blob: d1147ba93f6f403017360ae510049ce6ba0e4332 [file] [log] [blame]
/* dnsmasq is Copyright (c) 2000-2013 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 {
time_t now;
int ind, managed, other, found_context, first;
char *if_name;
struct dhcp_netid *tags;
struct in6_addr link_local, link_global;
unsigned int pref_time, adv_interval;
};
struct search_param {
time_t now; int iface;
char name[IF_NAMESIZE+1];
};
static void send_ra(time_t now, 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 flags,
unsigned int preferred, unsigned int valid, void *vparam);
static int iface_search(struct in6_addr *local, int prefix,
int scope, int if_index, int flags,
int prefered, int valid, void *vparam);
static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm);
static void new_timeout(struct dhcp_context *context, char *iface_name, time_t now);
static unsigned int calc_lifetime(struct ra_interface *ra);
static unsigned int calc_interval(struct ra_interface *ra);
static unsigned int calc_prio(struct ra_interface *ra);
static struct ra_interface *find_iface_param(char *iface);
static int hop_limit;
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->dhcp6; context; context = context->next)
if ((context->flags & CONTEXT_RA_NAME))
break;
/* Need ICMP6 socket for transmission for DHCPv6 even when not doing RA. */
ICMP6_FILTER_SETBLOCKALL(&filter);
if (daemon->doing_ra)
{
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;
if (daemon->doing_ra)
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_short_period_start = context->ra_time = now;
else
for (context = daemon->dhcp6; context; context = context->next)
if (!(context->flags & CONTEXT_TEMPLATE))
{
context->ra_time = now + (rand16()/13000); /* range 0 - 5 */
/* re-do frequently for a minute or so, in case the first gets lost. */
context->ra_short_period_start = now;
}
}
void icmp6_packet(time_t now)
{
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;
/* 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, NULL))
return;
for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
if (tmp->name && wildcard_match(tmp->name, interface))
return;
if (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(now, if_index, interface, !IN6_IS_ADDR_UNSPECIFIED(&from.sin6_addr) ? &from.sin6_addr : NULL);
}
}
static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *dest)
{
struct ra_packet *ra;
struct ra_param parm;
struct sockaddr_in6 addr;
struct dhcp_context *context, *tmp, **up;
struct dhcp_netid iface_id;
struct dhcp_opt *opt_cfg;
struct ra_interface *ra_param = find_iface_param(iface_name);
int done_dns = 0;
#ifdef HAVE_LINUX_NETWORK
FILE *f;
#endif
save_counter(0);
ra = expand(sizeof(struct ra_packet));
ra->type = ND_ROUTER_ADVERT;
ra->code = 0;
ra->hop_limit = hop_limit;
ra->flags = calc_prio(ra_param);
ra->lifetime = htons(calc_lifetime(ra_param));
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;
parm.now = now;
parm.pref_time = 0;
parm.adv_interval = calc_interval(ra_param);
/* set tag with name == interface */
iface_id.net = iface_name;
iface_id.next = NULL;
parm.tags = &iface_id;
for (context = daemon->dhcp6; context; context = context->next)
{
context->flags &= ~CONTEXT_RA_DONE;
context->netid.next = &context->netid;
}
if (!iface_enumerate(AF_INET6, &parm, add_prefixes))
return;
/* Look for constructed contexts associated with addresses which have gone,
and advertise them with preferred_time == 0 RFC 6204 4.3 L-13 */
for (up = &daemon->dhcp6, context = daemon->dhcp6; context; context = tmp)
{
tmp = context->next;
if (context->if_index == iface && (context->flags & CONTEXT_OLD))
{
unsigned int old = difftime(now, context->address_lost_time);
if (old > context->saved_valid)
{
/* We've advertised this enough, time to go */
*up = context->next;
free(context);
}
else
{
struct prefix_opt *opt;
struct in6_addr local = context->start6;
int do_slaac = 0;
parm.found_context = 1;
/* zero net part of address */
setaddr6part(&local, addr6part(&local) & ~((context->prefix == 64) ? (u64)-1LL : (1LLU << (128 - context->prefix)) - 1LLU));
if ((context->flags &
(CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS)))
do_slaac = 1;
if ((opt = expand(sizeof(struct prefix_opt))))
{
opt->type = ICMP6_OPT_PREFIX;
opt->len = 4;
opt->prefix_len = context->prefix;
/* autonomous only if we're not doing dhcp, always set "on-link" */
opt->flags = do_slaac ? 0xC0 : 0x80;
opt->valid_lifetime = htonl(context->saved_valid - old);
opt->preferred_lifetime = htonl(0);
opt->reserved = 0;
opt->prefix = local;
inet_ntop(AF_INET6, &local, daemon->addrbuff, ADDRSTRLEN);
my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s old prefix", iface_name, daemon->addrbuff);
}
up = &context->next;
}
}
else
up = &context->next;
}
if (!parm.found_context)
return;
#ifdef HAVE_LINUX_NETWORK
/* Note that IPv6 MTU is not necessarilly the same as the IPv4 MTU
available from SIOCGIFMTU */
sprintf(daemon->namebuff, "/proc/sys/net/ipv6/conf/%s/mtu", iface_name);
if ((f = fopen(daemon->namebuff, "r")))
{
if (fgets(daemon->namebuff, MAXDNAME, f))
{
put_opt6_char(ICMP6_OPT_MTU);
put_opt6_char(1);
put_opt6_short(0);
put_opt6_long(atoi(daemon->namebuff));
}
fclose(f);
}
#endif
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(parm.adv_interval * 2); /* 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_global, 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(parm.adv_interval * 2); /* 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 (daemon->port == NAMESERVER_PORT && !done_dns)
{
/* default == us, as long as we are supplying DNS service. */
put_opt6_char(ICMP6_OPT_RDNSS);
put_opt6_char(3);
put_opt6_short(0);
put_opt6_long(parm.adv_interval * 2); /* lifetime - twice RA retransmit */
put_opt6(&parm.link_global, 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);
setsockopt(daemon->icmp6fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &iface, sizeof(iface));
}
while (sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(0), 0,
(struct sockaddr *)&addr, sizeof(addr)) == -1 && retry_send());
}
static int add_prefixes(struct in6_addr *local, int prefix,
int scope, int if_index, int flags,
unsigned int preferred, unsigned int valid, void *vparam)
{
struct ra_param *param = vparam;
(void)scope; /* warning */
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_MULTICAST(local))
{
int do_prefix = 0;
int do_slaac = 0;
int deprecate = 0;
int constructed = 0;
unsigned int time = 0xffffffff;
struct dhcp_context *context;
for (context = daemon->dhcp6; context; context = context->next)
if (!(context->flags & (CONTEXT_TEMPLATE | CONTEXT_OLD)) &&
prefix == context->prefix &&
is_same_net6(local, &context->start6, prefix) &&
is_same_net6(local, &context->end6, prefix))
{
context->saved_valid = valid;
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, don't reduce below 3 * RA interval. */
if (time > context->lease_time)
{
time = context->lease_time;
if (time < ((unsigned int)(3 * param->adv_interval)))
time = 3 * param->adv_interval;
}
if (context->flags & CONTEXT_DEPRECATE)
deprecate = 1;
if (context->flags & CONTEXT_CONSTRUCTED)
constructed = 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;
}
/* configured time is ceiling */
if (!constructed || valid > time)
valid = time;
if (flags & IFACE_DEPRECATED)
preferred = 0;
if (deprecate)
time = 0;
/* configured time is ceiling */
if (!constructed || preferred > time)
preferred = time;
if (preferred > param->pref_time)
{
param->pref_time = preferred;
param->link_global = *local;
}
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));
opt->type = ICMP6_OPT_PREFIX;
opt->len = 4;
opt->prefix_len = prefix;
/* autonomous only if we're not doing dhcp, always set "on-link" */
opt->flags = do_slaac ? 0xC0 : 0x80;
opt->valid_lifetime = htonl(valid);
opt->preferred_lifetime = htonl(preferred);
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;
param.now = now;
param.iface = 0;
while (1)
{
/* find overdue events, and time of first future event */
for (next_event = 0, context = daemon->dhcp6; 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;
if ((context->flags & CONTEXT_OLD) &&
context->if_index != 0 &&
indextoname(daemon->icmp6fd, param.iface, param.name))
{
/* A context for an old address. We'll not find the interface by
looking for addresses, but we know it anyway, since the context is
constructed */
param.iface = context->if_index;
new_timeout(context, param.name, now);
}
else if (iface_enumerate(AF_INET6, &param, iface_search))
/* 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. */
context->ra_time = 0;
if (param.iface != 0 &&
iface_check(AF_LOCAL, NULL, param.name, NULL))
{
struct iname *tmp;
for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
if (tmp->name && wildcard_match(tmp->name, param.name))
break;
if (!tmp)
send_ra(now, param.iface, param.name, NULL);
}
}
return next_event;
}
static int iface_search(struct in6_addr *local, int prefix,
int scope, int if_index, int flags,
int preferred, int valid, void *vparam)
{
struct search_param *param = vparam;
struct dhcp_context *context;
(void)scope;
(void)preferred;
(void)valid;
for (context = daemon->dhcp6; context; context = context->next)
if (!(context->flags & (CONTEXT_TEMPLATE | CONTEXT_OLD)) &&
prefix == context->prefix &&
is_same_net6(local, &context->start6, prefix) &&
is_same_net6(local, &context->end6, prefix) &&
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 arrange for RA to be sent unless interface is
still doing DAD.*/
if (!(flags & IFACE_TENTATIVE))
param->iface = if_index;
/* should never fail */
if (!indextoname(daemon->icmp6fd, if_index, param->name))
{
param->iface = 0;
return 0;
}
new_timeout(context, param->name, param->now);
/* zero timers for other contexts on the same subnet, so they don't timeout
independently */
for (context = context->next; context; context = context->next)
if (prefix == context->prefix &&
is_same_net6(local, &context->start6, prefix) &&
is_same_net6(local, &context->end6, prefix))
context->ra_time = 0;
return 0; /* found, abort */
}
return 1; /* keep searching */
}
static void new_timeout(struct dhcp_context *context, char *iface_name, time_t now)
{
if (difftime(now, context->ra_short_period_start) < 60.0)
/* range 5 - 20 */
context->ra_time = now + 5 + (rand16()/4400);
else
{
/* range 3/4 - 1 times MaxRtrAdvInterval */
unsigned int adv_interval = calc_interval(find_iface_param(iface_name));
context->ra_time = now + (3 * adv_interval)/4 + ((adv_interval * (unsigned int)rand16()) >> 18);
}
}
static struct ra_interface *find_iface_param(char *iface)
{
struct ra_interface *ra;
for (ra = daemon->ra_interfaces; ra; ra = ra->next)
if (wildcard_match(ra->name, iface))
return ra;
return NULL;
}
static unsigned int calc_interval(struct ra_interface *ra)
{
int interval = 600;
if (ra && ra->interval != 0)
{
interval = ra->interval;
if (interval > 1800)
interval = 1800;
else if (interval < 4)
interval = 4;
}
return (unsigned int)interval;
}
static unsigned int calc_lifetime(struct ra_interface *ra)
{
int lifetime, interval = (int)calc_interval(ra);
if (!ra || ra->lifetime == -1) /* not specified */
lifetime = 3 * interval;
else
{
lifetime = ra->lifetime;
if (lifetime < interval && lifetime != 0)
lifetime = interval;
else if (lifetime > 9000)
lifetime = 9000;
}
return (unsigned int)lifetime;
}
static unsigned int calc_prio(struct ra_interface *ra)
{
if (ra)
return ra->prio;
return 0;
}
#endif