xref: /openbmc/qemu/net/slirp.c (revision f348b6d1a53e5271cf1c9f9acc4646b4b98c1771)
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 "qemu/osdep.h"
25 #include "net/slirp.h"
26 
27 
28 #ifndef _WIN32
29 #include <pwd.h>
30 #include <sys/wait.h>
31 #endif
32 #include "net/net.h"
33 #include "clients.h"
34 #include "hub.h"
35 #include "monitor/monitor.h"
36 #include "qemu/error-report.h"
37 #include "qemu/sockets.h"
38 #include "slirp/libslirp.h"
39 #include "slirp/ip6.h"
40 #include "sysemu/char.h"
41 #include "qemu/cutils.h"
42 
43 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
44 {
45     const char *p, *p1;
46     int len;
47     p = *pp;
48     p1 = strchr(p, sep);
49     if (!p1)
50         return -1;
51     len = p1 - p;
52     p1++;
53     if (buf_size > 0) {
54         if (len > buf_size - 1)
55             len = buf_size - 1;
56         memcpy(buf, p, len);
57         buf[len] = '\0';
58     }
59     *pp = p1;
60     return 0;
61 }
62 
63 /* slirp network adapter */
64 
65 #define SLIRP_CFG_HOSTFWD 1
66 #define SLIRP_CFG_LEGACY  2
67 
68 struct slirp_config_str {
69     struct slirp_config_str *next;
70     int flags;
71     char str[1024];
72     int legacy_format;
73 };
74 
75 typedef struct SlirpState {
76     NetClientState nc;
77     QTAILQ_ENTRY(SlirpState) entry;
78     Slirp *slirp;
79 #ifndef _WIN32
80     char smb_dir[128];
81 #endif
82 } SlirpState;
83 
84 static struct slirp_config_str *slirp_configs;
85 const char *legacy_tftp_prefix;
86 const char *legacy_bootp_filename;
87 static QTAILQ_HEAD(slirp_stacks, SlirpState) slirp_stacks =
88     QTAILQ_HEAD_INITIALIZER(slirp_stacks);
89 
90 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
91                          int legacy_format);
92 static int slirp_guestfwd(SlirpState *s, const char *config_str,
93                           int legacy_format);
94 
95 #ifndef _WIN32
96 static const char *legacy_smb_export;
97 
98 static int slirp_smb(SlirpState *s, const char *exported_dir,
99                      struct in_addr vserver_addr);
100 static void slirp_smb_cleanup(SlirpState *s);
101 #else
102 static inline void slirp_smb_cleanup(SlirpState *s) { }
103 #endif
104 
105 void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)
106 {
107     SlirpState *s = opaque;
108 
109     qemu_send_packet(&s->nc, pkt, pkt_len);
110 }
111 
112 static ssize_t net_slirp_receive(NetClientState *nc, const uint8_t *buf, size_t size)
113 {
114     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
115 
116     slirp_input(s->slirp, buf, size);
117 
118     return size;
119 }
120 
121 static void net_slirp_cleanup(NetClientState *nc)
122 {
123     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
124 
125     slirp_cleanup(s->slirp);
126     slirp_smb_cleanup(s);
127     QTAILQ_REMOVE(&slirp_stacks, s, entry);
128 }
129 
130 static NetClientInfo net_slirp_info = {
131     .type = NET_CLIENT_OPTIONS_KIND_USER,
132     .size = sizeof(SlirpState),
133     .receive = net_slirp_receive,
134     .cleanup = net_slirp_cleanup,
135 };
136 
137 static int net_slirp_init(NetClientState *peer, const char *model,
138                           const char *name, int restricted,
139                           const char *vnetwork, const char *vhost,
140                           const char *vprefix6, int vprefix6_len,
141                           const char *vhost6,
142                           const char *vhostname, const char *tftp_export,
143                           const char *bootfile, const char *vdhcp_start,
144                           const char *vnameserver, const char *vnameserver6,
145                           const char *smb_export, const char *vsmbserver,
146                           const char **dnssearch)
147 {
148     /* default settings according to historic slirp */
149     struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */
150     struct in_addr mask = { .s_addr = htonl(0xffffff00) }; /* 255.255.255.0 */
151     struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
152     struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
153     struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
154     struct in6_addr ip6_prefix;
155     struct in6_addr ip6_host;
156     struct in6_addr ip6_dns;
157 #ifndef _WIN32
158     struct in_addr smbsrv = { .s_addr = 0 };
159 #endif
160     NetClientState *nc;
161     SlirpState *s;
162     char buf[20];
163     uint32_t addr;
164     int shift;
165     char *end;
166     struct slirp_config_str *config;
167 
168     if (!tftp_export) {
169         tftp_export = legacy_tftp_prefix;
170     }
171     if (!bootfile) {
172         bootfile = legacy_bootp_filename;
173     }
174 
175     if (vnetwork) {
176         if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
177             if (!inet_aton(vnetwork, &net)) {
178                 return -1;
179             }
180             addr = ntohl(net.s_addr);
181             if (!(addr & 0x80000000)) {
182                 mask.s_addr = htonl(0xff000000); /* class A */
183             } else if ((addr & 0xfff00000) == 0xac100000) {
184                 mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
185             } else if ((addr & 0xc0000000) == 0x80000000) {
186                 mask.s_addr = htonl(0xffff0000); /* class B */
187             } else if ((addr & 0xffff0000) == 0xc0a80000) {
188                 mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
189             } else if ((addr & 0xffff0000) == 0xc6120000) {
190                 mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
191             } else if ((addr & 0xe0000000) == 0xe0000000) {
192                 mask.s_addr = htonl(0xffffff00); /* class C */
193             } else {
194                 mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
195             }
196         } else {
197             if (!inet_aton(buf, &net)) {
198                 return -1;
199             }
200             shift = strtol(vnetwork, &end, 10);
201             if (*end != '\0') {
202                 if (!inet_aton(vnetwork, &mask)) {
203                     return -1;
204                 }
205             } else if (shift < 4 || shift > 32) {
206                 return -1;
207             } else {
208                 mask.s_addr = htonl(0xffffffff << (32 - shift));
209             }
210         }
211         net.s_addr &= mask.s_addr;
212         host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
213         dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
214         dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
215     }
216 
217     if (vhost && !inet_aton(vhost, &host)) {
218         return -1;
219     }
220     if ((host.s_addr & mask.s_addr) != net.s_addr) {
221         return -1;
222     }
223 
224     if (vnameserver && !inet_aton(vnameserver, &dns)) {
225         return -1;
226     }
227     if ((dns.s_addr & mask.s_addr) != net.s_addr ||
228         dns.s_addr == host.s_addr) {
229         return -1;
230     }
231 
232     if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
233         return -1;
234     }
235     if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
236         dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
237         return -1;
238     }
239 
240 #ifndef _WIN32
241     if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
242         return -1;
243     }
244 #endif
245 
246 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
247     /* No inet_pton helper before Vista... */
248     if (vprefix6) {
249         /* Unsupported */
250         return -1;
251     }
252     memset(&ip6_prefix, 0, sizeof(ip6_prefix));
253     ip6_prefix.s6_addr[0] = 0xfe;
254     ip6_prefix.s6_addr[1] = 0xc0;
255 #else
256     if (!vprefix6) {
257         vprefix6 = "fec0::";
258     }
259     if (!inet_pton(AF_INET6, vprefix6, &ip6_prefix)) {
260         return -1;
261     }
262 #endif
263 
264     if (!vprefix6_len) {
265         vprefix6_len = 64;
266     }
267     if (vprefix6_len < 0 || vprefix6_len > 126) {
268         return -1;
269     }
270 
271     if (vhost6) {
272 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
273         return -1;
274 #else
275         if (!inet_pton(AF_INET6, vhost6, &ip6_host)) {
276             return -1;
277         }
278         if (!in6_equal_net(&ip6_prefix, &ip6_host, vprefix6_len)) {
279             return -1;
280         }
281 #endif
282     } else {
283         ip6_host = ip6_prefix;
284         ip6_host.s6_addr[15] |= 2;
285     }
286 
287     if (vnameserver6) {
288 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
289         return -1;
290 #else
291         if (!inet_pton(AF_INET6, vnameserver6, &ip6_dns)) {
292             return -1;
293         }
294         if (!in6_equal_net(&ip6_prefix, &ip6_dns, vprefix6_len)) {
295             return -1;
296         }
297 #endif
298     } else {
299         ip6_dns = ip6_prefix;
300         ip6_dns.s6_addr[15] |= 3;
301     }
302 
303 
304     nc = qemu_new_net_client(&net_slirp_info, peer, model, name);
305 
306     snprintf(nc->info_str, sizeof(nc->info_str),
307              "net=%s,restrict=%s", inet_ntoa(net),
308              restricted ? "on" : "off");
309 
310     s = DO_UPCAST(SlirpState, nc, nc);
311 
312     s->slirp = slirp_init(restricted, net, mask, host,
313                           ip6_prefix, vprefix6_len, ip6_host,
314                           vhostname, tftp_export, bootfile, dhcp,
315                           dns, ip6_dns, dnssearch, s);
316     QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);
317 
318     for (config = slirp_configs; config; config = config->next) {
319         if (config->flags & SLIRP_CFG_HOSTFWD) {
320             if (slirp_hostfwd(s, config->str,
321                               config->flags & SLIRP_CFG_LEGACY) < 0)
322                 goto error;
323         } else {
324             if (slirp_guestfwd(s, config->str,
325                                config->flags & SLIRP_CFG_LEGACY) < 0)
326                 goto error;
327         }
328     }
329 #ifndef _WIN32
330     if (!smb_export) {
331         smb_export = legacy_smb_export;
332     }
333     if (smb_export) {
334         if (slirp_smb(s, smb_export, smbsrv) < 0)
335             goto error;
336     }
337 #endif
338 
339     return 0;
340 
341 error:
342     qemu_del_net_client(nc);
343     return -1;
344 }
345 
346 static SlirpState *slirp_lookup(Monitor *mon, const char *vlan,
347                                 const char *stack)
348 {
349 
350     if (vlan) {
351         NetClientState *nc;
352         nc = net_hub_find_client_by_name(strtol(vlan, NULL, 0), stack);
353         if (!nc) {
354             monitor_printf(mon, "unrecognized (vlan-id, stackname) pair\n");
355             return NULL;
356         }
357         if (strcmp(nc->model, "user")) {
358             monitor_printf(mon, "invalid device specified\n");
359             return NULL;
360         }
361         return DO_UPCAST(SlirpState, nc, nc);
362     } else {
363         if (QTAILQ_EMPTY(&slirp_stacks)) {
364             monitor_printf(mon, "user mode network stack not in use\n");
365             return NULL;
366         }
367         return QTAILQ_FIRST(&slirp_stacks);
368     }
369 }
370 
371 void hmp_hostfwd_remove(Monitor *mon, const QDict *qdict)
372 {
373     struct in_addr host_addr = { .s_addr = INADDR_ANY };
374     int host_port;
375     char buf[256];
376     const char *src_str, *p;
377     SlirpState *s;
378     int is_udp = 0;
379     int err;
380     const char *arg1 = qdict_get_str(qdict, "arg1");
381     const char *arg2 = qdict_get_try_str(qdict, "arg2");
382     const char *arg3 = qdict_get_try_str(qdict, "arg3");
383 
384     if (arg2) {
385         s = slirp_lookup(mon, arg1, arg2);
386         src_str = arg3;
387     } else {
388         s = slirp_lookup(mon, NULL, NULL);
389         src_str = arg1;
390     }
391     if (!s) {
392         return;
393     }
394 
395     p = src_str;
396     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
397         goto fail_syntax;
398     }
399 
400     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
401         is_udp = 0;
402     } else if (!strcmp(buf, "udp")) {
403         is_udp = 1;
404     } else {
405         goto fail_syntax;
406     }
407 
408     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
409         goto fail_syntax;
410     }
411     if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
412         goto fail_syntax;
413     }
414 
415     host_port = atoi(p);
416 
417     err = slirp_remove_hostfwd(s->slirp, is_udp, host_addr, host_port);
418 
419     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
420                    err ? "not found" : "removed");
421     return;
422 
423  fail_syntax:
424     monitor_printf(mon, "invalid format\n");
425 }
426 
427 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
428                          int legacy_format)
429 {
430     struct in_addr host_addr = { .s_addr = INADDR_ANY };
431     struct in_addr guest_addr = { .s_addr = 0 };
432     int host_port, guest_port;
433     const char *p;
434     char buf[256];
435     int is_udp;
436     char *end;
437 
438     p = redir_str;
439     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
440         goto fail_syntax;
441     }
442     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
443         is_udp = 0;
444     } else if (!strcmp(buf, "udp")) {
445         is_udp = 1;
446     } else {
447         goto fail_syntax;
448     }
449 
450     if (!legacy_format) {
451         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
452             goto fail_syntax;
453         }
454         if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
455             goto fail_syntax;
456         }
457     }
458 
459     if (get_str_sep(buf, sizeof(buf), &p, legacy_format ? ':' : '-') < 0) {
460         goto fail_syntax;
461     }
462     host_port = strtol(buf, &end, 0);
463     if (*end != '\0' || host_port < 1 || host_port > 65535) {
464         goto fail_syntax;
465     }
466 
467     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
468         goto fail_syntax;
469     }
470     if (buf[0] != '\0' && !inet_aton(buf, &guest_addr)) {
471         goto fail_syntax;
472     }
473 
474     guest_port = strtol(p, &end, 0);
475     if (*end != '\0' || guest_port < 1 || guest_port > 65535) {
476         goto fail_syntax;
477     }
478 
479     if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,
480                           guest_port) < 0) {
481         error_report("could not set up host forwarding rule '%s'",
482                      redir_str);
483         return -1;
484     }
485     return 0;
486 
487  fail_syntax:
488     error_report("invalid host forwarding rule '%s'", redir_str);
489     return -1;
490 }
491 
492 void hmp_hostfwd_add(Monitor *mon, const QDict *qdict)
493 {
494     const char *redir_str;
495     SlirpState *s;
496     const char *arg1 = qdict_get_str(qdict, "arg1");
497     const char *arg2 = qdict_get_try_str(qdict, "arg2");
498     const char *arg3 = qdict_get_try_str(qdict, "arg3");
499 
500     if (arg2) {
501         s = slirp_lookup(mon, arg1, arg2);
502         redir_str = arg3;
503     } else {
504         s = slirp_lookup(mon, NULL, NULL);
505         redir_str = arg1;
506     }
507     if (s) {
508         slirp_hostfwd(s, redir_str, 0);
509     }
510 
511 }
512 
513 int net_slirp_redir(const char *redir_str)
514 {
515     struct slirp_config_str *config;
516 
517     if (QTAILQ_EMPTY(&slirp_stacks)) {
518         config = g_malloc(sizeof(*config));
519         pstrcpy(config->str, sizeof(config->str), redir_str);
520         config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;
521         config->next = slirp_configs;
522         slirp_configs = config;
523         return 0;
524     }
525 
526     return slirp_hostfwd(QTAILQ_FIRST(&slirp_stacks), redir_str, 1);
527 }
528 
529 #ifndef _WIN32
530 
531 /* automatic user mode samba server configuration */
532 static void slirp_smb_cleanup(SlirpState *s)
533 {
534     char cmd[128];
535     int ret;
536 
537     if (s->smb_dir[0] != '\0') {
538         snprintf(cmd, sizeof(cmd), "rm -rf %s", s->smb_dir);
539         ret = system(cmd);
540         if (ret == -1 || !WIFEXITED(ret)) {
541             error_report("'%s' failed.", cmd);
542         } else if (WEXITSTATUS(ret)) {
543             error_report("'%s' failed. Error code: %d",
544                          cmd, WEXITSTATUS(ret));
545         }
546         s->smb_dir[0] = '\0';
547     }
548 }
549 
550 static int slirp_smb(SlirpState* s, const char *exported_dir,
551                      struct in_addr vserver_addr)
552 {
553     char smb_conf[128];
554     char smb_cmdline[128];
555     struct passwd *passwd;
556     FILE *f;
557 
558     passwd = getpwuid(geteuid());
559     if (!passwd) {
560         error_report("failed to retrieve user name");
561         return -1;
562     }
563 
564     if (access(CONFIG_SMBD_COMMAND, F_OK)) {
565         error_report("could not find '%s', please install it",
566                      CONFIG_SMBD_COMMAND);
567         return -1;
568     }
569 
570     if (access(exported_dir, R_OK | X_OK)) {
571         error_report("error accessing shared directory '%s': %s",
572                      exported_dir, strerror(errno));
573         return -1;
574     }
575 
576     snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.XXXXXX");
577     if (!mkdtemp(s->smb_dir)) {
578         error_report("could not create samba server dir '%s'", s->smb_dir);
579         s->smb_dir[0] = 0;
580         return -1;
581     }
582     snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");
583 
584     f = fopen(smb_conf, "w");
585     if (!f) {
586         slirp_smb_cleanup(s);
587         error_report("could not create samba server configuration file '%s'",
588                      smb_conf);
589         return -1;
590     }
591     fprintf(f,
592             "[global]\n"
593             "private dir=%s\n"
594             "interfaces=127.0.0.1\n"
595             "bind interfaces only=yes\n"
596             "pid directory=%s\n"
597             "lock directory=%s\n"
598             "state directory=%s\n"
599             "cache directory=%s\n"
600             "ncalrpc dir=%s/ncalrpc\n"
601             "log file=%s/log.smbd\n"
602             "smb passwd file=%s/smbpasswd\n"
603             "security = user\n"
604             "map to guest = Bad User\n"
605             "load printers = no\n"
606             "printing = bsd\n"
607             "disable spoolss = yes\n"
608             "usershare max shares = 0\n"
609             "[qemu]\n"
610             "path=%s\n"
611             "read only=no\n"
612             "guest ok=yes\n"
613             "force user=%s\n",
614             s->smb_dir,
615             s->smb_dir,
616             s->smb_dir,
617             s->smb_dir,
618             s->smb_dir,
619             s->smb_dir,
620             s->smb_dir,
621             s->smb_dir,
622             exported_dir,
623             passwd->pw_name
624             );
625     fclose(f);
626 
627     snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -l %s -s %s",
628              CONFIG_SMBD_COMMAND, s->smb_dir, smb_conf);
629 
630     if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0 ||
631         slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 445) < 0) {
632         slirp_smb_cleanup(s);
633         error_report("conflicting/invalid smbserver address");
634         return -1;
635     }
636     return 0;
637 }
638 
639 /* automatic user mode samba server configuration (legacy interface) */
640 int net_slirp_smb(const char *exported_dir)
641 {
642     struct in_addr vserver_addr = { .s_addr = 0 };
643 
644     if (legacy_smb_export) {
645         fprintf(stderr, "-smb given twice\n");
646         return -1;
647     }
648     legacy_smb_export = exported_dir;
649     if (!QTAILQ_EMPTY(&slirp_stacks)) {
650         return slirp_smb(QTAILQ_FIRST(&slirp_stacks), exported_dir,
651                          vserver_addr);
652     }
653     return 0;
654 }
655 
656 #endif /* !defined(_WIN32) */
657 
658 struct GuestFwd {
659     CharDriverState *hd;
660     struct in_addr server;
661     int port;
662     Slirp *slirp;
663 };
664 
665 static int guestfwd_can_read(void *opaque)
666 {
667     struct GuestFwd *fwd = opaque;
668     return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);
669 }
670 
671 static void guestfwd_read(void *opaque, const uint8_t *buf, int size)
672 {
673     struct GuestFwd *fwd = opaque;
674     slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);
675 }
676 
677 static int slirp_guestfwd(SlirpState *s, const char *config_str,
678                           int legacy_format)
679 {
680     struct in_addr server = { .s_addr = 0 };
681     struct GuestFwd *fwd;
682     const char *p;
683     char buf[128];
684     char *end;
685     int port;
686 
687     p = config_str;
688     if (legacy_format) {
689         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
690             goto fail_syntax;
691         }
692     } else {
693         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
694             goto fail_syntax;
695         }
696         if (strcmp(buf, "tcp") && buf[0] != '\0') {
697             goto fail_syntax;
698         }
699         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
700             goto fail_syntax;
701         }
702         if (buf[0] != '\0' && !inet_aton(buf, &server)) {
703             goto fail_syntax;
704         }
705         if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
706             goto fail_syntax;
707         }
708     }
709     port = strtol(buf, &end, 10);
710     if (*end != '\0' || port < 1 || port > 65535) {
711         goto fail_syntax;
712     }
713 
714     snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port);
715 
716     if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) {
717         if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) {
718             error_report("conflicting/invalid host:port in guest forwarding "
719                          "rule '%s'", config_str);
720             return -1;
721         }
722     } else {
723         fwd = g_new(struct GuestFwd, 1);
724         fwd->hd = qemu_chr_new(buf, p, NULL);
725         if (!fwd->hd) {
726             error_report("could not open guest forwarding device '%s'", buf);
727             g_free(fwd);
728             return -1;
729         }
730 
731         if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) {
732             error_report("conflicting/invalid host:port in guest forwarding "
733                          "rule '%s'", config_str);
734             g_free(fwd);
735             return -1;
736         }
737         fwd->server = server;
738         fwd->port = port;
739         fwd->slirp = s->slirp;
740 
741         qemu_chr_fe_claim_no_fail(fwd->hd);
742         qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read,
743                               NULL, fwd);
744     }
745     return 0;
746 
747  fail_syntax:
748     error_report("invalid guest forwarding rule '%s'", config_str);
749     return -1;
750 }
751 
752 void hmp_info_usernet(Monitor *mon, const QDict *qdict)
753 {
754     SlirpState *s;
755 
756     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
757         int id;
758         bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;
759         monitor_printf(mon, "VLAN %d (%s):\n",
760                        got_vlan_id ? id : -1,
761                        s->nc.name);
762         slirp_connection_info(s->slirp, mon);
763     }
764 }
765 
766 static void
767 net_init_slirp_configs(const StringList *fwd, int flags)
768 {
769     while (fwd) {
770         struct slirp_config_str *config;
771 
772         config = g_malloc0(sizeof(*config));
773         pstrcpy(config->str, sizeof(config->str), fwd->value->str);
774         config->flags = flags;
775         config->next = slirp_configs;
776         slirp_configs = config;
777 
778         fwd = fwd->next;
779     }
780 }
781 
782 static const char **slirp_dnssearch(const StringList *dnsname)
783 {
784     const StringList *c = dnsname;
785     size_t i = 0, num_opts = 0;
786     const char **ret;
787 
788     while (c) {
789         num_opts++;
790         c = c->next;
791     }
792 
793     if (num_opts == 0) {
794         return NULL;
795     }
796 
797     ret = g_malloc((num_opts + 1) * sizeof(*ret));
798     c = dnsname;
799     while (c) {
800         ret[i++] = c->value->str;
801         c = c->next;
802     }
803     ret[i] = NULL;
804     return ret;
805 }
806 
807 int net_init_slirp(const NetClientOptions *opts, const char *name,
808                    NetClientState *peer, Error **errp)
809 {
810     /* FIXME error_setg(errp, ...) on failure */
811     struct slirp_config_str *config;
812     char *vnet;
813     int ret;
814     const NetdevUserOptions *user;
815     const char **dnssearch;
816 
817     assert(opts->type == NET_CLIENT_OPTIONS_KIND_USER);
818     user = opts->u.user.data;
819 
820     vnet = user->has_net ? g_strdup(user->net) :
821            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
822            NULL;
823 
824     dnssearch = slirp_dnssearch(user->dnssearch);
825 
826     /* all optional fields are initialized to "all bits zero" */
827 
828     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
829     net_init_slirp_configs(user->guestfwd, 0);
830 
831     ret = net_slirp_init(peer, "user", name, user->q_restrict, vnet,
832                          user->host, user->ip6_prefix, user->ip6_prefixlen,
833                          user->ip6_host, user->hostname, user->tftp,
834                          user->bootfile, user->dhcpstart,
835                          user->dns, user->ip6_dns, user->smb,
836                          user->smbserver, dnssearch);
837 
838     while (slirp_configs) {
839         config = slirp_configs;
840         slirp_configs = config->next;
841         g_free(config);
842     }
843 
844     g_free(vnet);
845     g_free(dnssearch);
846 
847     return ret;
848 }
849 
850 int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)
851 {
852     if (strcmp(opts_list->name, "net") != 0 ||
853         strncmp(optarg, "channel,", strlen("channel,")) != 0) {
854         return 0;
855     }
856 
857     error_report("The '-net channel' option is deprecated. "
858                  "Please use '-netdev user,guestfwd=...' instead.");
859 
860     /* handle legacy -net channel,port:chr */
861     optarg += strlen("channel,");
862 
863     if (QTAILQ_EMPTY(&slirp_stacks)) {
864         struct slirp_config_str *config;
865 
866         config = g_malloc(sizeof(*config));
867         pstrcpy(config->str, sizeof(config->str), optarg);
868         config->flags = SLIRP_CFG_LEGACY;
869         config->next = slirp_configs;
870         slirp_configs = config;
871         *ret = 0;
872     } else {
873         *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);
874     }
875 
876     return 1;
877 }
878 
879