I am using mellanox Connectx6, dpdk 22

'MT2892 Family [ConnectX-6 Dx] 101d' if=ens5f1 drv=mlx5_core unused=igb_uio

I configure port with multiqueue and split traffic according to ip+port

I want to calculate the hash as the nic do, to be able to load balance traffic ( from another card ) - the information is inside the packet and not in in ip and transport layer. For this purpose i need to be able to calculate the hash value as the nic do for the first nic.

Here is the code i use to split traffic to rx queues

        /*rte flow*/

        const int MAX_PATTERN_IN_FLOW = 10;

        const int MAX_ACTIONS_IN_FLOW = 10;

        struct rte_flow_attr attr;

        struct rte_flow_item pattern[MAX_PATTERN_IN_FLOW];

        struct rte_flow_action actions[MAX_ACTIONS_IN_FLOW];

        struct rte_flow *flow;

        struct rte_flow_error error;

        memset(pattern, 0, sizeof(pattern));

        memset(actions, 0, sizeof(actions));

        /* Set the rule attribute, only ingress packets will be checked. 8< */

        memset(&attr, 0, sizeof(struct rte_flow_attr));

        attr.ingress = 1;

        pattern[0].type = RTE_FLOW_ITEM_TYPE_ETH;

        pattern[0].spec = NULL;

        pattern[1].type = RTE_FLOW_ITEM_TYPE_IPV4;

        pattern[1].spec = NULL;

        pattern[2].type = RTE_FLOW_ITEM_TYPE_GRE;

        pattern[2].spec = NULL;

        pattern[3].type = RTE_FLOW_ITEM_TYPE_ETH;

        pattern[3].spec = NULL;

        pattern[4].type = RTE_FLOW_ITEM_TYPE_IPV4;

        pattern[4].spec = NULL;

        pattern[5].type = RTE_FLOW_ITEM_TYPE_UDP;

        pattern[5].spec = NULL;

        // end the pattern array

        pattern[6].type = RTE_FLOW_ITEM_TYPE_END;

        struct rte_flow_action_rss rss_conf;

        uint16_t queues[pi_nNumRxQueues];

        rss_conf.func = RTE_ETH_HASH_FUNCTION_DEFAULT;

        uint64_t hf = RTE_ETH_RSS_IP | RTE_ETH_RSS_TCP | RTE_ETH_RSS_UDP | RTE_ETH_RSS_SCTP;

        hf &= pi_devInfo.flow_type_rss_offloads;

        rss_conf.types = hf;

        rss_conf.queue_num = pi_nNumRxQueues;

        for (int nqQueueIndex= 0; nqQueueIndex < pi_nNumRxQueues; nqQueueIndex++)

                queues[nqQueueIndex] = nqQueueIndex;

        rss_conf.queue = queues;

        rss_conf.key_len = 0;

        rss_conf.key = NULL;

        rss_conf.level = 2;

        // create the drop action

        actions[0].type = RTE_FLOW_ACTION_TYPE_RSS;

        actions[0].conf = &rss_conf;

        actions[1].type = RTE_FLOW_ACTION_TYPE_END;

        // validate and create the flow rule

        if (rte_flow_validate(pi_nPort, &attr, pattern, actions, &error)==0)

        {

            flow = rte_flow_create(pi_nPort, &attr, pattern, actions, &error);

            if(flow){//success}

            else{//error}

        }

        else {error}

    }

And this is how i tried to get the hash value saved in the mbuf, but failed

uint8_t rss_hash_default_key[] = {

    0x2c, 0xc6, 0x81, 0xd1,

    0x5b, 0xdb, 0xf4, 0xf7,

    0xfc, 0xa2, 0x83, 0x19,

    0xdb, 0x1a, 0x3e, 0x94,

    0x6b, 0x9e, 0x38, 0xd9,

    0x2c, 0x9c, 0x03, 0xd1,

    0xad, 0x99, 0x44, 0xa7,

    0xd9, 0x56, 0x3d, 0x59,

    0x06, 0x3c, 0x25, 0xf3,

    0xfc, 0x1f, 0xdc, 0x2a,

};

static inline uint32_t

do_softrss(struct rte_mbuf *m)

{

    uint32_t input_len;

    struct rte_ipv4_tuple ipv4_tuple;

    char * pRawPacket = static_cast<char*>(rte_pktmbuf_mtod(pi_mbuf, void* ));

    IpHeader * pIpHeader = (IpHeader *)(pRawPacket + offsetOfIp);

    if(pIpHeader->GetVersion()==4)

    {

        ipv4_tuple.src_addr = rte_be_to_cpu_32(pIpHeader->dwSrcAddressBigEndian);

        ipv4_tuple.dst_addr = rte_be_to_cpu_32(pIpHeader->dwDstAddressBigEndian);

        ipv4_tuple.sport = *(uint16_t*)(pRawPacket + transportLayerOffset);

        ipv4_tuple.dport = *(uint16_t*)(pRawPacket + transportLayerOffset+2);

        input_len = RTE_THASH_V4_L3_LEN;

        return rte_softrss_be((uint32_t *)&ipv4_tuple, input_len, rss_key_be);

    }

    return 0;

}

new_rss = do_softrss(mbuf_pointer);

std::cout<< std::hex << mbuf_pointer->hash.rss << " -> " << new_rss << std::dec << std::endl;

And i get a different value than the mbuf_pointer->hash.rss

5ed28a5c -> 33eb33eb

974c1896 -> 24e224e2

1edf1638 -> 21752175

8a54c19 -> 80638063

459a6f76 -> 1b351b35

1cdf1d1c -> e53be53b

****  I understand it is possible to do it, but i don't get the same value  ***

ethtool -i ens5f0

driver: mlx5_core

version: 5.8-3.0.7

firmware-version: 22.32.2004 (MT_0000000437)

expansion-rom-version:

bus-info: 0000:83:00.0

supports-statistics: yes

supports-test: yes

supports-eeprom-access: no

supports-register-dump: no

supports-priv-flags: yes