/* 
   Unix SMB/CIFS implementation.

   NBT interface handling

   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 "dlinklist.h"
#include "nbt_server/nbt_server.h"
#include "smbd/service_task.h"
#include "lib/socket/socket.h"


/*
  receive an incoming request and dispatch it to the right place
*/
static void nbtd_request_handler(struct nbt_name_socket *nbtsock, 
				 struct nbt_name_packet *packet, 
				 const char *src_address, int src_port)
{
	/* if its a WINS query then direct to our WINS server if we
	   are running one */
	if ((packet->operation & NBT_FLAG_RECURSION_DESIRED) &&
	    !(packet->operation & NBT_FLAG_BROADCAST) &&
	    lp_wins_support()) {
		nbtd_query_wins(nbtsock, packet, src_address, src_port);
		return;
	}

	/* see if its from one of our own interfaces - if so, then ignore it */
	if (nbtd_self_packet(nbtsock, packet, src_address, src_port)) {
		DEBUG(10,("Ignoring self packet from %s:%d\n", src_address, src_port));
		return;
	}

	/* the request is to us in our role as a B node */
	switch ((enum nbt_opcode)(packet->operation & NBT_OPCODE)) {
	case NBT_OPCODE_QUERY:
		nbtd_request_query(nbtsock, packet, src_address, src_port);
		break;

	case NBT_OPCODE_REGISTER:
	case NBT_OPCODE_REFRESH:
	case NBT_OPCODE_REFRESH2:
		nbtd_request_defense(nbtsock, packet, src_address, src_port);
		break;

	default:
		nbtd_bad_packet(packet, src_address, "Unexpected opcode");
		break;
	}
}



/*
  find a registered name on an interface
*/
struct nbtd_iface_name *nbtd_find_iname(struct nbtd_interface *iface, 
					struct nbt_name *name, 
					uint16_t nb_flags)
{
	struct nbtd_iface_name *iname;
	for (iname=iface->names;iname;iname=iname->next) {
		if (iname->name.type == name->type &&
		    strcmp(name->name, iname->name.name) == 0 &&
		    ((iname->nb_flags & nb_flags) == nb_flags)) {
			return iname;
		}
	}
	return NULL;
}

/*
  start listening on the given address
*/
static NTSTATUS nbtd_add_socket(struct nbtd_server *nbtsrv, 
				const char *bind_address, 
				const char *address, 
				const char *bcast, 
				const char *netmask)
{
	struct nbtd_interface *iface;
	NTSTATUS status;
	struct nbt_name_socket *bcast_nbtsock;

	/*
	  we actually create two sockets. One listens on the broadcast address
	  for the interface, and the other listens on our specific address. This
	  allows us to run with "bind interfaces only" while still receiving 
	  broadcast addresses, and also simplifies matching incoming requests 
	  to interfaces
	*/

	iface = talloc(nbtsrv, struct nbtd_interface);
	NT_STATUS_HAVE_NO_MEMORY(iface);

	iface->nbtsrv        = nbtsrv;
	iface->bcast_address = talloc_steal(iface, bcast);
	iface->ip_address    = talloc_steal(iface, address);
	iface->netmask       = talloc_steal(iface, netmask);
	iface->names         = NULL;

	if (strcmp(netmask, "0.0.0.0") != 0) {
		bcast_nbtsock = nbt_name_socket_init(iface, nbtsrv->task->event_ctx);
		NT_STATUS_HAVE_NO_MEMORY(bcast_nbtsock);

		status = socket_listen(bcast_nbtsock->sock, bcast, lp_nbt_port(), 0, 0);
		if (!NT_STATUS_IS_OK(status)) {
			DEBUG(0,("Failed to bind to %s:%d - %s\n", 
				 bcast, lp_nbt_port(), nt_errstr(status)));
			talloc_free(iface);
			return status;
		}

		nbt_set_incoming_handler(bcast_nbtsock, nbtd_request_handler, iface);
	}

	iface->nbtsock = nbt_name_socket_init(iface, nbtsrv->task->event_ctx);
	NT_STATUS_HAVE_NO_MEMORY(iface->ip_address);

	status = socket_listen(iface->nbtsock->sock, bind_address, lp_nbt_port(), 0, 0);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("Failed to bind to %s:%d - %s\n", 
			 address, lp_nbt_port(), nt_errstr(status)));
		talloc_free(iface);
		return status;
	}

	nbt_set_incoming_handler(iface->nbtsock, nbtd_request_handler, iface);

	if (strcmp(netmask, "0.0.0.0") == 0) {
		DLIST_ADD(nbtsrv->bcast_interface, iface);
	} else {
		DLIST_ADD(nbtsrv->interfaces, iface);
	}

	return NT_STATUS_OK;
}


/*
  setup a socket for talking to our WINS servers
*/
static NTSTATUS nbtd_add_wins_socket(struct nbtd_server *nbtsrv)
{
	struct nbtd_interface *iface;

	iface = talloc_zero(nbtsrv, struct nbtd_interface);
	NT_STATUS_HAVE_NO_MEMORY(iface);

	iface->nbtsrv        = nbtsrv;

	DLIST_ADD(nbtsrv->wins_interface, iface);

	return NT_STATUS_OK;
}


/*
  setup our listening sockets on the configured network interfaces
*/
NTSTATUS nbtd_startup_interfaces(struct nbtd_server *nbtsrv)
{
	int num_interfaces = iface_count();
	int i;
	TALLOC_CTX *tmp_ctx = talloc_new(nbtsrv);
	NTSTATUS status;

	/* if we are allowing incoming packets from any address, then
	   we also need to bind to the wildcard address */
	if (!lp_bind_interfaces_only()) {
		const char *primary_address;

		/* the primary address is the address we will return
		   for non-WINS queries not made on a specific
		   interface */
		if (num_interfaces > 0) {
			primary_address = iface_n_ip(0);
		} else {
			primary_address = sys_inet_ntoa(interpret_addr2(
								lp_netbios_name()));
		}
		primary_address = talloc_strdup(tmp_ctx, primary_address);
		NT_STATUS_HAVE_NO_MEMORY(primary_address);

		status = nbtd_add_socket(nbtsrv, 
					 "0.0.0.0",
					 primary_address,
					 talloc_strdup(tmp_ctx, "255.255.255.255"),
					 talloc_strdup(tmp_ctx, "0.0.0.0"));
		NT_STATUS_NOT_OK_RETURN(status);
	}

	for (i=0; i<num_interfaces; i++) {
		const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
		const char *bcast   = talloc_strdup(tmp_ctx, iface_n_bcast(i));
		const char *netmask = talloc_strdup(tmp_ctx, iface_n_netmask(i));

		status = nbtd_add_socket(nbtsrv, address, address, bcast, netmask);
		NT_STATUS_NOT_OK_RETURN(status);
	}

	if (lp_wins_server_list()) {
		status = nbtd_add_wins_socket(nbtsrv);
		NT_STATUS_NOT_OK_RETURN(status);
	}

	talloc_free(tmp_ctx);

	return NT_STATUS_OK;
}


/*
  form a list of addresses that we should use in name query replies
  we always place the IP in the given interface first
*/
const char **nbtd_address_list(struct nbtd_interface *iface, TALLOC_CTX *mem_ctx)
{
	struct nbtd_server *nbtsrv = iface->nbtsrv;
	const char **ret = NULL;
	struct nbtd_interface *iface2;
	int count = 0;

	if (iface->ip_address) {
		ret = talloc_array(mem_ctx, const char *, 2);
		if (ret == NULL) goto failed;

		ret[0] = talloc_strdup(ret, iface->ip_address);
		if (ret[0] == NULL) goto failed;
		ret[1] = NULL;

		count = 1;
	}

	for (iface2=nbtsrv->interfaces;iface2;iface2=iface2->next) {
		const char **ret2;

		if (iface->ip_address &&
		    strcmp(iface2->ip_address, iface->ip_address) == 0) {
			continue;
		}

		ret2 = talloc_realloc(mem_ctx, ret, const char *, count+2);
		if (ret2 == NULL) goto failed;
		ret = ret2;
		ret[count] = talloc_strdup(ret, iface2->ip_address);
		if (ret[count] == NULL) goto failed;
		count++;
	}
	ret[count] = NULL;
	return ret;

failed:
	talloc_free(ret);
	return NULL;
}