Get the network difficulty from the block header and use that to determine possible block solves in proxy mode

src/libckpool.c

@@ -1565,16 +1565,16 @@ double diff_from_target(uchar *target)
 
 /* Return the network difficulty from the block header which is in packed form,
  * as a double. */
-double diff_from_header(uchar *header)
+double diff_from_nbits(char *nbits)
 {
 	double numerator;
 	uint32_t diff32;
 	uint8_t pow;
 	int powdiff;
 
-	pow = header[72];
+	pow = nbits[0];
 	powdiff = (8 * (0x1d - 3)) - (8 * (pow - 3));
-	diff32 = be32toh(*((uint32_t *)(header + 72))) & 0x00FFFFFF;
+	diff32 = be32toh(*((uint32_t *)nbits)) & 0x00FFFFFF;
 	numerator = 0xFFFFULL << powdiff;
 	return numerator / (double)diff32;
 }

src/libckpool.h

@@ -380,7 +380,7 @@ void suffix_string(double val, char *buf, size_t bufsiz, int sigdigits);
 
 double le256todouble(const uchar *target);
 double diff_from_target(uchar *target);
-double diff_from_header(uchar *header);
+double diff_from_nbits(char *nbits);
 void target_from_diff(uchar *target, double diff);
 
 void gen_hash(uchar *data, uchar *hash, int len);

src/stratifier.c

@@ -88,6 +88,7 @@ struct workbase {
 	/* GBT/shared variables */
 	char target[68];
 	double diff;
+	double network_diff;
 	uint32_t version;
 	uint32_t curtime;
 	char prevhash[68];
@@ -367,6 +368,7 @@ static void add_base(ckpool_t *ckp, workbase_t *wb, bool *new_block)
 	int len, ret;
 
 	wb->gentime = time(NULL);
+	wb->network_diff = diff_from_nbits(wb->headerbin + 72);
 
 	len = strlen(ckp->logdir) + 8 + 1 + 16;
 	wb->logdir = ckalloc(len);
@@ -1184,7 +1186,11 @@ static void test_blocksolve(workbase_t *wb, const uchar *data, double diff, cons
 	char hexcoinbase[512];
 
 	/* Submit anything over 95% of the diff in case of rounding errors */
-	if (diff < current_workbase->diff * 0.95)
+	if (diff < current_workbase->network_diff * 0.95)
+		return;
+
+	LOGWARNING("Possible block solve diff %f !", diff);
+	if (wb->proxy)
 		return;
 
 	gbt_block = ckalloc(512);
@@ -1268,7 +1274,6 @@ static double submission_diff(stratum_instance_t *client, workbase_t *wb, const
 	ret = diff_from_target(hash);
 
 	/* Test we haven't solved a block regardless of share status */
-	if (!wb->proxy)
 	test_blocksolve(wb, swap, ret, coinbase, cblen);
 
 	return ret;