iodine/src/dns.c

455 lines
8.6 KiB
C
Raw Normal View History

2006-06-05 16:38:10 +03:00
/*
2006-06-05 17:15:53 +03:00
* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@kryo.se>
2006-06-05 16:38:10 +03:00
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
2006-06-25 02:38:22 +03:00
#ifdef DARWIN
#include <arpa/nameser8_compat.h>
#endif
2006-06-05 17:13:32 +03:00
#include <netdb.h>
2006-06-05 16:38:10 +03:00
#include <time.h>
#include <err.h>
#include <stdio.h>
#include <stdint.h>
2006-06-05 16:38:10 +03:00
#include <stdlib.h>
2006-06-25 00:11:16 +03:00
#include <stdint.h>
2006-06-05 16:38:10 +03:00
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include "dns.h"
2006-08-13 02:24:59 +03:00
#include "encoding.h"
#include "read.h"
2006-06-05 16:38:10 +03:00
2006-08-13 21:58:54 +03:00
// For FreeBSD
#ifndef MIN
#define MIN(a,b) ((a)<(b)?(a):(b))
#endif
2006-06-24 14:33:57 +03:00
2006-06-11 19:13:40 +03:00
static int dns_write(int, int, char *, int, char);
static void dns_query(int, int, char *, int);
2007-01-28 08:47:51 +02:00
static int decodepacket(const char*, char*, int);
2006-06-05 17:37:58 +03:00
2007-01-28 06:30:43 +02:00
static struct sockaddr_in peer;
static char topdomain[256];
2006-06-05 17:13:32 +03:00
2006-06-05 23:05:11 +03:00
// Current IP packet
2007-01-28 06:30:43 +02:00
static char activepacket[4096];
static int lastlen;
static int packetpos;
static int packetlen;
static uint16_t chunkid;
2006-06-05 23:05:11 +03:00
2007-01-28 06:30:43 +02:00
static uint16_t pingid;
2006-06-11 20:23:26 +03:00
void
dns_set_topdomain(const char *domain)
{
strncpy(topdomain, domain, sizeof(topdomain) - 1);
topdomain[sizeof(topdomain) - 1] = '\0';
}
2006-06-11 22:54:23 +03:00
int
dns_settarget(const char *host)
{
struct hostent *h;
2006-06-05 16:38:10 +03:00
// Init dns target struct
h = gethostbyname(host);
if (!h) {
2006-06-11 16:05:41 +03:00
printf("Could not resolve name %s, exiting\n", host);
2006-06-11 17:42:19 +03:00
return -1;
}
2006-06-11 22:54:23 +03:00
2006-11-08 23:45:28 +02:00
memset(&peer, 0, sizeof(peer));
peer.sin_family = AF_INET;
peer.sin_port = htons(53);
peer.sin_addr = *((struct in_addr *) h->h_addr);
2006-06-05 23:05:11 +03:00
// Init chunk id
chunkid = 0;
pingid = 0;
2006-06-05 23:05:11 +03:00
2006-06-11 22:54:23 +03:00
return 0;
2006-06-11 16:13:20 +03:00
}
2006-06-05 17:13:32 +03:00
2006-06-05 23:05:11 +03:00
int
dns_sending()
{
return (packetlen != 0);
}
static void
dns_send_chunk(int fd)
{
int avail;
char *p;
p = activepacket;
p += packetpos;
avail = packetlen - packetpos;
2006-06-06 18:40:06 +03:00
lastlen = dns_write(fd, ++chunkid, p, avail, 0);
2006-06-05 23:05:11 +03:00
}
void
dns_handle_tun(int fd, char *data, int len)
{
memcpy(activepacket, data, MIN(len, sizeof(activepacket)));
lastlen = 0;
packetpos = 0;
packetlen = len;
dns_send_chunk(fd);
}
2006-06-05 17:43:04 +03:00
void
2006-06-05 18:13:30 +03:00
dns_ping(int dns_fd)
2006-06-05 17:43:04 +03:00
{
2006-06-06 20:17:05 +03:00
char data[2];
2006-06-05 23:05:11 +03:00
if (dns_sending()) {
lastlen = 0;
packetpos = 0;
packetlen = 0;
2006-06-05 23:05:11 +03:00
}
2006-06-06 20:17:05 +03:00
data[0] = (pingid & 0xFF00) >> 8;
data[1] = (pingid & 0xFF);
2006-06-11 19:13:40 +03:00
dns_write(dns_fd, ++pingid, data, 2, 'P');
}
2006-11-18 18:08:47 +02:00
void
dns_login(int dns_fd, char *login, int len)
{
char data[18];
memcpy(data, login, MIN(len, 16));
data[16] = (pingid & 0xFF00) >> 8;
data[17] = (pingid & 0xFF);
dns_write(dns_fd, ++pingid, data, 18, 'L');
}
2006-06-11 19:13:40 +03:00
void
2006-11-18 18:08:47 +02:00
dns_send_version(int dns_fd, int version)
2006-06-11 19:13:40 +03:00
{
2006-11-18 18:08:47 +02:00
char data[6];
int v;
v = htonl(version);
memcpy(data, &v, 4);
data[4] = (pingid & 0xFF00) >> 8;
data[5] = (pingid & 0xFF);
dns_write(dns_fd, ++pingid, data, 6, 'V');
2006-06-05 17:43:04 +03:00
}
int
dns_encode(char *buf, size_t buflen, struct query *q, qr_t qr, char *data, size_t datalen)
2006-06-05 17:37:58 +03:00
{
HEADER *header;
short name;
2006-06-05 17:37:58 +03:00
char *p;
int len;
memset(buf, 0, buflen);
2006-06-05 17:37:58 +03:00
header = (HEADER*)buf;
header->id = htons(q->id);
header->qr = qr;
2006-06-05 17:37:58 +03:00
header->opcode = 0;
header->aa = (qr == QR_ANSWER);
2006-06-05 17:37:58 +03:00
header->tc = 0;
header->rd = (qr == QR_QUERY);
2006-06-05 17:37:58 +03:00
header->ra = 0;
p = buf + sizeof(HEADER);
switch (qr) {
case QR_ANSWER:
header->ancount = htons(1);
header->qdcount = htons(1);
name = 0xc000 | ((p - buf) & 0x3fff);
p += dns_encode_hostname(q->name, p, strlen(q->name));
putshort(&p, q->type);
putshort(&p, C_IN);
putshort(&p, name);
putshort(&p, q->type);
putshort(&p, C_IN);
putlong(&p, 0);
/*
* XXX: This is jidder! This is used to detect if there's packets to be sent.
*/
q->id = 0;
putshort(&p, datalen);
putdata(&p, data, datalen);
break;
case QR_QUERY:
header->qdcount = htons(1);
header->arcount = htons(1);
p += dns_encode_hostname(data, p, datalen);
putshort(&p, q->type);
putshort(&p, C_IN);
// EDNS0
putbyte(&p, 0x00); //Root
putshort(&p, 0x0029); // OPT
putshort(&p, 0x1000); // Payload size: 4096
putshort(&p, 0x0000); // Higher bits/edns version
putshort(&p, 0x8000); // Z
putshort(&p, 0x0000); // Data length
break;
default:
errx(1, "dns_encode: qr is wrong!!!");
/* NOTREACHED */
}
len = p - buf;
2006-06-05 17:37:58 +03:00
return len;
}
2006-06-06 16:11:29 +03:00
2007-01-28 08:47:51 +02:00
int
dns_decode(char *buf, size_t buflen, struct query *q, qr_t qr, char *packet, size_t packetlen)
2007-01-28 08:47:51 +02:00
{
char rdata[4*1024];
HEADER *header;
short qdcount;
short ancount;
char name[255];
uint32_t ttl;
short class;
short type;
char *data;
short rlen;
int id;
int rv;
rv = 0;
header = (HEADER*)packet;
// Reject short packets
if (packetlen < sizeof(HEADER)) {
return rv;
}
2007-01-28 08:47:51 +02:00
if (header->qr != qr) {
warnx("header->qr does not match the requested qr");
return -1;
}
2007-01-28 08:47:51 +02:00
data = packet + sizeof(HEADER);
qdcount = ntohs(header->qdcount);
ancount = ntohs(header->ancount);
id = ntohs(header->id);
rlen = 0;
switch (qr) {
case QR_ANSWER:
if(qdcount != 1 || ancount != 1) {
warnx("no query or answer in answer");
return -1;
}
readname(packet, packetlen, &data, name, sizeof(name));
readshort(packet, &data, &type);
readshort(packet, &data, &class);
readname(packet, packetlen, &data, name, sizeof(name));
readshort(packet, &data, &type);
readshort(packet, &data, &class);
readlong(packet, &data, &ttl);
readshort(packet, &data, &rlen);
rv = MIN(rlen, sizeof(rdata));
2007-02-04 19:22:07 +02:00
rv = readdata(packet, &data, rdata, rv);
2007-01-28 08:47:51 +02:00
if(type == T_NULL && rv > 2) {
rv = MIN(rv, buflen);
memcpy(buf, rdata, rv);
}
break;
case QR_QUERY:
if (qdcount != 1) {
warnx("no query on query");
return -1;
}
readname(packet, packetlen, &data, name, sizeof(name) -1);
name[256] = 0;
readshort(packet, &data, &type);
readshort(packet, &data, &class);
2007-02-04 19:22:07 +02:00
if(type != T_NULL) {
rv = 0;
break;
}
2007-01-28 08:47:51 +02:00
strncpy(q->name, name, 257);
q->type = type;
q->id = id;
rv = decodepacket(name, buf, buflen);
break;
}
return rv;
}
static void
dns_query(int fd, int id, char *host, int type)
{
char buf[1024];
struct query q;
int peerlen;
int len;
2006-06-05 17:37:58 +03:00
q.id = id;
q.type = type;
len = dns_encode(buf, sizeof(buf), &q, QR_QUERY, host, strlen(host));
peerlen = sizeof(peer);
2006-06-05 23:05:11 +03:00
sendto(fd, buf, len, 0, (struct sockaddr*)&peer, peerlen);
2006-06-05 17:37:58 +03:00
}
2006-06-11 19:13:40 +03:00
static int
dns_write(int fd, int id, char *buf, int len, char flag)
2006-06-05 21:36:34 +03:00
{
int avail;
2006-08-13 02:24:59 +03:00
int written;
int encoded;
2006-06-05 23:21:49 +03:00
char data[257];
2006-06-05 21:36:34 +03:00
char *d;
avail = 0xFF - strlen(topdomain) - 2;
2006-11-08 23:45:28 +02:00
memset(data, 0, sizeof(data));
2006-06-05 21:36:34 +03:00
d = data;
2006-08-13 02:24:59 +03:00
written = encode_data(buf, len, avail, d, flag);
encoded = strlen(data);
d += encoded;
2006-06-06 02:34:44 +03:00
if (*d != '.') {
*d++ = '.';
}
2006-06-05 23:21:49 +03:00
strncpy(d, topdomain, strlen(topdomain)+1);
2006-06-05 21:36:34 +03:00
2006-06-06 05:07:29 +03:00
dns_query(fd, id, data, T_NULL);
2006-08-13 02:24:59 +03:00
return written;
2006-06-05 21:36:34 +03:00
}
2006-06-05 18:13:30 +03:00
int
2006-06-05 18:36:13 +03:00
dns_read(int fd, char *buf, int buflen)
2006-06-05 18:13:30 +03:00
{
int r;
socklen_t addrlen;
char packet[64*1024];
struct sockaddr_in from;
HEADER *header;
addrlen = sizeof(struct sockaddr);
r = recvfrom(fd, packet, sizeof(packet), 0, (struct sockaddr*)&from, &addrlen);
if(r == -1) {
perror("recvfrom");
return 0;
}
header = (HEADER*)packet;
if (dns_sending() && chunkid == ntohs(header->id)) {
/* Got ACK on sent packet */
packetpos += lastlen;
if (packetpos == packetlen) {
/* Packet completed */
packetpos = 0;
packetlen = 0;
lastlen = 0;
} else {
/* More to send */
dns_send_chunk(fd);
}
}
2007-01-28 08:47:51 +02:00
return dns_decode(buf, buflen, NULL, QR_ANSWER, packet, r);
2006-06-05 18:13:30 +03:00
}
2006-11-05 13:44:43 +02:00
int
dns_encode_hostname(const char *host, char *buffer, int size)
2006-06-05 17:37:58 +03:00
{
char *h;
char *p;
char *word;
2006-11-05 13:44:43 +02:00
int left;
2006-06-05 17:37:58 +03:00
h = strdup(host);
memset(buffer, 0, size);
p = buffer;
2006-11-05 13:44:43 +02:00
left = size;
2006-06-05 17:37:58 +03:00
word = strtok(h, ".");
while(word) {
2006-11-05 13:44:43 +02:00
if (strlen(word) > 63 || strlen(word) > left) {
2007-01-28 04:01:39 +02:00
free(h);
2006-11-05 13:44:43 +02:00
return -1;
}
left -= (strlen(word) + 1);
2006-06-05 17:37:58 +03:00
*p++ = (char)strlen(word);
memcpy(p, word, strlen(word));
p += strlen(word);
word = strtok(NULL, ".");
}
*p++ = 0;
free(h);
return p - buffer;
}
2006-06-11 15:57:29 +03:00
2006-06-11 15:57:29 +03:00
void
dnsd_send(int fd, struct query *q, char *data, int datalen)
2006-06-11 15:57:29 +03:00
{
char buf[64*1024];
int len;
2006-06-11 15:57:29 +03:00
len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, data, datalen);
2006-06-11 15:57:29 +03:00
sendto(fd, buf, len, 0, (struct sockaddr*)&q->from, q->fromlen);
2006-06-11 15:57:29 +03:00
}
static int
2006-06-11 21:07:26 +03:00
decodepacket(const char *name, char *buf, int buflen)
2006-06-11 15:57:29 +03:00
{
int len;
char *domain;
domain = strstr(name, topdomain);
2006-08-13 02:24:59 +03:00
len = decode_data(buf, buflen, name, domain);
2006-06-11 21:07:26 +03:00
if (len == buflen)
return -1;
2006-06-11 15:57:29 +03:00
return len;
}