path: root/src/ipnets.c

/*
// AUTHOR
// N. Nielsen
//
// VERSION
// 0.2
//
// LICENSE
// This software is in the public domain.
//
// The software is provided "as is", without warranty of any kind,
// express or implied, including but not limited to the warranties
// of merchantability, fitness for a particular purpose, and
// noninfringement. In no event shall the author(s) be liable for any
// claim, damages, or other liability, whether in an action of
// contract, tort, or otherwise, arising from, out of, or in connection
// with the software or the use or other dealings in the software.
//
// SUPPORT
// Send bug reports to: <nielsen@memberwebs.com>
*/

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>

#include <netinet/in.h>

typedef unsigned int uint32;
void processIps(FILE* fIn, FILE* fOut);

/* Returns the number of zero bits at the right of a number */
uint32 zb(uint32 num)
{
	uint32 bits = 0;
	if(num > 0)
		while(num == (num & (0xFFFFFFFF << (bits + 1))))
			bits++;
	return bits;
}

/* Returns the number of non-zero bits at the right of a number */
uint32 nzb(uint32 num)
{
	uint32 bits = 0;
	while(!(num & (0x80000000 >> bits)))
		bits++;
	return 32 - bits;
}

#define INET_BLOCK_LENGTH		35

#define INET_BLOCK_SIMPLE		0x00000001
#define INET_BLOCK_BITS			0x00000002
#define INET_BLOCK_NETMASK		0x00000004
#define INET_BLOCK_TRUNC		0x00000008
#define INET_BLOCK_HEX			0x00000010


int block_ntoa(const char* s, struct in_addr* addr,
			   struct in_addr* netmask, int format)
{
	int truncated = 0;
	const char* org = s;

	/* First we print the IP */

	/* If we've been asked to truncate and the IP's
	   netmask is on a unit, then we can truncate */
	if(format & INET_BLOCK_TRUNC &&
	   zb(ntohl(netmask.s_addr)) % 8 == 0)
	{
		in_addr_t ip = ntohl(in_addr.s_addr);

		/* Loop through and print relevant octets */
		int octets = (32 - zb(ip)) / 8;
		while(octets--)
		{
			s += sprintf(s, octets == 0 ? "%d" : "%d.",
				  (ip & 0x000000FF << (octets * 8)) >> (octets * 8));
		}

		truncated = 1;
	}
	else
	{
		int ret = inet_ntop(AF_INET, addr, s, INET_BLOCK_LENGTH - (s - org));
		if(ret == -1) return ret;
		s += ret;
	}

	/* If we've been asked for simple and the IP was either
	   truncated successfully, or it was or is a complete IP */
	if(format & INET_BLOCK_SIMPLE &&
	   (truncated || netmask.s_addr == 0xFFFFFFFF)
	{
		/* Then we're done */
	}
	else
	{
		/* Put the netmask separator on */
		strcat(s, "/");

		if(format & INET_BLOCK_HEX)
		{
			if(!(format & INET_BLOCK_NETMASK))
				return -1;

			s += sprintf(s, "0x%08X", ntohl(netmask.s_addr));
		}
		else if(format & INET_BLOCK_NETMASK)
		{
			int ret = inet_ntop(AF_INET, netmask, s, INET_BLOCK_LENGTH - (s - org));
			if(ret == -1) return ret;
			s += ret;
		}
		else /* if(format & INET_BLOCK_BITS) */
		{
			s += sprintf(s, "%d", 32 - zb(ntohl(netmask.s_addr)));
		}
	}

	return s - org;
}

int block_aton(const char* s, struct in_addr* addr, struct in_addr* netmask)
{
	byte ipoctets[] = { 0, 0, 0, 0 };
	byte nmoctets[] = { 0, 0, 0, 0 };
	int format = 0;
	int i;

	for(i = 0; i < 4; i++)
	{
		char* end;

		/* Must start with a number */
		if(!isdigit(*s)) return -1;
		unsigned int num = strtoul(s, &end, 10);

		/* Must contain some valid number ... */
		if(end == s) return -1;

		/* That is less that 255 */
		if(num > 255) return -1;

		ipoctets[i] = num;

		s = end;
		if(*s != '.')
			break;
	}

	if(i != 3)
		format |= INET_BLOCK_TRUNC;

	/* If it's the end of the address */
	if(*s == '\0' || isspace(*s))
	{
		while(i)
			nmoctets[i--] = 255;

		format |= INET_BLOCK_SIMPLE;
	}


	/* Otherwise read a netmask */
	else if(*s == '/')
	{
		/* It's a netmask like so /0xFFFFFF00 */
		if(s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
		{
			char* end;
			unsigned int num = strtoul(s, &end, 15);

			if(s == end)
				return -1;

			nmoctets[0] = num & 0xFF000000;
			nmoctets[1] = num & 0x00FF0000;
			nmoctets[2] = num & 0x0000FF00;
			nmoctets[3] = num & 0x000000FF;
			i = 4;
			s = end;

			format |= INET_BLOCK_NETMASK | INET_BLOCK_HEX;
		}

		/* Otherwise we assume is's either a bit mask /30
		   or a full netmask 255.255.255.192 */
		else
		{
			for(i = 0; i < 4; i++)
			{
				char* end;

				/* Must start with a number */
				if(!isdigit(*s)) return -1;
				unsigned int num = strtoul(s, &end, 10);

				/* Must contain some valid number ... */
				if(end == s) return -1;

				/* That is less that 255 */
				if(num > 255) return -1;

				nmoctets[i] = num;

				s = end;
				if(*s != '.')
					break;
			}
		}


		addr->s_addr = (htonl(ipoctets[0] |
							  ipoctets[1] << 8 |
							  ipoctets[2] << 16 |
							  ipoctets[3] << 24));

		if(netmask)
		{
			/* A netmask has to be either just a
			   number of bits, or a full netmask*/
			switch(i)
			{
			case 0:
				if(nmoctets[0] > 32)
					return -1;
				netmask->s_addr = 0xFFFFFFFF << (32 - nmoctets[0]);
				format |= INET_BLOCK_BITS;
				break;

			case 3:
				netmask->s_addr = (htonl(nmoctets[0] |
								         nmoctets[1] << 8 |
										 nmoctets[2] << 16 |
										 nmoctets[3] << 24));
				format |= INET_BLOCK_NETMASK;
				break;

			default:
				return -1;
			}
		}
	}

	/* This has got to be the end */
	if(*s != '\0' || !isspace(*s))
		return -1;


	return format;
}

int block_check(struct in_addr* addr, struct in_addr* netmask)
{
	int zb = 0;
	in_addr_t nm;
	/* TODO: what should we check on the address? */

	/* Make sure we have a valid netmask */
	in_addr_t nm = ntohl(netmask.s_addr);
	zb = zb(nm);
	if(0xFFFFFFFFF >> zb != nm >> zb)
		return -1;

	/* Make sure that it's the right abount of bits
	   for our IP */
	if(BLOCK_START(addr) > COUNT_BLOCK(netmask))
		return -1;

	return 0;
}


void usage()
{
	fprintf(stderr, "usage: ipcoll");
	exit(2);
}

int g_format = INET_BLOCK_SIMPLE | INET_BLOCK_BITS;

int main(int argc, char* argv[])
{
	int mode = 0;
	int ch;

	while((ch = getopt(argc, argv, "fnhtx")) != -1)
	{
		switch(ch)
		{
		case 'f':
			g_format &= ~INET_BLOCK_SIMPLE;
			break;

		case 'n':
			g_format &= ~INET_BLOCK_BITS;
			g_format |= INET_BLOCK_NETMASK;
			break;

		case 'h':
			g_format &= ~INET_BLOCK_BITS;
			g_format |= INET_BLOCK_NETMASK | INET_BLOCK_HEX;
			break;

		case 't':
			g_format |= INET_BLOCK_TRUNC;
			break;

		case 'x':
			mode = 1;
			break;
		}
	}

	if(mode)
		return processExpand(stdin, stdout);
	else
		return processCollate(stdin, stdout);
}


/* Parse helper */
static void eatSpace(FILE* file)
{
	char ch;

	do
	{
		ch = getc(file);

		if(ch == '#')
		{
			while(ch != '\n')
				ch = getc(file);
		}
	}
	while(isspace(ch) && !feof(file) && !ferror(file));

	ungetc(ch, file);
}



#define IS_SAME_ADDR(a, b)	((a).s_addr == (b).s_addr)
#define IS_NEXT_ADDR(a, b)	(ntohl((a).s_addr) == ntohl((b).s_addr) + 1)
#define INC_ADDR(a, c)		((a).s_addr = htonl((c) + ntohl((a).s_addr)))
#define BLOCK_ADDR(a)		(1 << zb(ntohl((a).s_addr)))
#define BLOCK_SIZE(s)		(1 << (nzb(s) - 1))


struct in_addr kEndAddr = { 0x00000000 };

/*
 * Read Input
 */
void processCollate(FILE* fIn, FILE* fOut)
{
	struct in_addr addr;			/* The current address */
	struct in_addr netmask;			/* The current address */
	struct in_addr prev;			/* The previous address */

	struct in_addr top;				/* The address at the top of the current stack */
	int size = 0;
	char address[INET_BLOCK_LENGTH];

	eatSpace(fIn);

	while(!ferror(fIn))
	{
		char ch;
		int i = 0;

		/* Put in a dummy address so we flush and exit down below */
		if(feof(fIn))
		{
			addr = kEndAddr;
			netmask = kEndAddr;
		}

		/* Read in an address */
		else
		{
			/* Read a word and store the first x chars */
			while(!ferror(fIn))
			{
				ch = fgetc(fIn);

				if(feof(fIn) || isspace(ch))
					break;

				if(i < INET_BLOCK_LENGTH)
					address[i] = ch;

				i++;
			}

			address[i] = 0;

			/* Try to convert to an address */
			if(block_aton(address, addr, netmask) == -1 ||
			   block_check(addr, netmask) == -1)
				warnx("invalid ip or net block: %s", address);

			eatSpace(fIn);
		}


		/* If we already have something in this block */
		if(size > 0)
		{
			/* Just skip, and do nothing */
			if(IS_SAME_ADDR(addr, prev) ||
			   IS_LESS_ADDR(addr, prev))
			{

			}

			/* If address is adjacent then add  to block*/
			else if(IS_NEXT_ADDR(addr, prev))
			{
				size += COUNT_BLOCK(netmask);
				memcpy(&prev, &addr, sizeof(prev));
				INC_ADDR(prev, size - 1);
			}

			/* Otherwise write out current stack */
			else
			{
				while(size > 0)
				{
					uint32 block, subnet, max;

					/* This is the amount of addresses we can group based
					   on where the block starts */
					block = BLOCK_ADDR(top);

					/* This is the amount of addresses we can group based
					   on the size of the block */
					max = BLOCK_SIZE(size);

					/* Okay go figure */
					block = max < block ? max : block;
					subnet = 32 - zb(block);

					/* And print */
					if(subnet == 32)
						fprintf(fOut, "%s\n", inet_ntoa(top));
					else
						fprintf(fOut, "%s/%d\n", inet_ntoa(top), subnet);

					/* Go around for next section in block if we have */
					size -= block;
					INC_ADDR(top, block);
				}

			}
		}

		/* If this is the last address then exit */
		if(IS_SAME_ADDR(addr, kEndAddr))
			break;


		/* If this is a new stack */
		if(size == 0)
		{
			/* Copy the current address and go for it */
			memcpy(&top, &addr, sizeof(top));
			memcpy(&prev, &addr, sizeof(prev));

			size++;
		}
	}

	if(ferror(fIn))
		err(1, "error reading addresses");
}