sgsn: Integrate c-ares with the osmocom event loop

c-ares is an asynchronous DNS resolver and we need it to
resolve the GGSN address. This is integrating the library
into our infrastructure. We will create and maintain a list
of registered FDs (c-ares is currently only using one of
them) and (re-)schedule the timer after events occurred.
changes/88/3188/1
Holger Hans Peter Freyther 8 years ago
parent ccd2312d10
commit 66e7106d39
  1. 5
      openbsc/configure.ac
  2. 14
      openbsc/include/openbsc/sgsn.h
  3. 15
      openbsc/src/gprs/Makefile.am
  4. 168
      openbsc/src/gprs/sgsn_ares.c

@ -79,6 +79,11 @@ PKG_CHECK_MODULES(LIBGTP, libgtp, , found_libgtp=no)
AM_CONDITIONAL(HAVE_LIBGTP, test "$found_libgtp" = yes)
AC_SUBST(found_libgtp)
found_libcares=yes
PKG_CHECK_MODULES([LIBCARES], [libcares], [], [found_libcares=no])
AM_CONDITIONAL(HAVE_LIBCARES, test "$found_libcares" = yes)
AC_SUBST(found_libcares)
dnl checks for header files
AC_HEADER_STDC
AC_CHECK_HEADERS(dahdi/user.h,,AC_MSG_WARN(DAHDI input driver will not be built))

@ -7,6 +7,8 @@
#include <osmocom/gprs/gprs_ns.h>
#include <openbsc/gprs_sgsn.h>
#include <ares.h>
struct gprs_gsup_client;
enum sgsn_auth_policy {
@ -58,6 +60,11 @@ struct sgsn_instance {
struct gprs_gsup_client *gsup_client;
/* LLME inactivity timer */
struct osmo_timer_list llme_timer;
/* c-ares event loop integration */
struct osmo_timer_list ares_timer;
struct llist_head ares_fds;
ares_channel ares_channel;
};
extern struct sgsn_instance *sgsn;
@ -99,4 +106,11 @@ int sndcp_llunitdata_ind(struct msgb *msg, struct gprs_llc_lle *lle,
*/
int sgsn_cdr_init(struct sgsn_instance *sgsn);
/*
* C-ARES related functionality
*/
int sgsn_ares_init(struct sgsn_instance *sgsn);
int sgsn_ares_query(struct sgsn_instance *sgsm, const char *name, ares_host_callback cb, void *data);
#endif

@ -1,16 +1,19 @@
AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
AM_CFLAGS=-Wall -fno-strict-aliasing $(LIBOSMOCORE_CFLAGS) \
$(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(LIBOSMOCTRL_CFLAGS) \
$(LIBOSMOABIS_CFLAGS) $(LIBOSMOGB_CFLAGS) $(COVERAGE_CFLAGS)
$(LIBOSMOABIS_CFLAGS) $(LIBOSMOGB_CFLAGS) $(COVERAGE_CFLAGS) \
$(LIBCARES_CFLAGS)
OSMO_LIBS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) \
$(LIBOSMOCTRL_LIBS) $(LIBOSMOGB_LIBS)
noinst_HEADERS = gprs_sndcp.h
if HAVE_LIBGTP
bin_PROGRAMS = osmo-gbproxy osmo-sgsn
else
bin_PROGRAMS = osmo-gbproxy
if HAVE_LIBGTP
if HAVE_LIBCARES
bin_PROGRAMS += osmo-sgsn
endif
endif
osmo_gbproxy_SOURCES = gb_proxy.c gb_proxy_main.c gb_proxy_vty.c \
@ -24,7 +27,7 @@ osmo_sgsn_SOURCES = gprs_gmm.c gprs_sgsn.c gprs_sndcp.c gprs_sndcp_vty.c \
gprs_llc.c gprs_llc_parse.c gprs_llc_vty.c crc24.c \
sgsn_ctrl.c sgsn_auth.c gprs_subscriber.c \
gprs_gsup_messages.c gprs_utils.c gprs_gsup_client.c \
gsm_04_08_gprs.c sgsn_cdr.c
gsm_04_08_gprs.c sgsn_cdr.c sgsn_ares.c
osmo_sgsn_LDADD = \
$(top_builddir)/src/libcommon/libcommon.a \
-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) -lrt
-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) $(LIBCARES_LIBS) -lrt

@ -0,0 +1,168 @@
/* C-ARES DNS resolver integration */
/*
* (C) 2015 by Holger Hans Peter Freyther
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <openbsc/sgsn.h>
#include <openbsc/debug.h>
#include <netdb.h>
struct cares_event_fd {
struct llist_head head;
struct osmo_fd fd;
};
struct cares_cb_data {
ares_host_callback cb;
void *data;
};
static void osmo_ares_reschedule(struct sgsn_instance *sgsn);
static void ares_cb(void *_arg, int status, int timeouts, struct hostent *hostent)
{
struct cares_cb_data *arg = _arg;
arg->cb(arg->data, status, timeouts, hostent);
osmo_ares_reschedule(sgsn);
talloc_free(arg);
}
static int ares_osmo_fd_cb(struct osmo_fd *fd, unsigned int what)
{
LOGP(DGPRS, LOGL_DEBUG, "C-ares fd(%d) ready(%d)\n", fd->fd, what);
ares_process_fd(sgsn->ares_channel,
(what & BSC_FD_READ) ? fd->fd : ARES_SOCKET_BAD,
(what & BSC_FD_WRITE) ? fd->fd : ARES_SOCKET_BAD);
osmo_ares_reschedule(sgsn);
return 0;
}
static void ares_timeout_cb(void *data)
{
struct sgsn_instance *sgsn = data;
LOGP(DGPRS, LOGL_DEBUG, "C-ares triggering timeout\n");
ares_process_fd(sgsn->ares_channel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
osmo_ares_reschedule(sgsn);
}
static void osmo_ares_reschedule(struct sgsn_instance *sgsn)
{
struct timeval *timeout, tv;
osmo_timer_del(&sgsn->ares_timer);
timeout = ares_timeout(sgsn->ares_channel, NULL, &tv);
if (timeout) {
sgsn->ares_timer.cb = ares_timeout_cb;
sgsn->ares_timer.data = sgsn;
LOGP(DGPRS, LOGL_DEBUG, "C-ares scheduling timeout %llu.%llu\n",
(unsigned long long) tv.tv_sec,
(unsigned long long) tv.tv_usec);
osmo_timer_schedule(&sgsn->ares_timer, tv.tv_sec, tv.tv_usec);
}
}
static void setup_ares_osmo_fd(void *data, int fd, int read, int write)
{
struct cares_event_fd *ufd, *tmp;
/* delete the entry */
if (read == 0 && write == 0) {
llist_for_each_entry_safe(ufd, tmp, &sgsn->ares_fds, head) {
if (ufd->fd.fd != fd)
continue;
LOGP(DGPRS, LOGL_DEBUG,
"Removing C-ares watched fd (%d)\n", fd);
osmo_fd_unregister(&ufd->fd);
llist_del(&ufd->head);
talloc_free(ufd);
return;
}
}
/* Search for the fd or create a new one */
llist_for_each_entry(ufd, &sgsn->ares_fds, head) {
if (ufd->fd.fd != fd)
continue;
LOGP(DGPRS, LOGL_DEBUG, "Updating C-ares fd (%d)\n", fd);
goto update_fd;
}
LOGP(DGPRS, LOGL_DEBUG, "Registering C-ares fd (%d)\n", fd);
ufd = talloc_zero(tall_bsc_ctx, struct cares_event_fd);
ufd->fd.fd = fd;
ufd->fd.cb = ares_osmo_fd_cb;
ufd->fd.data = data;
osmo_fd_register(&ufd->fd);
llist_add(&ufd->head, &sgsn->ares_fds);
update_fd:
if (read)
ufd->fd.when |= BSC_FD_READ;
else
ufd->fd.when &= ~BSC_FD_READ;
if (write)
ufd->fd.when |= BSC_FD_WRITE;
else
ufd->fd.when &= ~BSC_FD_WRITE;
osmo_ares_reschedule(sgsn);
}
int sgsn_ares_query(struct sgsn_instance *sgsn, const char *name,
ares_host_callback cb, void *data)
{
struct cares_cb_data *cb_data;
cb_data = talloc_zero(tall_bsc_ctx, struct cares_cb_data);
cb_data->cb = cb;
cb_data->data = data;
ares_gethostbyname(sgsn->ares_channel, name, AF_INET, ares_cb, cb_data);
osmo_ares_reschedule(sgsn);
return 0;
}
int sgsn_ares_init(struct sgsn_instance *sgsn)
{
struct ares_options options;
int optmask;
int rc;
INIT_LLIST_HEAD(&sgsn->ares_fds);
memset(&options, 0, sizeof(options));
options.sock_state_cb = setup_ares_osmo_fd;
options.sock_state_cb_data = sgsn;
optmask = ARES_OPT_FLAGS | ARES_OPT_SOCK_STATE_CB;
/*| ARES_OPT_SERVERS ... TODO..*/
ares_library_init(ARES_LIB_INIT_ALL);
rc = ares_init_options(&sgsn->ares_channel, &options, optmask);
return rc;
}
osmo_static_assert(ARES_SUCCESS == 0, ares_success_zero);
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