UDP echo client/server

Hi
I have written the following UDP echo client / server code using recvmsg and sendmsg. But unfortunately no words are echoed back. How should I modify the code

//UDP echo client code
#include     "unp.h"
#include <stdio.h>
#include <sys/socket.h>
#undef MAXLINE
#define MAXLINE 256

 int main(int argc, char **argv)
 {
    int     sockfd;
    struct sockaddr_in servaddr;

     if(argc != 2)
        err_quit("usage: udpcli <IPaddress>");

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(SERV_PORT);
    Inet_pton(AF_INET, argv[1], &servaddr.sin_addr);

    sockfd = Socket(AF_INET, SOCK_DGRAM, 0);

    dg_cli(stdin, sockfd, (SA *) &servaddr, sizeof(servaddr));

    exit(0);
 }

 void dg_cli(FILE *fp, int sockfd, const SA *pservaddr, socklen_t servlen)
 {
     int     n, i;
     char    sendline[MAXLINE], recvline[MAXLINE + 1];
       struct msghdr msg;
       struct iovec iov[100],iov1[1];      

     while (Fgets(sendline, MAXLINE, fp) != NULL)
       {
            
            msg.msg_name            = (void *)pservaddr;
            msg.msg_namelen         = servlen ;
            iov1[0].iov_base        = recvline;
            iov1[0].iov_len         = MAXLINE;
            msg.msg_iov             = iov;
            msg.msg_iovlen          = 1;
            sendmsg(sockfd, &msg, 0);
            n=recvmsg(sockfd, &msg, 0);
            recvline[n] = 0;        /* null terminate */
                                          Fputs(recvline, stdout);    
      }
 }

//UDP echo server code
#include     "unp.h"
#include <stdio.h>
#include <sys/socket.h>



 int main(int argc, char **argv)
 {
     int     sockfd;
     struct sockaddr_in servaddr, cliaddr;
      
     sockfd = Socket(AF_INET, SOCK_DGRAM, 0);

     bzero(&servaddr, sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
     servaddr.sin_port = htons(SERV_PORT);

     Bind(sockfd, (SA *) &servaddr, sizeof(servaddr));

     dg_echo(sockfd, (SA *) &cliaddr, sizeof(cliaddr));
 }

 void dg_echo(int sockfd, SA *pcliaddr, socklen_t clilen)
 {
     int     n;
     socklen_t len;
       char    recvline[MAXLINE];
       struct msghdr msg;
     struct iovec iov[100],iov1[1];
             
     for ( ; ; ) {
            
        msg.msg_name            = (void *)pcliaddr;
            msg.msg_namelen         = clilen;
            iov1[0].iov_base         = recvline;
            iov1[0].iov_len          = MAXLINE ;
            msg.msg_iov             = iov;
            msg.msg_iovlen          = 1;        
            n = recvmsg(sockfd ,&msg, 0);
        sendmsg(sockfd, &msg, 0);
            
     
     }
 }

Error: The input I give isn't being echoed.

Pls help and let me know what modifications I need to make to make the program run.