packet.h

一个学习SNMP项目：tmoerlan.

/* $Id: packet.h,v 1.2 2003/09/17 11:26:10 tmoerlan Exp $ */


#ifndef _SNAP_PACKET_H_
#define _SNAP_PACKET_H_

#ifdef __KERNEL__
#include <linux/skbuff.h>
#include <snap/bytecode.h>
#else
#include "bytecode.h"
#endif


/* a heap is just a buffer with some meta-data off the front */
typedef struct {
  int lenb;			/* for now, length in bytes */
  char *h;			/* the heap */
} heap_t;

/* packet header layout */
#include "snap.h"
typedef struct snaphdr header_t;

/* active packets */
typedef struct {
  header_t *hdr;
  unsigned char rb;
  /* code */
  instr_t *code_min;
  instr_t *pc;
  instr_t *handler;
  instr_t *code_max;
  /* stack */
  value_t *stack_min;
  value_t *sp; 		  /* points above top value (i.e. alloc, then incr) */
  value_t *stack_max;
  /* in-packet heap */
  void *heap_min;
  void *h_alloc_ptr; 	  /* used only during assembly */
  void *heap_max;
  /* heap allocation pointer at runtime is stack_max, growing down;
     value pointed to by stack_max is legal (i.e. decr, then alloc) */
  void *h_alloc_heap_max; /* essentially the top of the buffer */
  /* used for optimizing marshalling---allows the marshaller to
     assume that the packet is already marshalled, starting at the
     hdr address. */
  unsigned int is_contiguous;
  int resized;			/* whether we have resized the buffer
				   or not */
#ifdef __KERNEL__
  struct sk_buff *skb;
#else
  struct iphdr *iph;		/* points to the IP header of the
				   buffer the packet is stored in */
#endif /* __KERNEL__ */
} packet_t;

#ifndef __KERNEL__
extern void fprintf_packet(FILE *f,packet_t *p);
#endif /* !__KERNEL__ */

#endif /* _SNAP_PACKET_H_ */