[Feature] Treat v6 mapped addresses as v4 addresses

diff --git a/src/libutil/addr.c b/src/libutil/addr.c
index d02e43985041891f4b4358608dc3e1ddfe5d70ff..992eba9a2de364e5c3acd7591d412420f9bf1df8 100644 (file)
--- a/src/libutil/addr.c
+++ b/src/libutil/addr.c
@@ -568,6 +568,42 @@ rspamd_parse_inet_address_ip6 (const guchar *text, gsize len, gpointer target)
        return FALSE;
 }
 
+/* Checks for ipv6 mapped address */
+static rspamd_inet_addr_t *
+rspamd_inet_address_v6_maybe_map (const struct sockaddr_in6 *sin6)
+{
+       rspamd_inet_addr_t *addr = NULL;
+       /* 10 zero bytes or 80 bits */
+       static const guint8 mask[] = {
+               0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+       };
+       const guint8 *p;
+
+       if (memcmp ((const guint8 *)&sin6->sin6_addr, mask, sizeof (mask)) == 0) {
+               p = (const guint8 *)&sin6->sin6_addr;
+
+               if ((p[11] == 0 && p[12] == 0) ||
+                               (p[11] == 0xff && p[12] == 0xff)) {
+                       addr = rspamd_inet_addr_create (AF_INET);
+                       memcpy (&addr->u.in.addr.s4.sin_addr, &p[13],
+                                       sizeof (struct in_addr));
+               }
+               else {
+                       /* Something strange but not mapped v4 address */
+                       addr = rspamd_inet_addr_create (AF_INET6);
+                       memcpy (&addr->u.in.addr.s6.sin6_addr, &sin6->sin6_addr,
+                                       sizeof (struct in6_addr));
+               }
+       }
+       else {
+               addr = rspamd_inet_addr_create (AF_INET6);
+               memcpy (&addr->u.in.addr.s6.sin6_addr, &sin6->sin6_addr,
+                               sizeof (struct in6_addr));
+       }
+
+       return addr;
+}
+
 gboolean
 rspamd_parse_inet_address (rspamd_inet_addr_t **target,
                const char *src,
@@ -613,9 +649,7 @@ rspamd_parse_inet_address (rspamd_inet_addr_t **target,
                if (ipv6_status == RSPAMD_IPV6_SUPPORTED &&
                                rspamd_parse_inet_address_ip6 (ipbuf, iplen,
                                                &su.s6.sin6_addr)) {
-                       addr = rspamd_inet_addr_create (AF_INET6);
-                       memcpy (&addr->u.in.addr.s6.sin6_addr, &su.s6.sin6_addr,
-                                       sizeof (struct in6_addr));
+                       addr = rspamd_inet_address_v6_maybe_map (&su.s6);
                        ret = TRUE;
                }
 
@@ -633,9 +667,7 @@ rspamd_parse_inet_address (rspamd_inet_addr_t **target,
                        if (memchr (end + 1, ':', srclen - (end - src + 1)) &&
                                        ipv6_status == RSPAMD_IPV6_SUPPORTED &&
                                        rspamd_parse_inet_address_ip6 (src, srclen, &su.s6.sin6_addr)) {
-                               addr = rspamd_inet_addr_create (AF_INET6);
-                               memcpy (&addr->u.in.addr.s6.sin6_addr, &su.s6.sin6_addr,
-                                               sizeof (struct in6_addr));
+                               addr = rspamd_inet_address_v6_maybe_map (&su.s6);
                                ret = TRUE;
                        }
                        else {
@@ -669,9 +701,7 @@ rspamd_parse_inet_address (rspamd_inet_addr_t **target,
                        }
                        else if (ipv6_status == RSPAMD_IPV6_SUPPORTED &&
                                        rspamd_parse_inet_address_ip6 (src, srclen, &su.s6.sin6_addr)) {
-                               addr = rspamd_inet_addr_create (AF_INET6);
-                               memcpy (&addr->u.in.addr.s6.sin6_addr, &su.s6.sin6_addr,
-                                               sizeof (struct in6_addr));
+                               addr = rspamd_inet_address_v6_maybe_map (&su.s6);
                                ret = TRUE;
                        }
                }