SkidSec WebShell

Server Address : 172.31.38.4

Web Server : Apache/2.4.58 (Ubuntu)

Uname : Linux ip-172-31-38-4 6.14.0-1017-aws #17~24.04.1-Ubuntu SMP Wed Nov 5 10:48:17 UTC 2025 x86_64

PHP Version : 7.4.33

/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * 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> */ #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; } /** * skb_tcp_all_headers - Returns size of all headers for a TCP packet * @skb: buffer * * Used in TX path, for a packet known to be a TCP one. * * if (skb_is_gso(skb)) { * int hlen = skb_tcp_all_headers(skb); * ... */ static inline int skb_tcp_all_headers(const struct sk_buff *skb) { return skb_transport_offset(skb) + tcp_hdrlen(skb); } /** * skb_inner_tcp_all_headers - Returns size of all headers for an encap TCP packet * @skb: buffer * * Used in TX path, for a packet known to be a TCP one. * * if (skb_is_gso(skb) && skb->encapsulation) { * int hlen = skb_inner_tcp_all_headers(skb); * ... */ static inline int skb_inner_tcp_all_headers(const struct sk_buff *skb) { return skb_inner_transport_offset(skb) + inner_tcp_hdrlen(skb); } 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 { __le64 val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))]; s8 len; 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_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ struct tcp_options_received { /* PAWS/RTTM data */ int 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 : 3, /* SACK seen on SYN packet */ smc_ok : 1, /* SMC seen on SYN packet */ snd_wscale : 4, /* Window scaling received from sender */ rcv_wscale : 4; /* Window scaling to send to receiver */ u8 saw_unknown:1, /* Received unknown option */ unused:7; 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; #if IS_ENABLED(CONFIG_SMC) rx_opt->smc_ok = 0; #endif } /* 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; u64 snt_synack; /* first SYNACK sent time */ bool tfo_listener; bool is_mptcp; bool req_usec_ts; #if IS_ENABLED(CONFIG_MPTCP) bool drop_req; #endif u32 txhash; u32 rcv_isn; u32 snt_isn; u32 ts_off; u32 snt_tsval_first; u32 snt_tsval_last; u32 last_oow_ack_time; /* last SYNACK */ u32 rcv_nxt; /* the ack # by SYNACK. For * FastOpen it's the seq# * after data-in-SYN. */ u8 syn_tos; #ifdef CONFIG_TCP_AO u8 ao_keyid; u8 ao_rcv_next; bool used_tcp_ao; #endif }; static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) { return (struct tcp_request_sock *)req; } static inline bool tcp_rsk_used_ao(const struct request_sock *req) { #ifndef CONFIG_TCP_AO return false; #else return tcp_rsk(req)->used_tcp_ao; #endif } #define TCP_RMEM_TO_WIN_SCALE 8 struct tcp_sock { /* Cacheline organization can be found documented in * Documentation/networking/net_cachelines/tcp_sock.rst. * Please update the document when adding new fields. */ /* inet_connection_sock has to be the first member of tcp_sock */ struct inet_connection_sock inet_conn; /* TX read-mostly hotpath cache lines */ __cacheline_group_begin(tcp_sock_read_tx); u32 max_window; /* Maximal window ever seen from peer */ u32 rcv_ssthresh; /* Current window clamp */ u32 reordering; /* Packet reordering metric. */ u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */ u16 gso_segs; /* Max number of segs per GSO packet */ /* from STCP, retrans queue hinting */ struct sk_buff *lost_skb_hint; struct sk_buff *retransmit_skb_hint; __cacheline_group_end(tcp_sock_read_tx); /* TXRX read-mostly hotpath cache lines */ __cacheline_group_begin(tcp_sock_read_txrx); u32 tsoffset; /* timestamp offset */ u32 snd_wnd; /* The window we expect to receive */ u32 mss_cache; /* Cached effective mss, not including SACKS */ u32 snd_cwnd; /* Sending congestion window */ u32 prr_out; /* Total number of pkts sent during Recovery. */ u32 lost_out; /* Lost packets */ u32 sacked_out; /* SACK'd packets */ u16 tcp_header_len; /* Bytes of tcp header to send */ u8 scaling_ratio; /* see tcp_win_from_space() */ u8 chrono_type : 2, /* current chronograph type */ repair : 1, tcp_usec_ts : 1, /* TSval values in usec */ is_sack_reneg:1, /* in recovery from loss with SACK reneg? */ is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */ __cacheline_group_end(tcp_sock_read_txrx); /* RX read-mostly hotpath cache lines */ __cacheline_group_begin(tcp_sock_read_rx); u32 copied_seq; /* Head of yet unread data */ u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ u32 snd_wl1; /* Sequence for window update */ u32 tlp_high_seq; /* snd_nxt at the time of TLP */ u32 rttvar_us; /* smoothed mdev_max */ u32 retrans_out; /* Retransmitted packets out */ u16 advmss; /* Advertised MSS */ u16 urg_data; /* Saved octet of OOB data and control flags */ u32 lost; /* Total data packets lost incl. rexmits */ struct minmax rtt_min; /* OOO segments go in this rbtree. Socket lock must be held. */ struct rb_root out_of_order_queue; u32 snd_ssthresh; /* Slow start size threshold */ u8 recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */ __cacheline_group_end(tcp_sock_read_rx); /* TX read-write hotpath cache lines */ __cacheline_group_begin(tcp_sock_write_tx) ____cacheline_aligned; 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_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut * total number of data bytes sent. */ u32 snd_sml; /* Last byte of the most recently transmitted small packet */ u32 chrono_start; /* Start time in jiffies of a TCP chrono */ u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */ u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ u32 pushed_seq; /* Last pushed seq, required to talk to windows */ u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ u32 mdev_us; /* medium deviation */ u32 rtt_seq; /* sequence number to update rttvar */ u64 tcp_wstamp_ns; /* departure time for next sent data packet */ struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */ struct sk_buff *highest_sack; /* skb just after the highest * skb with SACKed bit set * (validity guaranteed only if * sacked_out > 0) */ u8 ecn_flags; /* ECN status bits. */ __cacheline_group_end(tcp_sock_write_tx); /* TXRX read-write hotpath cache lines */ __cacheline_group_begin(tcp_sock_write_txrx); /* * Header prediction flags * 0x5?10 << 16 + snd_wnd in net byte order */ __be32 pred_flags; u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */ u64 tcp_mstamp; /* most recent packet received/sent */ u32 rcv_nxt; /* What we want to receive next */ u32 snd_nxt; /* Next sequence we send */ u32 snd_una; /* First byte we want an ack for */ u32 window_clamp; /* Maximal window to advertise */ u32 srtt_us; /* smoothed round trip time << 3 in usecs */ u32 packets_out; /* Packets which are "in flight" */ u32 snd_up; /* Urgent pointer */ u32 delivered; /* Total data packets delivered incl. rexmits */ u32 delivered_ce; /* Like the above but only ECE marked packets */ u32 app_limited; /* limited until "delivered" reaches this val */ u32 rcv_wnd; /* Current receiver window */ /* * Options received (usually on last packet, some only on SYN packets). */ struct tcp_options_received rx_opt; u8 nonagle : 4,/* Disable Nagle algorithm? */ rate_app_limited:1; /* rate_{delivered,interval_us} limited? */ __cacheline_group_end(tcp_sock_write_txrx); /* RX read-write hotpath cache lines */ __cacheline_group_begin(tcp_sock_write_rx) __aligned(8); 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_wup; /* rcv_nxt on last window update sent */ u32 max_packets_out; /* max packets_out in last window */ u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */ u32 rate_delivered; /* saved rate sample: packets delivered */ u32 rate_interval_us; /* saved rate sample: time elapsed */ u32 rcv_rtt_last_tsecr; u64 first_tx_mstamp; /* start of window send phase */ u64 delivered_mstamp; /* time we reached "delivered" */ u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked * sum(delta(snd_una)), or how many bytes * were acked. */ struct { u32 rtt_us; u32 seq; u64 time; } rcv_rtt_est; /* Receiver queue space */ struct { int space; u32 seq; u64 time; } rcvq_space; __cacheline_group_end(tcp_sock_write_rx); /* End of Hot Path */ /* * 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 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups * total number of DSACK blocks received */ u32 compressed_ack_rcv_nxt; struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ /* Information of the most recently (s)acked skb */ struct tcp_rack { u64 mstamp; /* (Re)sent time of the skb */ u32 rtt_us; /* Associated RTT */ u32 end_seq; /* Ending TCP sequence of the skb */ u32 last_delivered; /* tp->delivered at last reo_wnd adj */ u8 reo_wnd_steps; /* Allowed reordering window */ #define TCP_RACK_RECOVERY_THRESH 16 u8 reo_wnd_persist:5, /* No. of recovery since last adj */ dsack_seen:1, /* Whether DSACK seen after last adj */ advanced:1; /* mstamp advanced since last lost marking */ } rack; u8 compressed_ack; u8 dup_ack_counter:2, tlp_retrans:1, /* TLP is a retransmission */ unused:5; u8 thin_lto : 1,/* Use linear timeouts for thin streams */ fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */ fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */ fastopen_client_fail:2, /* reason why fastopen failed */ frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */ u8 repair_queue; u8 save_syn:2, /* Save headers of SYN packet */ 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_fastopen_ch:1, /* Active TFO re-enabling probe */ syn_data_acked:1;/* data in SYN is acked by SYN-ACK */ u8 keepalive_probes; /* num of allowed keep alive probes */ u32 tcp_tx_delay; /* delay (in usec) added to TX packets */ /* RTT measurement */ u32 mdev_max_us; /* maximal mdev for the last rtt period */ u32 reord_seen; /* number of data packet reordering events */ /* * Slow start and congestion control (see also Nagle, and Karn & Partridge) */ 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; /* cwnd right before starting loss recovery */ u32 prr_delivered; /* Number of newly delivered packets to * receiver in Recovery. */ u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */ struct hrtimer pacing_timer; struct hrtimer compressed_ack_timer; 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]; int lost_cnt_hint; 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. */ u64 bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans * Total data bytes retransmitted */ u32 total_retrans; /* Total retransmits for entire connection */ u32 rto_stamp; /* Start time (ms) of last CA_Loss recovery */ u16 total_rto; /* Total number of RTO timeouts, including * SYN/SYN-ACK and recurring timeouts. */ u16 total_rto_recoveries; /* Total number of RTO recoveries, * including any unfinished recovery. */ u32 total_rto_time; /* ms spent in (completed) RTO recoveries. */ 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; /* Sock_ops bpf program related variables */ #ifdef CONFIG_BPF u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs * values defined in uapi/linux/tcp.h */ u8 bpf_chg_cc_inprogress:1; /* In the middle of * bpf_setsockopt(TCP_CONGESTION), * it is to avoid the bpf_tcp_cc->init() * to recur itself by calling * bpf_setsockopt(TCP_CONGESTION, "itself"). */ #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG) #else #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0 #endif u16 timeout_rehash; /* Timeout-triggered rehash attempts */ u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */ /* TCP-specific MTU probe information. */ struct { u32 probe_seq_start; u32 probe_seq_end; } mtu_probe; u32 plb_rehash; /* PLB-triggered rehash attempts */ u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG * while socket was owned by user. */ #if IS_ENABLED(CONFIG_MPTCP) bool is_mptcp; #endif #if IS_ENABLED(CONFIG_SMC) bool syn_smc; /* SYN includes SMC */ bool (*smc_hs_congested)(const struct sock *sk); #endif #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) /* TCP AF-Specific parts; only used by TCP-AO/MD5 Signature support so far */ const struct tcp_sock_af_ops *af_specific; #ifdef CONFIG_TCP_MD5SIG /* TCP MD5 Signature Option information */ struct tcp_md5sig_info __rcu *md5sig_info; #endif #ifdef CONFIG_TCP_AO struct tcp_ao_info __rcu *ao_info; #endif #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 __rcu *fastopen_rsk; struct saved_syn *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() */ TCP_ACK_DEFERRED, /* TX pure ack is deferred */ }; enum tsq_flags { TSQF_THROTTLED = BIT(TSQ_THROTTLED), TSQF_QUEUED = BIT(TSQ_QUEUED), TCPF_TSQ_DEFERRED = BIT(TCP_TSQ_DEFERRED), TCPF_WRITE_TIMER_DEFERRED = BIT(TCP_WRITE_TIMER_DEFERRED), TCPF_DELACK_TIMER_DEFERRED = BIT(TCP_DELACK_TIMER_DEFERRED), TCPF_MTU_REDUCED_DEFERRED = BIT(TCP_MTU_REDUCED_DEFERRED), TCPF_ACK_DEFERRED = BIT(TCP_ACK_DEFERRED), }; #define tcp_sk(ptr) container_of_const(ptr, struct tcp_sock, inet_conn.icsk_inet.sk) /* Variant of tcp_sk() upgrading a const sock to a read/write tcp socket. * Used in context of (lockless) tcp listeners. */ #define tcp_sk_rw(ptr) container_of(ptr, struct tcp_sock, inet_conn.icsk_inet.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; int tw_ts_recent_stamp; u32 tw_tx_delay; #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *tw_md5_key; #endif #ifdef CONFIG_TCP_AO struct tcp_ao_info __rcu *ao_info; #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 && rcu_access_pointer(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); WRITE_ONCE(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; } static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn) { return saved_syn->mac_hdrlen + saved_syn->network_hdrlen + saved_syn->tcp_hdrlen; } struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, const struct sk_buff *orig_skb, const struct sk_buff *ack_skb); static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss) { /* We use READ_ONCE() here because socket might not be locked. * This happens for listeners. */ u16 user_mss = READ_ONCE(tp->rx_opt.user_mss); return (user_mss && user_mss < mss) ? user_mss : mss; } int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount, int shiftlen); void __tcp_sock_set_cork(struct sock *sk, bool on); void tcp_sock_set_cork(struct sock *sk, bool on); int tcp_sock_set_keepcnt(struct sock *sk, int val); int tcp_sock_set_keepidle_locked(struct sock *sk, int val); int tcp_sock_set_keepidle(struct sock *sk, int val); int tcp_sock_set_keepintvl(struct sock *sk, int val); void __tcp_sock_set_nodelay(struct sock *sk, bool on); void tcp_sock_set_nodelay(struct sock *sk); void tcp_sock_set_quickack(struct sock *sk, int val); int tcp_sock_set_syncnt(struct sock *sk, int val); int tcp_sock_set_user_timeout(struct sock *sk, int val); static inline bool dst_tcp_usec_ts(const struct dst_entry *dst) { return dst_feature(dst, RTAX_FEATURE_TCP_USEC_TS); } #endif /* _LINUX_TCP_H */