1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/*
* ngtcp2
*
* Copyright (c) 2022 ngtcp2 contributors
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "ngtcp2_pmtud.h"
#include <assert.h>
#include "ngtcp2_mem.h"
#include "ngtcp2_macro.h"
/* NGTCP2_PMTUD_PROBE_NUM_MAX is the maximum number of packets sent
for each probe. */
#define NGTCP2_PMTUD_PROBE_NUM_MAX 3
static uint16_t pmtud_default_probes[] = {
1454 - 48, /* The well known MTU used by a domestic optic fiber
service in Japan. */
1390 - 48, /* Typical Tunneled MTU */
1280 - 48, /* IPv6 minimum MTU */
1492 - 48, /* PPPoE */
};
int ngtcp2_pmtud_new(ngtcp2_pmtud **ppmtud, size_t max_udp_payload_size,
size_t hard_max_udp_payload_size, int64_t tx_pkt_num,
const uint16_t *probes, size_t probeslen,
const ngtcp2_mem *mem) {
ngtcp2_pmtud *pmtud = ngtcp2_mem_malloc(mem, sizeof(ngtcp2_pmtud));
if (pmtud == NULL) {
return NGTCP2_ERR_NOMEM;
}
pmtud->mem = mem;
pmtud->mtu_idx = 0;
pmtud->num_pkts_sent = 0;
pmtud->expiry = UINT64_MAX;
pmtud->tx_pkt_num = tx_pkt_num;
pmtud->max_udp_payload_size = max_udp_payload_size;
pmtud->hard_max_udp_payload_size = hard_max_udp_payload_size;
pmtud->min_fail_udp_payload_size = SIZE_MAX;
if (probeslen) {
pmtud->probes = probes;
pmtud->probeslen = probeslen;
} else {
pmtud->probes = pmtud_default_probes;
pmtud->probeslen = ngtcp2_arraylen(pmtud_default_probes);
}
for (; pmtud->mtu_idx < pmtud->probeslen; ++pmtud->mtu_idx) {
if (pmtud->probes[pmtud->mtu_idx] > pmtud->hard_max_udp_payload_size) {
continue;
}
if (pmtud->probes[pmtud->mtu_idx] > pmtud->max_udp_payload_size) {
break;
}
}
*ppmtud = pmtud;
return 0;
}
void ngtcp2_pmtud_del(ngtcp2_pmtud *pmtud) {
if (!pmtud) {
return;
}
ngtcp2_mem_free(pmtud->mem, pmtud);
}
size_t ngtcp2_pmtud_probelen(ngtcp2_pmtud *pmtud) {
assert(pmtud->mtu_idx < pmtud->probeslen);
return pmtud->probes[pmtud->mtu_idx];
}
void ngtcp2_pmtud_probe_sent(ngtcp2_pmtud *pmtud, ngtcp2_duration pto,
ngtcp2_tstamp ts) {
ngtcp2_tstamp timeout;
if (++pmtud->num_pkts_sent < NGTCP2_PMTUD_PROBE_NUM_MAX) {
timeout = pto;
} else {
timeout = 3 * pto;
}
pmtud->expiry = ts + timeout;
}
int ngtcp2_pmtud_require_probe(ngtcp2_pmtud *pmtud) {
return pmtud->expiry == UINT64_MAX;
}
static void pmtud_next_probe(ngtcp2_pmtud *pmtud) {
assert(pmtud->mtu_idx < pmtud->probeslen);
++pmtud->mtu_idx;
pmtud->num_pkts_sent = 0;
pmtud->expiry = UINT64_MAX;
for (; pmtud->mtu_idx < pmtud->probeslen; ++pmtud->mtu_idx) {
if (pmtud->probes[pmtud->mtu_idx] <= pmtud->max_udp_payload_size ||
pmtud->probes[pmtud->mtu_idx] > pmtud->hard_max_udp_payload_size) {
continue;
}
if (pmtud->probes[pmtud->mtu_idx] < pmtud->min_fail_udp_payload_size) {
break;
}
}
}
void ngtcp2_pmtud_probe_success(ngtcp2_pmtud *pmtud, size_t payloadlen) {
pmtud->max_udp_payload_size =
ngtcp2_max_size(pmtud->max_udp_payload_size, payloadlen);
assert(pmtud->mtu_idx < pmtud->probeslen);
if (pmtud->probes[pmtud->mtu_idx] > pmtud->max_udp_payload_size) {
return;
}
pmtud_next_probe(pmtud);
}
void ngtcp2_pmtud_handle_expiry(ngtcp2_pmtud *pmtud, ngtcp2_tstamp ts) {
if (ts < pmtud->expiry) {
return;
}
pmtud->expiry = UINT64_MAX;
if (pmtud->num_pkts_sent < NGTCP2_PMTUD_PROBE_NUM_MAX) {
return;
}
pmtud->min_fail_udp_payload_size = ngtcp2_min_size(
pmtud->min_fail_udp_payload_size, pmtud->probes[pmtud->mtu_idx]);
pmtud_next_probe(pmtud);
}
int ngtcp2_pmtud_finished(ngtcp2_pmtud *pmtud) {
return pmtud->mtu_idx >= pmtud->probeslen;
}
|
