Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging
[qemu.git] / net / tap-linux.c
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 "tap_int.h"
28 #include "tap-linux.h"
29 #include "net/tap.h"
30
31 #include <net/if.h>
32 #include <sys/ioctl.h>
33
34 #include "sysemu/sysemu.h"
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 error_report("warning: 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 }