/* $NetBSD: socket.c,v 1.2.6.1 2024/02/29 11:39:17 martin Exp $ */ /* socket.c BSD socket interface code... */ /* * Copyright (C) 2004-2022 Internet Systems Consortium, Inc. ("ISC") * Copyright (c) 1995-2003 by Internet Software Consortium * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Internet Systems Consortium, Inc. * PO Box 360 * Newmarket, NH 03857 USA * * https://www.isc.org/ * */ #include __RCSID("$NetBSD: socket.c,v 1.2.6.1 2024/02/29 11:39:17 martin Exp $"); /* SO_BINDTODEVICE support added by Elliot Poger (poger@leland.stanford.edu). * This sockopt allows a socket to be bound to a particular interface, * thus enabling the use of DHCPD on a multihomed host. * If SO_BINDTODEVICE is defined in your system header files, the use of * this sockopt will be automatically enabled. * I have implemented it under Linux; other systems should be doable also. */ #include "dhcpd.h" #include #include #include #include #include #if defined(sun) && defined(USE_V4_PKTINFO) #include #include #include #include #include #endif #ifdef USE_SOCKET_FALLBACK # if !defined (USE_SOCKET_SEND) # define if_register_send if_register_fallback # define send_packet send_fallback # define if_reinitialize_send if_reinitialize_fallback # endif #endif #if defined(DHCPv6) /* * XXX: this is gross. we need to go back and overhaul the API for socket * handling. */ static int no_global_v6_socket = 0; static unsigned int global_v6_socket_references = 0; static int global_v6_socket = -1; #if defined(RELAY_PORT) static unsigned int relay_port_v6_socket_references = 0; static int relay_port_v6_socket = -1; #endif static void if_register_multicast(struct interface_info *info); #endif /* * We can use a single socket for AF_INET (similar to AF_INET6) on all * interfaces configured for DHCP if the system has support for IP_PKTINFO * and IP_RECVPKTINFO (for example Solaris 11). */ #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) static unsigned int global_v4_socket_references = 0; static int global_v4_socket = -1; #endif /* * If we can't bind() to a specific interface, then we can only have * a single socket. This variable insures that we don't try to listen * on two sockets. */ #if !defined(SO_BINDTODEVICE) && !defined(USE_FALLBACK) static int once = 0; #endif /* !defined(SO_BINDTODEVICE) && !defined(USE_FALLBACK) */ /* Reinitializes the specified interface after an address change. This is not required for packet-filter APIs. */ #if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK) void if_reinitialize_send (info) struct interface_info *info; { #if 0 #ifndef USE_SOCKET_RECEIVE once = 0; close (info -> wfdesc); #endif if_register_send (info); #endif } #endif #ifdef USE_SOCKET_RECEIVE void if_reinitialize_receive (info) struct interface_info *info; { #if 0 once = 0; close (info -> rfdesc); if_register_receive (info); #endif } #endif #if defined (USE_SOCKET_SEND) || \ defined (USE_SOCKET_RECEIVE) || \ defined (USE_SOCKET_FALLBACK) /* Generic interface registration routine... */ int if_register_socket(struct interface_info *info, int family, int *do_multicast, struct in6_addr *linklocal6) { struct sockaddr_storage name; int name_len; int sock; int flag; int domain; #ifdef DHCPv6 struct sockaddr_in6 *addr6; #endif struct sockaddr_in *addr; /* INSIST((family == AF_INET) || (family == AF_INET6)); */ #if !defined(SO_BINDTODEVICE) && !defined(USE_FALLBACK) /* Make sure only one interface is registered. */ if (once) { log_fatal ("The standard socket API can only support %s", "hosts with a single network interface."); } once = 1; #endif /* * Set up the address we're going to bind to, depending on the * address family. */ memset(&name, 0, sizeof(name)); switch (family) { #ifdef DHCPv6 case AF_INET6: addr6 = (struct sockaddr_in6 *)&name; addr6->sin6_family = AF_INET6; addr6->sin6_port = *libdhcp_callbacks.local_port; #if defined(RELAY_PORT) if (relay_port && ((info->flags & INTERFACE_STREAMS) == INTERFACE_UPSTREAM)) addr6->sin6_port = relay_port; #endif /* A server feature */ if (bind_local_address6) { memcpy(&addr6->sin6_addr, &local_address6, sizeof(addr6->sin6_addr)); } /* A client feature */ if (linklocal6) { memcpy(&addr6->sin6_addr, linklocal6, sizeof(addr6->sin6_addr)); } if (IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) { addr6->sin6_scope_id = if_nametoindex(info->name); } #ifdef HAVE_SA_LEN addr6->sin6_len = sizeof(*addr6); #endif name_len = sizeof(*addr6); domain = PF_INET6; if ((info->flags & INTERFACE_STREAMS) == INTERFACE_UPSTREAM) { *do_multicast = 0; } break; #endif /* DHCPv6 */ case AF_INET: default: addr = (struct sockaddr_in *)&name; addr->sin_family = AF_INET; addr->sin_port = relay_port ? relay_port : *libdhcp_callbacks.local_port; memcpy(&addr->sin_addr, &local_address, sizeof(addr->sin_addr)); #ifdef HAVE_SA_LEN addr->sin_len = sizeof(*addr); #endif name_len = sizeof(*addr); domain = PF_INET; break; } /* Make a socket... */ sock = socket(domain, SOCK_DGRAM, IPPROTO_UDP); if (sock < 0) { log_fatal("Can't create dhcp socket for %s: %m", info->name); } /* Set the REUSEADDR option so that we don't fail to start if we're being restarted. */ flag = 1; if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&flag, sizeof(flag)) < 0) { log_fatal("Can't set SO_REUSEADDR on dhcp socket for" " %s: %m", info->name); } /* Set the BROADCAST option so that we can broadcast DHCP responses. We shouldn't do this for fallback devices, and we can detect that a device is a fallback because it has no ifp structure. */ if (info->ifp && (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&flag, sizeof(flag)) < 0)) { log_fatal("Can't set SO_BROADCAST on dhcp socket for" " %s: %m", info->name); } #if defined(DHCPv6) && defined(SO_REUSEPORT) /* * We only set SO_REUSEPORT on AF_INET6 sockets, so that multiple * daemons can bind to their own sockets and get data for their * respective interfaces. This does not (and should not) affect * DHCPv4 sockets; we can't yet support BSD sockets well, much * less multiple sockets. Make sense only with multicast. * RedHat defines SO_REUSEPORT with a kernel which does not support * it and returns ENOPROTOOPT so in this case ignore the error. */ if ((local_family == AF_INET6) && *do_multicast) { flag = 1; if ((setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (char *)&flag, sizeof(flag)) < 0) && (errno != ENOPROTOOPT)) { log_fatal("Can't set SO_REUSEPORT on dhcp socket for" " %s: %m", info->name); } } #endif /* Bind the socket to this interface's IP address. */ if (bind(sock, (struct sockaddr *)&name, name_len) < 0) { log_error("Can't bind to dhcp address: %m"); log_error("Please make sure there is no other dhcp server"); log_error("running and that there's no entry for dhcp or"); log_error("bootp in /etc/inetd.conf. Also make sure you"); log_error("are not running HP JetAdmin software, which"); log_fatal("includes a bootp server."); } #if defined(SO_BINDTODEVICE) /* Bind this socket to this interface. */ if ((local_family != AF_INET6) && (info->ifp != NULL) && setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, (char *)(info -> ifp), sizeof(*(info -> ifp))) < 0) { log_fatal("Can't set SO_BINDTODEVICE on dhcp socket for" " %s : %m", (char *)(info->ifp)); } #endif /* IP_BROADCAST_IF instructs the kernel which interface to send * IP packets whose destination address is 255.255.255.255. These * will be treated as subnet broadcasts on the interface identified * by ip address (info -> primary_address). This is only known to * be defined in SCO system headers, and may not be defined in all * releases. */ #if defined(SCO) && defined(IP_BROADCAST_IF) if (info->address_count && setsockopt(sock, IPPROTO_IP, IP_BROADCAST_IF, &info->addresses[0], sizeof(info->addresses[0])) < 0) log_fatal("Can't set IP_BROADCAST_IF on dhcp socket for" " %s: %m", info->name); #endif #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) /* * If we turn on IP_RECVPKTINFO we will be able to receive * the interface index information of the received packet. */ if (family == AF_INET) { int on = 1; if (setsockopt(sock, IPPROTO_IP, IP_RECVPKTINFO, &on, sizeof(on)) != 0) { log_fatal("Can't set IP_RECVPTKINFO on dhcp socket for" " %s: %m", info->name); } } #endif #ifdef DHCPv6 /* * If we turn on IPV6_PKTINFO, we will be able to receive * additional information, such as the destination IP address. * We need this to spot unicast packets. */ if (family == AF_INET6) { int on = 1; #ifdef IPV6_RECVPKTINFO /* RFC3542 */ if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on)) != 0) { log_fatal("setsockopt: IPV6_RECVPKTINFO for %s: %m", info->name); } #else /* RFC2292 */ if (setsockopt(sock, IPPROTO_IPV6, IPV6_PKTINFO, &on, sizeof(on)) != 0) { log_fatal("setsockopt: IPV6_PKTINFO for %s: %m", info->name); } #endif } #endif /* DHCPv6 */ return sock; } #ifdef DHCPv6 void set_multicast_hop_limit(struct interface_info* info, int hop_limit) { if (setsockopt(info->wfdesc, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hop_limit, sizeof(int)) < 0) { log_fatal("setsockopt: IPV6_MULTICAST_HOPS for %s: %m", info->name); } log_debug("Setting hop count limit to %d for interface %s", hop_limit, info->name); } #endif /* DHCPv6 */ #endif /* USE_SOCKET_SEND || USE_SOCKET_RECEIVE || USE_SOCKET_FALLBACK */ #if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK) void if_register_send (info) struct interface_info *info; { #ifndef USE_SOCKET_RECEIVE info->wfdesc = if_register_socket(info, AF_INET, 0, NULL); /* If this is a normal IPv4 address, get the hardware address. */ if (strcmp(info->name, "fallback") != 0) get_hw_addr(info->name, &info->hw_address); #if defined (USE_SOCKET_FALLBACK) /* Fallback only registers for send, but may need to receive as well. */ info->rfdesc = info->wfdesc; #endif #else info->wfdesc = info->rfdesc; #endif if (!quiet_interface_discovery) log_info ("Sending on Socket/%s%s%s", info->name, (info->shared_network ? "/" : ""), (info->shared_network ? info->shared_network->name : "")); } #if defined (USE_SOCKET_SEND) void if_deregister_send (info) struct interface_info *info; { #ifndef USE_SOCKET_RECEIVE close (info -> wfdesc); #endif info -> wfdesc = -1; if (!quiet_interface_discovery) log_info ("Disabling output on Socket/%s%s%s", info -> name, (info -> shared_network ? "/" : ""), (info -> shared_network ? info -> shared_network -> name : "")); } #endif /* USE_SOCKET_SEND */ #endif /* USE_SOCKET_SEND || USE_SOCKET_FALLBACK */ #ifdef USE_SOCKET_RECEIVE void if_register_receive (info) struct interface_info *info; { #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) if (global_v4_socket_references == 0) { global_v4_socket = if_register_socket(info, AF_INET, 0, NULL); if (global_v4_socket < 0) { /* * if_register_socket() fatally logs if it fails to * create a socket, this is just a sanity check. */ log_fatal("Failed to create AF_INET socket %s:%d", MDL); } } info->rfdesc = global_v4_socket; global_v4_socket_references++; #else /* If we're using the socket API for sending and receiving, we don't need to register this interface twice. */ info->rfdesc = if_register_socket(info, AF_INET, 0, NULL); #endif /* IP_PKTINFO... */ /* If this is a normal IPv4 address, get the hardware address. */ if (strcmp(info->name, "fallback") != 0) get_hw_addr(info->name, &info->hw_address); if (!quiet_interface_discovery) log_info ("Listening on Socket/%s%s%s", info->name, (info->shared_network ? "/" : ""), (info->shared_network ? info->shared_network->name : "")); } void if_deregister_receive (info) struct interface_info *info; { #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) /* Dereference the global v4 socket. */ if ((info->rfdesc == global_v4_socket) && (global_v4_socket_references > 0)) { global_v4_socket_references--; info->rfdesc = -1; } else { log_fatal("Impossible condition at %s:%d", MDL); } if (global_v4_socket_references == 0) { close(global_v4_socket); global_v4_socket = -1; } #else close(info->rfdesc); info->rfdesc = -1; #endif /* IP_PKTINFO... */ if (!quiet_interface_discovery) log_info ("Disabling input on Socket/%s%s%s", info -> name, (info -> shared_network ? "/" : ""), (info -> shared_network ? info -> shared_network -> name : "")); } #endif /* USE_SOCKET_RECEIVE */ #ifdef DHCPv6 /* * This function joins the interface to DHCPv6 multicast groups so we will * receive multicast messages. */ static void if_register_multicast(struct interface_info *info) { int sock = info->rfdesc; struct ipv6_mreq mreq; if (inet_pton(AF_INET6, All_DHCP_Relay_Agents_and_Servers, &mreq.ipv6mr_multiaddr) <= 0) { log_fatal("inet_pton: unable to convert '%s'", All_DHCP_Relay_Agents_and_Servers); } mreq.ipv6mr_interface = if_nametoindex(info->name); if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) < 0) { log_fatal("setsockopt: IPV6_JOIN_GROUP for %s: %m", info->name); } /* * The relay agent code sets the streams so you know which way * is up and down. But a relay agent shouldn't join to the * Server address, or else you get fun loops. So up or down * doesn't matter, we're just using that config to sense this is * a relay agent. */ if ((info->flags & INTERFACE_STREAMS) == 0) { if (inet_pton(AF_INET6, All_DHCP_Servers, &mreq.ipv6mr_multiaddr) <= 0) { log_fatal("inet_pton: unable to convert '%s'", All_DHCP_Servers); } mreq.ipv6mr_interface = if_nametoindex(info->name); if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) < 0) { log_fatal("setsockopt: IPV6_JOIN_GROUP for %s: %m", info->name); } } } void if_register6(struct interface_info *info, int do_multicast) { /* Bounce do_multicast to a stack variable because we may change it. */ int req_multi = do_multicast; if (no_global_v6_socket) { log_fatal("Impossible condition at %s:%d", MDL); } #if defined(RELAY_PORT) if (!relay_port || ((info->flags & INTERFACE_STREAMS) == INTERFACE_DOWNSTREAM)) { #endif if (global_v6_socket_references == 0) { global_v6_socket = if_register_socket(info, AF_INET6, &req_multi, NULL); if (global_v6_socket < 0) { /* * if_register_socket() fatally logs if it fails to * create a socket, this is just a sanity check. */ log_fatal("Impossible condition at %s:%d", MDL); } else if (bind_local_address6) { char addr6_str[INET6_ADDRSTRLEN]; if (inet_ntop(AF_INET6, &local_address6, addr6_str, sizeof(addr6_str)) == NULL) { log_fatal("inet_ntop: unable to convert " "local-address6"); } log_info("Bound to [%s]:%d", addr6_str, (int) ntohs(*libdhcp_callbacks.local_port)); } else { log_info("Bound to *:%d", (int) ntohs(*libdhcp_callbacks.local_port)); } } info->rfdesc = global_v6_socket; info->wfdesc = global_v6_socket; global_v6_socket_references++; #if defined(RELAY_PORT) } else { /* * If relay port is defined, we need to register one * IPv6 UPD socket to handle upstream server or relay agent * with a non-547 UDP local port. */ if ((relay_port_v6_socket_references == 0) && ((info->flags & INTERFACE_STREAMS) == INTERFACE_UPSTREAM)) { relay_port_v6_socket = if_register_socket(info, AF_INET6, &req_multi, NULL); if (relay_port_v6_socket < 0) { log_fatal("Impossible condition at %s:%d", MDL); } else { log_info("Bound to relay port *:%d", (int) ntohs(relay_port)); } } info->rfdesc = relay_port_v6_socket; info->wfdesc = relay_port_v6_socket; relay_port_v6_socket_references++; } #endif if (req_multi) if_register_multicast(info); get_hw_addr(info->name, &info->hw_address); if (!quiet_interface_discovery) { if (info->shared_network != NULL) { log_info("Listening on Socket/%d/%s/%s", global_v6_socket, info->name, info->shared_network->name); log_info("Sending on Socket/%d/%s/%s", global_v6_socket, info->name, info->shared_network->name); } else { log_info("Listening on Socket/%s", info->name); log_info("Sending on Socket/%s", info->name); } } } /* * Register an IPv6 socket bound to the link-local address of * the argument interface (used by clients on a multiple interface box, * vs. a server or a relay using the global IPv6 socket and running * *only* in a single instance). */ void if_register_linklocal6(struct interface_info *info) { int sock; int count; struct in6_addr *addr6 = NULL; int req_multi = 0; if (global_v6_socket >= 0) { log_fatal("Impossible condition at %s:%d", MDL); } no_global_v6_socket = 1; /* get the (?) link-local address */ for (count = 0; count < info->v6address_count; count++) { addr6 = &info->v6addresses[count]; if (IN6_IS_ADDR_LINKLOCAL(addr6)) break; } if (!addr6) { log_fatal("no link-local IPv6 address for %s", info->name); } sock = if_register_socket(info, AF_INET6, &req_multi, addr6); if (sock < 0) { log_fatal("if_register_socket for %s fails", info->name); } info->rfdesc = sock; info->wfdesc = sock; get_hw_addr(info->name, &info->hw_address); if (!quiet_interface_discovery) { if (info->shared_network != NULL) { log_info("Listening on Socket/%d/%s/%s", global_v6_socket, info->name, info->shared_network->name); log_info("Sending on Socket/%d/%s/%s", global_v6_socket, info->name, info->shared_network->name); } else { log_info("Listening on Socket/%s", info->name); log_info("Sending on Socket/%s", info->name); } } } void if_deregister6(struct interface_info *info) { /* client case */ if (no_global_v6_socket) { close(info->rfdesc); info->rfdesc = -1; info->wfdesc = -1; } else if ((info->rfdesc == global_v6_socket) && (info->wfdesc == global_v6_socket) && (global_v6_socket_references > 0)) { /* Dereference the global v6 socket. */ global_v6_socket_references--; info->rfdesc = -1; info->wfdesc = -1; #if defined(RELAY_PORT) } else if (relay_port && (info->rfdesc == relay_port_v6_socket) && (info->wfdesc == relay_port_v6_socket) && (relay_port_v6_socket_references > 0)) { /* Dereference the relay port v6 socket. */ relay_port_v6_socket_references--; info->rfdesc = -1; info->wfdesc = -1; #endif } else { log_fatal("Impossible condition at %s:%d", MDL); } if (!quiet_interface_discovery) { if (info->shared_network != NULL) { log_info("Disabling input on Socket/%s/%s", info->name, info->shared_network->name); log_info("Disabling output on Socket/%s/%s", info->name, info->shared_network->name); } else { log_info("Disabling input on Socket/%s", info->name); log_info("Disabling output on Socket/%s", info->name); } } if (!no_global_v6_socket) { if (global_v6_socket_references == 0) { close(global_v6_socket); global_v6_socket = -1; log_info("Unbound from *:%d", (int) ntohs(*libdhcp_callbacks.local_port)); } #if defined(RELAY_PORT) if (relay_port && (relay_port_v6_socket_references == 0)) { close(relay_port_v6_socket); relay_port_v6_socket = -1; log_info("Unbound from relay port *:%d", (int) ntohs(relay_port)); } #endif } } #endif /* DHCPv6 */ #if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK) ssize_t send_packet (interface, packet, raw, len, from, to, hto) struct interface_info *interface; struct packet *packet; struct dhcp_packet *raw; size_t len; struct in_addr from; struct sockaddr_in *to; struct hardware *hto; { int result; #ifdef IGNORE_HOSTUNREACH int retry = 0; do { #endif #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) struct in_pktinfo pktinfo; if (interface->ifp != NULL) { memset(&pktinfo, 0, sizeof (pktinfo)); pktinfo.ipi_ifindex = interface->ifp->ifr_index; if (setsockopt(interface->wfdesc, IPPROTO_IP, IP_PKTINFO, (char *)&pktinfo, sizeof(pktinfo)) < 0) log_fatal("setsockopt: IP_PKTINFO for %s: %m", (char*)(interface->ifp)); } #endif result = sendto (interface -> wfdesc, (char *)raw, len, 0, (struct sockaddr *)to, sizeof *to); #ifdef IGNORE_HOSTUNREACH } while (to -> sin_addr.s_addr == htonl (INADDR_BROADCAST) && result < 0 && (errno == EHOSTUNREACH || errno == ECONNREFUSED) && retry++ < 10); #endif if (result < 0) { log_error ("send_packet: %m"); if (errno == ENETUNREACH) log_error ("send_packet: please consult README file%s", " regarding broadcast address."); } return result; } #endif /* USE_SOCKET_SEND || USE_SOCKET_FALLBACK */ #ifdef DHCPv6 /* * Solaris 9 is missing the CMSG_LEN and CMSG_SPACE macros, so we will * synthesize them (based on the BIND 9 technique). */ #ifndef CMSG_LEN static size_t CMSG_LEN(size_t len) { size_t hdrlen; /* * Cast NULL so that any pointer arithmetic performed by CMSG_DATA * is correct. */ hdrlen = (size_t)CMSG_DATA(((struct cmsghdr *)NULL)); return hdrlen + len; } #endif /* !CMSG_LEN */ #ifndef CMSG_SPACE static size_t CMSG_SPACE(size_t len) { struct msghdr msg; struct cmsghdr *cmsgp; /* * XXX: The buffer length is an ad-hoc value, but should be enough * in a practical sense. */ union { struct cmsghdr cmsg_sizer; u_int8_t pktinfo_sizer[sizeof(struct cmsghdr) + 1024]; } dummybuf; memset(&msg, 0, sizeof(msg)); msg.msg_control = &dummybuf; msg.msg_controllen = sizeof(dummybuf); cmsgp = (struct cmsghdr *)&dummybuf; cmsgp->cmsg_len = CMSG_LEN(len); cmsgp = CMSG_NXTHDR(&msg, cmsgp); if (cmsgp != NULL) { return (char *)cmsgp - (char *)msg.msg_control; } else { return 0; } } #endif /* !CMSG_SPACE */ #endif /* DHCPv6 */ #if defined(DHCPv6) || \ (defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && \ defined(USE_V4_PKTINFO)) /* * For both send_packet6() and receive_packet6() we need to allocate * space for the cmsg header information. We do this once and reuse * the buffer. We also need the control buf for send_packet() and * receive_packet() when we use a single socket and IP_PKTINFO to * send the packet out the correct interface. */ static void *control_buf = NULL; static size_t control_buf_len = 0; static void allocate_cmsg_cbuf(void) { control_buf_len = CMSG_SPACE(sizeof(struct in6_pktinfo)); control_buf = dmalloc(control_buf_len, MDL); return; } #endif /* DHCPv6, IP_PKTINFO ... */ #ifdef DHCPv6 /* * For both send_packet6() and receive_packet6() we need to use the * sendmsg()/recvmsg() functions rather than the simpler send()/recv() * functions. * * In the case of send_packet6(), we need to do this in order to insure * that the reply packet leaves on the same interface that it arrived * on. * * In the case of receive_packet6(), we need to do this in order to * get the IP address the packet was sent to. This is used to identify * whether a packet is multicast or unicast. * * Helpful man pages: recvmsg, readv (talks about the iovec stuff), cmsg. * * Also see the sections in RFC 3542 about IPV6_PKTINFO. */ /* Send an IPv6 packet */ ssize_t send_packet6(struct interface_info *interface, const unsigned char *raw, size_t len, struct sockaddr_in6 *to) { struct msghdr m; struct iovec v; struct sockaddr_in6 dst; int result; struct in6_pktinfo *pktinfo; struct cmsghdr *cmsg; unsigned int ifindex; /* * If necessary allocate space for the control message header. * The space is common between send and receive. */ if (control_buf == NULL) { allocate_cmsg_cbuf(); if (control_buf == NULL) { log_error("send_packet6: unable to allocate cmsg header"); return(ENOMEM); } } memset(control_buf, 0, control_buf_len); /* * Initialize our message header structure. */ memset(&m, 0, sizeof(m)); /* * Set the target address we're sending to. * Enforce the scope ID for bogus BSDs. */ memcpy(&dst, to, sizeof(dst)); m.msg_name = &dst; m.msg_namelen = sizeof(dst); ifindex = if_nametoindex(interface->name); // Per OpenBSD patch-common_socket_c,v 1.7 2018/03/06 08:37:39 sthen Exp // always set the scope id. We'll leave the test for no global socket // in place for all others. #ifndef __OpenBSD__ if (no_global_v6_socket) #endif dst.sin6_scope_id = ifindex; /* * Set the data buffer we're sending. (Using this wacky * "scatter-gather" stuff... we only have a single chunk * of data to send, so we declare a single vector entry.) */ v.iov_base = (char *)raw; v.iov_len = len; m.msg_iov = &v; m.msg_iovlen = 1; /* * Setting the interface is a bit more involved. * * We have to create a "control message", and set that to * define the IPv6 packet information. We could set the * source address if we wanted, but we can safely let the * kernel decide what that should be. */ m.msg_control = control_buf; m.msg_controllen = control_buf_len; cmsg = CMSG_FIRSTHDR(&m); INSIST(cmsg != NULL); cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; cmsg->cmsg_len = CMSG_LEN(sizeof(*pktinfo)); pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg); memset(pktinfo, 0, sizeof(*pktinfo)); pktinfo->ipi6_addr = local_address6; pktinfo->ipi6_ifindex = ifindex; result = sendmsg(interface->wfdesc, &m, 0); if (result < 0) { log_error("send_packet6: %m"); } return result; } #endif /* DHCPv6 */ #ifdef USE_SOCKET_RECEIVE ssize_t receive_packet (interface, buf, len, from, hfrom) struct interface_info *interface; unsigned char *buf; size_t len; struct sockaddr_in *from; struct hardware *hfrom; { #if !(defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO)) SOCKLEN_T flen = sizeof *from; #endif int result; /* * The normal Berkeley socket interface doesn't give us any way * to know what hardware interface we received the message on, * but we should at least make sure the structure is emptied. */ memset(hfrom, 0, sizeof(*hfrom)); #ifdef IGNORE_HOSTUNREACH int retry = 0; do { #endif #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO) struct msghdr m; struct iovec v; struct cmsghdr *cmsg; struct in_pktinfo *pktinfo; unsigned int ifindex; /* * If necessary allocate space for the control message header. * The space is common between send and receive. */ if (control_buf == NULL) { allocate_cmsg_cbuf(); if (control_buf == NULL) { log_error("receive_packet: unable to allocate cmsg " "header"); return(ENOMEM); } } memset(control_buf, 0, control_buf_len); /* * Initialize our message header structure. */ memset(&m, 0, sizeof(m)); /* * Point so we can get the from address. */ m.msg_name = from; m.msg_namelen = sizeof(*from); /* * Set the data buffer we're receiving. (Using this wacky * "scatter-gather" stuff... but we that doesn't really make * sense for us, so we use a single vector entry.) */ v.iov_base = buf; v.iov_len = len; m.msg_iov = &v; m.msg_iovlen = 1; /* * Getting the interface is a bit more involved. * * We set up some space for a "control message". We have * previously asked the kernel to give us packet * information (when we initialized the interface), so we * should get the interface index from that. */ m.msg_control = control_buf; m.msg_controllen = control_buf_len; result = recvmsg(interface->rfdesc, &m, 0); if (result >= 0) { /* * If we did read successfully, then we need to loop * through the control messages we received and * find the one with our inteface index. */ cmsg = CMSG_FIRSTHDR(&m); while (cmsg != NULL) { if ((cmsg->cmsg_level == IPPROTO_IP) && (cmsg->cmsg_type == IP_PKTINFO)) { pktinfo = (struct in_pktinfo *)CMSG_DATA(cmsg); ifindex = pktinfo->ipi_ifindex; /* * We pass the ifindex back to the caller * using the unused hfrom parameter avoiding * interface changes between sockets and * the discover code. */ memcpy(hfrom->hbuf, &ifindex, sizeof(ifindex)); return (result); } cmsg = CMSG_NXTHDR(&m, cmsg); } /* * We didn't find the necessary control message * flag it as an error */ result = -1; errno = EIO; } #else result = recvfrom(interface -> rfdesc, (char *)buf, len, 0, (struct sockaddr *)from, &flen); #endif /* IP_PKTINFO ... */ #ifdef IGNORE_HOSTUNREACH } while (result < 0 && (errno == EHOSTUNREACH || errno == ECONNREFUSED) && retry++ < 10); #endif return (result); } #endif /* USE_SOCKET_RECEIVE */ #ifdef DHCPv6 ssize_t receive_packet6(struct interface_info *interface, unsigned char *buf, size_t len, struct sockaddr_in6 *from, struct in6_addr *to_addr, unsigned int *if_idx) { struct msghdr m; struct iovec v; int result; struct cmsghdr *cmsg; struct in6_pktinfo *pktinfo; /* * If necessary allocate space for the control message header. * The space is common between send and receive. */ if (control_buf == NULL) { allocate_cmsg_cbuf(); if (control_buf == NULL) { log_error("receive_packet6: unable to allocate cmsg " "header"); return(ENOMEM); } } memset(control_buf, 0, control_buf_len); /* * Initialize our message header structure. */ memset(&m, 0, sizeof(m)); /* * Point so we can get the from address. */ m.msg_name = from; m.msg_namelen = sizeof(*from); /* * Set the data buffer we're receiving. (Using this wacky * "scatter-gather" stuff... but we that doesn't really make * sense for us, so we use a single vector entry.) */ v.iov_base = buf; v.iov_len = len; m.msg_iov = &v; m.msg_iovlen = 1; /* * Getting the interface is a bit more involved. * * We set up some space for a "control message". We have * previously asked the kernel to give us packet * information (when we initialized the interface), so we * should get the destination address from that. */ m.msg_control = control_buf; m.msg_controllen = control_buf_len; result = recvmsg(interface->rfdesc, &m, 0); if (result >= 0) { /* * If we did read successfully, then we need to loop * through the control messages we received and * find the one with our destination address. */ cmsg = CMSG_FIRSTHDR(&m); while (cmsg != NULL) { if ((cmsg->cmsg_level == IPPROTO_IPV6) && (cmsg->cmsg_type == IPV6_PKTINFO)) { pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg); *to_addr = pktinfo->ipi6_addr; *if_idx = pktinfo->ipi6_ifindex; return (result); } cmsg = CMSG_NXTHDR(&m, cmsg); } /* * We didn't find the necessary control message * flag is as an error */ result = -1; errno = EIO; } return (result); } #endif /* DHCPv6 */ #if defined (USE_SOCKET_FALLBACK) /* This just reads in a packet and silently discards it. */ isc_result_t fallback_discard (object) omapi_object_t *object; { char buf [1540]; struct sockaddr_in from; SOCKLEN_T flen = sizeof from; int status; struct interface_info *interface; if (object -> type != dhcp_type_interface) return DHCP_R_INVALIDARG; interface = (struct interface_info *)object; status = recvfrom (interface -> wfdesc, buf, sizeof buf, 0, (struct sockaddr *)&from, &flen); #if defined (DEBUG) /* Only report fallback discard errors if we're debugging. */ if (status < 0) { log_error ("fallback_discard: %m"); return ISC_R_UNEXPECTED; } #else /* ignore the fact that status value is never used */ IGNORE_UNUSED(status); #endif return ISC_R_SUCCESS; } #endif /* USE_SOCKET_FALLBACK */ #if defined (USE_SOCKET_SEND) int can_unicast_without_arp (ip) struct interface_info *ip; { return 0; } int can_receive_unicast_unconfigured (ip) struct interface_info *ip; { #if defined (SOCKET_CAN_RECEIVE_UNICAST_UNCONFIGURED) return 1; #else return 0; #endif } int supports_multiple_interfaces (ip) struct interface_info *ip; { #if defined(SO_BINDTODEVICE) || \ (defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && \ defined(USE_V4_PKTINFO)) return(1); #else return(0); #endif } /* If we have SO_BINDTODEVICE, set up a fallback interface; otherwise, do not. */ void maybe_setup_fallback () { #if defined (USE_SOCKET_FALLBACK) isc_result_t status; struct interface_info *fbi = (struct interface_info *)0; if (setup_fallback (&fbi, MDL)) { fbi -> wfdesc = if_register_socket (fbi, AF_INET, 0, NULL); fbi -> rfdesc = fbi -> wfdesc; log_info ("Sending on Socket/%s%s%s", fbi -> name, (fbi -> shared_network ? "/" : ""), (fbi -> shared_network ? fbi -> shared_network -> name : "")); status = omapi_register_io_object ((omapi_object_t *)fbi, if_readsocket, 0, fallback_discard, 0, 0); if (status != ISC_R_SUCCESS) log_fatal ("Can't register I/O handle for %s: %s", fbi -> name, isc_result_totext (status)); interface_dereference (&fbi, MDL); } #endif } #if defined(sun) && defined(USE_V4_PKTINFO) /* This code assumes the existence of SIOCGLIFHWADDR */ void get_hw_addr(const char *name, struct hardware *hw) { struct sockaddr_dl *dladdrp; int sock, i; struct lifreq lifr; memset(&lifr, 0, sizeof (lifr)); (void) strlcpy(lifr.lifr_name, name, sizeof (lifr.lifr_name)); /* * Check if the interface is a virtual or IPMP interface - in those * cases it has no hw address, so generate a random one. */ if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0 || ioctl(sock, SIOCGLIFFLAGS, &lifr) < 0) { if (sock != -1) (void) close(sock); #ifdef DHCPv6 /* * If approrpriate try this with an IPv6 socket */ if ((sock = socket(AF_INET6, SOCK_DGRAM, 0)) >= 0 && ioctl(sock, SIOCGLIFFLAGS, &lifr) >= 0) { goto flag_check; } if (sock != -1) (void) close(sock); #endif log_fatal("Couldn't get interface flags for %s: %m", name); } flag_check: if (lifr.lifr_flags & (IFF_VIRTUAL|IFF_IPMP)) { hw->hlen = sizeof (hw->hbuf); srandom((long)gethrtime()); hw->hbuf[0] = HTYPE_IPMP; for (i = 1; i < hw->hlen; ++i) { hw->hbuf[i] = random() % 256; } if (sock != -1) (void) close(sock); return; } if (ioctl(sock, SIOCGLIFHWADDR, &lifr) < 0) log_fatal("Couldn't get interface hardware address for %s: %m", name); dladdrp = (struct sockaddr_dl *)&lifr.lifr_addr; hw->hlen = dladdrp->sdl_alen+1; switch (dladdrp->sdl_type) { case DL_CSMACD: /* IEEE 802.3 */ case DL_ETHER: hw->hbuf[0] = HTYPE_ETHER; break; case DL_TPR: hw->hbuf[0] = HTYPE_IEEE802; break; case DL_FDDI: hw->hbuf[0] = HTYPE_FDDI; break; case DL_IB: hw->hbuf[0] = HTYPE_INFINIBAND; break; default: log_fatal("%s: unsupported DLPI MAC type %lu", name, (unsigned long)dladdrp->sdl_type); } memcpy(hw->hbuf+1, LLADDR(dladdrp), hw->hlen-1); if (sock != -1) (void) close(sock); } #endif /* defined(sun) */ #endif /* USE_SOCKET_SEND */