r6209: started added code to support mailslot requests over UDP/138

datagrams. This adds the IDL to parse mailslot packets, plus mailslot
dispatch and listener registration code.

mailslots are used for UDP/138 browse and netlogon packets
(This used to be commit f20e7e5200de736b3451d748ed716be638f93502)

3 files changed, 302 insertions, 6 deletions

diff --git a/source4/libcli/dgram/dgramsocket.c b/source4/libcli/dgram/dgramsocket.c
index 7f179bc3c3..33734258a3 100644
--- a/source4/libcli/dgram/dgramsocket.c
+++ b/source4/libcli/dgram/dgramsocket.c
@@ -33,15 +33,16 @@
 /*
   handle recv events on a nbt dgram socket
 */
-static void dgm_socket_recv(struct nbt_dgram_socket *nbtsock)
+static void dgm_socket_recv(struct nbt_dgram_socket *dgmsock)
 {
-	TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
+	TALLOC_CTX *tmp_ctx = talloc_new(dgmsock);
 	NTSTATUS status;
 	const char *src_addr;
 	int src_port;
 	DATA_BLOB blob;
 	size_t nread;
 	struct nbt_dgram_packet *packet;
+	const char *mailslot_name;
 
 	blob = data_blob_talloc(tmp_ctx, NULL, DGRAM_MAX_PACKET_SIZE);
 	if (blob.data == NULL) {
@@ -49,7 +50,7 @@ static void dgm_socket_recv(struct nbt_dgram_socket *nbtsock)
 		return;
 	}
 
-	status = socket_recvfrom(nbtsock->sock, blob.data, blob.length, &nread, 0,
+	status = socket_recvfrom(dgmsock->sock, blob.data, blob.length, &nread, 0,
 				 &src_addr, &src_port);
 	if (!NT_STATUS_IS_OK(status)) {
 		talloc_free(tmp_ctx);
@@ -77,13 +78,61 @@ static void dgm_socket_recv(struct nbt_dgram_socket *nbtsock)
 		return;
 	}
 
-	NDR_PRINT_DEBUG(nbt_dgram_packet, packet);
+	/* if this is a mailslot message, then see if we can dispatch it to a handler */
+	mailslot_name = dgram_mailslot_name(packet);
+	if (mailslot_name) {
+		struct dgram_mailslot_handler *dgmslot;
+		dgmslot = dgram_mailslot_find(dgmsock, mailslot_name);
+		if (dgmslot) {
+			dgmslot->handler(dgmslot, packet, src_addr, src_port);
+		} else {
+			DEBUG(2,("No mailslot handler for '%s'\n", mailslot_name));
+		}
+	} else {
+		/* dispatch if there is a general handler */
+		if (dgmsock->incoming.handler) {
+			dgmsock->incoming.handler(dgmsock, packet, src_addr, src_port);
+		}
+	}
 
 	talloc_free(tmp_ctx);
 }
 
 
 /*
+  handle send events on a nbt dgram socket
+*/
+static void dgm_socket_send(struct nbt_dgram_socket *dgmsock)
+{
+	struct nbt_dgram_request *req;
+	NTSTATUS status;
+
+	while ((req = dgmsock->send_queue)) {
+		size_t len;
+		
+		len = req->encoded.length;
+		status = socket_sendto(dgmsock->sock, &req->encoded, &len, 0, 
+				       req->dest_addr, req->dest_port);
+		if (NT_STATUS_IS_ERR(status)) {
+			DEBUG(3,("Failed to send datagram of length %u to %s:%d\n",
+				 req->encoded.length, req->dest_addr, req->dest_port));
+			DLIST_REMOVE(dgmsock->send_queue, req);
+			talloc_free(req);
+			continue;
+		}
+
+		if (!NT_STATUS_IS_OK(status)) return;
+
+		DLIST_REMOVE(dgmsock->send_queue, req);
+		talloc_free(req);
+	}
+
+	EVENT_FD_NOT_WRITEABLE(dgmsock->fde);
+	return;
+}
+
+
+/*
   handle fd events on a nbt_dgram_socket
 */
 static void dgm_socket_handler(struct event_context *ev, struct fd_event *fde,
@@ -92,7 +141,7 @@ static void dgm_socket_handler(struct event_context *ev, struct fd_event *fde,
 	struct nbt_dgram_socket *dgmsock = talloc_get_type(private, 
 							   struct nbt_dgram_socket);
 	if (flags & EVENT_FD_WRITE) {
-		/* nothing at the moment */
+		dgm_socket_send(dgmsock);
 	} else if (flags & EVENT_FD_READ) {
 		dgm_socket_recv(dgmsock);
 	}
@@ -128,6 +177,10 @@ struct nbt_dgram_socket *nbt_dgram_socket_init(TALLOC_CTX *mem_ctx,
 	dgmsock->fde = event_add_fd(dgmsock->event_ctx, dgmsock, 
 				    socket_get_fd(dgmsock->sock), 0,
 				    dgm_socket_handler, dgmsock);
+
+	dgmsock->send_queue = NULL;
+	dgmsock->incoming.handler = NULL;
+	dgmsock->mailslot_handlers = NULL;
 	
 	return dgmsock;
 
@@ -138,7 +191,7 @@ failed:
 
 
 /*
-  setup a handler for incoming requests
+  setup a handler for generic incoming requests
 */
 NTSTATUS dgram_set_incoming_handler(struct nbt_dgram_socket *dgmsock,
 				    void (*handler)(struct nbt_dgram_socket *, 
@@ -151,3 +204,37 @@ NTSTATUS dgram_set_incoming_handler(struct nbt_dgram_socket *dgmsock,
 	EVENT_FD_READABLE(dgmsock->fde);
 	return NT_STATUS_OK;
 }
+
+
+/*
+  queue a datagram for send
+*/
+NTSTATUS nbt_dgram_send(struct nbt_dgram_socket *dgmsock,
+			struct nbt_dgram_packet *packet,
+			const char *dest_addr,
+			int dest_port)
+{
+	struct nbt_dgram_request *req;
+	NTSTATUS status = NT_STATUS_NO_MEMORY;
+
+	req = talloc(dgmsock, struct nbt_dgram_request);
+	if (req == NULL) goto failed;
+
+	req->dest_addr = talloc_strdup(req, dest_addr);
+	if (req->dest_addr == NULL) goto failed;
+	req->dest_port = dest_port;
+
+	status = ndr_push_struct_blob(&req->encoded, req, packet, 
+				      (ndr_push_flags_fn_t)ndr_push_nbt_dgram_packet);
+	if (!NT_STATUS_IS_OK(status)) goto failed;
+
+	DLIST_ADD_END(dgmsock->send_queue, req, struct nbt_dgram_request *);
+
+	EVENT_FD_WRITEABLE(dgmsock->fde);
+
+	return NT_STATUS_OK;
+
+failed:
+	talloc_free(req);
+	return status;
+}
diff --git a/source4/libcli/dgram/libdgram.h b/source4/libcli/dgram/libdgram.h
index 6ead6dccf0..866877e341 100644
--- a/source4/libcli/dgram/libdgram.h
+++ b/source4/libcli/dgram/libdgram.h
@@ -22,6 +22,21 @@
 
 #include "librpc/gen_ndr/ndr_nbt.h"
 
+
+/*
+  a nbt name request
+*/
+struct nbt_dgram_request {
+	struct nbt_dgram_request *next, *prev;
+
+	/* where to send the request */
+	const char *dest_addr;
+	int dest_port;
+
+	/* the encoded request */
+	DATA_BLOB encoded;
+};
+
 /*
   context structure for operations on dgram packets
 */
@@ -32,6 +47,12 @@ struct nbt_dgram_socket {
 	/* the fd event */
 	struct fd_event *fde;
 
+	/* a queue of outgoing requests */
+	struct nbt_dgram_request *send_queue;
+
+	/* a list of mailslot handlers */
+	struct dgram_mailslot_handler *mailslot_handlers;
+
 	/* what to do with incoming request packets */
 	struct {
 		void (*handler)(struct nbt_dgram_socket *, struct nbt_dgram_packet *, 
@@ -39,3 +60,59 @@ struct nbt_dgram_socket {
 		void *private;
 	} incoming;
 };
+
+
+/*
+  the mailslot code keeps a list of mailslot handlers. A mailslot
+  handler is a function that receives incoming packets for a specific
+  mailslot name. When a caller needs to send a mailslot and wants to
+  get a reply then it needs to register itself as listening for
+  incoming packets on the reply mailslot
+*/
+
+typedef void (*dgram_mailslot_handler_t)(struct dgram_mailslot_handler *, 
+					 struct nbt_dgram_packet *, 
+					 const char *, int );
+
+struct dgram_mailslot_handler {
+	struct dgram_mailslot_handler *next, *prev;
+
+	struct nbt_dgram_socket *dgmsock;
+	const char *mailslot_name;
+
+	dgram_mailslot_handler_t handler;
+	void *private;
+};
+
+
+/* prototypes */
+NTSTATUS nbt_dgram_send(struct nbt_dgram_socket *dgmsock,
+			struct nbt_dgram_packet *packet,
+			const char *dest_addr,
+			int dest_port);
+NTSTATUS dgram_set_incoming_handler(struct nbt_dgram_socket *dgmsock,
+				    void (*handler)(struct nbt_dgram_socket *, 
+						    struct nbt_dgram_packet *, 
+						    const char *, int ),
+				    void *private);
+struct nbt_dgram_socket *nbt_dgram_socket_init(TALLOC_CTX *mem_ctx, 
+					       struct event_context *event_ctx);
+
+const char *dgram_mailslot_name(struct nbt_dgram_packet *packet);
+struct dgram_mailslot_handler *dgram_mailslot_find(struct nbt_dgram_socket *dgmsock,
+						   const char *mailslot_name);
+struct dgram_mailslot_handler *dgram_mailslot_listen(struct nbt_dgram_socket *dgmsock,
+						     const char *mailslot_name,
+						     dgram_mailslot_handler_t handler,
+						     void *private);
+struct dgram_mailslot_handler *dgram_mailslot_temp(struct nbt_dgram_socket *dgmsock,
+						   const char *mailslot_name,
+						   dgram_mailslot_handler_t handler,
+						   void *private);
+
+
+
+
+
+
+
diff --git a/source4/libcli/dgram/mailslot.c b/source4/libcli/dgram/mailslot.c
new file mode 100644
index 0000000000..da9b6cdd20
--- /dev/null
+++ b/source4/libcli/dgram/mailslot.c
@@ -0,0 +1,132 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   packet handling for mailslot requests
+
+   Copyright (C) Andrew Tridgell 2005
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "lib/events/events.h"
+#include "dlinklist.h"
+#include "libcli/nbt/libnbt.h"
+#include "libcli/dgram/libdgram.h"
+#include "lib/socket/socket.h"
+
+/*
+  destroy a mailslot handler
+*/
+static int dgram_mailslot_destructor(void *ptr)
+{
+	struct dgram_mailslot_handler *dgmslot = 
+		talloc_get_type(ptr, struct dgram_mailslot_handler);
+	
+	DLIST_REMOVE(dgmslot->dgmsock->mailslot_handlers, dgmslot);
+	return 0;
+}
+
+/*
+  start listening on a mailslot. talloc_free() the handle to stop listening
+*/
+struct dgram_mailslot_handler *dgram_mailslot_listen(struct nbt_dgram_socket *dgmsock,
+						     const char *mailslot_name,
+						     dgram_mailslot_handler_t handler,
+						     void *private)
+{
+	struct dgram_mailslot_handler *dgmslot;
+
+	dgmslot = talloc(dgmsock, struct dgram_mailslot_handler);
+	if (dgmslot == NULL) return NULL;
+
+	dgmslot->dgmsock = dgmsock;
+	dgmslot->mailslot_name = talloc_strdup(dgmslot, mailslot_name);
+	if (dgmslot->mailslot_name == NULL) {
+		talloc_free(dgmslot);
+		return NULL;
+	}
+	dgmslot->handler = handler;
+	dgmslot->private = private;
+
+	DLIST_ADD(dgmsock->mailslot_handlers, dgmslot);
+	talloc_set_destructor(dgmslot, dgram_mailslot_destructor);
+
+	return dgmslot;
+}
+
+/*
+  find the handler for a specific mailslot name
+*/
+struct dgram_mailslot_handler *dgram_mailslot_find(struct nbt_dgram_socket *dgmsock,
+						   const char *mailslot_name)
+{
+	struct dgram_mailslot_handler *h;
+	for (h=dgmsock->mailslot_handlers;h;h=h->next) {
+		if (strcasecmp(h->mailslot_name, mailslot_name) == 0) {
+			return h;
+		}
+	}
+	return NULL;
+}
+
+/*
+  check that a datagram packet is a valid mailslot request, and return the 
+  mailslot name if it is, otherwise return NULL
+*/
+const char *dgram_mailslot_name(struct nbt_dgram_packet *packet)
+{
+	if (packet->msg_type != DGRAM_DIRECT_UNIQUE &&
+	    packet->msg_type != DGRAM_DIRECT_GROUP &&
+	    packet->msg_type != DGRAM_BCAST) {
+		return NULL;
+	}
+	if (packet->data.msg.dgram_body_type != DGRAM_SMB) return NULL;
+	if (packet->data.msg.body.smb.smb_command != SMB_TRANSACTION) return NULL;
+	if (packet->data.msg.body.smb.smb_command != SMB_TRANSACTION) return NULL;
+	return packet->data.msg.body.smb.body.trans.mailslot_name;
+}
+
+
+/*
+  create a temporary mailslot handler for a reply mailslot, allocating
+  a new mailslot name using the given base name and a random integer extension
+*/
+struct dgram_mailslot_handler *dgram_mailslot_temp(struct nbt_dgram_socket *dgmsock,
+						   const char *mailslot_name,
+						   dgram_mailslot_handler_t handler,
+						   void *private)
+{
+	char *name;
+	int i;
+	struct dgram_mailslot_handler *dgmslot;
+
+	/* try a 100 times at most */
+	for (i=0;i<100;i++) {
+		name = talloc_asprintf(dgmsock, "%s%u", 
+				       mailslot_name,
+				       generate_random() % UINT16_MAX);
+		if (name == NULL) return NULL;
+		if (dgram_mailslot_find(dgmsock, name)) {
+			talloc_free(name);
+			return NULL;
+		}
+		dgmslot = dgram_mailslot_listen(dgmsock, name, handler, private);
+		talloc_free(name);
+		return dgmslot;
+	}
+	DEBUG(2,("Unable to create temporary mailslot from %s\n", mailslot_name));
+	return NULL;
+}