[icmp-dn.git] / 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>

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: "gcc -Wall -g -o idnlookup idnlookup.c"
 * 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>
51a62941 DC	34
	35	struct icmphdr {
	36	u_int8_t type;
	37	u_int8_t code;
	38	u_int16_t checksum;
3d6143ec DC	39	};
	40
	41	struct reqhdr {
	42	u_int8_t type;
	43	u_int8_t code;
	44	u_int16_t checksum;
	45	u_int16_t id;
	46	u_int16_t seq;
	47	};
	48
	49	struct rephdr {
	50	u_int8_t type;
	51	u_int8_t code;
	52	u_int16_t checksum;
51a62941 DC	53	u_int16_t id;
51a62941 DC	54	u_int16_t seq;
3d6143ec DC	55	int32_t ttl;
3d6143ec DC	56
51a62941 DC	57	};
	58
	59	#define ICMP_NAMEREQ 37
	60	#define ICMP_NAMEREP 38
	61
3d6143ec DC	62	unsigned char buf[65536];
	63
	64	/* DN decompression not yet implemented, since I don't know where to
	65	* begin counting the offset from -- the beginning of the ICMP
	66	* payload, or from the beginning of the DN data buffer? */
c9d75321	67	void printdn(FILE f, unsigned char dnbuf, size_t size, int onlyfirst)
3d6143ec DC	68	{
	69	unsigned char *p;
	70
	71	p = dnbuf;
	72	while(p - dnbuf < size) {
	73	while(*p != 0) {
	74	if(*p & 0xc0) {
	75	fprintf(stderr, "domain name decompression not implemented, aborting\n");
	76	exit(1);
	77	}
bfd59ca0	78	fprintf(f, "%.s", (int)p, p + 1);
3d6143ec	79	p += 1 + (int)*p;
bfd59ca0 DC	80	if(*p != 0)
bfd59ca0 DC	81	fprintf(f, ".");
3d6143ec DC	82	}
3d6143ec DC	83	p++;
bfd59ca0	84	fprintf(f, "\n");
c9d75321 DC	85	if(onlyfirst)
c9d75321 DC	86	break;
3d6143ec DC	87	}
	88	}
	89
	90	void cksum(void *hdr, size_t len)
	91	{
	92	struct icmphdr *ih;
	93	u_int8_t *cb;
	94	int i;
9cc7607e	95	int b1, b2;
3d6143ec DC	96
	97	ih = (struct icmphdr *)hdr;
	98	cb = (u_int8_t *)hdr;
	99	ih->checksum = 0;
	100	b1 = b2 = 0;
	101	for(i = 0; i < (len & ~1); i += 2) {
	102	b1 += cb[i];
	103	b2 += cb[i + 1];
	104	}
	105	if(i & 1)
	106	b1 += cb[len - 1];
9cc7607e DC	107	while(1) {
	108	if(b1 >= 256) {
	109	b2 += b1 >> 8;
	110	b1 &= 0xff;
	111	continue;
	112	}
	113	if(b2 >= 256) {
	114	b1 += b2 >> 8;
	115	b2 &= 0xff;
	116	continue;
	117	}
	118	break;
	119	}
3d6143ec	120	cb = (u_int8_t *)&ih->checksum;
9cc7607e DC	121	cb[0] = ~(u_int8_t)b1;
9cc7607e DC	122	cb[1] = ~(u_int8_t)b2;
3d6143ec DC	123	}
	124
	125	void usage(void)
	126	{
c9d75321	127	fprintf(stderr, "usage: idnlookup [-hTa] [-t timeout] host\n");
3d6143ec DC	128	}
3d6143ec DC	129
51a62941 DC	130	int main(int argc, char **argv)
	131	{
	132	int ret;
3d6143ec DC	133	int s, c;
	134	int id;
	135	int namelen;
	136	struct reqhdr req;
	137	struct rephdr rep;
	138	struct iphdr iphdr;
c9d75321	139	size_t hdrlen;
3d6143ec DC	140	struct addrinfo ai, cai, aihint;
	141	struct pollfd pfd;
	142	struct timeval tvb, tvc;
	143	struct sockaddr_storage name;
c9d75321 DC	144	int timeout, dispttl, onlyfirst;
c9d75321 DC	145	int elapsed, timedout, found;
51a62941	146
3d6143ec	147	timeout = 3000;
e172b003	148	dispttl = 0;
c9d75321 DC	149	onlyfirst = 1;
c9d75321 DC	150	while((c = getopt(argc, argv, "haTt:")) != -1) {
3d6143ec DC	151	switch(c) {
	152	case 't':
	153	timeout = atoi(optarg);
	154	break;
c9d75321 DC	155	case 'a':
	156	onlyfirst = 0;
	157	break;
e172b003 DC	158	case 'T':
	159	dispttl = 1;
	160	break;
3d6143ec DC	161	case 'h':
	162	case '?':
	163	case ':':
	164	default:
	165	usage();
	166	exit((c == 'h')?0:1);
	167	}
51a62941 DC	168	}
51a62941 DC	169
3d6143ec DC	170	if(argc - optind < 1) {
	171	usage();
	172	exit(1);
	173	}
51a62941	174
3d6143ec	175	memset(&aihint, 0, sizeof(aihint));
3d6143ec DC	176	aihint.ai_socktype = SOCK_RAW;
	177	aihint.ai_protocol = IPPROTO_ICMP;
	178	ret = getaddrinfo(argv[optind], NULL, &aihint, &ai);
51a62941	179
3d6143ec DC	180	for(cai = ai; cai != NULL; cai = cai->ai_next) {
	181	if((s = socket(cai->ai_family, SOCK_RAW, IPPROTO_ICMP)) < 0) {
	182	perror("could not create raw socket");
	183	exit(1);
	184	}
	185
	186	id = random() % 65536;
	187	memset(&req, 0, sizeof(req));
	188	req.type = ICMP_NAMEREQ;
	189	req.id = htons(id);
	190	cksum(&req, sizeof(req));
	191
	192	ret = sendto(s, &req, sizeof(req), 0, cai->ai_addr, cai->ai_addrlen);
	193	if(ret < 0) {
	194	perror("sendto");
	195	exit(1);
	196	} else if(ret != sizeof(req)) {
	197	fprintf(stderr, "socket would not send entire packet\n");
	198	exit(1);
	199	}
	200
c9d75321 DC	201	timedout = 0;
c9d75321 DC	202	found = 0;
3d6143ec DC	203	gettimeofday(&tvb, NULL);
	204	while(1) {
	205	pfd.fd = s;
	206	pfd.events = POLLIN;
	207	gettimeofday(&tvc, NULL);
	208	elapsed = ((tvc.tv_sec - tvb.tv_sec) * 1000) + ((tvc.tv_usec - tvb.tv_usec) / 1000);
899ad19e	209	if(elapsed >= timeout) {
c9d75321 DC	210	timedout = 1;
c9d75321 DC	211	break;
3d6143ec DC	212	}
	213	ret = poll(&pfd, 1, timeout - elapsed);
	214	if(ret < 0) {
	215	perror("idnlookup: reading data");
	216	exit(1);
	217	}
	218
	219	if(pfd.revents & POLLIN) {
	220	namelen = sizeof(name);
	221	ret = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&name, &namelen);
	222	if(ret < 0) {
	223	perror("idnlookup: receiving data");
	224	exit(1);
	225	}
	226
	227	if(name.ss_family != cai->ai_addr->sa_family)
	228	continue;
	229	if(name.ss_family == AF_INET) {
	230	if(memcmp(&(((struct sockaddr_in )&name)->sin_addr), &(((struct sockaddr_in )cai->ai_addr)->sin_addr), sizeof(struct in_addr)))
	231	continue;
c9d75321 DC	232	if(ret < sizeof(iphdr) + sizeof(rep))
	233	continue;
	234	hdrlen = sizeof(iphdr);
	235	memcpy(&iphdr, buf, sizeof(iphdr));
	236	if(iphdr.protocol != IPPROTO_ICMP)
	237	continue;
3d6143ec DC	238	} else if(name.ss_family == AF_INET6) {
	239	if(memcmp(&(((struct sockaddr_in6 )&name)->sin6_addr), &(((struct sockaddr_in6 )cai->ai_addr)->sin6_addr), sizeof(struct in6_addr)))
	240	continue;
c9d75321 DC	241	if(ret < sizeof(rep))
	242	continue;
	243	hdrlen = 0;
3d6143ec DC	244	} else {
	245	continue;
	246	}
	247
c9d75321	248	memcpy(&rep, buf + hdrlen, sizeof(rep));
3d6143ec DC	249	if(rep.type != ICMP_NAMEREP)
	250	continue;
	251	if((ntohs(rep.id) != id) \|\| (ntohs(rep.seq != 0)))
	252	continue;
	253
c9d75321	254	found = 1;
3d6143ec DC	255	break;
	256	}
	257	}
	258
3d6143ec	259	close(s);
c9d75321 DC	260
	261	if(found) {
	262	if(dispttl)
	263	printf("%i\n", ntohl(rep.ttl));
	264	printdn(stdout, buf + hdrlen + sizeof(rep), ret - hdrlen - sizeof(rep), onlyfirst);
	265	break;
	266	}
	267	}
	268
	269	if(timedout) {
	270	fprintf(stderr, "idnlookup: timeout\n");
	271	exit(1);
51a62941	272	}
3d6143ec	273
51a62941 DC	274	return(0);
51a62941 DC	275	}
ecbdf1d6 DC	276
	277	/*
	278	* Local Variables:
	279	* compile-command: "gcc -Wall -g -o idnlookup idnlookup.c"
	280	* End:
	281	*/