diff options
Diffstat (limited to 'ntp_client.c')
| -rw-r--r-- | ntp_client.c | 228 |
1 files changed, 228 insertions, 0 deletions
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); +} |