Reap old subproxies when they're no longer in use

src/generator.c

@@ -1314,6 +1314,30 @@ static proxy_instance_t *subproxy_by_id(proxy_instance_t *proxy, const int subid
 	return subproxy;
 }
 
+static void drop_proxy(gdata_t *gdata, const char *buf)
+{
+	proxy_instance_t *proxy, *subproxy;
+	int id  = 0, subid = 0;
+
+	sscanf(buf, "dropproxy=%d:%d", &id, &subid);
+	if (unlikely(!subid)) {
+		LOGWARNING("Generator asked to drop parent proxy %d", id);
+		return;
+	}
+	proxy = proxy_by_id(gdata, id);
+	if (unlikely(!proxy)) {
+		LOGINFO("Generator asked to drop subproxy from non-existent parent %d", id);
+		return;
+	}
+	subproxy = subproxy_by_id(proxy, subid);
+	if (!subproxy) {
+		LOGINFO("Generator asked to drop non-existent subproxy %d:%d", id, subid);
+		return;
+	}
+	LOGNOTICE("Generator asked to drop proxy %d:%d", id, subid);
+	disable_subproxy(gdata, proxy, subproxy);
+}
+
 static void stratifier_reconnect_client(ckpool_t *ckp, int64_t id)
 {
 	char buf[256];
@@ -1984,6 +2008,8 @@ retry:
 		send_unix_msg(sockd, "pong");
 	} else if (cmdmatch(buf, "recruit")) {
 		recruit_subproxy(proxi);
+	} else if (cmdmatch(buf, "dropproxy")) {
+		drop_proxy(gdata, buf);
 	} else if (ckp->passthrough) {
 		/* Anything remaining should be stratum messages */
 		passthrough_add_send(proxi, buf);

src/stratifier.c

@@ -1472,6 +1472,48 @@ static void update_diff(ckpool_t *ckp, const char *cmd)
 	ck_runlock(&sdata->instance_lock);
 }
 
+static void generator_drop_proxy(ckpool_t *ckp, const int id, const int subid)
+{
+	char msg[256];
+
+	sprintf(msg, "dropproxy=%d:%d", id, subid);
+	send_generator(ckp, msg, GEN_LAX);
+}
+
+/* Remove subproxies that are flagged dead or have used up their quota of
+ * clients and inform the generator if it is still alive */
+static void reap_proxies(ckpool_t *ckp, sdata_t *sdata)
+{
+	proxy_t *proxy, *proxytmp, *subproxy, *subtmp;
+
+	if (!ckp->proxy)
+		return;
+
+	mutex_lock(&sdata->proxy_lock);
+	HASH_ITER(hh, sdata->proxies, proxy, proxytmp) {
+		HASH_ITER(sh, proxy->subproxies, subproxy, subtmp) {
+			if (proxy == subproxy)
+				continue;
+			if (subproxy->bound_clients)
+				continue;
+			if (!subproxy->dead) {
+				if (subproxy->clients < subproxy->max_clients)
+					continue;
+				generator_drop_proxy(ckp, subproxy->id, subproxy->subid);
+				LOGNOTICE("Stratifier discarding used proxy %d:%d",
+					  subproxy->id, subproxy->subid);
+			} else {
+				LOGNOTICE("Stratifier discarding dead proxy %d:%d",
+					  subproxy->id, subproxy->subid);
+			}
+			HASH_DELETE(sh, proxy->subproxies, subproxy);
+			free(subproxy->sdata);
+			free(subproxy);
+		}
+	}
+	mutex_unlock(&sdata->proxy_lock);
+}
+
 /* Enter with instance_lock held */
 static stratum_instance_t *__instance_by_id(sdata_t *sdata, const int64_t id)
 {
@@ -1589,6 +1631,9 @@ static void _dec_instance_ref(sdata_t *sdata, stratum_instance_t *client, const
 	/* This should never happen */
 	if (unlikely(ref < 0))
 		LOGERR("Instance ref count dropped below zero from %s %s:%d", file, func, line);
+
+	if (dropped)
+		reap_proxies(sdata->ckp, sdata);
 }
 
 #define dec_instance_ref(sdata, instance) _dec_instance_ref(sdata, instance, __FILE__, __func__, __LINE__)
@@ -1786,11 +1831,13 @@ static void drop_client(ckpool_t *ckp, sdata_t *sdata, const int64_t id)
 	client_drop_message(id, dropped, false);
 	if (aged)
 		LOGINFO("Aged %d disconnected instances to dead", aged);
-
 	/* Decrease worker count outside of instance_lock to avoid recursive
 	 * locking */
 	if (user)
 		dec_worker(ckp, user);
+
+	if (aged || dropped)
+		reap_proxies(ckp, sdata);
 }
 
 static void stratum_broadcast_message(sdata_t *sdata, const char *msg)