+++ /dev/null
-/* Copyright (c) 2013 Pavel Šimerda, Red Hat, Inc. (psimerda at redhat.com) and others
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
- * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-#include <netresolve-backend.h>
-#include <ares.h>
-#include <arpa/nameser.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-/* A timeout starting when the first successful answer has been received. */
-static int partial_timeout = 5;
-
-struct priv_dns {
- ares_channel query;
- fd_set rfds;
- fd_set wfds;
- int nfds;
- int ptfd;
- struct ares_srv_reply *srv_reply;
-};
-
-static void
-register_fds(netresolve_query_t query)
-{
- struct priv_dns *priv = netresolve_backend_get_priv(query);
- fd_set rfds;
- fd_set wfds;
- int nfds, fd;
-
- FD_ZERO(&rfds);
- FD_ZERO(&wfds);
- nfds = ares_fds(priv->query, &rfds, &wfds);
-
- for (fd = 0; fd < nfds || fd < priv->nfds; fd++) {
- if (!FD_ISSET(fd, &rfds) && FD_ISSET(fd, &priv->rfds)) {
- FD_CLR(fd, &priv->rfds);
- netresolve_backend_watch_fd(query, fd, 0);
- } else if (FD_ISSET(fd, &rfds) && !FD_ISSET(fd, &priv->rfds)) {
- FD_SET(fd, &priv->rfds);
- netresolve_backend_watch_fd(query, fd, POLLIN);
- }
- if (!FD_ISSET(fd, &wfds) && FD_ISSET(fd, &priv->wfds)) {
- FD_CLR(fd, &priv->wfds);
- netresolve_backend_watch_fd(query, fd, 0);
- } else if (FD_ISSET(fd, &wfds) && !FD_ISSET(fd, &priv->wfds)) {
- FD_SET(fd, &priv->wfds);
- netresolve_backend_watch_fd(query, fd, POLLOUT);
- }
- }
-
- priv->nfds = nfds;
-
- if (!nfds)
- netresolve_backend_finished(query);
-}
-
-struct priv_address_lookup {
- netresolve_query_t query;
- struct ares_srv_reply *srv;
-};
-
-static void
-host_callback(void *arg, int status, int timeouts, struct hostent *he)
-{
- struct priv_address_lookup *lookup_data = arg;
- netresolve_query_t query = lookup_data->query;
- struct ares_srv_reply *srv = lookup_data->srv;
- struct priv_dns *priv = netresolve_backend_get_priv(query);
- int socktype = -1;
- int protocol = -1;
- int port = -1;
- int priority = 0;
- int weight = 0;
-
- if (srv) {
- socktype = netresolve_backend_get_socktype(query);
- protocol = netresolve_backend_get_protocol(query);
- port = srv->port;
- priority = srv->priority;
- weight = srv->weight;
- }
-
- switch (status) {
- case ARES_EDESTRUCTION:
- break;
- case ARES_SUCCESS:
- priv->ptfd = netresolve_backend_add_timeout(query, partial_timeout, 0);
- if (priv->ptfd == -1)
- error("timer: %s", strerror(errno));
- netresolve_backend_apply_hostent(query, he, socktype, protocol, port, priority, weight);
- break;
- default:
- error("ares: %s\n", ares_strerror(status));
- }
-}
-
-static void
-start_address_lookup(netresolve_query_t query, struct ares_srv_reply *srv)
-{
- struct priv_dns *priv = netresolve_backend_get_priv(query);
- int family = netresolve_backend_get_family(query);
- const char *node = netresolve_backend_get_nodename(query);
- struct priv_address_lookup *lookup_data = calloc(1, sizeof *lookup_data);
-
- if (!lookup_data) {
- netresolve_backend_failed(query);
- return;
- }
-
- lookup_data->query = query;
-
- if (srv) {
- node = srv->host;
- lookup_data->srv = srv;
- }
-
- if (family == AF_INET || family == AF_UNSPEC)
- ares_gethostbyname(priv->query, node, AF_INET, host_callback, lookup_data);
- if (family == AF_INET6 || family == AF_UNSPEC)
- ares_gethostbyname(priv->query, node, AF_INET6, host_callback, lookup_data);
-}
-
-static void
-srv_callback(void *arg, int status, int timeouts, unsigned char *abuf, int alen)
-{
- netresolve_query_t query = arg;
- struct priv_dns *priv = netresolve_backend_get_priv(query);
-
- switch (status) {
- case ARES_EDESTRUCTION:
- break;
- case ARES_SUCCESS:
- status = ares_parse_srv_reply(abuf, alen, &priv->srv_reply);
- if (status)
- error("ares: SRV lookup failed: %s", ares_strerror(status));
- if (priv->srv_reply) {
- struct ares_srv_reply *reply;
-
- for (reply = priv->srv_reply; reply; reply = reply->next)
- start_address_lookup(query, reply);
- } else
- start_address_lookup(query, NULL);
- break;
- default:
- error("ares: %s\n", ares_strerror(status));
- }
-}
-
-static const char *
-protocol_to_string(int proto)
-{
- switch (proto) {
- case IPPROTO_UDP:
- return "udp";
- case IPPROTO_TCP:
- return "tcp";
- case IPPROTO_SCTP:
- return "sctp";
- default:
- return "0";
- }
-}
-
-static void
-start_srv_lookup(netresolve_query_t query)
-{
- struct priv_dns *priv = netresolve_backend_get_priv(query);
- char *name;
-
- if (asprintf(&name, "_%s._%s.%s",
- netresolve_backend_get_servname(query),
- protocol_to_string(netresolve_backend_get_protocol(query)),
- netresolve_backend_get_nodename(query)) == -1) {
- netresolve_backend_failed(query);
- return;
- }
-
- debug("looking up SRV %s\n", name);
- ares_query(priv->query, name, ns_c_in, ns_t_srv, srv_callback, query);
-}
-
-void
-start(netresolve_query_t query, char **settings)
-{
- struct priv_dns *priv = netresolve_backend_new_priv(query, sizeof *priv);
- /* ares doesn't seem to accept const options */
- static struct ares_options options = {
- .flags = ARES_FLAG_NOSEARCH | ARES_FLAG_NOALIASES,
- .lookups = "b"
- };
- int status;
-
- if (!priv)
- goto fail;
-
- priv->ptfd = -1;
-
- FD_ZERO(&priv->rfds);
- FD_ZERO(&priv->wfds);
-
- status = ares_library_init(ARES_LIB_INIT_ALL);
- if (status != ARES_SUCCESS)
- goto fail_ares;
- status = ares_init_options(&priv->query, &options,
- ARES_OPT_FLAGS | ARES_OPT_LOOKUPS);
- if (status != ARES_SUCCESS)
- goto fail_ares;
-
- if (netresolve_backend_get_dns_srv_lookup(query))
- start_srv_lookup(query);
- else
- start_address_lookup(query, NULL);
- register_fds(query);
-
- return;
-fail_ares:
- error("ares: %s\n", ares_strerror(status));
-fail:
- netresolve_backend_failed(query);
-}
-
-void
-dispatch(netresolve_query_t query, int fd, int events)
-{
- struct priv_dns *priv = netresolve_backend_get_priv(query);
-
- int rfd = events & POLLIN ? fd : ARES_SOCKET_BAD;
- int wfd = events & POLLOUT ? fd : ARES_SOCKET_BAD;
-
- if (fd == priv->ptfd) {
- error("partial response used due to a timeout\n");
- netresolve_backend_finished(query);
- return;
- }
-
- ares_process_fd(priv->query, rfd, wfd);
- register_fds(query);
-}
-
-void
-cleanup(netresolve_query_t query)
-{
- struct priv_dns *priv = netresolve_backend_get_priv(query);
- int fd;
-
- for (fd = 0; fd < priv->nfds; fd++) {
- if (FD_ISSET(fd, &priv->rfds) || FD_ISSET(fd, &priv->wfds)) {
- FD_CLR(fd, &priv->rfds);
- netresolve_backend_watch_fd(query, fd, 0);
- }
- }
-
- if (priv->ptfd != -1)
- netresolve_backend_remove_timeout(query, priv->ptfd);
- if (priv->srv_reply)
- ares_free_data(priv->srv_reply);
-
- ares_destroy(priv->query);
- //ares_library_cleanup();
-}
projects / netresolve.git / commitdiff