winsserver.c

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/* 
   Unix SMB/CIFS implementation.

   core wins server handling

   Copyright (C) Andrew Tridgell	2005
   Copyright (C) Stefan Metzmacher	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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "nbt_server/nbt_server.h"
#include "nbt_server/wins/winsdb.h"
#include "nbt_server/wins/winsserver.h"
#include "librpc/gen_ndr/ndr_nbt.h"
#include "system/time.h"
#include "libcli/composite/composite.h"
#include "smbd/service_task.h"
#include "system/network.h"
#include "lib/socket/socket.h"
#include "lib/socket/netif.h"
#include "lib/ldb/include/ldb.h"
#include "param/param.h"
#include "libcli/resolve/resolve.h"

/*
  work out the ttl we will use given a client requested ttl
*/
uint32_t wins_server_ttl(struct wins_server *winssrv, uint32_t ttl)
{
	ttl = MIN(ttl, winssrv->config.max_renew_interval);
	ttl = MAX(ttl, winssrv->config.min_renew_interval);
	return ttl;
}

static enum wrepl_name_type wrepl_type(uint16_t nb_flags, struct nbt_name *name, bool mhomed)
{
	/* this copes with the nasty hack that is the type 0x1c name */
	if (name->type == NBT_NAME_LOGON) {
		return WREPL_TYPE_SGROUP;
	}
	if (nb_flags & NBT_NM_GROUP) {
		return WREPL_TYPE_GROUP;
	}
	if (mhomed) {
		return WREPL_TYPE_MHOMED;
	}
	return WREPL_TYPE_UNIQUE;
}

/*
  register a new name with WINS
*/
static uint8_t wins_register_new(struct nbt_name_socket *nbtsock, 
				 struct nbt_name_packet *packet, 
				 const struct socket_address *src,
				 enum wrepl_name_type type)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
	uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	struct winsdb_record rec;
	enum wrepl_name_node node;

#define WREPL_NODE_NBT_FLAGS(nb_flags) \
	((nb_flags & NBT_NM_OWNER_TYPE)>>13)

	node	= WREPL_NODE_NBT_FLAGS(nb_flags);

	rec.name		= name;
	rec.type		= type;
	rec.state		= WREPL_STATE_ACTIVE;
	rec.node		= node;
	rec.is_static		= false;
	rec.expire_time		= time(NULL) + ttl;
	rec.version		= 0; /* will be allocated later */
	rec.wins_owner		= NULL; /* will be set later */
	rec.registered_by	= src->addr;
	rec.addresses		= winsdb_addr_list_make(packet);
	if (rec.addresses == NULL) return NBT_RCODE_SVR;

	rec.addresses     = winsdb_addr_list_add(winssrv->wins_db,
						 &rec, rec.addresses,
						 address,
						 winssrv->wins_db->local_owner,
						 rec.expire_time,
						 true);
	if (rec.addresses == NULL) return NBT_RCODE_SVR;

	DEBUG(4,("WINS: accepted registration of %s with address %s\n",
		 nbt_name_string(packet, name), rec.addresses[0]->address));
	
	return winsdb_add(winssrv->wins_db, &rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);
}


/*
  update the ttl on an existing record
*/
static uint8_t wins_update_ttl(struct nbt_name_socket *nbtsock, 
			       struct nbt_name_packet *packet, 
			       struct winsdb_record *rec,
			       struct winsdb_addr *winsdb_addr,
			       const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	uint32_t modify_flags = 0;

	rec->expire_time   = time(NULL) + ttl;
	rec->registered_by = src->addr;

	if (winsdb_addr) {
		rec->addresses = winsdb_addr_list_add(winssrv->wins_db,
						      rec, rec->addresses,
						      winsdb_addr->address,
						      winssrv->wins_db->local_owner,
						      rec->expire_time,
						      true);
		if (rec->addresses == NULL) return NBT_RCODE_SVR;
	}

	if (strcmp(winssrv->wins_db->local_owner, rec->wins_owner) != 0) {
		modify_flags = WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP;
	}

	DEBUG(5,("WINS: refreshed registration of %s at %s\n",
		 nbt_name_string(packet, rec->name), address));
	
	return winsdb_modify(winssrv->wins_db, rec, modify_flags);
}

/*
  do a sgroup merge
*/
static uint8_t wins_sgroup_merge(struct nbt_name_socket *nbtsock, 
				 struct nbt_name_packet *packet, 
			         struct winsdb_record *rec,
			         const char *address,
			         const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);

	rec->expire_time   = time(NULL) + ttl;
	rec->registered_by = src->addr;

	rec->addresses     = winsdb_addr_list_add(winssrv->wins_db,
						  rec, rec->addresses,
						  address,
						  winssrv->wins_db->local_owner,
						  rec->expire_time,
						  true);
	if (rec->addresses == NULL) return NBT_RCODE_SVR;

	DEBUG(5,("WINS: sgroup merge of %s at %s\n",
		 nbt_name_string(packet, rec->name), address));
	
	return winsdb_modify(winssrv->wins_db, rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);
}

struct wack_state {
	struct wins_server *winssrv;
	struct nbt_name_socket *nbtsock;
	struct nbt_name_packet *request_packet;
	struct winsdb_record *rec;
	struct socket_address *src;
	const char *reg_address;
	enum wrepl_name_type new_type;
	struct wins_challenge_io io;
	NTSTATUS status;
};

/*
  deny a registration request
*/
static void wins_wack_deny(struct wack_state *s)
{
	nbtd_name_registration_reply(s->nbtsock, s->request_packet, 
				     s->src, NBT_RCODE_ACT);
	DEBUG(4,("WINS: denied name registration request for %s from %s:%d\n",
		 nbt_name_string(s, s->rec->name), s->src->addr, s->src->port));
	talloc_free(s);
}

/*
  allow a registration request
*/
static void wins_wack_allow(struct wack_state *s)
{
	NTSTATUS status;
	uint32_t ttl = wins_server_ttl(s->winssrv, s->request_packet->additional[0].ttl);
	struct winsdb_record *rec = s->rec, *rec2;
	uint32_t i,j;

	status = winsdb_lookup(s->winssrv->wins_db, rec->name, s, &rec2);
	if (!NT_STATUS_IS_OK(status) ||
	    rec2->version != rec->version ||
	    strcmp(rec2->wins_owner, rec->wins_owner) != 0) {
		DEBUG(5,("WINS: record %s changed during WACK - failing registration\n",
			 nbt_name_string(s, rec->name)));
		wins_wack_deny(s);
		return;
	}

	/*
	 * if the old name owner doesn't hold the name anymore
	 * handle the request as new registration for the new name owner
	 */
	if (!NT_STATUS_IS_OK(s->status)) {
		uint8_t rcode;

		winsdb_delete(s->winssrv->wins_db, rec);
		rcode = wins_register_new(s->nbtsock, s->request_packet, s->src, s->new_type);
		if (rcode != NBT_RCODE_OK) {
			DEBUG(1,("WINS: record %s failed to register as new during WACK\n",
				 nbt_name_string(s, rec->name)));
			wins_wack_deny(s);
			return;
		}
		goto done;
	}

	rec->expire_time = time(NULL) + ttl;
	rec->registered_by = s->src->addr;

	/*
	 * now remove all addresses that're the client doesn't hold anymore
	 * and update the time stamp and owner for the ownes that are still there
	 */
	for (i=0; rec->addresses[i]; i++) {
		bool found = false;
		for (j=0; j < s->io.out.num_addresses; j++) {
			if (strcmp(rec->addresses[i]->address, s->io.out.addresses[j]) != 0) continue;

			found = true;
			break;
		}
		if (found) {
			rec->addresses = winsdb_addr_list_add(s->winssrv->wins_db,
							      rec, rec->addresses,
							      s->reg_address,
							      s->winssrv->wins_db->local_owner,
							      rec->expire_time,
							      true);
			if (rec->addresses == NULL) goto failed;
			continue;
		}

		winsdb_addr_list_remove(rec->addresses, rec->addresses[i]->address);
	}

	rec->addresses = winsdb_addr_list_add(s->winssrv->wins_db,
					      rec, rec->addresses,
					      s->reg_address,
					      s->winssrv->wins_db->local_owner,
					      rec->expire_time,
					      true);
	if (rec->addresses == NULL) goto failed;

	/* if we have more than one address, this becomes implicit a MHOMED record */
	if (winsdb_addr_list_length(rec->addresses) > 1) {
		rec->type = WREPL_TYPE_MHOMED;
	}

	winsdb_modify(s->winssrv->wins_db, rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);

	DEBUG(4,("WINS: accepted registration of %s with address %s\n",
		 nbt_name_string(s, rec->name), s->reg_address));

done:
	nbtd_name_registration_reply(s->nbtsock, s->request_packet, 
				     s->src, NBT_RCODE_OK);
failed:
	talloc_free(s);
}

/*
  called when a name query to a current owner completes
*/
static void wack_wins_challenge_handler(struct composite_context *c_req)
{
	struct wack_state *s = talloc_get_type(c_req->async.private_data,
					       struct wack_state);
	bool found;
	uint32_t i;

	s->status = wins_challenge_recv(c_req, s, &s->io);

	/*
	 * if the owner denies it holds the name, then allow
	 * the registration
	 */
	if (!NT_STATUS_IS_OK(s->status)) {
		wins_wack_allow(s);
		return;
	}

	if (s->new_type == WREPL_TYPE_GROUP || s->new_type == WREPL_TYPE_SGROUP) {
		DEBUG(1,("WINS: record %s failed to register as group type(%u) during WACK, it's still type(%u)\n",
			 nbt_name_string(s, s->rec->name), s->new_type, s->rec->type));
		wins_wack_deny(s);
		return;
	}

	/*
	 * if the owner still wants the name and doesn't reply
	 * with the address trying to be registered, then deny
	 * the registration
	 */
	found = false;
	for (i=0; i < s->io.out.num_addresses; i++) {
		if (strcmp(s->reg_address, s->io.out.addresses[i]) != 0) continue;

		found = true;
		break;
	}
	if (!found) {
		wins_wack_deny(s);
		return;
	}

	wins_wack_allow(s);
	return;
}


/*
  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
*/
static void wins_register_wack(struct nbt_name_socket *nbtsock, 
			       struct nbt_name_packet *packet, 
			       struct winsdb_record *rec,
			       struct socket_address *src,
			       enum wrepl_name_type new_type)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct wack_state *s;
	struct composite_context *c_req;
	uint32_t ttl;

	s = talloc_zero(nbtsock, struct wack_state);
	if (s == NULL) goto failed;

	/* package up the state variables for this wack request */
	s->winssrv		= winssrv;
	s->nbtsock		= nbtsock;
	s->request_packet	= talloc_steal(s, packet);
	s->rec			= talloc_steal(s, rec);
	s->reg_address		= packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	s->new_type		= new_type;
	s->src		        = src;
	if (talloc_reference(s, src) == NULL) goto failed;

	s->io.in.nbtd_server	= iface->nbtsrv;
	s->io.in.nbt_port       = lp_nbt_port(iface->nbtsrv->task->lp_ctx);
	s->io.in.event_ctx	= iface->nbtsrv->task->event_ctx;
	s->io.in.name		= rec->name;
	s->io.in.num_addresses	= winsdb_addr_list_length(rec->addresses);
	s->io.in.addresses	= winsdb_addr_string_list(s, rec->addresses);
	if (s->io.in.addresses == 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 * winsdb_addr_list_length(rec->addresses);
	nbtd_wack_reply(nbtsock, packet, src, ttl);

	/*
	 * send the challenge to the old addresses
	 */
	c_req = wins_challenge_send(s, &s->io);
	if (c_req == NULL) goto failed;

	c_req->async.fn			= wack_wins_challenge_handler;
	c_req->async.private_data	= s;
	return;

failed:
	talloc_free(s);
	nbtd_name_registration_reply(nbtsock, packet, src, NBT_RCODE_SVR);
}

/*
  register a name
*/
static void nbtd_winsserver_register(struct nbt_name_socket *nbtsock, 
				     struct nbt_name_packet *packet, 
				     struct socket_address *src)
{
	NTSTATUS status;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	struct winsdb_record *rec;
	uint8_t rcode = NBT_RCODE_OK;
	uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	bool mhomed = ((packet->operation & NBT_OPCODE) == NBT_OPCODE_MULTI_HOME_REG);
	enum wrepl_name_type new_type = wrepl_type(nb_flags, name, mhomed);
	struct winsdb_addr *winsdb_addr = NULL;

	/*
	 * as a special case, the local master browser name is always accepted
	 * for registration, but never stored, but w2k3 stores it if it's registered
	 * as a group name, (but a query for the 0x1D name still returns not found!)
	 */
	if (name->type == NBT_NAME_MASTER && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_OK;
		goto done;
	}

	/* w2k3 refuses 0x1B names with marked as group */
	if (name->type == NBT_NAME_PDC && (nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	/* w2k3 refuses 0x1C names with out marked as group */
	if (name->type == NBT_NAME_LOGON && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	/* w2k3 refuses 0x1E names with out marked as group */
	if (name->type == NBT_NAME_BROWSER && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	status = winsdb_lookup(winssrv->wins_db, name, packet, &rec);
	if (NT_STATUS_EQUAL(NT_STATUS_OBJECT_NAME_NOT_FOUND, status)) {
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	} else if (!NT_STATUS_IS_OK(status)) {
		rcode = NBT_RCODE_SVR;
		goto done;
	} else if (rec->is_static) {
		if (rec->type == WREPL_TYPE_GROUP || rec->type == WREPL_TYPE_SGROUP) {
			rcode = NBT_RCODE_OK;
			goto done;
		}
		rcode = NBT_RCODE_ACT;
		goto done;
	}

	if (rec->type == WREPL_TYPE_GROUP) {
		if (new_type != WREPL_TYPE_GROUP) {
			DEBUG(2,("WINS: Attempt to register name %s as non normal group(%u)"
				 " while a normal group is already there\n",
				 nbt_name_string(packet, name), new_type));
			rcode = NBT_RCODE_ACT;
			goto done;
		}

		if (rec->state == WREPL_STATE_ACTIVE) {
			/* TODO: is this correct? */
			rcode = wins_update_ttl(nbtsock, packet, rec, NULL, src);
			goto done;
		}

		/* TODO: is this correct? */
		winsdb_delete(winssrv->wins_db, rec);
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	}

	if (rec->state != WREPL_STATE_ACTIVE) {
		winsdb_delete(winssrv->wins_db, rec);
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	}