sd-netlink: rename from sd-rtnl

1 files changed, 1056 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 0000000000..14cc75915d
--- /dev/null
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -0,0 +1,1056 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Tom Gundersen <teg@jklm.no>
+
+  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 <sys/socket.h>
+#include <poll.h>
+
+#include "missing.h"
+#include "macro.h"
+#include "util.h"
+#include "hashmap.h"
+
+#include "sd-netlink.h"
+#include "netlink-internal.h"
+#include "netlink-util.h"
+
+static int sd_netlink_new(sd_netlink **ret) {
+        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        rtnl = new0(sd_netlink, 1);
+        if (!rtnl)
+                return -ENOMEM;
+
+        rtnl->n_ref = REFCNT_INIT;
+
+        rtnl->fd = -1;
+
+        rtnl->sockaddr.nl.nl_family = AF_NETLINK;
+
+        rtnl->original_pid = getpid();
+
+        LIST_HEAD_INIT(rtnl->match_callbacks);
+
+        /* We guarantee that wqueue always has space for at least
+         * one entry */
+        if (!GREEDY_REALLOC(rtnl->wqueue, rtnl->wqueue_allocated, 1))
+                return -ENOMEM;
+
+        /* We guarantee that the read buffer has at least space for
+         * a message header */
+        if (!greedy_realloc((void**)&rtnl->rbuffer, &rtnl->rbuffer_allocated,
+                            sizeof(struct nlmsghdr), sizeof(uint8_t)))
+                return -ENOMEM;
+
+        /* Change notification responses have sequence 0, so we must
+         * start our request sequence numbers at 1, or we may confuse our
+         * responses with notifications from the kernel */
+        rtnl->serial = 1;
+
+        *ret = rtnl;
+        rtnl = NULL;
+
+        return 0;
+}
+
+int sd_netlink_new_from_netlink(sd_netlink **ret, int fd) {
+        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        socklen_t addrlen;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_netlink_new(&rtnl);
+        if (r < 0)
+                return r;
+
+        addrlen = sizeof(rtnl->sockaddr);
+
+        r = getsockname(fd, &rtnl->sockaddr.sa, &addrlen);
+        if (r < 0)
+                return -errno;
+
+        rtnl->fd = fd;
+
+        *ret = rtnl;
+        rtnl = NULL;
+
+        return 0;
+}
+
+static bool rtnl_pid_changed(sd_netlink *rtnl) {
+        assert(rtnl);
+
+        /* We don't support people creating an rtnl connection and
+         * keeping it around over a fork(). Let's complain. */
+
+        return rtnl->original_pid != getpid();
+}
+
+int sd_netlink_open_fd(sd_netlink **ret, int fd) {
+        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        socklen_t addrlen;
+        int r, one = 1;
+
+        assert_return(ret, -EINVAL);
+        assert_return(fd >= 0, -EINVAL);
+
+        r = sd_netlink_new(&rtnl);
+        if (r < 0)
+                return r;
+
+        r = setsockopt(fd, SOL_NETLINK, NETLINK_PKTINFO, &one, sizeof(one));
+        if (r < 0)
+                return -errno;
+
+        addrlen = sizeof(rtnl->sockaddr);
+
+        r = bind(fd, &rtnl->sockaddr.sa, addrlen);
+        /* ignore EINVAL to allow opening an already bound socket */
+        if (r < 0 && errno != EINVAL)
+                return -errno;
+
+        r = getsockname(fd, &rtnl->sockaddr.sa, &addrlen);
+        if (r < 0)
+                return -errno;
+
+        rtnl->fd = fd;
+
+        *ret = rtnl;
+        rtnl = NULL;
+
+        return 0;
+}
+
+int sd_netlink_open(sd_netlink **ret) {
+        _cleanup_close_ int fd = -1;
+        int r;
+
+        fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_ROUTE);
+        if (fd < 0)
+                return -errno;
+
+        r = sd_netlink_open_fd(ret, fd);
+        if (r < 0)
+                return r;
+
+        fd = -1;
+
+        return 0;
+}
+
+static int rtnl_join_broadcast_group(sd_netlink *rtnl, unsigned group) {
+        int r;
+
+        assert(rtnl);
+        assert(rtnl->fd >= 0);
+        assert(group > 0);
+
+        r = setsockopt(rtnl->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int sd_netlink_inc_rcvbuf(const sd_netlink *const rtnl, const int size) {
+        return fd_inc_rcvbuf(rtnl->fd, size);
+}
+
+sd_netlink *sd_netlink_ref(sd_netlink *rtnl) {
+        assert_return(rtnl, NULL);
+        assert_return(!rtnl_pid_changed(rtnl), NULL);
+
+        if (rtnl)
+                assert_se(REFCNT_INC(rtnl->n_ref) >= 2);
+
+        return rtnl;
+}
+
+sd_netlink *sd_netlink_unref(sd_netlink *rtnl) {
+        if (!rtnl)
+                return NULL;
+
+        assert_return(!rtnl_pid_changed(rtnl), NULL);
+
+        if (REFCNT_DEC(rtnl->n_ref) == 0) {
+                struct match_callback *f;
+                unsigned i;
+
+                for (i = 0; i < rtnl->rqueue_size; i++)
+                        sd_netlink_message_unref(rtnl->rqueue[i]);
+                free(rtnl->rqueue);
+
+                for (i = 0; i < rtnl->rqueue_partial_size; i++)
+                        sd_netlink_message_unref(rtnl->rqueue_partial[i]);
+                free(rtnl->rqueue_partial);
+
+                for (i = 0; i < rtnl->wqueue_size; i++)
+                        sd_netlink_message_unref(rtnl->wqueue[i]);
+                free(rtnl->wqueue);
+
+                free(rtnl->rbuffer);
+
+                hashmap_free_free(rtnl->reply_callbacks);
+                prioq_free(rtnl->reply_callbacks_prioq);
+
+                sd_event_source_unref(rtnl->io_event_source);
+                sd_event_source_unref(rtnl->time_event_source);
+                sd_event_source_unref(rtnl->exit_event_source);
+                sd_event_unref(rtnl->event);
+
+                while ((f = rtnl->match_callbacks)) {
+                        LIST_REMOVE(match_callbacks, rtnl->match_callbacks, f);
+                        free(f);
+                }
+
+                safe_close(rtnl->fd);
+                free(rtnl);
+        }
+
+        return NULL;
+}
+
+static void rtnl_seal_message(sd_netlink *rtnl, sd_netlink_message *m) {
+        assert(rtnl);
+        assert(!rtnl_pid_changed(rtnl));
+        assert(m);
+        assert(m->hdr);
+
+        /* don't use seq == 0, as that is used for broadcasts, so we
+           would get confused by replies to such messages */
+        m->hdr->nlmsg_seq = rtnl->serial++ ? : rtnl->serial++;
+
+        rtnl_message_seal(m);
+
+        return;
+}
+
+int sd_netlink_send(sd_netlink *nl,
+                 sd_netlink_message *message,
+                 uint32_t *serial) {
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+        assert_return(message, -EINVAL);
+        assert_return(!message->sealed, -EPERM);
+
+        rtnl_seal_message(nl, message);
+
+        if (nl->wqueue_size <= 0) {
+                /* send directly */
+                r = socket_write_message(nl, message);
+                if (r < 0)
+                        return r;
+                else if (r == 0) {
+                        /* nothing was sent, so let's put it on
+                         * the queue */
+                        nl->wqueue[0] = sd_netlink_message_ref(message);
+                        nl->wqueue_size = 1;
+                }
+        } else {
+                /* append to queue */
+                if (nl->wqueue_size >= RTNL_WQUEUE_MAX) {
+                        log_debug("rtnl: exhausted the write queue size (%d)", RTNL_WQUEUE_MAX);
+                        return -ENOBUFS;
+                }
+
+                if (!GREEDY_REALLOC(nl->wqueue, nl->wqueue_allocated, nl->wqueue_size + 1))
+                        return -ENOMEM;
+
+                nl->wqueue[nl->wqueue_size ++] = sd_netlink_message_ref(message);
+        }
+
+        if (serial)
+                *serial = rtnl_message_get_serial(message);
+
+        return 1;
+}
+
+int rtnl_rqueue_make_room(sd_netlink *rtnl) {
+        assert(rtnl);
+
+        if (rtnl->rqueue_size >= RTNL_RQUEUE_MAX) {
+                log_debug("rtnl: exhausted the read queue size (%d)", RTNL_RQUEUE_MAX);
+                return -ENOBUFS;
+        }
+
+        if (!GREEDY_REALLOC(rtnl->rqueue, rtnl->rqueue_allocated, rtnl->rqueue_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+int rtnl_rqueue_partial_make_room(sd_netlink *rtnl) {
+        assert(rtnl);
+
+        if (rtnl->rqueue_partial_size >= RTNL_RQUEUE_MAX) {
+                log_debug("rtnl: exhausted the partial read queue size (%d)", RTNL_RQUEUE_MAX);
+                return -ENOBUFS;
+        }
+
+        if (!GREEDY_REALLOC(rtnl->rqueue_partial, rtnl->rqueue_partial_allocated,
+                            rtnl->rqueue_partial_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int dispatch_rqueue(sd_netlink *rtnl, sd_netlink_message **message) {
+        int r;
+
+        assert(rtnl);
+        assert(message);
+
+        if (rtnl->rqueue_size <= 0) {
+                /* Try to read a new message */
+                r = socket_read_message(rtnl);
+                if (r <= 0)
+                        return r;
+        }
+
+        /* Dispatch a queued message */
+        *message = rtnl->rqueue[0];
+        rtnl->rqueue_size --;
+        memmove(rtnl->rqueue, rtnl->rqueue + 1, sizeof(sd_netlink_message*) * rtnl->rqueue_size);
+
+        return 1;
+}
+
+static int dispatch_wqueue(sd_netlink *rtnl) {
+        int r, ret = 0;
+
+        assert(rtnl);
+
+        while (rtnl->wqueue_size > 0) {
+                r = socket_write_message(rtnl, rtnl->wqueue[0]);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        /* Didn't do anything this time */
+                        return ret;
+                else {
+                        /* see equivalent in sd-bus.c */
+                        sd_netlink_message_unref(rtnl->wqueue[0]);
+                        rtnl->wqueue_size --;
+                        memmove(rtnl->wqueue, rtnl->wqueue + 1, sizeof(sd_netlink_message*) * rtnl->wqueue_size);
+
+                        ret = 1;
+                }
+        }
+
+        return ret;
+}
+
+static int process_timeout(sd_netlink *rtnl) {
+        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        struct reply_callback *c;
+        usec_t n;
+        int r;
+
+        assert(rtnl);
+
+        c = prioq_peek(rtnl->reply_callbacks_prioq);
+        if (!c)
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout > n)
+                return 0;
+
+        r = rtnl_message_new_synthetic_error(-ETIMEDOUT, c->serial, &m);
+        if (r < 0)
+                return r;
+
+        assert_se(prioq_pop(rtnl->reply_callbacks_prioq) == c);
+        hashmap_remove(rtnl->reply_callbacks, &c->serial);
+
+        r = c->callback(rtnl, m, c->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: timedout callback failed: %m");
+
+        free(c);
+
+        return 1;
+}
+
+static int process_reply(sd_netlink *rtnl, sd_netlink_message *m) {
+        _cleanup_free_ struct reply_callback *c = NULL;
+        uint64_t serial;
+        uint16_t type;
+        int r;
+
+        assert(rtnl);
+        assert(m);
+
+        serial = rtnl_message_get_serial(m);
+        c = hashmap_remove(rtnl->reply_callbacks, &serial);
+        if (!c)
+                return 0;
+
+        if (c->timeout != 0)
+                prioq_remove(rtnl->reply_callbacks_prioq, c, &c->prioq_idx);
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return 0;
+
+        if (type == NLMSG_DONE)
+                m = NULL;
+
+        r = c->callback(rtnl, m, c->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: callback failed: %m");
+
+        return 1;
+}
+
+static int process_match(sd_netlink *rtnl, sd_netlink_message *m) {
+        struct match_callback *c;
+        uint16_t type;
+        int r;
+
+        assert(rtnl);
+        assert(m);
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        LIST_FOREACH(match_callbacks, c, rtnl->match_callbacks) {
+                if (type == c->type) {
+                        r = c->callback(rtnl, m, c->userdata);
+                        if (r != 0) {
+                                if (r < 0)
+                                        log_debug_errno(r, "sd-netlink: match callback failed: %m");
+
+                                break;
+                        }
+                }
+        }
+
+        return 1;
+}
+
+static int process_running(sd_netlink *rtnl, sd_netlink_message **ret) {
+        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        int r;
+
+        assert(rtnl);
+
+        r = process_timeout(rtnl);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_wqueue(rtnl);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_rqueue(rtnl, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        if (sd_netlink_message_is_broadcast(m)) {
+                r = process_match(rtnl, m);
+                if (r != 0)
+                        goto null_message;
+        } else {
+                r = process_reply(rtnl, m);
+                if (r != 0)
+                        goto null_message;
+        }
+
+        if (ret) {
+                *ret = m;
+                m = NULL;
+
+                return 1;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+int sd_netlink_process(sd_netlink *rtnl, sd_netlink_message **ret) {
+        RTNL_DONT_DESTROY(rtnl);
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+        assert_return(!rtnl->processing, -EBUSY);
+
+        rtnl->processing = true;
+        r = process_running(rtnl, ret);
+        rtnl->processing = false;
+
+        return r;
+}
+
+static usec_t calc_elapse(uint64_t usec) {
+        if (usec == (uint64_t) -1)
+                return 0;
+
+        if (usec == 0)
+                usec = RTNL_DEFAULT_TIMEOUT;
+
+        return now(CLOCK_MONOTONIC) + usec;
+}
+
+static int rtnl_poll(sd_netlink *rtnl, bool need_more, uint64_t timeout_usec) {
+        struct pollfd p[1] = {};
+        struct timespec ts;
+        usec_t m = USEC_INFINITY;
+        int r, e;
+
+        assert(rtnl);
+
+        e = sd_netlink_get_events(rtnl);
+        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(rtnl, &until);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        usec_t nw;
+                        nw = now(CLOCK_MONOTONIC);
+                        m = until > nw ? until - nw : 0;
+                }
+        }
+
+        if (timeout_usec != (uint64_t) -1 && (m == (uint64_t) -1 || timeout_usec < m))
+                m = timeout_usec;
+
+        p[0].fd = rtnl->fd;
+        p[0].events = e;
+
+        r = ppoll(p, 1, m == (uint64_t) -1 ? NULL : timespec_store(&ts, m), NULL);
+        if (r < 0)
+                return -errno;
+
+        return r > 0 ? 1 : 0;
+}
+
+int sd_netlink_wait(sd_netlink *nl, uint64_t timeout_usec) {
+        assert_return(nl, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+
+        if (nl->rqueue_size > 0)
+                return 0;
+
+        return rtnl_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;
+
+        if (x->timeout < y->timeout)
+                return -1;
+
+        if (x->timeout > y->timeout)
+                return 1;
+
+        return 0;
+}
+
+int sd_netlink_call_async(sd_netlink *nl,
+                       sd_netlink_message *m,
+                       sd_netlink_message_handler_t callback,
+                       void *userdata,
+                       uint64_t usec,
+                       uint32_t *serial) {
+        struct reply_callback *c;
+        uint32_t s;
+        int r, k;
+
+        assert_return(nl, -EINVAL);
+        assert_return(m, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+
+        r = hashmap_ensure_allocated(&nl->reply_callbacks, &uint64_hash_ops);
+        if (r < 0)
+                return r;
+
+        if (usec != (uint64_t) -1) {
+                r = prioq_ensure_allocated(&nl->reply_callbacks_prioq, timeout_compare);
+                if (r < 0)
+                        return r;
+        }
+
+        c = new0(struct reply_callback, 1);
+        if (!c)
+                return -ENOMEM;
+
+        c->callback = callback;
+        c->userdata = userdata;
+        c->timeout = calc_elapse(usec);
+
+        k = sd_netlink_send(nl, m, &s);
+        if (k < 0) {
+                free(c);
+                return k;
+        }
+
+        c->serial = s;
+
+        r = hashmap_put(nl->reply_callbacks, &c->serial, c);
+        if (r < 0) {
+                free(c);
+                return r;
+        }
+
+        if (c->timeout != 0) {
+                r = prioq_put(nl->reply_callbacks_prioq, c, &c->prioq_idx);
+                if (r > 0) {
+                        c->timeout = 0;
+                        sd_netlink_call_async_cancel(nl, c->serial);
+                        return r;
+                }
+        }
+
+        if (serial)
+                *serial = s;
+
+        return k;
+}
+
+int sd_netlink_call_async_cancel(sd_netlink *nl, uint32_t serial) {
+        struct reply_callback *c;
+        uint64_t s = serial;
+
+        assert_return(nl, -EINVAL);
+        assert_return(serial != 0, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+
+        c = hashmap_remove(nl->reply_callbacks, &s);
+        if (!c)
+                return 0;
+
+        if (c->timeout != 0)
+                prioq_remove(nl->reply_callbacks_prioq, c, &c->prioq_idx);
+
+        free(c);
+        return 1;
+}
+
+int sd_netlink_call(sd_netlink *rtnl,
+                sd_netlink_message *message,
+                uint64_t usec,
+                sd_netlink_message **ret) {
+        usec_t timeout;
+        uint32_t serial;
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+        assert_return(message, -EINVAL);
+
+        r = sd_netlink_send(rtnl, message, &serial);
+        if (r < 0)
+                return r;
+
+        timeout = calc_elapse(usec);
+
+        for (;;) {
+                usec_t left;
+                unsigned i;
+
+                for (i = 0; i < rtnl->rqueue_size; i++) {
+                        uint32_t received_serial;
+
+                        received_serial = rtnl_message_get_serial(rtnl->rqueue[i]);
+
+                        if (received_serial == serial) {
+                                _cleanup_netlink_message_unref_ sd_netlink_message *incoming = NULL;
+                                uint16_t type;
+
+                                incoming = rtnl->rqueue[i];
+
+                                /* found a match, remove from rqueue and return it */
+                                memmove(rtnl->rqueue + i,rtnl->rqueue + i + 1,
+                                        sizeof(sd_netlink_message*) * (rtnl->rqueue_size - i - 1));
+                                rtnl->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) {
+                                        *ret = NULL;
+                                        return 0;
+                                }
+
+                                if (ret) {
+                                        *ret = incoming;
+                                        incoming = NULL;
+                                }
+
+                                return 1;
+                        }
+                }
+
+                r = socket_read_message(rtnl);
+                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 = timeout - n;
+                } else
+                        left = (uint64_t) -1;
+
+                r = rtnl_poll(rtnl, true, left);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        return -ETIMEDOUT;
+
+                r = dispatch_wqueue(rtnl);
+                if (r < 0)
+                        return r;
+        }
+}
+
+int sd_netlink_flush(sd_netlink *rtnl) {
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        if (rtnl->wqueue_size <= 0)
+                return 0;
+
+        for (;;) {
+                r = dispatch_wqueue(rtnl);
+                if (r < 0)
+                        return r;
+
+                if (rtnl->wqueue_size <= 0)
+                        return 0;
+
+                r = rtnl_poll(rtnl, false, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
+int sd_netlink_get_events(sd_netlink *rtnl) {
+        int flags = 0;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        if (rtnl->rqueue_size <= 0)
+                flags |= POLLIN;
+        if (rtnl->wqueue_size > 0)
+                flags |= POLLOUT;
+
+        return flags;
+}
+
+int sd_netlink_get_timeout(sd_netlink *rtnl, uint64_t *timeout_usec) {
+        struct reply_callback *c;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        if (rtnl->rqueue_size > 0) {
+                *timeout_usec = 0;
+                return 1;
+        }
+
+        c = prioq_peek(rtnl->reply_callbacks_prioq);
+        if (!c) {
+                *timeout_usec = (uint64_t) -1;
+                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 *rtnl = userdata;
+        int r;
+
+        assert(rtnl);
+
+        r = sd_netlink_process(rtnl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_netlink *rtnl = userdata;
+        int r;
+
+        assert(rtnl);
+
+        r = sd_netlink_process(rtnl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_netlink *rtnl = userdata;
+        int r, e;
+        usec_t until;
+
+        assert(s);
+        assert(rtnl);
+
+        e = sd_netlink_get_events(rtnl);
+        if (e < 0)
+                return e;
+
+        r = sd_event_source_set_io_events(rtnl->io_event_source, e);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_get_timeout(rtnl, &until);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                int j;
+
+                j = sd_event_source_set_time(rtnl->time_event_source, until);
+                if (j < 0)
+                        return j;
+        }
+
+        r = sd_event_source_set_enabled(rtnl->time_event_source, r > 0);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int exit_callback(sd_event_source *event, void *userdata) {
+        sd_netlink *rtnl = userdata;
+
+        assert(event);
+
+        sd_netlink_flush(rtnl);
+
+        return 1;
+}
+
+int sd_netlink_attach_event(sd_netlink *rtnl, sd_event *event, int priority) {
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl->event, -EBUSY);
+
+        assert(!rtnl->io_event_source);
+        assert(!rtnl->time_event_source);
+
+        if (event)
+                rtnl->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&rtnl->event);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_event_add_io(rtnl->event, &rtnl->io_event_source, rtnl->fd, 0, io_callback, rtnl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(rtnl->io_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(rtnl->io_event_source, "rtnl-receive-message");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_prepare(rtnl->io_event_source, prepare_callback);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_time(rtnl->event, &rtnl->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, rtnl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(rtnl->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(rtnl->time_event_source, "rtnl-timer");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_exit(rtnl->event, &rtnl->exit_event_source, exit_callback, rtnl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(rtnl->exit_event_source, "rtnl-exit");
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_netlink_detach_event(rtnl);
+        return r;
+}
+
+int sd_netlink_detach_event(sd_netlink *rtnl) {
+        assert_return(rtnl, -EINVAL);
+        assert_return(rtnl->event, -ENXIO);
+
+        if (rtnl->io_event_source)
+                rtnl->io_event_source = sd_event_source_unref(rtnl->io_event_source);
+
+        if (rtnl->time_event_source)
+                rtnl->time_event_source = sd_event_source_unref(rtnl->time_event_source);
+
+        if (rtnl->exit_event_source)
+                rtnl->exit_event_source = sd_event_source_unref(rtnl->exit_event_source);
+
+        if (rtnl->event)
+                rtnl->event = sd_event_unref(rtnl->event);
+
+        return 0;
+}
+
+int sd_netlink_add_match(sd_netlink *rtnl,
+                      uint16_t type,
+                      sd_netlink_message_handler_t callback,
+                      void *userdata) {
+        _cleanup_free_ struct match_callback *c = NULL;
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        c = new0(struct match_callback, 1);
+        if (!c)
+                return -ENOMEM;
+
+        c->callback = callback;
+        c->type = type;
+        c->userdata = userdata;
+
+        switch (type) {
+                case RTM_NEWLINK:
+                case RTM_SETLINK:
+                case RTM_GETLINK:
+                case RTM_DELLINK:
+                        r = rtnl_join_broadcast_group(rtnl, RTNLGRP_LINK);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                case RTM_NEWADDR:
+                case RTM_GETADDR:
+                case RTM_DELADDR:
+                        r = rtnl_join_broadcast_group(rtnl, RTNLGRP_IPV4_IFADDR);
+                        if (r < 0)
+                                return r;
+
+                        r = rtnl_join_broadcast_group(rtnl, RTNLGRP_IPV6_IFADDR);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                default:
+                        return -EOPNOTSUPP;
+        }
+
+        LIST_PREPEND(match_callbacks, rtnl->match_callbacks, c);
+
+        c = NULL;
+
+        return 0;
+}
+
+int sd_netlink_remove_match(sd_netlink *rtnl,
+                         uint16_t type,
+                         sd_netlink_message_handler_t callback,
+                         void *userdata) {
+        struct match_callback *c;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        /* we should unsubscribe from the broadcast groups at this point, but it is not so
+           trivial for a few reasons: the refcounting is a bit of a mess and not obvious
+           how it will look like after we add genetlink support, and it is also not possible
+           to query what broadcast groups were subscribed to when we inherit the socket to get
+           the initial refcount. The latter could indeed be done for the first 32 broadcast
+           groups (which incidentally is all we currently support in .socket units anyway),
+           but we better not rely on only ever using 32 groups. */
+        LIST_FOREACH(match_callbacks, c, rtnl->match_callbacks)
+                if (c->callback == callback && c->type == type && c->userdata == userdata) {
+                        LIST_REMOVE(match_callbacks, rtnl->match_callbacks, c);
+                        free(c);
+
+                        return 1;
+                }
+
+        return 0;
+}