The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_var.h

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1993, 1994, 1995
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)tcp_var.h   8.4 (Berkeley) 5/24/95
   30  * $FreeBSD$
   31  */
   32 
   33 #ifndef _NETINET_TCP_VAR_H_
   34 #define _NETINET_TCP_VAR_H_
   35 
   36 #include <netinet/tcp.h>
   37 
   38 #ifdef _KERNEL
   39 #include <net/vnet.h>
   40 
   41 /*
   42  * Kernel variables for tcp.
   43  */
   44 VNET_DECLARE(int, tcp_do_rfc1323);
   45 #define V_tcp_do_rfc1323        VNET(tcp_do_rfc1323)
   46 
   47 #endif /* _KERNEL */
   48 
   49 /* TCP segment queue entry */
   50 struct tseg_qent {
   51         LIST_ENTRY(tseg_qent) tqe_q;
   52         int     tqe_len;                /* TCP segment data length */
   53         struct  tcphdr *tqe_th;         /* a pointer to tcp header */
   54         struct  mbuf    *tqe_m;         /* mbuf contains packet */
   55 };
   56 LIST_HEAD(tsegqe_head, tseg_qent);
   57 
   58 struct sackblk {
   59         tcp_seq start;          /* start seq no. of sack block */
   60         tcp_seq end;            /* end seq no. */
   61 };
   62 
   63 struct sackhole {
   64         tcp_seq start;          /* start seq no. of hole */
   65         tcp_seq end;            /* end seq no. */
   66         tcp_seq rxmit;          /* next seq. no in hole to be retransmitted */
   67         TAILQ_ENTRY(sackhole) scblink;  /* scoreboard linkage */
   68 };
   69 
   70 struct sackhint {
   71         struct sackhole *nexthole;
   72         int             sack_bytes_rexmit;
   73         tcp_seq         last_sack_ack;  /* Most recent/largest sacked ack */
   74 
   75         int             ispare;         /* explicit pad for 64bit alignment */
   76         int             sacked_bytes;   /*
   77                                          * Total sacked bytes reported by the
   78                                          * receiver via sack option
   79                                          */
   80         uint32_t        _pad1[1];       /* TBD */
   81         uint64_t        _pad[1];        /* TBD */
   82 };
   83 
   84 struct tcptemp {
   85         u_char  tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
   86         struct  tcphdr tt_t;
   87 };
   88 
   89 #define tcp6cb          tcpcb  /* for KAME src sync over BSD*'s */
   90 
   91 /* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
   92 #ifdef INET6
   93 #define ND6_HINT(tp)                                            \
   94 do {                                                            \
   95         if ((tp) && (tp)->t_inpcb &&                            \
   96             ((tp)->t_inpcb->inp_vflag & INP_IPV6) != 0)         \
   97                 nd6_nud_hint(NULL, NULL, 0);                    \
   98 } while (0)
   99 #else
  100 #define ND6_HINT(tp)
  101 #endif
  102 
  103 /*
  104  * Tcp control block, one per tcp; fields:
  105  * Organized for 16 byte cacheline efficiency.
  106  */
  107 struct tcpcb {
  108         struct  tsegqe_head t_segq;     /* segment reassembly queue */
  109         void    *t_pspare[2];           /* new reassembly queue */
  110         int     t_segqlen;              /* segment reassembly queue length */
  111         int     t_dupacks;              /* consecutive dup acks recd */
  112 
  113         struct tcp_timer *t_timers;     /* All the TCP timers in one struct */
  114 
  115         struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
  116         int     t_state;                /* state of this connection */
  117         u_int   t_flags;
  118 
  119         struct  vnet *t_vnet;           /* back pointer to parent vnet */
  120 
  121         tcp_seq snd_una;                /* send unacknowledged */
  122         tcp_seq snd_max;                /* highest sequence number sent;
  123                                          * used to recognize retransmits
  124                                          */
  125         tcp_seq snd_nxt;                /* send next */
  126         tcp_seq snd_up;                 /* send urgent pointer */
  127 
  128         tcp_seq snd_wl1;                /* window update seg seq number */
  129         tcp_seq snd_wl2;                /* window update seg ack number */
  130         tcp_seq iss;                    /* initial send sequence number */
  131         tcp_seq irs;                    /* initial receive sequence number */
  132 
  133         tcp_seq rcv_nxt;                /* receive next */
  134         tcp_seq rcv_adv;                /* advertised window */
  135         u_long  rcv_wnd;                /* receive window */
  136         tcp_seq rcv_up;                 /* receive urgent pointer */
  137 
  138         u_long  snd_wnd;                /* send window */
  139         u_long  snd_cwnd;               /* congestion-controlled window */
  140         u_long  snd_spare1;             /* unused */
  141         u_long  snd_ssthresh;           /* snd_cwnd size threshold for
  142                                          * for slow start exponential to
  143                                          * linear switch
  144                                          */
  145         u_long  snd_spare2;             /* unused */
  146         tcp_seq snd_recover;            /* for use in NewReno Fast Recovery */
  147 
  148         u_int   t_maxopd;               /* mss plus options */
  149 
  150         u_int   t_rcvtime;              /* inactivity time */
  151         u_int   t_starttime;            /* time connection was established */
  152         u_int   t_rtttime;              /* RTT measurement start time */
  153         tcp_seq t_rtseq;                /* sequence number being timed */
  154 
  155         u_int   t_bw_spare1;            /* unused */
  156         tcp_seq t_bw_spare2;            /* unused */
  157 
  158         int     t_rxtcur;               /* current retransmit value (ticks) */
  159         u_int   t_maxseg;               /* maximum segment size */
  160         int     t_srtt;                 /* smoothed round-trip time */
  161         int     t_rttvar;               /* variance in round-trip time */
  162 
  163         int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
  164         u_int   t_rttmin;               /* minimum rtt allowed */
  165         u_int   t_rttbest;              /* best rtt we've seen */
  166         u_long  t_rttupdated;           /* number of times rtt sampled */
  167         u_long  max_sndwnd;             /* largest window peer has offered */
  168 
  169         int     t_softerror;            /* possible error not yet reported */
  170 /* out-of-band data */
  171         char    t_oobflags;             /* have some */
  172         char    t_iobc;                 /* input character */
  173 /* RFC 1323 variables */
  174         u_char  snd_scale;              /* window scaling for send window */
  175         u_char  rcv_scale;              /* window scaling for recv window */
  176         u_char  request_r_scale;        /* pending window scaling */
  177         u_int32_t  ts_recent;           /* timestamp echo data */
  178         u_int   ts_recent_age;          /* when last updated */
  179         u_int32_t  ts_offset;           /* our timestamp offset */
  180 
  181         tcp_seq last_ack_sent;
  182 /* experimental */
  183         u_long  snd_cwnd_prev;          /* cwnd prior to retransmit */
  184         u_long  snd_ssthresh_prev;      /* ssthresh prior to retransmit */
  185         tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
  186         int     t_sndzerowin;           /* zero-window updates sent */
  187         u_int   t_badrxtwin;            /* window for retransmit recovery */
  188         u_char  snd_limited;            /* segments limited transmitted */
  189 /* SACK related state */
  190         int     snd_numholes;           /* number of holes seen by sender */
  191         TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
  192                                         /* SACK scoreboard (sorted) */
  193         tcp_seq snd_fack;               /* last seq number(+1) sack'd by rcv'r*/
  194         int     rcv_numsacks;           /* # distinct sack blks present */
  195         struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
  196         tcp_seq sack_newdata;           /* New data xmitted in this recovery
  197                                            episode starts at this seq number */
  198         struct sackhint sackhint;       /* SACK scoreboard hint */
  199         int     t_rttlow;               /* smallest observerved RTT */
  200         u_int32_t       rfbuf_ts;       /* recv buffer autoscaling timestamp */
  201         int     rfbuf_cnt;              /* recv buffer autoscaling byte count */
  202         struct toedev   *tod;           /* toedev handling this connection */
  203         int     t_sndrexmitpack;        /* retransmit packets sent */
  204         int     t_rcvoopack;            /* out-of-order packets received */
  205         void    *t_toe;                 /* TOE pcb pointer */
  206         int     t_bytes_acked;          /* # bytes acked during current RTT */
  207         struct cc_algo  *cc_algo;       /* congestion control algorithm */
  208         struct cc_var   *ccv;           /* congestion control specific vars */
  209         struct osd      *osd;           /* storage for Khelp module data */
  210 
  211         u_int   t_keepinit;             /* time to establish connection */
  212         u_int   t_keepidle;             /* time before keepalive probes begin */
  213         u_int   t_keepintvl;            /* interval between keepalives */
  214         u_int   t_keepcnt;              /* number of keepalives before close */
  215 
  216         u_int   t_tsomax;               /* TSO total burst length limit in bytes */
  217         u_int   t_pmtud_saved_maxopd;   /* pre-blackhole MSS */
  218         u_int   t_flags2;               /* More tcpcb flags storage */
  219 
  220         uint32_t t_ispare[6];           /* 5 UTO, 1 TBD */
  221 #if defined(_KERNEL) && defined(TCP_RFC7413)
  222         void    *t_pspare2[3];          /* 1 TCP_SIGNATURE, 2 TBD */
  223         unsigned int *t_tfo_pending;    /* TCP Fast Open pending counter */
  224 #else
  225         void    *t_pspare2[4];          /* 1 TCP_SIGNATURE, 3 TBD */
  226 #endif
  227 #if defined(_KERNEL) && defined(TCP_RFC7413)
  228         uint64_t _pad[4];               /* 4 TBD (1-2 CC/RTT?) */
  229         uint64_t t_tfo_cookie;          /* TCP Fast Open cookie */
  230 #else
  231         uint64_t _pad[5];               /* 5 TBD (1-2 CC/RTT?) */
  232 #endif
  233         uint32_t t_tsomaxsegcount;      /* TSO maximum segment count */
  234         uint32_t t_tsomaxsegsize;       /* TSO maximum segment size in bytes */
  235 };
  236 
  237 /*
  238  * Flags and utility macros for the t_flags field.
  239  */
  240 #define TF_ACKNOW       0x000001        /* ack peer immediately */
  241 #define TF_DELACK       0x000002        /* ack, but try to delay it */
  242 #define TF_NODELAY      0x000004        /* don't delay packets to coalesce */
  243 #define TF_NOOPT        0x000008        /* don't use tcp options */
  244 #define TF_SENTFIN      0x000010        /* have sent FIN */
  245 #define TF_REQ_SCALE    0x000020        /* have/will request window scaling */
  246 #define TF_RCVD_SCALE   0x000040        /* other side has requested scaling */
  247 #define TF_REQ_TSTMP    0x000080        /* have/will request timestamps */
  248 #define TF_RCVD_TSTMP   0x000100        /* a timestamp was received in SYN */
  249 #define TF_SACK_PERMIT  0x000200        /* other side said I could SACK */
  250 #define TF_NEEDSYN      0x000400        /* send SYN (implicit state) */
  251 #define TF_NEEDFIN      0x000800        /* send FIN (implicit state) */
  252 #define TF_NOPUSH       0x001000        /* don't push */
  253 #define TF_PREVVALID    0x002000        /* saved values for bad rxmit valid */
  254 #define TF_MORETOCOME   0x010000        /* More data to be appended to sock */
  255 #define TF_LQ_OVERFLOW  0x020000        /* listen queue overflow */
  256 #define TF_LASTIDLE     0x040000        /* connection was previously idle */
  257 #define TF_RXWIN0SENT   0x080000        /* sent a receiver win 0 in response */
  258 #define TF_FASTRECOVERY 0x100000        /* in NewReno Fast Recovery */
  259 #define TF_WASFRECOVERY 0x200000        /* was in NewReno Fast Recovery */
  260 #define TF_SIGNATURE    0x400000        /* require MD5 digests (RFC2385) */
  261 #define TF_FORCEDATA    0x800000        /* force out a byte */
  262 #define TF_TSO          0x1000000       /* TSO enabled on this connection */
  263 #define TF_TOE          0x2000000       /* this connection is offloaded */
  264 #define TF_ECN_PERMIT   0x4000000       /* connection ECN-ready */
  265 #define TF_ECN_SND_CWR  0x8000000       /* ECN CWR in queue */
  266 #define TF_ECN_SND_ECE  0x10000000      /* ECN ECE in queue */
  267 #define TF_CONGRECOVERY 0x20000000      /* congestion recovery mode */
  268 #define TF_WASCRECOVERY 0x40000000      /* was in congestion recovery */
  269 #define TF_FASTOPEN     0x80000000      /* TCP Fast Open indication */
  270 
  271 #define IN_FASTRECOVERY(t_flags)        (t_flags & TF_FASTRECOVERY)
  272 #define ENTER_FASTRECOVERY(t_flags)     t_flags |= TF_FASTRECOVERY
  273 #define EXIT_FASTRECOVERY(t_flags)      t_flags &= ~TF_FASTRECOVERY
  274 
  275 #define IN_CONGRECOVERY(t_flags)        (t_flags & TF_CONGRECOVERY)
  276 #define ENTER_CONGRECOVERY(t_flags)     t_flags |= TF_CONGRECOVERY
  277 #define EXIT_CONGRECOVERY(t_flags)      t_flags &= ~TF_CONGRECOVERY
  278 
  279 #define IN_RECOVERY(t_flags) (t_flags & (TF_CONGRECOVERY | TF_FASTRECOVERY))
  280 #define ENTER_RECOVERY(t_flags) t_flags |= (TF_CONGRECOVERY | TF_FASTRECOVERY)
  281 #define EXIT_RECOVERY(t_flags) t_flags &= ~(TF_CONGRECOVERY | TF_FASTRECOVERY)
  282 
  283 #define BYTES_THIS_ACK(tp, th)  (th->th_ack - tp->snd_una)
  284 
  285 /*
  286  * Flags for the t_oobflags field.
  287  */
  288 #define TCPOOB_HAVEDATA 0x01
  289 #define TCPOOB_HADDATA  0x02
  290 
  291 #ifdef TCP_SIGNATURE
  292 /*
  293  * Defines which are needed by the xform_tcp module and tcp_[in|out]put
  294  * for SADB verification and lookup.
  295  */
  296 #define TCP_SIGLEN      16      /* length of computed digest in bytes */
  297 #define TCP_KEYLEN_MIN  1       /* minimum length of TCP-MD5 key */
  298 #define TCP_KEYLEN_MAX  80      /* maximum length of TCP-MD5 key */
  299 /*
  300  * Only a single SA per host may be specified at this time. An SPI is
  301  * needed in order for the KEY_ALLOCSA() lookup to work.
  302  */
  303 #define TCP_SIG_SPI     0x1000
  304 #endif /* TCP_SIGNATURE */
  305 
  306 /*
  307  * Flags for PLPMTU handling, t_flags2
  308  */
  309 #define TF2_PLPMTU_BLACKHOLE    0x00000001 /* Possible PLPMTUD Black Hole. */
  310 #define TF2_PLPMTU_PMTUD        0x00000002 /* Allowed to attempt PLPMTUD. */
  311 #define TF2_PLPMTU_MAXSEGSNT    0x00000004 /* Last seg sent was full seg. */
  312 
  313 /*
  314  * Structure to hold TCP options that are only used during segment
  315  * processing (in tcp_input), but not held in the tcpcb.
  316  * It's basically used to reduce the number of parameters
  317  * to tcp_dooptions and tcp_addoptions.
  318  * The binary order of the to_flags is relevant for packing of the
  319  * options in tcp_addoptions.
  320  */
  321 struct tcpopt {
  322         u_int64_t       to_flags;       /* which options are present */
  323 #define TOF_MSS         0x0001          /* maximum segment size */
  324 #define TOF_SCALE       0x0002          /* window scaling */
  325 #define TOF_SACKPERM    0x0004          /* SACK permitted */
  326 #define TOF_TS          0x0010          /* timestamp */
  327 #define TOF_SIGNATURE   0x0040          /* TCP-MD5 signature option (RFC2385) */
  328 #define TOF_SACK        0x0080          /* Peer sent SACK option */
  329 #define TOF_FASTOPEN    0x0100          /* TCP Fast Open (TFO) cookie */
  330 #define TOF_MAXOPT      0x0200
  331         u_int32_t       to_tsval;       /* new timestamp */
  332         u_int32_t       to_tsecr;       /* reflected timestamp */
  333         u_char          *to_sacks;      /* pointer to the first SACK blocks */
  334         u_char          *to_signature;  /* pointer to the TCP-MD5 signature */
  335         u_char          *to_tfo_cookie; /* pointer to the TFO cookie */
  336         u_int16_t       to_mss;         /* maximum segment size */
  337         u_int8_t        to_wscale;      /* window scaling */
  338         u_int8_t        to_nsacks;      /* number of SACK blocks */
  339         u_int8_t        to_tfo_len;     /* TFO cookie length */
  340         u_int32_t       to_spare;       /* UTO */
  341 };
  342 
  343 /*
  344  * Flags for tcp_dooptions.
  345  */
  346 #define TO_SYN          0x01            /* parse SYN-only options */
  347 
  348 struct hc_metrics_lite {        /* must stay in sync with hc_metrics */
  349         u_long  rmx_mtu;        /* MTU for this path */
  350         u_long  rmx_ssthresh;   /* outbound gateway buffer limit */
  351         u_long  rmx_rtt;        /* estimated round trip time */
  352         u_long  rmx_rttvar;     /* estimated rtt variance */
  353         u_long  rmx_bandwidth;  /* estimated bandwidth */
  354         u_long  rmx_cwnd;       /* congestion window */
  355         u_long  rmx_sendpipe;   /* outbound delay-bandwidth product */
  356         u_long  rmx_recvpipe;   /* inbound delay-bandwidth product */
  357 };
  358 
  359 /*
  360  * Used by tcp_maxmtu() to communicate interface specific features
  361  * and limits at the time of connection setup.
  362  */
  363 struct tcp_ifcap {
  364         int     ifcap;
  365         u_int   tsomax;
  366         u_int   tsomaxsegcount;
  367         u_int   tsomaxsegsize;
  368 };
  369 
  370 #ifndef _NETINET_IN_PCB_H_
  371 struct in_conninfo;
  372 #endif /* _NETINET_IN_PCB_H_ */
  373 
  374 struct tcptw {
  375         struct inpcb    *tw_inpcb;      /* XXX back pointer to internet pcb */
  376         tcp_seq         snd_nxt;
  377         tcp_seq         rcv_nxt;
  378         tcp_seq         iss;
  379         tcp_seq         irs;
  380         u_short         last_win;       /* cached window value */
  381         u_short         tw_so_options;  /* copy of so_options */
  382         struct ucred    *tw_cred;       /* user credentials */
  383         u_int32_t       t_recent;
  384         u_int32_t       ts_offset;      /* our timestamp offset */
  385         u_int           t_starttime;
  386         int             tw_time;
  387         TAILQ_ENTRY(tcptw) tw_2msl;
  388         void            *tw_pspare;     /* TCP_SIGNATURE */
  389         u_int           *tw_spare;      /* TCP_SIGNATURE */
  390 };
  391 
  392 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
  393 #define intotw(ip)      ((struct tcptw *)(ip)->inp_ppcb)
  394 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
  395 
  396 /*
  397  * The smoothed round-trip time and estimated variance
  398  * are stored as fixed point numbers scaled by the values below.
  399  * For convenience, these scales are also used in smoothing the average
  400  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
  401  * With these scales, srtt has 3 bits to the right of the binary point,
  402  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
  403  * binary point, and is smoothed with an ALPHA of 0.75.
  404  */
  405 #define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
  406 #define TCP_RTT_SHIFT           5       /* shift for srtt; 3 bits frac. */
  407 #define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 2 bits */
  408 #define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 2 bits */
  409 #define TCP_DELTA_SHIFT         2       /* see tcp_input.c */
  410 
  411 /*
  412  * The initial retransmission should happen at rtt + 4 * rttvar.
  413  * Because of the way we do the smoothing, srtt and rttvar
  414  * will each average +1/2 tick of bias.  When we compute
  415  * the retransmit timer, we want 1/2 tick of rounding and
  416  * 1 extra tick because of +-1/2 tick uncertainty in the
  417  * firing of the timer.  The bias will give us exactly the
  418  * 1.5 tick we need.  But, because the bias is
  419  * statistical, we have to test that we don't drop below
  420  * the minimum feasible timer (which is 2 ticks).
  421  * This version of the macro adapted from a paper by Lawrence
  422  * Brakmo and Larry Peterson which outlines a problem caused
  423  * by insufficient precision in the original implementation,
  424  * which results in inappropriately large RTO values for very
  425  * fast networks.
  426  */
  427 #define TCP_REXMTVAL(tp) \
  428         max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
  429           + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
  430 
  431 /*
  432  * TCP statistics.
  433  * Many of these should be kept per connection,
  434  * but that's inconvenient at the moment.
  435  */
  436 struct  tcpstat {
  437         uint64_t tcps_connattempt;      /* connections initiated */
  438         uint64_t tcps_accepts;          /* connections accepted */
  439         uint64_t tcps_connects;         /* connections established */
  440         uint64_t tcps_drops;            /* connections dropped */
  441         uint64_t tcps_conndrops;        /* embryonic connections dropped */
  442         uint64_t tcps_minmssdrops;      /* average minmss too low drops */
  443         uint64_t tcps_closed;           /* conn. closed (includes drops) */
  444         uint64_t tcps_segstimed;        /* segs where we tried to get rtt */
  445         uint64_t tcps_rttupdated;       /* times we succeeded */
  446         uint64_t tcps_delack;           /* delayed acks sent */
  447         uint64_t tcps_timeoutdrop;      /* conn. dropped in rxmt timeout */
  448         uint64_t tcps_rexmttimeo;       /* retransmit timeouts */
  449         uint64_t tcps_persisttimeo;     /* persist timeouts */
  450         uint64_t tcps_keeptimeo;        /* keepalive timeouts */
  451         uint64_t tcps_keepprobe;        /* keepalive probes sent */
  452         uint64_t tcps_keepdrops;        /* connections dropped in keepalive */
  453 
  454         uint64_t tcps_sndtotal;         /* total packets sent */
  455         uint64_t tcps_sndpack;          /* data packets sent */
  456         uint64_t tcps_sndbyte;          /* data bytes sent */
  457         uint64_t tcps_sndrexmitpack;    /* data packets retransmitted */
  458         uint64_t tcps_sndrexmitbyte;    /* data bytes retransmitted */
  459         uint64_t tcps_sndrexmitbad;     /* unnecessary packet retransmissions */
  460         uint64_t tcps_sndacks;          /* ack-only packets sent */
  461         uint64_t tcps_sndprobe;         /* window probes sent */
  462         uint64_t tcps_sndurg;           /* packets sent with URG only */
  463         uint64_t tcps_sndwinup;         /* window update-only packets sent */
  464         uint64_t tcps_sndctrl;          /* control (SYN|FIN|RST) packets sent */
  465 
  466         uint64_t tcps_rcvtotal;         /* total packets received */
  467         uint64_t tcps_rcvpack;          /* packets received in sequence */
  468         uint64_t tcps_rcvbyte;          /* bytes received in sequence */
  469         uint64_t tcps_rcvbadsum;        /* packets received with ccksum errs */
  470         uint64_t tcps_rcvbadoff;        /* packets received with bad offset */
  471         uint64_t tcps_rcvmemdrop;       /* packets dropped for lack of memory */
  472         uint64_t tcps_rcvshort;         /* packets received too short */
  473         uint64_t tcps_rcvduppack;       /* duplicate-only packets received */
  474         uint64_t tcps_rcvdupbyte;       /* duplicate-only bytes received */
  475         uint64_t tcps_rcvpartduppack;   /* packets with some duplicate data */
  476         uint64_t tcps_rcvpartdupbyte;   /* dup. bytes in part-dup. packets */
  477         uint64_t tcps_rcvoopack;        /* out-of-order packets received */
  478         uint64_t tcps_rcvoobyte;        /* out-of-order bytes received */
  479         uint64_t tcps_rcvpackafterwin;  /* packets with data after window */
  480         uint64_t tcps_rcvbyteafterwin;  /* bytes rcvd after window */
  481         uint64_t tcps_rcvafterclose;    /* packets rcvd after "close" */
  482         uint64_t tcps_rcvwinprobe;      /* rcvd window probe packets */
  483         uint64_t tcps_rcvdupack;        /* rcvd duplicate acks */
  484         uint64_t tcps_rcvacktoomuch;    /* rcvd acks for unsent data */
  485         uint64_t tcps_rcvackpack;       /* rcvd ack packets */
  486         uint64_t tcps_rcvackbyte;       /* bytes acked by rcvd acks */
  487         uint64_t tcps_rcvwinupd;        /* rcvd window update packets */
  488         uint64_t tcps_pawsdrop;         /* segments dropped due to PAWS */
  489         uint64_t tcps_predack;          /* times hdr predict ok for acks */
  490         uint64_t tcps_preddat;          /* times hdr predict ok for data pkts */
  491         uint64_t tcps_pcbcachemiss;
  492         uint64_t tcps_cachedrtt;        /* times cached RTT in route updated */
  493         uint64_t tcps_cachedrttvar;     /* times cached rttvar updated */
  494         uint64_t tcps_cachedssthresh;   /* times cached ssthresh updated */
  495         uint64_t tcps_usedrtt;          /* times RTT initialized from route */
  496         uint64_t tcps_usedrttvar;       /* times RTTVAR initialized from rt */
  497         uint64_t tcps_usedssthresh;     /* times ssthresh initialized from rt*/
  498         uint64_t tcps_persistdrop;      /* timeout in persist state */
  499         uint64_t tcps_badsyn;           /* bogus SYN, e.g. premature ACK */
  500         uint64_t tcps_mturesent;        /* resends due to MTU discovery */
  501         uint64_t tcps_listendrop;       /* listen queue overflows */
  502         uint64_t tcps_badrst;           /* ignored RSTs in the window */
  503 
  504         uint64_t tcps_sc_added;         /* entry added to syncache */
  505         uint64_t tcps_sc_retransmitted; /* syncache entry was retransmitted */
  506         uint64_t tcps_sc_dupsyn;        /* duplicate SYN packet */
  507         uint64_t tcps_sc_dropped;       /* could not reply to packet */
  508         uint64_t tcps_sc_completed;     /* successful extraction of entry */
  509         uint64_t tcps_sc_bucketoverflow;/* syncache per-bucket limit hit */
  510         uint64_t tcps_sc_cacheoverflow; /* syncache cache limit hit */
  511         uint64_t tcps_sc_reset;         /* RST removed entry from syncache */
  512         uint64_t tcps_sc_stale;         /* timed out or listen socket gone */
  513         uint64_t tcps_sc_aborted;       /* syncache entry aborted */
  514         uint64_t tcps_sc_badack;        /* removed due to bad ACK */
  515         uint64_t tcps_sc_unreach;       /* ICMP unreachable received */
  516         uint64_t tcps_sc_zonefail;      /* zalloc() failed */
  517         uint64_t tcps_sc_sendcookie;    /* SYN cookie sent */
  518         uint64_t tcps_sc_recvcookie;    /* SYN cookie received */
  519 
  520         uint64_t tcps_hc_added;         /* entry added to hostcache */
  521         uint64_t tcps_hc_bucketoverflow;/* hostcache per bucket limit hit */
  522 
  523         uint64_t tcps_finwait2_drops;    /* Drop FIN_WAIT_2 connection after time limit */
  524 
  525         /* SACK related stats */
  526         uint64_t tcps_sack_recovery_episode; /* SACK recovery episodes */
  527         uint64_t tcps_sack_rexmits;         /* SACK rexmit segments   */
  528         uint64_t tcps_sack_rexmit_bytes;    /* SACK rexmit bytes      */
  529         uint64_t tcps_sack_rcv_blocks;      /* SACK blocks (options) received */
  530         uint64_t tcps_sack_send_blocks;     /* SACK blocks (options) sent     */
  531         uint64_t tcps_sack_sboverflow;      /* times scoreboard overflowed */
  532         
  533         /* ECN related stats */
  534         uint64_t tcps_ecn_ce;           /* ECN Congestion Experienced */
  535         uint64_t tcps_ecn_ect0;         /* ECN Capable Transport */
  536         uint64_t tcps_ecn_ect1;         /* ECN Capable Transport */
  537         uint64_t tcps_ecn_shs;          /* ECN successful handshakes */
  538         uint64_t tcps_ecn_rcwnd;        /* # times ECN reduced the cwnd */
  539 
  540         /* TCP_SIGNATURE related stats */
  541         uint64_t tcps_sig_rcvgoodsig;   /* Total matching signature received */
  542         uint64_t tcps_sig_rcvbadsig;    /* Total bad signature received */
  543         uint64_t tcps_sig_err_buildsig; /* Mismatching signature received */
  544         uint64_t tcps_sig_err_sigopt;   /* No signature expected by socket */
  545         uint64_t tcps_sig_err_nosigopt; /* No signature provided by segment */
  546 
  547         uint64_t _pad[12];              /* 6 UTO, 6 TBD */
  548 };
  549 
  550 #ifdef _KERNEL
  551 #include <sys/counter.h>
  552 
  553 VNET_PCPUSTAT_DECLARE(struct tcpstat, tcpstat); /* tcp statistics */
  554 /*
  555  * In-kernel consumers can use these accessor macros directly to update
  556  * stats.
  557  */
  558 #define TCPSTAT_ADD(name, val)  \
  559     VNET_PCPUSTAT_ADD(struct tcpstat, tcpstat, name, (val))
  560 #define TCPSTAT_INC(name)       TCPSTAT_ADD(name, 1)
  561 
  562 /*
  563  * Kernel module consumers must use this accessor macro.
  564  */
  565 void    kmod_tcpstat_inc(int statnum);
  566 #define KMOD_TCPSTAT_INC(name)                                          \
  567     kmod_tcpstat_inc(offsetof(struct tcpstat, name) / sizeof(uint64_t))
  568 
  569 /*
  570  * TCP specific helper hook point identifiers.
  571  */
  572 #define HHOOK_TCP_EST_IN                0
  573 #define HHOOK_TCP_EST_OUT               1
  574 #define HHOOK_TCP_LAST                  HHOOK_TCP_EST_OUT
  575 
  576 struct tcp_hhook_data {
  577         struct tcpcb    *tp;
  578         struct tcphdr   *th;
  579         struct tcpopt   *to;
  580         long            len;
  581         int             tso;
  582         tcp_seq         curack;
  583 };
  584 #endif
  585 
  586 /*
  587  * TCB structure exported to user-land via sysctl(3).
  588  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
  589  * included.  Not all of our clients do.
  590  */
  591 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
  592 struct xtcp_timer {
  593         int tt_rexmt;   /* retransmit timer */
  594         int tt_persist; /* retransmit persistence */
  595         int tt_keep;    /* keepalive */
  596         int tt_2msl;    /* 2*msl TIME_WAIT timer */
  597         int tt_delack;  /* delayed ACK timer */
  598         int t_rcvtime;  /* Time since last packet received */
  599 };
  600 struct  xtcpcb {
  601         size_t  xt_len;
  602         struct  inpcb   xt_inp;
  603         struct  tcpcb   xt_tp;
  604         struct  xsocket xt_socket;
  605         struct  xtcp_timer xt_timer;
  606         u_quad_t        xt_alignment_hack;
  607 };
  608 #endif
  609 
  610 /*
  611  * Names for TCP sysctl objects
  612  */
  613 #define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
  614 #define TCPCTL_MSSDFLT          3       /* MSS default */
  615 #define TCPCTL_STATS            4       /* statistics (read-only) */
  616 #define TCPCTL_RTTDFLT          5       /* default RTT estimate */
  617 #define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
  618 #define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
  619 #define TCPCTL_SENDSPACE        8       /* send buffer space */
  620 #define TCPCTL_RECVSPACE        9       /* receive buffer space */
  621 #define TCPCTL_KEEPINIT         10      /* timeout for establishing syn */
  622 #define TCPCTL_PCBLIST          11      /* list of all outstanding PCBs */
  623 #define TCPCTL_DELACKTIME       12      /* time before sending delayed ACK */
  624 #define TCPCTL_V6MSSDFLT        13      /* MSS default for IPv6 */
  625 #define TCPCTL_SACK             14      /* Selective Acknowledgement,rfc 2018 */
  626 #define TCPCTL_DROP             15      /* drop tcp connection */
  627 #define TCPCTL_MAXID            16
  628 #define TCPCTL_FINWAIT2_TIMEOUT        17
  629 
  630 #ifdef _KERNEL
  631 #ifdef SYSCTL_DECL
  632 SYSCTL_DECL(_net_inet_tcp);
  633 SYSCTL_DECL(_net_inet_tcp_sack);
  634 MALLOC_DECLARE(M_TCPLOG);
  635 #endif
  636 
  637 VNET_DECLARE(struct inpcbhead, tcb);            /* queue of active tcpcb's */
  638 VNET_DECLARE(struct inpcbinfo, tcbinfo);
  639 extern  int tcp_log_in_vain;
  640 VNET_DECLARE(int, tcp_mssdflt); /* XXX */
  641 VNET_DECLARE(int, tcp_minmss);
  642 VNET_DECLARE(int, tcp_delack_enabled);
  643 VNET_DECLARE(int, tcp_do_rfc3390);
  644 VNET_DECLARE(int, tcp_do_initcwnd10);
  645 VNET_DECLARE(int, tcp_sendspace);
  646 VNET_DECLARE(int, tcp_recvspace);
  647 VNET_DECLARE(int, path_mtu_discovery);
  648 VNET_DECLARE(int, tcp_do_rfc3465);
  649 VNET_DECLARE(int, tcp_abc_l_var);
  650 #define V_tcb                   VNET(tcb)
  651 #define V_tcbinfo               VNET(tcbinfo)
  652 #define V_tcp_mssdflt           VNET(tcp_mssdflt)
  653 #define V_tcp_minmss            VNET(tcp_minmss)
  654 #define V_tcp_delack_enabled    VNET(tcp_delack_enabled)
  655 #define V_tcp_do_rfc3390        VNET(tcp_do_rfc3390)
  656 #define V_tcp_do_initcwnd10     VNET(tcp_do_initcwnd10)
  657 #define V_tcp_sendspace         VNET(tcp_sendspace)
  658 #define V_tcp_recvspace         VNET(tcp_recvspace)
  659 #define V_path_mtu_discovery    VNET(path_mtu_discovery)
  660 #define V_tcp_do_rfc3465        VNET(tcp_do_rfc3465)
  661 #define V_tcp_abc_l_var         VNET(tcp_abc_l_var)
  662 
  663 VNET_DECLARE(int, tcp_do_sack);                 /* SACK enabled/disabled */
  664 VNET_DECLARE(int, tcp_sc_rst_sock_fail);        /* RST on sock alloc failure */
  665 #define V_tcp_do_sack           VNET(tcp_do_sack)
  666 #define V_tcp_sc_rst_sock_fail  VNET(tcp_sc_rst_sock_fail)
  667 
  668 VNET_DECLARE(int, tcp_do_ecn);                  /* TCP ECN enabled/disabled */
  669 VNET_DECLARE(int, tcp_ecn_maxretries);
  670 #define V_tcp_do_ecn            VNET(tcp_do_ecn)
  671 #define V_tcp_ecn_maxretries    VNET(tcp_ecn_maxretries)
  672 
  673 VNET_DECLARE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST + 1]);
  674 #define V_tcp_hhh               VNET(tcp_hhh)
  675 
  676 VNET_DECLARE(int, tcp_do_rfc6675_pipe);
  677 #define V_tcp_do_rfc6675_pipe   VNET(tcp_do_rfc6675_pipe)
  678 
  679 int      tcp_addoptions(struct tcpopt *, u_char *);
  680 int      tcp_ccalgounload(struct cc_algo *unload_algo);
  681 struct tcpcb *
  682          tcp_close(struct tcpcb *);
  683 void     tcp_discardcb(struct tcpcb *);
  684 void     tcp_twstart(struct tcpcb *);
  685 #if 0
  686 int      tcp_twrecycleable(struct tcptw *tw);
  687 #endif
  688 void     tcp_twclose(struct tcptw *, int);
  689 void     tcp_ctlinput(int, struct sockaddr *, void *);
  690 int      tcp_ctloutput(struct socket *, struct sockopt *);
  691 struct tcpcb *
  692          tcp_drop(struct tcpcb *, int);
  693 void     tcp_drain(void);
  694 void     tcp_init(void);
  695 #ifdef VIMAGE
  696 void     tcp_destroy(void);
  697 #endif
  698 void     tcp_fini(void *);
  699 char    *tcp_log_addrs(struct in_conninfo *, struct tcphdr *, void *,
  700             const void *);
  701 char    *tcp_log_vain(struct in_conninfo *, struct tcphdr *, void *,
  702             const void *);
  703 int      tcp_reass(struct tcpcb *, struct tcphdr *, int *, struct mbuf *);
  704 void     tcp_reass_global_init(void);
  705 void     tcp_reass_flush(struct tcpcb *);
  706 void     tcp_input(struct mbuf *, int);
  707 int      tcp_autorcvbuf(struct mbuf *, struct tcphdr *, struct socket *,
  708             struct tcpcb *, int);
  709 u_long   tcp_maxmtu(struct in_conninfo *, struct tcp_ifcap *);
  710 u_long   tcp_maxmtu6(struct in_conninfo *, struct tcp_ifcap *);
  711 void     tcp_mss_update(struct tcpcb *, int, int, struct hc_metrics_lite *,
  712             struct tcp_ifcap *);
  713 void     tcp_mss(struct tcpcb *, int);
  714 int      tcp_mssopt(struct in_conninfo *);
  715 struct inpcb *
  716          tcp_drop_syn_sent(struct inpcb *, int);
  717 struct inpcb *
  718          tcp_mtudisc(struct inpcb *, int);
  719 struct tcpcb *
  720          tcp_newtcpcb(struct inpcb *);
  721 int      tcp_output(struct tcpcb *);
  722 void     tcp_state_change(struct tcpcb *, int);
  723 void     tcp_respond(struct tcpcb *, void *,
  724             struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
  725 void     tcp_tw_init(void);
  726 #ifdef VIMAGE
  727 void     tcp_tw_destroy(void);
  728 #endif
  729 void     tcp_tw_zone_change(void);
  730 int      tcp_twcheck(struct inpcb *, struct tcpopt *, struct tcphdr *,
  731             struct mbuf *, int);
  732 void     tcp_setpersist(struct tcpcb *);
  733 #ifdef TCP_SIGNATURE
  734 int      tcp_signature_compute(struct mbuf *, int, int, int, u_char *, u_int);
  735 int      tcp_signature_verify(struct mbuf *, int, int, int, struct tcpopt *,
  736             struct tcphdr *, u_int);
  737 #endif
  738 void     tcp_slowtimo(void);
  739 struct tcptemp *
  740          tcpip_maketemplate(struct inpcb *);
  741 void     tcpip_fillheaders(struct inpcb *, void *, void *);
  742 void     tcp_timer_activate(struct tcpcb *, uint32_t, u_int);
  743 int      tcp_timer_active(struct tcpcb *, uint32_t);
  744 void     tcp_timer_stop(struct tcpcb *, uint32_t);
  745 void     tcp_trace(short, short, struct tcpcb *, void *, struct tcphdr *, int);
  746 /*
  747  * All tcp_hc_* functions are IPv4 and IPv6 (via in_conninfo)
  748  */
  749 void     tcp_hc_init(void);
  750 #ifdef VIMAGE
  751 void     tcp_hc_destroy(void);
  752 #endif
  753 void     tcp_hc_get(struct in_conninfo *, struct hc_metrics_lite *);
  754 u_long   tcp_hc_getmtu(struct in_conninfo *);
  755 void     tcp_hc_updatemtu(struct in_conninfo *, u_long);
  756 void     tcp_hc_update(struct in_conninfo *, struct hc_metrics_lite *);
  757 
  758 extern  struct pr_usrreqs tcp_usrreqs;
  759 tcp_seq tcp_new_isn(struct tcpcb *);
  760 
  761 int      tcp_sack_doack(struct tcpcb *, struct tcpopt *, tcp_seq);
  762 void     tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_laststart, tcp_seq rcv_lastend);
  763 void     tcp_clean_sackreport(struct tcpcb *tp);
  764 void     tcp_sack_adjust(struct tcpcb *tp);
  765 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
  766 void     tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
  767 void     tcp_free_sackholes(struct tcpcb *tp);
  768 int      tcp_newreno(struct tcpcb *, struct tcphdr *);
  769 int      tcp_compute_pipe(struct tcpcb *);
  770 
  771 void    cc_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type);
  772 
  773 static inline void
  774 tcp_fields_to_host(struct tcphdr *th)
  775 {
  776 
  777         th->th_seq = ntohl(th->th_seq);
  778         th->th_ack = ntohl(th->th_ack);
  779         th->th_win = ntohs(th->th_win);
  780         th->th_urp = ntohs(th->th_urp);
  781 }
  782 
  783 #ifdef TCP_SIGNATURE
  784 static inline void
  785 tcp_fields_to_net(struct tcphdr *th)
  786 {
  787 
  788         th->th_seq = htonl(th->th_seq);
  789         th->th_ack = htonl(th->th_ack);
  790         th->th_win = htons(th->th_win);
  791         th->th_urp = htons(th->th_urp);
  792 }
  793 #endif
  794 #endif /* _KERNEL */
  795 
  796 #endif /* _NETINET_TCP_VAR_H_ */

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