xref: /openbmc/qemu/net/net.c (revision 91bfcdb0)
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include "config-host.h"
25 
26 #include "net/net.h"
27 #include "clients.h"
28 #include "hub.h"
29 #include "net/slirp.h"
30 #include "net/eth.h"
31 #include "util.h"
32 
33 #include "monitor/monitor.h"
34 #include "qemu-common.h"
35 #include "qapi/qmp/qerror.h"
36 #include "qemu/error-report.h"
37 #include "qemu/sockets.h"
38 #include "qemu/config-file.h"
39 #include "qmp-commands.h"
40 #include "hw/qdev.h"
41 #include "qemu/iov.h"
42 #include "qemu/main-loop.h"
43 #include "qapi-visit.h"
44 #include "qapi/opts-visitor.h"
45 #include "qapi/dealloc-visitor.h"
46 #include "sysemu/sysemu.h"
47 #include "net/filter.h"
48 
49 /* Net bridge is currently not supported for W32. */
50 #if !defined(_WIN32)
51 # define CONFIG_NET_BRIDGE
52 #endif
53 
54 static VMChangeStateEntry *net_change_state_entry;
55 static QTAILQ_HEAD(, NetClientState) net_clients;
56 
57 const char *host_net_devices[] = {
58     "tap",
59     "socket",
60     "dump",
61 #ifdef CONFIG_NET_BRIDGE
62     "bridge",
63 #endif
64 #ifdef CONFIG_NETMAP
65     "netmap",
66 #endif
67 #ifdef CONFIG_SLIRP
68     "user",
69 #endif
70 #ifdef CONFIG_VDE
71     "vde",
72 #endif
73     "vhost-user",
74     NULL,
75 };
76 
77 int default_net = 1;
78 
79 /***********************************************************/
80 /* network device redirectors */
81 
82 #if defined(DEBUG_NET)
83 static void hex_dump(FILE *f, const uint8_t *buf, int size)
84 {
85     int len, i, j, c;
86 
87     for(i=0;i<size;i+=16) {
88         len = size - i;
89         if (len > 16)
90             len = 16;
91         fprintf(f, "%08x ", i);
92         for(j=0;j<16;j++) {
93             if (j < len)
94                 fprintf(f, " %02x", buf[i+j]);
95             else
96                 fprintf(f, "   ");
97         }
98         fprintf(f, " ");
99         for(j=0;j<len;j++) {
100             c = buf[i+j];
101             if (c < ' ' || c > '~')
102                 c = '.';
103             fprintf(f, "%c", c);
104         }
105         fprintf(f, "\n");
106     }
107 }
108 #endif
109 
110 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
111 {
112     const char *p, *p1;
113     int len;
114     p = *pp;
115     p1 = strchr(p, sep);
116     if (!p1)
117         return -1;
118     len = p1 - p;
119     p1++;
120     if (buf_size > 0) {
121         if (len > buf_size - 1)
122             len = buf_size - 1;
123         memcpy(buf, p, len);
124         buf[len] = '\0';
125     }
126     *pp = p1;
127     return 0;
128 }
129 
130 int parse_host_port(struct sockaddr_in *saddr, const char *str)
131 {
132     char buf[512];
133     struct hostent *he;
134     const char *p, *r;
135     int port;
136 
137     p = str;
138     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0)
139         return -1;
140     saddr->sin_family = AF_INET;
141     if (buf[0] == '\0') {
142         saddr->sin_addr.s_addr = 0;
143     } else {
144         if (qemu_isdigit(buf[0])) {
145             if (!inet_aton(buf, &saddr->sin_addr))
146                 return -1;
147         } else {
148             if ((he = gethostbyname(buf)) == NULL)
149                 return - 1;
150             saddr->sin_addr = *(struct in_addr *)he->h_addr;
151         }
152     }
153     port = strtol(p, (char **)&r, 0);
154     if (r == p)
155         return -1;
156     saddr->sin_port = htons(port);
157     return 0;
158 }
159 
160 char *qemu_mac_strdup_printf(const uint8_t *macaddr)
161 {
162     return g_strdup_printf("%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
163                            macaddr[0], macaddr[1], macaddr[2],
164                            macaddr[3], macaddr[4], macaddr[5]);
165 }
166 
167 void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6])
168 {
169     snprintf(nc->info_str, sizeof(nc->info_str),
170              "model=%s,macaddr=%02x:%02x:%02x:%02x:%02x:%02x",
171              nc->model,
172              macaddr[0], macaddr[1], macaddr[2],
173              macaddr[3], macaddr[4], macaddr[5]);
174 }
175 
176 static int mac_table[256] = {0};
177 
178 static void qemu_macaddr_set_used(MACAddr *macaddr)
179 {
180     int index;
181 
182     for (index = 0x56; index < 0xFF; index++) {
183         if (macaddr->a[5] == index) {
184             mac_table[index]++;
185         }
186     }
187 }
188 
189 static void qemu_macaddr_set_free(MACAddr *macaddr)
190 {
191     int index;
192     static const MACAddr base = { .a = { 0x52, 0x54, 0x00, 0x12, 0x34, 0 } };
193 
194     if (memcmp(macaddr->a, &base.a, (sizeof(base.a) - 1)) != 0) {
195         return;
196     }
197     for (index = 0x56; index < 0xFF; index++) {
198         if (macaddr->a[5] == index) {
199             mac_table[index]--;
200         }
201     }
202 }
203 
204 static int qemu_macaddr_get_free(void)
205 {
206     int index;
207 
208     for (index = 0x56; index < 0xFF; index++) {
209         if (mac_table[index] == 0) {
210             return index;
211         }
212     }
213 
214     return -1;
215 }
216 
217 void qemu_macaddr_default_if_unset(MACAddr *macaddr)
218 {
219     static const MACAddr zero = { .a = { 0,0,0,0,0,0 } };
220     static const MACAddr base = { .a = { 0x52, 0x54, 0x00, 0x12, 0x34, 0 } };
221 
222     if (memcmp(macaddr, &zero, sizeof(zero)) != 0) {
223         if (memcmp(macaddr->a, &base.a, (sizeof(base.a) - 1)) != 0) {
224             return;
225         } else {
226             qemu_macaddr_set_used(macaddr);
227             return;
228         }
229     }
230 
231     macaddr->a[0] = 0x52;
232     macaddr->a[1] = 0x54;
233     macaddr->a[2] = 0x00;
234     macaddr->a[3] = 0x12;
235     macaddr->a[4] = 0x34;
236     macaddr->a[5] = qemu_macaddr_get_free();
237     qemu_macaddr_set_used(macaddr);
238 }
239 
240 /**
241  * Generate a name for net client
242  *
243  * Only net clients created with the legacy -net option and NICs need this.
244  */
245 static char *assign_name(NetClientState *nc1, const char *model)
246 {
247     NetClientState *nc;
248     int id = 0;
249 
250     QTAILQ_FOREACH(nc, &net_clients, next) {
251         if (nc == nc1) {
252             continue;
253         }
254         if (strcmp(nc->model, model) == 0) {
255             id++;
256         }
257     }
258 
259     return g_strdup_printf("%s.%d", model, id);
260 }
261 
262 static void qemu_net_client_destructor(NetClientState *nc)
263 {
264     g_free(nc);
265 }
266 
267 static void qemu_net_client_setup(NetClientState *nc,
268                                   NetClientInfo *info,
269                                   NetClientState *peer,
270                                   const char *model,
271                                   const char *name,
272                                   NetClientDestructor *destructor)
273 {
274     nc->info = info;
275     nc->model = g_strdup(model);
276     if (name) {
277         nc->name = g_strdup(name);
278     } else {
279         nc->name = assign_name(nc, model);
280     }
281 
282     if (peer) {
283         assert(!peer->peer);
284         nc->peer = peer;
285         peer->peer = nc;
286     }
287     QTAILQ_INSERT_TAIL(&net_clients, nc, next);
288 
289     nc->incoming_queue = qemu_new_net_queue(qemu_deliver_packet_iov, nc);
290     nc->destructor = destructor;
291     QTAILQ_INIT(&nc->filters);
292 }
293 
294 NetClientState *qemu_new_net_client(NetClientInfo *info,
295                                     NetClientState *peer,
296                                     const char *model,
297                                     const char *name)
298 {
299     NetClientState *nc;
300 
301     assert(info->size >= sizeof(NetClientState));
302 
303     nc = g_malloc0(info->size);
304     qemu_net_client_setup(nc, info, peer, model, name,
305                           qemu_net_client_destructor);
306 
307     return nc;
308 }
309 
310 NICState *qemu_new_nic(NetClientInfo *info,
311                        NICConf *conf,
312                        const char *model,
313                        const char *name,
314                        void *opaque)
315 {
316     NetClientState **peers = conf->peers.ncs;
317     NICState *nic;
318     int i, queues = MAX(1, conf->peers.queues);
319 
320     assert(info->type == NET_CLIENT_OPTIONS_KIND_NIC);
321     assert(info->size >= sizeof(NICState));
322 
323     nic = g_malloc0(info->size + sizeof(NetClientState) * queues);
324     nic->ncs = (void *)nic + info->size;
325     nic->conf = conf;
326     nic->opaque = opaque;
327 
328     for (i = 0; i < queues; i++) {
329         qemu_net_client_setup(&nic->ncs[i], info, peers[i], model, name,
330                               NULL);
331         nic->ncs[i].queue_index = i;
332     }
333 
334     return nic;
335 }
336 
337 NetClientState *qemu_get_subqueue(NICState *nic, int queue_index)
338 {
339     return nic->ncs + queue_index;
340 }
341 
342 NetClientState *qemu_get_queue(NICState *nic)
343 {
344     return qemu_get_subqueue(nic, 0);
345 }
346 
347 NICState *qemu_get_nic(NetClientState *nc)
348 {
349     NetClientState *nc0 = nc - nc->queue_index;
350 
351     return (NICState *)((void *)nc0 - nc->info->size);
352 }
353 
354 void *qemu_get_nic_opaque(NetClientState *nc)
355 {
356     NICState *nic = qemu_get_nic(nc);
357 
358     return nic->opaque;
359 }
360 
361 static void qemu_cleanup_net_client(NetClientState *nc)
362 {
363     QTAILQ_REMOVE(&net_clients, nc, next);
364 
365     if (nc->info->cleanup) {
366         nc->info->cleanup(nc);
367     }
368 }
369 
370 static void qemu_free_net_client(NetClientState *nc)
371 {
372     if (nc->incoming_queue) {
373         qemu_del_net_queue(nc->incoming_queue);
374     }
375     if (nc->peer) {
376         nc->peer->peer = NULL;
377     }
378     g_free(nc->name);
379     g_free(nc->model);
380     if (nc->destructor) {
381         nc->destructor(nc);
382     }
383 }
384 
385 void qemu_del_net_client(NetClientState *nc)
386 {
387     NetClientState *ncs[MAX_QUEUE_NUM];
388     int queues, i;
389     NetFilterState *nf, *next;
390 
391     assert(nc->info->type != NET_CLIENT_OPTIONS_KIND_NIC);
392 
393     /* If the NetClientState belongs to a multiqueue backend, we will change all
394      * other NetClientStates also.
395      */
396     queues = qemu_find_net_clients_except(nc->name, ncs,
397                                           NET_CLIENT_OPTIONS_KIND_NIC,
398                                           MAX_QUEUE_NUM);
399     assert(queues != 0);
400 
401     QTAILQ_FOREACH_SAFE(nf, &nc->filters, next, next) {
402         object_unparent(OBJECT(nf));
403     }
404 
405     /* If there is a peer NIC, delete and cleanup client, but do not free. */
406     if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
407         NICState *nic = qemu_get_nic(nc->peer);
408         if (nic->peer_deleted) {
409             return;
410         }
411         nic->peer_deleted = true;
412 
413         for (i = 0; i < queues; i++) {
414             ncs[i]->peer->link_down = true;
415         }
416 
417         if (nc->peer->info->link_status_changed) {
418             nc->peer->info->link_status_changed(nc->peer);
419         }
420 
421         for (i = 0; i < queues; i++) {
422             qemu_cleanup_net_client(ncs[i]);
423         }
424 
425         return;
426     }
427 
428     for (i = 0; i < queues; i++) {
429         qemu_cleanup_net_client(ncs[i]);
430         qemu_free_net_client(ncs[i]);
431     }
432 }
433 
434 void qemu_del_nic(NICState *nic)
435 {
436     int i, queues = MAX(nic->conf->peers.queues, 1);
437 
438     qemu_macaddr_set_free(&nic->conf->macaddr);
439 
440     /* If this is a peer NIC and peer has already been deleted, free it now. */
441     if (nic->peer_deleted) {
442         for (i = 0; i < queues; i++) {
443             qemu_free_net_client(qemu_get_subqueue(nic, i)->peer);
444         }
445     }
446 
447     for (i = queues - 1; i >= 0; i--) {
448         NetClientState *nc = qemu_get_subqueue(nic, i);
449 
450         qemu_cleanup_net_client(nc);
451         qemu_free_net_client(nc);
452     }
453 
454     g_free(nic);
455 }
456 
457 void qemu_foreach_nic(qemu_nic_foreach func, void *opaque)
458 {
459     NetClientState *nc;
460 
461     QTAILQ_FOREACH(nc, &net_clients, next) {
462         if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
463             if (nc->queue_index == 0) {
464                 func(qemu_get_nic(nc), opaque);
465             }
466         }
467     }
468 }
469 
470 bool qemu_has_ufo(NetClientState *nc)
471 {
472     if (!nc || !nc->info->has_ufo) {
473         return false;
474     }
475 
476     return nc->info->has_ufo(nc);
477 }
478 
479 bool qemu_has_vnet_hdr(NetClientState *nc)
480 {
481     if (!nc || !nc->info->has_vnet_hdr) {
482         return false;
483     }
484 
485     return nc->info->has_vnet_hdr(nc);
486 }
487 
488 bool qemu_has_vnet_hdr_len(NetClientState *nc, int len)
489 {
490     if (!nc || !nc->info->has_vnet_hdr_len) {
491         return false;
492     }
493 
494     return nc->info->has_vnet_hdr_len(nc, len);
495 }
496 
497 void qemu_using_vnet_hdr(NetClientState *nc, bool enable)
498 {
499     if (!nc || !nc->info->using_vnet_hdr) {
500         return;
501     }
502 
503     nc->info->using_vnet_hdr(nc, enable);
504 }
505 
506 void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
507                           int ecn, int ufo)
508 {
509     if (!nc || !nc->info->set_offload) {
510         return;
511     }
512 
513     nc->info->set_offload(nc, csum, tso4, tso6, ecn, ufo);
514 }
515 
516 void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
517 {
518     if (!nc || !nc->info->set_vnet_hdr_len) {
519         return;
520     }
521 
522     nc->info->set_vnet_hdr_len(nc, len);
523 }
524 
525 int qemu_set_vnet_le(NetClientState *nc, bool is_le)
526 {
527 #ifdef HOST_WORDS_BIGENDIAN
528     if (!nc || !nc->info->set_vnet_le) {
529         return -ENOSYS;
530     }
531 
532     return nc->info->set_vnet_le(nc, is_le);
533 #else
534     return 0;
535 #endif
536 }
537 
538 int qemu_set_vnet_be(NetClientState *nc, bool is_be)
539 {
540 #ifdef HOST_WORDS_BIGENDIAN
541     return 0;
542 #else
543     if (!nc || !nc->info->set_vnet_be) {
544         return -ENOSYS;
545     }
546 
547     return nc->info->set_vnet_be(nc, is_be);
548 #endif
549 }
550 
551 int qemu_can_send_packet(NetClientState *sender)
552 {
553     int vm_running = runstate_is_running();
554 
555     if (!vm_running) {
556         return 0;
557     }
558 
559     if (!sender->peer) {
560         return 1;
561     }
562 
563     if (sender->peer->receive_disabled) {
564         return 0;
565     } else if (sender->peer->info->can_receive &&
566                !sender->peer->info->can_receive(sender->peer)) {
567         return 0;
568     }
569     return 1;
570 }
571 
572 static ssize_t filter_receive_iov(NetClientState *nc,
573                                   NetFilterDirection direction,
574                                   NetClientState *sender,
575                                   unsigned flags,
576                                   const struct iovec *iov,
577                                   int iovcnt,
578                                   NetPacketSent *sent_cb)
579 {
580     ssize_t ret = 0;
581     NetFilterState *nf = NULL;
582 
583     QTAILQ_FOREACH(nf, &nc->filters, next) {
584         ret = qemu_netfilter_receive(nf, direction, sender, flags, iov,
585                                      iovcnt, sent_cb);
586         if (ret) {
587             return ret;
588         }
589     }
590 
591     return ret;
592 }
593 
594 static ssize_t filter_receive(NetClientState *nc,
595                               NetFilterDirection direction,
596                               NetClientState *sender,
597                               unsigned flags,
598                               const uint8_t *data,
599                               size_t size,
600                               NetPacketSent *sent_cb)
601 {
602     struct iovec iov = {
603         .iov_base = (void *)data,
604         .iov_len = size
605     };
606 
607     return filter_receive_iov(nc, direction, sender, flags, &iov, 1, sent_cb);
608 }
609 
610 void qemu_purge_queued_packets(NetClientState *nc)
611 {
612     if (!nc->peer) {
613         return;
614     }
615 
616     qemu_net_queue_purge(nc->peer->incoming_queue, nc);
617 }
618 
619 static
620 void qemu_flush_or_purge_queued_packets(NetClientState *nc, bool purge)
621 {
622     nc->receive_disabled = 0;
623 
624     if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_HUBPORT) {
625         if (net_hub_flush(nc->peer)) {
626             qemu_notify_event();
627         }
628     }
629     if (qemu_net_queue_flush(nc->incoming_queue)) {
630         /* We emptied the queue successfully, signal to the IO thread to repoll
631          * the file descriptor (for tap, for example).
632          */
633         qemu_notify_event();
634     } else if (purge) {
635         /* Unable to empty the queue, purge remaining packets */
636         qemu_net_queue_purge(nc->incoming_queue, nc);
637     }
638 }
639 
640 void qemu_flush_queued_packets(NetClientState *nc)
641 {
642     qemu_flush_or_purge_queued_packets(nc, false);
643 }
644 
645 static ssize_t qemu_send_packet_async_with_flags(NetClientState *sender,
646                                                  unsigned flags,
647                                                  const uint8_t *buf, int size,
648                                                  NetPacketSent *sent_cb)
649 {
650     NetQueue *queue;
651     int ret;
652 
653 #ifdef DEBUG_NET
654     printf("qemu_send_packet_async:\n");
655     hex_dump(stdout, buf, size);
656 #endif
657 
658     if (sender->link_down || !sender->peer) {
659         return size;
660     }
661 
662     /* Let filters handle the packet first */
663     ret = filter_receive(sender, NET_FILTER_DIRECTION_TX,
664                          sender, flags, buf, size, sent_cb);
665     if (ret) {
666         return ret;
667     }
668 
669     ret = filter_receive(sender->peer, NET_FILTER_DIRECTION_RX,
670                          sender, flags, buf, size, sent_cb);
671     if (ret) {
672         return ret;
673     }
674 
675     queue = sender->peer->incoming_queue;
676 
677     return qemu_net_queue_send(queue, sender, flags, buf, size, sent_cb);
678 }
679 
680 ssize_t qemu_send_packet_async(NetClientState *sender,
681                                const uint8_t *buf, int size,
682                                NetPacketSent *sent_cb)
683 {
684     return qemu_send_packet_async_with_flags(sender, QEMU_NET_PACKET_FLAG_NONE,
685                                              buf, size, sent_cb);
686 }
687 
688 void qemu_send_packet(NetClientState *nc, const uint8_t *buf, int size)
689 {
690     qemu_send_packet_async(nc, buf, size, NULL);
691 }
692 
693 ssize_t qemu_send_packet_raw(NetClientState *nc, const uint8_t *buf, int size)
694 {
695     return qemu_send_packet_async_with_flags(nc, QEMU_NET_PACKET_FLAG_RAW,
696                                              buf, size, NULL);
697 }
698 
699 static ssize_t nc_sendv_compat(NetClientState *nc, const struct iovec *iov,
700                                int iovcnt, unsigned flags)
701 {
702     uint8_t buf[NET_BUFSIZE];
703     uint8_t *buffer;
704     size_t offset;
705 
706     if (iovcnt == 1) {
707         buffer = iov[0].iov_base;
708         offset = iov[0].iov_len;
709     } else {
710         buffer = buf;
711         offset = iov_to_buf(iov, iovcnt, 0, buffer, sizeof(buffer));
712     }
713 
714     if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
715         return nc->info->receive_raw(nc, buffer, offset);
716     } else {
717         return nc->info->receive(nc, buffer, offset);
718     }
719 }
720 
721 ssize_t qemu_deliver_packet_iov(NetClientState *sender,
722                                 unsigned flags,
723                                 const struct iovec *iov,
724                                 int iovcnt,
725                                 void *opaque)
726 {
727     NetClientState *nc = opaque;
728     int ret;
729 
730     if (nc->link_down) {
731         return iov_size(iov, iovcnt);
732     }
733 
734     if (nc->receive_disabled) {
735         return 0;
736     }
737 
738     if (nc->info->receive_iov) {
739         ret = nc->info->receive_iov(nc, iov, iovcnt);
740     } else {
741         ret = nc_sendv_compat(nc, iov, iovcnt, flags);
742     }
743 
744     if (ret == 0) {
745         nc->receive_disabled = 1;
746     }
747 
748     return ret;
749 }
750 
751 ssize_t qemu_sendv_packet_async(NetClientState *sender,
752                                 const struct iovec *iov, int iovcnt,
753                                 NetPacketSent *sent_cb)
754 {
755     NetQueue *queue;
756     int ret;
757 
758     if (sender->link_down || !sender->peer) {
759         return iov_size(iov, iovcnt);
760     }
761 
762     /* Let filters handle the packet first */
763     ret = filter_receive_iov(sender, NET_FILTER_DIRECTION_TX, sender,
764                              QEMU_NET_PACKET_FLAG_NONE, iov, iovcnt, sent_cb);
765     if (ret) {
766         return ret;
767     }
768 
769     ret = filter_receive_iov(sender->peer, NET_FILTER_DIRECTION_RX, sender,
770                              QEMU_NET_PACKET_FLAG_NONE, iov, iovcnt, sent_cb);
771     if (ret) {
772         return ret;
773     }
774 
775     queue = sender->peer->incoming_queue;
776 
777     return qemu_net_queue_send_iov(queue, sender,
778                                    QEMU_NET_PACKET_FLAG_NONE,
779                                    iov, iovcnt, sent_cb);
780 }
781 
782 ssize_t
783 qemu_sendv_packet(NetClientState *nc, const struct iovec *iov, int iovcnt)
784 {
785     return qemu_sendv_packet_async(nc, iov, iovcnt, NULL);
786 }
787 
788 NetClientState *qemu_find_netdev(const char *id)
789 {
790     NetClientState *nc;
791 
792     QTAILQ_FOREACH(nc, &net_clients, next) {
793         if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC)
794             continue;
795         if (!strcmp(nc->name, id)) {
796             return nc;
797         }
798     }
799 
800     return NULL;
801 }
802 
803 int qemu_find_net_clients_except(const char *id, NetClientState **ncs,
804                                  NetClientOptionsKind type, int max)
805 {
806     NetClientState *nc;
807     int ret = 0;
808 
809     QTAILQ_FOREACH(nc, &net_clients, next) {
810         if (nc->info->type == type) {
811             continue;
812         }
813         if (!id || !strcmp(nc->name, id)) {
814             if (ret < max) {
815                 ncs[ret] = nc;
816             }
817             ret++;
818         }
819     }
820 
821     return ret;
822 }
823 
824 static int nic_get_free_idx(void)
825 {
826     int index;
827 
828     for (index = 0; index < MAX_NICS; index++)
829         if (!nd_table[index].used)
830             return index;
831     return -1;
832 }
833 
834 int qemu_show_nic_models(const char *arg, const char *const *models)
835 {
836     int i;
837 
838     if (!arg || !is_help_option(arg)) {
839         return 0;
840     }
841 
842     fprintf(stderr, "qemu: Supported NIC models: ");
843     for (i = 0 ; models[i]; i++)
844         fprintf(stderr, "%s%c", models[i], models[i+1] ? ',' : '\n');
845     return 1;
846 }
847 
848 void qemu_check_nic_model(NICInfo *nd, const char *model)
849 {
850     const char *models[2];
851 
852     models[0] = model;
853     models[1] = NULL;
854 
855     if (qemu_show_nic_models(nd->model, models))
856         exit(0);
857     if (qemu_find_nic_model(nd, models, model) < 0)
858         exit(1);
859 }
860 
861 int qemu_find_nic_model(NICInfo *nd, const char * const *models,
862                         const char *default_model)
863 {
864     int i;
865 
866     if (!nd->model)
867         nd->model = g_strdup(default_model);
868 
869     for (i = 0 ; models[i]; i++) {
870         if (strcmp(nd->model, models[i]) == 0)
871             return i;
872     }
873 
874     error_report("Unsupported NIC model: %s", nd->model);
875     return -1;
876 }
877 
878 static int net_init_nic(const NetClientOptions *opts, const char *name,
879                         NetClientState *peer, Error **errp)
880 {
881     int idx;
882     NICInfo *nd;
883     const NetLegacyNicOptions *nic;
884 
885     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_NIC);
886     nic = opts->nic;
887 
888     idx = nic_get_free_idx();
889     if (idx == -1 || nb_nics >= MAX_NICS) {
890         error_setg(errp, "too many NICs");
891         return -1;
892     }
893 
894     nd = &nd_table[idx];
895 
896     memset(nd, 0, sizeof(*nd));
897 
898     if (nic->has_netdev) {
899         nd->netdev = qemu_find_netdev(nic->netdev);
900         if (!nd->netdev) {
901             error_setg(errp, "netdev '%s' not found", nic->netdev);
902             return -1;
903         }
904     } else {
905         assert(peer);
906         nd->netdev = peer;
907     }
908     nd->name = g_strdup(name);
909     if (nic->has_model) {
910         nd->model = g_strdup(nic->model);
911     }
912     if (nic->has_addr) {
913         nd->devaddr = g_strdup(nic->addr);
914     }
915 
916     if (nic->has_macaddr &&
917         net_parse_macaddr(nd->macaddr.a, nic->macaddr) < 0) {
918         error_setg(errp, "invalid syntax for ethernet address");
919         return -1;
920     }
921     if (nic->has_macaddr &&
922         is_multicast_ether_addr(nd->macaddr.a)) {
923         error_setg(errp,
924                    "NIC cannot have multicast MAC address (odd 1st byte)");
925         return -1;
926     }
927     qemu_macaddr_default_if_unset(&nd->macaddr);
928 
929     if (nic->has_vectors) {
930         if (nic->vectors > 0x7ffffff) {
931             error_setg(errp, "invalid # of vectors: %"PRIu32, nic->vectors);
932             return -1;
933         }
934         nd->nvectors = nic->vectors;
935     } else {
936         nd->nvectors = DEV_NVECTORS_UNSPECIFIED;
937     }
938 
939     nd->used = 1;
940     nb_nics++;
941 
942     return idx;
943 }
944 
945 
946 static int (* const net_client_init_fun[NET_CLIENT_OPTIONS_KIND_MAX])(
947     const NetClientOptions *opts,
948     const char *name,
949     NetClientState *peer, Error **errp) = {
950         [NET_CLIENT_OPTIONS_KIND_NIC]       = net_init_nic,
951 #ifdef CONFIG_SLIRP
952         [NET_CLIENT_OPTIONS_KIND_USER]      = net_init_slirp,
953 #endif
954         [NET_CLIENT_OPTIONS_KIND_TAP]       = net_init_tap,
955         [NET_CLIENT_OPTIONS_KIND_SOCKET]    = net_init_socket,
956 #ifdef CONFIG_VDE
957         [NET_CLIENT_OPTIONS_KIND_VDE]       = net_init_vde,
958 #endif
959 #ifdef CONFIG_NETMAP
960         [NET_CLIENT_OPTIONS_KIND_NETMAP]    = net_init_netmap,
961 #endif
962         [NET_CLIENT_OPTIONS_KIND_DUMP]      = net_init_dump,
963 #ifdef CONFIG_NET_BRIDGE
964         [NET_CLIENT_OPTIONS_KIND_BRIDGE]    = net_init_bridge,
965 #endif
966         [NET_CLIENT_OPTIONS_KIND_HUBPORT]   = net_init_hubport,
967 #ifdef CONFIG_VHOST_NET_USED
968         [NET_CLIENT_OPTIONS_KIND_VHOST_USER] = net_init_vhost_user,
969 #endif
970 #ifdef CONFIG_L2TPV3
971         [NET_CLIENT_OPTIONS_KIND_L2TPV3]    = net_init_l2tpv3,
972 #endif
973 };
974 
975 
976 static int net_client_init1(const void *object, int is_netdev, Error **errp)
977 {
978     const NetClientOptions *opts;
979     const char *name;
980     NetClientState *peer = NULL;
981 
982     if (is_netdev) {
983         const Netdev *netdev = object;
984         opts = netdev->opts;
985         name = netdev->id;
986 
987         if (opts->kind == NET_CLIENT_OPTIONS_KIND_DUMP ||
988             opts->kind == NET_CLIENT_OPTIONS_KIND_NIC ||
989             !net_client_init_fun[opts->kind]) {
990             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type",
991                        "a netdev backend type");
992             return -1;
993         }
994     } else {
995         const NetLegacy *net = object;
996         opts = net->opts;
997         /* missing optional values have been initialized to "all bits zero" */
998         name = net->has_id ? net->id : net->name;
999 
1000         if (opts->kind == NET_CLIENT_OPTIONS_KIND_NONE) {
1001             return 0; /* nothing to do */
1002         }
1003         if (opts->kind == NET_CLIENT_OPTIONS_KIND_HUBPORT) {
1004             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type",
1005                        "a net type");
1006             return -1;
1007         }
1008 
1009         if (!net_client_init_fun[opts->kind]) {
1010             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type",
1011                        "a net backend type (maybe it is not compiled "
1012                        "into this binary)");
1013             return -1;
1014         }
1015 
1016         /* Do not add to a vlan if it's a nic with a netdev= parameter. */
1017         if (opts->kind != NET_CLIENT_OPTIONS_KIND_NIC ||
1018             !opts->nic->has_netdev) {
1019             peer = net_hub_add_port(net->has_vlan ? net->vlan : 0, NULL);
1020         }
1021     }
1022 
1023     if (net_client_init_fun[opts->kind](opts, name, peer, errp) < 0) {
1024         /* FIXME drop when all init functions store an Error */
1025         if (errp && !*errp) {
1026             error_setg(errp, QERR_DEVICE_INIT_FAILED,
1027                        NetClientOptionsKind_lookup[opts->kind]);
1028         }
1029         return -1;
1030     }
1031     return 0;
1032 }
1033 
1034 
1035 static void net_visit(Visitor *v, int is_netdev, void **object, Error **errp)
1036 {
1037     if (is_netdev) {
1038         visit_type_Netdev(v, (Netdev **)object, NULL, errp);
1039     } else {
1040         visit_type_NetLegacy(v, (NetLegacy **)object, NULL, errp);
1041     }
1042 }
1043 
1044 
1045 int net_client_init(QemuOpts *opts, int is_netdev, Error **errp)
1046 {
1047     void *object = NULL;
1048     Error *err = NULL;
1049     int ret = -1;
1050 
1051     {
1052         OptsVisitor *ov = opts_visitor_new(opts);
1053 
1054         net_visit(opts_get_visitor(ov), is_netdev, &object, &err);
1055         opts_visitor_cleanup(ov);
1056     }
1057 
1058     if (!err) {
1059         ret = net_client_init1(object, is_netdev, &err);
1060     }
1061 
1062     if (object) {
1063         QapiDeallocVisitor *dv = qapi_dealloc_visitor_new();
1064 
1065         net_visit(qapi_dealloc_get_visitor(dv), is_netdev, &object, NULL);
1066         qapi_dealloc_visitor_cleanup(dv);
1067     }
1068 
1069     error_propagate(errp, err);
1070     return ret;
1071 }
1072 
1073 
1074 static int net_host_check_device(const char *device)
1075 {
1076     int i;
1077     for (i = 0; host_net_devices[i]; i++) {
1078         if (!strncmp(host_net_devices[i], device,
1079                      strlen(host_net_devices[i]))) {
1080             return 1;
1081         }
1082     }
1083 
1084     return 0;
1085 }
1086 
1087 void hmp_host_net_add(Monitor *mon, const QDict *qdict)
1088 {
1089     const char *device = qdict_get_str(qdict, "device");
1090     const char *opts_str = qdict_get_try_str(qdict, "opts");
1091     Error *local_err = NULL;
1092     QemuOpts *opts;
1093 
1094     if (!net_host_check_device(device)) {
1095         monitor_printf(mon, "invalid host network device %s\n", device);
1096         return;
1097     }
1098 
1099     opts = qemu_opts_parse_noisily(qemu_find_opts("net"),
1100                                    opts_str ? opts_str : "", false);
1101     if (!opts) {
1102         return;
1103     }
1104 
1105     qemu_opt_set(opts, "type", device, &error_abort);
1106 
1107     net_client_init(opts, 0, &local_err);
1108     if (local_err) {
1109         error_report_err(local_err);
1110         monitor_printf(mon, "adding host network device %s failed\n", device);
1111     }
1112 }
1113 
1114 void hmp_host_net_remove(Monitor *mon, const QDict *qdict)
1115 {
1116     NetClientState *nc;
1117     int vlan_id = qdict_get_int(qdict, "vlan_id");
1118     const char *device = qdict_get_str(qdict, "device");
1119 
1120     nc = net_hub_find_client_by_name(vlan_id, device);
1121     if (!nc) {
1122         error_report("Host network device '%s' on hub '%d' not found",
1123                      device, vlan_id);
1124         return;
1125     }
1126     if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
1127         error_report("invalid host network device '%s'", device);
1128         return;
1129     }
1130 
1131     qemu_del_net_client(nc->peer);
1132     qemu_del_net_client(nc);
1133 }
1134 
1135 void netdev_add(QemuOpts *opts, Error **errp)
1136 {
1137     net_client_init(opts, 1, errp);
1138 }
1139 
1140 void qmp_netdev_add(QDict *qdict, QObject **ret, Error **errp)
1141 {
1142     Error *local_err = NULL;
1143     QemuOptsList *opts_list;
1144     QemuOpts *opts;
1145 
1146     opts_list = qemu_find_opts_err("netdev", &local_err);
1147     if (local_err) {
1148         goto out;
1149     }
1150 
1151     opts = qemu_opts_from_qdict(opts_list, qdict, &local_err);
1152     if (local_err) {
1153         goto out;
1154     }
1155 
1156     netdev_add(opts, &local_err);
1157     if (local_err) {
1158         qemu_opts_del(opts);
1159         goto out;
1160     }
1161 
1162 out:
1163     error_propagate(errp, local_err);
1164 }
1165 
1166 void qmp_netdev_del(const char *id, Error **errp)
1167 {
1168     NetClientState *nc;
1169     QemuOpts *opts;
1170 
1171     nc = qemu_find_netdev(id);
1172     if (!nc) {
1173         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
1174                   "Device '%s' not found", id);
1175         return;
1176     }
1177 
1178     opts = qemu_opts_find(qemu_find_opts_err("netdev", NULL), id);
1179     if (!opts) {
1180         error_setg(errp, "Device '%s' is not a netdev", id);
1181         return;
1182     }
1183 
1184     qemu_del_net_client(nc);
1185     qemu_opts_del(opts);
1186 }
1187 
1188 void print_net_client(Monitor *mon, NetClientState *nc)
1189 {
1190     NetFilterState *nf;
1191 
1192     monitor_printf(mon, "%s: index=%d,type=%s,%s\n", nc->name,
1193                    nc->queue_index,
1194                    NetClientOptionsKind_lookup[nc->info->type],
1195                    nc->info_str);
1196     if (!QTAILQ_EMPTY(&nc->filters)) {
1197         monitor_printf(mon, "filters:\n");
1198     }
1199     QTAILQ_FOREACH(nf, &nc->filters, next) {
1200         monitor_printf(mon, "  - %s: type=%s%s\n",
1201                        object_get_canonical_path_component(OBJECT(nf)),
1202                        object_get_typename(OBJECT(nf)),
1203                        nf->info_str);
1204     }
1205 }
1206 
1207 RxFilterInfoList *qmp_query_rx_filter(bool has_name, const char *name,
1208                                       Error **errp)
1209 {
1210     NetClientState *nc;
1211     RxFilterInfoList *filter_list = NULL, *last_entry = NULL;
1212 
1213     QTAILQ_FOREACH(nc, &net_clients, next) {
1214         RxFilterInfoList *entry;
1215         RxFilterInfo *info;
1216 
1217         if (has_name && strcmp(nc->name, name) != 0) {
1218             continue;
1219         }
1220 
1221         /* only query rx-filter information of NIC */
1222         if (nc->info->type != NET_CLIENT_OPTIONS_KIND_NIC) {
1223             if (has_name) {
1224                 error_setg(errp, "net client(%s) isn't a NIC", name);
1225                 return NULL;
1226             }
1227             continue;
1228         }
1229 
1230         if (nc->info->query_rx_filter) {
1231             info = nc->info->query_rx_filter(nc);
1232             entry = g_malloc0(sizeof(*entry));
1233             entry->value = info;
1234 
1235             if (!filter_list) {
1236                 filter_list = entry;
1237             } else {
1238                 last_entry->next = entry;
1239             }
1240             last_entry = entry;
1241         } else if (has_name) {
1242             error_setg(errp, "net client(%s) doesn't support"
1243                        " rx-filter querying", name);
1244             return NULL;
1245         }
1246 
1247         if (has_name) {
1248             break;
1249         }
1250     }
1251 
1252     if (filter_list == NULL && has_name) {
1253         error_setg(errp, "invalid net client name: %s", name);
1254     }
1255 
1256     return filter_list;
1257 }
1258 
1259 void hmp_info_network(Monitor *mon, const QDict *qdict)
1260 {
1261     NetClientState *nc, *peer;
1262     NetClientOptionsKind type;
1263 
1264     net_hub_info(mon);
1265 
1266     QTAILQ_FOREACH(nc, &net_clients, next) {
1267         peer = nc->peer;
1268         type = nc->info->type;
1269 
1270         /* Skip if already printed in hub info */
1271         if (net_hub_id_for_client(nc, NULL) == 0) {
1272             continue;
1273         }
1274 
1275         if (!peer || type == NET_CLIENT_OPTIONS_KIND_NIC) {
1276             print_net_client(mon, nc);
1277         } /* else it's a netdev connected to a NIC, printed with the NIC */
1278         if (peer && type == NET_CLIENT_OPTIONS_KIND_NIC) {
1279             monitor_printf(mon, " \\ ");
1280             print_net_client(mon, peer);
1281         }
1282     }
1283 }
1284 
1285 void qmp_set_link(const char *name, bool up, Error **errp)
1286 {
1287     NetClientState *ncs[MAX_QUEUE_NUM];
1288     NetClientState *nc;
1289     int queues, i;
1290 
1291     queues = qemu_find_net_clients_except(name, ncs,
1292                                           NET_CLIENT_OPTIONS_KIND_MAX,
1293                                           MAX_QUEUE_NUM);
1294 
1295     if (queues == 0) {
1296         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
1297                   "Device '%s' not found", name);
1298         return;
1299     }
1300     nc = ncs[0];
1301 
1302     for (i = 0; i < queues; i++) {
1303         ncs[i]->link_down = !up;
1304     }
1305 
1306     if (nc->info->link_status_changed) {
1307         nc->info->link_status_changed(nc);
1308     }
1309 
1310     if (nc->peer) {
1311         /* Change peer link only if the peer is NIC and then notify peer.
1312          * If the peer is a HUBPORT or a backend, we do not change the
1313          * link status.
1314          *
1315          * This behavior is compatible with qemu vlans where there could be
1316          * multiple clients that can still communicate with each other in
1317          * disconnected mode. For now maintain this compatibility.
1318          */
1319         if (nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
1320             for (i = 0; i < queues; i++) {
1321                 ncs[i]->peer->link_down = !up;
1322             }
1323         }
1324         if (nc->peer->info->link_status_changed) {
1325             nc->peer->info->link_status_changed(nc->peer);
1326         }
1327     }
1328 }
1329 
1330 static void net_vm_change_state_handler(void *opaque, int running,
1331                                         RunState state)
1332 {
1333     NetClientState *nc;
1334     NetClientState *tmp;
1335 
1336     QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) {
1337         if (running) {
1338             /* Flush queued packets and wake up backends. */
1339             if (nc->peer && qemu_can_send_packet(nc)) {
1340                 qemu_flush_queued_packets(nc->peer);
1341             }
1342         } else {
1343             /* Complete all queued packets, to guarantee we don't modify
1344              * state later when VM is not running.
1345              */
1346             qemu_flush_or_purge_queued_packets(nc, true);
1347         }
1348     }
1349 }
1350 
1351 void net_cleanup(void)
1352 {
1353     NetClientState *nc;
1354 
1355     /* We may del multiple entries during qemu_del_net_client(),
1356      * so QTAILQ_FOREACH_SAFE() is also not safe here.
1357      */
1358     while (!QTAILQ_EMPTY(&net_clients)) {
1359         nc = QTAILQ_FIRST(&net_clients);
1360         if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
1361             qemu_del_nic(qemu_get_nic(nc));
1362         } else {
1363             qemu_del_net_client(nc);
1364         }
1365     }
1366 
1367     qemu_del_vm_change_state_handler(net_change_state_entry);
1368 }
1369 
1370 void net_check_clients(void)
1371 {
1372     NetClientState *nc;
1373     int i;
1374 
1375     /* Don't warn about the default network setup that you get if
1376      * no command line -net or -netdev options are specified. There
1377      * are two cases that we would otherwise complain about:
1378      * (1) board doesn't support a NIC but the implicit "-net nic"
1379      * requested one
1380      * (2) CONFIG_SLIRP not set, in which case the implicit "-net nic"
1381      * sets up a nic that isn't connected to anything.
1382      */
1383     if (default_net) {
1384         return;
1385     }
1386 
1387     net_hub_check_clients();
1388 
1389     QTAILQ_FOREACH(nc, &net_clients, next) {
1390         if (!nc->peer) {
1391             fprintf(stderr, "Warning: %s %s has no peer\n",
1392                     nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC ?
1393                     "nic" : "netdev", nc->name);
1394         }
1395     }
1396 
1397     /* Check that all NICs requested via -net nic actually got created.
1398      * NICs created via -device don't need to be checked here because
1399      * they are always instantiated.
1400      */
1401     for (i = 0; i < MAX_NICS; i++) {
1402         NICInfo *nd = &nd_table[i];
1403         if (nd->used && !nd->instantiated) {
1404             fprintf(stderr, "Warning: requested NIC (%s, model %s) "
1405                     "was not created (not supported by this machine?)\n",
1406                     nd->name ? nd->name : "anonymous",
1407                     nd->model ? nd->model : "unspecified");
1408         }
1409     }
1410 }
1411 
1412 static int net_init_client(void *dummy, QemuOpts *opts, Error **errp)
1413 {
1414     Error *local_err = NULL;
1415 
1416     net_client_init(opts, 0, &local_err);
1417     if (local_err) {
1418         error_report_err(local_err);
1419         return -1;
1420     }
1421 
1422     return 0;
1423 }
1424 
1425 static int net_init_netdev(void *dummy, QemuOpts *opts, Error **errp)
1426 {
1427     Error *local_err = NULL;
1428     int ret;
1429 
1430     ret = net_client_init(opts, 1, &local_err);
1431     if (local_err) {
1432         error_report_err(local_err);
1433         return -1;
1434     }
1435 
1436     return ret;
1437 }
1438 
1439 int net_init_clients(void)
1440 {
1441     QemuOptsList *net = qemu_find_opts("net");
1442 
1443     if (default_net) {
1444         /* if no clients, we use a default config */
1445         qemu_opts_set(net, NULL, "type", "nic", &error_abort);
1446 #ifdef CONFIG_SLIRP
1447         qemu_opts_set(net, NULL, "type", "user", &error_abort);
1448 #endif
1449     }
1450 
1451     net_change_state_entry =
1452         qemu_add_vm_change_state_handler(net_vm_change_state_handler, NULL);
1453 
1454     QTAILQ_INIT(&net_clients);
1455 
1456     if (qemu_opts_foreach(qemu_find_opts("netdev"),
1457                           net_init_netdev, NULL, NULL)) {
1458         return -1;
1459     }
1460 
1461     if (qemu_opts_foreach(net, net_init_client, NULL, NULL)) {
1462         return -1;
1463     }
1464 
1465     return 0;
1466 }
1467 
1468 int net_client_parse(QemuOptsList *opts_list, const char *optarg)
1469 {
1470 #if defined(CONFIG_SLIRP)
1471     int ret;
1472     if (net_slirp_parse_legacy(opts_list, optarg, &ret)) {
1473         return ret;
1474     }
1475 #endif
1476 
1477     if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
1478         return -1;
1479     }
1480 
1481     default_net = 0;
1482     return 0;
1483 }
1484 
1485 /* From FreeBSD */
1486 /* XXX: optimize */
1487 unsigned compute_mcast_idx(const uint8_t *ep)
1488 {
1489     uint32_t crc;
1490     int carry, i, j;
1491     uint8_t b;
1492 
1493     crc = 0xffffffff;
1494     for (i = 0; i < 6; i++) {
1495         b = *ep++;
1496         for (j = 0; j < 8; j++) {
1497             carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
1498             crc <<= 1;
1499             b >>= 1;
1500             if (carry) {
1501                 crc = ((crc ^ POLYNOMIAL) | carry);
1502             }
1503         }
1504     }
1505     return crc >> 26;
1506 }
1507 
1508 QemuOptsList qemu_netdev_opts = {
1509     .name = "netdev",
1510     .implied_opt_name = "type",
1511     .head = QTAILQ_HEAD_INITIALIZER(qemu_netdev_opts.head),
1512     .desc = {
1513         /*
1514          * no elements => accept any params
1515          * validation will happen later
1516          */
1517         { /* end of list */ }
1518     },
1519 };
1520 
1521 QemuOptsList qemu_net_opts = {
1522     .name = "net",
1523     .implied_opt_name = "type",
1524     .head = QTAILQ_HEAD_INITIALIZER(qemu_net_opts.head),
1525     .desc = {
1526         /*
1527          * no elements => accept any params
1528          * validation will happen later
1529          */
1530         { /* end of list */ }
1531     },
1532 };
1533