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/*
* SPDX-License-Identifier: GPL-2.0 OR Apache-2.0
* Dual-licensed under GPL version 2.0 or Apache License version 2.0
* Copyright (c) 2020 Cisco and/or its affiliates.
*/
#include <linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <bpf/bpf_helpers.h>
/*
* when compiled, debug print can be viewed with eg.
* sudo cat /sys/kernel/debug/tracing/trace_pipe
*/
#ifdef DEBUG
#define s__(n) # n
#define s_(n) s__(n)
#define x_(fmt) __FILE__ ":" s_(__LINE__) ": " fmt "\n"
#define DEBUG_PRINT_(fmt, ...) do { \
const char fmt__[] = fmt; \
bpf_trace_printk(fmt__, sizeof(fmt), ## __VA_ARGS__); } while(0)
#define DEBUG_PRINT(fmt, ...) DEBUG_PRINT_ (x_(fmt), ## __VA_ARGS__)
#else /* DEBUG */
#define DEBUG_PRINT(fmt, ...)
#endif /* DEBUG */
#define ntohs(x) __constant_ntohs(x)
SEC("maps")
struct bpf_map_def xsks_map = {
.type = BPF_MAP_TYPE_XSKMAP,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 64, /* max 64 queues per device */
};
SEC("xdp_sock")
int xdp_sock_prog(struct xdp_md *ctx) {
const void *data = (void *)(long)ctx->data;
const void *data_end = (void *)(long)ctx->data_end;
DEBUG_PRINT("rx %ld bytes packet", (long)data_end - (long)data);
/* smallest packet we are interesting in is ip-ip */
if (data + sizeof(struct ethhdr) + 2 * sizeof(struct iphdr) > data_end) {
DEBUG_PRINT("packet too small");
return XDP_PASS;
}
const struct ethhdr *eth = data;
if (eth->h_proto != ntohs(ETH_P_IP)) {
DEBUG_PRINT("unsupported eth proto %x", (int)eth->h_proto);
return XDP_PASS;
}
const struct iphdr *ip = (void *)(eth + 1);
switch (ip->protocol) {
case IPPROTO_UDP: {
const struct udphdr *udp = (void *)(ip + 1);
if (udp->dest != ntohs(4789)) { /* VxLAN dest port */
DEBUG_PRINT("unsupported udp dst port %x", (int)udp->dest);
return XDP_PASS;
}
}
case IPPROTO_IPIP:
case IPPROTO_ESP:
break;
default:
DEBUG_PRINT("unsupported ip proto %x", (int)ip->protocol);
return XDP_PASS;
}
int qid = ctx->rx_queue_index;
if (!bpf_map_lookup_elem(&xsks_map, &qid))
{
DEBUG_PRINT("no socket found");
return XDP_PASS;
}
DEBUG_PRINT("going to socket %d", qid);
return bpf_redirect_map(&xsks_map, qid, 0);
}
/* actually Dual GPLv2/Apache2, but GPLv2 as far as kernel is concerned */
SEC("license")
char _license[] = "GPL";
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