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 "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         CharDriverState *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, qemu_chr_fe_get_driver(&fwd->hd),
 767                            &server, port) < 0) {
 768             error_report("conflicting/invalid host:port in guest forwarding "
 769                          "rule '%s'", config_str);
 770             g_free(fwd);
 771             return -1;
 772         }
 773         fwd->server = server;
 774         fwd->port = port;
 775         fwd->slirp = s->slirp;
 776
 777         qemu_chr_fe_set_handlers(&fwd->hd, guestfwd_can_read, guestfwd_read,
 778                                  NULL, fwd, NULL, true);
 779     }
 780     return 0;
 781
 782  fail_syntax:
 783     error_report("invalid guest forwarding rule '%s'", config_str);
 784     return -1;
 785 }
 786
 787 void hmp_info_usernet(Monitor *mon, const QDict *qdict)
 788 {
 789     SlirpState *s;
 790
 791     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
 792         int id;
 793         bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;
 794         monitor_printf(mon, "VLAN %d (%s):\n",
 795                        got_vlan_id ? id : -1,
 796                        s->nc.name);
 797         slirp_connection_info(s->slirp, mon);
 798     }
 799 }
 800
 801 static void
 802 net_init_slirp_configs(const StringList *fwd, int flags)
 803 {
 804     while (fwd) {
 805         struct slirp_config_str *config;
 806
 807         config = g_malloc0(sizeof(*config));
 808         pstrcpy(config->str, sizeof(config->str), fwd->value->str);
 809         config->flags = flags;
 810         config->next = slirp_configs;
 811         slirp_configs = config;
 812
 813         fwd = fwd->next;
 814     }
 815 }
 816
 817 static const char **slirp_dnssearch(const StringList *dnsname)
 818 {
 819     const StringList *c = dnsname;
 820     size_t i = 0, num_opts = 0;
 821     const char **ret;
 822
 823     while (c) {
 824         num_opts++;
 825         c = c->next;
 826     }
 827
 828     if (num_opts == 0) {
 829         return NULL;
 830     }
 831
 832     ret = g_malloc((num_opts + 1) * sizeof(*ret));
 833     c = dnsname;
 834     while (c) {
 835         ret[i++] = c->value->str;
 836         c = c->next;
 837     }
 838     ret[i] = NULL;
 839     return ret;
 840 }
 841
 842 int net_init_slirp(const Netdev *netdev, const char *name,
 843                    NetClientState *peer, Error **errp)
 844 {
 845     /* FIXME error_setg(errp, ...) on failure */
 846     struct slirp_config_str *config;
 847     char *vnet;
 848     int ret;
 849     const NetdevUserOptions *user;
 850     const char **dnssearch;
 851     bool ipv4 = true, ipv6 = true;
 852
 853     assert(netdev->type == NET_CLIENT_DRIVER_USER);
 854     user = &netdev->u.user;
 855
 856     if ((user->has_ipv6 && user->ipv6 && !user->has_ipv4) ||
 857         (user->has_ipv4 && !user->ipv4)) {
 858         ipv4 = 0;
 859     }
 860     if ((user->has_ipv4 && user->ipv4 && !user->has_ipv6) ||
 861         (user->has_ipv6 && !user->ipv6)) {
 862         ipv6 = 0;
 863     }
 864
 865     vnet = user->has_net ? g_strdup(user->net) :
 866            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
 867            NULL;
 868
 869     dnssearch = slirp_dnssearch(user->dnssearch);
 870
 871     /* all optional fields are initialized to "all bits zero" */
 872
 873     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
 874     net_init_slirp_configs(user->guestfwd, 0);
 875
 876     ret = net_slirp_init(peer, "user", name, user->q_restrict,
 877                          ipv4, vnet, user->host,
 878                          ipv6, user->ipv6_prefix, user->ipv6_prefixlen,
 879                          user->ipv6_host, user->hostname, user->tftp,
 880                          user->bootfile, user->dhcpstart,
 881                          user->dns, user->ipv6_dns, user->smb,
 882                          user->smbserver, dnssearch);
 883
 884     while (slirp_configs) {
 885         config = slirp_configs;
 886         slirp_configs = config->next;
 887         g_free(config);
 888     }
 889
 890     g_free(vnet);
 891     g_free(dnssearch);
 892
 893     return ret;
 894 }
 895
 896 int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)
 897 {
 898     if (strcmp(opts_list->name, "net") != 0 ||
 899         strncmp(optarg, "channel,", strlen("channel,")) != 0) {
 900         return 0;
 901     }
 902
 903     error_report("The '-net channel' option is deprecated. "
 904                  "Please use '-netdev user,guestfwd=...' instead.");
 905
 906     /* handle legacy -net channel,port:chr */
 907     optarg += strlen("channel,");
 908
 909     if (QTAILQ_EMPTY(&slirp_stacks)) {
 910         struct slirp_config_str *config;
 911
 912         config = g_malloc(sizeof(*config));
 913         pstrcpy(config->str, sizeof(config->str), optarg);
 914         config->flags = SLIRP_CFG_LEGACY;
 915         config->next = slirp_configs;
 916         slirp_configs = config;
 917         *ret = 0;
 918     } else {
 919         *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);
 920     }
 921
 922     return 1;
 923 }
 924