diff --git a/Makefile b/Makefile index d47f9a7..68755b0 100644 --- a/Makefile +++ b/Makefile @@ -1,20 +1,26 @@ CC = gcc -OUT = dnstun -OBJS = dnstun.o tun.o dns.o +DNS = dnstun +DNSOBJS = dnstun.o tun.o dns.o +DNSD = dnstund +DNSDOBJS = dnstund.o tun.o dnsd.o OS = `uname | tr "a-z" "A-Z"` LDFLAGS = CFLAGS = -c -g -Wall -D$(OS) -all: stateos $(OUT) +all: stateos $(DNS) $(DNSD) stateos: @echo OS is $(OS) -$(OUT): $(OBJS) +$(DNS): $(DNSOBJS) @echo LD $@ - @$(CC) $(OBJS) -o $(OUT) $(LDFLAGS) + @$(CC) $(DNSOBJS) -o $(DNS) $(LDFLAGS) + +$(DNSD): $(DNSDOBJS) + @echo LD $@ + @$(CC) $(DNSDOBJS) -o $(DNSD) $(LDFLAGS) .c.o: @echo CC $< @@ -22,7 +28,5 @@ $(OUT): $(OBJS) clean: @echo "Cleaning..." - @rm -f $(OUT) *~ *.o *.core + @rm -f $(DNS) $(DNSD) *~ *.o *.core -run: $(OUT) - ./$(OUT) diff --git a/dnsd.c b/dnsd.c new file mode 100644 index 0000000..deabf82 --- /dev/null +++ b/dnsd.c @@ -0,0 +1,236 @@ +/* + * Copyright (c) 2006 Bjorn Andersson , Erik Ekman + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "dns.h" + +static int host2dns(const char *, char *, int); + +struct sockaddr_in peer; +char topdomain[256]; + +static int +readname(char *packet, char *dst, char *src) +{ + char l; + int len; + int offset; + + len = 0; + + while(*src) { + l = *src++; + len++; + + if(l & 0x80 && l & 0x40) { + offset = ((src[-1] & 0x3f) << 8) | src[0]; + readname(packet, dst, packet + offset); + dst += strlen(dst); + break; + } + + while(l) { + *dst++ = *src++; + l--; + len++; + } + + *dst++ = '.'; + } + + *dst = '\0'; + src++; + len++; + + return len; +} + +#define READNAME(packet, dst, src) (src) += readname((packet), (dst), (src)); + +#define READSHORT(dst, src) \ + (dst) = ntohs(*(short*)(src)); (src)+=2; + +#define READLONG(dst, src) \ + (dst) = ntohl(*(long*)(src)); (src)+=4; + +#define READDATA(dst, src, len) \ + memcpy((dst), (src), (len)); (src)+=(len); + +int +open_dnsd(const char *domain) +{ + int fd; + int flag; + struct sockaddr_in addr; + + bzero(&addr, sizeof(addr)); + addr.sin_family = AF_INET; + addr.sin_port = htons(53); + addr.sin_addr.s_addr = htonl(INADDR_ANY); + + fd = socket(AF_INET, SOCK_DGRAM, 0); + if(fd < 0) { + warn("socket"); + return 0; + } + + flag = 1; +#ifdef SO_REUSEPORT + setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &flag, sizeof(flag)); +#endif + setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag)); + + if(bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) { + warn("bind"); + return 0; + } + + printf("Opened UDP socket\n"); + + return fd; +} + +void +close_dnsd(int fd) +{ + close(fd); +} + +static int +host2dns(const char *host, char *buffer, int size) +{ + char *h; + char *p; + char *word; + + h = strdup(host); + memset(buffer, 0, size); + p = buffer; + + word = strtok(h, "."); + while(word) { + *p++ = (char)strlen(word); + memcpy(p, word, strlen(word)); + p += strlen(word); + + word = strtok(NULL, "."); + } + + *p++ = 0; + + free(h); + + return p - buffer; +} + +static void +dnsd_respond(int fd, struct sockaddr_in from) +{ + int len; + int size; + HEADER *header; + char *p; + char buf[1024]; + + memset(buf, 0, sizeof(buf)); + + len = 0; + header = (HEADER*)buf; + + header->id = 0; + header->qr = 1; + header->opcode = 0; + header->aa = 1; + header->tc = 0; + header->rd = 0; + header->ra = 0; + + header->ancount = htons(1); + + p = buf + sizeof(HEADER); + + p += host2dns("fluff", p, 5); + PUTSHORT(T_PTR, p); + PUTSHORT(C_IN, p); + PUTLONG(htons(3600), p); + + size = host2dns("mupp", p+2, 4); + PUTSHORT(size, p); + p += size; + + len = p - buf; + printf("%d\n", len); + sendto(fd, buf, len, 0, (struct sockaddr*)&from, sizeof(from)); +} + +int +dnsd_read(int fd, char *buf, int buflen) +{ + int i; + int r; + short type; + short class; + short qdcount; + char *data; + char name[255]; + HEADER *header; + socklen_t addrlen; + char packet[64*1024]; + struct sockaddr_in from; + + addrlen = sizeof(struct sockaddr); + r = recvfrom(fd, packet, sizeof(packet), 0, (struct sockaddr*)&from, &addrlen); + + printf("Read %d bytes DNS query from %s\n", r, inet_ntoa(from.sin_addr)); + + if(r == -1) { + perror("recvfrom"); + } else { + header = (HEADER*)packet; + + data = packet + sizeof(HEADER); + + if(!header->qr) { + qdcount = ntohs(header->qdcount); + + for(i=0;i, Erik Ekman + * + * 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. + */ + +#ifndef _DNSD_H_ +#define _DNSD_H_ + +extern struct sockaddr_in peer; + +int open_dnsd(const char *); +void close_dnsd(int); + +int dnsd_read(int, char *, int); + + +#endif /* _DNSD_H_ */ diff --git a/dnstun.c b/dnstun.c index d8ea510..149ade0 100644 --- a/dnstun.c +++ b/dnstun.c @@ -65,7 +65,7 @@ tunnel(int tun_fd, int dns_fd) dns_ping(dns_fd); } else { if(FD_ISSET(tun_fd, &fds)) { - + } if(FD_ISSET(dns_fd, &fds)) { read = dns_read(dns_fd, buf, sizeof(buf)); diff --git a/dnstund.c b/dnstund.c new file mode 100644 index 0000000..0a49d3f --- /dev/null +++ b/dnstund.c @@ -0,0 +1,102 @@ +/* + * Copyright (c) 2006 Bjorn Andersson , Erik Ekman + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +#include "tun.h" +#include "dns.h" +#include "dnsd.h" + +#define MAX(a,b) ((a)>(b)?(a):(b)) + +int running = 1; + +static void +sigint(int sig) { + running = 0; +} + +static int +tunnel(int tun_fd, int dns_fd) +{ + int i; + int read; + fd_set fds; + char buf[1024]; + struct timeval tv; + + while (running) { + tv.tv_sec = 1; + tv.tv_usec = 0; + + FD_ZERO(&fds); + FD_SET(tun_fd, &fds); + FD_SET(dns_fd, &fds); + + i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv); + + if(i < 0) { + if (running) { + warn("select"); + } + return 1; + } + + if(i != 0) { + if(FD_ISSET(tun_fd, &fds)) { + + } + if(FD_ISSET(dns_fd, &fds)) { + read = dnsd_read(dns_fd, buf, sizeof(buf)); + } + } + } + + return 0; +} + +int +main(int argc, char **argv) +{ + int tun_fd; + int dnsd_fd; + + if (argc != 2) { + printf("Usage: %s topdomain\n", argv[0]); + exit(2); + } + + tun_fd = open_tun(); + dnsd_fd = open_dnsd(argv[1]); + + signal(SIGINT, sigint); + + tunnel(tun_fd, dnsd_fd); + + printf("Closing tunnel\n"); + + close_dnsd(dnsd_fd); + close_tun(tun_fd); + + return 0; +}