include/uapi/linux/tcp.h

   1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              Definitions for the TCP protocol.
   8  *
   9  * Version:     @(#)tcp.h       1.0.2   04/28/93
  10  *
  11  * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *
  13  *              This program is free software; you can redistribute it and/or
  14  *              modify it under the terms of the GNU General Public License
  15  *              as published by the Free Software Foundation; either version
  16  *              2 of the License, or (at your option) any later version.
  17  */
  18 #ifndef _UAPI_LINUX_TCP_H
  19 #define _UAPI_LINUX_TCP_H
  20
  21 #include <linux/types.h>
  22 #include <asm/byteorder.h>
  23 #include <linux/socket.h>
  24
  25 struct tcphdr {
  26         __be16  source;
  27         __be16  dest;
  28         __be32  seq;
  29         __be32  ack_seq;
  30 #if defined(__LITTLE_ENDIAN_BITFIELD)
  31         __u16   res1:4,
  32                 doff:4,
  33                 fin:1,
  34                 syn:1,
  35                 rst:1,
  36                 psh:1,
  37                 ack:1,
  38                 urg:1,
  39                 ece:1,
  40                 cwr:1;
  41 #elif defined(__BIG_ENDIAN_BITFIELD)
  42         __u16   doff:4,
  43                 res1:4,
  44                 cwr:1,
  45                 ece:1,
  46                 urg:1,
  47                 ack:1,
  48                 psh:1,
  49                 rst:1,
  50                 syn:1,
  51                 fin:1;
  52 #else
  53 #error  "Adjust your <asm/byteorder.h> defines"
  54 #endif
  55         __be16  window;
  56         __sum16 check;
  57         __be16  urg_ptr;
  58 };
  59
  60 /*
  61  *      The union cast uses a gcc extension to avoid aliasing problems
  62  *  (union is compatible to any of its members)
  63  *  This means this part of the code is -fstrict-aliasing safe now.
  64  */
  65 union tcp_word_hdr {
  66         struct tcphdr hdr;
  67         __be32        words[5];
  68 };
  69
  70 #define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])
  71
  72 enum {
  73         TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000),
  74         TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000),
  75         TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000),
  76         TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000),
  77         TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000),
  78         TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000),
  79         TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000),
  80         TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000),
  81         TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000),
  82         TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000)
  83 };
  84
  85 /*
  86  * TCP general constants
  87  */
  88 #define TCP_MSS_DEFAULT          536U   /* IPv4 (RFC1122, RFC2581) */
  89 #define TCP_MSS_DESIRED         1220U   /* IPv6 (tunneled), EDNS0 (RFC3226) */
  90
  91 /* TCP socket options */
  92 #define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */
  93 #define TCP_MAXSEG              2       /* Limit MSS */
  94 #define TCP_CORK                3       /* Never send partially complete segments */
  95 #define TCP_KEEPIDLE            4       /* Start keeplives after this period */
  96 #define TCP_KEEPINTVL           5       /* Interval between keepalives */
  97 #define TCP_KEEPCNT             6       /* Number of keepalives before death */
  98 #define TCP_SYNCNT              7       /* Number of SYN retransmits */
  99 #define TCP_LINGER2             8       /* Life time of orphaned FIN-WAIT-2 state */
 100 #define TCP_DEFER_ACCEPT        9       /* Wake up listener only when data arrive */
 101 #define TCP_WINDOW_CLAMP        10      /* Bound advertised window */
 102 #define TCP_INFO                11      /* Information about this connection. */
 103 #define TCP_QUICKACK            12      /* Block/reenable quick acks */
 104 #define TCP_CONGESTION          13      /* Congestion control algorithm */
 105 #define TCP_MD5SIG              14      /* TCP MD5 Signature (RFC2385) */
 106 #define TCP_THIN_LINEAR_TIMEOUTS 16     /* Use linear timeouts for thin streams*/
 107 #define TCP_THIN_DUPACK         17      /* Fast retrans. after 1 dupack */
 108 #define TCP_USER_TIMEOUT        18      /* How long for loss retry before timeout */
 109 #define TCP_REPAIR              19      /* TCP sock is under repair right now */
 110 #define TCP_REPAIR_QUEUE        20
 111 #define TCP_QUEUE_SEQ           21
 112 #define TCP_REPAIR_OPTIONS      22
 113 #define TCP_FASTOPEN            23      /* Enable FastOpen on listeners */
 114 #define TCP_TIMESTAMP           24
 115 #define TCP_NOTSENT_LOWAT       25      /* limit number of unsent bytes in write queue */
 116 #define TCP_CC_INFO             26      /* Get Congestion Control (optional) info */
 117 #define TCP_SAVE_SYN            27      /* Record SYN headers for new connections */
 118 #define TCP_SAVED_SYN           28      /* Get SYN headers recorded for connection */
 119 #define TCP_REPAIR_WINDOW       29      /* Get/set window parameters */
 120 #define TCP_FASTOPEN_CONNECT    30      /* Attempt FastOpen with connect */
 121 #define TCP_ULP                 31      /* Attach a ULP to a TCP connection */
 122 #define TCP_MD5SIG_EXT          32      /* TCP MD5 Signature with extensions */
 123 #define TCP_FASTOPEN_KEY        33      /* Set the key for Fast Open (cookie) */
 124 #define TCP_FASTOPEN_NO_COOKIE  34      /* Enable TFO without a TFO cookie */
 125 #define TCP_ZEROCOPY_RECEIVE    35
 126 #define TCP_INQ                 36      /* Notify bytes available to read as a cmsg on read */
 127
 128 #define TCP_CM_INQ              TCP_INQ
 129
 130 #define TCP_TX_DELAY            37      /* delay outgoing packets by XX usec */
 131
 132 #define TCP_AO_ADD_KEY          38      /* Add/Set MKT */
 133 #define TCP_AO_DEL_KEY          39      /* Delete MKT */
 134 #define TCP_AO_INFO             40      /* Set/list TCP-AO per-socket options */
 135 #define TCP_AO_GET_KEYS         41      /* List MKT(s) */
 136 #define TCP_AO_REPAIR           42      /* Get/Set SNEs and ISNs */
 137
 138 #define TCP_IS_MPTCP            43      /* Is MPTCP being used? */
 139
 140 #define TCP_REPAIR_ON           1
 141 #define TCP_REPAIR_OFF          0
 142 #define TCP_REPAIR_OFF_NO_WP    -1      /* Turn off without window probes */
 143
 144 struct tcp_repair_opt {
 145         __u32   opt_code;
 146         __u32   opt_val;
 147 };
 148
 149 struct tcp_repair_window {
 150         __u32   snd_wl1;
 151         __u32   snd_wnd;
 152         __u32   max_window;
 153
 154         __u32   rcv_wnd;
 155         __u32   rcv_wup;
 156 };
 157
 158 enum {
 159         TCP_NO_QUEUE,
 160         TCP_RECV_QUEUE,
 161         TCP_SEND_QUEUE,
 162         TCP_QUEUES_NR,
 163 };
 164
 165 /* why fastopen failed from client perspective */
 166 enum tcp_fastopen_client_fail {
 167         TFO_STATUS_UNSPEC, /* catch-all */
 168         TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
 169         TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
 170         TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
 171 };
 172
 173 /* for TCP_INFO socket option */
 174 #define TCPI_OPT_TIMESTAMPS     1
 175 #define TCPI_OPT_SACK           2
 176 #define TCPI_OPT_WSCALE         4
 177 #define TCPI_OPT_ECN            8 /* ECN was negociated at TCP session init */
 178 #define TCPI_OPT_ECN_SEEN       16 /* we received at least one packet with ECT */
 179 #define TCPI_OPT_SYN_DATA       32 /* SYN-ACK acked data in SYN sent or rcvd */
 180 #define TCPI_OPT_USEC_TS        64 /* usec timestamps */
 181
 182 /*
 183  * Sender's congestion state indicating normal or abnormal situations
 184  * in the last round of packets sent. The state is driven by the ACK
 185  * information and timer events.
 186  */
 187 enum tcp_ca_state {
 188         /*
 189          * Nothing bad has been observed recently.
 190          * No apparent reordering, packet loss, or ECN marks.
 191          */
 192         TCP_CA_Open = 0,
 193 #define TCPF_CA_Open    (1<<TCP_CA_Open)
 194         /*
 195          * The sender enters disordered state when it has received DUPACKs or
 196          * SACKs in the last round of packets sent. This could be due to packet
 197          * loss or reordering but needs further information to confirm packets
 198          * have been lost.
 199          */
 200         TCP_CA_Disorder = 1,
 201 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 202         /*
 203          * The sender enters Congestion Window Reduction (CWR) state when it
 204          * has received ACKs with ECN-ECE marks, or has experienced congestion
 205          * or packet discard on the sender host (e.g. qdisc).
 206          */
 207         TCP_CA_CWR = 2,
 208 #define TCPF_CA_CWR     (1<<TCP_CA_CWR)
 209         /*
 210          * The sender is in fast recovery and retransmitting lost packets,
 211          * typically triggered by ACK events.
 212          */
 213         TCP_CA_Recovery = 3,
 214 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 215         /*
 216          * The sender is in loss recovery triggered by retransmission timeout.
 217          */
 218         TCP_CA_Loss = 4
 219 #define TCPF_CA_Loss    (1<<TCP_CA_Loss)
 220 };
 221
 222 struct tcp_info {
 223         __u8    tcpi_state;
 224         __u8    tcpi_ca_state;
 225         __u8    tcpi_retransmits;
 226         __u8    tcpi_probes;
 227         __u8    tcpi_backoff;
 228         __u8    tcpi_options;
 229         __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 230         __u8    tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
 231
 232         __u32   tcpi_rto;
 233         __u32   tcpi_ato;
 234         __u32   tcpi_snd_mss;
 235         __u32   tcpi_rcv_mss;
 236
 237         __u32   tcpi_unacked;
 238         __u32   tcpi_sacked;
 239         __u32   tcpi_lost;
 240         __u32   tcpi_retrans;
 241         __u32   tcpi_fackets;
 242
 243         /* Times. */
 244         __u32   tcpi_last_data_sent;
 245         __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */
 246         __u32   tcpi_last_data_recv;
 247         __u32   tcpi_last_ack_recv;
 248
 249         /* Metrics. */
 250         __u32   tcpi_pmtu;
 251         __u32   tcpi_rcv_ssthresh;
 252         __u32   tcpi_rtt;
 253         __u32   tcpi_rttvar;
 254         __u32   tcpi_snd_ssthresh;
 255         __u32   tcpi_snd_cwnd;
 256         __u32   tcpi_advmss;
 257         __u32   tcpi_reordering;
 258
 259         __u32   tcpi_rcv_rtt;
 260         __u32   tcpi_rcv_space;
 261
 262         __u32   tcpi_total_retrans;
 263
 264         __u64   tcpi_pacing_rate;
 265         __u64   tcpi_max_pacing_rate;
 266         __u64   tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
 267         __u64   tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
 268         __u32   tcpi_segs_out;       /* RFC4898 tcpEStatsPerfSegsOut */
 269         __u32   tcpi_segs_in;        /* RFC4898 tcpEStatsPerfSegsIn */
 270
 271         __u32   tcpi_notsent_bytes;
 272         __u32   tcpi_min_rtt;
 273         __u32   tcpi_data_segs_in;      /* RFC4898 tcpEStatsDataSegsIn */
 274         __u32   tcpi_data_segs_out;     /* RFC4898 tcpEStatsDataSegsOut */
 275
 276         __u64   tcpi_delivery_rate;
 277
 278         __u64   tcpi_busy_time;      /* Time (usec) busy sending data */
 279         __u64   tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
 280         __u64   tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
 281
 282         __u32   tcpi_delivered;
 283         __u32   tcpi_delivered_ce;
 284
 285         __u64   tcpi_bytes_sent;     /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
 286         __u64   tcpi_bytes_retrans;  /* RFC4898 tcpEStatsPerfOctetsRetrans */
 287         __u32   tcpi_dsack_dups;     /* RFC4898 tcpEStatsStackDSACKDups */
 288         __u32   tcpi_reord_seen;     /* reordering events seen */
 289
 290         __u32   tcpi_rcv_ooopack;    /* Out-of-order packets received */
 291
 292         __u32   tcpi_snd_wnd;        /* peer's advertised receive window after
 293                                       * scaling (bytes)
 294                                       */
 295         __u32   tcpi_rcv_wnd;        /* local advertised receive window after
 296                                       * scaling (bytes)
 297                                       */
 298
 299         __u32   tcpi_rehash;         /* PLB or timeout triggered rehash attempts */
 300
 301         __u16   tcpi_total_rto; /* Total number of RTO timeouts, including
 302                                  * SYN/SYN-ACK and recurring timeouts.
 303                                  */
 304         __u16   tcpi_total_rto_recoveries;      /* Total number of RTO
 305                                                  * recoveries, including any
 306                                                  * unfinished recovery.
 307                                                  */
 308         __u32   tcpi_total_rto_time;    /* Total time spent in RTO recoveries
 309                                          * in milliseconds, including any
 310                                          * unfinished recovery.
 311                                          */
 312 };
 313
 314 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
 315 enum {
 316         TCP_NLA_PAD,
 317         TCP_NLA_BUSY,           /* Time (usec) busy sending data */
 318         TCP_NLA_RWND_LIMITED,   /* Time (usec) limited by receive window */
 319         TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
 320         TCP_NLA_DATA_SEGS_OUT,  /* Data pkts sent including retransmission */
 321         TCP_NLA_TOTAL_RETRANS,  /* Data pkts retransmitted */
 322         TCP_NLA_PACING_RATE,    /* Pacing rate in bytes per second */
 323         TCP_NLA_DELIVERY_RATE,  /* Delivery rate in bytes per second */
 324         TCP_NLA_SND_CWND,       /* Sending congestion window */
 325         TCP_NLA_REORDERING,     /* Reordering metric */
 326         TCP_NLA_MIN_RTT,        /* minimum RTT */
 327         TCP_NLA_RECUR_RETRANS,  /* Recurring retransmits for the current pkt */
 328         TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
 329         TCP_NLA_SNDQ_SIZE,      /* Data (bytes) pending in send queue */
 330         TCP_NLA_CA_STATE,       /* ca_state of socket */
 331         TCP_NLA_SND_SSTHRESH,   /* Slow start size threshold */
 332         TCP_NLA_DELIVERED,      /* Data pkts delivered incl. out-of-order */
 333         TCP_NLA_DELIVERED_CE,   /* Like above but only ones w/ CE marks */
 334         TCP_NLA_BYTES_SENT,     /* Data bytes sent including retransmission */
 335         TCP_NLA_BYTES_RETRANS,  /* Data bytes retransmitted */
 336         TCP_NLA_DSACK_DUPS,     /* DSACK blocks received */
 337         TCP_NLA_REORD_SEEN,     /* reordering events seen */
 338         TCP_NLA_SRTT,           /* smoothed RTT in usecs */
 339         TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
 340         TCP_NLA_BYTES_NOTSENT,  /* Bytes in write queue not yet sent */
 341         TCP_NLA_EDT,            /* Earliest departure time (CLOCK_MONOTONIC) */
 342         TCP_NLA_TTL,            /* TTL or hop limit of a packet received */
 343         TCP_NLA_REHASH,         /* PLB and timeout triggered rehash attempts */
 344 };
 345
 346 /* for TCP_MD5SIG socket option */
 347 #define TCP_MD5SIG_MAXKEYLEN    80
 348
 349 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
 350 #define TCP_MD5SIG_FLAG_PREFIX          0x1     /* address prefix length */
 351 #define TCP_MD5SIG_FLAG_IFINDEX         0x2     /* ifindex set */
 352
 353 struct tcp_md5sig {
 354         struct __kernel_sockaddr_storage tcpm_addr;     /* address associated */
 355         __u8    tcpm_flags;                             /* extension flags */
 356         __u8    tcpm_prefixlen;                         /* address prefix */
 357         __u16   tcpm_keylen;                            /* key length */
 358         int     tcpm_ifindex;                           /* device index for scope */
 359         __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];         /* key (binary) */
 360 };
 361
 362 /* INET_DIAG_MD5SIG */
 363 struct tcp_diag_md5sig {
 364         __u8    tcpm_family;
 365         __u8    tcpm_prefixlen;
 366         __u16   tcpm_keylen;
 367         __be32  tcpm_addr[4];
 368         __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];
 369 };
 370
 371 #define TCP_AO_MAXKEYLEN        80
 372
 373 #define TCP_AO_KEYF_IFINDEX     (1 << 0)        /* L3 ifindex for VRF */
 374 #define TCP_AO_KEYF_EXCLUDE_OPT (1 << 1)        /* "Indicates whether TCP
 375                                                  *  options other than TCP-AO
 376                                                  *  are included in the MAC
 377                                                  *  calculation"
 378                                                  */
 379
 380 struct tcp_ao_add { /* setsockopt(TCP_AO_ADD_KEY) */
 381         struct __kernel_sockaddr_storage addr;  /* peer's address for the key */
 382         char    alg_name[64];           /* crypto hash algorithm to use */
 383         __s32   ifindex;                /* L3 dev index for VRF */
 384         __u32   set_current     :1,     /* set key as Current_key at once */
 385                 set_rnext       :1,     /* request it from peer with RNext_key */
 386                 reserved        :30;    /* must be 0 */
 387         __u16   reserved2;              /* padding, must be 0 */
 388         __u8    prefix;                 /* peer's address prefix */
 389         __u8    sndid;                  /* SendID for outgoing segments */
 390         __u8    rcvid;                  /* RecvID to match for incoming seg */
 391         __u8    maclen;                 /* length of authentication code (hash) */
 392         __u8    keyflags;               /* see TCP_AO_KEYF_ */
 393         __u8    keylen;                 /* length of ::key */
 394         __u8    key[TCP_AO_MAXKEYLEN];
 395 } __attribute__((aligned(8)));
 396
 397 struct tcp_ao_del { /* setsockopt(TCP_AO_DEL_KEY) */
 398         struct __kernel_sockaddr_storage addr;  /* peer's address for the key */
 399         __s32   ifindex;                /* L3 dev index for VRF */
 400         __u32   set_current     :1,     /* corresponding ::current_key */
 401                 set_rnext       :1,     /* corresponding ::rnext */
 402                 del_async       :1,     /* only valid for listen sockets */
 403                 reserved        :29;    /* must be 0 */
 404         __u16   reserved2;              /* padding, must be 0 */
 405         __u8    prefix;                 /* peer's address prefix */
 406         __u8    sndid;                  /* SendID for outgoing segments */
 407         __u8    rcvid;                  /* RecvID to match for incoming seg */
 408         __u8    current_key;            /* KeyID to set as Current_key */
 409         __u8    rnext;                  /* KeyID to set as Rnext_key */
 410         __u8    keyflags;               /* see TCP_AO_KEYF_ */
 411 } __attribute__((aligned(8)));
 412
 413 struct tcp_ao_info_opt { /* setsockopt(TCP_AO_INFO), getsockopt(TCP_AO_INFO) */
 414         /* Here 'in' is for setsockopt(), 'out' is for getsockopt() */
 415         __u32   set_current     :1,     /* in/out: corresponding ::current_key */
 416                 set_rnext       :1,     /* in/out: corresponding ::rnext */
 417                 ao_required     :1,     /* in/out: don't accept non-AO connects */
 418                 set_counters    :1,     /* in: set/clear ::pkt_* counters */
 419                 accept_icmps    :1,     /* in/out: accept incoming ICMPs */
 420                 reserved        :27;    /* must be 0 */
 421         __u16   reserved2;              /* padding, must be 0 */
 422         __u8    current_key;            /* in/out: KeyID of Current_key */
 423         __u8    rnext;                  /* in/out: keyid of RNext_key */
 424         __u64   pkt_good;               /* in/out: verified segments */
 425         __u64   pkt_bad;                /* in/out: failed verification */
 426         __u64   pkt_key_not_found;      /* in/out: could not find a key to verify */
 427         __u64   pkt_ao_required;        /* in/out: segments missing TCP-AO sign */
 428         __u64   pkt_dropped_icmp;       /* in/out: ICMPs that were ignored */
 429 } __attribute__((aligned(8)));
 430
 431 struct tcp_ao_getsockopt { /* getsockopt(TCP_AO_GET_KEYS) */
 432         struct __kernel_sockaddr_storage addr;  /* in/out: dump keys for peer
 433                                                  * with this address/prefix
 434                                                  */
 435         char    alg_name[64];           /* out: crypto hash algorithm */
 436         __u8    key[TCP_AO_MAXKEYLEN];
 437         __u32   nkeys;                  /* in: size of the userspace buffer
 438                                          * @optval, measured in @optlen - the
 439                                          * sizeof(struct tcp_ao_getsockopt)
 440                                          * out: number of keys that matched
 441                                          */
 442         __u16   is_current      :1,     /* in: match and dump Current_key,
 443                                          * out: the dumped key is Current_key
 444                                          */
 445
 446                 is_rnext        :1,     /* in: match and dump RNext_key,
 447                                          * out: the dumped key is RNext_key
 448                                          */
 449                 get_all         :1,     /* in: dump all keys */
 450                 reserved        :13;    /* padding, must be 0 */
 451         __u8    sndid;                  /* in/out: dump keys with SendID */
 452         __u8    rcvid;                  /* in/out: dump keys with RecvID */
 453         __u8    prefix;                 /* in/out: dump keys with address/prefix */
 454         __u8    maclen;                 /* out: key's length of authentication
 455                                          * code (hash)
 456                                          */
 457         __u8    keyflags;               /* in/out: see TCP_AO_KEYF_ */
 458         __u8    keylen;                 /* out: length of ::key */
 459         __s32   ifindex;                /* in/out: L3 dev index for VRF */
 460         __u64   pkt_good;               /* out: verified segments */
 461         __u64   pkt_bad;                /* out: segments that failed verification */
 462 } __attribute__((aligned(8)));
 463
 464 struct tcp_ao_repair { /* {s,g}etsockopt(TCP_AO_REPAIR) */
 465         __be32                  snt_isn;
 466         __be32                  rcv_isn;
 467         __u32                   snd_sne;
 468         __u32                   rcv_sne;
 469 } __attribute__((aligned(8)));
 470
 471 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
 472
 473 #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
 474 struct tcp_zerocopy_receive {
 475         __u64 address;          /* in: address of mapping */
 476         __u32 length;           /* in/out: number of bytes to map/mapped */
 477         __u32 recv_skip_hint;   /* out: amount of bytes to skip */
 478         __u32 inq; /* out: amount of bytes in read queue */
 479         __s32 err; /* out: socket error */
 480         __u64 copybuf_address;  /* in: copybuf address (small reads) */
 481         __s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
 482         __u32 flags; /* in: flags */
 483         __u64 msg_control; /* ancillary data */
 484         __u64 msg_controllen;
 485         __u32 msg_flags;
 486         __u32 reserved; /* set to 0 for now */
 487 };
 488 #endif /* _UAPI_LINUX_TCP_H */