/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2011 Lennart Poettering
  Copyright 2014 Tom Gundersen

  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 <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/inotify.h>
#include <sys/poll.h>
#include <net/if.h>

#include "util.h"
#include "macro.h"
#include "strv.h"
#include "fileio.h"
#include "sd-network.h"
#include "dhcp-lease-internal.h"

static int link_get_flags(unsigned index, unsigned *flags) {
        _cleanup_free_ char *s = NULL, *p = NULL;
        int r;

        assert(index);
        assert(flags);

        if (asprintf(&p, "/run/systemd/network/links/%u", index) < 0)
                return -ENOMEM;

        r = parse_env_file(p, NEWLINE, "FLAGS", &s, NULL);
        if (r == -ENOENT)
                return -ENODATA;
        else if (r < 0)
                return r;
        else if (!s)
                return -EIO;

        return safe_atou(s, flags);
}

_public_ int sd_network_link_is_loopback(unsigned index) {
        unsigned flags;
        int r;

        r = link_get_flags(index, &flags);
        if (r < 0)
                return 0;

        return flags & IFF_LOOPBACK;
}

_public_ int sd_network_get_link_state(unsigned index, char **state) {
        _cleanup_free_ char *s = NULL, *p = NULL;
        int r;

        assert_return(index, -EINVAL);
        assert_return(state, -EINVAL);

        if (asprintf(&p, "/run/systemd/network/links/%u", index) < 0)
                return -ENOMEM;

        r = parse_env_file(p, NEWLINE, "ADMIN_STATE", &s, NULL);
        if (r == -ENOENT)
                return -ENODATA;
        else if (r < 0)
                return r;
        else if (!s)
                return -EIO;

        if (streq(s, "unmanaged"))
                return -EUNATCH;
        else if (streq(s, "initializing"))
                return -EBUSY;

        *state = s;
        s = NULL;

        return 0;
}

_public_ int sd_network_get_link_operational_state(unsigned index, char **state) {
        _cleanup_free_ char *s = NULL, *p = NULL;
        int r;

        assert_return(index, -EINVAL);
        assert_return(state, -EINVAL);

        if (asprintf(&p, "/run/systemd/network/links/%u", index) < 0)
                return -ENOMEM;

        r = parse_env_file(p, NEWLINE, "OPER_STATE", &s, NULL);
        if (r == -ENOENT)
                return -ENODATA;
        else if (r < 0)
                return r;
        else if (!s)
                return -EIO;

        *state = s;
        s = NULL;

        return 0;
}

_public_ int sd_network_get_dhcp_lease(unsigned index, sd_dhcp_lease **ret) {
        sd_dhcp_lease *lease;
        char *p, *s = NULL;
        int r;

        assert_return(index, -EINVAL);
        assert_return(ret, -EINVAL);

        if (asprintf(&p, "/run/systemd/network/links/%u", index) < 0)
                return -ENOMEM;

        r = parse_env_file(p, NEWLINE, "DHCP_LEASE", &s, NULL);
        free(p);

        if (r < 0) {
                free(s);
                return r;
        } else if (!s)
                return -EIO;

        r = dhcp_lease_load(s, &lease);
        if (r < 0)
                return r;

        *ret = lease;

        return 0;
}

_public_ int sd_network_get_ifindices(unsigned **indices) {
        _cleanup_closedir_ DIR *d;
        int r = 0;
        unsigned n = 0;
        _cleanup_free_ uid_t *l = NULL;

        d = opendir("/run/systemd/network/links/");
        if (!d)
                return -errno;

        for (;;) {
                struct dirent *de;
                int k;
                unsigned index;

                errno = 0;
                de = readdir(d);
                if (!de && errno != 0)
                        return -errno;

                if (!de)
                        break;

                dirent_ensure_type(d, de);

                if (!dirent_is_file(de))
                        continue;

                k = safe_atou(de->d_name, &index);
                if (k < 0)
                        continue;

                if (indices) {
                        if ((unsigned) r >= n) {
                                unsigned *t;

                                n = MAX(16, 2*r);
                                t = realloc(l, sizeof(unsigned) * n);
                                if (!t)
                                        return -ENOMEM;

                                l = t;
                        }

                        assert((unsigned) r < n);
                        l[r++] = index;
                } else
                        r++;
        }

        if (indices) {
                *indices = l;
                l = NULL;
        }

        return r;
}

static inline int MONITOR_TO_FD(sd_network_monitor *m) {
        return (int) (unsigned long) m - 1;
}

static inline sd_network_monitor* FD_TO_MONITOR(int fd) {
        return (sd_network_monitor*) (unsigned long) (fd + 1);
}

_public_ int sd_network_monitor_new(const char *category, sd_network_monitor **m) {
        int fd, k;
        bool good = false;

        assert_return(m, -EINVAL);

        fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
        if (fd < 0)
                return -errno;

        if (!category || streq(category, "links")) {
                k = inotify_add_watch(fd, "/run/systemd/network/links/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!category || streq(category, "leases")) {
                k = inotify_add_watch(fd, "/run/systemd/network/leases/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!good) {
                close_nointr(fd);
                return -EINVAL;
        }

        *m = FD_TO_MONITOR(fd);
        return 0;
}

_public_ sd_network_monitor* sd_network_monitor_unref(sd_network_monitor *m) {
        int fd;

        assert_return(m, NULL);

        fd = MONITOR_TO_FD(m);
        close_nointr(fd);

        return NULL;
}

_public_ int sd_network_monitor_flush(sd_network_monitor *m) {

        assert_return(m, -EINVAL);

        return flush_fd(MONITOR_TO_FD(m));
}

_public_ int sd_network_monitor_get_fd(sd_network_monitor *m) {

        assert_return(m, -EINVAL);

        return MONITOR_TO_FD(m);
}

_public_ int sd_network_monitor_get_events(sd_network_monitor *m) {

        assert_return(m, -EINVAL);

        /* For now we will only return POLLIN here, since we don't
         * need anything else ever for inotify.  However, let's have
         * this API to keep our options open should we later on need
         * it. */
        return POLLIN;
}

_public_ int sd_network_monitor_get_timeout(sd_network_monitor *m, uint64_t *timeout_usec) {

        assert_return(m, -EINVAL);
        assert_return(timeout_usec, -EINVAL);

        /* For now we will only return (uint64_t) -1, since we don't
         * need any timeout. However, let's have this API to keep our
         * options open should we later on need it. */
        *timeout_usec = (uint64_t) -1;
        return 0;
}