/* dispatch.c Network input dispatcher... */ /* * Copyright (c) 1995, 1996, 1997, 1998, 1999 * The Internet Software Consortium. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of The Internet Software Consortium nor the names * of its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. */ #include "dhcpd.h" #include #include #include #include /* Most boxes has less than 16 interfaces, so this might be a good guess. */ #define INITIAL_IFREQ_COUNT 16 struct interface_info *interfaces, *dummy_interfaces, *fallback_interface; struct protocol *protocols; struct timeout *timeouts; static struct timeout *free_timeouts; static int interfaces_invalidated; void (*bootp_packet_handler) PROTO ((struct interface_info *, struct dhcp_packet *, int, unsigned int, struct iaddr, struct hardware *)); static int interface_status(struct interface_info *ifinfo); int quiet_interface_discovery; /* Use the SIOCGIFCONF ioctl to get a list of all the attached interfaces. For each interface that's of type INET and not the loopback interface, register that interface with the network I/O software, figure out what subnet it's on, and add it to the list of interfaces. */ void discover_interfaces (state) int state; { struct interface_info *tmp; struct interface_info *last, *next; int sock; struct subnet *subnet; struct shared_network *share; struct sockaddr_in foo; int ir; struct ifreq *tif; struct ifaddrs *ifap, *ifa; #ifdef ALIAS_NAMES_PERMUTED char *s; #endif /* Create an unbound datagram socket to do the SIOCGIFADDR ioctl on. */ if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) error ("Can't create addrlist socket"); if (getifaddrs(&ifap) != 0) error ("getifaddrs failed"); /* If we already have a list of interfaces, and we're running as a DHCP server, the interfaces were requested. */ if (interfaces && (state == DISCOVER_SERVER || state == DISCOVER_RELAY || state == DISCOVER_REQUESTED)) ir = 0; else if (state == DISCOVER_UNCONFIGURED) ir = INTERFACE_REQUESTED | INTERFACE_AUTOMATIC; else ir = INTERFACE_REQUESTED; /* Cycle through the list of interfaces looking for IP addresses. */ for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { /* See if this is the sort of interface we want to deal with. Skip loopback, point-to-point and down interfaces, except don't skip down interfaces if we're trying to get a list of configurable interfaces. */ if ((ifa->ifa_flags & IFF_LOOPBACK) || (ifa->ifa_flags & IFF_POINTOPOINT) || (!(ifa->ifa_flags & IFF_UP) && state != DISCOVER_UNCONFIGURED)) continue; /* See if we've seen an interface that matches this one. */ for (tmp = interfaces; tmp; tmp = tmp -> next) if (!strcmp (tmp -> name, ifa -> ifa_name)) break; /* If there isn't already an interface by this name, allocate one. */ if (!tmp) { tmp = ((struct interface_info *) dmalloc (sizeof *tmp, "discover_interfaces")); if (!tmp) error ("Insufficient memory to %s %s", "record interface", ifa -> ifa_name); strlcpy (tmp -> name, ifa -> ifa_name, sizeof(tmp->name)); tmp -> next = interfaces; tmp -> flags = ir; tmp -> noifmedia = tmp -> dead = tmp->errors = 0; interfaces = tmp; } /* If we have the capability, extract link information and record it in a linked list. */ if (ifa -> ifa_addr->sa_family == AF_LINK) { struct sockaddr_dl *foo = ((struct sockaddr_dl *) (ifa -> ifa_addr)); tmp -> hw_address.hlen = foo -> sdl_alen; tmp -> hw_address.htype = HTYPE_ETHER; /* XXX */ memcpy (tmp -> hw_address.haddr, LLADDR (foo), foo -> sdl_alen); } else if (ifa -> ifa_addr->sa_family == AF_INET) { struct iaddr addr; /* Get a pointer to the address... */ bcopy(ifa->ifa_addr, &foo, sizeof(foo)); /* We don't want the loopback interface. */ if (foo.sin_addr.s_addr == htonl (INADDR_LOOPBACK)) continue; /* If this is the first real IP address we've found, keep a pointer to ifreq structure in which we found it. */ if (!tmp -> ifp) { int len = (IFNAMSIZ + ifa -> ifa_addr->sa_len); tif = (struct ifreq *)malloc (len); if (!tif) error ("no space to remember ifp."); strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); memcpy(&tif->ifr_addr, ifa->ifa_addr, ifa->ifa_addr->sa_len); tmp -> ifp = tif; tmp -> primary_address = foo.sin_addr; } /* Grab the address... */ addr.len = 4; memcpy (addr.iabuf, &foo.sin_addr.s_addr, addr.len); /* If there's a registered subnet for this address, connect it together... */ if ((subnet = find_subnet (addr))) { /* If this interface has multiple aliases on the same subnet, ignore all but the first we encounter. */ if (!subnet -> interface) { subnet -> interface = tmp; subnet -> interface_address = addr; } else if (subnet -> interface != tmp) { warn ("Multiple %s %s: %s %s", "interfaces match the", "same subnet", subnet -> interface -> name, tmp -> name); } share = subnet -> shared_network; if (tmp -> shared_network && tmp -> shared_network != share) { warn ("Interface %s matches %s", tmp -> name, "multiple shared networks"); } else { tmp -> shared_network = share; } if (!share -> interface) { share -> interface = tmp; } else if (share -> interface != tmp) { warn ("Multiple %s %s: %s %s", "interfaces match the", "same shared network", share -> interface -> name, tmp -> name); } } } } /* Now cycle through all the interfaces we found, looking for hardware addresses. */ /* If we're just trying to get a list of interfaces that we might be able to configure, we can quit now. */ if (state == DISCOVER_UNCONFIGURED) return; /* Weed out the interfaces that did not have IP addresses. */ last = (struct interface_info *)0; for (tmp = interfaces; tmp; tmp = next) { next = tmp -> next; if ((tmp -> flags & INTERFACE_AUTOMATIC) && state == DISCOVER_REQUESTED) tmp -> flags &= ~(INTERFACE_AUTOMATIC | INTERFACE_REQUESTED); if (!tmp -> ifp || !(tmp -> flags & INTERFACE_REQUESTED)) { if ((tmp -> flags & INTERFACE_REQUESTED) != ir) error ("%s: not found", tmp -> name); if (!last) interfaces = interfaces -> next; else last -> next = tmp -> next; /* Remember the interface in case we need to know about it later. */ tmp -> next = dummy_interfaces; dummy_interfaces = tmp; continue; } last = tmp; memcpy (&foo, &tmp -> ifp -> ifr_addr, sizeof tmp -> ifp -> ifr_addr); /* We must have a subnet declaration for each interface. */ if (!tmp -> shared_network && (state == DISCOVER_SERVER)) { warn ("No subnet declaration for %s (%s).", tmp -> name, inet_ntoa (foo.sin_addr)); warn ("Please write a subnet declaration in your %s", "dhcpd.conf file for the"); error ("network segment to which interface %s %s", tmp -> name, "is attached."); } /* Find subnets that don't have valid interface addresses... */ for (subnet = (tmp -> shared_network ? tmp -> shared_network -> subnets : (struct subnet *)0); subnet; subnet = subnet -> next_sibling) { if (!subnet -> interface_address.len) { /* Set the interface address for this subnet to the first address we found. */ subnet -> interface_address.len = 4; memcpy (subnet -> interface_address.iabuf, &foo.sin_addr.s_addr, 4); } } /* Register the interface... */ if_register_receive (tmp); if_register_send (tmp); } /* Now register all the remaining interfaces as protocols. */ for (tmp = interfaces; tmp; tmp = tmp -> next) { add_protocol (tmp -> name, tmp -> rfdesc, got_one, tmp); } close (sock); freeifaddrs(ifap); maybe_setup_fallback (); } struct interface_info *setup_fallback () { fallback_interface = ((struct interface_info *) dmalloc (sizeof *fallback_interface, "discover_interfaces")); if (!fallback_interface) error ("Insufficient memory to record fallback interface."); memset (fallback_interface, 0, sizeof *fallback_interface); strlcpy (fallback_interface -> name, "fallback", IFNAMSIZ); fallback_interface -> shared_network = new_shared_network ("parse_statement"); if (!fallback_interface -> shared_network) error ("No memory for shared subnet"); memset (fallback_interface -> shared_network, 0, sizeof (struct shared_network)); fallback_interface -> shared_network -> name = "fallback-net"; return fallback_interface; } void reinitialize_interfaces () { struct interface_info *ip; for (ip = interfaces; ip; ip = ip -> next) { if_reinitialize_receive (ip); if_reinitialize_send (ip); } if (fallback_interface) if_reinitialize_send (fallback_interface); interfaces_invalidated = 1; } /* Wait for packets to come in using poll(). When a packet comes in, call receive_packet to receive the packet and possibly strip hardware addressing information from it, and then call through the bootp_packet_handler hook to try to do something with it. */ void dispatch () { struct protocol *l; int nfds = 0; struct pollfd *fds; int count; int i; time_t howlong; int to_msec; nfds = 0; for (l = protocols; l; l = l -> next) { ++nfds; } fds = (struct pollfd *)malloc ((nfds) * sizeof (struct pollfd)); if (fds == NULL) error ("Can't allocate poll structures."); do { /* Call any expired timeouts, and then if there's still a timeout registered, time out the select call then. */ another: if (timeouts) { struct timeout *t; if (timeouts -> when <= cur_time) { t = timeouts; timeouts = timeouts -> next; (*(t -> func)) (t -> what); t -> next = free_timeouts; free_timeouts = t; goto another; } /* * Figure timeout in milliseconds, and check for * potential overflow, so we can cram into an int * for poll, while not polling with a negative * timeout and blocking indefinetely. */ howlong = timeouts -> when - cur_time; if (howlong > INT_MAX / 1000) howlong = INT_MAX / 1000; to_msec = howlong * 1000; } else to_msec = -1; /* Set up the descriptors to be polled. */ i = 0; for (l = protocols; l; l = l -> next) { struct interface_info *ip = l -> local; if (ip && (l->handler != got_one || !ip->dead)) { fds [i].fd = l -> fd; fds [i].events = POLLIN; fds [i].revents = 0; ++i; } } if (i == 0) error("No live interfaces to poll on - exiting."); /* Wait for a packet or a timeout... XXX */ count = poll (fds, nfds, to_msec); /* Not likely to be transitory... */ if (count == -1) { if (errno == EAGAIN || errno == EINTR) { GET_TIME (&cur_time); continue; } else error ("poll: %m"); } /* Get the current time... */ GET_TIME (&cur_time); i = 0; for (l = protocols; l; l = l -> next) { struct interface_info *ip; ip = l->local; if ((fds [i].revents & POLLIN)) { fds [i].revents = 0; if (ip && (l->handler != got_one || !ip->dead)) (*(l -> handler)) (l); if (interfaces_invalidated) break; } ++i; } interfaces_invalidated = 0; } while (1); } void got_one (l) struct protocol *l; { struct sockaddr_in from; struct hardware hfrom; struct iaddr ifrom; size_t result; union { unsigned char packbuf [4095]; /* Packet input buffer. Must be as large as largest possible MTU. */ struct dhcp_packet packet; } u; struct interface_info *ip = l -> local; if ((result = receive_packet (ip, u.packbuf, sizeof u, &from, &hfrom)) == -1) { warn ("receive_packet failed on %s: %s", ip -> name, strerror(errno)); ip->errors++; if ((! interface_status(ip)) || (ip->noifmedia && ip->errors > 20)) { /* our interface has gone away. */ warn("Interface %s appears to no longer be valid", ip->name); ip->dead = 1; interfaces_invalidated = 1; } return; } if (result == 0) return; if (bootp_packet_handler) { ifrom.len = 4; memcpy (ifrom.iabuf, &from.sin_addr, ifrom.len); (*bootp_packet_handler) (ip, &u.packet, result, from.sin_port, ifrom, &hfrom); } } int interface_status(struct interface_info *ifinfo) { char * ifname = ifinfo->name; int ifsock = ifinfo->rfdesc; struct ifreq ifr; struct ifmediareq ifmr; /* get interface flags */ memset(&ifr, 0, sizeof(ifr)); strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); goto inactive; } /* * if one of UP and RUNNING flags is dropped, * the interface is not active. */ if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) { goto inactive; } /* Next, check carrier on the interface, if possible */ if (ifinfo->noifmedia) goto active; memset(&ifmr, 0, sizeof(ifmr)); strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { if (errno != EINVAL) { syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", ifname); ifinfo->noifmedia = 1; goto active; } /* * EINVAL (or ENOTTY) simply means that the interface * does not support the SIOCGIFMEDIA ioctl. We regard it alive. */ ifinfo->noifmedia = 1; goto active; } if (ifmr.ifm_status & IFM_AVALID) { switch(ifmr.ifm_active & IFM_NMASK) { case IFM_ETHER: if (ifmr.ifm_status & IFM_ACTIVE) goto active; else goto inactive; break; default: goto inactive; } } inactive: return(0); active: return(1); } int locate_network (packet) struct packet *packet; { struct iaddr ia; /* If this came through a gateway, find the corresponding subnet... */ if (packet -> raw -> giaddr.s_addr) { struct subnet *subnet; ia.len = 4; memcpy (ia.iabuf, &packet -> raw -> giaddr, 4); subnet = find_subnet (ia); if (subnet) packet -> shared_network = subnet -> shared_network; else packet -> shared_network = (struct shared_network *)0; } else { packet -> shared_network = packet -> interface -> shared_network; } if (packet -> shared_network) return 1; return 0; } void add_timeout (when, where, what) TIME when; void (*where) PROTO ((void *)); void *what; { struct timeout *t, *q; /* See if this timeout supersedes an existing timeout. */ t = (struct timeout *)0; for (q = timeouts; q; q = q -> next) { if (q -> func == where && q -> what == what) { if (t) t -> next = q -> next; else timeouts = q -> next; break; } t = q; } /* If we didn't supersede a timeout, allocate a timeout structure now. */ if (!q) { if (free_timeouts) { q = free_timeouts; free_timeouts = q -> next; q -> func = where; q -> what = what; } else { q = (struct timeout *)malloc (sizeof (struct timeout)); if (!q) error ("Can't allocate timeout structure!"); q -> func = where; q -> what = what; } } q -> when = when; /* Now sort this timeout into the timeout list. */ /* Beginning of list? */ if (!timeouts || timeouts -> when > q -> when) { q -> next = timeouts; timeouts = q; return; } /* Middle of list? */ for (t = timeouts; t -> next; t = t -> next) { if (t -> next -> when > q -> when) { q -> next = t -> next; t -> next = q; return; } } /* End of list. */ t -> next = q; q -> next = (struct timeout *)0; } void cancel_timeout (where, what) void (*where) PROTO ((void *)); void *what; { struct timeout *t, *q; /* Look for this timeout on the list, and unlink it if we find it. */ t = (struct timeout *)0; for (q = timeouts; q; q = q -> next) { if (q -> func == where && q -> what == what) { if (t) t -> next = q -> next; else timeouts = q -> next; break; } t = q; } /* If we found the timeout, put it on the free list. */ if (q) { q -> next = free_timeouts; free_timeouts = q; } } /* Add a protocol to the list of protocols... */ void add_protocol (name, fd, handler, local) char *name; int fd; void (*handler) PROTO ((struct protocol *)); void *local; { struct protocol *p; p = (struct protocol *)malloc (sizeof *p); if (!p) error ("can't allocate protocol struct for %s", name); p -> fd = fd; p -> handler = handler; p -> local = local; p -> next = protocols; protocols = p; } void remove_protocol (proto) struct protocol *proto; { struct protocol *p, *next, *prev; prev = (struct protocol *)0; for (p = protocols; p; p = next) { next = p -> next; if (p == proto) { if (prev) prev -> next = p -> next; else protocols = p -> next; free (p); } } }