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10d3be5692
Linux TCP stack painfully segments all TSO/GSO packets before retransmits. This was fine back in the days when TSO/GSO were emerging, with their bugs, but we believe the dark age is over. Keeping big packets in write queues, but also in stack traversal has a lot of benefits. - Less memory overhead, because write queues have less skbs - Less cpu overhead at ACK processing. - Better SACK processing, as lot of studies mentioned how awful linux was at this ;) - Less cpu overhead to send the rtx packets (IP stack traversal, netfilter traversal, drivers...) - Better latencies in presence of losses. - Smaller spikes in fq like packet schedulers, as retransmits are not constrained by TCP Small Queues. 1 % packet losses are common today, and at 100Gbit speeds, this translates to ~80,000 losses per second. Losses are often correlated, and we see many retransmit events leading to 1-MSS train of packets, at the time hosts are already under stress. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1860 lines
55 KiB
C
1860 lines
55 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Definitions for the TCP module.
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*
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* Version: @(#)tcp.h 1.0.5 05/23/93
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _TCP_H
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#define _TCP_H
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#define FASTRETRANS_DEBUG 1
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#include <linux/list.h>
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#include <linux/tcp.h>
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#include <linux/bug.h>
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#include <linux/slab.h>
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#include <linux/cache.h>
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#include <linux/percpu.h>
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#include <linux/skbuff.h>
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#include <linux/cryptohash.h>
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#include <linux/kref.h>
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#include <linux/ktime.h>
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#include <net/inet_connection_sock.h>
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#include <net/inet_timewait_sock.h>
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#include <net/inet_hashtables.h>
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#include <net/checksum.h>
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#include <net/request_sock.h>
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#include <net/sock.h>
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#include <net/snmp.h>
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#include <net/ip.h>
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#include <net/tcp_states.h>
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#include <net/inet_ecn.h>
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#include <net/dst.h>
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#include <linux/seq_file.h>
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#include <linux/memcontrol.h>
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extern struct inet_hashinfo tcp_hashinfo;
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extern struct percpu_counter tcp_orphan_count;
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void tcp_time_wait(struct sock *sk, int state, int timeo);
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#define MAX_TCP_HEADER (128 + MAX_HEADER)
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#define MAX_TCP_OPTION_SPACE 40
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/*
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* Never offer a window over 32767 without using window scaling. Some
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* poor stacks do signed 16bit maths!
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*/
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#define MAX_TCP_WINDOW 32767U
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/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
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#define TCP_MIN_MSS 88U
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/* The least MTU to use for probing */
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#define TCP_BASE_MSS 1024
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/* probing interval, default to 10 minutes as per RFC4821 */
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#define TCP_PROBE_INTERVAL 600
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/* Specify interval when tcp mtu probing will stop */
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#define TCP_PROBE_THRESHOLD 8
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/* After receiving this amount of duplicate ACKs fast retransmit starts. */
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#define TCP_FASTRETRANS_THRESH 3
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/* Maximal number of ACKs sent quickly to accelerate slow-start. */
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#define TCP_MAX_QUICKACKS 16U
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/* urg_data states */
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#define TCP_URG_VALID 0x0100
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#define TCP_URG_NOTYET 0x0200
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#define TCP_URG_READ 0x0400
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#define TCP_RETR1 3 /*
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* This is how many retries it does before it
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* tries to figure out if the gateway is
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* down. Minimal RFC value is 3; it corresponds
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* to ~3sec-8min depending on RTO.
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*/
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#define TCP_RETR2 15 /*
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* This should take at least
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* 90 minutes to time out.
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* RFC1122 says that the limit is 100 sec.
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* 15 is ~13-30min depending on RTO.
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*/
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#define TCP_SYN_RETRIES 6 /* This is how many retries are done
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* when active opening a connection.
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* RFC1122 says the minimum retry MUST
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* be at least 180secs. Nevertheless
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* this value is corresponding to
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* 63secs of retransmission with the
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* current initial RTO.
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*/
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#define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
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* when passive opening a connection.
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* This is corresponding to 31secs of
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* retransmission with the current
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* initial RTO.
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*/
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#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
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* state, about 60 seconds */
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#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
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/* BSD style FIN_WAIT2 deadlock breaker.
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* It used to be 3min, new value is 60sec,
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* to combine FIN-WAIT-2 timeout with
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* TIME-WAIT timer.
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*/
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#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
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#if HZ >= 100
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#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
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#define TCP_ATO_MIN ((unsigned)(HZ/25))
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#else
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#define TCP_DELACK_MIN 4U
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#define TCP_ATO_MIN 4U
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#endif
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#define TCP_RTO_MAX ((unsigned)(120*HZ))
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#define TCP_RTO_MIN ((unsigned)(HZ/5))
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#define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
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#define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
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* used as a fallback RTO for the
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* initial data transmission if no
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* valid RTT sample has been acquired,
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* most likely due to retrans in 3WHS.
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*/
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#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
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* for local resources.
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*/
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#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
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#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
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#define TCP_KEEPALIVE_INTVL (75*HZ)
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#define MAX_TCP_KEEPIDLE 32767
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#define MAX_TCP_KEEPINTVL 32767
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#define MAX_TCP_KEEPCNT 127
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#define MAX_TCP_SYNCNT 127
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#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
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#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
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#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
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* after this time. It should be equal
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* (or greater than) TCP_TIMEWAIT_LEN
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* to provide reliability equal to one
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* provided by timewait state.
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*/
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#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
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* timestamps. It must be less than
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* minimal timewait lifetime.
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*/
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/*
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* TCP option
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*/
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#define TCPOPT_NOP 1 /* Padding */
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#define TCPOPT_EOL 0 /* End of options */
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#define TCPOPT_MSS 2 /* Segment size negotiating */
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#define TCPOPT_WINDOW 3 /* Window scaling */
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#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
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#define TCPOPT_SACK 5 /* SACK Block */
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#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
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#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
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#define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
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#define TCPOPT_EXP 254 /* Experimental */
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/* Magic number to be after the option value for sharing TCP
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* experimental options. See draft-ietf-tcpm-experimental-options-00.txt
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*/
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#define TCPOPT_FASTOPEN_MAGIC 0xF989
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/*
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* TCP option lengths
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*/
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#define TCPOLEN_MSS 4
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#define TCPOLEN_WINDOW 3
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#define TCPOLEN_SACK_PERM 2
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#define TCPOLEN_TIMESTAMP 10
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#define TCPOLEN_MD5SIG 18
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#define TCPOLEN_FASTOPEN_BASE 2
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#define TCPOLEN_EXP_FASTOPEN_BASE 4
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/* But this is what stacks really send out. */
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#define TCPOLEN_TSTAMP_ALIGNED 12
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#define TCPOLEN_WSCALE_ALIGNED 4
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#define TCPOLEN_SACKPERM_ALIGNED 4
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#define TCPOLEN_SACK_BASE 2
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#define TCPOLEN_SACK_BASE_ALIGNED 4
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#define TCPOLEN_SACK_PERBLOCK 8
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#define TCPOLEN_MD5SIG_ALIGNED 20
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#define TCPOLEN_MSS_ALIGNED 4
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/* Flags in tp->nonagle */
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#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
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#define TCP_NAGLE_CORK 2 /* Socket is corked */
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#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
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/* TCP thin-stream limits */
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#define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
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/* TCP initial congestion window as per rfc6928 */
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#define TCP_INIT_CWND 10
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/* Bit Flags for sysctl_tcp_fastopen */
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#define TFO_CLIENT_ENABLE 1
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#define TFO_SERVER_ENABLE 2
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#define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
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/* Accept SYN data w/o any cookie option */
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#define TFO_SERVER_COOKIE_NOT_REQD 0x200
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/* Force enable TFO on all listeners, i.e., not requiring the
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* TCP_FASTOPEN socket option. SOCKOPT1/2 determine how to set max_qlen.
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*/
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#define TFO_SERVER_WO_SOCKOPT1 0x400
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#define TFO_SERVER_WO_SOCKOPT2 0x800
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extern struct inet_timewait_death_row tcp_death_row;
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/* sysctl variables for tcp */
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extern int sysctl_tcp_timestamps;
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extern int sysctl_tcp_window_scaling;
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extern int sysctl_tcp_sack;
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extern int sysctl_tcp_fastopen;
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extern int sysctl_tcp_retrans_collapse;
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extern int sysctl_tcp_stdurg;
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extern int sysctl_tcp_rfc1337;
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extern int sysctl_tcp_abort_on_overflow;
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extern int sysctl_tcp_max_orphans;
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extern int sysctl_tcp_fack;
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extern int sysctl_tcp_reordering;
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extern int sysctl_tcp_max_reordering;
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extern int sysctl_tcp_dsack;
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extern long sysctl_tcp_mem[3];
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extern int sysctl_tcp_wmem[3];
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extern int sysctl_tcp_rmem[3];
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extern int sysctl_tcp_app_win;
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extern int sysctl_tcp_adv_win_scale;
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extern int sysctl_tcp_tw_reuse;
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extern int sysctl_tcp_frto;
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extern int sysctl_tcp_low_latency;
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extern int sysctl_tcp_nometrics_save;
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extern int sysctl_tcp_moderate_rcvbuf;
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extern int sysctl_tcp_tso_win_divisor;
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extern int sysctl_tcp_workaround_signed_windows;
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extern int sysctl_tcp_slow_start_after_idle;
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extern int sysctl_tcp_thin_linear_timeouts;
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extern int sysctl_tcp_thin_dupack;
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extern int sysctl_tcp_early_retrans;
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extern int sysctl_tcp_limit_output_bytes;
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extern int sysctl_tcp_challenge_ack_limit;
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extern int sysctl_tcp_min_tso_segs;
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extern int sysctl_tcp_min_rtt_wlen;
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extern int sysctl_tcp_autocorking;
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extern int sysctl_tcp_invalid_ratelimit;
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extern int sysctl_tcp_pacing_ss_ratio;
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extern int sysctl_tcp_pacing_ca_ratio;
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extern atomic_long_t tcp_memory_allocated;
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extern struct percpu_counter tcp_sockets_allocated;
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extern int tcp_memory_pressure;
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/* optimized version of sk_under_memory_pressure() for TCP sockets */
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static inline bool tcp_under_memory_pressure(const struct sock *sk)
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{
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if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
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mem_cgroup_under_socket_pressure(sk->sk_memcg))
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return true;
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return tcp_memory_pressure;
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}
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/*
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* The next routines deal with comparing 32 bit unsigned ints
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* and worry about wraparound (automatic with unsigned arithmetic).
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*/
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static inline bool before(__u32 seq1, __u32 seq2)
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{
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return (__s32)(seq1-seq2) < 0;
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}
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#define after(seq2, seq1) before(seq1, seq2)
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/* is s2<=s1<=s3 ? */
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static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3)
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{
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return seq3 - seq2 >= seq1 - seq2;
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}
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static inline bool tcp_out_of_memory(struct sock *sk)
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{
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if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
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sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
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return true;
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return false;
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}
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void sk_forced_mem_schedule(struct sock *sk, int size);
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static inline bool tcp_too_many_orphans(struct sock *sk, int shift)
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{
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struct percpu_counter *ocp = sk->sk_prot->orphan_count;
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int orphans = percpu_counter_read_positive(ocp);
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if (orphans << shift > sysctl_tcp_max_orphans) {
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orphans = percpu_counter_sum_positive(ocp);
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if (orphans << shift > sysctl_tcp_max_orphans)
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return true;
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}
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return false;
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}
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bool tcp_check_oom(struct sock *sk, int shift);
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extern struct proto tcp_prot;
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#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
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#define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
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#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
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#define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
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#define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
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void tcp_tasklet_init(void);
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void tcp_v4_err(struct sk_buff *skb, u32);
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void tcp_shutdown(struct sock *sk, int how);
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void tcp_v4_early_demux(struct sk_buff *skb);
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int tcp_v4_rcv(struct sk_buff *skb);
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int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
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int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
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int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size,
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int flags);
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void tcp_release_cb(struct sock *sk);
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void tcp_wfree(struct sk_buff *skb);
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void tcp_write_timer_handler(struct sock *sk);
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void tcp_delack_timer_handler(struct sock *sk);
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int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
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int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
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void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
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const struct tcphdr *th, unsigned int len);
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void tcp_rcv_space_adjust(struct sock *sk);
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int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
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void tcp_twsk_destructor(struct sock *sk);
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ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
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struct pipe_inode_info *pipe, size_t len,
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unsigned int flags);
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static inline void tcp_dec_quickack_mode(struct sock *sk,
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const unsigned int pkts)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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if (icsk->icsk_ack.quick) {
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if (pkts >= icsk->icsk_ack.quick) {
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icsk->icsk_ack.quick = 0;
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/* Leaving quickack mode we deflate ATO. */
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icsk->icsk_ack.ato = TCP_ATO_MIN;
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} else
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icsk->icsk_ack.quick -= pkts;
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}
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}
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#define TCP_ECN_OK 1
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#define TCP_ECN_QUEUE_CWR 2
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#define TCP_ECN_DEMAND_CWR 4
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#define TCP_ECN_SEEN 8
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enum tcp_tw_status {
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TCP_TW_SUCCESS = 0,
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TCP_TW_RST = 1,
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TCP_TW_ACK = 2,
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TCP_TW_SYN = 3
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};
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enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
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struct sk_buff *skb,
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const struct tcphdr *th);
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struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
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struct request_sock *req, bool fastopen);
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int tcp_child_process(struct sock *parent, struct sock *child,
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struct sk_buff *skb);
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void tcp_enter_loss(struct sock *sk);
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void tcp_clear_retrans(struct tcp_sock *tp);
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void tcp_update_metrics(struct sock *sk);
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void tcp_init_metrics(struct sock *sk);
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void tcp_metrics_init(void);
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bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst,
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bool paws_check, bool timestamps);
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bool tcp_remember_stamp(struct sock *sk);
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bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw);
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void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst);
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void tcp_disable_fack(struct tcp_sock *tp);
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void tcp_close(struct sock *sk, long timeout);
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void tcp_init_sock(struct sock *sk);
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unsigned int tcp_poll(struct file *file, struct socket *sock,
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struct poll_table_struct *wait);
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int tcp_getsockopt(struct sock *sk, int level, int optname,
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char __user *optval, int __user *optlen);
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int tcp_setsockopt(struct sock *sk, int level, int optname,
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char __user *optval, unsigned int optlen);
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int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
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char __user *optval, int __user *optlen);
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int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
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char __user *optval, unsigned int optlen);
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void tcp_set_keepalive(struct sock *sk, int val);
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void tcp_syn_ack_timeout(const struct request_sock *req);
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int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
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int flags, int *addr_len);
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void tcp_parse_options(const struct sk_buff *skb,
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struct tcp_options_received *opt_rx,
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int estab, struct tcp_fastopen_cookie *foc);
|
|
const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
|
|
|
|
/*
|
|
* TCP v4 functions exported for the inet6 API
|
|
*/
|
|
|
|
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
|
|
void tcp_v4_mtu_reduced(struct sock *sk);
|
|
void tcp_req_err(struct sock *sk, u32 seq, bool abort);
|
|
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
|
|
struct sock *tcp_create_openreq_child(const struct sock *sk,
|
|
struct request_sock *req,
|
|
struct sk_buff *skb);
|
|
void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst);
|
|
struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
|
|
struct request_sock *req,
|
|
struct dst_entry *dst,
|
|
struct request_sock *req_unhash,
|
|
bool *own_req);
|
|
int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
|
|
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
|
|
int tcp_connect(struct sock *sk);
|
|
enum tcp_synack_type {
|
|
TCP_SYNACK_NORMAL,
|
|
TCP_SYNACK_FASTOPEN,
|
|
TCP_SYNACK_COOKIE,
|
|
};
|
|
struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
|
|
struct request_sock *req,
|
|
struct tcp_fastopen_cookie *foc,
|
|
enum tcp_synack_type synack_type);
|
|
int tcp_disconnect(struct sock *sk, int flags);
|
|
|
|
void tcp_finish_connect(struct sock *sk, struct sk_buff *skb);
|
|
int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size);
|
|
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
|
|
|
|
/* From syncookies.c */
|
|
struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
|
|
struct request_sock *req,
|
|
struct dst_entry *dst);
|
|
int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th,
|
|
u32 cookie);
|
|
struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb);
|
|
#ifdef CONFIG_SYN_COOKIES
|
|
|
|
/* Syncookies use a monotonic timer which increments every 60 seconds.
|
|
* This counter is used both as a hash input and partially encoded into
|
|
* the cookie value. A cookie is only validated further if the delta
|
|
* between the current counter value and the encoded one is less than this,
|
|
* i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
|
|
* the counter advances immediately after a cookie is generated).
|
|
*/
|
|
#define MAX_SYNCOOKIE_AGE 2
|
|
#define TCP_SYNCOOKIE_PERIOD (60 * HZ)
|
|
#define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
|
|
|
|
/* syncookies: remember time of last synqueue overflow
|
|
* But do not dirty this field too often (once per second is enough)
|
|
* It is racy as we do not hold a lock, but race is very minor.
|
|
*/
|
|
static inline void tcp_synq_overflow(const struct sock *sk)
|
|
{
|
|
unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
|
|
unsigned long now = jiffies;
|
|
|
|
if (time_after(now, last_overflow + HZ))
|
|
tcp_sk(sk)->rx_opt.ts_recent_stamp = now;
|
|
}
|
|
|
|
/* syncookies: no recent synqueue overflow on this listening socket? */
|
|
static inline bool tcp_synq_no_recent_overflow(const struct sock *sk)
|
|
{
|
|
unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
|
|
|
|
return time_after(jiffies, last_overflow + TCP_SYNCOOKIE_VALID);
|
|
}
|
|
|
|
static inline u32 tcp_cookie_time(void)
|
|
{
|
|
u64 val = get_jiffies_64();
|
|
|
|
do_div(val, TCP_SYNCOOKIE_PERIOD);
|
|
return val;
|
|
}
|
|
|
|
u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
|
|
u16 *mssp);
|
|
__u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
|
|
__u32 cookie_init_timestamp(struct request_sock *req);
|
|
bool cookie_timestamp_decode(struct tcp_options_received *opt);
|
|
bool cookie_ecn_ok(const struct tcp_options_received *opt,
|
|
const struct net *net, const struct dst_entry *dst);
|
|
|
|
/* From net/ipv6/syncookies.c */
|
|
int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
|
|
u32 cookie);
|
|
struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
|
|
|
|
u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
|
|
const struct tcphdr *th, u16 *mssp);
|
|
__u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss);
|
|
#endif
|
|
/* tcp_output.c */
|
|
|
|
void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
|
|
int nonagle);
|
|
bool tcp_may_send_now(struct sock *sk);
|
|
int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
|
|
int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
|
|
void tcp_retransmit_timer(struct sock *sk);
|
|
void tcp_xmit_retransmit_queue(struct sock *);
|
|
void tcp_simple_retransmit(struct sock *);
|
|
int tcp_trim_head(struct sock *, struct sk_buff *, u32);
|
|
int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int, gfp_t);
|
|
|
|
void tcp_send_probe0(struct sock *);
|
|
void tcp_send_partial(struct sock *);
|
|
int tcp_write_wakeup(struct sock *, int mib);
|
|
void tcp_send_fin(struct sock *sk);
|
|
void tcp_send_active_reset(struct sock *sk, gfp_t priority);
|
|
int tcp_send_synack(struct sock *);
|
|
void tcp_push_one(struct sock *, unsigned int mss_now);
|
|
void tcp_send_ack(struct sock *sk);
|
|
void tcp_send_delayed_ack(struct sock *sk);
|
|
void tcp_send_loss_probe(struct sock *sk);
|
|
bool tcp_schedule_loss_probe(struct sock *sk);
|
|
void tcp_skb_collapse_tstamp(struct sk_buff *skb,
|
|
const struct sk_buff *next_skb);
|
|
|
|
/* tcp_input.c */
|
|
void tcp_resume_early_retransmit(struct sock *sk);
|
|
void tcp_rearm_rto(struct sock *sk);
|
|
void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req);
|
|
void tcp_reset(struct sock *sk);
|
|
void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb);
|
|
void tcp_fin(struct sock *sk);
|
|
|
|
/* tcp_timer.c */
|
|
void tcp_init_xmit_timers(struct sock *);
|
|
static inline void tcp_clear_xmit_timers(struct sock *sk)
|
|
{
|
|
inet_csk_clear_xmit_timers(sk);
|
|
}
|
|
|
|
unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
|
|
unsigned int tcp_current_mss(struct sock *sk);
|
|
|
|
/* Bound MSS / TSO packet size with the half of the window */
|
|
static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
|
|
{
|
|
int cutoff;
|
|
|
|
/* When peer uses tiny windows, there is no use in packetizing
|
|
* to sub-MSS pieces for the sake of SWS or making sure there
|
|
* are enough packets in the pipe for fast recovery.
|
|
*
|
|
* On the other hand, for extremely large MSS devices, handling
|
|
* smaller than MSS windows in this way does make sense.
|
|
*/
|
|
if (tp->max_window >= 512)
|
|
cutoff = (tp->max_window >> 1);
|
|
else
|
|
cutoff = tp->max_window;
|
|
|
|
if (cutoff && pktsize > cutoff)
|
|
return max_t(int, cutoff, 68U - tp->tcp_header_len);
|
|
else
|
|
return pktsize;
|
|
}
|
|
|
|
/* tcp.c */
|
|
void tcp_get_info(struct sock *, struct tcp_info *);
|
|
|
|
/* Read 'sendfile()'-style from a TCP socket */
|
|
typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
|
|
unsigned int, size_t);
|
|
int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
|
|
sk_read_actor_t recv_actor);
|
|
|
|
void tcp_initialize_rcv_mss(struct sock *sk);
|
|
|
|
int tcp_mtu_to_mss(struct sock *sk, int pmtu);
|
|
int tcp_mss_to_mtu(struct sock *sk, int mss);
|
|
void tcp_mtup_init(struct sock *sk);
|
|
void tcp_init_buffer_space(struct sock *sk);
|
|
|
|
static inline void tcp_bound_rto(const struct sock *sk)
|
|
{
|
|
if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
|
|
inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
|
|
}
|
|
|
|
static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
|
|
{
|
|
return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us);
|
|
}
|
|
|
|
static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
|
|
{
|
|
tp->pred_flags = htonl((tp->tcp_header_len << 26) |
|
|
ntohl(TCP_FLAG_ACK) |
|
|
snd_wnd);
|
|
}
|
|
|
|
static inline void tcp_fast_path_on(struct tcp_sock *tp)
|
|
{
|
|
__tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
|
|
}
|
|
|
|
static inline void tcp_fast_path_check(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
if (skb_queue_empty(&tp->out_of_order_queue) &&
|
|
tp->rcv_wnd &&
|
|
atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
|
|
!tp->urg_data)
|
|
tcp_fast_path_on(tp);
|
|
}
|
|
|
|
/* Compute the actual rto_min value */
|
|
static inline u32 tcp_rto_min(struct sock *sk)
|
|
{
|
|
const struct dst_entry *dst = __sk_dst_get(sk);
|
|
u32 rto_min = TCP_RTO_MIN;
|
|
|
|
if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
|
|
rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
|
|
return rto_min;
|
|
}
|
|
|
|
static inline u32 tcp_rto_min_us(struct sock *sk)
|
|
{
|
|
return jiffies_to_usecs(tcp_rto_min(sk));
|
|
}
|
|
|
|
static inline bool tcp_ca_dst_locked(const struct dst_entry *dst)
|
|
{
|
|
return dst_metric_locked(dst, RTAX_CC_ALGO);
|
|
}
|
|
|
|
/* Minimum RTT in usec. ~0 means not available. */
|
|
static inline u32 tcp_min_rtt(const struct tcp_sock *tp)
|
|
{
|
|
return tp->rtt_min[0].rtt;
|
|
}
|
|
|
|
/* Compute the actual receive window we are currently advertising.
|
|
* Rcv_nxt can be after the window if our peer push more data
|
|
* than the offered window.
|
|
*/
|
|
static inline u32 tcp_receive_window(const struct tcp_sock *tp)
|
|
{
|
|
s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
|
|
|
|
if (win < 0)
|
|
win = 0;
|
|
return (u32) win;
|
|
}
|
|
|
|
/* Choose a new window, without checks for shrinking, and without
|
|
* scaling applied to the result. The caller does these things
|
|
* if necessary. This is a "raw" window selection.
|
|
*/
|
|
u32 __tcp_select_window(struct sock *sk);
|
|
|
|
void tcp_send_window_probe(struct sock *sk);
|
|
|
|
/* TCP timestamps are only 32-bits, this causes a slight
|
|
* complication on 64-bit systems since we store a snapshot
|
|
* of jiffies in the buffer control blocks below. We decided
|
|
* to use only the low 32-bits of jiffies and hide the ugly
|
|
* casts with the following macro.
|
|
*/
|
|
#define tcp_time_stamp ((__u32)(jiffies))
|
|
|
|
static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
|
|
{
|
|
return skb->skb_mstamp.stamp_jiffies;
|
|
}
|
|
|
|
|
|
#define tcp_flag_byte(th) (((u_int8_t *)th)[13])
|
|
|
|
#define TCPHDR_FIN 0x01
|
|
#define TCPHDR_SYN 0x02
|
|
#define TCPHDR_RST 0x04
|
|
#define TCPHDR_PSH 0x08
|
|
#define TCPHDR_ACK 0x10
|
|
#define TCPHDR_URG 0x20
|
|
#define TCPHDR_ECE 0x40
|
|
#define TCPHDR_CWR 0x80
|
|
|
|
#define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
|
|
|
|
/* This is what the send packet queuing engine uses to pass
|
|
* TCP per-packet control information to the transmission code.
|
|
* We also store the host-order sequence numbers in here too.
|
|
* This is 44 bytes if IPV6 is enabled.
|
|
* If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
|
|
*/
|
|
struct tcp_skb_cb {
|
|
__u32 seq; /* Starting sequence number */
|
|
__u32 end_seq; /* SEQ + FIN + SYN + datalen */
|
|
union {
|
|
/* Note : tcp_tw_isn is used in input path only
|
|
* (isn chosen by tcp_timewait_state_process())
|
|
*
|
|
* tcp_gso_segs/size are used in write queue only,
|
|
* cf tcp_skb_pcount()/tcp_skb_mss()
|
|
*/
|
|
__u32 tcp_tw_isn;
|
|
struct {
|
|
u16 tcp_gso_segs;
|
|
u16 tcp_gso_size;
|
|
};
|
|
};
|
|
__u8 tcp_flags; /* TCP header flags. (tcp[13]) */
|
|
|
|
__u8 sacked; /* State flags for SACK/FACK. */
|
|
#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
|
|
#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
|
|
#define TCPCB_LOST 0x04 /* SKB is lost */
|
|
#define TCPCB_TAGBITS 0x07 /* All tag bits */
|
|
#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */
|
|
#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
|
|
#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
|
|
TCPCB_REPAIRED)
|
|
|
|
__u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
|
|
__u8 txstamp_ack:1, /* Record TX timestamp for ack? */
|
|
unused:7;
|
|
__u32 ack_seq; /* Sequence number ACK'd */
|
|
union {
|
|
struct inet_skb_parm h4;
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
struct inet6_skb_parm h6;
|
|
#endif
|
|
} header; /* For incoming frames */
|
|
};
|
|
|
|
#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
|
|
|
|
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
/* This is the variant of inet6_iif() that must be used by TCP,
|
|
* as TCP moves IP6CB into a different location in skb->cb[]
|
|
*/
|
|
static inline int tcp_v6_iif(const struct sk_buff *skb)
|
|
{
|
|
return TCP_SKB_CB(skb)->header.h6.iif;
|
|
}
|
|
#endif
|
|
|
|
/* Due to TSO, an SKB can be composed of multiple actual
|
|
* packets. To keep these tracked properly, we use this.
|
|
*/
|
|
static inline int tcp_skb_pcount(const struct sk_buff *skb)
|
|
{
|
|
return TCP_SKB_CB(skb)->tcp_gso_segs;
|
|
}
|
|
|
|
static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs)
|
|
{
|
|
TCP_SKB_CB(skb)->tcp_gso_segs = segs;
|
|
}
|
|
|
|
static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs)
|
|
{
|
|
TCP_SKB_CB(skb)->tcp_gso_segs += segs;
|
|
}
|
|
|
|
/* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
|
|
static inline int tcp_skb_mss(const struct sk_buff *skb)
|
|
{
|
|
return TCP_SKB_CB(skb)->tcp_gso_size;
|
|
}
|
|
|
|
/* Events passed to congestion control interface */
|
|
enum tcp_ca_event {
|
|
CA_EVENT_TX_START, /* first transmit when no packets in flight */
|
|
CA_EVENT_CWND_RESTART, /* congestion window restart */
|
|
CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
|
|
CA_EVENT_LOSS, /* loss timeout */
|
|
CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
|
|
CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
|
|
CA_EVENT_DELAYED_ACK, /* Delayed ack is sent */
|
|
CA_EVENT_NON_DELAYED_ACK,
|
|
};
|
|
|
|
/* Information about inbound ACK, passed to cong_ops->in_ack_event() */
|
|
enum tcp_ca_ack_event_flags {
|
|
CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */
|
|
CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */
|
|
CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */
|
|
};
|
|
|
|
/*
|
|
* Interface for adding new TCP congestion control handlers
|
|
*/
|
|
#define TCP_CA_NAME_MAX 16
|
|
#define TCP_CA_MAX 128
|
|
#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
|
|
|
|
#define TCP_CA_UNSPEC 0
|
|
|
|
/* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
|
|
#define TCP_CONG_NON_RESTRICTED 0x1
|
|
/* Requires ECN/ECT set on all packets */
|
|
#define TCP_CONG_NEEDS_ECN 0x2
|
|
|
|
union tcp_cc_info;
|
|
|
|
struct tcp_congestion_ops {
|
|
struct list_head list;
|
|
u32 key;
|
|
u32 flags;
|
|
|
|
/* initialize private data (optional) */
|
|
void (*init)(struct sock *sk);
|
|
/* cleanup private data (optional) */
|
|
void (*release)(struct sock *sk);
|
|
|
|
/* return slow start threshold (required) */
|
|
u32 (*ssthresh)(struct sock *sk);
|
|
/* do new cwnd calculation (required) */
|
|
void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked);
|
|
/* call before changing ca_state (optional) */
|
|
void (*set_state)(struct sock *sk, u8 new_state);
|
|
/* call when cwnd event occurs (optional) */
|
|
void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
|
|
/* call when ack arrives (optional) */
|
|
void (*in_ack_event)(struct sock *sk, u32 flags);
|
|
/* new value of cwnd after loss (optional) */
|
|
u32 (*undo_cwnd)(struct sock *sk);
|
|
/* hook for packet ack accounting (optional) */
|
|
void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
|
|
/* get info for inet_diag (optional) */
|
|
size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
|
|
union tcp_cc_info *info);
|
|
|
|
char name[TCP_CA_NAME_MAX];
|
|
struct module *owner;
|
|
};
|
|
|
|
int tcp_register_congestion_control(struct tcp_congestion_ops *type);
|
|
void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
|
|
|
|
void tcp_assign_congestion_control(struct sock *sk);
|
|
void tcp_init_congestion_control(struct sock *sk);
|
|
void tcp_cleanup_congestion_control(struct sock *sk);
|
|
int tcp_set_default_congestion_control(const char *name);
|
|
void tcp_get_default_congestion_control(char *name);
|
|
void tcp_get_available_congestion_control(char *buf, size_t len);
|
|
void tcp_get_allowed_congestion_control(char *buf, size_t len);
|
|
int tcp_set_allowed_congestion_control(char *allowed);
|
|
int tcp_set_congestion_control(struct sock *sk, const char *name);
|
|
u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
|
|
void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
|
|
|
|
u32 tcp_reno_ssthresh(struct sock *sk);
|
|
void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked);
|
|
extern struct tcp_congestion_ops tcp_reno;
|
|
|
|
struct tcp_congestion_ops *tcp_ca_find_key(u32 key);
|
|
u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca);
|
|
#ifdef CONFIG_INET
|
|
char *tcp_ca_get_name_by_key(u32 key, char *buffer);
|
|
#else
|
|
static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
static inline bool tcp_ca_needs_ecn(const struct sock *sk)
|
|
{
|
|
const struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
|
|
}
|
|
|
|
static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
|
|
{
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
if (icsk->icsk_ca_ops->set_state)
|
|
icsk->icsk_ca_ops->set_state(sk, ca_state);
|
|
icsk->icsk_ca_state = ca_state;
|
|
}
|
|
|
|
static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
|
|
{
|
|
const struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
if (icsk->icsk_ca_ops->cwnd_event)
|
|
icsk->icsk_ca_ops->cwnd_event(sk, event);
|
|
}
|
|
|
|
/* These functions determine how the current flow behaves in respect of SACK
|
|
* handling. SACK is negotiated with the peer, and therefore it can vary
|
|
* between different flows.
|
|
*
|
|
* tcp_is_sack - SACK enabled
|
|
* tcp_is_reno - No SACK
|
|
* tcp_is_fack - FACK enabled, implies SACK enabled
|
|
*/
|
|
static inline int tcp_is_sack(const struct tcp_sock *tp)
|
|
{
|
|
return tp->rx_opt.sack_ok;
|
|
}
|
|
|
|
static inline bool tcp_is_reno(const struct tcp_sock *tp)
|
|
{
|
|
return !tcp_is_sack(tp);
|
|
}
|
|
|
|
static inline bool tcp_is_fack(const struct tcp_sock *tp)
|
|
{
|
|
return tp->rx_opt.sack_ok & TCP_FACK_ENABLED;
|
|
}
|
|
|
|
static inline void tcp_enable_fack(struct tcp_sock *tp)
|
|
{
|
|
tp->rx_opt.sack_ok |= TCP_FACK_ENABLED;
|
|
}
|
|
|
|
/* TCP early-retransmit (ER) is similar to but more conservative than
|
|
* the thin-dupack feature. Enable ER only if thin-dupack is disabled.
|
|
*/
|
|
static inline void tcp_enable_early_retrans(struct tcp_sock *tp)
|
|
{
|
|
struct net *net = sock_net((struct sock *)tp);
|
|
|
|
tp->do_early_retrans = sysctl_tcp_early_retrans &&
|
|
sysctl_tcp_early_retrans < 4 && !sysctl_tcp_thin_dupack &&
|
|
net->ipv4.sysctl_tcp_reordering == 3;
|
|
}
|
|
|
|
static inline void tcp_disable_early_retrans(struct tcp_sock *tp)
|
|
{
|
|
tp->do_early_retrans = 0;
|
|
}
|
|
|
|
static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
|
|
{
|
|
return tp->sacked_out + tp->lost_out;
|
|
}
|
|
|
|
/* This determines how many packets are "in the network" to the best
|
|
* of our knowledge. In many cases it is conservative, but where
|
|
* detailed information is available from the receiver (via SACK
|
|
* blocks etc.) we can make more aggressive calculations.
|
|
*
|
|
* Use this for decisions involving congestion control, use just
|
|
* tp->packets_out to determine if the send queue is empty or not.
|
|
*
|
|
* Read this equation as:
|
|
*
|
|
* "Packets sent once on transmission queue" MINUS
|
|
* "Packets left network, but not honestly ACKed yet" PLUS
|
|
* "Packets fast retransmitted"
|
|
*/
|
|
static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
|
|
{
|
|
return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
|
|
}
|
|
|
|
#define TCP_INFINITE_SSTHRESH 0x7fffffff
|
|
|
|
static inline bool tcp_in_slow_start(const struct tcp_sock *tp)
|
|
{
|
|
return tp->snd_cwnd < tp->snd_ssthresh;
|
|
}
|
|
|
|
static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
|
|
{
|
|
return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
|
|
}
|
|
|
|
static inline bool tcp_in_cwnd_reduction(const struct sock *sk)
|
|
{
|
|
return (TCPF_CA_CWR | TCPF_CA_Recovery) &
|
|
(1 << inet_csk(sk)->icsk_ca_state);
|
|
}
|
|
|
|
/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
|
|
* The exception is cwnd reduction phase, when cwnd is decreasing towards
|
|
* ssthresh.
|
|
*/
|
|
static inline __u32 tcp_current_ssthresh(const struct sock *sk)
|
|
{
|
|
const struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
if (tcp_in_cwnd_reduction(sk))
|
|
return tp->snd_ssthresh;
|
|
else
|
|
return max(tp->snd_ssthresh,
|
|
((tp->snd_cwnd >> 1) +
|
|
(tp->snd_cwnd >> 2)));
|
|
}
|
|
|
|
/* Use define here intentionally to get WARN_ON location shown at the caller */
|
|
#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
|
|
|
|
void tcp_enter_cwr(struct sock *sk);
|
|
__u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst);
|
|
|
|
/* The maximum number of MSS of available cwnd for which TSO defers
|
|
* sending if not using sysctl_tcp_tso_win_divisor.
|
|
*/
|
|
static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp)
|
|
{
|
|
return 3;
|
|
}
|
|
|
|
/* Returns end sequence number of the receiver's advertised window */
|
|
static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
|
|
{
|
|
return tp->snd_una + tp->snd_wnd;
|
|
}
|
|
|
|
/* We follow the spirit of RFC2861 to validate cwnd but implement a more
|
|
* flexible approach. The RFC suggests cwnd should not be raised unless
|
|
* it was fully used previously. And that's exactly what we do in
|
|
* congestion avoidance mode. But in slow start we allow cwnd to grow
|
|
* as long as the application has used half the cwnd.
|
|
* Example :
|
|
* cwnd is 10 (IW10), but application sends 9 frames.
|
|
* We allow cwnd to reach 18 when all frames are ACKed.
|
|
* This check is safe because it's as aggressive as slow start which already
|
|
* risks 100% overshoot. The advantage is that we discourage application to
|
|
* either send more filler packets or data to artificially blow up the cwnd
|
|
* usage, and allow application-limited process to probe bw more aggressively.
|
|
*/
|
|
static inline bool tcp_is_cwnd_limited(const struct sock *sk)
|
|
{
|
|
const struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
/* If in slow start, ensure cwnd grows to twice what was ACKed. */
|
|
if (tcp_in_slow_start(tp))
|
|
return tp->snd_cwnd < 2 * tp->max_packets_out;
|
|
|
|
return tp->is_cwnd_limited;
|
|
}
|
|
|
|
/* Something is really bad, we could not queue an additional packet,
|
|
* because qdisc is full or receiver sent a 0 window.
|
|
* We do not want to add fuel to the fire, or abort too early,
|
|
* so make sure the timer we arm now is at least 200ms in the future,
|
|
* regardless of current icsk_rto value (as it could be ~2ms)
|
|
*/
|
|
static inline unsigned long tcp_probe0_base(const struct sock *sk)
|
|
{
|
|
return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN);
|
|
}
|
|
|
|
/* Variant of inet_csk_rto_backoff() used for zero window probes */
|
|
static inline unsigned long tcp_probe0_when(const struct sock *sk,
|
|
unsigned long max_when)
|
|
{
|
|
u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff;
|
|
|
|
return (unsigned long)min_t(u64, when, max_when);
|
|
}
|
|
|
|
static inline void tcp_check_probe_timer(struct sock *sk)
|
|
{
|
|
if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending)
|
|
inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
|
|
tcp_probe0_base(sk), TCP_RTO_MAX);
|
|
}
|
|
|
|
static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
|
|
{
|
|
tp->snd_wl1 = seq;
|
|
}
|
|
|
|
static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
|
|
{
|
|
tp->snd_wl1 = seq;
|
|
}
|
|
|
|
/*
|
|
* Calculate(/check) TCP checksum
|
|
*/
|
|
static inline __sum16 tcp_v4_check(int len, __be32 saddr,
|
|
__be32 daddr, __wsum base)
|
|
{
|
|
return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
|
|
}
|
|
|
|
static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
|
|
{
|
|
return __skb_checksum_complete(skb);
|
|
}
|
|
|
|
static inline bool tcp_checksum_complete(struct sk_buff *skb)
|
|
{
|
|
return !skb_csum_unnecessary(skb) &&
|
|
__tcp_checksum_complete(skb);
|
|
}
|
|
|
|
/* Prequeue for VJ style copy to user, combined with checksumming. */
|
|
|
|
static inline void tcp_prequeue_init(struct tcp_sock *tp)
|
|
{
|
|
tp->ucopy.task = NULL;
|
|
tp->ucopy.len = 0;
|
|
tp->ucopy.memory = 0;
|
|
skb_queue_head_init(&tp->ucopy.prequeue);
|
|
}
|
|
|
|
bool tcp_prequeue(struct sock *sk, struct sk_buff *skb);
|
|
|
|
#undef STATE_TRACE
|
|
|
|
#ifdef STATE_TRACE
|
|
static const char *statename[]={
|
|
"Unused","Established","Syn Sent","Syn Recv",
|
|
"Fin Wait 1","Fin Wait 2","Time Wait", "Close",
|
|
"Close Wait","Last ACK","Listen","Closing"
|
|
};
|
|
#endif
|
|
void tcp_set_state(struct sock *sk, int state);
|
|
|
|
void tcp_done(struct sock *sk);
|
|
|
|
int tcp_abort(struct sock *sk, int err);
|
|
|
|
static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
|
|
{
|
|
rx_opt->dsack = 0;
|
|
rx_opt->num_sacks = 0;
|
|
}
|
|
|
|
u32 tcp_default_init_rwnd(u32 mss);
|
|
void tcp_cwnd_restart(struct sock *sk, s32 delta);
|
|
|
|
static inline void tcp_slow_start_after_idle_check(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
s32 delta;
|
|
|
|
if (!sysctl_tcp_slow_start_after_idle || tp->packets_out)
|
|
return;
|
|
delta = tcp_time_stamp - tp->lsndtime;
|
|
if (delta > inet_csk(sk)->icsk_rto)
|
|
tcp_cwnd_restart(sk, delta);
|
|
}
|
|
|
|
/* Determine a window scaling and initial window to offer. */
|
|
void tcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
|
|
__u32 *window_clamp, int wscale_ok,
|
|
__u8 *rcv_wscale, __u32 init_rcv_wnd);
|
|
|
|
static inline int tcp_win_from_space(int space)
|
|
{
|
|
return sysctl_tcp_adv_win_scale<=0 ?
|
|
(space>>(-sysctl_tcp_adv_win_scale)) :
|
|
space - (space>>sysctl_tcp_adv_win_scale);
|
|
}
|
|
|
|
/* Note: caller must be prepared to deal with negative returns */
|
|
static inline int tcp_space(const struct sock *sk)
|
|
{
|
|
return tcp_win_from_space(sk->sk_rcvbuf -
|
|
atomic_read(&sk->sk_rmem_alloc));
|
|
}
|
|
|
|
static inline int tcp_full_space(const struct sock *sk)
|
|
{
|
|
return tcp_win_from_space(sk->sk_rcvbuf);
|
|
}
|
|
|
|
extern void tcp_openreq_init_rwin(struct request_sock *req,
|
|
const struct sock *sk_listener,
|
|
const struct dst_entry *dst);
|
|
|
|
void tcp_enter_memory_pressure(struct sock *sk);
|
|
|
|
static inline int keepalive_intvl_when(const struct tcp_sock *tp)
|
|
{
|
|
struct net *net = sock_net((struct sock *)tp);
|
|
|
|
return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl;
|
|
}
|
|
|
|
static inline int keepalive_time_when(const struct tcp_sock *tp)
|
|
{
|
|
struct net *net = sock_net((struct sock *)tp);
|
|
|
|
return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time;
|
|
}
|
|
|
|
static inline int keepalive_probes(const struct tcp_sock *tp)
|
|
{
|
|
struct net *net = sock_net((struct sock *)tp);
|
|
|
|
return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes;
|
|
}
|
|
|
|
static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
|
|
{
|
|
const struct inet_connection_sock *icsk = &tp->inet_conn;
|
|
|
|
return min_t(u32, tcp_time_stamp - icsk->icsk_ack.lrcvtime,
|
|
tcp_time_stamp - tp->rcv_tstamp);
|
|
}
|
|
|
|
static inline int tcp_fin_time(const struct sock *sk)
|
|
{
|
|
int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout;
|
|
const int rto = inet_csk(sk)->icsk_rto;
|
|
|
|
if (fin_timeout < (rto << 2) - (rto >> 1))
|
|
fin_timeout = (rto << 2) - (rto >> 1);
|
|
|
|
return fin_timeout;
|
|
}
|
|
|
|
static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt,
|
|
int paws_win)
|
|
{
|
|
if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
|
|
return true;
|
|
if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
|
|
return true;
|
|
/*
|
|
* Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
|
|
* then following tcp messages have valid values. Ignore 0 value,
|
|
* or else 'negative' tsval might forbid us to accept their packets.
|
|
*/
|
|
if (!rx_opt->ts_recent)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
|
|
int rst)
|
|
{
|
|
if (tcp_paws_check(rx_opt, 0))
|
|
return false;
|
|
|
|
/* RST segments are not recommended to carry timestamp,
|
|
and, if they do, it is recommended to ignore PAWS because
|
|
"their cleanup function should take precedence over timestamps."
|
|
Certainly, it is mistake. It is necessary to understand the reasons
|
|
of this constraint to relax it: if peer reboots, clock may go
|
|
out-of-sync and half-open connections will not be reset.
|
|
Actually, the problem would be not existing if all
|
|
the implementations followed draft about maintaining clock
|
|
via reboots. Linux-2.2 DOES NOT!
|
|
|
|
However, we can relax time bounds for RST segments to MSL.
|
|
*/
|
|
if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
|
|
int mib_idx, u32 *last_oow_ack_time);
|
|
|
|
static inline void tcp_mib_init(struct net *net)
|
|
{
|
|
/* See RFC 2012 */
|
|
TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
|
|
TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
|
|
TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
|
|
TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
|
|
}
|
|
|
|
/* from STCP */
|
|
static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
|
|
{
|
|
tp->lost_skb_hint = NULL;
|
|
}
|
|
|
|
static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
|
|
{
|
|
tcp_clear_retrans_hints_partial(tp);
|
|
tp->retransmit_skb_hint = NULL;
|
|
}
|
|
|
|
union tcp_md5_addr {
|
|
struct in_addr a4;
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
struct in6_addr a6;
|
|
#endif
|
|
};
|
|
|
|
/* - key database */
|
|
struct tcp_md5sig_key {
|
|
struct hlist_node node;
|
|
u8 keylen;
|
|
u8 family; /* AF_INET or AF_INET6 */
|
|
union tcp_md5_addr addr;
|
|
u8 key[TCP_MD5SIG_MAXKEYLEN];
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
/* - sock block */
|
|
struct tcp_md5sig_info {
|
|
struct hlist_head head;
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
/* - pseudo header */
|
|
struct tcp4_pseudohdr {
|
|
__be32 saddr;
|
|
__be32 daddr;
|
|
__u8 pad;
|
|
__u8 protocol;
|
|
__be16 len;
|
|
};
|
|
|
|
struct tcp6_pseudohdr {
|
|
struct in6_addr saddr;
|
|
struct in6_addr daddr;
|
|
__be32 len;
|
|
__be32 protocol; /* including padding */
|
|
};
|
|
|
|
union tcp_md5sum_block {
|
|
struct tcp4_pseudohdr ip4;
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
struct tcp6_pseudohdr ip6;
|
|
#endif
|
|
};
|
|
|
|
/* - pool: digest algorithm, hash description and scratch buffer */
|
|
struct tcp_md5sig_pool {
|
|
struct ahash_request *md5_req;
|
|
union tcp_md5sum_block md5_blk;
|
|
};
|
|
|
|
/* - functions */
|
|
int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
|
|
const struct sock *sk, const struct sk_buff *skb);
|
|
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
|
|
int family, const u8 *newkey, u8 newkeylen, gfp_t gfp);
|
|
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
|
|
int family);
|
|
struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
|
|
const struct sock *addr_sk);
|
|
|
|
#ifdef CONFIG_TCP_MD5SIG
|
|
struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
|
|
const union tcp_md5_addr *addr,
|
|
int family);
|
|
#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
|
|
#else
|
|
static inline struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
|
|
const union tcp_md5_addr *addr,
|
|
int family)
|
|
{
|
|
return NULL;
|
|
}
|
|
#define tcp_twsk_md5_key(twsk) NULL
|
|
#endif
|
|
|
|
bool tcp_alloc_md5sig_pool(void);
|
|
|
|
struct tcp_md5sig_pool *tcp_get_md5sig_pool(void);
|
|
static inline void tcp_put_md5sig_pool(void)
|
|
{
|
|
local_bh_enable();
|
|
}
|
|
|
|
int tcp_md5_hash_header(struct tcp_md5sig_pool *, const struct tcphdr *);
|
|
int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *,
|
|
unsigned int header_len);
|
|
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
|
|
const struct tcp_md5sig_key *key);
|
|
|
|
/* From tcp_fastopen.c */
|
|
void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
|
|
struct tcp_fastopen_cookie *cookie, int *syn_loss,
|
|
unsigned long *last_syn_loss);
|
|
void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
|
|
struct tcp_fastopen_cookie *cookie, bool syn_lost,
|
|
u16 try_exp);
|
|
struct tcp_fastopen_request {
|
|
/* Fast Open cookie. Size 0 means a cookie request */
|
|
struct tcp_fastopen_cookie cookie;
|
|
struct msghdr *data; /* data in MSG_FASTOPEN */
|
|
size_t size;
|
|
int copied; /* queued in tcp_connect() */
|
|
};
|
|
void tcp_free_fastopen_req(struct tcp_sock *tp);
|
|
|
|
extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
|
|
int tcp_fastopen_reset_cipher(void *key, unsigned int len);
|
|
void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
|
|
struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
|
|
struct request_sock *req,
|
|
struct tcp_fastopen_cookie *foc,
|
|
struct dst_entry *dst);
|
|
void tcp_fastopen_init_key_once(bool publish);
|
|
#define TCP_FASTOPEN_KEY_LENGTH 16
|
|
|
|
/* Fastopen key context */
|
|
struct tcp_fastopen_context {
|
|
struct crypto_cipher *tfm;
|
|
__u8 key[TCP_FASTOPEN_KEY_LENGTH];
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
/* write queue abstraction */
|
|
static inline void tcp_write_queue_purge(struct sock *sk)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
|
|
sk_wmem_free_skb(sk, skb);
|
|
sk_mem_reclaim(sk);
|
|
tcp_clear_all_retrans_hints(tcp_sk(sk));
|
|
}
|
|
|
|
static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk)
|
|
{
|
|
return skb_peek(&sk->sk_write_queue);
|
|
}
|
|
|
|
static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk)
|
|
{
|
|
return skb_peek_tail(&sk->sk_write_queue);
|
|
}
|
|
|
|
static inline struct sk_buff *tcp_write_queue_next(const struct sock *sk,
|
|
const struct sk_buff *skb)
|
|
{
|
|
return skb_queue_next(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
static inline struct sk_buff *tcp_write_queue_prev(const struct sock *sk,
|
|
const struct sk_buff *skb)
|
|
{
|
|
return skb_queue_prev(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
#define tcp_for_write_queue(skb, sk) \
|
|
skb_queue_walk(&(sk)->sk_write_queue, skb)
|
|
|
|
#define tcp_for_write_queue_from(skb, sk) \
|
|
skb_queue_walk_from(&(sk)->sk_write_queue, skb)
|
|
|
|
#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
|
|
skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
|
|
|
|
static inline struct sk_buff *tcp_send_head(const struct sock *sk)
|
|
{
|
|
return sk->sk_send_head;
|
|
}
|
|
|
|
static inline bool tcp_skb_is_last(const struct sock *sk,
|
|
const struct sk_buff *skb)
|
|
{
|
|
return skb_queue_is_last(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
static inline void tcp_advance_send_head(struct sock *sk, const struct sk_buff *skb)
|
|
{
|
|
if (tcp_skb_is_last(sk, skb))
|
|
sk->sk_send_head = NULL;
|
|
else
|
|
sk->sk_send_head = tcp_write_queue_next(sk, skb);
|
|
}
|
|
|
|
static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
|
|
{
|
|
if (sk->sk_send_head == skb_unlinked)
|
|
sk->sk_send_head = NULL;
|
|
}
|
|
|
|
static inline void tcp_init_send_head(struct sock *sk)
|
|
{
|
|
sk->sk_send_head = NULL;
|
|
}
|
|
|
|
static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
__skb_queue_tail(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
__tcp_add_write_queue_tail(sk, skb);
|
|
|
|
/* Queue it, remembering where we must start sending. */
|
|
if (sk->sk_send_head == NULL) {
|
|
sk->sk_send_head = skb;
|
|
|
|
if (tcp_sk(sk)->highest_sack == NULL)
|
|
tcp_sk(sk)->highest_sack = skb;
|
|
}
|
|
}
|
|
|
|
static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
__skb_queue_head(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
/* Insert buff after skb on the write queue of sk. */
|
|
static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
|
|
struct sk_buff *buff,
|
|
struct sock *sk)
|
|
{
|
|
__skb_queue_after(&sk->sk_write_queue, skb, buff);
|
|
}
|
|
|
|
/* Insert new before skb on the write queue of sk. */
|
|
static inline void tcp_insert_write_queue_before(struct sk_buff *new,
|
|
struct sk_buff *skb,
|
|
struct sock *sk)
|
|
{
|
|
__skb_queue_before(&sk->sk_write_queue, skb, new);
|
|
|
|
if (sk->sk_send_head == skb)
|
|
sk->sk_send_head = new;
|
|
}
|
|
|
|
static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
|
|
{
|
|
__skb_unlink(skb, &sk->sk_write_queue);
|
|
}
|
|
|
|
static inline bool tcp_write_queue_empty(struct sock *sk)
|
|
{
|
|
return skb_queue_empty(&sk->sk_write_queue);
|
|
}
|
|
|
|
static inline void tcp_push_pending_frames(struct sock *sk)
|
|
{
|
|
if (tcp_send_head(sk)) {
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
__tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
|
|
}
|
|
}
|
|
|
|
/* Start sequence of the skb just after the highest skb with SACKed
|
|
* bit, valid only if sacked_out > 0 or when the caller has ensured
|
|
* validity by itself.
|
|
*/
|
|
static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
|
|
{
|
|
if (!tp->sacked_out)
|
|
return tp->snd_una;
|
|
|
|
if (tp->highest_sack == NULL)
|
|
return tp->snd_nxt;
|
|
|
|
return TCP_SKB_CB(tp->highest_sack)->seq;
|
|
}
|
|
|
|
static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
|
|
tcp_write_queue_next(sk, skb);
|
|
}
|
|
|
|
static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
|
|
{
|
|
return tcp_sk(sk)->highest_sack;
|
|
}
|
|
|
|
static inline void tcp_highest_sack_reset(struct sock *sk)
|
|
{
|
|
tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
|
|
}
|
|
|
|
/* Called when old skb is about to be deleted (to be combined with new skb) */
|
|
static inline void tcp_highest_sack_combine(struct sock *sk,
|
|
struct sk_buff *old,
|
|
struct sk_buff *new)
|
|
{
|
|
if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
|
|
tcp_sk(sk)->highest_sack = new;
|
|
}
|
|
|
|
/* This helper checks if socket has IP_TRANSPARENT set */
|
|
static inline bool inet_sk_transparent(const struct sock *sk)
|
|
{
|
|
switch (sk->sk_state) {
|
|
case TCP_TIME_WAIT:
|
|
return inet_twsk(sk)->tw_transparent;
|
|
case TCP_NEW_SYN_RECV:
|
|
return inet_rsk(inet_reqsk(sk))->no_srccheck;
|
|
}
|
|
return inet_sk(sk)->transparent;
|
|
}
|
|
|
|
/* Determines whether this is a thin stream (which may suffer from
|
|
* increased latency). Used to trigger latency-reducing mechanisms.
|
|
*/
|
|
static inline bool tcp_stream_is_thin(struct tcp_sock *tp)
|
|
{
|
|
return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp);
|
|
}
|
|
|
|
/* /proc */
|
|
enum tcp_seq_states {
|
|
TCP_SEQ_STATE_LISTENING,
|
|
TCP_SEQ_STATE_ESTABLISHED,
|
|
};
|
|
|
|
int tcp_seq_open(struct inode *inode, struct file *file);
|
|
|
|
struct tcp_seq_afinfo {
|
|
char *name;
|
|
sa_family_t family;
|
|
const struct file_operations *seq_fops;
|
|
struct seq_operations seq_ops;
|
|
};
|
|
|
|
struct tcp_iter_state {
|
|
struct seq_net_private p;
|
|
sa_family_t family;
|
|
enum tcp_seq_states state;
|
|
struct sock *syn_wait_sk;
|
|
int bucket, offset, sbucket, num;
|
|
loff_t last_pos;
|
|
};
|
|
|
|
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
|
|
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
|
|
|
|
extern struct request_sock_ops tcp_request_sock_ops;
|
|
extern struct request_sock_ops tcp6_request_sock_ops;
|
|
|
|
void tcp_v4_destroy_sock(struct sock *sk);
|
|
|
|
struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
|
|
netdev_features_t features);
|
|
struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb);
|
|
int tcp_gro_complete(struct sk_buff *skb);
|
|
|
|
void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
|
|
|
|
static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
|
|
{
|
|
struct net *net = sock_net((struct sock *)tp);
|
|
return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat;
|
|
}
|
|
|
|
static inline bool tcp_stream_memory_free(const struct sock *sk)
|
|
{
|
|
const struct tcp_sock *tp = tcp_sk(sk);
|
|
u32 notsent_bytes = tp->write_seq - tp->snd_nxt;
|
|
|
|
return notsent_bytes < tcp_notsent_lowat(tp);
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
int tcp4_proc_init(void);
|
|
void tcp4_proc_exit(void);
|
|
#endif
|
|
|
|
int tcp_rtx_synack(const struct sock *sk, struct request_sock *req);
|
|
int tcp_conn_request(struct request_sock_ops *rsk_ops,
|
|
const struct tcp_request_sock_ops *af_ops,
|
|
struct sock *sk, struct sk_buff *skb);
|
|
|
|
/* TCP af-specific functions */
|
|
struct tcp_sock_af_ops {
|
|
#ifdef CONFIG_TCP_MD5SIG
|
|
struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk,
|
|
const struct sock *addr_sk);
|
|
int (*calc_md5_hash)(char *location,
|
|
const struct tcp_md5sig_key *md5,
|
|
const struct sock *sk,
|
|
const struct sk_buff *skb);
|
|
int (*md5_parse)(struct sock *sk,
|
|
char __user *optval,
|
|
int optlen);
|
|
#endif
|
|
};
|
|
|
|
struct tcp_request_sock_ops {
|
|
u16 mss_clamp;
|
|
#ifdef CONFIG_TCP_MD5SIG
|
|
struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk,
|
|
const struct sock *addr_sk);
|
|
int (*calc_md5_hash) (char *location,
|
|
const struct tcp_md5sig_key *md5,
|
|
const struct sock *sk,
|
|
const struct sk_buff *skb);
|
|
#endif
|
|
void (*init_req)(struct request_sock *req,
|
|
const struct sock *sk_listener,
|
|
struct sk_buff *skb);
|
|
#ifdef CONFIG_SYN_COOKIES
|
|
__u32 (*cookie_init_seq)(const struct sk_buff *skb,
|
|
__u16 *mss);
|
|
#endif
|
|
struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl,
|
|
const struct request_sock *req,
|
|
bool *strict);
|
|
__u32 (*init_seq)(const struct sk_buff *skb);
|
|
int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
|
|
struct flowi *fl, struct request_sock *req,
|
|
struct tcp_fastopen_cookie *foc,
|
|
enum tcp_synack_type synack_type);
|
|
};
|
|
|
|
#ifdef CONFIG_SYN_COOKIES
|
|
static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
|
|
const struct sock *sk, struct sk_buff *skb,
|
|
__u16 *mss)
|
|
{
|
|
tcp_synq_overflow(sk);
|
|
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);
|
|
return ops->cookie_init_seq(skb, mss);
|
|
}
|
|
#else
|
|
static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
|
|
const struct sock *sk, struct sk_buff *skb,
|
|
__u16 *mss)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
int tcpv4_offload_init(void);
|
|
|
|
void tcp_v4_init(void);
|
|
void tcp_init(void);
|
|
|
|
/* tcp_recovery.c */
|
|
|
|
/* Flags to enable various loss recovery features. See below */
|
|
extern int sysctl_tcp_recovery;
|
|
|
|
/* Use TCP RACK to detect (some) tail and retransmit losses */
|
|
#define TCP_RACK_LOST_RETRANS 0x1
|
|
|
|
extern int tcp_rack_mark_lost(struct sock *sk);
|
|
|
|
extern void tcp_rack_advance(struct tcp_sock *tp,
|
|
const struct skb_mstamp *xmit_time, u8 sacked);
|
|
|
|
/*
|
|
* Save and compile IPv4 options, return a pointer to it
|
|
*/
|
|
static inline struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
|
|
{
|
|
const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt;
|
|
struct ip_options_rcu *dopt = NULL;
|
|
|
|
if (opt->optlen) {
|
|
int opt_size = sizeof(*dopt) + opt->optlen;
|
|
|
|
dopt = kmalloc(opt_size, GFP_ATOMIC);
|
|
if (dopt && __ip_options_echo(&dopt->opt, skb, opt)) {
|
|
kfree(dopt);
|
|
dopt = NULL;
|
|
}
|
|
}
|
|
return dopt;
|
|
}
|
|
|
|
/* locally generated TCP pure ACKs have skb->truesize == 2
|
|
* (check tcp_send_ack() in net/ipv4/tcp_output.c )
|
|
* This is much faster than dissecting the packet to find out.
|
|
* (Think of GRE encapsulations, IPv4, IPv6, ...)
|
|
*/
|
|
static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb)
|
|
{
|
|
return skb->truesize == 2;
|
|
}
|
|
|
|
static inline void skb_set_tcp_pure_ack(struct sk_buff *skb)
|
|
{
|
|
skb->truesize = 2;
|
|
}
|
|
|
|
static inline int tcp_inq(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
int answ;
|
|
|
|
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
|
|
answ = 0;
|
|
} else if (sock_flag(sk, SOCK_URGINLINE) ||
|
|
!tp->urg_data ||
|
|
before(tp->urg_seq, tp->copied_seq) ||
|
|
!before(tp->urg_seq, tp->rcv_nxt)) {
|
|
|
|
answ = tp->rcv_nxt - tp->copied_seq;
|
|
|
|
/* Subtract 1, if FIN was received */
|
|
if (answ && sock_flag(sk, SOCK_DONE))
|
|
answ--;
|
|
} else {
|
|
answ = tp->urg_seq - tp->copied_seq;
|
|
}
|
|
|
|
return answ;
|
|
}
|
|
|
|
static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
|
|
{
|
|
u16 segs_in;
|
|
|
|
segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
|
|
tp->segs_in += segs_in;
|
|
if (skb->len > tcp_hdrlen(skb))
|
|
tp->data_segs_in += segs_in;
|
|
}
|
|
|
|
/*
|
|
* TCP listen path runs lockless.
|
|
* We forced "struct sock" to be const qualified to make sure
|
|
* we don't modify one of its field by mistake.
|
|
* Here, we increment sk_drops which is an atomic_t, so we can safely
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* make sock writable again.
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*/
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static inline void tcp_listendrop(const struct sock *sk)
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{
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|
atomic_inc(&((struct sock *)sk)->sk_drops);
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|
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
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}
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#endif /* _TCP_H */
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