OpenVPN
occ.h
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1 /*
2  * OpenVPN -- An application to securely tunnel IP networks
3  * over a single TCP/UDP port, with support for SSL/TLS-based
4  * session authentication and key exchange,
5  * packet encryption, packet authentication, and
6  * packet compression.
7  *
8  * Copyright (C) 2002-2021 OpenVPN Inc <sales@openvpn.net>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2
12  * as published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, write to the Free Software Foundation, Inc.,
21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22  */
23 
24 #ifndef OCC_H
25 #define OCC_H
26 
27 #include "forward.h"
28 
29 /* OCC_STRING_SIZE must be set to sizeof (occ_magic) */
30 #define OCC_STRING_SIZE 16
31 
32 /*
33  * OCC (OpenVPN Configuration Control) protocol opcodes.
34  */
35 
36 #define OCC_REQUEST 0 /* request options string from peer */
37 #define OCC_REPLY 1 /* deliver options string to peer */
38 
39 /*
40  * Send an OCC_REQUEST once every OCC_INTERVAL
41  * seconds until a reply is received.
42  *
43  * If we haven't received a reply after
44  * OCC_N_TRIES, give up.
45  */
46 #define OCC_INTERVAL_SECONDS 10
47 #define OCC_N_TRIES 12
48 
49 /*
50  * Other OCC protocol opcodes used to estimate the MTU empirically.
51  */
52 #define OCC_MTU_LOAD_REQUEST 2 /* Ask peer to send a big packet to us */
53 #define OCC_MTU_LOAD 3 /* Send a big packet to peer */
54 #define OCC_MTU_REQUEST 4 /* Ask peer to tell us the largest
55  * packet it has received from us so far */
56 #define OCC_MTU_REPLY 5 /* Send largest packet size to peer */
57 
58 /*
59  * Process one command from mtu_load_test_sequence
60  * once every n seconds, if --mtu-test is specified.
61  */
62 #define OCC_MTU_LOAD_INTERVAL_SECONDS 3
63 
64 /*
65  * Send an exit message to remote.
66  */
67 #define OCC_EXIT 6
68 
69 /*
70  * Used to conduct a load test command sequence
71  * of UDP connection for empirical MTU measurement.
72  */
74 {
75  int op; /* OCC opcode to send to peer */
76  int delta; /* determine packet size to send by using
77  * this delta against currently
78  * configured MTU */
79 };
80 
81 extern const uint8_t occ_magic[];
82 
83 static inline bool
84 is_occ_msg(const struct buffer *buf)
85 {
87 }
88 
89 void process_received_occ_msg(struct context *c);
90 
91 void check_send_occ_req_dowork(struct context *c);
92 
94 
95 void check_send_occ_msg_dowork(struct context *c);
96 
97 /*
98  * Inline functions
99  */
100 
101 static inline int
103 {
104  return -1;
105 }
106 
107 /*
108  * Should we send an OCC_REQUEST message?
109  */
110 static inline void
112 {
115  &c->c2.timeval,
116  (!TO_LINK_DEF(c) && c->c2.occ_op < 0) ? ETT_DEFAULT : 0))
117  {
119  }
120 }
121 
122 /*
123  * Should we send an MTU load test?
124  */
125 static inline void
127 {
130  &c->c2.timeval,
131  (!TO_LINK_DEF(c) && c->c2.occ_op < 0) ? ETT_DEFAULT : 0))
132  {
134  }
135 }
136 
137 /*
138  * Should we send an OCC message?
139  */
140 static inline void
142 {
143  if (c->c2.occ_op >= 0)
144  {
145  if (!TO_LINK_DEF(c))
146  {
148  }
149  else
150  {
151  tv_clear(&c->c2.timeval); /* ZERO-TIMEOUT */
152  }
153  }
154 }
155 
156 #endif /* ifndef OCC_H */
#define ETT_DEFAULT
Definition: interval.h:213
Contains all state information for one tunnel.
Definition: openvpn.h:461
const uint8_t occ_magic[]
Definition: occ.c:57
static bool is_occ_msg(const struct buffer *buf)
Definition: occ.h:84
void process_received_occ_msg(struct context *c)
Definition: occ.c:351
static void tv_clear(struct timeval *tv)
Definition: otime.h:101
static void check_send_occ_load_test(struct context *c)
Definition: occ.h:126
void check_send_occ_load_test_dowork(struct context *c)
Definition: occ.c:186
bool event_timeout_trigger(struct event_timeout *et, struct timeval *tv, const int et_const_retry)
Definition: interval.c:45
struct event_timeout occ_interval
Definition: openvpn.h:297
static int occ_reset_op(void)
Definition: occ.h:102
static bool event_timeout_defined(const struct event_timeout *et)
Definition: interval.h:144
void check_send_occ_req_dowork(struct context *c)
Definition: occ.c:149
struct timeval timeval
Definition: openvpn.h:384
#define TO_LINK_DEF(c)
Definition: forward.h:48
Interface functions to the internal and external multiplexers.
int delta
Definition: occ.h:76
struct context_2 c2
Level 2 context.
Definition: openvpn.h:502
#define OCC_STRING_SIZE
Definition: occ.h:30
static void check_send_occ_req(struct context *c)
Definition: occ.h:111
static void check_send_occ_msg(struct context *c)
Definition: occ.h:141
struct event_timeout occ_mtu_load_test_interval
Definition: openvpn.h:313
void check_send_occ_msg_dowork(struct context *c)
Definition: occ.c:216
static bool buf_string_match_head(const struct buffer *src, const void *match, int size)
Compare first size bytes of src buffer contents with match.
Definition: buffer.h:883
Wrapper structure for dynamically allocated memory.
Definition: buffer.h:60
int op
Definition: occ.h:75
int occ_op
Definition: openvpn.h:295