r5392: added "secure" WINS server processing. Send a WACK on name

registrations from anyone who isn't a current owner, then query the
owner addresses to see if they still want it.
(This used to be commit 8dc2a028d3ca0115d3173df435d926d7b6a4d5d5)

1 files changed, 199 insertions, 0 deletions

diff --git a/source4/nbt_server/winswack.c b/source4/nbt_server/winswack.c
new file mode 100644
index 0000000000..a15f0a7d06
--- /dev/null
+++ b/source4/nbt_server/winswack.c
@@ -0,0 +1,199 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   "secure" wins server WACK processing
+
+   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 "nbt_server/nbt_server.h"
+#include "nbt_server/winsdb.h"
+#include "system/time.h"
+
+struct wack_state {
+	struct wins_server *winssrv;
+	struct nbt_name_socket *nbtsock;
+	struct nbt_name_packet *request_packet;
+	struct winsdb_record *rec;
+	const char *src_address;
+	int src_port;
+	const char **owner_addresses;
+	const char *reg_address;
+	struct nbt_name_query query;
+};
+
+
+/*
+  deny a registration request
+*/
+static void wins_wack_deny(struct wack_state *state)
+{
+	nbtd_name_registration_reply(state->nbtsock, state->request_packet, 
+				     state->src_address, state->src_port, NBT_RCODE_ACT);
+	DEBUG(4,("WINS: denied name registration request for %s from %s\n",
+		 nbt_name_string(state, state->rec->name), state->src_address));
+	talloc_free(state);
+}
+
+/*
+  allow a registration request
+*/
+static void wins_wack_allow(struct wack_state *state)
+{
+	uint32_t ttl;
+	time_t now = time(NULL);
+	struct winsdb_record *rec = state->rec;
+
+	nbtd_name_registration_reply(state->nbtsock, state->request_packet, 
+				     state->src_address, state->src_port, NBT_RCODE_OK);
+
+	rec->addresses = str_list_add(rec->addresses, state->reg_address);
+	if (rec->addresses == NULL) goto failed;
+	
+	ttl = wins_server_ttl(state->winssrv, state->request_packet->additional[0].ttl);
+	if (now + ttl > rec->expire_time) {
+		rec->expire_time = now + ttl;
+	}
+	rec->registered_by = state->src_address;
+
+	winsdb_modify(state->winssrv, rec);
+
+	DEBUG(4,("WINS: accepted registration of %s with address %s\n",
+		 nbt_name_string(state, rec->name), state->reg_address));
+
+failed:
+	talloc_free(state);
+}
+
+/*
+  called when a name query to a current owner completes
+*/
+static void wins_wack_handler(struct nbt_name_request *req)
+{
+	struct wack_state *state = talloc_get_type(req->async.private, struct wack_state);
+	NTSTATUS status;
+	int i;
+	struct winsdb_record *rec = state->rec;
+
+	status = nbt_name_query_recv(req, state, &state->query);
+
+	/* if we timed out then try the next owner address, if any */
+	if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) {
+		state->owner_addresses++;
+		if (state->owner_addresses[0] == NULL) {
+			wins_wack_allow(state);
+			return;
+		}
+		state->query.in.dest_addr = state->owner_addresses[0];
+
+		req = nbt_name_query_send(state->nbtsock, &state->query);
+		if (req == NULL) goto failed;
+
+		req->async.fn = wins_wack_handler;
+		req->async.private = state;
+		return;
+	}
+
+	/* if the owner denies it holds the name, then allow
+	   the registration */
+	if (!NT_STATUS_IS_OK(status)) {
+		wins_wack_allow(state);
+		return;
+	}
+
+	/* if the owner still wants the name and doesn't reply
+	   with the address trying to be registered, then deny
+	   the registration */
+	if (!str_list_check(state->query.out.reply_addrs, state->reg_address)) {
+		wins_wack_deny(state);
+		return;
+	}
+
+	/* we are going to allow the registration, but first remove any addresses
+	   from the record that aren't in the reply from the client */
+	for (i=0;rec->addresses[i];) {
+		if (!str_list_check(state->query.out.reply_addrs, rec->addresses[i])) {
+			str_list_remove(rec->addresses, rec->addresses[i]);
+		} else {
+			i++;
+		}
+	}
+
+	wins_wack_allow(state);
+	return;
+
+failed:
+	talloc_free(state);
+}
+
+
+/*
+  a client has asked to register a unique name that someone else owns. We
+  need to ask each of the current owners if they still want it. If they do
+  then reject the registration, otherwise allow it
+*/
+void wins_register_wack(struct nbt_name_socket *nbtsock, 
+			struct nbt_name_packet *packet, 
+			struct winsdb_record *rec,
+			const char *src_address, int src_port)
+{
+	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
+						       struct nbtd_interface);
+	struct wins_server *winssrv = iface->nbtsrv->winssrv;
+	struct wack_state *state;
+	struct nbt_name_request *req;
+	uint32_t ttl;
+
+	state = talloc(nbtsock, struct wack_state);
+	if (state == NULL) goto failed;
+
+	/* package up the state variables for this wack request */
+	state->winssrv         = winssrv;
+	state->nbtsock         = nbtsock;
+	state->request_packet  = talloc_steal(state, packet);
+	state->rec             = talloc_steal(state, rec);
+	state->src_port        = src_port;
+	state->owner_addresses = rec->addresses;
+	state->reg_address     = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
+	state->src_address     = talloc_strdup(state, src_address);
+	if (state->src_address == NULL) goto failed;
+
+	/* send a WACK to the client, specifying the maximum time it could
+	   take to check with the owner, plus some slack */
+	ttl = 5 + 4 * str_list_length(rec->addresses);
+	nbtd_wack_reply(nbtsock, packet, src_address, src_port, ttl);
+
+	/* setup a name query to the first address */
+	state->query.in.name        = *rec->name;
+	state->query.in.dest_addr   = state->owner_addresses[0];
+	state->query.in.broadcast   = False;
+	state->query.in.wins_lookup = True;
+	state->query.in.timeout     = 1;
+	state->query.in.retries     = 2;
+
+	req = nbt_name_query_send(nbtsock, &state->query);
+	if (req == NULL) goto failed;
+
+	req->async.fn = wins_wack_handler;
+	req->async.private = state;
+	return;	
+
+failed:
+	talloc_free(state);
+	nbtd_name_registration_reply(nbtsock, packet, src_address, src_port, NBT_RCODE_SVR);	
+}