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/* Copyright (C) 2017 Cavium, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*/
#include "vmlinux.h"
#include "xdp_sample.bpf.h"
#include "xdp_sample_shared.h"
#define ETH_ALEN 6
#define ETH_P_8021Q 0x8100
#define ETH_P_8021AD 0x88A8
struct trie_value {
__u8 prefix[4];
__be64 value;
int ifindex;
int metric;
__be32 gw;
};
/* Key for lpm_trie */
union key_4 {
u32 b32[2];
u8 b8[8];
};
struct arp_entry {
__be64 mac;
__be32 dst;
};
struct direct_map {
struct arp_entry arp;
int ifindex;
__be64 mac;
};
/* Map for trie implementation */
struct {
__uint(type, BPF_MAP_TYPE_LPM_TRIE);
__uint(key_size, 8);
__uint(value_size, sizeof(struct trie_value));
__uint(max_entries, 50);
__uint(map_flags, BPF_F_NO_PREALLOC);
} lpm_map SEC(".maps");
/* Map for ARP table */
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, __be32);
__type(value, __be64);
__uint(max_entries, 50);
} arp_table SEC(".maps");
/* Map to keep the exact match entries in the route table */
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, __be32);
__type(value, struct direct_map);
__uint(max_entries, 50);
} exact_match SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_DEVMAP);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__uint(max_entries, 100);
} tx_port SEC(".maps");
SEC("xdp")
int xdp_router_ipv4_prog(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
u64 nh_off = sizeof(*eth);
struct datarec *rec;
__be16 h_proto;
u32 key = 0;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (rec)
NO_TEAR_INC(rec->processed);
if (data + nh_off > data_end)
goto drop;
h_proto = eth->h_proto;
if (h_proto == bpf_htons(ETH_P_8021Q) ||
h_proto == bpf_htons(ETH_P_8021AD)) {
struct vlan_hdr *vhdr;
vhdr = data + nh_off;
nh_off += sizeof(struct vlan_hdr);
if (data + nh_off > data_end)
goto drop;
h_proto = vhdr->h_vlan_encapsulated_proto;
}
switch (bpf_ntohs(h_proto)) {
case ETH_P_ARP:
if (rec)
NO_TEAR_INC(rec->xdp_pass);
return XDP_PASS;
case ETH_P_IP: {
struct iphdr *iph = data + nh_off;
struct direct_map *direct_entry;
__be64 *dest_mac, *src_mac;
int forward_to;
if (iph + 1 > data_end)
goto drop;
direct_entry = bpf_map_lookup_elem(&exact_match, &iph->daddr);
/* Check for exact match, this would give a faster lookup */
if (direct_entry && direct_entry->mac &&
direct_entry->arp.mac) {
src_mac = &direct_entry->mac;
dest_mac = &direct_entry->arp.mac;
forward_to = direct_entry->ifindex;
} else {
struct trie_value *prefix_value;
union key_4 key4;
/* Look up in the trie for lpm */
key4.b32[0] = 32;
key4.b8[4] = iph->daddr & 0xff;
key4.b8[5] = (iph->daddr >> 8) & 0xff;
key4.b8[6] = (iph->daddr >> 16) & 0xff;
key4.b8[7] = (iph->daddr >> 24) & 0xff;
prefix_value = bpf_map_lookup_elem(&lpm_map, &key4);
if (!prefix_value)
goto drop;
forward_to = prefix_value->ifindex;
src_mac = &prefix_value->value;
if (!src_mac)
goto drop;
dest_mac = bpf_map_lookup_elem(&arp_table, &iph->daddr);
if (!dest_mac) {
if (!prefix_value->gw)
goto drop;
dest_mac = bpf_map_lookup_elem(&arp_table,
&prefix_value->gw);
if (!dest_mac) {
/* Forward the packet to the kernel in
* order to trigger ARP discovery for
* the default gw.
*/
if (rec)
NO_TEAR_INC(rec->xdp_pass);
return XDP_PASS;
}
}
}
if (src_mac && dest_mac) {
int ret;
__builtin_memcpy(eth->h_dest, dest_mac, ETH_ALEN);
__builtin_memcpy(eth->h_source, src_mac, ETH_ALEN);
ret = bpf_redirect_map(&tx_port, forward_to, 0);
if (ret == XDP_REDIRECT) {
if (rec)
NO_TEAR_INC(rec->xdp_redirect);
return ret;
}
}
}
default:
break;
}
drop:
if (rec)
NO_TEAR_INC(rec->xdp_drop);
return XDP_DROP;
}
char _license[] SEC("license") = "GPL";
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