<netinet/in.h>(0P)                                  POSIX Programmer's Manual                                 <netinet/in.h>(0P)



NAME
       netinet/in.h - Internet address family

SYNOPSIS
       #include <netinet/in.h>

DESCRIPTION
       The <netinet/in.h> header shall define the following types:

       in_port_t
              Equivalent to the type uint16_t as defined in <inttypes.h> .

       in_addr_t
              Equivalent to the type uint32_t as defined in <inttypes.h> .


       The sa_family_t type shall be defined as described in <sys/socket.h> .

       The  uint8_t  and uint32_t type shall be defined as described in <inttypes.h>. Inclusion of the <netinet/in.h> header may
       also make visible all symbols from <inttypes.h> and <sys/socket.h>.

       The <netinet/in.h> header shall define the in_addr structure that includes at least the following member:


              in_addr_t  s_addr

       The <netinet/in.h> header shall define the sockaddr_in structure that includes at least the  following  members  (all  in
       network byte order):


              sa_family_t     sin_family   AF_INET.
              in_port_t       sin_port     Port number.
              struct in_addr  sin_addr     IP address.

       The  sockaddr_in  structure is used to store addresses for the Internet address family. Values of this type shall be cast
       by applications to struct sockaddr for use with socket functions.

       The <netinet/in.h> header shall define the in6_addr structure that contains at least the following member:


              uint8_t s6_addr[16]

       This array is used to contain a 128-bit IPv6 address, stored in network byte order.

       The <netinet/in.h> header shall define the sockaddr_in6 structure that includes at least the following  members  (all  in
       network byte order):


              sa_family_t      sin6_family    AF_INET6.
              in_port_t        sin6_port      Port number.
              uint32_t         sin6_flowinfo  IPv6 traffic class and flow information.
              struct in6_addr  sin6_addr      IPv6 address.
              uint32_t         sin6_scope_id  Set of interfaces for a scope.

       The  sockaddr_in6  structure  shall be set to zero by an application prior to using it, since implementations are free to
       have additional, implementation-defined fields in sockaddr_in6.

       The sin6_scope_id field is a 32-bit integer that identifies a set of interfaces as  appropriate  for  the  scope  of  the
       address  carried in the sin6_addr field. For a link scope sin6_addr, the application shall ensure that sin6_scope_id is a
       link index. For a site scope sin6_addr, the application shall ensure that sin6_scope_id is a site index. The  mapping  of
       sin6_scope_id to an interface or set of interfaces is implementation-defined.

       The <netinet/in.h> header shall declare the following external variable:


              const struct in6_addr in6addr_any

       This  variable  is initialized by the system to contain the wildcard IPv6 address. The <netinet/in.h> header also defines
       the IN6ADDR_ANY_INIT macro. This macro must be constant at compile time and can be used to initialize a variable of  type
       struct in6_addr to the IPv6 wildcard address.

       The <netinet/in.h> header shall declare the following external variable:


              const struct in6_addr in6addr_loopback

       This  variable  is initialized by the system to contain the loopback IPv6 address. The <netinet/in.h> header also defines
       the IN6ADDR_LOOPBACK_INIT macro. This macro must be constant at compile time and can be used to initialize a variable  of
       type struct in6_addr to the IPv6 loopback address.

       The <netinet/in.h> header shall define the ipv6_mreq structure that includes at least the following members:


              struct in6_addr  ipv6mr_multiaddr  IPv6 multicast address.
              unsigned         ipv6mr_interface  Interface index.

       The  <netinet/in.h>  header shall define the following macros for use as values of the level argument of getsockopt() and
       setsockopt():

       IPPROTO_IP
              Internet protocol.

       IPPROTO_IPV6
              Internet Protocol Version 6.

       IPPROTO_ICMP
              Control message protocol.

       IPPROTO_RAW
              Raw IP Packets Protocol.

       IPPROTO_TCP
              Transmission control protocol.

       IPPROTO_UDP
              User datagram protocol.


       The <netinet/in.h> header shall define the following macros for use as destination addresses  for  connect(),  sendmsg(),
       and sendto():

       INADDR_ANY
              IPv4 local host address.

       INADDR_BROADCAST
              IPv4 broadcast address.


       The  <netinet/in.h>  header  shall  define the following macro to help applications declare buffers of the proper size to
       store IPv4 addresses in string form:

       INET_ADDRSTRLEN
              16. Length of the string form for IP.


       The htonl(), htons(), ntohl(), and ntohs() functions shall be available as defined in <arpa/inet.h> .  Inclusion  of  the
       <netinet/in.h> header may also make visible all symbols from <arpa/inet.h> .

       The  <netinet/in.h>  header  shall  define the following macro to help applications declare buffers of the proper size to
       store IPv6 addresses in string form:

       INET6_ADDRSTRLEN
              46. Length of the string form for IPv6.


       The <netinet/in.h> header shall define the following macros, with distinct integer values, for  use  in  the  option_name
       argument in the getsockopt() or setsockopt() functions at protocol level IPPROTO_IPV6:

       IPV6_JOIN_GROUP
              Join a multicast group.

       IPV6_LEAVE_GROUP
              Quit a multicast group.

       IPV6_MULTICAST_HOPS

              Multicast hop limit.

       IPV6_MULTICAST_IF
              Interface to use for outgoing multicast packets.

       IPV6_MULTICAST_LOOP

              Multicast packets are delivered back to the local application.

       IPV6_UNICAST_HOPS
              Unicast hop limit.

       IPV6_V6ONLY
              Restrict AF_INET6 socket to IPv6 communications only.


       The  <netinet/in.h>  header shall define the following macros that test for special IPv6 addresses. Each macro is of type
       int and takes a single argument of type const struct in6_addr *:

       IN6_IS_ADDR_UNSPECIFIED

              Unspecified address.

       IN6_IS_ADDR_LOOPBACK

              Loopback address.

       IN6_IS_ADDR_MULTICAST

              Multicast address.

       IN6_IS_ADDR_LINKLOCAL

              Unicast link-local address.

       IN6_IS_ADDR_SITELOCAL

              Unicast site-local address.

       IN6_IS_ADDR_V4MAPPED

              IPv4 mapped address.

       IN6_IS_ADDR_V4COMPAT

              IPv4-compatible address.

       IN6_IS_ADDR_MC_NODELOCAL

              Multicast node-local address.

       IN6_IS_ADDR_MC_LINKLOCAL

              Multicast link-local address.

       IN6_IS_ADDR_MC_SITELOCAL

              Multicast site-local address.

       IN6_IS_ADDR_MC_ORGLOCAL

              Multicast organization-local address.

       IN6_IS_ADDR_MC_GLOBAL

              Multicast global address.


       The following sections are informative.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Host  and  Network  Byte  Orders,  <arpa/inet.h>,  <inttypes.h>,  <sys/socket.h>,  the  System   Interfaces   volume   of
       IEEE Std 1003.1-2001, connect(), getsockopt(), htonl(), htons(), ntohl(), ntohs(), sendmsg(), sendto(), setsockopt()

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open  Group
       Standard   is   the   referee   document.   The   original   Standard   can   be   obtained  online  at  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                            <netinet/in.h>(0P)