[dpdk-dev] [PATCH v2] app/testpmd: compute checksum in icmpecho replies
Adrien Mazarguil
adrien.mazarguil at 6wind.com
Fri May 22 19:03:12 CEST 2015
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>
---
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;
}
--
2.1.0
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