xref: /qemu/net/slirp.c (revision bc35d510) 
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 "sysemu/sysemu.h"
42 #include "qemu/cutils.h"
43 
44 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
45 {
46     const char *p, *p1;
47     int len;
48     p = *pp;
49     p1 = strchr(p, sep);
50     if (!p1)
51         return -1;
52     len = p1 - p;
53     p1++;
54     if (buf_size > 0) {
55         if (len > buf_size - 1)
56             len = buf_size - 1;
57         memcpy(buf, p, len);
58         buf[len] = '\0';
59     }
60     *pp = p1;
61     return 0;
62 }
63 
64 /* slirp network adapter */
65 
66 #define SLIRP_CFG_HOSTFWD 1
67 #define SLIRP_CFG_LEGACY  2
68 
69 struct slirp_config_str {
70     struct slirp_config_str *next;
71     int flags;
72     char str[1024];
73     int legacy_format;
74 };
75 
76 typedef struct SlirpState {
77     NetClientState nc;
78     QTAILQ_ENTRY(SlirpState) entry;
79     Slirp *slirp;
80     Notifier exit_notifier;
81 #ifndef _WIN32
82     char smb_dir[128];
83 #endif
84 } SlirpState;
85 
86 static struct slirp_config_str *slirp_configs;
87 const char *legacy_tftp_prefix;
88 const char *legacy_bootp_filename;
89 static QTAILQ_HEAD(slirp_stacks, SlirpState) slirp_stacks =
90     QTAILQ_HEAD_INITIALIZER(slirp_stacks);
91 
92 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
93                          int legacy_format);
94 static int slirp_guestfwd(SlirpState *s, const char *config_str,
95                           int legacy_format);
96 
97 #ifndef _WIN32
98 static const char *legacy_smb_export;
99 
100 static int slirp_smb(SlirpState *s, const char *exported_dir,
101                      struct in_addr vserver_addr);
102 static void slirp_smb_cleanup(SlirpState *s);
103 #else
104 static inline void slirp_smb_cleanup(SlirpState *s) { }
105 #endif
106 
107 void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)
108 {
109     SlirpState *s = opaque;
110 
111     qemu_send_packet(&s->nc, pkt, pkt_len);
112 }
113 
114 static ssize_t net_slirp_receive(NetClientState *nc, const uint8_t *buf, size_t size)
115 {
116     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
117 
118     slirp_input(s->slirp, buf, size);
119 
120     return size;
121 }
122 
123 static void slirp_smb_exit(Notifier *n, void *data)
124 {
125     SlirpState *s = container_of(n, SlirpState, exit_notifier);
126     slirp_smb_cleanup(s);
127 }
128 
129 static void net_slirp_cleanup(NetClientState *nc)
130 {
131     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
132 
133     slirp_cleanup(s->slirp);
134     qemu_remove_exit_notifier(&s->exit_notifier);
135     slirp_smb_cleanup(s);
136     QTAILQ_REMOVE(&slirp_stacks, s, entry);
137 }
138 
139 static NetClientInfo net_slirp_info = {
140     .type = NET_CLIENT_DRIVER_USER,
141     .size = sizeof(SlirpState),
142     .receive = net_slirp_receive,
143     .cleanup = net_slirp_cleanup,
144 };
145 
146 static int net_slirp_init(NetClientState *peer, const char *model,
147                           const char *name, int restricted,
148                           bool ipv4, const char *vnetwork, const char *vhost,
149                           bool ipv6, const char *vprefix6, int vprefix6_len,
150                           const char *vhost6,
151                           const char *vhostname, const char *tftp_export,
152                           const char *bootfile, const char *vdhcp_start,
153                           const char *vnameserver, const char *vnameserver6,
154                           const char *smb_export, const char *vsmbserver,
155                           const char **dnssearch)
156 {
157     /* default settings according to historic slirp */
158     struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */
159     struct in_addr mask = { .s_addr = htonl(0xffffff00) }; /* 255.255.255.0 */
160     struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
161     struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
162     struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
163     struct in6_addr ip6_prefix;
164     struct in6_addr ip6_host;
165     struct in6_addr ip6_dns;
166 #ifndef _WIN32
167     struct in_addr smbsrv = { .s_addr = 0 };
168 #endif
169     NetClientState *nc;
170     SlirpState *s;
171     char buf[20];
172     uint32_t addr;
173     int shift;
174     char *end;
175     struct slirp_config_str *config;
176 
177     if (!ipv4 && (vnetwork || vhost || vnameserver)) {
178         return -1;
179     }
180 
181     if (!ipv6 && (vprefix6 || vhost6 || vnameserver6)) {
182         return -1;
183     }
184 
185     if (!ipv4 && !ipv6) {
186         /* It doesn't make sense to disable both */
187         return -1;
188     }
189 
190     if (!tftp_export) {
191         tftp_export = legacy_tftp_prefix;
192     }
193     if (!bootfile) {
194         bootfile = legacy_bootp_filename;
195     }
196 
197     if (vnetwork) {
198         if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
199             if (!inet_aton(vnetwork, &net)) {
200                 return -1;
201             }
202             addr = ntohl(net.s_addr);
203             if (!(addr & 0x80000000)) {
204                 mask.s_addr = htonl(0xff000000); /* class A */
205             } else if ((addr & 0xfff00000) == 0xac100000) {
206                 mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
207             } else if ((addr & 0xc0000000) == 0x80000000) {
208                 mask.s_addr = htonl(0xffff0000); /* class B */
209             } else if ((addr & 0xffff0000) == 0xc0a80000) {
210                 mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
211             } else if ((addr & 0xffff0000) == 0xc6120000) {
212                 mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
213             } else if ((addr & 0xe0000000) == 0xe0000000) {
214                 mask.s_addr = htonl(0xffffff00); /* class C */
215             } else {
216                 mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
217             }
218         } else {
219             if (!inet_aton(buf, &net)) {
220                 return -1;
221             }
222             shift = strtol(vnetwork, &end, 10);
223             if (*end != '\0') {
224                 if (!inet_aton(vnetwork, &mask)) {
225                     return -1;
226                 }
227             } else if (shift < 4 || shift > 32) {
228                 return -1;
229             } else {
230                 mask.s_addr = htonl(0xffffffff << (32 - shift));
231             }
232         }
233         net.s_addr &= mask.s_addr;
234         host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
235         dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
236         dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
237     }
238 
239     if (vhost && !inet_aton(vhost, &host)) {
240         return -1;
241     }
242     if ((host.s_addr & mask.s_addr) != net.s_addr) {
243         return -1;
244     }
245 
246     if (vnameserver && !inet_aton(vnameserver, &dns)) {
247         return -1;
248     }
249     if ((dns.s_addr & mask.s_addr) != net.s_addr ||
250         dns.s_addr == host.s_addr) {
251         return -1;
252     }
253 
254     if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
255         return -1;
256     }
257     if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
258         dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
259         return -1;
260     }
261 
262 #ifndef _WIN32
263     if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
264         return -1;
265     }
266 #endif
267 
268 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
269     /* No inet_pton helper before Vista... */
270     if (vprefix6) {
271         /* Unsupported */
272         return -1;
273     }
274     memset(&ip6_prefix, 0, sizeof(ip6_prefix));
275     ip6_prefix.s6_addr[0] = 0xfe;
276     ip6_prefix.s6_addr[1] = 0xc0;
277 #else
278     if (!vprefix6) {
279         vprefix6 = "fec0::";
280     }
281     if (!inet_pton(AF_INET6, vprefix6, &ip6_prefix)) {
282         return -1;
283     }
284 #endif
285 
286     if (!vprefix6_len) {
287         vprefix6_len = 64;
288     }
289     if (vprefix6_len < 0 || vprefix6_len > 126) {
290         return -1;
291     }
292 
293     if (vhost6) {
294 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
295         return -1;
296 #else
297         if (!inet_pton(AF_INET6, vhost6, &ip6_host)) {
298             return -1;
299         }
300         if (!in6_equal_net(&ip6_prefix, &ip6_host, vprefix6_len)) {
301             return -1;
302         }
303 #endif
304     } else {
305         ip6_host = ip6_prefix;
306         ip6_host.s6_addr[15] |= 2;
307     }
308 
309     if (vnameserver6) {
310 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
311         return -1;
312 #else
313         if (!inet_pton(AF_INET6, vnameserver6, &ip6_dns)) {
314             return -1;
315         }
316         if (!in6_equal_net(&ip6_prefix, &ip6_dns, vprefix6_len)) {
317             return -1;
318         }
319 #endif
320     } else {
321         ip6_dns = ip6_prefix;
322         ip6_dns.s6_addr[15] |= 3;
323     }
324 
325 
326     nc = qemu_new_net_client(&net_slirp_info, peer, model, name);
327 
328     snprintf(nc->info_str, sizeof(nc->info_str),
329              "net=%s,restrict=%s", inet_ntoa(net),
330              restricted ? "on" : "off");
331 
332     s = DO_UPCAST(SlirpState, nc, nc);
333 
334     s->slirp = slirp_init(restricted, ipv4, net, mask, host,
335                           ipv6, ip6_prefix, vprefix6_len, ip6_host,
336                           vhostname, tftp_export, bootfile, dhcp,
337                           dns, ip6_dns, dnssearch, s);
338     QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);
339 
340     for (config = slirp_configs; config; config = config->next) {
341         if (config->flags & SLIRP_CFG_HOSTFWD) {
342             if (slirp_hostfwd(s, config->str,
343                               config->flags & SLIRP_CFG_LEGACY) < 0)
344                 goto error;
345         } else {
346             if (slirp_guestfwd(s, config->str,
347                                config->flags & SLIRP_CFG_LEGACY) < 0)
348                 goto error;
349         }
350     }
351 #ifndef _WIN32
352     if (!smb_export) {
353         smb_export = legacy_smb_export;
354     }
355     if (smb_export) {
356         if (slirp_smb(s, smb_export, smbsrv) < 0)
357             goto error;
358     }
359 #endif
360 
361     s->exit_notifier.notify = slirp_smb_exit;
362     qemu_add_exit_notifier(&s->exit_notifier);
363     return 0;
364 
365 error:
366     qemu_del_net_client(nc);
367     return -1;
368 }
369 
370 static SlirpState *slirp_lookup(Monitor *mon, const char *vlan,
371                                 const char *stack)
372 {
373 
374     if (vlan) {
375         NetClientState *nc;
376         nc = net_hub_find_client_by_name(strtol(vlan, NULL, 0), stack);
377         if (!nc) {
378             monitor_printf(mon, "unrecognized (vlan-id, stackname) pair\n");
379             return NULL;
380         }
381         if (strcmp(nc->model, "user")) {
382             monitor_printf(mon, "invalid device specified\n");
383             return NULL;
384         }
385         return DO_UPCAST(SlirpState, nc, nc);
386     } else {
387         if (QTAILQ_EMPTY(&slirp_stacks)) {
388             monitor_printf(mon, "user mode network stack not in use\n");
389             return NULL;
390         }
391         return QTAILQ_FIRST(&slirp_stacks);
392     }
393 }
394 
395 void hmp_hostfwd_remove(Monitor *mon, const QDict *qdict)
396 {
397     struct in_addr host_addr = { .s_addr = INADDR_ANY };
398     int host_port;
399     char buf[256];
400     const char *src_str, *p;
401     SlirpState *s;
402     int is_udp = 0;
403     int err;
404     const char *arg1 = qdict_get_str(qdict, "arg1");
405     const char *arg2 = qdict_get_try_str(qdict, "arg2");
406     const char *arg3 = qdict_get_try_str(qdict, "arg3");
407 
408     if (arg2) {
409         s = slirp_lookup(mon, arg1, arg2);
410         src_str = arg3;
411     } else {
412         s = slirp_lookup(mon, NULL, NULL);
413         src_str = arg1;
414     }
415     if (!s) {
416         return;
417     }
418 
419     p = src_str;
420     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
421         goto fail_syntax;
422     }
423 
424     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
425         is_udp = 0;
426     } else if (!strcmp(buf, "udp")) {
427         is_udp = 1;
428     } else {
429         goto fail_syntax;
430     }
431 
432     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
433         goto fail_syntax;
434     }
435     if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
436         goto fail_syntax;
437     }
438 
439     host_port = atoi(p);
440 
441     err = slirp_remove_hostfwd(s->slirp, is_udp, host_addr, host_port);
442 
443     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
444                    err ? "not found" : "removed");
445     return;
446 
447  fail_syntax:
448     monitor_printf(mon, "invalid format\n");
449 }
450 
451 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
452                          int legacy_format)
453 {
454     struct in_addr host_addr = { .s_addr = INADDR_ANY };
455     struct in_addr guest_addr = { .s_addr = 0 };
456     int host_port, guest_port;
457     const char *p;
458     char buf[256];
459     int is_udp;
460     char *end;
461 
462     p = redir_str;
463     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
464         goto fail_syntax;
465     }
466     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
467         is_udp = 0;
468     } else if (!strcmp(buf, "udp")) {
469         is_udp = 1;
470     } else {
471         goto fail_syntax;
472     }
473 
474     if (!legacy_format) {
475         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
476             goto fail_syntax;
477         }
478         if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
479             goto fail_syntax;
480         }
481     }
482 
483     if (get_str_sep(buf, sizeof(buf), &p, legacy_format ? ':' : '-') < 0) {
484         goto fail_syntax;
485     }
486     host_port = strtol(buf, &end, 0);
487     if (*end != '\0' || host_port < 1 || host_port > 65535) {
488         goto fail_syntax;
489     }
490 
491     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
492         goto fail_syntax;
493     }
494     if (buf[0] != '\0' && !inet_aton(buf, &guest_addr)) {
495         goto fail_syntax;
496     }
497 
498     guest_port = strtol(p, &end, 0);
499     if (*end != '\0' || guest_port < 1 || guest_port > 65535) {
500         goto fail_syntax;
501     }
502 
503     if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,
504                           guest_port) < 0) {
505         error_report("could not set up host forwarding rule '%s'",
506                      redir_str);
507         return -1;
508     }
509     return 0;
510 
511  fail_syntax:
512     error_report("invalid host forwarding rule '%s'", redir_str);
513     return -1;
514 }
515 
516 void hmp_hostfwd_add(Monitor *mon, const QDict *qdict)
517 {
518     const char *redir_str;
519     SlirpState *s;
520     const char *arg1 = qdict_get_str(qdict, "arg1");
521     const char *arg2 = qdict_get_try_str(qdict, "arg2");
522     const char *arg3 = qdict_get_try_str(qdict, "arg3");
523 
524     if (arg2) {
525         s = slirp_lookup(mon, arg1, arg2);
526         redir_str = arg3;
527     } else {
528         s = slirp_lookup(mon, NULL, NULL);
529         redir_str = arg1;
530     }
531     if (s) {
532         slirp_hostfwd(s, redir_str, 0);
533     }
534 
535 }
536 
537 int net_slirp_redir(const char *redir_str)
538 {
539     struct slirp_config_str *config;
540 
541     if (QTAILQ_EMPTY(&slirp_stacks)) {
542         config = g_malloc(sizeof(*config));
543         pstrcpy(config->str, sizeof(config->str), redir_str);
544         config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;
545         config->next = slirp_configs;
546         slirp_configs = config;
547         return 0;
548     }
549 
550     return slirp_hostfwd(QTAILQ_FIRST(&slirp_stacks), redir_str, 1);
551 }
552 
553 #ifndef _WIN32
554 
555 /* automatic user mode samba server configuration */
556 static void slirp_smb_cleanup(SlirpState *s)
557 {
558     char cmd[128];
559     int ret;
560 
561     if (s->smb_dir[0] != '\0') {
562         snprintf(cmd, sizeof(cmd), "rm -rf %s", s->smb_dir);
563         ret = system(cmd);
564         if (ret == -1 || !WIFEXITED(ret)) {
565             error_report("'%s' failed.", cmd);
566         } else if (WEXITSTATUS(ret)) {
567             error_report("'%s' failed. Error code: %d",
568                          cmd, WEXITSTATUS(ret));
569         }
570         s->smb_dir[0] = '\0';
571     }
572 }
573 
574 static int slirp_smb(SlirpState* s, const char *exported_dir,
575                      struct in_addr vserver_addr)
576 {
577     char smb_conf[128];
578     char smb_cmdline[128];
579     struct passwd *passwd;
580     FILE *f;
581 
582     passwd = getpwuid(geteuid());
583     if (!passwd) {
584         error_report("failed to retrieve user name");
585         return -1;
586     }
587 
588     if (access(CONFIG_SMBD_COMMAND, F_OK)) {
589         error_report("could not find '%s', please install it",
590                      CONFIG_SMBD_COMMAND);
591         return -1;
592     }
593 
594     if (access(exported_dir, R_OK | X_OK)) {
595         error_report("error accessing shared directory '%s': %s",
596                      exported_dir, strerror(errno));
597         return -1;
598     }
599 
600     snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.XXXXXX");
601     if (!mkdtemp(s->smb_dir)) {
602         error_report("could not create samba server dir '%s'", s->smb_dir);
603         s->smb_dir[0] = 0;
604         return -1;
605     }
606     snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");
607 
608     f = fopen(smb_conf, "w");
609     if (!f) {
610         slirp_smb_cleanup(s);
611         error_report("could not create samba server configuration file '%s'",
612                      smb_conf);
613         return -1;
614     }
615     fprintf(f,
616             "[global]\n"
617             "private dir=%s\n"
618             "interfaces=127.0.0.1\n"
619             "bind interfaces only=yes\n"
620             "pid directory=%s\n"
621             "lock directory=%s\n"
622             "state directory=%s\n"
623             "cache directory=%s\n"
624             "ncalrpc dir=%s/ncalrpc\n"
625             "log file=%s/log.smbd\n"
626             "smb passwd file=%s/smbpasswd\n"
627             "security = user\n"
628             "map to guest = Bad User\n"
629             "load printers = no\n"
630             "printing = bsd\n"
631             "disable spoolss = yes\n"
632             "usershare max shares = 0\n"
633             "[qemu]\n"
634             "path=%s\n"
635             "read only=no\n"
636             "guest ok=yes\n"
637             "force user=%s\n",
638             s->smb_dir,
639             s->smb_dir,
640             s->smb_dir,
641             s->smb_dir,
642             s->smb_dir,
643             s->smb_dir,
644             s->smb_dir,
645             s->smb_dir,
646             exported_dir,
647             passwd->pw_name
648             );
649     fclose(f);
650 
651     snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -l %s -s %s",
652              CONFIG_SMBD_COMMAND, s->smb_dir, smb_conf);
653 
654     if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0 ||
655         slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 445) < 0) {
656         slirp_smb_cleanup(s);
657         error_report("conflicting/invalid smbserver address");
658         return -1;
659     }
660     return 0;
661 }
662 
663 /* automatic user mode samba server configuration (legacy interface) */
664 int net_slirp_smb(const char *exported_dir)
665 {
666     struct in_addr vserver_addr = { .s_addr = 0 };
667 
668     if (legacy_smb_export) {
669         fprintf(stderr, "-smb given twice\n");
670         return -1;
671     }
672     legacy_smb_export = exported_dir;
673     if (!QTAILQ_EMPTY(&slirp_stacks)) {
674         return slirp_smb(QTAILQ_FIRST(&slirp_stacks), exported_dir,
675                          vserver_addr);
676     }
677     return 0;
678 }
679 
680 #endif /* !defined(_WIN32) */
681 
682 struct GuestFwd {
683     CharDriverState *hd;
684     struct in_addr server;
685     int port;
686     Slirp *slirp;
687 };
688 
689 static int guestfwd_can_read(void *opaque)
690 {
691     struct GuestFwd *fwd = opaque;
692     return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);
693 }
694 
695 static void guestfwd_read(void *opaque, const uint8_t *buf, int size)
696 {
697     struct GuestFwd *fwd = opaque;
698     slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);
699 }
700 
701 static int slirp_guestfwd(SlirpState *s, const char *config_str,
702                           int legacy_format)
703 {
704     struct in_addr server = { .s_addr = 0 };
705     struct GuestFwd *fwd;
706     const char *p;
707     char buf[128];
708     char *end;
709     int port;
710 
711     p = config_str;
712     if (legacy_format) {
713         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
714             goto fail_syntax;
715         }
716     } else {
717         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
718             goto fail_syntax;
719         }
720         if (strcmp(buf, "tcp") && buf[0] != '\0') {
721             goto fail_syntax;
722         }
723         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
724             goto fail_syntax;
725         }
726         if (buf[0] != '\0' && !inet_aton(buf, &server)) {
727             goto fail_syntax;
728         }
729         if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
730             goto fail_syntax;
731         }
732     }
733     port = strtol(buf, &end, 10);
734     if (*end != '\0' || port < 1 || port > 65535) {
735         goto fail_syntax;
736     }
737 
738     snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port);
739 
740     if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) {
741         if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) {
742             error_report("conflicting/invalid host:port in guest forwarding "
743                          "rule '%s'", config_str);
744             return -1;
745         }
746     } else {
747         fwd = g_new(struct GuestFwd, 1);
748         fwd->hd = qemu_chr_new(buf, p, NULL);
749         if (!fwd->hd) {
750             error_report("could not open guest forwarding device '%s'", buf);
751             g_free(fwd);
752             return -1;
753         }
754 
755         if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) {
756             error_report("conflicting/invalid host:port in guest forwarding "
757                          "rule '%s'", config_str);
758             g_free(fwd);
759             return -1;
760         }
761         fwd->server = server;
762         fwd->port = port;
763         fwd->slirp = s->slirp;
764 
765         qemu_chr_fe_claim_no_fail(fwd->hd);
766         qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read,
767                               NULL, fwd);
768     }
769     return 0;
770 
771  fail_syntax:
772     error_report("invalid guest forwarding rule '%s'", config_str);
773     return -1;
774 }
775 
776 void hmp_info_usernet(Monitor *mon, const QDict *qdict)
777 {
778     SlirpState *s;
779 
780     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
781         int id;
782         bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;
783         monitor_printf(mon, "VLAN %d (%s):\n",
784                        got_vlan_id ? id : -1,
785                        s->nc.name);
786         slirp_connection_info(s->slirp, mon);
787     }
788 }
789 
790 static void
791 net_init_slirp_configs(const StringList *fwd, int flags)
792 {
793     while (fwd) {
794         struct slirp_config_str *config;
795 
796         config = g_malloc0(sizeof(*config));
797         pstrcpy(config->str, sizeof(config->str), fwd->value->str);
798         config->flags = flags;
799         config->next = slirp_configs;
800         slirp_configs = config;
801 
802         fwd = fwd->next;
803     }
804 }
805 
806 static const char **slirp_dnssearch(const StringList *dnsname)
807 {
808     const StringList *c = dnsname;
809     size_t i = 0, num_opts = 0;
810     const char **ret;
811 
812     while (c) {
813         num_opts++;
814         c = c->next;
815     }
816 
817     if (num_opts == 0) {
818         return NULL;
819     }
820 
821     ret = g_malloc((num_opts + 1) * sizeof(*ret));
822     c = dnsname;
823     while (c) {
824         ret[i++] = c->value->str;
825         c = c->next;
826     }
827     ret[i] = NULL;
828     return ret;
829 }
830 
831 int net_init_slirp(const Netdev *netdev, const char *name,
832                    NetClientState *peer, Error **errp)
833 {
834     /* FIXME error_setg(errp, ...) on failure */
835     struct slirp_config_str *config;
836     char *vnet;
837     int ret;
838     const NetdevUserOptions *user;
839     const char **dnssearch;
840     bool ipv4 = true, ipv6 = true;
841 
842     assert(netdev->type == NET_CLIENT_DRIVER_USER);
843     user = &netdev->u.user;
844 
845     if ((user->has_ipv6 && user->ipv6 && !user->has_ipv4) ||
846         (user->has_ipv4 && !user->ipv4)) {
847         ipv4 = 0;
848     }
849     if ((user->has_ipv4 && user->ipv4 && !user->has_ipv6) ||
850         (user->has_ipv6 && !user->ipv6)) {
851         ipv6 = 0;
852     }
853 
854     vnet = user->has_net ? g_strdup(user->net) :
855            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
856            NULL;
857 
858     dnssearch = slirp_dnssearch(user->dnssearch);
859 
860     /* all optional fields are initialized to "all bits zero" */
861 
862     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
863     net_init_slirp_configs(user->guestfwd, 0);
864 
865     ret = net_slirp_init(peer, "user", name, user->q_restrict,
866                          ipv4, vnet, user->host,
867                          ipv6, user->ipv6_prefix, user->ipv6_prefixlen,
868                          user->ipv6_host, user->hostname, user->tftp,
869                          user->bootfile, user->dhcpstart,
870                          user->dns, user->ipv6_dns, user->smb,
871                          user->smbserver, dnssearch);
872 
873     while (slirp_configs) {
874         config = slirp_configs;
875         slirp_configs = config->next;
876         g_free(config);
877     }
878 
879     g_free(vnet);
880     g_free(dnssearch);
881 
882     return ret;
883 }
884 
885 int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)
886 {
887     if (strcmp(opts_list->name, "net") != 0 ||
888         strncmp(optarg, "channel,", strlen("channel,")) != 0) {
889         return 0;
890     }
891 
892     error_report("The '-net channel' option is deprecated. "
893                  "Please use '-netdev user,guestfwd=...' instead.");
894 
895     /* handle legacy -net channel,port:chr */
896     optarg += strlen("channel,");
897 
898     if (QTAILQ_EMPTY(&slirp_stacks)) {
899         struct slirp_config_str *config;
900 
901         config = g_malloc(sizeof(*config));
902         pstrcpy(config->str, sizeof(config->str), optarg);
903         config->flags = SLIRP_CFG_LEGACY;
904         config->next = slirp_configs;
905         slirp_configs = config;
906         *ret = 0;
907     } else {
908         *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);
909     }
910 
911     return 1;
912 }
913 
914