Handle IPv6 addresses with the async resolver

4 files changed, 65 insertions, 13 deletions

diff --git a/server/providers/fail_over.c b/server/providers/fail_over.c
index 9795ccec..7560b89e 100644
--- a/server/providers/fail_over.c
+++ b/server/providers/fail_over.c
@@ -497,9 +497,8 @@ fo_resolve_service_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 
     switch (get_server_status(server)) {
     case SERVER_NAME_NOT_RESOLVED: /* Request name resolution. */
-        /* TODO: Enable IPv6. */
         subreq = resolv_gethostbyname_send(server->common, ev, resolv,
-                                           server->common->name, AF_INET);
+                                           server->common->name);
         if (subreq == NULL) {
             ret = ENOMEM;
             goto done;
diff --git a/server/resolv/async_resolv.c b/server/resolv/async_resolv.c
index 7973a78f..70d8d11e 100644
--- a/server/resolv/async_resolv.c
+++ b/server/resolv/async_resolv.c
@@ -472,7 +472,7 @@ ares_gethostbyname_wakeup(struct tevent_req *req);
 
 struct tevent_req *
 resolv_gethostbyname_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
-                          struct resolv_ctx *ctx, const char *name, int family)
+                          struct resolv_ctx *ctx, const char *name)
 {
     struct tevent_req *req, *subreq;
     struct gethostbyname_state *state;
@@ -491,7 +491,7 @@ resolv_gethostbyname_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 
     state->resolv_ctx = ctx;
     state->name = name;
-    state->family = family;
+    state->family = AF_INET;
     state->hostent = NULL;
     state->status = 0;
     state->timeouts = 0;
@@ -513,6 +513,9 @@ resolv_gethostbyname_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 }
 
 static void
+resolv_gethostbyname6_done(void *arg, int status, int timeouts, struct hostent *hostent);
+
+static void
 resolv_gethostbyname_done(void *arg, int status, int timeouts, struct hostent *hostent)
 {
     struct tevent_req *req = talloc_get_type(arg, struct tevent_req);
@@ -540,10 +543,61 @@ resolv_gethostbyname_done(void *arg, int status, int timeouts, struct hostent *h
     state->status = status;
     state->timeouts = timeouts;
 
-    if (status != ARES_SUCCESS)
+    if (status != ARES_SUCCESS) {
+        if (status == ARES_ENOTFOUND || status == ARES_ENODATA) {
+            /* IPv4 failure. Try IPv6 */
+            state->family = AF_INET6;
+            state->retrying = 0;
+            state->timeouts = 0;
+            DEBUG(4, ("Trying to resolve AAAA record of '%s'\n",
+                      state->name));
+            ares_gethostbyname(state->resolv_ctx->channel, state->name,
+                               state->family, resolv_gethostbyname6_done,
+                               req);
+            return;
+        }
+
+        /* Any other error indicates a server error,
+         * so don't bother trying again
+         */
         tevent_req_error(req, return_code(status));
-    else
+    }
+    else {
         tevent_req_done(req);
+    }
+}
+
+static void
+resolv_gethostbyname6_done(void *arg, int status, int timeouts, struct hostent *hostent)
+{
+    struct tevent_req *req = talloc_get_type(arg, struct tevent_req);
+    struct gethostbyname_state *state = tevent_req_data(req, struct gethostbyname_state);
+
+    if (state->retrying == 0 && status == ARES_EDESTRUCTION) {
+        state->retrying = 1;
+        ares_gethostbyname(state->resolv_ctx->channel, state->name,
+                           state->family, resolv_gethostbyname6_done, req);
+        return;
+    }
+
+    if (hostent != NULL) {
+        state->hostent = resolv_copy_hostent(req, hostent);
+        if (state->hostent == NULL) {
+            tevent_req_error(req, ENOMEM);
+            return;
+        }
+    } else {
+        state->hostent = NULL;
+    }
+    state->status = status;
+    state->timeouts = timeouts;
+
+    if (status != ARES_SUCCESS) {
+        tevent_req_error(req, return_code(status));
+    }
+    else {
+        tevent_req_done(req);
+    }
 }
 
 int
diff --git a/server/resolv/async_resolv.h b/server/resolv/async_resolv.h
index 5558e15c..2ba6449b 100644
--- a/server/resolv/async_resolv.h
+++ b/server/resolv/async_resolv.h
@@ -60,8 +60,7 @@ struct hostent *resolv_copy_hostent(TALLOC_CTX *mem_ctx,
 struct tevent_req *resolv_gethostbyname_send(TALLOC_CTX *mem_ctx,
                                             struct tevent_context *ev,
                                             struct resolv_ctx *ctx,
-                                            const char *name,
-                                            int family);
+                                            const char *name);
 
 int resolv_gethostbyname_recv(struct tevent_req *req,
                               TALLOC_CTX *mem_ctx,
diff --git a/server/tests/resolv-tests.c b/server/tests/resolv-tests.c
index 0c18dfdc..c1b32781 100644
--- a/server/tests/resolv-tests.c
+++ b/server/tests/resolv-tests.c
@@ -178,7 +178,7 @@ START_TEST(test_resolv_localhost)
     }
 
     check_leaks_push(test_ctx);
-    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname, AF_INET);
+    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -232,7 +232,7 @@ START_TEST(test_resolv_negative)
     }
 
     check_leaks_push(test_ctx);
-    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname, AF_INET);
+    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -322,7 +322,7 @@ START_TEST(test_resolv_internet)
     test_ctx->tested_function = TESTING_HOSTNAME;
 
     check_leaks_push(test_ctx);
-    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname, AF_INET);
+    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -425,7 +425,7 @@ START_TEST(test_resolv_free_context)
         return;
     }
 
-    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname, AF_INET);
+    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         fail("Error calling resolv_gethostbyname_send");
@@ -484,7 +484,7 @@ START_TEST(test_resolv_free_req)
     }
 
     check_leaks_push(test_ctx);
-    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname, AF_INET);
+    req = resolv_gethostbyname_send(test_ctx, test_ctx->ev, test_ctx->resolv, hostname);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         fail("Error calling resolv_gethostbyname_send");