81 lines
1.5 KiB
C
81 lines
1.5 KiB
C
#ifndef _PKBUFF_H
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#define _PKBUFF_H
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/** @file
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*
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* Packet buffers
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*
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* Packet buffers are used to contain network packets. Methods are
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* provided for appending, prepending, etc. data.
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*
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*/
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#include <stdint.h>
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#include <assert.h>
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/** A packet buffer
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*
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* This structure is used to represent a network packet within gPXE.
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*/
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struct pk_buff {
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/** Head of the buffer */
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void *head;
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/** Start of data */
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void *data;
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/** End of data */
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void *tail;
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/** End of the buffer */
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void *end;
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};
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/**
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* Add data to start of packet buffer
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*
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* @v pkb Packet buffer
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* @v len Length to add
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* @ret data Pointer to new start of buffer
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*/
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static inline void * pkb_push ( struct pk_buff *pkb, size_t len ) {
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pkb->data -= len;
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assert ( pkb->data >= pkb->head );
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return pkb->data;
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}
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/**
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* Remove data from start of packet buffer
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*
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* @v pkb Packet buffer
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* @v len Length to remove
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* @ret data Pointer to new start of buffer
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*/
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static inline void * pkb_pull ( struct pk_buff *pkb, size_t len ) {
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pkb->data += len;
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assert ( pkb->data >= pkb->tail );
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return pkb->data;
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}
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/**
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* Add data to end of packet buffer
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*
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* @v pkb Packet buffer
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* @v len Length to add
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* @ret data Pointer to newly added space
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*/
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static inline void * pkb_put ( struct pk_buff *pkb, size_t len ) {
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void *old_tail = pkb->tail;
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pkb->tail += len;
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assert ( pkb->tail <= pkb->end );
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return old_tail;
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}
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/**
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* Empty a packet buffer
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*
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* @v pkb Packet buffer
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*/
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static inline void pkb_empty ( struct pk_buff *pkb ) {
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pkb->tail = pkb->data;
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}
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#endif /* _PKBUFF_H */
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