1 files changed, 140 insertions, 0 deletions
diff --git a/include/internal/quic_cfq.h b/include/internal/quic_cfq.h
new file mode 100644
index 0000000000..d5ac37ae43
--- /dev/null
+++ b/include/internal/quic_cfq.h
@@ -0,0 +1,140 @@
+/*
+ * Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef OSSL_QUIC_CFQ_H
+# define OSSL_QUIC_CFQ_H
+
+# include <openssl/ssl.h>
+# include "internal/quic_types.h"
+
+/*
+ * QUIC Control Frame Queue Item
+ * =============================
+ *
+ * The CFQ item structure has a public and a private part. This structure
+ * documents the public part.
+ */
+typedef struct quic_cfq_item_st QUIC_CFQ_ITEM;
+
+struct quic_cfq_item_st {
+    /*
+     * These fields are not used by the CFQ, but are a convenience to assist the
+     * TXPIM in keeping a list of GCR control frames which were sent in a
+     * packet. They may be used for any purpose.
+     */
+    QUIC_CFQ_ITEM  *pkt_prev, *pkt_next;
+
+    /* All other fields are private; use ossl_quic_cfq_item_* accessors. */
+};
+
+#define QUIC_CFQ_STATE_NEW      0
+#define QUIC_CFQ_STATE_TX       1
+
+/* Returns the frame type of a CFQ item. */
+uint64_t ossl_quic_cfq_item_get_frame_type(QUIC_CFQ_ITEM *item);
+
+/* Returns a pointer to the encoded buffer of a CFQ item. */
+const unsigned char *ossl_quic_cfq_item_get_encoded(QUIC_CFQ_ITEM *item);
+
+/* Returns the length of the encoded buffer in bytes. */
+size_t ossl_quic_cfq_item_get_encoded_len(QUIC_CFQ_ITEM *item);
+
+/* Returns the CFQ item state, a QUIC_CFQ_STATE_* value. */
+int ossl_quic_cfq_item_get_state(QUIC_CFQ_ITEM *item);
+
+/* Returns the PN space for the CFQ item. */
+uint32_t ossl_quic_cfq_item_get_pn_space(QUIC_CFQ_ITEM *item);
+
+/*
+ * QUIC Control Frame Queue
+ * ========================
+ */
+typedef struct quic_cfq_st QUIC_CFQ;
+
+QUIC_CFQ *ossl_quic_cfq_new(void);
+void ossl_quic_cfq_free(QUIC_CFQ *cfq);
+
+/*
+ * Input Side
+ * ----------
+ */
+
+/*
+ * Enqueue a frame to the CFQ.
+ *
+ * encoded points to the opaque encoded frame.
+ *
+ * free_cb is called by the CFQ when the buffer is no longer needed;
+ * free_cb_arg is an opaque value passed to free_cb.
+ *
+ * priority determines the relative ordering of control frames in a packet.
+ * Lower numerical values for priority mean that a frame should come earlier in
+ * a packet. pn_space is a QUIC_PN_SPACE_* value.
+ *
+ * On success, returns a QUIC_CFQ_ITEM pointer which acts as a handle to
+ * the queued frame. On failure, returns NULL.
+ *
+ * The frame is initially in the TX state, so there is no need to call
+ * ossl_quic_cfq_mark_tx() immediately after calling this function.
+ *
+ * The frame type is duplicated as the frame_type argument here, even though it
+ * is also encoded into the buffer. This allows the caller to determine the
+ * frame type if desired without having to decode the frame.
+ */
+typedef void (cfq_free_cb)(unsigned char *buf, size_t buf_len, void *arg);
+
+QUIC_CFQ_ITEM *ossl_quic_cfq_add_frame(QUIC_CFQ            *cfq,
+                                       uint32_t             priority,
+                                       uint32_t             pn_space,
+                                       uint64_t             frame_type,
+                                       const unsigned char *encoded,
+                                       size_t               encoded_len,
+                                       cfq_free_cb         *free_cb,
+                                       void                *free_cb_arg);
+
+/*
+ * Effects an immediate transition of the given CFQ item to the TX state.
+ */
+void ossl_quic_cfq_mark_tx(QUIC_CFQ *cfq, QUIC_CFQ_ITEM *item);
+
+/*
+ * Effects an immediate transition of the given CFQ item to the NEW state,
+ * allowing the frame to be retransmitted. If priority is not UINT32_MAX,
+ * the priority is changed to the given value.
+ */
+void ossl_quic_cfq_mark_lost(QUIC_CFQ *cfq, QUIC_CFQ_ITEM *item,
+                             uint32_t priority);
+
+/*
+ * Releases a CFQ item. The item may be in either state (NEW or TX) prior to the
+ * call. The QUIC_CFQ_ITEM pointer must not be used following this call.
+ */
+void ossl_quic_cfq_release(QUIC_CFQ *cfq, QUIC_CFQ_ITEM *item);
+
+/*
+ * Output Side
+ * -----------
+ */
+
+/*
+ * Gets the highest priority CFQ item in the given PN space awaiting
+ * transmission. If there are none, returns NULL.
+ */
+QUIC_CFQ_ITEM *ossl_quic_cfq_get_priority_head(QUIC_CFQ *cfq, uint32_t pn_space);
+
+/*
+ * Given a CFQ item, gets the next CFQ item awaiting transmission in priority
+ * order in the given PN space. In other words, given the return value of
+ * ossl_quic_cfq_get_priority_head(), returns the next-lower priority item.
+ * Returns NULL if the given item is the last item in priority order.
+ */
+QUIC_CFQ_ITEM *ossl_quic_cfq_item_get_priority_next(QUIC_CFQ_ITEM *item,
+                                                    uint32_t pn_space);
+
+#endif