AAAA support for DNS; from Nick Mathewson.

unfortunately, no regression test



svn:r315

configure.in

@@ -39,7 +39,7 @@ AC_CHECK_LIB(socket, socket)
 
 dnl Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS(fcntl.h stdarg.h inttypes.h stdint.h poll.h signal.h unistd.h sys/epoll.h sys/time.h sys/queue.h sys/event.h sys/ioctl.h sys/devpoll.h port.h)
+AC_CHECK_HEADERS(fcntl.h stdarg.h inttypes.h stdint.h poll.h signal.h unistd.h sys/epoll.h sys/time.h sys/queue.h sys/event.h sys/ioctl.h sys/devpoll.h port.h netinet/in6.h)
 if test "x$ac_cv_header_sys_queue_h" = "xyes"; then
 	AC_MSG_CHECKING(for TAILQ_FOREACH in sys/queue.h)
 	AC_EGREP_CPP(yes,
@@ -340,6 +340,17 @@ AC_CHECK_TYPE(u_int64_t, unsigned long long)
 AC_CHECK_TYPE(u_int32_t, unsigned int)
 AC_CHECK_TYPE(u_int16_t, unsigned short)
 AC_CHECK_TYPE(u_int8_t, unsigned char)
+AC_CHECK_TYPES([struct in6_addr], , ,
+[#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN6_H
+#include <netinet/in6.h>
+#endif])
 
 AC_MSG_CHECKING([for socklen_t])
 AC_TRY_COMPILE([

evdns.c

@@ -105,6 +105,10 @@
 #include <arpa/inet.h>
 #endif
 
+#ifdef HAVE_NETINET_IN6_H
+#include <netinet/in6.h>
+#endif
+
 #define EVDNS_LOG_DEBUG 0
 #define EVDNS_LOG_WARN 1
 
@@ -167,6 +171,12 @@ struct request {
 	char transmit_me;  // needs to be transmitted
 };
 
+#ifndef HAVE_STRUCT_IN6_ADDR
+struct in6_addr {
+	u8 s6_addr[16];
+};
+#endif
+
 struct reply {
 	unsigned int type;
 	unsigned int have_answer;
@@ -175,6 +185,10 @@ struct reply {
 			u32 addrcount;
 			u32 addresses[MAX_ADDRS];
 		} a;
+		struct {
+			u32 addrcount;
+			struct in6_addr addresses[MAX_ADDRS];
+		} aaaa;
 		struct {
 			char name[HOST_NAME_MAX];
 		} ptr;
@@ -574,6 +588,14 @@ reply_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply)
 							   req->user_pointer);
 		}
 		return;
+	case TYPE_AAAA:
+		if (reply)
+			req->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
+							   reply->data.aaaa.addrcount, ttl,
+							   reply->data.aaaa.addresses,
+							   req->user_pointer);
+		else
+			req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
 	}
 	assert(0);
 }
@@ -783,6 +805,24 @@ reply_parse(u8 *packet, int length) {
 				return -1;
 			reply.have_answer = 1;
 			break;
+		} else if (type == TYPE_AAAA && class == CLASS_INET) {
+			int addrcount, addrtocopy;
+			if (req->request_type != TYPE_AAAA) {
+				j += datalength; continue;
+			}
+			// XXXX do something sane with malformed AAAA answers.
+			addrcount = datalength >> 4;  // each address is 16 bytes long
+			addrtocopy = MIN(MAX_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
+			ttl_r = MIN(ttl_r, ttl);
+
+			// we only bother with the first four addresses.
+			if (j + 16*addrtocopy > length) return -1;
+			memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
+				   packet + j, 16*addrtocopy);
+			reply.data.aaaa.addrcount += addrtocopy;
+			j += 16*addrtocopy;
+			reply.have_answer = 1;
+			if (reply.data.aaaa.addrcount == MAX_ADDRS) break;
 		} else {
 			// skip over any other type of resource
 			j += datalength;
@@ -1449,6 +1489,22 @@ int evdns_resolve_ipv4(const char *name, int flags,
 	}
 }
 
+// exported function
+int evdns_resolve_ipv6(const char *name, int flags,
+					   evdns_callback_type callback, void *ptr) {
+	log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
+	if (flags & DNS_QUERY_NO_SEARCH) {
+		struct request *const req =
+			request_new(TYPE_AAAA, name, flags, callback, ptr);
+		if (req == NULL)
+			return (1);
+		request_submit(req);
+		return (0);
+	} else {
+		return (search_request_new(TYPE_AAAA, name, flags, callback, ptr));
+	}
+}
+
 int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	char buf[32];
 	struct request *req;
@@ -1467,6 +1523,29 @@ int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type cal
 	return 0;
 }
 
+int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+	char buf[64];
+	char *cp;
+	struct request *req;
+	int i;
+	assert(in);
+	cp = buf;
+	for (i=15; i >= 0; --i) {
+		u8 byte = in->s6_addr[i];
+		*cp++ = "0123456789abcdef"[byte & 0x0f];
+		*cp++ = '.';
+		*cp++ = "0123456789abcdef"[byte >> 4];
+		*cp++ = '.';
+	}
+	assert(cp + strlen(".ip6.arpa") < buf+sizeof(buf));
+	memcpy(cp, ".ip6.arpa", strlen(".ip6.arpa")+1);
+	log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
+	req = request_new(TYPE_PTR, buf, flags, callback, ptr);
+	if (!req) return 1;
+	request_submit(req);
+	return 0;
+}
+
 /////////////////////////////////////////////////////////////////////
 // Search support
 //

evdns.h

@@ -266,6 +266,7 @@ extern "C" {
 
 #define DNS_IPv4_A 1
 #define DNS_PTR 2
+#define DNS_IPv6_AAAA 3
 
 #define DNS_QUERY_NO_SEARCH 1
 
@@ -276,7 +277,7 @@ extern "C" {
 
 /* 
  * The callback that contains the results from a lookup.
- * - type is either DNS_IPv4_A or DNS_PTR
+ * - type is either DNS_IPv4_A or DNS_PTR or DNS_IPv6_AAAA
  * - count contains the number of addresses of form type
  * - ttl is the number of seconds the resolution may be cached for.
  * - addresses needs to be cast according to type
@@ -292,8 +293,11 @@ int evdns_clear_nameservers_and_suspend(void);
 int evdns_resume(void);
 int evdns_nameserver_ip_add(const char *ip_as_string);
 int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
 struct in_addr;
+struct in6_addr;
 int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
 int evdns_resolv_conf_parse(int flags, const char *);
 #ifdef MS_WINDOWS
 int evdns_config_windows_nameservers(void);