281 lines
7.5 KiB
C
281 lines
7.5 KiB
C
/*
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* QEMU System Emulator
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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* Copyright (c) 2009 Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "tap_int.h"
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#include "tap-linux.h"
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#include "net/tap.h"
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#include <net/if.h>
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#include <sys/ioctl.h>
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#include "sysemu/sysemu.h"
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#include "qemu-common.h"
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#include "qemu/error-report.h"
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#define PATH_NET_TUN "/dev/net/tun"
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int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
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int vnet_hdr_required, int mq_required)
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{
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struct ifreq ifr;
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int fd, ret;
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int len = sizeof(struct virtio_net_hdr);
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unsigned int features;
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TFR(fd = open(PATH_NET_TUN, O_RDWR));
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if (fd < 0) {
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error_report("could not open %s: %m", PATH_NET_TUN);
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return -1;
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}
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memset(&ifr, 0, sizeof(ifr));
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ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
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if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
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error_report("warning: TUNGETFEATURES failed: %s", strerror(errno));
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features = 0;
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}
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if (features & IFF_ONE_QUEUE) {
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ifr.ifr_flags |= IFF_ONE_QUEUE;
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}
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if (*vnet_hdr) {
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if (features & IFF_VNET_HDR) {
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*vnet_hdr = 1;
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ifr.ifr_flags |= IFF_VNET_HDR;
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} else {
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*vnet_hdr = 0;
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}
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if (vnet_hdr_required && !*vnet_hdr) {
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error_report("vnet_hdr=1 requested, but no kernel "
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"support for IFF_VNET_HDR available");
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close(fd);
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return -1;
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}
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/*
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* Make sure vnet header size has the default value: for a persistent
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* tap it might have been modified e.g. by another instance of qemu.
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* Ignore errors since old kernels do not support this ioctl: in this
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* case the header size implicitly has the correct value.
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*/
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ioctl(fd, TUNSETVNETHDRSZ, &len);
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}
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if (mq_required) {
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if (!(features & IFF_MULTI_QUEUE)) {
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error_report("multiqueue required, but no kernel "
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"support for IFF_MULTI_QUEUE available");
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close(fd);
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return -1;
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} else {
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ifr.ifr_flags |= IFF_MULTI_QUEUE;
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}
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}
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if (ifname[0] != '\0')
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pstrcpy(ifr.ifr_name, IFNAMSIZ, ifname);
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else
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pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d");
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ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
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if (ret != 0) {
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if (ifname[0] != '\0') {
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error_report("could not configure %s (%s): %m", PATH_NET_TUN, ifr.ifr_name);
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} else {
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error_report("could not configure %s: %m", PATH_NET_TUN);
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}
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close(fd);
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return -1;
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}
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pstrcpy(ifname, ifname_size, ifr.ifr_name);
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fcntl(fd, F_SETFL, O_NONBLOCK);
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return fd;
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}
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/* sndbuf implements a kind of flow control for tap.
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* Unfortunately when it's enabled, and packets are sent
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* to other guests on the same host, the receiver
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* can lock up the transmitter indefinitely.
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*
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* To avoid packet loss, sndbuf should be set to a value lower than the tx
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* queue capacity of any destination network interface.
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* Ethernet NICs generally have txqueuelen=1000, so 1Mb is
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* a good value, given a 1500 byte MTU.
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*/
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#define TAP_DEFAULT_SNDBUF 0
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int tap_set_sndbuf(int fd, const NetdevTapOptions *tap)
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{
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int sndbuf;
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sndbuf = !tap->has_sndbuf ? TAP_DEFAULT_SNDBUF :
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tap->sndbuf > INT_MAX ? INT_MAX :
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tap->sndbuf;
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if (!sndbuf) {
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sndbuf = INT_MAX;
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}
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if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && tap->has_sndbuf) {
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error_report("TUNSETSNDBUF ioctl failed: %s", strerror(errno));
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return -1;
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}
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return 0;
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}
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int tap_probe_vnet_hdr(int fd)
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{
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struct ifreq ifr;
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if (ioctl(fd, TUNGETIFF, &ifr) != 0) {
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error_report("TUNGETIFF ioctl() failed: %s", strerror(errno));
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return 0;
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}
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return ifr.ifr_flags & IFF_VNET_HDR;
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}
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int tap_probe_has_ufo(int fd)
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{
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unsigned offload;
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offload = TUN_F_CSUM | TUN_F_UFO;
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if (ioctl(fd, TUNSETOFFLOAD, offload) < 0)
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return 0;
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return 1;
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}
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/* Verify that we can assign given length */
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int tap_probe_vnet_hdr_len(int fd, int len)
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{
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int orig;
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if (ioctl(fd, TUNGETVNETHDRSZ, &orig) == -1) {
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return 0;
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}
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if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) {
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return 0;
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}
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/* Restore original length: we can't handle failure. */
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if (ioctl(fd, TUNSETVNETHDRSZ, &orig) == -1) {
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fprintf(stderr, "TUNGETVNETHDRSZ ioctl() failed: %s. Exiting.\n",
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strerror(errno));
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abort();
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return -errno;
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}
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return 1;
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}
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void tap_fd_set_vnet_hdr_len(int fd, int len)
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{
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if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) {
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fprintf(stderr, "TUNSETVNETHDRSZ ioctl() failed: %s. Exiting.\n",
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strerror(errno));
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abort();
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}
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}
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void tap_fd_set_offload(int fd, int csum, int tso4,
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int tso6, int ecn, int ufo)
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{
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unsigned int offload = 0;
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/* Check if our kernel supports TUNSETOFFLOAD */
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if (ioctl(fd, TUNSETOFFLOAD, 0) != 0 && errno == EINVAL) {
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return;
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}
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if (csum) {
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offload |= TUN_F_CSUM;
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if (tso4)
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offload |= TUN_F_TSO4;
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if (tso6)
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offload |= TUN_F_TSO6;
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if ((tso4 || tso6) && ecn)
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offload |= TUN_F_TSO_ECN;
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if (ufo)
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offload |= TUN_F_UFO;
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}
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if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
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offload &= ~TUN_F_UFO;
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if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
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fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",
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strerror(errno));
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}
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}
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}
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/* Enable a specific queue of tap. */
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int tap_fd_enable(int fd)
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{
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struct ifreq ifr;
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int ret;
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memset(&ifr, 0, sizeof(ifr));
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ifr.ifr_flags = IFF_ATTACH_QUEUE;
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ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr);
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if (ret != 0) {
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error_report("could not enable queue");
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}
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return ret;
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}
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/* Disable a specific queue of tap/ */
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int tap_fd_disable(int fd)
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{
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struct ifreq ifr;
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int ret;
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memset(&ifr, 0, sizeof(ifr));
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ifr.ifr_flags = IFF_DETACH_QUEUE;
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ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr);
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if (ret != 0) {
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error_report("could not disable queue");
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}
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return ret;
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}
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int tap_fd_get_ifname(int fd, char *ifname)
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{
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struct ifreq ifr;
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if (ioctl(fd, TUNGETIFF, &ifr) != 0) {
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error_report("TUNGETIFF ioctl() failed: %s",
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strerror(errno));
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return -1;
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}
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pstrcpy(ifname, sizeof(ifr.ifr_name), ifr.ifr_name);
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return 0;
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}
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