| /* dnsmasq is Copyright (c) 2000-2006 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. |
| |
| 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. |
| */ |
| |
| #include "dnsmasq.h" |
| |
| struct iface_param { |
| struct in_addr relay, primary; |
| struct dhcp_context *current; |
| int ind; |
| }; |
| |
| static int complete_context(struct daemon *daemon, struct in_addr local, int if_index, |
| struct in_addr netmask, struct in_addr broadcast, void *vparam); |
| |
| void dhcp_init(struct daemon *daemon) |
| { |
| int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); |
| struct sockaddr_in saddr; |
| int oneopt = 1; |
| struct dhcp_config *configs, *cp; |
| |
| if (fd == -1) |
| die (_("cannot create DHCP socket : %s"), NULL); |
| |
| if (!fix_fd(fd) || |
| #if defined(HAVE_LINUX_NETWORK) |
| setsockopt(fd, SOL_IP, IP_PKTINFO, &oneopt, sizeof(oneopt)) == -1 || |
| #elif defined(IP_RECVIF) |
| setsockopt(fd, IPPROTO_IP, IP_RECVIF, &oneopt, sizeof(oneopt)) == -1 || |
| #endif |
| setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &oneopt, sizeof(oneopt)) == -1) |
| die(_("failed to set options on DHCP socket: %s"), NULL); |
| |
| /* When bind-interfaces is set, there might be more than one dnmsasq |
| instance binding port 67. That's Ok if they serve different networks. |
| Need to set REUSEADDR to make this posible. */ |
| if ((daemon->options & OPT_NOWILD) && |
| setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &oneopt, sizeof(oneopt)) == -1) |
| die(_("failed to set SO_REUSEADDR on DHCP socket: %s"), NULL); |
| |
| memset(&saddr, 0, sizeof(saddr)); |
| saddr.sin_family = AF_INET; |
| saddr.sin_port = htons(DHCP_SERVER_PORT); |
| saddr.sin_addr.s_addr = INADDR_ANY; |
| #ifdef HAVE_SOCKADDR_SA_LEN |
| saddr.sin_len = sizeof(struct sockaddr_in); |
| #endif |
| |
| if (bind(fd, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in))) |
| die(_("failed to bind DHCP server socket: %s"), NULL); |
| |
| daemon->dhcpfd = fd; |
| |
| #ifndef HAVE_LINUX_NETWORK |
| /* When we're not using capabilities, we need to do this here before |
| we drop root. Also, set buffer size small, to avoid wasting |
| kernel buffers */ |
| |
| if (daemon->options & OPT_NO_PING) |
| daemon->dhcp_icmp_fd = -1; |
| else if ((daemon->dhcp_icmp_fd = make_icmp_sock()) == -1 || |
| setsockopt(daemon->dhcp_icmp_fd, SOL_SOCKET, SO_RCVBUF, &oneopt, sizeof(oneopt)) == -1 ) |
| die(_("cannot create ICMP raw socket: %s."), NULL); |
| |
| /* Make BPF raw send socket */ |
| init_bpf(daemon); |
| #endif |
| |
| /* If the same IP appears in more than one host config, then DISCOVER |
| for one of the hosts will get the address, but REQUEST will be NAKed, |
| since the address is reserved by the other one -> protocol loop. */ |
| for (configs = daemon->dhcp_conf; configs; configs = configs->next) |
| for (cp = configs->next; cp; cp = cp->next) |
| if ((configs->flags & cp->flags & CONFIG_ADDR) && configs->addr.s_addr == cp->addr.s_addr) |
| die(_("duplicate IP address %s in dhcp-config directive."), inet_ntoa(cp->addr)); |
| |
| daemon->dhcp_packet.iov_len = sizeof(struct dhcp_packet); |
| daemon->dhcp_packet.iov_base = safe_malloc(daemon->dhcp_packet.iov_len); |
| /* These two 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->ping_results = NULL; |
| } |
| |
| void dhcp_packet(struct daemon *daemon, time_t now) |
| { |
| struct dhcp_packet *mess; |
| struct dhcp_context *context; |
| struct iname *tmp; |
| struct ifreq ifr; |
| struct msghdr msg; |
| struct sockaddr_in dest; |
| struct cmsghdr *cmptr; |
| struct iovec iov; |
| ssize_t sz; |
| int iface_index = 0, unicast_dest = 0; |
| struct in_addr iface_addr; |
| struct iface_param parm; |
| |
| union { |
| struct cmsghdr align; /* this ensures alignment */ |
| #ifdef HAVE_LINUX_NETWORK |
| char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
| #else |
| char control[CMSG_SPACE(sizeof(struct sockaddr_dl))]; |
| #endif |
| } control_u; |
| |
| msg.msg_control = control_u.control; |
| msg.msg_controllen = sizeof(control_u); |
| msg.msg_name = NULL; |
| msg.msg_namelen = 0; |
| msg.msg_iov = &daemon->dhcp_packet; |
| msg.msg_iovlen = 1; |
| |
| do |
| { |
| msg.msg_flags = 0; |
| while ((sz = recvmsg(daemon->dhcpfd, &msg, MSG_PEEK)) == -1 && errno == EINTR); |
| } |
| while (sz != -1 && (msg.msg_flags & MSG_TRUNC) && |
| expand_buf(&daemon->dhcp_packet, daemon->dhcp_packet.iov_len + 100)); |
| |
| /* expand_buf may have moved buffer */ |
| mess = daemon->dhcp_packet.iov_base; |
| msg.msg_controllen = sizeof(control_u); |
| msg.msg_flags = 0; |
| msg.msg_name = &dest; |
| msg.msg_namelen = sizeof(dest); |
| |
| while ((sz = recvmsg(daemon->dhcpfd, &msg, 0)) && errno == EINTR); |
| |
| if ((msg.msg_flags & MSG_TRUNC) || |
| sz < (ssize_t)(sizeof(*mess) - sizeof(mess->options))) |
| return; |
| |
| #if defined (HAVE_LINUX_NETWORK) |
| if (msg.msg_controllen < sizeof(struct cmsghdr)) |
| return; |
| for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) |
| { |
| iface_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
| if (((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_addr.s_addr != INADDR_BROADCAST) |
| unicast_dest = 1; |
| } |
| |
| if (!(ifr.ifr_ifindex = iface_index) || |
| ioctl(daemon->dhcpfd, SIOCGIFNAME, &ifr) == -1) |
| return; |
| |
| #elif defined(IP_RECVIF) |
| if (msg.msg_controllen < sizeof(struct cmsghdr)) |
| return; |
| for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
| iface_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; |
| |
| if (!iface_index || !if_indextoname(iface_index, ifr.ifr_name)) |
| return; |
| |
| #else |
| { |
| struct iname *name; |
| for (name = daemon->if_names; name->isloop; name = name->next); |
| strcpy(ifr.ifr_name, name->name); |
| iface_index = if_nametoindex(name->name); |
| } |
| #endif |
| |
| ifr.ifr_addr.sa_family = AF_INET; |
| if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) < 0 ) |
| return; |
| iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; |
| |
| for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next) |
| if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
| return; |
| |
| if (!iface_check(daemon, AF_INET, (struct all_addr *)&iface_addr, ifr.ifr_name)) |
| return; |
| |
| /* unlinked contexts are marked by context->current == context */ |
| for (context = daemon->dhcp; context; context = context->next) |
| context->current = context; |
| |
| parm.relay = mess->giaddr; |
| parm.primary = iface_addr; |
| parm.current = NULL; |
| parm.ind = iface_index; |
| |
| if (!iface_enumerate(daemon, &parm, complete_context, NULL)) |
| return; |
| lease_prune(NULL, now); /* lose any expired leases */ |
| iov.iov_len = dhcp_reply(daemon, parm.current, ifr.ifr_name, (size_t)sz, now, unicast_dest); |
| lease_update_file(daemon, now); |
| lease_update_dns(daemon); |
| lease_collect(daemon); |
| |
| if (iov.iov_len == 0) |
| return; |
| |
| msg.msg_name = &dest; |
| msg.msg_namelen = sizeof(dest); |
| msg.msg_control = NULL; |
| msg.msg_controllen = 0; |
| msg.msg_iov = &iov; |
| iov.iov_base = daemon->dhcp_packet.iov_base; |
| |
| /* packet buffer may have moved */ |
| mess = daemon->dhcp_packet.iov_base; |
| |
| #ifdef HAVE_SOCKADDR_SA_LEN |
| dest.sin_len = sizeof(struct sockaddr_in); |
| #endif |
| |
| if (mess->giaddr.s_addr) |
| { |
| /* Send to BOOTP relay */ |
| dest.sin_port = htons(DHCP_SERVER_PORT); |
| dest.sin_addr = mess->giaddr; |
| } |
| else if (mess->ciaddr.s_addr) |
| { |
| /* If the client's idea of its own address tallys with |
| the source address in the request packet, we believe the |
| source port too, and send back to that. */ |
| if (dest.sin_addr.s_addr != mess->ciaddr.s_addr || !dest.sin_port) |
| { |
| dest.sin_port = htons(DHCP_CLIENT_PORT); |
| dest.sin_addr = mess->ciaddr; |
| } |
| } |
| #ifdef HAVE_LINUX_NETWORK |
| else if ((ntohs(mess->flags) & 0x8000) || mess->hlen == 0 || |
| mess->hlen > sizeof(ifr.ifr_addr.sa_data) || mess->htype == 0) |
| { |
| /* broadcast to 255.255.255.255 (or mac address invalid) */ |
| struct in_pktinfo *pkt; |
| msg.msg_control = control_u.control; |
| msg.msg_controllen = sizeof(control_u); |
| cmptr = CMSG_FIRSTHDR(&msg); |
| dest.sin_addr.s_addr = INADDR_BROADCAST; |
| dest.sin_port = htons(DHCP_CLIENT_PORT); |
| pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
| pkt->ipi_ifindex = iface_index; |
| pkt->ipi_spec_dst.s_addr = 0; |
| msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); |
| cmptr->cmsg_level = SOL_IP; |
| cmptr->cmsg_type = IP_PKTINFO; |
| } |
| else |
| { |
| /* unicast to unconfigured client. Inject mac address direct into ARP cache. |
| struct sockaddr limits size to 14 bytes. */ |
| struct arpreq req; |
| dest.sin_addr = mess->yiaddr; |
| dest.sin_port = htons(DHCP_CLIENT_PORT); |
| *((struct sockaddr_in *)&req.arp_pa) = dest; |
| req.arp_ha.sa_family = mess->htype; |
| memcpy(req.arp_ha.sa_data, mess->chaddr, mess->hlen); |
| strncpy(req.arp_dev, ifr.ifr_name, 16); |
| req.arp_flags = ATF_COM; |
| ioctl(daemon->dhcpfd, SIOCSARP, &req); |
| } |
| #else |
| else |
| { |
| send_via_bpf(daemon, mess, iov.iov_len, iface_addr, &ifr); |
| return; |
| } |
| #endif |
| |
| while(sendmsg(daemon->dhcpfd, &msg, 0) == -1 && retry_send()); |
| } |
| |
| /* This is a complex routine: it gets called with each (address,netmask,broadcast) triple |
| of each interface (and any relay address) and does the following things: |
| |
| 1) Discards stuff for interfaces other than the one on which a DHCP packet just arrived. |
| 2) Fills in any netmask and broadcast addresses which have not been explicitly configured. |
| 3) Fills in local (this host) and router (this host or relay) addresses. |
| 4) Links contexts which are valid for hosts directly connected to the arrival interface on ->current. |
| |
| Note that the current chain may be superceded later for configured hosts or those coming via gateways. */ |
| |
| static int complete_context(struct daemon *daemon, struct in_addr local, int if_index, |
| struct in_addr netmask, struct in_addr broadcast, void *vparam) |
| { |
| struct dhcp_context *context; |
| struct iface_param *param = vparam; |
| |
| if (if_index != param->ind) |
| return 1; /* no for us. */ |
| |
| for (context = daemon->dhcp; context; context = context->next) |
| { |
| if (!(context->flags & CONTEXT_NETMASK) && |
| (is_same_net(local, context->start, netmask) || |
| is_same_net(local, context->end, netmask))) |
| { |
| if (context->netmask.s_addr != netmask.s_addr && |
| !(is_same_net(local, context->start, netmask) && |
| is_same_net(local, context->end, netmask))) |
| { |
| strcpy(daemon->dhcp_buff, inet_ntoa(context->start)); |
| strcpy(daemon->dhcp_buff2, inet_ntoa(context->end)); |
| syslog(LOG_WARNING, _("DHCP range %s -- %s is not consistent with netmask %s"), |
| daemon->dhcp_buff, daemon->dhcp_buff2, inet_ntoa(netmask)); |
| } |
| context->netmask = netmask; |
| } |
| |
| if (context->netmask.s_addr) |
| { |
| if (is_same_net(local, context->start, context->netmask) && |
| is_same_net(local, context->end, context->netmask)) |
| { |
| /* link it onto the current chain if we've not seen it before */ |
| if (context->current == context) |
| { |
| context->router = local; |
| context->local = local; |
| context->current = param->current; |
| param->current = context; |
| } |
| |
| if (!(context->flags & CONTEXT_BRDCAST)) |
| { |
| if (is_same_net(broadcast, context->start, context->netmask)) |
| context->broadcast = broadcast; |
| else |
| context->broadcast.s_addr = context->start.s_addr | ~context->netmask.s_addr; |
| } |
| } |
| else if (param->relay.s_addr && is_same_net(param->relay, context->start, context->netmask)) |
| { |
| context->router = param->relay; |
| context->local = param->primary; |
| /* fill in missing broadcast addresses for relayed ranges */ |
| if (!(context->flags & CONTEXT_BRDCAST)) |
| context->broadcast.s_addr = context->start.s_addr | ~context->netmask.s_addr; |
| } |
| |
| } |
| } |
| |
| return 1; |
| } |
| |
| struct dhcp_context *address_available(struct dhcp_context *context, struct in_addr taddr) |
| { |
| /* Check is an address is OK for this network, check all |
| possible ranges. Make sure that the address isn't in use |
| by the server itself. */ |
| |
| unsigned int start, end, addr = ntohl(taddr.s_addr); |
| struct dhcp_context *tmp; |
| |
| for (tmp = context; tmp; tmp = tmp->current) |
| if (taddr.s_addr == context->router.s_addr) |
| return NULL; |
| |
| for (tmp = context; tmp; tmp = tmp->current) |
| { |
| start = ntohl(tmp->start.s_addr); |
| end = ntohl(tmp->end.s_addr); |
| |
| if (!(tmp->flags & CONTEXT_STATIC) && |
| addr >= start && |
| addr <= end) |
| return tmp; |
| } |
| |
| return NULL; |
| } |
| |
| struct dhcp_context *narrow_context(struct dhcp_context *context, struct in_addr taddr) |
| { |
| /* We start of with a set of possible contexts, all on the current physical interface. |
| These are chained on ->current. |
| Here we have an address, and return the actual context correponding to that |
| address. Note that none may fit, if the address came a dhcp-host and is outside |
| any dhcp-range. In that case we return a static range if possible, or failing that, |
| any context on the correct subnet. (If there's more than one, this is a dodgy |
| configuration: maybe there should be a warning.) */ |
| |
| struct dhcp_context *tmp; |
| |
| if ((tmp = address_available(context, taddr))) |
| return tmp; |
| |
| for (tmp = context; tmp; tmp = tmp->current) |
| if (is_same_net(taddr, tmp->start, tmp->netmask) && |
| (tmp->flags & CONTEXT_STATIC)) |
| return tmp; |
| |
| for (tmp = context; tmp; tmp = tmp->current) |
| if (is_same_net(taddr, tmp->start, tmp->netmask)) |
| return tmp; |
| |
| return NULL; |
| } |
| |
| struct dhcp_config *config_find_by_address(struct dhcp_config *configs, struct in_addr addr) |
| { |
| struct dhcp_config *config; |
| |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr) |
| return config; |
| |
| return NULL; |
| } |
| |
| /* Is every member of check matched by a member of pool? |
| If negonly, match unless there's a negative tag which matches. */ |
| int match_netid(struct dhcp_netid *check, struct dhcp_netid *pool, int negonly) |
| { |
| struct dhcp_netid *tmp1; |
| |
| if (!check && !negonly) |
| return 0; |
| |
| for (; check; check = check->next) |
| { |
| if (check->net[0] != '#') |
| { |
| for (tmp1 = pool; tmp1; tmp1 = tmp1->next) |
| if (strcmp(check->net, tmp1->net) == 0) |
| break; |
| if (!tmp1 || negonly) |
| return 0; |
| } |
| else |
| for (tmp1 = pool; tmp1; tmp1 = tmp1->next) |
| if (strcmp((check->net)+1, tmp1->net) == 0) |
| return 0; |
| } |
| return 1; |
| } |
| |
| int address_allocate(struct dhcp_context *context, struct daemon *daemon, |
| struct in_addr *addrp, unsigned char *hwaddr, int hw_len, |
| struct dhcp_netid *netids, time_t now) |
| { |
| /* Find a free address: exclude anything in use and anything allocated to |
| a particular hwaddr/clientid/hostname in our configuration. |
| Try to return from contexts which match netids first. */ |
| |
| struct in_addr start, addr; |
| struct dhcp_context *c, *d; |
| int i, pass; |
| unsigned int j; |
| |
| /* hash hwaddr */ |
| for (j = 0, i = 0; i < hw_len; i++) |
| j += hwaddr[i] + (hwaddr[i] << 8) + (hwaddr[i] << 16); |
| |
| for (pass = 0; pass <= 1; pass++) |
| for (c = context; c; c = c->current) |
| if (c->flags & CONTEXT_STATIC) |
| continue; |
| else if (!match_netid(c->filter, netids, pass)) |
| continue; |
| else |
| { |
| /* pick a seed based on hwaddr then iterate until we find a free address. */ |
| start.s_addr = addr.s_addr = |
| htonl(ntohl(c->start.s_addr) + |
| ((j + c->addr_epoch) % (1 + ntohl(c->end.s_addr) - ntohl(c->start.s_addr)))); |
| |
| do { |
| /* eliminate addresses in use by the server. */ |
| for (d = context; d; d = d->current) |
| if (addr.s_addr == d->router.s_addr) |
| break; |
| |
| if (!d && |
| !lease_find_by_addr(addr) && |
| !config_find_by_address(daemon->dhcp_conf, addr)) |
| { |
| struct ping_result *r, *victim = NULL; |
| int count, max = (int)(0.6 * (((float)PING_CACHE_TIME)/ |
| ((float)PING_WAIT))); |
| |
| *addrp = addr; |
| |
| if (daemon->options & OPT_NO_PING) |
| return 1; |
| |
| /* check if we failed to ping addr sometime in the last |
| PING_CACHE_TIME seconds. If so, assume the same situation still exists. |
| This avoids problems when a stupid client bangs |
| on us repeatedly. As a final check, if we did more |
| than 60% of the possible ping checks in the last |
| PING_CACHE_TIME, we are in high-load mode, so don't do any more. */ |
| for (count = 0, r = daemon->ping_results; r; r = r->next) |
| if (difftime(now, r->time) > (float)PING_CACHE_TIME) |
| victim = r; /* old record */ |
| else if (++count == max || r->addr.s_addr == addr.s_addr) |
| return 1; |
| |
| if (icmp_ping(daemon, addr)) |
| /* address in use: perturb address selection so that we are |
| less likely to try this address again. */ |
| c->addr_epoch++; |
| else |
| { |
| /* at this point victim may hold an expired record */ |
| if (!victim) |
| { |
| if ((victim = malloc(sizeof(struct ping_result)))) |
| { |
| victim->next = daemon->ping_results; |
| daemon->ping_results = victim; |
| } |
| } |
| |
| /* record that this address is OK for 30s |
| without more ping checks */ |
| if (victim) |
| { |
| victim->addr = addr; |
| victim->time = now; |
| } |
| return 1; |
| } |
| } |
| |
| addr.s_addr = htonl(ntohl(addr.s_addr) + 1); |
| |
| if (addr.s_addr == htonl(ntohl(c->end.s_addr) + 1)) |
| addr = c->start; |
| |
| } while (addr.s_addr != start.s_addr); |
| } |
| return 0; |
| } |
| |
| static int is_addr_in_context(struct dhcp_context *context, struct dhcp_config *config) |
| { |
| if (!context) /* called via find_config() from lease_update_from_configs() */ |
| return 1; |
| if (!(config->flags & CONFIG_ADDR)) |
| return 1; |
| for (; context; context = context->current) |
| if (is_same_net(config->addr, context->start, context->netmask)) |
| return 1; |
| |
| return 0; |
| } |
| |
| |
| struct dhcp_config *find_config(struct dhcp_config *configs, |
| struct dhcp_context *context, |
| unsigned char *clid, int clid_len, |
| unsigned char *hwaddr, int hw_len, |
| int hw_type, char *hostname) |
| { |
| struct dhcp_config *config; |
| |
| if (clid) |
| for (config = configs; config; config = config->next) |
| if (config->flags & CONFIG_CLID) |
| { |
| if (config->clid_len == clid_len && |
| memcmp(config->clid, clid, clid_len) == 0 && |
| is_addr_in_context(context, config)) |
| return config; |
| |
| /* dhcpcd prefixes ASCII client IDs by zero which is wrong, but we try and |
| cope with that here */ |
| if (*clid == 0 && config->clid_len == clid_len-1 && |
| memcmp(config->clid, clid+1, clid_len-1) == 0 && |
| is_addr_in_context(context, config)) |
| return config; |
| } |
| |
| |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_HWADDR) && |
| config->wildcard_mask == 0 && |
| config->hwaddr_len == hw_len && |
| (config->hwaddr_type == hw_type || config->hwaddr_type == 0) && |
| memcmp(config->hwaddr, hwaddr, hw_len) == 0 && |
| is_addr_in_context(context, config)) |
| return config; |
| |
| if (hostname && context) |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_NAME) && |
| hostname_isequal(config->hostname, hostname) && |
| is_addr_in_context(context, config)) |
| return config; |
| |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_HWADDR) && |
| config->wildcard_mask != 0 && |
| config->hwaddr_len == hw_len && |
| (config->hwaddr_type == hw_type || config->hwaddr_type == 0) && |
| is_addr_in_context(context, config) && |
| memcmp_masked(config->hwaddr, hwaddr, hw_len, config->wildcard_mask)) |
| return config; |
| |
| return NULL; |
| } |
| |
| void dhcp_read_ethers(struct daemon *daemon) |
| { |
| FILE *f = fopen(ETHERSFILE, "r"); |
| unsigned int flags; |
| char *buff = daemon->namebuff; |
| char *ip, *cp; |
| struct in_addr addr; |
| unsigned char hwaddr[ETHER_ADDR_LEN]; |
| struct dhcp_config **up, *tmp; |
| struct dhcp_config *config, *configs = daemon->dhcp_conf; |
| int count = 0, lineno = 0; |
| |
| addr.s_addr = 0; /* eliminate warning */ |
| |
| if (!f) |
| { |
| syslog(LOG_ERR, _("failed to read %s:%m"), ETHERSFILE); |
| return; |
| } |
| |
| /* This can be called again on SIGHUP, so remove entries created last time round. */ |
| for (up = &daemon->dhcp_conf, config = configs; config; config = tmp) |
| { |
| tmp = config->next; |
| if (config->flags & CONFIG_FROM_ETHERS) |
| { |
| *up = tmp; |
| /* cannot have a clid */ |
| if (config->flags & CONFIG_NAME) |
| free(config->hostname); |
| free(config); |
| } |
| else |
| up = &config->next; |
| } |
| |
| while (fgets(buff, MAXDNAME, f)) |
| { |
| lineno++; |
| |
| while (strlen(buff) > 0 && isspace(buff[strlen(buff)-1])) |
| buff[strlen(buff)-1] = 0; |
| |
| if ((*buff == '#') || (*buff == '+')) |
| continue; |
| |
| for (ip = buff; *ip && !isspace(*ip); ip++); |
| for(; *ip && isspace(*ip); ip++) |
| *ip = 0; |
| if (!*ip || parse_hex(buff, hwaddr, ETHER_ADDR_LEN, NULL, NULL) != ETHER_ADDR_LEN) |
| { |
| syslog(LOG_ERR, _("bad line at %s line %d"), ETHERSFILE, lineno); |
| continue; |
| } |
| |
| /* check for name or dotted-quad */ |
| for (cp = ip; *cp; cp++) |
| if (!(*cp == '.' || (*cp >='0' && *cp <= '9'))) |
| break; |
| |
| if (!*cp) |
| { |
| if ((addr.s_addr = inet_addr(ip)) == (in_addr_t)-1) |
| { |
| syslog(LOG_ERR, _("bad address at %s line %d"), ETHERSFILE, lineno); |
| continue; |
| } |
| |
| flags = CONFIG_ADDR; |
| |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr) |
| break; |
| } |
| else |
| { |
| if (!canonicalise(ip)) |
| { |
| syslog(LOG_ERR, _("bad name at %s line %d"), ETHERSFILE, lineno); |
| continue; |
| } |
| |
| flags = CONFIG_NAME; |
| |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_NAME) && hostname_isequal(config->hostname, ip)) |
| break; |
| } |
| |
| if (!config) |
| { |
| for (config = configs; config; config = config->next) |
| if ((config->flags & CONFIG_HWADDR) && |
| config->wildcard_mask == 0 && |
| config->hwaddr_len == ETHER_ADDR_LEN && |
| (config->hwaddr_type == ARPHRD_ETHER || config->hwaddr_type == 0) && |
| memcmp(config->hwaddr, hwaddr, ETHER_ADDR_LEN) == 0) |
| break; |
| |
| if (!config) |
| { |
| if (!(config = malloc(sizeof(struct dhcp_config)))) |
| continue; |
| config->flags = CONFIG_FROM_ETHERS; |
| config->wildcard_mask = 0; |
| config->next = configs; |
| configs = config; |
| } |
| |
| config->flags |= flags; |
| |
| if (flags & CONFIG_NAME) |
| { |
| if ((config->hostname = malloc(strlen(ip)+1))) |
| strcpy(config->hostname, ip); |
| else |
| config->flags &= ~CONFIG_NAME; |
| } |
| |
| if (flags & CONFIG_ADDR) |
| config->addr = addr; |
| } |
| |
| config->flags |= CONFIG_HWADDR | CONFIG_NOCLID; |
| memcpy(config->hwaddr, hwaddr, ETHER_ADDR_LEN); |
| config->hwaddr_len = ETHER_ADDR_LEN; |
| config->hwaddr_type = ARPHRD_ETHER; |
| count++; |
| } |
| |
| fclose(f); |
| |
| syslog(LOG_INFO, _("read %s - %d addresses"), ETHERSFILE, count); |
| |
| daemon->dhcp_conf = configs; |
| } |
| |
| 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; |
| struct crec *crec; |
| |
| for (config = configs; config; config = config->next) |
| if (config->flags & CONFIG_ADDR_HOSTS) |
| config->flags &= ~(CONFIG_ADDR | CONFIG_ADDR_HOSTS); |
| |
| for (config = configs; config; config = config->next) |
| if (!(config->flags & CONFIG_ADDR) && |
| (config->flags & CONFIG_NAME) && |
| (crec = cache_find_by_name(NULL, config->hostname, 0, F_IPV4)) && |
| (crec->flags & F_HOSTS)) |
| { |
| if (config_find_by_address(configs, crec->addr.addr.addr.addr4)) |
| syslog(LOG_WARNING, _("duplicate IP address %s (%s) in dhcp-config directive"), |
| inet_ntoa(crec->addr.addr.addr.addr4), config->hostname); |
| else |
| { |
| config->addr = crec->addr.addr.addr.addr4; |
| config->flags |= CONFIG_ADDR | CONFIG_ADDR_HOSTS; |
| } |
| } |
| } |
| |
| /* If we've not found a hostname any other way, try and see if there's one in /etc/hosts |
| for this address. If it has a domain part, that must match the set domain and |
| it gets stripped. */ |
| char *host_from_dns(struct daemon *daemon, struct in_addr addr) |
| { |
| struct crec *lookup = cache_find_by_addr(NULL, (struct all_addr *)&addr, 0, F_IPV4); |
| char *hostname = NULL; |
| |
| if (lookup && (lookup->flags & F_HOSTS)) |
| { |
| hostname = daemon->dhcp_buff; |
| strncpy(hostname, cache_get_name(lookup), 256); |
| hostname[255] = 0; |
| hostname = strip_hostname(daemon, hostname); |
| } |
| |
| return hostname; |
| } |
| |
| char *strip_hostname(struct daemon *daemon, char *hostname) |
| { |
| char *dot = strchr(hostname, '.'); |
| if (dot) |
| { |
| if (!daemon->domain_suffix || !hostname_isequal(dot+1, daemon->domain_suffix)) |
| { |
| syslog(LOG_WARNING, _("Ignoring DHCP host name %s because it has an illegal domain part"), hostname); |
| hostname = NULL; |
| } |
| else |
| { |
| *dot = 0; /* truncate */ |
| if (strlen(hostname) == 0) |
| hostname = NULL; /* nothing left */ |
| } |
| } |
| return hostname; |
| } |