from the ANSI standard

[unix-history] / usr / src / lib / libc / net / resolver.3

diff --git a/usr/src/lib/libc/net/resolver.3 b/usr/src/lib/libc/net/resolver.3
index 9c61e88..909e962 100644 (file)
--- a/usr/src/lib/libc/net/resolver.3
+++ b/usr/src/lib/libc/net/resolver.3
@@ -1,13 +1,24 @@
-.\" Copyright (c) 1985 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1985 The Regents of the University of California.
+.\" All rights reserved.

 .\"
 .\"

-.\"    @(#)resolver.3  1.5 (Berkeley) %G%
+.\" Redistribution and use in source and binary forms are permitted
+.\" provided that the above copyright notice and this paragraph are
+.\" duplicated in all such forms and that any documentation,
+.\" advertising materials, and other materials related to such
+.\" distribution and use acknowledge that the software was developed
+.\" by the University of California, Berkeley.  The name of the
+.\" University may not be used to endorse or promote products derived
+.\" from this software without specific prior written permission.
+.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 .\"
 .\"

-.TH RESOLVER 3 "15 November 1985"
+.\"    @(#)resolver.3  6.4 (Berkeley) %G%
+.\"
+.TH RESOLVER 3 ""

 .UC 4
 .SH NAME
 .UC 4
 .SH NAME

-res_mkquery, res_send, res_init, dn_comp, dn_expand \- resolver routines
+res_query, res_search, res_mkquery, res_send, res_init, dn_comp, dn_expand \- resolver routines

 .SH SYNOPSIS
 .B #include <sys/types.h>
 .br
 .SH SYNOPSIS
 .B #include <sys/types.h>
 .br


@@ -17,6 +28,26 @@ res_mkquery, res_send, res_init, dn_comp, dn_expand \- resolver routines
 .br
 .B #include <resolv.h>
 .PP
 .br
 .B #include <resolv.h>
 .PP

+.B "res_query(dname, class, type, answer, anslen)"
+.br
+.B char *dname;
+.br
+.B int class, type;
+.br
+.B u_char *answer;
+.br
+.B int anslen;
+.PP
+.B "res_search(dname, class, type, answer, anslen)"
+.br
+.B char *dname;
+.br
+.B int class, type;
+.br
+.B u_char *answer;
+.br
+.B int anslen;
+.PP

 .B "res_mkquery(op, dname, class, type, data, datalen, newrr, buf, buflen)"
 .br
 .B int op;
 .B "res_mkquery(op, dname, class, type, data, datalen, newrr, buf, buflen)"
 .br
 .B int op;


@@ -55,23 +86,27 @@ res_mkquery, res_send, res_init, dn_comp, dn_expand \- resolver routines
 .br
 .B char **dnptrs, **lastdnptr;
 .PP
 .br
 .B char **dnptrs, **lastdnptr;
 .PP

-.B dn_expand(msg, msglen, comp_dn, exp_dn, length)
+.B dn_expand(msg, eomorig, comp_dn, exp_dn, length)

 .br
 .br

-.B char *msg, *comp_dn, exp_dn;
+.B char *msg, *eomorig, *comp_dn, exp_dn;

 .br
 .br

-.B int  msglen, length;
+.B int  length;

 .SH DESCRIPTION
 .SH DESCRIPTION

-These routines are used for making, sending and interpreting packets to
-Internet domain name servers. Global information that is used by the
-resolver routines is kept in the variable
+These routines are used for making, sending and interpreting
+query and reply messages with Internet domain name servers.
+.PP
+Global configuration and state information that is used by the
+resolver routines is kept in the structure

 .IR _res .
 .IR _res .

-Most of the values have reasonable defaults and can be ignored. Options
+Most of the values have reasonable defaults and can be ignored.
+Options

 stored in
 .I _res.options
 are defined in
 .I resolv.h
 stored in
 .I _res.options
 are defined in
 .I resolv.h

-and are as follows. Options are a simple bit mask and are or'ed in to
-enable.
+and are as follows.
+Options are stored as a simple bit mask containing the bitwise ``or''
+of the options enabled.

 .IP RES_INIT
 True if the initial name server address and default domain name are
 initialized (i.e.,
 .IP RES_INIT
 True if the initial name server address and default domain name are
 initialized (i.e.,


@@ -81,11 +116,12 @@ has been called).
 Print debugging messages.
 .IP RES_AAONLY
 Accept authoritative answers only.
 Print debugging messages.
 .IP RES_AAONLY
 Accept authoritative answers only.

-.I Res_send
-will continue until it finds an authoritative answer or finds an error.
+With this option,
+.I res_send
+should continue until it finds an authoritative answer or finds an error.

 Currently this is not implemented.
 .IP RES_USEVC
 Currently this is not implemented.
 .IP RES_USEVC

-Use TCP connections for queries instead of UDP.
+Use TCP connections for queries instead of UDP datagrams.

 .IP RES_STAYOPEN
 Used with RES_USEVC to keep the TCP connection open between
 queries.
 .IP RES_STAYOPEN
 Used with RES_USEVC to keep the TCP connection open between
 queries.


@@ -94,88 +130,149 @@ UDP should be the normal mode used.
 .IP RES_IGNTC
 Unused currently (ignore truncation errors, i.e., don't retry with TCP).
 .IP RES_RECURSE
 .IP RES_IGNTC
 Unused currently (ignore truncation errors, i.e., don't retry with TCP).
 .IP RES_RECURSE

-Set the recursion desired bit in queries. This is the default.
-(
+Set the recursion-desired bit in queries.
+This is the default.
+(\c

 .I res_send
 does not do iterative queries and expects the name server
 to handle recursion.)
 .IP RES_DEFNAMES
 .I res_send
 does not do iterative queries and expects the name server
 to handle recursion.)
 .IP RES_DEFNAMES

-Append the default domain name to single label queries. This is the default.
+If set,
+.I res_search
+will append the default domain name to single-component names
+(those that do not contain a dot).
+This option is enabled by default.
+.IP RES_DNSRCH
+If this option is set,
+.I res_search
+will search for host names in the current domain and in parent domains; see
+.IR hostname (7).
+This is used by the standard host lookup routine
+.IR gethostbyname (3).
+This option is enabled by default.

 .PP
 .PP

-.I Res_init
-.PP
-reads the initialization file to get the default
-domain name and the Internet address of the initial hosts
-running the name server. If this line does not exist, the host running
+The
+.I res_init
+routine
+reads the configuration file (if any; see
+.IR resolver (5))
+to get the default domain name,
+search list and
+the Internet address of the local name server(s).
+If no server is configured, the host running

 the resolver is tried.
 the resolver is tried.

-.I Res_mkquery
-makes a standard query message and places it in
+The current domain name is defined by the hostname
+if not specified in the configuration file;
+it can be overridden by the environment variable LOCALDOMAIN.
+Initialization normally occurs on the first call
+to one of the following routines.
+.PP
+The
+.I res_query
+function provides an interface to the server query mechanism.
+It constructs a query, sends it to the local server,
+awaits a response, and makes preliminary checks on the reply.
+The query requests information of the specified
+.I type
+and
+.I class
+for the specified fully-qualified domain name
+.I dname .
+The reply message is left in the
+.I answer
+buffer with length
+.I anslen
+supplied by the caller.
+.PP
+The
+.I res_search
+routine makes a query and awaits a response like
+.IR res_query ,
+but in addition, it implements the default and search rules
+controlled by the RES_DEFNAMES and RES_DNSRCH options.
+It returns the first successful reply.
+.PP
+The remaining routines are lower-level routines used by
+.IR res_query .
+The
+.I res_mkquery
+function
+constructs a standard query message and places it in

 .IR buf .
 .IR buf .

-.I Res_mkquery
-will return the size of the query or \-1 if the query is
+It returns the size of the query, or \-1 if the query is

 larger than
 .IR buflen .
 larger than
 .IR buflen .

-.I Op
-is usually QUERY but can be any of the query types defined in
-.IR nameser.h .
-.I Dname
-is the domain name. If
-.I dname
-consists of a single label and the RES_DEFNAMES flag is enabled
-(the default),
-.I dname
-will be appended with the current domain name. The current
-domain name is defined in a system file and can be overridden
-by the environment variable LOCALDOMAIN.
+The query type
+.I op
+is usually QUERY, but can be any of the query types defined in
+.IR <arpa/nameser.h> .
+The domain name for the query is given by
+.IR dname .

 .I Newrr
 is currently unused but is intended for making update messages.
 .PP
 .I Newrr
 is currently unused but is intended for making update messages.
 .PP

-.I Res_send
-sends a query to name servers and returns an answer.
+The
+.I res_send
+routine
+sends a pre-formatted query and returns an answer.

 It will call
 .I res_init
 if RES_INIT is not set, send the query to the local name server, and
 It will call
 .I res_init
 if RES_INIT is not set, send the query to the local name server, and

-handle timeouts and retries. The length of the message is returned or
+handle timeouts and retries.
+The length of the reply message is returned, or

 \-1 if there were errors.
 .PP
 \-1 if there were errors.
 .PP

-.I Dn_expand
-Expands the compressed domain name
-.I comp_dn
-to a full domain name.  Expanded names are converted to upper case.
-.I Msg
-is a pointer to the beginning of the message,
-.I exp_dn
-is a pointer to a buffer of size
-.I length
-for the result.
-The size of compressed name is returned or -1 if there was an error.
-.PP
-.I Dn_comp
-Compresses the domain name
+The
+.I dn_comp
+function
+compresses the domain name

 .I exp_dn
 and stores it in
 .IR comp_dn .
 .I exp_dn
 and stores it in
 .IR comp_dn .

-The size of the compressed name is returned or -1 if there were errors.
-.I length is the size of the array pointed to by
-.IR comp_dn .
-.I Dnptrs
-is a list of pointers to previously compressed names in the current message.
+The size of the compressed name is returned or \-1 if there were errors.
+The size of the array pointed to by
+.I comp_dn
+is given by
+.IR length .
+The compression uses
+an array of pointers
+.I dnptrs
+to previously-compressed names in the current message.

 The first pointer points to
 to the beginning of the message and the list ends with NULL.
 The first pointer points to
 to the beginning of the message and the list ends with NULL.

-.I lastdnptr
-is a pointer to the end of the array pointed to
-.IR dnptrs .
-A side effect is to update the list of pointers for
-labels inserted into the message by
+The limit to the array is specified by
+.IR lastdnptr .
+A side effect of

 .I dn_comp
 .I dn_comp

+is to update the list of pointers for
+labels inserted into the message

 as the name is compressed.
 If
 .I dnptr
 as the name is compressed.
 If
 .I dnptr

-is NULL, we don't try to compress names. If
+is NULL, names are not compressed.
+If

 .I lastdnptr
 .I lastdnptr

-is NULL, we don't update the list.
+is NULL, the list of labels is not updated.
+.PP
+The
+.I dn_expand
+entry
+expands the compressed domain name
+.I comp_dn
+to a full domain name
+The compressed name is contained in a query or reply message;
+.I msg
+is a pointer to the beginning of the message.
+The uncompressed name is placed in the buffer indicated by
+.I exp_dn
+which is of size
+.IR length .
+The size of compressed name is returned or \-1 if there was an error.

 .SH FILES
 .SH FILES

-/etc/resolv.conf see resolver(5)
+/etc/resolv.conf       see resolver(5)

 .SH "SEE ALSO"
 .SH "SEE ALSO"

-named(8), resolver(5), RFC882, RFC883, RFC973, RFC974,
-BIND - Operations Guide
+gethostbyname(3), named(8), resolver(5), hostname(7),
+.br
+RFC1032, RFC1033, RFC1034, RFC1035, RFC974, 
+.br
+SMM:11 Name Server Operations Guide for BIND