| /* |
| * 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. |
| * |
| * Definitions for the TCP module. |
| * |
| * Version: @(#)tcp.h 1.0.5 05/23/93 |
| * |
| * Authors: Ross Biro |
| * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
| * |
| * 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. |
| */ |
| #ifndef _TCP_H |
| #define _TCP_H |
| |
| #define FASTRETRANS_DEBUG 1 |
| |
| #include <linux/list.h> |
| #include <linux/tcp.h> |
| #include <linux/bug.h> |
| #include <linux/slab.h> |
| #include <linux/cache.h> |
| #include <linux/percpu.h> |
| #include <linux/skbuff.h> |
| #include <linux/crypto.h> |
| #include <linux/cryptohash.h> |
| #include <linux/kref.h> |
| #include <linux/ktime.h> |
| |
| #include <net/inet_connection_sock.h> |
| #include <net/inet_timewait_sock.h> |
| #include <net/inet_hashtables.h> |
| #include <net/checksum.h> |
| #include <net/request_sock.h> |
| #include <net/sock.h> |
| #include <net/snmp.h> |
| #include <net/ip.h> |
| #include <net/tcp_states.h> |
| #include <net/inet_ecn.h> |
| #include <net/dst.h> |
| |
| #include <linux/seq_file.h> |
| #include <linux/memcontrol.h> |
| |
| extern struct inet_hashinfo tcp_hashinfo; |
| |
| extern struct percpu_counter tcp_orphan_count; |
| void tcp_time_wait(struct sock *sk, int state, int timeo); |
| |
| #define MAX_TCP_HEADER (128 + MAX_HEADER) |
| #define MAX_TCP_OPTION_SPACE 40 |
| |
| /* |
| * Never offer a window over 32767 without using window scaling. Some |
| * poor stacks do signed 16bit maths! |
| */ |
| #define MAX_TCP_WINDOW 32767U |
| |
| /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ |
| #define TCP_MIN_MSS 88U |
| |
| /* The least MTU to use for probing */ |
| #define TCP_BASE_MSS 512 |
| |
| /* After receiving this amount of duplicate ACKs fast retransmit starts. */ |
| #define TCP_FASTRETRANS_THRESH 3 |
| |
| /* Maximal number of ACKs sent quickly to accelerate slow-start. */ |
| #define TCP_MAX_QUICKACKS 16U |
| |
| /* urg_data states */ |
| #define TCP_URG_VALID 0x0100 |
| #define TCP_URG_NOTYET 0x0200 |
| #define TCP_URG_READ 0x0400 |
| |
| #define TCP_RETR1 3 /* |
| * This is how many retries it does before it |
| * tries to figure out if the gateway is |
| * down. Minimal RFC value is 3; it corresponds |
| * to ~3sec-8min depending on RTO. |
| */ |
| |
| #define TCP_RETR2 15 /* |
| * This should take at least |
| * 90 minutes to time out. |
| * RFC1122 says that the limit is 100 sec. |
| * 15 is ~13-30min depending on RTO. |
| */ |
| |
| #define TCP_SYN_RETRIES 6 /* This is how many retries are done |
| * when active opening a connection. |
| * RFC1122 says the minimum retry MUST |
| * be at least 180secs. Nevertheless |
| * this value is corresponding to |
| * 63secs of retransmission with the |
| * current initial RTO. |
| */ |
| |
| #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done |
| * when passive opening a connection. |
| * This is corresponding to 31secs of |
| * retransmission with the current |
| * initial RTO. |
| */ |
| |
| #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT |
| * state, about 60 seconds */ |
| #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN |
| /* BSD style FIN_WAIT2 deadlock breaker. |
| * It used to be 3min, new value is 60sec, |
| * to combine FIN-WAIT-2 timeout with |
| * TIME-WAIT timer. |
| */ |
| |
| #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ |
| #if HZ >= 100 |
| #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ |
| #define TCP_ATO_MIN ((unsigned)(HZ/25)) |
| #else |
| #define TCP_DELACK_MIN 4U |
| #define TCP_ATO_MIN 4U |
| #endif |
| #define TCP_RTO_MAX ((unsigned)(120*HZ)) |
| #define TCP_RTO_MIN ((unsigned)(HZ/5)) |
| #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ |
| #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now |
| * used as a fallback RTO for the |
| * initial data transmission if no |
| * valid RTT sample has been acquired, |
| * most likely due to retrans in 3WHS. |
| */ |
| |
| #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes |
| * for local resources. |
| */ |
| |
| #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ |
| #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ |
| #define TCP_KEEPALIVE_INTVL (75*HZ) |
| |
| #define MAX_TCP_KEEPIDLE 32767 |
| #define MAX_TCP_KEEPINTVL 32767 |
| #define MAX_TCP_KEEPCNT 127 |
| #define MAX_TCP_SYNCNT 127 |
| |
| #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ |
| |
| #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) |
| #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated |
| * after this time. It should be equal |
| * (or greater than) TCP_TIMEWAIT_LEN |
| * to provide reliability equal to one |
| * provided by timewait state. |
| */ |
| #define TCP_PAWS_WINDOW 1 /* Replay window for per-host |
| * timestamps. It must be less than |
| * minimal timewait lifetime. |
| */ |
| /* |
| * TCP option |
| */ |
| |
| #define TCPOPT_NOP 1 /* Padding */ |
| #define TCPOPT_EOL 0 /* End of options */ |
| #define TCPOPT_MSS 2 /* Segment size negotiating */ |
| #define TCPOPT_WINDOW 3 /* Window scaling */ |
| #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ |
| #define TCPOPT_SACK 5 /* SACK Block */ |
| #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ |
| #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ |
| #define TCPOPT_EXP 254 /* Experimental */ |
| /* Magic number to be after the option value for sharing TCP |
| * experimental options. See draft-ietf-tcpm-experimental-options-00.txt |
| */ |
| #define TCPOPT_FASTOPEN_MAGIC 0xF989 |
| |
| /* |
| * TCP option lengths |
| */ |
| |
| #define TCPOLEN_MSS 4 |
| #define TCPOLEN_WINDOW 3 |
| #define TCPOLEN_SACK_PERM 2 |
| #define TCPOLEN_TIMESTAMP 10 |
| #define TCPOLEN_MD5SIG 18 |
| #define TCPOLEN_EXP_FASTOPEN_BASE 4 |
| |
| /* But this is what stacks really send out. */ |
| #define TCPOLEN_TSTAMP_ALIGNED 12 |
| #define TCPOLEN_WSCALE_ALIGNED 4 |
| #define TCPOLEN_SACKPERM_ALIGNED 4 |
| #define TCPOLEN_SACK_BASE 2 |
| #define TCPOLEN_SACK_BASE_ALIGNED 4 |
| #define TCPOLEN_SACK_PERBLOCK 8 |
| #define TCPOLEN_MD5SIG_ALIGNED 20 |
| #define TCPOLEN_MSS_ALIGNED 4 |
| |
| /* Flags in tp->nonagle */ |
| #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ |
| #define TCP_NAGLE_CORK 2 /* Socket is corked */ |
| #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ |
| |
| /* TCP thin-stream limits */ |
| #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ |
| |
| /* TCP initial congestion window as per draft-hkchu-tcpm-initcwnd-01 */ |
| #define TCP_INIT_CWND 10 |
| |
| /* Bit Flags for sysctl_tcp_fastopen */ |
| #define TFO_CLIENT_ENABLE 1 |
| #define TFO_SERVER_ENABLE 2 |
| #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ |
| |
| /* Accept SYN data w/o any cookie option */ |
| #define TFO_SERVER_COOKIE_NOT_REQD 0x200 |
| |
| /* Force enable TFO on all listeners, i.e., not requiring the |
| * TCP_FASTOPEN socket option. SOCKOPT1/2 determine how to set max_qlen. |
| */ |
| #define TFO_SERVER_WO_SOCKOPT1 0x400 |
| #define TFO_SERVER_WO_SOCKOPT2 0x800 |
| |
| extern struct inet_timewait_death_row tcp_death_row; |
| |
| /* sysctl variables for tcp */ |
| extern int sysctl_tcp_timestamps; |
| extern int sysctl_tcp_window_scaling; |
| extern int sysctl_tcp_sack; |
| extern int sysctl_tcp_fin_timeout; |
| extern int sysctl_tcp_keepalive_time; |
| extern int sysctl_tcp_keepalive_probes; |
| extern int sysctl_tcp_keepalive_intvl; |
| extern int sysctl_tcp_syn_retries; |
| extern int sysctl_tcp_synack_retries; |
| extern int sysctl_tcp_retries1; |
| extern int sysctl_tcp_retries2; |
| extern int sysctl_tcp_orphan_retries; |
| extern int sysctl_tcp_syncookies; |
| extern int sysctl_tcp_fastopen; |
| extern int sysctl_tcp_retrans_collapse; |
| extern int sysctl_tcp_stdurg; |
| extern int sysctl_tcp_rfc1337; |
| extern int sysctl_tcp_abort_on_overflow; |
| extern int sysctl_tcp_max_orphans; |
| extern int sysctl_tcp_fack; |
| extern int sysctl_tcp_reordering; |
| extern int sysctl_tcp_max_reordering; |
| extern int sysctl_tcp_dsack; |
| extern long sysctl_tcp_mem[3]; |
| extern int sysctl_tcp_wmem[3]; |
| extern int sysctl_tcp_rmem[3]; |
| extern int sysctl_tcp_app_win; |
| extern int sysctl_tcp_adv_win_scale; |
| extern int sysctl_tcp_tw_reuse; |
| extern int sysctl_tcp_frto; |
| extern int sysctl_tcp_low_latency; |
| extern int sysctl_tcp_nometrics_save; |
| extern int sysctl_tcp_moderate_rcvbuf; |
| extern int sysctl_tcp_tso_win_divisor; |
| extern int sysctl_tcp_mtu_probing; |
| extern int sysctl_tcp_base_mss; |
| extern int sysctl_tcp_workaround_signed_windows; |
| extern int sysctl_tcp_slow_start_after_idle; |
| extern int sysctl_tcp_thin_linear_timeouts; |
| extern int sysctl_tcp_thin_dupack; |
| extern int sysctl_tcp_early_retrans; |
| extern int sysctl_tcp_limit_output_bytes; |
| extern int sysctl_tcp_challenge_ack_limit; |
| extern unsigned int sysctl_tcp_notsent_lowat; |
| extern int sysctl_tcp_min_tso_segs; |
| extern int sysctl_tcp_autocorking; |
| |
| extern atomic_long_t tcp_memory_allocated; |
| extern struct percpu_counter tcp_sockets_allocated; |
| extern int tcp_memory_pressure; |
| |
| /* |
| * The next routines deal with comparing 32 bit unsigned ints |
| * and worry about wraparound (automatic with unsigned arithmetic). |
| */ |
| |
| static inline bool before(__u32 seq1, __u32 seq2) |
| { |
| return (__s32)(seq1-seq2) < 0; |
| } |
| #define after(seq2, seq1) before(seq1, seq2) |
| |
| /* is s2<=s1<=s3 ? */ |
| static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) |
| { |
| return seq3 - seq2 >= seq1 - seq2; |
| } |
| |
| static inline bool tcp_out_of_memory(struct sock *sk) |
| { |
| if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && |
| sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) |
| return true; |
| return false; |
| } |
| |
| static inline bool tcp_too_many_orphans(struct sock *sk, int shift) |
| { |
| struct percpu_counter *ocp = sk->sk_prot->orphan_count; |
| int orphans = percpu_counter_read_positive(ocp); |
| |
| if (orphans << shift > sysctl_tcp_max_orphans) { |
| orphans = percpu_counter_sum_positive(ocp); |
| if (orphans << shift > sysctl_tcp_max_orphans) |
| return true; |
| } |
| return false; |
| } |
| |
| bool tcp_check_oom(struct sock *sk, int shift); |
| |
| /* syncookies: remember time of last synqueue overflow */ |
| static inline void tcp_synq_overflow(struct sock *sk) |
| { |
| tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies; |
| } |
| |
| /* 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_TIMEOUT_FALLBACK); |
| } |
| |
| extern struct proto tcp_prot; |
| |
| #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) |
| #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field) |
| #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) |
| #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val) |
| #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) |
| |
| void tcp_tasklet_init(void); |
| |
| void tcp_v4_err(struct sk_buff *skb, u32); |
| |
| void tcp_shutdown(struct sock *sk, int how); |
| |
| void tcp_v4_early_demux(struct sk_buff *skb); |
| int tcp_v4_rcv(struct sk_buff *skb); |
| |
| int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); |
| int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, |
| size_t size); |
| int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, |
| int flags); |
| void tcp_release_cb(struct sock *sk); |
| void tcp_wfree(struct sk_buff *skb); |
| void tcp_write_timer_handler(struct sock *sk); |
| void tcp_delack_timer_handler(struct sock *sk); |
| int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); |
| int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, |
| const struct tcphdr *th, unsigned int len); |
| void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, |
| const struct tcphdr *th, unsigned int len); |
| void tcp_rcv_space_adjust(struct sock *sk); |
| int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); |
| void tcp_twsk_destructor(struct sock *sk); |
| ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, |
| struct pipe_inode_info *pipe, size_t len, |
| unsigned int flags); |
| |
| static inline void tcp_dec_quickack_mode(struct sock *sk, |
| const unsigned int pkts) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| if (icsk->icsk_ack.quick) { |
| if (pkts >= icsk->icsk_ack.quick) { |
| icsk->icsk_ack.quick = 0; |
| /* Leaving quickack mode we deflate ATO. */ |
| icsk->icsk_ack.ato = TCP_ATO_MIN; |
| } else |
| icsk->icsk_ack.quick -= pkts; |
| } |
| } |
| |
| #define TCP_ECN_OK 1 |
| #define TCP_ECN_QUEUE_CWR 2 |
| #define TCP_ECN_DEMAND_CWR 4 |
| #define TCP_ECN_SEEN 8 |
| |
| enum tcp_tw_status { |
| TCP_TW_SUCCESS = 0, |
| TCP_TW_RST = 1, |
| TCP_TW_ACK = 2, |
| TCP_TW_SYN = 3 |
| }; |
| |
| |
| enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, |
| struct sk_buff *skb, |
| const struct tcphdr *th); |
| struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, |
| struct request_sock *req, struct request_sock **prev, |
| bool fastopen); |
| int tcp_child_process(struct sock *parent, struct sock *child, |
| struct sk_buff *skb); |
| void tcp_enter_loss(struct sock *sk); |
| void tcp_clear_retrans(struct tcp_sock *tp); |
| void tcp_update_metrics(struct sock *sk); |
| void tcp_init_metrics(struct sock *sk); |
| void tcp_metrics_init(void); |
| bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, |
| bool paws_check, bool timestamps); |
| bool tcp_remember_stamp(struct sock *sk); |
| bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw); |
| void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst); |
| void tcp_disable_fack(struct tcp_sock *tp); |
| void tcp_close(struct sock *sk, long timeout); |
| void tcp_init_sock(struct sock *sk); |
| unsigned int tcp_poll(struct file *file, struct socket *sock, |
| struct poll_table_struct *wait); |
| int tcp_getsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, int __user *optlen); |
| int tcp_setsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, unsigned int optlen); |
| int compat_tcp_getsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, int __user *optlen); |
| int compat_tcp_setsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, unsigned int optlen); |
| void tcp_set_keepalive(struct sock *sk, int val); |
| void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req); |
| int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, |
| size_t len, int nonblock, int flags, int *addr_len); |
| void tcp_parse_options(const struct sk_buff *skb, |
| struct tcp_options_received *opt_rx, |
| 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); |
| int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); |
| struct sock *tcp_create_openreq_child(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(struct sock *sk, struct sk_buff *skb, |
| struct request_sock *req, |
| struct dst_entry *dst); |
| 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); |
| struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, |
| struct request_sock *req, |
| struct tcp_fastopen_cookie *foc); |
| 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 */ |
| 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 |
| |
| static inline u32 tcp_cookie_time(void) |
| { |
| u64 val = get_jiffies_64(); |
| |
| do_div(val, 60 * HZ); |
| return val; |
| } |
| |
| u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, |
| u16 *mssp); |
| __u32 cookie_v4_init_sequence(struct sock *sk, 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(struct sock *sk, 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 *, struct sk_buff *); |
| int tcp_retransmit_skb(struct sock *, struct sk_buff *); |
| 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 *); |
| void tcp_send_fin(struct sock *sk); |
| void tcp_send_active_reset(struct sock *sk, gfp_t priority); |
| int tcp_send_synack(struct sock *); |
| bool tcp_syn_flood_action(struct sock *sk, const struct sk_buff *skb, |
| const char *proto); |
| 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); |
| |
| /* tcp_input.c */ |
| void tcp_resume_early_retransmit(struct sock *sk); |
| void tcp_rearm_rto(struct sock *sk); |
| void tcp_reset(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(const 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); |
| } |
| |
| /* 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 |
| |
| /* 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 is used in write queue only, |
| * cf tcp_skb_pcount() |
| */ |
| __u32 tcp_tw_isn; |
| __u32 tcp_gso_segs; |
| }; |
| __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 */ |
| /* 1 byte hole */ |
| __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 tcp_skb_pcount() > 1. */ |
| static inline int tcp_skb_mss(const struct sk_buff *skb) |
| { |
| return skb_shinfo(skb)->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 |
| |
| 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) */ |
| void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); |
| |
| 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); |
| #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) |
| { |
| tp->do_early_retrans = sysctl_tcp_early_retrans && |
| sysctl_tcp_early_retrans < 4 && !sysctl_tcp_thin_dupack && |
| 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_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; |
| } |
| |
| /* Slow start with delack produces 3 packets of burst, so that |
| * it is safe "de facto". This will be the default - same as |
| * the default reordering threshold - but if reordering increases, |
| * we must be able to allow cwnd to burst at least this much in order |
| * to not pull it back when holes are filled. |
| */ |
| static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) |
| { |
| return tp->reordering; |
| } |
| |
| /* 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 (tp->snd_cwnd <= tp->snd_ssthresh) |
| return tp->snd_cwnd < 2 * tp->max_packets_out; |
| |
| return tp->is_cwnd_limited; |
| } |
| |
| static inline void tcp_check_probe_timer(struct sock *sk) |
| { |
| const struct tcp_sock *tp = tcp_sk(sk); |
| const struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| if (!tp->packets_out && !icsk->icsk_pending) |
| inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, |
| icsk->icsk_rto, 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); |
| |
| 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); |
| |
| /* 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); |
| } |
| |
| static inline void tcp_openreq_init(struct request_sock *req, |
| struct tcp_options_received *rx_opt, |
| struct sk_buff *skb, struct sock *sk) |
| { |
| struct inet_request_sock *ireq = inet_rsk(req); |
| |
| req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
| req->cookie_ts = 0; |
| tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
| tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; |
| tcp_rsk(req)->snt_synack = tcp_time_stamp; |
| req->mss = rx_opt->mss_clamp; |
| req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; |
| ireq->tstamp_ok = rx_opt->tstamp_ok; |
| ireq->sack_ok = rx_opt->sack_ok; |
| ireq->snd_wscale = rx_opt->snd_wscale; |
| ireq->wscale_ok = rx_opt->wscale_ok; |
| ireq->acked = 0; |
| ireq->ecn_ok = 0; |
| ireq->ir_rmt_port = tcp_hdr(skb)->source; |
| ireq->ir_num = ntohs(tcp_hdr(skb)->dest); |
| ireq->ir_mark = inet_request_mark(sk, skb); |
| } |
| |
| extern void tcp_openreq_init_rwin(struct request_sock *req, |
| struct sock *sk, struct dst_entry *dst); |
| |
| void tcp_enter_memory_pressure(struct sock *sk); |
| |
| static inline int keepalive_intvl_when(const struct tcp_sock *tp) |
| { |
| return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; |
| } |
| |
| static inline int keepalive_time_when(const struct tcp_sock *tp) |
| { |
| return tp->keepalive_time ? : sysctl_tcp_keepalive_time; |
| } |
| |
| static inline int keepalive_probes(const struct tcp_sock *tp) |
| { |
| return tp->keepalive_probes ? : 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 ? : 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; |
| } |
| |
| 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; |
| } |
| |
| /* MD5 Signature */ |
| struct crypto_hash; |
| |
| 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 hash_desc md5_desc; |
| union tcp_md5sum_block md5_blk; |
| }; |
| |
| /* - functions */ |
| int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key, |
| const struct sock *sk, const struct request_sock *req, |
| 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(struct sock *sk, |
| struct sock *addr_sk); |
| |
| #ifdef CONFIG_TCP_MD5SIG |
| struct tcp_md5sig_key *tcp_md5_do_lookup(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(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); |
| 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); |
| bool 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; |
| } |
| |
| /* 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_OPENREQ, |
| 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; |
| kuid_t uid; |
| 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) |
| { |
| return tp->notsent_lowat ?: 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(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) (struct sock *sk, |
| struct sock *addr_sk); |
| int (*calc_md5_hash) (char *location, |
| struct tcp_md5sig_key *md5, |
| const struct sock *sk, |
| const struct request_sock *req, |
| 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 *(*md5_lookup) (struct sock *sk, |
| struct request_sock *req); |
| int (*calc_md5_hash) (char *location, |
| struct tcp_md5sig_key *md5, |
| const struct sock *sk, |
| const struct request_sock *req, |
| const struct sk_buff *skb); |
| #endif |
| void (*init_req)(struct request_sock *req, struct sock *sk, |
| struct sk_buff *skb); |
| #ifdef CONFIG_SYN_COOKIES |
| __u32 (*cookie_init_seq)(struct sock *sk, const struct sk_buff *skb, |
| __u16 *mss); |
| #endif |
| struct dst_entry *(*route_req)(struct sock *sk, struct flowi *fl, |
| const struct request_sock *req, |
| bool *strict); |
| __u32 (*init_seq)(const struct sk_buff *skb); |
| int (*send_synack)(struct sock *sk, struct dst_entry *dst, |
| struct flowi *fl, struct request_sock *req, |
| u16 queue_mapping, struct tcp_fastopen_cookie *foc); |
| void (*queue_hash_add)(struct sock *sk, struct request_sock *req, |
| const unsigned long timeout); |
| }; |
| |
| #ifdef CONFIG_SYN_COOKIES |
| static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, |
| struct sock *sk, struct sk_buff *skb, |
| __u16 *mss) |
| { |
| return ops->cookie_init_seq(sk, skb, mss); |
| } |
| #else |
| static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, |
| 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); |
| |
| /* |
| * 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; |
| } |
| |
| #endif /* _TCP_H */ |