1016 lines
29 KiB
C
1016 lines
29 KiB
C
/* minires.c. Stub synchronous resolver for Cygwin.
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Copyright 2006, 2008, 2009, 2010, 2011 Red Hat, Inc.
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Written by Pierre A. Humblet <Pierre.Humblet@ieee.org>
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include "minires.h"
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/***********************************************************************
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Utilities
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***********************************************************************/
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/***********************************************************************
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dprintf
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***********************************************************************/
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void minires_dprintf(const char * format, ...)
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{
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va_list args;
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va_start(args, format);
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fprintf(stderr, "Minires: ");
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vfprintf(stderr, format, args);
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va_end(args);
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}
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/***********************************************************************
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scanline
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Put pointers in list[] to the beginning of each space or comma delimited
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word in "in", and put the lengths in sizes[] (counting the final 0).
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Return the number of words found
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***********************************************************************/
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static int scanline(char * in, char **list, int * sizes, int maxnum)
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{
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int i;
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char * startp;
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for (i = 0; i < maxnum; i++) {
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while((*in) && (isspace((unsigned char)*in) || *in == ',')) in++;
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if (*in == 0)
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break;
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startp = in++;
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while((*in) && !isspace((unsigned char)*in) && *in != ',') in++;
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list[i] = startp;
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sizes[i] = in - startp + 1;
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if (*in)
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*in++ = 0;
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}
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return i;
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}
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/***********************************************************************
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Read the search string.
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***********************************************************************/
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void minires_get_search(char * string, res_state statp)
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{
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char * words[MAXDNSRCH+1], * ptr;
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int sizes[MAXDNSRCH+1];
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int i, j, debug = statp->options & RES_DEBUG;
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i = scanline(string, words, sizes, MAXDNSRCH+1);
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ptr = statp->defdname;
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for (j = 0; j < i; j++) {
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if (j < MAXDNSRCH
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&& ptr + sizes[j] < &statp->defdname[DIM(statp->defdname)]) {
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statp->dnsrch[j] = strcpy(ptr, words[j]);
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statp->dnsrch[j+1] = NULL;
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ptr += sizes[j];
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DPRINTF(debug, "search \"%s\"\n", words[j]);
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}
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else
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DPRINTF(debug, "no space for \"%s\"\n", words[j]);
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}
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}
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/***********************************************************************
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Read options
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***********************************************************************/
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static void get_options(res_state statp, int i, char **words)
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{
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char *ptr;
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int value;
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while (i-- > 0) {
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if (!strcasecmp("debug", words[i])) {
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statp->options |= RES_DEBUG;
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DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
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continue;
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}
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if (!strcasecmp("inet6", words[i])) {
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statp->options |= RES_USE_INET6;
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DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
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continue;
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}
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if (!strcasecmp("osquery", words[i])) {
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statp->use_os = 1;
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DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
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continue;
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}
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if ((ptr = strchr(words[i], ':'))) {
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*ptr++ = 0;
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value = atoi(ptr);
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/* Not supported
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if (!strcasecmp("ndots", words[i])) {
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statp->ndots = value;
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continue;
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}
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*/
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if (!strcasecmp("retry", words[i])
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|| !strcasecmp("attempts", words[i])) {
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if (value < 1)
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value = 1;
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else if (value > RES_MAXRETRY)
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value = RES_MAXRETRY;
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statp->retry = value;
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DPRINTF(statp->options & RES_DEBUG, "%s: %d\n", words[i], value);
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continue;
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}
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if (!strcasecmp("retrans", words[i])
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|| !strcasecmp("timeout", words[i])) {
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if (value < 1)
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value = 1;
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else if (value > RES_MAXRETRANS)
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value = RES_MAXRETRANS;
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statp->retrans = value;
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DPRINTF(statp->options & RES_DEBUG, "%s: %d\n", words[i], value);
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continue;
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}
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}
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DPRINTF(statp->options & RES_DEBUG, "unknown option: \"%s\"\n", words[i]);
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}
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}
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/***********************************************************************
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Read the resolv.conf file.
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We only look for nameserver, domain, search and options
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***********************************************************************/
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#if MAXNS > MAXDNSRCH + 1
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#define MAXSIZE MAXNS
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#else
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#define MAXSIZE MAXDNSRCH + 1 /* Make unused one visible */
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#endif
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static void get_resolv(res_state statp)
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{
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FILE * fd;
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char *words[MAXSIZE + 1], line[4096], *ptr;
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int sizes[DIM(words)];
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int i, j, ns = 0, have_search, have_address, debug = statp->options & RES_DEBUG;
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fd = fopen(_PATH_RESCONF, "r");
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DPRINTF(debug, _PATH_RESCONF ": %s\n", fd?"OK":strerror(errno));
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if (fd == NULL)
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return;
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statp->use_os = 0; /* Do not use os_query, except if allowed by "options" */
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have_search = (statp->dnsrch[0] != NULL);
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have_address = (statp->nscount != 0);
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while ( fgets(line, sizeof(line), fd) != 0) {
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DPRINTF(debug, "resolv.conf %s", line);
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if ((i = scanline(line, words, sizes, DIM(words))) > 0) {
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if (!have_address
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&& !strncasecmp("nameserver", words[0], sizes[0])) {
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for ( j = 1; j < i ; j++) {
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in_addr_t address;
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address = cygwin_inet_addr(words[j]);
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if (address == INADDR_NONE) {
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DPRINTF(debug, "invalid server \"%s\"\n", words[j]);
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}
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else if (ns >= MAXNS) {
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DPRINTF(debug, "no space for server \"%s\"\n", words[j]);
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}
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else {
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statp->nsaddr_list[ns++].sin_addr.s_addr = address;
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statp->nscount++;
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DPRINTF(debug, "server \"%s\"\n", words[j]);
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}
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}
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}
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else if (!have_search
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&& (!strncasecmp("search", words[0], sizes[0])
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|| !strncasecmp("domain", words[0], sizes[0]))) {
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ptr = statp->defdname;
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for (j = 0; j + 1 < i; j++) {
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if (j < MAXDNSRCH
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&& ptr + sizes[j + 1] < &statp->defdname[DIM(statp->defdname)]) {
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statp->dnsrch[j] = strcpy(ptr, words[j+1]);
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statp->dnsrch[j+1] = 0;
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ptr += sizes[j+1];
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DPRINTF(debug, "domain|search \"%s\"\n", statp->dnsrch[j]);
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}
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else {
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DPRINTF(debug, "no space for \"%s\"\n", words[j+1]);
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}
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}
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}
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/* Options line */
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else if (!strncasecmp("options", words[0], sizes[0]))
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get_options(statp, i - 1, &words[1]);
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}
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}
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fclose(fd);
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return;
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}
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/****************************************************************************/
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/*
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open_sock()
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Create a datagram socket and call bind.
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****************************************************************************/
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static int open_sock(struct sockaddr_in *CliAddr, int debug)
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{
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int fd;
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DPRINTF(debug, "opening UDP socket\n");
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/* Create a datagram socket */
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if ((fd = cygwin_socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
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DPRINTF(debug, "socket(UDP): %s\n", strerror(errno));
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return -1;
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}
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/* Set non-blocking */
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if (fcntl64(fd, F_SETFL, O_NONBLOCK) < 0) {
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DPRINTF(debug, "fcntl: %s\n", strerror(errno));
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return -1;
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}
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/* Set close on exec flag */
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if (fcntl64(fd, F_SETFD, 1) == -1) {
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DPRINTF(debug, "fcntl: %s\n", strerror(errno));
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return -1;
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}
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CliAddr->sin_family = AF_INET;
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CliAddr->sin_addr.s_addr = htonl(INADDR_ANY);
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CliAddr->sin_port = htons(0);
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bzero(CliAddr->sin_zero, sizeof(CliAddr->sin_zero));
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/* Get a port */
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if (cygwin_bind(fd, (struct sockaddr *) CliAddr, sizeof(*CliAddr)) < 0) {
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DPRINTF(debug, "bind: %s\n", strerror(errno));
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return -1;
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}
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return fd;
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}
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/*****************************************************************
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*
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__res_state()
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Undocumented but public. Accessed through _res
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*****************************************************************/
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static struct __res_state res;
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struct __res_state *__res_state(void)
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{
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return & res;
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}
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/*****************************************************************
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*
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res_init()
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*****************************************************************/
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int res_ninit(res_state statp)
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{
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int i;
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statp->res_h_errno = NETDB_SUCCESS;
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/* Only debug may be set before calling init */
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statp->options &= RES_DEBUG;
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statp->options |= RES_INIT | RES_DEFAULT;
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statp->nscount = 0;
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statp->os_query = NULL;
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statp->retrans = RES_TIMEOUT; /* timeout in seconds */
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statp->retry = RES_MAXRETRY; /* max number of retries */
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statp->use_os = 1; /* use os_query if available and allowed by get_resolv */
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statp->mypid = -1;
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statp->sockfd = -1;
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/* Use the pid and the ppid for random seed, from the point of view of an outsider.
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Mix the upper and lower bits as they are not used equally */
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i = getpid();
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statp->id = (ushort) (getppid() ^ (i << 8) ^ (i >> 8));
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for (i = 0; i < (int) DIM(statp->dnsrch); i++) statp->dnsrch[i] = 0;
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/* resolv.conf (dns servers & search list)*/
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get_resolv(statp);
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/* Get dns servers and search list from an os-specific routine, set os_query */
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get_dns_info(statp);
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if (statp->nscount == 0 && !statp->os_query) {
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errno = ENONET;
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statp->res_h_errno = NETDB_INTERNAL;
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DPRINTF(statp->options & RES_DEBUG, "no dns server found\n");
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return -1;
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}
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for (i = 0; i < statp->nscount; i++) {
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statp->nsaddr_list[i].sin_family = AF_INET;
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statp->nsaddr_list[i].sin_port = htons(NAMESERVER_PORT);
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bzero(statp->nsaddr_list[i].sin_zero, sizeof(statp->nsaddr_list[i].sin_zero));
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}
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return 0;
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}
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int res_init()
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{
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int r = res_ninit(& res);
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h_errno = res.res_h_errno;
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return r;
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}
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/*****************************************************************
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*
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res_close()
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*****************************************************************/
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void res_nclose(res_state statp)
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{
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int res;
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if (statp->sockfd != -1) {
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res = close(statp->sockfd);
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DPRINTF(statp->options & RES_DEBUG, "close sockfd %d: %s\n",
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statp->sockfd, (res == 0)?"OK":strerror(errno));
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statp->sockfd = -1;
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}
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}
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void res_close()
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{
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res_nclose(& res);
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}
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/*****************************************************************
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*
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get_tcp_buf()
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*****************************************************************/
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static int get_tcp_buf(int fd, unsigned char *buf, int size, int debug)
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{
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int res;
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while (size > 0) {
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if ((res = read(fd, buf, size)) < 0) {
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DPRINTF(debug, "read: %s\n", strerror(errno));
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return -1;
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}
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DPRINTF(debug, "read %d out of %d\n", res, size);
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size -= res;
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buf += res;
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}
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return 0;
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}
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/*****************************************************************
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*
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get_tcp()
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*****************************************************************/
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static int get_tcp(struct sockaddr_in *CliAddr,
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const unsigned char * MsgPtr, int MsgLength,
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unsigned char * AnsPtr, int AnsLength, int debug)
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{
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int fd, res = -1;
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unsigned short ans_length;
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union {short len; u_char buf[sizeof(short)];} len_buf;
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DPRINTF(debug, "retrying with TCP\n");
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/* Create a tcp socket */
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if ((fd = cygwin_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
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DPRINTF(debug, "socket(TCP): %s\n", strerror(errno));
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return -1;
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}
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if (cygwin_connect(fd, (struct sockaddr *) CliAddr, sizeof(* CliAddr)) < 0) {
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DPRINTF(debug, "connect: %s\n", strerror(errno));
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goto done;
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}
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/* Send the length then the message */
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len_buf.len = htons(MsgLength);
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if (write(fd, len_buf.buf, sizeof(len_buf)) != sizeof(len_buf)
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|| write(fd, MsgPtr, MsgLength) != MsgLength) {
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DPRINTF(debug, "write: %s\n", strerror(errno));
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goto done;
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}
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/* Read the answer length */
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if (get_tcp_buf(fd, len_buf.buf, sizeof(len_buf), debug))
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goto done;
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ans_length = ntohs(len_buf.len);
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/* Read the answer */
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if (get_tcp_buf(fd, AnsPtr, MIN(ans_length, AnsLength), debug))
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goto done;
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res = ans_length;
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done:
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close (fd);
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return res;
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}
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/*****************************************************************
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**
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res_send
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Assumes that the message is a query starting with a short id.
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Handles retransmissions until that id is received.
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*****************************************************************/
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int res_nsend( res_state statp, const unsigned char * MsgPtr,
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int MsgLength, unsigned char * AnsPtr, int AnsLength)
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{
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/* Current server, shared by all tasks */
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static volatile unsigned int SServ = 0XFFFFFFFF;
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int tcp;
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const int debug = statp->options & RES_DEBUG;
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fd_set fdset_read;
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int rslt, addrLen, transNum, wServ;
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struct sockaddr_in mySockAddr, dnsSockAddr;
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struct timeval timeOut;
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statp->res_h_errno = NETDB_SUCCESS;
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if (((statp->options & RES_INIT) == 0) && (res_ninit(statp) != 0))
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return -1;
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/* If a hook exists to a native implementation, use it */
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if (statp->os_query) {
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int len;
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short int Class, Type;
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char DomName[MAXDNAME];
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unsigned char * ptr = (unsigned char *) MsgPtr + HFIXEDSZ;
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len = dn_expand(MsgPtr, MsgPtr + MsgLength, ptr, DomName, sizeof(DomName));
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if (len > 0) {
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ptr += len;
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GETSHORT(Type, ptr);
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GETSHORT(Class, ptr);
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return ((os_query_t *) statp->os_query)(statp, DomName, Class, Type, AnsPtr, AnsLength);
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}
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else {
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/* dn_expand sets errno */
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statp->res_h_errno = NETDB_INTERNAL;
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return -1;
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}
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}
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/* Close the socket if it had been opened before a fork.
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Reuse of pid's cannot hurt */
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if ((statp->sockfd != -1) && ((pid_t) statp->mypid != getpid())) {
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res_nclose(statp);
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}
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/* Open a socket for this process */
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if (statp->sockfd == -1) {
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/* Create a non-blocking, close on exec socket and bind it (to any port) */
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statp->sockfd = open_sock(& mySockAddr, debug);
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if (statp->sockfd < 0 ) {
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statp->res_h_errno = NETDB_INTERNAL;
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return -1;
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}
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statp->mypid = getpid();
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if (SServ == 0XFFFFFFFF) /* Pseudo random */
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SServ = statp->id % statp->nscount;
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}
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transNum = 0;
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while ( transNum++ < statp->retry) {
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if ((wServ = SServ + 1) >= statp->nscount)
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wServ = 0;
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SServ = wServ;
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/* There exists attacks on DNS where many wrong answers with guessed id's and
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spoofed source address and port are generated at about the time when the
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program is tricked into resolving a name.
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This routine runs through the retry loop for each incorrect answer.
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It is thus extremely likely that such attacks will cause a TRY_AGAIN return,
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probably causing the calling program to retry after a delay.
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Note that valid late or duplicate answers to a previous questions also cause
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a retry, although this is minimized by flushing the socket before sending the
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new question.
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*/
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/* Flush duplicate or late answers */
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while ((rslt = cygwin_recvfrom( statp->sockfd, AnsPtr, AnsLength, 0, NULL, NULL)) >= 0) {
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DPRINTF(debug, "Flushed %d bytes\n", rslt);
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}
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DPRINTF(debug && (errno != EWOULDBLOCK),
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"Unexpected errno for flushing recvfrom: %s", strerror(errno));
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/* Send the message */
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rslt = cygwin_sendto(statp->sockfd, MsgPtr, MsgLength, 0,
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(struct sockaddr *) &statp->nsaddr_list[wServ],
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sizeof(struct sockaddr_in));
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DPRINTF(debug, "sendto: server %08x sockfd %d %s\n",
|
||
statp->nsaddr_list[wServ].sin_addr.s_addr,
|
||
statp->sockfd, (rslt == MsgLength)?"OK":strerror(errno));
|
||
if (rslt != MsgLength) {
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
};
|
||
/*
|
||
Wait for a reply with select()
|
||
*/
|
||
FD_ZERO(&fdset_read);
|
||
FD_SET (statp->sockfd, &fdset_read );
|
||
timeOut.tv_sec = statp->retrans;
|
||
timeOut.tv_usec = 0;
|
||
rslt = cygwin_select(statp->sockfd + 1, &fdset_read, NULL, NULL, &timeOut);
|
||
if ( rslt == 0 ) { /* Timeout */
|
||
DPRINTF(statp->options & RES_DEBUG, "timeout for server %08x\n",
|
||
statp->nsaddr_list[wServ].sin_addr.s_addr);
|
||
continue;
|
||
}
|
||
else if ((rslt != 1) || (FD_ISSET(statp->sockfd, &fdset_read) == 0)) {
|
||
DPRINTF(debug, "select: %s\n", strerror(errno));
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
}
|
||
|
||
addrLen = sizeof(dnsSockAddr);
|
||
rslt = cygwin_recvfrom(statp->sockfd, AnsPtr, AnsLength, 0,
|
||
(struct sockaddr *) & dnsSockAddr, & addrLen);
|
||
if (rslt <= 0) {
|
||
DPRINTF(debug, "recvfrom: %s\n", strerror(errno));
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
}
|
||
DPRINTF(debug, "recvfrom: %d bytes from %08x\n", rslt, dnsSockAddr.sin_addr.s_addr);
|
||
/*
|
||
Prepare to retry with tcp
|
||
*/
|
||
for (tcp = 0; tcp < 2; tcp++) {
|
||
/* Check if this is the expected message from the expected server */
|
||
if ((memcmp(& dnsSockAddr, & statp->nsaddr_list[wServ],
|
||
(char *) & dnsSockAddr.sin_zero[0] - (char *) & dnsSockAddr) == 0)
|
||
&& (rslt >= HFIXEDSZ)
|
||
&& (*MsgPtr == *AnsPtr) /* Ids match */
|
||
&& (*(MsgPtr + 1) == *(AnsPtr + 1))
|
||
&& ((AnsPtr[2] & QR) != 0)
|
||
&& (AnsPtr[4] == 0)
|
||
/* We check the question if present.
|
||
Some servers don't return it on error, in particular
|
||
when the name in the question is not valid. */
|
||
&& (((AnsPtr[5] == 0)
|
||
&& ((AnsPtr[3] & ERR_MASK) != NOERROR))
|
||
|| ((AnsPtr[5] == 1)
|
||
&& (rslt >= MsgLength)
|
||
&& (memcmp(MsgPtr + HFIXEDSZ, AnsPtr + HFIXEDSZ, MsgLength - HFIXEDSZ) == 0)))) {
|
||
if ((AnsPtr[3] & ERR_MASK) == NOERROR) {
|
||
if ((AnsPtr[2] & TC) && (tcp == 0) && !(statp->options & RES_IGNTC)) {
|
||
/* Truncated. Try TCP */
|
||
rslt = get_tcp(&statp->nsaddr_list[wServ], MsgPtr, MsgLength,
|
||
AnsPtr, AnsLength, statp->options & RES_DEBUG);
|
||
continue /* Tcp loop */;
|
||
}
|
||
else if ((AnsPtr[6] | AnsPtr[7])!= 0)
|
||
return rslt;
|
||
else
|
||
statp->res_h_errno = NO_DATA;
|
||
}
|
||
#if 0
|
||
NETDB_INTERNAL -1 /* see errno */
|
||
NETDB_SUCCESS 0 /* no problem */
|
||
HOST_NOT_FOUND 1 /* Authoritative Answer Host not found */
|
||
TRY_AGAIN 2 /* Non-Authoritive Host not found, or SERVERFAIL */
|
||
Also seen returned by some servers when the name is too long
|
||
NO_RECOVERY 3 /* Non recoverable errors, FORMERR, REFUSED, NOTIMP */
|
||
NO_DATA 4 /* Valid name, no data record of requested type */
|
||
#endif
|
||
else {
|
||
switch (AnsPtr[3] & ERR_MASK) {
|
||
/* return HOST_NOT_FOUND even for non-authoritative answers */
|
||
case NXDOMAIN:
|
||
case FORMERR:
|
||
statp->res_h_errno = HOST_NOT_FOUND;
|
||
break;
|
||
case SERVFAIL:
|
||
statp->res_h_errno = TRY_AGAIN;
|
||
break;
|
||
default:
|
||
statp->res_h_errno = NO_RECOVERY;
|
||
}
|
||
}
|
||
return -1;
|
||
}
|
||
else {
|
||
DPRINTF(debug, "unexpected answer\n");
|
||
break;
|
||
}
|
||
} /* TCP */
|
||
}
|
||
DPRINTF(debug, "too many retries\n");
|
||
statp->res_h_errno = TRY_AGAIN;
|
||
return -1;
|
||
}
|
||
|
||
int res_send( const unsigned char * MsgPtr, int MsgLength,
|
||
unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
int r = res_nsend(& res, MsgPtr, MsgLength, AnsPtr, AnsLength);
|
||
h_errno = res.res_h_errno;
|
||
return r;
|
||
}
|
||
|
||
/*****************************************************************
|
||
*
|
||
res_mkquery
|
||
|
||
Return: packet size
|
||
-1 name format is incorrect
|
||
*****************************************************************/
|
||
int res_nmkquery (res_state statp,
|
||
int op, const char * dnameptr, int qclass, int qtype,
|
||
const unsigned char * dataptr __attribute__ ((unused)),
|
||
int datalen __attribute__ ((unused)),
|
||
const unsigned char * newrr __attribute__ ((unused)),
|
||
unsigned char * buf, int buflen)
|
||
{
|
||
int i, len;
|
||
const char * ptr;
|
||
unsigned int id4;
|
||
|
||
if (op == QUERY) {
|
||
/* Write the name and verify buffer length */
|
||
len = dn_comp(dnameptr, buf + HFIXEDSZ, buflen - HFIXEDSZ - QFIXEDSZ, NULL, NULL);
|
||
if (len < 0) {
|
||
DPRINTF(statp->options & RES_DEBUG,
|
||
"\"%s\" invalid or buffer too short\n", dnameptr);
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
}
|
||
|
||
/* Fill the header */
|
||
PUTSHORT(statp->id, buf);
|
||
PUTSHORT(RD, buf);
|
||
PUTSHORT(1, buf); /* Number of questions */
|
||
for (i = 0; i < 3; i++)
|
||
PUTSHORT(0, buf); /* Number of answers */
|
||
|
||
/* Write qtype and qclass */
|
||
buf += len;
|
||
PUTSHORT(qtype, buf);
|
||
PUTSHORT(qclass, buf);
|
||
|
||
/* Update id. The current query adds entropy to the next query id */
|
||
for (id4 = qtype, i = 0, ptr = dnameptr; *ptr; ptr++, i += 3)
|
||
id4 ^= *ptr << (i & 0xF);
|
||
i = 1 + statp->id % 15; /* Between 1 and 16 */
|
||
/* id dependent rotation, also brings MSW to LSW */
|
||
id4 = (id4 << i) ^ (id4 >> (16 - i)) ^ (id4 >> (32 - i));
|
||
if ((short) id4)
|
||
statp->id ^= (short) id4;
|
||
else
|
||
statp->id++; /* Force change */
|
||
|
||
return len + (HFIXEDSZ + QFIXEDSZ); /* packet size */
|
||
}
|
||
else { /* Not implemented */
|
||
errno = ENOSYS;
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
}
|
||
}
|
||
|
||
int res_mkquery (int op, const char * dnameptr, int qclass, int qtype,
|
||
const unsigned char * dataptr, int datalen,
|
||
const unsigned char * newrr, unsigned char * buf, int buflen)
|
||
{
|
||
int r = res_nmkquery (& res, op, dnameptr, qclass, qtype,
|
||
dataptr, datalen, newrr, buf, buflen);
|
||
h_errno = res.res_h_errno;
|
||
return r;
|
||
|
||
}
|
||
|
||
/*****************************************************************
|
||
* res_query()
|
||
*****************************************************************/
|
||
|
||
int res_nquery( res_state statp, const char * DomName, int Class, int Type,
|
||
unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
u_char packet[PACKETSZ];
|
||
int len;
|
||
|
||
DPRINTF(statp->options & RES_DEBUG, "query \"%s\" type %d\n", DomName, Type);
|
||
statp->res_h_errno = NETDB_SUCCESS;
|
||
|
||
/* If a hook exists to a native implementation, use it */
|
||
if (statp->os_query)
|
||
return ((os_query_t *) statp->os_query)(statp, DomName, Class, Type, AnsPtr, AnsLength);
|
||
|
||
if ((len = res_nmkquery (statp, QUERY, DomName, Class, Type,
|
||
0, 0, 0, packet, PACKETSZ)) < 0)
|
||
return -1;
|
||
return res_nsend( statp, packet, len, AnsPtr, AnsLength);
|
||
}
|
||
|
||
int res_query( const char * DomName, int Class, int Type, unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
int r = res_nquery(& res, DomName, Class, Type, AnsPtr, AnsLength);
|
||
h_errno = res.res_h_errno;
|
||
return r;
|
||
}
|
||
|
||
/*****************************************************************
|
||
* res_querydomain()
|
||
*****************************************************************/
|
||
int res_nquerydomain( res_state statp, const char * Name, const char * DomName,
|
||
int Class, int Type, unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
char fqdn[MAXDNAME], *ptr;
|
||
size_t nlen;
|
||
|
||
if (!DomName)
|
||
ptr = (char *) Name;
|
||
else if ((nlen = strlen(Name)) >= sizeof(fqdn) - 1)
|
||
goto error;
|
||
else {
|
||
strcpy(fqdn, Name);
|
||
ptr = &fqdn[nlen];
|
||
if (nlen && *(ptr - 1) != '.')
|
||
*(ptr++ - 1) = '.';
|
||
fqdn[sizeof(fqdn) - 1] = 0;
|
||
strncpy(ptr, DomName, sizeof(fqdn) - (ptr - fqdn));
|
||
if (fqdn[sizeof(fqdn) - 1])
|
||
goto error;
|
||
ptr = fqdn;
|
||
}
|
||
return res_nquery(statp, ptr, Class, Type, AnsPtr, AnsLength);
|
||
|
||
error:
|
||
DPRINTF(statp->options & RES_DEBUG, "querydomain: name too long\n");
|
||
errno = EINVAL;
|
||
statp->res_h_errno = NETDB_INTERNAL;;
|
||
return -1;
|
||
}
|
||
|
||
int res_querydomain( const char * Name, const char * DomName, int Class,
|
||
int Type, unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
int r = res_nquerydomain(& res, Name, DomName, Class, Type, AnsPtr,
|
||
AnsLength);
|
||
h_errno = res.res_h_errno;
|
||
return r;
|
||
}
|
||
|
||
/*****************************************************************
|
||
*
|
||
res_search()
|
||
|
||
*****************************************************************/
|
||
|
||
int res_nsearch( res_state statp, const char * DomName, int Class, int Type,
|
||
unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
int len, stat, i;
|
||
char fullDomName[MAXDNAME], *ptr, *sptr;
|
||
|
||
DPRINTF(statp->options & RES_DEBUG, "search \"%s\" type %d\n", DomName, Type);
|
||
|
||
if (((statp->options & RES_INIT) == 0) && (res_ninit(statp) != 0))
|
||
return -1;
|
||
|
||
stat = res_nquery( statp, DomName, Class, Type, AnsPtr, AnsLength);
|
||
|
||
/* Check if will skip search */
|
||
if (statp->res_h_errno != HOST_NOT_FOUND /* Success or hard failure */
|
||
|| ((ptr = strrchr(DomName, '.')) && (!*(ptr+1))) /* Final dot */
|
||
|| (((statp->options & RES_DNSRCH) == 0) /* Or no search */
|
||
&& ((ptr != NULL) /* And some dot */
|
||
|| ((statp->options & RES_DEFNAMES) == 0)))/* or no def domain */
|
||
|| (!(sptr = statp->dnsrch[0])))
|
||
return stat;
|
||
|
||
len = strlen(DomName);
|
||
if (len >= MAXDNAME - 1) /* Space for next dot */
|
||
goto error;
|
||
strcpy(fullDomName, DomName);
|
||
fullDomName[len++] = '.';
|
||
fullDomName[MAXDNAME - 1] = 0; /* Overflow indicator */
|
||
i = 0;
|
||
do {
|
||
strncpy(fullDomName + len, sptr, MAXDNAME - len);
|
||
if (fullDomName[MAXDNAME - 1])
|
||
goto error;
|
||
stat = res_nquery(statp, fullDomName, Class, Type, AnsPtr, AnsLength);
|
||
} while ((sptr = statp->dnsrch[++i]) != NULL
|
||
&& statp->res_h_errno == HOST_NOT_FOUND
|
||
&& (statp->options & RES_DNSRCH) != 0);
|
||
|
||
/* Return last stat */
|
||
return stat;
|
||
|
||
error:
|
||
DPRINTF(statp->options & RES_DEBUG, "name too long during search\n");
|
||
errno = EINVAL;
|
||
statp->res_h_errno = NETDB_INTERNAL;
|
||
return -1;
|
||
}
|
||
|
||
int res_search( const char * DomName, int Class, int Type,
|
||
unsigned char * AnsPtr, int AnsLength)
|
||
{
|
||
int r = res_nsearch(& res, DomName, Class, Type, AnsPtr, AnsLength);
|
||
h_errno = res.res_h_errno;
|
||
return r;
|
||
}
|
||
|
||
/*****************************************************************
|
||
* dn_expand
|
||
*****************************************************************/
|
||
|
||
int dn_expand(const unsigned char *msg, const unsigned char *eomorig,
|
||
const unsigned char *comp_dn, char *exp_dn, int length)
|
||
{
|
||
unsigned int len, complen = 0;
|
||
const unsigned char *comp_dn_orig = comp_dn;
|
||
|
||
if (comp_dn >= eomorig)
|
||
goto expand_fail;
|
||
if ((len = *comp_dn++) == 0) /* Weird case */
|
||
exp_dn++;
|
||
else do {
|
||
if (len <= MAXLABEL) {
|
||
if ((length -= (len + 1)) >= 0 /* Need space for final . */
|
||
&& comp_dn + len <= eomorig) {
|
||
do { *exp_dn++ = *comp_dn++; } while (--len != 0);
|
||
*exp_dn++ = '.';
|
||
}
|
||
else
|
||
goto expand_fail;
|
||
}
|
||
else if (len >= (128+64)) {
|
||
if (!complen) /* Still in the original field? */
|
||
complen = (comp_dn - comp_dn_orig) + 1;
|
||
comp_dn = msg + (((len & ~(128+64)) << 8) + *comp_dn);
|
||
if (comp_dn >= eomorig)
|
||
goto expand_fail;
|
||
}
|
||
else
|
||
goto expand_fail;
|
||
} while ((len = *comp_dn++) != 0);
|
||
/* Replace last . with a 0 */
|
||
*(--exp_dn) = 0;
|
||
if (!complen)
|
||
complen = comp_dn - comp_dn_orig;
|
||
/* fprintf(stderr, "dn_expand %s\n", exp_start); */
|
||
return complen;
|
||
|
||
expand_fail:
|
||
errno = EINVAL;
|
||
return -1;
|
||
}
|
||
|
||
/*****************************************************************
|
||
*
|
||
dn_comp
|
||
|
||
Return -1 in case of overflow, but still fill buffer correctly.
|
||
We do not check the alphabet of the host names
|
||
nor the length of the compressed name and we
|
||
preserve the letter cases.
|
||
|
||
*****************************************************************/
|
||
int dn_comp(const char * exp_dn, u_char * comp_dn, int length,
|
||
u_char ** dnptrs, u_char ** lastdnptr)
|
||
{
|
||
u_char *cptr = comp_dn, *dptr, *lptr, *rptr;
|
||
unsigned int i, len;
|
||
u_char * const eptr = comp_dn + length - 1; /* Last valid */
|
||
|
||
errno = EINVAL;
|
||
|
||
if (*exp_dn == '.' && !*(exp_dn + 1))
|
||
exp_dn++;
|
||
while (1) {
|
||
if (*exp_dn == '.' || cptr > eptr)
|
||
return -1;
|
||
if (*exp_dn == 0) {
|
||
*cptr++ = 0;
|
||
break;
|
||
}
|
||
/* Try to compress */
|
||
if (dnptrs) {
|
||
for (i = 1; dnptrs[i]; i++) {
|
||
dptr = dnptrs[i];
|
||
if (dptr >= comp_dn) /* Handle name.name */
|
||
continue;
|
||
rptr = (u_char *) exp_dn;
|
||
len = *dptr++;
|
||
while (1) {
|
||
do {
|
||
if (*dptr++ != *rptr++)
|
||
goto next_dn;
|
||
} while (--len);
|
||
len = *dptr++;
|
||
if (len == 0) { /* last label */
|
||
if (!*rptr || (*rptr == '.' && !*(rptr + 1))) { /* Full match */
|
||
len = (dnptrs[i] - dnptrs[0]) | 0xC000;
|
||
/* Write pointer */
|
||
*cptr++ = len >> 8;
|
||
if (cptr > eptr)
|
||
return -1;
|
||
*cptr++ = len;
|
||
goto done;
|
||
}
|
||
goto next_dn;
|
||
}
|
||
if (*rptr++ != '.')
|
||
goto next_dn;
|
||
if (len >= 128 + 64) {
|
||
dptr = dnptrs[0] + ((len - 128 - 64) << 8) + *dptr;
|
||
len = *dptr++;
|
||
}
|
||
}
|
||
next_dn: ;
|
||
}
|
||
/* Record label if asked and if space is available and if not too far off */
|
||
if (lastdnptr && (lastdnptr != &dnptrs[i]) && (cptr - dnptrs[0]) < 0xC000) {
|
||
dnptrs[i] = cptr;
|
||
dnptrs[i+1] = NULL;
|
||
}
|
||
}
|
||
/* Write label */
|
||
lptr = cptr++; /* Length byte */
|
||
rptr = (u_char *) exp_dn;
|
||
do {
|
||
if (cptr <= eptr)
|
||
*cptr++ = *rptr;
|
||
} while ((*++rptr != '.') && (*rptr != 0));
|
||
len = rptr - (u_char *) exp_dn;
|
||
if (len > MAXLABEL)
|
||
return -1;
|
||
*lptr = len;
|
||
exp_dn = (char *) rptr;
|
||
if (*exp_dn != 0)
|
||
exp_dn++; /* Skip over . */
|
||
}
|
||
done:
|
||
return cptr - comp_dn;
|
||
}
|
||
|
||
/*****************************************************************
|
||
* dn_skipname
|
||
|
||
Measures the compressed domain name length and returns it.
|
||
*****************************************************************/
|
||
int dn_skipname(const unsigned char *comp_dn, const unsigned char *eom)
|
||
{
|
||
int len;
|
||
const unsigned char *comp_dn_orig = comp_dn;
|
||
|
||
do {
|
||
len = *comp_dn++;
|
||
if (len >= (128 + 64)) {
|
||
comp_dn++;
|
||
break;
|
||
}
|
||
if (len > MAXLABEL ||
|
||
(comp_dn += len) > eom)
|
||
return -1;
|
||
} while (len != 0);
|
||
|
||
return comp_dn - comp_dn_orig;
|
||
}
|
||
|
||
/*****************************************************************
|
||
* dn_length1 For internal use
|
||
|
||
Return length of uncompressed name incl final 0.
|
||
*****************************************************************/
|
||
|
||
int dn_length1(const unsigned char *msg, const unsigned char *eomorig,
|
||
const unsigned char *comp_dn)
|
||
{
|
||
unsigned int len, length = 0;
|
||
|
||
errno = EINVAL;
|
||
if (comp_dn >= eomorig)
|
||
goto expand_fail;
|
||
else while ((len = *comp_dn++) != 0) {
|
||
if (len <= MAXLABEL) {
|
||
if ((comp_dn += len) <= eomorig)
|
||
length += len + 1;
|
||
else
|
||
goto expand_fail;
|
||
}
|
||
else if (len >= (128+64)) {
|
||
comp_dn = msg + (((len & ~(128+64)) << 8) + *comp_dn);
|
||
if (comp_dn >= eomorig)
|
||
goto expand_fail;
|
||
}
|
||
else
|
||
goto expand_fail;
|
||
}
|
||
return length;
|
||
|
||
expand_fail:
|
||
return -1;
|
||
}
|