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 "qemu/osdep.h" |
27 | #include "qemu-common.h" |
28 | #include "tap_int.h" |
29 | #include "tap-linux.h" |
30 | #include "net/tap.h" |
31 | |
32 | #include <net/if.h> |
33 | #include <sys/ioctl.h> |
34 | |
35 | #include "qapi/error.h" |
36 | #include "qemu/error-report.h" |
37 | #include "qemu/cutils.h" |
38 | |
39 | #define PATH_NET_TUN "/dev/net/tun" |
40 | |
41 | int tap_open(char *ifname, int ifname_size, int *vnet_hdr, |
42 | int vnet_hdr_required, int mq_required, Error **errp) |
43 | { |
44 | struct ifreq ifr; |
45 | int fd, ret; |
46 | int len = sizeof(struct virtio_net_hdr); |
47 | unsigned int features; |
48 | |
49 | TFR(fd = open(PATH_NET_TUN, O_RDWR)); |
50 | if (fd < 0) { |
51 | error_setg_errno(errp, errno, "could not open %s" , PATH_NET_TUN); |
52 | return -1; |
53 | } |
54 | memset(&ifr, 0, sizeof(ifr)); |
55 | ifr.ifr_flags = IFF_TAP | IFF_NO_PI; |
56 | |
57 | if (ioctl(fd, TUNGETFEATURES, &features) == -1) { |
58 | warn_report("TUNGETFEATURES failed: %s" , strerror(errno)); |
59 | features = 0; |
60 | } |
61 | |
62 | if (features & IFF_ONE_QUEUE) { |
63 | ifr.ifr_flags |= IFF_ONE_QUEUE; |
64 | } |
65 | |
66 | if (*vnet_hdr) { |
67 | if (features & IFF_VNET_HDR) { |
68 | *vnet_hdr = 1; |
69 | ifr.ifr_flags |= IFF_VNET_HDR; |
70 | } else { |
71 | *vnet_hdr = 0; |
72 | } |
73 | |
74 | if (vnet_hdr_required && !*vnet_hdr) { |
75 | error_setg(errp, "vnet_hdr=1 requested, but no kernel " |
76 | "support for IFF_VNET_HDR available" ); |
77 | close(fd); |
78 | return -1; |
79 | } |
80 | /* |
81 | * Make sure vnet header size has the default value: for a persistent |
82 | * tap it might have been modified e.g. by another instance of qemu. |
83 | * Ignore errors since old kernels do not support this ioctl: in this |
84 | * case the header size implicitly has the correct value. |
85 | */ |
86 | ioctl(fd, TUNSETVNETHDRSZ, &len); |
87 | } |
88 | |
89 | if (mq_required) { |
90 | if (!(features & IFF_MULTI_QUEUE)) { |
91 | error_setg(errp, "multiqueue required, but no kernel " |
92 | "support for IFF_MULTI_QUEUE available" ); |
93 | close(fd); |
94 | return -1; |
95 | } else { |
96 | ifr.ifr_flags |= IFF_MULTI_QUEUE; |
97 | } |
98 | } |
99 | |
100 | if (ifname[0] != '\0') |
101 | pstrcpy(ifr.ifr_name, IFNAMSIZ, ifname); |
102 | else |
103 | pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d" ); |
104 | ret = ioctl(fd, TUNSETIFF, (void *) &ifr); |
105 | if (ret != 0) { |
106 | if (ifname[0] != '\0') { |
107 | error_setg_errno(errp, errno, "could not configure %s (%s)" , |
108 | PATH_NET_TUN, ifr.ifr_name); |
109 | } else { |
110 | error_setg_errno(errp, errno, "could not configure %s" , |
111 | PATH_NET_TUN); |
112 | } |
113 | close(fd); |
114 | return -1; |
115 | } |
116 | pstrcpy(ifname, ifname_size, ifr.ifr_name); |
117 | fcntl(fd, F_SETFL, O_NONBLOCK); |
118 | return fd; |
119 | } |
120 | |
121 | /* sndbuf implements a kind of flow control for tap. |
122 | * Unfortunately when it's enabled, and packets are sent |
123 | * to other guests on the same host, the receiver |
124 | * can lock up the transmitter indefinitely. |
125 | * |
126 | * To avoid packet loss, sndbuf should be set to a value lower than the tx |
127 | * queue capacity of any destination network interface. |
128 | * Ethernet NICs generally have txqueuelen=1000, so 1Mb is |
129 | * a good value, given a 1500 byte MTU. |
130 | */ |
131 | #define TAP_DEFAULT_SNDBUF 0 |
132 | |
133 | void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp) |
134 | { |
135 | int sndbuf; |
136 | |
137 | sndbuf = !tap->has_sndbuf ? TAP_DEFAULT_SNDBUF : |
138 | tap->sndbuf > INT_MAX ? INT_MAX : |
139 | tap->sndbuf; |
140 | |
141 | if (!sndbuf) { |
142 | sndbuf = INT_MAX; |
143 | } |
144 | |
145 | if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && tap->has_sndbuf) { |
146 | error_setg_errno(errp, errno, "TUNSETSNDBUF ioctl failed" ); |
147 | } |
148 | } |
149 | |
150 | int tap_probe_vnet_hdr(int fd) |
151 | { |
152 | struct ifreq ifr; |
153 | |
154 | if (ioctl(fd, TUNGETIFF, &ifr) != 0) { |
155 | error_report("TUNGETIFF ioctl() failed: %s" , strerror(errno)); |
156 | return 0; |
157 | } |
158 | |
159 | return ifr.ifr_flags & IFF_VNET_HDR; |
160 | } |
161 | |
162 | int tap_probe_has_ufo(int fd) |
163 | { |
164 | unsigned offload; |
165 | |
166 | offload = TUN_F_CSUM | TUN_F_UFO; |
167 | |
168 | if (ioctl(fd, TUNSETOFFLOAD, offload) < 0) |
169 | return 0; |
170 | |
171 | return 1; |
172 | } |
173 | |
174 | /* Verify that we can assign given length */ |
175 | int tap_probe_vnet_hdr_len(int fd, int len) |
176 | { |
177 | int orig; |
178 | if (ioctl(fd, TUNGETVNETHDRSZ, &orig) == -1) { |
179 | return 0; |
180 | } |
181 | if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) { |
182 | return 0; |
183 | } |
184 | /* Restore original length: we can't handle failure. */ |
185 | if (ioctl(fd, TUNSETVNETHDRSZ, &orig) == -1) { |
186 | fprintf(stderr, "TUNGETVNETHDRSZ ioctl() failed: %s. Exiting.\n" , |
187 | strerror(errno)); |
188 | abort(); |
189 | return -errno; |
190 | } |
191 | return 1; |
192 | } |
193 | |
194 | void tap_fd_set_vnet_hdr_len(int fd, int len) |
195 | { |
196 | if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) { |
197 | fprintf(stderr, "TUNSETVNETHDRSZ ioctl() failed: %s. Exiting.\n" , |
198 | strerror(errno)); |
199 | abort(); |
200 | } |
201 | } |
202 | |
203 | int tap_fd_set_vnet_le(int fd, int is_le) |
204 | { |
205 | int arg = is_le ? 1 : 0; |
206 | |
207 | if (!ioctl(fd, TUNSETVNETLE, &arg)) { |
208 | return 0; |
209 | } |
210 | |
211 | /* Check if our kernel supports TUNSETVNETLE */ |
212 | if (errno == EINVAL) { |
213 | return -errno; |
214 | } |
215 | |
216 | error_report("TUNSETVNETLE ioctl() failed: %s." , strerror(errno)); |
217 | abort(); |
218 | } |
219 | |
220 | int tap_fd_set_vnet_be(int fd, int is_be) |
221 | { |
222 | int arg = is_be ? 1 : 0; |
223 | |
224 | if (!ioctl(fd, TUNSETVNETBE, &arg)) { |
225 | return 0; |
226 | } |
227 | |
228 | /* Check if our kernel supports TUNSETVNETBE */ |
229 | if (errno == EINVAL) { |
230 | return -errno; |
231 | } |
232 | |
233 | error_report("TUNSETVNETBE ioctl() failed: %s." , strerror(errno)); |
234 | abort(); |
235 | } |
236 | |
237 | void tap_fd_set_offload(int fd, int csum, int tso4, |
238 | int tso6, int ecn, int ufo) |
239 | { |
240 | unsigned int offload = 0; |
241 | |
242 | /* Check if our kernel supports TUNSETOFFLOAD */ |
243 | if (ioctl(fd, TUNSETOFFLOAD, 0) != 0 && errno == EINVAL) { |
244 | return; |
245 | } |
246 | |
247 | if (csum) { |
248 | offload |= TUN_F_CSUM; |
249 | if (tso4) |
250 | offload |= TUN_F_TSO4; |
251 | if (tso6) |
252 | offload |= TUN_F_TSO6; |
253 | if ((tso4 || tso6) && ecn) |
254 | offload |= TUN_F_TSO_ECN; |
255 | if (ufo) |
256 | offload |= TUN_F_UFO; |
257 | } |
258 | |
259 | if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) { |
260 | offload &= ~TUN_F_UFO; |
261 | if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) { |
262 | fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n" , |
263 | strerror(errno)); |
264 | } |
265 | } |
266 | } |
267 | |
268 | /* Enable a specific queue of tap. */ |
269 | int tap_fd_enable(int fd) |
270 | { |
271 | struct ifreq ifr; |
272 | int ret; |
273 | |
274 | memset(&ifr, 0, sizeof(ifr)); |
275 | |
276 | ifr.ifr_flags = IFF_ATTACH_QUEUE; |
277 | ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr); |
278 | |
279 | if (ret != 0) { |
280 | error_report("could not enable queue" ); |
281 | } |
282 | |
283 | return ret; |
284 | } |
285 | |
286 | /* Disable a specific queue of tap/ */ |
287 | int tap_fd_disable(int fd) |
288 | { |
289 | struct ifreq ifr; |
290 | int ret; |
291 | |
292 | memset(&ifr, 0, sizeof(ifr)); |
293 | |
294 | ifr.ifr_flags = IFF_DETACH_QUEUE; |
295 | ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr); |
296 | |
297 | if (ret != 0) { |
298 | error_report("could not disable queue" ); |
299 | } |
300 | |
301 | return ret; |
302 | } |
303 | |
304 | int tap_fd_get_ifname(int fd, char *ifname) |
305 | { |
306 | struct ifreq ifr; |
307 | |
308 | if (ioctl(fd, TUNGETIFF, &ifr) != 0) { |
309 | error_report("TUNGETIFF ioctl() failed: %s" , |
310 | strerror(errno)); |
311 | return -1; |
312 | } |
313 | |
314 | pstrcpy(ifname, sizeof(ifr.ifr_name), ifr.ifr_name); |
315 | return 0; |
316 | } |
317 | |