added optional choice of bind address (-p) to supernode (ntop#1016)

Author: Logan007

include/n2n_typedefs.h

@@ -659,7 +659,7 @@ typedef struct n2n_edge_conf {
     char                     *encrypt_key;
     int                      register_interval;      /**< Interval for supernode registration, also used for UDP NAT hole punching. */
     int                      register_ttl;           /**< TTL for registration packet when UDP NAT hole punching through supernode. */
-    in_addr_t                bind_address;           /**< The address to bind to if provided (-b) */
+    in_addr_t                bind_address;           /**< The address to bind to if provided */
     n2n_sock_t               preferred_sock;         /**< propagated local sock for better p2p in LAN (-e) */
     uint8_t                  preferred_sock_auto;    /**< indicates desired auto detect for preferred sock */
     int                      local_port;
@@ -813,6 +813,7 @@ typedef struct n2n_sn {
     sn_stats_t                             stats;
     int                                    daemon;          /* If non-zero then daemonise. */
     n2n_mac_t                              mac_addr;
+    in_addr_t                              bind_address;    /* The address to bind to if provided */
     uint16_t                               lport;           /* Local UDP port to bind to. */
     uint16_t                               mport;           /* Management UDP port to bind to. */
     int                                    sock;            /* Main socket for UDP traffic with edges. */

src/sn_utils.c

@@ -745,6 +745,7 @@ int sn_init_defaults (n2n_sn_t *sss) {
     strncpy(sss->version, PACKAGE_VERSION, sizeof(n2n_version_t));
     sss->version[sizeof(n2n_version_t) - 1] = '\0';
     sss->daemon = 1; /* By defult run as a daemon. */
+    sss->bind_address = INADDR_ANY; /* any address */
     sss->lport = N2N_SN_LPORT_DEFAULT;
     sss->mport = N2N_SN_MGMT_PORT;
     sss->sock = -1;

src/supernode.c

@@ -60,7 +60,7 @@ static void help (int level) {
         printf(" general usage:  supernode <config file> (see supernode.conf)\n"
            "\n"
                "            or   supernode "
-               "[-p <local port>] "
+               "[-p [<local bind ip address>:]<local port>] "
             "\n                           "
                "[-F <federation name>] "
             "\n options for under-        "
@@ -113,7 +113,8 @@ static void help (int level) {
         );
         printf (" OPTIONS FOR THE UNDERLYING NETWORK CONNECTION\n");
         printf (" ---------------------------------------------\n\n");
-        printf(" -p <local port>   | fixed local UDP port, defaults to %u\n", N2N_SN_LPORT_DEFAULT);
+        printf(" -p [<ip>:]<port>  | fixed local UDP port (defaults to %u) and optionally\n"
+               "                   | bind to sepcified local IP address only ('any' by default)\n", N2N_SN_LPORT_DEFAULT);
         printf(" -F <fed name>     | name of the supernode's federation, defaults to\n"
                "                   | '%s'\n", (char *)FEDERATION_NAME);
         printf(" -l <host:port>    | ip address or name, and port of known supernode\n");
@@ -167,14 +168,39 @@ static int setOption (int optkey, char *_optarg, n2n_sn_t *sss) {
     //traceEvent(TRACE_NORMAL, "Option %c = %s", optkey, _optarg ? _optarg : "");
 
     switch(optkey) {
-        case 'p': /* local-port */
-            sss->lport = atoi(_optarg);
-
-            if(sss->lport == 0)
-                traceEvent(TRACE_WARNING, "bad local port format, defaulting to %u", N2N_SN_LPORT_DEFAULT);
-                // default is made sure in sn_init()
-
+        case 'p': { /* local-port */
+            char* colon = strpbrk(_optarg, ":");
+            if(colon) { /*ip address:port */
+                *colon = 0;
+                sss->bind_address = ntohl(inet_addr(_optarg));
+                sss->lport = atoi(++colon);
+
+                if(sss->bind_address == INADDR_NONE) {
+                    traceEvent(TRACE_WARNING, "bad address to bind to, binding to any IP address");
+                    sss->bind_address = INADDR_ANY;
+                }
+                if(sss->lport == 0) {
+                    traceEvent(TRACE_WARNING, "bad local port format, defaulting to %u", N2N_SN_LPORT_DEFAULT);
+                    sss->lport = N2N_SN_LPORT_DEFAULT;
+                }
+            } else { /* ip address or port only */
+                char* dot = strpbrk(_optarg, ".");
+                if(dot) { /* ip address only */
+                    sss->bind_address = ntohl(inet_addr(_optarg));
+                    if(sss->bind_address == INADDR_NONE) {
+                        traceEvent(TRACE_WARNING, "bad address to bind to, binding to any IP address");
+                        sss->bind_address = INADDR_ANY;
+                    }
+                } else { /* port only */
+                    sss->lport = atoi(_optarg);
+                    if(sss->lport == 0) {
+                        traceEvent(TRACE_WARNING, "bad local port format, defaulting to %u", N2N_SN_LPORT_DEFAULT);
+                        sss->lport = N2N_SN_LPORT_DEFAULT;
+                    }
+                }
+            }
             break;
+        }
 
         case 't': /* mgmt-port */
             sss->mport = atoi(_optarg);
@@ -603,7 +629,7 @@ int main (int argc, char * const argv[]) {
 
     traceEvent(TRACE_DEBUG, "traceLevel is %d", getTraceLevel());
 
-    sss_node.sock = open_socket(sss_node.lport, INADDR_ANY, 0 /* UDP */);
+    sss_node.sock = open_socket(sss_node.lport, sss_node.bind_address, 0 /* UDP */);
     if(-1 == sss_node.sock) {
         traceEvent(TRACE_ERROR, "failed to open main socket. %s", strerror(errno));
         exit(-2);
@@ -612,7 +638,7 @@ int main (int argc, char * const argv[]) {
     }
 
 #ifdef N2N_HAVE_TCP
-    sss_node.tcp_sock = open_socket(sss_node.lport, INADDR_ANY, 1 /* TCP */);
+    sss_node.tcp_sock = open_socket(sss_node.lport, sss_node.bind_address, 1 /* TCP */);
     if(-1 == sss_node.tcp_sock) {
         traceEvent(TRACE_ERROR, "failed to open auxiliary TCP socket, %s", strerror(errno));
         exit(-2);

supernode.1

@@ -26,8 +26,9 @@ Lines starting with a "#" are ignored.
 An equal sign ('=') should be used between key and value. Example: -p=7777
 .SH OPTIONS FOR THE UNDERLYING NETWORK CONNECTION
 .TP
-\fB\-p \fR<\fIlocal_port\fR>, \fB\-\-local-port\fR=<\fIlocal_port\fR>
-listen on this fixed local UDP port, defaults to 7654
+\fB\-p \fR[<\fIlocal_ip_address\fR>:]<\fIlocal_port\fR>, \fB\-\-local-port\fR=...
+binds supernode to this fixed UDP port on 'any' local IP address, defaults to 7654.
+Optionally, the edge can bind to the provided local ip address only.
 .TP
 \fB\-F \fR<\fIfed_name\fR>
 name of the supernode's federation, defaults to '*Federation' (see also N2N_FEDERATION in ENVIRONMENT)