// SPDX-License-Identifier: GPL-2.0

#include <vmlinux.h>
#include "xdp_metadata.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>

struct {
        __uint(type, BPF_MAP_TYPE_XSKMAP);
        __uint(max_entries, 256);
        __type(key, __u32);
        __type(value, __u32);
} xsk SEC(".maps");

__u64 pkts_skip = 0;
__u64 pkts_fail = 0;
__u64 pkts_redir = 0;

extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx,
                                         __u64 *timestamp) __ksym;
extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
                                    enum xdp_rss_hash_type *rss_type) __ksym;
extern int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
                                        __be16 *vlan_proto,
                                        __u16 *vlan_tci) __ksym;

SEC("xdp.frags")
int rx(struct xdp_md *ctx)
{
        void *data, *data_meta, *data_end;
        struct ipv6hdr *ip6h = NULL;
        struct udphdr *udp = NULL;
        struct iphdr *iph = NULL;
        struct xdp_meta *meta;
        struct ethhdr *eth;
        int err;

        data = (void *)(long)ctx->data;
        data_end = (void *)(long)ctx->data_end;
        eth = data;

        if (eth + 1 < data_end && (eth->h_proto == bpf_htons(ETH_P_8021AD) ||
                                   eth->h_proto == bpf_htons(ETH_P_8021Q)))
                eth = (void *)eth + sizeof(struct vlan_hdr);

        if (eth + 1 < data_end && eth->h_proto == bpf_htons(ETH_P_8021Q))
                eth = (void *)eth + sizeof(struct vlan_hdr);

        if (eth + 1 < data_end) {
                if (eth->h_proto == bpf_htons(ETH_P_IP)) {
                        iph = (void *)(eth + 1);
                        if (iph + 1 < data_end && iph->protocol == IPPROTO_UDP)
                                udp = (void *)(iph + 1);
                }
                if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {
                        ip6h = (void *)(eth + 1);
                        if (ip6h + 1 < data_end && ip6h->nexthdr == IPPROTO_UDP)
                                udp = (void *)(ip6h + 1);
                }
                if (udp && udp + 1 > data_end)
                        udp = NULL;
        }

        if (!udp) {
                __sync_add_and_fetch(&pkts_skip, 1);
                return XDP_PASS;
        }

        /* Forwarding UDP:9091 to AF_XDP */
        if (udp->dest != bpf_htons(9091)) {
                __sync_add_and_fetch(&pkts_skip, 1);
                return XDP_PASS;
        }

        err = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));
        if (err) {
                __sync_add_and_fetch(&pkts_fail, 1);
                return XDP_PASS;
        }

        data = (void *)(long)ctx->data;
        data_meta = (void *)(long)ctx->data_meta;
        meta = data_meta;

        if (meta + 1 > data) {
                __sync_add_and_fetch(&pkts_fail, 1);
                return XDP_PASS;
        }

        meta->hint_valid = 0;

        meta->xdp_timestamp = bpf_ktime_get_tai_ns();
        err = bpf_xdp_metadata_rx_timestamp(ctx, &meta->rx_timestamp);
        if (err)
                meta->rx_timestamp_err = err;
        else
                meta->hint_valid |= XDP_META_FIELD_TS;

        err = bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash,
                                       &meta->rx_hash_type);
        if (err)
                meta->rx_hash_err = err;
        else
                meta->hint_valid |= XDP_META_FIELD_RSS;

        err = bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto,
                                           &meta->rx_vlan_tci);
        if (err)
                meta->rx_vlan_tag_err = err;
        else
                meta->hint_valid |= XDP_META_FIELD_VLAN_TAG;

        __sync_add_and_fetch(&pkts_redir, 1);
        return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
}

char _license[] SEC("license") = "GPL";