lsquic_version.c revision 97028223 
1/* Copyright (c) 2017 - 2018 LiteSpeed Technologies Inc.  See LICENSE. */
2#include <string.h>
3
4#include "lsquic.h"
5#include "lsquic_int_types.h"
6#include "lsquic_version.h"
7
8
9static const unsigned char version_tags[N_LSQVER][4] =
10{
11    [LSQVER_035] = { 'Q', '0', '3', '5', },
12    [LSQVER_039] = { 'Q', '0', '3', '9', },
13    [LSQVER_043] = { 'Q', '0', '4', '3', },
14};
15
16
17uint32_t
18lsquic_ver2tag (unsigned version)
19{
20    lsquic_ver_tag_t tag;
21    if (version < N_LSQVER)
22    {
23        memcpy(&tag, version_tags[version], 4);
24        return tag;
25    }
26    else
27        return 0;
28}
29
30
31enum lsquic_version
32lsquic_tag2ver (uint32_t ver_tag)
33{
34    unsigned n;
35    for (n = 0; n < sizeof(version_tags) / sizeof(version_tags[0]); ++n)
36        if (0 == memcmp(version_tags[n], &ver_tag, sizeof(ver_tag)))
37            return n;
38    return -1;
39}
40
41
42enum lsquic_version
43lsquic_str2ver (const char *str, size_t len)
44{
45    uint32_t tag;
46
47    if (len == sizeof(tag) && 'Q' == str[0])
48    {
49        memcpy(&tag, str, sizeof(tag));
50        return lsquic_tag2ver(tag);
51    }
52    else
53        return -1;
54}
55
56
57const char *const lsquic_ver2str[N_LSQVER] = {
58    [LSQVER_035] = "Q035",
59    [LSQVER_039] = "Q039",
60    [LSQVER_043] = "Q043",
61};
62
63
64int
65gen_ver_tags (unsigned char *buf, size_t bufsz, unsigned version_bitmask)
66{
67    unsigned n;
68    lsquic_ver_tag_t tag;
69    unsigned char *p = buf;
70    unsigned char *const pend = p + bufsz;
71    for (n = 0; version_bitmask; ++n)
72    {
73        if (version_bitmask & (1 << n))
74        {
75            if (p + 4 > pend)
76                return -1;
77            version_bitmask &= ~(1 << n);
78            tag = lsquic_ver2tag(n);
79            if (0 == tag)
80                return -1;
81            memcpy(p, &tag, 4);
82            p += 4;
83        }
84    }
85    return p - buf;
86}
87