NTP server code

ddrown · Jun 5, 2020 · ce3a050 · ce3a050
1 parent bfc5824
commit ce3a050
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Showing 20 changed files with 222 additions and 671 deletions.
diff --git a/Inc/NTPServer.h b/Inc/NTPServer.h
@@ -0,0 +1,52 @@
+#pragma once
+
+#define NTP_LEAP_NONE   0
+#define NTP_LEAP_61S    1
+#define NTP_LEAP_59S    2
+#define NTP_LEAP_UNSYNC 3
+#define NTP_VERS_4      4
+#define NTP_VERS_3      3
+#define NTP_MODE_RSVD   0
+#define NTP_MODE_SYMACT 1
+#define NTP_MODE_SYMPAS 2
+#define NTP_MODE_CLIENT 3
+#define NTP_MODE_SERVER 4
+#define NTP_MODE_BROADC 5
+#define NTP_MODE_CTRL   6
+#define NTP_MODE_PRIV   7
+
+extern "C" {
+  struct ntp_packet {
+    uint8_t mode : 3;
+    uint8_t version : 3;
+    uint8_t leap : 2;
+    uint8_t stratum;
+    uint8_t poll;
+    int8_t precision;
+    uint16_t root_delay;
+    uint16_t root_delay_fb;
+    uint16_t dispersion;
+    uint16_t dispersion_fb;
+    uint32_t ident;
+    uint32_t ref_time;
+    uint32_t ref_time_fb;
+    uint32_t org_time;
+    uint32_t org_time_fb;
+    uint32_t recv_time;
+    uint32_t recv_time_fb;
+    uint32_t trans_time;
+    uint32_t trans_time_fb;
+  };
+};
+
+class NTPServer {
+  public:
+    NTPServer();
+    void recv(struct pbuf *request_buf, struct pbuf *response_buf, const struct ip_addr *addr, u16_t port);
+    void setup();
+
+  private:
+    struct udp_pcb *ntp_pcb;
+};
+
+extern NTPServer server;
diff --git a/Inc/adc.h b/Inc/adc.h
diff --git a/Inc/ntp.h b/Inc/ntp.h
@@ -1,8 +1,4 @@
-#ifndef NTP_H
-#define NTP_H
+#pragma once
 
+void TXTimestampCallback(uint32_t TimeStampLow, uint32_t TimeStampHigh);
 void ntp_init();
-void ntp_poll(uint8_t dest);
-void ntp_poll_set(uint8_t active);
-
-#endif // NTP_H
diff --git a/Makefile b/Makefile
@@ -62,9 +62,7 @@ Src/lwip.c \
 Src/ethernetif.c \
 Src/ping.c \
 Src/ptp.c \
-Src/ntp.c \
 Src/int64.c \
-Src/adc.c \
 Src/timer.c \
 Src/jobs.c \
 Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_eth.c \
@@ -115,8 +113,6 @@ Middlewares/Third_Party/LwIP/src/core/ipv6/mld6.c \
 Middlewares/Third_Party/LwIP/src/core/ipv6/nd6.c \
 Middlewares/Third_Party/LwIP/src/apps/mqtt/mqtt.c \
 Middlewares/Third_Party/LwIP/src/apps/sntp/sntp.c \
-Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_adc.c \
-Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_adc_ex.c \
 Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_i2c.c \
 Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_i2c_ex.c
 
@@ -126,7 +122,9 @@ Src/DateTime.cpp \
 Src/GPS.cpp \
 Src/GPSDateTime.cpp \
 Src/timesync.cpp \
-Src/ClockPID.cpp
+Src/ClockPID.cpp \
+Src/ntp.cpp \
+Src/NTPServer.cpp
 
 # ASM sources
 ASM_SOURCES =  \

diff --git a/Middlewares/Third_Party/LwIP/src/include/lwip/pbuf.h b/Middlewares/Third_Party/LwIP/src/include/lwip/pbuf.h
@@ -174,9 +174,14 @@ struct pbuf {
   u16_t ref;
 
   // RX timestamp
-  u32_t timestamp_seconds;
-  u32_t timestamp_subseconds;
+  union {
+    u32_t parts[2];
+    uint64_t whole;
+  } ts;
 };
+// arm is little endian
+#define TS_POS_S 1
+#define TS_POS_SUBS 0
 
 
 /** Helper struct for const-correctness only.

diff --git a/README.md b/README.md
@@ -2,9 +2,9 @@ Hardware: Seeed's Arch Max with STM32F407 + 100M ethernet
 
 Software: built on STM32CubeMX + LwIP
 
-It will poll the NTP servers listed in Src/ntp.c:dests every second and output to the debug serial port (USB J8)
+There's a simple command line interface on the debug serial port (USB J8)
 
-There's a simple command line interface
+It expects a GPS to be connected to PD6 (uart RX) and PA3 (GPS PPS)
 
 Build system is make + arm-none-eabi-gcc
 

diff --git a/Src/NTPServer.cpp b/Src/NTPServer.cpp
@@ -0,0 +1,104 @@
+extern "C" {
+#include "main.h"
+#include "lwip/udp.h"
+#include "ptp.h"
+#include "uart.h"
+};
+
+#include "NTPServer.h"
+
+NTPServer server;
+
+// the values below are in 2^32 fractional second units
+// 12821ns, measured
+#define TX_DELAY 55065
+/*
+ * from DP83848J datasheet, T2.25.5
+ * RXD[1:0] latency from symbol on receive pair = 38 bits
+ * (default elasticisty of 4 bits)
+ */
+#define RX_PHY 1632
+#define TX_PHY 730
+// adjusting from preamble timestamp to trailer timestamp: 752 bits at 100M
+#define RX_TRAILER 32298
+
+void NTPServer::recv(struct pbuf *request_buf, struct pbuf *response_buf, const struct ip_addr *addr, u16_t port) {
+  union {
+    uint32_t parts[2];
+    uint64_t whole;
+  } start_tx;
+
+  // drop too small packets
+  if(request_buf->len < sizeof(struct ntp_packet)) {
+    return;
+  }
+
+  struct ntp_packet *request = (struct ntp_packet *)request_buf->payload;
+  struct ntp_packet *response = (struct ntp_packet *)response_buf->payload;
+
+  if(request->version < 2 || request->version > 4) {
+    return; // unknown version
+  }
+
+  if(request->mode != NTP_MODE_CLIENT) {
+    return; // not a client request
+  }
+
+  response->mode = NTP_MODE_SERVER;
+  response->version = NTP_VERS_4;
+  response->leap = NTP_LEAP_NONE; // TODO: no leap second support
+  response->stratum = 1;
+  if(response->poll < 6) {
+    response->poll = 6;
+  }
+  if(response->poll > 12) {
+    response->poll = 12;
+  }
+  response->precision = -27; // 168MHz
+  response->root_delay = 0; // TODO
+  response->root_delay_fb = 0; // TODO
+  response->dispersion = 0; // TODO
+  response->dispersion_fb = 0; // TODO
+  response->ident = htonl(0x50505300); // "PPS"
+  response->ref_time = htonl(request_buf->ts.parts[TS_POS_S]); // TODO
+  response->ref_time_fb = 0;
+  response->org_time = request->trans_time;
+  response->org_time_fb = request->trans_time_fb;
+
+  request_buf->ts.parts[TS_POS_SUBS] *= 2; // PTP clock runs at 2^31
+  request_buf->ts.whole += RX_TRAILER - RX_PHY;
+  response->recv_time = htonl(request_buf->ts.parts[TS_POS_S]);
+  response->recv_time_fb = htonl(request_buf->ts.parts[TS_POS_SUBS]);
+
+  start_tx.whole = ptp_now();
+  start_tx.whole += TX_DELAY + TX_PHY;
+  response->trans_time = htonl(start_tx.parts[TS_POS_S]);
+  response->trans_time_fb = htonl(start_tx.parts[TS_POS_SUBS]);
+
+  udp_sendto(ntp_pcb, response_buf, addr, port);
+}
+
+extern "C" {
+static void ntp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const struct ip_addr *addr, u16_t port) {
+  UNUSED(arg);
+  UNUSED(pcb);
+  struct pbuf *response = pbuf_alloc(PBUF_IP, sizeof(struct ntp_packet), PBUF_RAM);
+  if(!response) {
+    pbuf_free(p);
+    return;
+  }
+  server.recv(p, response, addr, port);
+  pbuf_free(p);
+  pbuf_free(response);
+}
+};
+
+NTPServer::NTPServer() {
+  ntp_pcb = NULL;
+}
+
+void NTPServer::setup() {
+  ntp_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
+  udp_recv(ntp_pcb, ntp_recv, NULL);
+  udp_bind(ntp_pcb, IP_ANY_TYPE, 123);
+}