finish GSMTAP output support (and enable it)

Layer2 now sends GSMTAP packets to a UDP port on localhost, where
wireshark can pick them up in realtime and display them.

4 files changed, 38 insertions, 6 deletions

diff --git a/src/host/layer2/src/gsmtap_util.c b/src/host/layer2/src/gsmtap_util.c
index 9abc14bb..79c5c5f6 100644
--- a/src/host/layer2/src/gsmtap_util.c
+++ b/src/host/layer2/src/gsmtap_util.c
@@ -58,11 +58,11 @@ int gsmtap_sendmsg(uint8_t ts, uint16_t arfcn, uint32_t fn,
 	gh->hdr_len = sizeof(*gh)/4;
 	gh->type = GSMTAP_TYPE_UM;
 	gh->timeslot = ts;
-	gh->arfcn = arfcn;
+	gh->arfcn = htons(arfcn);
 	gh->noise_db = 0;
 	gh->signal_db = 0;
-	gh->frame_number = fn;
-	gh->burst_type = 0;
+	gh->frame_number = htonl(fn);
+	gh->burst_type = GSMTAP_BURST_NORMAL;
 	gh->antenna_nr = 0;
 
 	dst = msgb_put(msg, len);
@@ -105,10 +105,29 @@ static int gsmtap_fd_cb(struct bsc_fd *fd, unsigned int flags)
 	return 0;
 }
 
-int gsmtap_init(struct sockaddr_in *sin)
+int gsmtap_init(void)
 {
+	int rc;
+	struct sockaddr_in sin;
+
+	sin.sin_family = AF_INET;
+	sin.sin_port = htons(GSMTAP_UDP_PORT);
+	inet_aton("127.0.0.1", &sin.sin_addr);
+
 	/* FIXME: create socket */
-	//gsmtap_bfd.fd = 
+	rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (rc < 0) {
+		perror("creating UDP socket");
+		return rc;
+	}
+	gsmtap_bfd.fd = rc;
+	rc = connect(rc, (struct sockaddr *)&sin, sizeof(sin));
+	if (rc < 0) {
+		perror("connecting UDP socket");
+		close(gsmtap_bfd.fd);
+		gsmtap_bfd.fd = 0;
+		return rc;
+	}
 
 	gsmtap_bfd.when = BSC_FD_WRITE;
 	gsmtap_bfd.cb = gsmtap_fd_cb;
diff --git a/src/host/layer2/src/gsmtap_util.h b/src/host/layer2/src/gsmtap_util.h
index b71c2e8a..3599c33d 100644
--- a/src/host/layer2/src/gsmtap_util.h
+++ b/src/host/layer2/src/gsmtap_util.h
@@ -4,7 +4,7 @@
 #include <stdint.h>
 #include <netinet/in.h>
 
-int gsmtap_init(struct sockaddr_in *sin);
+int gsmtap_init(void);
 
 /* receive a message from L1/L2 and put it in GSMTAP */
 int gsmtap_sendmsg(uint8_t ts, uint16_t arfcn, uint32_t fn,
diff --git a/src/host/layer2/src/layer2_main.c b/src/host/layer2/src/layer2_main.c
index c84cce49..5e155223 100644
--- a/src/host/layer2/src/layer2_main.c
+++ b/src/host/layer2/src/layer2_main.c
@@ -38,6 +38,8 @@
 #include <errno.h>
 #include <fcntl.h>
 
+#include "gsmtap_util.h"
+
 #define GSM_L2_LENGTH 256
 
 static void *l2_ctx = NULL;
@@ -157,6 +159,7 @@ int main(int argc, char **argv)
 {
 	int rc;
 	struct sockaddr_un local;
+	struct sockaddr_in gsmtap;
 
 	l2_ctx = talloc_named_const(NULL, 1, "layer2 context");
 
@@ -196,6 +199,12 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	rc = gsmtap_init();
+	if (rc < 0) {
+		fprintf(stderr, "Failed during gsmtap_init()\n");
+		exit(1);
+	}
+
 	while (1) {
 		bsc_select_main(0);
 	}
diff --git a/src/host/layer2/src/osmocom_layer2.c b/src/host/layer2/src/osmocom_layer2.c
index 0be0a4c4..52b0fdab 100644
--- a/src/host/layer2/src/osmocom_layer2.c
+++ b/src/host/layer2/src/osmocom_layer2.c
@@ -29,6 +29,7 @@
 #include <stdint.h>
 #include <l1a_l23_interface.h>
 
+#include "gsmtap_util.h"
 
 static struct msgb *osmo_l1_alloc(uint8_t msg_type)
 {
@@ -174,6 +175,9 @@ static int osmo_l2_ccch_data(struct osmocom_ms *ms, struct msgb *msg)
 	       hexdump(ccch->data, sizeof(ccch->data)), ccch->data[2]);
 
 	dump_bcch(dl->time.tc, ccch->data);
+	/* send CCCH data via GSMTAP */
+	gsmtap_sendmsg(0, dl->band_arfcn, dl->time.fn, ccch->data,
+			sizeof(ccch->data));
 	return 0;
 }