Annotation of embedaddon/dnsmasq/src/dhcp.c, revision 1.1.1.5

1.1.1.5 ! misho       1: /* dnsmasq is Copyright (c) 2000-2022 Simon Kelley
1.1       misho       2: 
                      3:    This program is free software; you can redistribute it and/or modify
                      4:    it under the terms of the GNU General Public License as published by
                      5:    the Free Software Foundation; version 2 dated June, 1991, or
                      6:    (at your option) version 3 dated 29 June, 2007.
                      7:  
                      8:    This program is distributed in the hope that it will be useful,
                      9:    but WITHOUT ANY WARRANTY; without even the implied warranty of
                     10:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     11:    GNU General Public License for more details.
                     12:      
                     13:    You should have received a copy of the GNU General Public License
                     14:    along with this program.  If not, see <http://www.gnu.org/licenses/>.
                     15: */
                     16: 
                     17: #include "dnsmasq.h"
                     18: 
                     19: #ifdef HAVE_DHCP
                     20: 
                     21: struct iface_param {
                     22:   struct dhcp_context *current;
                     23:   int ind;
                     24: };
                     25: 
                     26: struct match_param {
                     27:   int ind, matched;
                     28:   struct in_addr netmask, broadcast, addr;
                     29: };
                     30: 
1.1.1.2   misho      31: static int complete_context(struct in_addr local, int if_index, char *label,
1.1       misho      32:                            struct in_addr netmask, struct in_addr broadcast, void *vparam);
1.1.1.2   misho      33: static int check_listen_addrs(struct in_addr local, int if_index, char *label,
1.1       misho      34:                              struct in_addr netmask, struct in_addr broadcast, void *vparam);
1.1.1.5 ! misho      35: static int relay_upstream4(int iface_index, struct dhcp_packet *mess, size_t sz);
1.1.1.2   misho      36: static struct dhcp_relay *relay_reply4(struct dhcp_packet *mess, char *arrival_interface);
1.1       misho      37: 
                     38: static int make_fd(int port)
                     39: {
                     40:   int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
                     41:   struct sockaddr_in saddr;
                     42:   int oneopt = 1;
                     43: #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
                     44:   int mtu = IP_PMTUDISC_DONT;
                     45: #endif
                     46: #if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
                     47:   int tos = IPTOS_CLASS_CS6;
                     48: #endif
                     49: 
                     50:   if (fd == -1)
                     51:     die (_("cannot create DHCP socket: %s"), NULL, EC_BADNET);
                     52:   
                     53:   if (!fix_fd(fd) ||
                     54: #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
                     55:       setsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER, &mtu, sizeof(mtu)) == -1 ||
                     56: #endif
                     57: #if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
                     58:       setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1 ||
                     59: #endif
                     60: #if defined(HAVE_LINUX_NETWORK)
                     61:       setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &oneopt, sizeof(oneopt)) == -1 ||
                     62: #else
                     63:       setsockopt(fd, IPPROTO_IP, IP_RECVIF, &oneopt, sizeof(oneopt)) == -1 ||
                     64: #endif
                     65:       setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &oneopt, sizeof(oneopt)) == -1)  
                     66:     die(_("failed to set options on DHCP socket: %s"), NULL, EC_BADNET);
                     67:   
1.1.1.4   misho      68:   /* When bind-interfaces is set, there might be more than one dnsmasq
1.1       misho      69:      instance binding port 67. That's OK if they serve different networks.
1.1.1.4   misho      70:      Need to set REUSEADDR|REUSEPORT to make this possible.
1.1       misho      71:      Handle the case that REUSEPORT is defined, but the kernel doesn't 
                     72:      support it. This handles the introduction of REUSEPORT on Linux. */
                     73:   if (option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND))
                     74:     {
1.1.1.2   misho      75:       int rc = 0;
1.1       misho      76: 
                     77: #ifdef SO_REUSEPORT
                     78:       if ((rc = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &oneopt, sizeof(oneopt))) == -1 && 
1.1.1.2   misho      79:          errno == ENOPROTOOPT)
                     80:        rc = 0;
1.1       misho      81: #endif
                     82:       
1.1.1.2   misho      83:       if (rc != -1)
1.1       misho      84:        rc = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &oneopt, sizeof(oneopt));
                     85:       
                     86:       if (rc == -1)
                     87:        die(_("failed to set SO_REUSE{ADDR|PORT} on DHCP socket: %s"), NULL, EC_BADNET);
                     88:     }
                     89:   
                     90:   memset(&saddr, 0, sizeof(saddr));
                     91:   saddr.sin_family = AF_INET;
                     92:   saddr.sin_port = htons(port);
                     93:   saddr.sin_addr.s_addr = INADDR_ANY;
                     94: #ifdef HAVE_SOCKADDR_SA_LEN
                     95:   saddr.sin_len = sizeof(struct sockaddr_in);
                     96: #endif
                     97: 
                     98:   if (bind(fd, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in)))
                     99:     die(_("failed to bind DHCP server socket: %s"), NULL, EC_BADNET);
                    100: 
                    101:   return fd;
                    102: }
                    103: 
                    104: void dhcp_init(void)
                    105: {
                    106: #if defined(HAVE_BSD_NETWORK)
                    107:   int oneopt = 1;
                    108: #endif
                    109: 
                    110:   daemon->dhcpfd = make_fd(daemon->dhcp_server_port);
                    111:   if (daemon->enable_pxe)
                    112:     daemon->pxefd = make_fd(PXE_PORT);
                    113:   else
                    114:     daemon->pxefd = -1;
                    115: 
                    116: #if defined(HAVE_BSD_NETWORK)
                    117:   /* When we're not using capabilities, we need to do this here before
                    118:      we drop root. Also, set buffer size small, to avoid wasting
                    119:      kernel buffers */
                    120:   
                    121:   if (option_bool(OPT_NO_PING))
                    122:     daemon->dhcp_icmp_fd = -1;
                    123:   else if ((daemon->dhcp_icmp_fd = make_icmp_sock()) == -1 ||
                    124:           setsockopt(daemon->dhcp_icmp_fd, SOL_SOCKET, SO_RCVBUF, &oneopt, sizeof(oneopt)) == -1 )
                    125:     die(_("cannot create ICMP raw socket: %s."), NULL, EC_BADNET);
                    126:   
                    127:   /* Make BPF raw send socket */
                    128:   init_bpf();
                    129: #endif  
                    130: }
                    131: 
                    132: void dhcp_packet(time_t now, int pxe_fd)
                    133: {
                    134:   int fd = pxe_fd ? daemon->pxefd : daemon->dhcpfd;
                    135:   struct dhcp_packet *mess;
                    136:   struct dhcp_context *context;
1.1.1.2   misho     137:   struct dhcp_relay *relay;
                    138:   int is_relay_reply = 0;
1.1       misho     139:   struct iname *tmp;
                    140:   struct ifreq ifr;
                    141:   struct msghdr msg;
                    142:   struct sockaddr_in dest;
                    143:   struct cmsghdr *cmptr;
                    144:   struct iovec iov;
                    145:   ssize_t sz; 
1.1.1.4   misho     146:   int iface_index = 0, unicast_dest = 0, is_inform = 0, loopback = 0;
1.1.1.3   misho     147:   int rcvd_iface_index;
1.1       misho     148:   struct in_addr iface_addr;
                    149:   struct iface_param parm;
1.1.1.4   misho     150:   time_t recvtime = now;
1.1       misho     151: #ifdef HAVE_LINUX_NETWORK
                    152:   struct arpreq arp_req;
1.1.1.4   misho     153:   struct timeval tv;
1.1       misho     154: #endif
                    155:   
                    156:   union {
                    157:     struct cmsghdr align; /* this ensures alignment */
                    158: #if defined(HAVE_LINUX_NETWORK)
                    159:     char control[CMSG_SPACE(sizeof(struct in_pktinfo))];
                    160: #elif defined(HAVE_SOLARIS_NETWORK)
                    161:     char control[CMSG_SPACE(sizeof(unsigned int))];
                    162: #elif defined(HAVE_BSD_NETWORK) 
                    163:     char control[CMSG_SPACE(sizeof(struct sockaddr_dl))];
                    164: #endif
                    165:   } control_u;
                    166:   struct dhcp_bridge *bridge, *alias;
                    167: 
                    168:   msg.msg_controllen = sizeof(control_u);
                    169:   msg.msg_control = control_u.control;
                    170:   msg.msg_name = &dest;
                    171:   msg.msg_namelen = sizeof(dest);
                    172:   msg.msg_iov = &daemon->dhcp_packet;
                    173:   msg.msg_iovlen = 1;
                    174:   
                    175:   if ((sz = recv_dhcp_packet(fd, &msg)) == -1 || 
                    176:       (sz < (ssize_t)(sizeof(*mess) - sizeof(mess->options)))) 
                    177:     return;
1.1.1.5 ! misho     178:   
        !           179: #ifdef HAVE_DUMPFILE
        !           180:   dump_packet_udp(DUMP_DHCP, (void *)daemon->dhcp_packet.iov_base, sz, (union mysockaddr *)&dest, NULL, fd);
        !           181: #endif
        !           182:   
        !           183: #if defined (HAVE_LINUX_NETWORK)
1.1.1.4   misho     184:   if (ioctl(fd, SIOCGSTAMP, &tv) == 0)
                    185:     recvtime = tv.tv_sec;
1.1.1.5 ! misho     186:   
1.1       misho     187:   if (msg.msg_controllen >= sizeof(struct cmsghdr))
                    188:     for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
                    189:       if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO)
                    190:        {
                    191:          union {
                    192:            unsigned char *c;
                    193:            struct in_pktinfo *p;
                    194:          } p;
                    195:          p.c = CMSG_DATA(cmptr);
                    196:          iface_index = p.p->ipi_ifindex;
                    197:          if (p.p->ipi_addr.s_addr != INADDR_BROADCAST)
                    198:            unicast_dest = 1;
                    199:        }
                    200: 
                    201: #elif defined(HAVE_BSD_NETWORK) 
                    202:   if (msg.msg_controllen >= sizeof(struct cmsghdr))
                    203:     for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
                    204:       if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
                    205:         {
                    206:          union {
                    207:             unsigned char *c;
                    208:             struct sockaddr_dl *s;
                    209:           } p;
                    210:          p.c = CMSG_DATA(cmptr);
                    211:          iface_index = p.s->sdl_index;
                    212:        }
                    213:   
                    214: #elif defined(HAVE_SOLARIS_NETWORK) 
                    215:   if (msg.msg_controllen >= sizeof(struct cmsghdr))
                    216:     for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
                    217:       if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
                    218:        {
                    219:          union {
                    220:            unsigned char *c;
                    221:            unsigned int *i;
                    222:          } p;
                    223:          p.c = CMSG_DATA(cmptr);
                    224:          iface_index = *(p.i);
                    225:        }
                    226: #endif
                    227:        
1.1.1.4   misho     228:   if (!indextoname(daemon->dhcpfd, iface_index, ifr.ifr_name) ||
                    229:       ioctl(daemon->dhcpfd, SIOCGIFFLAGS, &ifr) != 0)
1.1       misho     230:     return;
1.1.1.4   misho     231:   
                    232:   mess = (struct dhcp_packet *)daemon->dhcp_packet.iov_base;
                    233:   loopback = !mess->giaddr.s_addr && (ifr.ifr_flags & IFF_LOOPBACK);
                    234:   
1.1       misho     235: #ifdef HAVE_LINUX_NETWORK
                    236:   /* ARP fiddling uses original interface even if we pretend to use a different one. */
1.1.1.4   misho     237:   safe_strncpy(arp_req.arp_dev, ifr.ifr_name, sizeof(arp_req.arp_dev));
1.1       misho     238: #endif 
                    239: 
1.1.1.3   misho     240:   /* If the interface on which the DHCP request was received is an
                    241:      alias of some other interface (as specified by the
                    242:      --bridge-interface option), change ifr.ifr_name so that we look
                    243:      for DHCP contexts associated with the aliased interface instead
                    244:      of with the aliasing one. */
                    245:   rcvd_iface_index = iface_index;
1.1       misho     246:   for (bridge = daemon->bridges; bridge; bridge = bridge->next)
                    247:     {
                    248:       for (alias = bridge->alias; alias; alias = alias->next)
1.1.1.3   misho     249:        if (wildcard_matchn(alias->iface, ifr.ifr_name, IF_NAMESIZE))
1.1       misho     250:          {
                    251:            if (!(iface_index = if_nametoindex(bridge->iface)))
                    252:              {
1.1.1.3   misho     253:                my_syslog(MS_DHCP | LOG_WARNING,
                    254:                          _("unknown interface %s in bridge-interface"),
                    255:                          bridge->iface);
1.1       misho     256:                return;
                    257:              }
                    258:            else 
                    259:              {
1.1.1.4   misho     260:                safe_strncpy(ifr.ifr_name,  bridge->iface, sizeof(ifr.ifr_name));
1.1       misho     261:                break;
                    262:              }
                    263:          }
                    264:       
                    265:       if (alias)
                    266:        break;
                    267:     }
                    268: 
                    269: #ifdef MSG_BCAST
                    270:   /* OpenBSD tells us when a packet was broadcast */
                    271:   if (!(msg.msg_flags & MSG_BCAST))
                    272:     unicast_dest = 1;
                    273: #endif
                    274:   
1.1.1.2   misho     275:   if ((relay = relay_reply4((struct dhcp_packet *)daemon->dhcp_packet.iov_base, ifr.ifr_name)))
1.1       misho     276:     {
1.1.1.2   misho     277:       /* Reply from server, using us as relay. */
1.1.1.4   misho     278:       rcvd_iface_index = relay->iface_index;
                    279:       if (!indextoname(daemon->dhcpfd, rcvd_iface_index, ifr.ifr_name))
1.1.1.2   misho     280:        return;
                    281:       is_relay_reply = 1; 
                    282:       iov.iov_len = sz;
                    283: #ifdef HAVE_LINUX_NETWORK
1.1.1.4   misho     284:       safe_strncpy(arp_req.arp_dev, ifr.ifr_name, sizeof(arp_req.arp_dev));
1.1.1.2   misho     285: #endif 
1.1       misho     286:     }
1.1.1.2   misho     287:   else
1.1       misho     288:     {
1.1.1.2   misho     289:       ifr.ifr_addr.sa_family = AF_INET;
                    290:       if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) != -1 )
                    291:        iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
                    292:       else
                    293:        {
1.1.1.4   misho     294:          if (iface_check(AF_INET, NULL, ifr.ifr_name, NULL))
                    295:            my_syslog(MS_DHCP | LOG_WARNING, _("DHCP packet received on %s which has no address"), ifr.ifr_name);
1.1.1.2   misho     296:          return;
                    297:        }
                    298:       
                    299:       for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
                    300:        if (tmp->name && wildcard_match(tmp->name, ifr.ifr_name))
                    301:          return;
                    302:       
                    303:       /* unlinked contexts/relays are marked by context->current == context */
                    304:       for (context = daemon->dhcp; context; context = context->next)
                    305:        context->current = context;
                    306:       
                    307:       parm.current = NULL;
                    308:       parm.ind = iface_index;
1.1       misho     309:       
1.1.1.4   misho     310:       if (!iface_check(AF_INET, (union all_addr *)&iface_addr, ifr.ifr_name, NULL))
1.1.1.2   misho     311:        {
                    312:          /* If we failed to match the primary address of the interface, see if we've got a --listen-address
                    313:             for a secondary */
                    314:          struct match_param match;
                    315:          
                    316:          match.matched = 0;
                    317:          match.ind = iface_index;
                    318:          
                    319:          if (!daemon->if_addrs ||
                    320:              !iface_enumerate(AF_INET, &match, check_listen_addrs) ||
                    321:              !match.matched)
                    322:            return;
                    323:          
                    324:          iface_addr = match.addr;
                    325:          /* make sure secondary address gets priority in case
                    326:             there is more than one address on the interface in the same subnet */
                    327:          complete_context(match.addr, iface_index, NULL, match.netmask, match.broadcast, &parm);
                    328:        }    
1.1.1.5 ! misho     329:             
        !           330:       if (relay_upstream4(iface_index, mess, (size_t)sz))
        !           331:        return;
1.1.1.2   misho     332:       
                    333:       if (!iface_enumerate(AF_INET, &parm, complete_context))
                    334:        return;
                    335: 
1.1.1.5 ! misho     336:       /* Check for a relay again after iface_enumerate/complete_context has had
        !           337:         chance to fill in relay->iface_index fields. This handles first time through
        !           338:         and any changes in interface config. */
        !           339:        if (relay_upstream4(iface_index, mess, (size_t)sz))
1.1.1.2   misho     340:        return;
1.1.1.5 ! misho     341:        
1.1.1.2   misho     342:       /* May have configured relay, but not DHCP server */
                    343:       if (!daemon->dhcp)
1.1       misho     344:        return;
                    345: 
1.1.1.2   misho     346:       lease_prune(NULL, now); /* lose any expired leases */
                    347:       iov.iov_len = dhcp_reply(parm.current, ifr.ifr_name, iface_index, (size_t)sz, 
1.1.1.4   misho     348:                               now, unicast_dest, loopback, &is_inform, pxe_fd, iface_addr, recvtime);
1.1.1.2   misho     349:       lease_update_file(now);
                    350:       lease_update_dns(0);
1.1       misho     351:       
1.1.1.2   misho     352:       if (iov.iov_len == 0)
                    353:        return;
                    354:     }
1.1.1.4   misho     355: 
1.1       misho     356:   msg.msg_name = &dest;
                    357:   msg.msg_namelen = sizeof(dest);
                    358:   msg.msg_control = NULL;
                    359:   msg.msg_controllen = 0;
                    360:   msg.msg_iov = &iov;
                    361:   iov.iov_base = daemon->dhcp_packet.iov_base;
                    362:   
                    363:   /* packet buffer may have moved */
                    364:   mess = (struct dhcp_packet *)daemon->dhcp_packet.iov_base;
                    365:   
                    366: #ifdef HAVE_SOCKADDR_SA_LEN
                    367:   dest.sin_len = sizeof(struct sockaddr_in);
                    368: #endif
                    369:   
                    370:   if (pxe_fd)
                    371:     { 
                    372:       if (mess->ciaddr.s_addr != 0)
                    373:        dest.sin_addr = mess->ciaddr;
                    374:     }
1.1.1.2   misho     375:   else if (mess->giaddr.s_addr && !is_relay_reply)
1.1       misho     376:     {
                    377:       /* Send to BOOTP relay  */
                    378:       dest.sin_port = htons(daemon->dhcp_server_port);
                    379:       dest.sin_addr = mess->giaddr; 
                    380:     }
                    381:   else if (mess->ciaddr.s_addr)
                    382:     {
                    383:       /* If the client's idea of its own address tallys with
                    384:         the source address in the request packet, we believe the
                    385:         source port too, and send back to that.  If we're replying 
                    386:         to a DHCPINFORM, trust the source address always. */
                    387:       if ((!is_inform && dest.sin_addr.s_addr != mess->ciaddr.s_addr) ||
1.1.1.2   misho     388:          dest.sin_port == 0 || dest.sin_addr.s_addr == 0 || is_relay_reply)
1.1       misho     389:        {
                    390:          dest.sin_port = htons(daemon->dhcp_client_port); 
                    391:          dest.sin_addr = mess->ciaddr;
                    392:        }
                    393:     } 
                    394: #if defined(HAVE_LINUX_NETWORK)
1.1.1.3   misho     395:   else
1.1       misho     396:     {
1.1.1.3   misho     397:       /* fill cmsg for outbound interface (both broadcast & unicast) */
1.1       misho     398:       struct in_pktinfo *pkt;
                    399:       msg.msg_control = control_u.control;
                    400:       msg.msg_controllen = sizeof(control_u);
                    401:       cmptr = CMSG_FIRSTHDR(&msg);
                    402:       pkt = (struct in_pktinfo *)CMSG_DATA(cmptr);
1.1.1.3   misho     403:       pkt->ipi_ifindex = rcvd_iface_index;
1.1       misho     404:       pkt->ipi_spec_dst.s_addr = 0;
1.1.1.4   misho     405:       msg.msg_controllen = CMSG_SPACE(sizeof(struct in_pktinfo));
                    406:       cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
1.1       misho     407:       cmptr->cmsg_level = IPPROTO_IP;
1.1.1.3   misho     408:       cmptr->cmsg_type = IP_PKTINFO;
                    409: 
                    410:       if ((ntohs(mess->flags) & 0x8000) || mess->hlen == 0 ||
                    411:          mess->hlen > sizeof(ifr.ifr_addr.sa_data) || mess->htype == 0)
                    412:         {
                    413:           /* broadcast to 255.255.255.255 (or mac address invalid) */
                    414:           dest.sin_addr.s_addr = INADDR_BROADCAST;
                    415:           dest.sin_port = htons(daemon->dhcp_client_port);
                    416:         }
                    417:       else
                    418:         {
                    419:           /* unicast to unconfigured client. Inject mac address direct into ARP cache.
                    420:           struct sockaddr limits size to 14 bytes. */
                    421:           dest.sin_addr = mess->yiaddr;
                    422:           dest.sin_port = htons(daemon->dhcp_client_port);
                    423:           memcpy(&arp_req.arp_pa, &dest, sizeof(struct sockaddr_in));
                    424:           arp_req.arp_ha.sa_family = mess->htype;
                    425:           memcpy(arp_req.arp_ha.sa_data, mess->chaddr, mess->hlen);
                    426:           /* interface name already copied in */
                    427:           arp_req.arp_flags = ATF_COM;
                    428:           if (ioctl(daemon->dhcpfd, SIOCSARP, &arp_req) == -1)
                    429:             my_syslog(MS_DHCP | LOG_ERR, _("ARP-cache injection failed: %s"), strerror(errno));
                    430:         }
1.1       misho     431:     }
                    432: #elif defined(HAVE_SOLARIS_NETWORK)
                    433:   else if ((ntohs(mess->flags) & 0x8000) || mess->hlen != ETHER_ADDR_LEN || mess->htype != ARPHRD_ETHER)
                    434:     {
                    435:       /* broadcast to 255.255.255.255 (or mac address invalid) */
                    436:       dest.sin_addr.s_addr = INADDR_BROADCAST;
                    437:       dest.sin_port = htons(daemon->dhcp_client_port);
                    438:       /* note that we don't specify the interface here: that's done by the
                    439:         IP_BOUND_IF sockopt lower down. */
                    440:     }
                    441:   else
                    442:     {
                    443:       /* unicast to unconfigured client. Inject mac address direct into ARP cache. 
                    444:         Note that this only works for ethernet on solaris, because we use SIOCSARP
                    445:         and not SIOCSXARP, which would be perfect, except that it returns ENXIO 
                    446:         mysteriously. Bah. Fall back to broadcast for other net types. */
                    447:       struct arpreq req;
                    448:       dest.sin_addr = mess->yiaddr;
                    449:       dest.sin_port = htons(daemon->dhcp_client_port);
                    450:       *((struct sockaddr_in *)&req.arp_pa) = dest;
                    451:       req.arp_ha.sa_family = AF_UNSPEC;
                    452:       memcpy(req.arp_ha.sa_data, mess->chaddr, mess->hlen);
                    453:       req.arp_flags = ATF_COM;
                    454:       ioctl(daemon->dhcpfd, SIOCSARP, &req);
                    455:     }
                    456: #elif defined(HAVE_BSD_NETWORK)
                    457:   else 
                    458:     {
1.1.1.5 ! misho     459: #ifdef HAVE_DUMPFILE
        !           460:       if (ntohs(mess->flags) & 0x8000)
        !           461:         dest.sin_addr.s_addr = INADDR_BROADCAST;
        !           462:       else
        !           463:         dest.sin_addr = mess->yiaddr;
        !           464:       dest.sin_port = htons(daemon->dhcp_client_port);
        !           465:       
        !           466:       dump_packet_udp(DUMP_DHCP, (void *)iov.iov_base, iov.iov_len, NULL,
        !           467:                      (union mysockaddr *)&dest, fd);
        !           468: #endif
        !           469:       
1.1       misho     470:       send_via_bpf(mess, iov.iov_len, iface_addr, &ifr);
                    471:       return;
                    472:     }
                    473: #endif
                    474:    
                    475: #ifdef HAVE_SOLARIS_NETWORK
                    476:   setsockopt(fd, IPPROTO_IP, IP_BOUND_IF, &iface_index, sizeof(iface_index));
                    477: #endif
1.1.1.5 ! misho     478: 
        !           479: #ifdef HAVE_DUMPFILE
        !           480:   dump_packet_udp(DUMP_DHCP, (void *)iov.iov_base, iov.iov_len, NULL,
        !           481:                  (union mysockaddr *)&dest, fd);
        !           482: #endif
1.1       misho     483:   
1.1.1.3   misho     484:   while(retry_send(sendmsg(fd, &msg, 0)));
                    485: 
                    486:   /* This can fail when, eg, iptables DROPS destination 255.255.255.255 */
                    487:   if (errno != 0)
1.1.1.5 ! misho     488:     {
        !           489:       inet_ntop(AF_INET, &dest.sin_addr, daemon->addrbuff, ADDRSTRLEN);
        !           490:       my_syslog(MS_DHCP | LOG_WARNING, _("Error sending DHCP packet to %s: %s"),
        !           491:                daemon->addrbuff, strerror(errno));
        !           492:     }
1.1       misho     493: }
1.1.1.3   misho     494: 
1.1       misho     495: /* check against secondary interface addresses */
1.1.1.2   misho     496: static int check_listen_addrs(struct in_addr local, int if_index, char *label,
1.1       misho     497:                              struct in_addr netmask, struct in_addr broadcast, void *vparam)
                    498: {
                    499:   struct match_param *param = vparam;
                    500:   struct iname *tmp;
                    501: 
1.1.1.2   misho     502:   (void) label;
                    503: 
1.1       misho     504:   if (if_index == param->ind)
                    505:     {
                    506:       for (tmp = daemon->if_addrs; tmp; tmp = tmp->next)
                    507:        if ( tmp->addr.sa.sa_family == AF_INET &&
                    508:             tmp->addr.in.sin_addr.s_addr == local.s_addr)
                    509:          {
                    510:            param->matched = 1;
                    511:            param->addr = local;
                    512:            param->netmask = netmask;
                    513:            param->broadcast = broadcast;
                    514:            break;
                    515:          }
                    516:     }
                    517:   
                    518:   return 1;
                    519: }
                    520: 
                    521: /* This is a complex routine: it gets called with each (address,netmask,broadcast) triple 
                    522:    of each interface (and any relay address) and does the  following things:
                    523: 
                    524:    1) Discards stuff for interfaces other than the one on which a DHCP packet just arrived.
                    525:    2) Fills in any netmask and broadcast addresses which have not been explicitly configured.
                    526:    3) Fills in local (this host) and router (this host or relay) addresses.
                    527:    4) Links contexts which are valid for hosts directly connected to the arrival interface on ->current.
                    528: 
1.1.1.4   misho     529:    Note that the current chain may be superseded later for configured hosts or those coming via gateways. */
1.1       misho     530: 
1.1.1.4   misho     531: static void guess_range_netmask(struct in_addr addr, struct in_addr netmask)
1.1       misho     532: {
                    533:   struct dhcp_context *context;
1.1.1.2   misho     534: 
1.1       misho     535:   for (context = daemon->dhcp; context; context = context->next)
1.1.1.4   misho     536:     if (!(context->flags & CONTEXT_NETMASK) &&
                    537:        (is_same_net(addr, context->start, netmask) ||
                    538:         is_same_net(addr, context->end, netmask)))
1.1       misho     539:       { 
                    540:        if (context->netmask.s_addr != netmask.s_addr &&
1.1.1.4   misho     541:            !(is_same_net(addr, context->start, netmask) &&
                    542:              is_same_net(addr, context->end, netmask)))
1.1       misho     543:          {
1.1.1.5 ! misho     544:            inet_ntop(AF_INET, &context->start, daemon->dhcp_buff, DHCP_BUFF_SZ);
        !           545:            inet_ntop(AF_INET, &context->end, daemon->dhcp_buff2, DHCP_BUFF_SZ);
        !           546:            inet_ntop(AF_INET, &netmask, daemon->addrbuff, ADDRSTRLEN);
1.1       misho     547:            my_syslog(MS_DHCP | LOG_WARNING, _("DHCP range %s -- %s is not consistent with netmask %s"),
1.1.1.5 ! misho     548:                      daemon->dhcp_buff, daemon->dhcp_buff2, daemon->addrbuff);
1.1       misho     549:          }     
1.1.1.4   misho     550:        context->netmask = netmask;
1.1       misho     551:       }
1.1.1.4   misho     552: }
                    553: 
                    554: static int complete_context(struct in_addr local, int if_index, char *label,
                    555:                            struct in_addr netmask, struct in_addr broadcast, void *vparam)
                    556: {
                    557:   struct dhcp_context *context;
                    558:   struct dhcp_relay *relay;
                    559:   struct iface_param *param = vparam;
                    560:   struct shared_network *share;
                    561:   
                    562:   (void)label;
                    563: 
                    564:   for (share = daemon->shared_networks; share; share = share->next)
                    565:     {
1.1       misho     566:       
1.1.1.4   misho     567: #ifdef HAVE_DHCP6
                    568:       if (share->shared_addr.s_addr == 0)
                    569:        continue;
                    570: #endif
                    571:       
                    572:       if (share->if_index != 0)
                    573:        {
                    574:          if (share->if_index != if_index)
                    575:            continue;
                    576:        }
                    577:       else
                    578:        {
                    579:          if (share->match_addr.s_addr != local.s_addr)
                    580:            continue;
                    581:        }
                    582: 
                    583:       for (context = daemon->dhcp; context; context = context->next)
                    584:        {
                    585:          if (context->netmask.s_addr != 0 &&
                    586:              is_same_net(share->shared_addr, context->start, context->netmask) &&
                    587:              is_same_net(share->shared_addr, context->end, context->netmask))
                    588:            {
                    589:              /* link it onto the current chain if we've not seen it before */
                    590:              if (context->current == context)
                    591:                {
                    592:                  /* For a shared network, we have no way to guess what the default route should be. */
                    593:                  context->router.s_addr = 0;
                    594:                  context->local = local; /* Use configured address for Server Identifier */
                    595:                  context->current = param->current;
                    596:                  param->current = context;
                    597:                }
                    598:              
                    599:              if (!(context->flags & CONTEXT_BRDCAST))
                    600:                context->broadcast.s_addr  = context->start.s_addr | ~context->netmask.s_addr;
                    601:            }           
                    602:        }
                    603:     }
                    604: 
                    605:   guess_range_netmask(local, netmask);
                    606:   
                    607:   for (context = daemon->dhcp; context; context = context->next)
                    608:     {
1.1       misho     609:       if (context->netmask.s_addr != 0 &&
                    610:          is_same_net(local, context->start, context->netmask) &&
                    611:          is_same_net(local, context->end, context->netmask))
                    612:        {
                    613:          /* link it onto the current chain if we've not seen it before */
                    614:          if (if_index == param->ind && context->current == context)
                    615:            {
                    616:              context->router = local;
                    617:              context->local = local;
                    618:              context->current = param->current;
                    619:              param->current = context;
                    620:            }
                    621:          
                    622:          if (!(context->flags & CONTEXT_BRDCAST))
                    623:            {
                    624:              if (is_same_net(broadcast, context->start, context->netmask))
                    625:                context->broadcast = broadcast;
                    626:              else 
                    627:                context->broadcast.s_addr  = context->start.s_addr | ~context->netmask.s_addr;
                    628:            }
                    629:        }               
                    630:     }
                    631: 
1.1.1.2   misho     632:   for (relay = daemon->relay4; relay; relay = relay->next)
1.1.1.5 ! misho     633:     if (relay->local.addr4.s_addr == local.s_addr)
        !           634:       relay->iface_index = if_index;
        !           635:   
1.1       misho     636:   return 1;
                    637: }
                    638:          
                    639: struct dhcp_context *address_available(struct dhcp_context *context, 
                    640:                                       struct in_addr taddr,
                    641:                                       struct dhcp_netid *netids)
                    642: {
                    643:   /* Check is an address is OK for this network, check all
                    644:      possible ranges. Make sure that the address isn't in use
                    645:      by the server itself. */
                    646:   
                    647:   unsigned int start, end, addr = ntohl(taddr.s_addr);
                    648:   struct dhcp_context *tmp;
                    649: 
                    650:   for (tmp = context; tmp; tmp = tmp->current)
                    651:     if (taddr.s_addr == context->router.s_addr)
                    652:       return NULL;
                    653:   
                    654:   for (tmp = context; tmp; tmp = tmp->current)
                    655:     {
                    656:       start = ntohl(tmp->start.s_addr);
                    657:       end = ntohl(tmp->end.s_addr);
                    658: 
                    659:       if (!(tmp->flags & (CONTEXT_STATIC | CONTEXT_PROXY)) &&
                    660:          addr >= start &&
                    661:          addr <= end &&
                    662:          match_netid(tmp->filter, netids, 1))
                    663:        return tmp;
                    664:     }
                    665: 
                    666:   return NULL;
                    667: }
                    668: 
                    669: struct dhcp_context *narrow_context(struct dhcp_context *context, 
                    670:                                    struct in_addr taddr,
                    671:                                    struct dhcp_netid *netids)
                    672: {
                    673:   /* We start of with a set of possible contexts, all on the current physical interface.
                    674:      These are chained on ->current.
1.1.1.4   misho     675:      Here we have an address, and return the actual context corresponding to that
1.1       misho     676:      address. Note that none may fit, if the address came a dhcp-host and is outside
                    677:      any dhcp-range. In that case we return a static range if possible, or failing that,
                    678:      any context on the correct subnet. (If there's more than one, this is a dodgy 
                    679:      configuration: maybe there should be a warning.) */
                    680:   
                    681:   struct dhcp_context *tmp;
                    682: 
                    683:   if (!(tmp = address_available(context, taddr, netids)))
                    684:     {
                    685:       for (tmp = context; tmp; tmp = tmp->current)
                    686:        if (match_netid(tmp->filter, netids, 1) &&
                    687:            is_same_net(taddr, tmp->start, tmp->netmask) && 
                    688:            (tmp->flags & CONTEXT_STATIC))
                    689:          break;
                    690:       
                    691:       if (!tmp)
                    692:        for (tmp = context; tmp; tmp = tmp->current)
                    693:          if (match_netid(tmp->filter, netids, 1) &&
                    694:              is_same_net(taddr, tmp->start, tmp->netmask) &&
                    695:              !(tmp->flags & CONTEXT_PROXY))
                    696:            break;
                    697:     }
                    698:   
                    699:   /* Only one context allowed now */
                    700:   if (tmp)
                    701:     tmp->current = NULL;
                    702:   
                    703:   return tmp;
                    704: }
                    705: 
                    706: struct dhcp_config *config_find_by_address(struct dhcp_config *configs, struct in_addr addr)
                    707: {
                    708:   struct dhcp_config *config;
                    709:   
                    710:   for (config = configs; config; config = config->next)
                    711:     if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr)
                    712:       return config;
                    713: 
                    714:   return NULL;
                    715: }
                    716: 
1.1.1.4   misho     717: /* Check if and address is in use by sending ICMP ping.
                    718:    This wrapper handles a cache and load-limiting.
                    719:    Return is NULL is address in use, or a pointer to a cache entry
                    720:    recording that it isn't. */
                    721: struct ping_result *do_icmp_ping(time_t now, struct in_addr addr, unsigned int hash, int loopback)
                    722: {
                    723:   static struct ping_result dummy;
                    724:   struct ping_result *r, *victim = NULL;
                    725:   int count, max = (int)(0.6 * (((float)PING_CACHE_TIME)/
                    726:                                ((float)PING_WAIT)));
                    727: 
                    728:   /* check if we failed to ping addr sometime in the last
                    729:      PING_CACHE_TIME seconds. If so, assume the same situation still exists.
                    730:      This avoids problems when a stupid client bangs
                    731:      on us repeatedly. As a final check, if we did more
                    732:      than 60% of the possible ping checks in the last 
                    733:      PING_CACHE_TIME, we are in high-load mode, so don't do any more. */
                    734:   for (count = 0, r = daemon->ping_results; r; r = r->next)
                    735:     if (difftime(now, r->time) >  (float)PING_CACHE_TIME)
                    736:       victim = r; /* old record */
                    737:     else 
                    738:       {
                    739:        count++;
                    740:        if (r->addr.s_addr == addr.s_addr)
                    741:          return r;
                    742:       }
                    743:   
                    744:   /* didn't find cached entry */
                    745:   if ((count >= max) || option_bool(OPT_NO_PING) || loopback)
                    746:     {
                    747:       /* overloaded, or configured not to check, loopback interface, return "not in use" */
                    748:       dummy.hash = hash;
                    749:       return &dummy;
                    750:     }
                    751:   else if (icmp_ping(addr))
                    752:     return NULL; /* address in use. */
                    753:   else
                    754:     {
                    755:       /* at this point victim may hold an expired record */
                    756:       if (!victim)
                    757:        {
                    758:          if ((victim = whine_malloc(sizeof(struct ping_result))))
                    759:            {
                    760:              victim->next = daemon->ping_results;
                    761:              daemon->ping_results = victim;
                    762:            }
                    763:        }
                    764:       
                    765:       /* record that this address is OK for 30s 
                    766:         without more ping checks */
                    767:       if (victim)
                    768:        {
                    769:          victim->addr = addr;
                    770:          victim->time = now;
                    771:          victim->hash = hash;
                    772:        }
                    773:       return victim;
                    774:     }
                    775: }
                    776: 
1.1       misho     777: int address_allocate(struct dhcp_context *context,
                    778:                     struct in_addr *addrp, unsigned char *hwaddr, int hw_len, 
1.1.1.4   misho     779:                     struct dhcp_netid *netids, time_t now, int loopback)   
1.1       misho     780: {
                    781:   /* Find a free address: exclude anything in use and anything allocated to
                    782:      a particular hwaddr/clientid/hostname in our configuration.
                    783:      Try to return from contexts which match netids first. */
                    784: 
                    785:   struct in_addr start, addr;
                    786:   struct dhcp_context *c, *d;
                    787:   int i, pass;
                    788:   unsigned int j; 
                    789: 
                    790:   /* hash hwaddr: use the SDBM hashing algorithm.  Seems to give good
                    791:      dispersal even with similarly-valued "strings". */ 
                    792:   for (j = 0, i = 0; i < hw_len; i++)
1.1.1.3   misho     793:     j = hwaddr[i] + (j << 6) + (j << 16) - j;
1.1.1.4   misho     794: 
                    795:   /* j == 0 is marker */
                    796:   if (j == 0)
                    797:     j = 1;
1.1       misho     798:   
                    799:   for (pass = 0; pass <= 1; pass++)
                    800:     for (c = context; c; c = c->current)
                    801:       if (c->flags & (CONTEXT_STATIC | CONTEXT_PROXY))
                    802:        continue;
                    803:       else if (!match_netid(c->filter, netids, pass))
                    804:        continue;
                    805:       else
                    806:        {
                    807:          if (option_bool(OPT_CONSEC_ADDR))
                    808:            /* seed is largest extant lease addr in this context */
                    809:            start = lease_find_max_addr(c);
                    810:          else
                    811:            /* pick a seed based on hwaddr */
                    812:            start.s_addr = htonl(ntohl(c->start.s_addr) + 
                    813:                                 ((j + c->addr_epoch) % (1 + ntohl(c->end.s_addr) - ntohl(c->start.s_addr))));
                    814: 
                    815:          /* iterate until we find a free address. */
                    816:          addr = start;
                    817:          
                    818:          do {
                    819:            /* eliminate addresses in use by the server. */
                    820:            for (d = context; d; d = d->current)
                    821:              if (addr.s_addr == d->router.s_addr)
                    822:                break;
                    823: 
                    824:            /* Addresses which end in .255 and .0 are broken in Windows even when using 
                    825:               supernetting. ie dhcp-range=192.168.0.1,192.168.1.254,255,255,254.0
                    826:               then 192.168.0.255 is a valid IP address, but not for Windows as it's
                    827:               in the class C range. See  KB281579. We therefore don't allocate these 
                    828:               addresses to avoid hard-to-diagnose problems. Thanks Bill. */        
                    829:            if (!d &&
                    830:                !lease_find_by_addr(addr) && 
                    831:                !config_find_by_address(daemon->dhcp_conf, addr) &&
                    832:                (!IN_CLASSC(ntohl(addr.s_addr)) || 
                    833:                 ((ntohl(addr.s_addr) & 0xff) != 0xff && ((ntohl(addr.s_addr) & 0xff) != 0x0))))
                    834:              {
1.1.1.4   misho     835:                /* in consec-ip mode, skip addresses equal to
                    836:                   the number of addresses rejected by clients. This
                    837:                   should avoid the same client being offered the same
                    838:                   address after it has rjected it. */
                    839:                if (option_bool(OPT_CONSEC_ADDR) && c->addr_epoch)
                    840:                  c->addr_epoch--;
                    841:                else
1.1       misho     842:                  {
1.1.1.4   misho     843:                    struct ping_result *r;
                    844:                    
                    845:                    if ((r = do_icmp_ping(now, addr, j, loopback)))
                    846:                      {
                    847:                        /* consec-ip mode: we offered this address for another client
                    848:                           (different hash) recently, don't offer it to this one. */
                    849:                        if (!option_bool(OPT_CONSEC_ADDR) || r->hash == j)
                    850:                          {
                    851:                            *addrp = addr;
                    852:                            return 1;
                    853:                          }
                    854:                      }
                    855:                    else
1.1       misho     856:                      {
                    857:                        /* address in use: perturb address selection so that we are
                    858:                           less likely to try this address again. */
                    859:                        if (!option_bool(OPT_CONSEC_ADDR))
                    860:                          c->addr_epoch++;
                    861:                      }
                    862:                  }
                    863:              }
1.1.1.4   misho     864:            
1.1       misho     865:            addr.s_addr = htonl(ntohl(addr.s_addr) + 1);
                    866:            
                    867:            if (addr.s_addr == htonl(ntohl(c->end.s_addr) + 1))
                    868:              addr = c->start;
                    869:            
                    870:          } while (addr.s_addr != start.s_addr);
                    871:        }
                    872: 
                    873:   return 0;
                    874: }
                    875: 
                    876: void dhcp_read_ethers(void)
                    877: {
                    878:   FILE *f = fopen(ETHERSFILE, "r");
                    879:   unsigned int flags;
                    880:   char *buff = daemon->namebuff;
                    881:   char *ip, *cp;
                    882:   struct in_addr addr;
                    883:   unsigned char hwaddr[ETHER_ADDR_LEN];
                    884:   struct dhcp_config **up, *tmp;
                    885:   struct dhcp_config *config;
                    886:   int count = 0, lineno = 0;
                    887: 
                    888:   addr.s_addr = 0; /* eliminate warning */
                    889:   
                    890:   if (!f)
                    891:     {
                    892:       my_syslog(MS_DHCP | LOG_ERR, _("failed to read %s: %s"), ETHERSFILE, strerror(errno));
                    893:       return;
                    894:     }
                    895: 
                    896:   /* This can be called again on SIGHUP, so remove entries created last time round. */
                    897:   for (up = &daemon->dhcp_conf, config = daemon->dhcp_conf; config; config = tmp)
                    898:     {
                    899:       tmp = config->next;
                    900:       if (config->flags & CONFIG_FROM_ETHERS)
                    901:        {
                    902:          *up = tmp;
                    903:          /* cannot have a clid */
                    904:          if (config->flags & CONFIG_NAME)
                    905:            free(config->hostname);
                    906:          free(config->hwaddr);
                    907:          free(config);
                    908:        }
                    909:       else
                    910:        up = &config->next;
                    911:     }
                    912: 
                    913:   while (fgets(buff, MAXDNAME, f))
                    914:     {
                    915:       char *host = NULL;
                    916:       
                    917:       lineno++;
                    918:       
1.1.1.5 ! misho     919:       while (strlen(buff) > 0 && isspace((unsigned char)buff[strlen(buff)-1]))
1.1       misho     920:        buff[strlen(buff)-1] = 0;
                    921:       
                    922:       if ((*buff == '#') || (*buff == '+') || (*buff == 0))
                    923:        continue;
                    924:       
1.1.1.5 ! misho     925:       for (ip = buff; *ip && !isspace((unsigned char)*ip); ip++);
        !           926:       for(; *ip && isspace((unsigned char)*ip); ip++)
1.1       misho     927:        *ip = 0;
                    928:       if (!*ip || parse_hex(buff, hwaddr, ETHER_ADDR_LEN, NULL, NULL) != ETHER_ADDR_LEN)
                    929:        {
                    930:          my_syslog(MS_DHCP | LOG_ERR, _("bad line at %s line %d"), ETHERSFILE, lineno); 
                    931:          continue;
                    932:        }
                    933:       
                    934:       /* check for name or dotted-quad */
                    935:       for (cp = ip; *cp; cp++)
                    936:        if (!(*cp == '.' || (*cp >='0' && *cp <= '9')))
                    937:          break;
                    938:       
                    939:       if (!*cp)
                    940:        {
1.1.1.5 ! misho     941:          if (inet_pton(AF_INET, ip, &addr.s_addr) < 1)
1.1       misho     942:            {
                    943:              my_syslog(MS_DHCP | LOG_ERR, _("bad address at %s line %d"), ETHERSFILE, lineno); 
                    944:              continue;
                    945:            }
                    946: 
                    947:          flags = CONFIG_ADDR;
                    948:          
                    949:          for (config = daemon->dhcp_conf; config; config = config->next)
                    950:            if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr)
                    951:              break;
                    952:        }
                    953:       else 
                    954:        {
                    955:          int nomem;
                    956:          if (!(host = canonicalise(ip, &nomem)) || !legal_hostname(host))
                    957:            {
                    958:              if (!nomem)
                    959:                my_syslog(MS_DHCP | LOG_ERR, _("bad name at %s line %d"), ETHERSFILE, lineno); 
                    960:              free(host);
                    961:              continue;
                    962:            }
                    963:              
                    964:          flags = CONFIG_NAME;
                    965: 
                    966:          for (config = daemon->dhcp_conf; config; config = config->next)
                    967:            if ((config->flags & CONFIG_NAME) && hostname_isequal(config->hostname, host))
                    968:              break;
                    969:        }
                    970: 
                    971:       if (config && (config->flags & CONFIG_FROM_ETHERS))
                    972:        {
                    973:          my_syslog(MS_DHCP | LOG_ERR, _("ignoring %s line %d, duplicate name or IP address"), ETHERSFILE, lineno); 
                    974:          continue;
                    975:        }
                    976:        
                    977:       if (!config)
                    978:        { 
                    979:          for (config = daemon->dhcp_conf; config; config = config->next)
                    980:            {
                    981:              struct hwaddr_config *conf_addr = config->hwaddr;
                    982:              if (conf_addr && 
                    983:                  conf_addr->next == NULL && 
                    984:                  conf_addr->wildcard_mask == 0 &&
                    985:                  conf_addr->hwaddr_len == ETHER_ADDR_LEN &&
                    986:                  (conf_addr->hwaddr_type == ARPHRD_ETHER || conf_addr->hwaddr_type == 0) &&
                    987:                  memcmp(conf_addr->hwaddr, hwaddr, ETHER_ADDR_LEN) == 0)
                    988:                break;
                    989:            }
                    990:          
                    991:          if (!config)
                    992:            {
                    993:              if (!(config = whine_malloc(sizeof(struct dhcp_config))))
                    994:                continue;
                    995:              config->flags = CONFIG_FROM_ETHERS;
                    996:              config->hwaddr = NULL;
                    997:              config->domain = NULL;
                    998:              config->netid = NULL;
                    999:              config->next = daemon->dhcp_conf;
                   1000:              daemon->dhcp_conf = config;
                   1001:            }
                   1002:          
                   1003:          config->flags |= flags;
                   1004:          
                   1005:          if (flags & CONFIG_NAME)
                   1006:            {
                   1007:              config->hostname = host;
                   1008:              host = NULL;
                   1009:            }
                   1010:          
                   1011:          if (flags & CONFIG_ADDR)
                   1012:            config->addr = addr;
                   1013:        }
                   1014:       
                   1015:       config->flags |= CONFIG_NOCLID;
                   1016:       if (!config->hwaddr)
                   1017:        config->hwaddr = whine_malloc(sizeof(struct hwaddr_config));
                   1018:       if (config->hwaddr)
                   1019:        {
                   1020:          memcpy(config->hwaddr->hwaddr, hwaddr, ETHER_ADDR_LEN);
                   1021:          config->hwaddr->hwaddr_len = ETHER_ADDR_LEN;
                   1022:          config->hwaddr->hwaddr_type = ARPHRD_ETHER;
                   1023:          config->hwaddr->wildcard_mask = 0;
                   1024:          config->hwaddr->next = NULL;
                   1025:        }
                   1026:       count++;
                   1027:       
                   1028:       free(host);
                   1029: 
                   1030:     }
                   1031:   
                   1032:   fclose(f);
                   1033: 
                   1034:   my_syslog(MS_DHCP | LOG_INFO, _("read %s - %d addresses"), ETHERSFILE, count);
                   1035: }
                   1036: 
                   1037: 
                   1038: /* If we've not found a hostname any other way, try and see if there's one in /etc/hosts
                   1039:    for this address. If it has a domain part, that must match the set domain and
                   1040:    it gets stripped. The set of legal domain names is bigger than the set of legal hostnames
                   1041:    so check here that the domain name is legal as a hostname. 
                   1042:    NOTE: we're only allowed to overwrite daemon->dhcp_buff if we succeed. */
                   1043: char *host_from_dns(struct in_addr addr)
                   1044: {
                   1045:   struct crec *lookup;
                   1046: 
                   1047:   if (daemon->port == 0)
                   1048:     return NULL; /* DNS disabled. */
                   1049:   
1.1.1.4   misho    1050:   lookup = cache_find_by_addr(NULL, (union all_addr *)&addr, 0, F_IPV4);
1.1       misho    1051: 
                   1052:   if (lookup && (lookup->flags & F_HOSTS))
                   1053:     {
                   1054:       char *dot, *hostname = cache_get_name(lookup);
                   1055:       dot = strchr(hostname, '.');
                   1056:       
                   1057:       if (dot && strlen(dot+1) != 0)
                   1058:        {
                   1059:          char *d2 = get_domain(addr);
                   1060:          if (!d2 || !hostname_isequal(dot+1, d2))
                   1061:            return NULL; /* wrong domain */
                   1062:        }
                   1063: 
                   1064:       if (!legal_hostname(hostname))
                   1065:        return NULL;
                   1066:       
1.1.1.4   misho    1067:       safe_strncpy(daemon->dhcp_buff, hostname, 256);
1.1       misho    1068:       strip_hostname(daemon->dhcp_buff);
                   1069: 
                   1070:       return daemon->dhcp_buff;
                   1071:     }
                   1072:   
                   1073:   return NULL;
                   1074: }
                   1075: 
1.1.1.5 ! misho    1076: static int relay_upstream4(int iface_index, struct dhcp_packet *mess, size_t sz)
1.1.1.2   misho    1077: {
1.1.1.5 ! misho    1078:   struct in_addr giaddr = mess->giaddr;
        !          1079:   u8 hops = mess->hops;
        !          1080:   struct dhcp_relay *relay;
        !          1081: 
1.1.1.2   misho    1082:   if (mess->op != BOOTREQUEST)
                   1083:     return 0;
                   1084: 
1.1.1.5 ! misho    1085:   for (relay = daemon->relay4; relay; relay = relay->next)
        !          1086:     if (relay->iface_index != 0 && relay->iface_index == iface_index)
        !          1087:       break;
        !          1088: 
        !          1089:   /* No relay config. */
        !          1090:   if (!relay)
        !          1091:     return 0;
1.1.1.2   misho    1092:   
1.1.1.5 ! misho    1093:   for (; relay; relay = relay->next)
        !          1094:     if (relay->iface_index != 0 && relay->iface_index == iface_index)
        !          1095:       {
        !          1096:        union mysockaddr to;
        !          1097:        union all_addr from;
1.1.1.2   misho    1098: 
1.1.1.5 ! misho    1099:        mess->hops = hops;
        !          1100:        mess->giaddr = giaddr;
        !          1101:        
        !          1102:        if ((mess->hops++) > 20)
        !          1103:          continue;
        !          1104:        
        !          1105:        /* source address == relay address */
        !          1106:        from.addr4 = relay->local.addr4;
1.1       misho    1107: 
1.1.1.5 ! misho    1108:        /* already gatewayed ? */
        !          1109:        if (giaddr.s_addr)
        !          1110:          {
        !          1111:            /* if so check if by us, to stomp on loops. */
        !          1112:            if (giaddr.s_addr == relay->local.addr4.s_addr)
        !          1113:              continue;
        !          1114:          }
        !          1115:        else
        !          1116:          {
        !          1117:            /* plug in our address */
        !          1118:            mess->giaddr.s_addr = relay->local.addr4.s_addr;
        !          1119:          }
        !          1120:        
        !          1121:        to.sa.sa_family = AF_INET;
        !          1122:        to.in.sin_addr = relay->server.addr4;
        !          1123:        to.in.sin_port = htons(relay->port);
        !          1124:        
        !          1125:        /* Broadcasting to server. */
        !          1126:        if (relay->server.addr4.s_addr == 0)
        !          1127:          {
        !          1128:            struct ifreq ifr;
        !          1129:            
        !          1130:            if (relay->interface)
        !          1131:              safe_strncpy(ifr.ifr_name, relay->interface, IF_NAMESIZE);
        !          1132:            
        !          1133:            if (!relay->interface || strchr(relay->interface, '*') ||
        !          1134:                ioctl(daemon->dhcpfd, SIOCGIFBRDADDR, &ifr) == -1)
        !          1135:              {
        !          1136:                my_syslog(MS_DHCP | LOG_ERR, _("Cannot broadcast DHCP relay via interface %s"), relay->interface);
        !          1137:                continue;
        !          1138:              }
        !          1139:            
        !          1140:            to.in.sin_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
        !          1141:          }
        !          1142:        
        !          1143: #ifdef HAVE_DUMPFILE
1.1.1.2   misho    1144:        {
1.1.1.5 ! misho    1145:          union mysockaddr fromsock;
        !          1146:          fromsock.in.sin_port = htons(daemon->dhcp_server_port);
        !          1147:          fromsock.in.sin_addr = from.addr4;
        !          1148:          fromsock.sa.sa_family = AF_INET;
        !          1149: 
        !          1150:          dump_packet_udp(DUMP_DHCP, (void *)mess, sz, &fromsock, &to, -1);
1.1.1.2   misho    1151:        }
1.1.1.5 ! misho    1152: #endif
        !          1153:        
        !          1154:         send_from(daemon->dhcpfd, 0, (char *)mess, sz, &to, &from, 0);
        !          1155:         
        !          1156:         if (option_bool(OPT_LOG_OPTS))
        !          1157:           {
        !          1158:             inet_ntop(AF_INET, &relay->local, daemon->addrbuff, ADDRSTRLEN);
        !          1159:             if (relay->server.addr4.s_addr == 0)
        !          1160:               snprintf(daemon->dhcp_buff2, DHCP_BUFF_SZ, _("broadcast via %s"), relay->interface);
        !          1161:             else
        !          1162:               inet_ntop(AF_INET, &relay->server.addr4, daemon->dhcp_buff2, DHCP_BUFF_SZ);
        !          1163:             my_syslog(MS_DHCP | LOG_INFO, _("DHCP relay at %s -> %s"), daemon->addrbuff, daemon->dhcp_buff2);
        !          1164:           }
        !          1165:       }
1.1.1.2   misho    1166:   
                   1167:   return 1;
                   1168: }
                   1169: 
                   1170: 
                   1171: static struct dhcp_relay *relay_reply4(struct dhcp_packet *mess, char *arrival_interface)
                   1172: {
                   1173:   struct dhcp_relay *relay;
                   1174: 
                   1175:   if (mess->giaddr.s_addr == 0 || mess->op != BOOTREPLY)
                   1176:     return NULL;
                   1177: 
                   1178:   for (relay = daemon->relay4; relay; relay = relay->next)
                   1179:     {
1.1.1.4   misho    1180:       if (mess->giaddr.s_addr == relay->local.addr4.s_addr)
1.1.1.2   misho    1181:        {
                   1182:          if (!relay->interface || wildcard_match(relay->interface, arrival_interface))
                   1183:            return relay->iface_index != 0 ? relay : NULL;
                   1184:        }
                   1185:     }
                   1186:   
                   1187:   return NULL;  
                   1188: }     
                   1189: 
                   1190: #endif

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