/* $OpenBSD: dispatch.c,v 1.10 2016/02/07 00:49:28 krw Exp $ */ /* * Copyright 2004 Henning Brauer * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "dhcp.h" #include "dhcpd.h" struct protocol *protocols; struct timeout *timeouts; static struct timeout *free_timeouts; static int interfaces_invalidated; void (*bootp_packet_handler)(struct interface_info *, struct dhcp_packet *, int, unsigned int, struct iaddr, struct hardware *); static int interface_status(struct interface_info *ifinfo); /* * 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(struct interface_info *iface) { struct sockaddr_in foo; struct ifaddrs *ifap, *ifa; struct ifreq *tif; if (getifaddrs(&ifap) != 0) error("getifaddrs failed"); for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { if ((ifa->ifa_flags & IFF_LOOPBACK) || (ifa->ifa_flags & IFF_POINTOPOINT) || (!(ifa->ifa_flags & IFF_UP))) continue; if (strcmp(iface->name, ifa->ifa_name)) continue; /* * 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; struct if_data *ifi = (struct if_data *)ifa->ifa_data; iface->index = foo->sdl_index; iface->hw_address.hlen = foo->sdl_alen; if (ifi->ifi_type == IFT_ENC) iface->hw_address.htype = HTYPE_IPSEC_TUNNEL; else iface->hw_address.htype = HTYPE_ETHER; /* XXX */ memcpy(iface->hw_address.haddr, LLADDR(foo), foo->sdl_alen); } else if (ifa->ifa_addr->sa_family == AF_INET) { struct iaddr addr; memcpy(&foo, ifa->ifa_addr, sizeof(foo)); if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) continue; if (!iface->ifp) { int len = IFNAMSIZ + ifa->ifa_addr->sa_len; if ((tif = malloc(len)) == NULL) 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); iface->ifp = tif; iface->primary_address = foo.sin_addr; } addr.len = 4; memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); } } if (!iface->ifp) error("%s: not found", iface->name); /* Register the interface... */ if_register_receive(iface); if_register_send(iface); add_protocol(iface->name, iface->rfdesc, got_one, iface); 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 call through the * bootp_packet_handler hook to try to do something with it. */ void dispatch(void) { int count, i, to_msec, nfds = 0; struct protocol *l; struct pollfd *fds; time_t howlong; nfds = 0; for (l = protocols; l; l = l->next) nfds++; fds = calloc(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) { if (timeouts->when <= cur_time) { struct 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. */ 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) { time(&cur_time); continue; } else error("poll: %m"); } /* Get the current time... */ time(&cur_time); i = 0; for (l = protocols; l; l = l->next) { struct interface_info *ip = l->local; if ((fds[i].revents & (POLLIN | POLLHUP))) { 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(struct protocol *l) { struct sockaddr_in from; struct hardware hfrom; struct iaddr ifrom; size_t result; union { /* * Packet input buffer. Must be as large as largest * possible MTU. */ unsigned char packbuf[4095]; struct dhcp_packet packet; } u; struct interface_info *ip = l->local; 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; 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) == -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); } /* 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 = 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; 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); } } }