lsquic_version.c revision b1a7c3f9 
1/* Copyright (c) 2017 - 2020 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#if _MSC_VER
9#include "vc_compat.h"
10#endif
11
12
13static const unsigned char version_tags[N_LSQVER][4] =
14{
15    [LSQVER_043] = { 'Q', '0', '4', '3', },
16    [LSQVER_046] = { 'Q', '0', '4', '6', },
17    [LSQVER_050] = { 'Q', '0', '5', '0', },
18#if LSQUIC_USE_Q098
19    [LSQVER_098] = { 'Q', '0', '9', '8', },
20#endif
21    [LSQVER_ID27] = { 0xFF, 0, 0, 27, },
22    [LSQVER_ID28] = { 0xFF, 0, 0, 28, },
23    [LSQVER_ID29] = { 0xFF, 0, 0, 29, },
24    [LSQVER_ID30] = { 0xFF, 0, 0, 30, },
25    [LSQVER_VERNEG] = { 0xFA, 0xFA, 0xFA, 0xFA, },
26};
27
28
29uint32_t
30lsquic_ver2tag (unsigned version)
31{
32    lsquic_ver_tag_t tag;
33    if (version < N_LSQVER)
34    {
35        memcpy(&tag, version_tags[version], 4);
36        return tag;
37    }
38    else
39        return 0;
40}
41
42
43enum lsquic_version
44lsquic_tag2ver (uint32_t ver_tag)
45{
46    unsigned n;
47    for (n = 0; n < sizeof(version_tags) / sizeof(version_tags[0]); ++n)
48        if (0 == memcmp(version_tags[n], &ver_tag, sizeof(ver_tag)))
49            return n;
50    return -1;
51}
52
53
54const char *const lsquic_ver2str[N_LSQVER] = {
55    [LSQVER_043] = "Q043",
56    [LSQVER_046] = "Q046",
57    [LSQVER_050] = "Q050",
58#if LSQUIC_USE_Q098
59    [LSQVER_098] = "Q098",
60#endif
61    [LSQVER_ID27] = "FF00001B",
62    [LSQVER_ID28] = "FF00001C",
63    [LSQVER_ID29] = "FF00001D",
64    [LSQVER_ID30] = "FF00001E",
65    [LSQVER_VERNEG] = "FAFAFAFA",
66};
67
68
69enum lsquic_version
70lsquic_str2ver (const char *str, size_t len)
71{
72    enum lsquic_version ver;
73    uint32_t tag;
74
75    if (len == sizeof(tag) && 'Q' == str[0])
76    {
77        memcpy(&tag, str, sizeof(tag));
78        return lsquic_tag2ver(tag);
79    }
80
81    for (ver = 0; ver < N_LSQVER; ++ver)
82        if (strlen(lsquic_ver2str[ver]) == len
83            && strncasecmp(lsquic_ver2str[ver], str, len) == 0)
84        {
85            return ver;
86        }
87
88    return -1;
89}
90
91
92int
93lsquic_gen_ver_tags (unsigned char *buf, size_t bufsz, unsigned version_bitmask)
94{
95    unsigned n;
96    lsquic_ver_tag_t tag;
97    unsigned char *p = buf;
98    unsigned char *const pend = p + bufsz;
99    for (n = 0; version_bitmask; ++n)
100    {
101        if (version_bitmask & (1 << n))
102        {
103            if (p + 4 > pend)
104                return -1;
105            version_bitmask &= ~(1 << n);
106            tag = lsquic_ver2tag(n);
107            if (0 == tag)
108                return -1;
109            memcpy(p, &tag, 4);
110            p += 4;
111        }
112    }
113    return p - buf;
114}
115