Switch resolver to using resolv_hostent and honor TTL

10 files changed, 401 insertions, 276 deletions

diff --git a/src/providers/data_provider_fo.c b/src/providers/data_provider_fo.c
index f1e1e137..58468c82 100644
--- a/src/providers/data_provider_fo.c
+++ b/src/providers/data_provider_fo.c
@@ -453,14 +453,15 @@ static void be_resolve_server_done(struct tevent_req *subreq)
     /* all fine we got the server */
 
     if (debug_level >= 4) {
-        struct hostent *srvaddr;
+        struct resolv_hostent *srvaddr;
         char ipaddr[128];
         srvaddr = fo_get_server_hostent(state->srv);
-        inet_ntop(srvaddr->h_addrtype, srvaddr->h_addr_list[0],
+        inet_ntop(srvaddr->family, srvaddr->addr_list[0]->ipaddr,
                   ipaddr, 128);
 
-        DEBUG(4, ("Found address for server %s: [%s]\n",
-                  fo_get_server_name(state->srv), ipaddr));
+        DEBUG(4, ("Found address for server %s: [%s] TTL %d\n",
+                  fo_get_server_name(state->srv), ipaddr,
+                  srvaddr->addr_list[0]->ttl));
     }
 
     srv_status_change = fo_get_server_hostname_last_change(state->srv);
diff --git a/src/providers/fail_over.c b/src/providers/fail_over.c
index 3d29779d..c182d80c 100644
--- a/src/providers/fail_over.c
+++ b/src/providers/fail_over.c
@@ -43,10 +43,6 @@
 #define DEFAULT_SERVER_STATUS SERVER_NAME_NOT_RESOLVED
 #define DEFAULT_SRV_STATUS SRV_NEUTRAL
 
-#ifndef HOSTNAME_RESOLVE_TIMEOUT
-#define HOSTNAME_RESOLVE_TIMEOUT 7200
-#endif /* HOSTNAME_RESOLVE_TIMEOUT */
-
 enum srv_lookup_status {
     SRV_NEUTRAL,        /* We didn't try this SRV lookup yet */
     SRV_RESOLVED,       /* This SRV lookup is resolved       */
@@ -94,7 +90,7 @@ struct server_common {
     struct server_common *next;
 
     char *name;
-    struct hostent *hostent;
+    struct resolv_hostent *rhostent;
     struct resolve_service_request *request_list;
     int server_status;
     struct timeval last_status_change;
@@ -328,7 +324,8 @@ get_server_status(struct fo_server *server)
         }
     }
 
-    if (STATUS_DIFF(server->common, tv) > HOSTNAME_RESOLVE_TIMEOUT) {
+    if (server->common->rhostent && STATUS_DIFF(server->common, tv) >
+        server->common->rhostent->addr_list[0]->ttl) {
         DEBUG(4, ("Hostname resolution expired, resetting the server "
                   "status of '%s'\n", SERVER_NAME(server)));
         fo_set_server_status(server, SERVER_NAME_NOT_RESOLVED);
@@ -497,7 +494,7 @@ create_server_common(TALLOC_CTX *mem_ctx, struct fo_ctx *ctx, const char *name)
     common->ctx = ctx;
     common->prev = NULL;
     common->next = NULL;
-    common->hostent = NULL;
+    common->rhostent = NULL;
     common->request_list = NULL;
     common->server_status = DEFAULT_SERVER_STATUS;
     common->last_status_change.tv_sec = 0;
@@ -846,7 +843,8 @@ fo_resolve_service_server(struct tevent_req *req)
         subreq = resolv_gethostbyname_send(state->server->common,
                                            state->ev, state->resolv,
                                            state->server->common->name,
-                                           state->fo_ctx->opts->family_order);
+                                           state->fo_ctx->opts->family_order,
+                                           default_host_dbs);
         if (subreq == NULL) {
             tevent_req_error(req, ENOMEM);
             return true;
@@ -883,13 +881,13 @@ fo_resolve_service_done(struct tevent_req *subreq)
     struct resolve_service_request *request;
     int ret;
 
-    if (state->server->common->hostent != NULL) {
-        talloc_zfree(state->server->common->hostent);
+    if (state->server->common->rhostent != NULL) {
+        talloc_zfree(state->server->common->rhostent);
     }
 
     ret = resolv_gethostbyname_recv(subreq, state->server->common,
                                     &resolv_status, NULL,
-                                    &state->server->common->hostent);
+                                    &state->server->common->rhostent);
     talloc_zfree(subreq);
     if (ret != EOK) {
         DEBUG(1, ("Failed to resolve server '%s': %s\n",
@@ -1224,7 +1222,8 @@ resolve_get_domain_send(TALLOC_CTX *mem_ctx,
 
     subreq = resolv_gethostbyname_send(state, ev, resolv,
                                        state->hostname,
-                                       foctx->opts->family_order);
+                                       foctx->opts->family_order,
+                                       default_host_dbs);
     if (!subreq) {
         talloc_zfree(req);
         return NULL;
@@ -1240,10 +1239,10 @@ static void resolve_get_domain_done(struct tevent_req *subreq)
                                                       struct tevent_req);
     struct resolve_get_domain_state *state = tevent_req_data(req,
                                                       struct resolve_get_domain_state);
-    struct hostent *hostent;
+    struct resolv_hostent *rhostent;
     int ret;
 
-    ret = resolv_gethostbyname_recv(subreq, req, NULL, NULL, &hostent);
+    ret = resolv_gethostbyname_recv(subreq, req, NULL, NULL, &rhostent);
     talloc_zfree(subreq);
     if (ret) {
         DEBUG(2, ("Could not get fully qualified name for host name %s "
@@ -1251,8 +1250,8 @@ static void resolve_get_domain_done(struct tevent_req *subreq)
                   state->hostname, ret, strerror(ret)));
         /* We'll proceed with hostname in this case */
     } else {
-        DEBUG(7, ("The full FQDN is: %s\n", hostent->h_name));
-        state->fqdn = hostent->h_name;
+        DEBUG(7, ("The full FQDN is: %s\n", rhostent->name));
+        state->fqdn = rhostent->name;
     }
     tevent_req_done(req);
 }
@@ -1388,14 +1387,15 @@ const char *fo_get_server_name(struct fo_server *server)
     return server->common->name;
 }
 
-struct hostent *
+struct resolv_hostent *
 fo_get_server_hostent(struct fo_server *server)
 {
     if (server->common == NULL) {
         DEBUG(1, ("Bug: Trying to get hostent from a name-less server\n"));
         return NULL;
     }
-    return server->common->hostent;
+
+    return server->common->rhostent;
 }
 
 time_t
diff --git a/src/providers/fail_over.h b/src/providers/fail_over.h
index 54141e9c..e5d6c525 100644
--- a/src/providers/fail_over.h
+++ b/src/providers/fail_over.h
@@ -169,7 +169,7 @@ int fo_get_server_port(struct fo_server *server);
 
 const char *fo_get_server_name(struct fo_server *server);
 
-struct hostent *fo_get_server_hostent(struct fo_server *server);
+struct resolv_hostent *fo_get_server_hostent(struct fo_server *server);
 
 time_t fo_get_server_hostname_last_change(struct fo_server *server);
 
diff --git a/src/providers/ipa/ipa_common.c b/src/providers/ipa/ipa_common.c
index 6d8a02f2..f4903094 100644
--- a/src/providers/ipa/ipa_common.c
+++ b/src/providers/ipa/ipa_common.c
@@ -592,7 +592,7 @@ static void ipa_resolve_callback(void *private_data, struct fo_server *server)
 {
     TALLOC_CTX *tmp_ctx = NULL;
     struct ipa_service *service;
-    struct hostent *srvaddr;
+    struct resolv_hostent *srvaddr;
     char *address;
     const char *safe_address;
     char *new_uri;
@@ -627,7 +627,7 @@ static void ipa_resolve_callback(void *private_data, struct fo_server *server)
     }
 
     safe_address = sss_ldap_escape_ip_address(tmp_ctx,
-                                              srvaddr->h_addrtype,
+                                              srvaddr->family,
                                               address);
     if (safe_address == NULL) {
         DEBUG(1, ("sss_ldap_escape_ip_address failed.\n"));
diff --git a/src/providers/krb5/krb5_common.c b/src/providers/krb5/krb5_common.c
index c0ed6ce3..b3d8d222 100644
--- a/src/providers/krb5/krb5_common.c
+++ b/src/providers/krb5/krb5_common.c
@@ -377,7 +377,7 @@ done:
 static void krb5_resolve_callback(void *private_data, struct fo_server *server)
 {
     struct krb5_service *krb5_service;
-    struct hostent *srvaddr;
+    struct resolv_hostent *srvaddr;
     char *address;
     int ret;
 
diff --git a/src/providers/ldap/ldap_common.c b/src/providers/ldap/ldap_common.c
index 453e7d76..9796204f 100644
--- a/src/providers/ldap/ldap_common.c
+++ b/src/providers/ldap/ldap_common.c
@@ -533,7 +533,7 @@ static void sdap_uri_callback(void *private_data, struct fo_server *server)
 {
     TALLOC_CTX *tmp_ctx = NULL;
     struct sdap_service *service;
-    struct hostent *srvaddr;
+    struct resolv_hostent *srvaddr;
     char *address;
     const char *safe_address;
     const char *tmp;
@@ -571,7 +571,7 @@ static void sdap_uri_callback(void *private_data, struct fo_server *server)
     }
 
     safe_address = sss_ldap_escape_ip_address(tmp_ctx,
-                                              srvaddr->h_addrtype,
+                                              srvaddr->family,
                                               address);
     talloc_zfree(address);
     if (safe_address == NULL) {
diff --git a/src/resolv/async_resolv.c b/src/resolv/async_resolv.c
index 2f156e3a..c05628a3 100644
--- a/src/resolv/async_resolv.c
+++ b/src/resolv/async_resolv.c
@@ -56,6 +56,8 @@
 #define DNS__16BIT(p)                   (((p)[0] << 8) | (p)[1])
 #define DNS_HEADER_ANCOUNT(h)           DNS__16BIT((h) + 6)
 
+enum host_database default_host_dbs[] = { DB_FILES, DB_DNS, DB_SENTINEL };
+
 struct fd_watch {
     struct fd_watch *prev;
     struct fd_watch *next;
@@ -333,7 +335,8 @@ recreate_ares_channel(struct resolv_ctx *ctx)
     options.sock_state_cb = fd_event;
     options.sock_state_cb_data = ctx;
     options.timeout = ctx->timeout * 1000;
-    options.lookups = discard_const("fb");
+    /* Only affects ares_gethostbyname */
+    options.lookups = discard_const("f");
     options.tries = 1;
     ret = ares_init_options(&new_channel, &options,
                             ARES_OPT_SOCK_STATE_CB |
@@ -401,64 +404,6 @@ resolv_reread_configuration(void)
     }
 }
 
-struct hostent *
-resolv_copy_hostent(TALLOC_CTX *mem_ctx, struct hostent *src)
-{
-    struct hostent *ret;
-    int len;
-    int i;
-
-    ret = talloc_zero(mem_ctx, struct hostent);
-    if (ret == NULL) {
-        return NULL;
-    }
-
-    if (src->h_name != NULL) {
-        ret->h_name = talloc_strdup(ret, src->h_name);
-        if (ret->h_name == NULL) {
-            goto fail;
-        }
-    }
-    if (src->h_aliases != NULL) {
-        for (len = 0; src->h_aliases[len] != NULL; len++);
-        ret->h_aliases = talloc_size(ret, sizeof(char *) * (len + 1));
-        if (ret->h_aliases == NULL) {
-            goto fail;
-        }
-        for (i = 0; i < len; i++) {
-            ret->h_aliases[i] = talloc_strdup(ret->h_aliases, src->h_aliases[i]);
-            if (ret->h_aliases[i] == NULL) {
-                goto fail;
-            }
-        }
-        ret->h_aliases[len] = NULL;
-    }
-    ret->h_addrtype = src->h_addrtype;
-    ret->h_length = src->h_length;
-    if (src->h_addr_list != NULL) {
-        for (len = 0; src->h_addr_list[len] != NULL; len++);
-        ret->h_addr_list = talloc_size(ret, sizeof(char *) * (len + 1));
-        if (ret->h_addr_list == NULL) {
-            goto fail;
-        }
-        for (i = 0; i < len; i++) {
-            ret->h_addr_list[i] = talloc_memdup(ret->h_addr_list,
-                                                src->h_addr_list[i],
-                                                ret->h_length);
-            if (ret->h_addr_list[i] == NULL) {
-                goto fail;
-            }
-        }
-        ret->h_addr_list[len] = NULL;
-    }
-
-    return ret;
-
-fail:
-    talloc_free(ret);
-    return NULL;
-}
-
 static errno_t
 resolv_copy_in_addr(TALLOC_CTX *mem_ctx, struct resolv_addr *ret,
                     struct ares_addrttl *attl)
@@ -529,7 +474,7 @@ fail:
 }
 
 struct resolv_hostent *
-resolv_copy_hostent2(TALLOC_CTX *mem_ctx, struct hostent *src)
+resolv_copy_hostent(TALLOC_CTX *mem_ctx, struct hostent *src)
 {
     struct resolv_hostent *ret;
     int len;
@@ -678,7 +623,7 @@ resolv_gethostbyname_files_send(TALLOC_CTX *mem_ctx,
                                             &hostent);
 
     if (state->status == ARES_SUCCESS) {
-        state->rhostent = resolv_copy_hostent2(state, hostent);
+        state->rhostent = resolv_copy_hostent(state, hostent);
         if (state->rhostent == NULL) {
             tevent_req_error(req, ENOMEM);
             goto done;
@@ -979,30 +924,46 @@ resolv_gethostbyname_dns_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 
 struct gethostbyname_state {
     struct resolv_ctx *resolv_ctx;
+    struct tevent_context *ev;
+
     /* Part of the query. */
     const char *name;
     int family;
+
     /* In which order to use IPv4, or v6 */
     enum restrict_family family_order;
+
+    /* Known hosts databases and index to the current one */
+    enum host_database *db;
+    int dbi;
+
     /* These are returned by ares. The hostent struct will be freed
      * when the user callback returns. */
-    struct hostent *hostent;
+    struct resolv_hostent *rhostent;
     int status;
     int timeouts;
     int retrying;
 };
 
-static void
-ares_gethostbyname_wakeup(struct tevent_req *req);
+static errno_t
+resolv_gethostbyname_address(TALLOC_CTX *mem_ctx, const char *address,
+                             struct resolv_hostent **_rhostent);
+static inline int
+resolv_gethostbyname_family_init(enum restrict_family family_order);
+static bool
+resolv_is_address(const char *name);
+static errno_t
+resolv_gethostbyname_step(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,
-                          enum restrict_family family_order)
+                          enum restrict_family family_order,
+                          enum host_database *db)
 {
-    struct tevent_req *req, *subreq;
+    struct tevent_req *req;
     struct gethostbyname_state *state;
-    struct timeval tv = { 0, 0 };
+    errno_t ret;
 
     if (ctx->channel == NULL) {
         DEBUG(1, ("Invalid ares channel - this is likely a bug\n"));
@@ -1010,141 +971,279 @@ resolv_gethostbyname_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
     }
 
     req = tevent_req_create(mem_ctx, &state, struct gethostbyname_state);
-    if (req == NULL)
+    if (req == NULL) {
         return NULL;
+    }
 
     state->resolv_ctx = ctx;
+    state->ev = ev;
     state->name = name;
-    state->hostent = NULL;
+    state->rhostent = NULL;
     state->status = 0;
     state->timeouts = 0;
     state->retrying = 0;
     state->family_order = family_order;
-    state->family = (family_order < IPV6_ONLY) ? AF_INET : AF_INET6;
+    state->family = resolv_gethostbyname_family_init(state->family_order);
+    state->db = db;
+    state->dbi = 0;
+
+    /* Do not attempt to resolve IP addresses */
+    if (resolv_is_address(state->name)) {
+        ret = resolv_gethostbyname_address(state, state->name,
+                                           &state->rhostent);
+        if (ret != EOK) {
+            DEBUG(1, ("Canot create a fake hostent structure\n"));
+            talloc_zfree(req);
+            return NULL;
+        }
 
-    DEBUG(4, ("Trying to resolve %s record of '%s'\n",
-              state->family == AF_INET ? "A" : "AAAA",
-              state->name));
+        tevent_req_done(req);
+        tevent_req_post(req, ev);
+        return req;
+    }
 
-    /* We need to have a wrapper around ares_gethostbyname(), because
-     * ares_gethostbyname() can in some cases call it's callback immediately.
-     * This would not let our caller to set a callback for req. */
-    subreq = tevent_wakeup_send(req, ev, tv);
-    if (subreq == NULL) {
-        DEBUG(1, ("Failed to add critical timer to run next operation!\n"));
+    ret = resolv_gethostbyname_step(req);
+    if (ret != EOK) {
+        DEBUG(1, ("Cannot start the resolving\n"));
         talloc_zfree(req);
         return NULL;
     }
-    tevent_req_set_callback(subreq, ares_gethostbyname_wakeup, req);
-    schedule_timeout_watcher(ev, ctx);
 
     return req;
 }
 
-static void
-resolv_gethostbyname_next_done(void *arg, int status, int timeouts, struct hostent *hostent);
+static bool
+resolv_is_address(const char *name)
+{
+    struct addrinfo hints;
+    struct addrinfo *res = NULL;
+    int ret;
 
-static void
-resolv_gethostbyname_done(void *arg, int status, int timeouts, struct hostent *hostent)
+    memset((void *) &hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_flags = AI_NUMERICHOST; /* No network lookups */
+
+    ret = getaddrinfo(name, NULL, &hints, &res);
+    freeaddrinfo(res);
+    if (ret != 0) {
+        if (ret == -2) {
+            DEBUG(9, ("[%s] does not look like an IP address\n", name));
+        } else {
+            DEBUG(2, ("getaddrinfo failed [%d]: %s\n",
+                      ret, gai_strerror(ret)));
+        }
+    }
+
+    return ret == 0;
+}
+
+static errno_t
+resolv_gethostbyname_address(TALLOC_CTX *mem_ctx, const char *address,
+                             struct resolv_hostent **_rhostent)
 {
-    struct tevent_req *req = talloc_get_type(arg, struct tevent_req);
-    struct gethostbyname_state *state = tevent_req_data(req, struct gethostbyname_state);
+    struct resolv_hostent *rhostent;
+    TALLOC_CTX *tmp_ctx;
+    errno_t ret;
+    int family;
 
-    if (state->retrying == 0 && status == ARES_EDESTRUCTION
-            && state->resolv_ctx->channel != NULL) {
-        state->retrying = 1;
-        ares_gethostbyname(state->resolv_ctx->channel, state->name,
-                           state->family, resolv_gethostbyname_done, req);
-        return;
+    tmp_ctx = talloc_new(NULL);
+    if (!tmp_ctx) return ENOMEM;
+
+    rhostent = talloc_zero(tmp_ctx, struct resolv_hostent);
+    if (!rhostent) {
+        ret = ENOMEM;
+        goto done;
     }
 
-    unschedule_timeout_watcher(state->resolv_ctx);
+    rhostent->name = talloc_strdup(rhostent, address);
+    rhostent->addr_list = talloc_array(rhostent, struct resolv_addr *, 2);
 
-    if (hostent != NULL) {
-        state->hostent = resolv_copy_hostent(req, hostent);
-        if (state->hostent == NULL) {
-            tevent_req_error(req, ENOMEM);
-            return;
+    if (!rhostent->name ||
+        !rhostent->addr_list) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    rhostent->addr_list[0] = talloc_zero(rhostent->addr_list,
+                                         struct resolv_addr);
+    if (!rhostent->addr_list[0]) {
+        ret = ENOMEM;
+        goto done;
+    }
+    rhostent->addr_list[0]->ipaddr = talloc_array(rhostent->addr_list[0],
+                                                  uint8_t,
+                                                  sizeof(struct in6_addr));
+    if (!rhostent->addr_list[0]->ipaddr) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    family = AF_INET;
+    ret = inet_pton(family, address,
+                    rhostent->addr_list[0]->ipaddr);
+    if (ret != 1) {
+        family = AF_INET6;
+        ret = inet_pton(family, address,
+                        rhostent->addr_list[0]->ipaddr);
+        if (ret != 1) {
+            DEBUG(1, ("Could not parse address as neither v4 nor v6\n"));
+            ret = EINVAL;
+            goto done;
         }
-    } else {
-        state->hostent = NULL;
     }
-    state->status = status;
-    state->timeouts = timeouts;
 
-    if (status != ARES_SUCCESS) {
-        if (status == ARES_ENOTFOUND || status == ARES_ENODATA) {
-            if (state->family_order == IPV4_FIRST) {
-                state->family = AF_INET6;
-            } else if (state->family_order == IPV6_FIRST) {
-                state->family = AF_INET;
-            } else {
-                tevent_req_error(req, return_code(status));
-                return;
-            }
+    rhostent->addr_list[0]->ttl = RESOLV_DEFAULT_TTL;
+    rhostent->addr_list[1] = NULL;
+    rhostent->family = family;
+    rhostent->aliases = NULL;
 
-            state->retrying = 0;
-            state->timeouts = 0;
-            DEBUG(4, ("Trying to resolve %s record of '%s'\n",
-                      state->family == AF_INET ? "A" : "AAAA",
-                      state->name));
-            schedule_timeout_watcher(state->resolv_ctx->ev_ctx,
-                                     state->resolv_ctx);
-            ares_gethostbyname(state->resolv_ctx->channel, state->name,
-                               state->family, resolv_gethostbyname_next_done,
-                               req);
-            return;
+    *_rhostent = talloc_move(mem_ctx, &rhostent);
+    ret = EOK;
+done:
+    talloc_free(tmp_ctx);
+    return ret;
+}
+
+static inline int
+resolv_gethostbyname_family_init(enum restrict_family family_order)
+{
+    switch(family_order) {
+        case IPV4_ONLY:
+        case IPV4_FIRST:
+            return AF_INET;
+        case IPV6_ONLY:
+        case IPV6_FIRST:
+            return AF_INET6;
+    }
+
+    DEBUG(1, ("Unknown address family order %d\n", family_order));
+    return -1;
+}
+
+static int
+resolv_gethostbyname_next(struct gethostbyname_state *state)
+{
+    if (state->family_order == IPV4_FIRST &&
+        state->family == AF_INET) {
+        state->family = AF_INET6;
+        return EOK;
+    } else if (state->family_order == IPV6_FIRST &&
+               state->family == AF_INET6) {
+        state->family = AF_INET;
+        return EOK;
+    } else {
+        /* No more address families for this DB, check if
+         * there is another DB to try */
+        DEBUG(5, ("No more address families to retry\n"));
+        state->dbi++;
+        if (state->db[state->dbi] != DB_SENTINEL) {
+            state->family = resolv_gethostbyname_family_init(
+                                                state->family_order);
+            return EOK;
         }
+    }
 
-        /* Any other error indicates a server error,
-         * so don't bother trying again
-         */
-        tevent_req_error(req, return_code(status));
+    DEBUG(4, ("No more hosts databases to retry\n"));
+    return ENOENT;
+}
+
+static void
+resolv_gethostbyname_done(struct tevent_req *subreq);
+
+static errno_t
+resolv_gethostbyname_step(struct tevent_req *req)
+{
+    struct gethostbyname_state *state = tevent_req_data(req,
+                                                struct gethostbyname_state);
+    struct tevent_req *subreq;
+
+    switch(state->db[state->dbi]) {
+        case DB_FILES:
+            DEBUG(8, ("Querying files\n"));
+            subreq = resolv_gethostbyname_files_send(state, state->ev,
+                                                     state->resolv_ctx,
+                                                     state->name,
+                                                     state->family);
+            break;
+        case DB_DNS:
+            DEBUG(8, ("Querying DNS\n"));
+            subreq = resolv_gethostbyname_dns_send(state, state->ev,
+                                                   state->resolv_ctx,
+                                                   state->name,
+                                                   state->family);
+            break;
+        default:
+            DEBUG(1, ("Invalid hosts database\n"));
+            return EINVAL;
     }
-    else {
-        tevent_req_done(req);
+
+    if (subreq == NULL) {
+        return ENOMEM;
     }
+
+    tevent_req_set_callback(subreq, resolv_gethostbyname_done, req);
+    return EOK;
 }
 
 static void
-resolv_gethostbyname_next_done(void *arg, int status, int timeouts, struct hostent *hostent)
+resolv_gethostbyname_done(struct tevent_req *subreq)
 {
-    struct tevent_req *req = talloc_get_type(arg, struct tevent_req);
-    struct gethostbyname_state *state = tevent_req_data(req, struct gethostbyname_state);
+    struct tevent_req *req = tevent_req_callback_data(subreq,
+                                                      struct tevent_req);
+    struct gethostbyname_state *state = tevent_req_data(req,
+                                                struct gethostbyname_state);
+    errno_t ret;
 
-    if (state->retrying == 0 && status == ARES_EDESTRUCTION) {
-        state->retrying = 1;
-        ares_gethostbyname(state->resolv_ctx->channel, state->name,
-                           state->family, resolv_gethostbyname_next_done, req);
-        return;
+    switch(state->db[state->dbi]) {
+        case DB_FILES:
+            ret = resolv_gethostbyname_files_recv(subreq, state,
+                                                  &state->status,
+                                                  &state->rhostent);
+            /* files is synchronous, there can be no timeouts */
+            state->timeouts = 0;
+            break;
+        case DB_DNS:
+            ret = resolv_gethostbyname_dns_recv(subreq, state,
+                                                &state->status, &state->timeouts,
+                                                &state->rhostent);
+            break;
+        default:
+            DEBUG(1, ("Invalid hosts database\n"));
+            tevent_req_error(req, EINVAL);
+            return;
     }
 
-    unschedule_timeout_watcher(state->resolv_ctx);
+    talloc_zfree(subreq);
 
-    if (hostent != NULL) {
-        state->hostent = resolv_copy_hostent(req, hostent);
-        if (state->hostent == NULL) {
-            tevent_req_error(req, ENOMEM);
+    if (ret == ENOENT) {
+        ret = resolv_gethostbyname_next(state);
+        if (ret == EOK) {
+            ret = resolv_gethostbyname_step(req);
+            if (ret != EOK) {
+                tevent_req_error(req, ret);
+            }
             return;
         }
-    } else {
-        state->hostent = NULL;
-    }
-    state->status = status;
-    state->timeouts = timeouts;
 
-    if (status != ARES_SUCCESS) {
-        tevent_req_error(req, return_code(status));
+        /* No more databases and/or address families */
+        tevent_req_error(req, ENOENT);
+        return;
     }
-    else {
-        tevent_req_done(req);
+
+    if (ret != EOK) {
+        DEBUG(2, ("querying hosts database failed [%d]: %s\n",
+                  ret, strerror(ret)));
+        tevent_req_error(req, ret);
+        return;
     }
+
+    tevent_req_done(req);
 }
 
 int
 resolv_gethostbyname_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
                           int *status, int *timeouts,
-                          struct hostent **hostent)
+                          struct resolv_hostent **rhostent)
 {
     struct gethostbyname_state *state = tevent_req_data(req, struct gethostbyname_state);
 
@@ -1156,8 +1255,8 @@ resolv_gethostbyname_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
     if (timeouts) {
         *timeouts = state->timeouts;
     }
-    if (hostent) {
-        *hostent = talloc_steal(mem_ctx, state->hostent);
+    if (rhostent) {
+        *rhostent = talloc_steal(mem_ctx, state->rhostent);
     }
 
     TEVENT_REQ_RETURN_ON_ERROR(req);
@@ -1166,7 +1265,7 @@ resolv_gethostbyname_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 }
 
 char *
-resolv_get_string_address(TALLOC_CTX *mem_ctx, struct hostent *hostent)
+resolv_get_string_address(TALLOC_CTX *mem_ctx, struct resolv_hostent *hostent)
 {
     char *address;
 
@@ -1179,7 +1278,7 @@ resolv_get_string_address(TALLOC_CTX *mem_ctx, struct hostent *hostent)
     }
 
     errno = 0;
-    if (inet_ntop(hostent->h_addrtype, hostent->h_addr_list[0],
+    if (inet_ntop(hostent->family, hostent->addr_list[0]->ipaddr,
                   address, 128) == NULL) {
         DEBUG(1, ("inet_ntop failed [%d][%s].\n", errno, strerror(errno)));
         talloc_free(address);
@@ -1189,29 +1288,6 @@ resolv_get_string_address(TALLOC_CTX *mem_ctx, struct hostent *hostent)
     return address;
 }
 
-static void
-ares_gethostbyname_wakeup(struct tevent_req *subreq)
-{
-    struct tevent_req *req = tevent_req_callback_data(subreq,
-                                                struct tevent_req);
-    struct gethostbyname_state *state = tevent_req_data(req,
-                                                struct gethostbyname_state);
-
-    if (!tevent_wakeup_recv(subreq)) {
-        return;
-    }
-    talloc_zfree(subreq);
-
-    if (state->resolv_ctx->channel == NULL) {
-        DEBUG(1, ("Invalid ares channel - this is likely a bug\n"));
-        tevent_req_error(req, EIO);
-        return;
-    }
-
-    ares_gethostbyname(state->resolv_ctx->channel, state->name,
-                       state->family, resolv_gethostbyname_done, req);
-}
-
 /*
  * A simple helper function that will take an array of struct ares_srv_reply that
  * was allocated by malloc() in c-ares and copies it using talloc. The old one
diff --git a/src/resolv/async_resolv.h b/src/resolv/async_resolv.h
index 00e1bdfb..907865f7 100644
--- a/src/resolv/async_resolv.h
+++ b/src/resolv/async_resolv.h
@@ -57,6 +57,29 @@ void resolv_reread_configuration(void);
 
 const char *resolv_strerror(int ares_code);
 
+struct resolv_hostent *
+resolv_copy_hostent(TALLOC_CTX *mem_ctx, struct hostent *src);
+
+struct resolv_hostent *
+resolv_copy_hostent_ares(TALLOC_CTX *mem_ctx, struct hostent *src,
+                         int family, void *ares_ttl_data,
+                         int num_ares_ttl_data);
+
+/** Get host by name **/
+enum host_database {
+    DB_FILES,
+    DB_DNS,
+
+    DB_SENTINEL
+};
+
+enum restrict_family {
+    IPV4_ONLY,
+    IPV4_FIRST,
+    IPV6_ONLY,
+    IPV6_FIRST
+};
+
 /* If resolv_hostent->family is AF_INET, then ipaddr points to
  * struct in_addr, else if family is AF_INET6, ipaddr points to
  * struct in6_addr
@@ -74,39 +97,22 @@ struct resolv_hostent {
     struct resolv_addr **addr_list; /* list of addresses */
 };
 
-struct resolv_hostent *
-resolv_copy_hostent2(TALLOC_CTX *mem_ctx, struct hostent *src);
-
-struct resolv_hostent *
-resolv_copy_hostent_ares(TALLOC_CTX *mem_ctx, struct hostent *src,
-                         int family, void *ares_ttl_data,
-                         int num_ares_ttl_data);
-
-struct hostent *resolv_copy_hostent(TALLOC_CTX *mem_ctx,
-                                    struct hostent *src);
-
-/** Get host by name **/
-enum restrict_family {
-    IPV4_ONLY,
-    IPV4_FIRST,
-    IPV6_ONLY,
-    IPV6_FIRST
-};
+/* The default database order */
+extern enum host_database default_host_dbs[];
 
 struct tevent_req *resolv_gethostbyname_send(TALLOC_CTX *mem_ctx,
                                             struct tevent_context *ev,
                                             struct resolv_ctx *ctx,
                                             const char *name,
-                                            enum restrict_family family_order);
+                                            enum restrict_family family_order,
+                                            enum host_database *db);
 
-int resolv_gethostbyname_recv(struct tevent_req *req,
-                              TALLOC_CTX *mem_ctx,
-                              int *status,
-                              int *timeouts,
-                              struct hostent **hostent);
+int resolv_gethostbyname_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
+                              int *status, int *timeouts,
+                              struct resolv_hostent **rhostent);
 
 char *
-resolv_get_string_address(TALLOC_CTX *mem_ctx, struct hostent *hostent);
+resolv_get_string_address(TALLOC_CTX *mem_ctx, struct resolv_hostent *hostent);
 
 /** Get SRV record **/
 struct tevent_req *resolv_getsrv_send(TALLOC_CTX *mem_ctx,
diff --git a/src/tests/fail_over-tests.c b/src/tests/fail_over-tests.c
index a96549dc..84016dd9 100644
--- a/src/tests/fail_over-tests.c
+++ b/src/tests/fail_over-tests.c
@@ -147,7 +147,7 @@ test_resolve_service_callback(struct tevent_req *req)
     int port;
     struct task *task;
     struct fo_server *server = NULL;
-    struct hostent *he;
+    struct resolv_hostent *he;
     int i;
 
     task = tevent_req_callback_data(req, struct task);
@@ -172,10 +172,10 @@ test_resolve_service_callback(struct tevent_req *req)
 
     he = fo_get_server_hostent(server);
     fail_if(he == NULL, "%s: fo_get_server_hostent() returned NULL");
-    for (i = 0; he->h_addr_list[i]; i++) {
+    for (i = 0; he->addr_list[i]; i++) {
         char buf[256];
 
-        inet_ntop(he->h_addrtype, he->h_addr_list[i], buf, sizeof(buf));
+        inet_ntop(he->family, he->addr_list[i]->ipaddr, buf, sizeof(buf));
         fail_if(strcmp(buf, "127.0.0.1") != 0 && strcmp(buf, "::1") != 0);
     }
 
diff --git a/src/tests/resolv-tests.c b/src/tests/resolv-tests.c
index b8c535cf..5c1a487f 100644
--- a/src/tests/resolv-tests.c
+++ b/src/tests/resolv-tests.c
@@ -95,37 +95,59 @@ static int test_loop(struct resolv_test_ctx *data)
 START_TEST(test_copy_hostent)
 {
     void *ctx;
-    struct hostent *new_he;
+    struct resolv_hostent *rhe;
 
     char name[] = "foo.example.com";
     char alias_1[] = "bar.example.com";
     char alias_2[] = "baz.example.com";
     char *aliases[] = { alias_1, alias_2, NULL };
-    char addr_1[] = { 1, 2, 3, 4 };
-    char addr_2[] = { 4, 3, 2, 1 };
-    char *addr_list[] = { addr_1, addr_2, NULL };
+    struct in_addr addr_1 = { 1234 };
+    struct in_addr addr_2 = { 5678 };
+    int ttl_1 = 12;
+    int ttl_2 = 34;
+    char *addr_list[] = { (char *) &addr_2, (char *) &addr_1, NULL };
     struct hostent he = {
-            name, aliases, 123 /* Whatever. */,
+            name, aliases, AF_INET,
             sizeof(addr_1), addr_list
     };
+    struct ares_addrttl attl[] = { { addr_1, ttl_1 }, { addr_2, ttl_2 } };
 
     ctx = talloc_new(global_talloc_context);
     fail_if(ctx == NULL);
 
     check_leaks_push(ctx);
-    new_he = resolv_copy_hostent(ctx, &he);
-    fail_if(new_he == NULL);
-    fail_if(strcmp(new_he->h_name, name));
-    fail_if(strcmp(new_he->h_aliases[0], alias_1));
-    fail_if(strcmp(new_he->h_aliases[1], alias_2));
-    fail_if(new_he->h_aliases[2] != NULL);
-    fail_if(new_he->h_addrtype != 123);
-    fail_if(new_he->h_length != sizeof(addr_1));
-    fail_if(memcmp(new_he->h_addr_list[0], addr_1, sizeof(addr_1)));
-    fail_if(memcmp(new_he->h_addr_list[1], addr_2, sizeof(addr_1)));
-    fail_if(new_he->h_addr_list[2] != NULL);
-
-    talloc_free(new_he);
+
+    rhe = resolv_copy_hostent_ares(ctx, &he, AF_INET, &attl, 2);
+
+    fail_if(rhe == NULL);
+    fail_if(strcmp(rhe->name, name));
+    fail_if(strcmp(rhe->aliases[0], alias_1));
+    fail_if(strcmp(rhe->aliases[1], alias_2));
+    fail_if(rhe->aliases[2] != NULL);
+    fail_if(rhe->family != AF_INET);
+    fail_if(memcmp(rhe->addr_list[0]->ipaddr, &addr_1, sizeof(addr_1)));
+    fail_if(rhe->addr_list[0]->ttl != ttl_1);
+    fail_if(memcmp(rhe->addr_list[1]->ipaddr, &addr_2, sizeof(addr_2)));
+    fail_if(rhe->addr_list[1]->ttl != ttl_2);
+    fail_if(rhe->addr_list[2] != NULL);
+
+    talloc_zfree(rhe);
+
+    rhe = resolv_copy_hostent(ctx, &he);
+    fail_if(rhe == NULL);
+    fail_if(strcmp(rhe->name, name));
+    fail_if(strcmp(rhe->aliases[0], alias_1));
+    fail_if(strcmp(rhe->aliases[1], alias_2));
+    fail_if(rhe->aliases[2] != NULL);
+    fail_if(rhe->family != AF_INET);
+    fail_if(memcmp(rhe->addr_list[0]->ipaddr, &addr_2, sizeof(addr_1)));
+    fail_if(rhe->addr_list[0]->ttl != RESOLV_DEFAULT_TTL);
+    fail_if(memcmp(rhe->addr_list[1]->ipaddr, &addr_1, sizeof(addr_2)));
+    fail_if(rhe->addr_list[1]->ttl != RESOLV_DEFAULT_TTL);
+    fail_if(rhe->addr_list[2] != NULL);
+
+    talloc_free(rhe);
+
     check_leaks_pop(ctx);
 }
 END_TEST
@@ -134,7 +156,7 @@ static void test_ip_addr(struct tevent_req *req)
 {
     int recv_status;
     int status;
-    struct hostent *hostent;
+    struct resolv_hostent *rhostent;
     int i;
     struct resolv_test_ctx *test_ctx = tevent_req_callback_data(req,
                                                                 struct resolv_test_ctx);
@@ -142,7 +164,7 @@ static void test_ip_addr(struct tevent_req *req)
     test_ctx->done = true;
 
     recv_status = resolv_gethostbyname_recv(req, test_ctx,
-                                            &status, NULL, &hostent);
+                                            &status, NULL, &rhostent);
     talloc_zfree(req);
     if (recv_status != EOK) {
         DEBUG(2, ("resolv_gethostbyname_recv failed: %d\n", recv_status));
@@ -152,15 +174,17 @@ static void test_ip_addr(struct tevent_req *req)
     DEBUG(7, ("resolv_gethostbyname_recv status: %d\n", status));
 
     test_ctx->error = ENOENT;
-    for (i = 0; hostent->h_addr_list[i]; i++) {
+    for (i = 0; rhostent->addr_list[i]; i++) {
         char addr_buf[256];
-        inet_ntop(hostent->h_addrtype, hostent->h_addr_list[i], addr_buf, sizeof(addr_buf));
+        inet_ntop(rhostent->family,
+                  rhostent->addr_list[i]->ipaddr,
+                  addr_buf, sizeof(addr_buf));
 
         if (strcmp(addr_buf, "127.0.0.1") == 0) {
             test_ctx->error = EOK;
         }
     }
-    talloc_free(hostent);
+    talloc_free(rhostent);
 }
 
 START_TEST(test_resolv_ip_addr)
@@ -178,7 +202,8 @@ START_TEST(test_resolv_ip_addr)
 
     check_leaks_push(test_ctx);
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_ONLY);
+                                    test_ctx->resolv, hostname, IPV4_ONLY,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -200,7 +225,7 @@ static void test_localhost(struct tevent_req *req)
 {
     int recv_status;
     int status;
-    struct hostent *hostent;
+    struct resolv_hostent *rhostent;
     int i;
     struct resolv_test_ctx *test_ctx = tevent_req_callback_data(req,
                                                                 struct resolv_test_ctx);
@@ -208,7 +233,7 @@ static void test_localhost(struct tevent_req *req)
     test_ctx->done = true;
 
     recv_status = resolv_gethostbyname_recv(req, test_ctx,
-                                            &status, NULL, &hostent);
+                                            &status, NULL, &rhostent);
     talloc_zfree(req);
     if (recv_status != EOK) {
         DEBUG(2, ("resolv_gethostbyname_recv failed: %d\n", recv_status));
@@ -218,16 +243,17 @@ static void test_localhost(struct tevent_req *req)
     DEBUG(7, ("resolv_gethostbyname_recv status: %d\n", status));
 
     test_ctx->error = ENOENT;
-    for (i = 0; hostent->h_addr_list[i]; i++) {
+    for (i = 0; rhostent->addr_list[i]; i++) {
         char addr_buf[256];
-        inet_ntop(hostent->h_addrtype, hostent->h_addr_list[i], addr_buf, sizeof(addr_buf));
+        inet_ntop(rhostent->family, rhostent->addr_list[i]->ipaddr,
+                  addr_buf, sizeof(addr_buf));
 
         /* test that localhost resolves to 127.0.0.1 or ::1 */
         if (strcmp(addr_buf, "127.0.0.1") == 0 || strcmp(addr_buf, "::1") == 0) {
             test_ctx->error = EOK;
         }
     }
-    talloc_free(hostent);
+    talloc_free(rhostent);
 }
 
 START_TEST(test_resolv_localhost)
@@ -245,7 +271,8 @@ START_TEST(test_resolv_localhost)
 
     check_leaks_push(test_ctx);
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_FIRST);
+                                    test_ctx->resolv, hostname, IPV4_FIRST,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -267,7 +294,7 @@ static void test_negative(struct tevent_req *req)
 {
      int recv_status;
      int status;
-     struct hostent *hostent;
+     struct resolv_hostent *hostent;
      struct resolv_test_ctx *test_ctx;
 
      test_ctx = tevent_req_callback_data(req, struct resolv_test_ctx);
@@ -300,7 +327,8 @@ START_TEST(test_resolv_negative)
 
     check_leaks_push(test_ctx);
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_FIRST);
+                                    test_ctx->resolv, hostname, IPV4_FIRST,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -325,9 +353,10 @@ static void test_internet(struct tevent_req *req)
     int status;
     struct resolv_test_ctx *test_ctx;
     void *tmp_ctx;
-    struct hostent *hostent = NULL;
+    struct resolv_hostent *rhostent = NULL;
     struct ares_txt_reply *txt_replies = NULL, *txtptr;
     struct ares_srv_reply *srv_replies = NULL, *srvptr;
+    int i;
 
     test_ctx = tevent_req_callback_data(req, struct resolv_test_ctx);
 
@@ -339,8 +368,18 @@ static void test_internet(struct tevent_req *req)
     switch (test_ctx->tested_function) {
     case TESTING_HOSTNAME:
         recv_status = resolv_gethostbyname_recv(req, tmp_ctx,
-                                                &status, NULL, &hostent);
-        test_ctx->error = (hostent->h_length == 0) ? ENOENT : EOK;
+                                                &status, NULL, &rhostent);
+        test_ctx->error = (rhostent->name == NULL) ? ENOENT : EOK;
+        if (test_ctx->error == EOK) {
+            char addr_buf[256];
+            for (i=0; rhostent->addr_list[i]; i++) {
+                inet_ntop(rhostent->family,
+                          rhostent->addr_list[i]->ipaddr,
+                          addr_buf, sizeof(addr_buf));
+                DEBUG(2, ("Found address %s with TTL %d\n",
+                          addr_buf, rhostent->addr_list[i]->ttl));
+            }
+        }
         break;
     case TESTING_TXT:
         recv_status = resolv_gettxt_recv(tmp_ctx, req, &status, NULL,
@@ -368,8 +407,8 @@ static void test_internet(struct tevent_req *req)
     fail_if(recv_status != EOK, "The recv function failed: %d", recv_status);
     DEBUG(7, ("recv status: %d\n", status));
 
-    if (hostent != NULL) {
-        talloc_free(hostent);
+    if (rhostent != NULL) {
+        talloc_free(rhostent);
     } else if (txt_replies != NULL) {
         talloc_free(txt_replies);
     } else if (srv_replies != NULL) {
@@ -394,7 +433,8 @@ START_TEST(test_resolv_internet)
 
     check_leaks_push(test_ctx);
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_FIRST);
+                                    test_ctx->resolv, hostname, IPV4_FIRST,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         ret = ENOMEM;
@@ -498,7 +538,8 @@ START_TEST(test_resolv_free_context)
     }
 
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_FIRST);
+                                    test_ctx->resolv, hostname, IPV4_FIRST,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         fail("Error calling resolv_gethostbyname_send");
@@ -645,7 +686,8 @@ START_TEST(test_resolv_free_req)
 
     check_leaks_push(test_ctx);
     req = resolv_gethostbyname_send(test_ctx, test_ctx->ev,
-                                    test_ctx->resolv, hostname, IPV4_FIRST);
+                                    test_ctx->resolv, hostname, IPV4_FIRST,
+                                    default_host_dbs);
     DEBUG(7, ("Sent resolv_gethostbyname\n"));
     if (req == NULL) {
         fail("Error calling resolv_gethostbyname_send");