xref: /qemu/net/slirp.c (revision ef291226) 
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 #include "qapi/error.h"
44 
45 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
46 {
47     const char *p, *p1;
48     int len;
49     p = *pp;
50     p1 = strchr(p, sep);
51     if (!p1)
52         return -1;
53     len = p1 - p;
54     p1++;
55     if (buf_size > 0) {
56         if (len > buf_size - 1)
57             len = buf_size - 1;
58         memcpy(buf, p, len);
59         buf[len] = '\0';
60     }
61     *pp = p1;
62     return 0;
63 }
64 
65 /* slirp network adapter */
66 
67 #define SLIRP_CFG_HOSTFWD 1
68 #define SLIRP_CFG_LEGACY  2
69 
70 struct slirp_config_str {
71     struct slirp_config_str *next;
72     int flags;
73     char str[1024];
74     int legacy_format;
75 };
76 
77 typedef struct SlirpState {
78     NetClientState nc;
79     QTAILQ_ENTRY(SlirpState) entry;
80     Slirp *slirp;
81     Notifier exit_notifier;
82 #ifndef _WIN32
83     char smb_dir[128];
84 #endif
85 } SlirpState;
86 
87 static struct slirp_config_str *slirp_configs;
88 const char *legacy_tftp_prefix;
89 const char *legacy_bootp_filename;
90 static QTAILQ_HEAD(slirp_stacks, SlirpState) slirp_stacks =
91     QTAILQ_HEAD_INITIALIZER(slirp_stacks);
92 
93 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
94                          int legacy_format);
95 static int slirp_guestfwd(SlirpState *s, const char *config_str,
96                           int legacy_format);
97 
98 #ifndef _WIN32
99 static const char *legacy_smb_export;
100 
101 static int slirp_smb(SlirpState *s, const char *exported_dir,
102                      struct in_addr vserver_addr);
103 static void slirp_smb_cleanup(SlirpState *s);
104 #else
105 static inline void slirp_smb_cleanup(SlirpState *s) { }
106 #endif
107 
108 void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)
109 {
110     SlirpState *s = opaque;
111 
112     qemu_send_packet(&s->nc, pkt, pkt_len);
113 }
114 
115 static ssize_t net_slirp_receive(NetClientState *nc, const uint8_t *buf, size_t size)
116 {
117     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
118 
119     slirp_input(s->slirp, buf, size);
120 
121     return size;
122 }
123 
124 static void slirp_smb_exit(Notifier *n, void *data)
125 {
126     SlirpState *s = container_of(n, SlirpState, exit_notifier);
127     slirp_smb_cleanup(s);
128 }
129 
130 static void net_slirp_cleanup(NetClientState *nc)
131 {
132     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
133 
134     slirp_cleanup(s->slirp);
135     if (s->exit_notifier.notify) {
136         qemu_remove_exit_notifier(&s->exit_notifier);
137     }
138     slirp_smb_cleanup(s);
139     QTAILQ_REMOVE(&slirp_stacks, s, entry);
140 }
141 
142 static NetClientInfo net_slirp_info = {
143     .type = NET_CLIENT_DRIVER_USER,
144     .size = sizeof(SlirpState),
145     .receive = net_slirp_receive,
146     .cleanup = net_slirp_cleanup,
147 };
148 
149 static int net_slirp_init(NetClientState *peer, const char *model,
150                           const char *name, int restricted,
151                           bool ipv4, const char *vnetwork, const char *vhost,
152                           bool ipv6, const char *vprefix6, int vprefix6_len,
153                           const char *vhost6,
154                           const char *vhostname, const char *tftp_export,
155                           const char *bootfile, const char *vdhcp_start,
156                           const char *vnameserver, const char *vnameserver6,
157                           const char *smb_export, const char *vsmbserver,
158                           const char **dnssearch)
159 {
160     /* default settings according to historic slirp */
161     struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */
162     struct in_addr mask = { .s_addr = htonl(0xffffff00) }; /* 255.255.255.0 */
163     struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
164     struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
165     struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
166     struct in6_addr ip6_prefix;
167     struct in6_addr ip6_host;
168     struct in6_addr ip6_dns;
169 #ifndef _WIN32
170     struct in_addr smbsrv = { .s_addr = 0 };
171 #endif
172     NetClientState *nc;
173     SlirpState *s;
174     char buf[20];
175     uint32_t addr;
176     int shift;
177     char *end;
178     struct slirp_config_str *config;
179 
180     if (!ipv4 && (vnetwork || vhost || vnameserver)) {
181         return -1;
182     }
183 
184     if (!ipv6 && (vprefix6 || vhost6 || vnameserver6)) {
185         return -1;
186     }
187 
188     if (!ipv4 && !ipv6) {
189         /* It doesn't make sense to disable both */
190         return -1;
191     }
192 
193     if (!tftp_export) {
194         tftp_export = legacy_tftp_prefix;
195     }
196     if (!bootfile) {
197         bootfile = legacy_bootp_filename;
198     }
199 
200     if (vnetwork) {
201         if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
202             if (!inet_aton(vnetwork, &net)) {
203                 return -1;
204             }
205             addr = ntohl(net.s_addr);
206             if (!(addr & 0x80000000)) {
207                 mask.s_addr = htonl(0xff000000); /* class A */
208             } else if ((addr & 0xfff00000) == 0xac100000) {
209                 mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
210             } else if ((addr & 0xc0000000) == 0x80000000) {
211                 mask.s_addr = htonl(0xffff0000); /* class B */
212             } else if ((addr & 0xffff0000) == 0xc0a80000) {
213                 mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
214             } else if ((addr & 0xffff0000) == 0xc6120000) {
215                 mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
216             } else if ((addr & 0xe0000000) == 0xe0000000) {
217                 mask.s_addr = htonl(0xffffff00); /* class C */
218             } else {
219                 mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
220             }
221         } else {
222             if (!inet_aton(buf, &net)) {
223                 return -1;
224             }
225             shift = strtol(vnetwork, &end, 10);
226             if (*end != '\0') {
227                 if (!inet_aton(vnetwork, &mask)) {
228                     return -1;
229                 }
230             } else if (shift < 4 || shift > 32) {
231                 return -1;
232             } else {
233                 mask.s_addr = htonl(0xffffffff << (32 - shift));
234             }
235         }
236         net.s_addr &= mask.s_addr;
237         host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
238         dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
239         dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
240     }
241 
242     if (vhost && !inet_aton(vhost, &host)) {
243         return -1;
244     }
245     if ((host.s_addr & mask.s_addr) != net.s_addr) {
246         return -1;
247     }
248 
249     if (vnameserver && !inet_aton(vnameserver, &dns)) {
250         return -1;
251     }
252     if ((dns.s_addr & mask.s_addr) != net.s_addr ||
253         dns.s_addr == host.s_addr) {
254         return -1;
255     }
256 
257     if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
258         return -1;
259     }
260     if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
261         dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
262         return -1;
263     }
264 
265 #ifndef _WIN32
266     if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
267         return -1;
268     }
269 #endif
270 
271 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
272     /* No inet_pton helper before Vista... */
273     if (vprefix6) {
274         /* Unsupported */
275         return -1;
276     }
277     memset(&ip6_prefix, 0, sizeof(ip6_prefix));
278     ip6_prefix.s6_addr[0] = 0xfe;
279     ip6_prefix.s6_addr[1] = 0xc0;
280 #else
281     if (!vprefix6) {
282         vprefix6 = "fec0::";
283     }
284     if (!inet_pton(AF_INET6, vprefix6, &ip6_prefix)) {
285         return -1;
286     }
287 #endif
288 
289     if (!vprefix6_len) {
290         vprefix6_len = 64;
291     }
292     if (vprefix6_len < 0 || vprefix6_len > 126) {
293         return -1;
294     }
295 
296     if (vhost6) {
297 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
298         return -1;
299 #else
300         if (!inet_pton(AF_INET6, vhost6, &ip6_host)) {
301             return -1;
302         }
303         if (!in6_equal_net(&ip6_prefix, &ip6_host, vprefix6_len)) {
304             return -1;
305         }
306 #endif
307     } else {
308         ip6_host = ip6_prefix;
309         ip6_host.s6_addr[15] |= 2;
310     }
311 
312     if (vnameserver6) {
313 #if defined(_WIN32) && (_WIN32_WINNT < 0x0600)
314         return -1;
315 #else
316         if (!inet_pton(AF_INET6, vnameserver6, &ip6_dns)) {
317             return -1;
318         }
319         if (!in6_equal_net(&ip6_prefix, &ip6_dns, vprefix6_len)) {
320             return -1;
321         }
322 #endif
323     } else {
324         ip6_dns = ip6_prefix;
325         ip6_dns.s6_addr[15] |= 3;
326     }
327 
328 
329     nc = qemu_new_net_client(&net_slirp_info, peer, model, name);
330 
331     snprintf(nc->info_str, sizeof(nc->info_str),
332              "net=%s,restrict=%s", inet_ntoa(net),
333              restricted ? "on" : "off");
334 
335     s = DO_UPCAST(SlirpState, nc, nc);
336 
337     s->slirp = slirp_init(restricted, ipv4, net, mask, host,
338                           ipv6, ip6_prefix, vprefix6_len, ip6_host,
339                           vhostname, tftp_export, bootfile, dhcp,
340                           dns, ip6_dns, dnssearch, s);
341     QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);
342 
343     for (config = slirp_configs; config; config = config->next) {
344         if (config->flags & SLIRP_CFG_HOSTFWD) {
345             if (slirp_hostfwd(s, config->str,
346                               config->flags & SLIRP_CFG_LEGACY) < 0)
347                 goto error;
348         } else {
349             if (slirp_guestfwd(s, config->str,
350                                config->flags & SLIRP_CFG_LEGACY) < 0)
351                 goto error;
352         }
353     }
354 #ifndef _WIN32
355     if (!smb_export) {
356         smb_export = legacy_smb_export;
357     }
358     if (smb_export) {
359         if (slirp_smb(s, smb_export, smbsrv) < 0)
360             goto error;
361     }
362 #endif
363 
364     s->exit_notifier.notify = slirp_smb_exit;
365     qemu_add_exit_notifier(&s->exit_notifier);
366     return 0;
367 
368 error:
369     qemu_del_net_client(nc);
370     return -1;
371 }
372 
373 static SlirpState *slirp_lookup(Monitor *mon, const char *vlan,
374                                 const char *stack)
375 {
376 
377     if (vlan) {
378         NetClientState *nc;
379         nc = net_hub_find_client_by_name(strtol(vlan, NULL, 0), stack);
380         if (!nc) {
381             monitor_printf(mon, "unrecognized (vlan-id, stackname) pair\n");
382             return NULL;
383         }
384         if (strcmp(nc->model, "user")) {
385             monitor_printf(mon, "invalid device specified\n");
386             return NULL;
387         }
388         return DO_UPCAST(SlirpState, nc, nc);
389     } else {
390         if (QTAILQ_EMPTY(&slirp_stacks)) {
391             monitor_printf(mon, "user mode network stack not in use\n");
392             return NULL;
393         }
394         return QTAILQ_FIRST(&slirp_stacks);
395     }
396 }
397 
398 void hmp_hostfwd_remove(Monitor *mon, const QDict *qdict)
399 {
400     struct in_addr host_addr = { .s_addr = INADDR_ANY };
401     int host_port;
402     char buf[256];
403     const char *src_str, *p;
404     SlirpState *s;
405     int is_udp = 0;
406     int err;
407     const char *arg1 = qdict_get_str(qdict, "arg1");
408     const char *arg2 = qdict_get_try_str(qdict, "arg2");
409     const char *arg3 = qdict_get_try_str(qdict, "arg3");
410 
411     if (arg2) {
412         s = slirp_lookup(mon, arg1, arg2);
413         src_str = arg3;
414     } else {
415         s = slirp_lookup(mon, NULL, NULL);
416         src_str = arg1;
417     }
418     if (!s) {
419         return;
420     }
421 
422     p = src_str;
423     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
424         goto fail_syntax;
425     }
426 
427     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
428         is_udp = 0;
429     } else if (!strcmp(buf, "udp")) {
430         is_udp = 1;
431     } else {
432         goto fail_syntax;
433     }
434 
435     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
436         goto fail_syntax;
437     }
438     if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
439         goto fail_syntax;
440     }
441 
442     host_port = atoi(p);
443 
444     err = slirp_remove_hostfwd(s->slirp, is_udp, host_addr, host_port);
445 
446     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
447                    err ? "not found" : "removed");
448     return;
449 
450  fail_syntax:
451     monitor_printf(mon, "invalid format\n");
452 }
453 
454 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
455                          int legacy_format)
456 {
457     struct in_addr host_addr = { .s_addr = INADDR_ANY };
458     struct in_addr guest_addr = { .s_addr = 0 };
459     int host_port, guest_port;
460     const char *p;
461     char buf[256];
462     int is_udp;
463     char *end;
464 
465     p = redir_str;
466     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
467         goto fail_syntax;
468     }
469     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
470         is_udp = 0;
471     } else if (!strcmp(buf, "udp")) {
472         is_udp = 1;
473     } else {
474         goto fail_syntax;
475     }
476 
477     if (!legacy_format) {
478         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
479             goto fail_syntax;
480         }
481         if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
482             goto fail_syntax;
483         }
484     }
485 
486     if (get_str_sep(buf, sizeof(buf), &p, legacy_format ? ':' : '-') < 0) {
487         goto fail_syntax;
488     }
489     host_port = strtol(buf, &end, 0);
490     if (*end != '\0' || host_port < 1 || host_port > 65535) {
491         goto fail_syntax;
492     }
493 
494     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
495         goto fail_syntax;
496     }
497     if (buf[0] != '\0' && !inet_aton(buf, &guest_addr)) {
498         goto fail_syntax;
499     }
500 
501     guest_port = strtol(p, &end, 0);
502     if (*end != '\0' || guest_port < 1 || guest_port > 65535) {
503         goto fail_syntax;
504     }
505 
506     if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,
507                           guest_port) < 0) {
508         error_report("could not set up host forwarding rule '%s'",
509                      redir_str);
510         return -1;
511     }
512     return 0;
513 
514  fail_syntax:
515     error_report("invalid host forwarding rule '%s'", redir_str);
516     return -1;
517 }
518 
519 void hmp_hostfwd_add(Monitor *mon, const QDict *qdict)
520 {
521     const char *redir_str;
522     SlirpState *s;
523     const char *arg1 = qdict_get_str(qdict, "arg1");
524     const char *arg2 = qdict_get_try_str(qdict, "arg2");
525     const char *arg3 = qdict_get_try_str(qdict, "arg3");
526 
527     if (arg2) {
528         s = slirp_lookup(mon, arg1, arg2);
529         redir_str = arg3;
530     } else {
531         s = slirp_lookup(mon, NULL, NULL);
532         redir_str = arg1;
533     }
534     if (s) {
535         slirp_hostfwd(s, redir_str, 0);
536     }
537 
538 }
539 
540 int net_slirp_redir(const char *redir_str)
541 {
542     struct slirp_config_str *config;
543 
544     if (QTAILQ_EMPTY(&slirp_stacks)) {
545         config = g_malloc(sizeof(*config));
546         pstrcpy(config->str, sizeof(config->str), redir_str);
547         config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;
548         config->next = slirp_configs;
549         slirp_configs = config;
550         return 0;
551     }
552 
553     return slirp_hostfwd(QTAILQ_FIRST(&slirp_stacks), redir_str, 1);
554 }
555 
556 #ifndef _WIN32
557 
558 /* automatic user mode samba server configuration */
559 static void slirp_smb_cleanup(SlirpState *s)
560 {
561     char cmd[128];
562     int ret;
563 
564     if (s->smb_dir[0] != '\0') {
565         snprintf(cmd, sizeof(cmd), "rm -rf %s", s->smb_dir);
566         ret = system(cmd);
567         if (ret == -1 || !WIFEXITED(ret)) {
568             error_report("'%s' failed.", cmd);
569         } else if (WEXITSTATUS(ret)) {
570             error_report("'%s' failed. Error code: %d",
571                          cmd, WEXITSTATUS(ret));
572         }
573         s->smb_dir[0] = '\0';
574     }
575 }
576 
577 static int slirp_smb(SlirpState* s, const char *exported_dir,
578                      struct in_addr vserver_addr)
579 {
580     char smb_conf[128];
581     char smb_cmdline[128];
582     struct passwd *passwd;
583     FILE *f;
584 
585     passwd = getpwuid(geteuid());
586     if (!passwd) {
587         error_report("failed to retrieve user name");
588         return -1;
589     }
590 
591     if (access(CONFIG_SMBD_COMMAND, F_OK)) {
592         error_report("could not find '%s', please install it",
593                      CONFIG_SMBD_COMMAND);
594         return -1;
595     }
596 
597     if (access(exported_dir, R_OK | X_OK)) {
598         error_report("error accessing shared directory '%s': %s",
599                      exported_dir, strerror(errno));
600         return -1;
601     }
602 
603     snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.XXXXXX");
604     if (!mkdtemp(s->smb_dir)) {
605         error_report("could not create samba server dir '%s'", s->smb_dir);
606         s->smb_dir[0] = 0;
607         return -1;
608     }
609     snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");
610 
611     f = fopen(smb_conf, "w");
612     if (!f) {
613         slirp_smb_cleanup(s);
614         error_report("could not create samba server configuration file '%s'",
615                      smb_conf);
616         return -1;
617     }
618     fprintf(f,
619             "[global]\n"
620             "private dir=%s\n"
621             "interfaces=127.0.0.1\n"
622             "bind interfaces only=yes\n"
623             "pid directory=%s\n"
624             "lock directory=%s\n"
625             "state directory=%s\n"
626             "cache directory=%s\n"
627             "ncalrpc dir=%s/ncalrpc\n"
628             "log file=%s/log.smbd\n"
629             "smb passwd file=%s/smbpasswd\n"
630             "security = user\n"
631             "map to guest = Bad User\n"
632             "load printers = no\n"
633             "printing = bsd\n"
634             "disable spoolss = yes\n"
635             "usershare max shares = 0\n"
636             "[qemu]\n"
637             "path=%s\n"
638             "read only=no\n"
639             "guest ok=yes\n"
640             "force user=%s\n",
641             s->smb_dir,
642             s->smb_dir,
643             s->smb_dir,
644             s->smb_dir,
645             s->smb_dir,
646             s->smb_dir,
647             s->smb_dir,
648             s->smb_dir,
649             exported_dir,
650             passwd->pw_name
651             );
652     fclose(f);
653 
654     snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -l %s -s %s",
655              CONFIG_SMBD_COMMAND, s->smb_dir, smb_conf);
656 
657     if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0 ||
658         slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 445) < 0) {
659         slirp_smb_cleanup(s);
660         error_report("conflicting/invalid smbserver address");
661         return -1;
662     }
663     return 0;
664 }
665 
666 /* automatic user mode samba server configuration (legacy interface) */
667 int net_slirp_smb(const char *exported_dir)
668 {
669     struct in_addr vserver_addr = { .s_addr = 0 };
670 
671     if (legacy_smb_export) {
672         fprintf(stderr, "-smb given twice\n");
673         return -1;
674     }
675     legacy_smb_export = exported_dir;
676     if (!QTAILQ_EMPTY(&slirp_stacks)) {
677         return slirp_smb(QTAILQ_FIRST(&slirp_stacks), exported_dir,
678                          vserver_addr);
679     }
680     return 0;
681 }
682 
683 #endif /* !defined(_WIN32) */
684 
685 struct GuestFwd {
686     CharBackend hd;
687     struct in_addr server;
688     int port;
689     Slirp *slirp;
690 };
691 
692 static int guestfwd_can_read(void *opaque)
693 {
694     struct GuestFwd *fwd = opaque;
695     return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);
696 }
697 
698 static void guestfwd_read(void *opaque, const uint8_t *buf, int size)
699 {
700     struct GuestFwd *fwd = opaque;
701     slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);
702 }
703 
704 static int slirp_guestfwd(SlirpState *s, const char *config_str,
705                           int legacy_format)
706 {
707     struct in_addr server = { .s_addr = 0 };
708     struct GuestFwd *fwd;
709     const char *p;
710     char buf[128];
711     char *end;
712     int port;
713 
714     p = config_str;
715     if (legacy_format) {
716         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
717             goto fail_syntax;
718         }
719     } else {
720         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
721             goto fail_syntax;
722         }
723         if (strcmp(buf, "tcp") && buf[0] != '\0') {
724             goto fail_syntax;
725         }
726         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
727             goto fail_syntax;
728         }
729         if (buf[0] != '\0' && !inet_aton(buf, &server)) {
730             goto fail_syntax;
731         }
732         if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
733             goto fail_syntax;
734         }
735     }
736     port = strtol(buf, &end, 10);
737     if (*end != '\0' || port < 1 || port > 65535) {
738         goto fail_syntax;
739     }
740 
741     snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port);
742 
743     if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) {
744         if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) {
745             error_report("conflicting/invalid host:port in guest forwarding "
746                          "rule '%s'", config_str);
747             return -1;
748         }
749     } else {
750         Error *err = NULL;
751         Chardev *chr = qemu_chr_new(buf, p);
752 
753         if (!chr) {
754             error_report("could not open guest forwarding device '%s'", buf);
755             return -1;
756         }
757 
758         fwd = g_new(struct GuestFwd, 1);
759         qemu_chr_fe_init(&fwd->hd, chr, &err);
760         if (err) {
761             error_report_err(err);
762             g_free(fwd);
763             return -1;
764         }
765 
766         if (slirp_add_exec(s->slirp, 3, &fwd->hd, &server, port) < 0) {
767             error_report("conflicting/invalid host:port in guest forwarding "
768                          "rule '%s'", config_str);
769             g_free(fwd);
770             return -1;
771         }
772         fwd->server = server;
773         fwd->port = port;
774         fwd->slirp = s->slirp;
775 
776         qemu_chr_fe_set_handlers(&fwd->hd, guestfwd_can_read, guestfwd_read,
777                                  NULL, fwd, NULL, true);
778     }
779     return 0;
780 
781  fail_syntax:
782     error_report("invalid guest forwarding rule '%s'", config_str);
783     return -1;
784 }
785 
786 void hmp_info_usernet(Monitor *mon, const QDict *qdict)
787 {
788     SlirpState *s;
789 
790     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
791         int id;
792         bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;
793         monitor_printf(mon, "VLAN %d (%s):\n",
794                        got_vlan_id ? id : -1,
795                        s->nc.name);
796         slirp_connection_info(s->slirp, mon);
797     }
798 }
799 
800 static void
801 net_init_slirp_configs(const StringList *fwd, int flags)
802 {
803     while (fwd) {
804         struct slirp_config_str *config;
805 
806         config = g_malloc0(sizeof(*config));
807         pstrcpy(config->str, sizeof(config->str), fwd->value->str);
808         config->flags = flags;
809         config->next = slirp_configs;
810         slirp_configs = config;
811 
812         fwd = fwd->next;
813     }
814 }
815 
816 static const char **slirp_dnssearch(const StringList *dnsname)
817 {
818     const StringList *c = dnsname;
819     size_t i = 0, num_opts = 0;
820     const char **ret;
821 
822     while (c) {
823         num_opts++;
824         c = c->next;
825     }
826 
827     if (num_opts == 0) {
828         return NULL;
829     }
830 
831     ret = g_malloc((num_opts + 1) * sizeof(*ret));
832     c = dnsname;
833     while (c) {
834         ret[i++] = c->value->str;
835         c = c->next;
836     }
837     ret[i] = NULL;
838     return ret;
839 }
840 
841 int net_init_slirp(const Netdev *netdev, const char *name,
842                    NetClientState *peer, Error **errp)
843 {
844     /* FIXME error_setg(errp, ...) on failure */
845     struct slirp_config_str *config;
846     char *vnet;
847     int ret;
848     const NetdevUserOptions *user;
849     const char **dnssearch;
850     bool ipv4 = true, ipv6 = true;
851 
852     assert(netdev->type == NET_CLIENT_DRIVER_USER);
853     user = &netdev->u.user;
854 
855     if ((user->has_ipv6 && user->ipv6 && !user->has_ipv4) ||
856         (user->has_ipv4 && !user->ipv4)) {
857         ipv4 = 0;
858     }
859     if ((user->has_ipv4 && user->ipv4 && !user->has_ipv6) ||
860         (user->has_ipv6 && !user->ipv6)) {
861         ipv6 = 0;
862     }
863 
864     vnet = user->has_net ? g_strdup(user->net) :
865            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
866            NULL;
867 
868     dnssearch = slirp_dnssearch(user->dnssearch);
869 
870     /* all optional fields are initialized to "all bits zero" */
871 
872     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
873     net_init_slirp_configs(user->guestfwd, 0);
874 
875     ret = net_slirp_init(peer, "user", name, user->q_restrict,
876                          ipv4, vnet, user->host,
877                          ipv6, user->ipv6_prefix, user->ipv6_prefixlen,
878                          user->ipv6_host, user->hostname, user->tftp,
879                          user->bootfile, user->dhcpstart,
880                          user->dns, user->ipv6_dns, user->smb,
881                          user->smbserver, dnssearch);
882 
883     while (slirp_configs) {
884         config = slirp_configs;
885         slirp_configs = config->next;
886         g_free(config);
887     }
888 
889     g_free(vnet);
890     g_free(dnssearch);
891 
892     return ret;
893 }
894 
895 int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)
896 {
897     if (strcmp(opts_list->name, "net") != 0 ||
898         strncmp(optarg, "channel,", strlen("channel,")) != 0) {
899         return 0;
900     }
901 
902     error_report("The '-net channel' option is deprecated. "
903                  "Please use '-netdev user,guestfwd=...' instead.");
904 
905     /* handle legacy -net channel,port:chr */
906     optarg += strlen("channel,");
907 
908     if (QTAILQ_EMPTY(&slirp_stacks)) {
909         struct slirp_config_str *config;
910 
911         config = g_malloc(sizeof(*config));
912         pstrcpy(config->str, sizeof(config->str), optarg);
913         config->flags = SLIRP_CFG_LEGACY;
914         config->next = slirp_configs;
915         slirp_configs = config;
916         *ret = 0;
917     } else {
918         *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);
919     }
920 
921     return 1;
922 }
923 
924