Use ping/pongs to determine if upstream pool is still alive

src/ckpool.h

@@ -277,6 +277,7 @@ enum stratum_msgtype {
 	SM_WORKINFO,
 	SM_SUGGESTDIFF,
 	SM_BLOCK,
+	SM_PONG,
 	SM_NONE
 };
 
@@ -298,6 +299,7 @@ static const char __maybe_unused *stratum_msgs[] = {
 	"workinfo",
 	"suggestdiff",
 	"block",
+	"pong",
 	""
 };
 

src/connector.c

@@ -1094,11 +1094,21 @@ static void parse_remote_submitblock(ckpool_t *ckp, const json_t *val, const cha
 	send_proc(ckp->generator, gbt_block);
 }
 
+static void ping_upstream(cdata_t *cdata)
+{
+	char *buf;
+
+	ASPRINTF(&buf, "{\"method\":\"ping\"}\n");
+	ckmsgq_add(cdata->upstream_sends, buf);
+}
+
 static void *urecv_process(void *arg)
 {
 	ckpool_t *ckp = (ckpool_t *)arg;
 	cdata_t *cdata = ckp->data;
 	connsock_t *cs = &cdata->upstream_cs;
+	bool alive = true;
+
 	ckp->proxy = true;
 
 	rename_proc("ureceiver");
@@ -1114,12 +1124,16 @@ static void *urecv_process(void *arg)
 		cksem_wait(&cs->sem);
 		ret = read_socket_line(cs, &timeout);
 		if (ret < 1) {
-			if (likely(!ret))
+			ping_upstream(cdata);
+			if (likely(!ret)) {
 				LOGDEBUG("No message from upstream pool");
-			else
+			} else {
 				LOGNOTICE("Failed to read from upstream pool");
+				alive = false;
+			}
 			goto nomsg;
 		}
+		alive = true;
 		val = json_loads(cs->buf, 0, NULL);
 		if (unlikely(!val)) {
 			LOGWARNING("Received non-json msg from upstream pool %s",
@@ -1135,10 +1149,15 @@ static void *urecv_process(void *arg)
 		}
 		if (!safecmp(method, "submitblock"))
 			parse_remote_submitblock(ckp, val, cs->buf);
+		else if (!safecmp(method, "pong"))
+			LOGDEBUG("Received upstream pong");
 		else
 			LOGWARNING("Unrecognised upstream method %s", method);
 nomsg:
 		cksem_post(&cs->sem);
+
+		if (!alive)
+			sleep(5);
 	}
 	return NULL;
 }

src/stratifier.c

@@ -5999,6 +5999,14 @@ static void parse_remote_block(sdata_t *sdata, json_t *val, const char *buf)
 	reset_bestshares(sdata);
 }
 
+static void send_remote_pong(sdata_t *sdata, stratum_instance_t *client)
+{
+	json_t *json_msg;
+
+	JSON_CPACK(json_msg, "{ss}", "method", "pong");
+	stratum_add_send(sdata, json_msg, client->id, SM_PONG);
+}
+
 static void parse_trusted_msg(ckpool_t *ckp, sdata_t *sdata, json_t *val, const char *buf,
 			      stratum_instance_t *client)
 {
@@ -6019,6 +6027,8 @@ static void parse_trusted_msg(ckpool_t *ckp, sdata_t *sdata, json_t *val, const
 		parse_remote_blocksubmit(ckp, val, buf, client);
 	else if (!safecmp(method, "block"))
 		parse_remote_block(sdata, val, buf);
+	else if (!safecmp(method, "ping"))
+		send_remote_pong(sdata, client);
 	else
 		LOGWARNING("unrecognised trusted message %s", buf);
 }