From 66e7106d393368b2dd0d04c08f31781ed997380b Mon Sep 17 00:00:00 2001 From: Holger Hans Peter Freyther Date: Mon, 25 May 2015 01:21:50 +0800 Subject: [PATCH] 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. --- openbsc/configure.ac | 5 + openbsc/include/openbsc/sgsn.h | 14 +++ openbsc/src/gprs/Makefile.am | 15 +-- openbsc/src/gprs/sgsn_ares.c | 168 +++++++++++++++++++++++++++++++++ 4 files changed, 196 insertions(+), 6 deletions(-) create mode 100644 openbsc/src/gprs/sgsn_ares.c diff --git a/openbsc/configure.ac b/openbsc/configure.ac index 394972f46..fb6feb9b9 100644 --- a/openbsc/configure.ac +++ b/openbsc/configure.ac @@ -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)) diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h index 0f9a59f25..8e4d532bf 100644 --- a/openbsc/include/openbsc/sgsn.h +++ b/openbsc/include/openbsc/sgsn.h @@ -7,6 +7,8 @@ #include #include +#include + 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 diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am index 3d0282204..f46a40254 100644 --- a/openbsc/src/gprs/Makefile.am +++ b/openbsc/src/gprs/Makefile.am @@ -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 diff --git a/openbsc/src/gprs/sgsn_ares.c b/openbsc/src/gprs/sgsn_ares.c new file mode 100644 index 000000000..825b01c5b --- /dev/null +++ b/openbsc/src/gprs/sgsn_ares.c @@ -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 . + * + */ + +#include +#include + +#include + +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);