[ovs-dev] [PATCH v2] dpif-netlink: convert packet_type netlink attribute

Eric Garver e at erig.me
Thu Jul 6 12:54:16 UTC 2017


On Thu, Jul 06, 2017 at 10:14:06AM +0000, Yang, Yi Y wrote:
> I misunderstood Eric, he means we shouldn't have ETHERTYPE if packet_type is L3 type. I tried this one just now, it works.

No. That's not what I meant. We _need_ ETHERTYPE for L3-type (NS 1). The
kernel expects this since it does not understand packet_type.

See my additional comments below.

> 
> diff --git a/lib/odp-util.c b/lib/odp-util.c
> index 20373ec..2bf30bb 100644
> --- a/lib/odp-util.c
> +++ b/lib/odp-util.c
> @@ -4883,7 +4883,9 @@ odp_flow_key_from_flow__(const struct odp_flow_key_parms *parms,
>          goto unencap;
>      }
> 
> -    nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, data->dl_type);
> +    if (flow->packet_type == htonl(PT_ETH)) {
> +        nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, data->dl_type);
> +    }
> 
>      if (eth_type_vlan(flow->dl_type)) {
>          goto unencap;
> 
> -----Original Message-----
> From: Zoltán Balogh [mailto:zoltan.balogh at ericsson.com] 
> Sent: Thursday, July 6, 2017 6:12 PM
> To: Yang, Yi Y <yi.y.yang at intel.com>; Eric Garver <e at erig.me>
> Cc: 'dev at openvswitch.org' <dev at openvswitch.org>; Jan Scheurich <jan.scheurich at ericsson.com>
> Subject: RE: [ovs-dev] [PATCH v2] dpif-netlink: convert packet_type netlink attribute
> 
> Hello Yi,
> 
> I ran make check after applying your change and two tunnel tests did fail.
> 
> ## ------------------------------ ##
> ## openvswitch 2.7.90 test suite. ##
> ## ------------------------------ ##
> 
> 790: tunnel_push_pop_ipv6 - action                   FAILED (tunnel-push-pop-ipv6.at:170)
> 787: tunnel_push_pop - action                        FAILED (tunnel-push-pop.at:221)
> 
> The error message from testsuite.log:
> +2017-07-06T10:06:32.119Z|00001|odp_util(revalidator37)|ERR|attribute 
> +eth has length 2 but should have length 12
> 
> Best regards,
> Zoltan
> 
> > -----Original Message-----
> > From: Yang, Yi Y [mailto:yi.y.yang at intel.com]
> > Sent: Thursday, July 06, 2017 11:10 AM
> > To: Eric Garver <e at erig.me>; Zoltán Balogh 
> > <zoltan.balogh at ericsson.com>
> > Cc: 'dev at openvswitch.org' <dev at openvswitch.org>
> > Subject: RE: [ovs-dev] [PATCH v2] dpif-netlink: convert packet_type 
> > netlink attribute
> > 
> > Eric, maybe the below patch can fix your issue, please give a try.
> > 
> > diff --git a/lib/odp-util.c b/lib/odp-util.c index 20373ec..c5f714d 
> > 100644
> > --- a/lib/odp-util.c
> > +++ b/lib/odp-util.c
> > @@ -4863,6 +4863,9 @@ odp_flow_key_from_flow__(const struct odp_flow_key_parms *parms,
> >                  goto unencap;
> >              }
> >          }
> > +    } else {
> > +        if (export_mask) {
> > +            nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, 
> > + OVS_BE16_MAX);
> >      }
> > 
> >      if (ntohs(flow->dl_type) < ETH_TYPE_MIN) {
> > 
> > -----Original Message-----
> > From: Eric Garver [mailto:e at erig.me]
> > Sent: Wednesday, July 5, 2017 11:14 PM
> > To: Zoltán Balogh <zoltan.balogh at ericsson.com>
> > Cc: Yang, Yi Y <yi.y.yang at intel.com>; 'dev at openvswitch.org' 
> > <dev at openvswitch.org>
> > Subject: Re: [ovs-dev] [PATCH v2] dpif-netlink: convert packet_type 
> > netlink attribute
> > 
> > Hi Zoltan,
> > 
> > On Tue, Jul 04, 2017 at 09:23:17PM +0000, Zoltán Balogh wrote:
> > > By introducing packet type-aware pipeline, match on ethertype was 
> > > removed when packet type is not Ethernet. As pointed out by Eric 
> > > Garver, this could have a side effect on the kernel datapath:
> > > https://patchwork.ozlabs.org/patch/782991/
> > >
> > > This patch does approach the problem from a different perspective.
> > > Instead of re-introducing the unconditional match on Ethernet type 
> > > in all megaflow entries, as suggested by Eric, mapping of 
> > > packet_type != PT_ETH to dl_type could be handled in the put_exclude_packet_type() in dpif-netlink.c.
> > >
> > > Put_exclude_packet_type() filters the packet_type netlink attribute 
> > > out, before all attributes are sent from userspace to kernel. This 
> > > commit modifies the put_exclude_packet_type() function to do a 
> > > proper conversation and add the missing OVS_KEY_ATTR_ETHERTYPE attribute if it's needed.
> > >
> > > Signed-off-by: Zoltán Balogh <zoltan.balogh at ericsson.com>
> > > Reported-by: Eric Garver <e at erig.me>
> > > ---
> > >  lib/dpif-netlink.c | 120
> > > +++++++++++++++++++++++++++++++++++++++--------------
> > >  1 file changed, 90 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c index 
> > > 562f613..cf4e98f 100644
> > > --- a/lib/dpif-netlink.c
> > > +++ b/lib/dpif-netlink.c
> > > @@ -3433,34 +3433,101 @@ dpif_netlink_flow_from_ofpbuf(struct
> > > dpif_netlink_flow *flow,  }
> > >
> > >
> > > +static bool
> > > +put_exclude_packet_type(struct ofpbuf *buf, uint16_t type,
> > > +                        const struct nlattr *data, uint16_t data_len,
> > > +                        const struct nlattr *packet_type) {
> > > +    ovs_assert(NLA_ALIGN(packet_type->nla_len) == NL_A_U32_SIZE);
> > > +    size_t packet_type_len = NL_A_U32_SIZE;
> > > +    size_t first_chunk_size = (uint8_t *)packet_type - (uint8_t *)data;
> > > +    size_t second_chunk_size = data_len - first_chunk_size
> > > +                               - packet_type_len;
> > > +    uint8_t *first_attr = NULL;
> > > +    struct nlattr *next_attr = nl_attr_next(packet_type);
> > > +
> > > +    bool ethernet_present = nl_attr_find__(data, data_len,
> > > +                                           OVS_KEY_ATTR_ETHERNET);
> > > +
> > > +    first_attr = nl_msg_put_unspec_uninit(buf, type,
> > > +                                          data_len - packet_type_len);
> > > +    memcpy(first_attr, data, first_chunk_size);
> > > +    memcpy(first_attr + first_chunk_size, next_attr, 
> > > + second_chunk_size);
> > > +
> > > +    return ethernet_present;
> > > +}
> > > +
> > >  /*
> > > - * If PACKET_TYPE attribute is present in 'data', it filters 
> > > PACKET_TYPE out,
> > > - * then puts 'data' to 'buf'.
> > > + * If PACKET_TYPE attribute is present in 'data', converts it to 
> > > + ETHERNET and
> > > + * ETHERTYPE attributes, then puts 'data' to 'buf'.
> > >   */
> > >  static void
> > > -put_exclude_packet_type(struct ofpbuf *buf, uint16_t type,
> > > -                        const struct nlattr *data, uint16_t data_len)
> > > +put_convert_packet_type(struct ofpbuf *buf,
> > > +                        const struct dpif_netlink_flow *flow)
> > >  {
> > >      const struct nlattr *packet_type;
> > > +    const struct nlattr *data = flow->key;
> > > +    uint16_t data_len = flow->key_len;
> > > +    const struct nlattr *mask_data = flow->mask;
> > > +    uint16_t mask_len = flow->mask_len;
> > > +    ovs_be32 value = htonl(PT_ETH);
> > > +    bool ethernet_present = false;
> > > +
> > > +    /* Verify KEY attributes.  */
> > > +    if (data_len) {
> > > +        packet_type = nl_attr_find__(data, data_len, OVS_KEY_ATTR_PACKET_TYPE);
> > > +        if (packet_type) {
> > > +            /* Convert PACKET_TYPE Netlink attribute. */
> > > +            value = nl_attr_get_be32(packet_type);
> > > +            ethernet_present = put_exclude_packet_type(buf, OVS_FLOW_ATTR_KEY,
> > > +                                                       data, data_len,
> > > +                                                       packet_type);
> > > +            /* Put OVS_KEY_ATTR_ETHERTYPE if needed. */
> > > +            if (ntohl(value) == PT_ETH) {
> > > +                ovs_assert(ethernet_present);
> > > +            } else {
> > > +                const struct nlattr *eth_type;
> > > +                ovs_be16 ns_type = pt_ns_type_be(value);
> > >
> > > -    packet_type = nl_attr_find__(data, data_len, OVS_KEY_ATTR_PACKET_TYPE);
> > > -
> > > -    if (packet_type) {
> > > -        /* exclude PACKET_TYPE Netlink attribute. */
> > > -        ovs_assert(NLA_ALIGN(packet_type->nla_len) == NL_A_U32_SIZE);
> > > -        size_t packet_type_len = NL_A_U32_SIZE;
> > > -        size_t first_chunk_size = (uint8_t *)packet_type - (uint8_t *)data;
> > > -        size_t second_chunk_size = data_len - first_chunk_size
> > > -                                   - packet_type_len;
> > > -        uint8_t *first_attr = NULL;
> > > -        struct nlattr *next_attr = nl_attr_next(packet_type);
> > > -
> > > -        first_attr = nl_msg_put_unspec_uninit(buf, type,
> > > -                                              data_len - packet_type_len);
> > > -        memcpy(first_attr, data, first_chunk_size);
> > > -        memcpy(first_attr + first_chunk_size, next_attr, second_chunk_size);
> > > -    } else {
> > > -        nl_msg_put_unspec(buf, type, data, data_len);
> > > +                ovs_assert(ethernet_present == false);
> > > +
> > > +                eth_type = nl_attr_find__(data, data_len,
> > > +                                          OVS_KEY_ATTR_ETHERTYPE);
> > > +                if (eth_type) {
> > > +                    ovs_assert(nl_attr_get_be16(eth_type) == ns_type);
> > > +                } else {
> > > +                    nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, 
> > > + ns_type);
> > 
> > This inserts OVS_KEY_ATTR_ETHERTYPE at the top level of the message. 
> > It needs to be inserted _inside_ the nested OVS_FLOW_ATTR_KEY.

To clarify, with this patch what you end up is essentially a message
that looks like this:

    ...
    [OVS_FLOW_ATTR_KEY]
        ...
        [OVS_KEY_ATTR_IPV4] = ...
        ...
    [OVS_KEY_ATTR_ETHERTYPE] = ...  <--- the one inserted

The added OVS_KEY_ATTR_ETHERTYPE is added at the top-level of the
message. Instead it needs to be inside the
OVS_FLOW_ATTR_KEY/OVS_FLOW_ATTR_MASK like below:

    ...
    [OVS_FLOW_ATTR_KEY]
        ...
        [OVS_KEY_ATTR_IPV4] = ...
        ...
        [OVS_KEY_ATTR_ETHERTYPE] = ...  <--- the one inserted


> > 
> > > +                }
> > > +            }
> > > +        } else {
> > > +            nl_msg_put_unspec(buf, OVS_FLOW_ATTR_KEY, data, data_len);
> > > +        }
> > > +    }
> > > +
> > > +    /* Verify MASK attributes. */
> > > +    if (mask_len) {
> > > +        packet_type = nl_attr_find__(mask_data, mask_len,
> > > +                                     OVS_KEY_ATTR_PACKET_TYPE);
> > > +        if (packet_type) {
> > > +            /* Convert PACKET_TYPE Netlink attribute. */
> > > +            ethernet_present = put_exclude_packet_type(buf, OVS_FLOW_ATTR_MASK,
> > > +                                                       mask_data, mask_len,
> > > +                                                       packet_type);
> > > +            /* Put OVS_KEY_ATTR_ETHERTYPE if needed. */
> > > +            if (ntohl(value) != PT_ETH) {
> > > +                const struct nlattr *eth_type;
> > > +
> > > +                ovs_assert(ethernet_present == false);
> > > +
> > > +                eth_type = nl_attr_find__(mask_data, mask_len,
> > > +                                          OVS_KEY_ATTR_ETHERTYPE);
> > > +                if (!eth_type) {
> > > +                    nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, 
> > > + OVS_BE16_MAX);
> > 
> > Same as above.
> > 
> > > +                }
> > > +            }
> > > +        } else {
> > > +            nl_msg_put_unspec(buf, OVS_FLOW_ATTR_MASK, mask_data, mask_len);
> > > +        }
> > >      }
> > >  }
> > >
> > > @@ -3488,14 +3555,7 @@ dpif_netlink_flow_to_ofpbuf(const struct dpif_netlink_flow *flow,
> > >                         | OVS_UFID_F_OMIT_ACTIONS);
> > >      }
> > >      if (!flow->ufid_terse || !flow->ufid_present) {
> > > -        if (flow->key_len) {
> > > -            put_exclude_packet_type(buf, OVS_FLOW_ATTR_KEY, flow->key,
> > > -                                           flow->key_len);
> > > -        }
> > > -        if (flow->mask_len) {
> > > -            put_exclude_packet_type(buf, OVS_FLOW_ATTR_MASK, flow->mask,
> > > -                                           flow->mask_len);
> > > -        }
> > > +        put_convert_packet_type(buf, flow);
> > >          if (flow->actions || flow->actions_len) {
> > >              nl_msg_put_unspec(buf, OVS_FLOW_ATTR_ACTIONS,
> > >                                flow->actions, flow->actions_len);
> > > --
> > > 1.9.1
> > >
> > > _______________________________________________
> > > dev mailing list
> > > dev at openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
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