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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2007 - 2013 Red Hat, Inc.
*/
#include "libnm-glib-aux/nm-default-glib.h"
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include "libnm-glib-aux/nm-logging-syslog.h"
#include "nm-dhcp-helper-api.h"
/*****************************************************************************/
#if NM_MORE_LOGGING
#define _NMLOG_ENABLED(level) TRUE
#else
#define _NMLOG_ENABLED(level) ((level) <= LOG_ERR)
#endif
#define _NMLOG(always_enabled, level, ...) \
G_STMT_START \
{ \
if ((always_enabled) || _NMLOG_ENABLED(level)) { \
gint64 _tv; \
\
_tv = g_get_real_time(); \
g_print("nm-dhcp-helper[%ld] %-7s [%" G_GINT64_FORMAT \
".%04d] " _NM_UTILS_MACRO_FIRST(__VA_ARGS__) "\n", \
(long) getpid(), \
nm_utils_syslog_to_str(level), \
(_tv / NM_UTILS_USEC_PER_SEC), \
((int) ((_tv % NM_UTILS_USEC_PER_SEC) / (((gint64) 100)))) \
_NM_UTILS_MACRO_REST(__VA_ARGS__)); \
} \
} \
G_STMT_END
#define _LOGD(...) _NMLOG(TRUE, LOG_INFO, __VA_ARGS__)
#define _LOGI(...) _NMLOG(TRUE, LOG_NOTICE, __VA_ARGS__)
#define _LOGW(...) _NMLOG(TRUE, LOG_WARNING, __VA_ARGS__)
#define _LOGE(...) _NMLOG(TRUE, LOG_ERR, __VA_ARGS__)
#define _LOGd(...) _NMLOG(FALSE, LOG_INFO, __VA_ARGS__)
#define _LOGi(...) _NMLOG(FALSE, LOG_NOTICE, __VA_ARGS__)
#define _LOGw(...) _NMLOG(FALSE, LOG_WARNING, __VA_ARGS__)
/*****************************************************************************/
static GVariant *
build_signal_parameters(void)
{
const char *const *environ_iter;
GVariantBuilder builder;
g_variant_builder_init(&builder, G_VARIANT_TYPE_VARDICT);
/* List environment and format for dbus dict */
for (environ_iter = (const char *const *) environ; *environ_iter; environ_iter++) {
static const char *const ignore_with_prefix_list[] =
{"PATH", "SHLVL", "_", "PWD", "dhc_dbus", NULL};
const char *item = *environ_iter;
gs_free char *name = NULL;
const char *val;
const char *const *p;
val = strchr(item, '=');
if (!val || item == val)
continue;
name = g_strndup(item, val - item);
val += 1;
/* Ignore non-DHCP-related environment variables */
for (p = ignore_with_prefix_list; *p; p++) {
if (strncmp(name, *p, strlen(*p)) == 0)
goto next;
}
if (!g_utf8_validate(name, -1, NULL))
continue;
/* Value passed as a byte array rather than a string, because there are
* no character encoding guarantees with DHCP, and D-Bus requires
* strings to be UTF-8.
*
* Note that we can't use g_variant_new_bytestring() here, because that
* includes the trailing '\0'. (??!?)
*/
g_variant_builder_add(&builder,
"{sv}",
name,
nm_g_variant_new_ay((const guint8 *) val, strlen(val)));
next:;
}
return g_variant_ref_sink(g_variant_new("(a{sv})", &builder));
}
int
main(int argc, char *argv[])
{
gs_unref_object GDBusConnection *connection = NULL;
gs_free_error GError *error = NULL;
gs_free_error GError *error_flush = NULL;
gs_unref_variant GVariant *parameters = NULL;
gs_unref_variant GVariant *result = NULL;
gs_free char *s_err = NULL;
gboolean success;
guint try_count;
gint64 time_start;
gint64 time_end;
gint64 remaining_time;
gboolean IS_IPv4;
const char *reason;
/* Connecting to the unix socket can fail with EAGAIN if there are too
* many pending connections and the server can't accept them in time
* before reaching backlog capacity. Ideally the server should increase
* the backlog length, but GLib doesn't provide a way to change it for a
* GDBus server. Retry for up to 5 seconds in case of failure. */
time_start = g_get_monotonic_time();
time_end = time_start + (5000 * 1000L);
try_count = 0;
reason = getenv("reason");
_LOGi("nm-dhcp-helper: event called: %s", reason);
IS_IPv4 = !NM_IN_STRSET(reason,
"PREINIT6",
"BOUND6",
"RENEW6",
"REBIND6",
"DEPREF6",
"EXPIRE6",
"RELEASE6",
"STOP6");
do_connect:
try_count++;
connection =
g_dbus_connection_new_for_address_sync("unix:path=" NMRUNDIR "/private-dhcp",
G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT,
NULL,
NULL,
&error);
if (!connection) {
if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
remaining_time = time_end - g_get_monotonic_time();
if (remaining_time > 0) {
gint64 interval;
_LOGi("failure to connect: %s (retry %u, waited %lld ms)",
error->message,
try_count,
(long long) (time_end - remaining_time - time_start) / 1000);
interval = NM_CLAMP((gint64) (100L * (1L << NM_MIN(try_count, 31))), 5000, 100000);
g_usleep(NM_MIN(interval, remaining_time));
g_clear_error(&error);
goto do_connect;
}
}
g_dbus_error_strip_remote_error(error);
_LOGE("could not connect to NetworkManager D-Bus socket: %s", error->message);
success = FALSE;
goto out;
}
parameters = build_signal_parameters();
time_end = g_get_monotonic_time() + (200 * 1000L); /* retry for at most 200 milliseconds */
try_count = 0;
do_notify:
try_count++;
result = g_dbus_connection_call_sync(connection,
NULL,
NM_DHCP_HELPER_SERVER_OBJECT_PATH,
NM_DHCP_HELPER_SERVER_INTERFACE_NAME,
NM_DHCP_HELPER_SERVER_METHOD_NOTIFY,
parameters,
NULL,
G_DBUS_CALL_FLAGS_NONE,
60000,
NULL,
&error);
if (result) {
success = TRUE;
goto out;
}
s_err = g_dbus_error_get_remote_error(error);
if (NM_IN_STRSET(s_err, "org.freedesktop.NetworkManager.Device.Failed")) {
_LOGi("notify failed with reason: %s", error->message);
success = FALSE;
goto out;
}
if (!NM_IN_STRSET(s_err, "org.freedesktop.DBus.Error.UnknownMethod")) {
/* Some unexpected error. We treat that as a failure. In particular,
* the daemon will fail the request if ACD fails. This causes nm-dhcp-helper
* to fail, which in turn causes dhclient to send a DECLINE. */
_LOGW("failure to call notify: %s (try signal via Event)", error->message);
success = FALSE;
goto out;
}
/* I am not sure that a race can actually happen, as we register the object
* on the server side during GDBusServer:new-connection signal.
*
* However, there was also a race for subscribing to an event, so let's just
* do some retry. */
remaining_time = time_end - g_get_monotonic_time();
if (remaining_time > 0) {
gint64 interval;
_LOGi("failure to call notify: %s (retry %u)", error->message, try_count);
interval = NM_CLAMP((gint64) (100L * (1L << NM_MIN(try_count, 31))), 5000, 25000);
g_usleep(NM_MIN(interval, remaining_time));
g_clear_error(&error);
goto do_notify;
}
/* for backward compatibility, try to emit the signal. There is no stable
* API between the dhcp-helper and NetworkManager. However, while upgrading
* the NetworkManager package, a newer helper might want to notify an
* older server, which still uses the "Event". */
_LOGW("failure to call notify: %s (try signal via Event)", error->message);
g_clear_error(&error);
if (g_dbus_connection_emit_signal(connection,
NULL,
"/",
NM_DHCP_CLIENT_DBUS_IFACE,
"Event",
parameters,
&error)) {
/* We were able to send the asynchronous Event. Consider that a success. */
success = TRUE;
goto out;
}
g_dbus_error_strip_remote_error(error);
_LOGE("could not send DHCP Event signal: %s", error->message);
success = FALSE;
out:
if (connection && !g_dbus_connection_flush_sync(connection, NULL, &error_flush)) {
_LOGE("could not flush D-Bus connection: %s", error_flush->message);
/* if we considered this a success so far, don't fail because of this. */
}
_LOGi("success: %s", success ? "YES" : "NO");
/* The error code to send a decline depends on the address family */
return success ? EXIT_SUCCESS : (IS_IPv4 ? 1 : 3);
}
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