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1 .\" $OpenBSD: SSL_CTX_set_mode.3,v 1.2 2016/12/01 15:30:23 schwarze Exp $
2 .\" OpenSSL 8671b898 Jun 3 02:48:34 2008 +0000
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52 .Dd $Mdocdate: December 1 2016 $
53 .Dt SSL_CTX_SET_MODE 3
54 .Os
55 .Sh NAME
56 .Nm SSL_CTX_set_mode ,
57 .Nm SSL_set_mode ,
58 .Nm SSL_CTX_get_mode ,
59 .Nm SSL_get_mode
60 .Nd manipulate SSL engine mode
61 .Sh SYNOPSIS
62 .In openssl/ssl.h
63 .Ft long
64 .Fn SSL_CTX_set_mode "SSL_CTX *ctx" "long mode"
65 .Ft long
66 .Fn SSL_set_mode "SSL *ssl" "long mode"
67 .Ft long
68 .Fn SSL_CTX_get_mode "SSL_CTX *ctx"
69 .Ft long
70 .Fn SSL_get_mode "SSL *ssl"
71 .Sh DESCRIPTION
72 .Fn SSL_CTX_set_mode
73 adds the mode set via bitmask in
74 .Fa mode
75 to
76 .Fa ctx .
77 Options already set before are not cleared.
78 .Pp
79 .Fn SSL_set_mode
80 adds the mode set via bitmask in
81 .Fa mode
82 to
83 .Fa ssl .
84 Options already set before are not cleared.
85 .Pp
86 .Fn SSL_CTX_get_mode
87 returns the mode set for
88 .Fa ctx .
89 .Pp
90 .Fn SSL_get_mode
91 returns the mode set for
92 .Fa ssl .
93 .Sh NOTES
94 The following mode changes are available:
95 .Bl -tag -width Ds
96 .It Dv SSL_MODE_ENABLE_PARTIAL_WRITE
97 Allow
98 .Fn SSL_write ... n
99 to return
100 .Ms r
101 with
102 .EQ
103 0 < r < n
104 .EN
105 (i.e., report success when just a single record has been written).
106 When not set (the default),
107 .Xr SSL_write 3
108 will only report success once the complete chunk was written.
109 Once
110 .Xr SSL_write 3
111 returns with
112 .Ms r ,
113 .Ms r
114 bytes have been successfully written and the next call to
115 .Xr SSL_write 3
116 must only send the
117 .Ms n \(mi r
118 bytes left, imitating the behaviour of
119 .Xr write 2 .
120 .It Dv SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER
121 Make it possible to retry
122 .Xr SSL_write 3
123 with changed buffer location (the buffer contents must stay the same).
124 This is not the default to avoid the misconception that non-blocking
125 .Xr SSL_write 3
126 behaves like non-blocking
127 .Xr write 2 .
128 .It Dv SSL_MODE_AUTO_RETRY
129 Never bother the application with retries if the transport is blocking.
130 If a renegotiation take place during normal operation, a
131 .Xr SSL_read 3
132 or
133 .Xr SSL_write 3
134 would return
135 with \(mi1 and indicate the need to retry with
136 .Dv SSL_ERROR_WANT_READ .
137 In a non-blocking environment applications must be prepared to handle
138 incomplete read/write operations.
139 In a blocking environment, applications are not always prepared to deal with
140 read/write operations returning without success report.
141 The flag
142 .Dv SSL_MODE_AUTO_RETRY
143 will cause read/write operations to only return after the handshake and
144 successful completion.
145 .It Dv SSL_MODE_RELEASE_BUFFERS
146 When we no longer need a read buffer or a write buffer for a given
147 .Vt SSL ,
148 then release the memory we were using to hold it.
149 Using this flag can save around 34k per idle SSL connection.
150 This flag has no effect on SSL v2 connections, or on DTLS connections.
151 .El
152 .Sh RETURN VALUES
153 .Fn SSL_CTX_set_mode
154 and
155 .Fn SSL_set_mode
156 return the new mode bitmask after adding
157 .Fa mode .
158 .Pp
159 .Fn SSL_CTX_get_mode
160 and
161 .Fn SSL_get_mode
162 return the current bitmask.
163 .Sh SEE ALSO
164 .Xr ssl 3 ,
165 .Xr SSL_read 3 ,
166 .Xr SSL_write 3
167 .Sh HISTORY
168 .Dv SSL_MODE_AUTO_RETRY
169 was added in OpenSSL 0.9.6.