From: "didier.pallard" <didier.pallard@6wind.com> To: jijiang.liu@intel.com, 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, 02 Dec 2014 15:53:29 +0100 Message-ID: <547DD269.2080500@6wind.com> (raw) In-Reply-To: <1417503172-18642-4-git-send-email-jijiang.liu@intel.com> 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. 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 14:53 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 [this message] 2014-12-02 15:36 ` Ananyev, Konstantin 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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