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dhcp/dhclient: implement accept/decline (ACD) for dhclient plugin

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dhclient itself doesn't do ACD. However, it expects the dhclient-script
to exit with non-zero status, which causes dhclient to send a DECLINE.

`man dhclient-script`:

  BOUND:
     Before actually configuring the address, dhclient-script should
     somehow ARP for it and exit with a nonzero status if it receives a
     reply. In this case, the client will send a DHCPDECLINE  message  to
     the server and acquire a different address.   This may also be done in
     the RENEW, REBIND, or REBOOT states, but is not required, and indeed may
     not be desirable.

See also Fedora's dhclient-script ([1]).

https://gitlab.isc.org/isc-projects/dhcp/-/issues/67#note_97226
33226f2d76/client/dhclient.c (L1652)

[1] a8f6fd046f/f/dhclient-script (_878)

https://bugzilla.redhat.com/show_bug.cgi?id=1713380
This commit is contained in:
Thomas Haller
2022-05-20 21:09:24 +02:00
parent 0f6df633fa
commit 156d84217c
4 changed files with 95 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

103
src/core/dhcp/nm-dhcp-client.c
View File

@@ -50,7 +50,9 @@ typedef struct _NMDhcpClientPrivate {
union {
struct {
int _unused;
struct {
GDBusMethodInvocation *invocation;
} bound;
} v4;
struct {
GSource *lladdr_timeout_source;
@@ -74,7 +76,6 @@ G_DEFINE_ABSTRACT_TYPE(NMDhcpClient, nm_dhcp_client, G_TYPE_OBJECT)
/*****************************************************************************/
static gboolean _dhcp_client_accept(NMDhcpClient *self, const NML3ConfigData *l3cd, GError **error);
static gboolean _dhcp_client_can_accept(NMDhcpClient *self);
_nm_unused static gboolean _dhcp_client_decline(NMDhcpClient *self,
const NML3ConfigData *l3cd,
@@ -419,8 +420,7 @@ _nm_dhcp_client_notify(NMDhcpClient *self,
* as a static address (bypassing ACD), then NML3Cfg is aware of that and signals
* immediate success. */
if (_dhcp_client_can_accept(self) && client_event_type == NM_DHCP_CLIENT_EVENT_TYPE_BOUND
&& priv->l3cd
if (client_event_type == NM_DHCP_CLIENT_EVENT_TYPE_BOUND && priv->l3cd
&& nm_l3_config_data_get_num_addresses(priv->l3cd, priv->config.addr_family) > 0) {
priv->l3cfg_notify.wait_dhcp_commit = TRUE;
} else {
@@ -483,6 +483,25 @@ nm_dhcp_client_stop_watch_child(NMDhcpClient *self, pid_t pid)
watch_cleanup(self);
}
static gboolean
_accept(NMDhcpClient *self, const NML3ConfigData *l3cd, GError **error)
{
NMDhcpClientPrivate *priv = NM_DHCP_CLIENT_GET_PRIVATE(self);
if (!NM_IS_IPv4(priv->config.addr_family))
return TRUE;
if (!priv->v4.bound.invocation) {
nm_utils_error_set(error,
NM_UTILS_ERROR_UNKNOWN,
"calling accept in unexpected script state");
return FALSE;
}
g_dbus_method_invocation_return_value(g_steal_pointer(&priv->v4.bound.invocation), NULL);
return TRUE;
}
static gboolean
_dhcp_client_accept(NMDhcpClient *self, const NML3ConfigData *l3cd, GError **error)
{
@@ -495,27 +514,29 @@ _dhcp_client_accept(NMDhcpClient *self, const NML3ConfigData *l3cd, GError **err
g_return_val_if_fail(NM_DHCP_CLIENT_GET_PRIVATE(self)->l3cd, FALSE);
if (!klass->accept)
return TRUE;
return klass->accept(self, l3cd, error);
}
static gboolean
_dhcp_client_can_accept(NMDhcpClient *self)
decline(NMDhcpClient *self, const NML3ConfigData *l3cd, const char *error_message, GError **error)
{
gboolean can_accept;
NMDhcpClientClass *klass;
NMDhcpClientPrivate *priv = NM_DHCP_CLIENT_GET_PRIVATE(self);
nm_assert(NM_IS_DHCP_CLIENT(self));
if (!NM_IS_IPv4(priv->config.addr_family))
return TRUE;
klass = NM_DHCP_CLIENT_GET_CLASS(self);
if (!priv->v4.bound.invocation) {
nm_utils_error_set(error,
NM_UTILS_ERROR_UNKNOWN,
"calling decline in unexpected script state");
return FALSE;
}
can_accept = !!klass->accept;
nm_assert(can_accept == (!!klass->decline));
return can_accept;
g_dbus_method_invocation_return_error(g_steal_pointer(&priv->v4.bound.invocation),
NM_DEVICE_ERROR,
NM_DEVICE_ERROR_FAILED,
"acd failed");
return TRUE;
}
static gboolean
@@ -533,9 +554,6 @@ _dhcp_client_decline(NMDhcpClient *self,
g_return_val_if_fail(NM_DHCP_CLIENT_GET_PRIVATE(self)->l3cd, FALSE);
if (!klass->decline)
return TRUE;
return klass->decline(self, l3cd, error_message, error);
}
@@ -801,6 +819,13 @@ nm_dhcp_client_stop(NMDhcpClient *self, gboolean release)
priv->is_stopped = TRUE;
if (NM_IS_IPv4(priv->config.addr_family) && priv->v4.bound.invocation) {
g_dbus_method_invocation_return_error(g_steal_pointer(&priv->v4.bound.invocation),
NM_DEVICE_ERROR,
NM_DEVICE_ERROR_FAILED,
"dhcp stopping");
}
priv->l3cfg_notify.wait_dhcp_commit = FALSE;
priv->l3cfg_notify.wait_ll_address = FALSE;
l3_cfg_notify_check_connected(self);
@@ -934,12 +959,13 @@ nm_dhcp_client_emit_ipv6_prefix_delegated(NMDhcpClient *self, const NMPlatformIP
}
gboolean
nm_dhcp_client_handle_event(gpointer unused,
const char *iface,
int pid,
GVariant *options,
const char *reason,
NMDhcpClient *self)
nm_dhcp_client_handle_event(gpointer unused,
const char *iface,
int pid,
GVariant *options,
const char *reason,
GDBusMethodInvocation *invocation,
NMDhcpClient *self)
{
NMDhcpClientPrivate *priv;
nm_auto_unref_l3cd_init NML3ConfigData *l3cd = NULL;
@@ -953,6 +979,7 @@ nm_dhcp_client_handle_event(gpointer unused,
g_return_val_if_fail(pid > 0, FALSE);
g_return_val_if_fail(g_variant_is_of_type(options, G_VARIANT_TYPE_VARDICT), FALSE);
g_return_val_if_fail(reason != NULL, FALSE);
g_return_val_if_fail(G_IS_DBUS_METHOD_INVOCATION(invocation), FALSE);
priv = NM_DHCP_CLIENT_GET_PRIVATE(self);
@@ -964,7 +991,7 @@ nm_dhcp_client_handle_event(gpointer unused,
_LOGD("DHCP event (reason: '%s')", reason);
if (NM_IN_STRSET_ASCII_CASE(reason, "preinit"))
return TRUE;
goto out_handled;
if (NM_IN_STRSET_ASCII_CASE(reason, "bound", "bound6", "static"))
client_event_type = NM_DHCP_CLIENT_EVENT_TYPE_BOUND;
@@ -1028,7 +1055,7 @@ nm_dhcp_client_handle_event(gpointer unused,
* of the DHCP client instance. Instead, we just signal the prefix
* to the device. */
nm_dhcp_client_emit_ipv6_prefix_delegated(self, &prefix);
return TRUE;
goto out_handled;
}
if (NM_IN_SET(client_event_type,
@@ -1040,7 +1067,20 @@ nm_dhcp_client_handle_event(gpointer unused,
client_event_type = NM_DHCP_CLIENT_EVENT_TYPE_FAIL;
}
if (priv->v4.bound.invocation)
g_dbus_method_invocation_return_value(g_steal_pointer(&priv->v4.bound.invocation), NULL);
if (NM_IS_IPv4(priv->config.addr_family)
&& NM_IN_SET(client_event_type,
NM_DHCP_CLIENT_EVENT_TYPE_BOUND,
NM_DHCP_CLIENT_EVENT_TYPE_EXTENDED))
priv->v4.bound.invocation = g_steal_pointer(&invocation);
_nm_dhcp_client_notify(self, client_event_type, l3cd);
out_handled:
if (invocation)
g_dbus_method_invocation_return_value(invocation, NULL);
return TRUE;
}
@@ -1185,7 +1225,10 @@ set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *ps
* explicitly initialize the respective union member. */
if (NM_IS_IPv4(priv->config.addr_family)) {
priv->v4 = (typeof(priv->v4)){
._unused = 0,
.bound =
{
.invocation = NULL,
},
};
} else {
priv->v6 = (typeof(priv->v6)){
@@ -1255,6 +1298,8 @@ nm_dhcp_client_class_init(NMDhcpClientClass *client_class)
object_class->dispose = dispose;
object_class->finalize = finalize;
object_class->set_property = set_property;
client_class->accept = _accept;
client_class->decline = decline;
client_class->stop = stop;
client_class->get_duid = get_duid;

13
src/core/dhcp/nm-dhcp-client.h
View File

@@ -261,12 +261,13 @@ void _nm_dhcp_client_notify(NMDhcpClient *self,
NMDhcpClientEventType client_event_type,
const NML3ConfigData *l3cd);
gboolean nm_dhcp_client_handle_event(gpointer unused,
const char *iface,
int pid,
GVariant *options,
const char *reason,
NMDhcpClient *self);
gboolean nm_dhcp_client_handle_event(gpointer unused,
const char *iface,
int pid,
GVariant *options,
const char *reason,
GDBusMethodInvocation *invocation,
NMDhcpClient *self);
void nm_dhcp_client_emit_ipv6_prefix_delegated(NMDhcpClient *self,
const NMPlatformIP6Address *prefix);

19
src/core/dhcp/nm-dhcp-helper.c
View File

@@ -100,21 +100,6 @@ next:;
return g_variant_ref_sink(g_variant_new("(a{sv})", &builder));
}
static void
kill_pid(void)
{
const char *pid_str;
pid_t pid = 0;
pid_str = getenv("pid");
if (pid_str)
pid = strtol(pid_str, NULL, 10);
if (pid) {
_LOGI("a fatal error occurred, kill dhclient instance with pid %d", pid);
kill(pid, SIGTERM);
}
}
int
main(int argc, char *argv[])
{
@@ -180,7 +165,7 @@ do_notify:
parameters,
NULL,
G_DBUS_CALL_FLAGS_NONE,
1000,
60000,
NULL,
&error);
@@ -236,7 +221,5 @@ do_notify:
}
out:
if (!success)
kill_pid();
return success ? EXIT_SUCCESS : EXIT_FAILURE;
}

22
src/core/dhcp/nm-dhcp-listener.c
View File

@@ -128,7 +128,7 @@ get_option(GVariant *options, const char *key)
}
static void
_method_call_handle(NMDhcpListener *self, GVariant *parameters)
_method_call_handle(NMDhcpListener *self, GDBusMethodInvocation *invocation, GVariant *parameters)
{
gs_free char *iface = NULL;
gs_free char *pid_str = NULL;
@@ -142,23 +142,23 @@ _method_call_handle(NMDhcpListener *self, GVariant *parameters)
iface = get_option(options, "interface");
if (iface == NULL) {
_LOGW("dhcp-event: didn't have associated interface.");
return;
goto out;
}
pid_str = get_option(options, "pid");
pid = _nm_utils_ascii_str_to_int64(pid_str, 10, 0, G_MAXINT32, -1);
if (pid == -1) {
_LOGW("dhcp-event: couldn't convert PID '%s' to an integer", pid_str ?: "(null)");
return;
goto out;
}
reason = get_option(options, "reason");
if (reason == NULL) {
_LOGW("dhcp-event: (pid %d) DHCP event didn't have a reason", pid);
return;
goto out;
}
g_signal_emit(self, signals[EVENT], 0, iface, pid, options, reason, &handled);
g_signal_emit(self, signals[EVENT], 0, iface, pid, options, reason, invocation, &handled);
if (!handled) {
if (g_ascii_strcasecmp(reason, "RELEASE") == 0) {
/* Ignore event when the dhcp client gets killed and we receive its last message */
@@ -166,6 +166,10 @@ _method_call_handle(NMDhcpListener *self, GVariant *parameters)
} else
_LOGW("dhcp-event: (pid %d) unhandled DHCP event for interface %s", pid, iface);
}
out:
if (!handled)
g_dbus_method_invocation_return_value(invocation, NULL);
}
static void
@@ -190,8 +194,7 @@ _method_call(GDBusConnection *connection,
return;
}
_method_call_handle(self, parameters);
g_dbus_method_invocation_return_value(invocation, NULL);
_method_call_handle(self, invocation, parameters);
}
static GDBusInterfaceInfo *const interface_info = NM_DEFINE_GDBUS_INTERFACE_INFO(
@@ -311,9 +314,10 @@ nm_dhcp_listener_class_init(NMDhcpListenerClass *listener_class)
NULL,
NULL,
G_TYPE_BOOLEAN, /* listeners return TRUE if handled */
4,
5,
G_TYPE_STRING, /* iface */
G_TYPE_INT, /* pid */
G_TYPE_VARIANT, /* options */
G_TYPE_STRING); /* reason */
G_TYPE_STRING, /* reason */
G_TYPE_DBUS_METHOD_INVOCATION /* invocation*/);
}