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c28b1c10 MM |
1 | /* |
2 | * QEMU System Emulator | |
3 | * | |
4 | * Copyright (c) 2003-2008 Fabrice Bellard | |
5 | * Copyright (c) 2009 Red Hat, Inc. | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
8 | * of this software and associated documentation files (the "Software"), to deal | |
9 | * in the Software without restriction, including without limitation the rights | |
10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
11 | * copies of the Software, and to permit persons to whom the Software is | |
12 | * furnished to do so, subject to the following conditions: | |
13 | * | |
14 | * The above copyright notice and this permission notice shall be included in | |
15 | * all copies or substantial portions of the Software. | |
16 | * | |
17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
20 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
23 | * THE SOFTWARE. | |
24 | */ | |
25 | ||
26 | #include "net/tap.h" | |
27 | #include "net/tap-linux.h" | |
28 | ||
29 | #include <net/if.h> | |
30 | #include <sys/ioctl.h> | |
31 | ||
32 | #include "sysemu.h" | |
33 | #include "qemu-common.h" | |
34 | ||
35 | int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required) | |
36 | { | |
37 | struct ifreq ifr; | |
38 | int fd, ret; | |
39 | ||
40 | TFR(fd = open("/dev/net/tun", O_RDWR)); | |
41 | if (fd < 0) { | |
42 | fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n"); | |
43 | return -1; | |
44 | } | |
45 | memset(&ifr, 0, sizeof(ifr)); | |
46 | ifr.ifr_flags = IFF_TAP | IFF_NO_PI; | |
47 | ||
48 | if (*vnet_hdr) { | |
49 | unsigned int features; | |
50 | ||
51 | if (ioctl(fd, TUNGETFEATURES, &features) == 0 && | |
52 | features & IFF_VNET_HDR) { | |
53 | *vnet_hdr = 1; | |
54 | ifr.ifr_flags |= IFF_VNET_HDR; | |
55 | } | |
56 | ||
57 | if (vnet_hdr_required && !*vnet_hdr) { | |
58 | qemu_error("vnet_hdr=1 requested, but no kernel " | |
59 | "support for IFF_VNET_HDR available"); | |
60 | close(fd); | |
61 | return -1; | |
62 | } | |
63 | } | |
64 | ||
65 | if (ifname[0] != '\0') | |
66 | pstrcpy(ifr.ifr_name, IFNAMSIZ, ifname); | |
67 | else | |
68 | pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d"); | |
69 | ret = ioctl(fd, TUNSETIFF, (void *) &ifr); | |
70 | if (ret != 0) { | |
71 | fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n"); | |
72 | close(fd); | |
73 | return -1; | |
74 | } | |
75 | pstrcpy(ifname, ifname_size, ifr.ifr_name); | |
76 | fcntl(fd, F_SETFL, O_NONBLOCK); | |
77 | return fd; | |
78 | } |