in.h(0p)

1<netinet/in.h>(P)          POSIX Programmer's Manual         <netinet/in.h>(P)
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NAME

6       netinet/in.h - Internet address family
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SYNOPSIS

9       #include <netinet/in.h>
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DESCRIPTION

12       The <netinet/in.h> header shall define the following types:
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14       in_port_t
15              Equivalent to the type uint16_t as defined in <inttypes.h> .
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17       in_addr_t
18              Equivalent to the type uint32_t as defined in <inttypes.h> .
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21       The sa_family_t type shall be defined as described in <sys/socket.h> .
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23       The  uint8_t  and  uint32_t type shall be defined as described in <int‐
24       types.h>. Inclusion of the <netinet/in.h> header may also make  visible
25       all symbols from <inttypes.h> and <sys/socket.h>.
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27       The  <netinet/in.h>  header  shall  define  the  in_addr structure that
28       includes at least the following member:
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31              in_addr_t  s_addr
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33       The <netinet/in.h> header shall define the sockaddr_in  structure  that
34       includes at least the following members (all in network byte order):
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37              sa_family_t     sin_family   AF_INET.
38              in_port_t       sin_port     Port number.
39              struct in_addr  sin_addr     IP address.
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41       The  sockaddr_in  structure is used to store addresses for the Internet
42       address family. Values of this type shall be cast  by  applications  to
43       struct sockaddr for use with socket functions.
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45       The <netinet/in.h> header shall define the in6_addr structure that con‐
46       tains at least the following member:
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49              uint8_t s6_addr[16]
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51       This array is used to contain a 128-bit IPv6 address, stored in network
52       byte order.
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54       The  <netinet/in.h> header shall define the sockaddr_in6 structure that
55       includes at least the following members (all in network byte order):
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58              sa_family_t      sin6_family    AF_INET6.
59              in_port_t        sin6_port      Port number.
60              uint32_t         sin6_flowinfo  IPv6 traffic class and flow information.
61              struct in6_addr  sin6_addr      IPv6 address.
62              uint32_t         sin6_scope_id  Set of interfaces for a scope.
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64       The sockaddr_in6 structure shall be set to zero by an application prior
65       to  using it, since implementations are free to have additional, imple‐
66       mentation-defined fields in sockaddr_in6.
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68       The sin6_scope_id field is a 32-bit integer that identifies  a  set  of
69       interfaces  as  appropriate for the scope of the address carried in the
70       sin6_addr field. For a link  scope  sin6_addr,  the  application  shall
71       ensure  that sin6_scope_id is a link index. For a site scope sin6_addr,
72       the application shall ensure that sin6_scope_id is a  site  index.  The
73       mapping of sin6_scope_id to an interface or set of interfaces is imple‐
74       mentation-defined.
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76       The <netinet/in.h> header shall declare the  following  external  vari‐
77       able:
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80              const struct in6_addr in6addr_any
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82       This variable is initialized by the system to contain the wildcard IPv6
83       address. The <netinet/in.h> header also  defines  the  IN6ADDR_ANY_INIT
84       macro.  This  macro must be constant at compile time and can be used to
85       initialize a variable of type struct  in6_addr  to  the  IPv6  wildcard
86       address.
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88       The  <netinet/in.h>  header  shall declare the following external vari‐
89       able:
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91
92              const struct in6_addr in6addr_loopback
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94       This variable is initialized by the system to contain the loopback IPv6
95       address.  The  <netinet/in.h>  header  also  defines  the IN6ADDR_LOOP‐
96       BACK_INIT macro. This macro must be constant at compile time and can be
97       used to initialize a variable of type struct in6_addr to the IPv6 loop‐
98       back address.
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100       The <netinet/in.h> header shall define  the  ipv6_mreq  structure  that
101       includes at least the following members:
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104              struct in6_addr  ipv6mr_multiaddr  IPv6 multicast address.
105              unsigned         ipv6mr_interface  Interface index.
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107       The  <netinet/in.h> header shall define the following macros for use as
108       values of the level argument of getsockopt() and setsockopt():
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110       IPPROTO_IP
111              Internet protocol.
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113       IPPROTO_IPV6
114              Internet Protocol Version 6.
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116       IPPROTO_ICMP
117              Control message protocol.
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119       IPPROTO_RAW
120              Raw IP Packets Protocol.
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122       IPPROTO_TCP
123              Transmission control protocol.
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125       IPPROTO_UDP
126              User datagram protocol.
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129       The <netinet/in.h> header shall define the following macros for use  as
130       destination addresses for connect(), sendmsg(), and sendto():
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132       INADDR_ANY
133              IPv4 local host address.
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135       INADDR_BROADCAST
136              IPv4 broadcast address.
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139       The  <netinet/in.h>  header  shall  define  the following macro to help
140       applications declare buffers of the proper size to store IPv4 addresses
141       in string form:
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143       INET_ADDRSTRLEN
144              16. Length of the string form for IP.
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147       The htonl(), htons(), ntohl(), and ntohs() functions shall be available
148       as defined in <arpa/inet.h> . Inclusion of  the  <netinet/in.h>  header
149       may also make visible all symbols from <arpa/inet.h> .
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151       The  <netinet/in.h>  header  shall  define  the following macro to help
152       applications declare buffers of the proper size to store IPv6 addresses
153       in string form:
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155       INET6_ADDRSTRLEN
156              46. Length of the string form for IPv6.
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159       The  <netinet/in.h> header shall define the following macros, with dis‐
160       tinct integer values, for use in the option_name argument in  the  get‐
161       sockopt() or setsockopt() functions at protocol level IPPROTO_IPV6:
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163       IPV6_JOIN_GROUP
164              Join a multicast group.
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166       IPV6_LEAVE_GROUP
167              Quit a multicast group.
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169       IPV6_MULTICAST_HOPS
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171              Multicast hop limit.
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173       IPV6_MULTICAST_IF
174              Interface to use for outgoing multicast packets.
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176       IPV6_MULTICAST_LOOP
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178              Multicast packets are delivered back to the local application.
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180       IPV6_UNICAST_HOPS
181              Unicast hop limit.
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183       IPV6_V6ONLY
184              Restrict AF_INET6 socket to IPv6 communications only.
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186
187       The  <netinet/in.h>  header shall define the following macros that test
188       for special IPv6 addresses. Each macro is of type int and takes a  sin‐
189       gle argument of type const struct in6_addr *:
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191       IN6_IS_ADDR_UNSPECIFIED
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193              Unspecified address.
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195       IN6_IS_ADDR_LOOPBACK
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197              Loopback address.
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199       IN6_IS_ADDR_MULTICAST
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201              Multicast address.
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203       IN6_IS_ADDR_LINKLOCAL
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205              Unicast link-local address.
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207       IN6_IS_ADDR_SITELOCAL
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209              Unicast site-local address.
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211       IN6_IS_ADDR_V4MAPPED
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213              IPv4 mapped address.
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215       IN6_IS_ADDR_V4COMPAT
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217              IPv4-compatible address.
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219       IN6_IS_ADDR_MC_NODELOCAL
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221              Multicast node-local address.
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223       IN6_IS_ADDR_MC_LINKLOCAL
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225              Multicast link-local address.
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227       IN6_IS_ADDR_MC_SITELOCAL
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229              Multicast site-local address.
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231       IN6_IS_ADDR_MC_ORGLOCAL
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233              Multicast organization-local address.
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235       IN6_IS_ADDR_MC_GLOBAL
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237              Multicast global address.
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240       The following sections are informative.
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APPLICATION USAGE

243       None.
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RATIONALE

246       None.
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FUTURE DIRECTIONS

249       None.
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COPYRIGHT

258       Portions of this text are reprinted and reproduced in  electronic  form
259       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
260       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
261       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
262       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
263       event of any discrepancy between this version and the original IEEE and
264       The Open Group Standard, the original IEEE and The Open Group  Standard
265       is  the  referee document. The original Standard can be obtained online
266       at http://www.opengroup.org/unix/online.html .
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270IEEE/The Open Group                  2003                    <netinet/in.h>(P)