Add synfake option

args.c

@@ -23,6 +23,7 @@ struct config_t config = {
 	.use_ipv6 = 1,
 	.fakeseq_offset = 10000,
 	.mark = DEFAULT_RAWSOCKET_MARK,
+	.synfake = 0,
 
 	.sni_detection = SNI_DETECTION_PARSE,
 
@@ -69,19 +70,21 @@ struct config_t config = {
 #define OPT_NO_IPV6		20
 #define OPT_FAKE_SEQ_OFFSET	21
 #define OPT_PACKET_MARK 	22
+#define OPT_SYNFAKE	 	23
 #define OPT_SEG2DELAY 		5
 #define OPT_THREADS 		6
 #define OPT_SILENT 		7
 #define OPT_NO_GSO 		8
 #define OPT_QUEUE_NUM		9
 
-#define OPT_MAX OPT_PACKET_MARK 
+#define OPT_MAX OPT_SYNFAKE
 
 static struct option long_opt[] = {
 	{"help",		0, 0, 'h'},
 	{"version",		0, 0, 'v'},
 	{"sni-domains",		1, 0, OPT_SNI_DOMAINS},
 	{"fake-sni",		1, 0, OPT_FAKE_SNI},
+	{"synfake",		1, 0, OPT_SYNFAKE},
 	{"fake-sni-seq-len",	1, 0, OPT_FAKE_SNI_SEQ_LEN},
 	{"faking-strategy",	1, 0, OPT_FAKING_STRATEGY},
 	{"fake-seq-offset",	1, 0, OPT_FAKE_SEQ_OFFSET},
@@ -141,6 +144,7 @@ void print_usage(const char *argv0) {
 	printf("\t--fake-seq-offset=<offset>\n");
 	printf("\t--faking-ttl=<ttl>\n");
 	printf("\t--faking-strategy={randseq|ttl|tcp_check|pastseq}\n");
+	printf("\t--synfake={1|0}\n");
 	printf("\t--frag={tcp,ip,none}\n");
 	printf("\t--frag-sni-reverse={0|1}\n");
 	printf("\t--frag-sni-faked={0|1}\n");
@@ -310,6 +314,16 @@ int parse_args(int argc, char *argv[]) {
 			}
 
 			config.fk_winsize = num;
+			break;
+		case OPT_SYNFAKE:
+			if (strcmp(optarg, "1") == 0) {
+				config.synfake = 1;
+			} else if (strcmp(optarg, "0") == 0) {
+				config.synfake = 0;
+			} else {
+				goto invalid_opt;
+			}
+
 			break;
 		case OPT_SEG2DELAY:
 			num = parse_numeric_option(optarg);
@@ -420,6 +434,10 @@ void print_welcome() {
 		printf("Response TCP window will be set to %d with the appropriate scale\n", config.fk_winsize);
 	}
 
+	if (config.synfake) {
+		printf("Fake SYN payload will be sent with each TCP request SYN packet\n");
+	}
+
 
 	if (config.use_gso) {
 		printf("GSO is enabled\n");