135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
/*************************************************************************
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> File Name : icmp_proxy.c
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> Author : TL Song
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> EMail : songtianlun@frytea.com
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> Created Time : Thu Feb 18 19:23:50 2021
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************************************************************************/
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#include <stdio.h>
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#include <string.h>
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#include <pcap.h>
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#define SNAP_LEN 65536
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static char g_ftag[6] = {0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE};
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/*
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struct pcap_pkthdr
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{
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struct timeval ts; ts是一个结构struct timeval，它有两个部分，第一部分是1900开始以来的秒数，第二部分是当前秒之后的毫秒数
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bpf_u_int32 caplen; 表示抓到的数据长度
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bpf_u_int32 len; 表示数据包的实际长度
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}
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*/
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#define dPrint(fmt, ...) do{fprintf(stderr, "[%s:%d] " fmt "\r\n", __FUNCTION__, __LINE__, ##__VA_ARGS__);}while(0)
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#define HexPrint(_buf, _len) \
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{\
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int _m_i = 0;\
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char *_m_buf = (char *)(_buf);\
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int _m_len = (int)(_len);\
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printf("[%s:%d] \r\n", __FUNCTION__, __LINE__);\
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printf("*****************************\n");\
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for(_m_i = 0; _m_i < _m_len; _m_i++)\
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{\
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printf("\033[32m%02x \033[0m", _m_buf[_m_i] & 0xff);\
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if(!((_m_i+1) % 10)) printf("\n");\
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}\
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printf("\nsize = %d\n*****************************\n", _m_len);\
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}
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int send_pkt_pcap(const u_char *pkt, int len)
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{
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static pcap_t *handle = NULL;
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char dev_str[64];
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char err_buf[PCAP_ERRBUF_SIZE];
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strcpy(dev_str, "eth1");
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if(NULL == handle)
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{
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handle = pcap_open_live(dev_str, SNAP_LEN, 1, 1000, err_buf);
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if (handle == NULL)
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{
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fprintf(stderr, "Couldn't open device %s: %s\n", dev_str, err_buf);
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return 0;
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}
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}
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return pcap_sendpacket(handle, pkt, len);
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}
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void dispatcher_handler(u_char *temp1, const struct pcap_pkthdr *header, const u_char *pkt_data)
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{
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HexPrint((const char *)pkt_data, header->caplen);
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u_char pkt_send[header->caplen + sizeof(g_ftag)];
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memset(pkt_send, 0x00, sizeof(pkt_send));
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memcpy(pkt_send, g_ftag, sizeof(g_ftag));
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memcpy(pkt_send + sizeof(g_ftag), pkt_data, header->caplen);
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HexPrint((const char *)pkt_send, sizeof(pkt_send));
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dPrint("Send ret : %d", send_pkt_pcap((const u_char *)pkt_send, sizeof(pkt_send)));
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}
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int main()
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{
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pcap_t *handle;
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char err_buf[PCAP_ERRBUF_SIZE];
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char dev_str[64];
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struct bpf_program fp;
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strcpy(dev_str, "eth0");
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/* open capture device */
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handle = pcap_open_live(dev_str, SNAP_LEN, 1, 1000, err_buf);
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if (handle == NULL)
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{
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fprintf(stderr, "Couldn't open device %s: %s\n", dev_str, err_buf);
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return 0;
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}
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/* make sure we're capturing on an Ethernet device*/
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if (pcap_datalink(handle) != DLT_EN10MB)
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{
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fprintf(stderr, "%s is not an Ethernet\n", dev_str);
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return 0;
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}
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/* compile the filter expression */
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if (pcap_compile(handle, &fp, "vlan and src host 192.168.1.123", 0, 24) == -1)
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{
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fprintf(stderr, "Couldn't parse filter %s: %s\n",
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"***", pcap_geterr(handle));
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return 0;
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}
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/* apply the compiled filter */
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if (pcap_setfilter(handle, &fp) == -1)
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{
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fprintf(stderr, "Couldn't install filter %s: %s\n",
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"***", pcap_geterr(handle));
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return 0;
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}
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pcap_loop(handle, -1, dispatcher_handler, NULL);
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/* cleanup */
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pcap_freecode(&fp);
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pcap_close(handle);
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dPrint("Capture complete.");
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return 0;
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} |