X-Git-Url: http://dolda2000.com/gitweb/?a=blobdiff_plain;f=src%2Fidnlookup.c;fp=src%2Fidnlookup.c;h=e97f62fd51360fca9a19e3955825605833bae081;hb=21c92d5d484277cf22f62ecc8e60db1608e062ad;hp=0000000000000000000000000000000000000000;hpb=bbb05b86699cdb941ecbd93e38654e4199d0a150;p=icmp-dn.git diff --git a/src/idnlookup.c b/src/idnlookup.c new file mode 100644 index 0000000..e97f62f --- /dev/null +++ b/src/idnlookup.c @@ -0,0 +1,281 @@ +/* + * 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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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: + */