/** * Copyright (C) 2012-2013 Steven Barth * Copyright (C) 2018 Hans Dedecker * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License v2 as published by * the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ #include #include #include #include #include #include #include #include #include #include #include #include "router.h" #include "odhcpd.h" static void forward_router_solicitation(const struct interface *iface); static void forward_router_advertisement(uint8_t *data, size_t len); static void handle_icmpv6(void *addr, void *data, size_t len, struct interface *iface, void *dest); static void trigger_router_advert(struct uloop_timeout *event); static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info); static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, }; static struct netevent_handler router_netevent_handler = { .cb = router_netevent_cb, }; static FILE *fp_route = NULL; #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX) int router_init(void) { struct icmp6_filter filt; int ret = 0; /* Open ICMPv6 socket */ router_event.uloop.fd = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6); if (router_event.uloop.fd < 0) { syslog(LOG_ERR, "socket(AF_INET6): %m"); ret = -1; goto out; } /* Let the kernel compute our checksums */ int val = 2; if (setsockopt(router_event.uloop.fd, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_CHECKSUM): %m"); ret = -1; goto out; } /* This is required by RFC 4861 */ val = 255; if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m"); ret = -1; goto out; } if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_UNICAST_HOPS): %m"); ret = -1; goto out; } /* We need to know the source interface */ val = 1; if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m"); ret = -1; goto out; } if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_RECVHOPLIMIT): %m"); ret = -1; goto out; } /* Don't loop back */ val = 0; if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val)) < 0) { syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m"); ret = -1; goto out; } /* Filter ICMPv6 package types */ ICMP6_FILTER_SETBLOCKALL(&filt); ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt); ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt); if (setsockopt(router_event.uloop.fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt)) < 0) { syslog(LOG_ERR, "setsockopt(ICMP6_FILTER): %m"); ret = -1; goto out; } if (!(fp_route = fopen("/proc/net/ipv6_route", "r"))) { syslog(LOG_ERR, "fopen(/proc/net/ipv6_route): %m"); ret = -1; goto out; } if (netlink_add_netevent_handler(&router_netevent_handler) < 0) { syslog(LOG_ERR, "Failed to add netevent handler"); ret = -1; goto out; } /* Register socket */ odhcpd_register(&router_event); out: if (ret < 0) { if (router_event.uloop.fd > 0) { close(router_event.uloop.fd); router_event.uloop.fd = -1; } if (fp_route) { fclose(fp_route); fp_route = NULL; } } return ret; } int router_setup_interface(struct interface *iface, bool enable) { struct ipv6_mreq mreq; int ret = 0; if (!fp_route || router_event.uloop.fd < 0) { ret = -1; goto out; } uloop_timeout_cancel(&iface->timer_rs); iface->timer_rs.cb = NULL; memset(&mreq, 0, sizeof(mreq)); mreq.ipv6mr_interface = iface->ifindex; inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr); setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &mreq.ipv6mr_multiaddr); setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); if (!enable) { if (iface->ra == MODE_SERVER || (iface->ra == MODE_RELAY && !iface->master)) trigger_router_advert(&iface->timer_rs); } else { if (iface->ra == MODE_RELAY && iface->master) { inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr); forward_router_solicitation(iface); } else if (iface->ra == MODE_SERVER && !iface->master) { iface->timer_rs.cb = trigger_router_advert; uloop_timeout_set(&iface->timer_rs, 1000); } if (iface->ra == MODE_RELAY || (iface->ra == MODE_SERVER && !iface->master)) { if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) { ret = -1; syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m"); } } } out: return ret; } static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info) { struct interface *iface; switch (event) { case NETEV_ROUTE6_ADD: case NETEV_ROUTE6_DEL: if (info->rt.dst_len) break; list_for_each_entry(iface, &interfaces, head) { if (iface->ra == MODE_SERVER && !iface->master) uloop_timeout_set(&iface->timer_rs, 1000); } break; case NETEV_ADDR6LIST_CHANGE: iface = info->iface; if (iface && iface->ra == MODE_SERVER && !iface->master) uloop_timeout_set(&iface->timer_rs, 1000); break; default: break; } } static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len) { struct icmp6_hdr *hdr = (struct icmp6_hdr *)data; struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len]; /* Hoplimit is already checked in odhcpd_receive_packets */ if (len < sizeof(*hdr) || hdr->icmp6_code) return false; switch (hdr->icmp6_type) { case ND_ROUTER_ADVERT: if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr)) return false; opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1); break; case ND_ROUTER_SOLICIT: opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1); break; default: return false; } icmpv6_for_each_option(opt, opt, end) if (opt->type == ND_OPT_SOURCE_LINKADDR && IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) && hdr->icmp6_type == ND_ROUTER_SOLICIT) return false; /* Check all options parsed successfully */ return opt == end; } /* Detect whether a default route exists, also find the source prefixes */ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len) { rewind(fp_route); char line[512], ifname[16]; bool found_default = false; struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0, .dprefix = 0, .preferred = 0, .valid = 0}; while (fgets(line, sizeof(line), fp_route)) { uint32_t rflags; if (sscanf(line, "00000000000000000000000000000000 00 " "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) && strcmp(ifname, "lo")) { found_default = true; } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s " "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo", &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) && p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) { // Find source prefixes by scanning through unreachable-routes p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]); p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]); for (ssize_t i = 0; i < len; ++i) { if (n[i].prefix <= 64 && n[i].prefix >= p.prefix && !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) { n[i].dprefix = p.prefix; break; } } } } return found_default; } static int calc_adv_interval(struct interface *iface, uint32_t minvalid, uint32_t *maxival) { uint32_t minival = iface->ra_mininterval; int msecs; *maxival = iface->ra_maxinterval; if (*maxival > minvalid/3) *maxival = minvalid/3; if (*maxival > MaxRtrAdvInterval) *maxival = MaxRtrAdvInterval; else if (*maxival < 4) *maxival = 4; if (minival < MinRtrAdvInterval) minival = MinRtrAdvInterval; else if (minival > (*maxival * 3)/4) minival = (*maxival >= 9 ? *maxival/3 : *maxival); odhcpd_urandom(&msecs, sizeof(msecs)); msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) + minival*1000; return msecs; } static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival) { uint16_t lifetime = 3*maxival; if (iface->ra_lifetime >= 0) { lifetime = iface->ra_lifetime; if (lifetime < maxival) lifetime = maxival; else if (lifetime > 9000) lifetime = 9000; } return lifetime; } enum { IOV_RA_ADV=0, IOV_RA_PFXS, IOV_RA_ROUTES, IOV_RA_DNS, IOV_RA_DNS_ADDR, IOV_RA_SEARCH, IOV_RA_ADV_INTERVAL, IOV_RA_TOTAL, }; /* Router Advert server mode */ static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from) { time_t now = odhcpd_time(); int mtu = iface->ra_mtu; int hlim = iface->ra_hoplimit; char buf[INET6_ADDRSTRLEN]; if (mtu == 0) mtu = odhcpd_get_interface_config(iface->ifname, "mtu"); if (mtu < 1280) mtu = 1280; if (hlim == 0) hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit"); struct { struct nd_router_advert h; struct icmpv6_opt lladdr; struct nd_opt_mtu mtu; } adv = { .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0}, .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}}, .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)}, }; if (hlim > 0) adv.h.nd_ra_curhoplimit = hlim; if (iface->dhcpv6) { adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER; if (iface->ra_managed >= RA_MANAGED_MFLAG) adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED; } if (iface->route_preference < 0) adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW; else if (iface->route_preference > 0) adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH; adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime); adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime); odhcpd_get_mac(iface, adv.lladdr.data); /* If not currently shutting down */ struct odhcpd_ipaddr *addrs = NULL; ssize_t ipcnt = 0; uint32_t minvalid = UINT32_MAX; bool default_route = false; bool valid_prefix = false; /* If not shutdown */ if (iface->timer_rs.cb) { size_t size = sizeof(*addrs) * iface->addr6_len; addrs = alloca(size); memcpy(addrs, iface->addr6, size); ipcnt = iface->addr6_len; /* Check default route */ if (iface->default_router) { default_route = true; if (iface->default_router > 1) valid_prefix = true; } else if (parse_routes(addrs, ipcnt)) default_route = true; } /* DNS Recursive DNS */ struct in6_addr dns_pref, *dns_addr = NULL; size_t dns_cnt = 0; if (iface->ra_dns) { if (iface->dns_cnt > 0) { dns_addr = iface->dns; dns_cnt = iface->dns_cnt; } else if (!odhcpd_get_interface_dns_addr(iface, &dns_pref)) { dns_addr = &dns_pref; dns_cnt = 1; } } /* Construct Prefix Information options */ size_t pfxs_cnt = 0; struct nd_opt_prefix_info *pfxs = NULL; for (ssize_t i = 0; i < ipcnt; ++i) { struct odhcpd_ipaddr *addr = &addrs[i]; uint32_t preferred = 0; uint32_t valid = 0; if (addr->prefix > 96 || addr->valid <= (uint32_t)now) { syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s", inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)), addr->prefix, addr->valid, iface->ifname); continue; } if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr, iface->pio_filter_length) != 0 || addr->prefix < iface->pio_filter_length) continue; // PIO filtered out of this RA struct nd_opt_prefix_info *p = NULL; for (size_t i = 0; i < pfxs_cnt; ++i) { if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len && !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix, &addr->addr.in6, addr->prefix)) p = &pfxs[i]; } if (!p) { struct nd_opt_prefix_info *tmp; tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1)); if (!tmp) { syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname); continue; } pfxs = tmp; p = &pfxs[pfxs_cnt++]; memset(p, 0, sizeof(*p)); } if (addr->preferred > (uint32_t)now) { preferred = TIME_LEFT(addr->preferred, now); if (iface->ra_useleasetime && preferred > iface->dhcpv4_leasetime) preferred = iface->dhcpv4_leasetime; } valid = TIME_LEFT(addr->valid, now); if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime) valid = iface->dhcpv4_leasetime; if (minvalid > valid) minvalid = valid; if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router) valid_prefix = true; odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr.in6, (iface->ra_advrouter) ? 128 : addr->prefix); p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION; p->nd_opt_pi_len = 4; p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix; p->nd_opt_pi_flags_reserved = 0; if (!iface->ra_not_onlink) p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK; if (iface->ra_managed < RA_MANAGED_NO_AFLAG && addr->prefix <= 64) p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO; if (iface->ra_advrouter) p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR; p->nd_opt_pi_preferred_time = htonl(preferred); p->nd_opt_pi_valid_time = htonl(valid); } /* Calculate periodic transmit */ uint32_t maxival; int msecs = calc_adv_interval(iface, minvalid, &maxival); if (default_route) { if (!valid_prefix) { syslog(LOG_WARNING, "A default route is present but there is no public prefix " "on %s thus we don't announce a default route!", iface->ifname); adv.h.nd_ra_router_lifetime = 0; } else adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival)); } else adv.h.nd_ra_router_lifetime = 0; syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname); struct { uint8_t type; uint8_t len; uint8_t pad; uint8_t pad2; uint32_t lifetime; } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0}; /* DNS Search options */ uint8_t *search_domain = NULL; size_t search_len = 0, search_padded = 0; if (iface->ra_dns) { search_len = iface->search_len; search_domain = iface->search; if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) { uint8_t search_buf[256]; int len = dn_comp(_res.dnsrch[0], search_buf, sizeof(search_buf), NULL, NULL); if (len > 0) { search_domain = search_buf; search_len = len; } } } if (search_len > 0) search_padded = ((search_len + 7) & (~7)) + 8; struct { uint8_t type; uint8_t len; uint8_t pad; uint8_t pad2; uint32_t lifetime; uint8_t name[]; } *search = alloca(sizeof(*search) + search_padded); search->type = ND_OPT_DNS_SEARCH; search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0; search->pad = 0; search->pad2 = 0; if (search_len > 0) { memcpy(search->name, search_domain, search_len); memset(&search->name[search_len], 0, search_padded - search_len); } size_t routes_cnt = 0; struct { uint8_t type; uint8_t len; uint8_t prefix; uint8_t flags; uint32_t lifetime; uint32_t addr[4]; } *tmp, *routes = NULL; for (ssize_t i = 0; i < ipcnt; ++i) { struct odhcpd_ipaddr *addr = &addrs[i]; if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now) { syslog(LOG_INFO, "Address %s (dprefix %d, valid %u) not suitable as RA route on %s", inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)), addr->dprefix, addr->valid, iface->ifname); continue; /* Address not suitable */ } if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr, iface->pio_filter_length) != 0 || addr->prefix < iface->pio_filter_length) continue; /* RIO filtered out of this RA */ if (addr->dprefix > 32) { addr->addr.in6.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1)); } else if (addr->dprefix <= 32) { addr->addr.in6.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1)); addr->addr.in6.s6_addr32[1] = 0; } tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1)); if (!tmp) { syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname); continue; } routes = tmp; memset(&routes[routes_cnt], 0, sizeof(*routes)); routes[routes_cnt].type = ND_OPT_ROUTE_INFO; routes[routes_cnt].len = sizeof(*routes) / 8; routes[routes_cnt].prefix = addr->dprefix; routes[routes_cnt].flags = 0; if (iface->route_preference < 0) routes[routes_cnt].flags |= ND_RA_PREF_LOW; else if (iface->route_preference > 0) routes[routes_cnt].flags |= ND_RA_PREF_HIGH; routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now)); routes[routes_cnt].addr[0] = addr->addr.in6.s6_addr32[0]; routes[routes_cnt].addr[1] = addr->addr.in6.s6_addr32[1]; routes[routes_cnt].addr[2] = 0; routes[routes_cnt].addr[3] = 0; ++routes_cnt; } search->lifetime = htonl(maxival*10); dns.lifetime = search->lifetime; struct icmpv6_opt adv_interval = { .type = ND_OPT_RTR_ADV_INTERVAL, .len = 1, .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000} }; struct iovec iov[IOV_RA_TOTAL] = { [IOV_RA_ADV] = {&adv, sizeof(adv)}, [IOV_RA_PFXS] = {pfxs, pfxs_cnt * sizeof(*pfxs)}, [IOV_RA_ROUTES] = {routes, routes_cnt * sizeof(*routes)}, [IOV_RA_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0}, [IOV_RA_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)}, [IOV_RA_SEARCH] = {search, search->len * 8}, [IOV_RA_ADV_INTERVAL] = {&adv_interval, adv_interval.len * 8}}; struct sockaddr_in6 dest; memset(&dest, 0, sizeof(dest)); dest.sin6_family = AF_INET6; if (from && !IN6_IS_ADDR_UNSPECIFIED(from)) dest.sin6_addr = *from; else inet_pton(AF_INET6, ALL_IPV6_NODES, &dest.sin6_addr); odhcpd_send(router_event.uloop.fd, &dest, iov, ARRAY_SIZE(iov), iface); free(pfxs); free(routes); return msecs; } static void trigger_router_advert(struct uloop_timeout *event) { struct interface *iface = container_of(event, struct interface, timer_rs); int msecs = send_router_advert(iface, NULL); /* Rearm timer if not shut down */ if (event->cb) uloop_timeout_set(event, msecs); } /* Event handler for incoming ICMPv6 packets */ static void handle_icmpv6(void *addr, void *data, size_t len, struct interface *iface, _unused void *dest) { struct icmp6_hdr *hdr = data; struct sockaddr_in6 *from = addr; if (!router_icmpv6_valid(addr, data, len)) return; if ((iface->ra == MODE_SERVER && !iface->master)) { /* Server mode */ if (hdr->icmp6_type == ND_ROUTER_SOLICIT) send_router_advert(iface, &from->sin6_addr); } else if (iface->ra == MODE_RELAY) { /* Relay mode */ if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master) forward_router_advertisement(data, len); else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master) forward_router_solicitation(odhcpd_get_master_interface()); } } /* Forward router solicitation */ static void forward_router_solicitation(const struct interface *iface) { struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}}; struct iovec iov = {&rs, sizeof(rs)}; struct sockaddr_in6 all_routers; if (!iface) return; memset(&all_routers, 0, sizeof(all_routers)); all_routers.sin6_family = AF_INET6; inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &all_routers.sin6_addr); all_routers.sin6_scope_id = iface->ifindex; syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname); odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface); } /* Handler for incoming router solicitations on slave interfaces */ static void forward_router_advertisement(uint8_t *data, size_t len) { struct nd_router_advert *adv = (struct nd_router_advert *)data; struct sockaddr_in6 all_nodes; /* Rewrite options */ uint8_t *end = data + len; uint8_t *mac_ptr = NULL; struct in6_addr *dns_ptr = NULL; size_t dns_count = 0; struct icmpv6_opt *opt; icmpv6_for_each_option(opt, &adv[1], end) { if (opt->type == ND_OPT_SOURCE_LINKADDR) { /* Store address of source MAC-address */ mac_ptr = opt->data; } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) { /* Check if we have to rewrite DNS */ dns_ptr = (struct in6_addr*)&opt->data[6]; dns_count = (opt->len - 1) / 2; } } syslog(LOG_NOTICE, "Got a RA"); /* Indicate a proxy, however we don't follow the rest of RFC 4389 yet */ adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY; /* Forward advertisement to all slave interfaces */ memset(&all_nodes, 0, sizeof(all_nodes)); all_nodes.sin6_family = AF_INET6; inet_pton(AF_INET6, ALL_IPV6_NODES, &all_nodes.sin6_addr); struct iovec iov = {data, len}; struct interface *iface; list_for_each_entry(iface, &interfaces, head) { if (iface->ra != MODE_RELAY || iface->master) continue; /* Fixup source hardware address option */ if (mac_ptr) odhcpd_get_mac(iface, mac_ptr); /* If we have to rewrite DNS entries */ if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) { const struct in6_addr *rewrite = iface->dns; struct in6_addr addr; size_t rewrite_cnt = iface->dns_cnt; if (rewrite_cnt == 0) { if (odhcpd_get_interface_dns_addr(iface, &addr)) continue; /* Unable to comply */ rewrite = &addr; rewrite_cnt = 1; } /* Copy over any other addresses */ for (size_t i = 0; i < dns_count; ++i) { size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1; dns_ptr[i] = rewrite[j]; } } odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface); } }