[nat] Connect to the MSC like the real BSC
Use the connect_to_msc method to connect to the MSC and
create structure to handle and forward messages to the
real BSC.
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index b5ba8ce..67db49a 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -24,6 +24,7 @@
#include <netinet/in.h>
#include <arpa/inet.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
@@ -32,10 +33,82 @@
#include <getopt.h>
#include <openbsc/debug.h>
+#include <openbsc/msgb.h>
+#include <openbsc/bsc_msc.h>
+#include <openbsc/ipaccess.h>
+#include <openbsc/abis_nm.h>
+#include <openbsc/talloc.h>
static const char *config_file = "openbsc.cfg";
static char *msc_address = "127.0.0.1";
static struct in_addr local_addr;
+static struct bsc_fd msc_connection;
+
+/*
+ * below are stubs we need to link
+ */
+int nm_state_event(enum nm_evt evt, u_int8_t obj_class, void *obj,
+ struct gsm_nm_state *old_state, struct gsm_nm_state *new_state)
+{
+ return -1;
+}
+
+void input_event(int event, enum e1inp_sign_type type, struct gsm_bts_trx *trx)
+{}
+
+int gsm0408_rcvmsg(struct msgb *msg, u_int8_t link_id)
+{
+ return -1;
+}
+
+/*
+ * Below is the handling of messages coming
+ * from the MSC and need to be forwarded to
+ * a real BSC.
+ */
+static void initialize_msc_if_needed()
+{
+ static int init = 0;
+ init = 1;
+
+ /* do we need to send a GSM 08.08 message here? */
+}
+
+static void forward_sccp_to_bts(struct msgb *msg)
+{
+ /* filter, drop, patch the message? */
+}
+
+static int ipaccess_msc_cb(struct bsc_fd *bfd, unsigned int what)
+{
+ int error;
+ struct msgb *msg = ipaccess_read_msg(bfd, &error);
+ struct ipaccess_head *hh;
+
+ if (!msg) {
+ if (error == 0) {
+ fprintf(stderr, "The connection to the MSC was lost, exiting\n");
+ exit(-2);
+ }
+
+ fprintf(stderr, "Failed to parse ip access message: %d\n", error);
+ return -1;
+ }
+
+ DEBUGP(DMSC, "MSG from MSC: %s proto: %d\n", hexdump(msg->data, msg->len), msg->l2h[0]);
+
+ /* handle base message handling */
+ hh = (struct ipaccess_head *) msg->data;
+ ipaccess_rcvmsg_base(msg, bfd);
+
+ /* initialize the networking. This includes sending a GSM08.08 message */
+ if (hh->proto == IPAC_PROTO_IPACCESS && msg->l2h[0] == IPAC_MSGT_ID_ACK)
+ initialize_msc_if_needed();
+ else if (hh->proto == IPAC_PROTO_SCCP)
+ forward_sccp_to_bts(msg);
+
+ return 0;
+}
static void print_usage()
{
@@ -103,13 +176,47 @@
}
}
+static void signal_handler(int signal)
+{
+ fprintf(stdout, "signal %u received\n", signal);
+
+ switch (signal) {
+ case SIGABRT:
+ /* in case of abort, we want to obtain a talloc report
+ * and then return to the caller, who will abort the process */
+ case SIGUSR1:
+ talloc_report_full(tall_bsc_ctx, stderr);
+ break;
+ default:
+ break;
+ }
+}
+
int main(int argc, char** argv)
{
+ int rc;
+
/* parse options */
handle_options(argc, argv);
/* seed the PRNG */
srand(time(NULL));
+ msc_connection.cb = ipaccess_msc_cb;
+ rc = connect_to_msc(&msc_connection, msc_address, 5000);
+ if (rc < 0) {
+ fprintf(stderr, "Opening the MSC connection failed.\n");
+ exit(1);
+ }
+
+ signal(SIGINT, &signal_handler);
+ signal(SIGABRT, &signal_handler);
+ signal(SIGUSR1, &signal_handler);
+ signal(SIGPIPE, SIG_IGN);
+
+ while (1) {
+ bsc_select_main(0);
+ }
+
return 0;
}