Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 805 insertions, 0 deletions

diff --git a/qemu/net/slirp.c b/qemu/net/slirp.c
new file mode 100644
index 000000000..7657b38fd
--- /dev/null
+++ b/qemu/net/slirp.c
@@ -0,0 +1,805 @@
+/*
+ * 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/error-report.h"
+#include "qemu/sockets.h"
+#include "slirp/libslirp.h"
+#include "sysemu/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 (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;
+    }
+
+    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;
+    }
+
+#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) {
+            monitor_printf(mon, "unrecognized (vlan-id, stackname) pair\n");
+            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 hmp_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(s->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 hmp_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)
+{
+    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.XXXXXX");
+    if (!mkdtemp(s->smb_dir)) {
+        error_report("could not create samba server dir '%s'", s->smb_dir);
+        s->smb_dir[0] = 0;
+        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"
+            "interfaces=127.0.0.1\n"
+            "bind interfaces only=yes\n"
+            "pid directory=%s\n"
+            "lock directory=%s\n"
+            "state directory=%s\n"
+            "cache directory=%s\n"
+            "ncalrpc dir=%s/ncalrpc\n"
+            "log file=%s/log.smbd\n"
+            "smb passwd file=%s/smbpasswd\n"
+            "security = user\n"
+            "map to guest = Bad User\n"
+            "load printers = no\n"
+            "printing = bsd\n"
+            "disable spoolss = yes\n"
+            "usershare max shares = 0\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,
+            s->smb_dir,
+            s->smb_dir,
+            exported_dir,
+            passwd->pw_name
+            );
+    fclose(f);
+
+    snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -l %s -s %s",
+             CONFIG_SMBD_COMMAND, s->smb_dir, smb_conf);
+
+    if (slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 139) < 0 ||
+        slirp_add_exec(s->slirp, 0, smb_cmdline, &vserver_addr, 445) < 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;
+    }
+
+    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);
+            return -1;
+        }
+    } else {
+        fwd = g_new(struct GuestFwd, 1);
+        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_fe_claim_no_fail(fwd->hd);
+        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 hmp_info_usernet(Monitor *mon, const QDict *qdict)
+{
+    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, Error **errp)
+{
+    /* FIXME error_setg(errp, ...) on failure */
+    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;
+}
+