176 lines
4.5 KiB
C
176 lines
4.5 KiB
C
/* C-ARES DNS resolver integration */
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/*
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* (C) 2015 by Holger Hans Peter Freyther
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <openbsc/sgsn.h>
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#include <openbsc/debug.h>
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#include <netdb.h>
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struct cares_event_fd {
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struct llist_head head;
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struct osmo_fd fd;
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};
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struct cares_cb_data {
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ares_host_callback cb;
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void *data;
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};
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static void osmo_ares_reschedule(struct sgsn_instance *sgsn);
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static void ares_cb(void *_arg, int status, int timeouts, struct hostent *hostent)
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{
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struct cares_cb_data *arg = _arg;
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arg->cb(arg->data, status, timeouts, hostent);
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osmo_ares_reschedule(sgsn);
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talloc_free(arg);
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}
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static int ares_osmo_fd_cb(struct osmo_fd *fd, unsigned int what)
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{
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LOGP(DGPRS, LOGL_DEBUG, "C-ares fd(%d) ready(%d)\n", fd->fd, what);
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ares_process_fd(sgsn->ares_channel,
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(what & BSC_FD_READ) ? fd->fd : ARES_SOCKET_BAD,
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(what & BSC_FD_WRITE) ? fd->fd : ARES_SOCKET_BAD);
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osmo_ares_reschedule(sgsn);
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return 0;
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}
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static void ares_timeout_cb(void *data)
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{
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struct sgsn_instance *sgsn = data;
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LOGP(DGPRS, LOGL_DEBUG, "C-ares triggering timeout\n");
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ares_process_fd(sgsn->ares_channel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
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osmo_ares_reschedule(sgsn);
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}
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static void osmo_ares_reschedule(struct sgsn_instance *sgsn)
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{
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struct timeval *timeout, tv;
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osmo_timer_del(&sgsn->ares_timer);
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timeout = ares_timeout(sgsn->ares_channel, NULL, &tv);
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if (timeout) {
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sgsn->ares_timer.cb = ares_timeout_cb;
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sgsn->ares_timer.data = sgsn;
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LOGP(DGPRS, LOGL_DEBUG, "C-ares scheduling timeout %llu.%llu\n",
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(unsigned long long) tv.tv_sec,
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(unsigned long long) tv.tv_usec);
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osmo_timer_schedule(&sgsn->ares_timer, tv.tv_sec, tv.tv_usec);
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}
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}
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static void setup_ares_osmo_fd(void *data, int fd, int read, int write)
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{
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struct cares_event_fd *ufd, *tmp;
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/* delete the entry */
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if (read == 0 && write == 0) {
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llist_for_each_entry_safe(ufd, tmp, &sgsn->ares_fds, head) {
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if (ufd->fd.fd != fd)
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continue;
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LOGP(DGPRS, LOGL_DEBUG,
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"Removing C-ares watched fd (%d)\n", fd);
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osmo_fd_unregister(&ufd->fd);
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llist_del(&ufd->head);
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talloc_free(ufd);
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return;
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}
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}
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/* Search for the fd or create a new one */
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llist_for_each_entry(ufd, &sgsn->ares_fds, head) {
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if (ufd->fd.fd != fd)
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continue;
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LOGP(DGPRS, LOGL_DEBUG, "Updating C-ares fd (%d)\n", fd);
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goto update_fd;
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}
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LOGP(DGPRS, LOGL_DEBUG, "Registering C-ares fd (%d)\n", fd);
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ufd = talloc_zero(tall_bsc_ctx, struct cares_event_fd);
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ufd->fd.fd = fd;
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ufd->fd.cb = ares_osmo_fd_cb;
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ufd->fd.data = data;
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if (osmo_fd_register(&ufd->fd) != 0)
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LOGP(DGPRS, LOGL_ERROR, "Failed to register C-ares fd (%d)\n", fd);
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llist_add(&ufd->head, &sgsn->ares_fds);
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update_fd:
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if (read)
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ufd->fd.when |= BSC_FD_READ;
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else
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ufd->fd.when &= ~BSC_FD_READ;
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if (write)
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ufd->fd.when |= BSC_FD_WRITE;
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else
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ufd->fd.when &= ~BSC_FD_WRITE;
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osmo_ares_reschedule(sgsn);
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}
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int sgsn_ares_query(struct sgsn_instance *sgsn, const char *name,
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ares_host_callback cb, void *data)
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{
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struct cares_cb_data *cb_data;
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cb_data = talloc_zero(tall_bsc_ctx, struct cares_cb_data);
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cb_data->cb = cb;
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cb_data->data = data;
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ares_gethostbyname(sgsn->ares_channel, name, AF_INET, ares_cb, cb_data);
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osmo_ares_reschedule(sgsn);
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return 0;
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}
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int sgsn_ares_init(struct sgsn_instance *sgsn)
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{
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struct ares_options options;
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int optmask;
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int rc;
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INIT_LLIST_HEAD(&sgsn->ares_fds);
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memset(&options, 0, sizeof(options));
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options.sock_state_cb = setup_ares_osmo_fd;
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options.sock_state_cb_data = sgsn;
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optmask = ARES_OPT_FLAGS | ARES_OPT_SOCK_STATE_CB | ARES_OPT_DOMAINS;
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if (sgsn->ares_servers)
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optmask |= ARES_OPT_SERVERS;
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ares_library_init(ARES_LIB_INIT_ALL);
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rc = ares_init_options(&sgsn->ares_channel, &options, optmask);
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if (rc != ARES_SUCCESS)
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return rc;
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if (sgsn->ares_servers)
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rc = ares_set_servers(sgsn->ares_channel, sgsn->ares_servers);
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return rc;
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}
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osmo_static_assert(ARES_SUCCESS == 0, ares_success_zero);
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