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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
Copyright © 2014 Intel Corporation. All rights reserved.
***/
#include <netinet/icmp6.h>
#include <netinet/in.h>
#include "sd-ndisc.h"
#include "alloc-util.h"
#include "event-util.h"
#include "fd-util.h"
#include "icmp6-util.h"
#include "in-addr-util.h"
#include "memory-util.h"
#include "ndisc-internal.h"
#include "ndisc-router.h"
#include "network-common.h"
#include "random-util.h"
#include "socket-util.h"
#include "string-table.h"
#include "string-util.h"
#define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS)
static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = {
[SD_NDISC_EVENT_TIMEOUT] = "timeout",
[SD_NDISC_EVENT_ROUTER] = "router",
};
DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event_t);
static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event_t event, sd_ndisc_router *rt) {
assert(ndisc);
assert(event >= 0 && event < _SD_NDISC_EVENT_MAX);
if (!ndisc->callback)
return (void) log_ndisc(ndisc, "Received '%s' event.", ndisc_event_to_string(event));
log_ndisc(ndisc, "Invoking callback for '%s' event.", ndisc_event_to_string(event));
ndisc->callback(ndisc, event, rt, ndisc->userdata);
}
int sd_ndisc_set_callback(
sd_ndisc *nd,
sd_ndisc_callback_t callback,
void *userdata) {
assert_return(nd, -EINVAL);
nd->callback = callback;
nd->userdata = userdata;
return 0;
}
int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) {
assert_return(nd, -EINVAL);
assert_return(ifindex > 0, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
nd->ifindex = ifindex;
return 0;
}
int sd_ndisc_set_ifname(sd_ndisc *nd, const char *ifname) {
assert_return(nd, -EINVAL);
assert_return(ifname, -EINVAL);
if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
return -EINVAL;
return free_and_strdup(&nd->ifname, ifname);
}
int sd_ndisc_get_ifname(sd_ndisc *nd, const char **ret) {
int r;
assert_return(nd, -EINVAL);
r = get_ifname(nd->ifindex, &nd->ifname);
if (r < 0)
return r;
if (ret)
*ret = nd->ifname;
return 0;
}
int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) {
assert_return(nd, -EINVAL);
if (mac_addr)
nd->mac_addr = *mac_addr;
else
zero(nd->mac_addr);
return 0;
}
int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) {
int r;
assert_return(nd, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
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_ndisc_detach_event(sd_ndisc *nd) {
assert_return(nd, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
nd->event = sd_event_unref(nd->event);
return 0;
}
sd_event *sd_ndisc_get_event(sd_ndisc *nd) {
assert_return(nd, NULL);
return nd->event;
}
static void ndisc_reset(sd_ndisc *nd) {
assert(nd);
(void) event_source_disable(nd->timeout_event_source);
(void) event_source_disable(nd->timeout_no_ra);
nd->retransmit_time = 0;
nd->recv_event_source = sd_event_source_disable_unref(nd->recv_event_source);
nd->fd = safe_close(nd->fd);
}
static sd_ndisc *ndisc_free(sd_ndisc *nd) {
assert(nd);
ndisc_reset(nd);
sd_event_source_unref(nd->timeout_event_source);
sd_event_source_unref(nd->timeout_no_ra);
sd_ndisc_detach_event(nd);
free(nd->ifname);
return mfree(nd);
}
DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free);
int sd_ndisc_new(sd_ndisc **ret) {
_cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL;
assert_return(ret, -EINVAL);
nd = new(sd_ndisc, 1);
if (!nd)
return -ENOMEM;
*nd = (sd_ndisc) {
.n_ref = 1,
.fd = -1,
};
*ret = TAKE_PTR(nd);
return 0;
}
static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) {
int r;
assert(nd);
assert(rt);
r = ndisc_router_parse(nd, rt);
if (r < 0)
return r;
log_ndisc(nd, "Received Router Advertisement: flags %s preference %s lifetime %" PRIu16 " sec",
rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none",
rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium",
rt->lifetime);
ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
return 0;
}
static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
sd_ndisc *nd = ASSERT_PTR(userdata);
ssize_t buflen;
int r;
assert(s);
assert(nd->event);
buflen = next_datagram_size_fd(fd);
if (buflen < 0) {
if (ERRNO_IS_TRANSIENT(buflen) || ERRNO_IS_DISCONNECT(buflen))
return 0;
log_ndisc_errno(nd, buflen, "Failed to determine datagram size to read, ignoring: %m");
return 0;
}
rt = ndisc_router_new(buflen);
if (!rt)
return -ENOMEM;
r = icmp6_receive(fd, NDISC_ROUTER_RAW(rt), rt->raw_size, &rt->address, &rt->timestamp);
if (r < 0) {
if (ERRNO_IS_TRANSIENT(r) || ERRNO_IS_DISCONNECT(r))
return 0;
switch (r) {
case -EADDRNOTAVAIL:
log_ndisc(nd, "Received RA from non-link-local address %s. Ignoring.",
IN6_ADDR_TO_STRING(&rt->address));
break;
case -EMULTIHOP:
log_ndisc(nd, "Received RA with invalid hop limit. Ignoring.");
break;
case -EPFNOSUPPORT:
log_ndisc(nd, "Received invalid source address from ICMPv6 socket. Ignoring.");
break;
default:
log_ndisc_errno(nd, r, "Unexpected error while reading from ICMPv6, ignoring: %m");
break;
}
return 0;
}
(void) event_source_disable(nd->timeout_event_source);
(void) ndisc_handle_datagram(nd, rt);
return 0;
}
static usec_t ndisc_timeout_compute_random(usec_t val) {
/* compute a time that is random within ±10% of the given value */
return val - val / 10 +
(random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
}
static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
sd_ndisc *nd = ASSERT_PTR(userdata);
usec_t time_now;
int r;
assert(s);
assert(nd->event);
assert_se(sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now) >= 0);
if (!nd->retransmit_time)
nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL);
else {
if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2)
nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL);
else
nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time);
}
r = event_reset_time(nd->event, &nd->timeout_event_source,
CLOCK_BOOTTIME,
time_now + nd->retransmit_time, 10 * USEC_PER_MSEC,
ndisc_timeout, nd,
nd->event_priority, "ndisc-timeout-no-ra", true);
if (r < 0)
goto fail;
r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr);
if (r < 0)
log_ndisc_errno(nd, r, "Failed to send Router Solicitation, next solicitation in %s, ignoring: %m",
FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
else
log_ndisc(nd, "Sent Router Solicitation, next solicitation in %s",
FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
return 0;
fail:
(void) sd_ndisc_stop(nd);
return 0;
}
static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata) {
sd_ndisc *nd = ASSERT_PTR(userdata);
assert(s);
log_ndisc(nd, "No RA received before link confirmation timeout");
(void) event_source_disable(nd->timeout_no_ra);
ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL);
return 0;
}
int sd_ndisc_stop(sd_ndisc *nd) {
if (!nd)
return 0;
if (nd->fd < 0)
return 0;
log_ndisc(nd, "Stopping IPv6 Router Solicitation client");
ndisc_reset(nd);
return 1;
}
int sd_ndisc_start(sd_ndisc *nd) {
int r;
usec_t time_now;
assert_return(nd, -EINVAL);
assert_return(nd->event, -EINVAL);
assert_return(nd->ifindex > 0, -EINVAL);
if (nd->fd >= 0)
return 0;
assert(!nd->recv_event_source);
r = sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now);
if (r < 0)
goto fail;
nd->fd = icmp6_bind_router_solicitation(nd->ifindex);
if (nd->fd < 0)
return nd->fd;
r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd);
if (r < 0)
goto fail;
r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority);
if (r < 0)
goto fail;
(void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message");
r = event_reset_time(nd->event, &nd->timeout_event_source,
CLOCK_BOOTTIME,
time_now + USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */
ndisc_timeout, nd,
nd->event_priority, "ndisc-timeout", true);
if (r < 0)
goto fail;
r = event_reset_time(nd->event, &nd->timeout_no_ra,
CLOCK_BOOTTIME,
time_now + NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC,
ndisc_timeout_no_ra, nd,
nd->event_priority, "ndisc-timeout-no-ra", true);
if (r < 0)
goto fail;
log_ndisc(nd, "Started IPv6 Router Solicitation client");
return 1;
fail:
ndisc_reset(nd);
return r;
}
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