Adding upstream version 252.22.upstream/252.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 933 insertions, 0 deletions

diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
new file mode 100644
index 0000000..74f2972
--- /dev/null
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -0,0 +1,933 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <poll.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hashmap.h"
+#include "io-util.h"
+#include "macro.h"
+#include "netlink-genl.h"
+#include "netlink-internal.h"
+#include "netlink-slot.h"
+#include "netlink-util.h"
+#include "process-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+
+/* Some really high limit, to catch programming errors */
+#define REPLY_CALLBACKS_MAX UINT16_MAX
+
+static int netlink_new(sd_netlink **ret) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *nl = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        nl = new(sd_netlink, 1);
+        if (!nl)
+                return -ENOMEM;
+
+        *nl = (sd_netlink) {
+                .n_ref = 1,
+                .fd = -1,
+                .sockaddr.nl.nl_family = AF_NETLINK,
+                .original_pid = getpid_cached(),
+                .protocol = -1,
+
+                /* Kernel change notification messages have sequence number 0. We want to avoid that with our
+                 * own serials, in order not to get confused when matching up kernel replies to our earlier
+                 * requests.
+                 *
+                 * Moreover, when using netlink socket activation (i.e. where PID 1 binds an AF_NETLINK
+                 * socket for us and passes it to us across execve()) and we get restarted multiple times
+                 * while the socket sticks around we might get confused by replies from earlier runs coming
+                 * in late — which is pretty likely if we'd start our sequence numbers always from 1. Hence,
+                 * let's start with a value based on the system clock. This should make collisions much less
+                 * likely (though still theoretically possible). We use a 32 bit µs counter starting at boot
+                 * for this (and explicitly exclude the zero, see above). This counter will wrap around after
+                 * a bit more than 1h, but that's hopefully OK as the kernel shouldn't take that long to
+                 * reply to our requests.
+                 *
+                 * We only pick the initial start value this way. For each message we simply increase the
+                 * sequence number by 1. This means we could enqueue 1 netlink message per µs without risking
+                 * collisions, which should be OK.
+                 *
+                 * Note this means the serials will be in the range 1…UINT32_MAX here.
+                 *
+                 * (In an ideal world we'd attach the current serial counter to the netlink socket itself
+                 * somehow, to avoid all this, but I couldn't come up with a nice way to do this) */
+                .serial = (uint32_t) (now(CLOCK_MONOTONIC) % UINT32_MAX) + 1,
+        };
+
+        /* We guarantee that the read buffer has at least space for a message header */
+        if (!greedy_realloc((void**) &nl->rbuffer, sizeof(struct nlmsghdr), sizeof(uint8_t)))
+                return -ENOMEM;
+
+        *ret = TAKE_PTR(nl);
+        return 0;
+}
+
+int sd_netlink_open_fd(sd_netlink **ret, int fd) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *nl = NULL;
+        int r, protocol;
+
+        assert_return(ret, -EINVAL);
+        assert_return(fd >= 0, -EBADF);
+
+        r = netlink_new(&nl);
+        if (r < 0)
+                return r;
+
+        r = getsockopt_int(fd, SOL_SOCKET, SO_PROTOCOL, &protocol);
+        if (r < 0)
+                return r;
+
+        nl->fd = fd;
+        nl->protocol = protocol;
+
+        r = setsockopt_int(fd, SOL_NETLINK, NETLINK_EXT_ACK, true);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: Failed to enable NETLINK_EXT_ACK option, ignoring: %m");
+
+        r = setsockopt_int(fd, SOL_NETLINK, NETLINK_GET_STRICT_CHK, true);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: Failed to enable NETLINK_GET_STRICT_CHK option, ignoring: %m");
+
+        r = socket_bind(nl);
+        if (r < 0) {
+                nl->fd = -1; /* on failure, the caller remains owner of the fd, hence don't close it here */
+                nl->protocol = -1;
+                return r;
+        }
+
+        *ret = TAKE_PTR(nl);
+
+        return 0;
+}
+
+int sd_netlink_open(sd_netlink **ret) {
+        return netlink_open_family(ret, NETLINK_ROUTE);
+}
+
+int sd_netlink_increase_rxbuf(sd_netlink *nl, size_t size) {
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        return fd_increase_rxbuf(nl->fd, size);
+}
+
+static sd_netlink *netlink_free(sd_netlink *nl) {
+        sd_netlink_slot *s;
+        unsigned i;
+
+        assert(nl);
+
+        for (i = 0; i < nl->rqueue_size; i++)
+                sd_netlink_message_unref(nl->rqueue[i]);
+        free(nl->rqueue);
+
+        for (i = 0; i < nl->rqueue_partial_size; i++)
+                sd_netlink_message_unref(nl->rqueue_partial[i]);
+        free(nl->rqueue_partial);
+
+        free(nl->rbuffer);
+
+        while ((s = nl->slots)) {
+                assert(s->floating);
+                netlink_slot_disconnect(s, true);
+        }
+        hashmap_free(nl->reply_callbacks);
+        prioq_free(nl->reply_callbacks_prioq);
+
+        sd_event_source_unref(nl->io_event_source);
+        sd_event_source_unref(nl->time_event_source);
+        sd_event_unref(nl->event);
+
+        hashmap_free(nl->broadcast_group_refs);
+
+        genl_clear_family(nl);
+
+        safe_close(nl->fd);
+        return mfree(nl);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_netlink, sd_netlink, netlink_free);
+
+int sd_netlink_send(
+                sd_netlink *nl,
+                sd_netlink_message *message,
+                uint32_t *serial) {
+
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+        assert_return(message, -EINVAL);
+        assert_return(!message->sealed, -EPERM);
+
+        netlink_seal_message(nl, message);
+
+        r = socket_write_message(nl, message);
+        if (r < 0)
+                return r;
+
+        if (serial)
+                *serial = message_get_serial(message);
+
+        return 1;
+}
+
+int netlink_rqueue_make_room(sd_netlink *nl) {
+        assert(nl);
+
+        if (nl->rqueue_size >= NETLINK_RQUEUE_MAX)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOBUFS),
+                                       "sd-netlink: exhausted the read queue size (%d)",
+                                       NETLINK_RQUEUE_MAX);
+
+        if (!GREEDY_REALLOC(nl->rqueue, nl->rqueue_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+int netlink_rqueue_partial_make_room(sd_netlink *nl) {
+        assert(nl);
+
+        if (nl->rqueue_partial_size >= NETLINK_RQUEUE_MAX)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOBUFS),
+                                       "sd-netlink: exhausted the partial read queue size (%d)",
+                                       NETLINK_RQUEUE_MAX);
+
+        if (!GREEDY_REALLOC(nl->rqueue_partial, nl->rqueue_partial_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int dispatch_rqueue(sd_netlink *nl, sd_netlink_message **message) {
+        int r;
+
+        assert(nl);
+        assert(message);
+
+        if (nl->rqueue_size <= 0) {
+                /* Try to read a new message */
+                r = socket_read_message(nl);
+                if (r == -ENOBUFS) { /* FIXME: ignore buffer overruns for now */
+                        log_debug_errno(r, "sd-netlink: Got ENOBUFS from netlink socket, ignoring.");
+                        return 1;
+                }
+                if (r <= 0)
+                        return r;
+        }
+
+        /* Dispatch a queued message */
+        *message = nl->rqueue[0];
+        nl->rqueue_size--;
+        memmove(nl->rqueue, nl->rqueue + 1, sizeof(sd_netlink_message*) * nl->rqueue_size);
+
+        return 1;
+}
+
+static int process_timeout(sd_netlink *nl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        struct reply_callback *c;
+        sd_netlink_slot *slot;
+        usec_t n;
+        int r;
+
+        assert(nl);
+
+        c = prioq_peek(nl->reply_callbacks_prioq);
+        if (!c)
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout > n)
+                return 0;
+
+        r = message_new_synthetic_error(nl, -ETIMEDOUT, c->serial, &m);
+        if (r < 0)
+                return r;
+
+        assert_se(prioq_pop(nl->reply_callbacks_prioq) == c);
+        c->timeout = 0;
+        hashmap_remove(nl->reply_callbacks, UINT32_TO_PTR(c->serial));
+
+        slot = container_of(c, sd_netlink_slot, reply_callback);
+
+        r = c->callback(nl, m, slot->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: timedout callback %s%s%sfailed: %m",
+                                slot->description ? "'" : "",
+                                strempty(slot->description),
+                                slot->description ? "' " : "");
+
+        if (slot->floating)
+                netlink_slot_disconnect(slot, true);
+
+        return 1;
+}
+
+static int process_reply(sd_netlink *nl, sd_netlink_message *m) {
+        struct reply_callback *c;
+        sd_netlink_slot *slot;
+        uint32_t serial;
+        uint16_t type;
+        int r;
+
+        assert(nl);
+        assert(m);
+
+        serial = message_get_serial(m);
+        c = hashmap_remove(nl->reply_callbacks, UINT32_TO_PTR(serial));
+        if (!c)
+                return 0;
+
+        if (c->timeout != 0) {
+                prioq_remove(nl->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout = 0;
+        }
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        if (type == NLMSG_DONE)
+                m = NULL;
+
+        slot = container_of(c, sd_netlink_slot, reply_callback);
+
+        r = c->callback(nl, m, slot->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: reply callback %s%s%sfailed: %m",
+                                slot->description ? "'" : "",
+                                strempty(slot->description),
+                                slot->description ? "' " : "");
+
+        if (slot->floating)
+                netlink_slot_disconnect(slot, true);
+
+        return 1;
+}
+
+static int process_match(sd_netlink *nl, sd_netlink_message *m) {
+        uint16_t type;
+        uint8_t cmd;
+        int r;
+
+        assert(nl);
+        assert(m);
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        if (m->protocol == NETLINK_GENERIC) {
+                r = sd_genl_message_get_command(nl, m, &cmd);
+                if (r < 0)
+                        return r;
+        } else
+                cmd = 0;
+
+        LIST_FOREACH(match_callbacks, c, nl->match_callbacks) {
+                sd_netlink_slot *slot;
+                bool found = false;
+
+                if (c->type != type)
+                        continue;
+                if (c->cmd != 0 && c->cmd != cmd)
+                        continue;
+
+                for (size_t i = 0; i < c->n_groups; i++)
+                        if (c->groups[i] == m->multicast_group) {
+                                found = true;
+                                break;
+                        }
+
+                if (!found)
+                        continue;
+
+                slot = container_of(c, sd_netlink_slot, match_callback);
+
+                r = c->callback(nl, m, slot->userdata);
+                if (r < 0)
+                        log_debug_errno(r, "sd-netlink: match callback %s%s%sfailed: %m",
+                                        slot->description ? "'" : "",
+                                        strempty(slot->description),
+                                        slot->description ? "' " : "");
+                if (r != 0)
+                        break;
+        }
+
+        return 1;
+}
+
+static int process_running(sd_netlink *nl, sd_netlink_message **ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        int r;
+
+        assert(nl);
+
+        r = process_timeout(nl);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_rqueue(nl, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        if (sd_netlink_message_is_broadcast(m))
+                r = process_match(nl, m);
+        else
+                r = process_reply(nl, m);
+        if (r != 0)
+                goto null_message;
+
+        if (ret) {
+                *ret = TAKE_PTR(m);
+
+                return 1;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+int sd_netlink_process(sd_netlink *nl, sd_netlink_message **ret) {
+        NETLINK_DONT_DESTROY(nl);
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+        assert_return(!nl->processing, -EBUSY);
+
+        nl->processing = true;
+        r = process_running(nl, ret);
+        nl->processing = false;
+
+        return r;
+}
+
+static usec_t calc_elapse(uint64_t usec) {
+        if (usec == UINT64_MAX)
+                return 0;
+
+        if (usec == 0)
+                usec = NETLINK_DEFAULT_TIMEOUT_USEC;
+
+        return usec_add(now(CLOCK_MONOTONIC), usec);
+}
+
+static int netlink_poll(sd_netlink *nl, bool need_more, usec_t timeout_usec) {
+        usec_t m = USEC_INFINITY;
+        int r, e;
+
+        assert(nl);
+
+        e = sd_netlink_get_events(nl);
+        if (e < 0)
+                return e;
+
+        if (need_more)
+                /* Caller wants more data, and doesn't care about
+                 * what's been read or any other timeouts. */
+                e |= POLLIN;
+        else {
+                usec_t until;
+
+                /* Caller wants to process if there is something to
+                 * process, but doesn't care otherwise */
+
+                r = sd_netlink_get_timeout(nl, &until);
+                if (r < 0)
+                        return r;
+
+                m = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+        }
+
+        r = fd_wait_for_event(nl->fd, e, MIN(m, timeout_usec));
+        if (r <= 0)
+                return r;
+
+        return 1;
+}
+
+int sd_netlink_wait(sd_netlink *nl, uint64_t timeout_usec) {
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        if (nl->rqueue_size > 0)
+                return 0;
+
+        return netlink_poll(nl, false, timeout_usec);
+}
+
+static int timeout_compare(const void *a, const void *b) {
+        const struct reply_callback *x = a, *y = b;
+
+        if (x->timeout != 0 && y->timeout == 0)
+                return -1;
+
+        if (x->timeout == 0 && y->timeout != 0)
+                return 1;
+
+        return CMP(x->timeout, y->timeout);
+}
+
+int sd_netlink_call_async(
+                sd_netlink *nl,
+                sd_netlink_slot **ret_slot,
+                sd_netlink_message *m,
+                sd_netlink_message_handler_t callback,
+                sd_netlink_destroy_t destroy_callback,
+                void *userdata,
+                uint64_t usec,
+                const char *description) {
+
+        _cleanup_free_ sd_netlink_slot *slot = NULL;
+        int r, k;
+
+        assert_return(nl, -EINVAL);
+        assert_return(m, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        if (hashmap_size(nl->reply_callbacks) >= REPLY_CALLBACKS_MAX)
+                return -ERANGE;
+
+        r = hashmap_ensure_allocated(&nl->reply_callbacks, &trivial_hash_ops);
+        if (r < 0)
+                return r;
+
+        if (usec != UINT64_MAX) {
+                r = prioq_ensure_allocated(&nl->reply_callbacks_prioq, timeout_compare);
+                if (r < 0)
+                        return r;
+        }
+
+        r = netlink_slot_allocate(nl, !ret_slot, NETLINK_REPLY_CALLBACK, sizeof(struct reply_callback), userdata, description, &slot);
+        if (r < 0)
+                return r;
+
+        slot->reply_callback.callback = callback;
+        slot->reply_callback.timeout = calc_elapse(usec);
+
+        k = sd_netlink_send(nl, m, &slot->reply_callback.serial);
+        if (k < 0)
+                return k;
+
+        r = hashmap_put(nl->reply_callbacks, UINT32_TO_PTR(slot->reply_callback.serial), &slot->reply_callback);
+        if (r < 0)
+                return r;
+
+        if (slot->reply_callback.timeout != 0) {
+                r = prioq_put(nl->reply_callbacks_prioq, &slot->reply_callback, &slot->reply_callback.prioq_idx);
+                if (r < 0) {
+                        (void) hashmap_remove(nl->reply_callbacks, UINT32_TO_PTR(slot->reply_callback.serial));
+                        return r;
+                }
+        }
+
+        /* Set this at last. Otherwise, some failures in above would call destroy_callback but some would not. */
+        slot->destroy_callback = destroy_callback;
+
+        if (ret_slot)
+                *ret_slot = slot;
+
+        TAKE_PTR(slot);
+
+        return k;
+}
+
+int sd_netlink_read(
+                sd_netlink *nl,
+                uint32_t serial,
+                uint64_t usec,
+                sd_netlink_message **ret) {
+
+        usec_t timeout;
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        timeout = calc_elapse(usec);
+
+        for (;;) {
+                usec_t left;
+
+                for (unsigned i = 0; i < nl->rqueue_size; i++) {
+                        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *incoming = NULL;
+                        uint32_t received_serial;
+                        uint16_t type;
+
+                        received_serial = message_get_serial(nl->rqueue[i]);
+                        if (received_serial != serial)
+                                continue;
+
+                        incoming = nl->rqueue[i];
+
+                        /* found a match, remove from rqueue and return it */
+                        memmove(nl->rqueue + i, nl->rqueue + i + 1,
+                                sizeof(sd_netlink_message*) * (nl->rqueue_size - i - 1));
+                        nl->rqueue_size--;
+
+                        r = sd_netlink_message_get_errno(incoming);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_netlink_message_get_type(incoming, &type);
+                        if (r < 0)
+                                return r;
+
+                        if (type == NLMSG_DONE) {
+                                if (ret)
+                                        *ret = NULL;
+                                return 0;
+                        }
+
+                        if (ret)
+                                *ret = TAKE_PTR(incoming);
+                        return 1;
+                }
+
+                r = socket_read_message(nl);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        /* received message, so try to process straight away */
+                        continue;
+
+                if (timeout > 0) {
+                        usec_t n;
+
+                        n = now(CLOCK_MONOTONIC);
+                        if (n >= timeout)
+                                return -ETIMEDOUT;
+
+                        left = usec_sub_unsigned(timeout, n);
+                } else
+                        left = USEC_INFINITY;
+
+                r = netlink_poll(nl, true, left);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ETIMEDOUT;
+        }
+}
+
+int sd_netlink_call(
+                sd_netlink *nl,
+                sd_netlink_message *message,
+                uint64_t usec,
+                sd_netlink_message **ret) {
+
+        uint32_t serial;
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+        assert_return(message, -EINVAL);
+
+        r = sd_netlink_send(nl, message, &serial);
+        if (r < 0)
+                return r;
+
+        return sd_netlink_read(nl, serial, usec, ret);
+}
+
+int sd_netlink_get_events(sd_netlink *nl) {
+        assert_return(nl, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        return nl->rqueue_size == 0 ? POLLIN : 0;
+}
+
+int sd_netlink_get_timeout(sd_netlink *nl, uint64_t *timeout_usec) {
+        struct reply_callback *c;
+
+        assert_return(nl, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(!netlink_pid_changed(nl), -ECHILD);
+
+        if (nl->rqueue_size > 0) {
+                *timeout_usec = 0;
+                return 1;
+        }
+
+        c = prioq_peek(nl->reply_callbacks_prioq);
+        if (!c) {
+                *timeout_usec = UINT64_MAX;
+                return 0;
+        }
+
+        *timeout_usec = c->timeout;
+
+        return 1;
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_netlink *nl = ASSERT_PTR(userdata);
+        int r;
+
+        r = sd_netlink_process(nl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_netlink *nl = ASSERT_PTR(userdata);
+        int r;
+
+        r = sd_netlink_process(nl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_netlink *nl = ASSERT_PTR(userdata);
+        int r, enabled;
+        usec_t until;
+
+        assert(s);
+
+        r = sd_netlink_get_events(nl);
+        if (r < 0)
+                return r;
+
+        r = sd_event_source_set_io_events(nl->io_event_source, r);
+        if (r < 0)
+                return r;
+
+        enabled = sd_netlink_get_timeout(nl, &until);
+        if (enabled < 0)
+                return enabled;
+        if (enabled > 0) {
+                r = sd_event_source_set_time(nl->time_event_source, until);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_event_source_set_enabled(nl->time_event_source,
+                                        enabled > 0 ? SD_EVENT_ONESHOT : SD_EVENT_OFF);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int sd_netlink_attach_event(sd_netlink *nl, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!nl->event, -EBUSY);
+
+        assert(!nl->io_event_source);
+        assert(!nl->time_event_source);
+
+        if (event)
+                nl->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&nl->event);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_event_add_io(nl->event, &nl->io_event_source, nl->fd, 0, io_callback, nl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(nl->io_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(nl->io_event_source, "netlink-receive-message");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_prepare(nl->io_event_source, prepare_callback);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_time(nl->event, &nl->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, nl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(nl->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(nl->time_event_source, "netlink-timer");
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_netlink_detach_event(nl);
+        return r;
+}
+
+int sd_netlink_detach_event(sd_netlink *nl) {
+        assert_return(nl, -EINVAL);
+        assert_return(nl->event, -ENXIO);
+
+        nl->io_event_source = sd_event_source_unref(nl->io_event_source);
+
+        nl->time_event_source = sd_event_source_unref(nl->time_event_source);
+
+        nl->event = sd_event_unref(nl->event);
+
+        return 0;
+}
+
+int netlink_add_match_internal(
+                sd_netlink *nl,
+                sd_netlink_slot **ret_slot,
+                const uint32_t *groups,
+                size_t n_groups,
+                uint16_t type,
+                uint8_t cmd,
+                sd_netlink_message_handler_t callback,
+                sd_netlink_destroy_t destroy_callback,
+                void *userdata,
+                const char *description) {
+
+        _cleanup_free_ sd_netlink_slot *slot = NULL;
+        int r;
+
+        assert(groups);
+        assert(n_groups > 0);
+
+        for (size_t i = 0; i < n_groups; i++) {
+                r = socket_broadcast_group_ref(nl, groups[i]);
+                if (r < 0)
+                        return r;
+        }
+
+        r = netlink_slot_allocate(nl, !ret_slot, NETLINK_MATCH_CALLBACK, sizeof(struct match_callback),
+                                  userdata, description, &slot);
+        if (r < 0)
+                return r;
+
+        slot->match_callback.groups = newdup(uint32_t, groups, n_groups);
+        if (!slot->match_callback.groups)
+                return -ENOMEM;
+
+        slot->match_callback.n_groups = n_groups;
+        slot->match_callback.callback = callback;
+        slot->match_callback.type = type;
+        slot->match_callback.cmd = cmd;
+
+        LIST_PREPEND(match_callbacks, nl->match_callbacks, &slot->match_callback);
+
+        /* Set this at last. Otherwise, some failures in above call the destroy callback but some do not. */
+        slot->destroy_callback = destroy_callback;
+
+        if (ret_slot)
+                *ret_slot = slot;
+
+        TAKE_PTR(slot);
+        return 0;
+}
+
+int sd_netlink_add_match(
+                sd_netlink *rtnl,
+                sd_netlink_slot **ret_slot,
+                uint16_t type,
+                sd_netlink_message_handler_t callback,
+                sd_netlink_destroy_t destroy_callback,
+                void *userdata,
+                const char *description) {
+
+        static const uint32_t
+                address_groups[]  = { RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR, },
+                link_groups[]     = { RTNLGRP_LINK, },
+                neighbor_groups[] = { RTNLGRP_NEIGH, },
+                nexthop_groups[]  = { RTNLGRP_NEXTHOP, },
+                route_groups[]    = { RTNLGRP_IPV4_ROUTE, RTNLGRP_IPV6_ROUTE, },
+                rule_groups[]     = { RTNLGRP_IPV4_RULE, RTNLGRP_IPV6_RULE, },
+                tc_groups[]       = { RTNLGRP_TC };
+        const uint32_t *groups;
+        size_t n_groups;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!netlink_pid_changed(rtnl), -ECHILD);
+
+        switch (type) {
+                case RTM_NEWLINK:
+                case RTM_DELLINK:
+                        groups = link_groups;
+                        n_groups = ELEMENTSOF(link_groups);
+                        break;
+                case RTM_NEWADDR:
+                case RTM_DELADDR:
+                        groups = address_groups;
+                        n_groups = ELEMENTSOF(address_groups);
+                        break;
+                case RTM_NEWNEIGH:
+                case RTM_DELNEIGH:
+                        groups = neighbor_groups;
+                        n_groups = ELEMENTSOF(neighbor_groups);
+                        break;
+                case RTM_NEWROUTE:
+                case RTM_DELROUTE:
+                        groups = route_groups;
+                        n_groups = ELEMENTSOF(route_groups);
+                        break;
+                case RTM_NEWRULE:
+                case RTM_DELRULE:
+                        groups = rule_groups;
+                        n_groups = ELEMENTSOF(rule_groups);
+                        break;
+                case RTM_NEWNEXTHOP:
+                case RTM_DELNEXTHOP:
+                        groups = nexthop_groups;
+                        n_groups = ELEMENTSOF(nexthop_groups);
+                        break;
+                case RTM_NEWQDISC:
+                case RTM_DELQDISC:
+                case RTM_NEWTCLASS:
+                case RTM_DELTCLASS:
+                        groups = tc_groups;
+                        n_groups = ELEMENTSOF(tc_groups);
+                        break;
+                default:
+                        return -EOPNOTSUPP;
+        }
+
+        return netlink_add_match_internal(rtnl, ret_slot, groups, n_groups, type, 0, callback,
+                                          destroy_callback, userdata, description);
+}
+
+int sd_netlink_attach_filter(sd_netlink *nl, size_t len, const struct sock_filter *filter) {
+        assert_return(nl, -EINVAL);
+        assert_return(len == 0 || filter, -EINVAL);
+
+        if (setsockopt(nl->fd, SOL_SOCKET,
+                       len == 0 ? SO_DETACH_FILTER : SO_ATTACH_FILTER,
+                       &(struct sock_fprog) {
+                               .len = len,
+                               .filter = (struct sock_filter*) filter,
+                       }, sizeof(struct sock_fprog)) < 0)
+                return -errno;
+
+        return 0;
+}