Ignore bootstrap nodes that use a domain instead of IP address

Domains cause toxcore to do blocking DNS requests which creates noticable lag
and might (??) leak IP addresses when using a proxy

src/bootstrap.c

@@ -77,7 +77,6 @@ static struct DHT_Nodes {
     char keys[MAXNODES][TOX_PUBLIC_KEY_SIZE];
 } Nodes;
 
-
 /* Return true if nodeslist pointed to by fp needs to be updated.
  * This will be the case if the file is empty, has an invalid format,
  * or if the file is older than the given timeout.
@@ -297,6 +296,11 @@ int load_DHT_nodeslist(void)
         memcpy(ipv4_string, ip_start, ip_len);
         ipv4_string[ip_len] = 0;
 
+        /* ignore domains because we don't want toxcore doing DNS requests during bootstrap. */
+        if (!is_ip4_address(ipv4_string)) {
+            continue;
+        }
+
         /* Extract port */
         const char *port_start = strstr(ip_start, PORT_JSON_VALUE);
 

src/misc_tools.c

@@ -26,7 +26,9 @@
 #include <time.h>
 #include <limits.h>
 #include <dirent.h>
+
 #include <sys/stat.h>
+#include <arpa/inet.h>
 
 #include "toxic.h"
 #include "windows.h"
@@ -478,3 +480,10 @@ void set_window_title(ToxWindow *self, const char *title, int len)
 
     snprintf(self->name, sizeof(self->name), "%s", cpy);
 }
+
+/* Return true if address appears to be a valid ipv4 address. */
+bool is_ip4_address(const char *address)
+{
+    struct sockaddr_in s_addr;
+    return inet_pton(AF_INET, address, &(s_addr.sin_addr)) != 0;
+}

src/misc_tools.h

@@ -161,4 +161,7 @@ int check_file_signature(const char *signature, size_t size, FILE *fp);
 /* sets window title in tab bar. */
 void set_window_title(ToxWindow *self, const char *title, int len);
 
+/* Return true if address appears to be a valid ipv4 address. */
+bool is_ip4_address(const char *address);
+
 #endif /* #define MISC_TOOLS_H */