IP Range To CIDR Convertor
// Convert a given Ip range to CIDR notation.
# cat rangeToCidr
/* rangeToCidr.c - Convert Ip ranges to CIDR */
/*
modification history http://snippets.dzone.com/tag/cidr
--------------------
,17sep08,karn written
*/
/* includes */
#include
#include
#include
#include
#include
#include
#include
#include
/* defines */
//#define DBG
#ifdef DBG
#define DEBUG(x) fprintf(stderr,x)
#else
#define DEBUG
#endif /* DBG */
#define IP_BINARY_LENGTH 32+1 /* 32 bits ipv4 address +1 for null */
#define IP_HEX_LENGTH 10
#define MAX_CIDR_MASK 32
#define MAX_CIDR_LEN 18+1 /*255.255.255.255/32*/
/* Forward declaratopms */
void rangeToCidr(uint32_t from ,uint32_t to,
void (callback)(char *cidrNotation));
int ipToBin(uint32_t ip , char * pOut);
void printNotation(char *cidrNotation);
/* Globals */
/*******************************************************************************
*
* ipToBin - convert an ipv4 address to binary representation
* and pads zeros to the beginning of the string if
* the length is not 32
* (Important for ranges like 10.10.0.1 - 20.20.20.20 )
*
* ip - ipv4 address on host order
* pOut - Buffer to store binary.
*
* RETURNS: OK or ERROR
*/
int ipToBin(uint32_t ip , char * pOut)
{
char hex[IP_HEX_LENGTH];
int i;
int result=0;
int len;
char pTmp[2];
int tmp;
/*
* XXX: Could use bit operations instead but was easier to debug
*/
char binMap[16][5] = {
"0000","0001","0010","0011", "0100",
"0101","0110","0111","1000", "1001",
"1010","1011","1100", "1101","1110","1111",
};
pTmp[1]=0x0;
memset(hex,0x0,sizeof(hex));
len=sprintf(hex,"%x",ip);
for(i=0;i IP_BINARY_LENGTH-1)
return -1;
/* Success */
return 0;
}
/*******************************************************************************
* main :
*
* arg1 : Start Ip Address
* arg2 : End Ip address
*/
int main (int argc,char **argv)
{
long fromIp, toIp;
struct in_addr addr;
if(argc !=3 )
{
printf("Usage: %s \n",argv[0]);
return(0);
}
/* All operation on host order */
if (inet_aton(argv[1],&addr) == 0)
goto error;
fromIp = ntohl(addr.s_addr);
if (inet_aton(argv[2],&addr) ==0)
goto error;
toIp = ntohl(addr.s_addr);
rangeToCidr(fromIp,toIp,printNotation);
return 0;
error:
printf("Invalid Argument\n");
return -EINVAL;
}
/*******************************************************************************
*
* rangeToCidr - convert an ip Range to CIDR, and call 'callback' to handle
* the value.
*
* from - IP Range start address
* to - IP Range end address
* callback - Callback function to handle cidr.
* RETURNS: OK or ERROR
*/
void rangeToCidr(uint32_t from ,uint32_t to,
void (callback)(char *cidrNotation))
{
int cidrStart = 0;
int cidrEnd = MAX_CIDR_MASK - 1;
long newfrom;
long mask;
char fromIp[IP_BINARY_LENGTH];
char toIp[IP_BINARY_LENGTH];
struct in_addr addr;
char cidrNotation[MAX_CIDR_LEN];
memset (fromIp,0x0,sizeof(fromIp));
memset (toIp,0x0,sizeof(toIp));
if ( ipToBin(from,fromIp) != 0 )
return;
if ( ipToBin(to,toIp) != 0 )
return;
DEBUG ("from %lu to %lu\n", from,to);
DEBUG("from %s\n",fromIp);
DEBUG("to %s\n",toIp);
if(from < to )
{
/* Compare the from and to address ranges to get the first
* point of difference
*/
while(fromIp[cidrStart]==toIp[cidrStart])
cidrStart ++;
cidrStart = 32 - cidrStart -1 ;
DEBUG("cidrStart is %u\n",cidrStart);
/* Starting from the found point of difference make all bits on the
* right side zero
*/
newfrom = from >> cidrStart +1 << cidrStart +1 ;
/* Starting from the end iterate reverse direction to find
* cidrEnd
*/
while( fromIp[cidrEnd] == '0' && toIp[cidrEnd] == '1')
cidrEnd --;
cidrEnd = MAX_CIDR_MASK - 1 - cidrEnd;
DEBUG("cidrEnd is %u\n",cidrEnd);
if(cidrEnd <= cidrStart)
{
/*
* Make all the bit-shifted bits equal to 1, for
* iteration # 1.
*/
mask = pow (2, cidrStart ) - 1;
DEBUG("it1 is %lu \n",newfrom | mask );
rangeToCidr (from , newfrom | mask, callback);
DEBUG("it2 is %lu \n",newfrom | 1 << cidrStart);
rangeToCidr (newfrom | 1 << cidrStart ,to ,callback);
}
else
{
addr.s_addr = htonl(newfrom);
sprintf(cidrNotation,"%s/%d",
inet_ntoa(addr), MAX_CIDR_MASK-cidrEnd);
if (callback != NULL)
callback(cidrNotation);
}
}
else
{
addr.s_addr = htonl(from);
sprintf(cidrNotation,"%s/%d",inet_ntoa(addr),MAX_CIDR_MASK);
if(callback != NULL)
callback(cidrNotation);
}
}
/*******************************************************************************
*
* printNotation - This is an example callback function to handle cidr notation.
*
* RETURNS:
*/
void printNotation(char *cidrNotation)
{
printf("%s\n",cidrNotation);
}
编译：
# gcc rangeToCidr.c -lm -o rang2cidr
Perl版本：
#!/usr/bin/perl -w
# range2cidr.pl
use Net::CIDR;
use Net::CIDR ':all';
if (@ARGV == 0) {
die "Usage Example: $0 192.168.0.0-192.168.255.255 \n";
}
print join("\n", Net::CIDR::range2cidr("$ARGV[0]")) . "\n";
合并CIDR：
#!/usr/bin/perl
use Net::CIDR::Lite;
my $cidr = Net::CIDR::Lite->new;
$cidr->add("202.38.175.0/24");
$cidr->add("202.38.174.0/24");
$cidr->add("202.38.173.0/24");
$cidr->add("202.38.172.0/24");
$cidr->add("202.38.171.0/24");
$cidr->add("202.38.170.0/24");
$cidr->add("202.38.169.0/24");
$cidr->add("202.38.168.0/24");
print "$_\n" for $cidr->list;
// 执行结果：202.38.168.0/21
