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Neither the name of the Chelsio Inc nor the names of its 14.\" contributors may be used to endorse or promote products derived from 15.\" this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18.\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27.\" POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" * Other names and brands may be claimed as the property of others. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd June 16, 2021 34.Dt CRYPTO_BUFFER 9 35.Os 36.Sh NAME 37.Nm crypto_buffer 38.Nd symmetric cryptographic request buffers 39.Sh SYNOPSIS 40.In opencrypto/cryptodev.h 41.Ft int 42.Fo crypto_apply 43.Fa "struct cryptop *crp" 44.Fa "int off" 45.Fa "int len" 46.Fa "int (*f)(void *, void *, u_int)" 47.Fa "void *arg" 48.Fc 49.Ft int 50.Fo crypto_apply_buf 51.Fa "struct crypto_buffer *cb" 52.Fa "int off" 53.Fa "int len" 54.Fa "int (*f)(void *, void *, u_int)" 55.Fa "void *arg" 56.Fc 57.Ft void * 58.Fo crypto_buffer_contiguous_subsegment 59.Fa "struct crypto_buffer *cb" 60.Fa "size_t skip" 61.Fa "size_t len" 62.Fc 63.Ft size_t 64.Fn crypto_buffer_len "struct crypto_buffer *cb" 65.Ft void * 66.Fo crypto_contiguous_subsegment 67.Fa "struct cryptop *crp" 68.Fa "size_t skip" 69.Fa "size_t len" 70.Fc 71.Ft void 72.Fo crypto_cursor_init 73.Fa "struct crypto_buffer_cursor *cc" 74.Fa "const struct crypto_buffer *cb" 75.Fc 76.Ft void 77.Fn crypto_cursor_advance "struct crypto_buffer_cursor *cc" "size_t amount" 78.Ft void 79.Fo crypto_cursor_copyback 80.Fa "struct crypto_buffer_cursor *cc" 81.Fa "int size" 82.Fa "const void *src" 83.Fc 84.Ft void 85.Fo crypto_cursor_copydata 86.Fa "struct crypto_buffer_cursor *cc" 87.Fa "int size" 88.Fa "void *dst" 89.Fc 90.Ft void 91.Fo crypto_cursor_copydata_noadv 92.Fa "struct crypto_buffer_cursor *cc" 93.Fa "int size" 94.Fa "void *dst" 95.Fc 96.Ft void * 97.Fn crypto_cursor_segment "struct crypto_buffer_cursor *cc" "size_t *len" 98.Ft bool 99.Fn CRYPTO_HAS_OUTPUT_BUFFER "struct cryptop *crp" 100.Sh DESCRIPTION 101Symmetric cryptographic requests use data buffers to describe the data to 102be modified. 103Requests can either specify a single data buffer whose contents are modified 104in place, 105or requests may specify separate data buffers for input and output. 106.Vt struct crypto_buffer 107provides an abstraction that permits cryptographic requests to operate on 108different types of buffers. 109.Vt struct crypto_cursor 110allows cryptographic drivers to iterate over a data buffer. 111.Pp 112.Fn CRYPTO_HAS_OUTPUT_BUFFER 113returns true if 114.Fa crp 115uses separate buffers for input and output and false if 116.Fa crp 117uses a single buffer. 118.Pp 119.Fn crypto_buffer_len 120returns the length of data buffer 121.Fa cb 122in bytes. 123.Pp 124.Fn crypto_apply_buf 125invokes a caller-supplied function 126to a region of the data buffer 127.Fa cb . 128The function 129.Fa f 130is called one or more times. 131For each invocation, 132the first argument to 133.Fa f 134is the value of 135.Fa arg 136passed to 137.Fn crypto_apply_buf . 138The second and third arguments to 139.Fa f 140are a pointer and length to a segment of the buffer mapped into the kernel. 141The function is called enough times to cover the 142.Fa len 143bytes of the data buffer which starts at an offset 144.Fa off . 145If any invocation of 146.Fa f 147returns a non-zero value, 148.Fn crypto_apply_buf 149immediately returns that value without invoking 150.Fa f 151on any remaining segments of the region, 152otherwise 153.Fn crypto_apply_buf 154returns the value from the final call to 155.Fa f . 156.Fn crypto_apply 157invokes the callback 158.Fa f 159on a region of the input data buffer for 160.Fa crp . 161.Pp 162.Fn crypto_buffer_contiguous_subsegment 163attempts to locate a single, virtually-contiguous segment of the data buffer 164.Fa cb . 165The segment must be 166.Fa len 167bytes long and start at an offset of 168.Fa skip 169bytes. 170If a segment is found, 171a pointer to the start of the segment is returned. 172Otherwise, 173.Dv NULL 174is returned. 175.Fn crypto_contiguous_subsegment 176attempts to locate a single, virtually-contiguous segment in the input data 177buffer for 178.Fa crp . 179.Ss Data Buffers 180Data buffers are described by an instance of 181.Vt struct crypto buffer . 182The 183.Fa cb_type 184member contains the type of the data buffer. 185The following types are supported: 186.Bl -tag -width " CRYPTO_BUF_CONTIG" 187.It Dv CRYPTO_BUF_NONE 188An invalid buffer. 189Used to mark the output buffer when a crypto request uses a single data buffer. 190.It Dv CRYPTO_BUF_CONTIG 191An array of bytes mapped into the kernel's address space. 192.It Dv CRYPTO_BUF_UIO 193A scatter/gather list of kernel buffers as described in 194.Xr uio 9 . 195.It Dv CRYPTO_BUF_MBUF 196A chain of network memory buffers as described in 197.Xr mbuf 9 . 198.It Dv CRYPTO_BUF_SINGLE_MBUF 199A single network memory buffer as described in 200.Xr mbuf 9 . 201.It Dv CRYPTO_BUF_VMPAGE 202A scatter/gather list of 203.Vt vm_page_t 204structures describing pages in the kernel's address space. 205This buffer type is only available if 206.Dv CRYPTO_HAS_VMPAGE 207is true. 208.El 209.Pp 210The structure also contains the following type-specific fields: 211.Bl -tag -width " cb_vm_page_offset" 212.It Fa cb_buf 213A pointer to the start of a 214.Dv CRYPTO_BUF_CONTIG 215data buffer. 216.It Fa cb_buf_len 217The length of a 218.Dv CRYPTO_BUF_CONTIG 219data buffer 220.It Fa cb_mbuf 221A pointer to a 222.Vt struct mbuf 223for 224.Dv CRYPTO_BUF_MBUF 225and 226.Dv CRYPTO_BUF_SINGLE_MBUF . 227.It Fa cb_uio 228A pointer to a 229.Vt struct uio 230for 231.Dv CRYPTO_BUF_UIO . 232.It Fa cb_vm_page 233A pointer to an array of 234.Vt struct vm_page 235for 236.Dv CRYPTO_BUF_VMPAGE . 237.It Fa cb_vm_page_len 238The total amount of data included in the 239.Fa cb_vm_page 240array, in bytes. 241.It Fa cb_vm_page_offset 242Offset in bytes in the first page of 243.Fa cb_vm_page 244where valid data begins. 245.El 246.Ss Cursors 247Cursors provide a mechanism for iterating over a data buffer. 248They are primarily intended for use in software drivers which access data 249buffers via virtual addresses. 250.Pp 251.Fn crypto_cursor_init 252initializes the cursor 253.Fa cc 254to reference the start of the data buffer 255.Fa cb . 256.Pp 257.Fn crypto_cursor_advance 258advances the cursor 259.Fa amount 260bytes forward in the data buffer. 261.Pp 262.Fn crypto_cursor_copyback 263copies 264.Fa size 265bytes from the local buffer pointed to by 266.Fa src 267into the data buffer associated with 268.Fa cc . 269The bytes are written to the current position of 270.Fa cc , 271and the cursor is then advanced by 272.Fa size 273bytes. 274.Pp 275.Fn crypto_cursor_copydata 276copies 277.Fa size 278bytes out of the data buffer associated with 279.Fa cc 280into a local buffer pointed to by 281.Fa dst . 282The bytes are read from the current position of 283.Fa cc , 284and the cursor is then advanced by 285.Fa size 286bytes. 287.Pp 288.Fn crypto_cursor_copydata_noadv 289is similar to 290.Fn crypto_cursor_copydata 291except that it does not change the current position of 292.Fa cc . 293.Pp 294.Fn crypto_cursor_segment 295returns the start of the virtually-contiguous segment at the current position of 296.Fa cc . 297The length of the segment is stored in 298.Fa len . 299.Sh RETURN VALUES 300.Fn crypto_apply 301and 302.Fn crypto_apply_buf 303return the return value from the caller-supplied callback function. 304.Pp 305.Fn crypto_buffer_contiguous_subsegment , 306.Fn crypto_contiguous_subsegment , 307and 308.Fn crypto_cursor_segment 309return a pointer to a contiguous segment or 310.Dv NULL . 311.Pp 312.Fn crypto_buffer_len 313returns the length of a buffer in bytes. 314.Pp 315.Fn crypto_cursor_seglen 316returns the length in bytes of a contiguous segment. 317.Pp 318.Fn CRYPTO_HAS_OUTPUT_BUFFER 319returns true if the request uses a separate output buffer. 320.Sh SEE ALSO 321.Xr ipsec 4 , 322.Xr crypto 7 , 323.Xr bus_dma 9 , 324.Xr crypto 9 , 325.Xr crypto_driver 9 , 326.Xr crypto_request 9 , 327.Xr crypto_session 9 , 328.Xr mbuf 9 , 329.Xr uio 9 330.Sh HISTORY 331The 332.Nm 333functions first appeared in 334.Fx 13 . 335.Sh AUTHORS 336The 337.Nm 338functions and this manual page were written by 339.An John Baldwin Aq Mt jhb@FreeBSD.org . 340