編譯時的PCAP程序錯誤

Question

這是一個從網絡適配器獲取源地址和目標地址的程序。當嘗試編譯以下程序時，我被留下了錯誤。 有人對這些錯誤有想法嗎？

 #include <stdio.h>
    #include <conio.h>
    #include "packet32.h"
    #include <ntddndis.h>
     #include <stdint.h> 
    #include <cstdint>
    #define PCAP_DONT_INCLUDE_PCAP_BPF_H
    #include<pcap.h>

    #define SIZE_ETHERNET 14
    #define ETHER_ADDR_LEN  6
    #define PCAP_ERRBUF_SIZE 30

    /* Ethernet header */
        struct sniff_ethernet {
            u_char ether_dhost[ETHER_ADDR_LEN]; /* Destination host address */
            u_char ether_shost[ETHER_ADDR_LEN]; /* Source host address */
            u_short ether_type; /* IP? ARP? RARP? etc */
        };
        struct bpf_program {
        u_int bf_len;
        struct bpf_insn *bf_insns;
    };

        /* IP header */
        struct sniff_ip {
            u_char ip_vhl;      /* version << 4 | header length >> 2 */
            u_char ip_tos;      /* type of service */
            u_short ip_len;     /* total length */
            u_short ip_id;      /* identification */
            u_short ip_off;     /* fragment offset field */
        #define IP_RF 0x8000        /* reserved fragment flag */
        #define IP_DF 0x4000        /* dont fragment flag */
        #define IP_MF 0x2000        /* more fragments flag */
        #define IP_OFFMASK 0x1fff   /* mask for fragmenting bits */
            u_char ip_ttl;      /* time to live */
            u_char ip_p;        /* protocol */
            u_short ip_sum;     /* checksum */
            struct in_addr ip_src;
            struct in_addr ip_dst; /* source and dest address */
        };
        #define IP_HL(ip)       (((ip)->ip_vhl) & 0x0f)
        #define IP_V(ip)        (((ip)->ip_vhl) >> 4)

        /* TCP header */

        typedef __int32 int32_t;
    typedef unsigned __int32 u_int32_t;
        struct sniff_tcp {
            u_short th_sport;   /* source port */
            u_short th_dport;   /* destination port */
            u_int32_t th_seq;       /* sequence number */
            u_int32_t th_ack;       /* acknowledgement number */

            u_char th_offx2;    /* data offset, rsvd */
        #define TH_OFF(th)  (((th)->th_offx2 & 0xf0) >> 4)
            u_char th_flags;
        #define TH_FIN 0x01
        #define TH_SYN 0x02
        #define TH_RST 0x04
        #define TH_PUSH 0x08
        #define TH_ACK 0x10
        #define TH_URG 0x20
        #define TH_ECE 0x40
        #define TH_CWR 0x80
        #define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
            u_short th_win;     /* window */
            u_short th_sum;     /* checksum */
            u_short th_urp;     /* urgent pointer */
    };

    int main(int argc, char *argv[])
    {

        //get file
         char *filename = argv[1];

         //error buffer
         char errbuff[PCAP_ERRBUF_SIZE];

         //open file and create pcap handler
         pcap_t * handler = pcap_open_offline(filename, errbuff);

         //The header that pcap gives us
        struct pcap_pkthdr *header;

        //The actual packet 
        const u_char *packet;   

          int packetCount = 0;
          int i;

          //write to file 
          FILE *fp = fopen ( "result.txt", "w" ) ;

          //tcp info
        const struct sniff_ethernet *ethernet; /* The ethernet header */
        const struct sniff_ip *ip; /* The IP header */
        const struct sniff_tcp *tcp; /* The TCP header */
        u_int size_ip;
        u_int size_tcp;

        while (pcap_next_ex(handler, &header, &packet) >= 0)
        {
            // Show the packet number
            printf("Packet # %i\n", ++packetCount);
            fprintf(fp,"Packet # %i\n", packetCount);

            // Show the size in bytes of the packet
            printf("Packet size: %d bytes\n", header->len);
            fprintf(fp,"Packet size: %d bytes\n", header->len);

            // Show a warning if the length captured is different
            if (header->len != header->caplen)
                printf("Warning! Capture size different than packet size: %ld bytes\n", header->len);

            // Show Epoch Time
            printf("Epoch Time: %d:%d seconds\n", header->ts.tv_sec, header->ts.tv_usec);
            fprintf(fp,"Epoch Time: %d:%d seconds\n", header->ts.tv_sec, header->ts.tv_usec);

            ethernet = (struct sniff_ethernet*)(packet);
            ip = (struct sniff_ip*)(packet + SIZE_ETHERNET);
            size_ip = IP_HL(ip)*4;
            if (size_ip < 20) {
                printf("   * Invalid IP header length: %u bytes\n", size_ip);
                return;
            }
            tcp = (struct sniff_tcp*)(packet + SIZE_ETHERNET + size_ip);

            printf("src port: %d dest port: %d \n", tcp->th_sport, tcp->th_dport);
            fprintf(fp,"src port: %d dest port: %d \n", tcp->th_sport, tcp->th_dport);

            printf("src address: %s dest address: %s \n",  inet_ntoa(ip->ip_src),  inet_ntoa(ip->ip_dst));
            fprintf(fp,"src address: %s dest address: %s \n",  inet_ntoa(ip->ip_src),  inet_ntoa(ip->ip_dst));

            printf("seq number: %u ack number: %u \n", (unsigned int)tcp-> th_seq, (unsigned int)tcp->th_ack);
            fprintf(fp,"seq number: %u ack number: %u \n", (unsigned int)tcp-> th_seq, (unsigned int)tcp->th_ack);

            // Add two lines between packets
            printf("\n");
            fprintf(fp,"\n");
        }
        fclose (fp);
         return(0);
    }

以下是導致的錯誤

1>------ Build started: Project: qqq, Configuration: Release Win32 ------
1>Build started 6/1/2015 5:27:54 PM.
1>InitializeBuildStatus:
1>  Touching "Release\qqq.unsuccessfulbuild".
1>ClCompile:
1>  test1.c
1>test1.c(12): warning C4005: 'PCAP_ERRBUF_SIZE' : macro redefinition
1>          C:\Users\Sathwik\Desktop\AirCap\developers\WinPcap_Devpack\Include\pcap/pcap.h(76) : see previous definition of 'PCAP_ERRBUF_SIZE'
1>test1.c(20): error C2011: 'bpf_program' : 'struct' type redefinition
1>          C:\Users\Sathwik\Desktop\AirCap\developers\WinPcap_Devpack\Include\packet32.h(109) : see declaration of 'bpf_program'
1>test1.c(126): error C2561: 'main' : function must return a value
1>          test1.c(72) : see declaration of 'main'
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:00.34
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

您的代碼有兩個問題。

1. 除非您使用packet.dll例程之一，否則不要包括“ packet32.h”。 您僅使用WinPcap例程，因此不需要包括“ packet32.h”，將其刪除將擺脫“'PCAP_ERRBUF_SIZE'：宏重新定義”警告和“'bpf_program'：'struct'類型重新定義”的警告錯誤。 （如果不需要，則不要使用packet.dll例程，並且在程序中也不需要。）也不需要包含“”。

   另外， 請勿定義PCAP_DONT_INCLUDE_PCAP_BPF_H ！ 這是我添加到libpcap中的一種技巧， 僅在編譯libpcap內部的一些代碼時使用； 用戶切勿定義它。

2. “'main'：函數必須返回值”表示名為main()的函數必須返回值； 即，函數必須在其返回的所有位置（ 包括代碼中）返回值

     size_ip = IP_HL(ip)*4; if (size_ip < 20) { printf(" * Invalid IP header length: %u bytes\\n", size_ip); return; } 

   所以你必須說return(1); 或諸如此類的東西，而不僅僅是return; 。