Add an optional parameter to specify the ip address for reverse connections

For security reasons, it can be important to limit which IP addresses a
LibVNCClient-based client should listen for reverse connections. This
commit adds that option.

To preserve binary backwards-compatibility, the field was added to the end
of the rfbclient struct, and the function ListenAtTcpPort retains its
signature (but calls the new ListenAtTcpPortAndAddress).

[jes: shortened the commit subject, added a longer explanation in the
commit body and adjusted style]

Signed-off-by: Luca Stauble <gnekoz@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

1 files changed, 18 insertions, 1 deletions

diff --git a/libvncclient/sockets.c b/libvncclient/sockets.c
index 6c8cec1..be9924a 100644
--- a/libvncclient/sockets.c
+++ b/libvncclient/sockets.c
@@ -480,13 +480,30 @@ FindFreeTcpPort(void)
 int
 ListenAtTcpPort(int port)
 {
+  return ListenAtTcpPortAndAddress(port, NULL);
+}
+
+
+
+/*
+ * ListenAtTcpPortAndAddress starts listening at the given TCP port on
+ * the given IP address
+ */
+
+int
+ListenAtTcpPortAndAddress(int port, const char *address)
+{
   int sock;
   struct sockaddr_in addr;
   int one = 1;
 
   addr.sin_family = AF_INET;
   addr.sin_port = htons(port);
-  addr.sin_addr.s_addr = htonl(INADDR_ANY);
+  if (address) {
+    addr.sin_addr.s_addr = inet_addr(address);
+  } else {
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);
+  }
 
   if (!initSockets())
     return -1;