lsquic_conn_flow.h revision 50aadb33 
1/* Copyright (c) 2017 LiteSpeed Technologies Inc.  See LICENSE. */
2/*
3 * lsquic_conn_flow.h -- Connection flow control-related functions
4 */
5
6#ifndef LSQUIC_CONN_FLOW_H
7#define LSQUIC_CONN_FLOW_H 1
8
9struct lsquic_conn_public;
10
11typedef struct lsquic_cfcw {
12    struct lsquic_conn_public
13                 *cf_conn_pub;
14    uint64_t      cf_max_recv_off;  /* Largest offset observed (cumulative) */
15    uint64_t      cf_recv_off;      /* Flow control receive offset */
16    uint64_t      cf_read_off;      /* Number of bytes consumed (cumulative) */
17    lsquic_time_t cf_last_updated;
18    unsigned      cf_max_recv_win;  /* Maximum receive window */
19} lsquic_cfcw_t;
20
21struct lsquic_conn_cap {
22    uint64_t cc_sent;           /* Number of bytes sent on connection */
23    uint64_t cc_max;            /* Maximum cumulative number of bytes allowed
24                                 * to be sent on this connection.
25                                 */
26    uint64_t cc_tosend;         /* Number of bytes scheduled to be sent
27                                 * accross all streams.
28                                 */
29    uint64_t cc_blocked;        /* Last blocked offset used */
30};
31
32
33#define lsquic_conn_cap_init(cc, max) do {                          \
34    (cc)->cc_sent = 0;                                              \
35    (cc)->cc_tosend = 0;                                            \
36    (cc)->cc_max = max;                                             \
37} while (0)
38
39
40#define lsquic_conn_cap_avail(cap) (                                \
41    ((cap)->cc_sent + (cap)->cc_tosend <= (cap)->cc_max)            \
42    ?                                                               \
43        ((cap)->cc_max - (cap)->cc_sent - (cap)->cc_tosend)         \
44    :                                                               \
45        0                                                           \
46)
47
48
49void
50lsquic_cfcw_init (lsquic_cfcw_t *, struct lsquic_conn_public *,
51                                        unsigned initial_max_recv_window);
52
53/* If update is to be sent, updates max_recv_off and returns true.  Note
54 * that if you call this function twice, the second call will return false.
55 */
56int
57lsquic_cfcw_fc_offsets_changed (lsquic_cfcw_t *);
58
59#define lsquic_cfcw_get_fc_recv_off(fc) (+(fc)->cf_recv_off)
60
61#define lsquic_cfcw_get_max_recv_off(fc) (+(fc)->cf_max_recv_off)
62
63#define lsquic_cfcw_get_max_recv_window(fc) (+(fc)->cf_max_recv_win)
64
65/* Returns false if flow control violation is encountered */
66int
67lsquic_cfcw_incr_max_recv_off (lsquic_cfcw_t *, uint64_t);
68
69/* Void because we do not expect the caller to make a mistake.
70 */
71void
72lsquic_cfcw_incr_read_off (lsquic_cfcw_t *, uint64_t);
73
74#endif
75