Added RESOLVEIPV6 config flag + extended comments in source

Signed-off-by: DL6ER <dl6er@dl6er.de>

FTL.h

@@ -120,6 +120,7 @@ typedef struct {
 	bool query_display;
 	bool analyze_AAAA;
 	int maxDBdays;
+	bool resolveIPv6;
 } ConfigStruct;
 
 // Dynamic structs

README.md

@@ -104,6 +104,7 @@ Possible settings (**the option shown first is the default**):
 - `QUERY_DISPLAY=yes|no` (Display all queries? Set to `no` to hide query display)
 - `AAAA_QUERY_ANALYSIS=yes|no` (Allow `FTL` to analyze AAAA queries from pihole.log?)
 - `MAXDBDAYS=365` (How long should queries be stored in the database? Setting this to `0` disables the database altogether)
+- `RESOLVEIPV6=yes|no` (Should `FTL` try to resolve IPv6 addresses to host names?)
 
 ### Implemented keywords (starting with `>`, subject to change):
 

config.c

@@ -111,6 +111,20 @@ void read_FTLconf(void)
 	else
 		logg("   MAXDBDAYS: max age for stored queries is %i days", config.maxDBdays);
 
+	// RESOLVEIPV6
+	// defaults to: Yes
+	config.resolveIPv6 = true;
+	buffer = parse_FTLconf(fp, "RESOLVEIPV6");
+	if(buffer != NULL)
+	{
+		if(strcmp(buffer, "no") == 0)
+			config.resolveIPv6 = false;
+	}
+	if(config.resolveIPv6)
+		logg("   RESOLVEIPV6: Resolve IPv6 addresses");
+	else
+		logg("   RESOLVEIPV6: Don\'t resolve IPv6 addresses");
+
 	logg("Finished config file parsing");
 
 	if(conflinebuffer != NULL)

parser.c

@@ -718,15 +718,23 @@ void process_pihole_log(int file)
 char *resolveHostname(const char *addr)
 {
 	// Get host name
-	struct hostent *he;
+	struct hostent *he = NULL;
 	char *hostname;
+	bool IPv6 = false;
+
+	// Test if we want to resolve an IPv6 address
 	if(strstr(addr,":") != NULL)
+	{
+		IPv6 = true;
+	}
+
+	if(IPv6 && config.resolveIPv6) // Resolve IPv6 address only if requested
 	{
 		struct in6_addr ipaddr;
 		inet_pton(AF_INET6, addr, &ipaddr);
 		he = gethostbyaddr(&ipaddr, sizeof ipaddr, AF_INET6);
 	}
-	else
+	else if(!IPv6) // Always resolve IPv4 addresses
 	{
 		struct in_addr ipaddr;
 		inet_pton(AF_INET, addr, &ipaddr);
@@ -735,11 +743,13 @@ char *resolveHostname(const char *addr)
 
 	if(he == NULL)
 	{
+		// No hostname found
 		hostname = calloc(1,sizeof(char));
 		hostname[0] = '\0';
 	}
 	else
 	{
+		// Return hostname copied to new memory location
 		hostname = strdup(he->h_name);
 	}