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

#include <config.h>
#define ___CONFIG_H__

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

#define INET6
#include <pppd/eui64.h>
#include <pppd/ipv6cp.h>

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

#include "nm-dbus-interface.h"

#include "nm-pppd-plugin.h"
#include "nm-ppp-status.h"

int plugin_init(void);

char pppd_version[] = VERSION;

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

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

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

    switch (arg) {
    case PHASE_DEAD:
        ppp_status = NM_PPP_STATUS_DEAD;
        ppp_phase  = "dead";
        break;
    case PHASE_INITIALIZE:
        ppp_status = NM_PPP_STATUS_INITIALIZE;
        ppp_phase  = "initialize";
        break;
    case PHASE_SERIALCONN:
        ppp_status = NM_PPP_STATUS_SERIALCONN;
        ppp_phase  = "serial connection";
        break;
    case PHASE_DORMANT:
        ppp_status = NM_PPP_STATUS_DORMANT;
        ppp_phase  = "dormant";
        break;
    case PHASE_ESTABLISH:
        ppp_status = NM_PPP_STATUS_ESTABLISH;
        ppp_phase  = "establish";
        break;
    case PHASE_AUTHENTICATE:
        ppp_status = NM_PPP_STATUS_AUTHENTICATE;
        ppp_phase  = "authenticate";
        break;
    case PHASE_CALLBACK:
        ppp_status = NM_PPP_STATUS_CALLBACK;
        ppp_phase  = "callback";
        break;
    case PHASE_NETWORK:
        ppp_status = NM_PPP_STATUS_NETWORK;
        ppp_phase  = "network";
        break;
    case PHASE_RUNNING:
        ppp_status = NM_PPP_STATUS_RUNNING;
        ppp_phase  = "running";
        break;
    case PHASE_TERMINATE:
        ppp_status = NM_PPP_STATUS_TERMINATE;
        ppp_phase  = "terminate";
        break;
    case PHASE_DISCONNECT:
        ppp_status = NM_PPP_STATUS_DISCONNECT;
        ppp_phase  = "disconnect";
        break;
    case PHASE_HOLDOFF:
        ppp_status = NM_PPP_STATUS_HOLDOFF;
        ppp_phase  = "holdoff";
        break;
    case PHASE_MASTER:
        ppp_status = NM_PPP_STATUS_MASTER;
        ppp_phase  = "master";
        break;

    default:
        ppp_phase = "unknown";
        break;
    }

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

    if (ppp_status != NM_PPP_STATUS_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(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(ifname, new_name)) {
            g_message("nm-ppp-plugin: interface name changed from '%s' to '%s'", ifname, new_name);
            g_strlcpy(ifname, new_name, IF_NAMESIZE);
        }
    }
}

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

    nm_phasechange(arg);
}

static void
nm_ip_up(void *data, int arg)
{
    ipcp_options    opts      = ipcp_gotoptions[0];
    ipcp_options    peer_opts = ipcp_hisoptions[0];
    GVariantBuilder builder;
    guint32         pppd_made_up_address = htonl(0x0a404040 + ifunit);

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

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

    if (!opts.ouraddr) {
        g_warning("nm-ppp-plugin: didn't receive an internal IP from pppd!");
        nm_phasechange(PHASE_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(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,
            g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32, dns, len, sizeof(guint32)));
    }

    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,
            g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32, wins, len, sizeof(guint32)));
    }

    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 GVariant *
eui64_to_variant(eui64_t eui)
{
    guint64 iid;

    G_STATIC_ASSERT(sizeof(iid) == sizeof(eui));

    memcpy(&iid, &eui, sizeof(eui));
    return g_variant_new_uint64(iid);
}

static void
nm_ip6_up(void *data, int arg)
{
    ipv6cp_options *ho = &ipv6cp_hisoptions[0];
    ipv6cp_options *go = &ipv6cp_gotoptions[0];
    GVariantBuilder builder;

    g_return_if_fail(G_IS_DBUS_CONNECTION(gl.dbus_connection));

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

    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(ifname));
    g_variant_builder_add(&builder, "{sv}", NM_PPP_IP6_CONFIG_OUR_IID, eui64_to_variant(go->ourid));
    g_variant_builder_add(&builder,
                          "{sv}",
                          NM_PPP_IP6_CONFIG_PEER_IID,
                          eui64_to_variant(ho->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, MAXNAMELEN);
    g_strlcpy(password, my_password, 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(PHASE_DEAD);

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

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

static void
add_ip6_notifier(void)
{
    static struct notifier **notifier  = NULL;
    static gsize             load_once = 0;

    if (g_once_init_enter(&load_once)) {
        void *handle = dlopen(NULL, RTLD_NOW | RTLD_GLOBAL);

        if (handle) {
            notifier = dlsym(handle, "ipv6_up_notifier");
            dlclose(handle);
        }
        g_once_init_leave(&load_once, 1);
    }
    if (notifier)
        add_notifier(notifier, nm_ip6_up, NULL);
    else
        g_message("nm-ppp-plugin: no IPV6CP notifier support; IPv6 not available");
}

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(ipparam);

    chap_passwd_hook = get_credentials;
    chap_check_hook  = get_chap_check;
    pap_passwd_hook  = get_credentials;
    pap_check_hook   = get_pap_check;

    add_notifier(&phasechange, nm_phasechange_hook, NULL);
    add_notifier(&ip_up_notifier, nm_ip_up, NULL);
    add_notifier(&exitnotify, nm_exit_notify, NULL);
    add_ip6_notifier();

    return 0;
}