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Check assumed SLAAC addresses by pinging them.
This commit is contained in:
Simon Kelley
243
src/slaac.c
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243
src/slaac.c
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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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#include "dnsmasq.h"
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#ifdef HAVE_DHCP6
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#include <netinet/icmp6.h>
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static int map_rebuild = 0;
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static int ping_id = 0;
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void slaac_add_addrs(struct dhcp_lease *lease, time_t now)
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{
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struct slaac_address *slaac, *old, **up;
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struct dhcp_context *context;
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if (!(lease->flags & LEASE_HAVE_HWADDR) ||
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lease->last_interface == 0 ||
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!lease->hostname)
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return ;
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old = lease->slaac_address;
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lease->slaac_address = NULL;
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for (context = daemon->ra_contexts; context; context = context->next)
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if ((context->flags & CONTEXT_RA_NAME) && lease->last_interface == context->if_index)
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{
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struct in6_addr addr = context->start6;
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if (lease->hwaddr_len == 6 &&
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(lease->hwaddr_type == ARPHRD_ETHER || lease->hwaddr_type == ARPHRD_IEEE802))
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{
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/* convert MAC address to EUI-64 */
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memcpy(&addr.s6_addr[8], lease->hwaddr, 3);
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memcpy(&addr.s6_addr[13], &lease->hwaddr[3], 3);
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addr.s6_addr[11] = 0xff;
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addr.s6_addr[12] = 0xfe;
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}
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#if defined(ARPHRD_EUI64)
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else if (lease->hwaddr_len == 8 &&
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lease->hwaddr_type == ARPHRD_EUI64)
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memcpy(&addr.s6_addr[8], lease->hwaddr, 8);
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#endif
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#if defined(ARPHRD_IEEE1394) && defined(ARPHRD_EUI64)
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else if (lease->clid_len == 9 &&
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lease->clid[0] == ARPHRD_EUI64 &&
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lease->hwaddr_type == ARPHRD_IEEE1394)
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/* firewire has EUI-64 identifier as clid */
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memcpy(&addr.s6_addr[8], &lease->clid[1], 8);
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#endif
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else
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continue;
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addr.s6_addr[8] ^= 0x02;
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/* check if we already have this one */
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for (up = &old, slaac = old; slaac; slaac = slaac->next)
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{
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if (IN6_ARE_ADDR_EQUAL(&addr, &slaac->addr))
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{
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*up = slaac->next;
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break;
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}
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up = &slaac->next;
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}
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/* No, make new one */
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if (!slaac && (slaac = whine_malloc(sizeof(struct slaac_address))))
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{
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slaac->ping_time = now;
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slaac->backoff = 1;
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slaac->addr = addr;
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slaac->local = context->local6;
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/* Do RA's to prod it */
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ra_start_unsolicted(now, context);
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}
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if (slaac)
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{
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slaac->next = lease->slaac_address;
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lease->slaac_address = slaac;
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}
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}
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/* Free any no reused */
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for (; old; old = slaac)
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{
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slaac = old->next;
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free(old);
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}
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}
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time_t periodic_slaac(time_t now, struct dhcp_lease *leases)
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{
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struct dhcp_context *context;
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struct dhcp_lease *lease;
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struct slaac_address *slaac;
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time_t next_event = 0;
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for (context = daemon->ra_contexts; context; context = context->next)
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if ((context->flags & CONTEXT_RA_NAME))
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break;
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/* nothing configured */
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if (!context)
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return 0;
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while (ping_id == 0)
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ping_id = rand16();
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if (map_rebuild)
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{
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map_rebuild = 0;
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build_subnet_map();
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}
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for (lease = leases; lease; lease = lease->next)
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for (slaac = lease->slaac_address; slaac; slaac = slaac->next)
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{
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/* confirmed? */
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if (slaac->backoff == 0)
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continue;
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if (difftime(slaac->ping_time, now) <= 0.0)
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{
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struct ping_packet *ping;
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struct sockaddr_in6 addr;
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save_counter(0);
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ping = expand(sizeof(struct ping_packet));
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ping->type = ICMP6_ECHO_REQUEST;
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ping->code = 0;
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ping->identifier = ping_id;
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ping->sequence_no = slaac->backoff;
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memset(&addr, 0, sizeof(addr));
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#ifdef HAVE_SOCKADDR_SA_LEN
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addr.sin6_len = sizeof(struct sockaddr_in6);
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#endif
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addr.sin6_family = AF_INET6;
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addr.sin6_port = htons(IPPROTO_ICMPV6);
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addr.sin6_addr = slaac->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 *)&slaac->local, lease->last_interface);
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slaac->ping_time += (1 << (slaac->backoff - 1)) + (rand16()/21785); /* 0 - 3 */
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if (slaac->backoff > 4)
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slaac->ping_time += rand16()/4000; /* 0 - 15 */
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slaac->backoff++;
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}
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if (next_event == 0 || difftime(next_event, slaac->ping_time) >= 0.0)
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next_event = slaac->ping_time;
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}
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return next_event;
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}
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void slaac_ping_reply(struct in6_addr *sender, unsigned char *packet, char *interface, struct dhcp_lease *leases)
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{
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struct dhcp_lease *lease;
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struct slaac_address *slaac;
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struct ping_packet *ping = (struct ping_packet *)packet;
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int gotone = 0;
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if (ping->identifier == ping_id)
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for (lease = leases; lease; lease = lease->next)
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for (slaac = lease->slaac_address; slaac; slaac = slaac->next)
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if (slaac->backoff != 0 && IN6_ARE_ADDR_EQUAL(sender, &slaac->addr))
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{
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slaac->backoff = 0;
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gotone = 1;
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inet_ntop(AF_INET6, sender, daemon->addrbuff, ADDRSTRLEN);
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my_syslog(MS_DHCP | LOG_INFO, "SLAAC-CONFIRM(%s) %s %s", interface, daemon->addrbuff, lease->hostname);
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}
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lease_update_dns(gotone);
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}
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/* Build a map from ra-names subnets to corresponding interfaces. This
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is used to go from DHCPv4 leases to SLAAC addresses,
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interface->IPv6-subnet, IPv6-subnet + MAC address -> SLAAC.
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*/
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static int add_subnet(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;
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(void)scope;
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(void)dad;
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(void)vparam;
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for (context = daemon->ra_contexts; context; context = context->next)
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if ((context->flags & CONTEXT_RA_NAME) &&
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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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context->if_index = if_index;
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context->local6 = *local;
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}
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return 1;
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}
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void build_subnet_map(void)
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{
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struct dhcp_context *context;
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int ok = 0;
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for (context = daemon->ra_contexts; context; context = context->next)
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{
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context->if_index = 0;
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if ((context->flags & CONTEXT_RA_NAME))
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ok = 1;
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}
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/* ra-names configured */
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if (ok)
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iface_enumerate(AF_INET6, NULL, add_subnet);
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}
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void schedule_subnet_map(void)
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{
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map_rebuild = 1;
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}
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#endif
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