79 lines
2.6 KiB
C
79 lines
2.6 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 "net/tap.h"
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#include "net/tap-linux.h"
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#include <net/if.h>
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#include <sys/ioctl.h>
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#include "sysemu.h"
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#include "qemu-common.h"
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int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
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{
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struct ifreq ifr;
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int fd, ret;
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TFR(fd = open("/dev/net/tun", O_RDWR));
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if (fd < 0) {
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fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n");
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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 (*vnet_hdr) {
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unsigned int features;
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if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
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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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}
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if (vnet_hdr_required && !*vnet_hdr) {
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qemu_error("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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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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fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n");
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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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