443 lines
14 KiB
C
443 lines
14 KiB
C
/*
|
|
* 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, <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 _LINUX_TCP_H
|
|
#define _LINUX_TCP_H
|
|
|
|
|
|
#include <linux/skbuff.h>
|
|
#include <linux/win_minmax.h>
|
|
#include <net/sock.h>
|
|
#include <net/inet_connection_sock.h>
|
|
#include <net/inet_timewait_sock.h>
|
|
#include <uapi/linux/tcp.h>
|
|
|
|
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 tcphdr *th)
|
|
{
|
|
return th->doff * 4;
|
|
}
|
|
|
|
static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
|
|
{
|
|
return __tcp_hdrlen(tcp_hdr(skb));
|
|
}
|
|
|
|
static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb)
|
|
{
|
|
return (struct tcphdr *)skb_inner_transport_header(skb);
|
|
}
|
|
|
|
static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb)
|
|
{
|
|
return inner_tcp_hdr(skb)->doff * 4;
|
|
}
|
|
|
|
static inline unsigned int tcp_optlen(const struct sk_buff *skb)
|
|
{
|
|
return (tcp_hdr(skb)->doff - 5) * 4;
|
|
}
|
|
|
|
/* TCP Fast Open */
|
|
#define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */
|
|
#define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */
|
|
#define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */
|
|
|
|
/* TCP Fast Open Cookie as stored in memory */
|
|
struct tcp_fastopen_cookie {
|
|
s8 len;
|
|
u8 val[TCP_FASTOPEN_COOKIE_MAX];
|
|
bool exp; /* In RFC6994 experimental option format */
|
|
};
|
|
|
|
/* 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 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;
|
|
}
|
|
|
|
/* 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_request_sock_ops;
|
|
|
|
struct tcp_request_sock {
|
|
struct inet_request_sock req;
|
|
const struct tcp_request_sock_ops *af_specific;
|
|
struct skb_mstamp snt_synack; /* first SYNACK sent time */
|
|
bool tfo_listener;
|
|
u32 txhash;
|
|
u32 rcv_isn;
|
|
u32 snt_isn;
|
|
u32 ts_off;
|
|
u32 last_oow_ack_time; /* last SYNACK */
|
|
u32 rcv_nxt; /* the ack # by SYNACK. For
|
|
* FastOpen it's the seq#
|
|
* after data-in-SYN.
|
|
*/
|
|
};
|
|
|
|
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 gso_segs; /* Max number of segs per GSO packet */
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
|
|
* sum(delta(rcv_nxt)), or how many bytes
|
|
* were acked.
|
|
*/
|
|
u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
|
|
* total number of segments in.
|
|
*/
|
|
u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
|
|
* total number of data segments in.
|
|
*/
|
|
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 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
|
|
* The total number of segments sent.
|
|
*/
|
|
u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
|
|
* total number of data segments sent.
|
|
*/
|
|
u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
|
|
* sum(delta(snd_una)), or how many bytes
|
|
* were acked.
|
|
*/
|
|
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) */
|
|
u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */
|
|
|
|
u32 tsoffset; /* timestamp offset */
|
|
|
|
struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
|
|
|
|
/* Data for direct copy to user */
|
|
struct {
|
|
struct sk_buff_head prequeue;
|
|
struct task_struct *task;
|
|
struct msghdr *msg;
|
|
int memory;
|
|
int len;
|
|
} 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 */
|
|
|
|
/* Information of the most recently (s)acked skb */
|
|
struct tcp_rack {
|
|
struct skb_mstamp mstamp; /* (Re)sent time of the skb */
|
|
u8 advanced; /* mstamp advanced since last lost marking */
|
|
u8 reord; /* reordering detected */
|
|
} rack;
|
|
u16 advmss; /* Advertised MSS */
|
|
u32 chrono_start; /* Start time in jiffies of a TCP chrono */
|
|
u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */
|
|
u8 chrono_type:2, /* current chronograph type */
|
|
rate_app_limited:1, /* rate_{delivered,interval_us} limited? */
|
|
unused:5;
|
|
u8 nonagle : 4,/* Disable Nagle algorithm? */
|
|
thin_lto : 1,/* Use linear timeouts for thin streams */
|
|
thin_dupack : 1,/* Fast retransmit on first dupack */
|
|
repair : 1,
|
|
frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */
|
|
u8 repair_queue;
|
|
u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */
|
|
syn_data:1, /* SYN includes data */
|
|
syn_fastopen:1, /* SYN includes Fast Open option */
|
|
syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
|
|
syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
|
|
save_syn:1, /* Save headers of SYN packet */
|
|
is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
|
|
u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */
|
|
|
|
/* RTT measurement */
|
|
u32 srtt_us; /* smoothed round trip time << 3 in usecs */
|
|
u32 mdev_us; /* medium deviation */
|
|
u32 mdev_max_us; /* maximal mdev for the last rtt period */
|
|
u32 rttvar_us; /* smoothed mdev_max */
|
|
u32 rtt_seq; /* sequence number to update rttvar */
|
|
struct minmax rtt_min;
|
|
|
|
u32 packets_out; /* Packets which are "in flight" */
|
|
u32 retrans_out; /* Retransmitted packets out */
|
|
u32 max_packets_out; /* max packets_out in last window */
|
|
u32 max_packets_seq; /* right edge of max_packets_out flight */
|
|
|
|
u16 urg_data; /* Saved octet of OOB data and control flags */
|
|
u8 ecn_flags; /* ECN status bits. */
|
|
u8 keepalive_probes; /* num of allowed keep alive probes */
|
|
u32 reordering; /* Packet reordering metric. */
|
|
u32 snd_up; /* Urgent pointer */
|
|
|
|
/*
|
|
* 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 delivered; /* Total data packets delivered incl. rexmits */
|
|
u32 lost; /* Total data packets lost incl. rexmits */
|
|
u32 app_limited; /* limited until "delivered" reaches this val */
|
|
struct skb_mstamp first_tx_mstamp; /* start of window send phase */
|
|
struct skb_mstamp delivered_mstamp; /* time we reached "delivered" */
|
|
u32 rate_delivered; /* saved rate sample: packets delivered */
|
|
u32 rate_interval_us; /* saved rate sample: time elapsed */
|
|
|
|
u32 rcv_wnd; /* Current receiver window */
|
|
u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
|
|
u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */
|
|
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 */
|
|
|
|
/* from STCP, retrans queue hinting */
|
|
struct sk_buff* lost_skb_hint;
|
|
struct sk_buff *retransmit_skb_hint;
|
|
|
|
/* OOO segments go in this rbtree. Socket lock must be held. */
|
|
struct rb_root out_of_order_queue;
|
|
struct sk_buff *ooo_last_skb; /* cache rb_last(out_of_order_queue) */
|
|
|
|
/* SACKs data, these 2 need to be together (see tcp_options_write) */
|
|
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 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; /* snd_una upon a new recovery episode. */
|
|
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;
|
|
u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
|
|
* while socket was owned by user.
|
|
*/
|
|
|
|
#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
|
|
|
|
/* TCP fastopen related information */
|
|
struct tcp_fastopen_request *fastopen_req;
|
|
/* fastopen_rsk points to request_sock that resulted in this big
|
|
* socket. Used to retransmit SYNACKs etc.
|
|
*/
|
|
struct request_sock *fastopen_rsk;
|
|
u32 *saved_syn;
|
|
};
|
|
|
|
enum tsq_enum {
|
|
TSQ_THROTTLED,
|
|
TSQ_QUEUED,
|
|
TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */
|
|
TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */
|
|
TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */
|
|
TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call
|
|
* tcp_v{4|6}_mtu_reduced()
|
|
*/
|
|
};
|
|
|
|
enum tsq_flags {
|
|
TSQF_THROTTLED = (1UL << TSQ_THROTTLED),
|
|
TSQF_QUEUED = (1UL << TSQ_QUEUED),
|
|
TCPF_TSQ_DEFERRED = (1UL << TCP_TSQ_DEFERRED),
|
|
TCPF_WRITE_TIMER_DEFERRED = (1UL << TCP_WRITE_TIMER_DEFERRED),
|
|
TCPF_DELACK_TIMER_DEFERRED = (1UL << TCP_DELACK_TIMER_DEFERRED),
|
|
TCPF_MTU_REDUCED_DEFERRED = (1UL << TCP_MTU_REDUCED_DEFERRED),
|
|
};
|
|
|
|
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;
|
|
#define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt
|
|
#define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt
|
|
u32 tw_rcv_wnd;
|
|
u32 tw_ts_offset;
|
|
u32 tw_ts_recent;
|
|
|
|
/* The time we sent the last out-of-window ACK: */
|
|
u32 tw_last_oow_ack_time;
|
|
|
|
long tw_ts_recent_stamp;
|
|
#ifdef CONFIG_TCP_MD5SIG
|
|
struct tcp_md5sig_key *tw_md5_key;
|
|
#endif
|
|
};
|
|
|
|
static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
|
|
{
|
|
return (struct tcp_timewait_sock *)sk;
|
|
}
|
|
|
|
static inline bool tcp_passive_fastopen(const struct sock *sk)
|
|
{
|
|
return (sk->sk_state == TCP_SYN_RECV &&
|
|
tcp_sk(sk)->fastopen_rsk != NULL);
|
|
}
|
|
|
|
static inline void fastopen_queue_tune(struct sock *sk, int backlog)
|
|
{
|
|
struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
|
|
int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn);
|
|
|
|
queue->fastopenq.max_qlen = min_t(unsigned int, backlog, somaxconn);
|
|
}
|
|
|
|
static inline void tcp_move_syn(struct tcp_sock *tp,
|
|
struct request_sock *req)
|
|
{
|
|
tp->saved_syn = req->saved_syn;
|
|
req->saved_syn = NULL;
|
|
}
|
|
|
|
static inline void tcp_saved_syn_free(struct tcp_sock *tp)
|
|
{
|
|
kfree(tp->saved_syn);
|
|
tp->saved_syn = NULL;
|
|
}
|
|
|
|
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk);
|
|
|
|
#endif /* _LINUX_TCP_H */
|