Don't assume sa.sa_family is a short int.

[tinc] / src / subnet_parse.c

diff --git a/src/subnet_parse.c b/src/subnet_parse.c
index 35f078a..611d6bd 100644 (file)
--- a/src/subnet_parse.c
+++ b/src/subnet_parse.c
@@ -27,6 +27,9 @@
 #include "utils.h"
 #include "xalloc.h"
 
+/* Changing this default will affect ADD_SUBNET messages - beware of inconsistencies between versions */
+static const int DEFAULT_WEIGHT = 10;
+
 /* Subnet mask handling */
 
 int maskcmp(const void *va, const void *vb, int masklen) {
@@ -183,9 +186,10 @@ 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 = 10;
+       int weight = DEFAULT_WEIGHT;
        char *weight_separator = strchr(str, '#');
        if (weight_separator) {
                char *weight_str = weight_separator + 1;
@@ -252,17 +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;
@@ -306,46 +311,98 @@ 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, "%hx:%hx:%hx:%hx:%hx:%hx#%d",
+                       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:
-                       snprintf(netstr, len, "%hu.%hu.%hu.%hu/%d#%d",
+                       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],
-                                        subnet->net.ipv4.prefixlength,
-                                        subnet->weight);
+                                        subnet->net.ipv4.address.x[3]);
+                       netstr += result;
+                       len -= result;
+                       prefixlength = subnet->net.ipv4.prefixlength;
+                       if (prefixlength == 32)
+                               prefixlength = -1;
                        break;
 
-               case SUBNET_IPV6:
-                       snprintf(netstr, len, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx/%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: {
+                       /* 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);
        }
 
+       if (prefixlength >= 0) {
+               result = snprintf(netstr, len, "/%d", prefixlength);
+               netstr += result;
+               len -= result;
+       }
+
+       if (subnet->weight != DEFAULT_WEIGHT)
+               snprintf(netstr, len, "#%d", subnet->weight);
+
        return true;
 }