| /* |
| * |
| * Copyright (c) 2020 Project CHIP Authors |
| * Copyright (c) 2018 Google LLC. |
| * Copyright (c) 2014-2017 Nest Labs, Inc. |
| * Copyright (c) 2001-2003 Swedish Institute of Computer Science. |
| * All rights reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /** |
| * @file |
| * This file implements a TUN/TAP interface shim for LwIP, used |
| * when running LwIP on non-LWIP-native platforms such as BSD |
| * sockets, to interface with host OS network interfaces on such |
| * platforms and the Internet, accessed via those host OS network |
| * interfaces. |
| * |
| * The APIs in this module used by the setup and intialization |
| * code of applications are: |
| * |
| * 1. TapInterface_Init |
| * 2. TapInterface_SetupNetif |
| * 3. TapInterface_Select |
| * |
| * and are generally used in the order listed. |
| * |
| * .------------------------------------------. |
| * | | |
| * .--.------------| Application | |
| * .--------|--|--------. | . . . | |
| * | V V | '------+-----------+-------------+---------' |
| * | | | | | |
| * | LwIP | .------|-----------|-------------+---------. |
| * | | | V V V | |
| * | .----------------. | | .-------. .------------. .---------. | |
| * | | | | | | Init | | SetupNetif | | Select |--. | |
| * | | | | | '-------' '------------' '---------' | | |
| * | | netif | | | | | |
| * | | | | | .-------------. .-------------. | | |
| * | | .------------. | | | | Low Level | | Low Level | | | |
| * | | | linkoutput +-|-+---+----+> Output | | Input <+----| | |
| * | | '------------' | | | | . | | ^ | | | |
| * | | | | | '------+------' '------|------' | | |
| * | | .------------. | | | | | | | |
| * | | | input <+-+-+---+-----------|----------------|-----------' | |
| * | | '------------' | | | | | | |
| * | '----------------' | | .-------|----------------+---------. | |
| * '--------------------' | | V ' | | |
| * | | File Descriptor | | |
| * | | ^ | | |
| * | '----------------|-----------------' | |
| * '--------------------|---------------------' |
| * | |
| * .------------------|-------------------. |
| * | | | |
| * | .--------------|---------------. | |
| * | | .------------|-------------. | | |
| * | | | V | | | |
| * | | | TUN/TAP Shim Interface | | | |
| * | | | | | | |
| * | | '--------------------------' | | |
| * | | | | |
| * | | TUN/TAP Driver | | |
| * | | | | |
| * | '------------------------------' | |
| * | | |
| * | Host OS | |
| * | | |
| * '--------------------------------------' |
| * |
| * This file was originally adapted from 'contrib/ports/unix/port/ |
| * netif/tapif.c' in the LwIP distribution. |
| * |
| */ |
| |
| /*-----------------------------------------------------------------------------------*/ |
| /* |
| * Copyright (c) 2001-2003 Swedish Institute of Computer Science. |
| * 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. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. |
| * |
| * This file is part of the lwIP TCP/IP stack. |
| * |
| * Author: Adam Dunkels <adam@sics.se> |
| * |
| */ |
| |
| #include "TapInterface.h" |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <netinet/in.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/ioctl.h> |
| #include <sys/socket.h> |
| #include <sys/time.h> |
| #include <sys/types.h> |
| #include <sys/uio.h> |
| #include <unistd.h> |
| |
| #if defined(linux) |
| #include <linux/if.h> |
| #include <linux/if_tun.h> |
| #include <sys/ioctl.h> |
| #define DEVTAP "/dev/net/tun" |
| |
| #elif defined(openbsd) |
| #define DEVTAP "/dev/tun0" |
| |
| #else /* freebsd, cygwin? */ |
| #include <net/if.h> |
| #define DEVTAP "/dev/tap0" |
| #endif |
| |
| #include <lwip/ethip6.h> |
| #include <lwip/mem.h> |
| #include <lwip/snmp.h> |
| #include <lwip/stats.h> |
| #include <netif/etharp.h> |
| |
| /* Global Variables */ |
| |
| static const size_t kMacLength = sizeof(((TapInterface *) (0))->macAddr); |
| |
| /** |
| * This is the LwIP TUN/TAP shim interface low level output method. |
| * |
| * When the native LwIP stack has output for its native interface, \c |
| * netif, associated with the LwIP TUN/TAP shim interface, LwIP |
| * invokes this method to drive the specified buffer to the shim |
| * interface. |
| * |
| * @param[in] netif A pointer to the LwIP native interface |
| * associated with the TUN/TAP shim interface |
| * onto which the output should be driven. |
| * |
| * @param[in] buf A pointer to the packet buffer containing the |
| * output to drive onto the shim interface. |
| * |
| * @retval #ERR_OK on successfully driving the buffer onto the |
| * shim interface. |
| * |
| * @retval #ERR_MEM if an encapsulation buffer cannot be allocated. |
| * |
| * @retval #ERR_BUF if the allocated encapsulation buffer is not big |
| * enough to encapsulate the output data. |
| * |
| * @retval #ERR_IF if the output data cannot be driven onto the shim |
| * interface. |
| * |
| * @sa #TapInterface_SetupNetif |
| * |
| */ |
| static err_t TapInterface_low_level_output(struct netif * netif, struct pbuf * buf) |
| { |
| const TapInterface * tapif = (const TapInterface *) (netif->state); |
| err_t retval = ERR_OK; |
| struct pbuf * outBuf; |
| int written; |
| |
| if (buf->tot_len > buf->len) |
| { |
| // Allocate a buffer from the buffer pool. Fail if none available. |
| outBuf = pbuf_alloc(PBUF_RAW, buf->tot_len + PBUF_LINK_ENCAPSULATION_HLEN, PBUF_POOL); |
| if (outBuf == NULL) |
| { |
| fprintf(stderr, "TapInterface: Failed to allocate buffer\n"); |
| retval = ERR_MEM; |
| goto done; |
| } |
| |
| // Fail if the buffer is not big enough to hold the output data. |
| if (outBuf->tot_len != outBuf->len) |
| { |
| fprintf(stderr, "TapInterface: Output data bigger than single PBUF\n"); |
| retval = ERR_BUF; |
| goto done; |
| } |
| |
| // Reserve the space needed by WICED for its buffer management. |
| pbuf_header(outBuf, -PBUF_LINK_ENCAPSULATION_HLEN); |
| |
| // Copy output data to the new buffer. |
| retval = pbuf_copy(outBuf, buf); |
| if (retval != ERR_OK) |
| goto done; |
| } |
| |
| // Otherwise send using the supplied buffer. |
| else |
| outBuf = buf; |
| |
| written = write(tapif->fd, outBuf->payload, outBuf->tot_len); |
| if (written == -1) |
| { |
| snmp_inc_ifoutdiscards(netif); |
| perror("TapInterface: write failed"); |
| retval = ERR_IF; |
| } |
| else |
| { |
| snmp_add_ifoutoctets(netif, written); |
| } |
| |
| done: |
| if (outBuf != NULL && outBuf != buf) |
| pbuf_free(outBuf); |
| |
| return retval; |
| } |
| |
| /** |
| * This is the LwIP TUN/TAP shim interface low level input method. |
| * |
| * When input has been identified as pending on the LwIP TUN/TAP shim |
| * interface, this API allocates a buffer and reads the packet from |
| * the underlying host OS into the buffer and returns it. |
| * |
| * @param[in] tapif A pointer to the LwIP TUN/TAP shim interface |
| * from which to read pending input. |
| * |
| * @param[in] netif A pointer to the LwIP native interface |
| * associated with the TUN/TAP shim interface. |
| * |
| * @returns A pointer to the buffer containing the read input on |
| * success; otherwise, NULL on error. |
| * |
| * @sa #TapInterface_Select |
| * |
| */ |
| static struct pbuf * TapInterface_low_level_input(TapInterface * tapif, struct netif * netif) |
| { |
| struct pbuf *p, *q; |
| u16_t len; |
| char buf[2048]; |
| char * bufptr; |
| |
| /* Obtain the size of the packet and put it into the "len" |
| variable. */ |
| len = read(tapif->fd, buf, sizeof(buf)); |
| snmp_add_ifinoctets(netif, len); |
| |
| /* We allocate a pbuf chain of pbufs from the pool. */ |
| p = pbuf_alloc(PBUF_LINK, len, PBUF_POOL); |
| |
| if (p != NULL) |
| { |
| /* We iterate over the pbuf chain until we have read the entire |
| packet into the pbuf. */ |
| bufptr = &buf[0]; |
| for (q = p; q != NULL; q = q->next) |
| { |
| /* Read enough bytes to fill this pbuf in the chain. The |
| available data in the pbuf is given by the q->len |
| variable. */ |
| /* read data into(q->payload, q->len); */ |
| memcpy(q->payload, bufptr, q->len); |
| bufptr += q->len; |
| } |
| /* acknowledge that packet has been read(); */ |
| } |
| else |
| { |
| /* drop packet(); */ |
| snmp_inc_ifindiscards(netif); |
| printf("Could not allocate pbufs\n"); |
| } |
| |
| return p; |
| } |
| |
| /** |
| * LwIP netif_add setup callback function for LwIP TUN/TAP shim |
| * interfaces. |
| * |
| * The interface mimics / effects an Ethernet-like interface and, |
| * consequently, reuses and leverages existing LwIP low-level APIs |
| * for such interfaces. |
| * |
| * This interface should / will be called by LwIP's netif_add |
| * function for a LwIP TUN/TAP shim interface. \c #TapInterface_Init |
| * should have been called prior to invoking netif_add with this |
| * callback. |
| * |
| * @param[in,out] netif A pointer to the LwIP netif associated with the |
| * TUN/TAP shim interface. |
| * |
| * @retval #ERR_OK on successfully setting up the TUN/TAP interface. |
| * |
| * @sa #TapInterface_Init |
| * @sa #TapInterface_Select |
| * |
| */ |
| err_t TapInterface_SetupNetif(struct netif * netif) |
| { |
| const TapInterface * tapif = (const TapInterface *) (netif->state); |
| |
| /* As far as LwIP is concerned, the network interface is an |
| * Ethernet-like interface, so set it up accordingly, reusing |
| * existing LwIP APIs for such interfaces where possible. |
| */ |
| |
| netif->name[0] = tapif->interfaceName[0]; |
| netif->name[1] = tapif->interfaceName[1]; |
| netif->output = etharp_output; |
| #if LWIP_IPV6 |
| netif->output_ip6 = ethip6_output; |
| #endif /* LWIP_IPV6 */ |
| netif->linkoutput = TapInterface_low_level_output; |
| netif->mtu = 1500; |
| |
| netif->flags |= (NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP); |
| #if LWIP_IPV4 |
| netif->flags |= (NETIF_FLAG_IGMP); |
| #endif |
| #if LWIP_IPV6 |
| netif->flags |= (NETIF_FLAG_MLD6); |
| #endif |
| |
| netif->hwaddr_len = kMacLength; |
| |
| memcpy(netif->hwaddr, tapif->macAddr, kMacLength); |
| |
| return ERR_OK; |
| } |
| |
| /** |
| * Establish an LwIP TUN/TAP interface on the underlying host OS with |
| * the specified name. |
| * |
| * This interface should be invoked before either \c #TapInterface_SetupNetif |
| * or \c #TapInterface_Select are invoked. |
| * |
| * @param[out] tapif A pointer to storage for the established |
| * TUN/TAP interface details. |
| * |
| * @param[in] interfaceName A pointer to a NULL-terminated C string |
| * containing the name of the TUN/TAP interface. |
| * |
| * @param[in] macAddr An optional pointer to the MAC address to be |
| * used for the TUN/TAP interface. |
| * |
| * @retval #ERR_OK on successfully establishing the TUN/TAP |
| * interface. |
| * |
| * @retval #ERR_ARG if \c tapif is NULL or if \c interfaceName is |
| * too long. |
| * |
| * @retval #ERR_IF if the OS-specific TUN/TAP driver cannot be |
| * opened or if the requested TUN/TAP device |
| * cannot be created. |
| * |
| * @sa #TapInterface_SetupNetif |
| * @sa #TapInterface_Select |
| * |
| */ |
| err_t TapInterface_Init(TapInterface * tapif, const char * interfaceName, u8_t * macAddr) |
| { |
| #if defined(linux) |
| struct ifreq ifr; |
| #endif |
| |
| /* The TUN/TAP interface storage pointer is required; error out if |
| * it hasn't been provided. |
| */ |
| |
| if (tapif == NULL) |
| return ERR_ARG; |
| |
| /* Set the TUN/TAP interface storage to initial defaults. |
| */ |
| |
| memset(tapif, 0, sizeof(*tapif)); |
| tapif->fd = -1; |
| |
| /* Intialize the TUN/TAP interface name and MAC address. If the |
| * optional MAC address was not provided, use the current process |
| * identifier as a MAC address. |
| */ |
| |
| tapif->interfaceName = interfaceName; |
| |
| if (macAddr != NULL) |
| { |
| memcpy(tapif->macAddr, macAddr, kMacLength); |
| } |
| else |
| { |
| const u32_t pid = htonl((u32_t) getpid()); |
| memset(tapif->macAddr, 0, kMacLength); |
| memcpy(tapif->macAddr + 2, &pid, sizeof(pid)); |
| } |
| |
| /* Attempt to open the OS-specific TUN/TAP driver control interface. |
| */ |
| |
| tapif->fd = open(DEVTAP, O_RDWR); |
| if (tapif->fd == -1) |
| { |
| perror("TapInterface: unable to open " DEVTAP); |
| return ERR_IF; |
| } |
| |
| #if defined(linux) |
| /* On Linux, prepare and issue the TUNSETIFF ioctl to establish a |
| * TAP interface (IFF_TAP) with the previously-specified name and |
| * no packet information (IFF_NO_PI). |
| */ |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| ifr.ifr_flags = (IFF_TAP | IFF_NO_PI); |
| |
| if (strlen(tapif->interfaceName) >= sizeof(ifr.ifr_name)) |
| { |
| perror("TapInterface: invalid device name"); |
| return ERR_ARG; |
| } |
| |
| strcpy(ifr.ifr_name, tapif->interfaceName); |
| |
| if (ioctl(tapif->fd, TUNSETIFF, (void *) &ifr) < 0) |
| { |
| perror("TapInterface: ioctl(TUNSETIFF) failed"); |
| return ERR_IF; |
| } |
| |
| #else |
| #warning "The LwIP TAP/TUN interface may not be fully-supported on your platform." |
| #endif /* defined(linux) */ |
| |
| return ERR_OK; |
| } |
| |
| /** |
| * Check the LwIP TUN/TAP shim interface to see if any input / read |
| * activity is pending and, if there is, process it. |
| * |
| * @param[in] tapif An array of LwIP TUN/TAP shim interfaces |
| * to check and, if necessary, to process the |
| * input for. |
| * |
| * @param[in] netif An array of the LwIP native interfaces |
| * associated with the TUN/TAP shim interface. |
| * |
| * @param[in] sleepTime The interval that the call should block for |
| * waiting for input. |
| * |
| * @param[in] numIntfs The number of elements in the tapif and netif arrays. |
| * |
| * @retval >= 0 on a successful check and/or processing of pending input. |
| * |
| * @retval -EINVAL if either \c tapif or \c netif are NULL. |
| * |
| * @sa #TapInterface_Init |
| * @sa #TapInterface_SetupNetif |
| * |
| */ |
| int TapInterface_Select(TapInterface * tapif, struct netif * netif, struct timeval sleepTime, size_t numIntfs) |
| { |
| fd_set readfds; |
| int ret; |
| size_t j; |
| |
| if ((tapif == NULL) || (netif == NULL) || (numIntfs == 0)) |
| { |
| return -EINVAL; |
| } |
| |
| FD_ZERO(&readfds); |
| |
| for (j = 0; j < numIntfs; j++) |
| { |
| FD_SET(tapif[j].fd, &readfds); |
| } |
| |
| ret = select(tapif[numIntfs - 1].fd + 1, &readfds, NULL, NULL, &sleepTime); |
| if (ret > 0) |
| { |
| for (j = 0; j < numIntfs; j++) |
| { |
| if (!FD_ISSET(tapif[j].fd, &readfds)) |
| continue; |
| |
| struct pbuf * p = TapInterface_low_level_input(&(tapif[j]), &(netif[j])); |
| if (p != NULL) |
| { |
| #if LINK_STATS |
| lwip_stats.link.recv++; |
| #endif /* LINK_STATS */ |
| |
| netif[j].input(p, &(netif[j])); |
| } |
| } |
| } |
| |
| return ret; |
| } |
