mirror of https://github.com/MidnightCommander/mc
383 lines
10 KiB
C
383 lines
10 KiB
C
/*
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Unix SMB/Netbios implementation.
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Version 1.9.
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multiple interface handling
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Copyright (C) Andrew Tridgell 1992-1998
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "includes.h"
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extern int DEBUGLEVEL;
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struct in_addr ipzero;
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struct in_addr allones_ip;
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struct in_addr loopback_ip;
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static struct in_addr default_ip;
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static struct in_addr default_bcast;
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static struct in_addr default_nmask;
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static BOOL got_ip=False;
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static BOOL got_bcast=False;
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static BOOL got_nmask=False;
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static struct interface *local_interfaces = NULL;
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struct interface *last_iface;
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#define ALLONES ((uint32)0xFFFFFFFF)
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#define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES))
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/****************************************************************************
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calculate the default netmask for an address
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****************************************************************************/
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static void default_netmask(struct in_addr *inm, struct in_addr *iad)
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{
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/*
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** Guess a netmask based on the class of the IP address given.
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*/
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switch((ntohl(iad->s_addr) & 0xE0000000)) {
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case 0x00000000: /* Class A addr */
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case 0x20000000:
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case 0x40000000:
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case 0x60000000:
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inm->s_addr = htonl(0xFF000000);
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break;
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case 0x80000000: /* Class B addr */
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case 0xA0000000:
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inm->s_addr = htonl(0xFFFF0000);
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break;
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case 0xC0000000: /* Class C addr */
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inm->s_addr = htonl(0xFFFFFF00);
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break;
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default: /* ??? */
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inm->s_addr = htonl(0xFFFFFFF0);
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}
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}
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/****************************************************************************
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get the broadcast address for our address
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(troyer@saifr00.ateng.az.honeywell.com)
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****************************************************************************/
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static void get_broadcast(struct in_addr *if_ipaddr,
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struct in_addr *if_bcast,
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struct in_addr *if_nmask)
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{
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uint32 nm;
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short onbc;
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short offbc;
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/* get a default netmask and broadcast */
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default_netmask(if_nmask, if_ipaddr);
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get_netmask(if_ipaddr, if_nmask);
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/* sanity check on the netmask */
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nm = ntohl(if_nmask->s_addr);
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onbc = 0;
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offbc = 0;
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while((onbc + offbc) < 32) {
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if(nm & 0x80000000) {
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onbc++;
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if(offbc) {
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/* already found an off bit, so mask
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is wrong */
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onbc = 34;
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}
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} else {
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offbc++;
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}
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nm <<= 1;
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}
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if ((onbc < 8)||(onbc == 34)) {
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DEBUG(0,("Impossible netmask %s - using defaults\n",
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inet_ntoa(*if_nmask)));
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default_netmask(if_nmask, if_ipaddr);
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}
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/* derive the broadcast assuming a 1's broadcast, as this is what
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all MS operating systems do, we have to comply even if the unix
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box is setup differently */
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if_bcast->s_addr = MKBCADDR(if_ipaddr->s_addr, if_nmask->s_addr);
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DEBUG(4,("Derived broadcast address %s\n", inet_ntoa(*if_bcast)));
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}
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/****************************************************************************
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load a list of network interfaces
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****************************************************************************/
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static void interpret_interfaces(char *s, struct interface **interfaces,
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char *description)
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{
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char *ptr;
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fstring token;
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struct interface *iface;
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struct in_addr ip;
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ptr = s;
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ipzero = *interpret_addr2("0.0.0.0");
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allones_ip = *interpret_addr2("255.255.255.255");
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loopback_ip = *interpret_addr2("127.0.0.1");
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while (next_token(&ptr,token,NULL,sizeof(token))) {
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/* parse it into an IP address/netmasklength pair */
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char *p = strchr(token,'/');
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if (p) *p++ = 0;
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ip = *interpret_addr2(token);
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/* maybe we already have it listed */
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{
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struct interface *i;
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for (i=(*interfaces);i;i=i->next)
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if (ip_equal(ip,i->ip)) break;
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if (i) continue;
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}
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iface = (struct interface *)malloc(sizeof(*iface));
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if (!iface) return;
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iface->ip = ip;
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if (p) {
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if (strlen(p) > 2)
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iface->nmask = *interpret_addr2(p);
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else
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iface->nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES));
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} else {
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default_netmask(&iface->nmask,&iface->ip);
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}
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iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);
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iface->next = NULL;
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if (!(*interfaces)) {
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(*interfaces) = iface;
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} else {
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last_iface->next = iface;
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}
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last_iface = iface;
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DEBUG(2,("Added %s ip=%s ",description,inet_ntoa(iface->ip)));
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DEBUG(2,("bcast=%s ",inet_ntoa(iface->bcast)));
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DEBUG(2,("nmask=%s\n",inet_ntoa(iface->nmask)));
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}
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if (*interfaces) return;
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/* setup a default interface */
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iface = (struct interface *)malloc(sizeof(*iface));
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if (!iface) return;
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iface->next = NULL;
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if (got_ip) {
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iface->ip = default_ip;
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} else {
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get_myname(NULL,&iface->ip);
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}
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if (got_bcast) {
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iface->bcast = default_bcast;
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} else {
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get_broadcast(&iface->ip,&iface->bcast,&iface->nmask);
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}
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if (got_nmask) {
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iface->nmask = default_nmask;
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iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);
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}
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if (iface->bcast.s_addr != MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr)) {
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DEBUG(2,("Warning: inconsistant interface %s\n",inet_ntoa(iface->ip)));
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}
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iface->next = NULL;
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(*interfaces) = last_iface = iface;
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DEBUG(2,("Added interface ip=%s ",inet_ntoa(iface->ip)));
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DEBUG(2,("bcast=%s ",inet_ntoa(iface->bcast)));
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DEBUG(2,("nmask=%s\n",inet_ntoa(iface->nmask)));
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}
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/****************************************************************************
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load the remote and local interfaces
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****************************************************************************/
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void load_interfaces(void)
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{
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/* add the machine's interfaces to local interface structure*/
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interpret_interfaces(lp_interfaces(), &local_interfaces,"interface");
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}
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/****************************************************************************
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override the defaults
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**************************************************************************/
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void iface_set_default(char *ip,char *bcast,char *nmask)
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{
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if (ip) {
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got_ip = True;
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default_ip = *interpret_addr2(ip);
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}
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if (bcast) {
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got_bcast = True;
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default_bcast = *interpret_addr2(bcast);
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}
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if (nmask) {
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got_nmask = True;
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default_nmask = *interpret_addr2(nmask);
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}
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}
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/****************************************************************************
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check if an IP is one of mine
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**************************************************************************/
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BOOL ismyip(struct in_addr ip)
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{
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struct interface *i;
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for (i=local_interfaces;i;i=i->next)
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if (ip_equal(i->ip,ip)) return True;
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return False;
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}
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/****************************************************************************
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check if a packet is from a local (known) net
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**************************************************************************/
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BOOL is_local_net(struct in_addr from)
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{
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struct interface *i;
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for (i=local_interfaces;i;i=i->next)
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if((from.s_addr & i->nmask.s_addr) == (i->ip.s_addr & i->nmask.s_addr))
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return True;
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return False;
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}
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/****************************************************************************
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how many interfaces do we have
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**************************************************************************/
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int iface_count(void)
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{
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int ret = 0;
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struct interface *i;
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for (i=local_interfaces;i;i=i->next)
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ret++;
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return ret;
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}
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/****************************************************************************
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True if we have two or more interfaces.
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**************************************************************************/
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BOOL we_are_multihomed(void)
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{
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static int multi = -1;
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if(multi == -1)
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multi = (iface_count() > 1 ? True : False);
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return multi;
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}
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/****************************************************************************
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return the Nth interface
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**************************************************************************/
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struct interface *get_interface(int n)
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{
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struct interface *i;
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for (i=local_interfaces;i && n;i=i->next)
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n--;
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if (i) return i;
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return NULL;
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}
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/****************************************************************************
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return IP of the Nth interface
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**************************************************************************/
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struct in_addr *iface_n_ip(int n)
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{
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struct interface *i;
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for (i=local_interfaces;i && n;i=i->next)
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n--;
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if (i) return &i->ip;
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return NULL;
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}
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/****************************************************************************
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Try and find an interface that matches an ip. If we cannot, return NULL
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**************************************************************************/
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static struct interface *iface_find(struct in_addr ip)
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{
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struct interface *i;
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if (zero_ip(ip)) return local_interfaces;
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for (i=local_interfaces;i;i=i->next)
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if (same_net(i->ip,ip,i->nmask)) return i;
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return NULL;
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}
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/****************************************************************************
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this function provides a simple hash of the configured interfaces. It is
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used to detect a change in interfaces to tell us whether to discard
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the current wins.dat file.
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Note that the result is independent of the order of the interfaces
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**************************************************************************/
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unsigned iface_hash(void)
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{
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unsigned ret = 0;
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struct interface *i;
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for (i=local_interfaces;i;i=i->next) {
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unsigned x1 = (unsigned)str_checksum(inet_ntoa(i->ip));
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unsigned x2 = (unsigned)str_checksum(inet_ntoa(i->nmask));
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ret ^= (x1 ^ x2);
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}
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return ret;
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}
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/* these 3 functions return the ip/bcast/nmask for the interface
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most appropriate for the given ip address. If they can't find
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an appropriate interface they return the requested field of the
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first known interface. */
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struct in_addr *iface_bcast(struct in_addr ip)
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{
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struct interface *i = iface_find(ip);
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return(i ? &i->bcast : &local_interfaces->bcast);
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}
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struct in_addr *iface_ip(struct in_addr ip)
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{
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struct interface *i = iface_find(ip);
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return(i ? &i->ip : &local_interfaces->ip);
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}
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