Archipelago » qemu

/*

 * QEMU System Emulator

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "net/slirp.h"

#include "config-host.h"

#ifndef _WIN32

#include <pwd.h>

#include <sys/wait.h>

#endif

#include "net/net.h"

#include "clients.h"

#include "hub.h"

#include "monitor/monitor.h"

#include "qemu/sockets.h"

#include "slirp/libslirp.h"

#include "qemu-char.h"

static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)

{

    const char *p, *p1;

    int len;

    p = *pp;

    p1 = strchr(p, sep);

    if (!p1)

        return -1;

    len = p1 - p;

    p1++;

    if (buf_size > 0) {

        if (len > buf_size - 1)

            len = buf_size - 1;

        memcpy(buf, p, len);

        buf[len] = '\0';

    }

    *pp = p1;

    return 0;

}

/* slirp network adapter */

#define SLIRP_CFG_HOSTFWD 1

#define SLIRP_CFG_LEGACY  2

struct slirp_config_str {

    struct slirp_config_str *next;

    int flags;

    char str[1024];

    int legacy_format;

};

typedef struct SlirpState {

    NetClientState nc;

    QTAILQ_ENTRY(SlirpState) entry;

    Slirp *slirp;

#ifndef _WIN32

    char smb_dir[128];

#endif

} SlirpState;

static struct slirp_config_str *slirp_configs;

const char *legacy_tftp_prefix;

const char *legacy_bootp_filename;

static QTAILQ_HEAD(slirp_stacks, SlirpState) slirp_stacks =

    QTAILQ_HEAD_INITIALIZER(slirp_stacks);

static int slirp_hostfwd(SlirpState *s, const char *redir_str,

                         int legacy_format);

static int slirp_guestfwd(SlirpState *s, const char *config_str,

                          int legacy_format);

#ifndef _WIN32

static const char *legacy_smb_export;

static int slirp_smb(SlirpState *s, const char *exported_dir,

                     struct in_addr vserver_addr);

static void slirp_smb_cleanup(SlirpState *s);

#else

static inline void slirp_smb_cleanup(SlirpState *s) { }

#endif

void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)

{

    SlirpState *s = opaque;

    qemu_send_packet(&s->nc, pkt, pkt_len);

}

static ssize_t net_slirp_receive(NetClientState *nc, const uint8_t *buf, size_t size)

{

    SlirpState *s = DO_UPCAST(SlirpState, nc, nc);

    slirp_input(s->slirp, buf, size);

    return size;

}

static void net_slirp_cleanup(NetClientState *nc)

{

    SlirpState *s = DO_UPCAST(SlirpState, nc, nc);

    slirp_cleanup(s->slirp);

    slirp_smb_cleanup(s);

    QTAILQ_REMOVE(&slirp_stacks, s, entry);

}

static NetClientInfo net_slirp_info = {

    .type = NET_CLIENT_OPTIONS_KIND_USER,

    .size = sizeof(SlirpState),

    .receive = net_slirp_receive,

    .cleanup = net_slirp_cleanup,

};

static int net_slirp_init(NetClientState *peer, const char *model,

                          const char *name, int restricted,

                          const char *vnetwork, const char *vhost,

                          const char *vhostname, const char *tftp_export,

                          const char *bootfile, const char *vdhcp_start,

                          const char *vnameserver, const char *smb_export,

                          const char *vsmbserver, const char **dnssearch)

{

    /* default settings according to historic slirp */

    struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */

    struct in_addr mask = { .s_addr = htonl(0xffffff00) }; /* 255.255.255.0 */

    struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */

    struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */

    struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */

#ifndef _WIN32

    struct in_addr smbsrv = { .s_addr = 0 };

#endif

    NetClientState *nc;

    SlirpState *s;

    char buf[20];

    uint32_t addr;

    int shift;

    char *end;

    struct slirp_config_str *config;

    if (!tftp_export) {

        tftp_export = legacy_tftp_prefix;

    }

    if (!bootfile) {

        bootfile = legacy_bootp_filename;

    }

    if (vnetwork) {

        if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {

            if (!inet_aton(vnetwork, &net)) {

                return -1;

            }

            addr = ntohl(net.s_addr);

            if (!(addr & 0x80000000)) {

                mask.s_addr = htonl(0xff000000); /* class A */

            } else if ((addr & 0xfff00000) == 0xac100000) {

                mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */

            } else if ((addr & 0xc0000000) == 0x80000000) {

                mask.s_addr = htonl(0xffff0000); /* class B */

            } else if ((addr & 0xffff0000) == 0xc0a80000) {

                mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */

            } else if ((addr & 0xffff0000) == 0xc6120000) {

                mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */

            } else if ((addr & 0xe0000000) == 0xe0000000) {

                mask.s_addr = htonl(0xffffff00); /* class C */

            } else {

                mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */

            }

        } else {

            if (!inet_aton(buf, &net)) {

                return -1;

            }

            shift = strtol(vnetwork, &end, 10);

            if (*end != '\0') {

                if (!inet_aton(vnetwork, &mask)) {

                    return -1;

                }

            } else if (shift < 4 || shift > 32) {

                return -1;

            } else {

                mask.s_addr = htonl(0xffffffff << (32 - shift));

            }

        }

        net.s_addr &= mask.s_addr;

        host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);

        dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);

        dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);

    }

    if (vhost && !inet_aton(vhost, &host)) {

        return -1;

    }

    if ((host.s_addr & mask.s_addr) != net.s_addr) {

        return -1;

    }

    if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {

        return -1;

    }

    if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||

        dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {

        return -1;

    }

    if (vnameserver && !inet_aton(vnameserver, &dns)) {

        return -1;

    }

    if ((dns.s_addr & mask.s_addr) != net.s_addr ||

        dns.s_addr == host.s_addr) {

        return -1;

    }

#ifndef _WIN32

    if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {

        return -1;

    }

#endif

    nc = qemu_new_net_client(&net_slirp_info, peer, model, name);

    snprintf(nc->info_str, sizeof(nc->info_str),

             "net=%s,restrict=%s", inet_ntoa(net),

             restricted ? "on" : "off");

    s = DO_UPCAST(SlirpState, nc, nc);

    s->slirp = slirp_init(restricted, net, mask, host, vhostname,

                          tftp_export, bootfile, dhcp, dns, dnssearch, s);

    QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);

    for (config = slirp_configs; config; config = config->next) {

        if (config->flags & SLIRP_CFG_HOSTFWD) {

            if (slirp_hostfwd(s, config->str,

                              config->flags & SLIRP_CFG_LEGACY) < 0)

                goto error;

        } else {

            if (slirp_guestfwd(s, config->str,

                               config->flags & SLIRP_CFG_LEGACY) < 0)

                goto error;

        }

    }

#ifndef _WIN32

    if (!smb_export) {

        smb_export = legacy_smb_export;

    }

    if (smb_export) {

        if (slirp_smb(s, smb_export, smbsrv) < 0)

            goto error;

    }

#endif

    return 0;

error:

    qemu_del_net_client(nc);

    return -1;

}

static SlirpState *slirp_lookup(Monitor *mon, const char *vlan,

                                const char *stack)

{

    if (vlan) {

        NetClientState *nc;

        nc = net_hub_find_client_by_name(strtol(vlan, NULL, 0), stack);

        if (!nc) {

            return NULL;

        }

        if (strcmp(nc->model, "user")) {

            monitor_printf(mon, "invalid device specified\n");

            return NULL;

        }

        return DO_UPCAST(SlirpState, nc, nc);

    } else {

        if (QTAILQ_EMPTY(&slirp_stacks)) {

            monitor_printf(mon, "user mode network stack not in use\n");

            return NULL;

        }

        return QTAILQ_FIRST(&slirp_stacks);

    }

}

void net_slirp_hostfwd_remove(Monitor *mon, const QDict *qdict)

{

    struct in_addr host_addr = { .s_addr = INADDR_ANY };

    int host_port;

    char buf[256];

    const char *src_str, *p;

    SlirpState *s;

    int is_udp = 0;

    int err;

    const char *arg1 = qdict_get_str(qdict, "arg1");

    const char *arg2 = qdict_get_try_str(qdict, "arg2");

    const char *arg3 = qdict_get_try_str(qdict, "arg3");

    if (arg2) {

        s = slirp_lookup(mon, arg1, arg2);

        src_str = arg3;

    } else {

        s = slirp_lookup(mon, NULL, NULL);

        src_str = arg1;

    }

    if (!s) {

        return;

    }

    p = src_str;

    if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

        goto fail_syntax;

    }

    if (!strcmp(buf, "tcp") || buf[0] == '\0') {

        is_udp = 0;

    } else if (!strcmp(buf, "udp")) {

        is_udp = 1;

    } else {

        goto fail_syntax;

    }

    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

        goto fail_syntax;

    }

    if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {

        goto fail_syntax;

    }

    host_port = atoi(p);

    err = slirp_remove_hostfwd(QTAILQ_FIRST(&slirp_stacks)->slirp, is_udp,

                               host_addr, host_port);

    monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,

                   err ? "not found" : "removed");

    return;

 fail_syntax:

    monitor_printf(mon, "invalid format\n");

}

static int slirp_hostfwd(SlirpState *s, const char *redir_str,

                         int legacy_format)

{

    struct in_addr host_addr = { .s_addr = INADDR_ANY };

    struct in_addr guest_addr = { .s_addr = 0 };

    int host_port, guest_port;

    const char *p;

    char buf[256];

    int is_udp;

    char *end;

    p = redir_str;

    if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

        goto fail_syntax;

    }

    if (!strcmp(buf, "tcp") || buf[0] == '\0') {

        is_udp = 0;

    } else if (!strcmp(buf, "udp")) {

        is_udp = 1;

    } else {

        goto fail_syntax;

    }

    if (!legacy_format) {

        if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

            goto fail_syntax;

        }

        if (buf[0] != '\0' && !inet_aton(buf, &host_addr)) {

            goto fail_syntax;

        }

    }

    if (get_str_sep(buf, sizeof(buf), &p, legacy_format ? ':' : '-') < 0) {

        goto fail_syntax;

    }

    host_port = strtol(buf, &end, 0);

    if (*end != '\0' || host_port < 1 || host_port > 65535) {

        goto fail_syntax;

    }

    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

        goto fail_syntax;

    }

    if (buf[0] != '\0' && !inet_aton(buf, &guest_addr)) {

        goto fail_syntax;

    }

    guest_port = strtol(p, &end, 0);

    if (*end != '\0' || guest_port < 1 || guest_port > 65535) {

        goto fail_syntax;

    }

    if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,

                          guest_port) < 0) {

        error_report("could not set up host forwarding rule '%s'",

                     redir_str);

        return -1;

    }

    return 0;

 fail_syntax:

    error_report("invalid host forwarding rule '%s'", redir_str);

    return -1;

}

void net_slirp_hostfwd_add(Monitor *mon, const QDict *qdict)

{

    const char *redir_str;

    SlirpState *s;

    const char *arg1 = qdict_get_str(qdict, "arg1");

    const char *arg2 = qdict_get_try_str(qdict, "arg2");

    const char *arg3 = qdict_get_try_str(qdict, "arg3");

    if (arg2) {

        s = slirp_lookup(mon, arg1, arg2);

        redir_str = arg3;

    } else {

        s = slirp_lookup(mon, NULL, NULL);

        redir_str = arg1;

    }

    if (s) {

        slirp_hostfwd(s, redir_str, 0);

    }

}

int net_slirp_redir(const char *redir_str)

{

    struct slirp_config_str *config;

    if (QTAILQ_EMPTY(&slirp_stacks)) {

        config = g_malloc(sizeof(*config));

        pstrcpy(config->str, sizeof(config->str), redir_str);

        config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;

        config->next = slirp_configs;

        slirp_configs = config;

        return 0;

    }

    return slirp_hostfwd(QTAILQ_FIRST(&slirp_stacks), redir_str, 1);

}

#ifndef _WIN32

/* automatic user mode samba server configuration */

static void slirp_smb_cleanup(SlirpState *s)

{

    char cmd[128];

    int ret;

    if (s->smb_dir[0] != '\0') {

        snprintf(cmd, sizeof(cmd), "rm -rf %s", s->smb_dir);

        ret = system(cmd);

        if (ret == -1 || !WIFEXITED(ret)) {

            error_report("'%s' failed.", cmd);

        } else if (WEXITSTATUS(ret)) {

            error_report("'%s' failed. Error code: %d",

                         cmd, WEXITSTATUS(ret));

        }

        s->smb_dir[0] = '\0';

    }

}

static int slirp_smb(SlirpState* s, const char *exported_dir,

                     struct in_addr vserver_addr)

{

    static int instance;

    char smb_conf[128];

    char smb_cmdline[128];

    struct passwd *passwd;

    FILE *f;

    passwd = getpwuid(geteuid());

    if (!passwd) {

        error_report("failed to retrieve user name");

        return -1;

    }

    if (access(CONFIG_SMBD_COMMAND, F_OK)) {

        error_report("could not find '%s', please install it",

                     CONFIG_SMBD_COMMAND);

        return -1;

    }

    if (access(exported_dir, R_OK | X_OK)) {

        error_report("error accessing shared directory '%s': %s",

                     exported_dir, strerror(errno));

        return -1;

    }

    snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.%ld-%d",

             (long)getpid(), instance++);

    if (mkdir(s->smb_dir, 0700) < 0) {

        error_report("could not create samba server dir '%s'", s->smb_dir);

        return -1;

    }

    snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");

    f = fopen(smb_conf, "w");

    if (!f) {

        slirp_smb_cleanup(s);

        error_report("could not create samba server configuration file '%s'",

                     smb_conf);

        return -1;

    }

    fprintf(f,

            "[global]\n"

            "private dir=%s\n"

            "socket address=127.0.0.1\n"

            "pid directory=%s\n"

            "lock directory=%s\n"

            "state directory=%s\n"

            "log file=%s/log.smbd\n"

            "smb passwd file=%s/smbpasswd\n"

            "security = share\n"

            "[qemu]\n"

            "path=%s\n"

            "read only=no\n"

            "guest ok=yes\n"

            "force user=%s\n",

            s->smb_dir,

            s->smb_dir,

            s->smb_dir,

            s->smb_dir,

            s->smb_dir,

            s->smb_dir,

            exported_dir,

            passwd->pw_name

            );

    fclose(f);

    snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -s %s",

             CONFIG_SMBD_COMMAND, smb_conf);

    if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0) {

        slirp_smb_cleanup(s);

        error_report("conflicting/invalid smbserver address");

        return -1;

    }

    return 0;

}

/* automatic user mode samba server configuration (legacy interface) */

int net_slirp_smb(const char *exported_dir)

{

    struct in_addr vserver_addr = { .s_addr = 0 };

    if (legacy_smb_export) {

        fprintf(stderr, "-smb given twice\n");

        return -1;

    }

    legacy_smb_export = exported_dir;

    if (!QTAILQ_EMPTY(&slirp_stacks)) {

        return slirp_smb(QTAILQ_FIRST(&slirp_stacks), exported_dir,

                         vserver_addr);

    }

    return 0;

}

#endif /* !defined(_WIN32) */

struct GuestFwd {

    CharDriverState *hd;

    struct in_addr server;

    int port;

    Slirp *slirp;

};

static int guestfwd_can_read(void *opaque)

{

    struct GuestFwd *fwd = opaque;

    return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);

}

static void guestfwd_read(void *opaque, const uint8_t *buf, int size)

{

    struct GuestFwd *fwd = opaque;

    slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);

}

static int slirp_guestfwd(SlirpState *s, const char *config_str,

                          int legacy_format)

{

    struct in_addr server = { .s_addr = 0 };

    struct GuestFwd *fwd;

    const char *p;

    char buf[128];

    char *end;

    int port;

    p = config_str;

    if (legacy_format) {

        if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

            goto fail_syntax;

        }

    } else {

        if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

            goto fail_syntax;

        }

        if (strcmp(buf, "tcp") && buf[0] != '\0') {

            goto fail_syntax;

        }

        if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {

            goto fail_syntax;

        }

        if (buf[0] != '\0' && !inet_aton(buf, &server)) {

            goto fail_syntax;

        }

        if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {

            goto fail_syntax;

        }

    }

    port = strtol(buf, &end, 10);

    if (*end != '\0' || port < 1 || port > 65535) {

        goto fail_syntax;

    }

    fwd = g_malloc(sizeof(struct GuestFwd));

    snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port);

    if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) {

        if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) {

            error_report("conflicting/invalid host:port in guest forwarding "

                         "rule '%s'", config_str);

            g_free(fwd);

            return -1;

        }

    } else {

        fwd->hd = qemu_chr_new(buf, p, NULL);

        if (!fwd->hd) {

            error_report("could not open guest forwarding device '%s'", buf);

            g_free(fwd);

            return -1;

        }

        if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) {

            error_report("conflicting/invalid host:port in guest forwarding "

                         "rule '%s'", config_str);

            g_free(fwd);

            return -1;

        }

        fwd->server = server;

        fwd->port = port;

        fwd->slirp = s->slirp;

        qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read,

                              NULL, fwd);

    }

    return 0;

 fail_syntax:

    error_report("invalid guest forwarding rule '%s'", config_str);

    return -1;

}

void do_info_usernet(Monitor *mon)

{

    SlirpState *s;

    QTAILQ_FOREACH(s, &slirp_stacks, entry) {

        int id;

        bool got_vlan_id = net_hub_id_for_client(&s->nc, &id) == 0;

        monitor_printf(mon, "VLAN %d (%s):\n",

                       got_vlan_id ? id : -1,

                       s->nc.name);

        slirp_connection_info(s->slirp, mon);

    }

}

static void

net_init_slirp_configs(const StringList *fwd, int flags)

{

    while (fwd) {

        struct slirp_config_str *config;

        config = g_malloc0(sizeof(*config));

        pstrcpy(config->str, sizeof(config->str), fwd->value->str);

        config->flags = flags;

        config->next = slirp_configs;

        slirp_configs = config;

        fwd = fwd->next;

    }

}

static const char **slirp_dnssearch(const StringList *dnsname)

{

    const StringList *c = dnsname;

    size_t i = 0, num_opts = 0;

    const char **ret;

    while (c) {

        num_opts++;

        c = c->next;

    }

    if (num_opts == 0) {

        return NULL;

    }

    ret = g_malloc((num_opts + 1) * sizeof(*ret));

    c = dnsname;

    while (c) {

        ret[i++] = c->value->str;

        c = c->next;

    }

    ret[i] = NULL;

    return ret;

}

int net_init_slirp(const NetClientOptions *opts, const char *name,

                   NetClientState *peer)

{

    struct slirp_config_str *config;

    char *vnet;

    int ret;

    const NetdevUserOptions *user;

    const char **dnssearch;

    assert(opts->kind == NET_CLIENT_OPTIONS_KIND_USER);

    user = opts->user;

    vnet = user->has_net ? g_strdup(user->net) :

           user->has_ip  ? g_strdup_printf("%s/24", user->ip) :

           NULL;

    dnssearch = slirp_dnssearch(user->dnssearch);

    /* all optional fields are initialized to "all bits zero" */

    net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);

    net_init_slirp_configs(user->guestfwd, 0);

    ret = net_slirp_init(peer, "user", name, user->q_restrict, vnet,

                         user->host, user->hostname, user->tftp,

                         user->bootfile, user->dhcpstart, user->dns, user->smb,

                         user->smbserver, dnssearch);

    while (slirp_configs) {

        config = slirp_configs;

        slirp_configs = config->next;

        g_free(config);

    }

    g_free(vnet);

    g_free(dnssearch);

    return ret;

}

int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret)

{

    if (strcmp(opts_list->name, "net") != 0 ||

        strncmp(optarg, "channel,", strlen("channel,")) != 0) {

        return 0;

    }

    /* handle legacy -net channel,port:chr */

    optarg += strlen("channel,");

    if (QTAILQ_EMPTY(&slirp_stacks)) {

        struct slirp_config_str *config;

        config = g_malloc(sizeof(*config));

        pstrcpy(config->str, sizeof(config->str), optarg);

        config->flags = SLIRP_CFG_LEGACY;

        config->next = slirp_configs;

        slirp_configs = config;

        *ret = 0;

    } else {

        *ret = slirp_guestfwd(QTAILQ_FIRST(&slirp_stacks), optarg, 1);

    }

    return 1;

}