1/* Copyright (c) 2017 - 2022 LiteSpeed Technologies Inc.  See LICENSE. */
2/*
3 * lsquic_hpi.h - HPI: (Extensible) HTTP Priority Iterator
4 *
5 * https://tools.ietf.org/html/draft-ietf-httpbis-priority-01
6 *
7 * Changing a stream's priority when the stream is in the iterator
8 * does not change the stream's position in the iterator.
9 */
10
11#ifndef LSQUIC_HPI
12#define LSQUIC_HPI 1
13
14#ifndef LSQUIC_TEST
15#define LSQUIC_TEST 0
16#endif
17
18struct lsquic_conn_public;
19
20/* We add 1 to the urgency when we place them on hpi_streams.  Critical
21 * streams get the highest-priority slot zero.
22 */
23#define N_HPI_PRIORITIES (2 + LSQUIC_MAX_HTTP_URGENCY)
24
25
26struct http_prio_iter
27{
28    const char                     *hpi_name;           /* Used for logging */
29    struct lsquic_conn_public      *hpi_conn_pub;
30    enum {
31        HPI_MH_4K       = 1 << 0,
32        HPI_MH_MALLOC   = 1 << 1,
33    }                               hpi_flags;
34    unsigned                        hpi_set[2];         /* Bitmask */
35    unsigned                        hpi_counts[N_HPI_PRIORITIES];   /* For non-incr only */
36    unsigned                        hpi_heaped;         /* Bitmask */
37    struct lsquic_streams_tailq     hpi_streams[2][N_HPI_PRIORITIES];
38    struct min_heap                 hpi_min_heap;
39    /* We do this because http_prio_iter is used in a union with
40     * stream_prio_iter, which is over 4KB on the stack.  Since we
41     * are already allocating this memory on the stack, we might as well
42     * use it.
43     */
44    struct min_heap_elem            hpi_min_heap_els[236];
45};
46
47
48void
49lsquic_hpi_init (void *, struct lsquic_stream *first,
50         struct lsquic_stream *last, uintptr_t next_ptr_offset,
51         struct lsquic_conn_public *, const char *name,
52         int (*filter)(void *filter_ctx, struct lsquic_stream *),
53         void *filter_ctx);
54
55struct lsquic_stream *
56lsquic_hpi_first (void *);
57
58struct lsquic_stream *
59lsquic_hpi_next (void *);
60
61void
62lsquic_hpi_drop_non_high (void *);
63
64void
65lsquic_hpi_drop_high (void *);
66
67void
68lsquic_hpi_cleanup (void *);
69
70#ifndef NDEBUG
71#define LSQUIC_HPI_HEAP_TEST_STACK_OK   (1 << 0)
72#define LSQUIC_HPI_HEAP_TEST_4K_OK      (1 << 1)
73#if LSQUIC_TEST
74void
75lsquic_hpi_set_heap_test (int val);
76#endif
77#endif
78
79#endif
80