Re: [dpdk-dev] [PATCH v3] examples/ipsec-secgw: fix usage of incorrect port

[Akhil Goyal <akhil.goyal@nxp.com>]

Hi Anoob,

On 11/24/2017 3:28 PM, Anoob wrote:
>>>   static inline void
>>>   route4_pkts(struct rt_ctx *rt_ctx, struct rte_mbuf *pkts[], uint8_t 
>>> nb_pkts)
>>>   {
>>>       uint32_t hop[MAX_PKT_BURST * 2];
>>>       uint32_t dst_ip[MAX_PKT_BURST * 2];
>>> +    int32_t pkt_hop = 0;
>>>       uint16_t i, offset;
>>> +    uint16_t lpm_pkts = 0;
>>>         if (nb_pkts == 0)
>>>           return;
>>>   +    /* Need to do an LPM lookup for non-offload packets. Offload 
>>> packets
>>> +     * will have port ID in the SA
>>> +     */
>>> +
>>>       for (i = 0; i < nb_pkts; i++) {
>>> -        offset = offsetof(struct ip, ip_dst);
>>> -        dst_ip[i] = *rte_pktmbuf_mtod_offset(pkts[i],
>>> -                uint32_t *, offset);
>>> -        dst_ip[i] = rte_be_to_cpu_32(dst_ip[i]);
>>> +        if (!(pkts[i]->ol_flags & PKT_TX_SEC_OFFLOAD)) {
>>> +            /* Security offload not enabled. So an LPM lookup is
>>> +             * required to get the hop
>>> +             */
>>> +            offset = offsetof(struct ip, ip_dst);
>>> +            dst_ip[lpm_pkts] = *rte_pktmbuf_mtod_offset(pkts[i],
>>> +                    uint32_t *, offset);
>>> +            dst_ip[lpm_pkts] = rte_be_to_cpu_32(dst_ip[lpm_pkts]);
>>> +            lpm_pkts++;
>>> +        }
>>>       }
>>>   -    rte_lpm_lookup_bulk((struct rte_lpm *)rt_ctx, dst_ip, hop, 
>>> nb_pkts);
>>> +    rte_lpm_lookup_bulk((struct rte_lpm *)rt_ctx, dst_ip, hop, 
>>> lpm_pkts);
>>> +
>>> +    lpm_pkts = 0;
>>>         for (i = 0; i < nb_pkts; i++) {
>>> -        if ((hop[i] & RTE_LPM_LOOKUP_SUCCESS) == 0) {
>>> +        if (pkts[i]->ol_flags & PKT_TX_SEC_OFFLOAD) {
>>> +            /* Read hop from the SA */
>>> +            pkt_hop = get_hop_for_offload_pkt(pkts[i]);
>>> +        } else {
>>> +            /* Need to use hop returned by lookup */
>>> +            pkt_hop = hop[lpm_pkts++];
>>> +            if ((pkt_hop & RTE_LPM_LOOKUP_SUCCESS) == 0)
>>> +                pkt_hop = -1;
>>> +        }
>>> +
>> I believe the following check is redundant for non inline case. I 
>> believe get_hop_for_offload_pkt can also set the 
>> RTE_LPM_LOOKUP_SUCCESS if route is success and take the (pkt_hop & 
>> RTE_LPM_LOOKUP_SUCCESS) == 0 check outside the if else block and free 
>> the packet if it is unsuccessful.
>>
>> Same comment for route6_pkts. Checking with -1 may not be a good idea 
>> if we have a flag available for the same.
>> Others can comment.
> The problem is ipv4 & ipv6 LPM lookups return different error values, 
> but we are using a single routine to get the hop for offload packets. 
> The flag(RTE_LPM_LOOKUP_SUCCESS) is only for ipv4 lookups. For ipv6, 
> error is -1. If we need a cleaner solution, we can have ipv4 & ipv6 
> variants of "get_hop_for_offload_pkt". But that would be repetition of 
> some code.

my concern over this patch is that there is an addition of an extra 
check in the non inline case and we can get rid of that with some 
changes in the code(lib/app). Regarding route6_pkts, the code looks 
cleaner than route4_pkts

-Akhil