// 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, 4);
        __type(key, __u32);
        __type(value, __u32);
} xsk SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
        __uint(max_entries, 1);
        __type(key, __u32);
        __type(value, __u32);
} prog_arr SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_DEVMAP);
        __uint(key_size, sizeof(__u32));
        __uint(value_size, sizeof(struct bpf_devmap_val));
        __uint(max_entries, 1);
} dev_map SEC(".maps");

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")
int rx(struct xdp_md *ctx)
{
        void *data, *data_meta, *data_end;
        struct ipv6hdr *ip6h = NULL;
        struct ethhdr *eth = NULL;
        struct udphdr *udp = NULL;
        struct iphdr *iph = NULL;
        struct xdp_meta *meta;
        u64 timestamp = -1;
        int ret;

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

        /* Forwarding UDP:8080 to AF_XDP */
        if (udp->dest != bpf_htons(8080))
                return XDP_PASS;

        /* Reserve enough for all custom metadata. */

        ret = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));
        if (ret != 0)
                return XDP_DROP;

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

        if (data_meta + sizeof(struct xdp_meta) > data)
                return XDP_DROP;

        meta = data_meta;

        /* Export metadata. */

        /* We expect veth bpf_xdp_metadata_rx_timestamp to return 0 HW
         * timestamp, so put some non-zero value into AF_XDP frame for
         * the userspace.
         */
        bpf_xdp_metadata_rx_timestamp(ctx, &timestamp);
        if (timestamp == 0)
                meta->rx_timestamp = 1;

        bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash, &meta->rx_hash_type);
        bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto,
                                     &meta->rx_vlan_tci);

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

SEC("xdp")
int redirect(struct xdp_md *ctx)
{
        return bpf_redirect_map(&dev_map, ctx->rx_queue_index, XDP_PASS);
}

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