/*-*- 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 <netinet/ether.h>
#include <linux/if.h>

#include "sd-event.h"
#include "event-util.h"
#include "sd-rtnl.h"
#include "rtnl-util.h"
#include "sd-daemon.h"
#include "sd-network.h"
#include "network-util.h"
#include "network-internal.h"
#include "networkd-wait-online.h"

#include "conf-parser.h"
#include "strv.h"
#include "util.h"

static bool all_configured(Manager *m) {
        _cleanup_free_ unsigned *indices = NULL;
        char **ifname;
        bool one_ready = false;
        int r, n, i;

        n = sd_network_get_ifindices(&indices);
        if (n <= 0)
                return false;

        STRV_FOREACH(ifname, m->expected_links) {
                _cleanup_rtnl_message_unref_ sd_rtnl_message *message = NULL, *reply = NULL;
                bool found = false;
                int index;

                r = sd_rtnl_message_new_link(m->rtnl, &message, RTM_GETLINK, 0);
                if (r < 0) {
                        log_warning("colud not create GETLINK message: %s", strerror(-r));
                        return false;
                }

                r = sd_rtnl_message_append_string(message, IFLA_IFNAME, *ifname);
                if (r < 0) {
                        log_warning("could not attach ifname to GETLINK message: %s", strerror(-r));
                        return false;
                }

                r = sd_rtnl_call(m->rtnl, message, 0, &reply);
                if (r < 0) {
                        if (r != -ENODEV)
                                log_warning("could not get link info for %s: %s", *ifname,
                                            strerror(-r));

                        /* link does not yet exist */
                        return false;
                }

                r = sd_rtnl_message_link_get_ifindex(reply, &index);
                if (r < 0) {
                        log_warning("could not get ifindex: %s", strerror(-r));
                        return false;
                }

                if (index <= 0) {
                        log_warning("invalid ifindex %d for %s", index, *ifname);
                        return false;
                }

                for (i = 0; i < n; i++) {
                        if (indices[i] == (unsigned) index) {
                                found = true;
                                break;
                        }
                }

                if (!found)
                        /* link exists, but networkd is not yet aware of it */
                        return false;
        }

        for (i = 0; i < n; i++) {
                _cleanup_free_ char *state = NULL;

                r = sd_network_get_link_state(indices[i], &state);
                if (r == -EUNATCH) {
                        _cleanup_rtnl_message_unref_ sd_rtnl_message *message = NULL, *reply = NULL;
                        unsigned flags;
                        uint8_t operstate;

                        r = sd_rtnl_message_new_link(m->rtnl, &message, RTM_GETLINK, indices[i]);
                        if (r < 0) {
                                log_warning("could not create GETLINK message: %s", strerror(-r));
                                return false;
                        }

                        r = sd_rtnl_call(m->rtnl, message, 0, &reply);
                        if (r < 0) {
                                log_debug("could not get link %u: %s", indices[i], strerror(-r));
                                continue;
                        }

                        r = sd_rtnl_message_link_get_flags(reply, &flags);
                        if (r < 0) {
                                log_warning("could not get link flags: %s", strerror(-r));
                                return false;
                        }

                        r = sd_rtnl_message_read_u8(reply, IFLA_OPERSTATE, &operstate);
                        if (r < 0) {
                                log_debug("could not get link operational state: %s", strerror(-r));
                                operstate = IF_OPER_UNKNOWN;
                        }
                        
                        if (!(flags & IFF_LOOPBACK) &&
                            link_has_carrier(flags, operstate)) {
                                /* this link is not managed by us,
                                   but something else may have
                                   made it ready, so don't block */
                                one_ready = true;
                        }

                        continue;
                } else if (r < 0 || !streq(state, "configured"))
                        return false;

                /* we wait for at least one link to appear */
                one_ready = true;
        }

        return one_ready;
}

static int monitor_event_handler(sd_event_source *s, int fd, uint32_t revents,
                         void *userdata) {
        Manager *m = userdata;

        assert(m);
        assert(m->event);

        if (all_configured(m))
                sd_event_exit(m->event, 0);

        return 1;
}

static int newlink_event_handler(sd_rtnl *rtnl, sd_rtnl_message *message, void *userdata) {
        Manager *m = userdata;

        assert(m);
        assert(m->event);

        if (all_configured(m))
                sd_event_exit(m->event, 0);

        return 1;
}

static int parse_config_file(Manager *m) {
        static const char fn[] = "/etc/systemd/networkd-wait-online.conf";
        _cleanup_fclose_ FILE *f = NULL;
        int r;

        f = fopen(fn, "re");
        if (!f) {
                if (errno == ENOENT)
                        return 0;

                log_warning("Failed to open configuration file %s: %m", fn);
                return -errno;
        }

        r = config_parse(NULL, fn, f, "WaitOnline\0", config_item_perf_lookup,
                         (void*) wait_online_gperf_lookup, false, false, m);
        if (r < 0)
                log_warning("Failed to parse configuration file: %s", strerror(-r));

        return r;
}

void manager_free(Manager *m) {
        if (!m)
                return;

        sd_event_unref(m->event);
        sd_rtnl_unref(m->rtnl);
        strv_free(m->expected_links);

        free(m);
}

int main(int argc, char *argv[]) {
        _cleanup_manager_free_ Manager *m = NULL;
        _cleanup_event_source_unref_ sd_event_source *event_source = NULL;
        _cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL;
        int r, fd, events;

        log_set_target(LOG_TARGET_AUTO);
        log_parse_environment();
        log_open();

        umask(0022);

        if (argc != 1) {
                log_error("This program takes no arguments.");
                r = -EINVAL;
                goto out;
        }

        m = new0(Manager, 1);
        if (!m)
                return log_oom();

        r = parse_config_file(m);
        if (r < 0)
                goto out;

        r = sd_network_monitor_new(NULL, &monitor);
        if (r < 0) {
                log_error("Could not create monitor: %s", strerror(-r));
                goto out;
        }

        r = sd_event_new(&m->event);
        if (r < 0) {
                log_error("Could not create event: %s", strerror(-r));
                goto out;
        }

        fd = sd_network_monitor_get_fd(monitor);
        if (fd < 0) {
                log_error("Could not get monitor fd: %s", strerror(-r));
                goto out;
        }

        events = sd_network_monitor_get_events(monitor);
        if (events < 0) {
                log_error("Could not get monitor events: %s", strerror(-r));
                goto out;
        }

        r = sd_event_add_io(m->event, &event_source, fd, events, &monitor_event_handler,
                            m);
        if (r < 0) {
                log_error("Could not add io event source: %s", strerror(-r));
                goto out;
        }

        r = sd_rtnl_open(&m->rtnl, RTMGRP_LINK);
        if (r < 0) {
                log_error("Could not create rtnl: %s", strerror(-r));
                goto out;
        }

        r = sd_rtnl_attach_event(m->rtnl, m->event, 0);
        if (r < 0) {
                log_error("Could not attach event to rtnl: %s", strerror(-r));
                return r;
        }

        r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, newlink_event_handler, m);
        if (r < 0)
                return r;

        if (all_configured(m)) {
                r = 0;
                goto out;
        }

        sd_notify(false,
                  "READY=1\n"
                  "STATUS=Waiting for network connections...");

        r = sd_event_loop(m->event);
        if (r < 0) {
                log_error("Event loop failed: %s", strerror(-r));
                goto out;
        }

out:
        sd_notify(false,
                  "STATUS=All interfaces configured...");

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}