net/slirp.c

   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 "net/slirp.h"
  25
  26 #include "config-host.h"
  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/sockets.h"
  37 #include "slirp/libslirp.h"
  38 #include "sysemu/char.h"
  39
  40 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
  41 {
  42     const char *p, *p1;
  43     int len;
  44     p = *pp;
  45     p1 = strchr(p, sep);
  46     if (!p1)
  47         return -1;
  48     len = p1 - p;
  49     p1++;
  50     if (buf_size > 0) {
  51         if (len > buf_size - 1)
  52             len = buf_size - 1;
  53         memcpy(buf, p, len);
  54         buf[len] = '\0';
  55     }
  56     *pp = p1;
  57     return 0;
  58 }
  59
  60 /* slirp network adapter */
  61
  62 #define SLIRP_CFG_HOSTFWD 1
  63 #define SLIRP_CFG_LEGACY  2
  64
  65 struct slirp_config_str {
  66     struct slirp_config_str *next;
  67     int flags;
  68     char str[1024];
  69     int legacy_format;
  70 };
  71
  72 typedef struct SlirpState {
  73     NetClientState nc;
  74     QTAILQ_ENTRY(SlirpState) entry;
  75     Slirp *slirp;
  76 #ifndef _WIN32
  77     char smb_dir[128];
  78 #endif
  79 } SlirpState;
  80
  81 static struct slirp_config_str *slirp_configs;
  82 const char *legacy_tftp_prefix;
  83 const char *legacy_bootp_filename;
  84 static QTAILQ_HEAD(slirp_stacks, SlirpState) slirp_stacks =
  85     QTAILQ_HEAD_INITIALIZER(slirp_stacks);
  86
  87 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
  88                          int legacy_format);
  89 static int slirp_guestfwd(SlirpState *s, const char *config_str,
  90                           int legacy_format);
  91
  92 #ifndef _WIN32
  93 static const char *legacy_smb_export;
  94
  95 static int slirp_smb(SlirpState *s, const char *exported_dir,
  96                      struct in_addr vserver_addr);
  97 static void slirp_smb_cleanup(SlirpState *s);
  98 #else
  99 static inline void slirp_smb_cleanup(SlirpState *s) { }
 100 #endif
 101
 102 void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)
 103 {
 104     SlirpState *s = opaque;
 105
 106     qemu_send_packet(&s->nc, pkt, pkt_len);
 107 }
 108
 109 static ssize_t net_slirp_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 110 {
 111     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
 112
 113     slirp_input(s->slirp, buf, size);
 114
 115     return size;
 116 }
 117
 118 static void net_slirp_cleanup(NetClientState *nc)
 119 {
 120     SlirpState *s = DO_UPCAST(SlirpState, nc, nc);
 121
 122     slirp_cleanup(s->slirp);
 123     slirp_smb_cleanup(s);
 124     QTAILQ_REMOVE(&slirp_stacks, s, entry);
 125 }
 126
 127 static NetClientInfo net_slirp_info = {
 128     .type = NET_CLIENT_OPTIONS_KIND_USER,
 129     .size = sizeof(SlirpState),
 130     .receive = net_slirp_receive,
 131     .cleanup = net_slirp_cleanup,
 132 };
 133
 134 static int net_slirp_init(NetClientState *peer, const char *model,
 135                           const char *name, int restricted,
 136                           const char *vnetwork, const char *vhost,
 137                           const char *vhostname, const char *tftp_export,
 138                           const char *bootfile, const char *vdhcp_start,
 139                           const char *vnameserver, const char *smb_export,
 140                           const char *vsmbserver, const char **dnssearch)
 141 {
 142     /* default settings according to historic slirp */
 143     struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */
 144     struct in_addr mask = { .s_addr = htonl(0xffffff00) }; /* 255.255.255.0 */
 145     struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
 146     struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
 147     struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
 148 #ifndef _WIN32
 149     struct in_addr smbsrv = { .s_addr = 0 };
 150 #endif
 151     NetClientState *nc;
 152     SlirpState *s;
 153     char buf[20];
 154     uint32_t addr;
 155     int shift;
 156     char *end;
 157     struct slirp_config_str *config;
 158
 159     if (!tftp_export) {
 160         tftp_export = legacy_tftp_prefix;
 161     }
 162     if (!bootfile) {
 163         bootfile = legacy_bootp_filename;
 164     }
 165
 166     if (vnetwork) {
 167         if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
 168             if (!inet_aton(vnetwork, &net)) {
 169                 return -1;
 170             }
 171             addr = ntohl(net.s_addr);
 172             if (!(addr & 0x80000000)) {
 173                 mask.s_addr = htonl(0xff000000); /* class A */
 174             } else if ((addr & 0xfff00000) == 0xac100000) {
 175                 mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
 176             } else if ((addr & 0xc0000000) == 0x80000000) {
 177                 mask.s_addr = htonl(0xffff0000); /* class B */
 178             } else if ((addr & 0xffff0000) == 0xc0a80000) {
 179                 mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
 180             } else if ((addr & 0xffff0000) == 0xc6120000) {
 181                 mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
 182             } else if ((addr & 0xe0000000) == 0xe0000000) {
 183                 mask.s_addr = htonl(0xffffff00); /* class C */
 184             } else {
 185                 mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
 186             }
 187         } else {
 188             if (!inet_aton(buf, &net)) {
 189                 return -1;
 190             }
 191             shift = strtol(vnetwork, &end, 10);
 192             if (*end != '\0') {
 193                 if (!inet_aton(vnetwork, &mask)) {
 194                     return -1;
 195                 }
 196             } else if (shift < 4 || shift > 32) {
 197                 return -1;
 198             } else {
 199                 mask.s_addr = htonl(0xffffffff << (32 - shift));
 200             }
 201         }
 202         net.s_addr &= mask.s_addr;
 203         host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
 204         dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
 205         dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
 206     }
 207
 208     if (vhost && !inet_aton(vhost, &host)) {
 209         return -1;
 210     }
 211     if ((host.s_addr & mask.s_addr) != net.s_addr) {
 212         return -1;
 213     }
 214
 215     if (vnameserver && !inet_aton(vnameserver, &dns)) {
 216         return -1;
 217     }
 218     if ((dns.s_addr & mask.s_addr) != net.s_addr ||
 219         dns.s_addr == host.s_addr) {
 220         return -1;
 221     }
 222
 223     if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
 224         return -1;
 225     }
 226     if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
 227         dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
 228         return -1;
 229     }
 230
 231 #ifndef _WIN32
 232     if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
 233         return -1;
 234     }
 235 #endif
 236
 237     nc = qemu_new_net_client(&net_slirp_info, peer, model, name);
 238
 239     snprintf(nc->info_str, sizeof(nc->info_str),
 240              "net=%s,restrict=%s", inet_ntoa(net),
 241              restricted ? "on" : "off");
 242
 243     s = DO_UPCAST(SlirpState, nc, nc);
 244
 245     s->slirp = slirp_init(restricted, net, mask, host, vhostname,
 246                           tftp_export, bootfile, dhcp, dns, dnssearch, s);
 247     QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);
 248
 249     for (config = slirp_configs; config; config = config->next) {
 250         if (config->flags & SLIRP_CFG_HOSTFWD) {
 251             if (slirp_hostfwd(s, config->str,
 252                               config->flags & SLIRP_CFG_LEGACY) < 0)
 253                 goto error;
 254         } else {
 255             if (slirp_guestfwd(s, config->str,
 256                                config->flags & SLIRP_CFG_LEGACY) < 0)
 257                 goto error;
 258         }
 259     }
 260 #ifndef _WIN32
 261     if (!smb_export) {
 262         smb_export = legacy_smb_export;
 263     }
 264     if (smb_export) {
 265         if (slirp_smb(s, smb_export, smbsrv) < 0)
 266             goto error;
 267     }
 268 #endif
 269
 270     return 0;
 271
 272 error:
 273     qemu_del_net_client(nc);
 274     return -1;
 275 }
 276
 277 static SlirpState *slirp_lookup(Monitor *mon, const char *vlan,
 278                                 const char *stack)
 279 {
 280
 281     if (vlan) {
 282         NetClientState *nc;
 283         nc = net_hub_find_client_by_name(strtol(vlan, NULL, 0), stack);
 284         if (!nc) {
 285             monitor_printf(mon, "unrecognized (vlan-id, stackname) pair\n");
 286             return NULL;
 287         }
 288         if (strcmp(nc->model, "user")) {
 289             monitor_printf(mon, "invalid device specified\n");
 290             return NULL;
 291         }
 292         return DO_UPCAST(SlirpState, nc, nc);
 293     } else {
 294         if (QTAILQ_EMPTY(&slirp_stacks)) {
 295             monitor_printf(mon, "user mode network stack not in use\n");
 296             return NULL;
 297         }
 298         return QTAILQ_FIRST(&slirp_stacks);
 299     }
 300 }
 301
 302 void net_slirp_hostfwd_remove(Monitor *mon, const QDict *qdict)
 303 {
 304     struct in_addr host_addr = { .s_addr = INADDR_ANY };
 305     int host_port;
 306     char buf[256];
 307     const char *src_str, *p;
 308     SlirpState *s;
 309     int is_udp = 0;
 310     int err;
 311     const char *arg1 = qdict_get_str(qdict, "arg1");
 312     const char *arg2 = qdict_get_try_str(qdict, "arg2");
 313     const char *arg3 = qdict_get_try_str(qdict, "arg3");
 314
 315     if (arg2) {
 316         s = slirp_lookup(mon, arg1, arg2);
 317         src_str = arg3;
 318     } else {
 319         s = slirp_lookup(mon, NULL, NULL);
 320         src_str = arg1;
 321     }
 322     if (!s) {
 323         return;
 324     }
 325
 326     p = src_str;
 327     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 328         goto fail_syntax;
 329     }
 330
 331     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
 332         is_udp = 0;
 333     } else if (!strcmp(buf, "udp")) {
 334         is_udp = 1;
 335     } else {
 336         goto fail_syntax;
 337     }
 338
 339     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 340         goto fail_syntax;
 341     }
 342     if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
 343         goto fail_syntax;
 344     }
 345
 346     host_port = atoi(p);
 347
 348     err = slirp_remove_hostfwd(s->slirp, is_udp, host_addr, host_port);
 349
 350     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
 351                    err ? "not found" : "removed");
 352     return;
 353
 354  fail_syntax:
 355     monitor_printf(mon, "invalid format\n");
 356 }
 357
 358 static int slirp_hostfwd(SlirpState *s, const char *redir_str,
 359                          int legacy_format)
 360 {
 361     struct in_addr host_addr = { .s_addr = INADDR_ANY };
 362     struct in_addr guest_addr = { .s_addr = 0 };
 363     int host_port, guest_port;
 364     const char *p;
 365     char buf[256];
 366     int is_udp;
 367     char *end;
 368
 369     p = redir_str;
 370     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 371         goto fail_syntax;
 372     }
 373     if (!strcmp(buf, "tcp") || buf[0] == '\0') {
 374         is_udp = 0;
 375     } else if (!strcmp(buf, "udp")) {
 376         is_udp = 1;
 377     } else {
 378         goto fail_syntax;
 379     }
 380
 381     if (!legacy_format) {
 382         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 383             goto fail_syntax;
 384         }
 385         if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {
 386             goto fail_syntax;
 387         }
 388     }
 389
 390     if (get_str_sep(buf, sizeof(buf), &p, legacy_format ? ':' : '-') < 0) {
 391         goto fail_syntax;
 392     }
 393     host_port = strtol(buf, &end, 0);
 394     if (*end != '\0' || host_port < 1 || host_port > 65535) {
 395         goto fail_syntax;
 396     }
 397
 398     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 399         goto fail_syntax;
 400     }
 401     if (buf[0] != '\0' && !inet_aton(buf, &guest_addr)) {
 402         goto fail_syntax;
 403     }
 404
 405     guest_port = strtol(p, &end, 0);
 406     if (*end != '\0' || guest_port < 1 || guest_port > 65535) {
 407         goto fail_syntax;
 408     }
 409
 410     if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,
 411                           guest_port) < 0) {
 412         error_report("could not set up host forwarding rule '%s'",
 413                      redir_str);
 414         return -1;
 415     }
 416     return 0;
 417
 418  fail_syntax:
 419     error_report("invalid host forwarding rule '%s'", redir_str);
 420     return -1;
 421 }
 422
 423 void net_slirp_hostfwd_add(Monitor *mon, const QDict *qdict)
 424 {
 425     const char *redir_str;
 426     SlirpState *s;
 427     const char *arg1 = qdict_get_str(qdict, "arg1");
 428     const char *arg2 = qdict_get_try_str(qdict, "arg2");
 429     const char *arg3 = qdict_get_try_str(qdict, "arg3");
 430
 431     if (arg2) {
 432         s = slirp_lookup(mon, arg1, arg2);
 433         redir_str = arg3;
 434     } else {
 435         s = slirp_lookup(mon, NULL, NULL);
 436         redir_str = arg1;
 437     }
 438     if (s) {
 439         slirp_hostfwd(s, redir_str, 0);
 440     }
 441
 442 }
 443
 444 int net_slirp_redir(const char *redir_str)
 445 {
 446     struct slirp_config_str *config;
 447
 448     if (QTAILQ_EMPTY(&slirp_stacks)) {
 449         config = g_malloc(sizeof(*config));
 450         pstrcpy(config->str, sizeof(config->str), redir_str);
 451         config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;
 452         config->next = slirp_configs;
 453         slirp_configs = config;
 454         return 0;
 455     }
 456
 457     return slirp_hostfwd(QTAILQ_FIRST(&slirp_stacks), redir_str, 1);
 458 }
 459
 460 #ifndef _WIN32
 461
 462 /* automatic user mode samba server configuration */
 463 static void slirp_smb_cleanup(SlirpState *s)
 464 {
 465     char cmd[128];
 466     int ret;
 467
 468     if (s->smb_dir[0] != '\0') {
 469         snprintf(cmd, sizeof(cmd), "rm -rf %s", s->smb_dir);
 470         ret = system(cmd);
 471         if (ret == -1 || !WIFEXITED(ret)) {
 472             error_report("'%s' failed.", cmd);
 473         } else if (WEXITSTATUS(ret)) {
 474             error_report("'%s' failed. Error code: %d",
 475                          cmd, WEXITSTATUS(ret));
 476         }
 477         s->smb_dir[0] = '\0';
 478     }
 479 }
 480
 481 static int slirp_smb(SlirpState* s, const char *exported_dir,
 482                      struct in_addr vserver_addr)
 483 {
 484     static int instance;
 485     char smb_conf[128];
 486     char smb_cmdline[128];
 487     struct passwd *passwd;
 488     FILE *f;
 489
 490     passwd = getpwuid(geteuid());
 491     if (!passwd) {
 492         error_report("failed to retrieve user name");
 493         return -1;
 494     }
 495
 496     if (access(CONFIG_SMBD_COMMAND, F_OK)) {
 497         error_report("could not find '%s', please install it",
 498                      CONFIG_SMBD_COMMAND);
 499         return -1;
 500     }
 501
 502     if (access(exported_dir, R_OK | X_OK)) {
 503         error_report("error accessing shared directory '%s': %s",
 504                      exported_dir, strerror(errno));
 505         return -1;
 506     }
 507
 508     snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.%ld-%d",
 509              (long)getpid(), instance++);
 510     if (mkdir(s->smb_dir, 0700) < 0) {
 511         error_report("could not create samba server dir '%s'", s->smb_dir);
 512         return -1;
 513     }
 514     snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");
 515
 516     f = fopen(smb_conf, "w");
 517     if (!f) {
 518         slirp_smb_cleanup(s);
 519         error_report("could not create samba server configuration file '%s'",
 520                      smb_conf);
 521         return -1;
 522     }
 523     fprintf(f,
 524             "[global]\n"
 525             "private dir=%s\n"
 526             "socket address=127.0.0.1\n"
 527             "pid directory=%s\n"
 528             "lock directory=%s\n"
 529             "state directory=%s\n"
 530             "ncalrpc dir=%s/ncalrpc\n"
 531             "log file=%s/log.smbd\n"
 532             "smb passwd file=%s/smbpasswd\n"
 533             "security = user\n"
 534             "map to guest = Bad User\n"
 535             "[qemu]\n"
 536             "path=%s\n"
 537             "read only=no\n"
 538             "guest ok=yes\n"
 539             "force user=%s\n",
 540             s->smb_dir,
 541             s->smb_dir,
 542             s->smb_dir,
 543             s->smb_dir,
 544             s->smb_dir,
 545             s->smb_dir,
 546             s->smb_dir,
 547             exported_dir,
 548             passwd->pw_name
 549             );
 550     fclose(f);
 551
 552     snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -s %s",
 553              CONFIG_SMBD_COMMAND, smb_conf);
 554
 555     if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0 ||
 556         slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 445) < 0) {
 557         slirp_smb_cleanup(s);
 558         error_report("conflicting/invalid smbserver address");
 559         return -1;
 560     }
 561     return 0;
 562 }
 563
 564 /* automatic user mode samba server configuration (legacy interface) */
 565 int net_slirp_smb(const char *exported_dir)
 566 {
 567     struct in_addr vserver_addr = { .s_addr = 0 };
 568
 569     if (legacy_smb_export) {
 570         fprintf(stderr, "-smb given twice\n");
 571         return -1;
 572     }
 573     legacy_smb_export = exported_dir;
 574     if (!QTAILQ_EMPTY(&slirp_stacks)) {
 575         return slirp_smb(QTAILQ_FIRST(&slirp_stacks), exported_dir,
 576                          vserver_addr);
 577     }
 578     return 0;
 579 }
 580
 581 #endif /* !defined(_WIN32) */
 582
 583 struct GuestFwd {
 584     CharDriverState *hd;
 585     struct in_addr server;
 586     int port;
 587     Slirp *slirp;
 588 };
 589
 590 static int guestfwd_can_read(void *opaque)
 591 {
 592     struct GuestFwd *fwd = opaque;
 593     return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);
 594 }
 595
 596 static void guestfwd_read(void *opaque, const uint8_t *buf, int size)
 597 {
 598     struct GuestFwd *fwd = opaque;
 599     slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);
 600 }
 601
 602 static int slirp_guestfwd(SlirpState *s, const char *config_str,
 603                           int legacy_format)
 604 {
 605     struct in_addr server = { .s_addr = 0 };
 606     struct GuestFwd *fwd;
 607     const char *p;
 608     char buf[128];
 609     char *end;
 610     int port;
 611
 612     p = config_str;
 613     if (legacy_format) {
 614         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 615             goto fail_syntax;
 616         }
 617     } else {
 618         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 619             goto fail_syntax;
 620         }
 621         if (strcmp(buf, "tcp") && buf[0] != '\0') {
 622             goto fail_syntax;
 623         }
 624         if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
 625             goto fail_syntax;
 626         }
 627         if (buf[0] != '\0' && !inet_aton(buf, &server)) {
 628             goto fail_syntax;
 629         }
 630         if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
 631             goto fail_syntax;
 632         }
 633     }
 634     port = strtol(buf, &end, 10);
 635     if (*end != '\0' || port < 1 || port > 65535) {
 636         goto fail_syntax;
 637     }
 638
 639     fwd = g_malloc(sizeof(struct GuestFwd));
 640     snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port);
 641
 642     if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) {
 643         if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) {
 644             error_report("conflicting/invalid host:port in guest forwarding "
 645                          "rule '%s'", config_str);
 646             g_free(fwd);
 647             return -1;
 648         }
 649     } else {
 650         fwd->hd = qemu_chr_new(buf, p, NULL);
 651         if (!fwd->hd) {
 652             error_report("could not open guest forwarding device '%s'", buf);
 653             g_free(fwd);
 654             return -1;
 655         }
 656
 657         if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) {
 658             error_report("conflicting/invalid host:port in guest forwarding "
 659                          "rule '%s'", config_str);
 660             g_free(fwd);
 661             return -1;
 662         }
 663         fwd->server = server;
 664         fwd->port = port;
 665         fwd->slirp = s->slirp;
 666
 667         qemu_chr_fe_claim_no_fail(fwd->hd);
 668         qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read,
 669                               NULL, fwd);
 670     }
 671     return 0;
 672
 673  fail_syntax:
 674     error_report("invalid guest forwarding rule '%s'", config_str);
 675     return -1;
 676 }
 677
 678 void do_info_usernet(Monitor *mon, const QDict *qdict)
 679 {
 680     SlirpState *s;
 681
 682     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
 683         int id;
 684         bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;
 685         monitor_printf(mon, "VLAN %d (%s):\n",
 686                        got_vlan_id ? id : -1,
 687                        s->nc.name);
 688         slirp_connection_info(s->slirp, mon);
 689     }
 690 }
 691
 692 static void
 693 net_init_slirp_configs(const StringList *fwd, int flags)
 694 {
 695     while (fwd) {
 696         struct slirp_config_str *config;
 697
 698         config = g_malloc0(sizeof(*config));
 699         pstrcpy(config->str, sizeof(config->str), fwd->value->str);
 700         config->flags = flags;
 701         config->next = slirp_configs;
 702         slirp_configs = config;
 703
 704         fwd = fwd->next;
 705     }
 706 }
 707
 708 static const char **slirp_dnssearch(const StringList *dnsname)
 709 {
 710     const StringList *c = dnsname;
 711     size_t i = 0, num_opts = 0;
 712     const char **ret;
 713
 714     while (c) {
 715         num_opts++;
 716         c = c->next;
 717     }
 718
 719     if (num_opts == 0) {
 720         return NULL;
 721     }
 722
 723     ret = g_malloc((num_opts + 1) * sizeof(*ret));
 724     c = dnsname;
 725     while (c) {
 726         ret[i++] = c->value->str;
 727         c = c->next;
 728     }
 729     ret[i] = NULL;
 730     return ret;
 731 }
 732
 733 int net_init_slirp(const NetClientOptions *opts, const char *name,
 734                    NetClientState *peer)
 735 {
 736     struct slirp_config_str *config;
 737     char *vnet;
 738     int ret;
 739     const NetdevUserOptions *user;
 740     const char **dnssearch;
 741
 742     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_USER);
 743     user = opts->user;
 744
 745     vnet = user->has_net ? g_strdup(user->net) :
 746            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
 747            NULL;
 748
 749     dnssearch = slirp_dnssearch(user->dnssearch);
 750
 751     /* all optional fields are initialized to "all bits zero" */
 752
 753     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
 754     net_init_slirp_configs(user->guestfwd, 0);
 755
 756     ret = net_slirp_init(peer, "user", name, user->q_restrict, vnet,
 757                          user->host, user->hostname, user->tftp,
 758                          user->bootfile, user->dhcpstart, user->dns, user->smb,
 759                          user->smbserver, dnssearch);
 760
 761     while (slirp_configs) {
 762         config = slirp_configs;
 763         slirp_configs = config->next;
 764         g_free(config);
 765     }
 766
 767     g_free(vnet);
 768     g_free(dnssearch);
 769
 770     return ret;
 771 }
 772
 773 int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)
 774 {
 775     if (strcmp(opts_list->name, "net") != 0 ||
 776         strncmp(optarg, "channel,", strlen("channel,")) != 0) {
 777         return 0;
 778     }
 779
 780     /* handle legacy -net channel,port:chr */
 781     optarg += strlen("channel,");
 782
 783     if (QTAILQ_EMPTY(&slirp_stacks)) {
 784         struct slirp_config_str *config;
 785
 786         config = g_malloc(sizeof(*config));
 787         pstrcpy(config->str, sizeof(config->str), optarg);
 788         config->flags = SLIRP_CFG_LEGACY;
 789         config->next = slirp_configs;
 790         slirp_configs = config;
 791         *ret = 0;
 792     } else {
 793         *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);
 794     }
 795
 796     return 1;
 797 }
 798