qdev: remove baked in notion of aliases (v2)
[qemu.git] / net / tap.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 "net/tap.h"
27
28 #include "config-host.h"
29
30 #include <sys/ioctl.h>
31 #include <sys/stat.h>
32 #include <sys/wait.h>
33 #include <sys/socket.h>
34 #include <net/if.h>
35
36 #include "net.h"
37 #include "sysemu.h"
38 #include "qemu-char.h"
39 #include "qemu-common.h"
40 #include "qemu-error.h"
41
42 #include "net/tap-linux.h"
43
44 #include "hw/vhost_net.h"
45
46 /* Maximum GSO packet size (64k) plus plenty of room for
47 * the ethernet and virtio_net headers
48 */
49 #define TAP_BUFSIZE (4096 + 65536)
50
51 typedef struct TAPState {
52 VLANClientState nc;
53 int fd;
54 char down_script[1024];
55 char down_script_arg[128];
56 uint8_t buf[TAP_BUFSIZE];
57 unsigned int read_poll : 1;
58 unsigned int write_poll : 1;
59 unsigned int using_vnet_hdr : 1;
60 unsigned int has_ufo: 1;
61 VHostNetState *vhost_net;
62 unsigned host_vnet_hdr_len;
63 } TAPState;
64
65 static int launch_script(const char *setup_script, const char *ifname, int fd);
66
67 static int tap_can_send(void *opaque);
68 static void tap_send(void *opaque);
69 static void tap_writable(void *opaque);
70
71 static void tap_update_fd_handler(TAPState *s)
72 {
73 qemu_set_fd_handler2(s->fd,
74 s->read_poll ? tap_can_send : NULL,
75 s->read_poll ? tap_send : NULL,
76 s->write_poll ? tap_writable : NULL,
77 s);
78 }
79
80 static void tap_read_poll(TAPState *s, int enable)
81 {
82 s->read_poll = !!enable;
83 tap_update_fd_handler(s);
84 }
85
86 static void tap_write_poll(TAPState *s, int enable)
87 {
88 s->write_poll = !!enable;
89 tap_update_fd_handler(s);
90 }
91
92 static void tap_writable(void *opaque)
93 {
94 TAPState *s = opaque;
95
96 tap_write_poll(s, 0);
97
98 qemu_flush_queued_packets(&s->nc);
99 }
100
101 static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
102 {
103 ssize_t len;
104
105 do {
106 len = writev(s->fd, iov, iovcnt);
107 } while (len == -1 && errno == EINTR);
108
109 if (len == -1 && errno == EAGAIN) {
110 tap_write_poll(s, 1);
111 return 0;
112 }
113
114 return len;
115 }
116
117 static ssize_t tap_receive_iov(VLANClientState *nc, const struct iovec *iov,
118 int iovcnt)
119 {
120 TAPState *s = DO_UPCAST(TAPState, nc, nc);
121 const struct iovec *iovp = iov;
122 struct iovec iov_copy[iovcnt + 1];
123 struct virtio_net_hdr_mrg_rxbuf hdr = { };
124
125 if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
126 iov_copy[0].iov_base = &hdr;
127 iov_copy[0].iov_len = s->host_vnet_hdr_len;
128 memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
129 iovp = iov_copy;
130 iovcnt++;
131 }
132
133 return tap_write_packet(s, iovp, iovcnt);
134 }
135
136 static ssize_t tap_receive_raw(VLANClientState *nc, const uint8_t *buf, size_t size)
137 {
138 TAPState *s = DO_UPCAST(TAPState, nc, nc);
139 struct iovec iov[2];
140 int iovcnt = 0;
141 struct virtio_net_hdr_mrg_rxbuf hdr = { };
142
143 if (s->host_vnet_hdr_len) {
144 iov[iovcnt].iov_base = &hdr;
145 iov[iovcnt].iov_len = s->host_vnet_hdr_len;
146 iovcnt++;
147 }
148
149 iov[iovcnt].iov_base = (char *)buf;
150 iov[iovcnt].iov_len = size;
151 iovcnt++;
152
153 return tap_write_packet(s, iov, iovcnt);
154 }
155
156 static ssize_t tap_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
157 {
158 TAPState *s = DO_UPCAST(TAPState, nc, nc);
159 struct iovec iov[1];
160
161 if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
162 return tap_receive_raw(nc, buf, size);
163 }
164
165 iov[0].iov_base = (char *)buf;
166 iov[0].iov_len = size;
167
168 return tap_write_packet(s, iov, 1);
169 }
170
171 static int tap_can_send(void *opaque)
172 {
173 TAPState *s = opaque;
174
175 return qemu_can_send_packet(&s->nc);
176 }
177
178 #ifndef __sun__
179 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
180 {
181 return read(tapfd, buf, maxlen);
182 }
183 #endif
184
185 static void tap_send_completed(VLANClientState *nc, ssize_t len)
186 {
187 TAPState *s = DO_UPCAST(TAPState, nc, nc);
188 tap_read_poll(s, 1);
189 }
190
191 static void tap_send(void *opaque)
192 {
193 TAPState *s = opaque;
194 int size;
195
196 do {
197 uint8_t *buf = s->buf;
198
199 size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
200 if (size <= 0) {
201 break;
202 }
203
204 if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
205 buf += s->host_vnet_hdr_len;
206 size -= s->host_vnet_hdr_len;
207 }
208
209 size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
210 if (size == 0) {
211 tap_read_poll(s, 0);
212 }
213 } while (size > 0 && qemu_can_send_packet(&s->nc));
214 }
215
216 int tap_has_ufo(VLANClientState *nc)
217 {
218 TAPState *s = DO_UPCAST(TAPState, nc, nc);
219
220 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
221
222 return s->has_ufo;
223 }
224
225 int tap_has_vnet_hdr(VLANClientState *nc)
226 {
227 TAPState *s = DO_UPCAST(TAPState, nc, nc);
228
229 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
230
231 return !!s->host_vnet_hdr_len;
232 }
233
234 int tap_has_vnet_hdr_len(VLANClientState *nc, int len)
235 {
236 TAPState *s = DO_UPCAST(TAPState, nc, nc);
237
238 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
239
240 return tap_probe_vnet_hdr_len(s->fd, len);
241 }
242
243 void tap_set_vnet_hdr_len(VLANClientState *nc, int len)
244 {
245 TAPState *s = DO_UPCAST(TAPState, nc, nc);
246
247 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
248 assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
249 len == sizeof(struct virtio_net_hdr));
250
251 tap_fd_set_vnet_hdr_len(s->fd, len);
252 s->host_vnet_hdr_len = len;
253 }
254
255 void tap_using_vnet_hdr(VLANClientState *nc, int using_vnet_hdr)
256 {
257 TAPState *s = DO_UPCAST(TAPState, nc, nc);
258
259 using_vnet_hdr = using_vnet_hdr != 0;
260
261 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
262 assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
263
264 s->using_vnet_hdr = using_vnet_hdr;
265 }
266
267 void tap_set_offload(VLANClientState *nc, int csum, int tso4,
268 int tso6, int ecn, int ufo)
269 {
270 TAPState *s = DO_UPCAST(TAPState, nc, nc);
271 if (s->fd < 0) {
272 return;
273 }
274
275 tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
276 }
277
278 static void tap_cleanup(VLANClientState *nc)
279 {
280 TAPState *s = DO_UPCAST(TAPState, nc, nc);
281
282 if (s->vhost_net) {
283 vhost_net_cleanup(s->vhost_net);
284 s->vhost_net = NULL;
285 }
286
287 qemu_purge_queued_packets(nc);
288
289 if (s->down_script[0])
290 launch_script(s->down_script, s->down_script_arg, s->fd);
291
292 tap_read_poll(s, 0);
293 tap_write_poll(s, 0);
294 close(s->fd);
295 s->fd = -1;
296 }
297
298 static void tap_poll(VLANClientState *nc, bool enable)
299 {
300 TAPState *s = DO_UPCAST(TAPState, nc, nc);
301 tap_read_poll(s, enable);
302 tap_write_poll(s, enable);
303 }
304
305 int tap_get_fd(VLANClientState *nc)
306 {
307 TAPState *s = DO_UPCAST(TAPState, nc, nc);
308 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
309 return s->fd;
310 }
311
312 /* fd support */
313
314 static NetClientInfo net_tap_info = {
315 .type = NET_CLIENT_TYPE_TAP,
316 .size = sizeof(TAPState),
317 .receive = tap_receive,
318 .receive_raw = tap_receive_raw,
319 .receive_iov = tap_receive_iov,
320 .poll = tap_poll,
321 .cleanup = tap_cleanup,
322 };
323
324 static TAPState *net_tap_fd_init(VLANState *vlan,
325 const char *model,
326 const char *name,
327 int fd,
328 int vnet_hdr)
329 {
330 VLANClientState *nc;
331 TAPState *s;
332
333 nc = qemu_new_net_client(&net_tap_info, vlan, NULL, model, name);
334
335 s = DO_UPCAST(TAPState, nc, nc);
336
337 s->fd = fd;
338 s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
339 s->using_vnet_hdr = 0;
340 s->has_ufo = tap_probe_has_ufo(s->fd);
341 tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
342 tap_read_poll(s, 1);
343 s->vhost_net = NULL;
344 return s;
345 }
346
347 static int launch_script(const char *setup_script, const char *ifname, int fd)
348 {
349 int pid, status;
350 char *args[3];
351 char **parg;
352
353 /* try to launch network script */
354 pid = fork();
355 if (pid == 0) {
356 int open_max = sysconf(_SC_OPEN_MAX), i;
357
358 for (i = 0; i < open_max; i++) {
359 if (i != STDIN_FILENO &&
360 i != STDOUT_FILENO &&
361 i != STDERR_FILENO &&
362 i != fd) {
363 close(i);
364 }
365 }
366 parg = args;
367 *parg++ = (char *)setup_script;
368 *parg++ = (char *)ifname;
369 *parg = NULL;
370 execv(setup_script, args);
371 _exit(1);
372 } else if (pid > 0) {
373 while (waitpid(pid, &status, 0) != pid) {
374 /* loop */
375 }
376
377 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
378 return 0;
379 }
380 }
381 fprintf(stderr, "%s: could not launch network script\n", setup_script);
382 return -1;
383 }
384
385 static int recv_fd(int c)
386 {
387 int fd;
388 uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
389 struct msghdr msg = {
390 .msg_control = msgbuf,
391 .msg_controllen = sizeof(msgbuf),
392 };
393 struct cmsghdr *cmsg;
394 struct iovec iov;
395 uint8_t req[1];
396 ssize_t len;
397
398 cmsg = CMSG_FIRSTHDR(&msg);
399 cmsg->cmsg_level = SOL_SOCKET;
400 cmsg->cmsg_type = SCM_RIGHTS;
401 cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
402 msg.msg_controllen = cmsg->cmsg_len;
403
404 iov.iov_base = req;
405 iov.iov_len = sizeof(req);
406
407 msg.msg_iov = &iov;
408 msg.msg_iovlen = 1;
409
410 len = recvmsg(c, &msg, 0);
411 if (len > 0) {
412 memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
413 return fd;
414 }
415
416 return len;
417 }
418
419 static int net_bridge_run_helper(const char *helper, const char *bridge)
420 {
421 sigset_t oldmask, mask;
422 int pid, status;
423 char *args[5];
424 char **parg;
425 int sv[2];
426
427 sigemptyset(&mask);
428 sigaddset(&mask, SIGCHLD);
429 sigprocmask(SIG_BLOCK, &mask, &oldmask);
430
431 if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
432 return -1;
433 }
434
435 /* try to launch bridge helper */
436 pid = fork();
437 if (pid == 0) {
438 int open_max = sysconf(_SC_OPEN_MAX), i;
439 char fd_buf[6+10];
440 char br_buf[6+IFNAMSIZ] = {0};
441 char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
442
443 for (i = 0; i < open_max; i++) {
444 if (i != STDIN_FILENO &&
445 i != STDOUT_FILENO &&
446 i != STDERR_FILENO &&
447 i != sv[1]) {
448 close(i);
449 }
450 }
451
452 snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
453
454 if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
455 /* assume helper is a command */
456
457 if (strstr(helper, "--br=") == NULL) {
458 snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
459 }
460
461 snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
462 helper, "--use-vnet", fd_buf, br_buf);
463
464 parg = args;
465 *parg++ = (char *)"sh";
466 *parg++ = (char *)"-c";
467 *parg++ = helper_cmd;
468 *parg++ = NULL;
469
470 execv("/bin/sh", args);
471 } else {
472 /* assume helper is just the executable path name */
473
474 snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
475
476 parg = args;
477 *parg++ = (char *)helper;
478 *parg++ = (char *)"--use-vnet";
479 *parg++ = fd_buf;
480 *parg++ = br_buf;
481 *parg++ = NULL;
482
483 execv(helper, args);
484 }
485 _exit(1);
486
487 } else if (pid > 0) {
488 int fd;
489
490 close(sv[1]);
491
492 do {
493 fd = recv_fd(sv[0]);
494 } while (fd == -1 && errno == EINTR);
495
496 close(sv[0]);
497
498 while (waitpid(pid, &status, 0) != pid) {
499 /* loop */
500 }
501 sigprocmask(SIG_SETMASK, &oldmask, NULL);
502 if (fd < 0) {
503 fprintf(stderr, "failed to recv file descriptor\n");
504 return -1;
505 }
506
507 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
508 return fd;
509 }
510 }
511 fprintf(stderr, "failed to launch bridge helper\n");
512 return -1;
513 }
514
515 int net_init_bridge(QemuOpts *opts, Monitor *mon, const char *name,
516 VLANState *vlan)
517 {
518 TAPState *s;
519 int fd, vnet_hdr;
520
521 if (!qemu_opt_get(opts, "br")) {
522 qemu_opt_set(opts, "br", DEFAULT_BRIDGE_INTERFACE);
523 }
524 if (!qemu_opt_get(opts, "helper")) {
525 qemu_opt_set(opts, "helper", DEFAULT_BRIDGE_HELPER);
526 }
527
528 fd = net_bridge_run_helper(qemu_opt_get(opts, "helper"),
529 qemu_opt_get(opts, "br"));
530 if (fd == -1) {
531 return -1;
532 }
533
534 fcntl(fd, F_SETFL, O_NONBLOCK);
535
536 vnet_hdr = tap_probe_vnet_hdr(fd);
537
538 s = net_tap_fd_init(vlan, "bridge", name, fd, vnet_hdr);
539 if (!s) {
540 close(fd);
541 return -1;
542 }
543
544 snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s",
545 qemu_opt_get(opts, "helper"), qemu_opt_get(opts, "br"));
546
547 return 0;
548 }
549
550 static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
551 {
552 int fd, vnet_hdr_required;
553 char ifname[128] = {0,};
554 const char *setup_script;
555
556 if (qemu_opt_get(opts, "ifname")) {
557 pstrcpy(ifname, sizeof(ifname), qemu_opt_get(opts, "ifname"));
558 }
559
560 *vnet_hdr = qemu_opt_get_bool(opts, "vnet_hdr", 1);
561 if (qemu_opt_get(opts, "vnet_hdr")) {
562 vnet_hdr_required = *vnet_hdr;
563 } else {
564 vnet_hdr_required = 0;
565 }
566
567 TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr, vnet_hdr_required));
568 if (fd < 0) {
569 return -1;
570 }
571
572 setup_script = qemu_opt_get(opts, "script");
573 if (setup_script &&
574 setup_script[0] != '\0' &&
575 strcmp(setup_script, "no") != 0 &&
576 launch_script(setup_script, ifname, fd)) {
577 close(fd);
578 return -1;
579 }
580
581 qemu_opt_set(opts, "ifname", ifname);
582
583 return fd;
584 }
585
586 int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan)
587 {
588 TAPState *s;
589 int fd, vnet_hdr = 0;
590 const char *model;
591
592 if (qemu_opt_get(opts, "fd")) {
593 if (qemu_opt_get(opts, "ifname") ||
594 qemu_opt_get(opts, "script") ||
595 qemu_opt_get(opts, "downscript") ||
596 qemu_opt_get(opts, "vnet_hdr") ||
597 qemu_opt_get(opts, "helper")) {
598 error_report("ifname=, script=, downscript=, vnet_hdr=, "
599 "and helper= are invalid with fd=");
600 return -1;
601 }
602
603 fd = net_handle_fd_param(mon, qemu_opt_get(opts, "fd"));
604 if (fd == -1) {
605 return -1;
606 }
607
608 fcntl(fd, F_SETFL, O_NONBLOCK);
609
610 vnet_hdr = tap_probe_vnet_hdr(fd);
611
612 model = "tap";
613
614 } else if (qemu_opt_get(opts, "helper")) {
615 if (qemu_opt_get(opts, "ifname") ||
616 qemu_opt_get(opts, "script") ||
617 qemu_opt_get(opts, "downscript") ||
618 qemu_opt_get(opts, "vnet_hdr")) {
619 error_report("ifname=, script=, downscript=, and vnet_hdr= "
620 "are invalid with helper=");
621 return -1;
622 }
623
624 fd = net_bridge_run_helper(qemu_opt_get(opts, "helper"),
625 DEFAULT_BRIDGE_INTERFACE);
626 if (fd == -1) {
627 return -1;
628 }
629
630 fcntl(fd, F_SETFL, O_NONBLOCK);
631
632 vnet_hdr = tap_probe_vnet_hdr(fd);
633
634 model = "bridge";
635
636 } else {
637 if (!qemu_opt_get(opts, "script")) {
638 qemu_opt_set(opts, "script", DEFAULT_NETWORK_SCRIPT);
639 }
640
641 if (!qemu_opt_get(opts, "downscript")) {
642 qemu_opt_set(opts, "downscript", DEFAULT_NETWORK_DOWN_SCRIPT);
643 }
644
645 fd = net_tap_init(opts, &vnet_hdr);
646 if (fd == -1) {
647 return -1;
648 }
649
650 model = "tap";
651 }
652
653 s = net_tap_fd_init(vlan, model, name, fd, vnet_hdr);
654 if (!s) {
655 close(fd);
656 return -1;
657 }
658
659 if (tap_set_sndbuf(s->fd, opts) < 0) {
660 return -1;
661 }
662
663 if (qemu_opt_get(opts, "fd")) {
664 snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
665 } else if (qemu_opt_get(opts, "helper")) {
666 snprintf(s->nc.info_str, sizeof(s->nc.info_str),
667 "helper=%s", qemu_opt_get(opts, "helper"));
668 } else {
669 const char *ifname, *script, *downscript;
670
671 ifname = qemu_opt_get(opts, "ifname");
672 script = qemu_opt_get(opts, "script");
673 downscript = qemu_opt_get(opts, "downscript");
674
675 snprintf(s->nc.info_str, sizeof(s->nc.info_str),
676 "ifname=%s,script=%s,downscript=%s",
677 ifname, script, downscript);
678
679 if (strcmp(downscript, "no") != 0) {
680 snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
681 snprintf(s->down_script_arg, sizeof(s->down_script_arg), "%s", ifname);
682 }
683 }
684
685 if (qemu_opt_get_bool(opts, "vhost", !!qemu_opt_get(opts, "vhostfd") ||
686 qemu_opt_get_bool(opts, "vhostforce", false))) {
687 int vhostfd, r;
688 bool force = qemu_opt_get_bool(opts, "vhostforce", false);
689 if (qemu_opt_get(opts, "vhostfd")) {
690 r = net_handle_fd_param(mon, qemu_opt_get(opts, "vhostfd"));
691 if (r == -1) {
692 return -1;
693 }
694 vhostfd = r;
695 } else {
696 vhostfd = -1;
697 }
698 s->vhost_net = vhost_net_init(&s->nc, vhostfd, force);
699 if (!s->vhost_net) {
700 error_report("vhost-net requested but could not be initialized");
701 return -1;
702 }
703 } else if (qemu_opt_get(opts, "vhostfd")) {
704 error_report("vhostfd= is not valid without vhost");
705 return -1;
706 }
707
708 return 0;
709 }
710
711 VHostNetState *tap_get_vhost_net(VLANClientState *nc)
712 {
713 TAPState *s = DO_UPCAST(TAPState, nc, nc);
714 assert(nc->info->type == NET_CLIENT_TYPE_TAP);
715 return s->vhost_net;
716 }