Index: head/share/man/man9/crypto_buffer.9
===================================================================
--- head/share/man/man9/crypto_buffer.9	(revision 366122)
+++ head/share/man/man9/crypto_buffer.9	(revision 366123)
@@ -1,327 +1,337 @@
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-.Dd August 12, 2020
+.Dd September 24, 2020
 .Dt CRYPTO_BUFFER 9
 .Os
 .Sh NAME
 .Nm crypto_buffer
 .Nd symmetric cryptographic request buffers
 .Sh SYNOPSIS
 .In opencrypto/cryptodev.h
 .Ft int
 .Fo crypto_apply
 .Fa "struct cryptop *crp"
 .Fa "int off"
 .Fa "int len"
 .Fa "int (*f)(void *, void *, u_int)"
 .Fa "void *arg"
 .Fc
 .Ft int
 .Fo crypto_apply_buf
 .Fa "struct crypto_buffer *cb"
 .Fa "int off"
 .Fa "int len"
 .Fa "int (*f)(void *, void *, u_int)"
 .Fa "void *arg"
 .Fc
 .Ft void *
 .Fo crypto_buffer_contiguous_subsegment
 .Fa "struct crypto_buffer *cb"
 .Fa "size_t skip"
 .Fa "size_t len"
 .Fc
 .Ft size_t
 .Fn crypto_buffer_len "struct crypto_buffer *cb"
 .Ft void *
 .Fo crypto_contiguous_subsegment
 .Fa "struct cryptop *crp"
 .Fa "size_t skip"
 .Fa "size_t len"
 .Fc
 .Ft void
 .Fo crypto_cursor_init
 .Fa "struct crypto_buffer_cursor *cc"
 .Fa "const struct crypto_buffer *cb"
 .Fc
 .Ft void
 .Fn crypto_cursor_advance "struct crypto_buffer_cursor *cc" "size_t amount"
 .Ft void
 .Fo crypto_cursor_copyback
 .Fa "struct crypto_buffer_cursor *cc"
 .Fa "int size"
 .Fa "const void *src"
 .Fc
 .Ft void
 .Fo crypto_cursor_copydata
 .Fa "struct crypto_buffer_cursor *cc"
 .Fa "int size"
 .Fa "void *dst"
 .Fc
 .Ft void
 .Fo crypto_cursor_copydata_noadv
 .Fa "struct crypto_buffer_cursor *cc"
 .Fa "int size"
 .Fa "void *dst"
 .Fc
 .Ft void *
 .Fn crypto_cursor_segbase "struct crypto_buffer_cursor *cc"
 .Ft size_t
 .Fn crypto_cursor_seglen "struct crypto_buffer_cursor *cc"
 .Ft bool
 .Fn CRYPTO_HAS_OUTPUT_BUFFER "struct cryptop *crp"
 .Sh DESCRIPTION
 Symmetric cryptographic requests use data buffers to describe the data to
 be modified.
 Requests can either specify a single data buffer whose contents are modified
 in place,
 or requests may specify separate data buffers for input and output.
 .Vt struct crypto_buffer
 provides an abstraction that permits cryptographic requests to operate on
 different types of buffers.
 .Vt struct crypto_cursor
 allows cryptographic drivers to iterate over a data buffer.
 .Pp
 .Fn CRYPTO_HAS_OUTPUT_BUFFER
 returns true if
 .Fa crp
 uses separate buffers for input and output and false if
 .Fa crp
 uses a single buffer.
 .Pp
 .Fn crypto_buffer_len
 returns the length of data buffer
 .Fa cb
 in bytes.
 .Pp
 .Fn crypto_apply_buf
 invokes a caller-supplied function
 to a region of the data buffer
 .Fa cb .
 The function
 .Fa f
 is called one or more times.
 For each invocation,
 the first argument to
 .Fa f
 is the value of
 .Fa arg
 passed to
 .Fn crypto_apply_buf .
 The second and third arguments to
 .Fa f
 are a pointer and length to a segment of the buffer mapped into the kernel.
 The function is called enough times to cover the
 .Fa len
 bytes of the data buffer which starts at an offset
 .Fa off .
 If any invocation of
 .Fa f
 returns a non-zero value,
 .Fn crypto_apply_buf
 immediately returns that value without invoking
 .Fa f
 on any remaining segments of the region,
 otherwise
 .Fn crypto_apply_buf
 returns the value from the final call to
 .Fa f .
 .Fn crypto_apply
 invokes the callback
 .Fa f
 on a region of the input data buffer for
 .Fa crp .
 .Pp
 .Fn crypto_buffer_contiguous_subsegment
 attempts to locate a single, virtually-contiguous segment of the data buffer
 .Fa cb .
 The segment must be
 .Fa len
 bytes long and start at an offset of
 .Fa skip
 bytes.
 If a segment is found,
 a pointer to the start of the segment is returned.
 Otherwise,
 .Dv NULL
 is returned.
 .Fn crypto_contiguous_subsegment
 attempts to locate a single, virtually-contiguous segment in the input data
 buffer for
 .Fa crp .
 .Ss Data Buffers
 Data buffers are described by an instance of
 .Vt struct crypto buffer .
 The
 .Fa cb_type
 member contains the type of the data buffer.
 The following types are supported:
 .Bl -tag -width "  CRYPTO_BUF_CONTIG"
 .It Dv CRYPTO_BUF_NONE
 An invalid buffer.
 Used to mark the output buffer when a crypto request uses a single data buffer.
 .It Dv CRYPTO_BUF_CONTIG
 An array of bytes mapped into the kernel's address space.
 .It Dv CRYPTO_BUF_UIO
 A scatter/gather list of kernel buffers as described in
 .Xr uio 9 .
 .It Dv CRYPTO_BUF_MBUF
 A network memory buffer as described in
 .Xr mbuf 9 .
 .It Dv CRYPTO_BUF_VMPAGE
 A scatter/gather list of
 .Vt vm_page_t
 structures describing pages in the kernel's address space.
 This buffer type is only available if
 .Dv CRYPTO_HAS_VMPAGE
 is true.
 .El
 .Pp
 The structure also contains the following type-specific fields:
 .Bl -tag -width "  cb_vm_page_offset"
 .It Fa cb_buf
 A pointer to the start of a
 .Dv CRYPTO_BUF_CONTIG
 data buffer.
 .It Fa cb_buf_len
 The length of a
 .Dv CRYPTO_BUF_CONTIG
 data buffer
 .It Fa cb_mbuf
 A pointer to a
 .Vt struct mbuf
 for
 .Dv CRYPTO_BUF_MBUF .
 .It Fa cb_uio
 A pointer to a
 .Vt struct uio
 for
 .Dv CRYPTO_BUF_UIO .
 .It Fa cb_vm_page
 A pointer to an array of
 .Vt struct vm_page
 for
 .Dv CRYPTO_BUF_VMPAGE .
 .It Fa cb_vm_page_len
 The total amount of data included in the
 .Fa cb_vm_page
 array, in bytes.
 .It Fa cb_vm_page_offset
 Offset in bytes in the first page of
 .Fa cb_vm_page
 where valid data begins.
 .El
 .Ss Cursors
 Cursors provide a mechanism for iterating over a data buffer.
 They are primarily intended for use in software drivers which access data
 buffers via virtual addresses.
 .Pp
 .Fn crypto_cursor_init
 initializes the cursor
 .Fa cc
 to reference the start of the data buffer
 .Fa cb .
 .Pp
 .Fn crypto_cursor_advance
 advances the cursor
 .Fa amount
 bytes forward in the data buffer.
 .Pp
 .Fn crypto_cursor_copyback
 copies
 .Fa size
 bytes from the local buffer pointed to by
 .Fa src
 into the data buffer associated with
 .Fa cc .
 The bytes are written to the current position of
 .Fa cc ,
 and the cursor is then advanced by
 .Fa size
 bytes.
 .Pp
 .Fn crypto_cursor_copydata
 copies
 .Fa size
 bytes out of the data buffer associated with
 .Fa cc
 into a local buffer pointed to by
 .Fa dst .
 The bytes are read from the current position of
 .Fa cc ,
 and the cursor is then advanced by
 .Fa size
 bytes.
 .Pp
 .Fn crypto_cursor_copydata_noadv
 is similar to
 .Fn crypto_cursor_copydata
 except that it does not change the current position of
 .Fa cc .
 .Pp
 .Fn crypto_cursor_segbase
 and
 .Fn crypto_cursor_seglen
 return the start and length, respectively,
 of the virtually-contiguous segment at the current position of
 .Fa cc .
 .Sh RETURN VALUES
 .Fn crypto_apply
 and
 .Fn crypto_apply_buf
 return the return value from the caller-supplied callback function.
 .Pp
 .Fn crypto_buffer_contiguous_subsegment ,
 .Fn crypto_contiguous_subsegment ,
 and
 .Fn crypto_cursor_segbase ,
 return a pointer to a contiguous segment or
 .Dv NULL .
 .Pp
 .Fn crypto_buffer_len
 returns the length of a buffer in bytes.
 .Pp
 .Fn crypto_cursor_seglen
 returns the length in bytes of a contiguous segment.
 .Pp
 .Fn CRYPTO_HAS_OUTPUT_BUFFER
 returns true if the request uses a separate output buffer.
 .Sh SEE ALSO
 .Xr ipsec 4 ,
 .Xr crypto 7 ,
 .Xr bus_dma 9 ,
 .Xr crypto 9 ,
 .Xr crypto_driver 9 ,
 .Xr crypto_request 9 ,
 .Xr crypto_session 9 ,
 .Xr mbuf 9 ,
 .Xr uio 9
+.Sh HISTORY
+The
+.Nm
+functions first appeared in
+.Fx 13 .
+.Sh AUTHORS
+The
+.Nm
+functions and this manual page were written by
+.An John Baldwin Aq Mt jhb@FreeBSD.org .