1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <vmlinux.h>
4 #include "xdp_metadata.h"
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_endian.h>
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_XSKMAP);
10 __uint(max_entries, 256);
11 __type(key, __u32);
12 __type(value, __u32);
13 } xsk SEC(".maps");
14
15 extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx,
16 __u64 *timestamp) __ksym;
17 extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx,
18 __u32 *hash) __ksym;
19
20 SEC("xdp")
rx(struct xdp_md * ctx)21 int rx(struct xdp_md *ctx)
22 {
23 void *data, *data_meta, *data_end;
24 struct ipv6hdr *ip6h = NULL;
25 struct ethhdr *eth = NULL;
26 struct udphdr *udp = NULL;
27 struct iphdr *iph = NULL;
28 struct xdp_meta *meta;
29 int ret;
30
31 data = (void *)(long)ctx->data;
32 data_end = (void *)(long)ctx->data_end;
33 eth = data;
34 if (eth + 1 < data_end) {
35 if (eth->h_proto == bpf_htons(ETH_P_IP)) {
36 iph = (void *)(eth + 1);
37 if (iph + 1 < data_end && iph->protocol == IPPROTO_UDP)
38 udp = (void *)(iph + 1);
39 }
40 if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {
41 ip6h = (void *)(eth + 1);
42 if (ip6h + 1 < data_end && ip6h->nexthdr == IPPROTO_UDP)
43 udp = (void *)(ip6h + 1);
44 }
45 if (udp && udp + 1 > data_end)
46 udp = NULL;
47 }
48
49 if (!udp)
50 return XDP_PASS;
51
52 if (udp->dest != bpf_htons(9091))
53 return XDP_PASS;
54
55 bpf_printk("forwarding UDP:9091 to AF_XDP");
56
57 ret = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));
58 if (ret != 0) {
59 bpf_printk("bpf_xdp_adjust_meta returned %d", ret);
60 return XDP_PASS;
61 }
62
63 data = (void *)(long)ctx->data;
64 data_meta = (void *)(long)ctx->data_meta;
65 meta = data_meta;
66
67 if (meta + 1 > data) {
68 bpf_printk("bpf_xdp_adjust_meta doesn't appear to work");
69 return XDP_PASS;
70 }
71
72 if (!bpf_xdp_metadata_rx_timestamp(ctx, &meta->rx_timestamp))
73 bpf_printk("populated rx_timestamp with %llu", meta->rx_timestamp);
74 else
75 meta->rx_timestamp = 0; /* Used by AF_XDP as not avail signal */
76
77 if (!bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash))
78 bpf_printk("populated rx_hash with %u", meta->rx_hash);
79 else
80 meta->rx_hash = 0; /* Used by AF_XDP as not avail signal */
81
82 return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
83 }
84
85 char _license[] SEC("license") = "GPL";
86