[PATCH] libgpsd_core: handle IPv6 literals in devices' URIs

[Paul Fertser]

When handling URIs for connecting to remote devices, honour RFC3986
rules for parsing IPv6 (or later) literals (enclosed within square
brackets).

Fixes #44.
---
 libgpsd_core.c | 65 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 45 insertions(+), 20 deletions(-)

diff --git a/libgpsd_core.c b/libgpsd_core.c
index 7adbb1793..52bf8e5ae 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -422,6 +422,35 @@ void gpsd_clear(struct gps_device_t *session)
     session->opentime = time(NULL);
 }
 
+static int parse_uri_dest(struct gps_device_t *session, char *s,
+       char **host, char **service)
+/* split s into host and service parts
+ * if service is not specified, *service is assigned to NULL
+ * return: -1 on error, 0 otherwise
+ */
+{
+       if (s[0] != '[') {
+               *host = s;
+               s = strchr(s, ':');
+       } else { /* IPv6 literal */
+               char *cb = strchr(s, ']');
+               if (!cb || (cb[1] && cb[1] != ':')) {
+                       GPSD_LOG(LOG_ERROR, &session->context->errout,
+                               "Malformed URI specified.\n");
+                       return -1;
+               }
+               *cb = '\0';
+               *host = s + 1;
+               s = cb + 1;
+       }
+       if (s && s[0] && s[1]) {
+               *s = '\0';
+               *service = s + 1;
+       } else
+               *service = NULL;
+       return 0;
+}
+
 int gpsd_open(struct gps_device_t *session)
 /* open a device for access to its data *
  * return: the opened file descriptor
@@ -442,21 +471,19 @@ int gpsd_open(struct gps_device_t *session)
        return session->gpsdata.gps_fd;
     /* otherwise, could be an TCP data feed */
     } else if (str_starts_with(session->gpsdata.dev.path, "tcp://")) {
-       char server[GPS_PATH_MAX], *port;
+       char server[GPS_PATH_MAX], *host, *port;
        socket_t dsock;
        (void)strlcpy(server, session->gpsdata.dev.path + 6, sizeof(server));
        INVALIDATE_SOCKET(session->gpsdata.gps_fd);
-       port = strchr(server, ':');
-       if (port == NULL) {
+       if (parse_uri_dest(session, server, &host, &port) == -1 || !port) {
            GPSD_LOG(LOG_ERROR, &session->context->errout,
-                    "Missing colon in TCP feed spec.\n");
+                    "Missing service in TCP feed spec.\n");
            return -1;
        }
-       *port++ = '\0';
        GPSD_LOG(LOG_INF, &session->context->errout,
-                "opening TCP feed at %s, port %s.\n", server,
+                "opening TCP feed at %s, port %s.\n", host,
                 port);
-       if ((dsock = netlib_connectsock(AF_UNSPEC, server, port, "tcp")) < 0) {
+       if ((dsock = netlib_connectsock(AF_UNSPEC, host, port, "tcp")) < 0) {
            GPSD_LOG(LOG_ERROR, &session->context->errout,
                     "TCP device open error %s.\n",
                     netlib_errstr(dsock));
@@ -469,21 +496,19 @@ int gpsd_open(struct gps_device_t *session)
        return session->gpsdata.gps_fd;
     /* or could be UDP */
     } else if (str_starts_with(session->gpsdata.dev.path, "udp://")) {
-       char server[GPS_PATH_MAX], *port;
+       char server[GPS_PATH_MAX], *host, *port;
        socket_t dsock;
        (void)strlcpy(server, session->gpsdata.dev.path + 6, sizeof(server));
        INVALIDATE_SOCKET(session->gpsdata.gps_fd);
-       port = strchr(server, ':');
-       if (port == NULL) {
+       if (parse_uri_dest(session, server, &host, &port) == -1 || !port) {
            GPSD_LOG(LOG_ERROR, &session->context->errout,
-                    "Missing colon in UDP feed spec.\n");
+                    "Missing service in UDP feed spec.\n");
            return -1;
        }
-       *port++ = '\0';
        GPSD_LOG(LOG_INF, &session->context->errout,
-                "opening UDP feed at %s, port %s.\n", server,
+                "opening UDP feed at %s, port %s.\n", host,
                 port);
-       if ((dsock = netlib_connectsock(AF_UNSPEC, server, port, "udp")) < 0) {
+       if ((dsock = netlib_connectsock(AF_UNSPEC, host, port, "udp")) < 0) {
            GPSD_LOG(LOG_ERROR, &session->context->errout,
                     "UDP device open error %s.\n",
                     netlib_errstr(dsock));
@@ -498,18 +523,18 @@ int gpsd_open(struct gps_device_t *session)
 #endif /* NETFEED_ENABLE */
 #ifdef PASSTHROUGH_ENABLE
     if (str_starts_with(session->gpsdata.dev.path, "gpsd://")) {
-       char server[GPS_PATH_MAX], *port;
+       char server[GPS_PATH_MAX], *host, *port;
        socket_t dsock;
        (void)strlcpy(server, session->gpsdata.dev.path + 7, sizeof(server));
        INVALIDATE_SOCKET(session->gpsdata.gps_fd);
-       if ((port = strchr(server, ':')) == NULL) {
+       if (parse_uri_dest(session, server, &host, &port) == -1)
+               return -1;
+       if (!port)
            port = DEFAULT_GPSD_PORT;
-       } else
-           *port++ = '\0';
        GPSD_LOG(LOG_INF, &session->context->errout,
                 "opening remote gpsd feed at %s, port %s.\n",
-                server, port);
-       if ((dsock = netlib_connectsock(AF_UNSPEC, server, port, "tcp")) < 0) {
+                host, port);
+       if ((dsock = netlib_connectsock(AF_UNSPEC, host, port, "tcp")) < 0) {
            GPSD_LOG(LOG_ERROR, &session->context->errout,
                     "remote gpsd device open error %s.\n",
                     netlib_errstr(dsock));
-- 
2.24.1