/* $OpenBSD: dispatch.c,v 1.34 2014/10/08 04:26:07 deraadt Exp $ */ /* * 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 "sync.h" #include #include #include #include extern int syncfd; struct interface_info *interfaces; struct protocol *protocols; struct dhcpd_timeout *timeouts; static struct dhcpd_timeout *free_timeouts; static int interfaces_invalidated; static int interface_status(struct interface_info *ifinfo); int get_rdomain(char *); /* Use getifaddrs() 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(int *rdomain) { struct interface_info *tmp; struct interface_info *last, *next; struct subnet *subnet; struct shared_network *share; struct sockaddr_in foo; int ir = 0, ird; struct ifreq *tif; struct ifaddrs *ifap, *ifa; if (getifaddrs(&ifap) != 0) error("getifaddrs failed"); /* * If we already have a list of interfaces, the interfaces were * requested. */ if (interfaces != NULL) ir = 1; else /* must specify an interface when rdomains are used */ *rdomain = 0; /* 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)) || (!(ifa->ifa_flags & IFF_BROADCAST))) 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 we are looking for specific interfaces, ignore others. */ if (tmp == NULL && ir) continue; ird = get_rdomain(ifa->ifa_name); if (*rdomain == -1) *rdomain = ird; else if (*rdomain != ird && ir) error("Interface %s is not in rdomain %d", tmp->name, *rdomain); else if (*rdomain != ird && !ir) continue; /* If there isn't already an interface by this name, allocate one. */ if (tmp == NULL) { tmp = calloc(1, sizeof *tmp); 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->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->index = foo->sdl_index; 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... */ memcpy(&foo, ifa->ifa_addr, 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) { warning("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) { warning("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) { warning("Multiple %s %s: %s %s", "interfaces match the", "same shared network", share->interface->name, tmp->name); } } } } /* Discard interfaces we can't listen on. */ last = NULL; for (tmp = interfaces; tmp; tmp = next) { next = tmp->next; if (!tmp->ifp) { warning("Can't listen on %s - it has no IP address.", tmp->name); /* Remove tmp from the list of interfaces. */ if (!last) interfaces = interfaces->next; else last->next = tmp->next; continue; } memcpy(&foo, &tmp->ifp->ifr_addr, sizeof tmp->ifp->ifr_addr); if (!tmp->shared_network) { warning("Can't listen on %s - dhcpd.conf has no subnet " "declaration for %s.", tmp->name, inet_ntoa(foo.sin_addr)); /* Remove tmp from the list of interfaces. */ if (!last) interfaces = interfaces->next; else last->next = tmp->next; continue; } last = tmp; /* Find subnets that don't have valid interface addresses. */ for (subnet = (tmp->shared_network ? tmp->shared_network->subnets : NULL); 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); note("Listening on %s (%s).", tmp->name, inet_ntoa(foo.sin_addr)); } if (interfaces == NULL) error("No interfaces to listen on."); /* Now register all the remaining interfaces as protocols. */ for (tmp = interfaces; tmp; tmp = tmp->next) add_protocol(tmp->name, tmp->rfdesc, got_one, tmp); freeifaddrs(ifap); } /* * 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 process it in do_packet. */ void dispatch(void) { int nfds, i, to_msec; struct protocol *l; static struct pollfd *fds; static int nfds_max; time_t howlong; for (nfds = 0, l = protocols; l; l = l->next) nfds++; if (syncfd != -1) nfds++; if (nfds > nfds_max) { fds = reallocarray(fds, nfds, sizeof(struct pollfd)); if (fds == NULL) error("Can't allocate poll structures."); nfds_max = nfds; } for (;;) { /* * Call any expired timeouts, and then if there's * still a timeout registered, time out the poll * call then. */ time(&cur_time); another: if (timeouts) { if (timeouts->when <= cur_time) { struct dhcpd_timeout *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 indefinitely. */ 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. */ for (i = 0, 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; ++i; } } if (i == 0) error("No live interfaces to poll on - exiting."); if (syncfd != -1) { /* add syncer */ fds[i].fd = syncfd; fds[i].events = POLLIN; } /* Wait for a packet or a timeout... */ switch (poll(fds, nfds, to_msec)) { case -1: if (errno != EAGAIN && errno != EINTR) error("poll: %m"); /* FALLTHROUGH */ case 0: continue; /* no packets */ } time(&cur_time); for (i = 0, l = protocols; l; l = l->next) { struct interface_info *ip = l->local; if ((fds[i].revents & (POLLIN | POLLHUP))) { if (ip && (l->handler != got_one || !ip->dead)) (*(l->handler))(l); if (interfaces_invalidated) break; } ++i; } if ((syncfd != -1) && (fds[i].revents & (POLLIN | POLLHUP))) sync_recv(); interfaces_invalidated = 0; } } void got_one(struct protocol *l) { struct sockaddr_in from; struct hardware hfrom; struct iaddr ifrom; ssize_t result; union { unsigned char packbuf[4095]; struct dhcp_packet packet; } u; struct interface_info *ip = l->local; bzero(&u, sizeof(u)); if ((result = receive_packet(ip, u.packbuf, sizeof u, &from, &hfrom)) == -1) { warning("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. */ warning("Interface %s no longer appears valid.", ip->name); ip->dead = 1; interfaces_invalidated = 1; close(l->fd); remove_protocol(l); free(ip); } return; } if (result == 0) return; ifrom.len = 4; memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); do_packet(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) == -1) { 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) == -1) { 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(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 = NULL; } else { packet->shared_network = packet->interface->shared_network; } if (packet->shared_network) return 1; return 0; } void add_timeout(time_t when, void (*where)(void *), void *what) { struct dhcpd_timeout *t, *q; /* See if this timeout supersedes an existing timeout. */ t = NULL; 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 dhcpd_timeout *)malloc(sizeof (struct dhcpd_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 = NULL; } void cancel_timeout(void (*where)(void *), void *what) { struct dhcpd_timeout *t, *q; /* Look for this timeout on the list, and unlink it if we find it. */ t = NULL; 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(char *name, int fd, void (*handler)(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(struct protocol *proto) { struct protocol *p, *next, *prev = NULL; for (p = protocols; p; p = next) { next = p->next; if (p == proto) { if (prev) prev->next = p->next; else protocols = p->next; free(p); } } } int get_rdomain(char *name) { int rv = 0, s; struct ifreq ifr; if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) error("get_rdomain socket: %m"); bzero(&ifr, sizeof(ifr)); strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name)); if (ioctl(s, SIOCGIFRDOMAIN, (caddr_t)&ifr) != -1) rv = ifr.ifr_rdomainid; close(s); return rv; }