From: Guus Sliepen <guus@tinc-vpn.org>
Date: Tue, 27 Jul 2021 12:46:17 +0000 (+0200)
Subject: Use inet_pton() to parse Subnets.
X-Git-Url: https://git.tinc-vpn.org/git/browse?a=commitdiff_plain;h=f7f7d8b15e12471c95bbd291195e83c5126a0631;p=tinc

Use inet_pton() to parse Subnets.

Nowadays all operating systems tinc runs on should support IPv6, so we
can rely on inet_pton() and inet_ntop() to convert IPv4 and IPv6
addresses. Use this instead of our own parsing code.
---

diff --git a/src/subnet.c b/src/subnet.c
index 154fd804..da69810c 100644
--- a/src/subnet.c
+++ b/src/subnet.c
@@ -205,7 +205,7 @@ void subnet_del(node_t *n, subnet_t *subnet) {
 /* Ascii representation of subnets */
 
 bool str2net(subnet_t *subnet, const char *subnetstr) {
-	char str[1024];
+	char str[64];
 	strncpy(str, subnetstr, sizeof(str));
 	str[sizeof(str) - 1] = 0;
 	int consumed;
@@ -270,7 +270,7 @@ bool str2net(subnet_t *subnet, const char *subnetstr) {
 		return true;
 	}
 
-	if(sscanf(str, "%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !str[consumed]) {
+	if(inet_pton(AF_INET, str, &subnet->net.ipv4.address)) {
 		if(prefixlength == -1) {
 			prefixlength = 32;
 		}
@@ -283,71 +283,10 @@ bool str2net(subnet_t *subnet, const char *subnetstr) {
 		subnet->net.ipv4.prefixlength = prefixlength;
 		subnet->weight = weight;
 
-		for(int i = 0; i < 4; i++) {
-			if(x[i] > 255) {
-				return false;
-			}
-
-			subnet->net.ipv4.address.x[i] = x[i];
-		}
-
 		return true;
 	}
 
-	/* IPv6 */
-
-	char *last_colon = strrchr(str, ':');
-
-	if(last_colon && sscanf(last_colon, ":%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !last_colon[consumed]) {
-		/* Dotted quad suffix notation, convert to standard IPv6 notation */
-		for(int i = 0; i < 4; i++)
-			if(x[i] > 255) {
-				return false;
-			}
-
-		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++)
-			if(*cur != ':') {
-				zero_group_count--;
-
-				while(cur[1] && cur[1] != ':') {
-					cur++;
-				}
-			}
-
-		if(zero_group_count < 1) {
-			return false;
-		}
-
-		/* Split the double colon in the middle to make room for zero groups */
-		double_colon++;
-		memmove(double_colon + (zero_group_count * 2 - 1), double_colon, strlen(double_colon) + 1);
-
-		/* Write zero groups in the resulting gap, overwriting the second colon */
-		for(int i = 0; i < zero_group_count; i++) {
-			memcpy(&double_colon[i * 2], "0:", 2);
-		}
-
-		/* Remove any leading or trailing colons */
-		if(str[0] == ':') {
-			memmove(&str[0], &str[1], strlen(&str[1]) + 1);
-		}
-
-		if(str[strlen(str) - 1] == ':') {
-			str[strlen(str) - 1] = 0;
-		}
-	}
-
-	if(sscanf(str, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx%n",
-	                &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &x[6], &x[7], &consumed) >= 8 && !str[consumed]) {
+	if(inet_pton(AF_INET6, str, &subnet->net.ipv6.address)) {
 		if(prefixlength == -1) {
 			prefixlength = 128;
 		}
@@ -360,10 +299,6 @@ bool str2net(subnet_t *subnet, const char *subnetstr) {
 		subnet->net.ipv6.prefixlength = prefixlength;
 		subnet->weight = weight;
 
-		for(int i = 0; i < 8; i++) {
-			subnet->net.ipv6.address.x[i] = htons(x[i]);
-		}
-
 		return true;
 	}
 
@@ -376,47 +311,58 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) {
 		return false;
 	}
 
+	int result;
+	int prefixlength = -1;
+
 	switch(subnet->type) {
 	case SUBNET_MAC:
-		snprintf(netstr, len, "%x:%x:%x:%x:%x:%x#%d",
+		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]);
 		break;
 
 	case SUBNET_IPV4:
-		snprintf(netstr, len, "%u.%u.%u.%u/%d#%d",
-		         subnet->net.ipv4.address.x[0],
-		         subnet->net.ipv4.address.x[1],
-		         subnet->net.ipv4.address.x[2],
-		         subnet->net.ipv4.address.x[3],
-		         subnet->net.ipv4.prefixlength,
-		         subnet->weight);
+		inet_ntop(AF_INET, &subnet->net.ipv4.address, netstr, len);
+		prefixlength = subnet->net.ipv4.prefixlength;
+
+		if(prefixlength == 32) {
+			prefixlength = -1;
+		}
+
 		break;
 
-	case SUBNET_IPV6:
-		snprintf(netstr, len, "%x:%x:%x:%x:%x:%x:%x:%x/%d#%d",
-		         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]),
-		         subnet->net.ipv6.prefixlength,
-		         subnet->weight);
+	case SUBNET_IPV6: {
+		inet_ntop(AF_INET6, &subnet->net.ipv6.address, netstr, len);
+		prefixlength = subnet->net.ipv6.prefixlength;
+
+		if(prefixlength == 128) {
+			prefixlength = -1;
+		}
+
 		break;
+	}
 
 	default:
-		logger(LOG_ERR,
-		       "net2str() was called with unknown subnet type %d, exiting!",
-		       subnet->type);
-		exit(0);
+		logger(LOG_ERR, "net2str() was called with unknown subnet type %d, exiting!", subnet->type);
+		exit(1);
+	}
+
+	size_t used = strlen(netstr);
+	netstr += used;
+	len -= used;
+
+	if(prefixlength >= 0) {
+		result = snprintf(netstr, len, "/%d", prefixlength);
+		netstr += result;
+		len -= result;
+	}
+
+	if(subnet->weight != 10) {
+		snprintf(netstr, len, "#%d", subnet->weight);
 	}
 
 	return true;