Hi,
Does anyone has idea about this ?
On 10/11/25 16:23, Dinesh wrote:
Hi everyone,
I have a requirement for adding a small custom header inside the
ip header in my VPP plugin which is of 8 bytes.
In my implementation, i increased ihl value to 7 from 5.
This works as expected in Linux kernel module, but where as in VPP
when the IHL > 5, the packet is automatically sent to the ip4-options
node, and my custom bytes are parsed as IP options (which leads to punt).
Is there any recommeneded way to:
1. Allow packets with the extended ip header to bypass the
ip4-options node, or
2. Treat the additional bytes as a custom extension instead of IP
options ?
Below is the example trace i am sharing.
IP4: 00:15:17:e7:81:be -> 00:90:27:e3:02:26
IPSEC_ESP: 14.14.14.2 -> 19.19.19.2
tos 0x00, ttl 254, length 152, checksum 0x7a0f dscp CS0 ecn NON_ECN
fragment id 0x0000
00:15:34:949021: ethernet-input
frame: flags 0x3, hw-if-index 2, sw-if-index 2
IP4: 00:15:17:e7:81:be -> 00:90:27:e3:02:26
00:15:34:949024: ip4-input-no-checksum
IPSEC_ESP: 14.14.14.2 -> 19.19.19.2
tos 0x00, ttl 254, length 152, checksum 0x7a0f dscp CS0 ecn NON_ECN
fragment id 0x0000
00:15:34:949025: ip4-full-reassembly-feature
passthrough - not a fragment
00:15:34:949026: fatpipe-worker-handoff
FATPIPE_WORKER_HANDOFF: next-worker 2 trace index 3
00:15:34:949031: fatpipe-input-ip4
fatpipe-index:1 lb-index:0
00:15:34:949035: ipsec4-input-feature
IPSEC_ESP: sa_id 3 type: 0 spd 1 policy 10 spi 3353440098
(0xc7e16f62) seq 9
00:15:34:949037: esp4-decrypt
esp: crypto aes-cbc-128 integrity sha1-96 pkt-seq 9 sa-seq 9
sa-seq-hi 0 pkt-seq-hi 0
00:15:34:949047: ip4-input-no-checksum
ICMP: 192.168.250.1 -> 192.168.250.2
version 4, header length 28
tos 0x00, ttl 63, length 92, checksum 0xd7d1 dscp CS0 ecn NON_ECN
fragment id 0xb71b, flags DONT_FRAGMENT
ICMP echo_request checksum 0xafc7 id 23
00:15:34:949048: ip4-options
option:[0xc0,0xa8,0x64,0x2]
00:15:34:949049: ip4-punt
fib:0 adj:0 flow:0x00000000
ICMP: 192.168.250.1 -> 192.168.250.2
version 4, header length 28
tos 0x00, ttl 63, length 92, checksum 0xd7d1 dscp CS0 ecn NON_ECN
fragment id 0xb71b, flags DONT_FRAGMENT
ICMP echo_request checksum 0xafc7 id 23
00:15:34:949050: ip4-punt-redirect
via redirect:8
00:15:34:949051: ip4-dvr-dpo
sw_if_index:10
00:15:34:949051: ip4-dvr-reinject
sw_if_index:10
00:15:34:949052: tap4100-output
tap4100 flags 0x0319000d
Any guidance on how to handle this cleanly within the VPP graph
would be greatly appreciated.
Thanks,
Dinesh
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