388 lines
13 KiB
Plaintext
388 lines
13 KiB
Plaintext
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
|
|
[<!ENTITY mdash "—">]>
|
|
<!--
|
|
- Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
|
|
- Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
|
|
-
|
|
- Permission to use, copy, modify, and/or distribute this software for any
|
|
- purpose with or without fee is hereby granted, provided that the above
|
|
- copyright notice and this permission notice appear in all copies.
|
|
-
|
|
- THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
|
|
- REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
- AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
|
|
- INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
|
|
- LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
|
|
- OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|
- PERFORMANCE OF THIS SOFTWARE.
|
|
-->
|
|
|
|
<!-- $Id: lwres_getaddrinfo.docbook,v 1.13 2007/06/18 23:47:51 tbox Exp $ -->
|
|
<refentry>
|
|
|
|
<refentryinfo>
|
|
<date>Jun 30, 2000</date>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>lwres_getaddrinfo</refentrytitle>
|
|
<manvolnum>3</manvolnum>
|
|
<refmiscinfo>BIND9</refmiscinfo>
|
|
</refmeta>
|
|
|
|
<docinfo>
|
|
<copyright>
|
|
<year>2004</year>
|
|
<year>2005</year>
|
|
<year>2007</year>
|
|
<holder>Internet Systems Consortium, Inc. ("ISC")</holder>
|
|
</copyright>
|
|
<copyright>
|
|
<year>2000</year>
|
|
<year>2001</year>
|
|
<year>2003</year>
|
|
<holder>Internet Software Consortium.</holder>
|
|
</copyright>
|
|
</docinfo>
|
|
|
|
<refnamediv>
|
|
<refname>lwres_getaddrinfo</refname>
|
|
<refname>lwres_freeaddrinfo</refname>
|
|
<refpurpose>socket address structure to host and service name</refpurpose>
|
|
</refnamediv>
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <lwres/netdb.h></funcsynopsisinfo>
|
|
<funcprototype>
|
|
<funcdef>
|
|
int
|
|
<function>lwres_getaddrinfo</function></funcdef>
|
|
<paramdef>const char *<parameter>hostname</parameter></paramdef>
|
|
<paramdef>const char *<parameter>servname</parameter></paramdef>
|
|
<paramdef>const struct addrinfo *<parameter>hints</parameter></paramdef>
|
|
<paramdef>struct addrinfo **<parameter>res</parameter></paramdef>
|
|
</funcprototype>
|
|
<funcprototype>
|
|
<funcdef>
|
|
void
|
|
<function>lwres_freeaddrinfo</function></funcdef>
|
|
<paramdef>struct addrinfo *<parameter>ai</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
|
|
<para>
|
|
If the operating system does not provide a
|
|
<type>struct addrinfo</type>,
|
|
the following structure is used:
|
|
</para>
|
|
<para><programlisting>
|
|
struct addrinfo {
|
|
int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
|
|
int ai_family; /* PF_xxx */
|
|
int ai_socktype; /* SOCK_xxx */
|
|
int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
|
|
size_t ai_addrlen; /* length of ai_addr */
|
|
char *ai_canonname; /* canonical name for hostname */
|
|
struct sockaddr *ai_addr; /* binary address */
|
|
struct addrinfo *ai_next; /* next structure in linked list */
|
|
};
|
|
</programlisting>
|
|
</para>
|
|
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>DESCRIPTION</title>
|
|
|
|
<para><function>lwres_getaddrinfo()</function>
|
|
is used to get a list of IP addresses and port numbers for host
|
|
<parameter>hostname</parameter> and service
|
|
<parameter>servname</parameter>.
|
|
|
|
The function is the lightweight resolver's implementation of
|
|
<function>getaddrinfo()</function> as defined in RFC2133.
|
|
<parameter>hostname</parameter> and
|
|
<parameter>servname</parameter> are pointers to null-terminated
|
|
strings or <type>NULL</type>.
|
|
|
|
<parameter>hostname</parameter> is either a host name or a
|
|
numeric host address string: a dotted decimal IPv4 address or an
|
|
IPv6 address. <parameter>servname</parameter> is either a
|
|
decimal port number or a service name as listed in
|
|
<filename>/etc/services</filename>.
|
|
</para>
|
|
|
|
<para><parameter>hints</parameter>
|
|
is an optional pointer to a
|
|
<type>struct addrinfo</type>.
|
|
This structure can be used to provide hints concerning the type of
|
|
socket
|
|
that the caller supports or wishes to use.
|
|
The caller can supply the following structure elements in
|
|
<parameter>*hints</parameter>:
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><constant>ai_family</constant></term>
|
|
<listitem>
|
|
<para>
|
|
The protocol family that should be used.
|
|
When
|
|
<constant>ai_family</constant>
|
|
is set to
|
|
<type>PF_UNSPEC</type>,
|
|
it means the caller will accept any protocol family supported by
|
|
the
|
|
operating system.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><constant>ai_socktype</constant></term>
|
|
<listitem>
|
|
<para>
|
|
denotes the type of socket —
|
|
<type>SOCK_STREAM</type>,
|
|
<type>SOCK_DGRAM</type>
|
|
or
|
|
<type>SOCK_RAW</type>
|
|
— that is wanted.
|
|
When
|
|
<constant>ai_socktype</constant>
|
|
is zero the caller will accept any socket type.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><constant>ai_protocol</constant></term>
|
|
<listitem>
|
|
<para>
|
|
indicates which transport protocol is wanted: IPPROTO_UDP or
|
|
IPPROTO_TCP.
|
|
If
|
|
<constant>ai_protocol</constant>
|
|
is zero the caller will accept any protocol.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><constant>ai_flags</constant></term>
|
|
<listitem>
|
|
<para>
|
|
Flag bits.
|
|
If the
|
|
<type>AI_CANONNAME</type>
|
|
bit is set, a successful call to
|
|
<function>lwres_getaddrinfo()</function>
|
|
will return a null-terminated string containing the canonical
|
|
name
|
|
of the specified hostname in
|
|
<constant>ai_canonname</constant>
|
|
of the first
|
|
<type>addrinfo</type>
|
|
structure returned.
|
|
Setting the
|
|
<type>AI_PASSIVE</type>
|
|
bit indicates that the returned socket address structure is
|
|
intended
|
|
for used in a call to
|
|
<citerefentry>
|
|
<refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>.
|
|
|
|
In this case, if the hostname argument is a
|
|
<type>NULL</type>
|
|
pointer, then the IP address portion of the socket
|
|
address structure will be set to
|
|
<type>INADDR_ANY</type>
|
|
for an IPv4 address or
|
|
<type>IN6ADDR_ANY_INIT</type>
|
|
for an IPv6 address.
|
|
</para>
|
|
<para>
|
|
When
|
|
<constant>ai_flags</constant>
|
|
does not set the
|
|
<type>AI_PASSIVE</type>
|
|
bit, the returned socket address structure will be ready
|
|
for use in a call to
|
|
<citerefentry>
|
|
<refentrytitle>connect</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>
|
|
for a connection-oriented protocol or
|
|
<citerefentry>
|
|
<refentrytitle>connect</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>sendto</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
or
|
|
<citerefentry>
|
|
<refentrytitle>sendmsg</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>
|
|
if a connectionless protocol was chosen.
|
|
The IP address portion of the socket address structure will be
|
|
set to the loopback address if
|
|
<parameter>hostname</parameter>
|
|
is a
|
|
<type>NULL</type>
|
|
pointer and
|
|
<type>AI_PASSIVE</type>
|
|
is not set in
|
|
<constant>ai_flags</constant>.
|
|
</para>
|
|
<para>
|
|
If
|
|
<constant>ai_flags</constant>
|
|
is set to
|
|
<type>AI_NUMERICHOST</type>
|
|
it indicates that
|
|
<parameter>hostname</parameter>
|
|
should be treated as a numeric string defining an IPv4 or IPv6
|
|
address
|
|
and no name resolution should be attempted.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
|
|
<para>
|
|
All other elements of the <type>struct addrinfo</type> passed
|
|
via <parameter>hints</parameter> must be zero.
|
|
</para>
|
|
|
|
<para>
|
|
A <parameter>hints</parameter> of <type>NULL</type> is
|
|
treated as if
|
|
the caller provided a <type>struct addrinfo</type> initialized to zero
|
|
with <constant>ai_family</constant>set to
|
|
<constant>PF_UNSPEC</constant>.
|
|
</para>
|
|
|
|
<para>
|
|
After a successful call to
|
|
<function>lwres_getaddrinfo()</function>,
|
|
<parameter>*res</parameter>
|
|
is a pointer to a linked list of one or more
|
|
<type>addrinfo</type>
|
|
structures.
|
|
Each
|
|
<type>struct addrinfo</type>
|
|
in this list cn be processed by following
|
|
the
|
|
<constant>ai_next</constant>
|
|
pointer, until a
|
|
<type>NULL</type>
|
|
pointer is encountered.
|
|
The three members
|
|
<constant>ai_family</constant>,
|
|
<constant>ai_socktype</constant>,
|
|
and
|
|
<constant>ai_protocol</constant>
|
|
in each
|
|
returned
|
|
<type>addrinfo</type>
|
|
structure contain the corresponding arguments for a call to
|
|
<citerefentry>
|
|
<refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>.
|
|
For each
|
|
<type>addrinfo</type>
|
|
structure in the list, the
|
|
<constant>ai_addr</constant>
|
|
member points to a filled-in socket address structure of length
|
|
<constant>ai_addrlen</constant>.
|
|
</para>
|
|
|
|
<para>
|
|
All of the information returned by
|
|
<function>lwres_getaddrinfo()</function>
|
|
is dynamically allocated: the addrinfo structures, and the socket
|
|
address structures and canonical host name strings pointed to by the
|
|
<constant>addrinfo</constant>structures.
|
|
Memory allocated for the dynamically allocated structures created by
|
|
a successful call to
|
|
<function>lwres_getaddrinfo()</function>
|
|
is released by
|
|
<function>lwres_freeaddrinfo()</function>.
|
|
<parameter>ai</parameter>
|
|
is a pointer to a
|
|
<type>struct addrinfo</type>
|
|
created by a call to
|
|
<function>lwres_getaddrinfo()</function>.
|
|
</para>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>RETURN VALUES</title>
|
|
|
|
<para><function>lwres_getaddrinfo()</function>
|
|
returns zero on success or one of the error codes listed in
|
|
<citerefentry>
|
|
<refentrytitle>gai_strerror</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>
|
|
if an error occurs. If both <parameter>hostname</parameter> and
|
|
<parameter>servname</parameter> are <type>NULL</type>
|
|
<function>lwres_getaddrinfo()</function> returns
|
|
<errorcode>EAI_NONAME</errorcode>.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1>
|
|
<title>SEE ALSO</title>
|
|
<para><citerefentry>
|
|
<refentrytitle>lwres</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>lwres_getaddrinfo</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>lwres_freeaddrinfo</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>lwres_gai_strerror</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>RFC2133</refentrytitle>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>getservbyname</refentrytitle><manvolnum>3</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>connect</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>sendto</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>sendmsg</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>,
|
|
|
|
<citerefentry>
|
|
<refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum>
|
|
</citerefentry>.
|
|
</para>
|
|
|
|
</refsect1>
|
|
</refentry><!--
|
|
- Local variables:
|
|
- mode: sgml
|
|
- End:
|
|
-->
|