Add proper support for "munging" of ipv6 addresses when ::ffff:addr is used (this...

[user/henk/code/inspircd.git] / include / dns.h

diff --git a/include/dns.h b/include/dns.h
index 7b96f792d97065e923f9308ef610b460d1ef6008..f66d2d3c406410338d7e1b8c5b88bd827fa7acab 100644 (file)
--- a/include/dns.h
+++ b/include/dns.h
@@ -92,10 +92,13 @@ typedef requestlist::iterator requestlist_iter;
  */
 enum QueryType
 {
-       DNS_QUERY_A     = 1,    /* 'A' record: an ipv4 address */
-       DNS_QUERY_CNAME = 5,    /* 'CNAME' record: An alias */
-       DNS_QUERY_PTR   = 12,   /* 'PTR' record: a hostname */
-       DNS_QUERY_AAAA  = 28,    /* 'AAAA' record: an ipv6 address */
+       DNS_QUERY_A     = 1,      /* 'A' record: an ipv4 address */
+       DNS_QUERY_CNAME = 5,      /* 'CNAME' record: An alias */
+       DNS_QUERY_PTR   = 12,     /* 'PTR' record: a hostname */
+       DNS_QUERY_AAAA  = 28,     /* 'AAAA' record: an ipv6 address */
+
+       DNS_QUERY_PTR4  = 0xFFFD, /* Force 'PTR' to use IPV4 scemantics */
+       DNS_QUERY_PTR6  = 0xFFFE, /* Force 'PTR' to use IPV6 scemantics */
 };
 
 #ifdef IPV6
@@ -106,6 +109,16 @@ const QueryType DNS_QUERY_FORWARD = DNS_QUERY_A;
 const QueryType DNS_QUERY_REVERSE = DNS_QUERY_PTR;
 #endif
 
+/**
+ * Used internally to force PTR lookups to use a certain protocol scemantics,
+ * e.g. x.x.x.x.in-addr.arpa for v4, and *.ip6.arpa for v6.
+ */
+enum ForceProtocol
+{
+       PROTOCOL_IPV4 = 0,      /* Forced to use ipv4 */
+       PROTOCOL_IPV6 = 1       /* Forced to use ipv6 */
+};
+
 /**
  * The Resolver class is a high-level abstraction for resolving DNS entries.
  * It can do forward and reverse IPv4 lookups, and where IPv6 is supported, will
@@ -147,14 +160,25 @@ class Resolver : public Extensible
         * the object to go 'out of scope' and cause a segfault in the core if the result
         * arrives at a later time.
         * @param source The IP or hostname to resolve
-        * @param forward Set to true to perform a forward lookup (hostname to ip) or false
-        * to perform a reverse lookup (ip to hostname). Lookups on A records and PTR
-        * records are supported. CNAME and MX are not supported by this resolver.
-        * If InspIRCd is compiled with ipv6 support, lookups on AAAA records are preferred
-        * and supported over A records.
+        * @param qt The query type to perform. If you just want to perform a forward
+        * or reverse lookup, and you don't care wether you get ipv4 or ipv6, then use
+        * the constants DNS_QUERY_FORWARD and DNS_QUERY_REVERSE, which automatically
+        * select from 'A' record or 'AAAA' record lookups. However, if you want to resolve
+        * a specific record type, resolution of 'A', 'AAAA', 'PTR' and 'CNAME' records
+        * is supported. Use one of the QueryType enum values to initiate this type of
+        * lookup. Resolution of 'AAAA' ipv6 records is always supported, regardless of
+        * wether InspIRCd is built with ipv6 support.
+        * If you attempt to resolve a 'PTR' record using DNS_QUERY_PTR, and InspIRCd is
+        * built with ipv6 support, the 'PTR' record will be formatted to ipv6 specs,
+        * e.g. x.x.x.x.x....ip6.arpa. otherwise it will be formatted to ipv4 specs,
+        * e.g. x.x.x.x.in-addr.arpa. This translation is automatic.
+        * To get around this automatic behaviour, you must use one of the values
+        * DNS_QUERY_PTR4 or DNS_QUERY_PTR6 to force ipv4 or ipv6 behaviour on the lookup,
+        * irrespective of what protocol InspIRCd has been built for.
         * @throw ModuleException This class may throw an instance of ModuleException, in the
         * event a lookup could not be allocated, or a similar hard error occurs such as
-        * the network being down.
+        * the network being down. This will also be thrown if an invalid IP address is
+        * passed when resolving a 'PTR' record.
         */
        Resolver(const std::string &source, QueryType qt);
        /**
@@ -224,6 +248,14 @@ class DNS : public Extensible
         */
        Resolver* Classes[MAX_REQUEST_ID];
 
+       /**
+        * We have to turn off a few checks on received packets
+        * when people are using 4in6 (e.g. ::ffff:xxxx). This is
+        * a temporary kludge, Please let me know if you know how
+        * to fix it.
+        */
+       bool ip6munge;
+
        /**
         * Build a dns packet payload
         */
@@ -259,10 +291,20 @@ class DNS : public Extensible
        int GetIP(const char* name);
 
        /**
-        * Start the lookup of a hostname from an ip
+        * Start the lookup of a hostname from an ip,
+        * always using the protocol inspircd is built for,
+        * e.g. use ipv6 reverse lookup when built for ipv6,
+        * or ipv4 lookup when built for ipv4.
         */
        int GetName(const insp_inaddr* ip);
 
+       /**
+        * Start lookup of a hostname from an ip, but
+        * force a specific protocol to be used for the lookup
+        * for example to perform an ipv6 reverse lookup.
+        */
+       int GetNameForce(const char *ip, ForceProtocol fp);
+
        /**
         * Start lookup of an ipv6 from a hostname
         */
@@ -311,6 +353,11 @@ class DNS : public Extensible
         * counter (currid)
         */
        unsigned long PRNG();
+
+       /**
+        * Turn an in6_addr into a .ip6.arpa domain
+        */
+       static void MakeIP6Int(char* query, const in6_addr *ip);
 };
 
 #endif