/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2010 Dan Williams <dcbw@redhat.com>
*/
#include "src/core/nm-default-daemon.h"
#include "nm-dns-dnsmasq.h"
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <linux/if.h>
#include "libnm-glib-aux/nm-dbus-aux.h"
#include "libnm-core-intern/nm-core-internal.h"
#include "libnm-platform/nm-platform.h"
#include "nm-utils.h"
#include "nm-ip4-config.h"
#include "nm-ip6-config.h"
#include "nm-dbus-manager.h"
#include "NetworkManagerUtils.h"
#define PIDFILE NMRUNDIR "/dnsmasq.pid"
#define CONFDIR NMCONFDIR "/dnsmasq.d"
#define DNSMASQ_DBUS_SERVICE "org.freedesktop.NetworkManager.dnsmasq"
#define DNSMASQ_DBUS_PATH "/uk/org/thekelleys/dnsmasq"
#define RATELIMIT_INTERVAL_MSEC 30000
#define RATELIMIT_BURST 5
#define _NMLOG_DOMAIN LOGD_DNS
/*****************************************************************************/
#define _NMLOG(level, ...) __NMLOG_DEFAULT(level, _NMLOG_DOMAIN, "dnsmasq", __VA_ARGS__)
#define WAIT_MSEC_AFTER_SIGTERM 1000
G_STATIC_ASSERT(WAIT_MSEC_AFTER_SIGTERM <= NM_SHUTDOWN_TIMEOUT_MS);
#define WAIT_MSEC_AFTER_SIGKILL 400
G_STATIC_ASSERT(WAIT_MSEC_AFTER_SIGKILL + 100 <= NM_SHUTDOWN_TIMEOUT_MS_WATCHDOG);
typedef void (*GlPidSpawnAsyncNotify)(GCancellable *cancellable,
GPid pid,
const int * p_exit_code,
GError * error,
gpointer notify_user_data);
typedef struct {
NMShutdownWaitObjHandle *shutdown_wait_handle;
guint64 p_start_time;
gint64 started_at;
GPid pid;
bool sigkilled : 1;
} GlPidKillExternalData;
typedef struct {
const char * dm_binary;
GlPidSpawnAsyncNotify notify;
gpointer notify_user_data;
GCancellable * cancellable;
} GlPidSpawnAsyncData;
static struct {
GlPidKillExternalData *kill_external_data;
GlPidSpawnAsyncData *spawn_data;
NMShutdownWaitObjHandle *terminate_handle;
GPid pid;
guint terminate_timeout_id;
guint watch_id;
/* whether the external process (with the pid from PIDFILE) was already killed.
* This only happens once, once we do that, we remember to not do it again.
* The reason is that later one, when we want to kill the process it's a
* child process. So, we wait for the exit code. */
bool kill_external_done : 1;
bool terminate_sigkill : 1;
} gl_pid;
/*****************************************************************************/
static void _gl_pid_spawn_next_step(void);
static void _gl_pid_spawn_cancelled_cb(GCancellable *cancellable, GlPidSpawnAsyncData *sdata);
/*****************************************************************************/
static gboolean
_gl_pid_unlink_pidfile(gboolean do_unlink)
{
int errsv;
if (do_unlink) {
if (unlink(PIDFILE) == 0)
_LOGD("spawn: delete PID file %s", PIDFILE);
else {
errsv = errno;
if (errsv != ENOENT)
_LOGD("spawn: delete PID file %s failed: %s (%d)",
PIDFILE,
nm_strerror_native(errsv),
errsv);
}
}
return TRUE;
}
static gboolean
_gl_pid_kill_external_timeout_cb(gpointer user_data)
{
guint64 p_start_time;
char p_state = '\0';
gint64 now;
p_start_time = nm_utils_get_start_time_for_pid(gl_pid.kill_external_data->pid, &p_state, NULL);
if (p_start_time == 0 || p_start_time != gl_pid.kill_external_data->p_start_time
|| nm_utils_process_state_is_dead(p_state)) {
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s is gone",
gl_pid.kill_external_data->pid,
PIDFILE);
goto process_gone;
}
now = nm_utils_get_monotonic_timestamp_msec();
if (gl_pid.kill_external_data->started_at + WAIT_MSEC_AFTER_SIGTERM < now) {
if (!gl_pid.kill_external_data->sigkilled) {
_LOGD("spawn: send SIGKILL to process %" G_PID_FORMAT " from pidfile %s",
gl_pid.kill_external_data->pid,
PIDFILE);
gl_pid.kill_external_data->sigkilled = TRUE;
kill(gl_pid.kill_external_data->pid, SIGKILL);
} else if (gl_pid.kill_external_data->started_at + WAIT_MSEC_AFTER_SIGTERM
+ WAIT_MSEC_AFTER_SIGKILL
< now) {
_LOGW("spawn: process %" G_PID_FORMAT
" from pidfile %s is still here after trying to kill it. Wait no longer",
gl_pid.kill_external_data->pid,
PIDFILE);
goto process_gone;
}
}
return G_SOURCE_CONTINUE;
process_gone:
nm_shutdown_wait_obj_unregister(gl_pid.kill_external_data->shutdown_wait_handle);
g_slice_free(GlPidKillExternalData, g_steal_pointer(&gl_pid.kill_external_data));
_gl_pid_unlink_pidfile(TRUE);
_gl_pid_spawn_next_step();
return G_SOURCE_REMOVE;
}
static gboolean
_gl_pid_kill_external(void)
{
gs_free char *contents = NULL;
gs_free char *cmdline_contents = NULL;
gs_free_error GError *error = NULL;
gint64 pid64;
GPid pid = 0;
guint64 p_start_time = 0;
char proc_path[256];
gboolean do_kill = FALSE;
char p_state = '\0';
gboolean do_unlink = TRUE;
int errsv;
if (gl_pid.kill_external_done) {
if (gl_pid.kill_external_data) {
_LOGD("spawn: waiting for external process %" G_PID_FORMAT " from pidfile %s quit",
gl_pid.kill_external_data->pid,
PIDFILE);
return FALSE;
}
return TRUE;
}
if (!g_file_get_contents(PIDFILE, &contents, NULL, &error)) {
if (g_error_matches(error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
do_unlink = FALSE;
_LOGD("spawn: failure to read pidfile %s: %s", PIDFILE, error->message);
g_clear_error(&error);
goto handle_kill;
}
pid64 = _nm_utils_ascii_str_to_int64(contents, 10, 2, G_MAXINT64, -1);
if (pid64 == -1 || (pid = (GPid) pid64) != pid64) {
_LOGD("spawn: pidfile %s does not contain a valid process identifier", PIDFILE);
goto handle_kill;
}
G_STATIC_ASSERT_EXPR(sizeof(pid) == sizeof(pid_t));
p_start_time = nm_utils_get_start_time_for_pid(pid, &p_state, NULL);
if (p_start_time == 0) {
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s seems to no longer exist",
pid,
PIDFILE);
goto handle_kill;
}
nm_sprintf_buf(proc_path, "/proc/%" G_PID_FORMAT "/cmdline", pid);
if (!g_file_get_contents(proc_path, &cmdline_contents, NULL, NULL)) {
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s seems to no longer exist",
pid,
PIDFILE);
goto handle_kill;
}
if (!strstr(cmdline_contents, "/dnsmasq")) {
_LOGD("spawn: process %" G_PID_FORMAT
" from pidfile %s seems to no longer to be a dnsmasq process",
pid,
PIDFILE);
goto handle_kill;
}
do_kill = TRUE;
handle_kill:
gl_pid.kill_external_done = TRUE;
if (!do_kill)
return _gl_pid_unlink_pidfile(do_unlink);
if (nm_utils_process_state_is_dead(p_state)) {
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s is already a zombie", pid, PIDFILE);
return _gl_pid_unlink_pidfile(do_unlink);
}
if (kill(pid, SIGTERM) != 0) {
errsv = errno;
if (errsv == ESRCH)
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s no longer exists",
pid,
PIDFILE);
else
_LOGD("spawn: process %" G_PID_FORMAT " from pidfile %s failed with \"%s\" (%d)",
pid,
PIDFILE,
nm_strerror_native(errsv),
errsv);
return _gl_pid_unlink_pidfile(do_unlink);
}
_LOGD("spawn: waiting for process %" G_PID_FORMAT " from pidfile %s to terminate after SIGTERM",
pid,
PIDFILE);
gl_pid.kill_external_data = g_slice_new(GlPidKillExternalData);
*gl_pid.kill_external_data = (GlPidKillExternalData){
.shutdown_wait_handle = nm_shutdown_wait_obj_register_handle_full(
g_strdup_printf("kill-external-dnsmasq-process-%" G_PID_FORMAT, pid),
TRUE),
.started_at = nm_utils_get_monotonic_timestamp_msec(),
.pid = pid,
.p_start_time = p_start_time,
};
g_timeout_add(50, _gl_pid_kill_external_timeout_cb, NULL);
return FALSE;
}
/*****************************************************************************/
static gboolean
_gl_pid_spawn_clear_pid(void)
{
gboolean was_stopping = !!gl_pid.terminate_handle;
gl_pid.pid = 0;
gl_pid.terminate_sigkill = FALSE;
nm_clear_g_source(&gl_pid.watch_id);
nm_clear_g_source(&gl_pid.terminate_timeout_id);
nm_clear_pointer(&gl_pid.terminate_handle, nm_shutdown_wait_obj_unregister);
return was_stopping;
}
static void
_gl_pid_spawn_register_for_termination(void)
{
if (gl_pid.pid > 0 && !gl_pid.terminate_handle) {
/* Create a shutdown handle as a reminder that the currently running process must be terminated
* first. This also happens to block shutdown... */
gl_pid.terminate_handle = nm_shutdown_wait_obj_register_handle_full(
g_strdup_printf("kill-dnsmasq-process-%" G_PID_FORMAT, gl_pid.pid),
TRUE);
}
}
/**
* _gl_pid_spawn_notify:
* @sdata: the notify data. @sdata might be destroyed by the function,
* depending on the other arguments (which indicate whether the
* task is complete).
* @pid: the PID to notify (argument for GlPidSpawnAsyncNotify)
* @p_exit_code: the exit code to notify (argument for GlPidSpawnAsyncNotify)
* @error: error reason to notify (argument for GlPidSpawnAsyncNotify)
*
* The GlPidSpawnAsyncNotify callback passed to _gl_pid_spawn() is used
* for two purposes:
*
* - signal that the dnsmasq process was spawned (or failed to be spawned).
* - signal that the dnsmasq process quit (if it was spawned successfully before).
*
* Depending on the arguments, the callee can see what's the case.
*/
static void
_gl_pid_spawn_notify(GlPidSpawnAsyncData *sdata, GPid pid, const int *p_exit_code, GError *error)
{
gboolean destroy = TRUE;
nm_assert(sdata);
if (error) {
nm_assert(pid == 0);
nm_assert(!p_exit_code);
if (!nm_utils_error_is_cancelled(error))
_LOGD("spawn: dnsmasq failed: %s", error->message);
} else if (p_exit_code) {
/* the only caller already logged about this condition extensively. */
nm_assert(pid > 0);
} else {
nm_assert(pid > 0);
_LOGD("spawn: dnsmasq started with pid %" G_PID_FORMAT, pid);
destroy = FALSE;
}
nm_assert((!!destroy) == (sdata != gl_pid.spawn_data));
if (destroy)
g_signal_handlers_disconnect_by_func(sdata->cancellable, _gl_pid_spawn_cancelled_cb, sdata);
sdata->notify(sdata->cancellable, pid, p_exit_code, error, sdata->notify_user_data);
if (destroy) {
g_clear_object(&sdata->cancellable);
nm_g_slice_free(sdata);
}
}
static void
_gl_pid_spawn_cancelled_cb(GCancellable *cancellable, GlPidSpawnAsyncData *sdata)
{
gs_free_error GError *error = NULL;
if (sdata == gl_pid.spawn_data) {
gl_pid.spawn_data = NULL;
/* When the cancellable gets cancelled, we terminate the current dnsmasq instance
* in the background. The only way for keeping dnsmasq running while unregistering
* the callback is by calling _gl_pid_spawn() without a new callback. */
_gl_pid_spawn_register_for_termination();
} else
nm_assert_not_reached();
if (!g_cancellable_set_error_if_cancelled(cancellable, &error))
nm_assert_not_reached();
_gl_pid_spawn_notify(sdata, 0, NULL, error);
_gl_pid_spawn_next_step();
}
static gboolean
_gl_pid_spawn_terminate_timeout_cb(gpointer user_data)
{
nm_assert(gl_pid.terminate_timeout_id != 0);
nm_assert(gl_pid.pid > 0);
nm_assert(gl_pid.terminate_handle);
nm_assert(gl_pid.watch_id != 0);
gl_pid.terminate_timeout_id = 0;
if (!gl_pid.terminate_sigkill) {
gl_pid.terminate_sigkill = TRUE;
_LOGD("spawn: send SIGKILL signal to dnsmasq process %" G_PID_FORMAT
" as it did not exit yet",
gl_pid.pid);
kill(gl_pid.pid, SIGKILL);
gl_pid.terminate_timeout_id =
g_timeout_add(WAIT_MSEC_AFTER_SIGKILL, _gl_pid_spawn_terminate_timeout_cb, NULL);
} else {
_LOGE("spawn: process %" G_PID_FORMAT " did not exit even after SIGTERM and SIGKILL",
gl_pid.pid);
/* we don't unregister the watch. Just forget about it. We still want to reap the child eventually. */
gl_pid.watch_id = 0;
_gl_pid_spawn_clear_pid();
_gl_pid_spawn_next_step();
}
return G_SOURCE_REMOVE;
}
static void
_gl_pid_spawn_watch_cb(GPid pid, int status, gpointer user_data)
{
int err;
gboolean was_stopping;
nm_assert(pid > 0);
if (WIFEXITED(status)) {
err = WEXITSTATUS(status);
if (err) {
char sbuf[100];
_LOGW("spawn: dnsmasq process %" G_PID_FORMAT " exited with error: %s",
pid,
nm_utils_dnsmasq_status_to_string(err, sbuf, sizeof(sbuf)));
} else
_LOGD("spawn: dnsmasq process %" G_PID_FORMAT " exited normally", pid);
} else if (WIFSTOPPED(status))
_LOGW("spawn: dnsmasq process %" G_PID_FORMAT " stopped unexpectedly with signal %d",
pid,
WSTOPSIG(status));
else if (WIFSIGNALED(status))
_LOGW("spawn: dnsmasq process %" G_PID_FORMAT " died with signal %d",
pid,
WTERMSIG(status));
else
_LOGW("spawn: dnsmasq process %" G_PID_FORMAT " died from an unknown cause (status %d)",
pid,
status);
if (gl_pid.pid != pid) {
/* this can only happen, if we timed out and no longer care about this PID.
* We still kept the watch-id active, to reap the process. Nothing to do. */
return;
}
nm_assert(gl_pid.watch_id != 0);
gl_pid.watch_id = 0;
_gl_pid_unlink_pidfile(TRUE);
was_stopping = _gl_pid_spawn_clear_pid();
if (gl_pid.spawn_data) {
if (was_stopping) {
/* The current process was scheduled to be terminated. That means the pending
* spawn_data is not for that former instance, but for starting a new one.
* This spawn-request is not yet complete, instead it's just about to start. */
} else
_gl_pid_spawn_notify(g_steal_pointer(&gl_pid.spawn_data), pid, &status, NULL);
}
_gl_pid_spawn_next_step();
}
/**
* _gl_pid_spawn_next_step:
*
* The state about a running dnsmasq process is tracked in @gl_pid. There are
* various things that can happen
*
* - user calls _gl_pid_spawn() -- which might terminate an existing run first.
* - user might cancel the GCancellable -- which would abort the spawning or
* kill the current instance.
* - the child process might exit.
*
* In all these cases, we call _gl_pid_spawn_next_step() to check what to do next.
*/
static void
_gl_pid_spawn_next_step(void)
{
gs_free_error GError *error = NULL;
const char * argv[15];
GPid pid = 0;
guint argv_idx;
if (!_gl_pid_kill_external()) {
/* we need to wait to kill the instance from the PID file first. */
return;
}
if (gl_pid.terminate_handle) {
nm_assert(gl_pid.pid > 0);
if (gl_pid.terminate_timeout_id == 0) {
_LOGD("spawn: send SIGTERM signal to process %" G_PID_FORMAT, gl_pid.pid);
gl_pid.terminate_timeout_id =
g_timeout_add(WAIT_MSEC_AFTER_SIGTERM, _gl_pid_spawn_terminate_timeout_cb, NULL);
kill(gl_pid.pid, SIGTERM);
}
/* we can only wait for the process to exit. */
return;
}
if (!gl_pid.spawn_data) {
/* we are not requested to spawn another process. */
nm_assert(gl_pid.pid == 0);
return;
}
if (gl_pid.pid > 0) {
/* the process we desire is already running. All good. */
return;
}
argv_idx = 0;
argv[argv_idx++] = gl_pid.spawn_data->dm_binary;
argv[argv_idx++] = "--no-resolv"; /* Use only commandline */
argv[argv_idx++] = "--keep-in-foreground";
argv[argv_idx++] = "--no-hosts"; /* don't use /etc/hosts to resolve */
argv[argv_idx++] = "--bind-interfaces";
argv[argv_idx++] = "--pid-file=" PIDFILE;
argv[argv_idx++] = "--listen-address=127.0.0.1"; /* Should work for both 4 and 6 */
argv[argv_idx++] = "--cache-size=400";
argv[argv_idx++] = "--clear-on-reload"; /* clear cache when dns server changes */
argv[argv_idx++] = "--conf-file=/dev/null"; /* avoid loading /etc/dnsmasq.conf */
argv[argv_idx++] = "--proxy-dnssec"; /* Allow DNSSEC to pass through */
argv[argv_idx++] = "--enable-dbus=" DNSMASQ_DBUS_SERVICE;
/* dnsmasq exits if the conf dir is not present */
if (g_file_test(CONFDIR, G_FILE_TEST_IS_DIR))
argv[argv_idx++] = "--conf-dir=" CONFDIR;
argv[argv_idx++] = NULL;
nm_assert(argv_idx <= G_N_ELEMENTS(argv));
if (!_LOGD_ENABLED())
_LOGI("starting %s", gl_pid.spawn_data->dm_binary);
else {
gs_free char *cmdline = NULL;
_LOGD("spawn: starting dnsmasq: %s", (cmdline = g_strjoinv(" ", (char **) argv)));
}
if (!g_spawn_async(NULL,
(char **) argv,
NULL,
G_SPAWN_DO_NOT_REAP_CHILD,
nm_utils_setpgid,
NULL,
&pid,
&error)) {
_gl_pid_spawn_notify(g_steal_pointer(&gl_pid.spawn_data), 0, NULL, error);
return;
}
gl_pid.pid = pid;
gl_pid.watch_id = g_child_watch_add(pid, _gl_pid_spawn_watch_cb, NULL);
_gl_pid_spawn_notify(gl_pid.spawn_data, pid, NULL, NULL);
}
/**
* _gl_pid_spawn:
* @dm_binary: the binary name for dnsmasq to spawn. We could
* detect it ad-hoc right when needing it. But that would be
* asynchronously, and if dnsmasq is not in $PATH, we want to
* fail right away (synchronously). Hence, @dm_binary is
* an argument.
* @cancellable: abort the operation. This will invoke the callback
* a last time. Also, if the dnsmasq process is currently running,
* it will be terminated in the background. To unregister a notify
* call without killing the dnsmasq process, call _gl_pid_spawn()
* again with all arguments %NULL.
* @notify: the callback when the process is started successfully
* and when the process terminates.
* @notify_user_data: user-data for callback.
*
* If a dnsmasq process is already running (from a previous call of
* _gl_pid_spawn()), that one will be replaced. Meaning, the other notify
* callback will be invoked with NM_UTILS_ERROR/NM_UTILS_ERROR_CANCELLED_DISPOSING.
* If you the @dm_binary argument, the previously running process will
* also be terminated first, before spawning a new instance.
* However, you may also pass all arguments as %NULL. In that case, the
* previous @notify will be completed (and forgotten), but the dnsmasq
* process will be left running in the background.
*
* So, you can:
*
* - call _gl_pid_spawn() with a @dm_binary argument. The previous
* notify() completes with NM_UTILS_ERROR_CANCELLED_DISPOSING and
* the dnsmasq process gets killed.
* - cancel the GCancellable, in this case the notify() completes
* with G_IO_ERROR_CANCELLED and the dnsmasq process gets killed.
* - call _gl_pid_spawn() with all arguments %NULL. In that case
* the previous notify() completes with NM_UTILS_ERROR_CANCELLED_DISPOSING
* but the dnsmasq process keeps running in the background.
*
* The callback is used in two cases.
* - When spawning the process it will be invoked always exactly once.
* In this case the callback might be invoked synchronously or
* asynchronously.
* This either provides a PID or a failure reason. In case of a
* failure, that's the end and the process is not running.
* - if the process could be spawned, the child process with the
* provided PID gets monitored. When the process exits, the callback
* will be invoked again, with a failure reason. This is always done
* asynchronously.
*/
static void
_gl_pid_spawn(const char * dm_binary,
GCancellable * cancellable,
GlPidSpawnAsyncNotify notify,
gpointer notify_user_data)
{
GlPidSpawnAsyncData *sdata_replace;
sdata_replace = g_steal_pointer(&gl_pid.spawn_data);
if (dm_binary) {
nm_assert(notify);
nm_assert(G_IS_CANCELLABLE(cancellable));
gl_pid.spawn_data = g_slice_new(GlPidSpawnAsyncData);
*gl_pid.spawn_data = (GlPidSpawnAsyncData){
.dm_binary = dm_binary,
.notify = notify,
.notify_user_data = notify_user_data,
.cancellable = g_object_ref(cancellable),
};
g_signal_connect(cancellable,
"cancelled",
G_CALLBACK(_gl_pid_spawn_cancelled_cb),
gl_pid.spawn_data);
/* If dnsmasq is running, we terminate it and start a new instance.
*
* If the user would not provide a new callback, this would mean to fail/abort
* the currently subscribed notification (below). But it would leave the dnsmasq
* instance running in the background.
* This allows the user to say to not care about the current instance
* anymore, but still leave it running.
*
* To kill the dnsmasq process without scheduling a new one, cancel the cancellable
* instead. */
_gl_pid_spawn_register_for_termination();
} else {
nm_assert(!notify);
nm_assert(!cancellable);
nm_assert(!notify_user_data);
}
if (sdata_replace) {
gs_free_error GError *error = NULL;
/* we don't mark the error as G_IO_ERROR/G_IO_ERROR_CANCELLED. That
* is reserved for cancelling the cancellable. However, the current
* request was obsoleted/replaced by a new one, so we fail it with
* NM_UTILS_ERROR/NM_UTILS_ERROR_CANCELLED_DISPOSING. */
nm_utils_error_set_cancelled(&error, TRUE, NULL);
_gl_pid_spawn_notify(sdata_replace, 0, NULL, error);
}
_gl_pid_spawn_next_step();
}
/*****************************************************************************/
typedef struct {
GDBusConnection *dbus_connection;
GVariant *set_server_ex_args;
GCancellable *update_cancellable;
GCancellable *main_cancellable;
char *name_owner;
gint64 burst_start_at;
GPid process_pid;
guint name_owner_changed_id;
guint main_timeout_id;
guint burst_retry_timeout_id;
guint8 burst_count;
bool is_stopped : 1;
} NMDnsDnsmasqPrivate;
struct _NMDnsDnsmasq {
NMDnsPlugin parent;
NMDnsDnsmasqPrivate _priv;
};
struct _NMDnsDnsmasqClass {
NMDnsPluginClass parent;
};
G_DEFINE_TYPE(NMDnsDnsmasq, nm_dns_dnsmasq, NM_TYPE_DNS_PLUGIN)
#define NM_DNS_DNSMASQ_GET_PRIVATE(self) _NM_GET_PRIVATE(self, NMDnsDnsmasq, NM_IS_DNS_DNSMASQ)
/*****************************************************************************/
#undef _NMLOG
#define _NMLOG(level, ...) __NMLOG_DEFAULT_WITH_ADDR(level, _NMLOG_DOMAIN, "dnsmasq", __VA_ARGS__)
/*****************************************************************************/
static gboolean start_dnsmasq(NMDnsDnsmasq *self, gboolean force_start, GError **error);
/*****************************************************************************/
static void
add_dnsmasq_nameserver(NMDnsDnsmasq * self,
GVariantBuilder *servers,
const char * ip,
const char * domain)
{
g_return_if_fail(ip);
_LOGD("adding nameserver '%s'%s%s%s",
ip,
NM_PRINT_FMT_QUOTED(domain, " for domain \"", domain, "\"", ""));
g_variant_builder_open(servers, G_VARIANT_TYPE("as"));
g_variant_builder_add(servers, "s", ip);
if (domain)
g_variant_builder_add(servers, "s", domain);
g_variant_builder_close(servers);
}
#define IP_ADDR_TO_STRING_BUFLEN (NM_UTILS_INET_ADDRSTRLEN + 1 + IFNAMSIZ)
static const char *
ip_addr_to_string(int addr_family, gconstpointer addr, const char *iface, char *out_buf)
{
int n_written;
char buf2[NM_UTILS_INET_ADDRSTRLEN];
const char *separator;
nm_assert_addr_family(addr_family);
nm_assert(addr);
nm_assert(out_buf);
if (addr_family == AF_INET) {
nm_utils_inet_ntop(addr_family, addr, buf2);
separator = "@";
} else {
if (IN6_IS_ADDR_V4MAPPED(addr))
_nm_utils_inet4_ntop(((const struct in6_addr *) addr)->s6_addr32[3], buf2);
else
_nm_utils_inet6_ntop(addr, buf2);
/* Need to scope link-local addresses with %<zone-id>. Before dnsmasq 2.58,
* only '@' was supported as delimiter. Since 2.58, '@' and '%' are
* supported. Due to a bug, since 2.73 only '%' works properly as "server"
* address.
*/
separator = IN6_IS_ADDR_LINKLOCAL(addr) ? "%" : "@";
}
n_written = g_snprintf(out_buf,
IP_ADDR_TO_STRING_BUFLEN,
"%s%s%s",
buf2,
iface ? separator : "",
iface ?: "");
nm_assert(n_written < IP_ADDR_TO_STRING_BUFLEN);
return out_buf;
}
static void
add_global_config(NMDnsDnsmasq * self,
GVariantBuilder * dnsmasq_servers,
const NMGlobalDnsConfig *config)
{
guint i, j;
g_return_if_fail(config);
for (i = 0; i < nm_global_dns_config_get_num_domains(config); i++) {
NMGlobalDnsDomain *domain = nm_global_dns_config_get_domain(config, i);
const char *const *servers = nm_global_dns_domain_get_servers(domain);
const char * name = nm_global_dns_domain_get_name(domain);
g_return_if_fail(name);
for (j = 0; servers && servers[j]; j++) {
if (!strcmp(name, "*"))
add_dnsmasq_nameserver(self, dnsmasq_servers, servers[j], NULL);
else
add_dnsmasq_nameserver(self, dnsmasq_servers, servers[j], name);
}
}
}
static void
add_ip_config(NMDnsDnsmasq *self, GVariantBuilder *servers, const NMDnsConfigIPData *ip_data)
{
NMIPConfig * ip_config = ip_data->ip_config;
gconstpointer addr;
const char * iface, *domain;
char ip_addr_to_string_buf[IP_ADDR_TO_STRING_BUFLEN];
int addr_family;
guint i, j, num;
iface = nm_platform_link_get_name(NM_PLATFORM_GET, ip_data->data->ifindex);
addr_family = nm_ip_config_get_addr_family(ip_config);
num = nm_ip_config_get_num_nameservers(ip_config);
for (i = 0; i < num; i++) {
addr = nm_ip_config_get_nameserver(ip_config, i);
ip_addr_to_string(addr_family, addr, iface, ip_addr_to_string_buf);
if (!ip_data->domains.has_default_route_explicit && ip_data->domains.has_default_route)
add_dnsmasq_nameserver(self, servers, ip_addr_to_string_buf, NULL);
if (ip_data->domains.search) {
for (j = 0; ip_data->domains.search[j]; j++) {
domain = nm_utils_parse_dns_domain(ip_data->domains.search[j], NULL);
add_dnsmasq_nameserver(self,
servers,
ip_addr_to_string_buf,
domain[0] ? domain : NULL);
}
}
if (ip_data->domains.reverse) {
for (j = 0; ip_data->domains.reverse[j]; j++) {
add_dnsmasq_nameserver(self,
servers,
ip_addr_to_string_buf,
ip_data->domains.reverse[j]);
}
}
}
}
static GVariant *
create_update_args(NMDnsDnsmasq * self,
const NMGlobalDnsConfig *global_config,
const CList * ip_config_lst_head,
const char * hostname)
{
GVariantBuilder servers;
const NMDnsConfigIPData *ip_data;
g_variant_builder_init(&servers, G_VARIANT_TYPE("aas"));
if (global_config)
add_global_config(self, &servers, global_config);
else {
c_list_for_each_entry (ip_data, ip_config_lst_head, ip_config_lst)
add_ip_config(self, &servers, ip_data);
}
return g_variant_new("(aas)", &servers);
}
/*****************************************************************************/
static void
dnsmasq_update_done(GObject *source_object, GAsyncResult *res, gpointer user_data)
{
NMDnsDnsmasq *self;
gs_free_error GError *error = NULL;
gs_unref_variant GVariant *response = NULL;
response = g_dbus_connection_call_finish(G_DBUS_CONNECTION(source_object), res, &error);
if (nm_utils_error_is_cancelled(error))
return;
self = user_data;
if (!response)
_LOGW("dnsmasq update failed: %s", error->message);
else
_LOGD("dnsmasq update successful");
}
static void
send_dnsmasq_update(NMDnsDnsmasq *self)
{
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
if (!priv->name_owner || !priv->set_server_ex_args)
return;
_LOGD("trying to update dnsmasq nameservers");
nm_clear_g_cancellable(&priv->update_cancellable);
priv->update_cancellable = g_cancellable_new();
g_dbus_connection_call(priv->dbus_connection,
priv->name_owner,
DNSMASQ_DBUS_PATH,
DNSMASQ_DBUS_SERVICE,
"SetServersEx",
priv->set_server_ex_args,
NULL,
G_DBUS_CALL_FLAGS_NO_AUTO_START,
20000,
priv->update_cancellable,
dnsmasq_update_done,
self);
}
/*****************************************************************************/
static void
_main_cleanup(NMDnsDnsmasq *self, gboolean emit_failed)
{
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
if (!priv->main_cancellable)
return;
priv->process_pid = 0;
nm_clear_g_free(&priv->name_owner);
nm_clear_g_dbus_connection_signal(priv->dbus_connection, &priv->name_owner_changed_id);
nm_clear_g_source(&priv->main_timeout_id);
nm_clear_g_cancellable(&priv->update_cancellable);
/* cancelling the main_cancellable will also cause _gl_pid_spawn*() to terminate the
* process in the background. */
nm_clear_g_cancellable(&priv->main_cancellable);
if (!priv->is_stopped && priv->burst_retry_timeout_id == 0) {
start_dnsmasq(self, FALSE, NULL);
send_dnsmasq_update(self);
}
}
static void
name_owner_changed(NMDnsDnsmasq *self, const char *name_owner)
{
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
name_owner = nm_str_not_empty(name_owner);
if (nm_streq0(priv->name_owner, name_owner))
return;
g_free(priv->name_owner);
priv->name_owner = g_strdup(name_owner);
if (!name_owner) {
_LOGT("D-Bus name for dnsmasq disappeared");
_main_cleanup(self, TRUE);
return;
}
_LOGT("D-Bus name for dnsmasq got owner %s", name_owner);
nm_clear_g_source(&priv->main_timeout_id);
send_dnsmasq_update(self);
}
static void
name_owner_changed_cb(GDBusConnection *connection,
const char * sender_name,
const char * object_path,
const char * interface_name,
const char * signal_name,
GVariant * parameters,
gpointer user_data)
{
NMDnsDnsmasq *self = user_data;
const char * new_owner;
if (!g_variant_is_of_type(parameters, G_VARIANT_TYPE("(sss)")))
return;
g_variant_get(parameters, "(&s&s&s)", NULL, NULL, &new_owner);
name_owner_changed(self, new_owner);
}
static void
get_name_owner_cb(const char *name_owner, GError *error, gpointer user_data)
{
if (!name_owner && g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
return;
name_owner_changed(user_data, name_owner);
}
static gboolean
spawn_timeout_cb(gpointer user_data)
{
NMDnsDnsmasq *self = user_data;
_LOGW("timeout waiting for dnsmasq to appear on D-Bus");
_main_cleanup(self, TRUE);
return G_SOURCE_REMOVE;
}
static void
spawn_notify(GCancellable *cancellable,
GPid pid,
const int * p_exit_code,
GError * error,
gpointer notify_user_data)
{
NMDnsDnsmasq * self;
NMDnsDnsmasqPrivate *priv;
if (nm_utils_error_is_cancelled(error))
return;
self = notify_user_data;
priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
if (error || p_exit_code) {
_main_cleanup(self, TRUE);
return;
}
nm_assert(pid > 0);
priv->process_pid = pid;
priv->name_owner_changed_id =
nm_dbus_connection_signal_subscribe_name_owner_changed(priv->dbus_connection,
DNSMASQ_DBUS_SERVICE,
name_owner_changed_cb,
self,
NULL);
nm_dbus_connection_call_get_name_owner(priv->dbus_connection,
DNSMASQ_DBUS_SERVICE,
-1,
priv->main_cancellable,
get_name_owner_cb,
self);
}
static gboolean
_burst_retry_timeout_cb(gpointer user_data)
{
NMDnsDnsmasq * self = user_data;
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
priv->burst_retry_timeout_id = 0;
start_dnsmasq(self, TRUE, NULL);
send_dnsmasq_update(self);
return G_SOURCE_REMOVE;
}
static gboolean
start_dnsmasq(NMDnsDnsmasq *self, gboolean force_start, GError **error)
{
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
const char * dm_binary;
gint64 now;
if (G_LIKELY(priv->main_cancellable)) {
/* The process is already running or about to be started. Nothing to do. */
return TRUE;
}
dm_binary = nm_utils_find_helper("dnsmasq", DNSMASQ_PATH, NULL);
if (!dm_binary) {
/* We resolve the binary name before trying to start it asynchronously.
* The reason is, that if dnsmasq is not installed, we want to fail early,
* so that NMDnsManager can fallback to a non-caching implementation. */
nm_utils_error_set(error, NM_UTILS_ERROR_UNKNOWN, "could not find dnsmasq binary");
return FALSE;
}
if (!priv->dbus_connection) {
priv->dbus_connection = nm_g_object_ref(NM_MAIN_DBUS_CONNECTION_GET);
if (!priv->dbus_connection) {
nm_utils_error_set(error,
NM_UTILS_ERROR_UNKNOWN,
"no D-Bus connection available to talk to dnsmasq");
return FALSE;
}
}
now = nm_utils_get_monotonic_timestamp_msec();
if (force_start || priv->burst_start_at == 0
|| priv->burst_start_at + RATELIMIT_INTERVAL_MSEC <= now) {
priv->burst_start_at = now;
priv->burst_count = 1;
nm_clear_g_source(&priv->burst_retry_timeout_id);
_LOGT("rate-limit: start burst interval of %d seconds %s",
RATELIMIT_INTERVAL_MSEC / 1000,
force_start ? " (force)" : "");
} else if (priv->burst_count < RATELIMIT_BURST) {
nm_assert(priv->burst_retry_timeout_id == 0);
priv->burst_count++;
_LOGT("rate-limit: %u try within burst interval of %d seconds",
(guint) priv->burst_count,
RATELIMIT_INTERVAL_MSEC / 1000);
} else {
if (priv->burst_retry_timeout_id == 0) {
_LOGW("dnsmasq dies and gets respawned too quickly. Back off. Something is very wrong");
priv->burst_retry_timeout_id =
g_timeout_add_seconds((2 * RATELIMIT_INTERVAL_MSEC) / 1000,
_burst_retry_timeout_cb,
self);
} else
_LOGT("rate-limit: currently rate-limited from restart");
return TRUE;
}
priv->main_timeout_id = g_timeout_add(10000, spawn_timeout_cb, self);
priv->main_cancellable = g_cancellable_new();
_gl_pid_spawn(dm_binary, priv->main_cancellable, spawn_notify, self);
return TRUE;
}
static gboolean
update(NMDnsPlugin * plugin,
const NMGlobalDnsConfig *global_config,
const CList * ip_config_lst_head,
const char * hostname,
GError ** error)
{
NMDnsDnsmasq * self = NM_DNS_DNSMASQ(plugin);
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
if (!start_dnsmasq(self, TRUE, error))
return FALSE;
nm_clear_pointer(&priv->set_server_ex_args, g_variant_unref);
priv->set_server_ex_args =
g_variant_ref_sink(create_update_args(self, global_config, ip_config_lst_head, hostname));
send_dnsmasq_update(self);
return TRUE;
}
/*****************************************************************************/
static void
stop(NMDnsPlugin *plugin)
{
NMDnsDnsmasq * self = NM_DNS_DNSMASQ(plugin);
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
priv->is_stopped = TRUE;
priv->burst_start_at = 0;
nm_clear_g_source(&priv->burst_retry_timeout_id);
/* Cancelling the cancellable will also terminate the
* process (in the background). */
_main_cleanup(self, FALSE);
}
/*****************************************************************************/
static void
nm_dns_dnsmasq_init(NMDnsDnsmasq *self)
{}
NMDnsPlugin *
nm_dns_dnsmasq_new(void)
{
return g_object_new(NM_TYPE_DNS_DNSMASQ, NULL);
}
static void
dispose(GObject *object)
{
NMDnsDnsmasq * self = NM_DNS_DNSMASQ(object);
NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE(self);
priv->is_stopped = TRUE;
nm_clear_g_source(&priv->burst_retry_timeout_id);
_main_cleanup(self, FALSE);
nm_clear_pointer(&priv->set_server_ex_args, g_variant_unref);
G_OBJECT_CLASS(nm_dns_dnsmasq_parent_class)->dispose(object);
g_clear_object(&priv->dbus_connection);
}
static void
nm_dns_dnsmasq_class_init(NMDnsDnsmasqClass *dns_class)
{
NMDnsPluginClass *plugin_class = NM_DNS_PLUGIN_CLASS(dns_class);
GObjectClass * object_class = G_OBJECT_CLASS(dns_class);
object_class->dispose = dispose;
plugin_class->plugin_name = "dnsmasq";
plugin_class->is_caching = TRUE;
plugin_class->stop = stop;
plugin_class->update = update;
}