In KNI we can add functions that will be called in case the network stack makes a request. The following code shows this:
struct rte_kni *kni;
        struct rte_kni_conf conf;
        struct rte_kni_ops ops;
        struct rte_eth_dev_info dev_info;
        int ret;
        /* Clear conf at first */
        memset(&conf, 0, sizeof(conf));
        conf.core_id = 0;
        memset(&ops, 0, sizeof(ops));
        ops.port_id = ppo->id;
        ops.config_promiscusity = ippe_ppo_set_kni_promiscuous_mode;
        ops.change_mtu = ippe_ppo_set_kni_mtu;
        ops.config_network_if = ippe_ppo_set_kni_interface;
        ops.config_mac_address = ippe_ppo_set_kni_mac_address;
        kni = rte_kni_alloc(pktmbuf_pool[0], &conf, &ops);


And there is a handle_request function supplied by KNI that calls these functions when need be,
I haven't found any documentation on how to replace this functionality. I am no expert in how to set up and interact with the kernel stack, Some help on how to achieve this would be appreciated.