/* dnsmasq is Copyright (c) 2000-2013 Simon Kelley 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; version 2 dated June, 1991, or (at your option) version 3 dated 29 June, 2007. 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 . */ #include "dnsmasq.h" #ifdef HAVE_DHCP void dhcp_common_init(void) { /* These each hold a DHCP option max size 255 and get a terminating zero added */ daemon->dhcp_buff = safe_malloc(256); daemon->dhcp_buff2 = safe_malloc(256); daemon->dhcp_buff3 = safe_malloc(256); /* dhcp_packet is used by v4 and v6, outpacket only by v6 sizeof(struct dhcp_packet) is as good an initial size as any, even for v6 */ expand_buf(&daemon->dhcp_packet, sizeof(struct dhcp_packet)); #ifdef HAVE_DHCP6 if (daemon->dhcp6) expand_buf(&daemon->outpacket, sizeof(struct dhcp_packet)); #endif } ssize_t recv_dhcp_packet(int fd, struct msghdr *msg) { ssize_t sz; while (1) { msg->msg_flags = 0; while ((sz = recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC)) == -1 && errno == EINTR); if (sz == -1) return -1; if (!(msg->msg_flags & MSG_TRUNC)) break; /* Very new Linux kernels return the actual size needed, older ones always return truncated size */ if ((size_t)sz == msg->msg_iov->iov_len) { if (!expand_buf(msg->msg_iov, sz + 100)) return -1; } else { expand_buf(msg->msg_iov, sz); break; } } while ((sz = recvmsg(fd, msg, 0)) == -1 && errno == EINTR); return (msg->msg_flags & MSG_TRUNC) ? -1 : sz; } struct dhcp_netid *run_tag_if(struct dhcp_netid *tags) { struct tag_if *exprs; struct dhcp_netid_list *list; for (exprs = daemon->tag_if; exprs; exprs = exprs->next) if (match_netid(exprs->tag, tags, 1)) for (list = exprs->set; list; list = list->next) { list->list->next = tags; tags = list->list; } return tags; } struct dhcp_netid *option_filter(struct dhcp_netid *tags, struct dhcp_netid *context_tags, struct dhcp_opt *opts) { struct dhcp_netid *tagif = run_tag_if(tags); struct dhcp_opt *opt; struct dhcp_opt *tmp; /* flag options which are valid with the current tag set (sans context tags) */ for (opt = opts; opt; opt = opt->next) { opt->flags &= ~DHOPT_TAGOK; if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925)) && match_netid(opt->netid, tagif, 0)) opt->flags |= DHOPT_TAGOK; } /* now flag options which are valid, including the context tags, otherwise valid options are inhibited if we found a higher priority one above */ if (context_tags) { struct dhcp_netid *last_tag; for (last_tag = context_tags; last_tag->next; last_tag = last_tag->next); last_tag->next = tags; tagif = run_tag_if(context_tags); /* reset stuff with tag:! which now matches. */ for (opt = opts; opt; opt = opt->next) if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925)) && (opt->flags & DHOPT_TAGOK) && !match_netid(opt->netid, tagif, 0)) opt->flags &= ~DHOPT_TAGOK; for (opt = opts; opt; opt = opt->next) if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925 | DHOPT_TAGOK)) && match_netid(opt->netid, tagif, 0)) { struct dhcp_opt *tmp; for (tmp = opts; tmp; tmp = tmp->next) if (tmp->opt == opt->opt && opt->netid && (tmp->flags & DHOPT_TAGOK)) break; if (!tmp) opt->flags |= DHOPT_TAGOK; } } /* now flag untagged options which are not overridden by tagged ones */ for (opt = opts; opt; opt = opt->next) if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925 | DHOPT_TAGOK)) && !opt->netid) { for (tmp = opts; tmp; tmp = tmp->next) if (tmp->opt == opt->opt && (tmp->flags & DHOPT_TAGOK)) break; if (!tmp) opt->flags |= DHOPT_TAGOK; else if (!tmp->netid) my_syslog(MS_DHCP | LOG_WARNING, _("Ignoring duplicate dhcp-option %d"), tmp->opt); } /* Finally, eliminate duplicate options later in the chain, and therefore earlier in the config file. */ for (opt = opts; opt; opt = opt->next) if (opt->flags & DHOPT_TAGOK) for (tmp = opt->next; tmp; tmp = tmp->next) if (tmp->opt == opt->opt) tmp->flags &= ~DHOPT_TAGOK; return tagif; } /* Is every member of check matched by a member of pool? If tagnotneeded, untagged is OK */ int match_netid(struct dhcp_netid *check, struct dhcp_netid *pool, int tagnotneeded) { struct dhcp_netid *tmp1; if (!check && !tagnotneeded) return 0; for (; check; check = check->next) { /* '#' for not is for backwards compat. */ if (check->net[0] != '!' && check->net[0] != '#') { for (tmp1 = pool; tmp1; tmp1 = tmp1->next) if (strcmp(check->net, tmp1->net) == 0) break; if (!tmp1) return 0; } else for (tmp1 = pool; tmp1; tmp1 = tmp1->next) if (strcmp((check->net)+1, tmp1->net) == 0) return 0; } return 1; } /* return domain or NULL if none. */ char *strip_hostname(char *hostname) { char *dot = strchr(hostname, '.'); if (!dot) return NULL; *dot = 0; /* truncate */ if (strlen(dot+1) != 0) return dot+1; return NULL; } void log_tags(struct dhcp_netid *netid, u32 xid) { if (netid && option_bool(OPT_LOG_OPTS)) { char *s = daemon->namebuff; for (*s = 0; netid; netid = netid->next) { /* kill dupes. */ struct dhcp_netid *n; for (n = netid->next; n; n = n->next) if (strcmp(netid->net, n->net) == 0) break; if (!n) { strncat (s, netid->net, (MAXDNAME-1) - strlen(s)); if (netid->next) strncat (s, ", ", (MAXDNAME-1) - strlen(s)); } } my_syslog(MS_DHCP | LOG_INFO, _("%u tags: %s"), xid, s); } } int match_bytes(struct dhcp_opt *o, unsigned char *p, int len) { int i; if (o->len > len) return 0; if (o->len == 0) return 1; if (o->flags & DHOPT_HEX) { if (memcmp_masked(o->val, p, o->len, o->u.wildcard_mask)) return 1; } else for (i = 0; i <= (len - o->len); ) { if (memcmp(o->val, p + i, o->len) == 0) return 1; if (o->flags & DHOPT_STRING) i++; else i += o->len; } return 0; } void dhcp_update_configs(struct dhcp_config *configs) { /* Some people like to keep all static IP addresses in /etc/hosts. This goes through /etc/hosts and sets static addresses for any DHCP config records which don't have an address and whose name matches. We take care to maintain the invariant that any IP address can appear in at most one dhcp-host. Since /etc/hosts can be re-read by SIGHUP, restore the status-quo ante first. */ struct dhcp_config *config, *conf_tmp; struct crec *crec; int prot = AF_INET; for (config = configs; config; config = config->next) if (config->flags & CONFIG_ADDR_HOSTS) config->flags &= ~(CONFIG_ADDR | CONFIG_ADDR6 | CONFIG_ADDR_HOSTS); #ifdef HAVE_DHCP6 again: #endif if (daemon->port != 0) for (config = configs; config; config = config->next) { int conflags = CONFIG_ADDR; int cacheflags = F_IPV4; #ifdef HAVE_DHCP6 if (prot == AF_INET6) { conflags = CONFIG_ADDR6; cacheflags = F_IPV6; } #endif if (!(config->flags & conflags) && (config->flags & CONFIG_NAME) && (crec = cache_find_by_name(NULL, config->hostname, 0, cacheflags)) && (crec->flags & F_HOSTS)) { if (cache_find_by_name(crec, config->hostname, 0, cacheflags)) { /* use primary (first) address */ while (crec && !(crec->flags & F_REVERSE)) crec = cache_find_by_name(crec, config->hostname, 0, cacheflags); if (!crec) continue; /* should be never */ inet_ntop(prot, &crec->addr.addr, daemon->addrbuff, ADDRSTRLEN); my_syslog(MS_DHCP | LOG_WARNING, _("%s has more than one address in hostsfile, using %s for DHCP"), config->hostname, daemon->addrbuff); } if (prot == AF_INET && (!(conf_tmp = config_find_by_address(configs, crec->addr.addr.addr.addr4)) || conf_tmp == config)) { config->addr = crec->addr.addr.addr.addr4; config->flags |= CONFIG_ADDR | CONFIG_ADDR_HOSTS; continue; } #ifdef HAVE_DHCP6 if (prot == AF_INET6 && (!(conf_tmp = config_find_by_address6(configs, &crec->addr.addr.addr.addr6, 128, 0)) || conf_tmp == config)) { memcpy(&config->addr6, &crec->addr.addr.addr.addr6, IN6ADDRSZ); config->flags |= CONFIG_ADDR6 | CONFIG_ADDR_HOSTS; continue; } #endif inet_ntop(prot, &crec->addr.addr, daemon->addrbuff, ADDRSTRLEN); my_syslog(MS_DHCP | LOG_WARNING, _("duplicate IP address %s (%s) in dhcp-config directive"), daemon->addrbuff, config->hostname); } } #ifdef HAVE_DHCP6 if (prot == AF_INET) { prot = AF_INET6; goto again; } #endif } #ifdef HAVE_LINUX_NETWORK void bindtodevice(int fd) { /* If we are doing DHCP on exactly one interface, and running linux, do SO_BINDTODEVICE to that device. This is for the use case of (eg) OpenStack, which runs a new dnsmasq instance for each VLAN interface it creates. Without the BINDTODEVICE, individual processes don't always see the packets they should. SO_BINDTODEVICE is only available Linux. */ struct irec *iface, *found; for (found = NULL, iface = daemon->interfaces; iface; iface = iface->next) if (iface->dhcp_ok) { if (!found) found = iface; else if (strcmp(found->name, iface->name) != 0) { /* more than one. */ found = NULL; break; } } if (found) { struct ifreq ifr; strcpy(ifr.ifr_name, found->name); /* only allowed by root. */ if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr)) == -1 && errno != EPERM) die(_("failed to set SO_BINDTODEVICE on DHCP socket: %s"), NULL, EC_BADNET); } } #endif static const struct opttab_t { char *name; u16 val, size; } opttab[] = { { "netmask", 1, OT_ADDR_LIST }, { "time-offset", 2, 4 }, { "router", 3, OT_ADDR_LIST }, { "dns-server", 6, OT_ADDR_LIST }, { "log-server", 7, OT_ADDR_LIST }, { "lpr-server", 9, OT_ADDR_LIST }, { "hostname", 12, OT_INTERNAL | OT_NAME }, { "boot-file-size", 13, 2 | OT_DEC }, { "domain-name", 15, OT_NAME }, { "swap-server", 16, OT_ADDR_LIST }, { "root-path", 17, OT_NAME }, { "extension-path", 18, OT_NAME }, { "ip-forward-enable", 19, 1 }, { "non-local-source-routing", 20, 1 }, { "policy-filter", 21, OT_ADDR_LIST }, { "max-datagram-reassembly", 22, 2 | OT_DEC }, { "default-ttl", 23, 1 | OT_DEC }, { "mtu", 26, 2 | OT_DEC }, { "all-subnets-local", 27, 1 }, { "broadcast", 28, OT_INTERNAL | OT_ADDR_LIST }, { "router-discovery", 31, 1 }, { "router-solicitation", 32, OT_ADDR_LIST }, { "static-route", 33, OT_ADDR_LIST }, { "trailer-encapsulation", 34, 1 }, { "arp-timeout", 35, 4 | OT_DEC }, { "ethernet-encap", 36, 1 }, { "tcp-ttl", 37, 1 }, { "tcp-keepalive", 38, 4 | OT_DEC }, { "nis-domain", 40, OT_NAME }, { "nis-server", 41, OT_ADDR_LIST }, { "ntp-server", 42, OT_ADDR_LIST }, { "vendor-encap", 43, OT_INTERNAL }, { "netbios-ns", 44, OT_ADDR_LIST }, { "netbios-dd", 45, OT_ADDR_LIST }, { "netbios-nodetype", 46, 1 }, { "netbios-scope", 47, 0 }, { "x-windows-fs", 48, OT_ADDR_LIST }, { "x-windows-dm", 49, OT_ADDR_LIST }, { "requested-address", 50, OT_INTERNAL | OT_ADDR_LIST }, { "lease-time", 51, OT_INTERNAL | OT_TIME }, { "option-overload", 52, OT_INTERNAL }, { "message-type", 53, OT_INTERNAL | OT_DEC }, { "server-identifier", 54, OT_INTERNAL | OT_ADDR_LIST }, { "parameter-request", 55, OT_INTERNAL }, { "message", 56, OT_INTERNAL }, { "max-message-size", 57, OT_INTERNAL }, { "T1", 58, OT_INTERNAL | OT_TIME}, { "T2", 59, OT_INTERNAL | OT_TIME}, { "vendor-class", 60, 0 }, { "client-id", 61, OT_INTERNAL }, { "nis+-domain", 64, OT_NAME }, { "nis+-server", 65, OT_ADDR_LIST }, { "tftp-server", 66, OT_NAME }, { "bootfile-name", 67, OT_NAME }, { "mobile-ip-home", 68, OT_ADDR_LIST }, { "smtp-server", 69, OT_ADDR_LIST }, { "pop3-server", 70, OT_ADDR_LIST }, { "nntp-server", 71, OT_ADDR_LIST }, { "irc-server", 74, OT_ADDR_LIST }, { "user-class", 77, 0 }, { "FQDN", 81, OT_INTERNAL }, { "agent-id", 82, OT_INTERNAL }, { "client-arch", 93, 2 | OT_DEC }, { "client-interface-id", 94, 0 }, { "client-machine-id", 97, 0 }, { "subnet-select", 118, OT_INTERNAL }, { "domain-search", 119, OT_RFC1035_NAME }, { "sip-server", 120, 0 }, { "classless-static-route", 121, 0 }, { "vendor-id-encap", 125, 0 }, { "server-ip-address", 255, OT_ADDR_LIST }, /* special, internal only, sets siaddr */ { NULL, 0, 0 } }; #ifdef HAVE_DHCP6 static const struct opttab_t opttab6[] = { { "client-id", 1, OT_INTERNAL }, { "server-id", 2, OT_INTERNAL }, { "ia-na", 3, OT_INTERNAL }, { "ia-ta", 4, OT_INTERNAL }, { "iaaddr", 5, OT_INTERNAL }, { "oro", 6, OT_INTERNAL }, { "preference", 7, OT_INTERNAL | OT_DEC }, { "unicast", 12, OT_INTERNAL }, { "status", 13, OT_INTERNAL }, { "rapid-commit", 14, OT_INTERNAL }, { "user-class", 15, OT_INTERNAL | OT_CSTRING }, { "vendor-class", 16, OT_INTERNAL | OT_CSTRING }, { "vendor-opts", 17, OT_INTERNAL }, { "sip-server-domain", 21, OT_RFC1035_NAME }, { "sip-server", 22, OT_ADDR_LIST }, { "dns-server", 23, OT_ADDR_LIST }, { "domain-search", 24, OT_RFC1035_NAME }, { "nis-server", 27, OT_ADDR_LIST }, { "nis+-server", 28, OT_ADDR_LIST }, { "nis-domain", 29, OT_RFC1035_NAME }, { "nis+-domain", 30, OT_RFC1035_NAME }, { "sntp-server", 31, OT_ADDR_LIST }, { "information-refresh-time", 32, OT_TIME }, { "FQDN", 39, OT_INTERNAL | OT_RFC1035_NAME }, { "ntp-server", 56, OT_ADDR_LIST }, { "bootfile-url", 59, OT_NAME }, { "bootfile-param", 60, OT_CSTRING }, { NULL, 0, 0 } }; #endif void display_opts(void) { int i; printf(_("Known DHCP options:\n")); for (i = 0; opttab[i].name; i++) if (!(opttab[i].size & OT_INTERNAL)) printf("%3d %s\n", opttab[i].val, opttab[i].name); } #ifdef HAVE_DHCP6 void display_opts6(void) { int i; printf(_("Known DHCPv6 options:\n")); for (i = 0; opttab6[i].name; i++) if (!(opttab6[i].size & OT_INTERNAL)) printf("%3d %s\n", opttab6[i].val, opttab6[i].name); } #endif u16 lookup_dhcp_opt(int prot, char *name) { const struct opttab_t *t; int i; #ifdef HAVE_DHCP6 if (prot == AF_INET6) t = opttab6; else #endif t = opttab; for (i = 0; t[i].name; i++) if (strcasecmp(t[i].name, name) == 0) return t[i].val; return 0; } u16 lookup_dhcp_len(int prot, u16 val) { const struct opttab_t *t; int i; #ifdef HAVE_DHCP6 if (prot == AF_INET6) t = opttab6; else #endif t = opttab; for (i = 0; t[i].name; i++) if (val == t[i].val) return t[i].size & ~OT_DEC; return 0; } char *option_string(int prot, unsigned int opt, unsigned char *val, int opt_len, char *buf, int buf_len) { int o, i, j, nodecode = 0; const struct opttab_t *ot = opttab; #ifdef HAVE_DHCP6 if (prot == AF_INET6) ot = opttab6; #endif for (o = 0; ot[o].name; o++) if (ot[o].val == opt) { if (buf) { memset(buf, 0, buf_len); if (ot[o].size & OT_ADDR_LIST) { struct all_addr addr; int addr_len = INADDRSZ; #ifdef HAVE_DHCP6 if (prot == AF_INET6) addr_len = IN6ADDRSZ; #endif for (buf[0]= 0, i = 0; i <= opt_len - addr_len; i += addr_len) { if (i != 0) strncat(buf, ", ", buf_len - strlen(buf)); /* align */ memcpy(&addr, &val[i], addr_len); inet_ntop(prot, &val[i], daemon->addrbuff, ADDRSTRLEN); strncat(buf, daemon->addrbuff, buf_len - strlen(buf)); } } else if (ot[o].size & OT_NAME) for (i = 0, j = 0; i < opt_len && j < buf_len ; i++) { char c = val[i]; if (isprint((int)c)) buf[j++] = c; } #ifdef HAVE_DHCP6 /* We don't handle compressed rfc1035 names, so no good in IPv4 land */ else if ((ot[o].size & OT_RFC1035_NAME) && prot == AF_INET6) { i = 0, j = 0; while (i < opt_len && val[i] != 0) { int k, l = i + val[i] + 1; for (k = i + 1; k < opt_len && k < l && j < buf_len ; k++) { char c = val[k]; if (isprint((int)c)) buf[j++] = c; } i = l; if (val[i] != 0 && j < buf_len) buf[j++] = '.'; } } else if ((ot[o].size & OT_CSTRING)) { int k, len; unsigned char *p; i = 0, j = 0; while (1) { p = &val[i]; GETSHORT(len, p); for (k = 0; k < len && j < buf_len; k++) { char c = *p++; if (isprint((int)c)) buf[j++] = c; } i += len +2; if (i >= opt_len) break; if (j < buf_len) buf[j++] = ','; } } #endif else if ((ot[o].size & (OT_DEC | OT_TIME)) && opt_len != 0) { unsigned int dec = 0; for (i = 0; i < opt_len; i++) dec = (dec << 8) | val[i]; if (ot[o].size & OT_TIME) prettyprint_time(buf, dec); else sprintf(buf, "%u", dec); } else nodecode = 1; } break; } if (opt_len != 0 && buf && (!ot[o].name || nodecode)) { int trunc = 0; if (opt_len > 14) { trunc = 1; opt_len = 14; } print_mac(buf, val, opt_len); if (trunc) strncat(buf, "...", buf_len - strlen(buf)); } return ot[o].name ? ot[o].name : ""; } void log_context(int family, struct dhcp_context *context) { /* Cannot use dhcp_buff* for RA contexts */ void *start = &context->start; void *end = &context->end; char *template = "", *p = daemon->namebuff; *p = 0; #ifdef HAVE_DHCP6 if (family == AF_INET6) { struct in6_addr subnet = context->start6; if (!(context->flags & CONTEXT_TEMPLATE)) setaddr6part(&subnet, 0); inet_ntop(AF_INET6, &subnet, daemon->addrbuff, ADDRSTRLEN); start = &context->start6; end = &context->end6; } #endif if (family != AF_INET && (context->flags & CONTEXT_DEPRECATE)) strcpy(daemon->namebuff, _(", prefix deprecated")); else { p += sprintf(p, _(", lease time ")); prettyprint_time(p, context->lease_time); p += strlen(p); } #ifdef HAVE_DHCP6 if (context->flags & CONTEXT_CONSTRUCTED) { char ifrn_name[IFNAMSIZ]; template = p; p += sprintf(p, ", "); if (indextoname(daemon->doing_dhcp6 ? daemon->dhcp6fd : daemon->icmp6fd, context->if_index, ifrn_name)) sprintf(p, "constructed for %s", ifrn_name); } else if (context->flags & CONTEXT_TEMPLATE) { template = p; p += sprintf(p, ", "); sprintf(p, "template for %s", context->template_interface); } #endif if ((context->flags & CONTEXT_DHCP) || family == AF_INET) { inet_ntop(family, start, daemon->dhcp_buff, 256); inet_ntop(family, end, daemon->dhcp_buff3, 256); my_syslog(MS_DHCP | LOG_INFO, (context->flags & CONTEXT_RA_STATELESS) ? _("%s stateless on %s%.0s%.0s%s") : (context->flags & CONTEXT_STATIC) ? _("%s, static leases only on %.0s%s%s%.0s") : (context->flags & CONTEXT_PROXY) ? _("%s, proxy on subnet %.0s%s%.0s%.0s") : _("%s, IP range %s -- %s%s%.0s"), (family != AF_INET) ? "DHCPv6" : "DHCP", daemon->dhcp_buff, daemon->dhcp_buff3, daemon->namebuff, template); } #ifdef HAVE_DHCP6 if (context->flags & CONTEXT_RA_NAME) my_syslog(MS_DHCP | LOG_INFO, _("DHCPv4-derived IPv6 names on %s%s"), daemon->addrbuff, template); if ((context->flags & CONTEXT_RA) || (option_bool(OPT_RA) && (context->flags & CONTEXT_DHCP) && family == AF_INET6)) my_syslog(MS_DHCP | LOG_INFO, _("router advertisement on %s%s"), daemon->addrbuff, template); #endif } #endif