gsmtap: rework GSMTAP API to be more future-proof

* use write_queue where applicable
* provide functions that work on raw FD and those with osmo_fd
* add support for multiple gsmtap instances (no global variables)

3 files changed, 54 insertions, 10 deletions

diff --git a/include/osmocom/core/Makefile.am b/include/osmocom/core/Makefile.am
index 36988733..3c30362c 100644
--- a/include/osmocom/core/Makefile.am
+++ b/include/osmocom/core/Makefile.am
@@ -1,5 +1,5 @@
 osmocore_HEADERS = signal.h linuxlist.h timer.h select.h msgb.h bits.h \
-		   bitvec.h statistics.h utils.h \
+		   bitvec.h statistics.h utils.h socket.h \
 		   gsmtap.h write_queue.h \
 		   logging.h rate_ctr.h gsmtap_util.h \
 		   plugin.h crc16.h panic.h process.h msgfile.h \
diff --git a/include/osmocom/core/gsmtap_util.h b/include/osmocom/core/gsmtap_util.h
index 785f5e58..f553c17a 100644
--- a/include/osmocom/core/gsmtap_util.h
+++ b/include/osmocom/core/gsmtap_util.h
@@ -2,24 +2,52 @@
 #define _GSMTAP_UTIL_H
 
 #include <stdint.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/select.h>
 
 /* convert RSL channel number to GSMTAP channel type */
 uint8_t chantype_rsl2gsmtap(uint8_t rsl_chantype, uint8_t rsl_link_id);
 
-/* receive a message from L1/L2 and put it in GSMTAP */
+/* generate msgb from data + metadata */
 struct msgb *gsmtap_makemsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type,
 			    uint8_t ss, uint32_t fn, int8_t signal_dbm,
 			    uint8_t snr, const uint8_t *data, unsigned int len);
 
-/* receive a message from L1/L2 and put it in GSMTAP */
-int gsmtap_sendmsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type, uint8_t ss,
-		   uint32_t fn, int8_t signal_dbm, uint8_t snr,
-		   const uint8_t *data, unsigned int len);
+/* one gsmtap instance */
+struct gsmtap_inst {
+	int ofd_wq_mode;
+	struct osmo_wqueue wq;
+	struct osmo_fd sink_ofd;
+};
 
-int gsmtap_init(uint32_t dst_ip);
+static inline int gsmtap_inst_fd(struct gsmtap_inst *gti)
+{
+	return gti->wq.bfd.fd;
+}
 
-/* Create a local 'gsmtap sink' avoiding the UDP packets being rejected
- * with ICMP reject messages */
-int gsmtap_sink_init(uint32_t bind_ip);
+/* Open a GSMTAP source (sending) socket, conncet it to host/port and
+ * return resulting fd */
+int gsmtap_source_init_fd(const char *host, uint16_t port);
+
+/* Add a local sink to an existing GSMTAP source and return fd */
+int gsmtap_source_add_sink_fd(int gsmtap_fd);
+
+/* Open GSMTAP source (sending) socket, connect it to host/port,
+ * allocate 'struct gsmtap_inst' and optionally osmo_fd/osmo_wqueue
+ * registration */
+struct gsmtap_inst *gsmtap_source_init(const char *host, uint16_t port,
+					int ofd_wq_mode);
+
+/* Add a local sink to an existing GSMTAP source instance */
+int gsmtap_source_add_sink(struct gsmtap_inst *gti);
+
+/* Send a msgb through a GSMTAP source */
+int gsmtap_sendmsg(struct gsmtap_inst *gti, struct msgb *msg);
+
+/* generate a message and send it via GSMTAP */
+int gsmtap_send(struct gsmtap_inst *gti, uint16_t arfcn, uint8_t ts,
+		uint8_t chan_type, uint8_t ss, uint32_t fn,
+		int8_t signal_dbm, uint8_t snr, const uint8_t *data,
+		unsigned int len);
 
 #endif /* _GSMTAP_UTIL_H */
diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h
new file mode 100644
index 00000000..3ede524b
--- /dev/null
+++ b/include/osmocom/core/socket.h
@@ -0,0 +1,16 @@
+#ifndef _OSMOCORE_SOCKET_H
+#define _OSMOCORE_SOCKET_H
+
+#include <stdint.h>
+#include <sys/socket.h>
+
+int osmo_sock_init(uint16_t family, uint16_t type, uint8_t proto,
+		   const char *host, uint16_t port, int connect0_bind1);
+
+int osmo_sock_init_sa(struct sockaddr *ss, uint16_t type,
+		      uint8_t proto, int connect0_bind1);
+
+/* determine if the given address is a local address */
+int osmo_sockaddr_is_local(struct sockaddr *addr, socklen_t addrlen);
+
+#endif /* _OSMOCORE_SOCKET_H */