/* * 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 protocol. * * Version: @(#)tcp.h 1.0.2 04/28/93 * * Author: Fred N. van Kempen, * * 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 _LINUX_TCP_H #define _LINUX_TCP_H #include #include #include struct tcphdr { __be16 source; __be16 dest; __be32 seq; __be32 ack_seq; #if defined(__LITTLE_ENDIAN_BITFIELD) __u16 res1:4, doff:4, fin:1, syn:1, rst:1, psh:1, ack:1, urg:1, ece:1, cwr:1; #elif defined(__BIG_ENDIAN_BITFIELD) __u16 doff:4, res1:4, cwr:1, ece:1, urg:1, ack:1, psh:1, rst:1, syn:1, fin:1; #else #error "Adjust your defines" #endif __be16 window; __sum16 check; __be16 urg_ptr; }; /* * The union cast uses a gcc extension to avoid aliasing problems * (union is compatible to any of its members) * This means this part of the code is -fstrict-aliasing safe now. */ union tcp_word_hdr { struct tcphdr hdr; __be32 words[5]; }; #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) enum { TCP_FLAG_CWR = __cpu_to_be32(0x00800000), TCP_FLAG_ECE = __cpu_to_be32(0x00400000), TCP_FLAG_URG = __cpu_to_be32(0x00200000), TCP_FLAG_ACK = __cpu_to_be32(0x00100000), TCP_FLAG_PSH = __cpu_to_be32(0x00080000), TCP_FLAG_RST = __cpu_to_be32(0x00040000), TCP_FLAG_SYN = __cpu_to_be32(0x00020000), TCP_FLAG_FIN = __cpu_to_be32(0x00010000), TCP_RESERVED_BITS = __cpu_to_be32(0x0F000000), TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000) }; /* * TCP general constants */ #define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */ #define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */ /* TCP socket options */ #define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */ #define TCP_MAXSEG 2 /* Limit MSS */ #define TCP_CORK 3 /* Never send partially complete segments */ #define TCP_KEEPIDLE 4 /* Start keeplives after this period */ #define TCP_KEEPINTVL 5 /* Interval between keepalives */ #define TCP_KEEPCNT 6 /* Number of keepalives before death */ #define TCP_SYNCNT 7 /* Number of SYN retransmits */ #define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */ #define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */ #define TCP_WINDOW_CLAMP 10 /* Bound advertised window */ #define TCP_INFO 11 /* Information about this connection. */ #define TCP_QUICKACK 12 /* Block/reenable quick acks */ #define TCP_CONGESTION 13 /* Congestion control algorithm */ #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ #define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */ #define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ #define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ #define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */ /* for TCP_INFO socket option */ #define TCPI_OPT_TIMESTAMPS 1 #define TCPI_OPT_SACK 2 #define TCPI_OPT_WSCALE 4 #define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */ #define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */ enum tcp_ca_state { TCP_CA_Open = 0, #define TCPF_CA_Open (1< #include #include #include #include static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) { return (struct tcphdr *)skb_transport_header(skb); } static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) { return tcp_hdr(skb)->doff * 4; } static inline unsigned int tcp_optlen(const struct sk_buff *skb) { return (tcp_hdr(skb)->doff - 5) * 4; } /* This defines a selective acknowledgement block. */ struct tcp_sack_block_wire { __be32 start_seq; __be32 end_seq; }; struct tcp_sack_block { u32 start_seq; u32 end_seq; }; /*These are used to set the sack_ok field in struct tcp_options_received */ #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ #define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/ #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ struct tcp_options_received { /* PAWS/RTTM data */ long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ u32 ts_recent; /* Time stamp to echo next */ u32 rcv_tsval; /* Time stamp value */ u32 rcv_tsecr; /* Time stamp echo reply */ u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ dsack : 1, /* D-SACK is scheduled */ wscale_ok : 1, /* Wscale seen on SYN packet */ sack_ok : 4, /* SACK seen on SYN packet */ snd_wscale : 4, /* Window scaling received from sender */ rcv_wscale : 4; /* Window scaling to send to receiver */ u8 cookie_plus:6, /* bytes in authenticator/cookie option */ cookie_out_never:1, cookie_in_always:1; u8 num_sacks; /* Number of SACK blocks */ u16 user_mss; /* mss requested by user in ioctl */ u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ }; static inline void tcp_clear_options(struct tcp_options_received *rx_opt) { rx_opt->tstamp_ok = rx_opt->sack_ok = 0; rx_opt->wscale_ok = rx_opt->snd_wscale = 0; rx_opt->cookie_plus = 0; } /* This is the max number of SACKS that we'll generate and process. It's safe * to increase this, although since: * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) * only four options will fit in a standard TCP header */ #define TCP_NUM_SACKS 4 struct tcp_cookie_values; struct tcp_request_sock_ops; struct tcp_request_sock { struct inet_request_sock req; #ifdef CONFIG_TCP_MD5SIG /* Only used by TCP MD5 Signature so far. */ const struct tcp_request_sock_ops *af_specific; #endif u32 rcv_isn; u32 snt_isn; u32 snt_synack; /* synack sent time */ }; static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) { return (struct tcp_request_sock *)req; } struct tcp_sock { /* inet_connection_sock has to be the first member of tcp_sock */ struct inet_connection_sock inet_conn; u16 tcp_header_len; /* Bytes of tcp header to send */ u16 xmit_size_goal_segs; /* Goal for segmenting output packets */ /* * Header prediction flags * 0x5?10 << 16 + snd_wnd in net byte order */ __be32 pred_flags; /* * RFC793 variables by their proper names. This means you can * read the code and the spec side by side (and laugh ...) * See RFC793 and RFC1122. The RFC writes these in capitals. */ u32 rcv_nxt; /* What we want to receive next */ u32 copied_seq; /* Head of yet unread data */ u32 rcv_wup; /* rcv_nxt on last window update sent */ u32 snd_nxt; /* Next sequence we send */ u32 snd_una; /* First byte we want an ack for */ u32 snd_sml; /* Last byte of the most recently transmitted small packet */ u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ /* Data for direct copy to user */ struct { struct sk_buff_head prequeue; struct task_struct *task; struct iovec *iov; int memory; int len; #ifdef CONFIG_NET_DMA /* members for async copy */ struct dma_chan *dma_chan; int wakeup; struct dma_pinned_list *pinned_list; dma_cookie_t dma_cookie; #endif } ucopy; u32 snd_wl1; /* Sequence for window update */ u32 snd_wnd; /* The window we expect to receive */ u32 max_window; /* Maximal window ever seen from peer */ u32 mss_cache; /* Cached effective mss, not including SACKS */ u32 window_clamp; /* Maximal window to advertise */ u32 rcv_ssthresh; /* Current window clamp */ u32 frto_highmark; /* snd_nxt when RTO occurred */ u16 advmss; /* Advertised MSS */ u8 frto_counter; /* Number of new acks after RTO */ u8 nonagle : 4,/* Disable Nagle algorithm? */ thin_lto : 1,/* Use linear timeouts for thin streams */ thin_dupack : 1,/* Fast retransmit on first dupack */ unused : 2; /* RTT measurement */ u32 srtt; /* smoothed round trip time << 3 */ u32 mdev; /* medium deviation */ u32 mdev_max; /* maximal mdev for the last rtt period */ u32 rttvar; /* smoothed mdev_max */ u32 rtt_seq; /* sequence number to update rttvar */ u32 packets_out; /* Packets which are "in flight" */ u32 retrans_out; /* Retransmitted packets out */ u16 urg_data; /* Saved octet of OOB data and control flags */ u8 ecn_flags; /* ECN status bits. */ u8 reordering; /* Packet reordering metric. */ u32 snd_up; /* Urgent pointer */ u8 keepalive_probes; /* num of allowed keep alive probes */ /* * Options received (usually on last packet, some only on SYN packets). */ struct tcp_options_received rx_opt; /* * Slow start and congestion control (see also Nagle, and Karn & Partridge) */ u32 snd_ssthresh; /* Slow start size threshold */ u32 snd_cwnd; /* Sending congestion window */ u32 snd_cwnd_cnt; /* Linear increase counter */ u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ u32 snd_cwnd_used; u32 snd_cwnd_stamp; u32 prior_cwnd; /* Congestion window at start of Recovery. */ u32 prr_delivered; /* Number of newly delivered packets to * receiver in Recovery. */ u32 prr_out; /* Total number of pkts sent during Recovery. */ u32 rcv_wnd; /* Current receiver window */ u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ u32 pushed_seq; /* Last pushed seq, required to talk to windows */ u32 lost_out; /* Lost packets */ u32 sacked_out; /* SACK'd packets */ u32 fackets_out; /* FACK'd packets */ u32 tso_deferred; u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */ /* from STCP, retrans queue hinting */ struct sk_buff* lost_skb_hint; struct sk_buff *scoreboard_skb_hint; struct sk_buff *retransmit_skb_hint; struct sk_buff_head out_of_order_queue; /* Out of order segments go here */ /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */ struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ struct tcp_sack_block recv_sack_cache[4]; struct sk_buff *highest_sack; /* skb just after the highest * skb with SACKed bit set * (validity guaranteed only if * sacked_out > 0) */ int lost_cnt_hint; u32 retransmit_high; /* L-bits may be on up to this seqno */ u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ u32 prior_ssthresh; /* ssthresh saved at recovery start */ u32 high_seq; /* snd_nxt at onset of congestion */ u32 retrans_stamp; /* Timestamp of the last retransmit, * also used in SYN-SENT to remember stamp of * the first SYN. */ u32 undo_marker; /* tracking retrans started here. */ int undo_retrans; /* number of undoable retransmissions. */ u32 total_retrans; /* Total retransmits for entire connection */ u32 urg_seq; /* Seq of received urgent pointer */ unsigned int keepalive_time; /* time before keep alive takes place */ unsigned int keepalive_intvl; /* time interval between keep alive probes */ int linger2; /* Receiver side RTT estimation */ struct { u32 rtt; u32 seq; u32 time; } rcv_rtt_est; /* Receiver queue space */ struct { int space; u32 seq; u32 time; } rcvq_space; /* TCP-specific MTU probe information. */ struct { u32 probe_seq_start; u32 probe_seq_end; } mtu_probe; #ifdef CONFIG_TCP_MD5SIG /* TCP AF-Specific parts; only used by MD5 Signature support so far */ const struct tcp_sock_af_ops *af_specific; /* TCP MD5 Signature Option information */ struct tcp_md5sig_info __rcu *md5sig_info; #endif /* When the cookie options are generated and exchanged, then this * object holds a reference to them (cookie_values->kref). Also * contains related tcp_cookie_transactions fields. */ struct tcp_cookie_values *cookie_values; }; static inline struct tcp_sock *tcp_sk(const struct sock *sk) { return (struct tcp_sock *)sk; } struct tcp_timewait_sock { struct inet_timewait_sock tw_sk; u32 tw_rcv_nxt; u32 tw_snd_nxt; u32 tw_rcv_wnd; u32 tw_ts_recent; long tw_ts_recent_stamp; #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *tw_md5_key; #endif /* Few sockets in timewait have cookies; in that case, then this * object holds a reference to them (tw_cookie_values->kref). */ struct tcp_cookie_values *tw_cookie_values; }; static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) { return (struct tcp_timewait_sock *)sk; } #endif /* __KERNEL__ */ #endif /* _LINUX_TCP_H */