/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2008 Novell, Inc.
 * Copyright (C) 2008 Red Hat, Inc.
 */

#include "libnm-glib-aux/nm-default-glib.h"

#include "nm-pppd-plugin.h"

#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <dlfcn.h>
#include <glib.h>

#include "nm-pppd-compat.h"
#include "nm-ppp-status.h"
#include "nm-dbus-interface.h"

int plugin_init(void);

static struct {
    GDBusConnection *dbus_connection;
    char            *ipparam;
} gl;

static void
nm_phasechange(int arg)
{
    NMPPPStatus ppp_status;
    char       *ppp_phase;

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

    ppp_status = arg;

    switch (arg) {
    case NM_PPP_STATUS_DEAD:
        ppp_phase = "dead";
        break;
    case NM_PPP_STATUS_INITIALIZE:
        ppp_phase = "initialize";
        break;
    case NM_PPP_STATUS_SERIALCONN:
        ppp_phase = "serial connection";
        break;
    case NM_PPP_STATUS_DORMANT:
        ppp_phase = "dormant";
        break;
    case NM_PPP_STATUS_ESTABLISH:
        ppp_phase = "establish";
        break;
    case NM_PPP_STATUS_AUTHENTICATE:
        ppp_phase = "authenticate";
        break;
    case NM_PPP_STATUS_CALLBACK:
        ppp_phase = "callback";
        break;
    case NM_PPP_STATUS_NETWORK:
        ppp_phase = "network";
        break;
    case NM_PPP_STATUS_RUNNING:
        ppp_phase = "running";
        break;
    case NM_PPP_STATUS_TERMINATE:
        ppp_phase = "terminate";
        break;
    case NM_PPP_STATUS_DISCONNECT:
        ppp_phase = "disconnect";
        break;
    case NM_PPP_STATUS_HOLDOFF:
        ppp_phase = "holdoff";
        break;
    case NM_PPP_STATUS_MASTER:
        ppp_phase = "master";
        break;

    default:
        ppp_status = NM_PPP_STATUS_INTERN_UNKNOWN;
        ppp_phase  = "unknown";
        break;
    }

    g_message("nm-ppp-plugin: status %d / phase '%s'", ppp_status, ppp_phase);

    if (ppp_status != NM_PPP_STATUS_INTERN_UNKNOWN) {
        g_dbus_connection_call(gl.dbus_connection,
                               NM_DBUS_SERVICE,
                               gl.ipparam,
                               NM_DBUS_INTERFACE_PPP,
                               "SetState",
                               g_variant_new("(u)", ppp_status),
                               G_VARIANT_TYPE("()"),
                               G_DBUS_CALL_FLAGS_NONE,
                               -1,
                               NULL,
                               NULL,
                               NULL);
    }

    if (ppp_status == NM_PPP_STATUS_RUNNING) {
        gs_unref_variant GVariant *ret = NULL;
        char                       new_name[IF_NAMESIZE];
        int                        ifindex;

        ifindex = if_nametoindex(nm_pppd_compat_get_ifname());

        /* Make a sync call to ensure that when the call
         * terminates the interface already has its final
         * name. */
        ret = g_dbus_connection_call_sync(gl.dbus_connection,
                                          NM_DBUS_SERVICE,
                                          gl.ipparam,
                                          NM_DBUS_INTERFACE_PPP,
                                          "SetIfindex",
                                          g_variant_new("(i)", ifindex),
                                          G_VARIANT_TYPE("()"),
                                          G_DBUS_CALL_FLAGS_NONE,
                                          25000,
                                          NULL,
                                          NULL);

        /* Update the name in pppd if NM changed it */
        if (if_indextoname(ifindex, new_name)
            && !nm_streq0(nm_pppd_compat_get_ifname(), new_name)) {
            g_message("nm-ppp-plugin: interface name changed from '%s' to '%s'",
                      nm_pppd_compat_get_ifname(),
                      new_name);
            nm_pppd_compat_set_ifname(new_name);
        }
    }
}

static void
nm_phasechange_hook(void *data, int arg)
{
    /* We send the nofication in exitnotify instead */
    if (arg == NM_PPP_STATUS_DEAD)
        return;

    nm_phasechange(arg);
}

static void
nm_ip_up(void *data, int arg)
{
    NMPppdCompatIPCPOptions opts;
    NMPppdCompatIPCPOptions peer_opts;
    GVariantBuilder         builder;
    const in_addr_t         pppd_made_up_address =
        htonl(0x0a404040u + ((guint) nm_pppd_compat_get_ifunit()));

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

    g_message("nm-ppp-plugin: ip-up event");

    nm_pppd_compat_get_ipcp_options(&opts, &peer_opts);

    if (!opts.ouraddr) {
        g_warning("nm-ppp-plugin: didn't receive an internal IP from pppd!");
        nm_phasechange(NM_PPP_STATUS_DEAD);
        return;
    }

    g_variant_builder_init(&builder, G_VARIANT_TYPE_VARDICT);

    /* Keep sending the interface name to be backwards compatible
     * with older versions of NM during a package upgrade, where
     * NM is not restarted and the pppd plugin was not loaded. */
    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP4_CONFIG_INTERFACE,
                          g_variant_new_string(nm_pppd_compat_get_ifname()));

    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP4_CONFIG_ADDRESS,
                          g_variant_new_uint32(opts.ouraddr));

    /* Prefer the peer options remote address first, _unless_ pppd made the
     * address up, at which point prefer the local options remote address,
     * and if that's not right, use the made-up address as a last resort.
     */
    if (peer_opts.hisaddr && (peer_opts.hisaddr != pppd_made_up_address)) {
        g_variant_builder_add(&builder,
                              "{sv}",
                              NM_PPP_IP4_CONFIG_GATEWAY,
                              g_variant_new_uint32(peer_opts.hisaddr));
    } else if (opts.hisaddr) {
        g_variant_builder_add(&builder,
                              "{sv}",
                              NM_PPP_IP4_CONFIG_GATEWAY,
                              g_variant_new_uint32(opts.hisaddr));
    } else if (peer_opts.hisaddr == pppd_made_up_address) {
        /* As a last resort, use the made-up address */
        g_variant_builder_add(&builder,
                              "{sv}",
                              NM_PPP_IP4_CONFIG_GATEWAY,
                              g_variant_new_uint32(peer_opts.ouraddr));
    }

    g_variant_builder_add(&builder, "{sv}", NM_PPP_IP4_CONFIG_PREFIX, g_variant_new_uint32(32));

    if (opts.dnsaddr[0] || opts.dnsaddr[1]) {
        guint32 dns[2];
        int     len = 0;

        if (opts.dnsaddr[0])
            dns[len++] = opts.dnsaddr[0];
        if (opts.dnsaddr[1])
            dns[len++] = opts.dnsaddr[1];

        g_variant_builder_add(&builder,
                              "{sv}",
                              NM_PPP_IP4_CONFIG_DNS,
                              nm_g_variant_new_au(dns, len));
    }

    if (opts.winsaddr[0] || opts.winsaddr[1]) {
        guint32 wins[2];
        int     len = 0;

        if (opts.winsaddr[0])
            wins[len++] = opts.winsaddr[0];
        if (opts.winsaddr[1])
            wins[len++] = opts.winsaddr[1];

        g_variant_builder_add(&builder,
                              "{sv}",
                              NM_PPP_IP4_CONFIG_WINS,
                              nm_g_variant_new_au(wins, len));
    }

    g_message("nm-ppp-plugin: sending IPv4 config to NetworkManager...");

    g_dbus_connection_call(gl.dbus_connection,
                           NM_DBUS_SERVICE,
                           gl.ipparam,
                           NM_DBUS_INTERFACE_PPP,
                           "SetIp4Config",
                           g_variant_new("(a{sv})", &builder),
                           G_VARIANT_TYPE("()"),
                           G_DBUS_CALL_FLAGS_NONE,
                           -1,
                           NULL,
                           NULL,
                           NULL);
}

static void
nm_ip6_up(void *data, int arg)
{
    NMPppdCompatIPV6CPOptions his;
    NMPppdCompatIPV6CPOptions got;
    GVariantBuilder           builder;

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

    g_message("nm-ppp-plugin: ip6-up event");

    nm_pppd_compat_get_ipv6cp_options(&got, &his);

    g_variant_builder_init(&builder, G_VARIANT_TYPE_VARDICT);
    /* Keep sending the interface name to be backwards compatible
     * with older versions of NM during a package upgrade, where
     * NM is not restarted and the pppd plugin was not loaded. */
    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP6_CONFIG_INTERFACE,
                          g_variant_new_string(nm_pppd_compat_get_ifname()));
    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP6_CONFIG_OUR_IID,
                          g_variant_new_uint64(got.ourid));
    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP6_CONFIG_PEER_IID,
                          g_variant_new_uint64(his.hisid));

    /* DNS is done via DHCPv6 or router advertisements */

    g_message("nm-ppp-plugin: sending IPv6 config to NetworkManager...");

    g_dbus_connection_call(gl.dbus_connection,
                           NM_DBUS_SERVICE,
                           gl.ipparam,
                           NM_DBUS_INTERFACE_PPP,
                           "SetIp6Config",
                           g_variant_new("(a{sv})", &builder),
                           G_VARIANT_TYPE("()"),
                           G_DBUS_CALL_FLAGS_NONE,
                           -1,
                           NULL,
                           NULL,
                           NULL);
}

static int
get_chap_check(void)
{
    return 1;
}

static int
get_pap_check(void)
{
    return 1;
}

static int
get_credentials(char *username, char *password)
{
    gs_unref_variant GVariant *ret   = NULL;
    gs_free_error GError      *error = NULL;
    const char                *my_username;
    const char                *my_password;

    if (!password) {
        /* pppd is checking pap support; return 1 for supported */
        g_return_val_if_fail(username, -1);
        return 1;
    }

    g_return_val_if_fail(username, -1);
    g_return_val_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection), -1);

    g_message("nm-ppp-plugin: passwd-hook, requesting credentials...");

    ret = g_dbus_connection_call_sync(gl.dbus_connection,
                                      NM_DBUS_SERVICE,
                                      gl.ipparam,
                                      NM_DBUS_INTERFACE_PPP,
                                      "NeedSecrets",
                                      NULL,
                                      G_VARIANT_TYPE("(ss)"),
                                      G_DBUS_CALL_FLAGS_NONE,
                                      -1,
                                      NULL,
                                      &error);
    if (!ret) {
        g_warning("nm-ppp-plugin: could not get secrets: %s", error->message);
        return -1;
    }

    g_message("nm-ppp-plugin: got credentials from NetworkManager");

    g_variant_get(ret, "(&s&s)", &my_username, &my_password);

    g_strlcpy(username, my_username, NM_PPPD_COMPAT_MAXNAMELEN);
    g_strlcpy(password, my_password, NM_PPPD_COMPAT_MAXSECRETLEN);

    return 1;
}

static void
nm_exit_notify(void *data, int arg)
{
    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

    /* We wait until this point to notify dead phase to make sure that
     * the serial port has recovered already its original settings.
     */
    nm_phasechange(NM_PPP_STATUS_DEAD);

    g_message("nm-ppp-plugin: cleaning up");

    g_clear_object(&gl.dbus_connection);
    nm_clear_g_free(&gl.ipparam);
}

int
plugin_init(void)
{
    gs_free_error GError *err = NULL;

    g_message("nm-ppp-plugin: initializing");

    nm_assert(!gl.dbus_connection);
    nm_assert(!gl.ipparam);

    gl.dbus_connection = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, &err);
    if (!gl.dbus_connection) {
        g_warning("nm-pppd-plugin: couldn't connect to system bus: %s", err->message);
        return -1;
    }

    gl.ipparam = g_strdup(nm_pppd_compat_get_ipparam());

    nm_pppd_compat_set_chap_passwd_hook(get_credentials);
    nm_pppd_compat_set_chap_check_hook(get_chap_check);
    nm_pppd_compat_set_pap_passwd_hook(get_credentials);
    nm_pppd_compat_set_pap_check_hook(get_pap_check);

    nm_pppd_compat_add_notify(NM_PPPD_COMPAT_NF_PHASE_CHANGE, nm_phasechange_hook, NULL);
    nm_pppd_compat_add_notify(NM_PPPD_COMPAT_NF_IP_UP, nm_ip_up, NULL);
    nm_pppd_compat_add_notify(NM_PPPD_COMPAT_NF_EXIT, nm_exit_notify, NULL);
    nm_pppd_compat_add_notify(NM_PPPD_COMPAT_NF_IPV6_UP, nm_ip6_up, NULL);
    return 0;
}