red in any case

src/Makefile

@@ -1,17 +1,17 @@
 CC=gcc
 
 CFLAGS=-Wall
-LDFLAGS=-lwiringPi -lcurl -lconfig
+LDFLAGS=-lwiringPi -lconfig
 
 INST_DIR=/opt/sbin
 
-REFCNT:=$(shell git rev-list --all --count) 
+REFCNT := $(shell git rev-list --all --count) 
-VERSION:=$(shell cat VERSION)
+VERSION := $(shell git rev-parse --short=8 HEAD)
 
 .PHONY: all
 all:	counter
 
-counter:	counter.o LS7366R.o influx.o ringbuffer.o led.o logging.o version.o
+counter:	counter.o LS7366R.o ringbuffer.o led.o logging.o sinkSender.o sha256.o version.o
 	$(CC) -o $@ $(LDFLAGS) $^
 
 version.o:	version.c VERSION

src/VERSION

@@ -1 +1 @@
-0.97
+0.98

src/counter.c

@@ -6,12 +6,13 @@
 #include <unistd.h>
 #include <libconfig.h>
 #include <math.h>
+#include <time.h>
 
 #include "LS7366R.h"
-#include "influx.h"
 #include "ringbuffer.h"
 #include "led.h"
 #include "logging.h"
+#include "sinkSender.h"
 
 
 extern char VERSION[];
@@ -22,12 +23,11 @@ const int INTR_IN  = 19;
 const int SPI_CHAN = 0;
 const int SPI_SPEED = 1000000;
 
+const uint32_t PRECISION = 1000;
+const uint32_t COUNTER_FREQUENCY = 1e6;
+
 config_t cfg;
 
-const char EPSILON_KEY[] = "epsilon";
-const double DEFAULT_EPSILON = 0.01;
-
-uint32_t skipped = 0;
 
 
 void isr() {
@@ -69,57 +69,43 @@ void start() {
 }
 
 int main (void) {
-  fprintf(stderr, "VERSION: %s, REFCNT: %u\n", VERSION, REFCNT);
+  logmsg(LOG_INFO, "VERSION: %s, REFCNT: %u\n", VERSION, REFCNT);
 
   readConfig();
   init();
-  ledInit();
+  ledInit(&cfg);
   ls7366rInit(SPI_CHAN);
-  influxInit(&cfg);
+  sinkSenderInit(&cfg);
   start();
 
-  double epsilon;
+  struct timespec timestamp;
-  if (! config_lookup_float(&cfg, EPSILON_KEY, &epsilon)) {
+  uint32_t last_seconds = 0;
-    epsilon = DEFAULT_EPSILON;
+  uint32_t last_milliseconds = 0;
-  }
+  uint32_t mainsCntSum = 0;
-  fprintf(stderr, "CONFIG: epsilon=%f\n", epsilon);
+  uint32_t mainsCntCnt = 0;
-  
-
-  double lastF = 0;
-  bool settled = false;
-  uint8_t ledTick = 0;  
 
   while (1) {
     uint32_t period = ringbufferGet();
   
-    double fRaw = 1.0 / (((double) period) / 1000000.0);
+    clock_gettime(CLOCK_REALTIME, &timestamp);
-    int valid = settled ? 1 : 0;
+    uint32_t current_seconds = timestamp.tv_sec;
+    uint32_t current_milliseconds = timestamp.tv_nsec / 1e6;
+    uint32_t duration = ((current_seconds - last_seconds) * 1000) + (current_milliseconds - last_milliseconds);
 
-    double gradient = fRaw - lastF;
+    mainsCntSum += period;
-    double fSmoothed = fRaw;
+    mainsCntCnt += 1;
-    if (settled && (fabs(gradient) > epsilon)) {
+
-      logmsg(LOG_INFO, "Current f=%f, last f=%f, gradient %f too large, invalid\n", fRaw, lastF, gradient);
+    if (duration >= 1000) {
-      skipped++;
+      last_seconds = current_seconds;
-      fSmoothed = lastF;
+      last_milliseconds = current_milliseconds;
-      valid = 0;
+
-    } else {
+      uint32_t cnt = mainsCntSum / mainsCntCnt;
-      lastF = fRaw;
+      mainsCntSum = 0;
+      mainsCntCnt = 0;
+      uint32_t freq = PRECISION * COUNTER_FREQUENCY / cnt;
+
+      sinkSenderPut(current_seconds, freq);
     }
-
-    if (settled) {
-      influxAddFrequency(period, fRaw, fSmoothed, gradient, valid);
-    }
-
-    ledTick++;
-    if (ledTick == 50) {
-      ledTick = 0;
-      led(E_GREEN, false);
-      if (! settled) {
-        logmsg(LOG_INFO, "Now it is settled\n");
-        settled = true;
-      }
-    }
-
   }
 
   // will never be reached

src/counter.cfg

@@ -1,3 +1,8 @@
-influxUser = "secundus"
+led = "off"
-influxPass = "geheim"
+
-influxUrl = "http://172.16.3.15:8086/write?db=smarthome2&precision=ms"
+sinkServer = "sink.hottis.de"
+sinkPort = 20169
+
+deviceId = "mainscnt03"
+// sharedSecret has to have exactly 31 octets
+sharedSecret = "1234567890123456789012345678901"

src/influx.c

@@ -1,179 +0,0 @@
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <curl/curl.h>
-#include <time.h>
-#include <string.h>
-#include <unistd.h>
-#include <libconfig.h>
-
-#include "led.h"
-#include "logging.h"
-
-
-const char INFLUXURL_KEY[] = "influxUrl";
-const char DEFAULT_INFLUXURL[] = "http://172.16.3.15:8086/write?db=smarthome2&precision=ms";
-const char *influxUrl;
-const char INFLUXUSER_KEY[] = "influxUser";
-const char *influxUser;
-const char INFLUXPASS_KEY[] = "influxPass";
-const char *influxPass;
-const char INFLUXTAG_KEY[] = "influxTag";
-const char *influxTag;
-const char DEFAULT_LOCATION[] = "Essen_DE";
-const char LOCATION_KEY[] = "location";
-const char *location;
-
-const uint8_t ONE_SECOND_DIVIDER = 50;
-
-
-extern uint32_t skipped;
-
-
-// #define BUFSIZE 131070
-#define BUFSIZE 65535
-// #define BUFSIZE 1024
-// char influxBuffer[BUFSIZE];
-// char *bufferNextEntry;
-
-typedef struct influxBuffer {
-    uint32_t entries;
-    uint32_t totalEntries;
-    char *nextEntry;
-    char buffer[BUFSIZE];
-} tInfluxBuffer;
-
-typedef enum {
-    PERIOD_20MS = 0,
-    PERIOD_1S,
-    PERIOD_END
-} ePeriod;
-
-tInfluxBuffer *influxBuffers[PERIOD_END];
-
-#define HOSTNAMESIZE 128
-char hostname[HOSTNAMESIZE];
-
-static void influxClearBuffer(tInfluxBuffer *influxBuffer, bool initial) {
-    memset(influxBuffer->buffer, 0, BUFSIZE);
-    influxBuffer->nextEntry = influxBuffer->buffer;
-    influxBuffer->entries = 0;
-    if (initial) {
-        influxBuffer->totalEntries = 0;
-    }
-
-}
-
-void influxInit(config_t *pCfg) {
-    if (! config_lookup_string(pCfg, INFLUXURL_KEY, &influxUrl)) {
-        influxUrl = DEFAULT_INFLUXURL;
-    }
-    fprintf(stderr, "CONFIG: influxUrl=%s\n", influxUrl);
-    if (! config_lookup_string(pCfg, INFLUXUSER_KEY, &influxUser)) {
-        influxUser = NULL;
-    }
-    fprintf(stderr, "CONFIG: influxUser=%s\n", (influxUser == NULL ? "<null>" : influxUser));
-    if (! config_lookup_string(pCfg, INFLUXPASS_KEY, &influxPass)) {
-        influxPass = NULL;
-    }
-    fprintf(stderr, "CONFIG: influxPass=%s\n", (influxPass == NULL ? "<null>" : influxPass));
-    if (! config_lookup_string(pCfg, LOCATION_KEY, &location)) {
-        location = DEFAULT_LOCATION;
-    }
-    fprintf(stderr, "CONFIG: location=%s\n", location);
-    if (! config_lookup_string(pCfg, INFLUXTAG_KEY, &influxTag)) {
-        gethostname(hostname, HOSTNAMESIZE);
-        influxTag = hostname;
-    }
-    fprintf(stderr, "CONFIG: influxTag=%s\n", influxTag);
-    influxBuffers[PERIOD_20MS] = (tInfluxBuffer*) malloc(sizeof(tInfluxBuffer));
-    influxClearBuffer(influxBuffers[PERIOD_20MS], true);
-    influxBuffers[PERIOD_1S] = (tInfluxBuffer*) malloc(sizeof(tInfluxBuffer));
-    influxClearBuffer(influxBuffers[PERIOD_1S], true);
-}
-
-
-
-static void influxSendRequest(tInfluxBuffer *influxBuffer) {
-    led(E_RED, false);
-    led(E_BLUE, true);
-    CURL *curl = curl_easy_init();
-    if(curl) {
-        curl_easy_setopt(curl, CURLOPT_URL, influxUrl);
-        if (influxUser && influxPass) {
-            curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_DIGEST);
-            curl_easy_setopt(curl, CURLOPT_USERNAME, influxUser);
-            curl_easy_setopt(curl, CURLOPT_PASSWORD, influxPass);
-        }
-        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, influxBuffer->buffer);
-        CURLcode res = curl_easy_perform(curl);
-        if(res != CURLE_OK) {
-            logmsg(LOG_ERR, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
-            led(E_RED, true);
-        }
-        curl_easy_cleanup(curl);
-    }
-    led(E_BLUE, false);
-}
-
-void influxAddFrequency(uint32_t period, double fRaw, double fSmoothed, double gradient, 
-                        int valid) {
-    static uint8_t divider = 0;
-    static uint32_t summedUpTime = 0;
-    char tmpBuf[256];
-    struct timespec t;
-
-    clock_gettime(CLOCK_REALTIME, &t);
-    uint64_t tt = (((uint64_t)t.tv_sec) * 1000) + (((uint64_t)t.tv_nsec) / 1000000);
-    int c = sprintf(tmpBuf, "mainsfrequency,host=%s,valid=%d,location=%s "
-                            "period=%u,freq=%f,freqSmoothed=%f,gradient=%f,freqRaw=%f "
-                            "%llu\n",
-                            influxTag, valid, location, 
-                            period, fSmoothed, fSmoothed, gradient, fRaw, 
-                            tt);
-
-    if ((influxBuffers[PERIOD_20MS]->nextEntry + c + 10) > (influxBuffers[PERIOD_20MS]->buffer + BUFSIZE)) {
-        influxSendRequest(influxBuffers[PERIOD_20MS]);
-        influxBuffers[PERIOD_20MS]->totalEntries += influxBuffers[PERIOD_20MS]->entries;
-        logmsg(LOG_INFO, "%u 20ms-entries sent to database, in total %u, invalid: %u\n", 
-            influxBuffers[PERIOD_20MS]->entries, influxBuffers[PERIOD_20MS]->totalEntries, skipped);
-        influxClearBuffer(influxBuffers[PERIOD_20MS], false);
-    }
-
-    memcpy(influxBuffers[PERIOD_20MS]->nextEntry, tmpBuf, c);
-    influxBuffers[PERIOD_20MS]->nextEntry += c;
-    influxBuffers[PERIOD_20MS]->entries += 1;
-
-    summedUpTime += period;
-    divider += 1;
-
-    if (divider == ONE_SECOND_DIVIDER) {
-        double freq1S = ((double)ONE_SECOND_DIVIDER) / (((double)summedUpTime) / 1000000.0); 
-        logmsg(LOG_DEBUG, "%llu: %u %f\n", tt, summedUpTime, freq1S);
-
-        int c = sprintf(tmpBuf, "mainsfrequency1S,host=%s,location=%s "
-                                "freq=%f "
-                                "%llu\n",
-                                influxTag, location, 
-                                freq1S, 
-                                tt);
-
-        //if ((influxBuffers[PERIOD_1S]->nextEntry + c + 10) > (influxBuffers[PERIOD_1S]->buffer + BUFSIZE)) {
-        if (influxBuffers[PERIOD_1S]->entries == 30) {
-            influxSendRequest(influxBuffers[PERIOD_1S]);
-            influxBuffers[PERIOD_1S]->totalEntries += influxBuffers[PERIOD_1S]->entries;
-            logmsg(LOG_INFO, "%u 1s-entries sent to database, in total %u\n", 
-                influxBuffers[PERIOD_1S]->entries, influxBuffers[PERIOD_1S]->totalEntries);
-            influxClearBuffer(influxBuffers[PERIOD_1S], false);
-        }
-
-        memcpy(influxBuffers[PERIOD_1S]->nextEntry, tmpBuf, c);
-        influxBuffers[PERIOD_1S]->nextEntry += c;
-        influxBuffers[PERIOD_1S]->entries += 1;
-
-        divider = 0;
-        summedUpTime = 0.0;
-    }
-}
-
-

src/influx.h

@@ -1,9 +0,0 @@
-#ifndef _INFLUX_H_
-#define _INFLUX_H_
-
-#include <libconfig.h>
-
-void influxAddFrequency(uint32_t period, double fRaw, double fSmoothed, double gradient, int valid);
-void influxInit(config_t *pCfg);
-
-#endif // _INFLUX_H_

src/led.c

@@ -1,32 +1,46 @@
 #include <stdbool.h>
 #include <wiringPi.h>
+#include <libconfig.h>
+#include <stdbool.h>
+#include <strings.h>
 
 #include "led.h"
+#include "logging.h"
 
 
+const char LED_KEY[] = "led";
+const char DEFAULT_LED[] = "off";
+const char *ledsActiveStr;
+bool ledsActive;
 
 const int GREEN_OUT = 20;
 const int RED_OUT = 21;
 const int BLUE_OUT = 26;
 
-void ledInit() {
+void ledInit(config_t *pCfg) {
-    pinMode(GREEN_OUT, OUTPUT);
+  if (! config_lookup_string(pCfg, LED_KEY, &ledsActiveStr)) {
-    digitalWrite(GREEN_OUT, 0);
+    ledsActiveStr = DEFAULT_LED;
+  }
+  ledsActive = (0 == strcasecmp(ledsActiveStr, "on")) || (0 == strcasecmp(ledsActiveStr, "true"));
+  logmsg(LOG_INFO, "CONFIG: ledsActive=%d, ledsActiveStr=%s\n", ledsActive, ledsActiveStr);
 
-    pinMode(RED_OUT, OUTPUT);
+  pinMode(GREEN_OUT, OUTPUT);
-    digitalWrite(RED_OUT, 0);
+  digitalWrite(GREEN_OUT, 0);
 
-    pinMode(BLUE_OUT, OUTPUT);
+  pinMode(RED_OUT, OUTPUT);
-    digitalWrite(BLUE_OUT, 0);
+  digitalWrite(RED_OUT, 0);
+
+  pinMode(BLUE_OUT, OUTPUT);
+  digitalWrite(BLUE_OUT, 0);
 }
 
 
 void led (tColor color, bool state) {
-    if (color == E_RED) {
+  if (color == E_RED) {
-        digitalWrite(RED_OUT, state ? 1 : 0);
+    digitalWrite(RED_OUT, state ? 1 : 0);
-    } else if (color == E_BLUE) {
+  } else if (color == E_BLUE && ledsActive) {
-        digitalWrite(BLUE_OUT, state ? 1 : 0);
+    digitalWrite(BLUE_OUT, state ? 1 : 0);
-    } else if (color == E_GREEN) {
+  } else if (color == E_GREEN && ledsActive) {
-        digitalWrite(GREEN_OUT, state ? 1 : 0);
+    digitalWrite(GREEN_OUT, state ? 1 : 0);
-    }
+  }
 }

src/led.h

@@ -2,10 +2,11 @@
 #define _LED_H_
 
 #include <stdbool.h>
+#include <libconfig.h>
 
 typedef enum { E_RED, E_BLUE, E_GREEN } tColor;
 
-void ledInit();
+void ledInit(config_t *pCfg);
 void led(tColor color, bool state);
 
 #endif // _LED_H_

src/sha256.c

@@ -0,0 +1,158 @@
+/*********************************************************************
+* Filename:   sha256.c
+* Author:     Brad Conte (brad AT bradconte.com)
+* Copyright:
+* Disclaimer: This code is presented "as is" without any guarantees.
+* Details:    Implementation of the SHA-256 hashing algorithm.
+              SHA-256 is one of the three algorithms in the SHA2
+              specification. The others, SHA-384 and SHA-512, are not
+              offered in this implementation.
+              Algorithm specification can be found here:
+               * http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf
+              This implementation uses little endian byte order.
+*********************************************************************/
+
+/*************************** HEADER FILES ***************************/
+#include <stdlib.h>
+#include <memory.h>
+#include "sha256.h"
+
+/****************************** MACROS ******************************/
+#define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b))))
+#define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b))))
+
+#define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z)))
+#define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+#define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22))
+#define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25))
+#define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3))
+#define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10))
+
+/**************************** VARIABLES *****************************/
+static const WORD k[64] = {
+	0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
+	0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
+	0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
+	0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
+	0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
+	0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
+	0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
+	0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
+};
+
+/*********************** FUNCTION DEFINITIONS ***********************/
+void sha256_transform(SHA256_CTX *ctx, const BYTE data[])
+{
+	WORD a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];
+
+	for (i = 0, j = 0; i < 16; ++i, j += 4)
+		m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]);
+	for ( ; i < 64; ++i)
+		m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16];
+
+	a = ctx->state[0];
+	b = ctx->state[1];
+	c = ctx->state[2];
+	d = ctx->state[3];
+	e = ctx->state[4];
+	f = ctx->state[5];
+	g = ctx->state[6];
+	h = ctx->state[7];
+
+	for (i = 0; i < 64; ++i) {
+		t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i];
+		t2 = EP0(a) + MAJ(a,b,c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + t1;
+		d = c;
+		c = b;
+		b = a;
+		a = t1 + t2;
+	}
+
+	ctx->state[0] += a;
+	ctx->state[1] += b;
+	ctx->state[2] += c;
+	ctx->state[3] += d;
+	ctx->state[4] += e;
+	ctx->state[5] += f;
+	ctx->state[6] += g;
+	ctx->state[7] += h;
+}
+
+void sha256_init(SHA256_CTX *ctx)
+{
+	ctx->datalen = 0;
+	ctx->bitlen = 0;
+	ctx->state[0] = 0x6a09e667;
+	ctx->state[1] = 0xbb67ae85;
+	ctx->state[2] = 0x3c6ef372;
+	ctx->state[3] = 0xa54ff53a;
+	ctx->state[4] = 0x510e527f;
+	ctx->state[5] = 0x9b05688c;
+	ctx->state[6] = 0x1f83d9ab;
+	ctx->state[7] = 0x5be0cd19;
+}
+
+void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len)
+{
+	WORD i;
+
+	for (i = 0; i < len; ++i) {
+		ctx->data[ctx->datalen] = data[i];
+		ctx->datalen++;
+		if (ctx->datalen == 64) {
+			sha256_transform(ctx, ctx->data);
+			ctx->bitlen += 512;
+			ctx->datalen = 0;
+		}
+	}
+}
+
+void sha256_final(SHA256_CTX *ctx, BYTE hash[])
+{
+	WORD i;
+
+	i = ctx->datalen;
+
+	// Pad whatever data is left in the buffer.
+	if (ctx->datalen < 56) {
+		ctx->data[i++] = 0x80;
+		while (i < 56)
+			ctx->data[i++] = 0x00;
+	}
+	else {
+		ctx->data[i++] = 0x80;
+		while (i < 64)
+			ctx->data[i++] = 0x00;
+		sha256_transform(ctx, ctx->data);
+		memset(ctx->data, 0, 56);
+	}
+
+	// Append to the padding the total message's length in bits and transform.
+	ctx->bitlen += ctx->datalen * 8;
+	ctx->data[63] = ctx->bitlen;
+	ctx->data[62] = ctx->bitlen >> 8;
+	ctx->data[61] = ctx->bitlen >> 16;
+	ctx->data[60] = ctx->bitlen >> 24;
+	ctx->data[59] = ctx->bitlen >> 32;
+	ctx->data[58] = ctx->bitlen >> 40;
+	ctx->data[57] = ctx->bitlen >> 48;
+	ctx->data[56] = ctx->bitlen >> 56;
+	sha256_transform(ctx, ctx->data);
+
+	// Since this implementation uses little endian byte ordering and SHA uses big endian,
+	// reverse all the bytes when copying the final state to the output hash.
+	for (i = 0; i < 4; ++i) {
+		hash[i]      = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 4]  = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 8]  = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff;
+		hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff;
+	}
+}

src/sha256.h

@@ -0,0 +1,35 @@
+/*********************************************************************
+* Filename:   sha256.h
+* Author:     Brad Conte (brad AT bradconte.com)
+* Copyright:
+* Disclaimer: This code is presented "as is" without any guarantees.
+* Details:    Defines the API for the corresponding SHA1 implementation.
+*********************************************************************/
+
+#ifndef SHA256_H
+#define SHA256_H
+
+/*************************** HEADER FILES ***************************/
+#include <stddef.h>
+#include <stdint.h>
+
+/****************************** MACROS ******************************/
+#define SHA256_BLOCK_SIZE 32            // SHA256 outputs a 32 byte digest
+
+/**************************** DATA TYPES ****************************/
+typedef uint8_t BYTE;             // 8-bit byte
+typedef uint32_t  WORD;             // 32-bit word, change to "long" for 16-bit machines
+
+typedef struct {
+	BYTE data[64];
+	WORD datalen;
+	unsigned long long bitlen;
+	WORD state[8];
+} SHA256_CTX;
+
+/*********************** FUNCTION DECLARATIONS **********************/
+void sha256_init(SHA256_CTX *ctx);
+void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len);
+void sha256_final(SHA256_CTX *ctx, BYTE hash[]);
+
+#endif   // SHA256_H

src/sinkSender.c

@@ -0,0 +1,148 @@
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <libconfig.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <sys/sysinfo.h>
+#include <unistd.h>
+#include <stdbool.h>
+
+#include "sinkSender.h"
+#include "logging.h"
+#include "led.h"
+#include "sinkStruct.h"
+#include "sha256.h"
+
+
+const char SINKSERVER_KEY[] = "sinkServer";
+const char DEFAULT_SINKSERVER[] = "sink.hottis.de";
+const char *sinkServer;
+const char SINKPORT_KEY[] = "sinkPort";
+const int DEFAULT_SINKPORT = 20169;
+int sinkPort;
+const char DEVICE_ID_KEY[] = "deviceId";
+const char DEFAULT_DEVICE_ID[] = "mainscnt00";
+const char *deviceId;
+const char SHARED_SECRET_KEY[] = "sharedSecret";
+const char DEFAULT_SHARED_SECRET[] = "1234567890123456789012345678901";
+const char *sharedSecret;
+
+static t_minuteBuffer minuteBuffer;
+static uint32_t secondOfMinute;
+
+extern char VERSION[];
+
+
+void sinkSenderInit(config_t *pCfg) {
+  if (! config_lookup_string(pCfg, SINKSERVER_KEY, &sinkServer)) {
+    sinkServer = DEFAULT_SINKSERVER;
+  }
+  logmsg(LOG_INFO, "CONFIG: sinkServer=%s\n", sinkServer);
+  if (! config_lookup_int(pCfg, SINKPORT_KEY, &sinkPort)) {
+    sinkPort = DEFAULT_SINKPORT;
+  }
+  logmsg(LOG_INFO, "CONFIG: sinkPort=%u\n", sinkPort);
+  if (! config_lookup_string(pCfg, DEVICE_ID_KEY, &deviceId)) {
+    deviceId = DEFAULT_DEVICE_ID;
+  }
+  logmsg(LOG_INFO, "CONFIG: deviceId=%s\n", deviceId);
+  if (! config_lookup_string(pCfg, SHARED_SECRET_KEY, &sharedSecret)) {
+    sharedSecret = DEFAULT_SHARED_SECRET;
+  }
+
+
+  secondOfMinute = 0;
+}
+
+
+static void sinkSenderSendMinute() {
+  led(E_BLUE, true);
+  led(E_RED, false);
+
+  struct sysinfo info;
+  sysinfo(&info);
+
+  minuteBuffer.s.totalRunningHours = info.uptime / 3600;
+  minuteBuffer.s.totalPowercycles = 0;
+  minuteBuffer.s.totalWatchdogResets = 0;
+  minuteBuffer.s.version = strtoll(VERSION, NULL, 16);
+
+  memset(minuteBuffer.s.deviceId, 0, sizeof(minuteBuffer.s.deviceId));
+  strcpy(minuteBuffer.s.deviceId, deviceId);
+
+  memcpy(minuteBuffer.s.hash, sharedSecret, SHA256_BLOCK_SIZE);
+  SHA256_CTX ctx;
+  sha256_init(&ctx);
+  sha256_update(&ctx, minuteBuffer.b, sizeof(minuteBuffer.b));
+  sha256_final(&ctx, minuteBuffer.s.hash);
+
+  struct hostent *hptr = gethostbyname(sinkServer);
+  if (hptr) {
+    if (hptr->h_addrtype == AF_INET) {
+      char *sinkAddr = hptr->h_addr_list[0];
+      logmsg(LOG_DEBUG, "sink addr: %d.%d.%d.%d", 
+              sinkAddr[0], sinkAddr[1], sinkAddr[2], sinkAddr[3]);
+
+      int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+      if (sockfd != -1) {
+        struct sockaddr_in servaddr;
+        memset(&servaddr, 0, sizeof(servaddr));
+        servaddr.sin_family = AF_INET;
+        servaddr.sin_port = htons(sinkPort);
+        memcpy(&servaddr.sin_addr.s_addr, sinkAddr, 4);
+
+        ssize_t res = sendto(sockfd, minuteBuffer.b, sizeof(minuteBuffer.b), 
+                              0, (struct sockaddr*)&servaddr, 
+                              sizeof(servaddr));
+        logmsg(LOG_DEBUG, "%d octets sent", res);
+
+        int rc = close(sockfd);
+        if (rc == -1) {
+          logmsg(LOG_ERR, "close on socket returns %s", strerror(errno));
+        }
+      } else {
+        led(E_RED, true);
+        logmsg(LOG_ERR, "unable to get socket: %s", strerror(errno));
+      }
+    } else {
+      led(E_RED, true);
+      logmsg(LOG_ERR, "unknown address type: %d", hptr->h_addrtype);
+    }
+  } else {
+    led(E_RED, true);
+    logmsg(LOG_ERR, "sinkserver %s couldn't be resolved: %s", sinkServer, hstrerror(h_errno));
+  }
+
+  led(E_BLUE, false);
+}
+
+
+void sinkSenderPut(uint32_t seconds, uint32_t frequency) {
+  static bool settled = false;
+
+  led(E_GREEN, false);
+  logmsg(LOG_DEBUG, "s: %lu, f: %lu", seconds, frequency);
+
+  if (secondOfMinute == 0) {
+    minuteBuffer.s.timestamp = seconds;
+  }
+  minuteBuffer.s.frequency[secondOfMinute] = frequency;
+  secondOfMinute += 1;
+
+  if (secondOfMinute == SECONDS_PER_MINUTE) {
+    logmsg(LOG_DEBUG, "minute is full");
+    secondOfMinute = 0;
+    
+    if (settled) {
+      sinkSenderSendMinute();
+    } else {
+      logmsg(LOG_INFO, "now it is settled");
+      settled = true;
+    }
+  }
+
+  led(E_GREEN, true);
+}

src/sinkSender.h

@@ -0,0 +1,10 @@
+#ifndef _SINKSENDER_H_
+#define _SINKSENDER_H_
+
+#include <libconfig.h>
+
+
+void sinkSenderInit(config_t *pCfg);
+void sinkSenderPut(uint32_t seconds, uint32_t frequency);
+
+#endif // _SINKSENDER_H_

src/sinkStruct.h

@@ -0,0 +1,26 @@
+#ifndef _SINKSTRUCT_H_
+#define _SINKSTRUCT_H_
+
+#include <stdint.h>
+#include "sha256.h"
+
+#define DEVICE_ID_SIZE 16
+#define SECONDS_PER_MINUTE 60
+
+typedef struct __attribute__((__packed__)) {
+    char deviceId[DEVICE_ID_SIZE];
+    uint8_t hash[SHA256_BLOCK_SIZE];
+    uint32_t totalRunningHours;
+    uint32_t totalPowercycles;
+    uint32_t totalWatchdogResets;
+    uint32_t version;
+    uint64_t timestamp;
+    uint32_t frequency[SECONDS_PER_MINUTE];
+} t_minuteStruct;
+
+typedef union {
+    t_minuteStruct s;
+    uint8_t b[sizeof(t_minuteStruct)];
+} t_minuteBuffer;
+
+#endif // _SINKSTRUCT_H_