[thirdparty/systemd.git] / src / libsystemd-network / sd-ndisc.c

/* 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 "ether-addr-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-neighbor-internal.h"
#include "ndisc-redirect-internal.h"
#include "ndisc-router-internal.h"
#include "network-common.h"
#include "random-util.h"
#include "set.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",
        [SD_NDISC_EVENT_NEIGHBOR] = "neighbor",
        [SD_NDISC_EVENT_REDIRECT] = "redirect",
};

DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event_t);

static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event_t event, void *message) {
        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, message, ndisc->userdata);
}

int sd_ndisc_is_running(sd_ndisc *nd) {
        if (!nd)
                return false;

        return sd_event_source_get_enabled(nd->recv_event_source, NULL) > 0;
}

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(!sd_ndisc_is_running(nd), -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_link_local_address(sd_ndisc *nd, const struct in6_addr *addr) {
        assert_return(nd, -EINVAL);
        assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);

        if (addr)
                nd->link_local_addr = *addr;
        else
                zero(nd->link_local_addr);

        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(!sd_ndisc_is_running(nd), -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(!sd_ndisc_is_running(nd), -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 = -EBADF,
        };

        *ret = TAKE_PTR(nd);

        return 0;
}

static int ndisc_handle_router(sd_ndisc *nd, ICMP6Packet *packet) {
        _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
        int r;

        assert(nd);
        assert(packet);

        rt = ndisc_router_new(packet);
        if (!rt)
                return -ENOMEM;

        r = ndisc_router_parse(nd, rt);
        if (r < 0)
                return r;

        (void) event_source_disable(nd->timeout_event_source);
        (void) event_source_disable(nd->timeout_no_ra);

        if (DEBUG_LOGGING) {
                _cleanup_free_ char *s = NULL;
                struct in6_addr a;
                uint64_t flags;
                uint8_t pref;
                usec_t lifetime;

                r = sd_ndisc_router_get_sender_address(rt, &a);
                if (r < 0)
                        return r;

                r = sd_ndisc_router_get_flags(rt, &flags);
                if (r < 0)
                        return r;

                r = ndisc_router_flags_to_string(flags, &s);
                if (r < 0)
                        return r;

                r = sd_ndisc_router_get_preference(rt, &pref);
                if (r < 0)
                        return r;

                r = sd_ndisc_router_get_lifetime(rt, &lifetime);
                if (r < 0)
                        return r;

                log_ndisc(nd, "Received Router Advertisement from %s: flags=0x%0*"PRIx64"(%s), preference=%s, lifetime=%s",
                          IN6_ADDR_TO_STRING(&a),
                          flags & UINT64_C(0x00ffffffffffff00) ? 14 : 2, flags, /* suppress too many zeros if no extension */
                          s ?: "none",
                          ndisc_router_preference_to_string(pref),
                          FORMAT_TIMESPAN(lifetime, USEC_PER_SEC));
        }

        ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
        return 0;
}

static int ndisc_handle_neighbor(sd_ndisc *nd, ICMP6Packet *packet) {
        _cleanup_(sd_ndisc_neighbor_unrefp) sd_ndisc_neighbor *na = NULL;
        int r;

        assert(nd);
        assert(packet);

        na = ndisc_neighbor_new(packet);
        if (!na)
                return -ENOMEM;

        r = ndisc_neighbor_parse(nd, na);
        if (r < 0)
                return r;

        if (DEBUG_LOGGING) {
                struct in6_addr a;

                r = sd_ndisc_neighbor_get_sender_address(na, &a);
                if (r < 0)
                        return r;

                log_ndisc(nd, "Received Neighbor Advertisement from %s: Router=%s, Solicited=%s, Override=%s",
                          IN6_ADDR_TO_STRING(&a),
                          yes_no(sd_ndisc_neighbor_is_router(na) > 0),
                          yes_no(sd_ndisc_neighbor_is_solicited(na) > 0),
                          yes_no(sd_ndisc_neighbor_is_override(na) > 0));
        }

        ndisc_callback(nd, SD_NDISC_EVENT_NEIGHBOR, na);
        return 0;
}

static int ndisc_handle_redirect(sd_ndisc *nd, ICMP6Packet *packet) {
        _cleanup_(sd_ndisc_redirect_unrefp) sd_ndisc_redirect *rd = NULL;
        int r;

        assert(nd);
        assert(packet);

        rd = ndisc_redirect_new(packet);
        if (!rd)
                return -ENOMEM;

        r = ndisc_redirect_parse(nd, rd);
        if (r < 0)
                return r;

        if (DEBUG_LOGGING) {
                struct in6_addr sender, target, dest;

                r = sd_ndisc_redirect_get_sender_address(rd, &sender);
                if (r < 0)
                        return r;

                r = sd_ndisc_redirect_get_target_address(rd, &target);
                if (r < 0)
                        return r;

                r = sd_ndisc_redirect_get_destination_address(rd, &dest);
                if (r < 0)
                        return r;

                log_ndisc(nd, "Received Redirect message from %s: Target=%s, Destination=%s",
                          IN6_ADDR_TO_STRING(&sender),
                          IN6_ADDR_TO_STRING(&target),
                          IN6_ADDR_TO_STRING(&dest));
        }

        ndisc_callback(nd, SD_NDISC_EVENT_REDIRECT, rd);
        return 0;
}

static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
        _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
        sd_ndisc *nd = ASSERT_PTR(userdata);
        int r;

        assert(s);
        assert(nd->event);

        r = icmp6_packet_receive(fd, &packet);
        if (r < 0) {
                log_ndisc_errno(nd, r, "Failed to receive ICMPv6 packet, ignoring: %m");
                return 0;
        }

        /* The function icmp6_receive() accepts the null source address, but RFC 4861 Section 6.1.2 states
         * that hosts MUST discard messages with the null source address. */
        if (in6_addr_is_null(&packet->sender_address)) {
                log_ndisc(nd, "Received an ICMPv6 packet from null address, ignoring.");
                return 0;
        }

        if (in6_addr_equal(&packet->sender_address, &nd->link_local_addr)) {
                log_ndisc(nd, "Received an ICMPv6 packet sent by the same interface, ignoring.");
                return 0;
        }

        r = icmp6_packet_get_type(packet);
        if (r < 0) {
                log_ndisc_errno(nd, r, "Received an invalid ICMPv6 packet, ignoring: %m");
                return 0;
        }

        switch (r) {
        case ND_ROUTER_ADVERT:
                (void) ndisc_handle_router(nd, packet);
                break;

        case ND_NEIGHBOR_ADVERT:
                (void) ndisc_handle_neighbor(nd, packet);
                break;

        case ND_REDIRECT:
                (void) ndisc_handle_redirect(nd, packet);
                break;

        default:
                log_ndisc(nd, "Received an ICMPv6 packet with unexpected type %i, ignoring.", r);
        }

        return 0;
}

static int ndisc_send_router_solicitation(sd_ndisc *nd) {
        static const struct nd_router_solicit header = {
                .nd_rs_type = ND_ROUTER_SOLICIT,
        };

        _cleanup_set_free_ Set *options = NULL;
        int r;

        assert(nd);

        if (!ether_addr_is_null(&nd->mac_addr)) {
                r = ndisc_option_set_link_layer_address(&options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, &nd->mac_addr);
                if (r < 0)
                        return r;
        }

        return ndisc_send(nd->fd, &IN6_ADDR_ALL_ROUTERS_MULTICAST, &header.nd_rs_hdr, options, USEC_INFINITY);
}

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 = ndisc_send_router_solicitation(nd);
        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 (!sd_ndisc_is_running(nd))
                return 0;

        log_ndisc(nd, "Stopping IPv6 Router Solicitation client");

        ndisc_reset(nd);
        return 1;
}

static int ndisc_setup_recv_event(sd_ndisc *nd) {
        int r;

        assert(nd);
        assert(nd->event);
        assert(nd->ifindex > 0);

        _cleanup_close_ int fd = -EBADF;
        fd = icmp6_bind(nd->ifindex, /* is_router = */ false);
        if (fd < 0)
                return fd;

        _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
        r = sd_event_add_io(nd->event, &s, fd, EPOLLIN, ndisc_recv, nd);
        if (r < 0)
                return r;

        r = sd_event_source_set_priority(s, nd->event_priority);
        if (r < 0)
                return r;

        (void) sd_event_source_set_description(s, "ndisc-receive-router-message");

        nd->fd = TAKE_FD(fd);
        nd->recv_event_source = TAKE_PTR(s);
        return 1;
}

static int ndisc_setup_timer(sd_ndisc *nd) {
        int r;

        assert(nd);
        assert(nd->event);

        r = event_reset_time_relative(nd->event, &nd->timeout_event_source,
                                      CLOCK_BOOTTIME,
                                      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)
                return r;

        r = event_reset_time_relative(nd->event, &nd->timeout_no_ra,
                                      CLOCK_BOOTTIME,
                                      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)
                return r;

        return 0;
}

int sd_ndisc_start(sd_ndisc *nd) {
        int r;

        assert_return(nd, -EINVAL);
        assert_return(nd->event, -EINVAL);
        assert_return(nd->ifindex > 0, -EINVAL);

        if (sd_ndisc_is_running(nd))
                return 0;

        r = ndisc_setup_recv_event(nd);
        if (r < 0)
                goto fail;

        r = ndisc_setup_timer(nd);
        if (r < 0)
                goto fail;

        log_ndisc(nd, "Started IPv6 Router Solicitation client");
        return 1;

fail:
        ndisc_reset(nd);
        return r;
}
Commit	Line	Data
	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
	2	/***
	3	Copyright © 2014 Intel Corporation. All rights reserved.
	4	***/
	5
	6	#include <netinet/icmp6.h>
	7	#include <netinet/in.h>
	8
	9	#include "sd-ndisc.h"
	10
	11	#include "alloc-util.h"
	12	#include "ether-addr-util.h"
	13	#include "event-util.h"
	14	#include "fd-util.h"
	15	#include "icmp6-util.h"
	16	#include "in-addr-util.h"
	17	#include "memory-util.h"
	18	#include "ndisc-internal.h"
	19	#include "ndisc-neighbor-internal.h"
	20	#include "ndisc-redirect-internal.h"
	21	#include "ndisc-router-internal.h"
	22	#include "network-common.h"
	23	#include "random-util.h"
	24	#include "set.h"
	25	#include "socket-util.h"
	26	#include "string-table.h"
	27	#include "string-util.h"
	28
	29	#define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS)
	30
	31	static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = {
	32	[SD_NDISC_EVENT_TIMEOUT] = "timeout",
	33	[SD_NDISC_EVENT_ROUTER] = "router",
	34	[SD_NDISC_EVENT_NEIGHBOR] = "neighbor",
	35	[SD_NDISC_EVENT_REDIRECT] = "redirect",
	36	};
	37
	38	DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event_t);
	39
	40	static void ndisc_callback(sd_ndisc ndisc, sd_ndisc_event_t event, void message) {
	41	assert(ndisc);
	42	assert(event >= 0 && event < _SD_NDISC_EVENT_MAX);
	43
	44	if (!ndisc->callback)
	45	return (void) log_ndisc(ndisc, "Received '%s' event.", ndisc_event_to_string(event));
	46
	47	log_ndisc(ndisc, "Invoking callback for '%s' event.", ndisc_event_to_string(event));
	48	ndisc->callback(ndisc, event, message, ndisc->userdata);
	49	}
	50
	51	int sd_ndisc_is_running(sd_ndisc *nd) {
	52	if (!nd)
	53	return false;
	54
	55	return sd_event_source_get_enabled(nd->recv_event_source, NULL) > 0;
	56	}
	57
	58	int sd_ndisc_set_callback(
	59	sd_ndisc *nd,
	60	sd_ndisc_callback_t callback,
	61	void *userdata) {
	62
	63	assert_return(nd, -EINVAL);
	64
	65	nd->callback = callback;
	66	nd->userdata = userdata;
	67
	68	return 0;
	69	}
	70
	71	int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) {
	72	assert_return(nd, -EINVAL);
	73	assert_return(ifindex > 0, -EINVAL);
	74	assert_return(!sd_ndisc_is_running(nd), -EBUSY);
	75
	76	nd->ifindex = ifindex;
	77	return 0;
	78	}
	79
	80	int sd_ndisc_set_ifname(sd_ndisc nd, const char ifname) {
	81	assert_return(nd, -EINVAL);
	82	assert_return(ifname, -EINVAL);
	83
	84	if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
	85	return -EINVAL;
	86
	87	return free_and_strdup(&nd->ifname, ifname);
	88	}
	89
	90	int sd_ndisc_get_ifname(sd_ndisc nd, const char *ret) {
	91	int r;
	92
	93	assert_return(nd, -EINVAL);
	94
	95	r = get_ifname(nd->ifindex, &nd->ifname);
	96	if (r < 0)
	97	return r;
	98
	99	if (ret)
	100	*ret = nd->ifname;
	101
	102	return 0;
	103	}
	104
	105	int sd_ndisc_set_link_local_address(sd_ndisc nd, const struct in6_addr addr) {
	106	assert_return(nd, -EINVAL);
	107	assert_return(!addr \|\| in6_addr_is_link_local(addr), -EINVAL);
	108
	109	if (addr)
	110	nd->link_local_addr = *addr;
	111	else
	112	zero(nd->link_local_addr);
	113
	114	return 0;
	115	}
	116
	117	int sd_ndisc_set_mac(sd_ndisc nd, const struct ether_addr mac_addr) {
	118	assert_return(nd, -EINVAL);
	119
	120	if (mac_addr)
	121	nd->mac_addr = *mac_addr;
	122	else
	123	zero(nd->mac_addr);
	124
	125	return 0;
	126	}
	127
	128	int sd_ndisc_attach_event(sd_ndisc nd, sd_event event, int64_t priority) {
	129	int r;
	130
	131	assert_return(nd, -EINVAL);
	132	assert_return(!sd_ndisc_is_running(nd), -EBUSY);
	133	assert_return(!nd->event, -EBUSY);
	134
	135	if (event)
	136	nd->event = sd_event_ref(event);
	137	else {
	138	r = sd_event_default(&nd->event);
	139	if (r < 0)
	140	return 0;
	141	}
	142
	143	nd->event_priority = priority;
	144
	145	return 0;
	146	}
	147
	148	int sd_ndisc_detach_event(sd_ndisc *nd) {
	149
	150	assert_return(nd, -EINVAL);
	151	assert_return(!sd_ndisc_is_running(nd), -EBUSY);
	152
	153	nd->event = sd_event_unref(nd->event);
	154	return 0;
	155	}
	156
	157	sd_event sd_ndisc_get_event(sd_ndisc nd) {
	158	assert_return(nd, NULL);
	159
	160	return nd->event;
	161	}
	162
	163	static void ndisc_reset(sd_ndisc *nd) {
	164	assert(nd);
	165
	166	(void) event_source_disable(nd->timeout_event_source);
	167	(void) event_source_disable(nd->timeout_no_ra);
	168	nd->retransmit_time = 0;
	169	nd->recv_event_source = sd_event_source_disable_unref(nd->recv_event_source);
	170	nd->fd = safe_close(nd->fd);
	171	}
	172
	173	static sd_ndisc ndisc_free(sd_ndisc nd) {
	174	assert(nd);
	175
	176	ndisc_reset(nd);
	177
	178	sd_event_source_unref(nd->timeout_event_source);
	179	sd_event_source_unref(nd->timeout_no_ra);
	180	sd_ndisc_detach_event(nd);
	181
	182	free(nd->ifname);
	183	return mfree(nd);
	184	}
	185
	186	DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free);
	187
	188	int sd_ndisc_new(sd_ndisc **ret) {
	189	_cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL;
	190
	191	assert_return(ret, -EINVAL);
	192
	193	nd = new(sd_ndisc, 1);
	194	if (!nd)
	195	return -ENOMEM;
	196
	197	*nd = (sd_ndisc) {
	198	.n_ref = 1,
	199	.fd = -EBADF,
	200	};
	201
	202	*ret = TAKE_PTR(nd);
	203
	204	return 0;
	205	}
	206
	207	static int ndisc_handle_router(sd_ndisc nd, ICMP6Packet packet) {
	208	_cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
	209	int r;
	210
	211	assert(nd);
	212	assert(packet);
	213
	214	rt = ndisc_router_new(packet);
	215	if (!rt)
	216	return -ENOMEM;
	217
	218	r = ndisc_router_parse(nd, rt);
	219	if (r < 0)
	220	return r;
	221
	222	(void) event_source_disable(nd->timeout_event_source);
	223	(void) event_source_disable(nd->timeout_no_ra);
	224
	225	if (DEBUG_LOGGING) {
	226	_cleanup_free_ char *s = NULL;
	227	struct in6_addr a;
	228	uint64_t flags;
	229	uint8_t pref;
	230	usec_t lifetime;
	231
	232	r = sd_ndisc_router_get_sender_address(rt, &a);
	233	if (r < 0)
	234	return r;
	235
	236	r = sd_ndisc_router_get_flags(rt, &flags);
	237	if (r < 0)
	238	return r;
	239
	240	r = ndisc_router_flags_to_string(flags, &s);
	241	if (r < 0)
	242	return r;
	243
	244	r = sd_ndisc_router_get_preference(rt, &pref);
	245	if (r < 0)
	246	return r;
	247
	248	r = sd_ndisc_router_get_lifetime(rt, &lifetime);
	249	if (r < 0)
	250	return r;
	251
	252	log_ndisc(nd, "Received Router Advertisement from %s: flags=0x%0*"PRIx64"(%s), preference=%s, lifetime=%s",
	253	IN6_ADDR_TO_STRING(&a),
	254	flags & UINT64_C(0x00ffffffffffff00) ? 14 : 2, flags, /* suppress too many zeros if no extension */
	255	s ?: "none",
	256	ndisc_router_preference_to_string(pref),
	257	FORMAT_TIMESPAN(lifetime, USEC_PER_SEC));
	258	}
	259
	260	ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
	261	return 0;
	262	}
	263
	264	static int ndisc_handle_neighbor(sd_ndisc nd, ICMP6Packet packet) {
	265	_cleanup_(sd_ndisc_neighbor_unrefp) sd_ndisc_neighbor *na = NULL;
	266	int r;
	267
	268	assert(nd);
	269	assert(packet);
	270
	271	na = ndisc_neighbor_new(packet);
	272	if (!na)
	273	return -ENOMEM;
	274
	275	r = ndisc_neighbor_parse(nd, na);
	276	if (r < 0)
	277	return r;
	278
	279	if (DEBUG_LOGGING) {
	280	struct in6_addr a;
	281
	282	r = sd_ndisc_neighbor_get_sender_address(na, &a);
	283	if (r < 0)
	284	return r;
	285
	286	log_ndisc(nd, "Received Neighbor Advertisement from %s: Router=%s, Solicited=%s, Override=%s",
	287	IN6_ADDR_TO_STRING(&a),
	288	yes_no(sd_ndisc_neighbor_is_router(na) > 0),
	289	yes_no(sd_ndisc_neighbor_is_solicited(na) > 0),
	290	yes_no(sd_ndisc_neighbor_is_override(na) > 0));
	291	}
	292
	293	ndisc_callback(nd, SD_NDISC_EVENT_NEIGHBOR, na);
	294	return 0;
	295	}
	296
	297	static int ndisc_handle_redirect(sd_ndisc nd, ICMP6Packet packet) {
	298	_cleanup_(sd_ndisc_redirect_unrefp) sd_ndisc_redirect *rd = NULL;
	299	int r;
	300
	301	assert(nd);
	302	assert(packet);
	303
	304	rd = ndisc_redirect_new(packet);
	305	if (!rd)
	306	return -ENOMEM;
	307
	308	r = ndisc_redirect_parse(nd, rd);
	309	if (r < 0)
	310	return r;
	311
	312	if (DEBUG_LOGGING) {
	313	struct in6_addr sender, target, dest;
	314
	315	r = sd_ndisc_redirect_get_sender_address(rd, &sender);
	316	if (r < 0)
	317	return r;
	318
	319	r = sd_ndisc_redirect_get_target_address(rd, &target);
	320	if (r < 0)
	321	return r;
	322
	323	r = sd_ndisc_redirect_get_destination_address(rd, &dest);
	324	if (r < 0)
	325	return r;
	326
	327	log_ndisc(nd, "Received Redirect message from %s: Target=%s, Destination=%s",
	328	IN6_ADDR_TO_STRING(&sender),
	329	IN6_ADDR_TO_STRING(&target),
	330	IN6_ADDR_TO_STRING(&dest));
	331	}
	332
	333	ndisc_callback(nd, SD_NDISC_EVENT_REDIRECT, rd);
	334	return 0;
	335	}
	336
	337	static int ndisc_recv(sd_event_source s, int fd, uint32_t revents, void userdata) {
	338	_cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
	339	sd_ndisc *nd = ASSERT_PTR(userdata);
	340	int r;
	341
	342	assert(s);
	343	assert(nd->event);
	344
	345	r = icmp6_packet_receive(fd, &packet);
	346	if (r < 0) {
	347	log_ndisc_errno(nd, r, "Failed to receive ICMPv6 packet, ignoring: %m");
	348	return 0;
	349	}
	350
	351	/* The function icmp6_receive() accepts the null source address, but RFC 4861 Section 6.1.2 states
	352	* that hosts MUST discard messages with the null source address. */
	353	if (in6_addr_is_null(&packet->sender_address)) {
	354	log_ndisc(nd, "Received an ICMPv6 packet from null address, ignoring.");
	355	return 0;
	356	}
	357
	358	if (in6_addr_equal(&packet->sender_address, &nd->link_local_addr)) {
	359	log_ndisc(nd, "Received an ICMPv6 packet sent by the same interface, ignoring.");
	360	return 0;
	361	}
	362
	363	r = icmp6_packet_get_type(packet);
	364	if (r < 0) {
	365	log_ndisc_errno(nd, r, "Received an invalid ICMPv6 packet, ignoring: %m");
	366	return 0;
	367	}
	368
	369	switch (r) {
	370	case ND_ROUTER_ADVERT:
	371	(void) ndisc_handle_router(nd, packet);
	372	break;
	373
	374	case ND_NEIGHBOR_ADVERT:
	375	(void) ndisc_handle_neighbor(nd, packet);
	376	break;
	377
	378	case ND_REDIRECT:
	379	(void) ndisc_handle_redirect(nd, packet);
	380	break;
	381
	382	default:
	383	log_ndisc(nd, "Received an ICMPv6 packet with unexpected type %i, ignoring.", r);
	384	}
	385
	386	return 0;
	387	}
	388
	389	static int ndisc_send_router_solicitation(sd_ndisc *nd) {
	390	static const struct nd_router_solicit header = {
	391	.nd_rs_type = ND_ROUTER_SOLICIT,
	392	};
	393
	394	_cleanup_set_free_ Set *options = NULL;
	395	int r;
	396
	397	assert(nd);
	398
	399	if (!ether_addr_is_null(&nd->mac_addr)) {
	400	r = ndisc_option_set_link_layer_address(&options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, &nd->mac_addr);
	401	if (r < 0)
	402	return r;
	403	}
	404
	405	return ndisc_send(nd->fd, &IN6_ADDR_ALL_ROUTERS_MULTICAST, &header.nd_rs_hdr, options, USEC_INFINITY);
	406	}
	407
	408	static usec_t ndisc_timeout_compute_random(usec_t val) {
	409	/* compute a time that is random within ±10% of the given value */
	410	return val - val / 10 +
	411	(random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
	412	}
	413
	414	static int ndisc_timeout(sd_event_source s, uint64_t usec, void userdata) {
	415	sd_ndisc *nd = ASSERT_PTR(userdata);
	416	usec_t time_now;
	417	int r;
	418
	419	assert(s);
	420	assert(nd->event);
	421
	422	assert_se(sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now) >= 0);
	423
	424	if (!nd->retransmit_time)
	425	nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL);
	426	else {
	427	if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2)
	428	nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL);
	429	else
	430	nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time);
	431	}
	432
	433	r = event_reset_time(nd->event, &nd->timeout_event_source,
	434	CLOCK_BOOTTIME,
	435	time_now + nd->retransmit_time, 10 * USEC_PER_MSEC,
	436	ndisc_timeout, nd,
	437	nd->event_priority, "ndisc-timeout-no-ra", true);
	438	if (r < 0)
	439	goto fail;
	440
	441	r = ndisc_send_router_solicitation(nd);
	442	if (r < 0)
	443	log_ndisc_errno(nd, r, "Failed to send Router Solicitation, next solicitation in %s, ignoring: %m",
	444	FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
	445	else
	446	log_ndisc(nd, "Sent Router Solicitation, next solicitation in %s",
	447	FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
	448
	449	return 0;
	450
	451	fail:
	452	(void) sd_ndisc_stop(nd);
	453	return 0;
	454	}
	455
	456	static int ndisc_timeout_no_ra(sd_event_source s, uint64_t usec, void userdata) {
	457	sd_ndisc *nd = ASSERT_PTR(userdata);
	458
	459	assert(s);
	460
	461	log_ndisc(nd, "No RA received before link confirmation timeout");
	462
	463	(void) event_source_disable(nd->timeout_no_ra);
	464	ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL);
	465
	466	return 0;
	467	}
	468
	469	int sd_ndisc_stop(sd_ndisc *nd) {
	470	if (!nd)
	471	return 0;
	472
	473	if (!sd_ndisc_is_running(nd))
	474	return 0;
	475
	476	log_ndisc(nd, "Stopping IPv6 Router Solicitation client");
	477
	478	ndisc_reset(nd);
	479	return 1;
	480	}
	481
	482	static int ndisc_setup_recv_event(sd_ndisc *nd) {
	483	int r;
	484
	485	assert(nd);
	486	assert(nd->event);
	487	assert(nd->ifindex > 0);
	488
	489	_cleanup_close_ int fd = -EBADF;
	490	fd = icmp6_bind(nd->ifindex, /* is_router = */ false);
	491	if (fd < 0)
	492	return fd;
	493
	494	_cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
	495	r = sd_event_add_io(nd->event, &s, fd, EPOLLIN, ndisc_recv, nd);
	496	if (r < 0)
	497	return r;
	498
	499	r = sd_event_source_set_priority(s, nd->event_priority);
	500	if (r < 0)
	501	return r;
	502
	503	(void) sd_event_source_set_description(s, "ndisc-receive-router-message");
	504
	505	nd->fd = TAKE_FD(fd);
	506	nd->recv_event_source = TAKE_PTR(s);
	507	return 1;
	508	}
	509
	510	static int ndisc_setup_timer(sd_ndisc *nd) {
	511	int r;
	512
	513	assert(nd);
	514	assert(nd->event);
	515
	516	r = event_reset_time_relative(nd->event, &nd->timeout_event_source,
	517	CLOCK_BOOTTIME,
	518	USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */
	519	ndisc_timeout, nd,
	520	nd->event_priority, "ndisc-timeout", true);
	521	if (r < 0)
	522	return r;
	523
	524	r = event_reset_time_relative(nd->event, &nd->timeout_no_ra,
	525	CLOCK_BOOTTIME,
	526	NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC,
	527	ndisc_timeout_no_ra, nd,
	528	nd->event_priority, "ndisc-timeout-no-ra", true);
	529	if (r < 0)
	530	return r;
	531
	532	return 0;
	533	}
	534
	535	int sd_ndisc_start(sd_ndisc *nd) {
	536	int r;
	537
	538	assert_return(nd, -EINVAL);
	539	assert_return(nd->event, -EINVAL);
	540	assert_return(nd->ifindex > 0, -EINVAL);
	541
	542	if (sd_ndisc_is_running(nd))
	543	return 0;
	544
	545	r = ndisc_setup_recv_event(nd);
	546	if (r < 0)
	547	goto fail;
	548
	549	r = ndisc_setup_timer(nd);
	550	if (r < 0)
	551	goto fail;
	552
	553	log_ndisc(nd, "Started IPv6 Router Solicitation client");
	554	return 1;
	555
	556	fail:
	557	ndisc_reset(nd);
	558	return r;
	559	}