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Re: [Qemu-devel] [PATCH v2 3/4] sockets: add AF_VSOCK support


From: Michael Roth
Subject: Re: [Qemu-devel] [PATCH v2 3/4] sockets: add AF_VSOCK support
Date: Tue, 25 Oct 2016 18:51:19 -0500
User-agent: alot/0.3.6

Quoting Stefan Hajnoczi (2016-10-14 04:00:55)
> Add the AF_VSOCK address family so that qemu-ga will be able to use
> virtio-vsock.
> 
> The AF_VSOCK address family uses <cid, port> address tuples.  The cid is
> the unique identifier comparable to an IP address.  AF_VSOCK does not
> use name resolution so it's easy to convert between struct sockaddr_vm
> and strings.
> 
> This patch defines a VsockSocketAddress instead of trying to piggy-back
> on InetSocketAddress.  This is cleaner in the long run since it avoids
> lots of IPv4 vs IPv6 vs vsock special casing.
> 
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> v2:
>  * s/seasy/easy/ typo fix in commit description [Eric]
>  * Use %n to check for trailing characters in addresses [Eric]
> ---
>  qapi-schema.json    |  23 +++++-
>  util/qemu-sockets.c | 227 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 249 insertions(+), 1 deletion(-)
> 
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 9e47b47..12aea99 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -988,12 +988,14 @@
>  #
>  # @unix: unix socket
>  #
> +# @vsock: vsock family (since 2.8)
> +#
>  # @unknown: otherwise
>  #
>  # Since: 2.1
>  ##
>  { 'enum': 'NetworkAddressFamily',
> -  'data': [ 'ipv4', 'ipv6', 'unix', 'unknown' ] }
> +  'data': [ 'ipv4', 'ipv6', 'unix', 'vsock', 'unknown' ] }
> 
>  ##
>  # @VncBasicInfo
> @@ -3018,6 +3020,24 @@
>      'path': 'str' } }
> 
>  ##
> +# @VsockSocketAddress
> +#
> +# Captures a socket address in the vsock namespace.
> +#
> +# @cid: unique host identifier
> +# @port: port
> +#
> +# Note that string types are used to allow for possible future hostname or
> +# service resolution support.
> +#
> +# Since 2.8
> +##
> +{ 'struct': 'VsockSocketAddress',
> +  'data': {
> +    'cid': 'str',
> +    'port': 'str' } }
> +
> +##
>  # @SocketAddress
>  #
>  # Captures the address of a socket, which could also be a named file 
> descriptor
> @@ -3028,6 +3048,7 @@
>    'data': {
>      'inet': 'InetSocketAddress',
>      'unix': 'UnixSocketAddress',
> +    'vsock': 'VsockSocketAddress',
>      'fd': 'String' } }
> 
>  ##
> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
> index 6db48b3..6ef3cc5 100644
> --- a/util/qemu-sockets.c
> +++ b/util/qemu-sockets.c
> @@ -17,6 +17,10 @@
>   */
>  #include "qemu/osdep.h"
> 
> +#ifdef AF_VSOCK
> +#include <linux/vm_sockets.h>
> +#endif /* AF_VSOCK */

I have this series applied locally but I hit some build issues on Ubuntu
14.04 due to linux/vm_sockets.h not being provided by Ubuntu 14.04's
linux-libc-dev package. It is however included with linux-libc-dev in
16.04. linux-headers package includes it in both cases, but installs
to /usr/src/linux-headers*, which are not part of the default include
path.

Do you think we need a configure check and CONFIG_AF_VSOCK flag instead?

> +
>  #include "monitor/monitor.h"
>  #include "qapi/error.h"
>  #include "qemu/sockets.h"
> @@ -75,6 +79,9 @@ NetworkAddressFamily inet_netfamily(int 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 AF_VSOCK
> +    case PF_VSOCK: return NETWORK_ADDRESS_FAMILY_VSOCK;
> +#endif /* AF_VSOCK */
>      }
>      return NETWORK_ADDRESS_FAMILY_UNKNOWN;
>  }
> @@ -650,6 +657,181 @@ int inet_connect(const char *str, Error **errp)
>      return sock;
>  }
> 
> +#ifdef 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 struct sockaddr_vm *svm, bool 
> *in_progress,
> +                              ConnectState *connect_state, Error **errp)
> +{
> +    int sock, rc;
> +
> +    *in_progress = false;
> +
> +    sock = qemu_socket(AF_VSOCK, SOCK_STREAM, 0);
> +    if (sock < 0) {
> +        error_setg_errno(errp, errno, "Failed to create socket");
> +        return -1;
> +    }
> +    if (connect_state != NULL) {
> +        qemu_set_nonblock(sock);
> +    }
> +    /* connect to peer */
> +    do {
> +        rc = 0;
> +        if (connect(sock, (const struct sockaddr *)svm, sizeof(*svm)) < 0) {
> +            rc = -errno;
> +        }
> +    } while (rc == -EINTR);
> +
> +    if (connect_state != NULL && QEMU_SOCKET_RC_INPROGRESS(rc)) {
> +        connect_state->fd = sock;
> +        qemu_set_fd_handler(sock, NULL, wait_for_connect, connect_state);
> +        *in_progress = true;
> +    } else if (rc < 0) {
> +        error_setg_errno(errp, errno, "Failed to connect socket");
> +        closesocket(sock);
> +        return -1;
> +    }
> +    return sock;
> +}
> +
> +static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp,
> +                               NonBlockingConnectHandler *callback,
> +                               void *opaque)
> +{
> +    struct sockaddr_vm svm;
> +    int sock = -1;
> +    bool in_progress;
> +    ConnectState *connect_state = NULL;
> +
> +    if (!vsock_parse_vaddr_to_sockaddr(vaddr, &svm, errp)) {
> +        return -1;
> +    }
> +
> +    if (callback != NULL) {
> +        connect_state = g_malloc0(sizeof(*connect_state));
> +        connect_state->callback = callback;
> +        connect_state->opaque = opaque;
> +    }
> +
> +    sock = vsock_connect_addr(&svm, &in_progress, connect_state, errp);
> +    if (sock < 0) {
> +        /* do nothing */
> +    } else if (in_progress) {
> +        /* wait_for_connect() will do the rest */
> +        return sock;
> +    } else {
> +        if (callback) {
> +            callback(sock, NULL, opaque);
> +        }
> +    }
> +    g_free(connect_state);
> +    return sock;
> +}
> +
> +static int vsock_listen_saddr(VsockSocketAddress *vaddr,
> +                              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, 1) != 0) {
> +        error_setg_errno(errp, errno, "Failed to listen on socket");
> +        closesocket(slisten);
> +        return -1;
> +    }
> +    return slisten;
> +}
> +
> +static VsockSocketAddress *vsock_parse(const char *str, Error **errp)
> +{
> +    VsockSocketAddress *addr = NULL;
> +    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 NULL;
> +    }
> +    if (str[n] != '\0') {
> +        error_setg(errp, "trailing characters in address '%s'", str);
> +        return NULL;
> +    }
> +
> +    addr = g_new0(VsockSocketAddress, 1);
> +    addr->cid = g_strdup(cid);
> +    addr->port = g_strdup(port);
> +    return addr;
> +}
> +#else
> +static void vsock_unsupported(Error **errp)
> +{
> +    error_setg(errp, "socket family AF_VSOCK unsupported");
> +}
> +
> +static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp,
> +                               NonBlockingConnectHandler *callback,
> +                               void *opaque)
> +{
> +    vsock_unsupported(errp);
> +    return -1;
> +}
> +
> +static int vsock_listen_saddr(VsockSocketAddress *vaddr,
> +                              Error **errp)
> +{
> +    vsock_unsupported(errp);
> +    return -1;
> +}
> +
> +static VsockSocketAddress *vsock_parse(const char *str, Error **errp)
> +{
> +    vsock_unsupported(errp);
> +    return NULL;
> +}
> +#endif /* AF_VSOCK */
> +
>  #ifndef _WIN32
> 
>  static int unix_listen_saddr(UnixSocketAddress *saddr,
> @@ -864,6 +1046,12 @@ SocketAddress *socket_parse(const char *str, Error 
> **errp)
>              addr->u.fd.data = g_new(String, 1);
>              addr->u.fd.data->str = g_strdup(str + 3);
>          }
> +    } else if (strstart(str, "vsock:", NULL)) {
> +        addr->type = SOCKET_ADDRESS_KIND_VSOCK;
> +        addr->u.vsock.data = vsock_parse(str + strlen("vsock:"), errp);
> +        if (addr->u.vsock.data == NULL) {
> +            goto fail;
> +        }
>      } else {
>          addr->type = SOCKET_ADDRESS_KIND_INET;
>          addr->u.inet.data = inet_parse(str, errp);
> @@ -900,6 +1088,10 @@ int socket_connect(SocketAddress *addr, Error **errp,
>          }
>          break;
> 
> +    case SOCKET_ADDRESS_KIND_VSOCK:
> +        fd = vsock_connect_saddr(addr->u.vsock.data, errp, callback, opaque);
> +        break;
> +
>      default:
>          abort();
>      }
> @@ -923,6 +1115,10 @@ int socket_listen(SocketAddress *addr, Error **errp)
>          fd = monitor_get_fd(cur_mon, addr->u.fd.data->str, errp);
>          break;
> 
> +    case SOCKET_ADDRESS_KIND_VSOCK:
> +        fd = vsock_listen_saddr(addr->u.vsock.data, errp);
> +        break;
> +
>      default:
>          abort();
>      }
> @@ -1022,6 +1218,26 @@ socket_sockaddr_to_address_unix(struct 
> sockaddr_storage *sa,
>  }
>  #endif /* WIN32 */
> 
> +#ifdef 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_KIND_VSOCK;
> +    addr->u.vsock.data = vaddr = g_new0(VsockSocketAddress, 1);
> +    vaddr->cid = g_strdup_printf("%u", svm->svm_cid);
> +    vaddr->port = g_strdup_printf("%u", svm->svm_port);
> +
> +    return addr;
> +}
> +#endif /* AF_VSOCK */
> +
>  SocketAddress *
>  socket_sockaddr_to_address(struct sockaddr_storage *sa,
>                             socklen_t salen,
> @@ -1037,6 +1253,11 @@ socket_sockaddr_to_address(struct sockaddr_storage *sa,
>          return socket_sockaddr_to_address_unix(sa, salen, errp);
>  #endif /* WIN32 */
> 
> +#ifdef 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);
> @@ -1103,6 +1324,12 @@ char *socket_address_to_string(struct SocketAddress 
> *addr, Error **errp)
>          buf = g_strdup(addr->u.fd.data->str);
>          break;
> 
> +    case SOCKET_ADDRESS_KIND_VSOCK:
> +        buf = g_strdup_printf("%s:%s",
> +                              addr->u.vsock.data->cid,
> +                              addr->u.vsock.data->port);
> +        break;
> +
>      default:
>          error_setg(errp, "socket family %d unsupported",
>                     addr->type);
> -- 
> 2.7.4
> 




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