#ifndef _IPXE_IOBUF_H
#define _IPXE_IOBUF_H
/** @file
*
* I/O buffers
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <assert.h>
#include <ipxe/list.h>
/**
* Minimum I/O buffer length
*
* alloc_iob() will round up the allocated length to this size if
* necessary. This is used on behalf of hardware that is not capable
* of auto-padding.
*/
#define IOB_ZLEN 128
/**
* A persistent I/O buffer
*
* This data structure encapsulates a long-lived I/O buffer. The
* buffer may be passed between multiple owners, queued for possible
* retransmission, etc.
*/
struct io_buffer {
/** List of which this buffer is a member
*
* The list must belong to the current owner of the buffer.
* Different owners may maintain different lists (e.g. a
* retransmission list for TCP).
*/
struct list_head list;
/** Start of the buffer */
void *head;
/** Start of data */
void *data;
/** End of data */
void *tail;
/** End of the buffer */
void *end;
};
/**
* Reserve space at start of I/O buffer
*
* @v iobuf I/O buffer
* @v len Length to reserve
* @ret data Pointer to new start of buffer
*/
static inline void * iob_reserve ( struct io_buffer *iobuf, size_t len ) {
iobuf->data += len;
iobuf->tail += len;
return iobuf->data;
}
#define iob_reserve( iobuf, len ) ( { \
void *__result; \
__result = iob_reserve ( (iobuf), (len) ); \
assert ( (iobuf)->tail <= (iobuf)->end ); \
__result; } )
/**
* Add data to start of I/O buffer
*
* @v iobuf I/O buffer
* @v len Length to add
* @ret data Pointer to new start of buffer
*/
static inline void * iob_push ( struct io_buffer *iobuf, size_t len ) {
iobuf->data -= len;
return iobuf->data;
}
#define iob_push( iobuf, len ) ( { \
void *__result; \
__result = iob_push ( (iobuf), (len) ); \
assert ( (iobuf)->data >= (iobuf)->head ); \
__result; } )
/**
* Remove data from start of I/O buffer
*
* @v iobuf I/O buffer
* @v len Length to remove
* @ret data Pointer to new start of buffer
*/
static inline void * iob_pull ( struct io_buffer *iobuf, size_t len ) {
iobuf->data += len;
assert ( iobuf->data <= iobuf->tail );
return iobuf->data;
}
#define iob_pull( iobuf, len ) ( { \
void *__result; \
__result = iob_pull ( (iobuf), (len) ); \
assert ( (iobuf)->data <= (iobuf)->tail ); \
__result; } )
/**
* Add data to end of I/O buffer
*
* @v iobuf I/O buffer
* @v len Length to add
* @ret data Pointer to newly added space
*/
static inline void * iob_put ( struct io_buffer *iobuf, size_t len ) {
void *old_tail = iobuf->tail;
iobuf->tail += len;
return old_tail;
}
#define iob_put( iobuf, len ) ( { \
void *__result; \
__result = iob_put ( (iobuf), (len) ); \
assert ( (iobuf)->tail <= (iobuf)->end ); \
__result; } )
/**
* Remove data from end of I/O buffer
*
* @v iobuf I/O buffer
* @v len Length to remove
*/
static inline void iob_unput ( struct io_buffer *iobuf, size_t len ) {
iobuf->tail -= len;
}
#define iob_unput( iobuf, len ) do { \
iob_unput ( (iobuf), (len) ); \
assert ( (iobuf)->tail >= (iobuf)->data ); \
} while ( 0 )
/**
* Empty an I/O buffer
*
* @v iobuf I/O buffer
*/
static inline void iob_empty ( struct io_buffer *iobuf ) {
iobuf->tail = iobuf->data;
}
/**
* Calculate length of data in an I/O buffer
*
* @v iobuf I/O buffer
* @ret len Length of data in buffer
*/
static inline size_t iob_len ( struct io_buffer *iobuf ) {
return ( iobuf->tail - iobuf->data );
}
/**
* Calculate available space at start of an I/O buffer
*
* @v iobuf I/O buffer
* @ret len Length of data available at start of buffer
*/
static inline size_t iob_headroom ( struct io_buffer *iobuf ) {
return ( iobuf->data - iobuf->head );
}
/**
* Calculate available space at end of an I/O buffer
*
* @v iobuf I/O buffer
* @ret len Length of data available at end of buffer
*/
static inline size_t iob_tailroom ( struct io_buffer *iobuf ) {
return ( iobuf->end - iobuf->tail );
}
/**
* Create a temporary I/O buffer
*
* @v iobuf I/O buffer
* @v data Data buffer
* @v len Length of data
* @v max_len Length of buffer
*
* It is sometimes useful to use the iob_xxx() methods on temporary
* data buffers.
*/
static inline void iob_populate ( struct io_buffer *iobuf,
void *data, size_t len, size_t max_len ) {
iobuf->head = iobuf->data = data;
iobuf->tail = ( data + len );
iobuf->end = ( data + max_len );
}
/**
* Disown an I/O buffer
*
* @v iobuf I/O buffer
*
* There are many functions that take ownership of the I/O buffer they
* are passed as a parameter. The caller should not retain a pointer
* to the I/O buffer. Use iob_disown() to automatically nullify the
* caller's pointer, e.g.:
*
* xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );
*
* This will ensure that iobuf is set to NULL for any code after the
* call to xfer_deliver_iob().
*/
#define iob_disown( iobuf ) ( { \
struct io_buffer *__iobuf = (iobuf); \
(iobuf) = NULL; \
__iobuf; } )
extern struct io_buffer * __malloc alloc_iob_raw ( size_t len, size_t align,
size_t offset );
extern struct io_buffer * __malloc alloc_iob ( size_t len );
extern void free_iob ( struct io_buffer *iobuf );
extern void iob_pad ( struct io_buffer *iobuf, size_t min_len );
extern int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len );
extern struct io_buffer * iob_concatenate ( struct list_head *list );
extern struct io_buffer * iob_split ( struct io_buffer *iobuf, size_t len );
#endif /* _IPXE_IOBUF_H */
