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bbb863a008ec29ffd7da0fab518f841f20664fd7
systemd/src/libsystemd-network/sd-radv.c
T
Chris Mason 3f0aa5852e libsystemd-network: propagate sd_event_default() failure 
Four *_attach_event helpers swallow sd_event_default() failures and
return success while leaving obj->event NULL:

    sd_dhcp_client_attach_event   (sd-dhcp-client.c)
    sd_dhcp6_client_attach_event  (sd-dhcp6-client.c)
    sd_ndisc_attach_event         (sd-ndisc.c)
    sd_radv_attach_event          (sd-radv.c)

Each contains the same copy-pasted typo in the NULL-event branch:

    r = sd_event_default(&obj->event);
    if (r < 0)
            return 0;          /* swallows -ENOMEM / -ECHILD */

The caller is told the attach succeeded, but obj->event is still
NULL. A subsequent *_start() then trips assert_return(obj->event,
-EINVAL) and returns a spurious -EINVAL (or aborts on assert-abort
builds), and any consumer of *_get_event() dereferences NULL.

The sibling helper sd_dhcp_server_attach_event already uses the
correct pattern:

    r = sd_event_default(&server->event);
    if (r < 0)
            return r;

Fix by returning r instead of 0 at each of the four sites so the
sd_event_default() errno is propagated to the caller and ownership
stays with the caller.

Assisted-by: kres (claude-opus-4-7)
Signed-off-by: Chris Mason <clm@meta.com>
2026-05-22 22:20:03 +02:00

736 lines
22 KiB
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
Copyright © 2017 Intel Corporation. All rights reserved.
***/
#include <linux/ipv6.h>
#include <netinet/icmp6.h>
#include <netinet/in.h>
#include "sd-ndisc-protocol.h"
#include "sd-ndisc-router-solicit.h"
#include "sd-radv.h"
#include "alloc-util.h"
#include "event-util.h"
#include "fd-util.h"
#include "icmp6-packet.h"
#include "icmp6-util.h"
#include "in-addr-util.h"
#include "memory-util.h"
#include "ndisc-option.h"
#include "ndisc-router-solicit-internal.h"
#include "network-common.h"
#include "radv-internal.h"
#include "random-util.h"
#include "set.h"
#include "socket-util.h"
#include "string-util.h"
int sd_radv_new(sd_radv **ret) {
_cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
assert_return(ret, -EINVAL);
ra = new(sd_radv, 1);
if (!ra)
return -ENOMEM;
*ra = (sd_radv) {
.n_ref = 1,
.fd = -EBADF,
.lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
};
*ret = TAKE_PTR(ra);
return 0;
}
int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
int r;
assert_return(ra, -EINVAL);
assert_return(!ra->event, -EBUSY);
if (event)
ra->event = sd_event_ref(event);
else {
r = sd_event_default(&ra->event);
if (r < 0)
return r;
}
ra->event_priority = priority;
return 0;
}
int sd_radv_detach_event(sd_radv *ra) {
assert_return(ra, -EINVAL);
ra->event = sd_event_unref(ra->event);
return 0;
}
sd_event *sd_radv_get_event(sd_radv *ra) {
assert_return(ra, NULL);
return ra->event;
}
int sd_radv_is_running(sd_radv *ra) {
if (!ra)
return false;
return ra->state != RADV_STATE_IDLE;
}
static void radv_reset(sd_radv *ra) {
assert(ra);
(void) event_source_disable(ra->timeout_event_source);
ra->recv_event_source = sd_event_source_disable_unref(ra->recv_event_source);
ra->ra_sent = 0;
}
static sd_radv *radv_free(sd_radv *ra) {
if (!ra)
return NULL;
radv_reset(ra);
sd_event_source_unref(ra->timeout_event_source);
sd_radv_detach_event(ra);
ra->fd = safe_close(ra->fd);
free(ra->ifname);
set_free(ra->options);
return mfree(ra);
}
DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
static bool router_lifetime_is_valid(usec_t lifetime_usec) {
assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
return lifetime_usec == 0 ||
(lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
}
static int radv_send_router_on_stop(sd_radv *ra) {
static const struct nd_router_advert adv = {
.nd_ra_type = ND_ROUTER_ADVERT,
};
_cleanup_set_free_ Set *options = NULL;
struct ether_addr mac_addr;
usec_t time_now;
int r;
assert(ra);
r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
if (r < 0)
return r;
/* On stop, we only send source link-layer address option. */
if (ndisc_option_get_mac(ra->options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, &mac_addr) >= 0) {
r = ndisc_option_set_link_layer_address(&options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, &mac_addr);
if (r < 0)
return r;
}
return ndisc_send(ra->fd, &IN6_ADDR_ALL_NODES_MULTICAST, &adv.nd_ra_hdr, options, time_now);
}
static int radv_send_router(sd_radv *ra, const struct in6_addr *dst) {
assert(ra);
struct nd_router_advert adv = {
.nd_ra_type = ND_ROUTER_ADVERT,
.nd_ra_router_lifetime = usec_to_be16_sec(ra->lifetime_usec),
.nd_ra_reachable = usec_to_be32_msec(ra->reachable_usec),
.nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec),
};
usec_t time_now;
int r;
r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
if (r < 0)
return r;
/* The nd_ra_curhoplimit and nd_ra_flags_reserved fields cannot specified with nd_ra_router_lifetime
* simultaneously in the structured initializer in the above. */
adv.nd_ra_curhoplimit = ra->hop_limit;
/* RFC 4191, Section 2.2,
* "...If the Router Lifetime is zero, the preference value MUST be set to (00) by the sender..." */
adv.nd_ra_flags_reserved = ra->flags | (ra->lifetime_usec > 0 ? (ra->preference << 3) : 0);
return ndisc_send(ra->fd,
(dst && in6_addr_is_set(dst)) ? dst : &IN6_ADDR_ALL_NODES_MULTICAST,
&adv.nd_ra_hdr, ra->options, time_now);
}
static int radv_process_packet(sd_radv *ra, ICMP6Packet *packet) {
int r;
assert(ra);
assert(packet);
if (icmp6_packet_get_type(packet) != ND_ROUTER_SOLICIT)
return log_radv_errno(ra, SYNTHETIC_ERRNO(EBADMSG), "Received ICMP6 packet with unexpected type, ignoring.");
_cleanup_(sd_ndisc_router_solicit_unrefp) sd_ndisc_router_solicit *rs = NULL;
rs = ndisc_router_solicit_new(packet);
if (!rs)
return log_oom_debug();
r = ndisc_router_solicit_parse(ra, rs);
if (r < 0)
return r;
struct in6_addr src;
r = sd_ndisc_router_solicit_get_sender_address(rs, &src);
if (r == -ENODATA) /* null address is allowed */
return sd_radv_send(ra); /* When an unsolicited RA, we need to also update timer. */
if (r < 0)
return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
if (in6_addr_equal(&src, &ra->ipv6ll))
/* This should be definitely caused by a misconfiguration. If we send RA to ourself, the
* kernel complains about that. Let's ignore the packet. */
return log_radv_errno(ra, SYNTHETIC_ERRNO(EADDRINUSE), "Received RS from the same interface, ignoring.");
r = radv_send_router(ra, &src);
if (r < 0)
return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
return 0;
}
static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
sd_radv *ra = ASSERT_PTR(userdata);
int r;
assert(fd >= 0);
r = icmp6_packet_receive(fd, &packet);
if (r < 0) {
log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
return 0;
}
if (packet->ifindex != ra->ifindex) {
log_radv(ra, "Received an ICMPv6 packet on interface %i, expected %i, ignoring.",
packet->ifindex, ra->ifindex);
return 0;
}
(void) radv_process_packet(ra, packet);
return 0;
}
static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
sd_radv *ra = ASSERT_PTR(userdata);
if (sd_radv_send(ra) < 0)
(void) sd_radv_stop(ra);
return 0;
}
int sd_radv_send(sd_radv *ra) {
usec_t min_timeout, max_timeout, time_now, timeout;
int r;
assert_return(ra, -EINVAL);
assert_return(ra->event, -EINVAL);
assert_return(sd_radv_is_running(ra), -EINVAL);
assert(router_lifetime_is_valid(ra->lifetime_usec));
r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
if (r < 0)
return r;
r = radv_send_router(ra, NULL);
if (r < 0)
/* Do not treat transient send failures (e.g. ENOBUFS while a bond is still selecting an
* aggregator after a carrier flap, or ENETDOWN/EADDRNOTAVAIL during a short link bounce) as
* fatal: log and reschedule so we try again instead of stopping the RA engine for good.
* Solicited RAs already behave this way, see radv_process_packet(). */
log_radv_errno(ra, r, "Unable to send Router Advertisement, will retry later: %m");
else
ra->ra_sent++;
/* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
if (ra->ra_sent <= RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
else
max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
/* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
* so lower the interval here */
if (ra->lifetime_usec > 0)
max_timeout = MIN(max_timeout, ra->lifetime_usec);
if (max_timeout >= 9 * USEC_PER_SEC)
min_timeout = max_timeout / 3;
else
min_timeout = max_timeout * 3 / 4;
/* RFC 4861, Section 6.2.1.
* MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
* MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
assert(min_timeout <= max_timeout * 3 / 4);
timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
if (r >= 0)
log_radv(ra, "Sent unsolicited Router Advertisement. Next advertisement will be in %s.",
FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
else
log_radv(ra, "Next Router Advertisement attempt in %s.",
FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
return event_reset_time(
ra->event, &ra->timeout_event_source,
CLOCK_BOOTTIME,
usec_add(time_now, timeout), MSEC_PER_SEC,
radv_timeout, ra,
ra->event_priority, "radv-timeout", true);
}
int sd_radv_stop(sd_radv *ra) {
int r;
if (!sd_radv_is_running(ra))
return 0; /* Already stopped. */
log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
/* RFC 4861, Section 6.2.5:
* the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
* multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
r = radv_send_router_on_stop(ra);
if (r < 0)
log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
radv_reset(ra);
ra->fd = safe_close(ra->fd);
ra->state = RADV_STATE_IDLE;
return 0;
}
static int radv_setup_recv_event(sd_radv *ra) {
int r;
assert(ra);
assert(ra->event);
assert(ra->ifindex > 0);
_cleanup_close_ int fd = -EBADF;
fd = icmp6_bind(ra->ifindex, /* is_router= */ true);
if (fd < 0)
return fd;
_cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
if (r < 0)
return r;
r = sd_event_source_set_priority(s, ra->event_priority);
if (r < 0)
return r;
(void) sd_event_source_set_description(s, "radv-receive-message");
ra->fd = TAKE_FD(fd);
ra->recv_event_source = TAKE_PTR(s);
return 0;
}
int sd_radv_start(sd_radv *ra) {
int r;
assert_return(ra, -EINVAL);
assert_return(ra->event, -EINVAL);
assert_return(ra->ifindex > 0, -EINVAL);
if (sd_radv_is_running(ra))
return 0; /* Already started. */
r = radv_setup_recv_event(ra);
if (r < 0)
goto fail;
r = event_reset_time(ra->event, &ra->timeout_event_source,
CLOCK_BOOTTIME,
0, 0,
radv_timeout, ra,
ra->event_priority, "radv-timeout", true);
if (r < 0)
goto fail;
ra->state = RADV_STATE_ADVERTISING;
log_radv(ra, "Started IPv6 Router Advertisement daemon");
return 0;
fail:
radv_reset(ra);
return r;
}
int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
assert_return(ra, -EINVAL);
assert_return(!sd_radv_is_running(ra), -EBUSY);
assert_return(ifindex > 0, -EINVAL);
ra->ifindex = ifindex;
return 0;
}
int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
assert_return(ra, -EINVAL);
assert_return(ifname, -EINVAL);
if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
return -EINVAL;
return free_and_strdup(&ra->ifname, ifname);
}
int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
int r;
assert_return(ra, -EINVAL);
r = get_ifname(ra->ifindex, &ra->ifname);
if (r < 0)
return r;
if (ret)
*ret = ra->ifname;
return 0;
}
int sd_radv_set_link_local_address(sd_radv *ra, const struct in6_addr *addr) {
assert_return(ra, -EINVAL);
assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);
if (addr)
ra->ipv6ll = *addr;
else
zero(ra->ipv6ll);
return 0;
}
/* Managing RA header. */
int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
assert_return(ra, -EINVAL);
ra->hop_limit = hop_limit;
return 0;
}
int sd_radv_set_reachable_time(sd_radv *ra, uint64_t usec) {
assert_return(ra, -EINVAL);
ra->reachable_usec = usec;
return 0;
}
int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
assert_return(ra, -EINVAL);
ra->retransmit_usec = usec;
return 0;
}
int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
assert_return(ra, -EINVAL);
if (!router_lifetime_is_valid(usec))
return -EINVAL;
ra->lifetime_usec = usec;
return 0;
}
int sd_radv_set_managed_information(sd_radv *ra, int b) {
assert_return(ra, -EINVAL);
SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, b);
return 0;
}
int sd_radv_set_other_information(sd_radv *ra, int b) {
assert_return(ra, -EINVAL);
SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, b);
return 0;
}
int sd_radv_set_preference(sd_radv *ra, uint8_t preference) {
assert_return(ra, -EINVAL);
assert_return(IN_SET(preference,
SD_NDISC_PREFERENCE_LOW,
SD_NDISC_PREFERENCE_MEDIUM,
SD_NDISC_PREFERENCE_HIGH), -EINVAL);
ra->preference = preference;
return 0;
}
/* Managing options. */
int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
assert_return(ra, -EINVAL);
return ndisc_option_set_link_layer_address(&ra->options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, mac_addr);
}
void sd_radv_unset_mac(sd_radv *ra) {
if (!ra)
return;
ndisc_option_remove_by_type(ra->options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS);
}
int sd_radv_add_prefix(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen,
uint8_t flags,
uint64_t valid_lifetime_usec,
uint64_t preferred_lifetime_usec,
uint64_t valid_until,
uint64_t preferred_until) {
assert_return(ra, -EINVAL);
assert_return(prefix, -EINVAL);
sd_ndisc_option *opt;
SET_FOREACH(opt, ra->options) {
if (opt->type != SD_NDISC_OPTION_PREFIX_INFORMATION)
continue;
if (!in6_addr_prefix_intersect(&opt->prefix.address, opt->prefix.prefixlen, prefix, prefixlen))
continue; /* no intersection */
if (opt->prefix.prefixlen == prefixlen)
break; /* same prefix */
return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
"IPv6 prefix %s conflicts with %s, ignoring.",
IN6_ADDR_PREFIX_TO_STRING(prefix, prefixlen),
IN6_ADDR_PREFIX_TO_STRING(&opt->prefix.address, opt->prefix.prefixlen));
}
return ndisc_option_set_prefix(
&ra->options,
flags,
prefixlen,
prefix,
valid_lifetime_usec,
preferred_lifetime_usec,
valid_until,
preferred_until);
}
void sd_radv_remove_prefix(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen) {
if (!ra || !prefix)
return;
ndisc_option_remove(ra->options,
&(sd_ndisc_option) {
.type = SD_NDISC_OPTION_PREFIX_INFORMATION,
.prefix.prefixlen = prefixlen,
.prefix.address = *prefix,
});
}
int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
assert_return(ra, -EINVAL);
assert_return(mtu >= IPV6_MIN_MTU, -EINVAL);
return ndisc_option_set_mtu(&ra->options, mtu);
}
void sd_radv_unset_mtu(sd_radv *ra) {
if (!ra)
return;
ndisc_option_remove_by_type(ra->options, SD_NDISC_OPTION_MTU);
}
int sd_radv_set_home_agent(sd_radv *ra, uint16_t preference, uint64_t lifetime_usec, uint64_t valid_until) {
assert_return(ra, -EINVAL);
ra->flags |= ND_RA_FLAG_HOME_AGENT;
return ndisc_option_set_home_agent(&ra->options, preference, lifetime_usec, valid_until);
}
void sd_radv_unset_home_agent(sd_radv *ra) {
if (!ra)
return;
ra->flags &= ~ND_RA_FLAG_HOME_AGENT;
ndisc_option_remove_by_type(ra->options, SD_NDISC_OPTION_HOME_AGENT);
}
int sd_radv_add_route(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen,
uint8_t preference,
uint64_t lifetime_usec,
uint64_t valid_until) {
assert_return(ra, -EINVAL);
assert_return(prefix, -EINVAL);
return ndisc_option_set_route(
&ra->options,
preference,
prefixlen,
prefix,
lifetime_usec,
valid_until);
}
void sd_radv_remove_route(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen) {
if (!ra || !prefix)
return;
ndisc_option_remove(ra->options,
&(sd_ndisc_option) {
.type = SD_NDISC_OPTION_ROUTE_INFORMATION,
.route.prefixlen = prefixlen,
.route.address = *prefix,
});
}
int sd_radv_add_rdnss(
sd_radv *ra,
size_t n_dns,
const struct in6_addr *dns,
uint64_t lifetime_usec,
uint64_t valid_until) {
assert_return(ra, -EINVAL);
assert_return(dns, -EINVAL);
return ndisc_option_set_rdnss(
&ra->options,
n_dns,
dns,
lifetime_usec,
valid_until);
}
void sd_radv_clear_rdnss(sd_radv *ra) {
if (!ra)
return;
sd_ndisc_option *opt;
SET_FOREACH(opt, ra->options)
if (opt->type == SD_NDISC_OPTION_RDNSS)
ndisc_option_remove(ra->options, opt);
}
int sd_radv_add_dnssl(
sd_radv *ra,
char * const *domains,
uint64_t lifetime_usec,
uint64_t valid_until) {
assert_return(ra, -EINVAL);
return ndisc_option_set_dnssl(
&ra->options,
domains,
lifetime_usec,
valid_until);
}
void sd_radv_clear_dnssl(sd_radv *ra) {
if (!ra)
return;
sd_ndisc_option *opt;
SET_FOREACH(opt, ra->options)
if (opt->type == SD_NDISC_OPTION_DNSSL)
ndisc_option_remove(ra->options, opt);
}
int sd_radv_set_captive_portal(sd_radv *ra, const char *portal) {
assert_return(ra, -EINVAL);
assert_return(portal, -EINVAL);
return ndisc_option_set_captive_portal(&ra->options, portal);
}
void sd_radv_unset_captive_portal(sd_radv *ra) {
if (!ra)
return;
ndisc_option_remove_by_type(ra->options, SD_NDISC_OPTION_CAPTIVE_PORTAL);
}
int sd_radv_add_prefix64(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen,
uint64_t lifetime_usec,
uint64_t valid_until) {
assert_return(ra, -EINVAL);
assert_return(prefix, -EINVAL);
return ndisc_option_set_prefix64(
&ra->options,
prefixlen,
prefix,
lifetime_usec,
valid_until);
}
void sd_radv_remove_prefix64(
sd_radv *ra,
const struct in6_addr *prefix,
uint8_t prefixlen) {
if (!ra || !prefix)
return;
ndisc_option_remove(ra->options,
&(sd_ndisc_option) {
.type = SD_NDISC_OPTION_PREF64,
.prefix64.prefixlen = prefixlen,
.prefix64.prefix = *prefix,
});
}
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