Synchronise using NTP

6 files changed, 511 insertions, 39 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index af55c1f..5019c8d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,20 @@ set(CMAKE_CXX_STANDARD 17)
 # Initialize the SDK
 pico_sdk_init()
 
-add_executable(morningtown morningtown.c)
-target_link_libraries(morningtown pico_stdlib hardware_rtc)
+add_executable(morningtown morningtown.c ntp_client.c)
+
+# For verbose debugging, uncomment this line and see ntp_client.h
+#pico_enable_stdio_usb(morningtown ENABLED)
+
+target_link_libraries(morningtown
+                      pico_stdlib
+                      hardware_rtc
+                      pico_cyw43_arch_lwip_threadsafe_background)
+
 pico_add_extra_outputs(morningtown)
+
+target_compile_definitions(morningtown PRIVATE
+                           WIFI_SSID=\"${WIFI_SSID}\"
+                           WIFI_PASSWORD=\"${WIFI_PASSWORD}\")
+
+target_include_directories(morningtown PRIVATE ${CMAKE_CURRENT_LIST_DIR})
diff --git a/compile b/compile
index b00f0bd..6a63079 100755
--- a/compile
+++ b/compile
@@ -4,7 +4,9 @@ export PICO_SDK_PATH=/mnt/datassd/2023/pico/pico-sdk/
 rm -rf build
 mkdir build
 cd build
-cmake ..
+cmake .. -DPICO_BOARD=pico_w \
+         -DWIFI_SSID=MyWifi \
+         -DWIFI_PASSWORD=MyPassword
 cd ..
 make -C build
 
diff --git a/lwipopts.h b/lwipopts.h
new file mode 100644
index 0000000..cae44f7
--- /dev/null
+++ b/lwipopts.h
@@ -0,0 +1,75 @@
+#ifndef _LWIPOPTS_H
+#define _LWIPOPTS_H
+
+#define NO_SYS                      1
+#define LWIP_SOCKET                 0
+#define MEM_LIBC_MALLOC             0
+#define MEM_ALIGNMENT               4
+#define MEM_SIZE                    4000
+#define MEMP_NUM_TCP_SEG            32
+#define MEMP_NUM_ARP_QUEUE          10
+#define PBUF_POOL_SIZE              24
+#define LWIP_ARP                    1
+#define LWIP_ETHERNET               1
+#define LWIP_ICMP                   1
+#define LWIP_RAW                    1
+#define TCP_WND                     (8 * TCP_MSS)
+#define TCP_MSS                     1460
+#define TCP_SND_BUF                 (8 * TCP_MSS)
+#define TCP_SND_QUEUELEN            ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
+#define LWIP_NETIF_STATUS_CALLBACK  1
+#define LWIP_NETIF_LINK_CALLBACK    1
+#define LWIP_NETIF_HOSTNAME         1
+#define LWIP_NETCONN                0
+#define MEM_STATS                   0
+#define SYS_STATS                   0
+#define MEMP_STATS                  0
+#define LINK_STATS                  0
+// #define ETH_PAD_SIZE                2
+#define LWIP_CHKSUM_ALGORITHM       3
+#define LWIP_DHCP                   1
+#define LWIP_IPV4                   1
+#define LWIP_TCP                    1
+#define LWIP_UDP                    1
+#define LWIP_DNS                    1
+#define LWIP_TCP_KEEPALIVE          1
+#define LWIP_NETIF_TX_SINGLE_PBUF   1
+#define DHCP_DOES_ARP_CHECK         0
+#define LWIP_DHCP_DOES_ACD_CHECK    0
+
+#ifndef NDEBUG
+#define LWIP_DEBUG                  1
+#define LWIP_STATS                  1
+#define LWIP_STATS_DISPLAY          1
+#endif
+
+#define ETHARP_DEBUG                LWIP_DBG_OFF
+#define NETIF_DEBUG                 LWIP_DBG_OFF
+#define PBUF_DEBUG                  LWIP_DBG_OFF
+#define API_LIB_DEBUG               LWIP_DBG_OFF
+#define API_MSG_DEBUG               LWIP_DBG_OFF
+#define SOCKETS_DEBUG               LWIP_DBG_OFF
+#define ICMP_DEBUG                  LWIP_DBG_OFF
+#define INET_DEBUG                  LWIP_DBG_OFF
+#define IP_DEBUG                    LWIP_DBG_OFF
+#define IP_REASS_DEBUG              LWIP_DBG_OFF
+#define RAW_DEBUG                   LWIP_DBG_OFF
+#define MEM_DEBUG                   LWIP_DBG_OFF
+#define MEMP_DEBUG                  LWIP_DBG_OFF
+#define SYS_DEBUG                   LWIP_DBG_OFF
+#define TCP_DEBUG                   LWIP_DBG_OFF
+#define TCP_INPUT_DEBUG             LWIP_DBG_OFF
+#define TCP_OUTPUT_DEBUG            LWIP_DBG_OFF
+#define TCP_RTO_DEBUG               LWIP_DBG_OFF
+#define TCP_CWND_DEBUG              LWIP_DBG_OFF
+#define TCP_WND_DEBUG               LWIP_DBG_OFF
+#define TCP_FR_DEBUG                LWIP_DBG_OFF
+#define TCP_QLEN_DEBUG              LWIP_DBG_OFF
+#define TCP_RST_DEBUG               LWIP_DBG_OFF
+#define UDP_DEBUG                   LWIP_DBG_OFF
+#define TCPIP_DEBUG                 LWIP_DBG_OFF
+#define PPP_DEBUG                   LWIP_DBG_OFF
+#define SLIP_DEBUG                  LWIP_DBG_OFF
+#define DHCP_DEBUG                  LWIP_DBG_OFF
+
+#endif
diff --git a/morningtown.c b/morningtown.c
index baa029c..5f26626 100644
--- a/morningtown.c
+++ b/morningtown.c
@@ -1,11 +1,73 @@
+/*
+ * morningtown.c
+ *
+ * Silent alarm clock
+ *
+ * Copyright © 2023 Thomas White <taw@physics.org>
+ *
+ * This file is part of MorningTown
+ *
+ * MorningTown is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * MorningTown is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MorningTown.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
 #include <pico/stdlib.h>
 #include <hardware/rtc.h>
-#include <pico/util/datetime.h>
+#include <pico/cyw43_arch.h>
+
+#include "ntp_client.h"
 
 #define LED_GREEN 21
 #define LED_RED 22
 
-static void alarm_callback()
+int ntp_sent = 0;
+int ntp_ok = 0;
+
+
+static void flash_red(int n)
+{
+	int i;
+
+	gpio_put(LED_GREEN, 0);
+	for ( i=0; i<10; i++ ) {
+		gpio_put(LED_RED, 1);
+		sleep_ms(100);
+		gpio_put(LED_RED, 0);
+		sleep_ms(100);
+	}
+}
+
+
+static void celebrate()
+{
+	int i;
+
+	for ( i=0; i<10; i++ ) {
+		gpio_put(LED_RED, 1);
+		gpio_put(LED_GREEN, 0);
+		sleep_ms(300);
+		gpio_put(LED_RED, 0);
+		gpio_put(LED_GREEN, 1);
+		sleep_ms(300);
+	}
+
+	gpio_put(LED_GREEN, 0);
+	gpio_put(LED_RED, 0);
+}
+
+
+static void check_clock()
 {
 	datetime_t t = {0};
 	rtc_get_datetime(&t);
@@ -23,57 +85,103 @@ static void alarm_callback()
 }
 
 
-static void start_demo()
+static void ntp_callback(int status)
 {
-	int i;
-	for ( i=0; i<10; i++ ) {
-		gpio_put(LED_RED, 1);
-		gpio_put(LED_GREEN, 0);
-		sleep_ms(250);
-		gpio_put(LED_RED, 0);
-		gpio_put(LED_GREEN, 1);
-		sleep_ms(250);
+	switch ( status ) {
+
+		case NTP_DNS_ERROR:
+		flash_red(5);
+		ntp_sent = 0;
+		break;
+
+		case NTP_DNS_NO_ADDR:
+		flash_red(10);
+		ntp_sent = 0;
+		break;
+
+		case NTP_BAD_REPLY:
+		flash_red(15);
+		ntp_sent = 0;
+		break;
+
+		case NTP_TIMEOUT:
+		flash_red(20);
+		ntp_sent = 0;
+		break;
+
+		case NTP_REQUEST_SENT:
+		break;
+
+		case NTP_REPLY_RECEIVED:
+		celebrate();
+		ntp_ok = 1;
+		break;
 	}
 }
 
 
 int main()
 {
+	NTP_T *ntp_state;
+	int last_conn;
+
 	gpio_init(LED_GREEN);
 	gpio_init(LED_RED);
 	gpio_set_dir(LED_GREEN, GPIO_OUT);
 	gpio_set_dir(LED_RED, GPIO_OUT);
 
-	datetime_t t = {
-		.year  = 2023,
-		.month = 2,
-		.day   = 5,
-		.dotw  = 0, /* 0=Sunday */
-		.hour  = 22,
-		.min   = 25,
-		.sec   = 0
-	};
-	rtc_init();
-	rtc_set_datetime(&t);
+	cyw43_arch_init();
+	cyw43_arch_enable_sta_mode();
 
-	/* Prove we're awake, then reset everything */
-	start_demo();
+	stdio_init_all();
+
+	cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
+	gpio_put(LED_RED, 1);
+	gpio_put(LED_GREEN, 1);
+	sleep_ms(2000);
+	cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
 	gpio_put(LED_RED, 0);
 	gpio_put(LED_GREEN, 0);
 
-	datetime_t alarm = {
-		.year  = -1,
-		.month = -1,
-		.day   = -1,
-		.dotw  = -1,
-		.hour  = -1,
-		.min   = -1,
-		.sec   = 0
-	};
-
-	rtc_set_alarm(&alarm, &alarm_callback);
+	rtc_init();
 
+	ntp_state = ntp_init(ntp_callback);
+	last_conn = 10;
 	while (1) {
-		sleep_ms(1000);
+
+		int st = cyw43_wifi_link_status(&cyw43_state, CYW43_ITF_STA);
+		cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN,
+		                    !ntp_ok && (st == CYW43_LINK_JOIN));
+
+		if ( (st != CYW43_LINK_JOIN) && (last_conn > 10) ) {
+			cyw43_arch_wifi_connect_async(WIFI_SSID,
+			                              WIFI_PASSWORD,
+			                              CYW43_AUTH_WPA2_AES_PSK);
+			debug_print("connecting to wifi...\n");
+			last_conn = 0;
+		}
+
+		if ( (st == CYW43_LINK_JOIN) && !ntp_sent ) {
+			ntp_send_request(ntp_state);
+			debug_print("sending NTP request\n");
+			ntp_sent = 1;
+		}
+
+		if ( ntp_ok ) {
+			debug_print("connected OK.  Checking clock..\n");
+			check_clock();
+		}
+
+		ntp_poll(ntp_state);
+
+		debug_print("tick\n");
+
+		last_conn += 1;
+		if ( ntp_ok ) {
+			sleep_ms(10000);
+		} else {
+			sleep_ms(1000);
+		}
+
 	}
 }
diff --git a/ntp_client.c b/ntp_client.c
new file mode 100644
index 0000000..08f7783
--- /dev/null
+++ b/ntp_client.c
@@ -0,0 +1,228 @@
+/*
+ * ntp_client.c
+ *
+ * Copyright © 2023 Thomas White <taw@physics.org>
+ *
+ * This file is part of MorningTown
+ *
+ * Based on pico-examples/pico_w/ntp_client/picow_ntp_client.c
+ * Original license: BSD-3-Clause
+ * Copyright (c) 2022 Raspberry Pi (Trading) Ltd.
+ *
+ * MorningTown is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * MorningTown is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MorningTown.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <string.h>
+#include <time.h>
+
+#include <hardware/rtc.h>
+#include <pico/stdlib.h>
+#include <pico/util/datetime.h>
+#include <pico/cyw43_arch.h>
+
+#include "lwip/dns.h"
+#include "lwip/pbuf.h"
+#include "lwip/udp.h"
+
+#include "ntp_client.h"
+
+
+typedef struct NTP_T_ {
+	ip_addr_t ntp_server_address;
+	bool dns_request_sent;
+	struct udp_pcb *ntp_pcb;
+	alarm_id_t ntp_resend_alarm;
+	void (*callback)(int status);
+	time_t utc;
+	int have_new_reply;
+	int last_status;
+} NTP_T;
+
+
+#define NTP_SERVER "pool.ntp.org"
+#define NTP_MSG_LEN 48
+#define NTP_PORT 123
+#define NTP_DELTA 2208988800 // seconds between 1 Jan 1900 and 1 Jan 1970
+#define NTP_RESEND_TIME (10 * 1000)
+#define UTC_OFFSET_SEC 3600
+
+
+static void ntp_result(NTP_T *state, int status, time_t *result)
+{
+	debug_print("NTP result:\n");
+	state->have_new_reply = 1;
+	state->last_status = status;
+	if (status == NTP_REPLY_RECEIVED && result) {
+
+		state->utc = *result;
+		debug_print("yay!\n");
+
+		if ( state->ntp_resend_alarm > 0 ) {
+			cancel_alarm(state->ntp_resend_alarm);
+			state->ntp_resend_alarm = 0;
+		}
+
+	} else {
+		debug_print("other reply.\n");
+	}
+
+	state->dns_request_sent = false;
+}
+
+
+static void ntp_request(NTP_T *state)
+{
+	debug_print("sending NTP UDP\n");
+	cyw43_arch_lwip_begin();
+	struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, NTP_MSG_LEN, PBUF_RAM);
+	uint8_t *req = (uint8_t *) p->payload;
+	memset(req, 0, NTP_MSG_LEN);
+	req[0] = 0x1b;
+	udp_sendto(state->ntp_pcb, p, &state->ntp_server_address, NTP_PORT);
+	pbuf_free(p);
+	cyw43_arch_lwip_end();
+	state->callback(NTP_REQUEST_SENT);
+}
+
+
+static void ntp_dns_found(const char *hostname,
+                          const ip_addr_t *ipaddr,
+                          void *arg)
+{
+	NTP_T *state = (NTP_T*)arg;
+	if (ipaddr) {
+		debug_print("DNS ok (%i)\n", *ipaddr);
+		state->ntp_server_address = *ipaddr;
+		ntp_request(state);
+	} else {
+		debug_print("NTP failed: DNS no address\n");
+		ntp_result(state, NTP_DNS_NO_ADDR, NULL);
+	}
+}
+
+
+static void ntp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p,
+                     const ip_addr_t *addr, u16_t port)
+{
+	NTP_T *state = (NTP_T*)arg;
+	uint8_t mode = pbuf_get_at(p, 0) & 0x7;
+	uint8_t stratum = pbuf_get_at(p, 1);
+
+	debug_print("got UDP: %i %i\n", addr, state->ntp_server_address);
+	debug_print("port %i len %i mode %i stratum %i\n", port, p->tot_len, mode, stratum);
+
+	if (ip_addr_cmp(addr, &state->ntp_server_address)
+	 && port == NTP_PORT
+	 && p->tot_len == NTP_MSG_LEN
+	 && mode == 0x4 && stratum != 0)
+	{
+		uint8_t seconds_buf[4] = {0};
+		pbuf_copy_partial(p, seconds_buf, sizeof(seconds_buf), 40);
+		uint32_t seconds_since_1900 = seconds_buf[0] << 24
+		                            | seconds_buf[1] << 16
+		                            | seconds_buf[2] << 8
+		                            | seconds_buf[3];
+		uint32_t seconds_since_1970 = seconds_since_1900 - NTP_DELTA;
+		time_t epoch = seconds_since_1970;
+		debug_print("second since 1970 = %i\n", epoch);
+		ntp_result(state, NTP_REPLY_RECEIVED, &epoch);
+	} else {
+		ntp_result(state, NTP_BAD_REPLY, NULL);
+	}
+	pbuf_free(p);
+}
+
+
+static int64_t ntp_failed_handler(alarm_id_t id, void *user_data)
+{
+	NTP_T *state = (NTP_T*)user_data;
+	ntp_result(state, NTP_TIMEOUT, NULL);
+	return 0;
+}
+
+
+NTP_T *ntp_init(void (*reply_func)(int))
+{
+	NTP_T *state = calloc(1, sizeof(NTP_T));
+	if (!state) return NULL;
+
+	state->callback = reply_func;
+	state->have_new_reply = 0;
+
+	state->ntp_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
+	if (!state->ntp_pcb) {
+		free(state);
+		return NULL;
+	}
+	udp_recv(state->ntp_pcb, ntp_recv, state);
+	return state;
+}
+
+
+void ntp_send_request(NTP_T *state)
+{
+	if ( state == NULL ) return;
+
+	cyw43_arch_lwip_begin();
+	int err = dns_gethostbyname(NTP_SERVER,
+	                            &state->ntp_server_address,
+	                            ntp_dns_found,
+	                            state);
+	cyw43_arch_lwip_end();
+
+	state->ntp_resend_alarm = add_alarm_in_ms(NTP_RESEND_TIME,
+	                                          ntp_failed_handler,
+	                                          state,
+	                                          true);
+
+	state->dns_request_sent = true;
+	if ( err == ERR_OK ) {
+		/* Immediate reply -> cached result */
+		ntp_request(state);
+	} else if (err != ERR_INPROGRESS) {
+		/* Error sending DNS request
+		 * (ERR_INPROGRESS means expect a callback) */
+		ntp_result(state, NTP_DNS_ERROR, NULL);
+	}
+}
+
+
+void ntp_poll(NTP_T *state)
+{
+	if ( !state->have_new_reply ) return;
+	state->have_new_reply = 0;
+
+	if ( state->last_status == NTP_REPLY_RECEIVED ) {
+
+		time_t tv = state->utc + UTC_OFFSET_SEC;
+		struct tm *utc = gmtime(&tv);
+		datetime_t t;
+
+		t.year = utc->tm_year + 1900;
+		t.month = utc->tm_mon + 1;
+		t.day = utc->tm_mday;
+		t.dotw = utc->tm_wday;
+		t.hour = utc->tm_hour;
+		t.min = utc->tm_min;
+		t.sec = utc->tm_sec;
+
+		debug_print("time is %i/%i/%i   %i   %i:%i:%i\n",
+		            t.year, t.month, t.day, t.dotw, t.hour, t.min, t.sec);
+
+		rtc_set_datetime(&t);
+
+	}
+	state->callback(state->last_status);
+}
diff --git a/ntp_client.h b/ntp_client.h
new file mode 100644
index 0000000..aedb411
--- /dev/null
+++ b/ntp_client.h
@@ -0,0 +1,45 @@
+/*
+ * ntp_client.h
+ *
+ * Copyright © 2023 Thomas White <taw@physics.org>
+ *
+ * This file is part of MorningTown
+ *
+ * Based on pico-examples/pico_w/ntp_client/picow_ntp_client.c
+ * Original license: BSD-3-Clause
+ * Copyright (c) 2022 Raspberry Pi (Trading) Ltd.
+ *
+ * MorningTown is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * MorningTown is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MorningTown.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+typedef struct NTP_T_ NTP_T;
+
+enum {
+	NTP_DNS_ERROR,
+	NTP_DNS_NO_ADDR,
+	NTP_REQUEST_SENT,
+	NTP_BAD_REPLY,
+	NTP_TIMEOUT,
+	NTP_REPLY_RECEIVED
+};
+
+extern NTP_T *ntp_init(void (*reply_func)(int));
+extern void ntp_send_request(NTP_T *state);
+extern void ntp_poll(NTP_T *state);
+
+/* For verbose debugging, switch the commenting of these two lines.
+ * .. and see CMakeLists.txt */
+static void debug_print(const char *str, ...) {}
+//#define debug_print printf