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/* $Id: dnsproc.c,v 1.9 2017/01/24 13:32:55 jsing Exp $ */ |
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/* |
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* Copyright (c) 2016 Kristaps Dzonsons <kristaps@bsd.lv> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/socket.h> |
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#include <arpa/inet.h> |
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#include <err.h> |
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#include <netdb.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include "extern.h" |
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struct addr { |
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int family; /* 4 for PF_INET, 6 for PF_INET6 */ |
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char ip[INET6_ADDRSTRLEN]; |
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}; |
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/* |
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* This is a modified version of host_dns in config.c of OpenBSD's ntpd. |
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*/ |
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/* |
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* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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static ssize_t |
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host_dns(const char *s, struct addr *vec) |
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{ |
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struct addrinfo hints, *res0, *res; |
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int error; |
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ssize_t vecsz; |
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struct sockaddr *sa; |
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memset(&hints, 0, sizeof(hints)); |
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hints.ai_family = PF_UNSPEC; |
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hints.ai_socktype = SOCK_DGRAM; /* DUMMY */ |
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/* ntpd MUST NOT use AI_ADDRCONFIG here */ |
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error = getaddrinfo(s, NULL, &hints, &res0); |
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if (error == EAI_AGAIN || |
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/* FIXME */ |
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#ifndef __FreeBSD__ |
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error == EAI_NODATA || |
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#endif |
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error == EAI_NONAME) |
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return 0; |
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if (error) { |
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warnx("%s: parse error: %s", |
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s, gai_strerror(error)); |
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return -1; |
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} |
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for (vecsz = 0, res = res0; |
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res != NULL && vecsz < MAX_SERVERS_DNS; |
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res = res->ai_next) { |
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if (res->ai_family != AF_INET && |
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res->ai_family != AF_INET6) |
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continue; |
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sa = res->ai_addr; |
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if (res->ai_family == AF_INET) { |
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vec[vecsz].family = 4; |
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inet_ntop(AF_INET, |
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&(((struct sockaddr_in *)sa)->sin_addr), |
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vec[vecsz].ip, INET6_ADDRSTRLEN); |
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} else { |
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vec[vecsz].family = 6; |
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inet_ntop(AF_INET6, |
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&(((struct sockaddr_in6 *)sa)->sin6_addr), |
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vec[vecsz].ip, INET6_ADDRSTRLEN); |
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} |
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dodbg("%s: DNS: %s", s, vec[vecsz].ip); |
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vecsz++; |
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break; |
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} |
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freeaddrinfo(res0); |
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return vecsz; |
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} |
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int |
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dnsproc(int nfd) |
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{ |
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char *look = NULL, *last = NULL; |
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struct addr v[MAX_SERVERS_DNS]; |
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int rc = 0, cc; |
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long lval; |
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ssize_t vsz = 0; |
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size_t i; |
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enum dnsop op; |
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if (pledge("stdio dns flock rpath cpath wpath", NULL) == -1) { |
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warn("pledge"); |
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goto out; |
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} |
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/* |
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* This is simple: just loop on a request operation, and each |
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* time we write back zero or more entries. |
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* Also do a simple trick and cache the last lookup. |
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*/ |
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for (;;) { |
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op = DNS__MAX; |
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if ((lval = readop(nfd, COMM_DNS)) == 0) |
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op = DNS_STOP; |
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else if (lval == DNS_LOOKUP) |
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op = lval; |
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if (op == DNS__MAX) { |
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warnx("unknown operation from netproc"); |
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goto out; |
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} else if (op == DNS_STOP) |
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break; |
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if ((look = readstr(nfd, COMM_DNSQ)) == NULL) |
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goto out; |
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/* |
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* Check if we're asked to repeat the lookup. |
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* If not, request it from host_dns(). |
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*/ |
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if (last == NULL || strcmp(look, last)) { |
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if ((vsz = host_dns(look, v)) < 0) |
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goto out; |
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free(last); |
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last = look; |
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look = NULL; |
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} else { |
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doddbg("%s: cached", look); |
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free(look); |
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look = NULL; |
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} |
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if ((cc = writeop(nfd, COMM_DNSLEN, vsz)) == 0) |
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break; |
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else if (cc < 0) |
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goto out; |
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for (i = 0; i < (size_t)vsz; i++) { |
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if (writeop(nfd, COMM_DNSF, v[i].family) <= 0) |
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goto out; |
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if (writestr(nfd, COMM_DNSA, v[i].ip) <= 0) |
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goto out; |
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} |
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} |
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rc = 1; |
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out: |
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close(nfd); |
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free(look); |
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free(last); |
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return rc; |
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} |