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-rw-r--r--src/gtphub/gtphub_ares.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/src/gtphub/gtphub_ares.c b/src/gtphub/gtphub_ares.c
new file mode 100644
index 00000000..87dc860c
--- /dev/null
+++ b/src/gtphub/gtphub_ares.c
@@ -0,0 +1,220 @@
+/* GTP Hub Implementation */
+
+/* (C) 2015 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * gtphub_ares.c.
+ *
+ * This file is kept separate so that these functions can be wrapped for
+ * gtphub_test.c. When a function and its callers are in the same compilational
+ * unit, the wrappability may be optimized away.
+ *
+ * Author: Neels Hofmeyr
+ *
+ * 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 <string.h>
+#include <unistd.h>
+
+#include <osmocom/sgsn/gtphub.h>
+#include <osmocom/sgsn/debug.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/gsm/apn.h>
+
+/* TODO split GRX ares from sgsn into a separate struct and allow use without
+ * globals. */
+#include <osmocom/sgsn/sgsn.h>
+extern struct sgsn_instance *sgsn;
+
+struct sgsn_instance sgsn_inst = { 0 };
+struct sgsn_instance *sgsn = &sgsn_inst;
+
+extern void *osmo_gtphub_ctx;
+
+int gtphub_ares_init(struct gtphub *hub)
+{
+ return sgsn_ares_init(sgsn);
+}
+
+struct ggsn_lookup {
+ struct llist_head entry;
+ struct expiring_item expiry_entry;
+
+ struct gtphub *hub;
+
+ char imsi_str[GSM23003_IMSI_MAX_DIGITS+1];
+ char apn_ni_str[GSM_APN_LENGTH];
+ char apn_oi_str[GSM_APN_LENGTH];
+ int have_3dig_mnc;
+};
+
+static int start_ares_query(struct ggsn_lookup *lookup);
+
+static void ggsn_lookup_cb(void *arg, int status, int timeouts,
+ struct hostent *hostent)
+{
+ struct ggsn_lookup *lookup = arg;
+ LOGP(DGTPHUB, LOGL_NOTICE, "ggsn_lookup_cb(%p / %p)", lookup,
+ &lookup->expiry_entry);
+
+ if (status != ARES_SUCCESS) {
+ LOGP(DGTPHUB, LOGL_ERROR, "DNS query failed.\n");
+
+ /* Need to try with three digits now */
+ if (!lookup->have_3dig_mnc) {
+ lookup->have_3dig_mnc = 1;
+ if (start_ares_query(lookup) == 0)
+ return;
+ }
+
+ LOGP(DGTPHUB, LOGL_ERROR, "Failed to resolve GGSN. (%p)\n",
+ lookup);
+ goto remove_from_queue;
+ }
+
+ struct gsn_addr resolved_addr;
+ if (hostent->h_length > sizeof(resolved_addr.buf)) {
+ LOGP(DGTPHUB, LOGL_ERROR, "Addr size too large: %d > %d\n",
+ (int)hostent->h_length, (int)sizeof(resolved_addr.buf));
+ goto remove_from_queue;
+ }
+
+ /* Get the first addr from the list */
+ char *addr0 = hostent->h_addr_list[0];
+ if (!addr0) {
+ LOGP(DGTPHUB, LOGL_ERROR, "No host address.\n");
+ goto remove_from_queue;
+ }
+
+ memcpy(resolved_addr.buf, addr0, hostent->h_length);
+ resolved_addr.len = hostent->h_length;
+
+ LOGP(DGTPHUB, LOGL_NOTICE, "resolved addr %s\n",
+ osmo_hexdump((unsigned char*)&resolved_addr,
+ sizeof(resolved_addr)));
+
+ gtphub_resolved_ggsn(lookup->hub, lookup->apn_oi_str, &resolved_addr,
+ gtphub_now());
+
+remove_from_queue:
+ LOGP(DGTPHUB, LOGL_ERROR, "Removing GGSN lookup. (%p / %p)\n", lookup,
+ &lookup->expiry_entry);
+ expiring_item_del(&lookup->expiry_entry);
+}
+
+static void make_addr_str(struct ggsn_lookup *lookup)
+{
+ char *apn_oi_str;
+ apn_oi_str = osmo_apn_qualify_from_imsi(lookup->imsi_str,
+ lookup->apn_ni_str,
+ lookup->have_3dig_mnc);
+ osmo_strlcpy(lookup->apn_oi_str, apn_oi_str,
+ sizeof(lookup->apn_oi_str));
+}
+
+static int start_ares_query(struct ggsn_lookup *lookup)
+{
+ LOGP(DGTPHUB, LOGL_DEBUG, "Going to query %s (%p / %p)\n",
+ lookup->apn_oi_str, lookup, &lookup->expiry_entry);
+
+ int rc = sgsn_ares_query(sgsn, lookup->apn_oi_str, ggsn_lookup_cb,
+ lookup);
+ if (rc != 0)
+ LOGP(DGTPHUB, LOGL_ERROR, "Failed to start ares query.\n");
+ return rc;
+}
+
+static void ggsn_lookup_del_cb(struct expiring_item *expi)
+{
+ struct ggsn_lookup *lookup;
+ lookup = container_of(expi, struct ggsn_lookup, expiry_entry);
+
+ LOGP(DGTPHUB, LOGL_NOTICE, "ggsn_lookup_del_cb(%p / %p)\n", lookup,
+ expi);
+
+ lookup->expiry_entry.del_cb = 0;
+ expiring_item_del(expi);
+
+ llist_del(&lookup->entry);
+ talloc_free(lookup);
+}
+
+struct gtphub_peer_port *gtphub_resolve_ggsn_addr(struct gtphub *hub,
+ const char *imsi_str,
+ const char *apn_ni_str)
+{
+ OSMO_ASSERT(imsi_str);
+ OSMO_ASSERT(apn_ni_str);
+
+ struct ggsn_lookup *lookup = talloc_zero(osmo_gtphub_ctx,
+ struct ggsn_lookup);
+ OSMO_ASSERT(lookup);
+
+ LOGP(DGTPHUB, LOGL_DEBUG, "Request to resolve IMSI"
+ " '%s' with APN-NI '%s' (%p / %p)\n",
+ imsi_str, apn_ni_str, lookup, &lookup->expiry_entry);
+
+ expiring_item_init(&lookup->expiry_entry);
+ lookup->hub = hub;
+
+ osmo_strlcpy(lookup->imsi_str, imsi_str, sizeof(lookup->imsi_str));
+ osmo_strlcpy(lookup->apn_ni_str, apn_ni_str,
+ sizeof(lookup->apn_ni_str));
+
+ make_addr_str(lookup);
+
+ struct ggsn_lookup *active;
+ llist_for_each_entry(active, &hub->ggsn_lookups, entry) {
+ if (strncmp(active->apn_oi_str, lookup->apn_oi_str,
+ sizeof(lookup->apn_oi_str)) == 0) {
+ LOGP(DGTPHUB, LOGL_DEBUG,
+ "Query already pending for %s\n",
+ lookup->apn_oi_str);
+ /* A query already pending. Just tip our hat. */
+ return NULL;
+ }
+ }
+
+ struct gtphub_resolved_ggsn *resolved;
+ llist_for_each_entry(resolved, &hub->resolved_ggsns, entry) {
+ if (strncmp(resolved->apn_oi_str, lookup->apn_oi_str,
+ sizeof(lookup->apn_oi_str)) == 0) {
+ LOGP(DGTPHUB, LOGL_DEBUG,
+ "GGSN resolved from cache: %s -> %s\n",
+ lookup->apn_oi_str,
+ gtphub_port_str(resolved->peer));
+ return resolved->peer;
+ }
+ }
+
+ /* Kick off a resolution, but so far return nothing. The hope is that
+ * the peer will resend the request (a couple of times), and by then
+ * the GGSN will be resolved. */
+ LOGP(DGTPHUB, LOGL_DEBUG,
+ "Sending out DNS query for %s..."
+ " (Returning failure, hoping for a retry once resolution"
+ " has concluded)\n",
+ lookup->apn_oi_str);
+
+ llist_add(&lookup->entry, &hub->ggsn_lookups);
+
+ lookup->expiry_entry.del_cb = ggsn_lookup_del_cb;
+ expiry_add(&hub->expire_quickly, &lookup->expiry_entry, gtphub_now());
+
+ start_ares_query(lookup);
+
+ return NULL;
+}