trx_toolkit: Add cmdline arg to set bind addr

Previous hardcoded default of 0.0.0.0 was inappropiate in some
scenarios, as it sets the SRC addr of the packets sent through the
socket based on the routing.

For instance, if iface IF1 has assigned two IP addresses A and B,
A being the first addr of the interface, and osmo-bts-trx is
configured with "osmotrx ip local A" and "osmotrx ip remote B",
the following happens:

  CMD POWER OFF src=A:5801 dst=B:5701
  RSP POWER OFF src=A:5701 dst=A:5701 <-- A is assigned as src addr.

But osmo-bts-trx is waiting for packets from B:5701, and the packet
is dropped with ICMP Unreachable. If addr binding is forced in
fake_trx to B, then everthing's fine.

Let's extend the UDPLink in order to allow manual, but optional
setting of bind address, and add a corresponding cmdline
argument to all executables.

Change-Id: I7be18fef40967fb7551f4115f22cbbd9cdb0840d

1 files changed, 9 insertions, 4 deletions

diff --git a/src/target/trx_toolkit/ctrl_cmd.py b/src/target/trx_toolkit/ctrl_cmd.py
index 0791f85c..e56105a8 100755
--- a/src/target/trx_toolkit/ctrl_cmd.py
+++ b/src/target/trx_toolkit/ctrl_cmd.py
@@ -36,6 +36,7 @@ from udp_link import UDPLink
 class Application:
 	# Application variables
 	remote_addr = "127.0.0.1"
+	bind_addr = "0.0.0.0"
 	base_port = 5700
 	bind_port = 0
 	fuzzing = False
@@ -48,8 +49,8 @@ class Application:
 		signal.signal(signal.SIGINT, self.sig_handler)
 
 		# Init UDP connection
-		self.ctrl_link = UDPLink(self.remote_addr,
-			self.base_port + 1, self.bind_port)
+		self.ctrl_link = UDPLink(self.remote_addr, self.base_port + 1,
+			self.bind_addr, self.bind_port)
 
 		# Debug print
 		print("[i] Init CTRL interface (%s)" \
@@ -64,9 +65,10 @@ class Application:
 			 "  -r --remote-addr    Set remote address (default %s)\n"   \
 			 "  -p --base-port      Set base port number (default %d)\n" \
 			 "  -P --bind-port      Set local port number (default: random)\n" \
+			 "  -b --bind-addr      Set local address (default %s)\n" \
 			 "  -f --fuzzing        Send raw payloads (without CMD)\n"   \
 
-		print(s % (self.remote_addr, self.base_port))
+		print(s % (self.remote_addr, self.base_port, self.bind_addr))
 
 		if msg is not None:
 			print(msg)
@@ -74,12 +76,13 @@ class Application:
 	def parse_argv(self):
 		try:
 			opts, args = getopt.getopt(sys.argv[1:],
-				"r:p:P:fh",
+				"r:p:P:b:fh",
 				[
 					"help",
 					"fuzzing",
 					"base-port=",
 					"bind-port=",
+					"bind-addr=",
 					"remote-addr=",
 				])
 		except getopt.GetoptError as err:
@@ -93,6 +96,8 @@ class Application:
 
 			elif o in ("-r", "--remote-addr"):
 				self.remote_addr = v
+			elif o in ("-b", "--bind-addr"):
+				self.bind_addr = v
 			elif o in ("-p", "--base-port"):
 				self.base_port = int(v)
 			elif o in ("-P", "--bind-port"):