s3-talloc Change TALLOC_ZERO_P() to talloc_zero()
[nivanova/samba-autobuild/.git] / source3 / libsmb / unexpected.c
index d123e24aa8ec6cabab9ed3083296e4073d23fffd..cf9ed7dbc6dfdbc9ef1d64bfe12f70fb5cb4098f 100644 (file)
 */
 
 #include "includes.h"
+#include "../lib/util/tevent_ntstatus.h"
+#include "lib/async_req/async_sock.h"
+#include "libsmb/nmblib.h"
 
-static TDB_CONTEXT *tdbd = NULL;
+static const char *nmbd_socket_dir(void)
+{
+       return lp_parm_const_string(-1, "nmbd", "socket dir",
+                                   get_dyn_NMBDSOCKETDIR());
+}
 
-/* the key type used in the unexpected packet database */
-struct unexpected_key {
-       enum packet_type packet_type;
-       time_t timestamp;
-       int count;
+struct nb_packet_query {
+       enum packet_type type;
+       size_t mailslot_namelen;
+       int trn_id;
 };
 
-/****************************************************************************
- All unexpected packets are passed in here, to be stored in a unexpected
- packet database. This allows nmblookup and other tools to receive packets
- erroneously sent to the wrong port by broken MS systems.
-**************************************************************************/
+struct nb_packet_client;
 
-void unexpected_packet(struct packet_struct *p)
-{
-       static int count;
-       TDB_DATA kbuf, dbuf;
-       struct unexpected_key key;
-       char buf[1024];
-       int len=0;
-       uint32_t enc_ip;
-
-       if (!tdbd) {
-               tdbd = tdb_open_log(lock_path("unexpected.tdb"), 0,
-                              TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
-                              O_RDWR | O_CREAT, 0644);
-               if (!tdbd) {
-                       DEBUG(0,("Failed to open unexpected.tdb\n"));
-                       return;
-               }
-       }
+struct nb_packet_server {
+       struct tevent_context *ev;
+       int listen_sock;
+       int max_clients;
+       int num_clients;
+       struct nb_packet_client *clients;
+};
 
-       memset(buf,'\0',sizeof(buf));
+struct nb_packet_client {
+       struct nb_packet_client *prev, *next;
+       struct nb_packet_server *server;
 
-       /* Encode the ip addr and port. */
-       enc_ip = ntohl(p->ip.s_addr);
-       SIVAL(buf,0,enc_ip);
-       SSVAL(buf,4,p->port);
+       enum packet_type type;
+       int trn_id;
+       char *mailslot_name;
 
-       len = build_packet(&buf[6], sizeof(buf)-6, p) + 6;
+       int sock;
+       struct tevent_req *read_req;
+       struct tevent_queue *out_queue;
+};
 
-       ZERO_STRUCT(key);       /* needed for potential alignment */
+static int nb_packet_server_destructor(struct nb_packet_server *s);
+static void nb_packet_server_listener(struct tevent_context *ev,
+                                     struct tevent_fd *fde,
+                                     uint16_t flags,
+                                     void *private_data);
 
-       key.packet_type = p->packet_type;
-       key.timestamp = p->timestamp;
-       key.count = count++;
+NTSTATUS nb_packet_server_create(TALLOC_CTX *mem_ctx,
+                                struct tevent_context *ev,
+                                int max_clients,
+                                struct nb_packet_server **presult)
+{
+       struct nb_packet_server *result;
+       struct tevent_fd *fde;
+       NTSTATUS status;
+
+       result = talloc_zero(mem_ctx, struct nb_packet_server);
+       if (result == NULL) {
+               status = NT_STATUS_NO_MEMORY;
+               goto fail;
+       }
+       result->ev = ev;
+       result->max_clients = max_clients;
+
+       result->listen_sock = create_pipe_sock(
+               nmbd_socket_dir(), "unexpected", 0755);
+       if (result->listen_sock == -1) {
+               status = map_nt_error_from_unix(errno);
+               goto fail;
+       }
+       talloc_set_destructor(result, nb_packet_server_destructor);
 
-       kbuf.dptr = (uint8_t *)&key;
-       kbuf.dsize = sizeof(key);
-       dbuf.dptr = (uint8_t *)buf;
-       dbuf.dsize = len;
+       fde = tevent_add_fd(ev, result, result->listen_sock, TEVENT_FD_READ,
+                           nb_packet_server_listener, result);
+       if (fde == NULL) {
+               status = NT_STATUS_NO_MEMORY;
+               goto fail;
+       }
 
-       tdb_store(tdbd, kbuf, dbuf, TDB_REPLACE);
+       *presult = result;
+       return NT_STATUS_OK;
+fail:
+       TALLOC_FREE(result);
+       return status;
 }
 
+static int nb_packet_server_destructor(struct nb_packet_server *s)
+{
+       if (s->listen_sock != -1) {
+               close(s->listen_sock);
+               s->listen_sock = -1;
+       }
+       return 0;
+}
 
-static time_t lastt;
-
-/****************************************************************************
- Delete the record if it is too old.
-**************************************************************************/
+static int nb_packet_client_destructor(struct nb_packet_client *c);
+static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
+                                    void *private_data);
+static void nb_packet_got_query(struct tevent_req *req);
+static void nb_packet_client_read_done(struct tevent_req *req);
 
-static int traverse_fn(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
+static void nb_packet_server_listener(struct tevent_context *ev,
+                                     struct tevent_fd *fde,
+                                     uint16_t flags,
+                                     void *private_data)
 {
-       struct unexpected_key key;
+       struct nb_packet_server *server = talloc_get_type_abort(
+               private_data, struct nb_packet_server);
+       struct nb_packet_client *client;
+       struct tevent_req *req;
+       struct sockaddr_un sunaddr;
+       socklen_t len;
+       int sock;
+
+       len = sizeof(sunaddr);
+
+       sock = accept(server->listen_sock, (struct sockaddr *)(void *)&sunaddr,
+                     &len);
+       if (sock == -1) {
+               return;
+       }
+       DEBUG(6,("accepted socket %d\n", sock));
+
+       client = talloc_zero(server, struct nb_packet_client);
+       if (client == NULL) {
+               DEBUG(10, ("talloc failed\n"));
+               close(sock);
+               return;
+       }
+       client->sock = sock;
+       client->server = server;
+       talloc_set_destructor(client, nb_packet_client_destructor);
+
+       client->out_queue = tevent_queue_create(
+               client, "unexpected packet output");
+       if (client->out_queue == NULL) {
+               DEBUG(10, ("tevent_queue_create failed\n"));
+               TALLOC_FREE(client);
+               return;
+       }
 
-       if (kbuf.dsize != sizeof(key)) {
-               tdb_delete(ttdb, kbuf);
+       req = read_packet_send(client, ev, client->sock,
+                              sizeof(struct nb_packet_query),
+                              nb_packet_client_more, NULL);
+       if (req == NULL) {
+               DEBUG(10, ("read_packet_send failed\n"));
+               TALLOC_FREE(client);
+               return;
        }
+       tevent_req_set_callback(req, nb_packet_got_query, client);
+
+       DLIST_ADD(server->clients, client);
+       server->num_clients += 1;
 
-       memcpy(&key, kbuf.dptr, sizeof(key));
+       if (server->num_clients > server->max_clients) {
+               DEBUG(10, ("Too many clients, dropping oldest\n"));
+
+               /*
+                * no TALLOC_FREE here, don't mess with the list structs
+                */
+               talloc_free(server->clients->prev);
+       }
+}
 
-       if (lastt - key.timestamp > NMBD_UNEXPECTED_TIMEOUT) {
-               tdb_delete(ttdb, kbuf);
+static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
+                                    void *private_data)
+{
+       struct nb_packet_query q;
+       if (buflen > sizeof(struct nb_packet_query)) {
+               return 0;
+       }
+       /* Take care of alignment */
+       memcpy(&q, buf, sizeof(q));
+       if (q.mailslot_namelen > 1024) {
+               DEBUG(10, ("Got invalid mailslot namelen %d\n",
+                          (int)q.mailslot_namelen));
+               return -1;
        }
+       return q.mailslot_namelen;
+}
 
+static int nb_packet_client_destructor(struct nb_packet_client *c)
+{
+       if (c->sock != -1) {
+               close(c->sock);
+               c->sock = -1;
+       }
+       DLIST_REMOVE(c->server->clients, c);
+       c->server->num_clients -= 1;
        return 0;
 }
 
+static void nb_packet_got_query(struct tevent_req *req)
+{
+       struct nb_packet_client *client = tevent_req_callback_data(
+               req, struct nb_packet_client);
+       struct nb_packet_query q;
+       uint8_t *buf;
+       ssize_t nread, nwritten;
+       int err;
+       char c;
+
+       nread = read_packet_recv(req, talloc_tos(), &buf, &err);
+       TALLOC_FREE(req);
+       if (nread < sizeof(struct nb_packet_query)) {
+               DEBUG(10, ("read_packet_recv returned %d (%s)\n",
+                          (int)nread,
+                          (nread == -1) ? strerror(err) : "wrong length"));
+               TALLOC_FREE(client);
+               return;
+       }
+
+       /* Take care of alignment */
+       memcpy(&q, buf, sizeof(q));
+
+       if (nread != sizeof(struct nb_packet_query) + q.mailslot_namelen) {
+               DEBUG(10, ("nb_packet_got_query: Invalid mailslot namelength\n"));
+               TALLOC_FREE(client);
+               return;
+       }
+
+       client->trn_id = q.trn_id;
+       client->type = q.type;
+       if (q.mailslot_namelen > 0) {
+               client->mailslot_name = talloc_strndup(
+                       client, (char *)buf + sizeof(q),
+                       q.mailslot_namelen);
+               if (client->mailslot_name == NULL) {
+                       TALLOC_FREE(client);
+                       return;
+               }
+       }
+
+       /*
+        * Yes, this is a blocking write of 1 byte into a unix
+        * domain socket that has never been written to. Highly
+        * unlikely that this actually blocks.
+        */
+       c = 0;
+       nwritten = sys_write(client->sock, &c, sizeof(c));
+       if (nwritten != sizeof(c)) {
+               DEBUG(10, ("Could not write success indicator to client: %s\n",
+                          strerror(errno)));
+               TALLOC_FREE(client);
+               return;
+       }
 
-/****************************************************************************
- Delete all old unexpected packets.
-**************************************************************************/
+       client->read_req = read_packet_send(client, client->server->ev,
+                                           client->sock, 1, NULL, NULL);
+       if (client->read_req == NULL) {
+               DEBUG(10, ("Could not activate reader for client exit "
+                          "detection\n"));
+               TALLOC_FREE(client);
+               return;
+       }
+       tevent_req_set_callback(client->read_req, nb_packet_client_read_done,
+                               client);
+}
 
-void clear_unexpected(time_t t)
+static void nb_packet_client_read_done(struct tevent_req *req)
 {
-       if (!tdbd) return;
+       struct nb_packet_client *client = tevent_req_callback_data(
+               req, struct nb_packet_client);
+       ssize_t nread;
+       uint8_t *buf;
+       int err;
+
+       nread = read_packet_recv(req, talloc_tos(), &buf, &err);
+       TALLOC_FREE(req);
+       if (nread == 1) {
+               DEBUG(10, ("Protocol error, received data on write-only "
+                          "unexpected socket: 0x%2.2x\n", (*buf)));
+       }
+       TALLOC_FREE(client);
+}
+
+static void nb_packet_client_send(struct nb_packet_client *client,
+                                 struct packet_struct *p);
 
-       if ((lastt != 0) && (t < lastt + NMBD_UNEXPECTED_TIMEOUT))
+void nb_packet_dispatch(struct nb_packet_server *server,
+                       struct packet_struct *p)
+{
+       struct nb_packet_client *c;
+       uint16_t trn_id;
+
+       switch (p->packet_type) {
+       case NMB_PACKET:
+               trn_id = p->packet.nmb.header.name_trn_id;
+               break;
+       case DGRAM_PACKET:
+               trn_id = p->packet.dgram.header.dgm_id;
+               break;
+       default:
+               DEBUG(10, ("Got invalid packet type %d\n",
+                          (int)p->packet_type));
                return;
+       }
+       for (c = server->clients; c != NULL; c = c->next) {
 
-       lastt = t;
+               if (c->type != p->packet_type) {
+                       DEBUG(10, ("client expects packet %d, got %d\n",
+                                  c->type, p->packet_type));
+                       continue;
+               }
 
-       tdb_traverse(tdbd, traverse_fn, NULL);
+               if (p->packet_type == NMB_PACKET) {
+                       /*
+                        * See if the client specified transaction
+                        * ID. Filter if it did.
+                        */
+                       if ((c->trn_id != -1) &&
+                           (c->trn_id != trn_id)) {
+                               DEBUG(10, ("client expects trn %d, got %d\n",
+                                          c->trn_id, trn_id));
+                               continue;
+                       }
+               } else {
+                       /*
+                        * See if the client specified a mailslot
+                        * name. Filter if it did.
+                        */
+                       if ((c->mailslot_name != NULL) &&
+                           !match_mailslot_name(p, c->mailslot_name)) {
+                               continue;
+                       }
+               }
+               nb_packet_client_send(c, p);
+       }
 }
 
-struct receive_unexpected_state {
-       struct packet_struct *matched_packet;
-       int match_id;
-       enum packet_type match_type;
-       const char *match_name;
+struct nb_packet_client_header {
+       size_t len;
+       enum packet_type type;
+       time_t timestamp;
+       struct in_addr ip;
+       int port;
+};
+
+struct nb_packet_client_state {
+       struct nb_packet_client *client;
+       struct iovec iov[2];
+       struct nb_packet_client_header hdr;
+       char buf[1024];
 };
 
-/****************************************************************************
- tdb traversal fn to find a matching 137 packet.
-**************************************************************************/
+static void nb_packet_client_send_done(struct tevent_req *req);
 
-static int traverse_match(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf,
-                         void *private_data)
+static void nb_packet_client_send(struct nb_packet_client *client,
+                                 struct packet_struct *p)
 {
-       struct receive_unexpected_state *state =
-               (struct receive_unexpected_state *)private_data;
-       struct unexpected_key key;
-       struct in_addr ip;
-       uint32_t enc_ip;
-       int port;
-       struct packet_struct *p;
+       struct nb_packet_client_state *state;
+       struct tevent_req *req;
+
+       if (tevent_queue_length(client->out_queue) > 10) {
+               /*
+                * Skip clients that don't listen anyway, some form of DoS
+                * protection
+                */
+               return;
+       }
 
-       if (kbuf.dsize != sizeof(key)) {
-               return 0;
+       state = talloc_zero(client, struct nb_packet_client_state);
+       if (state == NULL) {
+               DEBUG(10, ("talloc failed\n"));
+               return;
        }
 
-       memcpy(&key, kbuf.dptr, sizeof(key));
+       state->client = client;
 
-       if (key.packet_type != state->match_type) return 0;
+       state->hdr.ip = p->ip;
+       state->hdr.port = p->port;
+       state->hdr.timestamp = p->timestamp;
+       state->hdr.type = p->packet_type;
+       state->hdr.len = build_packet(state->buf, sizeof(state->buf), p);
 
-       if (dbuf.dsize < 6) {
-               return 0;
+       state->iov[0].iov_base = (char *)&state->hdr;
+       state->iov[0].iov_len = sizeof(state->hdr);
+       state->iov[1].iov_base = state->buf;
+       state->iov[1].iov_len = state->hdr.len;
+
+       TALLOC_FREE(client->read_req);
+
+       req = writev_send(client, client->server->ev, client->out_queue,
+                         client->sock, true, state->iov, 2);
+       if (req == NULL) {
+               DEBUG(10, ("writev_send failed\n"));
+               return;
+       }
+       tevent_req_set_callback(req, nb_packet_client_send_done, state);
+}
+
+static void nb_packet_client_send_done(struct tevent_req *req)
+{
+       struct nb_packet_client_state *state = tevent_req_callback_data(
+               req, struct nb_packet_client_state);
+       struct nb_packet_client *client = state->client;
+       ssize_t nwritten;
+       int err;
+
+       nwritten = writev_recv(req, &err);
+
+       TALLOC_FREE(req);
+       TALLOC_FREE(state);
+
+       if (nwritten == -1) {
+               DEBUG(10, ("writev failed: %s\n", strerror(err)));
+               TALLOC_FREE(client);
+       }
+
+       if (tevent_queue_length(client->out_queue) == 0) {
+               client->read_req = read_packet_send(client, client->server->ev,
+                                                   client->sock, 1,
+                                                   NULL, NULL);
+               if (client->read_req == NULL) {
+                       DEBUG(10, ("Could not activate reader for client exit "
+                                  "detection\n"));
+                       TALLOC_FREE(client);
+                       return;
+               }
+               tevent_req_set_callback(client->read_req,
+                                       nb_packet_client_read_done,
+                                       client);
        }
+}
 
-       /* Decode the ip addr and port. */
-       enc_ip = IVAL(dbuf.dptr,0);
-       ip.s_addr = htonl(enc_ip);
-       port = SVAL(dbuf.dptr,4);
+struct nb_packet_reader {
+       int sock;
+};
 
-       p = parse_packet((char *)&dbuf.dptr[6],
-                       dbuf.dsize-6,
-                       state->match_type,
-                       ip,
-                       port);
-       if (!p)
-               return 0;
+struct nb_packet_reader_state {
+       struct tevent_context *ev;
+       struct sockaddr_un addr;
+       struct nb_packet_query query;
+       const char *mailslot_name;
+       struct iovec iov[2];
+       char c;
+       struct nb_packet_reader *reader;
+};
 
-       if ((state->match_type == NMB_PACKET &&
-            p->packet.nmb.header.name_trn_id == state->match_id) ||
-           (state->match_type == DGRAM_PACKET &&
-            match_mailslot_name(p, state->match_name))) {
-               state->matched_packet = p;
-               return -1;
+static int nb_packet_reader_destructor(struct nb_packet_reader *r);
+static void nb_packet_reader_connected(struct tevent_req *subreq);
+static void nb_packet_reader_sent_query(struct tevent_req *subreq);
+static void nb_packet_reader_got_ack(struct tevent_req *subreq);
+
+struct tevent_req *nb_packet_reader_send(TALLOC_CTX *mem_ctx,
+                                        struct tevent_context *ev,
+                                        enum packet_type type,
+                                        int trn_id,
+                                        const char *mailslot_name)
+{
+       struct tevent_req *req, *subreq;
+       struct nb_packet_reader_state *state;
+       char *path;
+
+       req = tevent_req_create(mem_ctx, &state,
+                               struct nb_packet_reader_state);
+       if (req == NULL) {
+               return NULL;
+       }
+       state->ev = ev;
+       state->query.trn_id = trn_id;
+       state->query.type = type;
+       state->mailslot_name = mailslot_name;
+
+       if (mailslot_name != NULL) {
+               state->query.mailslot_namelen = strlen(mailslot_name);
        }
 
-       free_packet(p);
+       state->reader = talloc_zero(state, struct nb_packet_reader);
+       if (tevent_req_nomem(state->reader, req)) {
+               return tevent_req_post(req, ev);
+       }
+
+       path = talloc_asprintf(talloc_tos(), "%s/%s", nmbd_socket_dir(),
+                              "unexpected");
+       if (tevent_req_nomem(path, req)) {
+               return tevent_req_post(req, ev);
+       }
+       state->addr.sun_family = AF_UNIX;
+       strlcpy(state->addr.sun_path, path, sizeof(state->addr.sun_path));
+       TALLOC_FREE(path);
+
+       state->reader->sock = socket(AF_UNIX, SOCK_STREAM, 0);
+       if (state->reader->sock == -1) {
+               tevent_req_nterror(req, map_nt_error_from_unix(errno));
+               return tevent_req_post(req, ev);
+       }
+       talloc_set_destructor(state->reader, nb_packet_reader_destructor);
+
+       subreq = async_connect_send(state, ev, state->reader->sock,
+                                   (struct sockaddr *)(void *)&state->addr,
+                                   sizeof(state->addr));
+       if (tevent_req_nomem(subreq, req)) {
+               return tevent_req_post(req, ev);
+       }
+       tevent_req_set_callback(subreq, nb_packet_reader_connected, req);
+       return req;
+}
 
+static int nb_packet_reader_destructor(struct nb_packet_reader *r)
+{
+       if (r->sock != -1) {
+               close(r->sock);
+               r->sock = -1;
+       }
        return 0;
 }
 
-/****************************************************************************
- Check for a particular packet in the unexpected packet queue.
-**************************************************************************/
+static void nb_packet_reader_connected(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       struct nb_packet_reader_state *state = tevent_req_data(
+               req, struct nb_packet_reader_state);
+       int res, err;
+       int num_iovecs = 1;
+
+       res = async_connect_recv(subreq, &err);
+       TALLOC_FREE(subreq);
+       if (res == -1) {
+               DEBUG(10, ("async_connect failed: %s\n", strerror(err)));
+               tevent_req_nterror(req, map_nt_error_from_unix(err));
+               return;
+       }
+
+       state->iov[0].iov_base = (char *)&state->query;
+       state->iov[0].iov_len = sizeof(state->query);
 
-struct packet_struct *receive_unexpected(enum packet_type packet_type, int id,
-                                        const char *mailslot_name)
+       if (state->mailslot_name != NULL) {
+               num_iovecs = 2;
+               state->iov[1].iov_base = discard_const_p(
+                       char, state->mailslot_name);
+               state->iov[1].iov_len = state->query.mailslot_namelen;
+       }
+
+       subreq = writev_send(state, state->ev, NULL, state->reader->sock,
+                            true, state->iov, num_iovecs);
+       if (tevent_req_nomem(subreq, req)) {
+               return;
+       }
+       tevent_req_set_callback(subreq, nb_packet_reader_sent_query, req);
+}
+
+static void nb_packet_reader_sent_query(struct tevent_req *subreq)
 {
-       TDB_CONTEXT *tdb2;
-       struct receive_unexpected_state state;
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       struct nb_packet_reader_state *state = tevent_req_data(
+               req, struct nb_packet_reader_state);
+       ssize_t written;
+       int err;
+
+       written = writev_recv(subreq, &err);
+       TALLOC_FREE(subreq);
+       if (written == -1) {
+               tevent_req_nterror(req, map_nt_error_from_unix(err));
+               return;
+       }
+       if (written != sizeof(state->query) + state->query.mailslot_namelen) {
+               tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
+               return;
+       }
+       subreq = read_packet_send(state, state->ev, state->reader->sock,
+                                 sizeof(state->c), NULL, NULL);
+       if (tevent_req_nomem(subreq, req)) {
+               return;
+       }
+       tevent_req_set_callback(subreq, nb_packet_reader_got_ack, req);
+}
+
+static void nb_packet_reader_got_ack(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       struct nb_packet_reader_state *state = tevent_req_data(
+               req, struct nb_packet_reader_state);
+       ssize_t nread;
+       int err;
+       uint8_t *buf;
+
+       nread = read_packet_recv(subreq, state, &buf, &err);
+       TALLOC_FREE(subreq);
+       if (nread == -1) {
+               DEBUG(10, ("read_packet_recv returned %s\n",
+                          strerror(err)));
+               tevent_req_nterror(req, map_nt_error_from_unix(err));
+               return;
+       }
+       if (nread != sizeof(state->c)) {
+               DEBUG(10, ("read = %d, expected %d\n", (int)nread,
+                          (int)sizeof(state->c)));
+               tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
+               return;
+       }
+       tevent_req_done(req);
+}
+
+NTSTATUS nb_packet_reader_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
+                              struct nb_packet_reader **preader)
+{
+       struct nb_packet_reader_state *state = tevent_req_data(
+               req, struct nb_packet_reader_state);
+       NTSTATUS status;
+
+       if (tevent_req_is_nterror(req, &status)) {
+               return status;
+       }
+       *preader = talloc_move(mem_ctx, &state->reader);
+       return NT_STATUS_OK;
+}
+
+struct nb_packet_read_state {
+       struct nb_packet_client_header hdr;
+       uint8_t *buf;
+       size_t buflen;
+};
+
+static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p);
+static void nb_packet_read_done(struct tevent_req *subreq);
+
+struct tevent_req *nb_packet_read_send(TALLOC_CTX *mem_ctx,
+                                      struct tevent_context *ev,
+                                      struct nb_packet_reader *reader)
+{
+       struct tevent_req *req, *subreq;
+       struct nb_packet_read_state *state;
+
+       req = tevent_req_create(mem_ctx, &state, struct nb_packet_read_state);
+       if (req == NULL) {
+               return NULL;
+       }
+       subreq = read_packet_send(state, ev, reader->sock,
+                                 sizeof(struct nb_packet_client_header),
+                                 nb_packet_read_more, state);
+       if (tevent_req_nomem(subreq, req)) {
+               return tevent_req_post(req, ev);
+       }
+       tevent_req_set_callback(subreq, nb_packet_read_done, req);
+       return req;
+}
+
+static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p)
+{
+       struct nb_packet_read_state *state = talloc_get_type_abort(
+               p, struct nb_packet_read_state);
 
-       tdb2 = tdb_open_log(lock_path("unexpected.tdb"), 0, 0, O_RDONLY, 0);
-       if (!tdb2) return NULL;
+       if (buflen > sizeof(struct nb_packet_client_header)) {
+               /*
+                * Been here, done
+                */
+               return 0;
+       }
+       memcpy(&state->hdr, buf, sizeof(struct nb_packet_client_header));
+       return state->hdr.len;
+}
 
-       state.matched_packet = NULL;
-       state.match_id = id;
-       state.match_type = packet_type;
-       state.match_name = mailslot_name;
+static void nb_packet_read_done(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       struct nb_packet_read_state *state = tevent_req_data(
+               req, struct nb_packet_read_state);
+       ssize_t nread;
+       int err;
+
+       nread = read_packet_recv(subreq, state, &state->buf, &err);
+       if (nread == -1) {
+               tevent_req_nterror(req, map_nt_error_from_unix(err));
+               return;
+       }
+       state->buflen = nread;
+       tevent_req_done(req);
+}
 
-       tdb_traverse(tdb2, traverse_match, &state);
+NTSTATUS nb_packet_read_recv(struct tevent_req *req,
+                            struct packet_struct **ppacket)
+{
+       struct nb_packet_read_state *state = tevent_req_data(
+               req, struct nb_packet_read_state);
+       struct nb_packet_client_header hdr;
+       struct packet_struct *packet;
+       NTSTATUS status;
+
+       if (tevent_req_is_nterror(req, &status)) {
+               return status;
+       }
 
-       tdb_close(tdb2);
+       memcpy(&hdr, state->buf, sizeof(hdr));
 
-       return state.matched_packet;
+       packet = parse_packet(
+               (char *)state->buf + sizeof(struct nb_packet_client_header),
+               state->buflen - sizeof(struct nb_packet_client_header),
+               state->hdr.type, state->hdr.ip, state->hdr.port);
+       if (packet == NULL) {
+               return NT_STATUS_INVALID_NETWORK_RESPONSE;
+       }
+       *ppacket = packet;
+       return NT_STATUS_OK;
 }