packet_datalink.c

Java抓包必备

#include<jni.h>
#include<pcap.h>

#include<net/bpf.h>

#ifndef WIN32
#include<sys/param.h>
#define __FAVOR_BSD
#include<netinet/in.h>
#else
#include<winsock.h>
#endif

#include<netinet/in_systm.h>

#include"Jpcap_sub.h"
#include"Jpcap_ether.h"

/** analyze datalink layer (ethernet) **/
jobject analyze_datalink(u_char *data){
  struct ether_header *ether_hdr;
  jobject packet;
  jbyteArray src_addr,dst_addr;

#ifdef DEBUG
  puts("analyze datalink");
#endif

  switch(linktype){
  case DLT_EN10MB:
    packet=AllocObject(EthernetPacket);
    src_addr=(*jni_env)->NewByteArray(jni_env,6);
    dst_addr=(*jni_env)->NewByteArray(jni_env,6);
    ether_hdr=(struct ether_header *)data;
    (*jni_env)->SetByteArrayRegion(jni_env,src_addr,0,6,ether_hdr->ether_src);
    (*jni_env)->SetByteArrayRegion(jni_env,dst_addr,0,6,ether_hdr->ether_dest);
    (*jni_env)->CallVoidMethod(jni_env,packet,setEthernetValueMID,dst_addr,src_addr,
		(jchar)ntohs(ether_hdr->ether_type));
    DeleteLocalRef(src_addr);
    DeleteLocalRef(dst_addr);
    break;
  default:
    packet=AllocObject(DatalinkPacket);
    break;
  }

  return packet;
}

void set_ether(JNIEnv *env,jobject packet,char *pointer){
	struct ether_header *ether_hdr=(struct ether_header *)pointer;

	jbyteArray src=GetObjectField(EthernetPacket,packet,"src_mac","[B");
	jbyteArray dst=GetObjectField(EthernetPacket,packet,"dst_mac","[B");

	(*env)->GetByteArrayRegion(env,src,0,6,(char *)&ether_hdr->ether_src);
	(*env)->GetByteArrayRegion(env,dst,0,6,(char *)&ether_hdr->ether_dest);
	ether_hdr->ether_type=htons(GetShortField(EthernetPacket,packet,"frametype"));
}