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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 May 25, 2020 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_segbase "struct crypto_buffer_cursor *cc" 98.Ft size_t 99.Fn crypto_cursor_seglen "struct crypto_buffer_cursor *cc" 100.Ft bool 101.Fn CRYPTO_HAS_OUTPUT_BUFFER "struct cryptop *crp" 102.Sh DESCRIPTION 103Symmetric cryptographic requests use data buffers to describe the data to 104be modified. 105Requests can either specify a single data buffer whose contents are modified 106in place, 107or requests may specify separate data buffers for input and output. 108.Vt struct crypto_buffer 109provides an abstraction that permits cryptographic requests to operate on 110different types of buffers. 111.Vt struct crypto_cursor 112allows cryptographic drivers to iterate over a data buffer. 113.Pp 114.Fn CRYPTO_HAS_OUTPUT_BUFFER 115returns true if 116.Fa crp 117uses separate buffers for input and output and false if 118.Fa crp 119uses a single buffer. 120.Pp 121.Fn crypto_buffer_len 122returns the length of data buffer 123.Fa cb 124in bytes. 125.Pp 126.Fn crypto_apply_buf 127invokes a caller-supplied function 128to a region of the data buffer 129.Fa cb . 130The function 131.Fa f 132is called one or more times. 133For each invocation, 134the first argument to 135.Fa f 136is the value of 137.Fa arg 138passed to 139.Fn crypto_apply_buf . 140The second and third arguments to 141.Fa f 142are a pointer and length to a segment of the buffer mapped into the kernel. 143The function is called enough times to cover the 144.Fa len 145bytes of the data buffer which starts at an offset 146.Fa off . 147If any invocation of 148.Fa f 149returns a non-zero value, 150.Fn crypto_apply_buf 151immediately returns that value without invoking 152.Fa f 153on any remaining segments of the region, 154otherwise 155.Fn crypto_apply_buf 156returns the value from the final call to 157.Fa f . 158.Fn crypto_apply 159invokes the callback 160.Fa f 161on a region of the input data buffer for 162.Fa crp . 163.Pp 164.Fn crypto_buffer_contiguous_subsegment 165attempts to locate a single, virtually-contiguous segment of the data buffer 166.Fa cb . 167The segment must be 168.Fa len 169bytes long and start at an offset of 170.Fa skip 171bytes. 172If a segment is found, 173a pointer to the start of the segment is returned. 174Otherwise, 175.Dv NULL 176is returned. 177.Fn crypto_contiguous_subsegment 178attempts to locate a single, virtually-contiguous segment in the input data 179buffer for 180.Fa crp . 181.Ss Data Buffers 182Data buffers are described by an instance of 183.Vt struct crypto buffer . 184The 185.Fa cb_type 186member contains the type of the data buffer. 187The following types are supported: 188.Bl -tag -width " CRYPTO_BUF_CONTIG" 189.It Dv CRYPTO_BUF_NONE 190An invalid buffer. 191Used to mark the output buffer when a crypto request uses a single data buffer. 192.It Dv CRYPTO_BUF_CONTIG 193An array of bytes mapped into the kernel's address space. 194.It Dv CRYPTO_BUF_UIO 195A scatter/gather list of kernel buffers as described in 196.Xr uio 9 . 197.It Dv CRYPTO_BUF_MBUF 198A network memory buffer as described in 199.Xr mbuf 9 . 200.El 201.Pp 202The structure also contains the following type-specific fields: 203.Bl -tag -width " cb_buf_len" 204.It Fa cb_buf 205A pointer to the start of a 206.Dv CRYPTO_BUF_CONTIG 207data buffer. 208.It Fa cb_buf_len 209The length of a 210.Dv CRYPTO_BUF_CONTIG 211data buffer 212.It Fa cb_mbuf 213A pointer to a 214.Vt struct mbuf 215for 216.Dv CRYPTO_BUF_MBUF . 217.It Fa cb_uio 218A pointer to a 219.Vt struct uio 220for 221.Dv CRYPTO_BUF_UIO . 222.El 223.Ss Cursors 224Cursors provide a mechanism for iterating over a data buffer. 225They are primarily intended for use in software drivers which access data 226buffers via virtual addresses. 227.Pp 228.Fn crypto_cursor_init 229initializes the cursor 230.Fa cc 231to reference the start of the data buffer 232.Fa cb . 233.Pp 234.Fn crypto_cursor_advance 235advances the cursor 236.Fa amount 237bytes forward in the data buffer. 238.Pp 239.Fn crypto_cursor_copyback 240copies 241.Fa size 242bytes from the local buffer pointed to by 243.Fa src 244into the data buffer associated with 245.Fa cc . 246The bytes are written to the current position of 247.Fa cc , 248and the cursor is then advanced by 249.Fa size 250bytes. 251.Pp 252.Fn crypto_cursor_copydata 253copies 254.Fa size 255bytes out of the data buffer associated with 256.Fa cc 257into a local buffer pointed to by 258.Fa dst . 259The bytes are read from the current position of 260.Fa cc , 261and the cursor is then advanced by 262.Fa size 263bytes. 264.Pp 265.Fn crypto_cursor_copydata_noadv 266is similar to 267.Fn crypto_cursor_copydata 268except that it does not change the current position of 269.Fa cc . 270.Pp 271.Fn crypto_cursor_segbase 272and 273.Fn crypto_cursor_seglen 274return the start and length, respectively, 275of the virtually-contiguous segment at the current position of 276.Fa cc . 277.Sh RETURN VALUES 278.Fn crypto_apply 279and 280.Fn crypto_apply_buf 281return the return value from the caller-supplied callback function. 282.Pp 283.Fn crypto_buffer_contiguous_subsegment , 284.Fn crypto_contiguous_subsegment , 285and 286.Fn crypto_cursor_segbase , 287return a pointer to a contiguous segment or 288.Dv NULL . 289.Pp 290.Fn crypto_buffer_len 291returns the length of a buffer in bytes. 292.Pp 293.Fn crypto_cursor_seglen 294returns the length in bytes of a contiguous segment. 295.Pp 296.Fn CRYPTO_HAS_OUTPUT_BUFFER 297returns true if the request uses a separate output buffer. 298.Sh SEE ALSO 299.Xr ipsec 4 , 300.Xr bus_dma 9 , 301.Xr crypto 7 , 302.Xr crypto 9 , 303.Xr crypto_request 9 , 304.Xr crypto_driver 9 , 305.Xr crypto_session 9 , 306.Xr mbuf 9 307.Xr uio 9 308