- import of strongswan-2.7.0
- applied patch for charon
This commit is contained in:
Martin Willi
@@ -0,0 +1,277 @@
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.\"
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.\" Copyright (C) 2000, 2001 Internet Software Consortium.
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.\"
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.\" Permission to use, copy, modify, and distribute this software for any
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" copyright notice and this permission notice appear in all copies.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
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.\" DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
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.\" INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
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.\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
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.\" FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.TH "LWRES_BUFFER" "3" "Jun 30, 2000" "BIND9" ""
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.SH NAME
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lwres_buffer_init, lwres_buffer_invalidate, lwres_buffer_add, lwres_buffer_subtract, lwres_buffer_clear, lwres_buffer_first, lwres_buffer_forward, lwres_buffer_back, lwres_buffer_getuint8, lwres_buffer_putuint8, lwres_buffer_getuint16, lwres_buffer_putuint16, lwres_buffer_getuint32, lwres_buffer_putuint32, lwres_buffer_putmem, lwres_buffer_getmem \- lightweight resolver buffer management
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.SH SYNOPSIS
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\fB#include <lwres/lwbuffer.h>
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.sp
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.na
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void
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lwres_buffer_init(lwres_buffer_t *b, void *base, unsigned int length);
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.ad
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.sp
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.na
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void
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lwres_buffer_invalidate(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_add(lwres_buffer_t *b, unsigned int n);
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.ad
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.sp
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.na
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void
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lwres_buffer_subtract(lwres_buffer_t *b, unsigned int n);
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.ad
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.sp
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.na
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void
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lwres_buffer_clear(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_first(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_forward(lwres_buffer_t *b, unsigned int n);
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.ad
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.sp
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.na
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void
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lwres_buffer_back(lwres_buffer_t *b, unsigned int n);
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.ad
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.sp
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.na
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lwres_uint8_t
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lwres_buffer_getuint8(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_putuint8(lwres_buffer_t *b, lwres_uint8_t val);
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.ad
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.sp
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.na
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lwres_uint16_t
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lwres_buffer_getuint16(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_putuint16(lwres_buffer_t *b, lwres_uint16_t val);
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.ad
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.sp
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.na
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lwres_uint32_t
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lwres_buffer_getuint32(lwres_buffer_t *b);
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.ad
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.sp
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.na
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void
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lwres_buffer_putuint32(lwres_buffer_t *b, lwres_uint32_t val);
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.ad
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.sp
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.na
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void
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lwres_buffer_putmem(lwres_buffer_t *b, const unsigned char *base, unsigned int length);
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.ad
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.sp
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.na
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void
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lwres_buffer_getmem(lwres_buffer_t *b, unsigned char *base, unsigned int length);
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.ad
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\fR.SH "DESCRIPTION"
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.PP
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These functions provide bounds checked access to a region of memory
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where data is being read or written.
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They are based on, and similar to, the
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isc_buffer_
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functions in the ISC library.
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.PP
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A buffer is a region of memory, together with a set of related
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subregions.
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The \fBused region\fR and the
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\fBavailable\fR region are disjoint, and
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their union is the buffer's region.
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The used region extends from the beginning of the buffer region to the
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last used byte.
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The available region extends from one byte greater than the last used
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byte to the end of the buffer's region.
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The size of the used region can be changed using various
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buffer commands.
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Initially, the used region is empty.
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.PP
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The used region is further subdivided into two disjoint regions: the
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\fBconsumed region\fR and the \fBremaining region\fR.
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The union of these two regions is the used region.
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The consumed region extends from the beginning of the used region to
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the byte before the \fBcurrent\fR offset (if any).
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The \fBremaining\fR region the current pointer to the end of the used
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region.
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The size of the consumed region can be changed using various
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buffer commands.
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Initially, the consumed region is empty.
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.PP
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The \fBactive region\fR is an (optional) subregion of the remaining
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region.
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It extends from the current offset to an offset in the
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remaining region.
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Initially, the active region is empty.
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If the current offset advances beyond the chosen offset,
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the active region will also be empty.
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.PP
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.sp
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.nf
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/------------entire length---------------\\\\
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/----- used region -----\\\\/-- available --\\\\
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+----------------------------------------+
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| consumed | remaining | |
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+----------------------------------------+
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a b c d e
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a == base of buffer.
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b == current pointer. Can be anywhere between a and d.
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c == active pointer. Meaningful between b and d.
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d == used pointer.
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e == length of buffer.
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a-e == entire length of buffer.
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a-d == used region.
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a-b == consumed region.
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b-d == remaining region.
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b-c == optional active region.
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.sp
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.fi
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.PP
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\fBlwres_buffer_init()\fR
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initializes the
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\fBlwres_buffer_t\fR
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\fI*b\fR
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and assocates it with the memory region of size
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\fIlength\fR
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bytes starting at location
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\fIbase.\fR
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.PP
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\fBlwres_buffer_invalidate()\fR
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marks the buffer
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\fI*b\fR
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as invalid. Invalidating a buffer after use is not required,
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but makes it possible to catch its possible accidental use.
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.PP
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The functions
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\fBlwres_buffer_add()\fR
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and
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\fBlwres_buffer_subtract()\fR
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respectively increase and decrease the used space in
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buffer
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\fI*b\fR
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by
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\fIn\fR
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bytes.
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\fBlwres_buffer_add()\fR
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checks for buffer overflow and
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\fBlwres_buffer_subtract()\fR
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checks for underflow.
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These functions do not allocate or deallocate memory.
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They just change the value of
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\fBused\fR.
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.PP
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A buffer is re-initialised by
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\fBlwres_buffer_clear()\fR.
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The function sets
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\fBused\fR ,
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\fBcurrent\fR
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and
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\fBactive\fR
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to zero.
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.PP
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\fBlwres_buffer_first\fR
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makes the consumed region of buffer
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\fI*p\fR
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empty by setting
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\fBcurrent\fR
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to zero (the start of the buffer).
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.PP
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\fBlwres_buffer_forward()\fR
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increases the consumed region of buffer
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\fI*b\fR
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by
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\fIn\fR
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bytes, checking for overflow.
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Similarly,
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\fBlwres_buffer_back()\fR
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decreases buffer
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\fIb\fR's
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consumed region by
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\fIn\fR
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bytes and checks for underflow.
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.PP
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\fBlwres_buffer_getuint8()\fR
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reads an unsigned 8-bit integer from
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\fI*b\fR
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and returns it.
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\fBlwres_buffer_putuint8()\fR
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writes the unsigned 8-bit integer
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\fIval\fR
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to buffer
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\fI*b\fR.
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.PP
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\fBlwres_buffer_getuint16()\fR
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and
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\fBlwres_buffer_getuint32()\fR
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are identical to
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\fBlwres_buffer_putuint8()\fR
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except that they respectively read an unsigned 16-bit or 32-bit integer
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in network byte order from
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\fIb\fR.
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Similarly,
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\fBlwres_buffer_putuint16()\fR
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and
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\fBlwres_buffer_putuint32()\fR
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writes the unsigned 16-bit or 32-bit integer
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\fIval\fR
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to buffer
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\fIb\fR,
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in network byte order.
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.PP
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Arbitrary amounts of data are read or written from a lightweight
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resolver buffer with
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\fBlwres_buffer_getmem()\fR
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and
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\fBlwres_buffer_putmem()\fR
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respectively.
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\fBlwres_buffer_putmem()\fR
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copies
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\fIlength\fR
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bytes of memory at
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\fIbase\fR
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to
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\fIb\fR.
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Conversely,
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\fBlwres_buffer_getmem()\fR
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copies
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\fIlength\fR
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bytes of memory from
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\fIb\fR
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to
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\fIbase\fR.
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