[dpdk-dev] [PATCH v2] app/testpmd: compute checksum in icmpecho replies
Olivier MATZ
olivier.matz at 6wind.com
Mon May 25 13:40:46 CEST 2015
Hi Adrien,
On 05/22/2015 07:03 PM, Adrien Mazarguil wrote:
> ICMP echo replies with invalid checksums may be dropped by network nodes or
> ignored by the ping utility.
>
> Signed-off-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
> Acked-by: Ivan Boule <ivan.boule at 6wind.com>
Acked-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
>
> v2:
> - Compute correct checksum value by taking overflow into account.
>
> app/test-pmd/icmpecho.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/app/test-pmd/icmpecho.c b/app/test-pmd/icmpecho.c
> index c5933f4..e249e71 100644
> --- a/app/test-pmd/icmpecho.c
> +++ b/app/test-pmd/icmpecho.c
> @@ -295,6 +295,7 @@ reply_to_icmp_echo_rqsts(struct fwd_stream *fs)
> uint16_t vlan_id;
> uint16_t arp_op;
> uint16_t arp_pro;
> + uint32_t cksum;
> uint8_t i;
> int l2_len;
> #ifdef RTE_TEST_PMD_RECORD_CORE_CYCLES
> @@ -445,7 +446,8 @@ reply_to_icmp_echo_rqsts(struct fwd_stream *fs)
> * - switch IPv4 source and destinations addresses,
> * - set IP_ICMP_ECHO_REPLY in ICMP header.
> * No need to re-compute the IP header checksum.
> - * Reset ICMP checksum.
> + * ICMP checksum is computed by assuming it is valid in the
> + * echo request and not verified.
> */
> ether_addr_copy(ð_h->s_addr, ð_addr);
> ether_addr_copy(ð_h->d_addr, ð_h->s_addr);
> @@ -454,7 +456,12 @@ reply_to_icmp_echo_rqsts(struct fwd_stream *fs)
> ip_h->src_addr = ip_h->dst_addr;
> ip_h->dst_addr = ip_addr;
> icmp_h->icmp_type = IP_ICMP_ECHO_REPLY;
> - icmp_h->icmp_cksum = 0;
> + cksum = ~icmp_h->icmp_cksum & 0xffff;
> + cksum += ~htons(IP_ICMP_ECHO_REQUEST << 8) & 0xffff;
> + cksum += htons(IP_ICMP_ECHO_REPLY << 8);
> + cksum = (cksum & 0xffff) + (cksum >> 16);
> + cksum = (cksum & 0xffff) + (cksum >> 16);
> + icmp_h->icmp_cksum = ~cksum;
> pkts_burst[nb_replies++] = pkt;
> }
>
>
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