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
|
=pod
=head1 NAME
SSL_CTX_set_info_callback, SSL_CTX_get_info_callback, SSL_set_info_callback, SSL_get_info_callback - handle information callback for SSL connections
=head1 SYNOPSIS
#include <openssl/ssl.h>
void SSL_CTX_set_info_callback(SSL_CTX *ctx, void (*callback)());
void (*SSL_CTX_get_info_callback(const SSL_CTX *ctx))();
void SSL_set_info_callback(SSL *ssl, void (*callback)());
void (*SSL_get_info_callback(const SSL *ssl))();
=head1 DESCRIPTION
SSL_CTX_set_info_callback() sets the B<callback> function, that can be used to
obtain state information for SSL objects created from B<ctx> during connection
setup and use. The setting for B<ctx> is overridden from the setting for
a specific SSL object, if specified.
When B<callback> is NULL, not callback function is used.
SSL_set_info_callback() sets the B<callback> function, that can be used to
obtain state information for B<ssl> during connection setup and use.
When B<callback> is NULL, the callback setting currently valid for
B<ctx> is used.
SSL_CTX_get_info_callback() returns a pointer to the currently set information
callback function for B<ctx>.
SSL_get_info_callback() returns a pointer to the currently set information
callback function for B<ssl>.
=head1 NOTES
When setting up a connection and during use, it is possible to obtain state
information from the SSL/TLS engine. When set, an information callback function
is called whenever the state changes, an alert appears, or an error occurs.
The callback function is called as B<callback(SSL *ssl, int where, int ret)>.
The B<where> argument specifies information about where (in which context)
the callback function was called. If B<ret> is 0, an error condition occurred.
If an alert is handled, SSL_CB_ALERT is set and B<ret> specifies the alert
information.
B<where> is a bitmask made up of the following bits:
=over 4
=item SSL_CB_LOOP
Callback has been called to indicate state change inside a loop.
=item SSL_CB_EXIT
Callback has been called to indicate error exit of a handshake function.
(May be soft error with retry option for non-blocking setups.)
=item SSL_CB_READ
Callback has been called during read operation.
=item SSL_CB_WRITE
Callback has been called during write operation.
=item SSL_CB_ALERT
Callback has been called due to an alert being sent or received.
=item SSL_CB_READ_ALERT (SSL_CB_ALERT|SSL_CB_READ)
=item SSL_CB_WRITE_ALERT (SSL_CB_ALERT|SSL_CB_WRITE)
=item SSL_CB_ACCEPT_LOOP (SSL_ST_ACCEPT|SSL_CB_LOOP)
=item SSL_CB_ACCEPT_EXIT (SSL_ST_ACCEPT|SSL_CB_EXIT)
=item SSL_CB_CONNECT_LOOP (SSL_ST_CONNECT|SSL_CB_LOOP)
=item SSL_CB_CONNECT_EXIT (SSL_ST_CONNECT|SSL_CB_EXIT)
=item SSL_CB_HANDSHAKE_START
Callback has been called because a new handshake is started.
=item SSL_CB_HANDSHAKE_DONE 0x20
Callback has been called because a handshake is finished.
=back
The current state information can be obtained using the
L<SSL_state_string(3)|SSL_state_string(3)> family of functions.
The B<ret> information can be evaluated using the
L<SSL_alert_type_string(3)|SSL_alert_type_string(3)> family of functions.
=head1 RETURN VALUES
SSL_set_info_callback() does not provide diagnostic information.
SSL_get_info_callback() returns the current setting.
=head1 EXAMPLES
The following example callback function prints state strings, information
about alerts being handled and error messages to the B<bio_err> BIO.
void apps_ssl_info_callback(SSL *s, int where, int ret)
{
const char *str;
int w;
w=where& ~SSL_ST_MASK;
if (w & SSL_ST_CONNECT) str="SSL_connect";
else if (w & SSL_ST_ACCEPT) str="SSL_accept";
else str="undefined";
if (where & SSL_CB_LOOP)
{
BIO_printf(bio_err,"%s:%s\n",str,SSL_state_string_long(s));
}
else if (where & SSL_CB_ALERT)
{
str=(where & SSL_CB_READ)?"read":"write";
BIO_printf(bio_err,"SSL3 alert %s:%s:%s\n",
str,
SSL_alert_type_string_long(ret),
SSL_alert_desc_string_long(ret));
}
else if (where & SSL_CB_EXIT)
{
if (ret == 0)
BIO_printf(bio_err,"%s:failed in %s\n",
str,SSL_state_string_long(s));
else if (ret < 0)
{
BIO_printf(bio_err,"%s:error in %s\n",
str,SSL_state_string_long(s));
}
}
}
=head1 SEE ALSO
L<ssl(3)|ssl(3)>, L<SSL_state_string(3)|SSL_state_string(3)>,
L<SSL_alert_type_string(3)|SSL_alert_type_string(3)>
=cut
|
