Raw 소켓을 사용한 ping 프로그램 오류가 나요 ㅜㅜ

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#define BUFSIZE 1500
char sendbuf[BUFSIZE], recvbuf[BUFSIZE];
int seqnum;
pid_t pid;
int sockfd;
int datalen = 56;
struct sockaddr_in dstaddr, srcaddr;
int send_ping();
int print_ping(char *ipdata, int readlen);
void sig_alrm(int);
void tv_sub(struct timeval *, struct timeval *);
uint16_t in_cksum(uint16_t *addr, int len);
void error_print(char *);
int main(int argc, char **argv){
  int readlen, addrlen;
  if(argc!=2){
    printf("Usage : %s ip_address \n", argv[0]);
    exit(1);
  }
  bzero(&srcaddr, sizeof(struct sockaddr));
  bzero(&dstaddr, sizeof(struct sockaddr));
  dstaddr.sin_family = AF_INET;
  dstaddr.sin_addr.s_addr = inet_addr(argv[1]);
  dstaddr.sin_port = htons(0);
  sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
  if(sockfd < 0)
    error_print("raw socket creation fail.");
  if(connect(sockfd, (struct sockaddr *)&dstaddr,
    sizeof(struct sockaddr))!=0 )
    error_print("connect for raw socket fail.");
  pid = getpid() & 0xffff;
  signal(SIGALRM, sig_alrm);
  addrlen = sizeof(srcaddr);
  sig_alrm(SIGALRM);
  while(1){
    readlen = recvfrom(sockfd, recvbuf, sizeof(recvbuf),0,(struct sockaddr *)&srcaddr, &addrlen);
    if(readlen < 0)
      error_print("recvfrom() error");
    print_ping(recvbuf, readlen);
  }
  exit(0);
}
uint16_t in_cksum(uint16_t *addr, int len){
  int nleft = len;
  uint32_t sum = 0;
  uint16_t *w = addr;
  uint16_t 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);
}
int send_ping(){
  int len;
  struct icmp *icmp;
  icmp = (struct icmp *) sendbuf;
  bzero((char *)icmp, sizeof(struct icmp));
  icmp->icmp_type = ICMP_ECHO;
  icmp->icmp_code = 0;
  icmp->icmp_id = pid;
  icmp->icmp_seq = seqnum++;
  memset(icmp->icmp_data, 0xa5, datalen);
  gettimeofday((struct timeval *)icmp->icmp_data,NULL); 
  len = 8 + datalen;
  icmp->icmp_cksum = 0;
  icmp->icmp_cksum = in_cksum((u_short *) icmp, len);
  sendto(sockfd, sendbuf, len, 0, (struct sockaddr *)&dstaddr, sizeof(dstaddr));
}
void sig_alrm(int signo){
  send_ping();
  alarm(2);
  return;
}
void tv_sub(struct timeval *out, struct timeval *in){
  if ((out->tv_usec -= in->tv_usec) < 0){
    --out->tv_sec;
    out->tv_sec += 1000000;
    }
    out->tv_sec -= in->tv_sec;
}
print_ping(char *ipdata, int recvsize){
  int ip_headlen, icmp_len;
  double rtt;
  struct icmp *icmp;
  struct iphdr *ip;
  struct timeval *tvsend, tvrecv;
  char buf[512];
  gettimeofday(&tvrecv, NULL);
  ip = (struct iphdr *) ipdata;
  ip_headlen = ip->ihl *4;
  if(ip->protocol != IPPROTO_ICMP){
    printf("not ICMP packet.\n");
    return;
  }
  icmp = (struct icmp *) (ipdata + ip_headlen);
  icmp_len = recvsize - ip_headlen;
  tvsend = (struct timeval *)icmp->icmp_data;
  tv_sub(&tvrecv, tvsend);
  rtt = tvrecv.tv_sec * 1000.0 + tvrecv.tv_usec / 1000.0;
  inet_ntop(AF_INET, (void *)&ip->saddr, buf, sizeof(buf));
  printf("%d bytes recv from %s: seq = %u, ttl = %d, rtt = %.3fms\n",
    icmp_len, buf, icmp->icmp_seq, ip->ttl, rtt);
}
void error_print(char *message){
  fputs(message, stderr);
  fputc('\n', stderr);
  exit;
}