mirror of
https://github.com/pi-hole/dnsmasq.git
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Router Advertisement
This commit is contained in:
Simon Kelley
433
src/radv.c
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433
src/radv.c
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@@ -0,0 +1,433 @@
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/* dnsmasq is Copyright (c) 2000-2012 Simon Kelley
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 dated June, 1991, or
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(at your option) version 3 dated 29 June, 2007.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* NB. This code may be called during a DHCPv4 transaction which is in ping-wait
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It therefore cannot use any DHCP buffer resources except outpacket, which is
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not used by DHCPv4 code. */
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#include "dnsmasq.h"
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#include <netinet/icmp6.h>
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#ifdef HAVE_DHCP6
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struct ra_param {
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int ind, managed, found_context, first;
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char *if_name;
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struct in6_addr link_local;
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};
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struct search_param {
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time_t now; int iface;
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};
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static void send_ra(int iface, char *iface_name, struct in6_addr *dest);
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static int add_prefixes(struct in6_addr *local, int prefix,
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int scope, int if_index, int dad, void *vparam);
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static int iface_search(struct in6_addr *local, int prefix,
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int scope, int if_index, int dad, void *vparam);
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static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm);
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static int unicast_hop_limit, multicast_hop_limit;
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static time_t ra_short_period_start;
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void ra_init(time_t now)
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{
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struct dhcp_context *context;
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struct icmp6_filter filter;
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int fd;
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#if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
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int class = IPTOS_CLASS_CS6;
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#endif
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int val = 255; /* radvd uses this value */
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size_t len1 = sizeof(int);
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size_t len2 = sizeof(int);
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ICMP6_FILTER_SETBLOCKALL(&filter);
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ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
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ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);
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if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 ||
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getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &unicast_hop_limit, &len1) ||
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getsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &multicast_hop_limit, &len2) ||
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#if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
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setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &class, sizeof(class)) == -1 ||
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#endif
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!fix_fd(fd) ||
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!set_ipv6pktinfo(fd) ||
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setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val)) ||
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setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) ||
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setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filter, sizeof(filter)) == -1)
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die (_("cannot create ICMPv6 socket: %s"), NULL, EC_BADNET);
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daemon->icmp6fd = fd;
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/* link the DHCP6 contexts to the ra-only ones so we can traverse them all
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from ->ra_contexts, but only the non-ra-onlies from ->dhcp6 */
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if (!daemon->ra_contexts)
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daemon->ra_contexts = daemon->dhcp6;
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else
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{
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for (context = daemon->ra_contexts; context->next; context = context->next);
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context->next = daemon->dhcp6;
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}
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if (!daemon->dhcp6)
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die(_("cannot do router advertisement unless DHCPv6 is enabled"), NULL, EC_BADCONF);
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ra_start_unsolicted(now);
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}
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void ra_start_unsolicted(time_t now)
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{
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struct dhcp_context *context;
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/* init timers so that we do ra's for all soon. some ra_times will end up zeroed
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if it's not appropriate to advertise those contexts.
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This gets re-called on a netlink route-change to re-do the advertisement
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and pick up new interfaces */
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/* range 0 - 5 */
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for (context = daemon->ra_contexts; context; context = context->next)
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context->ra_time = now + (rand16()/13000);
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/* re-do ras after a short time, in case the first gets lost.
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This is reset once that's done. */
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ra_short_period_start = now;
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}
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void icmp6_packet(void)
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{
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char interface[IF_NAMESIZE+1];
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ssize_t sz;
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int if_index = 0;
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struct cmsghdr *cmptr;
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struct msghdr msg;
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union {
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struct cmsghdr align; /* this ensures alignment */
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char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
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} control_u;
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struct sockaddr_in6 from;
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unsigned char *p;
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char *mac = "";
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struct iname *tmp;
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struct dhcp_context *context;
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/* Note: use outpacket for input buffer */
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msg.msg_control = control_u.control6;
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msg.msg_controllen = sizeof(control_u);
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msg.msg_flags = 0;
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msg.msg_name = &from;
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msg.msg_namelen = sizeof(from);
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msg.msg_iov = &daemon->outpacket;
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msg.msg_iovlen = 1;
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if ((sz = recv_dhcp_packet(daemon->icmp6fd, &msg)) == -1 || sz < 8)
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return;
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for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
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if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo)
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{
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union {
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unsigned char *c;
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struct in6_pktinfo *p;
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} p;
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p.c = CMSG_DATA(cmptr);
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if_index = p.p->ipi6_ifindex;
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}
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if (!indextoname(daemon->icmp6fd, if_index, interface))
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return;
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if (!iface_check(AF_LOCAL, NULL, interface))
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return;
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for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
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if (tmp->name && (strcmp(tmp->name, interface) == 0))
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return;
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/* weird libvirt-inspired access control */
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for (context = daemon->dhcp6; context; context = context->next)
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if (!context->interface || strcmp(context->interface, interface) == 0)
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break;
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if (!context)
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return;
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p = (unsigned char *)daemon->outpacket.iov_base;
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if (p[0] != ICMP6_ROUTER_SOLICIT || p[1] != 0)
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return;
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/* look for link-layer address option for logging */
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if (sz >= 16 && p[8] == ICMP6_OPT_SOURCE_MAC && (p[9] * 8) + 8 <= sz)
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{
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print_mac(daemon->namebuff, &p[10], (p[9] * 8) - 2);
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mac = daemon->namebuff;
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}
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my_syslog(MS_DHCP | LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac);
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send_ra(if_index, interface, &from.sin6_addr);
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}
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static void send_ra(int iface, char *iface_name, struct in6_addr *dest)
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{
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struct ra_packet *ra;
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struct ra_param parm;
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struct ifreq ifr;
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struct sockaddr_in6 addr;
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struct dhcp_context *context;
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save_counter(0);
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ra = expand(sizeof(struct ra_packet));
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ra->type = ICMP6_ROUTER_ADVERT;
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ra->code = 0;
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ra->hop_limit = dest ? unicast_hop_limit : multicast_hop_limit;
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ra->flags = 0;
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ra->lifetime = htons(1800); /* AdvDefaultLifetime*/
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ra->reachable_time = 0;
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ra->retrans_time = 0;
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parm.ind = iface;
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parm.managed = 0;
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parm.found_context = 0;
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parm.if_name = iface_name;
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parm.first = 1;
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for (context = daemon->ra_contexts; context; context = context->next)
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context->flags &= ~CONTEXT_RA_DONE;
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if (!iface_enumerate(AF_INET6, &parm, add_prefixes) ||
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!parm.found_context)
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return;
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strncpy(ifr.ifr_name, iface_name, IF_NAMESIZE);
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if (ioctl(daemon->icmp6fd, SIOCGIFMTU, &ifr) != -1)
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{
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put_opt6_char(ICMP6_OPT_MTU);
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put_opt6_char(1);
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put_opt6_short(0);
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put_opt6_long(ifr.ifr_mtu);
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}
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iface_enumerate(AF_LOCAL, &iface, add_lla);
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/* RDNSS, RFC 6106 */
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put_opt6_char(ICMP6_OPT_RDNSS);
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put_opt6_char(3);
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put_opt6_short(0);
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put_opt6_long(1800); /* lifetime - twice RA retransmit */
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put_opt6(&parm.link_local, IN6ADDRSZ);
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/* set managed bits unless we're providing only RA on this link */
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if (parm.managed)
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ra->flags = 0xc0;
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/* decide where we're sending */
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memset(&addr, 0, sizeof(addr));
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addr.sin6_family = AF_INET6;
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addr.sin6_port = htons(IPPROTO_ICMPV6);
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if (dest)
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{
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memcpy(&addr.sin6_addr, dest, sizeof(struct in6_addr));
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if (IN6_IS_ADDR_LINKLOCAL(dest) ||
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IN6_IS_ADDR_MC_LINKLOCAL(dest))
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addr.sin6_scope_id = iface;
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}
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else
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inet_pton(AF_INET6, ALL_HOSTS, &addr.sin6_addr);
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send_from(daemon->icmp6fd, 0, daemon->outpacket.iov_base, save_counter(0),
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(union mysockaddr *)&addr, (struct all_addr *)&parm.link_local, iface);
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}
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static int add_prefixes(struct in6_addr *local, int prefix,
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int scope, int if_index, int dad, void *vparam)
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{
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struct dhcp_context *context, *tmp;
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struct ra_param *param = vparam;
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struct prefix_opt *opt;
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(void)scope; /* warning */
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(void)dad;
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if (if_index == param->ind)
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{
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if (IN6_IS_ADDR_LINKLOCAL(local))
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param->link_local = *local;
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else if (!IN6_IS_ADDR_LOOPBACK(local) &&
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!IN6_IS_ADDR_LINKLOCAL(local) &&
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!IN6_IS_ADDR_MULTICAST(local))
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{
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for (context = daemon->ra_contexts; context; context = context->next)
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if (prefix == context->prefix &&
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is_same_net6(local, &context->start6, prefix) &&
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is_same_net6(local, &context->end6, prefix))
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{
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if (!(context->flags & CONTEXT_RA_ONLY))
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param->managed = 1;
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if (context->flags & CONTEXT_RA_DONE)
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continue;
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/* subsequent prefixes on the same interface don't need timers */
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if (!param->first)
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context->ra_time = 0;
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param->first = 0;
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param->found_context = 1;
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context->flags |= CONTEXT_RA_DONE;
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/* mark this subnet and duplicates: as done. */
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for (tmp = context->next; tmp; tmp = tmp->next)
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if (tmp->prefix == prefix &&
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is_same_net6(local, &tmp->start6, prefix) &&
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is_same_net6(local, &tmp->end6, prefix))
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{
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tmp->flags |= CONTEXT_RA_DONE;
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context->ra_time = 0;
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}
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if ((opt = expand(sizeof(struct prefix_opt))))
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{
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u64 addrpart = addr6part(&context->start6);
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u64 mask = (prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU;
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unsigned int time = context->lease_time;
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/* lifetimes must be min 2 hrs, by RFC 2462 */
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if (time < 7200)
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time = 7200;
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opt->type = ICMP6_OPT_PREFIX;
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opt->len = 4;
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opt->prefix_len = prefix;
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/* autonomous only is we're not doing dhcp */
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opt->flags = (context->flags & CONTEXT_RA_ONLY) ? 0xc0 : 0x00;
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opt->valid_lifetime = opt->preferred_lifetime = htonl(time);
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opt->reserved = 0;
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opt->prefix = context->start6;
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setaddr6part(&opt->prefix, addrpart & ~mask);
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inet_ntop(AF_INET6, &opt->prefix, daemon->addrbuff, ADDRSTRLEN);
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my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff);
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}
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}
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}
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}
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return 1;
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}
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static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm)
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{
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(void)type;
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if (index == *((int *)parm))
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{
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/* size is in units of 8 octets and includes type and length (2 bytes)
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add 7 to round up */
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int len = (maclen + 9) >> 3;
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unsigned char *p = expand(len << 3);
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memset(p, 0, len << 3);
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*p++ = ICMP6_OPT_SOURCE_MAC;
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*p++ = len;
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memcpy(p, mac, maclen);
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return 0;
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}
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return 1;
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}
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time_t periodic_ra(time_t now)
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{
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struct search_param param;
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struct dhcp_context *context;
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time_t next_event;
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char interface[IF_NAMESIZE+1];
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param.now = now;
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while (1)
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{
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/* find overdue events, and time of first future event */
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for (next_event = 0, context = daemon->ra_contexts; context; context = context->next)
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if (context->ra_time != 0)
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{
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if (difftime(context->ra_time, now) < 0.0)
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break; /* overdue */
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if (next_event == 0 || difftime(next_event, context->ra_time + 2) > 0.0)
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next_event = context->ra_time + 2;
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}
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/* none overdue */
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if (!context)
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break;
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/* There's a context overdue, but we can't find an interface
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associated with it, because it's for a subnet we dont
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have an interface on. Probably we're doing DHCP on
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a remote subnet via a relay. Zero the timer, since we won't
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ever be able to send ra's and satistfy it. */
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if (iface_enumerate(AF_INET6, ¶m, iface_search))
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context->ra_time = 0;
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else if (indextoname(daemon->icmp6fd, param.iface, interface))
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send_ra(param.iface, interface, NULL);
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}
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return next_event;
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}
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static int iface_search(struct in6_addr *local, int prefix,
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int scope, int if_index, int dad, void *vparam)
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{
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struct search_param *param = vparam;
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struct dhcp_context *context, *tmp;
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(void)scope;
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(void)dad;
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for (context = daemon->ra_contexts; context; context = context->next)
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if (prefix == context->prefix &&
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is_same_net6(local, &context->start6, prefix) &&
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is_same_net6(local, &context->end6, prefix))
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if (context->ra_time != 0 && difftime(context->ra_time, param->now) < 0.0)
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{
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/* found an interface that's overdue for RA determine new
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timeout value and zap other contexts on the same interface
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so they don't timeout independently .*/
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param->iface = if_index;
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if (difftime(param->now, ra_short_period_start) < 60.0)
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/* range 5 - 20 */
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context->ra_time = param->now + 5 + (rand16()/4400);
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else
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/* range 450 - 600 */
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context->ra_time = param->now + 450 + (rand16()/440);
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return 0; /* found, abort */
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}
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return 1; /* keep searching */
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}
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||||
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||||
#endif
|
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