SO_BINDTODEVICE problem

Hi everybody;
I try to generate a server client code. What i try to do is sending video streams from eth0 and eth1 to the other server programs' eth0 and eth1. In order to do that, i decided to use SO_BINDTODEVICE. But the code is not working. Am i misunderstood the usage of SO_BINDTODEVICE.
1-Defining two ports
2-Defining two sockets
3-Assigning host ips on them
4-Bind two sockets to two ethernet out
5-Send them to two differnet ethernet on server

Thanks in advance.

Code:

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//CLIENT
 #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <errno.h>
    #include <string.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <netdb.h>

    #define MYPORT 4965  // the port users will be connecting to
    #define MYPORT2 4962
    int main(int argc, char *argv[])
    {
        int sockfd,i,result2;
        int sockfd2;
        struct sockaddr_in their_addr; // connector's address information
        struct hostent *he,*he2;
        struct sockaddr_in their_addr2; // connector's address information
        int numbytes;
        int numbytes2;

        if (argc != 3) {
            fprintf(stderr,"%d usage: talker hostname message\n",argc);
            exit(1);
        }
        if ((he=gethostbyname(argv[1])) == NULL) {  // get the host info
            perror("gethostbyname");
            exit(1);
        }

        if ((he2=gethostbyname(argv[2])) == NULL) {  // get the host info
            perror("gethostbyname");
            exit(1);
        }
       
        if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
            perror("socket");
            exit(1);
        }
        if ((sockfd2 = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
                    perror("socket");
                    exit(1);
                }

        // bind a socket to a device name (might not work on all systems):
        char *optval2;
        optval2 = "eth1"; // 4 bytes long, so 4, below:
        setsockopt(sockfd, IPPROTO_UDP, SO_BINDTODEVICE, optval2, 4);

        char *optval1;
                optval1 = "eth2"; // 4 bytes long, so 4, below:
                setsockopt(sockfd2, IPPROTO_UDP, SO_BINDTODEVICE, optval1, 4);

        their_addr.sin_family = AF_INET;    // host byte order
        their_addr.sin_port = htons(MYPORT); // short, network byte order
        their_addr.sin_addr = *((struct in_addr *)he->h_addr);
        memset(&(their_addr.sin_zero), '\0', 8); // zero the rest of the struct

        their_addr2.sin_family = AF_INET;    // host byte order
              their_addr2.sin_port = htons(MYPORT2); // short, network byte order
              their_addr2.sin_addr = *((struct in_addr *)he2->h_addr);
              memset(&(their_addr2.sin_zero), '\0', 8); // zero the rest of the struct

        FILE *file_path;
              file_path=fopen("/home/fatih/Desktop/MoDeo/Underworld.Evolution.1080p.Blu-Ray.MPEG-2.HRT_Sample.ts","r");
        char * ch, * ch2;
        int count=188;

        long lSize;
        size_t result;
        fseek (file_path , 0 , SEEK_END);
          lSize = ftell (file_path);
          rewind (file_path);

          // allocate memory to contain the whole file:
        ch = (char*) malloc (sizeof(char)*lSize);
          if (ch == NULL) {fputs ("Memory error",stderr); exit (2);}


          ch2 = (char*) malloc (sizeof(char)*lSize);
                  if (ch2 == NULL) {fputs ("Memory error",stderr); exit (2);}

          // copy the file into the buffer:

          result = fread (ch,1,lSize,file_path);
          printf("%ld",lSize);

          int b=0;
                long  k=0;
          while(k<=lSize){

          for(i=0;i<188;i++){
                  ch2[i]=ch[k];
                    k++;

          }                  if ((numbytes=sendto(sockfd,ch2, 188, 0,
                              (struct sockaddr *)&their_addr, sizeof(struct sockaddr))) == -1) {
                            perror("sendto");
                            exit(1);
                        }

          for(i=0;i<188;i++){
                            ch2[i]=ch[k];
                                        k++;

          }
                            if ((numbytes2=sendto(sockfd2,ch2, 188, 0,
                                        (struct sockaddr *)&their_addr2, sizeof(struct sockaddr))) == -1) {
                                      perror("sendto");
                                      exit(1);
                                  }
          }

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