From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com> To: didier.pallard <didier.pallard@6wind.com>, "Liu, Jijiang" <jijiang.liu@intel.com>, "dev@dpdk.org" <dev@dpdk.org> Subject: Re: [dpdk-dev] [PATCH v4 3/3] mbuf:replace the inner_l2_len and the inner_l3_len fields Date: Tue, 2 Dec 2014 15:36:48 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258213BC075@IRSMSX105.ger.corp.intel.com> (raw) In-Reply-To: <547DD269.2080500@6wind.com> Hi Didier > -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of didier.pallard > Sent: Tuesday, December 02, 2014 2:53 PM > To: Liu, Jijiang; dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v4 3/3] mbuf:replace the inner_l2_len and the inner_l3_len fields > > Hello, > > On 12/02/2014 07:52 AM, Jijiang Liu wrote: > > Replace the inner_l2_len and the inner_l3_len field with the outer_l2_len and outer_l3_len field, and rework csum forward engine > and i40e PMD due to these changes. > > > > Signed-off-by: Jijiang Liu <jijiang.liu@intel.com> > [...] > > --- a/lib/librte_mbuf/rte_mbuf.h > > +++ b/lib/librte_mbuf/rte_mbuf.h > > @@ -276,8 +276,8 @@ struct rte_mbuf { > > uint64_t tso_segsz:16; /**< TCP TSO segment size */ > > > > /* fields for TX offloading of tunnels */ > > - uint64_t inner_l3_len:9; /**< inner L3 (IP) Hdr Length. */ > > - uint64_t inner_l2_len:7; /**< inner L2 (MAC) Hdr Length. */ > > + uint64_t outer_l3_len:9; /**< Outer L3 (IP) Hdr Length. */ > > + uint64_t outer_l2_len:7; /**< Outer L2 (MAC) Hdr Length. */ > > > > /* uint64_t unused:8; */ > > }; > > Sorry for entering lately this discussion, but i'm not convinced by the > choice of outer_lx_len rather than inner_lx_len for new fields. > I agree with Olivier that new flags should only be related to the use of > new fields, to maintain coherency with oldest implementations. > But from a stack point of view, i think it is better to have lx_len > fields that target the outer layers, and to name new fields inner_lx_len. > > Let's discuss the two possibilities. > > 1) outer_lx_len fields are introduced. > In this case, the stack should have knowledge that it is processing > tunneled packets to use outer_lx_len rather than lx_len, > or stack should always use outer_lx_len packet and move those fields to > lx_len packets if no tunneling occurs... > I think it will induce extra processing that does not seem to be really > needed. > > 2) inner_lx_len fields are introduced. > In this case, the stack first uses lx_len fields. When packet should be > tunneled, lx_len fields are moved to inner_lx_len fields. > Then the stack can process the outer layer and still use the lx_len fields. Not sure, that I understood why 2) is better than 1). Let say, you have a 'normal' (non-tunnelling) packet: ether/IP/TCP In that case you still use mbuf's l2_len/l3_len/l4_len fields and setup ol_flags as usual. Then later, you decided to 'tunnel' that packet. So you just fill mbuf's outer_l2_len/outer_l3_len, setup TX_OUTER_* and TX_TUNNEL_* bits in ol_flags and probably update l2_len. l3_len/l4_len and ol_flags bits set for them remain intact. That's with 1) With 2) - you'll have to move l3_len/l4_len to inner_lx_len. And I suppose ol_flags values too: ol_flags &= ~PKT_ IP_CKSUM; ol_flgas |= PKT_INNER_IP_CKSUM ? And same for L4_CKSUM flags too? Konstantin > > For example: > an eth/IP/TCP forged packet will look like this: > > Ether/IP/UDP/xxx > m->flags = IP_CKSUM > m->l2_len = sizeof(ether) > m->l3_len = sizeof(ip) > m->l4_len = sizeof(udp) > m->inner_l2_len = 0 > m->inner_l3_len = 0 > > When entering tunnel for example a VXLAN interface, lx_len will be moved > to inner_lx_len > > Ether/IP/UDP/xxx > m->flags = INNER_IP_CKSUM > m->l2_len = 0 > m->l3_len = 0 > m->l4_len = 0 > m->inner_l2_len = sizeof(ether) > m->inner_l3_len = sizeof(ip) > > > once complete encapsulation is processed by the stack, the packet will > look like > > Ether/IP/UDP/VXLAN/Ether/IP/UDP/xxx > m->flags = IP_CKSUM | INNER_IP_CKSUM > m->l2_len = sizeof(ether) > m->l3_len = sizeof(ip) > m->l4_len = sizeof(udp) > m->inner_l2_len = sizeof(ether) + sizeof (vxlan) > m->inner_l3_len = sizeof(ip) > > > didier >
next prev parent reply other threads:[~2014-12-02 16:15 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-12-02 6:52 [dpdk-dev] [PATCH v4 0/3] i40e VXLAN TX checksum rework Jijiang Liu 2014-12-02 6:52 ` [dpdk-dev] [PATCH v4 1/3] mbuf:redefine three TX ol_flags Jijiang Liu 2014-12-02 6:52 ` [dpdk-dev] [PATCH v4 2/3] mbuf:add three TX ol_flags and repalce PKT_TX_VXLAN_CKSUM Jijiang Liu 2014-12-02 6:52 ` [dpdk-dev] [PATCH v4 3/3] mbuf:replace the inner_l2_len and the inner_l3_len fields Jijiang Liu 2014-12-02 14:53 ` didier.pallard 2014-12-02 15:36 ` Ananyev, Konstantin [this message] 2014-12-03 8:57 ` Olivier MATZ 2014-12-03 11:11 ` Ananyev, Konstantin 2014-12-03 11:27 ` Olivier MATZ
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