| /* dnsmasq is Copyright (c) 2000-2012 Simon Kelley |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; version 2 dated June, 1991, or |
| (at your option) version 3 dated 29 June, 2007. |
| |
| 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| |
| /* NB. This code may be called during a DHCPv4 or transaction which is in ping-wait |
| It therefore cannot use any DHCP buffer resources except outpacket, which is |
| not used by DHCPv4 code. This code may also be called when DHCP 4 or 6 isn't |
| active, so we ensure that outpacket is allocated here too */ |
| |
| #include "dnsmasq.h" |
| |
| #ifdef HAVE_DHCP6 |
| |
| #include <netinet/icmp6.h> |
| |
| struct ra_param { |
| int ind, managed, other, found_context, first; |
| char *if_name; |
| struct dhcp_netid *tags; |
| struct in6_addr link_local; |
| }; |
| |
| struct search_param { |
| time_t now; int iface; |
| }; |
| |
| static void send_ra(int iface, char *iface_name, struct in6_addr *dest); |
| static int add_prefixes(struct in6_addr *local, int prefix, |
| int scope, int if_index, int dad, void *vparam); |
| static int iface_search(struct in6_addr *local, int prefix, |
| int scope, int if_index, int dad, void *vparam); |
| static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm); |
| |
| static int hop_limit; |
| static time_t ra_short_period_start; |
| |
| void ra_init(time_t now) |
| { |
| struct icmp6_filter filter; |
| int fd; |
| #if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6) |
| int class = IPTOS_CLASS_CS6; |
| #endif |
| int val = 255; /* radvd uses this value */ |
| socklen_t len = sizeof(int); |
| struct dhcp_context *context; |
| |
| /* ensure this is around even if we're not doing DHCPv6 */ |
| expand_buf(&daemon->outpacket, sizeof(struct dhcp_packet)); |
| |
| /* See if we're guessing SLAAC addresses, if so we need to recieve ping replies */ |
| for (context = daemon->ra_contexts; context; context = context->next) |
| if ((context->flags & CONTEXT_RA_NAME)) |
| break; |
| |
| ICMP6_FILTER_SETBLOCKALL(&filter); |
| ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter); |
| if (context) |
| ICMP6_FILTER_SETPASS(ICMP6_ECHO_REPLY, &filter); |
| |
| if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 || |
| getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hop_limit, &len) || |
| #if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6) |
| setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &class, sizeof(class)) == -1 || |
| #endif |
| !fix_fd(fd) || |
| !set_ipv6pktinfo(fd) || |
| setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val)) || |
| setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) || |
| setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filter, sizeof(filter)) == -1) |
| die (_("cannot create ICMPv6 socket: %s"), NULL, EC_BADNET); |
| |
| daemon->icmp6fd = fd; |
| |
| ra_start_unsolicted(now, NULL); |
| } |
| |
| void ra_start_unsolicted(time_t now, struct dhcp_context *context) |
| { |
| /* init timers so that we do ra's for some/all soon. some ra_times will end up zeroed |
| if it's not appropriate to advertise those contexts. |
| This gets re-called on a netlink route-change to re-do the advertisement |
| and pick up new interfaces */ |
| |
| if (context) |
| context->ra_time = now; |
| else |
| for (context = daemon->ra_contexts; context; context = context->next) |
| context->ra_time = now + (rand16()/13000); /* range 0 - 5 */ |
| |
| /* re-do frequently for a minute or so, in case the first gets lost. */ |
| ra_short_period_start = now; |
| } |
| |
| void icmp6_packet(void) |
| { |
| char interface[IF_NAMESIZE+1]; |
| ssize_t sz; |
| int if_index = 0; |
| struct cmsghdr *cmptr; |
| struct msghdr msg; |
| union { |
| struct cmsghdr align; /* this ensures alignment */ |
| char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
| } control_u; |
| struct sockaddr_in6 from; |
| unsigned char *packet; |
| struct iname *tmp; |
| struct dhcp_context *context; |
| |
| /* Note: use outpacket for input buffer */ |
| msg.msg_control = control_u.control6; |
| msg.msg_controllen = sizeof(control_u); |
| msg.msg_flags = 0; |
| msg.msg_name = &from; |
| msg.msg_namelen = sizeof(from); |
| msg.msg_iov = &daemon->outpacket; |
| msg.msg_iovlen = 1; |
| |
| if ((sz = recv_dhcp_packet(daemon->icmp6fd, &msg)) == -1 || sz < 8) |
| return; |
| |
| packet = (unsigned char *)daemon->outpacket.iov_base; |
| |
| for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo) |
| { |
| union { |
| unsigned char *c; |
| struct in6_pktinfo *p; |
| } p; |
| p.c = CMSG_DATA(cmptr); |
| |
| if_index = p.p->ipi6_ifindex; |
| } |
| |
| if (!indextoname(daemon->icmp6fd, if_index, interface)) |
| return; |
| |
| if (!iface_check(AF_LOCAL, NULL, interface)) |
| return; |
| |
| for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next) |
| if (tmp->name && (strcmp(tmp->name, interface) == 0)) |
| return; |
| |
| /* weird libvirt-inspired access control */ |
| for (context = daemon->ra_contexts ? daemon->ra_contexts : daemon->dhcp6; |
| context; context = context->next) |
| if (!context->interface || strcmp(context->interface, interface) == 0) |
| break; |
| |
| if (!context || packet[1] != 0) |
| return; |
| |
| if (packet[0] == ICMP6_ECHO_REPLY) |
| lease_ping_reply(&from.sin6_addr, packet, interface); |
| else if (packet[0] == ND_ROUTER_SOLICIT) |
| { |
| char *mac = ""; |
| |
| /* look for link-layer address option for logging */ |
| if (sz >= 16 && packet[8] == ICMP6_OPT_SOURCE_MAC && (packet[9] * 8) + 8 <= sz) |
| { |
| print_mac(daemon->namebuff, &packet[10], (packet[9] * 8) - 2); |
| mac = daemon->namebuff; |
| } |
| |
| my_syslog(MS_DHCP | LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac); |
| /* source address may not be valid in solicit request. */ |
| send_ra(if_index, interface, !IN6_IS_ADDR_UNSPECIFIED(&from.sin6_addr) ? &from.sin6_addr : NULL); |
| } |
| } |
| |
| static void send_ra(int iface, char *iface_name, struct in6_addr *dest) |
| { |
| struct ra_packet *ra; |
| struct ra_param parm; |
| struct ifreq ifr; |
| struct sockaddr_in6 addr; |
| struct dhcp_context *context; |
| struct dhcp_netid iface_id; |
| struct dhcp_opt *opt_cfg; |
| int done_dns = 0; |
| |
| save_counter(0); |
| ra = expand(sizeof(struct ra_packet)); |
| |
| ra->type = ND_ROUTER_ADVERT; |
| ra->code = 0; |
| ra->hop_limit = hop_limit; |
| ra->flags = 0x00; |
| ra->lifetime = htons(1800); /* AdvDefaultLifetime*/ |
| ra->reachable_time = 0; |
| ra->retrans_time = 0; |
| |
| parm.ind = iface; |
| parm.managed = 0; |
| parm.other = 0; |
| parm.found_context = 0; |
| parm.if_name = iface_name; |
| parm.first = 1; |
| |
| /* set tag with name == interface */ |
| iface_id.net = iface_name; |
| iface_id.next = NULL; |
| parm.tags = &iface_id; |
| |
| for (context = daemon->ra_contexts; context; context = context->next) |
| { |
| context->flags &= ~CONTEXT_RA_DONE; |
| context->netid.next = &context->netid; |
| } |
| |
| if (!iface_enumerate(AF_INET6, &parm, add_prefixes) || |
| !parm.found_context) |
| return; |
| |
| strncpy(ifr.ifr_name, iface_name, IF_NAMESIZE); |
| |
| if (ioctl(daemon->icmp6fd, SIOCGIFMTU, &ifr) != -1) |
| { |
| put_opt6_char(ICMP6_OPT_MTU); |
| put_opt6_char(1); |
| put_opt6_short(0); |
| put_opt6_long(ifr.ifr_mtu); |
| } |
| |
| iface_enumerate(AF_LOCAL, &iface, add_lla); |
| |
| /* RDNSS, RFC 6106, use relevant DHCP6 options */ |
| (void)option_filter(parm.tags, NULL, daemon->dhcp_opts6); |
| |
| for (opt_cfg = daemon->dhcp_opts6; opt_cfg; opt_cfg = opt_cfg->next) |
| { |
| int i; |
| |
| /* netids match and not encapsulated? */ |
| if (!(opt_cfg->flags & DHOPT_TAGOK)) |
| continue; |
| |
| if (opt_cfg->opt == OPTION6_DNS_SERVER) |
| { |
| struct in6_addr *a = (struct in6_addr *)opt_cfg->val; |
| |
| done_dns = 1; |
| if (opt_cfg->len == 0) |
| continue; |
| |
| put_opt6_char(ICMP6_OPT_RDNSS); |
| put_opt6_char((opt_cfg->len/8) + 1); |
| put_opt6_short(0); |
| put_opt6_long(1800); /* lifetime - twice RA retransmit */ |
| /* zero means "self" */ |
| for (i = 0; i < opt_cfg->len; i += IN6ADDRSZ, a++) |
| if (IN6_IS_ADDR_UNSPECIFIED(a)) |
| put_opt6(&parm.link_local, IN6ADDRSZ); |
| else |
| put_opt6(a, IN6ADDRSZ); |
| } |
| |
| if (opt_cfg->opt == OPTION6_DOMAIN_SEARCH && opt_cfg->len != 0) |
| { |
| int len = ((opt_cfg->len+7)/8); |
| |
| put_opt6_char(ICMP6_OPT_DNSSL); |
| put_opt6_char(len + 1); |
| put_opt6_short(0); |
| put_opt6_long(1800); /* lifetime - twice RA retransmit */ |
| put_opt6(opt_cfg->val, opt_cfg->len); |
| |
| /* pad */ |
| for (i = opt_cfg->len; i < len * 8; i++) |
| put_opt6_char(0); |
| } |
| } |
| |
| if (!done_dns) |
| { |
| /* default == us. */ |
| put_opt6_char(ICMP6_OPT_RDNSS); |
| put_opt6_char(3); |
| put_opt6_short(0); |
| put_opt6_long(1800); /* lifetime - twice RA retransmit */ |
| put_opt6(&parm.link_local, IN6ADDRSZ); |
| } |
| |
| /* set managed bits unless we're providing only RA on this link */ |
| if (parm.managed) |
| ra->flags |= 0x80; /* M flag, managed, */ |
| if (parm.other) |
| ra->flags |= 0x40; /* O flag, other */ |
| |
| /* decide where we're sending */ |
| memset(&addr, 0, sizeof(addr)); |
| #ifdef HAVE_SOCKADDR_SA_LEN |
| addr.sin6_len = sizeof(struct sockaddr_in6); |
| #endif |
| addr.sin6_family = AF_INET6; |
| addr.sin6_port = htons(IPPROTO_ICMPV6); |
| if (dest) |
| { |
| addr.sin6_addr = *dest; |
| if (IN6_IS_ADDR_LINKLOCAL(dest) || |
| IN6_IS_ADDR_MC_LINKLOCAL(dest)) |
| addr.sin6_scope_id = iface; |
| } |
| else |
| inet_pton(AF_INET6, ALL_NODES, &addr.sin6_addr); |
| |
| send_from(daemon->icmp6fd, 0, daemon->outpacket.iov_base, save_counter(0), |
| (union mysockaddr *)&addr, (struct all_addr *)&parm.link_local, iface); |
| |
| } |
| |
| static int add_prefixes(struct in6_addr *local, int prefix, |
| int scope, int if_index, int dad, void *vparam) |
| { |
| struct ra_param *param = vparam; |
| |
| (void)scope; /* warning */ |
| (void)dad; |
| |
| if (if_index == param->ind) |
| { |
| if (IN6_IS_ADDR_LINKLOCAL(local)) |
| param->link_local = *local; |
| else if (!IN6_IS_ADDR_LOOPBACK(local) && |
| !IN6_IS_ADDR_LINKLOCAL(local) && |
| !IN6_IS_ADDR_MULTICAST(local)) |
| { |
| int do_prefix = 0; |
| int do_slaac = 0; |
| int deprecate = 0; |
| unsigned int time = 0xffffffff; |
| struct dhcp_context *context; |
| |
| for (context = daemon->ra_contexts; context; context = context->next) |
| if (prefix == context->prefix && |
| is_same_net6(local, &context->start6, prefix) && |
| is_same_net6(local, &context->end6, prefix)) |
| { |
| if ((context->flags & |
| (CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS))) |
| { |
| do_slaac = 1; |
| if (context->flags & CONTEXT_DHCP) |
| { |
| param->other = 1; |
| if (!(context->flags & CONTEXT_RA_STATELESS)) |
| param->managed = 1; |
| } |
| } |
| else |
| { |
| /* don't do RA for non-ra-only unless --enable-ra is set */ |
| if (!option_bool(OPT_RA)) |
| continue; |
| param->managed = 1; |
| param->other = 1; |
| } |
| |
| /* find floor time */ |
| if (time > context->lease_time) |
| time = context->lease_time; |
| |
| if (context->flags & CONTEXT_DEPRECATE) |
| deprecate = 1; |
| |
| /* collect dhcp-range tags */ |
| if (context->netid.next == &context->netid && context->netid.net) |
| { |
| context->netid.next = param->tags; |
| param->tags = &context->netid; |
| } |
| |
| /* subsequent prefixes on the same interface |
| and subsequent instances of this prefix don't need timers. |
| Be careful not to find the same prefix twice with different |
| addresses. */ |
| if (!(context->flags & CONTEXT_RA_DONE)) |
| { |
| if (!param->first) |
| context->ra_time = 0; |
| context->flags |= CONTEXT_RA_DONE; |
| do_prefix = 1; |
| } |
| |
| param->first = 0; |
| param->found_context = 1; |
| } |
| |
| if (do_prefix) |
| { |
| struct prefix_opt *opt; |
| |
| if ((opt = expand(sizeof(struct prefix_opt)))) |
| { |
| /* zero net part of address */ |
| setaddr6part(local, addr6part(local) & ~((prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU)); |
| |
| /* lifetimes must be min 2 hrs, by RFC 2462 */ |
| if (time < 7200) |
| time = 7200; |
| |
| opt->type = ICMP6_OPT_PREFIX; |
| opt->len = 4; |
| opt->prefix_len = prefix; |
| /* autonomous only if we're not doing dhcp */ |
| opt->flags = do_slaac ? 0x40 : 0x00; |
| opt->valid_lifetime = htonl(time); |
| opt->preferred_lifetime = htonl(deprecate ? 0 : time); |
| opt->reserved = 0; |
| opt->prefix = *local; |
| |
| inet_ntop(AF_INET6, local, daemon->addrbuff, ADDRSTRLEN); |
| my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff); |
| } |
| } |
| } |
| } |
| return 1; |
| } |
| |
| static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm) |
| { |
| (void)type; |
| |
| if (index == *((int *)parm)) |
| { |
| /* size is in units of 8 octets and includes type and length (2 bytes) |
| add 7 to round up */ |
| int len = (maclen + 9) >> 3; |
| unsigned char *p = expand(len << 3); |
| memset(p, 0, len << 3); |
| *p++ = ICMP6_OPT_SOURCE_MAC; |
| *p++ = len; |
| memcpy(p, mac, maclen); |
| |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| time_t periodic_ra(time_t now) |
| { |
| struct search_param param; |
| struct dhcp_context *context; |
| time_t next_event; |
| char interface[IF_NAMESIZE+1]; |
| |
| param.now = now; |
| |
| while (1) |
| { |
| /* find overdue events, and time of first future event */ |
| for (next_event = 0, context = daemon->ra_contexts; context; context = context->next) |
| if (context->ra_time != 0) |
| { |
| if (difftime(context->ra_time, now) <= 0.0) |
| break; /* overdue */ |
| |
| if (next_event == 0 || difftime(next_event, context->ra_time) > 0.0) |
| next_event = context->ra_time; |
| } |
| |
| /* none overdue */ |
| if (!context) |
| break; |
| |
| /* There's a context overdue, but we can't find an interface |
| associated with it, because it's for a subnet we dont |
| have an interface on. Probably we're doing DHCP on |
| a remote subnet via a relay. Zero the timer, since we won't |
| ever be able to send ra's and satistfy it. */ |
| if (iface_enumerate(AF_INET6, ¶m, iface_search)) |
| context->ra_time = 0; |
| else if (indextoname(daemon->icmp6fd, param.iface, interface)) |
| send_ra(param.iface, interface, NULL); |
| } |
| |
| return next_event; |
| } |
| |
| static int iface_search(struct in6_addr *local, int prefix, |
| int scope, int if_index, int dad, void *vparam) |
| { |
| struct search_param *param = vparam; |
| struct dhcp_context *context; |
| |
| (void)scope; |
| (void)dad; |
| |
| for (context = daemon->ra_contexts; context; context = context->next) |
| if (prefix == context->prefix && |
| is_same_net6(local, &context->start6, prefix) && |
| is_same_net6(local, &context->end6, prefix)) |
| if (context->ra_time != 0 && difftime(context->ra_time, param->now) <= 0.0) |
| { |
| /* found an interface that's overdue for RA determine new |
| timeout value and zap other contexts on the same interface |
| so they don't timeout independently .*/ |
| param->iface = if_index; |
| |
| if (difftime(param->now, ra_short_period_start) < 60.0) |
| /* range 5 - 20 */ |
| context->ra_time = param->now + 5 + (rand16()/4400); |
| else |
| /* range 450 - 600 */ |
| context->ra_time = param->now + 450 + (rand16()/440); |
| |
| return 0; /* found, abort */ |
| } |
| |
| return 1; /* keep searching */ |
| } |
| |
| |
| #endif |