On Mon, Jun 12, 2023 at 7:26 PM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>
> When we get packets on port 9091, we swap src/dst and send it out.
> At this point, we also request the timestamp and plumb it back
> to the userspace. The userspace simply prints the timestamp.
>
> Haven't really tested, still working on mlx5 patches...
>
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> +++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> @@ -10,7 +10,8 @@
> * - rx_hash
> *
> * TX:
> - * - TBD
> + * - UDP 9091 packets trigger TX reply
This branch on port is missing?
> +static void ping_pong(struct xsk *xsk, void *rx_packet)
> +{
> + struct ipv6hdr *ip6h = NULL;
> + struct iphdr *iph = NULL;
> + struct xdp_desc *tx_desc;
> + struct udphdr *udph;
> + struct ethhdr *eth;
> + void *data;
> + __u32 idx;
> + int ret;
> + int len;
> +
> + ret = xsk_ring_prod__reserve(&xsk->tx, 1, &idx);
> + if (ret != 1) {
> + printf("%p: failed to reserve tx slot\n", xsk);
> + return;
> + }
> +
> + tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx);
> + tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE;
> + data = xsk_umem__get_data(xsk->umem_area, tx_desc->addr);
> +
> + eth = data;
> +
> + if (eth->h_proto == htons(ETH_P_IP)) {
> + iph = (void *)(eth + 1);
> + udph = (void *)(iph + 1);
> + } else if (eth->h_proto == htons(ETH_P_IPV6)) {
> + ip6h = (void *)(eth + 1);
> + udph = (void *)(ip6h + 1);
> + } else {
> + xsk_ring_prod__cancel(&xsk->tx, 1);
> + return;
> + }
> +
> + len = ETH_HLEN;
> + if (ip6h)
> + len += ntohs(ip6h->payload_len);
sizeof(*ip6h) + ntohs(ip6h->payload_len) ?
> + if (iph)
> + len += ntohs(iph->tot_len);
> +
> + memcpy(data, rx_packet, len);
> + swap(eth->h_dest, eth->h_source, ETH_ALEN);
> + if (iph)
> + swap(&iph->saddr, &iph->daddr, 4);
need to recompute ipv4 checksum?
