Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 1482 insertions, 0 deletions

diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
new file mode 100644
index 000000000..0585e7a62
--- /dev/null
+++ b/util/qemu-sockets.c
@@ -0,0 +1,1482 @@
+/*
+ *  inet and unix socket functions for qemu
+ *
+ *  (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+#include "qemu/osdep.h"
+
+#ifdef CONFIG_AF_VSOCK
+#include <linux/vm_sockets.h>
+#endif /* CONFIG_AF_VSOCK */
+
+#include "qemu-common.h"
+#include "monitor/monitor.h"
+#include "qapi/clone-visitor.h"
+#include "qapi/error.h"
+#include "qapi/qapi-visit-sockets.h"
+#include "qemu/sockets.h"
+#include "qemu/main-loop.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/qobject-output-visitor.h"
+#include "qemu/cutils.h"
+#include "trace.h"
+
+#ifndef AI_ADDRCONFIG
+# define AI_ADDRCONFIG 0
+#endif
+
+#ifndef AI_V4MAPPED
+# define AI_V4MAPPED 0
+#endif
+
+#ifndef AI_NUMERICSERV
+# define AI_NUMERICSERV 0
+#endif
+
+
+static int inet_getport(struct addrinfo *e)
+{
+    struct sockaddr_in *i4;
+    struct sockaddr_in6 *i6;
+
+    switch (e->ai_family) {
+    case PF_INET6:
+        i6 = (void*)e->ai_addr;
+        return ntohs(i6->sin6_port);
+    case PF_INET:
+        i4 = (void*)e->ai_addr;
+        return ntohs(i4->sin_port);
+    default:
+        return 0;
+    }
+}
+
+static void inet_setport(struct addrinfo *e, int port)
+{
+    struct sockaddr_in *i4;
+    struct sockaddr_in6 *i6;
+
+    switch (e->ai_family) {
+    case PF_INET6:
+        i6 = (void*)e->ai_addr;
+        i6->sin6_port = htons(port);
+        break;
+    case PF_INET:
+        i4 = (void*)e->ai_addr;
+        i4->sin_port = htons(port);
+        break;
+    }
+}
+
+NetworkAddressFamily inet_netfamily(int family)
+{
+    switch (family) {
+    case PF_INET6: return NETWORK_ADDRESS_FAMILY_IPV6;
+    case PF_INET:  return NETWORK_ADDRESS_FAMILY_IPV4;
+    case PF_UNIX:  return NETWORK_ADDRESS_FAMILY_UNIX;
+#ifdef CONFIG_AF_VSOCK
+    case PF_VSOCK: return NETWORK_ADDRESS_FAMILY_VSOCK;
+#endif /* CONFIG_AF_VSOCK */
+    }
+    return NETWORK_ADDRESS_FAMILY_UNKNOWN;
+}
+
+bool fd_is_socket(int fd)
+{
+    int optval;
+    socklen_t optlen = sizeof(optval);
+    return !qemu_getsockopt(fd, SOL_SOCKET, SO_TYPE, &optval, &optlen);
+}
+
+
+/*
+ * Matrix we're trying to apply
+ *
+ *  ipv4  ipv6   family
+ *   -     -       PF_UNSPEC
+ *   -     f       PF_INET
+ *   -     t       PF_INET6
+ *   f     -       PF_INET6
+ *   f     f       <error>
+ *   f     t       PF_INET6
+ *   t     -       PF_INET
+ *   t     f       PF_INET
+ *   t     t       PF_INET6/PF_UNSPEC
+ *
+ * NB, this matrix is only about getting the necessary results
+ * from getaddrinfo(). Some of the cases require further work
+ * after reading results from getaddrinfo in order to fully
+ * apply the logic the end user wants.
+ *
+ * In the first and last cases, we must set IPV6_V6ONLY=0
+ * when binding, to allow a single listener to potentially
+ * accept both IPv4+6 addresses.
+ */
+int inet_ai_family_from_address(InetSocketAddress *addr,
+                                Error **errp)
+{
+    if (addr->has_ipv6 && addr->has_ipv4 &&
+        !addr->ipv6 && !addr->ipv4) {
+        error_setg(errp, "Cannot disable IPv4 and IPv6 at same time");
+        return PF_UNSPEC;
+    }
+    if ((addr->has_ipv6 && addr->ipv6) && (addr->has_ipv4 && addr->ipv4)) {
+        /*
+         * Some backends can only do a single listener. In that case
+         * we want empty hostname to resolve to "::" and then use the
+         * flag IPV6_V6ONLY==0 to get both protocols on 1 socket. This
+         * doesn't work for addresses other than "", so they're just
+         * inevitably broken until multiple listeners can be used,
+         * and thus we honour getaddrinfo automatic protocol detection
+         * Once all backends do multi-listener, remove the PF_INET6
+         * branch entirely.
+         */
+        if (!addr->host || g_str_equal(addr->host, "")) {
+            return PF_INET6;
+        } else {
+            return PF_UNSPEC;
+        }
+    }
+    if ((addr->has_ipv6 && addr->ipv6) || (addr->has_ipv4 && !addr->ipv4)) {
+        return PF_INET6;
+    }
+    if ((addr->has_ipv4 && addr->ipv4) || (addr->has_ipv6 && !addr->ipv6)) {
+        return PF_INET;
+    }
+    return PF_UNSPEC;
+}
+
+static int create_fast_reuse_socket(struct addrinfo *e)
+{
+    int slisten = qemu_socket(e->ai_family, e->ai_socktype, e->ai_protocol);
+    if (slisten < 0) {
+        return -1;
+    }
+    socket_set_fast_reuse(slisten);
+    return slisten;
+}
+
+static int try_bind(int socket, InetSocketAddress *saddr, struct addrinfo *e)
+{
+#ifndef IPV6_V6ONLY
+    return bind(socket, e->ai_addr, e->ai_addrlen);
+#else
+    /*
+     * Deals with first & last cases in matrix in comment
+     * for inet_ai_family_from_address().
+     */
+    int v6only =
+        ((!saddr->has_ipv4 && !saddr->has_ipv6) ||
+         (saddr->has_ipv4 && saddr->ipv4 &&
+          saddr->has_ipv6 && saddr->ipv6)) ? 0 : 1;
+    int stat;
+
+ rebind:
+    if (e->ai_family == PF_INET6) {
+        qemu_setsockopt(socket, IPPROTO_IPV6, IPV6_V6ONLY, &v6only,
+                        sizeof(v6only));
+    }
+
+    stat = bind(socket, e->ai_addr, e->ai_addrlen);
+    if (!stat) {
+        return 0;
+    }
+
+    /* If we got EADDRINUSE from an IPv6 bind & v6only is unset,
+     * it could be that the IPv4 port is already claimed, so retry
+     * with v6only set
+     */
+    if (e->ai_family == PF_INET6 && errno == EADDRINUSE && !v6only) {
+        v6only = 1;
+        goto rebind;
+    }
+    return stat;
+#endif
+}
+
+static int inet_listen_saddr(InetSocketAddress *saddr,
+                             int port_offset,
+                             int num,
+                             Error **errp)
+{
+    struct addrinfo ai,*res,*e;
+    char port[33];
+    char uaddr[INET6_ADDRSTRLEN+1];
+    char uport[33];
+    int rc, port_min, port_max, p;
+    int slisten = -1;
+    int saved_errno = 0;
+    bool socket_created = false;
+    Error *err = NULL;
+
+    if (saddr->keep_alive) {
+        error_setg(errp, "keep-alive option is not supported for passive "
+                   "sockets");
+        return -1;
+    }
+
+    memset(&ai,0, sizeof(ai));
+    ai.ai_flags = AI_PASSIVE;
+    if (saddr->has_numeric && saddr->numeric) {
+        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
+    }
+    ai.ai_family = inet_ai_family_from_address(saddr, &err);
+    ai.ai_socktype = SOCK_STREAM;
+
+    if (err) {
+        error_propagate(errp, err);
+        return -1;
+    }
+
+    if (saddr->host == NULL) {
+        error_setg(errp, "host not specified");
+        return -1;
+    }
+    if (saddr->port != NULL) {
+        pstrcpy(port, sizeof(port), saddr->port);
+    } else {
+        port[0] = '\0';
+    }
+
+    /* lookup */
+    if (port_offset) {
+        unsigned long long baseport;
+        if (strlen(port) == 0) {
+            error_setg(errp, "port not specified");
+            return -1;
+        }
+        if (parse_uint_full(port, &baseport, 10) < 0) {
+            error_setg(errp, "can't convert to a number: %s", port);
+            return -1;
+        }
+        if (baseport > 65535 ||
+            baseport + port_offset > 65535) {
+            error_setg(errp, "port %s out of range", port);
+            return -1;
+        }
+        snprintf(port, sizeof(port), "%d", (int)baseport + port_offset);
+    }
+    rc = getaddrinfo(strlen(saddr->host) ? saddr->host : NULL,
+                     strlen(port) ? port : NULL, &ai, &res);
+    if (rc != 0) {
+        error_setg(errp, "address resolution failed for %s:%s: %s",
+                   saddr->host, port, gai_strerror(rc));
+        return -1;
+    }
+
+    /* create socket + bind/listen */
+    for (e = res; e != NULL; e = e->ai_next) {
+#ifdef HAVE_IPPROTO_MPTCP
+        if (saddr->has_mptcp && saddr->mptcp) {
+            e->ai_protocol = IPPROTO_MPTCP;
+        }
+#endif
+        getnameinfo((struct sockaddr*)e->ai_addr,e->ai_addrlen,
+                        uaddr,INET6_ADDRSTRLEN,uport,32,
+                        NI_NUMERICHOST | NI_NUMERICSERV);
+
+        port_min = inet_getport(e);
+        port_max = saddr->has_to ? saddr->to + port_offset : port_min;
+        for (p = port_min; p <= port_max; p++) {
+            inet_setport(e, p);
+
+            slisten = create_fast_reuse_socket(e);
+            if (slisten < 0) {
+                /* First time we expect we might fail to create the socket
+                 * eg if 'e' has AF_INET6 but ipv6 kmod is not loaded.
+                 * Later iterations should always succeed if first iteration
+                 * worked though, so treat that as fatal.
+                 */
+                if (p == port_min) {
+                    continue;
+                } else {
+                    error_setg_errno(errp, errno,
+                                     "Failed to recreate failed listening socket");
+                    goto listen_failed;
+                }
+            }
+            socket_created = true;
+
+            rc = try_bind(slisten, saddr, e);
+            if (rc < 0) {
+                if (errno != EADDRINUSE) {
+                    error_setg_errno(errp, errno, "Failed to bind socket");
+                    goto listen_failed;
+                }
+            } else {
+                if (!listen(slisten, num)) {
+                    goto listen_ok;
+                }
+                if (errno != EADDRINUSE) {
+                    error_setg_errno(errp, errno, "Failed to listen on socket");
+                    goto listen_failed;
+                }
+            }
+            /* Someone else managed to bind to the same port and beat us
+             * to listen on it! Socket semantics does not allow us to
+             * recover from this situation, so we need to recreate the
+             * socket to allow bind attempts for subsequent ports:
+             */
+            closesocket(slisten);
+            slisten = -1;
+        }
+    }
+    error_setg_errno(errp, errno,
+                     socket_created ?
+                     "Failed to find an available port" :
+                     "Failed to create a socket");
+listen_failed:
+    saved_errno = errno;
+    if (slisten >= 0) {
+        closesocket(slisten);
+    }
+    freeaddrinfo(res);
+    errno = saved_errno;
+    return -1;
+
+listen_ok:
+    freeaddrinfo(res);
+    return slisten;
+}
+
+#ifdef _WIN32
+#define QEMU_SOCKET_RC_INPROGRESS(rc) \
+    ((rc) == -EINPROGRESS || (rc) == -EWOULDBLOCK || (rc) == -WSAEALREADY)
+#else
+#define QEMU_SOCKET_RC_INPROGRESS(rc) \
+    ((rc) == -EINPROGRESS)
+#endif
+
+static int inet_connect_addr(const InetSocketAddress *saddr,
+                             struct addrinfo *addr, Error **errp)
+{
+    int sock, rc;
+
+    sock = qemu_socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
+    if (sock < 0) {
+        error_setg_errno(errp, errno, "Failed to create socket family %d",
+                         addr->ai_family);
+        return -1;
+    }
+    socket_set_fast_reuse(sock);
+
+    /* connect to peer */
+    do {
+        rc = 0;
+        if (connect(sock, addr->ai_addr, addr->ai_addrlen) < 0) {
+            rc = -errno;
+        }
+    } while (rc == -EINTR);
+
+    if (rc < 0) {
+        error_setg_errno(errp, errno, "Failed to connect to '%s:%s'",
+                         saddr->host, saddr->port);
+        closesocket(sock);
+        return -1;
+    }
+
+    return sock;
+}
+
+static struct addrinfo *inet_parse_connect_saddr(InetSocketAddress *saddr,
+                                                 Error **errp)
+{
+    struct addrinfo ai, *res;
+    int rc;
+    Error *err = NULL;
+    static int useV4Mapped = 1;
+
+    memset(&ai, 0, sizeof(ai));
+
+    ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
+    if (qatomic_read(&useV4Mapped)) {
+        ai.ai_flags |= AI_V4MAPPED;
+    }
+    ai.ai_family = inet_ai_family_from_address(saddr, &err);
+    ai.ai_socktype = SOCK_STREAM;
+
+    if (err) {
+        error_propagate(errp, err);
+        return NULL;
+    }
+
+    if (saddr->host == NULL || saddr->port == NULL) {
+        error_setg(errp, "host and/or port not specified");
+        return NULL;
+    }
+
+    /* lookup */
+    rc = getaddrinfo(saddr->host, saddr->port, &ai, &res);
+
+    /* At least FreeBSD and OS-X 10.6 declare AI_V4MAPPED but
+     * then don't implement it in their getaddrinfo(). Detect
+     * this and retry without the flag since that's preferable
+     * to a fatal error
+     */
+    if (rc == EAI_BADFLAGS &&
+        (ai.ai_flags & AI_V4MAPPED)) {
+        qatomic_set(&useV4Mapped, 0);
+        ai.ai_flags &= ~AI_V4MAPPED;
+        rc = getaddrinfo(saddr->host, saddr->port, &ai, &res);
+    }
+    if (rc != 0) {
+        error_setg(errp, "address resolution failed for %s:%s: %s",
+                   saddr->host, saddr->port, gai_strerror(rc));
+        return NULL;
+    }
+    return res;
+}
+
+/**
+ * Create a socket and connect it to an address.
+ *
+ * @saddr: Inet socket address specification
+ * @errp: set on error
+ *
+ * Returns: -1 on error, file descriptor on success.
+ */
+int inet_connect_saddr(InetSocketAddress *saddr, Error **errp)
+{
+    Error *local_err = NULL;
+    struct addrinfo *res, *e;
+    int sock = -1;
+
+    res = inet_parse_connect_saddr(saddr, errp);
+    if (!res) {
+        return -1;
+    }
+
+    for (e = res; e != NULL; e = e->ai_next) {
+        error_free(local_err);
+        local_err = NULL;
+
+#ifdef HAVE_IPPROTO_MPTCP
+        if (saddr->has_mptcp && saddr->mptcp) {
+            e->ai_protocol = IPPROTO_MPTCP;
+        }
+#endif
+
+        sock = inet_connect_addr(saddr, e, &local_err);
+        if (sock >= 0) {
+            break;
+        }
+    }
+
+    freeaddrinfo(res);
+
+    if (sock < 0) {
+        error_propagate(errp, local_err);
+        return sock;
+    }
+
+    if (saddr->keep_alive) {
+        int val = 1;
+        int ret = qemu_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
+                                  &val, sizeof(val));
+
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "Unable to set KEEPALIVE");
+            close(sock);
+            return -1;
+        }
+    }
+
+    return sock;
+}
+
+static int inet_dgram_saddr(InetSocketAddress *sraddr,
+                            InetSocketAddress *sladdr,
+                            Error **errp)
+{
+    struct addrinfo ai, *peer = NULL, *local = NULL;
+    const char *addr;
+    const char *port;
+    int sock = -1, rc;
+    Error *err = NULL;
+
+    /* lookup peer addr */
+    memset(&ai,0, sizeof(ai));
+    ai.ai_flags = AI_CANONNAME | AI_V4MAPPED | AI_ADDRCONFIG;
+    ai.ai_family = inet_ai_family_from_address(sraddr, &err);
+    ai.ai_socktype = SOCK_DGRAM;
+
+    if (err) {
+        error_propagate(errp, err);
+        goto err;
+    }
+
+    addr = sraddr->host;
+    port = sraddr->port;
+    if (addr == NULL || strlen(addr) == 0) {
+        addr = "localhost";
+    }
+    if (port == NULL || strlen(port) == 0) {
+        error_setg(errp, "remote port not specified");
+        goto err;
+    }
+
+    if ((rc = getaddrinfo(addr, port, &ai, &peer)) != 0) {
+        error_setg(errp, "address resolution failed for %s:%s: %s", addr, port,
+                   gai_strerror(rc));
+        goto err;
+    }
+
+    /* lookup local addr */
+    memset(&ai,0, sizeof(ai));
+    ai.ai_flags = AI_PASSIVE;
+    ai.ai_family = peer->ai_family;
+    ai.ai_socktype = SOCK_DGRAM;
+
+    if (sladdr) {
+        addr = sladdr->host;
+        port = sladdr->port;
+        if (addr == NULL || strlen(addr) == 0) {
+            addr = NULL;
+        }
+        if (!port || strlen(port) == 0) {
+            port = "0";
+        }
+    } else {
+        addr = NULL;
+        port = "0";
+    }
+
+    if ((rc = getaddrinfo(addr, port, &ai, &local)) != 0) {
+        error_setg(errp, "address resolution failed for %s:%s: %s", addr, port,
+                   gai_strerror(rc));
+        goto err;
+    }
+
+    /* create socket */
+    sock = qemu_socket(peer->ai_family, peer->ai_socktype, peer->ai_protocol);
+    if (sock < 0) {
+        error_setg_errno(errp, errno, "Failed to create socket family %d",
+                         peer->ai_family);
+        goto err;
+    }
+    socket_set_fast_reuse(sock);
+
+    /* bind socket */
+    if (bind(sock, local->ai_addr, local->ai_addrlen) < 0) {
+        error_setg_errno(errp, errno, "Failed to bind socket");
+        goto err;
+    }
+
+    /* connect to peer */
+    if (connect(sock,peer->ai_addr,peer->ai_addrlen) < 0) {
+        error_setg_errno(errp, errno, "Failed to connect to '%s:%s'",
+                         addr, port);
+        goto err;
+    }
+
+    freeaddrinfo(local);
+    freeaddrinfo(peer);
+    return sock;
+
+err:
+    if (sock != -1) {
+        closesocket(sock);
+    }
+    if (local) {
+        freeaddrinfo(local);
+    }
+    if (peer) {
+        freeaddrinfo(peer);
+    }
+
+    return -1;
+}
+
+/* compatibility wrapper */
+static int inet_parse_flag(const char *flagname, const char *optstr, bool *val,
+                           Error **errp)
+{
+    char *end;
+    size_t len;
+
+    end = strstr(optstr, ",");
+    if (end) {
+        if (end[1] == ',') { /* Reject 'ipv6=on,,foo' */
+            error_setg(errp, "error parsing '%s' flag '%s'", flagname, optstr);
+            return -1;
+        }
+        len = end - optstr;
+    } else {
+        len = strlen(optstr);
+    }
+    if (len == 0 || (len == 3 && strncmp(optstr, "=on", len) == 0)) {
+        *val = true;
+    } else if (len == 4 && strncmp(optstr, "=off", len) == 0) {
+        *val = false;
+    } else {
+        error_setg(errp, "error parsing '%s' flag '%s'", flagname, optstr);
+        return -1;
+    }
+    return 0;
+}
+
+int inet_parse(InetSocketAddress *addr, const char *str, Error **errp)
+{
+    const char *optstr, *h;
+    char host[65];
+    char port[33];
+    int to;
+    int pos;
+    char *begin;
+
+    memset(addr, 0, sizeof(*addr));
+
+    /* parse address */
+    if (str[0] == ':') {
+        /* no host given */
+        host[0] = '\0';
+        if (sscanf(str, ":%32[^,]%n", port, &pos) != 1) {
+            error_setg(errp, "error parsing port in address '%s'", str);
+            return -1;
+        }
+    } else if (str[0] == '[') {
+        /* IPv6 addr */
+        if (sscanf(str, "[%64[^]]]:%32[^,]%n", host, port, &pos) != 2) {
+            error_setg(errp, "error parsing IPv6 address '%s'", str);
+            return -1;
+        }
+    } else {
+        /* hostname or IPv4 addr */
+        if (sscanf(str, "%64[^:]:%32[^,]%n", host, port, &pos) != 2) {
+            error_setg(errp, "error parsing address '%s'", str);
+            return -1;
+        }
+    }
+
+    addr->host = g_strdup(host);
+    addr->port = g_strdup(port);
+
+    /* parse options */
+    optstr = str + pos;
+    h = strstr(optstr, ",to=");
+    if (h) {
+        h += 4;
+        if (sscanf(h, "%d%n", &to, &pos) != 1 ||
+            (h[pos] != '\0' && h[pos] != ',')) {
+            error_setg(errp, "error parsing to= argument");
+            return -1;
+        }
+        addr->has_to = true;
+        addr->to = to;
+    }
+    begin = strstr(optstr, ",ipv4");
+    if (begin) {
+        if (inet_parse_flag("ipv4", begin + 5, &addr->ipv4, errp) < 0) {
+            return -1;
+        }
+        addr->has_ipv4 = true;
+    }
+    begin = strstr(optstr, ",ipv6");
+    if (begin) {
+        if (inet_parse_flag("ipv6", begin + 5, &addr->ipv6, errp) < 0) {
+            return -1;
+        }
+        addr->has_ipv6 = true;
+    }
+    begin = strstr(optstr, ",keep-alive");
+    if (begin) {
+        if (inet_parse_flag("keep-alive", begin + strlen(",keep-alive"),
+                            &addr->keep_alive, errp) < 0)
+        {
+            return -1;
+        }
+        addr->has_keep_alive = true;
+    }
+#ifdef HAVE_IPPROTO_MPTCP
+    begin = strstr(optstr, ",mptcp");
+    if (begin) {
+        if (inet_parse_flag("mptcp", begin + strlen(",mptcp"),
+                            &addr->mptcp, errp) < 0)
+        {
+            return -1;
+        }
+        addr->has_mptcp = true;
+    }
+#endif
+    return 0;
+}
+
+
+/**
+ * Create a blocking socket and connect it to an address.
+ *
+ * @str: address string
+ * @errp: set in case of an error
+ *
+ * Returns -1 in case of error, file descriptor on success
+ **/
+int inet_connect(const char *str, Error **errp)
+{
+    int sock = -1;
+    InetSocketAddress *addr = g_new(InetSocketAddress, 1);
+
+    if (!inet_parse(addr, str, errp)) {
+        sock = inet_connect_saddr(addr, errp);
+    }
+    qapi_free_InetSocketAddress(addr);
+    return sock;
+}
+
+#ifdef CONFIG_AF_VSOCK
+static bool vsock_parse_vaddr_to_sockaddr(const VsockSocketAddress *vaddr,
+                                          struct sockaddr_vm *svm,
+                                          Error **errp)
+{
+    unsigned long long val;
+
+    memset(svm, 0, sizeof(*svm));
+    svm->svm_family = AF_VSOCK;
+
+    if (parse_uint_full(vaddr->cid, &val, 10) < 0 ||
+        val > UINT32_MAX) {
+        error_setg(errp, "Failed to parse cid '%s'", vaddr->cid);
+        return false;
+    }
+    svm->svm_cid = val;
+
+    if (parse_uint_full(vaddr->port, &val, 10) < 0 ||
+        val > UINT32_MAX) {
+        error_setg(errp, "Failed to parse port '%s'", vaddr->port);
+        return false;
+    }
+    svm->svm_port = val;
+
+    return true;
+}
+
+static int vsock_connect_addr(const VsockSocketAddress *vaddr,
+                              const struct sockaddr_vm *svm, Error **errp)
+{
+    int sock, rc;
+
+    sock = qemu_socket(AF_VSOCK, SOCK_STREAM, 0);
+    if (sock < 0) {
+        error_setg_errno(errp, errno, "Failed to create socket family %d",
+                         AF_VSOCK);
+        return -1;
+    }
+
+    /* connect to peer */
+    do {
+        rc = 0;
+        if (connect(sock, (const struct sockaddr *)svm, sizeof(*svm)) < 0) {
+            rc = -errno;
+        }
+    } while (rc == -EINTR);
+
+    if (rc < 0) {
+        error_setg_errno(errp, errno, "Failed to connect to '%s:%s'",
+                         vaddr->cid, vaddr->port);
+        closesocket(sock);
+        return -1;
+    }
+
+    return sock;
+}
+
+static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp)
+{
+    struct sockaddr_vm svm;
+
+    if (!vsock_parse_vaddr_to_sockaddr(vaddr, &svm, errp)) {
+        return -1;
+    }
+
+    return vsock_connect_addr(vaddr, &svm, errp);
+}
+
+static int vsock_listen_saddr(VsockSocketAddress *vaddr,
+                              int num,
+                              Error **errp)
+{
+    struct sockaddr_vm svm;
+    int slisten;
+
+    if (!vsock_parse_vaddr_to_sockaddr(vaddr, &svm, errp)) {
+        return -1;
+    }
+
+    slisten = qemu_socket(AF_VSOCK, SOCK_STREAM, 0);
+    if (slisten < 0) {
+        error_setg_errno(errp, errno, "Failed to create socket");
+        return -1;
+    }
+
+    if (bind(slisten, (const struct sockaddr *)&svm, sizeof(svm)) != 0) {
+        error_setg_errno(errp, errno, "Failed to bind socket");
+        closesocket(slisten);
+        return -1;
+    }
+
+    if (listen(slisten, num) != 0) {
+        error_setg_errno(errp, errno, "Failed to listen on socket");
+        closesocket(slisten);
+        return -1;
+    }
+    return slisten;
+}
+
+static int vsock_parse(VsockSocketAddress *addr, const char *str,
+                       Error **errp)
+{
+    char cid[33];
+    char port[33];
+    int n;
+
+    if (sscanf(str, "%32[^:]:%32[^,]%n", cid, port, &n) != 2) {
+        error_setg(errp, "error parsing address '%s'", str);
+        return -1;
+    }
+    if (str[n] != '\0') {
+        error_setg(errp, "trailing characters in address '%s'", str);
+        return -1;
+    }
+
+    addr->cid = g_strdup(cid);
+    addr->port = g_strdup(port);
+    return 0;
+}
+#else
+static void vsock_unsupported(Error **errp)
+{
+    error_setg(errp, "socket family AF_VSOCK unsupported");
+}
+
+static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp)
+{
+    vsock_unsupported(errp);
+    return -1;
+}
+
+static int vsock_listen_saddr(VsockSocketAddress *vaddr,
+                              int num,
+                              Error **errp)
+{
+    vsock_unsupported(errp);
+    return -1;
+}
+
+static int vsock_parse(VsockSocketAddress *addr, const char *str,
+                        Error **errp)
+{
+    vsock_unsupported(errp);
+    return -1;
+}
+#endif /* CONFIG_AF_VSOCK */
+
+#ifndef _WIN32
+
+static bool saddr_is_abstract(UnixSocketAddress *saddr)
+{
+#ifdef CONFIG_LINUX
+    return saddr->abstract;
+#else
+    return false;
+#endif
+}
+
+static bool saddr_is_tight(UnixSocketAddress *saddr)
+{
+#ifdef CONFIG_LINUX
+    return !saddr->has_tight || saddr->tight;
+#else
+    return false;
+#endif
+}
+
+static int unix_listen_saddr(UnixSocketAddress *saddr,
+                             int num,
+                             Error **errp)
+{
+    bool abstract = saddr_is_abstract(saddr);
+    struct sockaddr_un un;
+    int sock, fd;
+    char *pathbuf = NULL;
+    const char *path;
+    size_t pathlen;
+    size_t addrlen;
+
+    sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
+    if (sock < 0) {
+        error_setg_errno(errp, errno, "Failed to create Unix socket");
+        return -1;
+    }
+
+    if (saddr->path[0] || abstract) {
+        path = saddr->path;
+    } else {
+        const char *tmpdir = getenv("TMPDIR");
+        tmpdir = tmpdir ? tmpdir : "/tmp";
+        path = pathbuf = g_strdup_printf("%s/qemu-socket-XXXXXX", tmpdir);
+    }
+
+    pathlen = strlen(path);
+    if (pathlen > sizeof(un.sun_path) ||
+        (abstract && pathlen > (sizeof(un.sun_path) - 1))) {
+        error_setg(errp, "UNIX socket path '%s' is too long", path);
+        error_append_hint(errp, "Path must be less than %zu bytes\n",
+                          abstract ? sizeof(un.sun_path) - 1 :
+                          sizeof(un.sun_path));
+        goto err;
+    }
+
+    if (pathbuf != NULL) {
+        /*
+         * This dummy fd usage silences the mktemp() unsecure warning.
+         * Using mkstemp() doesn't make things more secure here
+         * though.  bind() complains about existing files, so we have
+         * to unlink first and thus re-open the race window.  The
+         * worst case possible is bind() failing, i.e. a DoS attack.
+         */
+        fd = mkstemp(pathbuf);
+        if (fd < 0) {
+            error_setg_errno(errp, errno,
+                             "Failed to make a temporary socket %s", pathbuf);
+            goto err;
+        }
+        close(fd);
+    }
+
+    if (!abstract && unlink(path) < 0 && errno != ENOENT) {
+        error_setg_errno(errp, errno,
+                         "Failed to unlink socket %s", path);
+        goto err;
+    }
+
+    memset(&un, 0, sizeof(un));
+    un.sun_family = AF_UNIX;
+    addrlen = sizeof(un);
+
+    if (abstract) {
+        un.sun_path[0] = '\0';
+        memcpy(&un.sun_path[1], path, pathlen);
+        if (saddr_is_tight(saddr)) {
+            addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen;
+        }
+    } else {
+        memcpy(un.sun_path, path, pathlen);
+    }
+
+    if (bind(sock, (struct sockaddr *) &un, addrlen) < 0) {
+        error_setg_errno(errp, errno, "Failed to bind socket to %s", path);
+        goto err;
+    }
+    if (listen(sock, num) < 0) {
+        error_setg_errno(errp, errno, "Failed to listen on socket");
+        goto err;
+    }
+
+    g_free(pathbuf);
+    return sock;
+
+err:
+    g_free(pathbuf);
+    closesocket(sock);
+    return -1;
+}
+
+static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp)
+{
+    bool abstract = saddr_is_abstract(saddr);
+    struct sockaddr_un un;
+    int sock, rc;
+    size_t pathlen;
+    size_t addrlen;
+
+    if (saddr->path == NULL) {
+        error_setg(errp, "unix connect: no path specified");
+        return -1;
+    }
+
+    sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
+    if (sock < 0) {
+        error_setg_errno(errp, errno, "Failed to create socket");
+        return -1;
+    }
+
+    pathlen = strlen(saddr->path);
+    if (pathlen > sizeof(un.sun_path) ||
+        (abstract && pathlen > (sizeof(un.sun_path) - 1))) {
+        error_setg(errp, "UNIX socket path '%s' is too long", saddr->path);
+        error_append_hint(errp, "Path must be less than %zu bytes\n",
+                          abstract ? sizeof(un.sun_path) - 1 :
+                          sizeof(un.sun_path));
+        goto err;
+    }
+
+    memset(&un, 0, sizeof(un));
+    un.sun_family = AF_UNIX;
+    addrlen = sizeof(un);
+
+    if (abstract) {
+        un.sun_path[0] = '\0';
+        memcpy(&un.sun_path[1], saddr->path, pathlen);
+        if (saddr_is_tight(saddr)) {
+            addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen;
+        }
+    } else {
+        memcpy(un.sun_path, saddr->path, pathlen);
+    }
+    /* connect to peer */
+    do {
+        rc = 0;
+        if (connect(sock, (struct sockaddr *) &un, addrlen) < 0) {
+            rc = -errno;
+        }
+    } while (rc == -EINTR);
+
+    if (rc < 0) {
+        error_setg_errno(errp, -rc, "Failed to connect to '%s'",
+                         saddr->path);
+        goto err;
+    }
+
+    return sock;
+
+ err:
+    close(sock);
+    return -1;
+}
+
+#else
+
+static int unix_listen_saddr(UnixSocketAddress *saddr,
+                             int num,
+                             Error **errp)
+{
+    error_setg(errp, "unix sockets are not available on windows");
+    errno = ENOTSUP;
+    return -1;
+}
+
+static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp)
+{
+    error_setg(errp, "unix sockets are not available on windows");
+    errno = ENOTSUP;
+    return -1;
+}
+#endif
+
+/* compatibility wrapper */
+int unix_listen(const char *str, Error **errp)
+{
+    UnixSocketAddress *saddr;
+    int sock;
+
+    saddr = g_new0(UnixSocketAddress, 1);
+    saddr->path = g_strdup(str);
+    sock = unix_listen_saddr(saddr, 1, errp);
+    qapi_free_UnixSocketAddress(saddr);
+    return sock;
+}
+
+int unix_connect(const char *path, Error **errp)
+{
+    UnixSocketAddress *saddr;
+    int sock;
+
+    saddr = g_new0(UnixSocketAddress, 1);
+    saddr->path = g_strdup(path);
+    sock = unix_connect_saddr(saddr, errp);
+    qapi_free_UnixSocketAddress(saddr);
+    return sock;
+}
+
+
+SocketAddress *socket_parse(const char *str, Error **errp)
+{
+    SocketAddress *addr;
+
+    addr = g_new0(SocketAddress, 1);
+    if (strstart(str, "unix:", NULL)) {
+        if (str[5] == '\0') {
+            error_setg(errp, "invalid Unix socket address");
+            goto fail;
+        } else {
+            addr->type = SOCKET_ADDRESS_TYPE_UNIX;
+            addr->u.q_unix.path = g_strdup(str + 5);
+        }
+    } else if (strstart(str, "fd:", NULL)) {
+        if (str[3] == '\0') {
+            error_setg(errp, "invalid file descriptor address");
+            goto fail;
+        } else {
+            addr->type = SOCKET_ADDRESS_TYPE_FD;
+            addr->u.fd.str = g_strdup(str + 3);
+        }
+    } else if (strstart(str, "vsock:", NULL)) {
+        addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
+        if (vsock_parse(&addr->u.vsock, str + strlen("vsock:"), errp)) {
+            goto fail;
+        }
+    } else {
+        addr->type = SOCKET_ADDRESS_TYPE_INET;
+        if (inet_parse(&addr->u.inet, str, errp)) {
+            goto fail;
+        }
+    }
+    return addr;
+
+fail:
+    qapi_free_SocketAddress(addr);
+    return NULL;
+}
+
+static int socket_get_fd(const char *fdstr, Error **errp)
+{
+    Monitor *cur_mon = monitor_cur();
+    int fd;
+    if (cur_mon) {
+        fd = monitor_get_fd(cur_mon, fdstr, errp);
+        if (fd < 0) {
+            return -1;
+        }
+    } else {
+        if (qemu_strtoi(fdstr, NULL, 10, &fd) < 0) {
+            error_setg_errno(errp, errno,
+                             "Unable to parse FD number %s",
+                             fdstr);
+            return -1;
+        }
+    }
+    if (!fd_is_socket(fd)) {
+        error_setg(errp, "File descriptor '%s' is not a socket", fdstr);
+        close(fd);
+        return -1;
+    }
+    return fd;
+}
+
+int socket_address_parse_named_fd(SocketAddress *addr, Error **errp)
+{
+    int fd;
+
+    if (addr->type != SOCKET_ADDRESS_TYPE_FD) {
+        return 0;
+    }
+
+    fd = socket_get_fd(addr->u.fd.str, errp);
+    if (fd < 0) {
+        return fd;
+    }
+
+    g_free(addr->u.fd.str);
+    addr->u.fd.str = g_strdup_printf("%d", fd);
+
+    return 0;
+}
+
+int socket_connect(SocketAddress *addr, Error **errp)
+{
+    int fd;
+
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        fd = inet_connect_saddr(&addr->u.inet, errp);
+        break;
+
+    case SOCKET_ADDRESS_TYPE_UNIX:
+        fd = unix_connect_saddr(&addr->u.q_unix, errp);
+        break;
+
+    case SOCKET_ADDRESS_TYPE_FD:
+        fd = socket_get_fd(addr->u.fd.str, errp);
+        break;
+
+    case SOCKET_ADDRESS_TYPE_VSOCK:
+        fd = vsock_connect_saddr(&addr->u.vsock, errp);
+        break;
+
+    default:
+        abort();
+    }
+    return fd;
+}
+
+int socket_listen(SocketAddress *addr, int num, Error **errp)
+{
+    int fd;
+
+    trace_socket_listen(num);
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        fd = inet_listen_saddr(&addr->u.inet, 0, num, errp);
+        break;
+
+    case SOCKET_ADDRESS_TYPE_UNIX:
+        fd = unix_listen_saddr(&addr->u.q_unix, num, errp);
+        break;
+
+    case SOCKET_ADDRESS_TYPE_FD:
+        fd = socket_get_fd(addr->u.fd.str, errp);
+        if (fd < 0) {
+            return -1;
+        }
+
+        /*
+         * If the socket is not yet in the listen state, then transition it to
+         * the listen state now.
+         *
+         * If it's already listening then this updates the backlog value as
+         * requested.
+         *
+         * If this socket cannot listen because it's already in another state
+         * (e.g. unbound or connected) then we'll catch the error here.
+         */
+        if (listen(fd, num) != 0) {
+            error_setg_errno(errp, errno, "Failed to listen on fd socket");
+            closesocket(fd);
+            return -1;
+        }
+        break;
+
+    case SOCKET_ADDRESS_TYPE_VSOCK:
+        fd = vsock_listen_saddr(&addr->u.vsock, num, errp);
+        break;
+
+    default:
+        abort();
+    }
+    return fd;
+}
+
+void socket_listen_cleanup(int fd, Error **errp)
+{
+    SocketAddress *addr;
+
+    addr = socket_local_address(fd, errp);
+    if (!addr) {
+        return;
+    }
+
+    if (addr->type == SOCKET_ADDRESS_TYPE_UNIX
+        && addr->u.q_unix.path) {
+        if (unlink(addr->u.q_unix.path) < 0 && errno != ENOENT) {
+            error_setg_errno(errp, errno,
+                             "Failed to unlink socket %s",
+                             addr->u.q_unix.path);
+        }
+    }
+
+    qapi_free_SocketAddress(addr);
+}
+
+int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp)
+{
+    int fd;
+
+    /*
+     * TODO SOCKET_ADDRESS_TYPE_FD when fd is AF_INET or AF_INET6
+     * (although other address families can do SOCK_DGRAM, too)
+     */
+    switch (remote->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        fd = inet_dgram_saddr(&remote->u.inet,
+                              local ? &local->u.inet : NULL, errp);
+        break;
+
+    default:
+        error_setg(errp, "socket type unsupported for datagram");
+        fd = -1;
+    }
+    return fd;
+}
+
+
+static SocketAddress *
+socket_sockaddr_to_address_inet(struct sockaddr_storage *sa,
+                                socklen_t salen,
+                                Error **errp)
+{
+    char host[NI_MAXHOST];
+    char serv[NI_MAXSERV];
+    SocketAddress *addr;
+    InetSocketAddress *inet;
+    int ret;
+
+    ret = getnameinfo((struct sockaddr *)sa, salen,
+                      host, sizeof(host),
+                      serv, sizeof(serv),
+                      NI_NUMERICHOST | NI_NUMERICSERV);
+    if (ret != 0) {
+        error_setg(errp, "Cannot format numeric socket address: %s",
+                   gai_strerror(ret));
+        return NULL;
+    }
+
+    addr = g_new0(SocketAddress, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_INET;
+    inet = &addr->u.inet;
+    inet->host = g_strdup(host);
+    inet->port = g_strdup(serv);
+    if (sa->ss_family == AF_INET) {
+        inet->has_ipv4 = inet->ipv4 = true;
+    } else {
+        inet->has_ipv6 = inet->ipv6 = true;
+    }
+
+    return addr;
+}
+
+
+#ifndef WIN32
+static SocketAddress *
+socket_sockaddr_to_address_unix(struct sockaddr_storage *sa,
+                                socklen_t salen,
+                                Error **errp)
+{
+    SocketAddress *addr;
+    struct sockaddr_un *su = (struct sockaddr_un *)sa;
+
+    addr = g_new0(SocketAddress, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
+    salen -= offsetof(struct sockaddr_un, sun_path);
+#ifdef CONFIG_LINUX
+    if (salen > 0 && !su->sun_path[0]) {
+        /* Linux abstract socket */
+        addr->u.q_unix.path = g_strndup(su->sun_path + 1, salen - 1);
+        addr->u.q_unix.has_abstract = true;
+        addr->u.q_unix.abstract = true;
+        addr->u.q_unix.has_tight = true;
+        addr->u.q_unix.tight = salen < sizeof(su->sun_path);
+        return addr;
+    }
+#endif
+
+    addr->u.q_unix.path = g_strndup(su->sun_path, salen);
+    return addr;
+}
+#endif /* WIN32 */
+
+#ifdef CONFIG_AF_VSOCK
+static SocketAddress *
+socket_sockaddr_to_address_vsock(struct sockaddr_storage *sa,
+                                 socklen_t salen,
+                                 Error **errp)
+{
+    SocketAddress *addr;
+    VsockSocketAddress *vaddr;
+    struct sockaddr_vm *svm = (struct sockaddr_vm *)sa;
+
+    addr = g_new0(SocketAddress, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
+    vaddr = &addr->u.vsock;
+    vaddr->cid = g_strdup_printf("%u", svm->svm_cid);
+    vaddr->port = g_strdup_printf("%u", svm->svm_port);
+
+    return addr;
+}
+#endif /* CONFIG_AF_VSOCK */
+
+SocketAddress *
+socket_sockaddr_to_address(struct sockaddr_storage *sa,
+                           socklen_t salen,
+                           Error **errp)
+{
+    switch (sa->ss_family) {
+    case AF_INET:
+    case AF_INET6:
+        return socket_sockaddr_to_address_inet(sa, salen, errp);
+
+#ifndef WIN32
+    case AF_UNIX:
+        return socket_sockaddr_to_address_unix(sa, salen, errp);
+#endif /* WIN32 */
+
+#ifdef CONFIG_AF_VSOCK
+    case AF_VSOCK:
+        return socket_sockaddr_to_address_vsock(sa, salen, errp);
+#endif
+
+    default:
+        error_setg(errp, "socket family %d unsupported",
+                   sa->ss_family);
+        return NULL;
+    }
+    return 0;
+}
+
+
+SocketAddress *socket_local_address(int fd, Error **errp)
+{
+    struct sockaddr_storage ss;
+    socklen_t sslen = sizeof(ss);
+
+    if (getsockname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
+        error_setg_errno(errp, errno, "%s",
+                         "Unable to query local socket address");
+        return NULL;
+    }
+
+    return socket_sockaddr_to_address(&ss, sslen, errp);
+}
+
+
+SocketAddress *socket_remote_address(int fd, Error **errp)
+{
+    struct sockaddr_storage ss;
+    socklen_t sslen = sizeof(ss);
+
+    if (getpeername(fd, (struct sockaddr *)&ss, &sslen) < 0) {
+        error_setg_errno(errp, errno, "%s",
+                         "Unable to query remote socket address");
+        return NULL;
+    }
+
+    return socket_sockaddr_to_address(&ss, sslen, errp);
+}
+
+
+SocketAddress *socket_address_flatten(SocketAddressLegacy *addr_legacy)
+{
+    SocketAddress *addr;
+
+    if (!addr_legacy) {
+        return NULL;
+    }
+
+    addr = g_new(SocketAddress, 1);
+
+    switch (addr_legacy->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        addr->type = SOCKET_ADDRESS_TYPE_INET;
+        QAPI_CLONE_MEMBERS(InetSocketAddress, &addr->u.inet,
+                           addr_legacy->u.inet.data);
+        break;
+    case SOCKET_ADDRESS_TYPE_UNIX:
+        addr->type = SOCKET_ADDRESS_TYPE_UNIX;
+        QAPI_CLONE_MEMBERS(UnixSocketAddress, &addr->u.q_unix,
+                           addr_legacy->u.q_unix.data);
+        break;
+    case SOCKET_ADDRESS_TYPE_VSOCK:
+        addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
+        QAPI_CLONE_MEMBERS(VsockSocketAddress, &addr->u.vsock,
+                           addr_legacy->u.vsock.data);
+        break;
+    case SOCKET_ADDRESS_TYPE_FD:
+        addr->type = SOCKET_ADDRESS_TYPE_FD;
+        QAPI_CLONE_MEMBERS(String, &addr->u.fd, addr_legacy->u.fd.data);
+        break;
+    default:
+        abort();
+    }
+
+    return addr;
+}