From eda0cc6243c5292fb35fdadf6ec130983c530b2c Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Tue, 27 Jul 2021 12:21:07 +0200 Subject: [PATCH] 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. --- src/subnet_parse.c | 159 +++++---------------------------------------- 1 file changed, 16 insertions(+), 143 deletions(-) diff --git a/src/subnet_parse.c b/src/subnet_parse.c index 312e310c..3273b0b8 100644 --- a/src/subnet_parse.c +++ b/src/subnet_parse.c @@ -213,7 +213,7 @@ int subnet_compare(const subnet_t *a, const subnet_t *b) { /* 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; @@ -278,7 +278,7 @@ 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; } @@ -291,76 +291,10 @@ 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, ':'); - - /* Check that the last colon is not further than possible in an IPv6 address */ - if(last_colon && last_colon >= str + 5 * 8) { - return false; - } - - 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; } @@ -373,10 +307,6 @@ 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; } @@ -394,25 +324,17 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) { switch(subnet->type) { case SUBNET_MAC: - 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]); - netstr += result; - len -= 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]); break; case SUBNET_IPV4: - 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; + inet_ntop(AF_INET, &subnet->net.ipv4.address, netstr, len); prefixlength = subnet->net.ipv4.prefixlength; if(prefixlength == 32) { @@ -422,60 +344,7 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) { break; 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, "%x:", ntohs(subnet->net.ipv6.address.x[i])); - i++; - } - - netstr += result; - len -= result; - } - - /* Remove the trailing colon */ - netstr--; - len++; - *netstr = 0; - + inet_ntop(AF_INET6, &subnet->net.ipv6.address, netstr, len); prefixlength = subnet->net.ipv6.prefixlength; if(prefixlength == 128) { @@ -490,6 +359,10 @@ bool net2str(char *netstr, int len, const subnet_t *subnet) { exit(1); } + size_t used = strlen(netstr); + netstr += used; + len -= used; + if(prefixlength >= 0) { result = snprintf(netstr, len, "/%d", prefixlength); netstr += result; -- 2.20.1