Re: [Qemu-devel] [PULL 2/4] net: L2TPv3 transport

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2014-06-27 16:24, Stefan Hajnoczi wrote:
> From: Anton Ivanov <antivano@cisco.com>
> 
> This transport allows to connect a QEMU nic to a static Ethernet
> over L2TPv3 tunnel. The transport supports all options present
> in the Linux kernel implementation. It allows QEMU to connect
> to any Linux host running kernel 3.3+, most routers and network
> devices as well as other QEMU instances.
> 
> [Fixed up net_client_init1() switch statement to support -netdev
> --Stefan]
> 
> Signed-off-by: Anton Ivanov <antivano@cisco.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  net/Makefile.objs |   1 +
>  net/clients.h     |   2 +
>  net/l2tpv3.c      | 757 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  net/net.c         |   6 +
>  qapi-schema.json  |  60 +++++
>  qemu-options.hx   |  82 ++++++
>  6 files changed, 908 insertions(+)
>  create mode 100644 net/l2tpv3.c
> 
> diff --git a/net/Makefile.objs b/net/Makefile.objs
> index 301f6b6..a06ba59 100644
> --- a/net/Makefile.objs
> +++ b/net/Makefile.objs
> @@ -2,6 +2,7 @@ common-obj-y = net.o queue.o checksum.o util.o hub.o
>  common-obj-y += socket.o
>  common-obj-y += dump.o
>  common-obj-y += eth.o
> +common-obj-$(CONFIG_LINUX) += l2tpv3.o
>  common-obj-$(CONFIG_POSIX) += tap.o vhost-user.o
>  common-obj-$(CONFIG_LINUX) += tap-linux.o
>  common-obj-$(CONFIG_WIN32) += tap-win32.o
> diff --git a/net/clients.h b/net/clients.h
> index 7f3d4ae..2e8feda 100644
> --- a/net/clients.h
> +++ b/net/clients.h
> @@ -47,6 +47,8 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
>  int net_init_bridge(const NetClientOptions *opts, const char *name,
>                      NetClientState *peer);
>  
> +int net_init_l2tpv3(const NetClientOptions *opts, const char *name,
> +                    NetClientState *peer);
>  #ifdef CONFIG_VDE
>  int net_init_vde(const NetClientOptions *opts, const char *name,
>                   NetClientState *peer);
> diff --git a/net/l2tpv3.c b/net/l2tpv3.c
> new file mode 100644
> index 0000000..528d95b
> --- /dev/null
> +++ b/net/l2tpv3.c
> @@ -0,0 +1,757 @@
> +/*
> + * QEMU System Emulator
> + *
> + * Copyright (c) 2003-2008 Fabrice Bellard
> + * Copyright (c) 2012-2014 Cisco Systems
> + *
> + * 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 <linux/ip.h>
> +#include <netdb.h>
> +#include "config-host.h"
> +#include "net/net.h"
> +#include "clients.h"
> +#include "monitor/monitor.h"
> +#include "qemu-common.h"
> +#include "qemu/error-report.h"
> +#include "qemu/option.h"
> +#include "qemu/sockets.h"
> +#include "qemu/iov.h"
> +#include "qemu/main-loop.h"
> +
> +
> +/* The buffer size needs to be investigated for optimum numbers and
> + * optimum means of paging in on different systems. This size is
> + * chosen to be sufficient to accommodate one packet with some headers
> + */
> +
> +#define BUFFER_ALIGN sysconf(_SC_PAGESIZE)
> +#define BUFFER_SIZE 2048
> +#define IOVSIZE 2
> +#define MAX_L2TPV3_MSGCNT 64
> +#define MAX_L2TPV3_IOVCNT (MAX_L2TPV3_MSGCNT * IOVSIZE)
> +
> +/* Header set to 0x30000 signifies a data packet */
> +
> +#define L2TPV3_DATA_PACKET 0x30000
> +
> +/* IANA-assigned IP protocol ID for L2TPv3 */
> +
> +#ifndef IPPROTO_L2TP
> +#define IPPROTO_L2TP 0x73
> +#endif
> +
> +typedef struct NetL2TPV3State {
> +    NetClientState nc;
> +    int fd;
> +
> +    /*
> +     * these are used for xmit - that happens packet a time
> +     * and for first sign of life packet (easier to parse that once)
> +     */
> +
> +    uint8_t *header_buf;
> +    struct iovec *vec;
> +
> +    /*
> +     * these are used for receive - try to "eat" up to 32 packets at a time
> +     */
> +
> +    struct mmsghdr *msgvec;

struct mmsghdr is only available with recent distro kernel headers.
Please check if it's there and otherwise disable L2TPv3 (or provide the
struct yourself).

Thanks,
Jan

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