packet_datalink.c

JAVA 抓包系统~~~提取数据包分析。分离出TCP UDP ARP 等包

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

#ifndef WIN32
#include<sys/param.h>
#define __FAVOR_BSD
#include<netinet/in.h>
//#include<net/bpf.h>
#include<pcap-bpf.h>
#else
#include<winsock2.h>
#endif

#include<netinet/in_systm.h>

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

/** analyze datalink layer (ethernet) **/
jobject analyze_datalink(JNIEnv *env,u_char *data,int linktype){
  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=(*env)->NewByteArray(env,6);
    dst_addr=(*env)->NewByteArray(env,6);
    ether_hdr=(struct ether_header *)data;
    (*env)->SetByteArrayRegion(env,src_addr,0,6,ether_hdr->ether_src);
    (*env)->SetByteArrayRegion(env,dst_addr,0,6,ether_hdr->ether_dest);
    (*env)->CallVoidMethod(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;
}

int set_ether(JNIEnv *env,jobject packet,char *pointer){
	packet=GetObjectField(Packet,packet,"Ljpcap/packet/DatalinkPacket;","datalink");
	if(packet!=NULL && IsInstanceOf(packet,EthernetPacket)){
		struct ether_header *ether_hdr=(struct ether_header *)pointer;

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

		(*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"));

  (*env)->ExceptionDescribe(env);
		return sizeof(struct ether_header);
	}
	return 0;
}