Re: [Qemu-devel] [PATCH 3/3] Unified Datagram Socket Transport - raw support

[Anton Ivanov]

I tried tpacket long ago when I started working on this. It was slower as there 
was no way to turn off timestamps on the packet ring. They are quite expensive. 

I have not looked at it lately. It will be interesting to compare.

On 19 July 2017 07:58:48 CEST, Jason Wang <address@hidden> wrote:
>
>
>On 2017年07月19日 01:08, address@hidden wrote:
>> From: Anton Ivanov <address@hidden>
>>
>> This adds raw socket support to the unified socket driver.
>
>Interesting, in fact, I've finished a tpacket backend. Let me post it 
>sometime after hardfreeze.
>
>> Signed-off-by: Anton Ivanov <address@hidden>
>> ---
>>   net/Makefile.objs |   2 +-
>>   net/clients.h     |   3 ++
>>   net/net.c         |   5 +++
>>   net/raw.c         | 123
>++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   qapi-schema.json  |  25 +++++++++--
>>   qemu-options.hx   |  33 +++++++++++++++
>>   6 files changed, 186 insertions(+), 5 deletions(-)
>>   create mode 100644 net/raw.c
>>
>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>> index 128164e39b..54cf7dd194 100644
>> --- a/net/Makefile.objs
>> +++ b/net/Makefile.objs
>> @@ -2,7 +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-$(CONFIG_UNIFIED) += l2tpv3.o unified.o gre.o
>> +common-obj-$(CONFIG_UNIFIED) += l2tpv3.o unified.o gre.o raw.o
>>   common-obj-$(CONFIG_POSIX) += vhost-user.o
>>   common-obj-$(CONFIG_SLIRP) += slirp.o
>>   common-obj-$(CONFIG_VDE) += vde.o
>> diff --git a/net/clients.h b/net/clients.h
>> index 8f8a59aee3..98d8ae59b7 100644
>> --- a/net/clients.h
>> +++ b/net/clients.h
>> @@ -53,6 +53,9 @@ int net_init_l2tpv3(const Netdev *netdev, const
>char *name,
>>   int net_init_gre(const Netdev *netdev, const char *name,
>>                       NetClientState *peer, Error **errp);
>>   
>> +int net_init_raw(const Netdev *netdev, const char *name,
>> +                    NetClientState *peer, Error **errp);
>> +
>>   #ifdef CONFIG_VDE
>>   int net_init_vde(const Netdev *netdev, const char *name,
>>                    NetClientState *peer, Error **errp);
>> diff --git a/net/net.c b/net/net.c
>> index b75b6e8154..2d988a120c 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -962,6 +962,7 @@ static int (* const
>net_client_init_fun[NET_CLIENT_DRIVER__MAX])(
>>   #ifdef CONFIG_UNIFIED
>>           [NET_CLIENT_DRIVER_L2TPV3] = net_init_l2tpv3,
>>           [NET_CLIENT_DRIVER_GRE] = net_init_gre,
>> +        [NET_CLIENT_DRIVER_RAW] = net_init_raw,
>>   #endif
>>   };
>>   
>> @@ -1017,6 +1018,10 @@ static int net_client_init1(const void
>*object, bool is_netdev, Error **errp)
>>               legacy.type = NET_CLIENT_DRIVER_GRE;
>>               legacy.u.gre = opts->u.gre;
>>               break;
>> +        case NET_LEGACY_OPTIONS_TYPE_RAW:
>> +            legacy.type = NET_CLIENT_DRIVER_RAW;
>> +            legacy.u.raw = opts->u.raw;
>> +            break;
>>           case NET_LEGACY_OPTIONS_TYPE_SOCKET:
>>               legacy.type = NET_CLIENT_DRIVER_SOCKET;
>>               legacy.u.socket = opts->u.socket;
>> diff --git a/net/raw.c b/net/raw.c
>> new file mode 100644
>> index 0000000000..73e2fd9fe3
>> --- /dev/null
>> +++ b/net/raw.c
>> @@ -0,0 +1,123 @@
>> +/*
>> + * QEMU System Emulator
>> + *
>> + * Copyright (c) 2015-2017 Cambridge Greys Limited
>> + * 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 "qemu/osdep.h"
>> +#include <linux/ip.h>
>> +#include <netdb.h>
>> +#include <sys/ioctl.h>
>> +#include <net/if.h>
>> +#include "net/net.h"
>> + #include <sys/socket.h>
>> +#include <linux/if_packet.h>
>> +#include <net/ethernet.h>
>> +#include "clients.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"
>> +#include "unified.h"
>> +
>> +static int noop(void *us, uint8_t *buf)
>> +{
>> +    return 0;
>> +}
>> +
>> +int net_init_raw(const Netdev *netdev,
>> +                    const char *name,
>> +                    NetClientState *peer, Error **errp)
>> +{
>> +
>> +    const NetdevRawOptions *raw;
>> +    NetUnifiedState *s;
>> +    NetClientState *nc;
>> +
>> +    int fd = -1;
>> +    int err;
>> +
>> +    struct ifreq ifr;
>> +    struct sockaddr_ll sock;
>> +
>> +
>> +    nc = qemu_new_unified_net_client(name, peer);
>> +
>> +    s = DO_UPCAST(NetUnifiedState, nc, nc);
>> +
>> +    fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
>> +    if (fd == -1) {
>> +        err = -errno;
>> +        error_report("raw_open : raw socket creation failed, errno =
>%d", -err);
>> +        goto outerr;
>> +    }
>> +
>> +
>> +    s->form_header = NULL;
>> +    s->verify_header = &noop;
>> +    s->queue_head = 0;
>> +    s->queue_tail = 0;
>> +    s->header_mismatch = false;
>> +    s->dgram_dst = NULL;
>> +    s->dst_size = 0;
>> +
>> +    assert(netdev->type == NET_CLIENT_DRIVER_RAW);
>> +    raw = &netdev->u.raw;
>> +
>> +    memset(&ifr, 0, sizeof(struct ifreq));
>> +    strncpy((char *) &ifr.ifr_name, raw->ifname,
>sizeof(ifr.ifr_name) - 1);
>> +
>> +    if (ioctl(fd, SIOCGIFINDEX, (void *) &ifr) < 0) {
>> +        err = -errno;
>> +        error_report("SIOCGIFINDEX, failed to get raw interface
>index for %s",
>> +            raw->ifname);
>> +        goto outerr;
>> +    }
>> +
>> +    sock.sll_family = AF_PACKET;
>> +    sock.sll_protocol = htons(ETH_P_ALL);
>> +    sock.sll_ifindex = ifr.ifr_ifindex;
>> +
>> +    if (bind(fd, (struct sockaddr *) &sock, sizeof(struct
>sockaddr_ll)) < 0) {
>> +        error_report("raw: failed to bind raw socket");
>> +        err = -errno;
>> +        goto outerr;
>> +    }
>> +
>> +    s->offset = 0;
>> +
>> +    qemu_net_finalize_unified_init(s, fd);
>> +
>> +    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
>> +             "raw: connected");
>> +    return 0;
>> +outerr:
>> +    qemu_del_net_client(nc);
>> +    if (fd >= 0) {
>> +        close(fd);
>> +    }
>> +    return -1;
>> +}
>> +
>> diff --git a/qapi-schema.json b/qapi-schema.json
>> index aec303a14e..cde78ce3a1 100644
>> --- a/qapi-schema.json
>> +++ b/qapi-schema.json
>> @@ -3883,6 +3883,21 @@
>>       '*txkey':    'uint32',
>>       '*rxkey':    'uint32' } }
>>   ##
>> +# @NetdevRawOptions:
>> +#
>> +# Connect the VLAN to an network interface using raw sockets
>> +#
>> +# @ifname: network interface name
>> +#
>> +
>> +# Since 2.9
>
>2.11.
>
>> +##
>> +{ 'struct': 'NetdevRawOptions',
>> +  'data': {
>> +    'ifname':          'str'
>> +} }
>> +
>> +##
>>   # @NetdevVdeOptions:
>>   #
>>   # Connect the VLAN to a vde switch running on the host.
>> @@ -4000,7 +4015,7 @@
>>   ##
>>   { 'enum': 'NetClientDriver',
>>     'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket',
>'vde', 'dump',
>> -            'bridge', 'hubport', 'netmap', 'vhost-user', 'gre' ] }
>> +            'bridge', 'hubport', 'netmap', 'vhost-user', 'gre',
>'raw' ] }
>>   
>>   ##
>>   # @Netdev:
>> @@ -4031,7 +4046,8 @@
>>       'hubport':  'NetdevHubPortOptions',
>>       'netmap':   'NetdevNetmapOptions',
>>       'vhost-user': 'NetdevVhostUserOptions',
>> -    'gre':      'NetdevGREOptions' } }
>> +    'gre':      'NetdevGREOptions',
>> +    'raw':      'NetdevRawOptions' } }
>>   
>>   ##
>>   # @NetLegacy:
>> @@ -4062,7 +4078,7 @@
>>   ##
>>   { 'enum': 'NetLegacyOptionsType',
>>     'data': ['none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
>> -           'dump', 'bridge', 'netmap', 'vhost-user', 'gre'] }
>> +           'dump', 'bridge', 'netmap', 'vhost-user', 'gre', 'raw'] }
>>   
>>   ##
>>   # @NetLegacyOptions:
>> @@ -4086,7 +4102,8 @@
>>       'bridge':   'NetdevBridgeOptions',
>>       'netmap':   'NetdevNetmapOptions',
>>       'vhost-user': 'NetdevVhostUserOptions',
>> -    'gre':      'NetdevGREOptions' } }
>> +    'gre':      'NetdevGREOptions',
>> +    'raw':      'NetdevRawOptions' } }
>>   
>>   ##
>>   # @NetFilterDirection:
>> diff --git a/qemu-options.hx b/qemu-options.hx
>> index 6f8d5cbe21..d9db8b576b 100644
>> --- a/qemu-options.hx
>> +++ b/qemu-options.hx
>> @@ -1988,6 +1988,13 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
>>       "                use 'txkey=0x01234' to specify a txkey\n"
>>       "                use 'sequence=on' to add frame sequence to
>each packet\n"
>>       "                use 'pinsequence=on' to work around broken
>sequence handling in peer\n"
>> +    "-netdev raw,id=str,ifname=ifname\n"
>> +    "                configure a network backend with ID 'str'
>connected to\n"
>> +    "                an Ethernet interface named ifname via raw
>socket.\n"
>> +    "                This backend does not change the interface
>settings.\n"
>> +    "                Most interfaces will require being set into
>promisc mode,\n"
>> +    "                as well having most offloads (TSO, etc) turned
>off.\n"
>> +    "                Some virtual interfaces like tap support only
>RX.\n"
>
>Pay attention that qemu supports vnet header. So any reason to turn off
>
>e.g TSO here?
>
>>   #endif
>>       "-netdev
>socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
>>       "                configure a network backend to connect to
>another network\n"
>> @@ -2463,6 +2470,32 @@ qemu-system-i386 linux.img -net nic -net
>gre,src=4.2.3.1,dst=1.2.3.4
>>   
>>   @end example
>>   
>> address@hidden -netdev raw,address@hidden,address@hidden
>> address@hidden -net raw[,address@hidden,address@hidden,address@hidden
>> +Connect VLAN @var{n} directly to an Ethernet interface using raw
>socket.
>> +
>> +This transport allows a VM to bypass most of the network stack which
>is
>> +extremely useful for tapping.
>> +
>> address@hidden address@hidden
>> +    interface name (mandatory)
>> +
>> address@hidden
>> +# set up the interface - put it in promiscuous mode and turn off
>offloads
>> +ifconfig eth0 up
>> +ifconfig eth0 promisc
>> +
>> +/sbin/ethtool -K eth0 gro off
>> +/sbin/ethtool -K eth0 tso off
>> +/sbin/ethtool -K eth0 gso off
>> +/sbin/ethtool -K eth0 tx off
>
>Any reason to turn off tx here?
>
>> +
>> +# launch QEMU instance - if your network has reorder or is very
>lossy add ,pincounter
>> +
>> +qemu-system-i386 linux.img -net nic -net raw,ifname=eth0
>
>Can we switch to use -netdev here?
>
>Thanks
>
>> +
>> address@hidden example
>> +
>>   @item -netdev
>vde,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden
>>   @itemx -net
>vde[,address@hidden,address@hidden,address@hidden
>[,address@hidden,address@hidden,address@hidden
>>   Connect VLAN @var{n} to PORT @var{n} of a vde switch running on
>host and

-- 
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