wireguard: initialize timekeeping with RTC

This commit fixes the "Invalid handshake initiation" error when the
client restarts.

Fixes genodelabs/genode#4957

repos/dde_linux/lib/mk/wireguard.inc

@@ -4,9 +4,12 @@ LIBS += base net jitterentropy wireguard_lx_inc_dirs
 
 DDE_LINUX_DIR := $(subst /src/include/lx_kit,,$(call select_from_repositories,src/include/lx_kit))
 
+MUSL_TM_DIR = $(call select_from_repositories,src/lib/musl_tm)
+
 INC_DIR += $(REP_DIR)/src/app/wireguard
 INC_DIR += $(DDE_LINUX_DIR)/src/include/virt_linux
 INC_DIR += $(DDE_LINUX_DIR)/src/include
+INC_DIR += $(MUSL_TM_DIR)
 
 ifeq ($(filter-out $(SPECS),x86_64),)
 SPEC_ARCH := x86_64
@@ -17,6 +20,7 @@ endif
 
 INC_DIR += $(DDE_LINUX_DIR)/src/include/spec/$(SPEC_ARCH)
 
+SRC_C += tm_to_secs.c
 
 SRC_CC += arp_cache.cc
 SRC_CC += arp_waiter.cc
@@ -30,5 +34,6 @@ SRC_CC += main.cc
 SRC_CC += nic_connection.cc
 SRC_CC += uplink_connection.cc
 
+vpath tm_to_secs.c $(MUSL_TM_DIR)
 vpath %.cc $(REP_DIR)/src/app/wireguard
 vpath %.cc $(DDE_LINUX_DIR)/src/lib

repos/dde_linux/recipes/src/wireguard/content.mk

@@ -12,6 +12,11 @@ content: $(MIRRORED_FROM_REP_DIR)
 $(MIRRORED_FROM_REP_DIR):
 	$(mirror_from_rep_dir)
 
+content: src/lib/musl_tm
+src/lib/musl_tm:
+	mkdir -p src/lib
+	cp -r $(GENODE_DIR)/repos/libports/$@ $@
+
 content: LICENSE
 LICENSE:
 	( echo "GNU General Public License version 2, see:"; \

repos/dde_linux/recipes/src/wireguard/used_apis

@@ -1,8 +1,9 @@
 base
-os
-nic_session
-uplink_session
-timer_session
 jitterentropy
 net
+nic_session
+os
+rtc_session
+timer_session
+uplink_session
 virt_linux

repos/dde_linux/src/app/wireguard/main.cc

@@ -19,13 +19,18 @@
 #include <base/component.h>
 #include <base/attached_rom_dataspace.h>
 #include <base/session_label.h>
+#include <rtc_session/connection.h>
 #include <timer_session/connection.h>
 
+/* musl-tm includes */
+#include <tm.h>
+
 /* lx-kit includes */
 #include <lx_kit/env.h>
 
 /* lx-emul includes */
 #include <lx_emul/init.h>
+#include <lx_emul/time.h>
 
 /* lx-user includes */
 #include <lx_user/io.h>
@@ -62,10 +67,13 @@ class Wireguard::Main : private Entrypoint::Io_progress_handler,
 			Lx_kit::env().scheduler.execute();
 		}
 
-		void _handle_config() { _config_rom.update(); }
+		void _set_initial_time_only_once();
+		void _handle_config();
 
 		void _handle_nic_ip_config();
 
+		int64_t _rtc_timestamp_to_seconds(Rtc::Timestamp const &ts);
+
 
 		/*****************************
 		 ** Nic_connection_notifier **
@@ -140,6 +148,49 @@ class Wireguard::Main : private Entrypoint::Io_progress_handler,
 };
 
 
+int64_t Wireguard::Main::_rtc_timestamp_to_seconds(Rtc::Timestamp const &ts)
+{
+   tm tm { .tm_sec      = static_cast<int>(ts.second),
+           .tm_min      = static_cast<int>(ts.minute),
+           .tm_hour     = static_cast<int>(ts.hour),
+           .tm_mday     = static_cast<int>(ts.day),
+           .tm_mon      = static_cast<int>(ts.month - 1),
+           .tm_year     = static_cast<int>(ts.year - 1900),
+           .tm_wday     = 0,
+           .tm_yday     = 0,
+           .tm_isdst    = 0,
+           .__tm_gmtoff = 0,
+           .__tm_zone   = 0 };
+
+   return tm_to_secs(&tm);
+}
+
+void Wireguard::Main::_set_initial_time_only_once()
+{
+	static bool time_already_set { false };
+
+	if (!time_already_set) {
+		Rtc::Connection rtc { _env };
+		Rtc::Timestamp const rtc_current_time { rtc.current_time() };
+
+		lx_emul_time_initial(_rtc_timestamp_to_seconds(rtc_current_time));
+		time_already_set = true;
+	}
+}
+
+void Wireguard::Main::_handle_config()
+{
+	_config_rom.update();
+
+	if (!_config_rom.valid()) return;
+
+	if (_config_rom.xml().attribute_value("use_rtc", false) == true) {
+		_set_initial_time_only_once();
+	}
+
+}
+
+
 void Wireguard::Main::_handle_nic_ip_config()
 {
 	if (_nic_connection.ip_config().valid()) {