (__force u32)delta)); + if (skb->ip_summed != CHECKSUM_PARTIAL) + th->check = csum_fold(csum_partial(skb_transport_header(skb), + thlen, skb->csum)); + +out: + return segs; +} +EXPORT_SYMBOL(tcp_tso_segment); + +struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + struct sk_buff **pp = NULL; + struct sk_buff *p; + struct tcphdr *th; + struct tcphdr *th2; + unsigned int len; + unsigned int thlen; + __be32 flags; + unsigned int mss = 1; + unsigned int hlen; + unsigned int off; + int flush = 1; + int i; + + off = skb_gro_offset(skb); + hlen = off + sizeof(*th); + th = skb_gro_header_fast(skb, off); + if (skb_gro_header_hard(skb, hlen)) { + th = skb_gro_header_slow(skb, hlen, off); + if (unlikely(!th)) + goto out; + } + + thlen = th->doff * 4; + if (thlen < sizeof(*th)) + goto out; + + hlen = off + thlen; + if (skb_gro_header_hard(skb, hlen)) { + th = skb_gro_header_slow(skb, hlen, off); + if (unlikely(!th)) + goto out; + } + + skb_gro_pull(skb, thlen); + + len = skb_gro_len(skb); + flags = tcp_flag_word(th); + + for (; (p = *head); head = &p->next) { + if (!NAPI_GRO_CB(p)->same_flow) + continue; + + th2 = tcp_hdr(p); + + if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + + goto found; + } + + goto out_check_final; + +found: + flush = NAPI_GRO_CB(p)->flush; + flush |= (__force int)(flags & TCP_FLAG_CWR); + flush |= (__force int)((flags ^ tcp_flag_word(th2)) & + ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); + flush |= (__force int)(th->ack_seq ^ th2->ack_seq); + for (i = sizeof(*th); i < thlen; i += 4) + flush |= *(u32 *)((u8 *)th + i) ^ + *(u32 *)((u8 *)th2 + i); + + mss = skb_shinfo(p)->gso_size; + + flush |= (len - 1) >= mss; + flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); + + if (flush || skb_gro_receive(head, skb)) { + mss = 1; + goto out_check_final; + } + + p = *head; + th2 = tcp_hdr(p); + tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); + +out_check_final: + flush = len < mss; + flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | + TCP_FLAG_RST | TCP_FLAG_SYN | + TCP_FLAG_FIN)); + + if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) + pp = head; + +out: + NAPI_GRO_CB(skb)->flush |= flush; + + return pp; +} +EXPORT_SYMBOL(tcp_gro_receive); + +int tcp_gro_complete(struct sk_buff *skb) +{ + struct tcphdr *th = tcp_hdr(skb); + + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = offsetof(struct tcphdr, check); + skb->ip_summed = CHECKSUM_PARTIAL; + + skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; + + if (th->cwr) + skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; + + return 0; +} +EXPORT_SYMBOL(tcp_gro_complete); + +#ifdef CONFIG_TCP_MD5SIG +static unsigned long tcp_md5sig_users; +static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool; +static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); + +static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool) +{ + int cpu; + for_each_possible_cpu(cpu) { + struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); + if (p) { + if (p->md5_desc.tfm) + crypto_free_hash(p->md5_desc.tfm); + kfree(p); + } + } + free_percpu(pool); +} + +void tcp_free_md5sig_pool(void) +{ + struct tcp_md5sig_pool * __percpu *pool = NULL; + + spin_lock_bh(&tcp_md5sig_pool_lock); + if (--tcp_md5sig_users == 0) { + pool = tcp_md5sig_pool; + tcp_md5sig_pool = NULL; + } + spin_unlock_bh(&tcp_md5sig_pool_lock); + if (pool) + __tcp_free_md5sig_pool(pool); +} +EXPORT_SYMBOL(tcp_free_md5sig_pool); + +static struct tcp_md5sig_pool * __percpu * +__tcp_alloc_md5sig_pool(struct sock *sk) +{ + int cpu; + struct tcp_md5sig_pool * __percpu *pool; + + pool = alloc_percpu(struct tcp_md5sig_pool *); + if (!pool) + return NULL; + + for_each_possible_cpu(cpu) { + struct tcp_md5sig_pool *p; + struct crypto_hash *hash; + + p = kzalloc(sizeof(*p), sk->sk_allocation); + if (!p) + goto out_free; + *per_cpu_ptr(pool, cpu) = p; + + hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); + if (!hash || IS_ERR(hash)) + goto out_free; + + p->md5_desc.tfm = hash; + } + return pool; +out_free: + __tcp_free_md5sig_pool(pool); + return NULL; +} + +struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk) +{ + struct tcp_md5sig_pool * __percpu *pool; + int alloc = 0; + +retry: + spin_lock_bh(&tcp_md5sig_pool_lock); + pool = tcp_md5sig_pool; + if (tcp_md5sig_users++ == 0) { + alloc = 1; + spin_unlock_bh(&tcp_md5sig_pool_lock); + } else if (!pool) { + tcp_md5sig_users--; + spin_unlock_bh(&tcp_md5sig_pool_lock); + cpu_relax(); + goto retry; + } else + spin_unlock_bh(&tcp_md5sig_pool_lock); + + if (alloc) { + /* we cannot hold spinlock here because this may sleep. */ + struct tcp_md5sig_pool * __percpu *p; + + p = __tcp_alloc_md5sig_pool(sk); + spin_lock_bh(&tcp_md5sig_pool_lock); + if (!p) { + tcp_md5sig_users--; + spin_unlock_bh(&tcp_md5sig_pool_lock); + return NULL; + } + pool = tcp_md5sig_pool; + if (pool) { + /* oops, it has already been assigned. */ + spin_unlock_bh(&tcp_md5sig_pool_lock); + __tcp_free_md5sig_pool(p); + } else { + tcp_md5sig_pool = pool = p; + spin_unlock_bh(&tcp_md5sig_pool_lock); + } + } + return pool; +} +EXPORT_SYMBOL(tcp_alloc_md5sig_pool); + + +/** + * 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) +{ + struct tcp_md5sig_pool * __percpu *p; + + local_bh_disable(); + + spin_lock(&tcp_md5sig_pool_lock); + p = tcp_md5sig_pool; + if (p) + tcp_md5sig_users++; + spin_unlock(&tcp_md5sig_pool_lock); + + if (p) + return *this_cpu_ptr(p); + + local_bh_enable(); + return NULL; +} +EXPORT_SYMBOL(tcp_get_md5sig_pool); + +void tcp_put_md5sig_pool(void) +{ + local_bh_enable(); + tcp_free_md5sig_pool(); +} +EXPORT_SYMBOL(tcp_put_md5sig_pool); + +int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, + struct tcphdr *th) +{ + struct scatterlist sg; + int err; + + __sum16 old_checksum = th->check; + th->check = 0; + /* options aren't included in the hash */ + sg_init_one(&sg, th, sizeof(struct tcphdr)); + err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr)); + th->check = old_checksum; + return err; +} +EXPORT_SYMBOL(tcp_md5_hash_header); + +int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, + struct sk_buff *skb, unsigned header_len) +{ + struct scatterlist sg; + const struct tcphdr *tp = tcp_hdr(skb); + struct hash_desc *desc = &hp->md5_desc; + unsigned i; + const unsigned head_data_len = skb_headlen(skb) > header_len ? + skb_headlen(skb) - header_len : 0; + const struct skb_shared_info *shi = skb_shinfo(skb); + struct sk_buff *frag_iter; + + sg_init_table(&sg, 1); + + sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); + if (crypto_hash_update(desc, &sg, head_data_len)) + return 1; + + for (i = 0; i < shi->nr_frags; ++i) { + const struct skb_frag_struct *f = &shi->frags[i]; + sg_set_page(&sg, f->page, f->size, f->page_offset); + if (crypto_hash_update(desc, &sg, f->size)) + 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, struct tcp_md5sig_key *key) +{ + struct scatterlist sg; + + sg_init_one(&sg, key->key, key->keylen); + return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); +} +EXPORT_SYMBOL(tcp_md5_hash_key); + +#endif + +/** + * Each Responder maintains up to two secret values concurrently for + * efficient secret rollover. Each secret value has 4 states: + * + * Generating. (tcp_secret_generating != tcp_secret_primary) + * Generates new Responder-Cookies, but not yet used for primary + * verification. This is a short-term state, typically lasting only + * one round trip time (RTT). + * + * Primary. (tcp_secret_generating == tcp_secret_primary) + * Used both for generation and primary verification. + * + * Retiring. (tcp_secret_retiring != tcp_secret_secondary) + * Used for verification, until the first failure that can be + * verified by the newer Generating secret. At that time, this + * cookie's state is changed to Secondary, and the Generating + * cookie's state is changed to Primary. This is a short-term state, + * typically lasting only one round trip time (RTT). + * + * Secondary. (tcp_secret_retiring == tcp_secret_secondary) + * Used for secondary verification, after primary verification + * failures. This state lasts no more than twice the Maximum Segment + * Lifetime (2MSL). Then, the secret is discarded. + */ +struct tcp_cookie_secret { + /* The secret is divided into two parts. The digest part is the + * equivalent of previously hashing a secret and saving the state, + * and serves as an initialization vector (IV). The message part + * serves as the trailing secret. + */ + u32 secrets[COOKIE_WORKSPACE_WORDS]; + unsigned long expires; +}; + +#define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL) +#define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2) +#define TCP_SECRET_LIFE (HZ * 600) + +static struct tcp_cookie_secret tcp_secret_one; +static struct tcp_cookie_secret tcp_secret_two; + +/* Essentially a circular list, without dynamic allocation. */ +static struct tcp_cookie_secret *tcp_secret_generating; +static struct tcp_cookie_secret *tcp_secret_primary; +static struct tcp_cookie_secret *tcp_secret_retiring; +static struct tcp_cookie_secret *tcp_secret_secondary; + +static DEFINE_SPINLOCK(tcp_secret_locker); + +/* Select a pseudo-random word in the cookie workspace. + */ +static inline u32 tcp_cookie_work(const u32 *ws, const int n) +{ + return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])]; +} + +/* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed. + * Called in softirq context. + * Returns: 0 for success. + */ +int tcp_cookie_generator(u32 *bakery) +{ + unsigned long jiffy = jiffies; + + if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) { + spin_lock_bh(&tcp_secret_locker); + if (!time_after_eq(jiffy, tcp_secret_generating->expires)) { + /* refreshed by another */ + memcpy(bakery, + &tcp_secret_generating->secrets[0], + COOKIE_WORKSPACE_WORDS); + } else { + /* still needs refreshing */ + get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS); + + /* The first time, paranoia assumes that the + * randomization function isn't as strong. But, + * this secret initialization is delayed until + * the last possible moment (packet arrival). + * Although that time is observable, it is + * unpredictably variable. Mash in the most + * volatile clock bits available, and expire the + * secret extra quickly. + */ + if (unlikely(tcp_secret_primary->expires == + tcp_secret_secondary->expires)) { + struct timespec tv; + + getnstimeofday(&tv); + bakery[COOKIE_DIGEST_WORDS+0] ^= + (u32)tv.tv_nsec; + + tcp_secret_secondary->expires = jiffy + + TCP_SECRET_1MSL + + (0x0f & tcp_cookie_work(bakery, 0)); + } else { + tcp_secret_secondary->expires = jiffy + + TCP_SECRET_LIFE + + (0xff & tcp_cookie_work(bakery, 1)); + tcp_secret_primary->expires = jiffy + + TCP_SECRET_2MSL + + (0x1f & tcp_cookie_work(bakery, 2)); + } + memcpy(&tcp_secret_secondary->secrets[0], + bakery, COOKIE_WORKSPACE_WORDS); + + rcu_assign_pointer(tcp_secret_generating, + tcp_secret_secondary); + rcu_assign_pointer(tcp_secret_retiring, + tcp_secret_primary); + /* + * Neither call_rcu() nor synchronize_rcu() needed. + * Retiring data is not freed. It is replaced after + * further (locked) pointer updates, and a quiet time + * (minimum 1MSL, maximum LIFE - 2MSL). + */ + } + spin_unlock_bh(&tcp_secret_locker); + } else { + rcu_read_lock_bh(); + memcpy(bakery, + &rcu_dereference(tcp_secret_generating)->secrets[0], + COOKIE_WORKSPACE_WORDS); + rcu_read_unlock_bh(); + } + return 0; +} +EXPORT_SYMBOL(tcp_cookie_generator); + +void tcp_done(struct sock *sk) +{ + if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); + + tcp_set_state(sk, TCP_CLOSE); + tcp_clear_xmit_timers(sk); + + sk->sk_shutdown = SHUTDOWN_MASK; + + if (!sock_flag(sk, SOCK_DEAD)) + sk->sk_state_change(sk); + else + inet_csk_destroy_sock(sk); +} +EXPORT_SYMBOL_GPL(tcp_done); + +extern struct tcp_congestion_ops tcp_reno; + +static __initdata unsigned long thash_entries; +static int __init set_thash_entries(char *str) +{ + if (!str) + return 0; + thash_entries = simple_strtoul(str, &str, 0); + return 1; +} +__setup("thash_entries=", set_thash_entries); + +void __init tcp_init(void) +{ + struct sk_buff *skb = NULL; + unsigned long limit; + int i, max_rshare, max_wshare, cnt; + unsigned long jiffy = jiffies; + + BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); + + percpu_counter_init(&tcp_sockets_allocated, 0); + percpu_counter_init(&tcp_orphan_count, 0); + tcp_hashinfo.bind_bucket_cachep = + kmem_cache_create("tcp_bind_bucket", + sizeof(struct inet_bind_bucket), 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); + + /* Size and allocate the main established and bind bucket + * hash tables. + * + * The methodology is similar to that of the buffer cache. + */ + tcp_hashinfo.ehash = + alloc_large_system_hash("TCP established", + sizeof(struct inet_ehash_bucket), + thash_entries, + (totalram_pages >= 128 * 1024) ? + 13 : 15, + 0, + NULL, + &tcp_hashinfo.ehash_mask, + thash_entries ? 0 : 512 * 1024); + for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) { + INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); + INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); + } + if (inet_ehash_locks_alloc(&tcp_hashinfo)) + panic("TCP: failed to alloc ehash_locks"); + tcp_hashinfo.bhash = + alloc_large_system_hash("TCP bind", + sizeof(struct inet_bind_hashbucket), + tcp_hashinfo.ehash_mask + 1, + (totalram_pages >= 128 * 1024) ? + 13 : 15, + 0, + &tcp_hashinfo.bhash_size, + NULL, + 64 * 1024); + tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; + for (i = 0; i < tcp_hashinfo.bhash_size; i++) { + spin_lock_init(&tcp_hashinfo.bhash[i].lock); + INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); + } + + + cnt = tcp_hashinfo.ehash_mask + 1; + + tcp_death_row.sysctl_max_tw_buckets = cnt / 2; + sysctl_tcp_max_orphans = cnt / 2; + sysctl_max_syn_backlog = max(128, cnt / 256); + + limit = nr_free_buffer_pages() / 8; + limit = max(limit, 128UL); + sysctl_tcp_mem[0] = limit / 4 * 3; + sysctl_tcp_mem[1] = limit; + sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; + + /* Set per-socket limits to no more than 1/128 the pressure threshold */ + limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); + max_wshare = min(4UL*1024*1024, limit); + max_rshare = min(6UL*1024*1024, limit); + + sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; + sysctl_tcp_wmem[1] = 16*1024; + sysctl_tcp_wmem[2] = max(64*1024, max_wshare); + + sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; + sysctl_tcp_rmem[1] = 87380; + sysctl_tcp_rmem[2] = max(87380, max_rshare); + + printk(KERN_INFO "TCP: Hash tables configured " + "(established %u bind %u)\n", + tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); + + tcp_register_congestion_control(&tcp_reno); + + memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets)); + memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets)); + tcp_secret_one.expires = jiffy; /* past due */ + tcp_secret_two.expires = jiffy; /* past due */ + tcp_secret_generating = &tcp_secret_one; + tcp_secret_primary = &tcp_secret_one; + tcp_secret_retiring = &tcp_secret_two; + tcp_secret_secondary = &tcp_secret_two; +} + +static int tcp_is_local(struct net *net, __be32 addr) { + struct rtable *rt; + struct flowi4 fl4 = { .daddr = addr }; + rt = ip_route_output_key(net, &fl4); + if (IS_ERR_OR_NULL(rt)) + return 0; + return rt->dst.dev && (rt->dst.dev->flags & IFF_LOOPBACK); +} + +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) +static int tcp_is_local6(struct net *net, struct in6_addr *addr) { + struct rt6_info *rt6 = rt6_lookup(net, addr, addr, 0, 0); + return rt6 && rt6->rt6i_dev && (rt6->rt6i_dev->flags & IFF_LOOPBACK); +} +#endif + +/* + * tcp_nuke_addr - destroy all sockets on the given local address + * if local address is the unspecified address (0.0.0.0 or ::), destroy all + * sockets with local addresses that are not configured. + */ +int tcp_nuke_addr(struct net *net, struct sockaddr *addr) +{ + int family = addr->sa_family; + unsigned int bucket; + + struct in_addr *in; +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) + struct in6_addr *in6 = NULL; +#endif + if (family == AF_INET) { + in = &((struct sockaddr_in *)addr)->sin_addr; +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) + } else if (family == AF_INET6) { + in6 = &((struct sockaddr_in6 *)addr)->sin6_addr; +#endif + } else { + return -EAFNOSUPPORT; + } + + for (bucket = 0; bucket < tcp_hashinfo.ehash_mask; bucket++) { + struct hlist_nulls_node *node; + struct sock *sk; + spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, bucket); + +restart: + spin_lock_bh(lock); + sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[bucket].chain) { + struct inet_sock *inet = inet_sk(sk); + + if (sysctl_ip_dynaddr && sk->sk_state == TCP_SYN_SENT) + continue; + if (sock_flag(sk, SOCK_DEAD)) + continue; + + if (family == AF_INET) { + __be32 s4 = inet->inet_rcv_saddr; + if (s4 == LOOPBACK4_IPV6) + continue; + + if (in->s_addr != s4 && + !(in->s_addr == INADDR_ANY && + !tcp_is_local(net, s4))) + continue; + } + +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) + if (family == AF_INET6) { + struct in6_addr *s6; + if (!inet->pinet6) + continue; + + s6 = &inet->pinet6->rcv_saddr; + if (ipv6_addr_type(s6) == IPV6_ADDR_MAPPED) + continue; + + if (!ipv6_addr_equal(in6, s6) && + !(ipv6_addr_equal(in6, &in6addr_any) && + !tcp_is_local6(net, s6))) + continue; + } +#endif + + sock_hold(sk); + spin_unlock_bh(lock); + + local_bh_disable(); + bh_lock_sock(sk); + sk->sk_err = ETIMEDOUT; + sk->sk_error_report(sk); + + tcp_done(sk); + bh_unlock_sock(sk); + local_bh_enable(); + sock_put(sk); + + goto restart; + } + spin_unlock_bh(lock); + } + + return 0; +} |