sd-icmp6-nd.c revision 06b643e7f5a3b79005dd57497897ab7255fe3659
/***
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/icmp6.h>
#include <string.h>
#include <stdbool.h>
#include <netinet/in.h>
#include "socket-util.h"
#include "refcnt.h"
#include "async.h"
#include "dhcp6-internal.h"
#include "sd-icmp6-nd.h"
#define ICMP6_ROUTER_SOLICITATION_INTERVAL 4 * USEC_PER_SEC
#define ICMP6_MAX_ROUTER_SOLICITATIONS 3
enum icmp6_nd_state {
ICMP6_NEIGHBOR_DISCOVERY_IDLE = 0,
ICMP6_ROUTER_SOLICITATION_SENT = 10,
ICMP6_ROUTER_ADVERTISMENT_LISTEN = 11,
};
struct sd_icmp6_nd {
RefCount n_ref;
enum icmp6_nd_state state;
sd_event *event;
int event_priority;
int index;
struct ether_addr mac_addr;
int fd;
sd_event_source *recv;
sd_event_source *timeout;
int nd_sent;
sd_icmp6_nd_callback_t callback;
void *userdata;
};
#define log_icmp6_nd(p, fmt, ...) log_meta(LOG_DEBUG, __FILE__, __LINE__, __func__, "ICMPv6 CLIENT: " fmt, ##__VA_ARGS__)
static void icmp6_nd_notify(sd_icmp6_nd *nd, int event)
{
if (nd->callback)
nd->callback(nd, event, nd->userdata);
}
int sd_icmp6_nd_set_callback(sd_icmp6_nd *nd, sd_icmp6_nd_callback_t callback,
void *userdata) {
assert(nd);
nd->callback = callback;
nd->userdata = userdata;
return 0;
}
int sd_icmp6_nd_set_index(sd_icmp6_nd *nd, int interface_index) {
assert(nd);
assert(interface_index >= -1);
nd->index = interface_index;
return 0;
}
int sd_icmp6_nd_set_mac(sd_icmp6_nd *nd, const struct ether_addr *mac_addr) {
assert(nd);
if (mac_addr)
memcpy(&nd->mac_addr, mac_addr, sizeof(nd->mac_addr));
else
memset(&nd->mac_addr, 0x00, sizeof(nd->mac_addr));
return 0;
}
int sd_icmp6_nd_attach_event(sd_icmp6_nd *nd, sd_event *event, int priority) {
int r;
assert_return(nd, -EINVAL);
assert_return(!nd->event, -EBUSY);
if (event)
nd->event = sd_event_ref(event);
else {
r = sd_event_default(&nd->event);
if (r < 0)
return 0;
}
nd->event_priority = priority;
return 0;
}
int sd_icmp6_nd_detach_event(sd_icmp6_nd *nd) {
assert_return(nd, -EINVAL);
nd->event = sd_event_unref(nd->event);
return 0;
}
sd_event *sd_icmp6_nd_get_event(sd_icmp6_nd *nd) {
assert(nd);
return nd->event;
}
sd_icmp6_nd *sd_icmp6_nd_ref(sd_icmp6_nd *nd) {
assert (nd);
assert_se(REFCNT_INC(nd->n_ref) >= 2);
return nd;
}
static int icmp6_nd_init(sd_icmp6_nd *nd) {
assert(nd);
nd->recv = sd_event_source_unref(nd->recv);
nd->fd = asynchronous_close(nd->fd);
nd->timeout = sd_event_source_unref(nd->timeout);
return 0;
}
sd_icmp6_nd *sd_icmp6_nd_unref(sd_icmp6_nd *nd) {
if (nd && REFCNT_DEC(nd->n_ref) <= 0) {
icmp6_nd_init(nd);
sd_icmp6_nd_detach_event(nd);
free(nd);
}
return NULL;
}
DEFINE_TRIVIAL_CLEANUP_FUNC(sd_icmp6_nd*, sd_icmp6_nd_unref);
#define _cleanup_sd_icmp6_nd_free_ _cleanup_(sd_icmp6_nd_unrefp)
int sd_icmp6_nd_new(sd_icmp6_nd **ret) {
_cleanup_sd_icmp6_nd_free_ sd_icmp6_nd *nd = NULL;
assert(ret);
nd = new0(sd_icmp6_nd, 1);
if (!nd)
return -ENOMEM;
nd->n_ref = REFCNT_INIT;
nd->index = -1;
nd->fd = -1;
*ret = nd;
nd = NULL;
return 0;
}
static int icmp6_router_advertisment_recv(sd_event_source *s, int fd,
uint32_t revents, void *userdata)
{
sd_icmp6_nd *nd = userdata;
ssize_t len;
struct nd_router_advert ra;
int event = ICMP6_EVENT_ROUTER_ADVERTISMENT_NONE;
assert(s);
assert(nd);
assert(nd->event);
/* only interested in Managed/Other flag */
len = read(fd, &ra, sizeof(ra));
if ((size_t)len < sizeof(ra))
return 0;
if (ra.nd_ra_type != ND_ROUTER_ADVERT)
return 0;
if (ra.nd_ra_code != 0)
return 0;
nd->timeout = sd_event_source_unref(nd->timeout);
nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
if (ra.nd_ra_flags_reserved & ND_RA_FLAG_OTHER )
event = ICMP6_EVENT_ROUTER_ADVERTISMENT_OTHER;
if (ra.nd_ra_flags_reserved & ND_RA_FLAG_MANAGED)
event = ICMP6_EVENT_ROUTER_ADVERTISMENT_MANAGED;
log_icmp6_nd(nd, "Received Router Advertisement flags %s/%s",
(ra.nd_ra_flags_reserved & ND_RA_FLAG_MANAGED)? "MANAGED":
"none",
(ra.nd_ra_flags_reserved & ND_RA_FLAG_OTHER)? "OTHER":
"none");
icmp6_nd_notify(nd, event);
return 0;
}
static int icmp6_router_solicitation_timeout(sd_event_source *s, uint64_t usec,
void *userdata)
{
sd_icmp6_nd *nd = userdata;
uint64_t time_now, next_timeout;
struct ether_addr unset = { };
struct ether_addr *addr = NULL;
int r;
assert(s);
assert(nd);
assert(nd->event);
nd->timeout = sd_event_source_unref(nd->timeout);
if (nd->nd_sent >= ICMP6_MAX_ROUTER_SOLICITATIONS) {
icmp6_nd_notify(nd, ICMP6_EVENT_ROUTER_ADVERTISMENT_TIMEOUT);
nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
} else {
if (memcmp(&nd->mac_addr, &unset, sizeof(struct ether_addr)))
addr = &nd->mac_addr;
r = dhcp_network_icmp6_send_router_solicitation(nd->fd, addr);
if (r < 0)
log_icmp6_nd(nd, "Error sending Router Solicitation");
else {
nd->state = ICMP6_ROUTER_SOLICITATION_SENT;
log_icmp6_nd(nd, "Sent Router Solicitation");
}
nd->nd_sent++;
r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
next_timeout = time_now + ICMP6_ROUTER_SOLICITATION_INTERVAL;
r = sd_event_add_time(nd->event, &nd->timeout, clock_boottime_or_monotonic(),
next_timeout, 0,
icmp6_router_solicitation_timeout, nd);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
r = sd_event_source_set_priority(nd->timeout,
nd->event_priority);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
r = sd_event_source_set_name(nd->timeout, "icmp6-timeout");
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
}
return 0;
}
int sd_icmp6_nd_stop(sd_icmp6_nd *nd) {
assert_return(nd, -EINVAL);
assert_return(nd->event, -EINVAL);
log_icmp6_nd(client, "Stop ICMPv6");
icmp6_nd_init(nd);
nd->state = ICMP6_NEIGHBOR_DISCOVERY_IDLE;
return 0;
}
int sd_icmp6_router_solicitation_start(sd_icmp6_nd *nd) {
int r;
assert(nd);
assert(nd->event);
if (nd->state != ICMP6_NEIGHBOR_DISCOVERY_IDLE)
return -EINVAL;
if (nd->index < 1)
return -EINVAL;
r = dhcp_network_icmp6_bind_router_solicitation(nd->index);
if (r < 0)
return r;
nd->fd = r;
r = sd_event_add_io(nd->event, &nd->recv, nd->fd, EPOLLIN,
icmp6_router_advertisment_recv, nd);
if (r < 0)
goto error;
r = sd_event_source_set_priority(nd->recv, nd->event_priority);
if (r < 0)
goto error;
r = sd_event_source_set_name(nd->recv, "icmp6-receive-message");
if (r < 0)
goto error;
r = sd_event_add_time(nd->event, &nd->timeout, clock_boottime_or_monotonic(),
0, 0, icmp6_router_solicitation_timeout, nd);
if (r < 0)
goto error;
r = sd_event_source_set_priority(nd->timeout, nd->event_priority);
if (r < 0)
goto error;
r = sd_event_source_set_name(nd->timeout, "icmp6-timeout");
error:
if (r < 0)
icmp6_nd_init(nd);
else
log_icmp6_nd(client, "Start Router Solicitation");
return r;
}