1 files changed, 441 insertions, 0 deletions
diff --git a/src/iface.c b/src/iface.c
new file mode 100644
index 0000000..b448cbd
--- /dev/null
+++ b/src/iface.c
@@ -0,0 +1,441 @@
+/*
+  Copyright (c) 2012-2015, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Android port contributor:
+  Copyright (c) 2014-2015, Haofeng "Rick" Lei <ricklei@gmail.com>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+   \file
+
+   Management of the TUN/TAP interface
+*/
+
+#include "fastd.h"
+#include "poll.h"
+
+#include <net/if.h>
+#include <sys/ioctl.h>
+
+#ifdef __linux__
+
+#include <linux/if_tun.h>
+
+#else
+
+#ifndef __APPLE__
+#include <net/if_tun.h>
+#endif
+
+#ifdef __FreeBSD__
+#include <net/if_tap.h>
+#endif
+
+#endif
+
+
+/** Defines if the platform uses an address family header on TUN interfaces */
+#if defined(__linux__) || defined(__APPLE__)
+static const bool multiaf_tun = false;
+#else
+static const bool multiaf_tun = true;
+#endif
+
+#ifdef __linux__
+
+/** Opens the TUN/TAP device helper shared by Android and Linux targets */
+static void open_iface_linux(fastd_iface_t *iface, const char *dev_name) {
+	struct ifreq ifr = {};
+
+	iface->fd = FASTD_POLL_FD(POLL_TYPE_IFACE, open(dev_name, O_RDWR|O_NONBLOCK));
+	if (iface->fd.fd < 0)
+		exit_errno("could not open tun/tap device file");
+
+	if (conf.ifname)
+		strncpy(ifr.ifr_name, conf.ifname, IFNAMSIZ-1);
+
+	switch (conf.mode) {
+	case MODE_TAP:
+		ifr.ifr_flags = IFF_TAP;
+		break;
+
+	case MODE_TUN:
+		ifr.ifr_flags = IFF_TUN;
+		break;
+
+	default:
+		exit_bug("invalid mode");
+	}
+
+	ifr.ifr_flags |= IFF_NO_PI;
+	if (ioctl(iface->fd.fd, TUNSETIFF, &ifr) < 0)
+		exit_errno("TUNSETIFF ioctl failed");
+
+	iface->name = fastd_strndup(ifr.ifr_name, IFNAMSIZ-1);
+
+	int ctl_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (ctl_sock < 0)
+		exit_errno("socket");
+
+	if (ioctl(ctl_sock, SIOCGIFMTU, &ifr) < 0)
+		exit_errno("SIOCGIFMTU ioctl failed");
+
+	if (ifr.ifr_mtu != conf.mtu) {
+		ifr.ifr_mtu = conf.mtu;
+		if (ioctl(ctl_sock, SIOCSIFMTU, &ifr) < 0)
+			exit_errno("SIOCSIFMTU ioctl failed");
+	}
+
+	if (close(ctl_sock))
+		pr_error_errno("close");
+
+}
+
+#endif
+
+#if defined(__ANDROID__)
+
+/** Opens the TUN/TAP device */
+static void open_iface(fastd_iface_t *iface) {
+	if (conf.android_integration) {
+		if (conf.mode != MODE_TUN)
+			exit_error("Non root Android supports only TUN mode");
+
+		pr_debug("using android TUN fd");
+		iface->fd = FASTD_POLL_FD(POLL_TYPE_IFACE, fastd_android_receive_tunfd());
+
+		fastd_android_send_pid();
+	} else {
+		/* this requires root on Android */
+		open_iface_linux(iface, "/dev/tun");
+	}
+}
+
+#elif defined(__linux__)
+
+/** Opens the TUN/TAP device */
+static void open_iface(fastd_iface_t *iface) {
+	open_iface_linux(iface, "/dev/net/tun");
+}
+
+#elif defined(__FreeBSD__) || defined(__OpenBSD__)
+
+/** Sets the MTU of the TUN/TAP device */
+static void set_tun_mtu(fastd_iface_t *iface) {
+	struct tuninfo tuninfo;
+
+	if (ioctl(iface->fd.fd, TUNGIFINFO, &tuninfo) < 0)
+		exit_errno("TUNGIFINFO ioctl failed");
+
+	tuninfo.mtu = conf.mtu;
+
+	if (ioctl(iface->fd.fd, TUNSIFINFO, &tuninfo) < 0)
+		exit_errno("TUNSIFINFO ioctl failed");
+}
+
+
+#ifdef __FreeBSD__
+
+/** Sets the MTU of the TAP device */
+static void set_tap_mtu(fastd_iface_t *iface) {
+	struct tapinfo tapinfo;
+
+	if (ioctl(iface->fd.fd, TAPGIFINFO, &tapinfo) < 0)
+		exit_errno("TAPGIFINFO ioctl failed");
+
+	tapinfo.mtu = conf.mtu;
+
+	if (ioctl(iface->fd.fd, TAPSIFINFO, &tapinfo) < 0)
+		exit_errno("TAPSIFINFO ioctl failed");
+}
+
+/** Sets up the TUN device */
+static void setup_tun(fastd_iface_t *iface) {
+	int one = 1;
+	if (ioctl(iface->fd.fd, TUNSIFHEAD, &one) < 0)
+		exit_errno("TUNSIFHEAD ioctl failed");
+
+	set_tun_mtu(iface);
+}
+
+/** Sets up the TAP device */
+static void setup_tap(fastd_iface_t *iface) {
+	struct ifreq ifr = {};
+
+	if (ioctl(iface->fd.fd, TAPGIFNAME, &ifr) < 0)
+		exit_errno("TAPGIFNAME ioctl failed");
+
+	free(iface->name);
+	iface->name = fastd_strndup(ifr.ifr_name, IFNAMSIZ-1);
+
+	set_tap_mtu(iface);
+}
+
+/** Opens the TUN/TAP device */
+static void open_iface(fastd_iface_t *iface) {
+	char ifname[5+IFNAMSIZ] = "/dev/";
+	const char *type;
+
+	switch (conf.mode) {
+	case MODE_TAP:
+		type = "tap";
+		break;
+
+	case MODE_TUN:
+		type = "tun";
+		break;
+
+	default:
+		exit_bug("invalid mode");
+	}
+
+	if (conf.ifname) {
+		if (strncmp(conf.ifname, type, 3) != 0)
+			exit_error("`%s' doesn't seem to be a %s device", conf.ifname, type);
+
+		strncat(ifname, conf.ifname, IFNAMSIZ-1);
+	}
+	else {
+		strncat(ifname, type, IFNAMSIZ-1);
+	}
+
+	iface->fd = FASTD_POLL_FD(POLL_TYPE_IFACE, open(ifname, O_RDWR|O_NONBLOCK));
+	if (iface->fd.fd < 0)
+		exit_errno("could not open tun/tap device file");
+
+	if (!(iface->name = fdevname_r(iface->fd.fd, fastd_alloc(IFNAMSIZ), IFNAMSIZ)))
+		exit_errno("could not get tun/tap interface name");
+
+	switch (conf.mode) {
+	case MODE_TAP:
+		setup_tap(iface);
+		break;
+
+	case MODE_TUN:
+		setup_tun(iface);
+		break;
+
+	default:
+		exit_bug("invalid mode");
+	}
+}
+
+#else /* __OpenBSD__ */
+
+static void set_link0(fastd_iface_t *iface, bool set) {
+	struct ifreq ifr = {};
+
+	int ctl_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (ctl_sock < 0)
+		exit_errno("socket");
+
+	strncpy(ifr.ifr_name, iface->name, IFNAMSIZ-1);
+	if (ioctl(ctl_sock, SIOCGIFFLAGS, &ifr) < 0)
+		exit_errno("SIOCGIFFLAGS ioctl failed");
+
+	if (set)
+		ifr.ifr_flags |= IFF_LINK0;
+	else
+		ifr.ifr_flags &= ~IFF_LINK0;
+
+	if (ioctl(ctl_sock, SIOCSIFFLAGS, &ifr) < 0)
+		exit_errno("SIOCSIFFLAGS ioctl failed");
+
+	if (close(ctl_sock))
+		pr_error_errno("close");
+}
+
+/** Sets up the TUN device */
+static void setup_tun(fastd_iface_t *iface) {
+	set_link0(iface, false);
+	set_tun_mtu(iface);
+}
+
+/** Sets up the TAP device */
+static void setup_tap(fastd_iface_t *iface) {
+	set_link0(iface, true);
+	set_tun_mtu(iface);
+}
+
+/** Opens the TUN/TAP device */
+static void open_iface(fastd_iface_t *iface) {
+	char ifname[5+IFNAMSIZ] = "/dev/";
+	if (!conf.ifname)
+		exit_error("config error: no interface name given.");
+	else if (strncmp(conf.ifname, "tun", 3) != 0)
+		exit_error("config error: `%s' doesn't seem to be a tun device", conf.ifname);
+	else
+		strncat(ifname, conf.ifname, IFNAMSIZ-1);
+
+	iface->fd = FASTD_POLL_FD(POLL_TYPE_IFACE, open(ifname, O_RDWR|O_NONBLOCK));
+	if (iface->fd.fd < 0)
+		exit_errno("could not open tun device file");
+
+	iface->name = fastd_strndup(conf.ifname, IFNAMSIZ-1);
+
+	switch (conf.mode) {
+	case MODE_TAP:
+		setup_tap(iface);
+		break;
+
+	case MODE_TUN:
+		setup_tun(iface);
+		break;
+
+	default:
+		exit_bug("invalid mode");
+	}
+}
+
+#endif
+
+#elif __APPLE__
+
+/** Opens the TUN/TAP device */
+static void open_iface(fastd_iface_t *iface) {
+	const char *devtype;
+	switch (conf.mode) {
+	case MODE_TAP:
+		devtype = "tap";
+		break;
+
+	case MODE_TUN:
+		devtype = "tun";
+		break;
+
+	default:
+		exit_bug("invalid mode");
+	}
+
+	char ifname[5+IFNAMSIZ] = "/dev/";
+	if (!conf.ifname)
+		exit_error("config error: no interface name given.");
+	else if (strncmp(conf.ifname, devtype, 3) != 0)
+		exit_error("config error: `%s' doesn't seem to be a %s device", conf.ifname, devtype);
+	else
+		strncat(ifname, conf.ifname, IFNAMSIZ-1);
+
+	iface->fd = FASTD_POLL_FD(POLL_TYPE_IFACE, open(ifname, O_RDWR|O_NONBLOCK));
+	if (iface->fd.fd < 0)
+		exit_errno("could not open tun device file");
+
+	iface->name = fastd_strndup(conf.ifname, IFNAMSIZ-1);
+
+	int ctl_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (ctl_sock < 0)
+		exit_errno("socket");
+
+	struct ifreq ifr = {};
+	strncpy(ifr.ifr_name, conf.ifname, IFNAMSIZ-1);
+	ifr.ifr_mtu = conf.mtu;
+	if (ioctl(ctl_sock, SIOCSIFMTU, &ifr) < 0)
+		exit_errno("SIOCSIFMTU ioctl failed");
+
+	if (close(ctl_sock))
+		pr_error_errno("close");
+}
+
+#else
+
+#error unknown tun/tap implementation
+
+#endif
+
+
+/** Reads a packet from the TUN/TAP device */
+void fastd_iface_handle(fastd_iface_t *iface) {
+	size_t max_len = fastd_max_payload();
+
+	fastd_buffer_t buffer;
+	if (multiaf_tun && conf.mode == MODE_TUN)
+		buffer = fastd_buffer_alloc(max_len+4, conf.min_encrypt_head_space+12, conf.min_encrypt_tail_space);
+	else
+		buffer = fastd_buffer_alloc(max_len, conf.min_encrypt_head_space, conf.min_encrypt_tail_space);
+
+	ssize_t len = read(iface->fd.fd, buffer.data, max_len);
+	if (len < 0)
+		exit_errno("read");
+
+	buffer.len = len;
+
+	if (multiaf_tun && conf.mode == MODE_TUN)
+		fastd_buffer_push_head(&buffer, 4);
+
+	fastd_send_data(buffer, iface->peer);
+}
+
+/** Writes a packet to the TUN/TAP device */
+void fastd_iface_write(fastd_iface_t *iface, fastd_buffer_t buffer) {
+	if (multiaf_tun && conf.mode == MODE_TUN) {
+		uint8_t version = *((uint8_t *)buffer.data) >> 4;
+		uint32_t af;
+
+		switch (version) {
+		case 4:
+			af = htonl(AF_INET);
+			break;
+
+		case 6:
+			af = htonl(AF_INET6);
+			break;
+
+		default:
+			pr_warn("fastd_iface_write: unknown IP version %u", version);
+			return;
+		}
+
+		fastd_buffer_pull_head(&buffer, 4);
+		memcpy(buffer.data, &af, 4);
+	}
+
+	if (write(iface->fd.fd, buffer.data, buffer.len) < 0)
+		pr_debug2_errno("write");
+}
+
+fastd_iface_t * fastd_iface_open(fastd_peer_t *peer) {
+	fastd_iface_t *iface = fastd_new(fastd_iface_t);
+	iface->peer = peer;
+
+	pr_debug("initializing tun/tap device...");
+	open_iface(iface);
+
+	if (iface->name)
+		pr_debug("tun/tap device `%s' initialized.", iface->name);
+	else
+		pr_debug("tun/tap device initialized.");
+
+	fastd_poll_fd_register(&iface->fd);
+
+	return iface;
+}
+
+/** Closes the TUN/TAP device */
+void fastd_iface_close(fastd_iface_t *iface) {
+	if (!fastd_poll_fd_close(&iface->fd))
+		pr_warn_errno("closing tun/tap: close");
+
+	free(iface->name);
+	free(iface);
+}