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[Settings] Migrate DHCP and NVO code to the new settings API (untested)

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This commit is contained in:
Michael Brown
2008-03-21 22:15:31 +00:00
parent bb32b8999c
commit 8afb36c3bc
16 changed files with 966 additions and 936 deletions
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468
src/net/dhcpopts.c
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@@ -1,5 +1,5 @@
/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
* Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@@ -19,14 +19,10 @@
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <byteswap.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <gpxe/list.h>
#include <gpxe/in.h>
#include <gpxe/uri.h>
#include <gpxe/dhcp.h>
#include <gpxe/dhcpopts.h>
/** @file
*
@@ -34,9 +30,6 @@
*
*/
/** List of registered DHCP option blocks */
LIST_HEAD ( dhcp_option_blocks );
/**
* Obtain printable version of a DHCP option tag
*
@@ -58,47 +51,28 @@ static inline char * dhcp_tag_name ( unsigned int tag ) {
}
/**
* Obtain value of a numerical DHCP option
* Get pointer to DHCP option
*
* @v option DHCP option, or NULL
* @ret value Numerical value of the option, or 0
*
* Parses the numerical value from a DHCP option, if present. It is
* permitted to call dhcp_num_option() with @c option set to NULL; in
* this case 0 will be returned.
*
* The caller does not specify the size of the DHCP option data; this
* is implied by the length field stored within the DHCP option
* itself.
* @v options DHCP options block
* @v offset Offset within options block
* @ret option DHCP option
*/
unsigned long dhcp_num_option ( struct dhcp_option *option ) {
unsigned long value = 0;
uint8_t *data;
if ( option ) {
/* This is actually smaller code than using htons()
* etc., and will also cope well with malformed
* options (such as zero-length options).
*/
for ( data = option->data.bytes ;
data < ( option->data.bytes + option->len ) ; data++ )
value = ( ( value << 8 ) | *data );
}
return value;
static inline __attribute__ (( always_inline )) struct dhcp_option *
dhcp_option ( struct dhcp_options *options, unsigned int offset ) {
return ( ( struct dhcp_option * ) ( options->data + offset ) );
}
/**
* Calculate length of a normal DHCP option
* Get offset of a DHCP option
*
* @v options DHCP options block
* @v option DHCP option
* @ret len Length (including tag and length field)
*
* @c option may not be a @c DHCP_PAD or @c DHCP_END option.
* @ret offset Offset within options block
*/
static inline unsigned int dhcp_option_len ( struct dhcp_option *option ) {
assert ( option->tag != DHCP_PAD );
assert ( option->tag != DHCP_END );
return ( option->len + DHCP_OPTION_HEADER_LEN );
static inline __attribute__ (( always_inline )) int
dhcp_option_offset ( struct dhcp_options *options,
struct dhcp_option *option ) {
return ( ( ( void * ) option ) - options->data );
}
/**
@@ -107,11 +81,11 @@ static inline unsigned int dhcp_option_len ( struct dhcp_option *option ) {
* @v option DHCP option
* @ret len Length (including tag and length field)
*/
static inline unsigned int dhcp_any_option_len ( struct dhcp_option *option ) {
static unsigned int dhcp_option_len ( struct dhcp_option *option ) {
if ( ( option->tag == DHCP_END ) || ( option->tag == DHCP_PAD ) ) {
return 1;
} else {
return dhcp_option_len ( option );
return ( option->len + DHCP_OPTION_HEADER_LEN );
}
}
@@ -120,27 +94,27 @@ static inline unsigned int dhcp_any_option_len ( struct dhcp_option *option ) {
*
* @v options DHCP options block
* @v tag DHCP option tag to search for
* @ret encapsulator Encapsulating DHCP option
* @ret option DHCP option, or NULL if not found
* @ret encap_offset Offset of encapsulating DHCP option
* @ret offset Offset of DHCP option, or negative error
*
* Searches for the DHCP option matching the specified tag within the
* DHCP option block. Encapsulated options may be searched for by
* using DHCP_ENCAP_OPT() to construct the tag value.
*
* If the option is encapsulated, and @c encapsulator is non-NULL, it
* will be filled in with a pointer to the encapsulating option.
* will be filled in with the offset of the encapsulating option.
*
* This routine is designed to be paranoid. It does not assume that
* the option data is well-formatted, and so must guard against flaws
* such as options missing a @c DHCP_END terminator, or options whose
* length would take them beyond the end of the data block.
*/
static struct dhcp_option *
find_dhcp_option_with_encap ( struct dhcp_option_block *options,
unsigned int tag,
struct dhcp_option **encapsulator ) {
static int find_dhcp_option_with_encap ( struct dhcp_options *options,
unsigned int tag,
int *encap_offset ) {
unsigned int original_tag __attribute__ (( unused )) = tag;
struct dhcp_option *option = options->data;
struct dhcp_option *option;
int offset = 0;
ssize_t remaining = options->len;
unsigned int option_len;
@@ -149,16 +123,17 @@ find_dhcp_option_with_encap ( struct dhcp_option_block *options,
* if the length is malformed (i.e. takes us beyond
* the end of the data block).
*/
option_len = dhcp_any_option_len ( option );
option = dhcp_option ( options, offset );
option_len = dhcp_option_len ( option );
remaining -= option_len;
if ( remaining < 0 )
break;
/* Check for matching tag */
if ( option->tag == tag ) {
DBG ( "Found DHCP option %s (length %d) in block %p\n",
dhcp_tag_name ( original_tag ), option->len,
options );
return option;
DBGC ( options, "DHCPOPT %p found %s (length %d)\n",
options, dhcp_tag_name ( original_tag ),
option_len );
return offset;
}
/* Check for explicit end marker */
if ( option->tag == DHCP_END )
@@ -166,168 +141,74 @@ find_dhcp_option_with_encap ( struct dhcp_option_block *options,
/* Check for start of matching encapsulation block */
if ( DHCP_IS_ENCAP_OPT ( tag ) &&
( option->tag == DHCP_ENCAPSULATOR ( tag ) ) ) {
if ( encapsulator )
*encapsulator = option;
if ( encap_offset )
*encap_offset = offset;
/* Continue search within encapsulated option block */
tag = DHCP_ENCAPSULATED ( tag );
remaining = option->len;
option = ( void * ) &option->data;
remaining = option_len;
offset += DHCP_OPTION_HEADER_LEN;
continue;
}
option = ( ( ( void * ) option ) + option_len );
offset += option_len;
}
return NULL;
}
/**
* Find DHCP option within DHCP options block
*
* @v options DHCP options block, or NULL
* @v tag DHCP option tag to search for
* @ret option DHCP option, or NULL if not found
*
* Searches for the DHCP option matching the specified tag within the
* DHCP option block. Encapsulated options may be searched for by
* using DHCP_ENCAP_OPT() to construct the tag value.
*
* If @c options is NULL, all registered option blocks will be
* searched. Where multiple option blocks contain the same DHCP
* option, the option from the highest-priority block will be
* returned. (Priority of an options block is determined by the value
* of the @c DHCP_EB_PRIORITY option within the block, if present; the
* default priority is zero).
*/
struct dhcp_option * find_dhcp_option ( struct dhcp_option_block *options,
unsigned int tag ) {
struct dhcp_option *option;
if ( options ) {
return find_dhcp_option_with_encap ( options, tag, NULL );
} else {
list_for_each_entry ( options, &dhcp_option_blocks, list ) {
if ( ( option = find_dhcp_option ( options, tag ) ) )
return option;
}
return NULL;
}
}
/**
* Register DHCP option block
*
* @v options DHCP option block
*
* Register a block of DHCP options.
*/
void register_dhcp_options ( struct dhcp_option_block *options ) {
struct dhcp_option_block *existing;
/* Determine priority of new block */
options->priority = find_dhcp_num_option ( options, DHCP_EB_PRIORITY );
DBG ( "Registering DHCP options block %p with priority %d\n",
options, options->priority );
/* Insert after any existing blocks which have a higher priority */
list_for_each_entry ( existing, &dhcp_option_blocks, list ) {
if ( options->priority > existing->priority )
break;
}
dhcpopt_get ( options );
list_add_tail ( &options->list, &existing->list );
}
/**
* Unregister DHCP option block
*
* @v options DHCP option block
*/
void unregister_dhcp_options ( struct dhcp_option_block *options ) {
list_del ( &options->list );
dhcpopt_put ( options );
}
/**
* Initialise empty block of DHCP options
*
* @v options Uninitialised DHCP option block
* @v data Memory for DHCP option data
* @v max_len Length of memory for DHCP option data
*
* Populates the DHCP option data with a single @c DHCP_END option and
* fills in the fields of the @c dhcp_option_block structure.
*/
void init_dhcp_options ( struct dhcp_option_block *options,
void *data, size_t max_len ) {
struct dhcp_option *option;
options->data = data;
options->max_len = max_len;
option = options->data;
option->tag = DHCP_END;
options->len = 1;
DBG ( "DHCP options block %p initialised (data %p max_len %#zx)\n",
options, options->data, options->max_len );
}
/**
* Allocate space for a block of DHCP options
*
* @v max_len Maximum length of option block
* @ret options DHCP option block, or NULL
*
* Creates a new DHCP option block and populates it with an empty
* options list. This call does not register the options block.
*/
struct dhcp_option_block * alloc_dhcp_options ( size_t max_len ) {
struct dhcp_option_block *options;
options = malloc ( sizeof ( *options ) + max_len );
if ( options ) {
init_dhcp_options ( options,
( (void *) options + sizeof ( *options ) ),
max_len );
}
return options;
return -ENOENT;
}
/**
* Resize a DHCP option
*
* @v options DHCP option block
* @v option DHCP option to resize
* @v encapsulator Encapsulating option (or NULL)
* @v offset Offset of option to resize
* @v encap_offset Offset of encapsulating offset (or -ve for none)
* @v old_len Old length (including header)
* @v new_len New length (including header)
* @v can_realloc Can reallocate options data if necessary
* @ret rc Return status code
*/
static int resize_dhcp_option ( struct dhcp_option_block *options,
struct dhcp_option *option,
struct dhcp_option *encapsulator,
size_t old_len, size_t new_len ) {
void *source = ( ( ( void * ) option ) + old_len );
void *dest = ( ( ( void * ) option ) + new_len );
void *end = ( options->data + options->max_len );
static int resize_dhcp_option ( struct dhcp_options *options,
int offset, int encap_offset,
size_t old_len, size_t new_len,
int can_realloc ) {
struct dhcp_option *encapsulator;
struct dhcp_option *option;
ssize_t delta = ( new_len - old_len );
size_t new_options_len;
size_t new_encapsulator_len;
void *new_data;
void *source;
void *dest;
void *end;
/* Check for sufficient space, and update length fields */
if ( new_len > DHCP_MAX_LEN )
return -ENOMEM;
return -ENOSPC;
new_options_len = ( options->len + delta );
if ( new_options_len > options->max_len )
return -ENOMEM;
if ( encapsulator ) {
if ( new_options_len > options->max_len ) {
/* Reallocate options block if allowed to do so. */
if ( can_realloc ) {
new_data = realloc ( options->data, new_options_len );
if ( ! new_data )
return -ENOMEM;
options->data = new_data;
options->max_len = new_options_len;
} else {
return -ENOMEM;
}
}
if ( encap_offset >= 0 ) {
encapsulator = dhcp_option ( options, encap_offset );
new_encapsulator_len = ( encapsulator->len + delta );
if ( new_encapsulator_len > DHCP_MAX_LEN )
return -ENOMEM;
return -ENOSPC;
encapsulator->len = new_encapsulator_len;
}
options->len = new_options_len;
/* Move remainder of option data */
option = dhcp_option ( options, offset );
source = ( ( ( void * ) option ) + old_len );
dest = ( ( ( void * ) option ) + new_len );
end = ( options->data + options->max_len );
memmove ( dest, source, ( end - dest ) );
return 0;
@@ -340,7 +221,8 @@ static int resize_dhcp_option ( struct dhcp_option_block *options,
* @v tag DHCP option tag
* @v data New value for DHCP option
* @v len Length of value, in bytes
* @ret option DHCP option, or NULL
* @v can_realloc Can reallocate options data if necessary
* @ret offset Offset of DHCP option, or negative error
*
* Sets the value of a DHCP option within the options block. The
* option may or may not already exist. Encapsulators will be created
@@ -350,97 +232,183 @@ static int resize_dhcp_option ( struct dhcp_option_block *options,
* If it does fail, and the option existed previously, the option will
* be left with its original value.
*/
struct dhcp_option * set_dhcp_option ( struct dhcp_option_block *options,
unsigned int tag,
const void *data, size_t len ) {
static int set_dhcp_option ( struct dhcp_options *options, unsigned int tag,
const void *data, size_t len,
int can_realloc ) {
static const uint8_t empty_encapsulator[] = { DHCP_END };
int offset;
int encap_offset = -1;
int creation_offset = 0;
struct dhcp_option *option;
void *insertion_point;
struct dhcp_option *encapsulator = NULL;
unsigned int encap_tag = DHCP_ENCAPSULATOR ( tag );
size_t old_len = 0;
size_t new_len = ( len ? ( len + DHCP_OPTION_HEADER_LEN ) : 0 );
/* Return NULL if no options block specified */
if ( ! options )
return NULL;
int rc;
/* Find old instance of this option, if any */
option = find_dhcp_option_with_encap ( options, tag, &encapsulator );
if ( option ) {
old_len = dhcp_option_len ( option );
DBG ( "Resizing DHCP option %s from length %d to %zd in block "
"%p\n", dhcp_tag_name (tag), option->len, len, options );
offset = find_dhcp_option_with_encap ( options, tag, &encap_offset );
if ( offset >= 0 ) {
old_len = dhcp_option_len ( dhcp_option ( options, offset ) );
DBGC ( options, "DHCPOPT %p resizing %s from %zd to %zd\n",
options, dhcp_tag_name ( tag ), old_len, new_len );
} else {
old_len = 0;
DBG ( "Creating DHCP option %s (length %zd) in block %p\n",
dhcp_tag_name ( tag ), len, options );
DBGC ( options, "DHCPOPT %p creating %s (length %zd)\n",
options, dhcp_tag_name ( tag ), len );
}
/* Ensure that encapsulator exists, if required */
insertion_point = options->data;
if ( DHCP_IS_ENCAP_OPT ( tag ) ) {
if ( ! encapsulator )
encapsulator = set_dhcp_option ( options, encap_tag,
empty_encapsulator,
sizeof ( empty_encapsulator) );
if ( ! encapsulator )
return NULL;
insertion_point = &encapsulator->data;
if ( encap_tag ) {
if ( encap_offset < 0 )
encap_offset = set_dhcp_option ( options, encap_tag,
empty_encapsulator, 1,
can_realloc );
if ( encap_offset < 0 )
return encap_offset;
creation_offset = ( encap_offset + DHCP_OPTION_HEADER_LEN );
}
/* Create new option if necessary */
if ( ! option )
option = insertion_point;
if ( offset < 0 )
offset = creation_offset;
/* Resize option to fit new data */
if ( resize_dhcp_option ( options, option, encapsulator,
old_len, new_len ) != 0 )
return NULL;
if ( ( rc = resize_dhcp_option ( options, offset, encap_offset,
old_len, new_len,
can_realloc ) ) != 0 )
return rc;
/* Copy new data into option, if applicable */
if ( len ) {
option = dhcp_option ( options, offset );
option->tag = tag;
option->len = len;
memcpy ( &option->data, data, len );
}
/* Delete encapsulator if there's nothing else left in it */
if ( encapsulator && ( encapsulator->len <= 1 ) )
set_dhcp_option ( options, encap_tag, NULL, 0 );
if ( encap_offset >= 0 ) {
option = dhcp_option ( options, encap_offset );
if ( option->len <= 1 )
set_dhcp_option ( options, encap_tag, NULL, 0, 0 );
}
return option;
return offset;
}
/**
* Find DHCP numerical option, and return its value
* Store value of DHCP option setting
*
* @v options DHCP options block
* @v tag DHCP option tag to search for
* @ret value Numerical value of the option, or 0 if not found
*
* This function exists merely as a notational shorthand for a call to
* find_dhcp_option() followed by a call to dhcp_num_option(). It is
* not possible to distinguish between the cases "option not found"
* and "option has a value of zero" using this function; if this
* matters to you then issue the two constituent calls directly and
* check that find_dhcp_option() returns a non-NULL value.
* @v options DHCP option block
* @v tag Setting tag number
* @v data Setting data, or NULL to clear setting
* @v len Length of setting data
* @ret rc Return status code
*/
unsigned long find_dhcp_num_option ( struct dhcp_option_block *options,
unsigned int tag ) {
return dhcp_num_option ( find_dhcp_option ( options, tag ) );
int dhcpopt_store ( struct dhcp_options *options, unsigned int tag,
const void *data, size_t len ) {
int offset;
offset = set_dhcp_option ( options, tag, data, len, 0 );
if ( offset < 0 )
return offset;
return 0;
}
/**
* Delete DHCP option
* Store value of DHCP option setting, extending options block if necessary
*
* @v options DHCP options block
* @v tag DHCP option tag
*
* This function exists merely as a notational shorthand for a call to
* set_dhcp_option() with @c len set to zero.
* @v options DHCP option block
* @v tag Setting tag number
* @v data Setting data, or NULL to clear setting
* @v len Length of setting data
* @ret rc Return status code
*/
void delete_dhcp_option ( struct dhcp_option_block *options,
unsigned int tag ) {
set_dhcp_option ( options, tag, NULL, 0 );
int dhcpopt_extensible_store ( struct dhcp_options *options, unsigned int tag,
const void *data, size_t len ) {
int offset;
offset = set_dhcp_option ( options, tag, data, len, 1 );
if ( offset < 0 )
return offset;
return 0;
}
/**
* Fetch value of DHCP option setting
*
* @v options DHCP option block
* @v tag Setting tag number
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*/
int dhcpopt_fetch ( struct dhcp_options *options, unsigned int tag,
void *data, size_t len ) {
int offset;
struct dhcp_option *option;
size_t option_len;
offset = find_dhcp_option_with_encap ( options, tag, NULL );
if ( offset < 0 )
return offset;
option = dhcp_option ( options, offset );
option_len = dhcp_option_len ( option );
if ( len > option_len )
len = option_len;
memcpy ( data, option->data, len );
return option_len;
}
/**
* Recalculate length of DHCP options block
*
* @v options Uninitialised DHCP option block
*
* The "used length" field will be updated based on scanning through
* the block to find the end of the options.
*/
static void dhcpopt_update_len ( struct dhcp_options *options ) {
struct dhcp_option *option;
int offset = 0;
ssize_t remaining = options->max_len;
unsigned int option_len;
/* Find last non-pad option */
options->len = 0;
while ( remaining ) {
option = dhcp_option ( options, offset );
option_len = dhcp_option_len ( option );
remaining -= option_len;
if ( remaining < 0 )
break;
offset += option_len;
if ( option->tag != DHCP_PAD )
options->len = offset;
}
}
/**
* Initialise prepopulated block of DHCP options
*
* @v options Uninitialised DHCP option block
* @v data Memory for DHCP option data
* @v max_len Length of memory for DHCP option data
*
* The memory content must already be filled with valid DHCP options.
* A zeroed block counts as a block of valid DHCP options.
*/
void dhcpopt_init ( struct dhcp_options *options, void *data,
size_t max_len ) {
/* Fill in fields */
options->data = data;
options->max_len = max_len;
/* Update length */
dhcpopt_update_len ( options );
DBGC ( options, "DHCPOPT %p created (data %p len %#zx max_len %#zx)\n",
options, options->data, options->len, options->max_len );
}