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Unix SMB/CIFS implementation.
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multiple interface handling
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Copyright (C) Andrew Tridgell 1992-2005
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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 3 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, see <http://www.gnu.org/licenses/>.
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#include "system/network.h"
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#include "lib/socket/netif.h"
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#include "../lib/util/dlinklist.h"
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/** used for network interfaces */
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struct interface *next, *prev;
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#define ALLONES ((uint32_t)0xFFFFFFFF)
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address construction based on a patch from fred@datalync.com
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#define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES))
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#define MKNETADDR(_IP, _NM) (_IP & _NM)
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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 interface *interfaces,
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struct in_addr ip, bool CheckMask)
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if (is_zero_ip_v4(ip)) return interfaces;
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for (i=interfaces;i;i=i->next)
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if (same_net_v4(i->ip,ip,i->nmask)) return i;
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} else if (i->ip.s_addr == ip.s_addr) return i;
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/****************************************************************************
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add an interface to the linked list of interfaces
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****************************************************************************/
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static void add_interface(TALLOC_CTX *mem_ctx, struct in_addr ip, struct in_addr nmask, struct interface **interfaces)
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struct interface *iface;
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if (iface_find(*interfaces, ip, false)) {
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DEBUG(3,("not adding duplicate interface %s\n",inet_ntoa(ip)));
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iface = talloc(*interfaces == NULL ? mem_ctx : *interfaces, struct interface);
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bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);
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/* keep string versions too, to avoid people tripping over the implied
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static in inet_ntoa() */
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iface->ip_s = talloc_strdup(iface, inet_ntoa(iface->ip));
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iface->nmask_s = talloc_strdup(iface, inet_ntoa(iface->nmask));
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if (nmask.s_addr != ~0) {
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iface->bcast_s = talloc_strdup(iface, inet_ntoa(bcast));
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DLIST_ADD_END(*interfaces, iface, struct interface *);
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DEBUG(2,("added interface ip=%s nmask=%s\n", iface->ip_s, iface->nmask_s));
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interpret a single element from a interfaces= config line
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This handles the following different forms:
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1) wildcard interface name
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static void interpret_interface(TALLOC_CTX *mem_ctx,
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struct iface_struct *probed_ifaces,
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struct interface **local_interfaces)
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struct in_addr ip, nmask;
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/* first check if it is an interface name */
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for (i=0;i<total_probed;i++) {
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if (gen_fnmatch(token, probed_ifaces[i].name) == 0) {
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add_interface(mem_ctx, probed_ifaces[i].ip,
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probed_ifaces[i].netmask,
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/* maybe it is a DNS name */
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p = strchr_m(token,'/');
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/* don't try to do dns lookups on wildcard names */
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if (strpbrk(token, "*?") != NULL) {
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ip.s_addr = interpret_addr2(token).s_addr;
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for (i=0;i<total_probed;i++) {
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if (ip.s_addr == probed_ifaces[i].ip.s_addr) {
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add_interface(mem_ctx, probed_ifaces[i].ip,
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probed_ifaces[i].netmask,
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DEBUG(2,("can't determine netmask for %s\n", token));
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address = talloc_strdup(mem_ctx, token);
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p = strchr_m(address,'/');
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/* parse it into an IP address/netmasklength pair */
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ip.s_addr = interpret_addr2(address).s_addr;
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nmask.s_addr = interpret_addr2(p).s_addr;
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nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES));
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/* maybe the first component was a broadcast address */
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if (ip.s_addr == MKBCADDR(ip.s_addr, nmask.s_addr) ||
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ip.s_addr == MKNETADDR(ip.s_addr, nmask.s_addr)) {
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for (i=0;i<total_probed;i++) {
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if (same_net_v4(ip, probed_ifaces[i].ip, nmask)) {
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add_interface(mem_ctx, probed_ifaces[i].ip, nmask,
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talloc_free(address);
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DEBUG(2,("Can't determine ip for broadcast address %s\n", address));
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talloc_free(address);
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add_interface(mem_ctx, ip, nmask, local_interfaces);
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talloc_free(address);
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load the list of network interfaces
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void load_interfaces(TALLOC_CTX *mem_ctx, const char **interfaces, struct interface **local_interfaces)
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const char **ptr = interfaces;
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struct iface_struct ifaces[MAX_INTERFACES];
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struct in_addr loopback_ip;
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*local_interfaces = NULL;
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loopback_ip = interpret_addr2("127.0.0.1");
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/* probe the kernel for interfaces */
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total_probed = get_interfaces(ifaces, MAX_INTERFACES);
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/* if we don't have a interfaces line then use all interfaces
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if (!ptr || !*ptr || !**ptr) {
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if (total_probed <= 0) {
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DEBUG(0,("ERROR: Could not determine network interfaces, you must use a interfaces config line\n"));
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for (i=0;i<total_probed;i++) {
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if (ifaces[i].ip.s_addr != loopback_ip.s_addr) {
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add_interface(mem_ctx, ifaces[i].ip,
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ifaces[i].netmask, local_interfaces);
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while (ptr && *ptr) {
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interpret_interface(mem_ctx, *ptr, ifaces, total_probed, local_interfaces);
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if (!*local_interfaces) {
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DEBUG(0,("WARNING: no network interfaces found\n"));
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how many interfaces do we have
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int iface_count(struct interface *ifaces)
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for (i=ifaces;i;i=i->next)
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return IP of the Nth interface
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const char *iface_n_ip(struct interface *ifaces, int n)
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for (i=ifaces;i && n;i=i->next)
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return bcast of the Nth interface
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const char *iface_n_bcast(struct interface *ifaces, int n)
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for (i=ifaces;i && n;i=i->next)
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return netmask of the Nth interface
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const char *iface_n_netmask(struct interface *ifaces, int n)
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for (i=ifaces;i && n;i=i->next)
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return the local IP address that best matches a destination IP, or
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our first interface if none match
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const char *iface_best_ip(struct interface *ifaces, const char *dest)
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struct interface *iface;
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ip.s_addr = interpret_addr(dest);
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iface = iface_find(ifaces, ip, true);
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return iface_n_ip(ifaces, 0);
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return true if an IP is one one of our local networks
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bool iface_is_local(struct interface *ifaces, const char *dest)
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ip.s_addr = interpret_addr(dest);
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if (iface_find(ifaces, ip, true)) {
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return true if a IP matches a IP/netmask pair
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bool iface_same_net(const char *ip1, const char *ip2, const char *netmask)
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return same_net_v4(interpret_addr2(ip1),
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interpret_addr2(ip2),
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interpret_addr2(netmask));