encodedheader.hh

来自「COPE the first practical network coding 」· HH 代码 · 共 62 行

/* Header for the encoded packet */

#ifndef CLICK_XORED_HH
#define CLICK_XORED_HH

#include <clicknet/ip.h>

// packet format
CLICK_SIZE_PACKED_STRUCTURE(
struct click_xored {,


  uint16_t    ether_type[2];  // the original ethertype of both packets
  uint16_t    seq[2];         // IP seq numbers for both
  uint32_t    prev_hop[2];    // the previous hop for either packets 
  uint32_t    src[2];         // the source IP address of both packets
  // note that the values in these arrays should be associative
  // i.e., info for the same 'source' should use the same index

  uint16_t    short_length;   // the length of the shorter packet

  uint16_t    _cksum;
  uint16_t    _dlen;

  // all methods below adapted from srpacket.hh
  void set_data_len(uint16_t len) {
    _dlen = htons(len);
  }

  size_t data_len() {
    return ntohs(_dlen);
  }

  // *** is this right?
  size_t hlen_wo_data() {
    return sizeof(struct click_xored);
  }

  size_t hlen_with_data() const { return len_with_data(ntohs(_dlen)); }
  static size_t len_with_data(int dlen) {
    return sizeof(struct click_xored) + dlen;
  }


  void set_checksum() {
    // all packets should carry data, so let's not worry about empty payloads
    unsigned int tlen = hlen_with_data();
    /*
    if (_type & PT_DATA) {
      tlen = hlen_with_data();
    } else {
      tlen = hlen_wo_data();
    }
    */
    _cksum = 0;
    _cksum = click_in_cksum((unsigned char *) this, tlen);
  }

});

#endif