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33 .Dd September 24, 2020
38 .Nd symmetric cryptographic request buffers
40 .In opencrypto/cryptodev.h
43 .Fa "struct cryptop *crp"
46 .Fa "int (*f)(void *, void *, u_int)"
51 .Fa "struct crypto_buffer *cb"
54 .Fa "int (*f)(void *, void *, u_int)"
58 .Fo crypto_buffer_contiguous_subsegment
59 .Fa "struct crypto_buffer *cb"
64 .Fn crypto_buffer_len "struct crypto_buffer *cb"
66 .Fo crypto_contiguous_subsegment
67 .Fa "struct cryptop *crp"
72 .Fo crypto_cursor_init
73 .Fa "struct crypto_buffer_cursor *cc"
74 .Fa "const struct crypto_buffer *cb"
77 .Fn crypto_cursor_advance "struct crypto_buffer_cursor *cc" "size_t amount"
79 .Fo crypto_cursor_copyback
80 .Fa "struct crypto_buffer_cursor *cc"
85 .Fo crypto_cursor_copydata
86 .Fa "struct crypto_buffer_cursor *cc"
91 .Fo crypto_cursor_copydata_noadv
92 .Fa "struct crypto_buffer_cursor *cc"
97 .Fn crypto_cursor_segbase "struct crypto_buffer_cursor *cc"
99 .Fn crypto_cursor_seglen "struct crypto_buffer_cursor *cc"
101 .Fn CRYPTO_HAS_OUTPUT_BUFFER "struct cryptop *crp"
103 Symmetric cryptographic requests use data buffers to describe the data to
105 Requests can either specify a single data buffer whose contents are modified
107 or requests may specify separate data buffers for input and output.
108 .Vt struct crypto_buffer
109 provides an abstraction that permits cryptographic requests to operate on
110 different types of buffers.
111 .Vt struct crypto_cursor
112 allows cryptographic drivers to iterate over a data buffer.
114 .Fn CRYPTO_HAS_OUTPUT_BUFFER
117 uses separate buffers for input and output and false if
119 uses a single buffer.
121 .Fn crypto_buffer_len
122 returns the length of data buffer
127 invokes a caller-supplied function
128 to a region of the data buffer
132 is called one or more times.
134 the first argument to
139 .Fn crypto_apply_buf .
140 The second and third arguments to
142 are a pointer and length to a segment of the buffer mapped into the kernel.
143 The function is called enough times to cover the
145 bytes of the data buffer which starts at an offset
149 returns a non-zero value,
151 immediately returns that value without invoking
153 on any remaining segments of the region,
156 returns the value from the final call to
161 on a region of the input data buffer for
164 .Fn crypto_buffer_contiguous_subsegment
165 attempts to locate a single, virtually-contiguous segment of the data buffer
169 bytes long and start at an offset of
172 If a segment is found,
173 a pointer to the start of the segment is returned.
177 .Fn crypto_contiguous_subsegment
178 attempts to locate a single, virtually-contiguous segment in the input data
182 Data buffers are described by an instance of
183 .Vt struct crypto buffer .
186 member contains the type of the data buffer.
187 The following types are supported:
188 .Bl -tag -width " CRYPTO_BUF_CONTIG"
189 .It Dv CRYPTO_BUF_NONE
191 Used to mark the output buffer when a crypto request uses a single data buffer.
192 .It Dv CRYPTO_BUF_CONTIG
193 An array of bytes mapped into the kernel's address space.
194 .It Dv CRYPTO_BUF_UIO
195 A scatter/gather list of kernel buffers as described in
197 .It Dv CRYPTO_BUF_MBUF
198 A network memory buffer as described in
200 .It Dv CRYPTO_BUF_VMPAGE
201 A scatter/gather list of
203 structures describing pages in the kernel's address space.
204 This buffer type is only available if
205 .Dv CRYPTO_HAS_VMPAGE
209 The structure also contains the following type-specific fields:
210 .Bl -tag -width " cb_vm_page_offset"
212 A pointer to the start of a
213 .Dv CRYPTO_BUF_CONTIG
217 .Dv CRYPTO_BUF_CONTIG
223 .Dv CRYPTO_BUF_MBUF .
230 A pointer to an array of
233 .Dv CRYPTO_BUF_VMPAGE .
234 .It Fa cb_vm_page_len
235 The total amount of data included in the
238 .It Fa cb_vm_page_offset
239 Offset in bytes in the first page of
241 where valid data begins.
244 Cursors provide a mechanism for iterating over a data buffer.
245 They are primarily intended for use in software drivers which access data
246 buffers via virtual addresses.
248 .Fn crypto_cursor_init
249 initializes the cursor
251 to reference the start of the data buffer
254 .Fn crypto_cursor_advance
257 bytes forward in the data buffer.
259 .Fn crypto_cursor_copyback
262 bytes from the local buffer pointed to by
264 into the data buffer associated with
266 The bytes are written to the current position of
268 and the cursor is then advanced by
272 .Fn crypto_cursor_copydata
275 bytes out of the data buffer associated with
277 into a local buffer pointed to by
279 The bytes are read from the current position of
281 and the cursor is then advanced by
285 .Fn crypto_cursor_copydata_noadv
287 .Fn crypto_cursor_copydata
288 except that it does not change the current position of
291 .Fn crypto_cursor_segbase
293 .Fn crypto_cursor_seglen
294 return the start and length, respectively,
295 of the virtually-contiguous segment at the current position of
301 return the return value from the caller-supplied callback function.
303 .Fn crypto_buffer_contiguous_subsegment ,
304 .Fn crypto_contiguous_subsegment ,
306 .Fn crypto_cursor_segbase ,
307 return a pointer to a contiguous segment or
310 .Fn crypto_buffer_len
311 returns the length of a buffer in bytes.
313 .Fn crypto_cursor_seglen
314 returns the length in bytes of a contiguous segment.
316 .Fn CRYPTO_HAS_OUTPUT_BUFFER
317 returns true if the request uses a separate output buffer.
323 .Xr crypto_driver 9 ,
324 .Xr crypto_request 9 ,
325 .Xr crypto_session 9 ,
331 functions first appeared in
336 functions and this manual page were written by
337 .An John Baldwin Aq Mt jhb@FreeBSD.org .