소켓 예제(Ping)

코드:
/*
Copyright (c) Information Equipment co.,LTD.
Code by JaeHyuk Cho <mailto:minzkn@infoeq.co.kr>

– Simple is best !   (Sequence number check ping)

Bugreport : To JaeHyuk Cho
*/
   
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>

static int __MZ_ICMP_CheckSum__(void *s_Buffer, int s_Size)
{
   int s_Return = 0;
   
   if(s_Size & 1)
       s_Return += (int)((*(unsigned char *)s_Buffer)++);
   
   s_Size >>= 1;
   
   while(s_Size– > 0)
       s_Return += (int)(*(((unsigned short *)s_Buffer)++));
   
   if(s_Size == 1)
       s_Return += (int)(*(unsigned char *)(s_Buffer));
   
   s_Return  = (s_Return >> 16) + (s_Return & 0xFFFF);
   s_Return += (s_Return >> 16);
   
   return((~s_Return) & 0xffff);
}

int CORE_Ping(const char *s_HostName, unsigned int s_Index, unsigned int s_TimeOut)
{
   int                      s_Return = (-1), s_Socket, s_SendBytes, s_RecvBytes, s_IsSelect;
   struct protoent        *s_ProtoEntry;
   struct hostent        *s_HostEntry;
   struct sockaddr_in     s_PingAddress, s_FromAddress;
   socklen_t             s_FromAddressLength;
   struct icmp            *s_ICMP;
   struct iphdr          *s_IPHeader;
   unsigned char         s_ICMP_Packet[ 60 + 76 + 56 ]; /* Packet assembly */
   fd_set                   s_FD;
   struct timeval           s_TimeVal;
   s_HostEntry = gethostbyname(s_HostName);
   
   if(s_HostEntry)
   {
       memset((void *)(&s_PingAddress), 0, sizeof(s_PingAddress));
       s_PingAddress.sin_family = AF_INET;
       memcpy((void *)(&s_PingAddress.sin_addr), s_HostEntry->h_addr, sizeof(s_PingAddress.sin_addr));
       memset((void *)(&s_ICMP_Packet[0]), 0, sizeof(s_ICMP_Packet));
       s_ICMP = (struct icmp *)(&s_ICMP_Packet[0]);
       s_ICMP->icmp_type  = ICMP_ECHO;
       s_ICMP->icmp_seq   = s_Index;
       s_ICMP->icmp_id    = getpid() & 0xffff;
       gettimeofday((struct timeval *)(&s_ICMP_Packet[8]), (void *)0);
       s_ICMP->icmp_cksum = __MZ_ICMP_CheckSum__((void *)(&s_ICMP_Packet[0]), sizeof(s_ICMP_Packet));
       s_ProtoEntry = getprotobyname(“icmp”);
       s_Socket = socket(AF_INET, SOCK_RAW, s_ProtoEntry ? s_ProtoEntry->p_proto : 1);
       setuid(getuid()); /* Who are you ? */
   
       if(s_Socket >= 0)
       {
           s_SendBytes = sendto(s_Socket, (void *)(&s_ICMP_Packet[0]), sizeof(s_ICMP_Packet),
                                   MSG_NOSIGNAL, /* Ignore broken pipe */
                                   (struct sockaddr *)(&s_PingAddress), sizeof(s_PingAddress));
           
           if(s_SendBytes == sizeof(s_ICMP_Packet))
           {
               memset((void *)(&s_FromAddress), 0, sizeof(s_FromAddress));
               s_FromAddressLength = sizeof(s_FromAddress);
               memset((void *)(&s_ICMP_Packet[0]), 0, sizeof(s_ICMP_Packet));
               s_TimeVal.tv_sec = s_TimeOut, s_TimeVal.tv_usec = 0;
               FD_ZERO(&s_FD);
               FD_SET(s_Socket, &s_FD);
               s_IsSelect = select(s_Socket + 1, &s_FD, (fd_set *)0, (fd_set *)0, &s_TimeVal);
           
               if(s_IsSelect > 0 && FD_ISSET(s_Socket, &s_FD) != 0)
               {
                   s_RecvBytes = recvfrom(s_Socket, (void *)(&s_ICMP_Packet[0]), sizeof(s_ICMP_Packet),
                                           MSG_NOSIGNAL, /* Ignore broken pipe */
                                           (struct sockaddr *)(&s_FromAddress), (socklen_t *)(&s_FromAddressLength));
               }
               else
                   s_RecvBytes = 0;
                                   
               if(s_RecvBytes >= 76)
               {
                   s_IPHeader = (struct iphdr *)(&s_ICMP_Packet[0]);
                   s_ICMP = (struct icmp *)(&s_ICMP_Packet[ s_IPHeader->ihl << 2 ]);
                       if(s_ICMP->icmp_type == ICMP_ECHOREPLY)
                       {
                           /* TODO:
                           Packet check sum need
                           Time compute
                           Duplicate packet check
                           Send packet & Recv packet -> Two thread or alarm
                           */
                           s_Return = (int)s_ICMP->icmp_seq;
                       }
               }
           }
           close(s_Socket);
       }
   }
   
   return(s_Return);
}

int main(int s_Argc, char *s_Argv[])
{
   int s_Return, s_Check, s_Index, s_ErrorCount, s_IsError, s_Count;
   fprintf(stdout, “MZ_Ping v0.0.1 – Code by JaeHyuk Cho <minzkn@infoeq.co.kr>\n\n”);
   
   if(s_Argc > 1)
   {
       s_ErrorCount = 0, s_Index = 1;
       
       if(s_Argc > 2)
           sscanf(s_Argv[2], “%i”, &s_Count);
       else
           s_Count = 8;
       
       do
       {
           s_Check = CORE_Ping(s_Argv[1], s_Index /* Request sequence number */, 4u /* Timeout 4 second */);
           
           if(s_Check != s_Index)
               s_ErrorCount++, s_IsError = 1;
           else
               s_IsError = 0;
           
           fprintf(stdout, “Ping[%s]: %s (Seq %d->%d) – ERR=%d\n”,
           s_Argv[1], s_IsError == 0 ? “OK” : “LOSS”, s_Index, s_Check, s_ErrorCount);
           usleep(10000);
       }while(s_Index++ < s_Count);
       
       fprintf(stdout, “Total %d%% loss.\n”, s_ErrorCount * 100 / s_Index);
       s_Return = s_ErrorCount;
   }
   else
   {
       fprintf(stdout, “usage: ping <host> <count>\n”);
       s_Return = 0;
   }
   return(s_Return);
}

/* End of source */