packet.c

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/* 
   Unix SMB/CIFS implementation.

   packet utility functions

   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 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 "smbd/service_task.h"
#include "lib/socket/socket.h"
#include "librpc/gen_ndr/ndr_nbt.h"
#include "param/param.h"

/*
  we received a badly formed packet - log it
*/
void nbtd_bad_packet(struct nbt_name_packet *packet, 
		     const struct socket_address *src, const char *reason)
{
	DEBUG(2,("nbtd: bad packet '%s' from %s:%d\n", reason, src->addr, src->port));
	if (DEBUGLVL(5)) {
		NDR_PRINT_DEBUG(nbt_name_packet, packet);		
	}
}


/*
  see if an incoming packet is a broadcast packet from one of our own
  interfaces
*/
bool nbtd_self_packet_and_bcast(struct nbt_name_socket *nbtsock, 
				struct nbt_name_packet *packet, 
				const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);

	/* if its not a broadcast then its not considered a self packet */
	if (!(packet->operation & NBT_FLAG_BROADCAST)) {
		return false;
	}

	/* 
	 * this uses the fact that iface->nbtsock is the unicast listen address
	 * if the interface isn't the global bcast interface
	 *
	 * so if the request was directed to the unicast address it isn't a broadcast
	 * message
	 */
	if (iface->nbtsock == nbtsock &&
	    iface != iface->nbtsrv->bcast_interface) {
		return false;
	}

	return nbtd_self_packet(nbtsock, packet, src);
}

bool nbtd_self_packet(struct nbt_name_socket *nbtsock, 
		      struct nbt_name_packet *packet, 
		      const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;
	
	/* if its not from the nbt port, then it wasn't a broadcast from us */
	if (src->port != lp_nbt_port(iface->nbtsrv->task->lp_ctx)) {
		return false;
	}

	/* we have to loop over our interface list, seeing if its from
	   one of our own interfaces */
	for (iface=nbtsrv->interfaces;iface;iface=iface->next) {
		if (strcmp(src->addr, iface->ip_address) == 0) {
			return true;
		}
	}

	return false;
}


/*
  send a name query reply
*/
void nbtd_name_query_reply(struct nbt_name_socket *nbtsock, 
			   struct nbt_name_packet *request_packet, 
			   struct socket_address *src,
			   struct nbt_name *name, uint32_t ttl,
			   uint16_t nb_flags, const char **addresses)
{
	struct nbt_name_packet *packet;
	size_t num_addresses = str_list_length(addresses);
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;
	int i;

	if (num_addresses == 0) {
		DEBUG(3,("No addresses in name query reply - failing\n"));
		return;
	}

	packet = talloc_zero(nbtsock, struct nbt_name_packet);
	if (packet == NULL) return;

	packet->name_trn_id = request_packet->name_trn_id;
	packet->ancount = 1;
	packet->operation = 
		NBT_FLAG_REPLY | 
		NBT_OPCODE_QUERY | 
		NBT_FLAG_AUTHORITIVE |
		NBT_FLAG_RECURSION_DESIRED |
		NBT_FLAG_RECURSION_AVAIL;

	packet->answers = talloc_array(packet, struct nbt_res_rec, 1);
	if (packet->answers == NULL) goto failed;

	packet->answers[0].name     = *name;
	packet->answers[0].rr_type  = NBT_QTYPE_NETBIOS;
	packet->answers[0].rr_class = NBT_QCLASS_IP;
	packet->answers[0].ttl      = ttl;
	packet->answers[0].rdata.netbios.length = num_addresses*6;
	packet->answers[0].rdata.netbios.addresses = 
		talloc_array(packet->answers, struct nbt_rdata_address, num_addresses);
	if (packet->answers[0].rdata.netbios.addresses == NULL) goto failed;

	for (i=0;i<num_addresses;i++) {
		struct nbt_rdata_address *addr = 
			&packet->answers[0].rdata.netbios.addresses[i];
		addr->nb_flags = nb_flags;
		addr->ipaddr = talloc_strdup(packet->answers, addresses[i]);
		if (addr->ipaddr == NULL) goto failed;
	}

	DEBUG(7,("Sending name query reply for %s at %s to %s:%d\n", 
		 nbt_name_string(packet, name), addresses[0], src->addr, src->port));
	
	nbtsrv->stats.total_sent++;
	nbt_name_reply_send(nbtsock, src, packet);

failed:
	talloc_free(packet);
}


/*
  send a negative name query reply
*/
void nbtd_negative_name_query_reply(struct nbt_name_socket *nbtsock, 
				    struct nbt_name_packet *request_packet, 
				    struct socket_address *src)
{
	struct nbt_name_packet *packet;
	struct nbt_name *name = &request_packet->questions[0].name;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;

	packet = talloc_zero(nbtsock, struct nbt_name_packet);
	if (packet == NULL) return;

	packet->name_trn_id = request_packet->name_trn_id;
	packet->ancount = 1;
	packet->operation = 
		NBT_FLAG_REPLY | 
		NBT_OPCODE_QUERY | 
		NBT_FLAG_AUTHORITIVE |
		NBT_RCODE_NAM;

	packet->answers = talloc_array(packet, struct nbt_res_rec, 1);
	if (packet->answers == NULL) goto failed;

	packet->answers[0].name      = *name;
	packet->answers[0].rr_type   = NBT_QTYPE_NULL;
	packet->answers[0].rr_class  = NBT_QCLASS_IP;
	packet->answers[0].ttl       = 0;
	ZERO_STRUCT(packet->answers[0].rdata);

	DEBUG(7,("Sending negative name query reply for %s to %s:%d\n", 
		 nbt_name_string(packet, name), src->addr, src->port));
	
	nbtsrv->stats.total_sent++;
	nbt_name_reply_send(nbtsock, src, packet);

failed:
	talloc_free(packet);
}

/*
  send a name registration reply
*/
void nbtd_name_registration_reply(struct nbt_name_socket *nbtsock, 
				  struct nbt_name_packet *request_packet, 
				  struct socket_address *src,
				  uint8_t rcode)
{
	struct nbt_name_packet *packet;
	struct nbt_name *name = &request_packet->questions[0].name;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;

	packet = talloc_zero(nbtsock, struct nbt_name_packet);
	if (packet == NULL) return;

	packet->name_trn_id = request_packet->name_trn_id;
	packet->ancount = 1;
	packet->operation = 
		NBT_FLAG_REPLY | 
		NBT_OPCODE_REGISTER |
		NBT_FLAG_AUTHORITIVE |
		NBT_FLAG_RECURSION_DESIRED |
		NBT_FLAG_RECURSION_AVAIL |
		rcode;
	
	packet->answers = talloc_array(packet, struct nbt_res_rec, 1);
	if (packet->answers == NULL) goto failed;

	packet->answers[0].name     = *name;
	packet->answers[0].rr_type  = NBT_QTYPE_NETBIOS;
	packet->answers[0].rr_class = NBT_QCLASS_IP;
	packet->answers[0].ttl      = request_packet->additional[0].ttl;
	packet->answers[0].rdata    = request_packet->additional[0].rdata;

	DEBUG(7,("Sending %s name registration reply for %s to %s:%d\n", 
		 rcode==0?"positive":"negative",
		 nbt_name_string(packet, name), src->addr, src->port));
	
	nbtsrv->stats.total_sent++;
	nbt_name_reply_send(nbtsock, src, packet);

failed:
	talloc_free(packet);
}


/*
  send a name release reply
*/
void nbtd_name_release_reply(struct nbt_name_socket *nbtsock, 
			     struct nbt_name_packet *request_packet, 
			     struct socket_address *src,
			     uint8_t rcode)
{
	struct nbt_name_packet *packet;
	struct nbt_name *name = &request_packet->questions[0].name;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;

	packet = talloc_zero(nbtsock, struct nbt_name_packet);
	if (packet == NULL) return;

	packet->name_trn_id = request_packet->name_trn_id;
	packet->ancount = 1;
	packet->operation = 
		NBT_FLAG_REPLY | 
		NBT_OPCODE_RELEASE |
		NBT_FLAG_AUTHORITIVE |
		rcode;
	
	packet->answers = talloc_array(packet, struct nbt_res_rec, 1);
	if (packet->answers == NULL) goto failed;

	packet->answers[0].name     = *name;
	packet->answers[0].rr_type  = NBT_QTYPE_NETBIOS;
	packet->answers[0].rr_class = NBT_QCLASS_IP;
	packet->answers[0].ttl      = request_packet->additional[0].ttl;
	packet->answers[0].rdata    = request_packet->additional[0].rdata;

	DEBUG(7,("Sending %s name release reply for %s to %s:%d\n", 
		 rcode==0?"positive":"negative",
		 nbt_name_string(packet, name), src->addr, src->port));
	
	nbtsrv->stats.total_sent++;
	nbt_name_reply_send(nbtsock, src, packet);

failed:
	talloc_free(packet);
}


/*
  send a WACK reply
*/
void nbtd_wack_reply(struct nbt_name_socket *nbtsock, 
		     struct nbt_name_packet *request_packet, 
		     struct socket_address *src,
		     uint32_t ttl)
{
	struct nbt_name_packet *packet;
	struct nbt_name *name = &request_packet->questions[0].name;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private, 
						       struct nbtd_interface);
	struct nbtd_server *nbtsrv = iface->nbtsrv;

	packet = talloc_zero(nbtsock, struct nbt_name_packet);
	if (packet == NULL) return;

	packet->name_trn_id = request_packet->name_trn_id;
	packet->ancount = 1;
	packet->operation = 
		NBT_FLAG_REPLY | 
		NBT_OPCODE_WACK |
		NBT_FLAG_AUTHORITIVE;
	
	packet->answers = talloc_array(packet, struct nbt_res_rec, 1);
	if (packet->answers == NULL) goto failed;

	packet->answers[0].name              = *name;
	packet->answers[0].rr_type           = NBT_QTYPE_NETBIOS;
	packet->answers[0].rr_class          = NBT_QCLASS_IP;
	packet->answers[0].ttl               = ttl;
	packet->answers[0].rdata.data.length = 2;
	packet->answers[0].rdata.data.data   = talloc_array(packet, uint8_t, 2);
	if (packet->answers[0].rdata.data.data == NULL) goto failed;
	RSSVAL(packet->answers[0].rdata.data.data, 0, request_packet->operation);

	DEBUG(7,("Sending WACK reply for %s to %s:%d\n", 
		 nbt_name_string(packet, name), src->addr, src->port));
	
	nbtsrv->stats.total_sent++;
	nbt_name_reply_send(nbtsock, src, packet);

failed:
	talloc_free(packet);
}