From c5e6cfa708e7e7bec1affd3d7ea71c77c4640a01 Mon Sep 17 00:00:00 2001 From: Bjorn Andersson Date: Mon, 5 Jun 2006 12:41:08 +0000 Subject: [PATCH] initial commit --- Makefile | 21 ++++++++++ dnstun.c | 31 ++++++++++++++ tun.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ tun.h | 28 +++++++++++++ 4 files changed, 203 insertions(+) create mode 100644 Makefile create mode 100644 dnstun.c create mode 100644 tun.c create mode 100644 tun.h diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..6e7f8f5 --- /dev/null +++ b/Makefile @@ -0,0 +1,21 @@ +CC = gcc +OUT = dnstun +OBJS = dnstun.o tun.o + +LDFLAGS = +CFLAGS = -c -g -Wall + +$(OUT): $(OBJS) + $(CC) $(OBJS) -o $(OUT) $(LDFLAGS) + +%.o : %.c %.h + $(CC) $(CFLAGS) $< -o $@ + +clean: + rm -f $(OUT) + rm -f *~ + rm -f *.o + rm -f *.core + +run: $(OUT) + ./$(OUT) diff --git a/dnstun.c b/dnstun.c new file mode 100644 index 0000000..f58f01c --- /dev/null +++ b/dnstun.c @@ -0,0 +1,31 @@ +/* + * Copyright (c) 2006 Bjorn Andersson + * + * 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 "tun.h" + +int +main() +{ + open_tun(); + + sleep(10); + + close_tun(); + + return 0; +} diff --git a/tun.c b/tun.c new file mode 100644 index 0000000..8daa42c --- /dev/null +++ b/tun.c @@ -0,0 +1,123 @@ +/* + * Copyright (c) 2006 Bjorn Andersson + * + * 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" + +#define TUN_MAX_TRY 50 + +int tun_fd = -1; +char *tun_device = NULL; + +#ifdef LINUX + +#include +#include +#include + +int +open_tun() +{ + struct ifreq ifreq; + int i; + + if (tun_device == NULL) + tun_device = "/dev/net/tun"; + + if ((tun_fd = open(tun_device, O_RDWR)) < 0) + err(1, "open_tun: %s: %s", tun_device, strerror(errno)); + + bzero(&ifreq, sizeof(ifreq)); + + ifreq.ifr_flags = IFF_TUN; + + for (i = 0; i < TUN_MAX_TRY; i++) { + snprintf(ifreq.ifr_name, IFNAMSIZ, "tun%d", i); + + if (ioctl(tun_fd, TUNSETIFF, (void *) &ifreq) != -1) { + printf("opened %s\n", ifreq.ifr_name); + return 0; + } + + if (errno != EBUSY) + err(1, "open_tun: ioctl[TUNSETIFF]: %s", strerror(errno)); + } + + err(1, "open_tun: Couldn't set interface name.\n"); + + return 1; +} + +#else /* BSD */ + +int +open_tun() +{ + if (tun_device != NULL) { + if ((tun_fd = open(tun_device, O_RDWR)) < 0) + err(1, "open_tun: %s: %s", tun_device, strerror(errno)); + } else { + char tun_name[50]; + int i; + + for (i = 0; i < TUN_MAX_TRY; i++) { + snprintf(tun_name, sizeof(tun_name), "/dev/tun%d", i); + + if ((tun_fd = open(tun_name, O_RDWR)) >= 0) + return 0; + + if (errno == ENOENT) + break; + } + + err(1, "open_tun: Failed to open tunneling device."); + } + + return 0; +} + +#endif /* LINUX */ + +void +close_tun() +{ + if (tun_fd >= 0) + close(tun_fd); +} + +int +write_tun(u_char *buf, int len) +{ + if (write(tun_fd, buf, len) != len) + err(1, "write_tun: %s", strerror(errno)); + + return 0; +} + +int +read_tun(u_char *buf, int len) +{ + return read(tun_fd, buf, len); +} + diff --git a/tun.h b/tun.h new file mode 100644 index 0000000..baceeca --- /dev/null +++ b/tun.h @@ -0,0 +1,28 @@ +/* + * Copyright (c) 2006 Bjorn Andersson + * + * 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 _TUN_H_ +#define _TUN_H_ + +extern char *tun_device; +extern int tun_fd; + +extern int open_tun(); +extern void close_tun(); +extern int write_tun(u_char *buf, int len); +extern int read_tun(u_char *buf, int len); + +#endif /* _TUN_H_ */