[PATCH v3 1/3] node/kernel_tx: support packet transmit to kernel

[Nithin Dabilpuram]

Acked-by: Nithin Dabilpuram <ndabilpuram at marvell.com>

On Fri, Jun 2, 2023 at 9:52 PM Vamsi Attunuru <vattunuru at marvell.com> wrote:
>
> Patch adds a node to transmit the packets to kernel over
> a raw socket.
>
> Signed-off-by: Vamsi Attunuru <vattunuru at marvell.com>
> ---
>  doc/guides/prog_guide/graph_lib.rst |   9 ++
>  lib/node/kernel_tx.c                | 122 ++++++++++++++++++++++++++++
>  lib/node/kernel_tx_priv.h           |  16 ++++
>  lib/node/meson.build                |   1 +
>  4 files changed, 148 insertions(+)
>
> diff --git a/doc/guides/prog_guide/graph_lib.rst b/doc/guides/prog_guide/graph_lib.rst
> index 1cfdc86433..fa22b014f3 100644
> --- a/doc/guides/prog_guide/graph_lib.rst
> +++ b/doc/guides/prog_guide/graph_lib.rst
> @@ -392,3 +392,12 @@ null
>  ~~~~
>  This node ignores the set of objects passed to it and reports that all are
>  processed.
> +
> +kernel_tx
> +~~~~~~~~~
> +This node is an exit node that forwards the packets to kernel. It will be used
> +to forward any control plane traffic to kernel stack from DPDK. It uses a raw
> +socket interface to transmit the packets, it uses the packet's destination
> +IP address in sockaddr_in address structure and ``sendto`` function to send
> +data on the raw socket. Aftering sending the burst of packets to kernel,
> +this node free up the packet buffers.
> diff --git a/lib/node/kernel_tx.c b/lib/node/kernel_tx.c
> new file mode 100644
> index 0000000000..27d1808c71
> --- /dev/null
> +++ b/lib/node/kernel_tx.c
> @@ -0,0 +1,122 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(C) 2023 Marvell International Ltd.
> + */
> +
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <sys/socket.h>
> +#include <unistd.h>
> +
> +#include <rte_debug.h>
> +#include <rte_ethdev.h>
> +#include <rte_graph.h>
> +#include <rte_graph_worker.h>
> +#include <rte_ip.h>
> +
> +#include "kernel_tx_priv.h"
> +#include "node_private.h"
> +
> +static __rte_always_inline void
> +kernel_tx_process_mbuf(struct rte_node *node, struct rte_mbuf **mbufs, uint16_t cnt)
> +{
> +       kernel_tx_node_ctx_t *ctx = (kernel_tx_node_ctx_t *)node->ctx;
> +       struct sockaddr_in sin = {0};
> +       struct rte_ipv4_hdr *ip4;
> +       size_t len;
> +       char *buf;
> +       int i;
> +
> +       for (i = 0; i < cnt; i++) {
> +               ip4 = rte_pktmbuf_mtod(mbufs[i], struct rte_ipv4_hdr *);
> +               len = rte_pktmbuf_data_len(mbufs[i]);
> +               buf = (char *)ip4;
> +
> +               sin.sin_family = AF_INET;
> +               sin.sin_port = 0;
> +               sin.sin_addr.s_addr = ip4->dst_addr;
> +
> +               if (sendto(ctx->sock, buf, len, 0, (struct sockaddr *)&sin, sizeof(sin)) < 0)
> +                       node_err("kernel_tx", "Unable to send packets: %s\n", strerror(errno));
> +       }
> +}
> +
> +static uint16_t
> +kernel_tx_node_process(struct rte_graph *graph __rte_unused, struct rte_node *node, void **objs,
> +                        uint16_t nb_objs)
> +{
> +       struct rte_mbuf **pkts = (struct rte_mbuf **)objs;
> +       uint16_t obj_left = nb_objs;
> +
> +#define PREFETCH_CNT 4
> +
> +       while (obj_left >= 12) {
> +               /* Prefetch next-next mbufs */
> +               rte_prefetch0(pkts[8]);
> +               rte_prefetch0(pkts[9]);
> +               rte_prefetch0(pkts[10]);
> +               rte_prefetch0(pkts[11]);
> +
> +               /* Prefetch next mbuf data */
> +               rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[4], void *, pkts[4]->l2_len));
> +               rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[5], void *, pkts[5]->l2_len));
> +               rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[6], void *, pkts[6]->l2_len));
> +               rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[7], void *, pkts[7]->l2_len));
> +
> +               kernel_tx_process_mbuf(node, pkts, PREFETCH_CNT);
> +
> +               obj_left -= PREFETCH_CNT;
> +               pkts += PREFETCH_CNT;
> +       }
> +
> +       while (obj_left > 0) {
> +               kernel_tx_process_mbuf(node, pkts, 1);
> +
> +               obj_left--;
> +               pkts++;
> +       }
> +
> +       rte_pktmbuf_free_bulk((struct rte_mbuf **)objs, nb_objs);
> +
> +       return nb_objs;
> +}
> +
> +static int
> +kernel_tx_node_init(const struct rte_graph *graph __rte_unused, struct rte_node *node)
> +{
> +       kernel_tx_node_ctx_t *ctx = (kernel_tx_node_ctx_t *)node->ctx;
> +
> +       ctx->sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
> +       if (ctx->sock < 0)
> +               node_err("kernel_tx", "Unable to open RAW socket\n");
> +
> +       return 0;
> +}
> +
> +static void
> +kernel_tx_node_fini(const struct rte_graph *graph __rte_unused, struct rte_node *node)
> +{
> +       kernel_tx_node_ctx_t *ctx = (kernel_tx_node_ctx_t *)node->ctx;
> +
> +       if (ctx->sock >= 0) {
> +               close(ctx->sock);
> +               ctx->sock = -1;
> +       }
> +}
> +
> +static struct rte_node_register kernel_tx_node_base = {
> +       .process = kernel_tx_node_process,
> +       .name = "kernel_tx",
> +
> +       .init = kernel_tx_node_init,
> +       .fini = kernel_tx_node_fini,
> +
> +       .nb_edges = 0,
> +};
> +
> +struct rte_node_register *
> +kernel_tx_node_get(void)
> +{
> +       return &kernel_tx_node_base;
> +}
> +
> +RTE_NODE_REGISTER(kernel_tx_node_base);
> diff --git a/lib/node/kernel_tx_priv.h b/lib/node/kernel_tx_priv.h
> new file mode 100644
> index 0000000000..6fd8a4f2af
> --- /dev/null
> +++ b/lib/node/kernel_tx_priv.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(C) 2023 Marvell International Ltd.
> + */
> +
> +#ifndef __KERNEL_TX_PRIV_H__
> +#define __KERNEL_TX_PRIV_H__
> +
> +/* kernel_tx node context structure. */
> +typedef struct kernel_tx_node_ctx {
> +       int sock;
> +} kernel_tx_node_ctx_t;
> +
> +/* Get the pointer to kernel_tx node register structure */
> +struct rte_node_register *kernel_tx_node_get(void);
> +
> +#endif /* __KERNEL_TX_PRIV_H__ */
> diff --git a/lib/node/meson.build b/lib/node/meson.build
> index dbdf673c86..0520be23ff 100644
> --- a/lib/node/meson.build
> +++ b/lib/node/meson.build
> @@ -13,6 +13,7 @@ sources = files(
>          'ethdev_tx.c',
>          'ip4_lookup.c',
>          'ip4_rewrite.c',
> +        'kernel_tx.c',
>          'log.c',
>          'null.c',
>          'pkt_cls.c',
> --
> 2.25.1
>