不发送原始套接字 [英] Raw socket NOT sending

问题描述

我试图写一个样品原始套接字程序来清除我的原始套接字的理解。我创建了一个原始UDP套接字，然后调用SENDTO。我的sendto成功，但我从来没有看到对方接收的数据包。我没有收到任何端运行，所以我依靠Wireshark的发送方和接收方运行。
我在这里粘贴code片段。请指出任何错误。

I am trying to write a sample Raw socket program to clear my understanding of raw sockets. I create a Raw UDP socket and then call sendto. My sendto succeeds but I never see the packet received by the other side. I don't have any receive side running so I am relying on Wireshark running on both the sender and receiver. I am pasting the code snippet here. Please point out any errors.

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<string.h>

#include "protHeaders.x"
#include "gen.h"

U16 csum(U16* buf, S32 nwords)
  {
   U32 sum;
   for (sum = 0; nwords > 0; nwords--)
     sum += *buf++;
   sum = (sum >> 16) + (sum & 0xffff);
   sum += (sum >> 16);


   return ~sum;
  }/*csum*/

 int main(int argc,char** argv)
  {
    U8 datagram[MAX_IPPACKET];
    U8 udpPayLoad[MAX_UDPPAYLOAD];
    CustIpHeader* ipH;
    CustUdpHeader* udpH;
    struct sockaddr_in sin;
    S32 sockFd;
    S32 one = 1;
    const S32* val = &one;


   ipH   = (CustIpHeader *)datagram;
   udpH  = (CustUdpHeader *)(datagram + sizeof(CustIpHeader));

   memset(datagram,0,sizeof(datagram));
   memset(udpPayLoad,0,sizeof(udpPayLoad));
   memset(&sin,0,sizeof(struct sockaddr_in));

   strcpy(udpPayLoad,"<<<<Aditya>>>>");

   sin.sin_family = AF_INET;
   sin.sin_port   = htons(atoi(argv[4]));

   /* fill the Ip header */

    ipH->ip_hl         = 5;
    ipH->ip_v          = 4;
    ipH->ip_tos        = 0;
    ipH->ip_len        = sizeof(CustIpHeader) + sizeof(CustUdpHeader) + strlen(udpPayLoad);
    ipH->ip_id         = htonl(54321);
    ipH->ip_off        = 0;
    ipH->ip_p          = 17;
    ipH->ip_ttl        = 65;
    ipH->ip_sum        = 0;
    ipH->ip_src.s_addr = inet_addr(argv[1]);
    ipH->ip_dst.s_addr = inet_addr(argv[3]);

  /* fill the Udp header */

    udpH->uh_sport     = htons(atoi(argv[2]));
    udpH->uh_dport     = htons(atoi(argv[4]));
    udpH->uh_len       = sizeof(CustUdpHeader) + strlen(udpPayLoad);
    udpH->uh_check     = 0;

   printf("Checksum = %u\n",udpH->uh_check);
  /* copy udpPayLoad */
    strcpy(datagram+sizeof(CustIpHeader)+sizeof(CustUdpHeader),udpPayLoad);
   #if 1
    printf("Datagram %p,UdpPayload %p\n",(void *)datagram,(void *)datagram+sizeof(CustIpHeader)+sizeof(CustUdpHeader));
    printf("IpHeader %p, UdpHeader %p\n",(void *)ipH,udpH);
   #endif

  /* fill in the checksum */

   ipH->ip_sum = csum((U16 *)datagram,ipH->ip_len >> 1);

   printf("Checksum = %u\n",ipH->ip_sum);


  if ((sockFd = socket(PF_INET,SOCK_RAW,IPPROTO_UDP)) < 0)
      {
         perror("socket:create");
         RETURN(RFAILED);
      }
  /* doing the IP_HDRINCL call */

    if (setsockopt(sockFd,IPPROTO_IP,IP_HDRINCL,val,sizeof(one)) < 0)
     {
        perror("Client:setsockopt");
     }


   while(1)
    {
      if ( sendto(sockFd,
                  datagram,
                  ipH->ip_len,
                  0,
                  (struct sockaddr *)&sin,
                  sizeof (sin)) < 0)
           { perror("Client:sendto"); }

      else
           printf(".");

    }

   RETURN(ROK);
  }

在IP和UDP报头是：

The IP and UDP headers are:

typedef struct _ipheader
 {
   U8 ip_hl:4,ip_v:4; /* ip_hl: the ip header length in 32bit octets.
                       * ip_v : ip version (always 4 for our case).
                       */

   U8 ip_tos;         /* reliability of the service. 0x00 is Normal */

   U16 ip_len;        /* totoal length including ip header,icmp/tcp/udp header
                       * and payload size in bytes
                       */

   U16 ip_id;         /* sequence no. used for reassembly of fragmented IP packets */

   U16 ip_off;        /* the fragment offset used for reassembly of fragmented packets */

   U16 ip_p;          /* the transport layer protocol. can be tcp (6), udp(17) */


   U8 ip_ttl;         /* time to live */

   U16 ip_sum;        /* the datagram checksum for the whole IP packet */

   struct in_addr ip_src;        /* the source IP address, converted to a long format */

   struct in_addr ip_dst;        /* the desitnation IP address, converted to a long format */
 }CustIpHeader; /* total ip header length: 20 bytes */



typedef struct _udpheader
{

 U16 uh_sport;      /* The source port that a client bind()s to */
 U16 uh_dport;      /* The desination port that a server bind()s to*/
 U16 uh_len;        /* The length of udp header and payload data in bytes */
 U16 uh_check;      /* The checksum of header and data */

}CustUdpHeader; /* total udp header length: 8 bytes (=64 bits) */

我正在用root用户，这样的特权是没有问题的。

I am running as root user, so privileges is not a problem.

语言：C

操作系统：Linux

Os: Linux

推荐答案

我有一个缓慢的系统上运行Wireshark的。这些数据包被确实发送，但Wireshark的只能6分钟左右的差距后，给他们。迁移到更快的系统帮助。因此，我将结束这个自己。

I had the wireshark running on a slow system. The packets were indeed being send but the Wireshark could only show them after a gap of 6 minutes or so. Moving to a faster system helped. I am therefore closing this myself.

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