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
29
30 #include <sys/ioctl.h>
31 #include <sys/wait.h>
32 #include <sys/socket.h>
33 #include <net/if.h>
34
35 #include "net/eth.h"
36 #include "net/net.h"
37 #include "clients.h"
38 #include "monitor/monitor.h"
39 #include "system/system.h"
40 #include "qapi/error.h"
41 #include "qemu/cutils.h"
42 #include "qemu/error-report.h"
43 #include "qemu/main-loop.h"
44 #include "qemu/sockets.h"
45 #include "hw/virtio/vhost.h"
46
47 #include "net/tap.h"
48
49 #include "net/vhost_net.h"
50
51 static const int kernel_feature_bits[] = {
52 VIRTIO_F_NOTIFY_ON_EMPTY,
53 VIRTIO_RING_F_INDIRECT_DESC,
54 VIRTIO_RING_F_EVENT_IDX,
55 VIRTIO_NET_F_MRG_RXBUF,
56 VIRTIO_F_VERSION_1,
57 VIRTIO_NET_F_MTU,
58 VIRTIO_F_IOMMU_PLATFORM,
59 VIRTIO_F_RING_PACKED,
60 VIRTIO_F_RING_RESET,
61 VIRTIO_F_IN_ORDER,
62 VIRTIO_F_NOTIFICATION_DATA,
63 VIRTIO_NET_F_RSC_EXT,
64 VIRTIO_NET_F_HASH_REPORT,
65 VHOST_INVALID_FEATURE_BIT
66 };
67
68 typedef struct TAPState {
69 NetClientState nc;
70 int fd;
71 char down_script[1024];
72 char down_script_arg[128];
73 uint8_t buf[NET_BUFSIZE];
74 bool read_poll;
75 bool write_poll;
76 bool using_vnet_hdr;
77 bool has_ufo;
78 bool has_uso;
79 bool enabled;
80 VHostNetState *vhost_net;
81 unsigned host_vnet_hdr_len;
82 Notifier exit;
83 } TAPState;
84
85 static void launch_script(const char *setup_script, const char *ifname,
86 int fd, Error **errp);
87
88 static void tap_send(void *opaque);
89 static void tap_writable(void *opaque);
90
tap_update_fd_handler(TAPState * s)91 static void tap_update_fd_handler(TAPState *s)
92 {
93 qemu_set_fd_handler(s->fd,
94 s->read_poll && s->enabled ? tap_send : NULL,
95 s->write_poll && s->enabled ? tap_writable : NULL,
96 s);
97 }
98
tap_read_poll(TAPState * s,bool enable)99 static void tap_read_poll(TAPState *s, bool enable)
100 {
101 s->read_poll = enable;
102 tap_update_fd_handler(s);
103 }
104
tap_write_poll(TAPState * s,bool enable)105 static void tap_write_poll(TAPState *s, bool enable)
106 {
107 s->write_poll = enable;
108 tap_update_fd_handler(s);
109 }
110
tap_writable(void * opaque)111 static void tap_writable(void *opaque)
112 {
113 TAPState *s = opaque;
114
115 tap_write_poll(s, false);
116
117 qemu_flush_queued_packets(&s->nc);
118 }
119
tap_write_packet(TAPState * s,const struct iovec * iov,int iovcnt)120 static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
121 {
122 ssize_t len;
123
124 len = RETRY_ON_EINTR(writev(s->fd, iov, iovcnt));
125
126 if (len == -1 && errno == EAGAIN) {
127 tap_write_poll(s, true);
128 return 0;
129 }
130
131 return len;
132 }
133
tap_receive_iov(NetClientState * nc,const struct iovec * iov,int iovcnt)134 static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
135 int iovcnt)
136 {
137 TAPState *s = DO_UPCAST(TAPState, nc, nc);
138 const struct iovec *iovp = iov;
139 g_autofree struct iovec *iov_copy = NULL;
140 struct virtio_net_hdr hdr = { };
141
142 if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
143 iov_copy = g_new(struct iovec, iovcnt + 1);
144 iov_copy[0].iov_base = &hdr;
145 iov_copy[0].iov_len = s->host_vnet_hdr_len;
146 memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
147 iovp = iov_copy;
148 iovcnt++;
149 }
150
151 return tap_write_packet(s, iovp, iovcnt);
152 }
153
tap_receive(NetClientState * nc,const uint8_t * buf,size_t size)154 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
155 {
156 struct iovec iov = {
157 .iov_base = (void *)buf,
158 .iov_len = size
159 };
160
161 return tap_receive_iov(nc, &iov, 1);
162 }
163
164 #ifndef __sun__
tap_read_packet(int tapfd,uint8_t * buf,int maxlen)165 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
166 {
167 return read(tapfd, buf, maxlen);
168 }
169 #endif
170
tap_send_completed(NetClientState * nc,ssize_t len)171 static void tap_send_completed(NetClientState *nc, ssize_t len)
172 {
173 TAPState *s = DO_UPCAST(TAPState, nc, nc);
174 tap_read_poll(s, true);
175 }
176
tap_send(void * opaque)177 static void tap_send(void *opaque)
178 {
179 TAPState *s = opaque;
180 int size;
181 int packets = 0;
182
183 while (true) {
184 uint8_t *buf = s->buf;
185 uint8_t min_pkt[ETH_ZLEN];
186 size_t min_pktsz = sizeof(min_pkt);
187
188 size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
189 if (size <= 0) {
190 break;
191 }
192
193 if (s->host_vnet_hdr_len && size <= s->host_vnet_hdr_len) {
194 /* Invalid packet */
195 break;
196 }
197
198 if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
199 buf += s->host_vnet_hdr_len;
200 size -= s->host_vnet_hdr_len;
201 }
202
203 if (net_peer_needs_padding(&s->nc)) {
204 if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) {
205 buf = min_pkt;
206 size = min_pktsz;
207 }
208 }
209
210 size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
211 if (size == 0) {
212 tap_read_poll(s, false);
213 break;
214 } else if (size < 0) {
215 break;
216 }
217
218 /*
219 * When the host keeps receiving more packets while tap_send() is
220 * running we can hog the BQL. Limit the number of
221 * packets that are processed per tap_send() callback to prevent
222 * stalling the guest.
223 */
224 packets++;
225 if (packets >= 50) {
226 break;
227 }
228 }
229 }
230
tap_has_ufo(NetClientState * nc)231 static bool tap_has_ufo(NetClientState *nc)
232 {
233 TAPState *s = DO_UPCAST(TAPState, nc, nc);
234
235 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
236
237 return s->has_ufo;
238 }
239
tap_has_uso(NetClientState * nc)240 static bool tap_has_uso(NetClientState *nc)
241 {
242 TAPState *s = DO_UPCAST(TAPState, nc, nc);
243
244 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
245
246 return s->has_uso;
247 }
248
tap_has_vnet_hdr(NetClientState * nc)249 static bool tap_has_vnet_hdr(NetClientState *nc)
250 {
251 TAPState *s = DO_UPCAST(TAPState, nc, nc);
252
253 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
254
255 return !!s->host_vnet_hdr_len;
256 }
257
tap_has_vnet_hdr_len(NetClientState * nc,int len)258 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
259 {
260 return tap_has_vnet_hdr(nc);
261 }
262
tap_set_vnet_hdr_len(NetClientState * nc,int len)263 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
264 {
265 TAPState *s = DO_UPCAST(TAPState, nc, nc);
266
267 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
268
269 tap_fd_set_vnet_hdr_len(s->fd, len);
270 s->host_vnet_hdr_len = len;
271 s->using_vnet_hdr = true;
272 }
273
tap_set_vnet_le(NetClientState * nc,bool is_le)274 static int tap_set_vnet_le(NetClientState *nc, bool is_le)
275 {
276 TAPState *s = DO_UPCAST(TAPState, nc, nc);
277
278 return tap_fd_set_vnet_le(s->fd, is_le);
279 }
280
tap_set_vnet_be(NetClientState * nc,bool is_be)281 static int tap_set_vnet_be(NetClientState *nc, bool is_be)
282 {
283 TAPState *s = DO_UPCAST(TAPState, nc, nc);
284
285 return tap_fd_set_vnet_be(s->fd, is_be);
286 }
287
tap_set_offload(NetClientState * nc,int csum,int tso4,int tso6,int ecn,int ufo,int uso4,int uso6)288 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
289 int tso6, int ecn, int ufo, int uso4, int uso6)
290 {
291 TAPState *s = DO_UPCAST(TAPState, nc, nc);
292 if (s->fd < 0) {
293 return;
294 }
295
296 tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo, uso4, uso6);
297 }
298
tap_exit_notify(Notifier * notifier,void * data)299 static void tap_exit_notify(Notifier *notifier, void *data)
300 {
301 TAPState *s = container_of(notifier, TAPState, exit);
302 Error *err = NULL;
303
304 if (s->down_script[0]) {
305 launch_script(s->down_script, s->down_script_arg, s->fd, &err);
306 if (err) {
307 error_report_err(err);
308 }
309 }
310 }
311
tap_cleanup(NetClientState * nc)312 static void tap_cleanup(NetClientState *nc)
313 {
314 TAPState *s = DO_UPCAST(TAPState, nc, nc);
315
316 if (s->vhost_net) {
317 vhost_net_cleanup(s->vhost_net);
318 g_free(s->vhost_net);
319 s->vhost_net = NULL;
320 }
321
322 qemu_purge_queued_packets(nc);
323
324 tap_exit_notify(&s->exit, NULL);
325 qemu_remove_exit_notifier(&s->exit);
326
327 tap_read_poll(s, false);
328 tap_write_poll(s, false);
329 close(s->fd);
330 s->fd = -1;
331 }
332
tap_poll(NetClientState * nc,bool enable)333 static void tap_poll(NetClientState *nc, bool enable)
334 {
335 TAPState *s = DO_UPCAST(TAPState, nc, nc);
336 tap_read_poll(s, enable);
337 tap_write_poll(s, enable);
338 }
339
tap_set_steering_ebpf(NetClientState * nc,int prog_fd)340 static bool tap_set_steering_ebpf(NetClientState *nc, int prog_fd)
341 {
342 TAPState *s = DO_UPCAST(TAPState, nc, nc);
343 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
344
345 return tap_fd_set_steering_ebpf(s->fd, prog_fd) == 0;
346 }
347
tap_get_fd(NetClientState * nc)348 int tap_get_fd(NetClientState *nc)
349 {
350 TAPState *s = DO_UPCAST(TAPState, nc, nc);
351 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
352 return s->fd;
353 }
354
355 /*
356 * tap_get_vhost_net() can return NULL if a tap net-device backend is
357 * created with 'vhost=off' option, 'vhostforce=off' or no vhost or
358 * vhostforce or vhostfd options at all. Please see net_init_tap_one().
359 */
tap_get_vhost_net(NetClientState * nc)360 static VHostNetState *tap_get_vhost_net(NetClientState *nc)
361 {
362 TAPState *s = DO_UPCAST(TAPState, nc, nc);
363 assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
364 return s->vhost_net;
365 }
366
367 /* fd support */
368
369 static NetClientInfo net_tap_info = {
370 .type = NET_CLIENT_DRIVER_TAP,
371 .size = sizeof(TAPState),
372 .receive = tap_receive,
373 .receive_iov = tap_receive_iov,
374 .poll = tap_poll,
375 .cleanup = tap_cleanup,
376 .has_ufo = tap_has_ufo,
377 .has_uso = tap_has_uso,
378 .has_vnet_hdr = tap_has_vnet_hdr,
379 .has_vnet_hdr_len = tap_has_vnet_hdr_len,
380 .set_offload = tap_set_offload,
381 .set_vnet_hdr_len = tap_set_vnet_hdr_len,
382 .set_vnet_le = tap_set_vnet_le,
383 .set_vnet_be = tap_set_vnet_be,
384 .set_steering_ebpf = tap_set_steering_ebpf,
385 .get_vhost_net = tap_get_vhost_net,
386 };
387
net_tap_fd_init(NetClientState * peer,const char * model,const char * name,int fd,int vnet_hdr)388 static TAPState *net_tap_fd_init(NetClientState *peer,
389 const char *model,
390 const char *name,
391 int fd,
392 int vnet_hdr)
393 {
394 NetClientState *nc;
395 TAPState *s;
396
397 nc = qemu_new_net_client(&net_tap_info, peer, model, name);
398
399 s = DO_UPCAST(TAPState, nc, nc);
400
401 s->fd = fd;
402 s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
403 s->using_vnet_hdr = false;
404 s->has_ufo = tap_probe_has_ufo(s->fd);
405 s->has_uso = tap_probe_has_uso(s->fd);
406 s->enabled = true;
407 tap_set_offload(&s->nc, 0, 0, 0, 0, 0, 0, 0);
408 /*
409 * Make sure host header length is set correctly in tap:
410 * it might have been modified by another instance of qemu.
411 */
412 if (vnet_hdr) {
413 tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
414 }
415 tap_read_poll(s, true);
416 s->vhost_net = NULL;
417
418 s->exit.notify = tap_exit_notify;
419 qemu_add_exit_notifier(&s->exit);
420
421 return s;
422 }
423
close_all_fds_after_fork(int excluded_fd)424 static void close_all_fds_after_fork(int excluded_fd)
425 {
426 const int skip_fd[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO,
427 excluded_fd};
428 unsigned int nskip = ARRAY_SIZE(skip_fd);
429
430 /*
431 * skip_fd must be an ordered array of distinct fds, exclude
432 * excluded_fd if already included in the [STDIN_FILENO - STDERR_FILENO]
433 * range
434 */
435 if (excluded_fd <= STDERR_FILENO) {
436 nskip--;
437 }
438
439 qemu_close_all_open_fd(skip_fd, nskip);
440 }
441
launch_script(const char * setup_script,const char * ifname,int fd,Error ** errp)442 static void launch_script(const char *setup_script, const char *ifname,
443 int fd, Error **errp)
444 {
445 int pid, status;
446 char *args[3];
447 char **parg;
448
449 /* try to launch network script */
450 pid = fork();
451 if (pid < 0) {
452 error_setg_errno(errp, errno, "could not launch network script %s",
453 setup_script);
454 return;
455 }
456 if (pid == 0) {
457 close_all_fds_after_fork(fd);
458 parg = args;
459 *parg++ = (char *)setup_script;
460 *parg++ = (char *)ifname;
461 *parg = NULL;
462 execv(setup_script, args);
463 _exit(1);
464 } else {
465 while (waitpid(pid, &status, 0) != pid) {
466 /* loop */
467 }
468
469 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
470 return;
471 }
472 error_setg(errp, "network script %s failed with status %d",
473 setup_script, status);
474 }
475 }
476
recv_fd(int c)477 static int recv_fd(int c)
478 {
479 int fd;
480 uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
481 struct msghdr msg = {
482 .msg_control = msgbuf,
483 .msg_controllen = sizeof(msgbuf),
484 };
485 struct cmsghdr *cmsg;
486 struct iovec iov;
487 uint8_t req[1];
488 ssize_t len;
489
490 cmsg = CMSG_FIRSTHDR(&msg);
491 cmsg->cmsg_level = SOL_SOCKET;
492 cmsg->cmsg_type = SCM_RIGHTS;
493 cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
494 msg.msg_controllen = cmsg->cmsg_len;
495
496 iov.iov_base = req;
497 iov.iov_len = sizeof(req);
498
499 msg.msg_iov = &iov;
500 msg.msg_iovlen = 1;
501
502 len = recvmsg(c, &msg, 0);
503 if (len > 0) {
504 memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
505 return fd;
506 }
507
508 return len;
509 }
510
net_bridge_run_helper(const char * helper,const char * bridge,Error ** errp)511 static int net_bridge_run_helper(const char *helper, const char *bridge,
512 Error **errp)
513 {
514 sigset_t oldmask, mask;
515 g_autofree char *default_helper = NULL;
516 int pid, status;
517 char *args[5];
518 char **parg;
519 int sv[2];
520
521 sigemptyset(&mask);
522 sigaddset(&mask, SIGCHLD);
523 sigprocmask(SIG_BLOCK, &mask, &oldmask);
524
525 if (!helper) {
526 helper = default_helper = get_relocated_path(DEFAULT_BRIDGE_HELPER);
527 }
528
529 if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
530 error_setg_errno(errp, errno, "socketpair() failed");
531 return -1;
532 }
533
534 /* try to launch bridge helper */
535 pid = fork();
536 if (pid < 0) {
537 error_setg_errno(errp, errno, "Can't fork bridge helper");
538 return -1;
539 }
540 if (pid == 0) {
541 char *fd_buf = NULL;
542 char *br_buf = NULL;
543 char *helper_cmd = NULL;
544
545 close_all_fds_after_fork(sv[1]);
546 fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
547
548 if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
549 /* assume helper is a command */
550
551 if (strstr(helper, "--br=") == NULL) {
552 br_buf = g_strdup_printf("%s%s", "--br=", bridge);
553 }
554
555 helper_cmd = g_strdup_printf("%s %s %s %s", helper,
556 "--use-vnet", fd_buf, br_buf ? br_buf : "");
557
558 parg = args;
559 *parg++ = (char *)"sh";
560 *parg++ = (char *)"-c";
561 *parg++ = helper_cmd;
562 *parg++ = NULL;
563
564 execv("/bin/sh", args);
565 g_free(helper_cmd);
566 } else {
567 /* assume helper is just the executable path name */
568
569 br_buf = g_strdup_printf("%s%s", "--br=", bridge);
570
571 parg = args;
572 *parg++ = (char *)helper;
573 *parg++ = (char *)"--use-vnet";
574 *parg++ = fd_buf;
575 *parg++ = br_buf;
576 *parg++ = NULL;
577
578 execv(helper, args);
579 }
580 g_free(fd_buf);
581 g_free(br_buf);
582 _exit(1);
583
584 } else {
585 int fd;
586 int saved_errno;
587
588 close(sv[1]);
589
590 fd = RETRY_ON_EINTR(recv_fd(sv[0]));
591 saved_errno = errno;
592
593 close(sv[0]);
594
595 while (waitpid(pid, &status, 0) != pid) {
596 /* loop */
597 }
598 sigprocmask(SIG_SETMASK, &oldmask, NULL);
599 if (fd < 0) {
600 error_setg_errno(errp, saved_errno,
601 "failed to recv file descriptor");
602 return -1;
603 }
604 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
605 error_setg(errp, "bridge helper failed");
606 return -1;
607 }
608 return fd;
609 }
610 }
611
net_init_bridge(const Netdev * netdev,const char * name,NetClientState * peer,Error ** errp)612 int net_init_bridge(const Netdev *netdev, const char *name,
613 NetClientState *peer, Error **errp)
614 {
615 const NetdevBridgeOptions *bridge;
616 const char *helper, *br;
617 TAPState *s;
618 int fd, vnet_hdr;
619
620 assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
621 bridge = &netdev->u.bridge;
622 helper = bridge->helper;
623 br = bridge->br ?: DEFAULT_BRIDGE_INTERFACE;
624
625 fd = net_bridge_run_helper(helper, br, errp);
626 if (fd == -1) {
627 return -1;
628 }
629
630 if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
631 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
632 return -1;
633 }
634 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
635 if (vnet_hdr < 0) {
636 close(fd);
637 return -1;
638 }
639 s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
640
641 qemu_set_info_str(&s->nc, "helper=%s,br=%s", helper, br);
642
643 return 0;
644 }
645
net_tap_init(const NetdevTapOptions * tap,int * vnet_hdr,const char * setup_script,char * ifname,size_t ifname_sz,int mq_required,Error ** errp)646 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
647 const char *setup_script, char *ifname,
648 size_t ifname_sz, int mq_required, Error **errp)
649 {
650 Error *err = NULL;
651 int fd, vnet_hdr_required;
652
653 if (tap->has_vnet_hdr) {
654 *vnet_hdr = tap->vnet_hdr;
655 vnet_hdr_required = *vnet_hdr;
656 } else {
657 *vnet_hdr = 1;
658 vnet_hdr_required = 0;
659 }
660
661 fd = RETRY_ON_EINTR(tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
662 mq_required, errp));
663 if (fd < 0) {
664 return -1;
665 }
666
667 if (setup_script &&
668 setup_script[0] != '\0' &&
669 strcmp(setup_script, "no") != 0) {
670 launch_script(setup_script, ifname, fd, &err);
671 if (err) {
672 error_propagate(errp, err);
673 close(fd);
674 return -1;
675 }
676 }
677
678 return fd;
679 }
680
681 #define MAX_TAP_QUEUES 1024
682
net_init_tap_one(const NetdevTapOptions * tap,NetClientState * peer,const char * model,const char * name,const char * ifname,const char * script,const char * downscript,const char * vhostfdname,int vnet_hdr,int fd,Error ** errp)683 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
684 const char *model, const char *name,
685 const char *ifname, const char *script,
686 const char *downscript, const char *vhostfdname,
687 int vnet_hdr, int fd, Error **errp)
688 {
689 Error *err = NULL;
690 TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
691 int vhostfd;
692
693 tap_set_sndbuf(s->fd, tap, &err);
694 if (err) {
695 error_propagate(errp, err);
696 goto failed;
697 }
698
699 if (tap->fd || tap->fds) {
700 qemu_set_info_str(&s->nc, "fd=%d", fd);
701 } else if (tap->helper) {
702 qemu_set_info_str(&s->nc, "helper=%s", tap->helper);
703 } else {
704 qemu_set_info_str(&s->nc, "ifname=%s,script=%s,downscript=%s", ifname,
705 script, downscript);
706
707 if (strcmp(downscript, "no") != 0) {
708 snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
709 snprintf(s->down_script_arg, sizeof(s->down_script_arg),
710 "%s", ifname);
711 }
712 }
713
714 if (tap->has_vhost ? tap->vhost :
715 vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
716 VhostNetOptions options;
717
718 options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
719 options.net_backend = &s->nc;
720 if (tap->has_poll_us) {
721 options.busyloop_timeout = tap->poll_us;
722 } else {
723 options.busyloop_timeout = 0;
724 }
725
726 if (vhostfdname) {
727 vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
728 if (vhostfd == -1) {
729 error_propagate(errp, err);
730 goto failed;
731 }
732 if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
733 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
734 name, fd);
735 goto failed;
736 }
737 } else {
738 vhostfd = open("/dev/vhost-net", O_RDWR);
739 if (vhostfd < 0) {
740 error_setg_errno(errp, errno,
741 "tap: open vhost char device failed");
742 goto failed;
743 }
744 if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
745 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
746 goto failed;
747 }
748 }
749 options.opaque = (void *)(uintptr_t)vhostfd;
750 options.nvqs = 2;
751 options.feature_bits = kernel_feature_bits;
752 options.get_acked_features = NULL;
753 options.save_acked_features = NULL;
754 options.max_tx_queue_size = 0;
755 options.is_vhost_user = false;
756
757 s->vhost_net = vhost_net_init(&options);
758 if (!s->vhost_net) {
759 error_setg(errp,
760 "vhost-net requested but could not be initialized");
761 goto failed;
762 }
763 } else if (vhostfdname) {
764 error_setg(errp, "vhostfd(s)= is not valid without vhost");
765 goto failed;
766 }
767
768 return;
769
770 failed:
771 qemu_del_net_client(&s->nc);
772 }
773
get_fds(char * str,char * fds[],int max)774 static int get_fds(char *str, char *fds[], int max)
775 {
776 char *ptr = str, *this;
777 size_t len = strlen(str);
778 int i = 0;
779
780 while (i < max && ptr < str + len) {
781 this = strchr(ptr, ':');
782
783 if (this == NULL) {
784 fds[i] = g_strdup(ptr);
785 } else {
786 fds[i] = g_strndup(ptr, this - ptr);
787 }
788
789 i++;
790 if (this == NULL) {
791 break;
792 } else {
793 ptr = this + 1;
794 }
795 }
796
797 return i;
798 }
799
net_init_tap(const Netdev * netdev,const char * name,NetClientState * peer,Error ** errp)800 int net_init_tap(const Netdev *netdev, const char *name,
801 NetClientState *peer, Error **errp)
802 {
803 const NetdevTapOptions *tap;
804 int fd, vnet_hdr = 0, i = 0, queues;
805 /* for the no-fd, no-helper case */
806 const char *script;
807 const char *downscript;
808 Error *err = NULL;
809 const char *vhostfdname;
810 char ifname[128];
811 int ret = 0;
812
813 assert(netdev->type == NET_CLIENT_DRIVER_TAP);
814 tap = &netdev->u.tap;
815 queues = tap->has_queues ? tap->queues : 1;
816 vhostfdname = tap->vhostfd;
817 script = tap->script;
818 downscript = tap->downscript;
819
820 /* QEMU hubs do not support multiqueue tap, in this case peer is set.
821 * For -netdev, peer is always NULL. */
822 if (peer && (tap->has_queues || tap->fds || tap->vhostfds)) {
823 error_setg(errp, "Multiqueue tap cannot be used with hubs");
824 return -1;
825 }
826
827 if (tap->fd) {
828 if (tap->ifname || tap->script || tap->downscript ||
829 tap->has_vnet_hdr || tap->helper || tap->has_queues ||
830 tap->fds || tap->vhostfds) {
831 error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
832 "helper=, queues=, fds=, and vhostfds= "
833 "are invalid with fd=");
834 return -1;
835 }
836
837 fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
838 if (fd == -1) {
839 return -1;
840 }
841
842 if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
843 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
844 name, fd);
845 close(fd);
846 return -1;
847 }
848
849 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
850 if (vnet_hdr < 0) {
851 close(fd);
852 return -1;
853 }
854
855 net_init_tap_one(tap, peer, "tap", name, NULL,
856 script, downscript,
857 vhostfdname, vnet_hdr, fd, &err);
858 if (err) {
859 error_propagate(errp, err);
860 close(fd);
861 return -1;
862 }
863 } else if (tap->fds) {
864 char **fds;
865 char **vhost_fds;
866 int nfds = 0, nvhosts = 0;
867
868 if (tap->ifname || tap->script || tap->downscript ||
869 tap->has_vnet_hdr || tap->helper || tap->has_queues ||
870 tap->vhostfd) {
871 error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
872 "helper=, queues=, and vhostfd= "
873 "are invalid with fds=");
874 return -1;
875 }
876
877 fds = g_new0(char *, MAX_TAP_QUEUES);
878 vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
879
880 nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
881 if (tap->vhostfds) {
882 nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
883 if (nfds != nvhosts) {
884 error_setg(errp, "The number of fds passed does not match "
885 "the number of vhostfds passed");
886 ret = -1;
887 goto free_fail;
888 }
889 }
890
891 for (i = 0; i < nfds; i++) {
892 fd = monitor_fd_param(monitor_cur(), fds[i], errp);
893 if (fd == -1) {
894 ret = -1;
895 goto free_fail;
896 }
897
898 if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
899 ret = -1;
900 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
901 name, fd);
902 goto free_fail;
903 }
904
905 if (i == 0) {
906 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
907 if (vnet_hdr < 0) {
908 ret = -1;
909 goto free_fail;
910 }
911 } else if (vnet_hdr != tap_probe_vnet_hdr(fd, NULL)) {
912 error_setg(errp,
913 "vnet_hdr not consistent across given tap fds");
914 ret = -1;
915 goto free_fail;
916 }
917
918 net_init_tap_one(tap, peer, "tap", name, ifname,
919 script, downscript,
920 tap->vhostfds ? vhost_fds[i] : NULL,
921 vnet_hdr, fd, &err);
922 if (err) {
923 error_propagate(errp, err);
924 ret = -1;
925 goto free_fail;
926 }
927 }
928
929 free_fail:
930 for (i = 0; i < nvhosts; i++) {
931 g_free(vhost_fds[i]);
932 }
933 for (i = 0; i < nfds; i++) {
934 g_free(fds[i]);
935 }
936 g_free(fds);
937 g_free(vhost_fds);
938 return ret;
939 } else if (tap->helper) {
940 if (tap->ifname || tap->script || tap->downscript ||
941 tap->has_vnet_hdr || tap->has_queues || tap->vhostfds) {
942 error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
943 "queues=, and vhostfds= are invalid with helper=");
944 return -1;
945 }
946
947 fd = net_bridge_run_helper(tap->helper,
948 tap->br ?: DEFAULT_BRIDGE_INTERFACE,
949 errp);
950 if (fd == -1) {
951 return -1;
952 }
953
954 if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
955 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
956 return -1;
957 }
958 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
959 if (vnet_hdr < 0) {
960 close(fd);
961 return -1;
962 }
963
964 net_init_tap_one(tap, peer, "bridge", name, ifname,
965 script, downscript, vhostfdname,
966 vnet_hdr, fd, &err);
967 if (err) {
968 error_propagate(errp, err);
969 close(fd);
970 return -1;
971 }
972 } else {
973 g_autofree char *default_script = NULL;
974 g_autofree char *default_downscript = NULL;
975 if (tap->vhostfds) {
976 error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
977 return -1;
978 }
979
980 if (!script) {
981 script = default_script = get_relocated_path(DEFAULT_NETWORK_SCRIPT);
982 }
983 if (!downscript) {
984 downscript = default_downscript =
985 get_relocated_path(DEFAULT_NETWORK_DOWN_SCRIPT);
986 }
987
988 if (tap->ifname) {
989 pstrcpy(ifname, sizeof ifname, tap->ifname);
990 } else {
991 ifname[0] = '\0';
992 }
993
994 for (i = 0; i < queues; i++) {
995 fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
996 ifname, sizeof ifname, queues > 1, errp);
997 if (fd == -1) {
998 return -1;
999 }
1000
1001 if (queues > 1 && i == 0 && !tap->ifname) {
1002 if (tap_fd_get_ifname(fd, ifname)) {
1003 error_setg(errp, "Fail to get ifname");
1004 close(fd);
1005 return -1;
1006 }
1007 }
1008
1009 net_init_tap_one(tap, peer, "tap", name, ifname,
1010 i >= 1 ? "no" : script,
1011 i >= 1 ? "no" : downscript,
1012 vhostfdname, vnet_hdr, fd, &err);
1013 if (err) {
1014 error_propagate(errp, err);
1015 close(fd);
1016 return -1;
1017 }
1018 }
1019 }
1020
1021 return 0;
1022 }
1023
tap_enable(NetClientState * nc)1024 int tap_enable(NetClientState *nc)
1025 {
1026 TAPState *s = DO_UPCAST(TAPState, nc, nc);
1027 int ret;
1028
1029 if (s->enabled) {
1030 return 0;
1031 } else {
1032 ret = tap_fd_enable(s->fd);
1033 if (ret == 0) {
1034 s->enabled = true;
1035 tap_update_fd_handler(s);
1036 }
1037 return ret;
1038 }
1039 }
1040
tap_disable(NetClientState * nc)1041 int tap_disable(NetClientState *nc)
1042 {
1043 TAPState *s = DO_UPCAST(TAPState, nc, nc);
1044 int ret;
1045
1046 if (s->enabled == 0) {
1047 return 0;
1048 } else {
1049 ret = tap_fd_disable(s->fd);
1050 if (ret == 0) {
1051 qemu_purge_queued_packets(nc);
1052 s->enabled = false;
1053 tap_update_fd_handler(s);
1054 }
1055 return ret;
1056 }
1057 }
1058