libconvert: send cookie TLV on client side

It is now possible to send a cookie TLV from the client using libconvert.
New tests have been added to check that the expected Cookie message is
sent and the Cookie TLV error is properly received and understood.

Signed-off-by: Pol Nicolaï <[email protected]>
Change-Id: I51fe5dce0bc1d24c10808b44d906224a91a82bab

convert_client.c

@@ -76,7 +76,8 @@ static LIST_HEAD(socket_htbl_t, socket_state) _socket_htable[NUM_BUCKETS];
 static pthread_mutex_t _socket_htable_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 static struct addrinfo *_converter_addr;
-static const char *	_convert_port = CONVERT_PORT;
+static const char *	_convert_port	= CONVERT_PORT;
+static const char *	_convert_cookie = NULL;
 
 static FILE *		_log;
 static pthread_mutex_t	_log_mutex = PTHREAD_MUTEX_INITIALIZER;
@@ -175,6 +176,12 @@ _redirect_connect_tlv(uint8_t *buf, size_t buf_len, struct sockaddr *addr)
 
 	opts.flags = CONVERT_F_CONNECT;
 
+	if (_convert_cookie) {
+		opts.flags		|= CONVERT_F_COOKIE;
+		opts.cookie_len		= strlen(_convert_cookie);
+		opts.cookie_data	= (uint8_t *)_convert_cookie;
+	}
+
 	switch (addr->sa_family) {
 	case AF_INET: {
 		struct sockaddr_in *in = (struct sockaddr_in *)addr;
@@ -543,6 +550,7 @@ _validate_parameters(char *err_buf, size_t len)
 {
 	const char *	convert_addr	= getenv("CONVERT_ADDR");
 	const char *	convert_port	= getenv("CONVERT_PORT");
+	const char *	convert_cookie	= getenv("CONVERT_COOKIE");
 
 	if (!convert_addr) {
 		snprintf(err_buf, len,
@@ -565,15 +573,20 @@ _validate_parameters(char *err_buf, size_t len)
 			_convert_port = convert_port;
 	}
 
+	if (convert_cookie)
+		_convert_cookie = convert_cookie;
+
 	/* resolve address */
 	if (getaddrinfo(convert_addr, _convert_port, NULL,
 	                &_converter_addr) != 0) {
 		snprintf(err_buf, len, "unable to resolve '%s'", convert_addr);
 		return -1;
 	}
 
-	log_info("connecting to convert service at %s:%s",
-	         convert_addr, _convert_port);
+	log_info("connecting to convert service at %s:%s%s%s",
+	         convert_addr, _convert_port,
+	         _convert_cookie ? " with cookie: " : "",
+	         _convert_cookie ? : "");
 
 	return 0;
 }

tests/CMakeLists.txt

@@ -25,7 +25,7 @@ add_test(NAME check_convert_util
 set(TEST_WRAPPER "${PROJECT_SOURCE_DIR}/tests/test-wrapper")
 
 foreach(TEST_CMD "curl" "wget")
-    foreach(TEST_TYPE "test_ok" "test_error")
+    foreach(TEST_TYPE "test_ok" "test_error" "test_cookie_ok" "test_cookie_error")
         set (test_name "${TEST_CMD}-${TEST_TYPE}")
 
         add_test(NAME "${test_name}"

tests/check_convert_util.c

@@ -279,7 +279,7 @@ START_TEST (test_convert_parse_tlvs_cookie) {
 
 	for (i = 0; i < cookie_len; ++i)
 		ck_assert_msg(opts->cookie_data[i] == cookie->opaque[i],
-		              "Should return exact copy TCP options");
+		              "Should return exact cookie value");
 
 	convert_free_opts(opts);
 	free(buff);

tests/converter_mock.py

@@ -53,7 +53,30 @@ def run(self, converter):
             converter.recv_end_seq += 1
         payload = pkt.getlayer(Raw)
         if payload:
-            converter.recv_end_seq += len(payload.load)
+            payload = payload.load
+
+            converter.recv_end_seq += len(payload)
+
+            # For the moment, we assume the TLV connect contains the header (4 bytes)
+            # and the TLV Connect (4 + 16 bytes). The cookie is then at the offset 24.
+            cookie_flag_offset = 24
+
+            # The cookie will only be received in the syn pkt.
+            if tcp.flags.S and len(payload) > cookie_flag_offset and bytes(payload)[cookie_flag_offset] == 0x16:
+
+                # The cookie TLV is as follows: 1 byte flag + 1 byte TLV length
+                # + 2 byte zeros, then Cookie data
+                cookie_size_offset = cookie_flag_offset + 1
+                cookie_data_offset = cookie_flag_offset + 4
+
+                # Length is given in 32-bit words, and includes flag byte + length
+                # byte and the 2 bytes of zeros.
+                cookie_data_size = (bytes(payload)[cookie_size_offset] - 1) * 4
+
+                cookie_data_offset_end = cookie_data_offset + cookie_data_size
+
+                cookie_bytes = bytes(payload)[cookie_data_offset:cookie_data_offset_end]
+                converter.cookie = cookie_bytes.decode('utf-8').rstrip('\x00')
 
 
 class RecvSyn(RecvPkt):
@@ -98,6 +121,18 @@ def run(self, converter):
         super(SendSynAck, self).run(converter)
 
 
+class SendSynAckCheckCookie(SendSynAck):
+    def __init__(self, payload, cookie):
+        SendSynAck.__init__(self, payload=payload)
+        self.cookie = cookie
+
+    def run(self, converter):
+        # Check cookie value
+        if self.cookie != converter.cookie:
+            raise Exception("Wrong cookie '{}' instead of '{}'".format(converter.cookie, self.cookie))
+        super(SendSynAckCheckCookie, self).run(converter)
+
+
 class SendHTTPResp(SendPkt):
     def __init__(self, data):
         payload = "HTTP/1.1 200 OK\r\n"

tests/test-wrapper

@@ -13,6 +13,7 @@ export TEST_CONVERT_LOG=convert.log
 export TEST_OUTPUT_LOG=output.log
 export TEST_CONVERT_MOCK_LOG=convert_mock.log
 export TEST_VALIDATE_LOG=validate.log
+export TEST_CONVERT_COOKIE="cookie"
 
 SCAPY_PID=
 
@@ -60,7 +61,11 @@ sleep 1
 
 
 COMMAND=$(test_step run_cmd)
-CONVERT_LOG=${TEST_CONVERT_LOG} CONVERT_ADDR=127.0.0.1 LD_PRELOAD="../libconvert_client.so" ${COMMAND} > ${TEST_OUTPUT_LOG} 2>&1 || true
+CONVERT_LOG=${TEST_CONVERT_LOG} \
+    CONVERT_ADDR=127.0.0.1 \
+    CONVERT_COOKIE=${TEST_CONVERT_COOKIE} \
+    LD_PRELOAD="../libconvert_client.so" \
+        ${COMMAND} > ${TEST_OUTPUT_LOG} 2>&1 || true
 
 ret=$(test_step validate 2>&1 | tee ${TEST_VALIDATE_LOG})
 [ "${ret}" == "" ] && RETURN_CODE=0

tests/test_cookie_error.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+
+from converter_mock import *
+from test_lib import *
+
+
+class TestCookieError(TestInstance):
+    def run(self):
+        converter = Convert(tlvs=[ConvertTLV_Error(error_code=3)])
+        print(converter.build())
+        cookie = self.get_cookie()
+
+        class MockConverterCookieError(MockConverter):
+            actions = [RecvSyn(), SendSynAckCheckCookie(converter.build(), cookie), Wait(1), SendPkt(flags='R')]
+        MockConverterCookieError()
+
+    def validate(self):
+        self.assert_log_contains("received TLV error: 3")
+
+
+TestCookieError()

tests/test_cookie_ok.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+
+from converter_mock import *
+from test_lib import *
+
+
+class TestCookieOK(TestInstance):
+    def run(self):
+        cookie = self.get_cookie()
+        class MockConverterCookieOK(MockConverter):
+            actions = [RecvSyn(), SendSynAckCheckCookie(Convert().build(), cookie), RecvHTTPGet(
+            ), SendHTTPResp("HELLO, WORLD!"), SendPkt(flags='RA')]
+        MockConverterCookieOK()
+
+    def validate(self):
+        self.assert_result("HELLO, WORLD!")
+
+
+TestCookieOK()

tests/test_lib.py

@@ -35,6 +35,9 @@ def _get_log(self):
         with open(os.environ["TEST_CONVERT_LOG"]) as f:
             return f.read()
 
+    def get_cookie(self):
+        return os.environ["TEST_CONVERT_COOKIE"]
+
     def assert_result(self, result):
         assert result in self._get_result(), "Couldn't find '{}' in output".format(result)