The C and C++ Include Header Files

/usr/include/linux/tcp.h


$ cat -n /usr/include/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 _LINUX_TCP_H
    19	#define _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_REPAIR_ON		1
   139	#define TCP_REPAIR_OFF		0
   140	#define TCP_REPAIR_OFF_NO_WP	-1	/* Turn off without window probes */
   141	
   142	struct tcp_repair_opt {
   143		__u32	opt_code;
   144		__u32	opt_val;
   145	};
   146	
   147	struct tcp_repair_window {
   148		__u32	snd_wl1;
   149		__u32	snd_wnd;
   150		__u32	max_window;
   151	
   152		__u32	rcv_wnd;
   153		__u32	rcv_wup;
   154	};
   155	
   156	enum {
   157		TCP_NO_QUEUE,
   158		TCP_RECV_QUEUE,
   159		TCP_SEND_QUEUE,
   160		TCP_QUEUES_NR,
   161	};
   162	
   163	/* why fastopen failed from client perspective */
   164	enum tcp_fastopen_client_fail {
   165		TFO_STATUS_UNSPEC, /* catch-all */
   166		TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
   167		TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
   168		TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
   169	};
   170	
   171	/* for TCP_INFO socket option */
   172	#define TCPI_OPT_TIMESTAMPS	1
   173	#define TCPI_OPT_SACK		2
   174	#define TCPI_OPT_WSCALE		4
   175	#define TCPI_OPT_ECN		8 /* ECN was negociated at TCP session init */
   176	#define TCPI_OPT_ECN_SEEN	16 /* we received at least one packet with ECT */
   177	#define TCPI_OPT_SYN_DATA	32 /* SYN-ACK acked data in SYN sent or rcvd */
   178	#define TCPI_OPT_USEC_TS	64 /* usec timestamps */
   179	
   180	/*
   181	 * Sender's congestion state indicating normal or abnormal situations
   182	 * in the last round of packets sent. The state is driven by the ACK
   183	 * information and timer events.
   184	 */
   185	enum tcp_ca_state {
   186		/*
   187		 * Nothing bad has been observed recently.
   188		 * No apparent reordering, packet loss, or ECN marks.
   189		 */
   190		TCP_CA_Open = 0,
   191	#define TCPF_CA_Open	(1<<TCP_CA_Open)
   192		/*
   193		 * The sender enters disordered state when it has received DUPACKs or
   194		 * SACKs in the last round of packets sent. This could be due to packet
   195		 * loss or reordering but needs further information to confirm packets
   196		 * have been lost.
   197		 */
   198		TCP_CA_Disorder = 1,
   199	#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
   200		/*
   201		 * The sender enters Congestion Window Reduction (CWR) state when it
   202		 * has received ACKs with ECN-ECE marks, or has experienced congestion
   203		 * or packet discard on the sender host (e.g. qdisc).
   204		 */
   205		TCP_CA_CWR = 2,
   206	#define TCPF_CA_CWR	(1<<TCP_CA_CWR)
   207		/*
   208		 * The sender is in fast recovery and retransmitting lost packets,
   209		 * typically triggered by ACK events.
   210		 */
   211		TCP_CA_Recovery = 3,
   212	#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
   213		/*
   214		 * The sender is in loss recovery triggered by retransmission timeout.
   215		 */
   216		TCP_CA_Loss = 4
   217	#define TCPF_CA_Loss	(1<<TCP_CA_Loss)
   218	};
   219	
   220	struct tcp_info {
   221		__u8	tcpi_state;
   222		__u8	tcpi_ca_state;
   223		__u8	tcpi_retransmits;
   224		__u8	tcpi_probes;
   225		__u8	tcpi_backoff;
   226		__u8	tcpi_options;
   227		__u8	tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
   228		__u8	tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
   229	
   230		__u32	tcpi_rto;
   231		__u32	tcpi_ato;
   232		__u32	tcpi_snd_mss;
   233		__u32	tcpi_rcv_mss;
   234	
   235		__u32	tcpi_unacked;
   236		__u32	tcpi_sacked;
   237		__u32	tcpi_lost;
   238		__u32	tcpi_retrans;
   239		__u32	tcpi_fackets;
   240	
   241		/* Times. */
   242		__u32	tcpi_last_data_sent;
   243		__u32	tcpi_last_ack_sent;     /* Not remembered, sorry. */
   244		__u32	tcpi_last_data_recv;
   245		__u32	tcpi_last_ack_recv;
   246	
   247		/* Metrics. */
   248		__u32	tcpi_pmtu;
   249		__u32	tcpi_rcv_ssthresh;
   250		__u32	tcpi_rtt;
   251		__u32	tcpi_rttvar;
   252		__u32	tcpi_snd_ssthresh;
   253		__u32	tcpi_snd_cwnd;
   254		__u32	tcpi_advmss;
   255		__u32	tcpi_reordering;
   256	
   257		__u32	tcpi_rcv_rtt;
   258		__u32	tcpi_rcv_space;
   259	
   260		__u32	tcpi_total_retrans;
   261	
   262		__u64	tcpi_pacing_rate;
   263		__u64	tcpi_max_pacing_rate;
   264		__u64	tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
   265		__u64	tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
   266		__u32	tcpi_segs_out;	     /* RFC4898 tcpEStatsPerfSegsOut */
   267		__u32	tcpi_segs_in;	     /* RFC4898 tcpEStatsPerfSegsIn */
   268	
   269		__u32	tcpi_notsent_bytes;
   270		__u32	tcpi_min_rtt;
   271		__u32	tcpi_data_segs_in;	/* RFC4898 tcpEStatsDataSegsIn */
   272		__u32	tcpi_data_segs_out;	/* RFC4898 tcpEStatsDataSegsOut */
   273	
   274		__u64   tcpi_delivery_rate;
   275	
   276		__u64	tcpi_busy_time;      /* Time (usec) busy sending data */
   277		__u64	tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
   278		__u64	tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
   279	
   280		__u32	tcpi_delivered;
   281		__u32	tcpi_delivered_ce;
   282	
   283		__u64	tcpi_bytes_sent;     /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
   284		__u64	tcpi_bytes_retrans;  /* RFC4898 tcpEStatsPerfOctetsRetrans */
   285		__u32	tcpi_dsack_dups;     /* RFC4898 tcpEStatsStackDSACKDups */
   286		__u32	tcpi_reord_seen;     /* reordering events seen */
   287	
   288		__u32	tcpi_rcv_ooopack;    /* Out-of-order packets received */
   289	
   290		__u32	tcpi_snd_wnd;	     /* peer's advertised receive window after
   291					      * scaling (bytes)
   292					      */
   293		__u32	tcpi_rcv_wnd;	     /* local advertised receive window after
   294					      * scaling (bytes)
   295					      */
   296	
   297		__u32   tcpi_rehash;         /* PLB or timeout triggered rehash attempts */
   298	
   299		__u16	tcpi_total_rto;	/* Total number of RTO timeouts, including
   300					 * SYN/SYN-ACK and recurring timeouts.
   301					 */
   302		__u16	tcpi_total_rto_recoveries;	/* Total number of RTO
   303							 * recoveries, including any
   304							 * unfinished recovery.
   305							 */
   306		__u32	tcpi_total_rto_time;	/* Total time spent in RTO recoveries
   307						 * in milliseconds, including any
   308						 * unfinished recovery.
   309						 */
   310	};
   311	
   312	/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
   313	enum {
   314		TCP_NLA_PAD,
   315		TCP_NLA_BUSY,		/* Time (usec) busy sending data */
   316		TCP_NLA_RWND_LIMITED,	/* Time (usec) limited by receive window */
   317		TCP_NLA_SNDBUF_LIMITED,	/* Time (usec) limited by send buffer */
   318		TCP_NLA_DATA_SEGS_OUT,	/* Data pkts sent including retransmission */
   319		TCP_NLA_TOTAL_RETRANS,	/* Data pkts retransmitted */
   320		TCP_NLA_PACING_RATE,    /* Pacing rate in bytes per second */
   321		TCP_NLA_DELIVERY_RATE,  /* Delivery rate in bytes per second */
   322		TCP_NLA_SND_CWND,       /* Sending congestion window */
   323		TCP_NLA_REORDERING,     /* Reordering metric */
   324		TCP_NLA_MIN_RTT,        /* minimum RTT */
   325		TCP_NLA_RECUR_RETRANS,  /* Recurring retransmits for the current pkt */
   326		TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
   327		TCP_NLA_SNDQ_SIZE,	/* Data (bytes) pending in send queue */
   328		TCP_NLA_CA_STATE,	/* ca_state of socket */
   329		TCP_NLA_SND_SSTHRESH,	/* Slow start size threshold */
   330		TCP_NLA_DELIVERED,	/* Data pkts delivered incl. out-of-order */
   331		TCP_NLA_DELIVERED_CE,	/* Like above but only ones w/ CE marks */
   332		TCP_NLA_BYTES_SENT,	/* Data bytes sent including retransmission */
   333		TCP_NLA_BYTES_RETRANS,	/* Data bytes retransmitted */
   334		TCP_NLA_DSACK_DUPS,	/* DSACK blocks received */
   335		TCP_NLA_REORD_SEEN,	/* reordering events seen */
   336		TCP_NLA_SRTT,		/* smoothed RTT in usecs */
   337		TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
   338		TCP_NLA_BYTES_NOTSENT,	/* Bytes in write queue not yet sent */
   339		TCP_NLA_EDT,		/* Earliest departure time (CLOCK_MONOTONIC) */
   340		TCP_NLA_TTL,		/* TTL or hop limit of a packet received */
   341		TCP_NLA_REHASH,         /* PLB and timeout triggered rehash attempts */
   342	};
   343	
   344	/* for TCP_MD5SIG socket option */
   345	#define TCP_MD5SIG_MAXKEYLEN	80
   346	
   347	/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
   348	#define TCP_MD5SIG_FLAG_PREFIX		0x1	/* address prefix length */
   349	#define TCP_MD5SIG_FLAG_IFINDEX		0x2	/* ifindex set */
   350	
   351	struct tcp_md5sig {
   352		struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
   353		__u8	tcpm_flags;				/* extension flags */
   354		__u8	tcpm_prefixlen;				/* address prefix */
   355		__u16	tcpm_keylen;				/* key length */
   356		int	tcpm_ifindex;				/* device index for scope */
   357		__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];		/* key (binary) */
   358	};
   359	
   360	/* INET_DIAG_MD5SIG */
   361	struct tcp_diag_md5sig {
   362		__u8	tcpm_family;
   363		__u8	tcpm_prefixlen;
   364		__u16	tcpm_keylen;
   365		__be32	tcpm_addr[4];
   366		__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];
   367	};
   368	
   369	#define TCP_AO_MAXKEYLEN	80
   370	
   371	#define TCP_AO_KEYF_IFINDEX	(1 << 0)	/* L3 ifindex for VRF */
   372	#define TCP_AO_KEYF_EXCLUDE_OPT	(1 << 1)	/* "Indicates whether TCP
   373							 *  options other than TCP-AO
   374							 *  are included in the MAC
   375							 *  calculation"
   376							 */
   377	
   378	struct tcp_ao_add { /* setsockopt(TCP_AO_ADD_KEY) */
   379		struct __kernel_sockaddr_storage addr;	/* peer's address for the key */
   380		char	alg_name[64];		/* crypto hash algorithm to use */
   381		__s32	ifindex;		/* L3 dev index for VRF */
   382		__u32   set_current	:1,	/* set key as Current_key at once */
   383			set_rnext	:1,	/* request it from peer with RNext_key */
   384			reserved	:30;	/* must be 0 */
   385		__u16	reserved2;		/* padding, must be 0 */
   386		__u8	prefix;			/* peer's address prefix */
   387		__u8	sndid;			/* SendID for outgoing segments */
   388		__u8	rcvid;			/* RecvID to match for incoming seg */
   389		__u8	maclen;			/* length of authentication code (hash) */
   390		__u8	keyflags;		/* see TCP_AO_KEYF_ */
   391		__u8	keylen;			/* length of ::key */
   392		__u8	key[TCP_AO_MAXKEYLEN];
   393	} __attribute__((aligned(8)));
   394	
   395	struct tcp_ao_del { /* setsockopt(TCP_AO_DEL_KEY) */
   396		struct __kernel_sockaddr_storage addr;	/* peer's address for the key */
   397		__s32	ifindex;		/* L3 dev index for VRF */
   398		__u32   set_current	:1,	/* corresponding ::current_key */
   399			set_rnext	:1,	/* corresponding ::rnext */
   400			del_async	:1,	/* only valid for listen sockets */
   401			reserved	:29;	/* must be 0 */
   402		__u16	reserved2;		/* padding, must be 0 */
   403		__u8	prefix;			/* peer's address prefix */
   404		__u8	sndid;			/* SendID for outgoing segments */
   405		__u8	rcvid;			/* RecvID to match for incoming seg */
   406		__u8	current_key;		/* KeyID to set as Current_key */
   407		__u8	rnext;			/* KeyID to set as Rnext_key */
   408		__u8	keyflags;		/* see TCP_AO_KEYF_ */
   409	} __attribute__((aligned(8)));
   410	
   411	struct tcp_ao_info_opt { /* setsockopt(TCP_AO_INFO), getsockopt(TCP_AO_INFO) */
   412		/* Here 'in' is for setsockopt(), 'out' is for getsockopt() */
   413		__u32   set_current	:1,	/* in/out: corresponding ::current_key */
   414			set_rnext	:1,	/* in/out: corresponding ::rnext */
   415			ao_required	:1,	/* in/out: don't accept non-AO connects */
   416			set_counters	:1,	/* in: set/clear ::pkt_* counters */
   417			accept_icmps	:1,	/* in/out: accept incoming ICMPs */
   418			reserved	:27;	/* must be 0 */
   419		__u16	reserved2;		/* padding, must be 0 */
   420		__u8	current_key;		/* in/out: KeyID of Current_key */
   421		__u8	rnext;			/* in/out: keyid of RNext_key */
   422		__u64	pkt_good;		/* in/out: verified segments */
   423		__u64	pkt_bad;		/* in/out: failed verification */
   424		__u64	pkt_key_not_found;	/* in/out: could not find a key to verify */
   425		__u64	pkt_ao_required;	/* in/out: segments missing TCP-AO sign */
   426		__u64	pkt_dropped_icmp;	/* in/out: ICMPs that were ignored */
   427	} __attribute__((aligned(8)));
   428	
   429	struct tcp_ao_getsockopt { /* getsockopt(TCP_AO_GET_KEYS) */
   430		struct __kernel_sockaddr_storage addr;	/* in/out: dump keys for peer
   431							 * with this address/prefix
   432							 */
   433		char	alg_name[64];		/* out: crypto hash algorithm */
   434		__u8	key[TCP_AO_MAXKEYLEN];
   435		__u32	nkeys;			/* in: size of the userspace buffer
   436						 * @optval, measured in @optlen - the
   437						 * sizeof(struct tcp_ao_getsockopt)
   438						 * out: number of keys that matched
   439						 */
   440		__u16   is_current	:1,	/* in: match and dump Current_key,
   441						 * out: the dumped key is Current_key
   442						 */
   443	
   444			is_rnext	:1,	/* in: match and dump RNext_key,
   445						 * out: the dumped key is RNext_key
   446						 */
   447			get_all		:1,	/* in: dump all keys */
   448			reserved	:13;	/* padding, must be 0 */
   449		__u8	sndid;			/* in/out: dump keys with SendID */
   450		__u8	rcvid;			/* in/out: dump keys with RecvID */
   451		__u8	prefix;			/* in/out: dump keys with address/prefix */
   452		__u8	maclen;			/* out: key's length of authentication
   453						 * code (hash)
   454						 */
   455		__u8	keyflags;		/* in/out: see TCP_AO_KEYF_ */
   456		__u8	keylen;			/* out: length of ::key */
   457		__s32	ifindex;		/* in/out: L3 dev index for VRF */
   458		__u64	pkt_good;		/* out: verified segments */
   459		__u64	pkt_bad;		/* out: segments that failed verification */
   460	} __attribute__((aligned(8)));
   461	
   462	struct tcp_ao_repair { /* {s,g}etsockopt(TCP_AO_REPAIR) */
   463		__be32			snt_isn;
   464		__be32			rcv_isn;
   465		__u32			snd_sne;
   466		__u32			rcv_sne;
   467	} __attribute__((aligned(8)));
   468	
   469	/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
   470	
   471	#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
   472	struct tcp_zerocopy_receive {
   473		__u64 address;		/* in: address of mapping */
   474		__u32 length;		/* in/out: number of bytes to map/mapped */
   475		__u32 recv_skip_hint;	/* out: amount of bytes to skip */
   476		__u32 inq; /* out: amount of bytes in read queue */
   477		__s32 err; /* out: socket error */
   478		__u64 copybuf_address;	/* in: copybuf address (small reads) */
   479		__s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
   480		__u32 flags; /* in: flags */
   481		__u64 msg_control; /* ancillary data */
   482		__u64 msg_controllen;
   483		__u32 msg_flags;
   484		__u32 reserved; /* set to 0 for now */
   485	};
   486	#endif /* _LINUX_TCP_H */