3b015d40c1
Router Discovery is a core part of IPv6, which by default is handled by the kernel. However, the kernel implementation is meant as a fall-back, and to fully support the protocol a userspace implementation is desired. The protocol essentially listens for Router Advertisement packets from routers on the local link and use these to configure the client automatically. The four main pieces of information are: what kind (if any) of DHCPv6 configuration should be performed; a default gateway; the prefixes that should be considered to be on the local link; and the prefixes with which we can preform SLAAC in order to pick a global IPv6 address. A lot of additional information is also available, which we do not yet fully support, but which will eventually allow us to avoid the need for DHCPv6 in the common case. Short-term, the reason for wanting this is in userspace was the desire to fully track all the addresses on links we manage, and that is not possible for addresses managed by the kernel (as the kernel does not expose to us the fact that it manages these addresses). Moreover, we would like to support stable privacy addresses, which will soon be mandated and the legacy MAC-based global addresses deprecated, to do this well we need to handle the generation in userspace. Lastly, more long-term we wish to support more RA options than what the kernel exposes.
248 lines
8.4 KiB
C
248 lines
8.4 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright (C) 2014 Intel Corporation. All rights reserved.
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <netinet/ether.h>
|
|
#include <netinet/icmp6.h>
|
|
#include <linux/if.h>
|
|
|
|
#include "sd-ndisc.h"
|
|
|
|
#include "networkd-link.h"
|
|
|
|
static int ndisc_netlink_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
|
|
_cleanup_link_unref_ Link *link = userdata;
|
|
int r;
|
|
|
|
assert(link);
|
|
assert(link->ndisc_messages > 0);
|
|
|
|
link->ndisc_messages --;
|
|
|
|
r = sd_netlink_message_get_errno(m);
|
|
if (r < 0 && r != -EEXIST) {
|
|
log_link_error_errno(link, r, "Could not set NDisc route or address: %m");
|
|
link_enter_failed(link);
|
|
}
|
|
|
|
if (link->ndisc_messages == 0) {
|
|
link->ndisc_configured = true;
|
|
link_check_ready(link);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void ndisc_prefix_autonomous_handler(sd_ndisc *nd, const struct in6_addr *prefix, unsigned prefixlen,
|
|
unsigned lifetime_preferred, unsigned lifetime_valid, void *userdata) {
|
|
_cleanup_address_free_ Address *address = NULL;
|
|
Link *link = userdata;
|
|
usec_t time_now;
|
|
int r;
|
|
|
|
assert(nd);
|
|
assert(link);
|
|
assert(link->network);
|
|
|
|
if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
|
|
return;
|
|
|
|
r = address_new(&address);
|
|
if (r < 0) {
|
|
log_link_error_errno(link, r, "Could not allocate address: %m");
|
|
return;
|
|
}
|
|
|
|
assert_se(sd_event_now(link->manager->event, clock_boottime_or_monotonic(), &time_now) >= 0);
|
|
|
|
address->family = AF_INET6;
|
|
address->in_addr.in6 = *prefix;
|
|
if (in_addr_is_null(AF_INET6, (const union in_addr_union *) &link->network->ipv6_token) == 0)
|
|
memcpy(&address->in_addr.in6 + 8, &link->network->ipv6_token + 8, 8);
|
|
else {
|
|
/* see RFC4291 section 2.5.1 */
|
|
address->in_addr.in6.__in6_u.__u6_addr8[8] = link->mac.ether_addr_octet[0];
|
|
address->in_addr.in6.__in6_u.__u6_addr8[8] ^= 1 << 1;
|
|
address->in_addr.in6.__in6_u.__u6_addr8[9] = link->mac.ether_addr_octet[1];
|
|
address->in_addr.in6.__in6_u.__u6_addr8[10] = link->mac.ether_addr_octet[2];
|
|
address->in_addr.in6.__in6_u.__u6_addr8[11] = 0xff;
|
|
address->in_addr.in6.__in6_u.__u6_addr8[12] = 0xfe;
|
|
address->in_addr.in6.__in6_u.__u6_addr8[13] = link->mac.ether_addr_octet[3];
|
|
address->in_addr.in6.__in6_u.__u6_addr8[14] = link->mac.ether_addr_octet[4];
|
|
address->in_addr.in6.__in6_u.__u6_addr8[15] = link->mac.ether_addr_octet[5];
|
|
}
|
|
address->prefixlen = prefixlen;
|
|
address->flags = IFA_F_NOPREFIXROUTE;
|
|
address->cinfo.ifa_prefered = lifetime_preferred;
|
|
address->cinfo.ifa_valid = lifetime_valid;
|
|
|
|
r = address_configure(address, link, ndisc_netlink_handler, true);
|
|
if (r < 0) {
|
|
log_link_warning_errno(link, r, "Could not set SLAAC address: %m");
|
|
link_enter_failed(link);
|
|
return;
|
|
}
|
|
|
|
link->ndisc_messages ++;
|
|
}
|
|
|
|
static void ndisc_prefix_onlink_handler(sd_ndisc *nd, const struct in6_addr *prefix, unsigned prefixlen, unsigned lifetime, void *userdata) {
|
|
_cleanup_route_free_ Route *route = NULL;
|
|
Link *link = userdata;
|
|
usec_t time_now;
|
|
int r;
|
|
|
|
assert(nd);
|
|
assert(link);
|
|
|
|
if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
|
|
return;
|
|
|
|
r = route_new(&route);
|
|
if (r < 0) {
|
|
log_link_error_errno(link, r, "Could not allocate route: %m");
|
|
return;
|
|
}
|
|
|
|
assert_se(sd_event_now(link->manager->event, clock_boottime_or_monotonic(), &time_now) >= 0);
|
|
|
|
route->family = AF_INET6;
|
|
route->table = RT_TABLE_MAIN;
|
|
route->protocol = RTPROT_RA;
|
|
route->flags = RTM_F_PREFIX;
|
|
route->dst.in6 = *prefix;
|
|
route->dst_prefixlen = prefixlen;
|
|
route->lifetime = time_now + lifetime * USEC_PER_SEC;
|
|
|
|
r = route_configure(route, link, ndisc_netlink_handler);
|
|
if (r < 0) {
|
|
log_link_warning_errno(link, r, "Could not set prefix route: %m");
|
|
link_enter_failed(link);
|
|
return;
|
|
}
|
|
|
|
link->ndisc_messages ++;
|
|
}
|
|
|
|
static void ndisc_router_handler(sd_ndisc *nd, uint8_t flags, const struct in6_addr *gateway, unsigned lifetime, int pref, void *userdata) {
|
|
_cleanup_route_free_ Route *route = NULL;
|
|
Link *link = userdata;
|
|
usec_t time_now;
|
|
int r;
|
|
|
|
assert(link);
|
|
assert(link->network);
|
|
assert(link->manager);
|
|
|
|
if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
|
|
return;
|
|
|
|
if (flags & (ND_RA_FLAG_MANAGED | ND_RA_FLAG_OTHER)) {
|
|
if (flags & ND_RA_FLAG_MANAGED)
|
|
dhcp6_request_address(link);
|
|
|
|
r = sd_dhcp6_client_start(link->dhcp6_client);
|
|
if (r < 0 && r != -EALREADY)
|
|
log_link_warning_errno(link, r, "Starting DHCPv6 client on NDisc request failed: %m");
|
|
}
|
|
|
|
if (!gateway)
|
|
return;
|
|
|
|
r = route_new(&route);
|
|
if (r < 0) {
|
|
log_link_error_errno(link, r, "Could not allocate route: %m");
|
|
return;
|
|
}
|
|
|
|
assert_se(sd_event_now(link->manager->event, clock_boottime_or_monotonic(), &time_now) >= 0);
|
|
|
|
route->family = AF_INET6;
|
|
route->table = RT_TABLE_MAIN;
|
|
route->protocol = RTPROT_RA;
|
|
route->pref = pref;
|
|
route->gw.in6 = *gateway;
|
|
route->lifetime = time_now + lifetime * USEC_PER_SEC;
|
|
|
|
r = route_configure(route, link, ndisc_netlink_handler);
|
|
if (r < 0) {
|
|
log_link_warning_errno(link, r, "Could not set default route: %m");
|
|
link_enter_failed(link);
|
|
return;
|
|
}
|
|
|
|
link->ndisc_messages ++;
|
|
}
|
|
|
|
static void ndisc_handler(sd_ndisc *nd, int event, void *userdata) {
|
|
Link *link = userdata;
|
|
int r;
|
|
|
|
assert(link);
|
|
|
|
if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
|
|
return;
|
|
|
|
switch (event) {
|
|
case SD_NDISC_EVENT_TIMEOUT:
|
|
dhcp6_request_address(link);
|
|
|
|
r = sd_dhcp6_client_start(link->dhcp6_client);
|
|
if (r < 0 && r != -EALREADY)
|
|
log_link_warning_errno(link, r, "Starting DHCPv6 client after NDisc timeout failed: %m");
|
|
break;
|
|
case SD_NDISC_EVENT_STOP:
|
|
break;
|
|
default:
|
|
log_link_warning(link, "IPv6 Neighbor Discovery unknown event: %d", event);
|
|
}
|
|
}
|
|
|
|
int ndisc_configure(Link *link) {
|
|
int r;
|
|
|
|
assert_return(link, -EINVAL);
|
|
|
|
r = sd_ndisc_new(&link->ndisc_router_discovery);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_ndisc_attach_event(link->ndisc_router_discovery, NULL, 0);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_ndisc_set_mac(link->ndisc_router_discovery, &link->mac);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_ndisc_set_index(link->ndisc_router_discovery, link->ifindex);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_ndisc_set_callback(link->ndisc_router_discovery,
|
|
ndisc_router_handler,
|
|
ndisc_prefix_onlink_handler,
|
|
ndisc_prefix_autonomous_handler,
|
|
ndisc_handler,
|
|
link);
|
|
|
|
return r;
|
|
}
|