lsquic_hpi.h revision fbc6cc04 
1/* Copyright (c) 2017 - 2020 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
14struct lsquic_conn_public;
15
16/* We add 1 to the urgency when we place them on hpi_streams.  Critical
17 * streams get the highest-priority slot zero.
18 */
19#define N_HPI_PRIORITIES (2 + LSQUIC_MAX_HTTP_URGENCY)
20
21
22struct http_prio_iter
23{
24    const char                     *hpi_name;           /* Used for logging */
25    struct lsquic_conn_public      *hpi_conn_pub;
26    enum {
27        HPI_MH_4K       = 1 << 0,
28        HPI_MH_MALLOC   = 1 << 1,
29    }                               hpi_flags;
30    unsigned                        hpi_set[2];         /* Bitmask */
31    unsigned                        hpi_counts[N_HPI_PRIORITIES];   /* For non-incr only */
32    unsigned                        hpi_heaped;         /* Bitmask */
33    struct lsquic_streams_tailq     hpi_streams[2][N_HPI_PRIORITIES];
34    struct min_heap                 hpi_min_heap;
35    /* We do this because http_prio_iter is used in a union with
36     * stream_prio_iter, which is over 4KB on the stack.  Since we
37     * are already allocating this memory on the stack, we might as well
38     * use it.
39     */
40    struct min_heap_elem            hpi_min_heap_els[236];
41};
42
43
44void
45lsquic_hpi_init (void *, struct lsquic_stream *first,
46         struct lsquic_stream *last, uintptr_t next_ptr_offset,
47         struct lsquic_conn_public *, const char *name,
48         int (*filter)(void *filter_ctx, struct lsquic_stream *),
49         void *filter_ctx);
50
51struct lsquic_stream *
52lsquic_hpi_first (void *);
53
54struct lsquic_stream *
55lsquic_hpi_next (void *);
56
57void
58lsquic_hpi_drop_non_high (void *);
59
60void
61lsquic_hpi_drop_high (void *);
62
63void
64lsquic_hpi_cleanup (void *);
65
66#ifndef NDEBUG
67#define LSQUIC_HPI_HEAP_TEST_STACK_OK   (1 << 0)
68#define LSQUIC_HPI_HEAP_TEST_4K_OK      (1 << 1)
69#if LSQUIC_TEST
70void
71lsquic_hpi_set_heap_test (int val);
72#endif
73#endif
74
75#endif
76