/*    Unix SMB/Netbios implementation.   Version 1.9.   multiple interface handling   Copyright (C) Andrew Tridgell 1992-1998      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"extern int DEBUGLEVEL;struct in_addr ipzero;struct in_addr allones_ip;struct in_addr loopback_ip;static struct in_addr default_ip;static struct in_addr default_bcast;static struct in_addr default_nmask;static BOOL got_ip=False;static BOOL got_bcast=False;static BOOL got_nmask=False;static struct interface *local_interfaces  = NULL;struct interface *last_iface;#define ALLONES  ((uint32)0xFFFFFFFF)#define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES))/****************************************************************************calculate the default netmask for an address****************************************************************************/static void default_netmask(struct in_addr *inm, struct in_addr *iad){	/*	** Guess a netmask based on the class of the IP address given.	*/	switch((ntohl(iad->s_addr) & 0xE0000000)) {        case 0x00000000:     /* Class A addr */        case 0x20000000:        case 0x40000000:        case 0x60000000:		inm->s_addr = htonl(0xFF000000);		break;			case 0x80000000:	/* Class B addr */        case 0xA0000000:		inm->s_addr = htonl(0xFFFF0000);		break;			case 0xC0000000:	/* Class C addr */		inm->s_addr = htonl(0xFFFFFF00);		break;			default:		/* ??? */		inm->s_addr = htonl(0xFFFFFFF0);        }}/****************************************************************************  get the broadcast address for our address (troyer@saifr00.ateng.az.honeywell.com)****************************************************************************/static void get_broadcast(struct in_addr *if_ipaddr,			  struct in_addr *if_bcast,			  struct in_addr *if_nmask){  	uint32 nm;	short onbc;	short offbc;	/* get a default netmask and broadcast */	default_netmask(if_nmask, if_ipaddr);	get_netmask(if_ipaddr, if_nmask);	/* sanity check on the netmask */	nm = ntohl(if_nmask->s_addr);	onbc = 0;	offbc = 0;	while((onbc + offbc) < 32) {		if(nm & 0x80000000) {			onbc++;			if(offbc) {				/* already found an off bit, so mask                                   is wrong */				onbc = 34;			}		} else {			offbc++;		}		nm <<= 1;	}	if ((onbc < 8)||(onbc == 34)) {		DEBUG(0,("Impossible netmask %s - using defaults\n",			 inet_ntoa(*if_nmask)));		default_netmask(if_nmask, if_ipaddr);      	}	/* derive the broadcast assuming a 1's broadcast, as this is what	   all MS operating systems do, we have to comply even if the unix	   box is setup differently */	if_bcast->s_addr = MKBCADDR(if_ipaddr->s_addr, if_nmask->s_addr);  	DEBUG(4,("Derived broadcast address %s\n", inet_ntoa(*if_bcast)));}/****************************************************************************load a list of network interfaces****************************************************************************/static void interpret_interfaces(char *s, struct interface **interfaces,		char *description){  char *ptr;  fstring token;  struct interface *iface;  struct in_addr ip;  ptr = s;  ipzero = *interpret_addr2("0.0.0.0");  allones_ip = *interpret_addr2("255.255.255.255");  loopback_ip = *interpret_addr2("127.0.0.1");  while (next_token(&ptr,token,NULL,sizeof(token))) {    /* parse it into an IP address/netmasklength pair */    char *p = strchr(token,'/');    if (p) *p++ = 0;    ip = *interpret_addr2(token);    /* maybe we already have it listed */    {      struct interface *i;      for (i=(*interfaces);i;i=i->next)	if (ip_equal(ip,i->ip)) break;      if (i) continue;    }    iface = (struct interface *)malloc(sizeof(*iface));    if (!iface) return;    iface->ip = ip;    if (p) {      if (strlen(p) > 2)       iface->nmask = *interpret_addr2(p);      else       iface->nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES));    } else {      default_netmask(&iface->nmask,&iface->ip);    }    iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);    iface->next = NULL;    if (!(*interfaces)) {      (*interfaces) = iface;    } else {      last_iface->next = iface;    }    last_iface = iface;    DEBUG(2,("Added %s ip=%s ",description,inet_ntoa(iface->ip)));    DEBUG(2,("bcast=%s ",inet_ntoa(iface->bcast)));    DEBUG(2,("nmask=%s\n",inet_ntoa(iface->nmask)));	       }  if (*interfaces) return;  /* setup a default interface */  iface = (struct interface *)malloc(sizeof(*iface));  if (!iface) return;  iface->next = NULL;  if (got_ip) {    iface->ip = default_ip;  } else {    get_myname(NULL,&iface->ip);  }  if (got_bcast) {    iface->bcast = default_bcast;  } else {    get_broadcast(&iface->ip,&iface->bcast,&iface->nmask);  }  if (got_nmask) {    iface->nmask = default_nmask;    iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);  }  if (iface->bcast.s_addr != MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr)) {    DEBUG(2,("Warning: inconsistant interface %s\n",inet_ntoa(iface->ip)));  }  iface->next = NULL;  (*interfaces) = last_iface = iface;  DEBUG(2,("Added interface ip=%s ",inet_ntoa(iface->ip)));  DEBUG(2,("bcast=%s ",inet_ntoa(iface->bcast)));  DEBUG(2,("nmask=%s\n",inet_ntoa(iface->nmask)));	     }/****************************************************************************load the remote and local interfaces****************************************************************************/void load_interfaces(void){  /* add the machine's interfaces to local interface structure*/  interpret_interfaces(lp_interfaces(), &local_interfaces,"interface");}/****************************************************************************  override the defaults  **************************************************************************/void iface_set_default(char *ip,char *bcast,char *nmask){  if (ip) {    got_ip = True;    default_ip = *interpret_addr2(ip);  }  if (bcast) {    got_bcast = True;    default_bcast = *interpret_addr2(bcast);  }  if (nmask) {    got_nmask = True;    default_nmask = *interpret_addr2(nmask);  }}/****************************************************************************  check if an IP is one of mine  **************************************************************************/BOOL ismyip(struct in_addr ip){  struct interface *i;  for (i=local_interfaces;i;i=i->next)    if (ip_equal(i->ip,ip)) return True;  return False;}/****************************************************************************  check if a packet is from a local (known) net  **************************************************************************/BOOL is_local_net(struct in_addr from){  struct interface *i;  for (i=local_interfaces;i;i=i->next)    if((from.s_addr & i->nmask.s_addr) == (i->ip.s_addr & i->nmask.s_addr))      return True;  return False;}/****************************************************************************  how many interfaces do we have  **************************************************************************/int iface_count(void){  int ret = 0;  struct interface *i;  for (i=local_interfaces;i;i=i->next)    ret++;  return ret;}/**************************************************************************** True if we have two or more interfaces.  **************************************************************************/BOOL we_are_multihomed(void){  static int multi = -1;  if(multi == -1)    multi = (iface_count() > 1 ? True : False);  return multi;}/****************************************************************************  return the Nth interface  **************************************************************************/struct interface *get_interface(int n){   struct interface *i;    for (i=local_interfaces;i && n;i=i->next)    n--;  if (i) return i;  return NULL;}/****************************************************************************  return IP of the Nth interface  **************************************************************************/struct in_addr *iface_n_ip(int n){  struct interface *i;    for (i=local_interfaces;i && n;i=i->next)    n--;  if (i) return &i->ip;  return NULL;}/****************************************************************************Try and find an interface that matches an ip. If we cannot, return NULL  **************************************************************************/static struct interface *iface_find(struct in_addr ip){  struct interface *i;  if (zero_ip(ip)) return local_interfaces;  for (i=local_interfaces;i;i=i->next)    if (same_net(i->ip,ip,i->nmask)) return i;  return NULL;}/****************************************************************************this function provides a simple hash of the configured interfaces. It isused to detect a change in interfaces to tell us whether to discardthe current wins.dat file.Note that the result is independent of the order of the interfaces  **************************************************************************/unsigned iface_hash(void){	unsigned ret = 0;	struct interface *i;	for (i=local_interfaces;i;i=i->next) {		unsigned x1 = (unsigned)str_checksum(inet_ntoa(i->ip));		unsigned x2 = (unsigned)str_checksum(inet_ntoa(i->nmask));		ret ^= (x1 ^ x2);	}	return ret;}/* these 3 functions return the ip/bcast/nmask for the interface   most appropriate for the given ip address. If they can't find   an appropriate interface they return the requested field of the   first known interface. */struct in_addr *iface_bcast(struct in_addr ip){  struct interface *i = iface_find(ip);  return(i ? &i->bcast : &local_interfaces->bcast);}struct in_addr *iface_ip(struct in_addr ip){  struct interface *i = iface_find(ip);  return(i ? &i->ip : &local_interfaces->ip);}