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Old 06-08-2010, 01:54 AM   #1
LQ Newbie
Registered: Jun 2010
Posts: 3

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Problem wid RAW Sockets

this is the code that i made for the raw socket at the client wen i run this code and try to capture the packet through wireshak there is no packet captured...there is no error in the code...

#include <string.h>
#include <netdb.h>
#include <sys/types.h>

struct ipheader
unsigned char iph_ihl,iph_ver;
unsigned char iph_tos;
unsigned short iph_len;
unsigned short iph_ident;
unsigned char iph_flag;
unsigned short iph_offset;
unsigned char iph_ttl;
unsigned char iph_protocol;
unsigned short iph_chksum;
unsigned int iph_sourceip;
unsigned int iph_destip;

struct udpheader
unsigned short udph_srcport;
unsigned short udph_destport;
unsigned short udph_len;
unsigned short udph_chksum;

struct psd_udp {
struct in_addr src;
struct in_addr dst;
unsigned char pad;
unsigned char proto;
unsigned short udp_len;
struct udpheader udp;

unsigned short in_cksum(unsigned short *addr, int len)
int nleft = len;
int sum = 0;
unsigned short *w = addr;
unsigned short answer = 0;

while (nleft > 1) {
sum += *w++;
nleft -= 2;

if (nleft == 1) {
*(unsigned char *) (&answer) = *(unsigned char *) w;
sum += answer;

sum = (sum >> 16) + (sum & 0xFFFF);
sum += (sum >> 16);
answer = ~sum;
return (answer);

unsigned short in_cksum_udp(int src, int dst, unsigned short *addr, int len)
struct psd_udp buf;

memset(&buf, 0, sizeof(buf));
buf.src.s_addr = src;
buf.dst.s_addr = dst;
buf.pad = 0;
buf.proto = IPPROTO_UDP;
buf.udp_len = htons(len);
memcpy(&(buf.udp), addr, len);
return in_cksum((unsigned short *)&buf, 12 + len);

int main(int argc,char **argv)
int sd;
char *buffer;
struct ipheader ip;
struct udpheader udp;
struct sockaddr_in sin;
int one = 1,i=0;
const int *val = &one;
if(argc != 6)

printf("- Invalid parameters!!!\n");

printf("- Usage %s <source hostname/IP> <source port> <target hostname/IP> <target port>\n", argv[0]);
sin.sin_family = AF_INET;
sin.sin_port = atoi(argv[4]);
sin.sin_addr.s_addr = inet_addr(argv[3]);
ip.iph_ihl = 5;
ip.iph_ver = 4;
ip.iph_tos =0;
ip.iph_len =60;
ip.iph_chksum=in_cksum((unsigned short *)&ip, sizeof(ip));
ip.iph_ident = htons(54321);
ip.iph_ttl = 64; // hops
ip.iph_protocol = 17;
ip.iph_sourceip = inet_addr(argv[1]);
ip.iph_destip = inet_addr(argv[3]);
printf("%d \t %d \t %d \t %d\n",sizeof(ip),sizeof(udp),strlen(buffer),sizeof(buffer));
udp.udph_srcport = htons(atoi(argv[2]));
udp.udph_destport = htons(atoi(argv[4]));
udp.udph_len = htons(8);
udp.udph_chksum=in_cksum_udp(ip.iph_sourceip,ip.iph_destip,(unsigned short *)&udp,sizeof(udp));
printf("%d \t %d \t %d \t %d\n",sizeof(ip),sizeof(udp),strlen(buffer),sizeof(buffer));
if(sd < 0)
perror("socket() error");
printf("socket() - Using SOCK_RAW socket and UDP protocol is OK.\n");
if(setsockopt(sd, IPPROTO_IP, IP_HDRINCL, val, sizeof(one)) < 0)
perror("setsockopt() error");
printf("setsockopt() is OK.\n");
if(sendto(sd,buffer,60,0,(struct sockaddr *)&sin,sizeof(struct sockaddr))<0)
printf("\n Error in sending:");
else printf("\n sent %s",argv[5]);
return 0;

sumbudy tell me wat modifications i shud made in the above code...
plzz any one help me...thnx in advance..!
Old 06-08-2010, 03:00 AM   #2
Registered: Apr 2010
Location: Johannesburg
Distribution: Fedora 14, RHEL 5.5, CentOS 5.5, Ubuntu 10.04
Posts: 559

Rep: Reputation: 92

Welcome to LQ!

The reason that your post is not getting responses is due to the way you're asking your question. Please read the LQ Rules and "How to ask Questions the Smart Way" - see the sticky at the top of this forum.

What you've posted is a pretty substantial C program, and most of the members will not have the time to analyze your code and find the problem for you.

At LQ we encourage people to help themselves; with the assistance of the community. My advice to you is to identify the section of code that is giving you trouble; and explain exactly what the symptoms/problem itself is.
Old 06-08-2010, 10:26 AM   #3
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Raw sockets require root privileges. Do you have that? If so, then tell us why you think there is no error in the code. There is an error in the way you posted your code. Please use [CODE] tags, especially for a large volume of code like you have posted.

By the way, you are asking people for help, and at some level that implies that the people are knowledgeable and probably educated. Those people usually like to read language that can be found in a dictionary.

--- rod.

Last edited by theNbomr; 06-08-2010 at 10:32 AM.


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