X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fsubnet_parse.c;h=611d6bd4415a83a2c4e99a921ce6f5c1df46aae8;hp=b6e209baabbc87ad146c42db31ee455007fec047;hb=d4410d0cce40929db9a0ce7042ef962f1867234d;hpb=dec0400714cc6b125f615c224ac37903f44addb9

diff --git a/src/subnet_parse.c b/src/subnet_parse.c
index b6e209ba..611d6bd4 100644
--- a/src/subnet_parse.c
+++ b/src/subnet_parse.c
@@ -186,6 +186,7 @@ int subnet_compare(const subnet_t *a, const subnet_t *b) {
 bool str2net(subnet_t *subnet, const char *subnetstr) {
 	char str[1024];
 	strncpy(str, subnetstr, sizeof(str));
+	str[sizeof str - 1] = 0;
 	int consumed;
 
 	int weight = DEFAULT_WEIGHT;
@@ -255,17 +256,18 @@ bool str2net(subnet_t *subnet, const char *subnetstr) {
 		for (int i = 0; i < 4; i++)
 			if (x[i] > 255)
 				return false;
-		sprintf(last_colon, ":%02hx%02hx:%02hx%02hx", x[0], x[1], x[2], x[3]);
+		snprintf(last_colon, sizeof str - (last_colon - str), ":%02x%02x:%02x%02x", x[0], x[1], x[2], x[3]);
 	}
 
 	char* double_colon = strstr(str, "::");
 	if (double_colon) {
 		/* Figure out how many zero groups we need to expand */
 		int zero_group_count = 8;
-		for (const char* cur = str; *cur; *cur && cur++)
+		for (const char* cur = str; *cur; cur++)
 			if (*cur != ':') {
 				zero_group_count--;
-				for (; *cur && *cur != ':'; cur++);
+				while(cur[1] && cur[1] != ':')
+					cur++;
 			}
 		if (zero_group_count < 1)
 			return false;
@@ -313,48 +315,85 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) {
 	int prefixlength = -1;
 	switch (subnet->type) {
 		case SUBNET_MAC:
-			result = snprintf(netstr, len, "%02hx:%02hx:%02hx:%02hx:%02hx:%02hx",
+			result = snprintf(netstr, len, "%02x:%02x:%02x:%02x:%02x:%02x",
 					 subnet->net.mac.address.x[0],
 					 subnet->net.mac.address.x[1],
 					 subnet->net.mac.address.x[2],
 					 subnet->net.mac.address.x[3],
 					 subnet->net.mac.address.x[4],
-					 subnet->net.mac.address.x[5],
-					 subnet->weight);
+					 subnet->net.mac.address.x[5]);
+			netstr += result;
+			len -= result;
 			break;
 
 		case SUBNET_IPV4:
-			result = snprintf(netstr, len, "%hu.%hu.%hu.%hu",
+			result = snprintf(netstr, len, "%u.%u.%u.%u",
 					 subnet->net.ipv4.address.x[0],
 					 subnet->net.ipv4.address.x[1],
 					 subnet->net.ipv4.address.x[2],
 					 subnet->net.ipv4.address.x[3]);
+			netstr += result;
+			len -= result;
 			prefixlength = subnet->net.ipv4.prefixlength;
 			if (prefixlength == 32)
 				prefixlength = -1;
 			break;
 
-		case SUBNET_IPV6:
-			result = snprintf(netstr, len, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
-					 ntohs(subnet->net.ipv6.address.x[0]),
-					 ntohs(subnet->net.ipv6.address.x[1]),
-					 ntohs(subnet->net.ipv6.address.x[2]),
-					 ntohs(subnet->net.ipv6.address.x[3]),
-					 ntohs(subnet->net.ipv6.address.x[4]),
-					 ntohs(subnet->net.ipv6.address.x[5]),
-					 ntohs(subnet->net.ipv6.address.x[6]),
-					 ntohs(subnet->net.ipv6.address.x[7]));
+		case SUBNET_IPV6: {
+			/* Find the longest sequence of consecutive zeroes */
+			int max_zero_length = 0;
+			int max_zero_length_index = 0;
+			int current_zero_length = 0;
+			int current_zero_length_index = 0;
+			for (int i = 0; i < 8; i++) {
+				if (subnet->net.ipv6.address.x[i] != 0)
+					current_zero_length = 0;
+				else {
+					if (current_zero_length == 0)
+						current_zero_length_index = i;
+					current_zero_length++;
+					if (current_zero_length > max_zero_length) {
+						max_zero_length = current_zero_length;
+						max_zero_length_index = current_zero_length_index;
+					}
+				}
+			}
+
+			/* Print the address */
+			for (int i = 0; i < 8;) {
+				if (max_zero_length > 1 && max_zero_length_index == i) {
+					/* Shorten the representation as per RFC 5952 */
+					const char* const FORMATS[] = { "%.1s", "%.2s", "%.3s" };
+					const char* const* format = &FORMATS[0];
+					if (i == 0)
+						format++;
+					if (i + max_zero_length == 8)
+						format++;
+					result = snprintf(netstr, len, *format, ":::");
+					i += max_zero_length;
+				} else {
+					result = snprintf(netstr, len, "%hx:", ntohs(subnet->net.ipv6.address.x[i]));
+					i++;
+				}
+				netstr += result;
+				len -= result;
+			}
+
+			/* Remove the trailing colon */
+			netstr--;
+			len++;
+			*netstr = 0;
+
 			prefixlength = subnet->net.ipv6.prefixlength;
 			if (prefixlength == 128)
 				prefixlength = -1;
 			break;
+		}
 
 		default:
 			logger(DEBUG_ALWAYS, LOG_ERR, "net2str() was called with unknown subnet type %d, exiting!", subnet->type);
 			exit(1);
 	}
-	netstr += result;
-	len -= result;
 
 	if (prefixlength >= 0) {
 		result = snprintf(netstr, len, "/%d", prefixlength);
@@ -362,11 +401,8 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) {
 		len -= result;
 	}
 
-	if (subnet->weight != DEFAULT_WEIGHT) {
+	if (subnet->weight != DEFAULT_WEIGHT)
 		snprintf(netstr, len, "#%d", subnet->weight);
-		netstr += result;
-		len -= result;
-	}
 
 	return true;
 }