Re: [EXT] [PATCH] ipsec: fix NAT-T length calculation

[Radu Nicolau <radu.nicolau@intel.com>]

On 06-Jul-23 10:08 AM, Konstantin Ananyev wrote:
> Hi Akhil,
>
>> Hi Konstantin,
>> Can you review this patch?
>>
>>> UDP header length is included in sa->hdr_len. Take care of that in
>>> L3 header and pakcet length calculation.
>>>
>>> Fixes: 01eef5907fc3 ("ipsec: support NAT-T")
>>>
>>> Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
>>> ---
>>>   lib/ipsec/esp_outb.c | 2 +-
>>>   lib/ipsec/sa.c       | 2 +-
>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/ipsec/esp_outb.c b/lib/ipsec/esp_outb.c
>>> index 9cbd9202f6..ec87b1dce2 100644
>>> --- a/lib/ipsec/esp_outb.c
>>> +++ b/lib/ipsec/esp_outb.c
>>> @@ -198,7 +198,7 @@ outb_tun_pkt_prepare(struct rte_ipsec_sa *sa,
>>> rte_be64_t sqc,
>>>   		struct rte_udp_hdr *udph = (struct rte_udp_hdr *)
>>>   			(ph + sa->hdr_len - sizeof(struct rte_udp_hdr));
>>>   		udph->dgram_len = rte_cpu_to_be_16(mb->pkt_len - sqh_len -
>>> -				sa->hdr_l3_off - sa->hdr_len);
>>> +				sa->hdr_len + sizeof(struct rte_udp_hdr));
> To be honest, it is not clear to me why we shouldn't take into account sa->hdr_l3_off
>   any more.
> Probably the author can explain.
> Also would like author of  NAT-T support to chime in.
> Radu, any comments on that patch?
I agree, hdr_l3_off should not be ignored. Also sa->hdr_len already 
includes the size of UDP header, see line 366 in esp_outb_tun_init in 
sa.c (or the line above this change, where the udph pointer is computed 
assuming this)
> Thanks
> Konstantin
>
>>>   	}
>>>
>>>   	/* update original and new ip header fields */
>>> diff --git a/lib/ipsec/sa.c b/lib/ipsec/sa.c
>>> index 59a547637d..2297bd6d72 100644
>>> --- a/lib/ipsec/sa.c
>>> +++ b/lib/ipsec/sa.c
>>> @@ -371,7 +371,7 @@ esp_outb_tun_init(struct rte_ipsec_sa *sa, const struct
>>> rte_ipsec_sa_prm *prm)
>>>
>>>   	/* update l2_len and l3_len fields for outbound mbuf */
>>>   	sa->tx_offload.val = rte_mbuf_tx_offload(sa->hdr_l3_off,
>>> -		sa->hdr_len - sa->hdr_l3_off, 0, 0, 0, 0, 0);
>>> +		prm->tun.hdr_len - sa->hdr_l3_off, 0, 0, 0, 0, 0);
>>>
>>>   	esp_outb_init(sa, sa->hdr_len, prm->ipsec_xform.esn.value);
>>>   }
>>> --
>>> 2.40.0