Added new feature (rfc2671)
This commit is contained in:
parent
e447bc5c60
commit
90364defb0
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@ -20,6 +20,7 @@ CSOURCES = ares__close_sockets.c \
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ares_library_init.c \
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ares_llist.c \
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ares_mkquery.c \
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ares_create_query.c \
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ares_nowarn.c \
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ares_options.c \
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ares_parse_a_reply.c \
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@ -92,6 +93,7 @@ MANPAGES = ares_cancel.3 \
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ares_library_cleanup.3 \
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ares_library_init.3 \
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ares_mkquery.3 \
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ares_create_query.3 \
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ares_parse_a_reply.3 \
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ares_parse_aaaa_reply.3 \
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ares_parse_mx_reply.3 \
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@ -133,6 +135,7 @@ HTMLPAGES = ares_cancel.html \
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ares_library_cleanup.html \
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ares_library_init.html \
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ares_mkquery.html \
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ares_create_query.html \
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ares_parse_a_reply.html \
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ares_parse_aaaa_reply.html \
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ares_parse_mx_reply.html \
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@ -173,6 +176,7 @@ PDFPAGES = ares_cancel.pdf \
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ares_library_cleanup.pdf \
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ares_library_init.pdf \
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ares_mkquery.pdf \
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ares_create_query.pdf \
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ares_parse_a_reply.pdf \
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ares_parse_aaaa_reply.pdf \
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ares_parse_mx_reply.pdf \
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12
ares.h
12
ares.h
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@ -143,6 +143,7 @@ extern "C" {
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#define ARES_FLAG_NOSEARCH (1 << 5)
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#define ARES_FLAG_NOALIASES (1 << 6)
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#define ARES_FLAG_NOCHECKRESP (1 << 7)
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#define ARES_FLAG_EDNS (1 << 8)
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/* Option mask values */
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#define ARES_OPT_FLAGS (1 << 0)
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@ -160,6 +161,7 @@ extern "C" {
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#define ARES_OPT_SOCK_RCVBUF (1 << 12)
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#define ARES_OPT_TIMEOUTMS (1 << 13)
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#define ARES_OPT_ROTATE (1 << 14)
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#define ARES_OPT_EDNSPSZ (1 << 15)
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/* Nameinfo flag values */
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#define ARES_NI_NOFQDN (1 << 0)
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@ -265,6 +267,7 @@ struct ares_options {
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void *sock_state_cb_data;
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struct apattern *sortlist;
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int nsort;
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int ednspsz;
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};
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struct hostent;
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@ -403,6 +406,15 @@ CARES_EXTERN void ares_process_fd(ares_channel channel,
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ares_socket_t read_fd,
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ares_socket_t write_fd);
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CARES_EXTERN int ares_create_query(const char *name,
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int dnsclass,
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int type,
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unsigned short id,
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int rd,
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unsigned char **buf,
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int *buflen,
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int max_udp_size);
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CARES_EXTERN int ares_mkquery(const char *name,
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int dnsclass,
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int type,
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@ -0,0 +1,79 @@
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.\"
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.\" Copyright 1998, 2000 by the Massachusetts Institute of Technology.
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.\"
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.\" Permission to use, copy, modify, and distribute this
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.\" software and its documentation for any purpose and without
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.\" fee is hereby granted, provided that the above copyright
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.\" notice appear in all copies and that both that copyright
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.\" notice and this permission notice appear in supporting
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.\" documentation, and that the name of M.I.T. not be used in
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.\" advertising or publicity pertaining to distribution of the
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.\" software without specific, written prior permission.
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.\" M.I.T. makes no representations about the suitability of
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.\" this software for any purpose. It is provided "as is"
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.\" without express or implied warranty.
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.\"
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.TH ARES_CREATE_QUERY 3 "20 Nov 2009"
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.SH NAME
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ares_create_query \- Compose a single-question DNS query buffer
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.SH SYNOPSIS
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.nf
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.B #include <ares.h>
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.PP
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.B int ares_create_query(const char *\fIname\fP, int \fIdnsclass\fP,\
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int \fItype\fP,
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.B unsigned short \fIid\fP, int \fIrd\fP,\
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unsigned char **\fIbuf\fP,
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.B int *\fIbuflen\fP, int \fImax_udp_size\fP)
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.fi
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.SH DESCRIPTION
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The
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.B ares_create_query
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function composes a DNS query with a single question.
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The parameter
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.I name
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gives the query name as a NUL-terminated C string of period-separated
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labels optionally ending with a period; periods and backslashes within
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a label must be escaped with a backlash. The parameters
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.I dnsclass
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and
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.I type
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give the class and type of the query using the values defined in
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.BR <arpa/nameser.h> .
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The parameter
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.I id
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gives a 16-bit identifier for the query. The parameter
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.I rd
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should be nonzero if recursion is desired, zero if not. The query
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will be placed in an allocated buffer, a pointer to which will be
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stored in the variable pointed to by
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.IR buf ,
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and the length of which will be stored in the variable pointed to by
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.IR buflen .
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It is the caller's responsibility to free this buffer using
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\fIares_free_string(3)\fP when it is no longer needed.
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The parameter
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.I max_udp_size
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should be nonzero to activate EDNS. Usage of \fIares_create_query(3)\fP\ with
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.I max_udp_size
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set to zero is equivalent to \fIares_mkquery(3)\fP.
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.SH RETURN VALUES
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.B ares_create_query
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can return any of the following values:
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.TP 15
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.B ARES_SUCCESS
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Construction of the DNS query succeeded.
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.TP 15
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.B ARES_EBADNAME
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The query name
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.I name
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could not be encoded as a domain name, either because it contained a
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zero-length label or because it contained a label of more than 63
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characters.
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.TP 15
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.B ARES_ENOMEM
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Memory was exhausted.
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.SH SEE ALSO
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.BR ares_expand_name (3),
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.BR ares_free_string (3)
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.SH AUTHOR
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@ -0,0 +1,209 @@
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "ares_setup.h"
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#ifdef HAVE_SYS_SOCKET_H
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# include <sys/socket.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#ifdef HAVE_ARPA_NAMESER_H
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# include <arpa/nameser.h>
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#else
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# include "nameser.h"
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#endif
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#ifdef HAVE_ARPA_NAMESER_COMPAT_H
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# include <arpa/nameser_compat.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include "ares.h"
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#include "ares_dns.h"
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#include "ares_private.h"
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/* Header format, from RFC 1035:
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* 1 1 1 1 1 1
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | ID |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | QDCOUNT |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | ANCOUNT |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | NSCOUNT |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | ARCOUNT |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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*
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* AA, TC, RA, and RCODE are only set in responses. Brief description
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* of the remaining fields:
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* ID Identifier to match responses with queries
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* QR Query (0) or response (1)
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* Opcode For our purposes, always QUERY
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* RD Recursion desired
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* Z Reserved (zero)
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* QDCOUNT Number of queries
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* ANCOUNT Number of answers
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* NSCOUNT Number of name server records
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* ARCOUNT Number of additional records
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*
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* Question format, from RFC 1035:
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* 1 1 1 1 1 1
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | |
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* / QNAME /
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* / /
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | QTYPE |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | QCLASS |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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*
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* The query name is encoded as a series of labels, each represented
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* as a one-byte length (maximum 63) followed by the text of the
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* label. The list is terminated by a label of length zero (which can
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* be thought of as the root domain).
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*/
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int ares_create_query(const char *name, int dnsclass, int type,
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unsigned short id, int rd, unsigned char **buf,
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int *buflen, int max_udp_size)
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{
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int len;
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unsigned char *q;
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const char *p;
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/* Set our results early, in case we bail out early with an error. */
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*buflen = 0;
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*buf = NULL;
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/* Compute the length of the encoded name so we can check buflen.
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* Start counting at 1 for the zero-length label at the end. */
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len = 1;
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for (p = name; *p; p++)
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{
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if (*p == '\\' && *(p + 1) != 0)
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p++;
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len++;
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}
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/* If there are n periods in the name, there are n + 1 labels, and
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* thus n + 1 length fields, unless the name is empty or ends with a
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* period. So add 1 unless name is empty or ends with a period.
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*/
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if (*name && *(p - 1) != '.')
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len++;
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/* Immediately reject names that are longer than the maximum of 255
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* bytes that's specified in RFC 1035 ("To simplify implementations,
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* the total length of a domain name (i.e., label octets and label
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* length octets) is restricted to 255 octets or less."). We aren't
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* doing this just to be a stickler about RFCs. For names that are
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* too long, 'dnscache' closes its TCP connection to us immediately
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* (when using TCP) and ignores the request when using UDP, and
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* BIND's named returns ServFail (TCP or UDP). Sending a request
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* that we know will cause 'dnscache' to close the TCP connection is
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* painful, since that makes any other outstanding requests on that
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* connection fail. And sending a UDP request that we know
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* 'dnscache' will ignore is bad because resources will be tied up
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* until we time-out the request.
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*/
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if (len > MAXCDNAME)
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return ARES_EBADNAME;
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*buflen = len + HFIXEDSZ + QFIXEDSZ + (max_udp_size ? EDNSFIXEDSZ : 0);
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*buf = malloc(*buflen);
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if (!*buf)
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return ARES_ENOMEM;
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/* Set up the header. */
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q = *buf;
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memset(q, 0, HFIXEDSZ);
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DNS_HEADER_SET_QID(q, id);
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DNS_HEADER_SET_OPCODE(q, QUERY);
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if (rd) {
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DNS_HEADER_SET_RD(q, 1);
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}
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else {
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DNS_HEADER_SET_RD(q, 0);
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}
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DNS_HEADER_SET_QDCOUNT(q, 1);
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if (max_udp_size) {
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DNS_HEADER_SET_ARCOUNT(q, 1);
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}
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/* A name of "." is a screw case for the loop below, so adjust it. */
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if (strcmp(name, ".") == 0)
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name++;
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/* Start writing out the name after the header. */
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q += HFIXEDSZ;
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while (*name)
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{
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if (*name == '.')
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return ARES_EBADNAME;
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/* Count the number of bytes in this label. */
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len = 0;
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for (p = name; *p && *p != '.'; p++)
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{
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if (*p == '\\' && *(p + 1) != 0)
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p++;
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len++;
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}
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if (len > MAXLABEL)
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return ARES_EBADNAME;
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/* Encode the length and copy the data. */
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*q++ = (unsigned char)len;
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for (p = name; *p && *p != '.'; p++)
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{
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if (*p == '\\' && *(p + 1) != 0)
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p++;
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*q++ = *p;
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}
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/* Go to the next label and repeat, unless we hit the end. */
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if (!*p)
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break;
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name = p + 1;
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}
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/* Add the zero-length label at the end. */
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*q++ = 0;
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/* Finish off the question with the type and class. */
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DNS_QUESTION_SET_TYPE(q, type);
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DNS_QUESTION_SET_CLASS(q, dnsclass);
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if (max_udp_size)
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{
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q += QFIXEDSZ;
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memset(q, 0, EDNSFIXEDSZ);
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q++;
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DNS_RR_SET_TYPE(q, ns_t_opt);
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DNS_RR_SET_CLASS(q, max_udp_size);
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}
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return ARES_SUCCESS;
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}
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@ -95,9 +95,9 @@
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#define DNS_RR_LEN(r) DNS__16BIT((r) + 8)
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/* Macros for constructing the fixed part of a DNS resource record */
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#define DNS_RR_SET_TYPE(r) DNS__SET16BIT(r, v)
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#define DNS_RR_SET_CLASS(r) DNS__SET16BIT((r) + 2, v)
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#define DNS_RR_SET_TTL(r) DNS__SET32BIT((r) + 4, v)
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#define DNS_RR_SET_LEN(r) DNS__SET16BIT((r) + 8, v)
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#define DNS_RR_SET_TYPE(r, v) DNS__SET16BIT(r, v)
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#define DNS_RR_SET_CLASS(r, v) DNS__SET16BIT((r) + 2, v)
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#define DNS_RR_SET_TTL(r, v) DNS__SET32BIT((r) + 4, v)
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#define DNS_RR_SET_LEN(r, v) DNS__SET16BIT((r) + 8, v)
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#endif /* HEADER_CARES_DNS_H */
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@ -163,6 +163,7 @@ int ares_init_options(ares_channel *channelptr, struct ares_options *options,
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channel->rotate = -1;
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channel->udp_port = -1;
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channel->tcp_port = -1;
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channel->ednspsz = -1;
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channel->socket_send_buffer_size = -1;
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channel->socket_receive_buffer_size = -1;
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channel->nservers = -1;
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@ -453,6 +454,9 @@ static int init_by_options(ares_channel channel,
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&& channel->socket_receive_buffer_size == -1)
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channel->socket_receive_buffer_size = options->socket_receive_buffer_size;
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if ((optmask & ARES_OPT_EDNSPSZ) && channel->ednspsz == -1)
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channel->ednspsz = options->ednspsz;
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/* Copy the IPv4 servers, if given. */
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if ((optmask & ARES_OPT_SERVERS) && channel->nservers == -1)
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{
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@ -1358,6 +1362,9 @@ static int init_by_defaults(ares_channel channel)
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if (channel->tcp_port == -1)
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channel->tcp_port = htons(NAMESERVER_PORT);
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if (channel->ednspsz == -1)
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channel->ednspsz = EDNSPACKETSZ;
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if (channel->nservers == -1) {
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/* If nobody specified servers, try a local named. */
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channel->servers = malloc(sizeof(struct server_state));
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@ -25,6 +25,8 @@ ares_mkquery \- Compose a single-question DNS query buffer
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.B int *\fIbuflen\fP)
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.fi
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.SH DESCRIPTION
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Deprecated function. See \fIares_create_query(3)\fP instead!
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The
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.B ares_mkquery
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function composes a DNS query with a single question.
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@ -50,6 +52,11 @@ and the length of which will be stored in the variable pointed to by
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.IR buflen .
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It is the caller's responsibility to free this buffer using
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\fIares_free_string(3)\fP when it is no longer needed.
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Usage of \fIares_mkquery(3)\fP is deprecated, whereas the function is
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equivalent to \fIares_create_query(3)\fP with \fBmax_udp_size\fP set to
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0.
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.SH RETURN VALUES
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.B ares_mkquery
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can return any of the following values:
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173
ares_mkquery.c
173
ares_mkquery.c
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@ -15,181 +15,10 @@
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*/
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#include "ares_setup.h"
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#ifdef HAVE_SYS_SOCKET_H
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# include <sys/socket.h>
|
||||
#endif
|
||||
#ifdef HAVE_NETINET_IN_H
|
||||
# include <netinet/in.h>
|
||||
#endif
|
||||
#ifdef HAVE_ARPA_NAMESER_H
|
||||
# include <arpa/nameser.h>
|
||||
#else
|
||||
# include "nameser.h"
|
||||
#endif
|
||||
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
|
||||
# include <arpa/nameser_compat.h>
|
||||
#endif
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include "ares.h"
|
||||
#include "ares_dns.h"
|
||||
#include "ares_private.h"
|
||||
|
||||
/* Header format, from RFC 1035:
|
||||
* 1 1 1 1 1 1
|
||||
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | ID |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | QDCOUNT |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | ANCOUNT |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | NSCOUNT |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | ARCOUNT |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
*
|
||||
* AA, TC, RA, and RCODE are only set in responses. Brief description
|
||||
* of the remaining fields:
|
||||
* ID Identifier to match responses with queries
|
||||
* QR Query (0) or response (1)
|
||||
* Opcode For our purposes, always QUERY
|
||||
* RD Recursion desired
|
||||
* Z Reserved (zero)
|
||||
* QDCOUNT Number of queries
|
||||
* ANCOUNT Number of answers
|
||||
* NSCOUNT Number of name server records
|
||||
* ARCOUNT Number of additional records
|
||||
*
|
||||
* Question format, from RFC 1035:
|
||||
* 1 1 1 1 1 1
|
||||
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | |
|
||||
* / QNAME /
|
||||
* / /
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | QTYPE |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
* | QCLASS |
|
||||
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
*
|
||||
* The query name is encoded as a series of labels, each represented
|
||||
* as a one-byte length (maximum 63) followed by the text of the
|
||||
* label. The list is terminated by a label of length zero (which can
|
||||
* be thought of as the root domain).
|
||||
*/
|
||||
|
||||
int ares_mkquery(const char *name, int dnsclass, int type, unsigned short id,
|
||||
int rd, unsigned char **buf, int *buflen)
|
||||
{
|
||||
int len;
|
||||
unsigned char *q;
|
||||
const char *p;
|
||||
|
||||
/* Set our results early, in case we bail out early with an error. */
|
||||
*buflen = 0;
|
||||
*buf = NULL;
|
||||
|
||||
/* Compute the length of the encoded name so we can check buflen.
|
||||
* Start counting at 1 for the zero-length label at the end. */
|
||||
len = 1;
|
||||
for (p = name; *p; p++)
|
||||
{
|
||||
if (*p == '\\' && *(p + 1) != 0)
|
||||
p++;
|
||||
len++;
|
||||
}
|
||||
/* If there are n periods in the name, there are n + 1 labels, and
|
||||
* thus n + 1 length fields, unless the name is empty or ends with a
|
||||
* period. So add 1 unless name is empty or ends with a period.
|
||||
*/
|
||||
if (*name && *(p - 1) != '.')
|
||||
len++;
|
||||
|
||||
/* Immediately reject names that are longer than the maximum of 255
|
||||
* bytes that's specified in RFC 1035 ("To simplify implementations,
|
||||
* the total length of a domain name (i.e., label octets and label
|
||||
* length octets) is restricted to 255 octets or less."). We aren't
|
||||
* doing this just to be a stickler about RFCs. For names that are
|
||||
* too long, 'dnscache' closes its TCP connection to us immediately
|
||||
* (when using TCP) and ignores the request when using UDP, and
|
||||
* BIND's named returns ServFail (TCP or UDP). Sending a request
|
||||
* that we know will cause 'dnscache' to close the TCP connection is
|
||||
* painful, since that makes any other outstanding requests on that
|
||||
* connection fail. And sending a UDP request that we know
|
||||
* 'dnscache' will ignore is bad because resources will be tied up
|
||||
* until we time-out the request.
|
||||
*/
|
||||
if (len > MAXCDNAME)
|
||||
return ARES_EBADNAME;
|
||||
|
||||
*buflen = len + HFIXEDSZ + QFIXEDSZ;
|
||||
*buf = malloc(*buflen);
|
||||
if (!*buf)
|
||||
return ARES_ENOMEM;
|
||||
|
||||
/* Set up the header. */
|
||||
q = *buf;
|
||||
memset(q, 0, HFIXEDSZ);
|
||||
DNS_HEADER_SET_QID(q, id);
|
||||
DNS_HEADER_SET_OPCODE(q, QUERY);
|
||||
if (rd) {
|
||||
DNS_HEADER_SET_RD(q, 1);
|
||||
}
|
||||
else {
|
||||
DNS_HEADER_SET_RD(q, 0);
|
||||
}
|
||||
DNS_HEADER_SET_QDCOUNT(q, 1);
|
||||
|
||||
/* A name of "." is a screw case for the loop below, so adjust it. */
|
||||
if (strcmp(name, ".") == 0)
|
||||
name++;
|
||||
|
||||
/* Start writing out the name after the header. */
|
||||
q += HFIXEDSZ;
|
||||
while (*name)
|
||||
{
|
||||
if (*name == '.')
|
||||
return ARES_EBADNAME;
|
||||
|
||||
/* Count the number of bytes in this label. */
|
||||
len = 0;
|
||||
for (p = name; *p && *p != '.'; p++)
|
||||
{
|
||||
if (*p == '\\' && *(p + 1) != 0)
|
||||
p++;
|
||||
len++;
|
||||
}
|
||||
if (len > MAXLABEL)
|
||||
return ARES_EBADNAME;
|
||||
|
||||
/* Encode the length and copy the data. */
|
||||
*q++ = (unsigned char)len;
|
||||
for (p = name; *p && *p != '.'; p++)
|
||||
{
|
||||
if (*p == '\\' && *(p + 1) != 0)
|
||||
p++;
|
||||
*q++ = *p;
|
||||
}
|
||||
|
||||
/* Go to the next label and repeat, unless we hit the end. */
|
||||
if (!*p)
|
||||
break;
|
||||
name = p + 1;
|
||||
}
|
||||
|
||||
/* Add the zero-length label at the end. */
|
||||
*q++ = 0;
|
||||
|
||||
/* Finish off the question with the type and class. */
|
||||
DNS_QUESTION_SET_TYPE(q, type);
|
||||
DNS_QUESTION_SET_CLASS(q, dnsclass);
|
||||
|
||||
return ARES_SUCCESS;
|
||||
return ares_create_query(name, dnsclass, type, id, rd, buf, buflen, 0);
|
||||
}
|
||||
|
|
|
@ -113,6 +113,13 @@
|
|||
# define writev(s,ptr,cnt) ares_writev(s,ptr,cnt)
|
||||
#endif
|
||||
|
||||
/********* EDNS defines section ******/
|
||||
#define EDNSPACKETSZ 1280 /* Reasonable UDP payload size, as suggested
|
||||
in RFC2671 */
|
||||
#define MAXENDSSZ 4096 /* Maximum (local) limit for edns packet size */
|
||||
#define EDNSFIXEDSZ 11 /* Size of EDNS header */
|
||||
/********* EDNS defines section ******/
|
||||
|
||||
struct ares_addr {
|
||||
int family;
|
||||
union {
|
||||
|
@ -260,6 +267,7 @@ struct ares_channeldata {
|
|||
struct apattern *sortlist;
|
||||
int nsort;
|
||||
char *lookups;
|
||||
int ednspsz;
|
||||
|
||||
/* For binding to local devices and/or IP addresses. Leave
|
||||
* them null/zero for no binding.
|
||||
|
|
|
@ -430,7 +430,7 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
|
|||
struct server_state *server;
|
||||
int i;
|
||||
ssize_t count;
|
||||
unsigned char buf[PACKETSZ + 1];
|
||||
unsigned char buf[MAXENDSSZ + 1];
|
||||
#ifdef HAVE_RECVFROM
|
||||
ares_socklen_t fromlen;
|
||||
union {
|
||||
|
@ -541,7 +541,7 @@ static void process_answer(ares_channel channel, unsigned char *abuf,
|
|||
int alen, int whichserver, int tcp,
|
||||
struct timeval *now)
|
||||
{
|
||||
int tc, rcode;
|
||||
int tc, rcode, packetsz;
|
||||
unsigned short id;
|
||||
struct query *query;
|
||||
struct list_node* list_head;
|
||||
|
@ -578,11 +578,34 @@ static void process_answer(ares_channel channel, unsigned char *abuf,
|
|||
if (!query)
|
||||
return;
|
||||
|
||||
packetsz = PACKETSZ;
|
||||
/* If we use EDNS and server answers with one of these RCODES, the protocol
|
||||
* extension is not understood by the responder. We must retry the query
|
||||
* without EDNS enabled.
|
||||
*/
|
||||
if (channel->flags & ARES_FLAG_EDNS)
|
||||
{
|
||||
packetsz = channel->ednspsz;
|
||||
if (rcode == NOTIMP || rcode == FORMERR || rcode == SERVFAIL)
|
||||
{
|
||||
int qlen = alen - EDNSFIXEDSZ;
|
||||
channel->flags ^= ARES_FLAG_EDNS;
|
||||
query->tcplen -= EDNSFIXEDSZ;
|
||||
query->qlen -= EDNSFIXEDSZ;
|
||||
query->tcpbuf[0] = (unsigned char)((qlen >> 8) & 0xff);
|
||||
query->tcpbuf[1] = (unsigned char)(qlen & 0xff);
|
||||
DNS_HEADER_SET_ARCOUNT(query->tcpbuf + 2, 0);
|
||||
query->tcpbuf = realloc(query->tcpbuf, query->tcplen);
|
||||
ares__send_query(channel, query, now);
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
/* If we got a truncated UDP packet and are not ignoring truncation,
|
||||
* don't accept the packet, and switch the query to TCP if we hadn't
|
||||
* done so already.
|
||||
*/
|
||||
if ((tc || alen > PACKETSZ) && !tcp && !(channel->flags & ARES_FLAG_IGNTC))
|
||||
if ((tc || alen > packetsz) && !tcp && !(channel->flags & ARES_FLAG_IGNTC))
|
||||
{
|
||||
if (!query->using_tcp)
|
||||
{
|
||||
|
@ -595,8 +618,8 @@ static void process_answer(ares_channel channel, unsigned char *abuf,
|
|||
/* Limit alen to PACKETSZ if we aren't using TCP (only relevant if we
|
||||
* are ignoring truncation.
|
||||
*/
|
||||
if (alen > PACKETSZ && !tcp)
|
||||
alen = PACKETSZ;
|
||||
if (alen > packetsz && !tcp)
|
||||
alen = packetsz;
|
||||
|
||||
/* If we aren't passing through all error packets, discard packets
|
||||
* with SERVFAIL, NOTIMP, or REFUSED response codes.
|
||||
|
|
|
@ -114,8 +114,8 @@ void ares_query(ares_channel channel, const char *name, int dnsclass,
|
|||
|
||||
/* Compose the query. */
|
||||
rd = !(channel->flags & ARES_FLAG_NORECURSE);
|
||||
status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf,
|
||||
&qlen);
|
||||
status = ares_create_query(name, dnsclass, type, channel->next_id, rd, &qbuf,
|
||||
&qlen, (channel->flags & ARES_FLAG_EDNS) ? channel->ednspsz : 0);
|
||||
if (status != ARES_SUCCESS)
|
||||
{
|
||||
if (qbuf != NULL) free(qbuf);
|
||||
|
|
|
@ -42,7 +42,7 @@ void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
|
|||
ares_callback callback, void *arg)
|
||||
{
|
||||
struct query *query;
|
||||
int i;
|
||||
int i, packetsz;
|
||||
struct timeval now;
|
||||
|
||||
/* Verify that the query is at least long enough to hold the header. */
|
||||
|
@ -109,7 +109,10 @@ void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
|
|||
query->server_info[i].skip_server = 0;
|
||||
query->server_info[i].tcp_connection_generation = 0;
|
||||
}
|
||||
query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > PACKETSZ;
|
||||
|
||||
packetsz = (channel->flags & ARES_FLAG_EDNS) ? channel->ednspsz : PACKETSZ;
|
||||
query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > packetsz;
|
||||
|
||||
query->error_status = ARES_ECONNREFUSED;
|
||||
query->timeouts = 0;
|
||||
|
||||
|
|
Loading…
Reference in New Issue