[icmp-dn.git] / src / idnlookup.c

/*
 *  idnlookup - ICMP Domain Name lookup utility for Linux
 *  Should be installed SUID root, even though I don't know if it's secure yet. :-)
 *  Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com>
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/poll.h>
#include <sys/time.h>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

struct icmphdr {
    u_int8_t type;
    u_int8_t code;
    u_int16_t checksum;
};

struct reqhdr {
    u_int8_t type;
    u_int8_t code;
    u_int16_t checksum;
    u_int16_t id;
    u_int16_t seq;
};

struct rephdr {
    u_int8_t type;
    u_int8_t code;
    u_int16_t checksum;
    u_int16_t id;
    u_int16_t seq;
    int32_t ttl;
    
};

#define ICMP_NAMEREQ 37
#define ICMP_NAMEREP 38

unsigned char buf[65536];

/* DN decompression not yet implemented, since I don't know where to
 * begin counting the offset from -- the beginning of the ICMP
 * payload, or from the beginning of the DN data buffer? */
void printdn(FILE *f, unsigned char *dnbuf, size_t size, int onlyfirst)
{
    unsigned char *p;
    
    p = dnbuf;
    while(p - dnbuf < size) {
	while(*p != 0) {
	    if(*p & 0xc0) {
		fprintf(stderr, "domain name decompression not implemented, aborting\n");
		exit(1);
	    }
	    fprintf(f, "%.*s", (int)*p, p + 1);
	    p += 1 + (int)*p;
	    if(*p != 0)
		fprintf(f, ".");
	}
	p++;
	fprintf(f, "\n");
	if(onlyfirst)
	    break;
    }
}

void cksum(void *hdr, size_t len)
{
    struct icmphdr *ih;
    u_int8_t *cb;
    int i;
    int b1, b2;
    
    ih = (struct icmphdr *)hdr;
    cb = (u_int8_t *)hdr;
    ih->checksum = 0;
    b1 = b2 = 0;
    for(i = 0; i < (len & ~1); i += 2) {
	b1 += cb[i];
	b2 += cb[i + 1];
    }
    if(i & 1)
	b1 += cb[len - 1];
    while(1) {
	if(b1 >= 256) {
	    b2 += b1 >> 8;
	    b1 &= 0xff;
	    continue;
	}
	if(b2 >= 256) {
	    b1 += b2 >> 8;
	    b2 &= 0xff;
	    continue;
	}
	break;
    }
    cb = (u_int8_t *)&ih->checksum;
    cb[0] = ~(u_int8_t)b1;
    cb[1] = ~(u_int8_t)b2;
}

void usage(void)
{
    fprintf(stderr, "usage: idnlookup [-hTa] [-t timeout] host\n");
}

int main(int argc, char **argv)
{
    int ret;
    int s, c;
    int id;
    int namelen;
    struct reqhdr req;
    struct rephdr rep;
    struct iphdr iphdr;
    size_t hdrlen;
    struct addrinfo *ai, *cai, aihint;
    struct pollfd pfd;
    struct timeval tvb, tvc;
    struct sockaddr_storage name;
    int timeout, dispttl, onlyfirst;
    int elapsed, timedout, found;
    
    timeout = 3000;
    dispttl = 0;
    onlyfirst = 1;
    while((c = getopt(argc, argv, "haTt:")) != -1) {
	switch(c) {
	case 't':
	    timeout = atoi(optarg);
	    break;
	case 'a':
	    onlyfirst = 0;
	    break;
	case 'T':
	    dispttl = 1;
	    break;
	case 'h':
	case '?':
	case ':':
	default:
	    usage();
	    exit((c == 'h')?0:1);
	}
    }
    
    if(argc - optind < 1) {
	usage();
	exit(1);
    }
    
    memset(&aihint, 0, sizeof(aihint));
    aihint.ai_socktype = SOCK_RAW;
    aihint.ai_protocol = IPPROTO_ICMP;
    ret = getaddrinfo(argv[optind], NULL, &aihint, &ai);
    
    for(cai = ai; cai != NULL; cai = cai->ai_next) {
	if((s = socket(cai->ai_family, SOCK_RAW, IPPROTO_ICMP)) < 0) {
	    perror("could not create raw socket");
	    exit(1);
	}
	
	id = random() % 65536;
	memset(&req, 0, sizeof(req));
	req.type = ICMP_NAMEREQ;
	req.id = htons(id);
	cksum(&req, sizeof(req));
	
	ret = sendto(s, &req, sizeof(req), 0, cai->ai_addr, cai->ai_addrlen);
	if(ret < 0) {
	    perror("sendto");
	    exit(1);
	} else if(ret != sizeof(req)) {
	    fprintf(stderr, "socket would not send entire packet\n");
	    exit(1);
	}
	
	timedout = 0;
	found = 0;
	gettimeofday(&tvb, NULL);
	while(1) {
	    pfd.fd = s;
	    pfd.events = POLLIN;
	    gettimeofday(&tvc, NULL);
	    elapsed = ((tvc.tv_sec - tvb.tv_sec) * 1000) + ((tvc.tv_usec - tvb.tv_usec) / 1000);
	    if(elapsed >= timeout) {
		timedout = 1;
		break;
	    }
	    ret = poll(&pfd, 1, timeout - elapsed);
	    if(ret < 0) {
		perror("idnlookup: reading data");
		exit(1);
	    }
	    
	    if(pfd.revents & POLLIN) {
		namelen = sizeof(name);
		ret = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&name, &namelen);
		if(ret < 0) {
		    perror("idnlookup: receiving data");
		    exit(1);
		}
		
		if(name.ss_family != cai->ai_addr->sa_family)
		    continue;
		if(name.ss_family == AF_INET) {
		    if(memcmp(&(((struct sockaddr_in *)&name)->sin_addr), &(((struct sockaddr_in *)cai->ai_addr)->sin_addr), sizeof(struct in_addr)))
			continue;
		    if(ret < sizeof(iphdr) + sizeof(rep))
			continue;
		    hdrlen = sizeof(iphdr);
		    memcpy(&iphdr, buf, sizeof(iphdr));
		    if(iphdr.protocol != IPPROTO_ICMP)
			continue;
		} else if(name.ss_family == AF_INET6) {
		    if(memcmp(&(((struct sockaddr_in6 *)&name)->sin6_addr), &(((struct sockaddr_in6 *)cai->ai_addr)->sin6_addr), sizeof(struct in6_addr)))
			continue;
		    if(ret < sizeof(rep))
			continue;
		    hdrlen = 0;
		} else {
		    continue;
		}
		
		memcpy(&rep, buf + hdrlen, sizeof(rep));
		if(rep.type != ICMP_NAMEREP)
		    continue;
		if((ntohs(rep.id) != id) || (ntohs(rep.seq != 0)))
		    continue;
		
		found = 1;
		break;
	    }
	}
	
	close(s);
	
	if(found) {
	    if(dispttl)
		printf("%i\n", ntohl(rep.ttl));
	    printdn(stdout, buf + hdrlen + sizeof(rep), ret - hdrlen - sizeof(rep), onlyfirst);
	    break;
	}
    }
    
    if(timedout) {
	fprintf(stderr, "idnlookup: timeout\n");
	exit(1);
    }
    
    return(0);
}

/*
 * Local Variables:
 * compile-command: "make CFLAGS='-Wall -g'"
 * End:
 */
Commit	Line	Data
3d6143ec DC	1	/*
3d6143ec DC	2	* idnlookup - ICMP Domain Name lookup utility for Linux
ecbdf1d6	3	* Should be installed SUID root, even though I don't know if it's secure yet. :-)
3d6143ec DC	4	* Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*/
51a62941 DC	20	#include <stdlib.h>
	21	#include <unistd.h>
	22	#include <stdio.h>
	23	#include <string.h>
	24	#include <errno.h>
3d6143ec	25	#include <netdb.h>
51a62941 DC	26	#include <sys/socket.h>
51a62941 DC	27	#include <netinet/in.h>
3d6143ec	28	#include <netinet/ip.h>
c9d75321	29	#include <netinet/ip6.h>
51a62941 DC	30	#include <arpa/inet.h>
51a62941 DC	31	#include <sys/types.h>
3d6143ec DC	32	#include <sys/poll.h>
3d6143ec DC	33	#include <sys/time.h>
25415ec8	34	#ifdef HAVE_CONFIG_H
2269406c	35	#include "config.h"
25415ec8	36	#endif
51a62941 DC	37
	38	struct icmphdr {
	39	u_int8_t type;
	40	u_int8_t code;
	41	u_int16_t checksum;
3d6143ec DC	42	};
	43
	44	struct reqhdr {
	45	u_int8_t type;
	46	u_int8_t code;
	47	u_int16_t checksum;
	48	u_int16_t id;
	49	u_int16_t seq;
	50	};
	51
	52	struct rephdr {
	53	u_int8_t type;
	54	u_int8_t code;
	55	u_int16_t checksum;
51a62941 DC	56	u_int16_t id;
51a62941 DC	57	u_int16_t seq;
3d6143ec DC	58	int32_t ttl;
3d6143ec DC	59
51a62941 DC	60	};
	61
	62	#define ICMP_NAMEREQ 37
	63	#define ICMP_NAMEREP 38
	64
3d6143ec DC	65	unsigned char buf[65536];
	66
	67	/* DN decompression not yet implemented, since I don't know where to
	68	* begin counting the offset from -- the beginning of the ICMP
	69	* payload, or from the beginning of the DN data buffer? */
c9d75321	70	void printdn(FILE f, unsigned char dnbuf, size_t size, int onlyfirst)
3d6143ec DC	71	{
	72	unsigned char *p;
	73
	74	p = dnbuf;
	75	while(p - dnbuf < size) {
	76	while(*p != 0) {
	77	if(*p & 0xc0) {
	78	fprintf(stderr, "domain name decompression not implemented, aborting\n");
	79	exit(1);
	80	}
bfd59ca0	81	fprintf(f, "%.s", (int)p, p + 1);
3d6143ec	82	p += 1 + (int)*p;
bfd59ca0 DC	83	if(*p != 0)
bfd59ca0 DC	84	fprintf(f, ".");
3d6143ec DC	85	}
3d6143ec DC	86	p++;
bfd59ca0	87	fprintf(f, "\n");
c9d75321 DC	88	if(onlyfirst)
c9d75321 DC	89	break;
3d6143ec DC	90	}
	91	}
	92
	93	void cksum(void *hdr, size_t len)
	94	{
	95	struct icmphdr *ih;
	96	u_int8_t *cb;
	97	int i;
9cc7607e	98	int b1, b2;
3d6143ec DC	99
	100	ih = (struct icmphdr *)hdr;
	101	cb = (u_int8_t *)hdr;
	102	ih->checksum = 0;
	103	b1 = b2 = 0;
	104	for(i = 0; i < (len & ~1); i += 2) {
	105	b1 += cb[i];
	106	b2 += cb[i + 1];
	107	}
	108	if(i & 1)
	109	b1 += cb[len - 1];
9cc7607e DC	110	while(1) {
	111	if(b1 >= 256) {
	112	b2 += b1 >> 8;
	113	b1 &= 0xff;
	114	continue;
	115	}
	116	if(b2 >= 256) {
	117	b1 += b2 >> 8;
	118	b2 &= 0xff;
	119	continue;
	120	}
	121	break;
	122	}
3d6143ec	123	cb = (u_int8_t *)&ih->checksum;
9cc7607e DC	124	cb[0] = ~(u_int8_t)b1;
9cc7607e DC	125	cb[1] = ~(u_int8_t)b2;
3d6143ec DC	126	}
	127
	128	void usage(void)
	129	{
c9d75321	130	fprintf(stderr, "usage: idnlookup [-hTa] [-t timeout] host\n");
3d6143ec DC	131	}
3d6143ec DC	132
51a62941 DC	133	int main(int argc, char **argv)
	134	{
	135	int ret;
3d6143ec DC	136	int s, c;
	137	int id;
	138	int namelen;
	139	struct reqhdr req;
	140	struct rephdr rep;
	141	struct iphdr iphdr;
c9d75321	142	size_t hdrlen;
3d6143ec DC	143	struct addrinfo ai, cai, aihint;
	144	struct pollfd pfd;
	145	struct timeval tvb, tvc;
	146	struct sockaddr_storage name;
c9d75321 DC	147	int timeout, dispttl, onlyfirst;
c9d75321 DC	148	int elapsed, timedout, found;
51a62941	149
3d6143ec	150	timeout = 3000;
e172b003	151	dispttl = 0;
c9d75321 DC	152	onlyfirst = 1;
c9d75321 DC	153	while((c = getopt(argc, argv, "haTt:")) != -1) {
3d6143ec DC	154	switch(c) {
	155	case 't':
	156	timeout = atoi(optarg);
	157	break;
c9d75321 DC	158	case 'a':
	159	onlyfirst = 0;
	160	break;
e172b003 DC	161	case 'T':
	162	dispttl = 1;
	163	break;
3d6143ec DC	164	case 'h':
	165	case '?':
	166	case ':':
	167	default:
	168	usage();
	169	exit((c == 'h')?0:1);
	170	}
51a62941 DC	171	}
51a62941 DC	172
3d6143ec DC	173	if(argc - optind < 1) {
	174	usage();
	175	exit(1);
	176	}
51a62941	177
3d6143ec	178	memset(&aihint, 0, sizeof(aihint));
3d6143ec DC	179	aihint.ai_socktype = SOCK_RAW;
	180	aihint.ai_protocol = IPPROTO_ICMP;
	181	ret = getaddrinfo(argv[optind], NULL, &aihint, &ai);
51a62941	182
3d6143ec DC	183	for(cai = ai; cai != NULL; cai = cai->ai_next) {
	184	if((s = socket(cai->ai_family, SOCK_RAW, IPPROTO_ICMP)) < 0) {
	185	perror("could not create raw socket");
	186	exit(1);
	187	}
	188
	189	id = random() % 65536;
	190	memset(&req, 0, sizeof(req));
	191	req.type = ICMP_NAMEREQ;
	192	req.id = htons(id);
	193	cksum(&req, sizeof(req));
	194
	195	ret = sendto(s, &req, sizeof(req), 0, cai->ai_addr, cai->ai_addrlen);
	196	if(ret < 0) {
	197	perror("sendto");
	198	exit(1);
	199	} else if(ret != sizeof(req)) {
	200	fprintf(stderr, "socket would not send entire packet\n");
	201	exit(1);
	202	}
	203
c9d75321 DC	204	timedout = 0;
c9d75321 DC	205	found = 0;
3d6143ec DC	206	gettimeofday(&tvb, NULL);
	207	while(1) {
	208	pfd.fd = s;
	209	pfd.events = POLLIN;
	210	gettimeofday(&tvc, NULL);
	211	elapsed = ((tvc.tv_sec - tvb.tv_sec) * 1000) + ((tvc.tv_usec - tvb.tv_usec) / 1000);
899ad19e	212	if(elapsed >= timeout) {
c9d75321 DC	213	timedout = 1;
c9d75321 DC	214	break;
3d6143ec DC	215	}
	216	ret = poll(&pfd, 1, timeout - elapsed);
	217	if(ret < 0) {
	218	perror("idnlookup: reading data");
	219	exit(1);
	220	}
	221
	222	if(pfd.revents & POLLIN) {
	223	namelen = sizeof(name);
	224	ret = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&name, &namelen);
	225	if(ret < 0) {
	226	perror("idnlookup: receiving data");
	227	exit(1);
	228	}
	229
	230	if(name.ss_family != cai->ai_addr->sa_family)
	231	continue;
	232	if(name.ss_family == AF_INET) {
	233	if(memcmp(&(((struct sockaddr_in )&name)->sin_addr), &(((struct sockaddr_in )cai->ai_addr)->sin_addr), sizeof(struct in_addr)))
	234	continue;
c9d75321 DC	235	if(ret < sizeof(iphdr) + sizeof(rep))
	236	continue;
	237	hdrlen = sizeof(iphdr);
	238	memcpy(&iphdr, buf, sizeof(iphdr));
	239	if(iphdr.protocol != IPPROTO_ICMP)
	240	continue;
3d6143ec DC	241	} else if(name.ss_family == AF_INET6) {
	242	if(memcmp(&(((struct sockaddr_in6 )&name)->sin6_addr), &(((struct sockaddr_in6 )cai->ai_addr)->sin6_addr), sizeof(struct in6_addr)))
	243	continue;
c9d75321 DC	244	if(ret < sizeof(rep))
	245	continue;
	246	hdrlen = 0;
3d6143ec DC	247	} else {
	248	continue;
	249	}
	250
c9d75321	251	memcpy(&rep, buf + hdrlen, sizeof(rep));
3d6143ec DC	252	if(rep.type != ICMP_NAMEREP)
	253	continue;
	254	if((ntohs(rep.id) != id) \|\| (ntohs(rep.seq != 0)))
	255	continue;
	256
c9d75321	257	found = 1;
3d6143ec DC	258	break;
	259	}
	260	}
	261
3d6143ec	262	close(s);
c9d75321 DC	263
	264	if(found) {
	265	if(dispttl)
	266	printf("%i\n", ntohl(rep.ttl));
	267	printdn(stdout, buf + hdrlen + sizeof(rep), ret - hdrlen - sizeof(rep), onlyfirst);
	268	break;
	269	}
	270	}
	271
	272	if(timedout) {
	273	fprintf(stderr, "idnlookup: timeout\n");
	274	exit(1);
51a62941	275	}
3d6143ec	276
51a62941 DC	277	return(0);
51a62941 DC	278	}
ecbdf1d6 DC	279
	280	/*
	281	* Local Variables:
9155cd45	282	* compile-command: "make CFLAGS='-Wall -g'"
ecbdf1d6 DC	283	* End:
ecbdf1d6 DC	284	*/