/* Unix SMB/CIFS implementation. multiple interface handling Copyright (C) Andrew Tridgell 1992-2005 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 3 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, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #include "system/network.h" #include "lib/socket/netif.h" #include "../lib/util/dlinklist.h" /** used for network interfaces */ struct interface { struct interface *next, *prev; struct in_addr ip; struct in_addr nmask; const char *ip_s; const char *bcast_s; const char *nmask_s; }; #define ALLONES ((uint32_t)0xFFFFFFFF) /* address construction based on a patch from fred@datalync.com */ #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 interface *interfaces, struct in_addr ip, bool CheckMask) { struct interface *i; if (is_zero_ip_v4(ip)) return interfaces; for (i=interfaces;i;i=i->next) if (CheckMask) { if (same_net_v4(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(TALLOC_CTX *mem_ctx, struct in_addr ip, struct in_addr nmask, struct interface **interfaces) { struct interface *iface; struct in_addr bcast; if (iface_find(*interfaces, ip, false)) { DEBUG(3,("not adding duplicate interface %s\n",inet_ntoa(ip))); return; } iface = talloc(*interfaces == NULL ? mem_ctx : *interfaces, struct interface); if (iface == NULL) return; ZERO_STRUCTPN(iface); iface->ip = ip; iface->nmask = nmask; bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr); /* keep string versions too, to avoid people tripping over the implied static in inet_ntoa() */ iface->ip_s = talloc_strdup(iface, inet_ntoa(iface->ip)); iface->nmask_s = talloc_strdup(iface, inet_ntoa(iface->nmask)); if (nmask.s_addr != ~0) { iface->bcast_s = talloc_strdup(iface, inet_ntoa(bcast)); } DLIST_ADD_END(*interfaces, iface, struct interface *); DEBUG(2,("added interface ip=%s nmask=%s\n", iface->ip_s, iface->nmask_s)); } /** 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(TALLOC_CTX *mem_ctx, const char *token, struct iface_struct *probed_ifaces, int total_probed, struct interface **local_interfaces) { struct in_addr ip, nmask; char *p; char *address; int i, added=0; ip.s_addr = 0; nmask.s_addr = 0; /* 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(mem_ctx, probed_ifaces[i].ip, probed_ifaces[i].netmask, local_interfaces); added = 1; } } if (added) return; /* maybe it is a DNS name */ p = strchr_m(token,'/'); if (!p) { /* don't try to do dns lookups on wildcard names */ if (strpbrk(token, "*?") != NULL) { return; } ip.s_addr = interpret_addr2(token).s_addr; for (i=0;i<total_probed;i++) { if (ip.s_addr == probed_ifaces[i].ip.s_addr) { add_interface(mem_ctx, probed_ifaces[i].ip, probed_ifaces[i].netmask, local_interfaces); return; } } DEBUG(2,("can't determine netmask for %s\n", token)); return; } address = talloc_strdup(mem_ctx, token); p = strchr_m(address,'/'); /* parse it into an IP address/netmasklength pair */ *p++ = 0; ip.s_addr = interpret_addr2(address).s_addr; if (strlen(p) > 2) { nmask.s_addr = interpret_addr2(p).s_addr; } 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_v4(ip, probed_ifaces[i].ip, nmask)) { add_interface(mem_ctx, probed_ifaces[i].ip, nmask, local_interfaces); talloc_free(address); return; } } DEBUG(2,("Can't determine ip for broadcast address %s\n", address)); talloc_free(address); return; } add_interface(mem_ctx, ip, nmask, local_interfaces); talloc_free(address); } /** load the list of network interfaces **/ void load_interfaces(TALLOC_CTX *mem_ctx, const char **interfaces, struct interface **local_interfaces) { const char **ptr = interfaces; int i; struct iface_struct ifaces[MAX_INTERFACES]; struct in_addr loopback_ip; int total_probed; *local_interfaces = NULL; loopback_ip = interpret_addr2("127.0.0.1"); /* probe the kernel for interfaces */ total_probed = get_interfaces(ifaces, MAX_INTERFACES); /* if we don't have a interfaces line then use all 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")); } for (i=0;i<total_probed;i++) { if (ifaces[i].ip.s_addr != loopback_ip.s_addr) { add_interface(mem_ctx, ifaces[i].ip, ifaces[i].netmask, local_interfaces); } } } while (ptr && *ptr) { interpret_interface(mem_ctx, *ptr, ifaces, total_probed, local_interfaces); ptr++; } if (!*local_interfaces) { DEBUG(0,("WARNING: no network interfaces found\n")); } } /** how many interfaces do we have **/ int iface_count(struct interface *ifaces) { int ret = 0; struct interface *i; for (i=ifaces;i;i=i->next) ret++; return ret; } /** return IP of the Nth interface **/ const char *iface_n_ip(struct interface *ifaces, int n) { struct interface *i; for (i=ifaces;i && n;i=i->next) n--; if (i) { return i->ip_s; } return NULL; } /** return bcast of the Nth interface **/ const char *iface_n_bcast(struct interface *ifaces, int n) { struct interface *i; for (i=ifaces;i && n;i=i->next) n--; if (i) { return i->bcast_s; } return NULL; } /** return netmask of the Nth interface **/ const char *iface_n_netmask(struct interface *ifaces, int n) { struct interface *i; for (i=ifaces;i && n;i=i->next) n--; if (i) { return i->nmask_s; } return NULL; } /** return the local IP address that best matches a destination IP, or our first interface if none match */ const char *iface_best_ip(struct interface *ifaces, const char *dest) { struct interface *iface; struct in_addr ip; ip.s_addr = interpret_addr(dest); iface = iface_find(ifaces, ip, true); if (iface) { return iface->ip_s; } return iface_n_ip(ifaces, 0); } /** return true if an IP is one one of our local networks */ bool iface_is_local(struct interface *ifaces, const char *dest) { struct in_addr ip; ip.s_addr = interpret_addr(dest); if (iface_find(ifaces, ip, true)) { return true; } return false; } /** return true if a IP matches a IP/netmask pair */ bool iface_same_net(const char *ip1, const char *ip2, const char *netmask) { return same_net_v4(interpret_addr2(ip1), interpret_addr2(ip2), interpret_addr2(netmask)); }