299 lines
8.9 KiB
C
299 lines
8.9 KiB
C
#include <memory.h>
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#include <string.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <net/if.h>
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#include "pcap_device.h"
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#define PCAP_MAC_ADDR_LEN 6
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static int mac_is_zero(const uint8_t* mac_addr) {
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if (mac_addr == NULL) {
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return 1;
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}
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for (int i = 0; i < PCAP_MAC_ADDR_LEN; i++) {
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if (mac_addr[i]) {
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return 0;
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}
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}
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return 1;
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}
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static int read_interface_mac(const char* if_name, uint8_t* mac_addr) {
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if ((if_name == NULL) || (mac_addr == NULL)) {
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return -1;
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}
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int fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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return -1;
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}
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struct ifreq ifr;
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memset(&ifr, 0, sizeof(ifr));
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strncpy(ifr.ifr_name, if_name, IFNAMSIZ - 1);
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if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
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close(fd);
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return -1;
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}
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memcpy(mac_addr, (uint8_t*)ifr.ifr_hwaddr.sa_data, PCAP_MAC_ADDR_LEN);
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close(fd);
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return 0;
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}
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static int load_pcap_lib() {
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return 0;
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}
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/**
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* 找到指定IP地址的网卡名
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* @param ip 物理网卡或者由虚拟软件生成的虚拟刚卡, 字符串形式，如"192.168.1.1"
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* @param name_buf 找到的对应网卡名称
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*/
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static int pcap_find_device(const char* ip, char* name_buf) {
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char err_buf[PCAP_ERRBUF_SIZE];
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pcap_if_t* pcap_if_list = NULL;
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struct in_addr dest_ip;
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pcap_if_t* item;
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inet_pton(AF_INET, ip, &dest_ip);
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int err = pcap_findalldevs(&pcap_if_list, err_buf);
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if (err < 0) {
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pcap_freealldevs(pcap_if_list);
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return -1;
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}
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for (item = pcap_if_list; item != NULL; item = item->next) {
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if (item->addresses == NULL) {
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continue;
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}
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for (struct pcap_addr* pcap_addr = item->addresses; pcap_addr != NULL; pcap_addr = pcap_addr->next) {
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struct sockaddr_in* curr_addr;
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struct sockaddr* sock_addr = pcap_addr->addr;
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if (sock_addr->sa_family != AF_INET) {
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continue;
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}
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curr_addr = ((struct sockaddr_in*)sock_addr);
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if (curr_addr->sin_addr.s_addr == dest_ip.s_addr) {
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strcpy(name_buf, item->name);
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pcap_freealldevs(pcap_if_list);
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return 0;
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}
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}
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}
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pcap_freealldevs(pcap_if_list);
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return -1;
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}
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/*
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* 显示所有的网络接口列表
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*/
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static int pcap_show_list(void) {
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char err_buf[PCAP_ERRBUF_SIZE];
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pcap_if_t* pcapif_list = NULL;
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int count = 0;
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// 查找所有的网络接口
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int err = pcap_findalldevs(&pcapif_list, err_buf);
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if (err < 0) {
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fprintf(stderr, "pcap_show_list: find all net list failed:%s\n", err_buf);
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pcap_freealldevs(pcapif_list);
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return -1;
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}
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printf("pcap_show_list: card list\n");
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// 遍历所有的可用接口，输出其信息
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for (pcap_if_t* item = pcapif_list; item != NULL; item = item->next) {
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if (item->addresses == NULL) {
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continue;
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}
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for (struct pcap_addr* pcap_addr = item->addresses; pcap_addr != NULL; pcap_addr = pcap_addr->next) {
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char str[INET_ADDRSTRLEN];
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struct sockaddr_in* ip_addr;
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struct sockaddr* sockaddr = pcap_addr->addr;
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if (sockaddr->sa_family != AF_INET) {
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continue;
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}
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ip_addr = (struct sockaddr_in*)sockaddr;
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printf("card %d: IP:%s name: %s, \n\n",
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count++,
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item->description == NULL ? "" : item->description,
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inet_ntop(AF_INET, &ip_addr->sin_addr, str, sizeof(str))
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);
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break;
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}
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}
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pcap_freealldevs(pcapif_list);
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if ((pcapif_list == NULL) || (count == 0)) {
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fprintf(stderr, "pcap_show_list: no available card!\n");
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return -1;
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}
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return 0;
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}
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/**
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* 打开pcap设备接口
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* @param ip 打开网卡的指定ip
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* @param 给网卡设置mac
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*/
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pcap_t* pcap_device_open(const char* ip, uint8_t * mac_addr, uint8_t poll_mode) {
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char err_buf[PCAP_ERRBUF_SIZE];
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struct bpf_program fp;
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bpf_u_int32 mask;
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bpf_u_int32 net;
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char filter_exp[256];
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char name_buf[256];
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pcap_t* pcap;
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if (load_pcap_lib() < 0) {
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fprintf(stderr, "pcap_open: load pcap dll failed! install it first\n");
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return (pcap_t*)0;
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}
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if (pcap_find_device(ip, name_buf) < 0) {
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fprintf(stderr, "pcap_open: no net card has ip: %s, use the following:\n", ip);
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pcap_show_list();
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return (pcap_t*)0;
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}
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if (mac_addr == NULL) {
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fprintf(stderr, "pcap_open: mac address buffer is null\n");
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return (pcap_t*)0;
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}
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if (mac_is_zero(mac_addr)) {
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if (read_interface_mac(name_buf, mac_addr) < 0) {
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fprintf(stderr, "pcap_open: failed to query mac address of %s, please configure it manually.\n", name_buf);
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return (pcap_t*)0;
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}
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printf("pcap_open: detected mac %02x:%02x:%02x:%02x:%02x:%02x on %s\n",
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5],
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name_buf);
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fflush(stdout);
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} else {
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if (read_interface_mac(name_buf, mac_addr) < 0) {
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printf("pcap_open: failed to query mac, using configured value %02x:%02x:%02x:%02x:%02x:%02x\n",
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
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fflush(stdout);
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} else {
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printf("pcap_open: overriding configured mac with detected value %02x:%02x:%02x:%02x:%02x:%02x\n",
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
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fflush(stdout);
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}
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}
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if (pcap_lookupnet(name_buf, &net, &mask, err_buf) == -1) {
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printf("pcap_open: can't find use net card: %s\n", name_buf);
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net = 0;
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mask = 0;
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}
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pcap = pcap_open_live(name_buf, // 设置字符串
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65536, // 要捕获的最大字节数
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1, // 混杂模式
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1, // 读取超时（以毫秒为单位）
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err_buf);
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if (pcap == NULL) {
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fprintf(stderr, "pcap_open: create pcap failed %s\n net card name: %s\n", err_buf, name_buf);
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fprintf(stderr, "Use the following:\n");
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pcap_show_list();
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return (pcap_t*)0;
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}
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// 非阻塞模式读取，程序中使用查询的方式读
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if (pcap_setnonblock(pcap, 1, err_buf) != 0) {
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fprintf(stderr, "pcap_open: set none block failed: %s\n", pcap_geterr(pcap));
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return (pcap_t*)0;
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}
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// 只捕获输入，不要捕获自己发出去的
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// 注：win平台似乎不支持这个选项
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if (pcap_setdirection(pcap, PCAP_D_IN) != 0) {
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// fprintf(stderr, "pcap_open: set direction not suppor: %s\n", pcap_geterr(pcap));
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}
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// 只捕获发往本接口与广播的数据帧。相当于只处理发往这张网卡的包
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sprintf(filter_exp,
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"(ether dst %02x:%02x:%02x:%02x:%02x:%02x or ether broadcast) and (not ether src %02x:%02x:%02x:%02x:%02x:%02x)",
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5],
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
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printf("pcap_open: BPF filter: %s\n", filter_exp);
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fflush(stdout);
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if (pcap_compile(pcap, &fp, filter_exp, 0, net) == -1) {
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printf("pcap_open: couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(pcap));
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return (pcap_t*)0;
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}
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if (pcap_setfilter(pcap, &fp) == -1) {
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printf("pcap_open: couldn't install filter %s: %s\n", filter_exp, pcap_geterr(pcap));
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return (pcap_t*)0;
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}
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printf("pcap_open: Filter installed successfully\n");
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fflush(stdout);
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return pcap;
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}
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/**
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* 关闭Pcapif接口
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*/
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void pcap_device_close(pcap_t* pcap) {
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if (pcap == (pcap_t *)0) {
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fprintf(stderr, "pcap = 0");
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pcap_show_list();
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return;
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}
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pcap_close(pcap);
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}
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/**
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* 向网络接口发送数据包
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*/
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uint32_t pcap_device_send(pcap_t* pcap, const uint8_t* buffer, uint32_t length) {
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if (pcap_sendpacket(pcap, buffer, length) == -1) {
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fprintf(stderr, "pcap send: send packet failed!:%s\n", pcap_geterr(pcap));
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fprintf(stderr, "pcap send: pcaket size %d\n", length);
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return 0;
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}
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return 0;
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}
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/**
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* 从网络接口读取数据包
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*/
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uint32_t pcap_device_read(pcap_t* pcap, uint8_t* buffer, uint32_t length) {
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int err;
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struct pcap_pkthdr* pkthdr;
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const uint8_t* pkt_data;
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err = pcap_next_ex(pcap, &pkthdr, &pkt_data);
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if (err == 0) {
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return 0;
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} else if (err == 1) { // 1 - 成功读取数据包, 0 - 没有数据包，其它值-出错
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memcpy(buffer, pkt_data, pkthdr->len);
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return pkthdr->len;
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}
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fprintf(stderr, "pcap_read: reading packet failed!:%s", pcap_geterr(pcap));
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return 0;
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}
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