> -----Original Message----- > From: Akhil Goyal [mailto:akhil.go...@nxp.com] > Sent: Tuesday, January 16, 2018 6:30 AM > To: Nicolau, Radu <radu.nico...@intel.com>; dev@dpdk.org > Cc: De Lara Guarch, Pablo <pablo.de.lara.gua...@intel.com>; > hemant.agra...@nxp.com > Subject: Re: [PATCH] examples/ipsec-secgw: update incremental checksum > > Hi Radu, > On 1/15/2018 8:10 PM, Nicolau, Radu wrote: > > > > > >> -----Original Message----- > >> From: Akhil Goyal [mailto:akhil.go...@nxp.com] > >> Sent: Monday, January 15, 2018 12:48 PM > >> To: dev@dpdk.org > >> Cc: De Lara Guarch, Pablo <pablo.de.lara.gua...@intel.com>; > >> hemant.agra...@nxp.com; Nicolau, Radu <radu.nico...@intel.com> > >> Subject: Re: [PATCH] examples/ipsec-secgw: update incremental > >> checksum > >> > >> On 1/15/2018 6:12 PM, Akhil Goyal wrote: > >>> When TTL is decremented or ecn is updated in IP header before > >>> forwarding the packet, checksum needs to be updated. > >>> > >>> In this patch an incremental checksum is added for ipv4 case. > >>> > >>> Signed-off-by: Akhil Goyal <akhil.go...@nxp.com> > >>> --- > >> This patch is an update to a very old patch which was rejected earlier. > >> http://dpdk.org/dev/patchwork/patch/16113/ > >> > >>> examples/ipsec-secgw/ipip.h | 19 ++++++++++++++++++- > >>> 1 file changed, 18 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/examples/ipsec-secgw/ipip.h > >>> b/examples/ipsec-secgw/ipip.h index fb6a6fa..13b8455 100644 > >>> --- a/examples/ipsec-secgw/ipip.h > >>> +++ b/examples/ipsec-secgw/ipip.h > >>> @@ -27,6 +27,10 @@ ipip_outbound(struct rte_mbuf *m, uint32_t > >>> offset, > >> uint32_t is_ipv6, > >>> if (inip4->ip_v == IPVERSION) { > >>> /* XXX This should be done by the forwarding engine > >>> instead > >> */ > >>> inip4->ip_ttl -= 1; > >>> + if (inip4->ip_sum >= rte_cpu_to_be_16(0xffff - 0x100)) > >>> + inip4->ip_sum += rte_cpu_to_be_16(0x100) + 1; > >>> + else > >>> + inip4->ip_sum += rte_cpu_to_be_16(0x100); > >>> ds_ecn = inip4->ip_tos; > >>> } else { > >>> inip6 = (struct ip6_hdr *)inip4; @@ -95,8 +99,17 @@ > >>> ip6ip_outbound(struct rte_mbuf *m, uint32_t offset, > >>> static inline void > >>> ip4_ecn_setup(struct ip *ip4) > >>> { > >>> - if (ip4->ip_tos & IPTOS_ECN_MASK) > >>> + if (ip4->ip_tos & IPTOS_ECN_MASK) { > >>> + unsigned long sum; > >>> + uint8_t old; > >>> + > >>> + old = ip4->ip_tos; > >>> ip4->ip_tos |= IPTOS_ECN_CE; > >>> + sum = old + (~(*(uint8_t *)&ip4->ip_tos) & 0xff); > >>> + sum += rte_be_to_cpu_16(ip4->ip_sum); > >>> + sum = (sum & 0xffff) + (sum >> 16); > >>> + ip4->ip_sum = rte_cpu_to_be_16(sum + (sum >> 16)); > >>> + } > >>> } > >>> > >>> static inline void > >>> @@ -140,6 +153,10 @@ ipip_inbound(struct rte_mbuf *m, uint32_t > offset) > >>> ip4_ecn_setup(inip4); > >>> /* XXX This should be done by the forwarding engine > >>> instead > >> */ > >>> inip4->ip_ttl -= 1; > >>> + if (inip4->ip_sum >= rte_cpu_to_be_16(0xffff - 0x100)) > >>> + inip4->ip_sum += rte_cpu_to_be_16(0x100) + 1; > >>> + else > >>> + inip4->ip_sum += rte_cpu_to_be_16(0x100); > >>> m->packet_type &= ~RTE_PTYPE_L4_MASK; > >>> if (inip4->ip_p == IPPROTO_UDP) > >>> m->packet_type |= RTE_PTYPE_L4_UDP; > >>> > > > > I think instead of manipulating the checksum in this way it will be better > > to > use rte_ipv4_cksum to re-compute it, unless the performance penalty is too > significant. > > > There would be unnecessary wastage of cycles. This way of updating the > checksum is implemented as per the RFC1141 > https://tools.ietf.org/html/rfc1141 > Do you see any issue in this way of updating the checksum? No, I just tought that it will make the code look nicer.
Acked-by: Radu Nicolau <radu.nico...@intel.com>
