Added IMEI filtering and command line argument to strip Iridium SBD header

when writing files

src/wstationd.c

@@ -51,7 +51,7 @@ struct connection
 };
 
 
-static int write_connection(struct connection *);
+static int write_connection(struct connection *, int strip);
 
 void shutdown_handler(int sig)
 {
@@ -65,6 +65,8 @@ static void print_help()
 	fprintf(stdout, "  -l, --limit <limit>    Set concurrent connection limit (default: 128)\n");
 	fprintf(stdout, "  -p, --port <port>      Port to listen on (default: 10800)\n");
 	fprintf(stdout, "  -b, --bind <address>   Address to bind to (default: 0.0.0.0)\n");
+	fprintf(stdout, "  -i, --imei <imei list> Comma separated list of IMEIs to allow (default: all)\n");
+	fprintf(stdout, "  -s, --strip            Strip Iridium SBD header when writing files\n");
 	fprintf(stdout, "  -h, --help             Print this message and exit\n");
 	fprintf(stdout, "  -v, --version          Print version and exit\n");
 }
@@ -73,10 +75,12 @@ static void print_help()
 int main(int argc, char* argv[])
 {
 	const struct option longopts[] = {
+		{ "imei", required_argument, NULL, 'i' },
 		{ "limit", required_argument, NULL, 'l' },
 		{ "nodaemon", required_argument, NULL, 'd' },
 		{ "port", required_argument, NULL, 'p' },
 		{ "bind", required_argument, NULL, 'b' },
+		{ "strip", no_argument, NULL, 's' },
 		{ "version", no_argument, NULL, 'v' },
 		{ "help", no_argument, NULL, 'h' },
 		{ NULL, 0, NULL, 0 }
@@ -90,6 +94,11 @@ int main(int argc, char* argv[])
 	struct connection** conns = NULL;
 	struct pollfd* fds = NULL;
 
+	char *imei_list = NULL;
+	size_t imei_list_sz = 0;
+
+	int strip = 0;
+
 	if((exec_name = basename(argv[0])) == NULL){
 		fprintf(stderr, "%s: cannot get basename - %s\n",
 			exec_name, strerror(errno)
@@ -97,7 +106,7 @@ int main(int argc, char* argv[])
 		goto shutdown_error;
 	}
 
-	for(int ch; (ch = getopt_long(argc, argv, "l:b:p:dvh0", longopts, NULL)) != -1;){
+	for(int ch; (ch = getopt_long(argc, argv, "i:l:b:p:dsvh0", longopts, NULL)) != -1;){
 		switch(ch){
 			case 'd':
 				daemonize = 0;
@@ -112,6 +121,22 @@ int main(int argc, char* argv[])
 				}
 			break;
 
+			case 'i':
+				imei_list = argv[optind-1];
+				imei_list_sz = strlen(imei_list);
+
+				// If the user provides the word "all" as the only imei entry,
+				// remove the filter.
+				if(imei_list_sz == 3 && memcmp(imei_list, "all", 3) == 0){
+					imei_list_sz = 0;
+					imei_list = NULL;
+				}
+			break;
+
+			case 's':
+				strip = 1;
+			break;
+			
 			case 'p':
 				port = (int)strtol(optarg, NULL, 10);
 				if(port < 1 || port > 65535){
@@ -299,12 +324,32 @@ int main(int argc, char* argv[])
 						// Convert and add three bytes for the SBD header
 						ssize_t expected = (ssize_t)htons(sbd_sz) + 3;
 
-						// Iridium SBD format check. Is the protocol byte in place?
-						// Is the reported size the same as the actual size written
-						// in bytes? If so, write it out.
-						if(expected == conns[i-1]->len && conns[i-1]->buff[0] == 1){
-							write_connection(conns[i - 1]);
+						int ok = 1;
+						// Is the reported size the same as the actual size
+						// written in bytes?
+						if(expected != conns[i-1]->len) ok = 0;
+
+						// Is the protocol byte in place?
+						if(ok && conns[i-1]->buff[0] != 1) ok = 0;
+
+						// Do we have an IMEI list?
+						if(imei_list_sz != 0 && conns[i-1]->len > 25){
+							// If so, check IMEI against list
+							if(memmem(imei_list, imei_list_sz, (conns[i-1]->buff + 10), 15) == NULL){
+								if(daemonize){
+									syslog(LOG_NOTICE, "IMEI rejected: %.*s",
+										15, (conns[i-1]->buff + 10)
+									);
+								} else {
+									fprintf(stderr, "%s: IMEI rejected: %.*s\n",
+										exec_name, 15, (conns[i-1]->buff + 10)
+									);
 								}
+								ok = 0;
+							}
+						}
+
+						if(ok) write_connection(conns[i - 1], strip);
 					}
 
 					free(conns[i - 1]);
@@ -444,7 +489,7 @@ int main(int argc, char* argv[])
 }
 
 
-static int write_connection(struct connection *conn)
+static int write_connection(struct connection *conn, int strip)
 {
 	// Build a filename for the file we're writing based
 	// on the time and the source IP address
@@ -473,8 +518,13 @@ static int write_connection(struct connection *conn)
 		return 1;
 	}
 
+
+	unsigned char *buff = (strip ? (conn->buff + 3) : conn->buff);
+	ssize_t len = (strip ? (conn->len - 3) : conn->len);
+
+
 	// Write out the buffer
-	if(write(ofd, conn->buff, conn->len) == -1){
+	if(write(ofd, buff, len) == -1){
 		if(daemonize){
 			syslog(LOG_ERR, "write error on %s - %s",
 				fnbuff, strerror(errno)

src/wstationd.h

@@ -1 +1 @@
-#define VERSION "1.0.1"
+#define VERSION "1.1"