void icmp_in(struct pkbuf *pkb)
{
struct ip *iphdr = pkb2ip(pkb);
struct icmp *icmphdr = ip2icmp(iphdr);
int icmplen, type;
/* sanity check */
icmplen = ipdlen(iphdr);
icmpdbg("%d bytes", icmplen);
if (icmplen < ICMP_HRD_SZ) {
icmpdbg("icmp header is too small");
goto drop_pkb;
}
if (icmp_chksum((unsigned short *)icmphdr, icmplen) != 0) {
icmpdbg("icmp checksum is error");
goto drop_pkb;
}
type = icmphdr->icmp_type;
if (type > ICMP_T_MAXNUM) {
icmpdbg("unknown icmp type %d code %d",
type, icmphdr->icmp_code);
goto drop_pkb;
}
/* handle icmp type */
icmp_table[type].handler(&icmp_table[type], pkb);
return;
drop_pkb:
free_pkb(pkb);
}
static void recv_packet(void)
{
struct pkbuf *pkb;
struct ip *iphdr;
struct icmp *icmphdr;
while (!finite || recv > 0) {
pkb = _recv(sock);
if (!pkb)
break;
iphdr = pkb2ip(pkb);
icmphdr = ip2icmp(iphdr);
if (iphdr->ip_pro == IP_P_ICMP &&
_ntohs(icmphdr->icmp_id) == id &&
icmphdr->icmp_type == ICMP_T_ECHORLY) {
recv--;
printf("%d bytes from " IPFMT ": icmp_seq=%d ttl=%d\n",
ipdlen(iphdr), ipfmt(iphdr->ip_src),
_ntohs(icmphdr->icmp_seq), iphdr->ip_ttl);
precv++;
}
free_pkb(pkb);
}
}
