aboutsummaryrefslogtreecommitdiff
path: root/net/tap.c
blob: 937d9429eb5ac34d527d4fad918d7188b67fc391 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 * Copyright (c) 2009 Red Hat, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "net/tap.h"

#include "config-host.h"

#include <signal.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <net/if.h>

#include "net.h"
#include "sysemu.h"
#include "qemu-char.h"
#include "qemu-common.h"
#include "qemu-error.h"

#include "net/tap-linux.h"

#include "hw/vhost_net.h"

/* Maximum GSO packet size (64k) plus plenty of room for
 * the ethernet and virtio_net headers
 */
#define TAP_BUFSIZE (4096 + 65536)

typedef struct TAPState {
    VLANClientState nc;
    int fd;
    char down_script[1024];
    char down_script_arg[128];
    uint8_t buf[TAP_BUFSIZE];
    unsigned int read_poll : 1;
    unsigned int write_poll : 1;
    unsigned int using_vnet_hdr : 1;
    unsigned int has_ufo: 1;
    VHostNetState *vhost_net;
    unsigned host_vnet_hdr_len;
} TAPState;

static int launch_script(const char *setup_script, const char *ifname, int fd);

static int tap_can_send(void *opaque);
static void tap_send(void *opaque);
static void tap_writable(void *opaque);

static void tap_update_fd_handler(TAPState *s)
{
    qemu_set_fd_handler2(s->fd,
                         s->read_poll  ? tap_can_send : NULL,
                         s->read_poll  ? tap_send     : NULL,
                         s->write_poll ? tap_writable : NULL,
                         s);
}

static void tap_read_poll(TAPState *s, int enable)
{
    s->read_poll = !!enable;
    tap_update_fd_handler(s);
}

static void tap_write_poll(TAPState *s, int enable)
{
    s->write_poll = !!enable;
    tap_update_fd_handler(s);
}

static void tap_writable(void *opaque)
{
    TAPState *s = opaque;

    tap_write_poll(s, 0);

    qemu_flush_queued_packets(&s->nc);
}

static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
{
    ssize_t len;

    do {
        len = writev(s->fd, iov, iovcnt);
    } while (len == -1 && errno == EINTR);

    if (len == -1 && errno == EAGAIN) {
        tap_write_poll(s, 1);
        return 0;
    }

    return len;
}

static ssize_t tap_receive_iov(VLANClientState *nc, const struct iovec *iov,
                               int iovcnt)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    const struct iovec *iovp = iov;
    struct iovec iov_copy[iovcnt + 1];
    struct virtio_net_hdr_mrg_rxbuf hdr = { };

    if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
        iov_copy[0].iov_base = &hdr;
        iov_copy[0].iov_len =  s->host_vnet_hdr_len;
        memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
        iovp = iov_copy;
        iovcnt++;
    }

    return tap_write_packet(s, iovp, iovcnt);
}

static ssize_t tap_receive_raw(VLANClientState *nc, const uint8_t *buf, size_t size)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    struct iovec iov[2];
    int iovcnt = 0;
    struct virtio_net_hdr_mrg_rxbuf hdr = { };

    if (s->host_vnet_hdr_len) {
        iov[iovcnt].iov_base = &hdr;
        iov[iovcnt].iov_len  = s->host_vnet_hdr_len;
        iovcnt++;
    }

    iov[iovcnt].iov_base = (char *)buf;
    iov[iovcnt].iov_len  = size;
    iovcnt++;

    return tap_write_packet(s, iov, iovcnt);
}

static ssize_t tap_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    struct iovec iov[1];

    if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
        return tap_receive_raw(nc, buf, size);
    }

    iov[0].iov_base = (char *)buf;
    iov[0].iov_len  = size;

    return tap_write_packet(s, iov, 1);
}

static int tap_can_send(void *opaque)
{
    TAPState *s = opaque;

    return qemu_can_send_packet(&s->nc);
}

#ifndef __sun__
ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
{
    return read(tapfd, buf, maxlen);
}
#endif

static void tap_send_completed(VLANClientState *nc, ssize_t len)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    tap_read_poll(s, 1);
}

static void tap_send(void *opaque)
{
    TAPState *s = opaque;
    int size;

    do {
        uint8_t *buf = s->buf;

        size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
        if (size <= 0) {
            break;
        }

        if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
            buf  += s->host_vnet_hdr_len;
            size -= s->host_vnet_hdr_len;
        }

        size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
        if (size == 0) {
            tap_read_poll(s, 0);
        }
    } while (size > 0 && qemu_can_send_packet(&s->nc));
}

int tap_has_ufo(VLANClientState *nc)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    assert(nc->info->type == NET_CLIENT_TYPE_TAP);

    return s->has_ufo;
}

int tap_has_vnet_hdr(VLANClientState *nc)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    assert(nc->info->type == NET_CLIENT_TYPE_TAP);

    return !!s->host_vnet_hdr_len;
}

int tap_has_vnet_hdr_len(VLANClientState *nc, int len)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    assert(nc->info->type == NET_CLIENT_TYPE_TAP);

    return tap_probe_vnet_hdr_len(s->fd, len);
}

void tap_set_vnet_hdr_len(VLANClientState *nc, int len)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    assert(nc->info->type == NET_CLIENT_TYPE_TAP);
    assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
           len == sizeof(struct virtio_net_hdr));

    tap_fd_set_vnet_hdr_len(s->fd, len);
    s->host_vnet_hdr_len = len;
}

void tap_using_vnet_hdr(VLANClientState *nc, int using_vnet_hdr)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    using_vnet_hdr = using_vnet_hdr != 0;

    assert(nc->info->type == NET_CLIENT_TYPE_TAP);
    assert(!!s->host_vnet_hdr_len == using_vnet_hdr);

    s->using_vnet_hdr = using_vnet_hdr;
}

void tap_set_offload(VLANClientState *nc, int csum, int tso4,
                     int tso6, int ecn, int ufo)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    return tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
}

static void tap_cleanup(VLANClientState *nc)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);

    if (s->vhost_net) {
        vhost_net_cleanup(s->vhost_net);
        s->vhost_net = NULL;
    }

    qemu_purge_queued_packets(nc);

    if (s->down_script[0])
        launch_script(s->down_script, s->down_script_arg, s->fd);

    tap_read_poll(s, 0);
    tap_write_poll(s, 0);
    close(s->fd);
}

static void tap_poll(VLANClientState *nc, bool enable)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    tap_read_poll(s, enable);
    tap_write_poll(s, enable);
}

int tap_get_fd(VLANClientState *nc)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    assert(nc->info->type == NET_CLIENT_TYPE_TAP);
    return s->fd;
}

/* fd support */

static NetClientInfo net_tap_info = {
    .type = NET_CLIENT_TYPE_TAP,
    .size = sizeof(TAPState),
    .receive = tap_receive,
    .receive_raw = tap_receive_raw,
    .receive_iov = tap_receive_iov,
    .poll = tap_poll,
    .cleanup = tap_cleanup,
};

static TAPState *net_tap_fd_init(VLANState *vlan,
                                 const char *model,
                                 const char *name,
                                 int fd,
                                 int vnet_hdr)
{
    VLANClientState *nc;
    TAPState *s;

    nc = qemu_new_net_client(&net_tap_info, vlan, NULL, model, name);

    s = DO_UPCAST(TAPState, nc, nc);

    s->fd = fd;
    s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
    s->using_vnet_hdr = 0;
    s->has_ufo = tap_probe_has_ufo(s->fd);
    tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
    tap_read_poll(s, 1);
    s->vhost_net = NULL;
    return s;
}

static int launch_script(const char *setup_script, const char *ifname, int fd)
{
    sigset_t oldmask, mask;
    int pid, status;
    char *args[3];
    char **parg;

    sigemptyset(&mask);
    sigaddset(&mask, SIGCHLD);
    sigprocmask(SIG_BLOCK, &mask, &oldmask);

    /* try to launch network script */
    pid = fork();
    if (pid == 0) {
        int open_max = sysconf(_SC_OPEN_MAX), i;

        for (i = 0; i < open_max; i++) {
            if (i != STDIN_FILENO &&
                i != STDOUT_FILENO &&
                i != STDERR_FILENO &&
                i != fd) {
                close(i);
            }
        }
        parg = args;
        *parg++ = (char *)setup_script;
        *parg++ = (char *)ifname;
        *parg = NULL;
        execv(setup_script, args);
        _exit(1);
    } else if (pid > 0) {
        while (waitpid(pid, &status, 0) != pid) {
            /* loop */
        }
        sigprocmask(SIG_SETMASK, &oldmask, NULL);

        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
            return 0;
        }
    }
    fprintf(stderr, "%s: could not launch network script\n", setup_script);
    return -1;
}

static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
{
    int fd, vnet_hdr_required;
    char ifname[128] = {0,};
    const char *setup_script;

    if (qemu_opt_get(opts, "ifname")) {
        pstrcpy(ifname, sizeof(ifname), qemu_opt_get(opts, "ifname"));
    }

    *vnet_hdr = qemu_opt_get_bool(opts, "vnet_hdr", 1);
    if (qemu_opt_get(opts, "vnet_hdr")) {
        vnet_hdr_required = *vnet_hdr;
    } else {
        vnet_hdr_required = 0;
    }

    TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr, vnet_hdr_required));
    if (fd < 0) {
        return -1;
    }

    setup_script = qemu_opt_get(opts, "script");
    if (setup_script &&
        setup_script[0] != '\0' &&
        strcmp(setup_script, "no") != 0 &&
        launch_script(setup_script, ifname, fd)) {
        close(fd);
        return -1;
    }

    qemu_opt_set(opts, "ifname", ifname);

    return fd;
}

int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan)
{
    TAPState *s;
    int fd, vnet_hdr = 0;

    if (qemu_opt_get(opts, "fd")) {
        if (qemu_opt_get(opts, "ifname") ||
            qemu_opt_get(opts, "script") ||
            qemu_opt_get(opts, "downscript") ||
            qemu_opt_get(opts, "vnet_hdr")) {
            error_report("ifname=, script=, downscript= and vnet_hdr= is invalid with fd=");
            return -1;
        }

        fd = net_handle_fd_param(mon, qemu_opt_get(opts, "fd"));
        if (fd == -1) {
            return -1;
        }

        fcntl(fd, F_SETFL, O_NONBLOCK);

        vnet_hdr = tap_probe_vnet_hdr(fd);
    } else {
        if (!qemu_opt_get(opts, "script")) {
            qemu_opt_set(opts, "script", DEFAULT_NETWORK_SCRIPT);
        }

        if (!qemu_opt_get(opts, "downscript")) {
            qemu_opt_set(opts, "downscript", DEFAULT_NETWORK_DOWN_SCRIPT);
        }

        fd = net_tap_init(opts, &vnet_hdr);
        if (fd == -1) {
            return -1;
        }
    }

    s = net_tap_fd_init(vlan, "tap", name, fd, vnet_hdr);
    if (!s) {
        close(fd);
        return -1;
    }

    if (tap_set_sndbuf(s->fd, opts) < 0) {
        return -1;
    }

    if (qemu_opt_get(opts, "fd")) {
        snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
    } else {
        const char *ifname, *script, *downscript;

        ifname     = qemu_opt_get(opts, "ifname");
        script     = qemu_opt_get(opts, "script");
        downscript = qemu_opt_get(opts, "downscript");

        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
                 "ifname=%s,script=%s,downscript=%s",
                 ifname, script, downscript);

        if (strcmp(downscript, "no") != 0) {
            snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
            snprintf(s->down_script_arg, sizeof(s->down_script_arg), "%s", ifname);
        }
    }

    if (qemu_opt_get_bool(opts, "vhost", !!qemu_opt_get(opts, "vhostfd"))) {
        int vhostfd, r;
        if (qemu_opt_get(opts, "vhostfd")) {
            r = net_handle_fd_param(mon, qemu_opt_get(opts, "vhostfd"));
            if (r == -1) {
                return -1;
            }
            vhostfd = r;
        } else {
            vhostfd = -1;
        }
        s->vhost_net = vhost_net_init(&s->nc, vhostfd);
        if (!s->vhost_net) {
            error_report("vhost-net requested but could not be initialized");
            return -1;
        }
    } else if (qemu_opt_get(opts, "vhostfd")) {
        error_report("vhostfd= is not valid without vhost");
        return -1;
    }

    return 0;
}

VHostNetState *tap_get_vhost_net(VLANClientState *nc)
{
    TAPState *s = DO_UPCAST(TAPState, nc, nc);
    assert(nc->info->type == NET_CLIENT_TYPE_TAP);
    return s->vhost_net;
}