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/*-
* BSD LICENSE
*
* Copyright(c) 2016 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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
* OWNER 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.
*/
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <net/if.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#include "vhost_kernel_tap.h"
#include "../virtio_logs.h"
int
vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq)
{
unsigned int tap_features;
int sndbuf = INT_MAX;
struct ifreq ifr;
int tapfd;
unsigned int offload =
TUN_F_CSUM |
TUN_F_TSO4 |
TUN_F_TSO6 |
TUN_F_TSO_ECN |
TUN_F_UFO;
/* TODO:
* 1. verify we can get/set vnet_hdr_len, tap_probe_vnet_hdr_len
* 2. get number of memory regions from vhost module parameter
* max_mem_regions, supported in newer version linux kernel
*/
tapfd = open(PATH_NET_TUN, O_RDWR);
if (tapfd < 0) {
PMD_DRV_LOG(ERR, "fail to open %s: %s",
PATH_NET_TUN, strerror(errno));
return -1;
}
/* Construct ifr */
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
if (ioctl(tapfd, TUNGETFEATURES, &tap_features) == -1) {
PMD_DRV_LOG(ERR, "TUNGETFEATURES failed: %s", strerror(errno));
goto error;
}
if (tap_features & IFF_ONE_QUEUE)
ifr.ifr_flags |= IFF_ONE_QUEUE;
/* Let tap instead of vhost-net handle vnet header, as the latter does
* not support offloading. And in this case, we should not set feature
* bit VHOST_NET_F_VIRTIO_NET_HDR.
*/
if (tap_features & IFF_VNET_HDR) {
ifr.ifr_flags |= IFF_VNET_HDR;
} else {
PMD_DRV_LOG(ERR, "TAP does not support IFF_VNET_HDR");
goto error;
}
if (req_mq)
ifr.ifr_flags |= IFF_MULTI_QUEUE;
if (*p_ifname)
strncpy(ifr.ifr_name, *p_ifname, IFNAMSIZ - 1);
else
strncpy(ifr.ifr_name, "tap%d", IFNAMSIZ - 1);
if (ioctl(tapfd, TUNSETIFF, (void *)&ifr) == -1) {
PMD_DRV_LOG(ERR, "TUNSETIFF failed: %s", strerror(errno));
goto error;
}
fcntl(tapfd, F_SETFL, O_NONBLOCK);
if (ioctl(tapfd, TUNSETVNETHDRSZ, &hdr_size) < 0) {
PMD_DRV_LOG(ERR, "TUNSETVNETHDRSZ failed: %s", strerror(errno));
goto error;
}
if (ioctl(tapfd, TUNSETSNDBUF, &sndbuf) < 0) {
PMD_DRV_LOG(ERR, "TUNSETSNDBUF failed: %s", strerror(errno));
goto error;
}
/* TODO: before set the offload capabilities, we'd better (1) check
* negotiated features to see if necessary to offload; (2) query tap
* to see if it supports the offload capabilities.
*/
if (ioctl(tapfd, TUNSETOFFLOAD, offload) != 0)
PMD_DRV_LOG(ERR, "TUNSETOFFLOAD ioctl() failed: %s",
strerror(errno));
if (!(*p_ifname))
*p_ifname = strdup(ifr.ifr_name);
return tapfd;
error:
close(tapfd);
return -1;
}
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