From 9e517fde00cd4d891cb96949b3d2f1cce17899ea Mon Sep 17 00:00:00 2001
From: Alexander Alashkin <alexander.alashkin@cesanta.com>
Date: Thu, 24 Nov 2016 09:46:40 +0000
Subject: [PATCH] Implement SNTP client
PUBLISHED_FROM=ac54bcbc81a9ee688e8b90e261172be76a9fbacd
---
examples/sntp_client/Makefile | 3 +
examples/sntp_client/sntp_client.c | 51 +++++
mongoose.c | 292 +++++++++++++++++++++++++++++
mongoose.h | 60 ++++++
4 files changed, 406 insertions(+)
create mode 100644 examples/sntp_client/Makefile
create mode 100644 examples/sntp_client/sntp_client.c
diff --git a/examples/sntp_client/Makefile b/examples/sntp_client/Makefile
new file mode 100644
index 000000000..9dedb8696
--- /dev/null
+++ b/examples/sntp_client/Makefile
@@ -0,0 +1,3 @@
+PROG = sntp_client
+MODULE_CFLAGS = -DMG_ENABLE_SNTP
+include ../examples.mk
diff --git a/examples/sntp_client/sntp_client.c b/examples/sntp_client/sntp_client.c
new file mode 100644
index 000000000..6e1468aa3
--- /dev/null
+++ b/examples/sntp_client/sntp_client.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2016 Cesanta Software Limited
+ * All rights reserved
+ */
+
+#include "mongoose.h"
+
+static int s_exit_flag = 0;
+static const char *s_default_server = "pool.ntp.org";
+
+static void ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+ struct mg_sntp_message *sm = (struct mg_sntp_message *) ev_data;
+ time_t t;
+ (void) c;
+
+ switch (ev) {
+ case MG_SNTP_REPLY:
+ t = time(NULL);
+ fprintf(stdout, "Local time: %s", ctime(&t));
+ t = (time_t) sm->time;
+ fprintf(stdout, "Time from %s: %s", s_default_server, ctime(&t));
+ s_exit_flag = 1;
+ break;
+ case MG_SNTP_FAILED:
+ fprintf(stderr, "Failed to get time\n");
+ s_exit_flag = 1;
+ break;
+ }
+}
+
+int main() {
+ struct mg_mgr mgr;
+ struct mg_connection *c;
+
+ mg_mgr_init(&mgr, NULL);
+
+ c = mg_sntp_get_time(&mgr, ev_handler, s_default_server);
+
+ if (c == NULL) {
+ fprintf(stderr, "Failed to connect to %s\n", s_default_server);
+ return -1;
+ }
+
+ while (s_exit_flag == 0) {
+ mg_mgr_poll(&mgr, 1000);
+ }
+
+ mg_mgr_free(&mgr);
+
+ return 0;
+}
diff --git a/mongoose.c b/mongoose.c
index e5ba8322c..b4d13ca95 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -165,6 +165,16 @@ MG_INTERNAL int mg_get_errno(void);
MG_INTERNAL void mg_close_conn(struct mg_connection *conn);
+MG_INTERNAL int mg_http_common_url_parse(const char *url, const char *schema,
+ const char *schema_tls, int *use_ssl,
+ char **user, char **pass, char **addr,
+ int *port_i, const char **path);
+
+#if MG_ENABLE_SNTP
+MG_INTERNAL int mg_sntp_parse_reply(const char *buf, int len,
+ struct mg_sntp_message *msg);
+#endif
+
#endif /* CS_MONGOOSE_SRC_INTERNAL_H_ */
#ifdef MG_MODULE_LINES
#line 1 "common/cs_dbg.h"
@@ -11463,6 +11473,288 @@ void mg_tun_send_frame(struct mg_connection *ws, uint32_t stream_id,
#endif /* MG_ENABLE_TUN */
#ifdef MG_MODULE_LINES
+#line 1 "mongoose/src/sntp.c"
+#endif
+/*
+ * Copyright (c) 2016 Cesanta Software Limited
+ * All rights reserved
+ */
+
+/* Amalgamated: #include "mongoose/src/internal.h" */
+/* Amalgamated: #include "mongoose/src/sntp.h" */
+/* Amalgamated: #include "mongoose/src/util.h" */
+
+#if MG_ENABLE_SNTP
+
+#define SNTP_TIME_OFFSET 2208988800
+
+#ifndef SNTP_TIMEOUT
+#define SNTP_TIMEOUT 10
+#endif
+
+#ifndef SNTP_ATTEMPTS
+#define SNTP_ATTEMPTS 3
+#endif
+
+static uint64_t mg_get_sec(uint64_t val) {
+ return (val & 0xFFFFFFFF00000000) >> 32;
+}
+
+static uint64_t mg_get_usec(uint64_t val) {
+ uint64_t tmp = (val & 0x00000000FFFFFFFF);
+ tmp *= 1000000;
+ tmp >>= 32;
+ return tmp;
+}
+
+static void mg_ntp_to_tv(uint64_t val, struct timeval *tv) {
+ uint64_t tmp;
+ tmp = mg_get_sec(val);
+ tmp -= SNTP_TIME_OFFSET;
+ tv->tv_sec = tmp;
+ tv->tv_usec = mg_get_usec(val);
+}
+
+static void mg_get_ntp_ts(const char *ntp, uint64_t *val) {
+ uint32_t tmp;
+ memcpy(&tmp, ntp, sizeof(tmp));
+ tmp = ntohl(tmp);
+ *val = (uint64_t) tmp << 32;
+ memcpy(&tmp, ntp + 4, sizeof(tmp));
+ tmp = ntohl(tmp);
+ *val |= tmp;
+}
+
+void mg_sntp_send_request(struct mg_connection *c) {
+ char buf[48] = {0};
+ /*
+ * header - 8 bit:
+ * LI (2 bit) - 3 (not in sync), VN (3 bit) - 4 (version),
+ * mode (3 bit) - 3 (client)
+ */
+ buf[0] = (3 << 6) | (4 << 3) | 3;
+
+/*
+ * Next fields should be empty in client request
+ * stratum, 8 bit
+ * poll interval, 8 bit
+ * rrecision, 8 bit
+ * root delay, 32 bit
+ * root dispersion, 32 bit
+ * ref id, 32 bit
+ * ref timestamp, 64 bit
+ * originate Timestamp, 64 bit
+ * receive Timestamp, 64 bit
+*/
+
+/*
+ * convert time to sntp format (sntp starts from 00:00:00 01.01.1900)
+ * according to rfc868 it is 2208988800L sec
+ * this information is used to correct roundtrip delay
+ * but if local clock is absolutely broken (and doesn't work even
+ * as simple timer), it is better to disable it
+*/
+#ifndef MG_SNMP_NO_DELAY_CORRECTION
+ uint32_t sec;
+ sec = htonl(mg_time() + SNTP_TIME_OFFSET);
+ memcpy(&buf[40], &sec, sizeof(sec));
+#endif
+
+ mg_send(c, buf, sizeof(buf));
+}
+
+#ifndef MG_SNMP_NO_DELAY_CORRECTION
+static uint64_t mg_calculate_delay(uint64_t t1, uint64_t t2, uint64_t t3) {
+ /* roundloop delay = (T4 - T1) - (T3 - T2) */
+ uint64_t d1 = ((mg_time() + SNTP_TIME_OFFSET) * 1000000) -
+ (mg_get_sec(t1) * 1000000 + mg_get_usec(t1));
+ uint64_t d2 = (mg_get_sec(t3) * 1000000 + mg_get_usec(t3)) -
+ (mg_get_sec(t2) * 1000000 + mg_get_usec(t2));
+
+ return (d1 > d2) ? d1 - d2 : 0;
+}
+#endif
+
+MG_INTERNAL int mg_sntp_parse_reply(const char *buf, int len,
+ struct mg_sntp_message *msg) {
+ uint8_t hdr;
+ uint64_t orig_ts_T1, recv_ts_T2, trsm_ts_T3, delay = 0;
+ int mode;
+ struct timeval tv;
+
+ (void) orig_ts_T1;
+ (void) recv_ts_T2;
+ if (len < 48) {
+ return -1;
+ }
+
+ hdr = buf[0];
+
+ if ((hdr & 0x38) >> 3 != 4) {
+ /* Wrong version */
+ return -1;
+ }
+
+ mode = hdr & 0x7;
+ if (mode != 4 && mode != 5) {
+ /* Not a server reply */
+ return -1;
+ }
+
+ memset(msg, 0, sizeof(*msg));
+
+ msg->kiss_of_death = (buf[1] == 0); /* Server asks to not send requests */
+
+ mg_get_ntp_ts(&buf[40], &trsm_ts_T3);
+
+#ifndef MG_SNMP_NO_DELAY_CORRECTION
+ mg_get_ntp_ts(&buf[24], &orig_ts_T1);
+ mg_get_ntp_ts(&buf[32], &recv_ts_T2);
+ delay = mg_calculate_delay(orig_ts_T1, recv_ts_T2, trsm_ts_T3);
+#endif
+
+ mg_ntp_to_tv(trsm_ts_T3, &tv);
+
+ msg->time = (double) tv.tv_sec + (((double) tv.tv_usec + delay) / 1000000.0);
+
+ return 0;
+}
+
+static void mg_sntp_handler(struct mg_connection *c, int ev, void *ev_data) {
+ struct mbuf *io = &c->recv_mbuf;
+ struct mg_sntp_message msg;
+
+ c->handler(c, ev, ev_data);
+
+ switch (ev) {
+ case MG_EV_RECV: {
+ if (mg_sntp_parse_reply(io->buf, io->len, &msg) < 0) {
+ DBG(("Invalid SNTP packet received (%d)", (int) io->len));
+ c->handler(c, MG_SNTP_MALFORMED_REPLY, NULL);
+ } else {
+ c->handler(c, MG_SNTP_REPLY, (void *) &msg);
+ }
+
+ mbuf_remove(io, io->len);
+ break;
+ }
+ }
+}
+
+int mg_set_protocol_sntp(struct mg_connection *c) {
+ if ((c->flags & MG_F_UDP) == 0) {
+ return -1;
+ }
+
+ c->proto_handler = mg_sntp_handler;
+
+ return 0;
+}
+
+struct mg_connection *mg_sntp_connect(struct mg_mgr *mgr,
+ mg_event_handler_t event_handler,
+ const char *sntp_server_name) {
+ struct mg_connection *c = NULL;
+ char url[100], *p_url = url;
+ const char *proto = "", *port = "", *tmp;
+
+ /* If port is not specified, use default (123) */
+ tmp = strchr(sntp_server_name, ':');
+ if (tmp != NULL && *(tmp + 1) == '/') {
+ tmp = strchr(tmp + 1, ':');
+ }
+
+ if (tmp == NULL) {
+ port = ":123";
+ }
+
+ /* Add udp:// if needed */
+ if (strncmp(sntp_server_name, "udp://", 6) != 0) {
+ proto = "udp://";
+ }
+
+ mg_asprintf(&p_url, sizeof(url), "%s%s%s", proto, sntp_server_name, port);
+
+ c = mg_connect(mgr, p_url, event_handler);
+
+ if (c == NULL) {
+ goto cleanup;
+ }
+
+ mg_set_protocol_sntp(c);
+
+cleanup:
+ if (p_url != url) {
+ MG_FREE(p_url);
+ }
+
+ return c;
+}
+
+struct sntp_data {
+ mg_event_handler_t hander;
+ int count;
+};
+
+static void mg_sntp_util_ev_handler(struct mg_connection *c, int ev,
+ void *ev_data) {
+ struct sntp_data *sd = (struct sntp_data *) c->user_data;
+
+ switch (ev) {
+ case MG_EV_CONNECT:
+ if (*(int *) ev_data != 0) {
+ mg_call(c, sd->hander, MG_SNTP_FAILED, NULL);
+ break;
+ }
+ /* fallthrough */
+ case MG_EV_TIMER:
+ if (sd->count <= SNTP_ATTEMPTS) {
+ mg_sntp_send_request(c);
+ mg_set_timer(c, mg_time() + 10);
+ sd->count++;
+ } else {
+ mg_call(c, sd->hander, MG_SNTP_FAILED, NULL);
+ c->flags |= MG_F_CLOSE_IMMEDIATELY;
+ }
+ break;
+ case MG_SNTP_MALFORMED_REPLY:
+ mg_call(c, sd->hander, MG_SNTP_FAILED, NULL);
+ c->flags |= MG_F_CLOSE_IMMEDIATELY;
+ break;
+ case MG_SNTP_REPLY:
+ mg_call(c, sd->hander, MG_SNTP_REPLY, ev_data);
+ c->flags |= MG_F_CLOSE_IMMEDIATELY;
+ break;
+ case MG_EV_CLOSE:
+ MG_FREE(c->user_data);
+ c->user_data = NULL;
+ break;
+ }
+}
+
+struct mg_connection *mg_sntp_get_time(struct mg_mgr *mgr,
+ mg_event_handler_t event_handler,
+ const char *sntp_server_name) {
+ struct mg_connection *c;
+ struct sntp_data *sd = (struct sntp_data *) MG_CALLOC(1, sizeof(*sd));
+ if (sd == NULL) {
+ return NULL;
+ }
+
+ c = mg_sntp_connect(mgr, mg_sntp_util_ev_handler, sntp_server_name);
+ if (c == NULL) {
+ MG_FREE(sd);
+ return NULL;
+ }
+
+ sd->hander = event_handler;
+ c->user_data = sd;
+
+ return c;
+}
+
+#endif /* MG_ENABLE_SNTP */
+#ifdef MG_MODULE_LINES
#line 1 "common/platforms/cc3200/cc3200_libc.c"
#endif
/*
diff --git a/mongoose.h b/mongoose.h
index f7499fbb7..405905ae1 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -2812,6 +2812,10 @@ struct { \
#define MG_ENABLE_TUN MG_ENABLE_HTTP_WEBSOCKET
#endif
+#ifndef MG_ENABLE_SNTP
+#define MG_ENABLE_SNTP 0
+#endif
+
#endif /* CS_MONGOOSE_SRC_FEATURES_H_ */
#ifdef MG_MODULE_LINES
#line 1 "mongoose/src/net_if.h"
@@ -5591,3 +5595,59 @@ uint32_t mg_coap_compose(struct mg_coap_message *cm, struct mbuf *io);
#endif /* MG_ENABLE_COAP */
#endif /* CS_MONGOOSE_SRC_COAP_H_ */
+#ifdef MG_MODULE_LINES
+#line 1 "mongoose/src/sntp.h"
+#endif
+/*
+ * Copyright (c) 2016 Cesanta Software Limited
+ * All rights reserved
+ */
+
+#ifndef CS_MONGOOSE_SRC_SNTP_H_
+#define CS_MONGOOSE_SRC_SNTP_H_
+
+#if MG_ENABLE_SNTP
+
+#define MG_SNTP_EVENT_BASE 500
+
+/*
+ * Received reply from time server. Event handler parameter contains
+ * pointer to mg_sntp_message structure
+ */
+#define MG_SNTP_REPLY (MG_SNTP_EVENT_BASE + 1)
+
+/* Received malformed SNTP packet */
+#define MG_SNTP_MALFORMED_REPLY (MG_SNTP_EVENT_BASE + 2)
+
+/* Failed to get time from server (timeout etc) */
+#define MG_SNTP_FAILED (MG_SNTP_EVENT_BASE + 3)
+
+struct mg_sntp_message {
+ /* if server sends this flags, user should not send requests to it */
+ int kiss_of_death;
+ /* usual mg_time */
+ double time;
+};
+
+/* Establishes connection to given sntp server */
+struct mg_connection *mg_sntp_connect(struct mg_mgr *mgr,
+ mg_event_handler_t event_handler,
+ const char *sntp_server_name);
+
+/* Sends time request to given connection */
+void mg_sntp_send_request(struct mg_connection *c);
+
+/*
+ * Helper function
+ * Establishes connection to time server, tries to send request
+ * repeats sending SNTP_ATTEMPTS times every SNTP_TIMEOUT sec
+ * (if needed)
+ * See sntp_client example
+ */
+struct mg_connection *mg_sntp_get_time(struct mg_mgr *mgr,
+ mg_event_handler_t event_handler,
+ const char *sntp_server_name);
+
+#endif
+
+#endif /* CS_MONGOOSE_SRC_SNTP_H_ */
--
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