1 files changed, 134 insertions, 0 deletions
diff --git a/include/haproxy/queue.h b/include/haproxy/queue.h
new file mode 100644
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--- /dev/null
+++ b/include/haproxy/queue.h
@@ -0,0 +1,134 @@
+/*
+ * include/haproxy/queue.h
+ * This file defines everything related to queues.
+ *
+ * Copyright (C) 2000-2020 Willy Tarreau - w@1wt.eu
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _HAPROXY_QUEUE_H
+#define _HAPROXY_QUEUE_H
+
+#include <haproxy/api.h>
+#include <haproxy/backend.h>
+#include <haproxy/pool.h>
+#include <haproxy/proxy-t.h>
+#include <haproxy/queue-t.h>
+#include <haproxy/server-t.h>
+#include <haproxy/stream-t.h>
+
+extern struct pool_head *pool_head_pendconn;
+
+struct pendconn *pendconn_add(struct stream *strm);
+int pendconn_dequeue(struct stream *strm);
+void process_srv_queue(struct server *s);
+unsigned int srv_dynamic_maxconn(const struct server *s);
+int pendconn_redistribute(struct server *s);
+int pendconn_grab_from_px(struct server *s);
+void pendconn_unlink(struct pendconn *p);
+
+/* Removes the pendconn from the server/proxy queue. It supports being called
+ * with NULL for pendconn and with a pendconn not in the list. It is the
+ * function to be used by default when unsure. Do not call it with server
+ * or proxy locks held however. Warning: this is called from stream_free()
+ * which may run concurrently with pendconn_process_next_strm() which can be
+ * dequeuing the entry. The function must not return until the pendconn is
+ * guaranteed not to be known, which means that we must check its presence
+ * in the tree under the queue's lock so that penconn_process_next_strm()
+ * finishes before we return in case it would have grabbed this pendconn. See
+ * github bugs #880 and #908, and the commit log for this fix for more details.
+ */
+static inline void pendconn_cond_unlink(struct pendconn *p)
+{
+	if (p)
+		pendconn_unlink(p);
+}
+
+/* Releases the pendconn associated to stream <s> if it has any, and decreases
+ * the pending count if needed. The connection might have been queued to a
+ * specific server as well as to the proxy. The stream also gets marked
+ * unqueued.
+ *
+ * This function must be called by the stream itself, so in the context of
+ * process_stream, without any lock held among the pendconn, the server's queue
+ * nor the proxy's queue.
+ */
+static inline void pendconn_free(struct stream *s)
+{
+	struct pendconn *p = s->pend_pos;
+
+	if (p) {
+		pendconn_cond_unlink(p);
+		s->pend_pos = NULL;
+		pool_free(pool_head_pendconn, p);
+	}
+}
+
+/* Returns 0 if all slots are full on a server, or 1 if there are slots available. */
+static inline int server_has_room(const struct server *s) {
+	return !s->maxconn || s->cur_sess < srv_dynamic_maxconn(s);
+}
+
+/* returns 0 if nothing has to be done for server <s> regarding queued connections,
+ * and non-zero otherwise. If the server is down, we only check its own queue. Suited
+ * for and if/else usage.
+ */
+static inline int may_dequeue_tasks(const struct server *s, const struct proxy *p) {
+	return (s && (s->queue.length || (p->queue.length && srv_currently_usable(s))) &&
+		(!s->maxconn || s->cur_sess < srv_dynamic_maxconn(s)));
+}
+
+static inline int queue_limit_class(int class)
+{
+	if (class < -0x7ff)
+		return -0x7ff;
+	if (class > 0x7ff)
+		return 0x7ff;
+	return class;
+}
+
+static inline int queue_limit_offset(int offset)
+{
+	if (offset < -0x7ffff)
+		return -0x7ffff;
+	if (offset > 0x7ffff)
+		return 0x7ffff;
+	return offset;
+}
+
+/* initialize the queue <queue> for proxy <px> and server <sv>. A server's
+ * always has both a valid proxy and a valid server. A proxy's queue only
+ * has a valid proxy and NULL for the server queue. This is how they're
+ * distinguished during operations.
+ */
+static inline void queue_init(struct queue *queue, struct proxy *px, struct server *sv)
+{
+	queue->head = EB_ROOT;
+	queue->length = 0;
+	queue->idx = 0;
+	queue->px = px;
+	queue->sv = sv;
+	HA_SPIN_INIT(&queue->lock);
+}
+
+#endif /* _HAPROXY_QUEUE_H */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ */