libpcap--GTPv2协议的cap文件解析

最新推荐文章于 2022-07-13 16:43:58 发布

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#libpcap #GTPv2 #cap

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本文介绍了一段C++代码，该代码用于解析GTPv2（GPRS隧道协议版本2）的消息包，并打印出包括源MAC地址、目的MAC地址、IP地址、端口等在内的关键信息。此外，还详细展示了如何根据不同的消息类型来判断GTPv2的具体操作，如创建会话请求、修改承载请求等。

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#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

using std::cout;
using std::endl;
using std::thread;
using std::vector;
using std::string;


void getPacket(u_char * arg,const struct pcap_pkthdr *pkthdr,const u_char * packet);


int main(int argc,char * argv [ ])
{
	if (argc < 2){
		cout << "please input test filename\n";
		return 0;
	}

	cout << "test filename= " << argv[1] << endl;
	cout << "begin time= " << time(0) << endl;

	//读取libpcap的版本
	const char *version;
	version = pcap_lib_version();
	cout << version << endl;

	//打开cap文件
	char *dev = NULL;
	char errBuff[PCAP_ERRBUF_SIZE] = {0};
	pcap_t *handle = NULL;

	handle = pcap_open_offline(argv[1], errBuff);
	if (NULL == handle){
		cout << "Error: " << errBuff << endl;
		exit(1);
	}

	cout << "running pcap_next\n";

	//读取cap文件，打印抓取到的每一个包的概要
	struct pcap_pkthdr *pktHeader = NULL;
	int status = 0;
	const u_char *pktData = NULL;
	int id = 0;

	do{		
		cout << "---------------------------------------------------------------------\n";
		cout << "status: " << status << endl;
		status = pcap_next_ex(handle, &pktHeader, &pktData);		
		getPacket((u_char *)&id, pktHeader, pktData);
	}while(status == 1);

	pcap_close(handle);
	cout << "end time=" << time(0) << endl;
	return 0;
}


//解析数据包
void getPacket(u_char * arg,const struct pcap_pkthdr *pkthdr,const u_char * packet){
	char src_mac[18] = "";
	char dst_mac[18] = "";
	char src_addr[20] = "";	
	char dst_addr[20] = "";
	
	vector split_vector;
	char *p = NULL;
	const char *split = "|";

	int *id = (int *)arg;
	cout << "id: " << ++(*id) << endl;
	cout << "Packet length: " << pkthdr->len << endl;
	cout << "Number of bytes: " << pkthdr->caplen << endl;
	cout << "Recieved time: " << ctime((const time_t *)&pkthdr->ts.tv_sec);

	if (pkthdr->len < 42)
	{
		cout << "wifi TanZhen message length error." << endl;
		exit(1);
	}
	

	sprintf(dst_mac, "%02x:%02x:%02x:%02x:%02x:%02x", *(packet + 0), *(packet + 1), *(packet + 2), *(packet + 3), *(packet + 4), *(packet + 5));	
	sprintf(src_mac, "%02x:%02x:%02x:%02x:%02x:%02x", *(packet + 6), *(packet + 7), *(packet + 8), *(packet + 9), *(packet + 10), *(packet + 11));	

	//消息头
	if (*(packet + 12) == 0x08 && *(packet + 13) == 0x00)
	{
		printf("____________________IP Protocol____________________\n");
		printf("MAC:%s >> %s\n", src_mac, dst_mac);
		sprintf(src_addr, "%02d.%02d.%02d.%02d", *(packet + 26), *(packet + 27), *(packet + 28), *(packet + 29));	
		sprintf(dst_addr, "%02d.%02d.%02d.%02d", *(packet + 30), *(packet + 31), *(packet + 32), *(packet + 33));
		printf("IP:%s >> %s\n", src_addr, dst_addr);

		if (*(packet + 23) == 0x01)
		{
			printf("____________________ICMP____________________\n");
		}
		else if (*(packet + 23) == 0x02)
		{
			printf("____________________IGMP____________________\n");
		}
		else if (*(packet + 23) == 0x06)
		{
			printf("____________________TCP____________________\n");
		}		
		else if (*(packet + 23) == 0x11)
		{
			printf("____________________UDP____________________\n");
		}

		printf("Port: %d >> %d\n", ntohs(*(unsigned short *)(packet + 34)), ntohs(*(unsigned short *)(packet + 36)));
	}

	//GTPv2消息解析
	printf("________________GPRS Tunneling Protocol________________\n");
	printf("Flag:%02x\n", *(packet + 42));
	if (*(packet + 43) == 0x01){
		printf("type: Echo Request\n");
	}
	else if (*(packet + 43) == 0x02){
		printf("type: Echo Response\n");
	}
	else if (*(packet + 43) == 0x10){
		printf("type: Create PDP context request\n");
	}
	else if (*(packet + 43) == 0x11){
		printf("type: Create PDP context response\n");
	}
	else if (*(packet + 43) == 0x12){
		printf("type: Update PDP context request\n");
	}
	else if (*(packet + 43) == 0x13){
		printf("type: Update PDP context Response\n");
	}
	else if (*(packet + 43) == 0x14){
		printf("type: Delete PDP context request\n");
	}
	else if (*(packet + 43) == 0x15){
		printf("type: Delete PDP context Response\n");
	}
	else if (*(packet + 43) == 0x20){
		printf("type: Create Session Request\n");
	}
	else if (*(packet + 43) == 0x21){
		printf("type: Create Session Response\n");
	}
	else if (*(packet + 43) == 0x22){
		printf("type: Modify Bearer Request\n");
	}
	else if (*(packet + 43) == 0x23){
		printf("type: Modify Bearer Response\n");
	}
	else if (*(packet + 43) == 0x24){
		printf("type: Delete Session Request\n");
	}
	else if (*(packet + 43) == 0x25){
		printf("type: Delete Session Response\n");
	}
	else if (*(packet + 43) == 0x30){
		printf("type: Identification request\n");
	}
	else if (*(packet + 43) == 0x31){
		printf("type: Identification Response\n");
	}
	else if (*(packet + 43) == 0x32){
		printf("type: SGSN context request\n");
	}
	else if (*(packet + 43) == 0x33){
		printf("type: SGSN context reponse\n");
	}
	else if (*(packet + 43) == 0x34){
		printf("type: SGSN context acknowledegment\n");
	}
	else if (*(packet + 43) == 0x40){
		printf("type: Modify Bearer Command\n");
	}
	else if (*(packet + 43) == 0x46){
		printf("type: Downlink Data Notification Failure Indication\n");
	}
	else if (*(packet + 43) == 0x61){
		printf("type: Update Bearer Request\n");
	}
	else if (*(packet + 43) == 0x62){
		printf("type: Update Bearer Response\n");
	}
	else if (*(packet + 43) == 0x63){
		printf("type: Delete Bearer Request\n");
	}
	else if (*(packet + 43) == 0x64){
		printf("type: Delete Bearer Response\n");
	}
	else if (*(packet + 43) == 0x82){
		printf("type: Context Request, Tracking area update request\n");
	}
	else if (*(packet + 43) == 0x83){
		printf("type: Context Response\n");
	}
	else if (*(packet + 43) == 0x84){
		printf("type: Context Acknowledge\n");
	}
	else if (*(packet + 43) == 0x85){
		printf("type: Forward Relocation Request\n");
	}
	else if (*(packet + 43) == 0x8d){
		printf("type: Configuration Transfer Tunnel\n");
	}
	else if (*(packet + 43) == 0xa6){
		printf("type: Create Indirect Data Forwarding Tunnel Request\n");
	}
	else if (*(packet + 43) == 0xa7){
		printf("type: Create Indirect Data Forwarding Tunnel Response\n");
	}
	else if (*(packet + 43) == 0xa8){
		printf("type: Delete Indirect Data Forwarding Tunnel Request\n");
	}
	else if (*(packet + 43) == 0xa9){
		printf("type: Delete Indirect Data Forwarding Tunnel Response\n");
	}
	else if (*(packet + 43) == 0xaa){
		printf("type: Release Access Bearers Request\n");
	}
	else if (*(packet + 43) == 0xab){
		printf("type: Release Access Bearers Response\n");
	}
	else if (*(packet + 43) == 0xb0){
		printf("type: Downlink Data Notification\n");
	}
	else if (*(packet + 43) == 0xb1){
		printf("type: Downlink Data Notification Acknowledgement\n");
	}

	
	printf("Length: %d\n", ntohs(*(unsigned short *)(packet + 44)));
	printf("TEID:0x%02x%02x%02x%02x\n", *(packet + 46), *(packet + 47), *(packet + 48), *(packet + 49));	
	printf("Sequence Number:0x00%02x%02x%02x\n", *(packet + 50), *(packet + 51), *(packet + 52));
}