/* Unix SMB/CIFS implementation. 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" static struct iface_struct *probed_ifaces; static int total_probed; struct in_addr allones_ip; struct in_addr loopback_ip; static struct interface *local_interfaces; #define ALLONES ((uint32)0xFFFFFFFF) #define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES)) #define MKNETADDR(_IP, _NM) (_IP & _NM) /**************************************************************************** Try and find an interface that matches an ip. If we cannot, return NULL **************************************************************************/ static struct interface *iface_find(struct in_addr ip, BOOL CheckMask) { struct interface *i; if (is_zero_ip(ip)) return local_interfaces; for (i=local_interfaces;i;i=i->next) if (CheckMask) { if (same_net(i->ip,ip,i->nmask)) return i; } else if ((i->ip).s_addr == ip.s_addr) return i; return NULL; } /**************************************************************************** add an interface to the linked list of interfaces ****************************************************************************/ static void add_interface(struct in_addr ip, struct in_addr nmask) { struct interface *iface; if (iface_find(ip, False)) { DEBUG(3,("not adding duplicate interface %s\n",inet_ntoa(ip))); return; } if (ip_equal(nmask, allones_ip)) { DEBUG(3,("not adding non-broadcast interface %s\n",inet_ntoa(ip))); return; } iface = (struct interface *)malloc(sizeof(*iface)); if (!iface) return; ZERO_STRUCTPN(iface); iface->ip = ip; iface->nmask = nmask; iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr); DLIST_ADD(local_interfaces, 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))); } /**************************************************************************** interpret a single element from a interfaces= config line This handles the following different forms: 1) wildcard interface name 2) DNS name 3) IP/masklen 4) ip/mask 5) bcast/mask ****************************************************************************/ static void interpret_interface(const char *token) { struct in_addr ip, nmask; char *p; int i, added=0; zero_ip(&ip); zero_ip(&nmask); /* first check if it is an interface name */ for (i=0;i<total_probed;i++) { if (gen_fnmatch(token, probed_ifaces[i].name) == 0) { add_interface(probed_ifaces[i].ip, probed_ifaces[i].netmask); added = 1; } } if (added) return; /* maybe it is a DNS name */ p = strchr_m(token,'/'); if (!p) { ip = *interpret_addr2(token); for (i=0;i<total_probed;i++) { if (ip.s_addr == probed_ifaces[i].ip.s_addr && !ip_equal(allones_ip, probed_ifaces[i].netmask)) { add_interface(probed_ifaces[i].ip, probed_ifaces[i].netmask); return; } } DEBUG(2,("can't determine netmask for %s\n", token)); return; } /* parse it into an IP address/netmasklength pair */ *p++ = 0; ip = *interpret_addr2(token); if (strlen(p) > 2) { nmask = *interpret_addr2(p); } else { nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES)); } /* maybe the first component was a broadcast address */ if (ip.s_addr == MKBCADDR(ip.s_addr, nmask.s_addr) || ip.s_addr == MKNETADDR(ip.s_addr, nmask.s_addr)) { for (i=0;i<total_probed;i++) { if (same_net(ip, probed_ifaces[i].ip, nmask)) { add_interface(probed_ifaces[i].ip, nmask); return; } } DEBUG(2,("Can't determine ip for broadcast address %s\n", token)); return; } add_interface(ip, nmask); } /**************************************************************************** load the list of network interfaces ****************************************************************************/ void load_interfaces(void) { const char **ptr; int i; struct iface_struct ifaces[MAX_INTERFACES]; ptr = lp_interfaces(); allones_ip = *interpret_addr2("255.255.255.255"); loopback_ip = *interpret_addr2("127.0.0.1"); SAFE_FREE(probed_ifaces); /* dump the current interfaces if any */ while (local_interfaces) { struct interface *iface = local_interfaces; DLIST_REMOVE(local_interfaces, local_interfaces); ZERO_STRUCTPN(iface); SAFE_FREE(iface); } /* probe the kernel for interfaces */ total_probed = get_interfaces(ifaces, MAX_INTERFACES); if (total_probed > 0) { probed_ifaces = memdup(ifaces, sizeof(ifaces[0])*total_probed); } /* if we don't have a interfaces line then use all broadcast capable interfaces except loopback */ if (!ptr || !*ptr || !**ptr) { if (total_probed <= 0) { DEBUG(0,("ERROR: Could not determine network interfaces, you must use a interfaces config line\n")); exit(1); } for (i=0;i<total_probed;i++) { if (probed_ifaces[i].netmask.s_addr != allones_ip.s_addr && probed_ifaces[i].ip.s_addr != loopback_ip.s_addr) { add_interface(probed_ifaces[i].ip, probed_ifaces[i].netmask); } } return; } if (ptr) { while (*ptr) { interpret_interface(*ptr); ptr++; } } if (!local_interfaces) { DEBUG(0,("WARNING: no network interfaces found\n")); } } /**************************************************************************** return True if the list of probed interfaces has changed ****************************************************************************/ BOOL interfaces_changed(void) { int n; struct iface_struct ifaces[MAX_INTERFACES]; n = get_interfaces(ifaces, MAX_INTERFACES); if ((n > 0 )&& (n != total_probed || memcmp(ifaces, probed_ifaces, sizeof(ifaces[0])*n))) { return True; } return False; } /**************************************************************************** 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; } /**************************************************************************** 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; } /**************************************************************************** return bcast of the Nth interface **************************************************************************/ struct in_addr *iface_n_bcast(int n) { struct interface *i; for (i=local_interfaces;i && n;i=i->next) n--; if (i) return &i->bcast; return NULL; } /* 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_ip(struct in_addr ip) { struct interface *i = iface_find(ip, True); return(i ? &i->ip : &local_interfaces->ip); } /* return True if a IP is directly reachable on one of our interfaces */ BOOL iface_local(struct in_addr ip) { return iface_find(ip, True) ? True : False; }