1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/* 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.
*/
#define KBUILD_MODNAME "foo"
#include <uapi/linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_vlan.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include "bpf_helpers.h"
#include <linux/slab.h>
#include <net/ip_fib.h>
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 counter*/
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, u64);
__uint(max_entries, 256);
} rxcnt 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");
/* Function to set source and destination mac of the packet */
static inline void set_src_dst_mac(void *data, void *src, void *dst)
{
unsigned short *source = src;
unsigned short *dest = dst;
unsigned short *p = data;
__builtin_memcpy(p, dest, 6);
__builtin_memcpy(p + 3, source, 6);
}
/* Parse IPV4 packet to get SRC, DST IP and protocol */
static inline int parse_ipv4(void *data, u64 nh_off, void *data_end,
__be32 *src, __be32 *dest)
{
struct iphdr *iph = data + nh_off;
if (iph + 1 > data_end)
return 0;
*src = iph->saddr;
*dest = iph->daddr;
return iph->protocol;
}
SEC("xdp_router_ipv4")
int xdp_router_ipv4_prog(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
__be64 *dest_mac = NULL, *src_mac = NULL;
void *data = (void *)(long)ctx->data;
struct trie_value *prefix_value;
int rc = XDP_DROP, forward_to;
struct ethhdr *eth = data;
union key_4 key4;
long *value;
u16 h_proto;
u32 ipproto;
u64 nh_off;
nh_off = sizeof(*eth);
if (data + nh_off > data_end)
return rc;
h_proto = eth->h_proto;
if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
struct vlan_hdr *vhdr;
vhdr = data + nh_off;
nh_off += sizeof(struct vlan_hdr);
if (data + nh_off > data_end)
return rc;
h_proto = vhdr->h_vlan_encapsulated_proto;
}
if (h_proto == htons(ETH_P_ARP)) {
return XDP_PASS;
} else if (h_proto == htons(ETH_P_IP)) {
struct direct_map *direct_entry;
__be32 src_ip = 0, dest_ip = 0;
ipproto = parse_ipv4(data, nh_off, data_end, &src_ip, &dest_ip);
direct_entry = bpf_map_lookup_elem(&exact_match, &dest_ip);
/* 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 {
/* Look up in the trie for lpm*/
key4.b32[0] = 32;
key4.b8[4] = dest_ip & 0xff;
key4.b8[5] = (dest_ip >> 8) & 0xff;
key4.b8[6] = (dest_ip >> 16) & 0xff;
key4.b8[7] = (dest_ip >> 24) & 0xff;
prefix_value = bpf_map_lookup_elem(&lpm_map, &key4);
if (!prefix_value)
return XDP_DROP;
src_mac = &prefix_value->value;
if (!src_mac)
return XDP_DROP;
dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip);
if (!dest_mac) {
if (!prefix_value->gw)
return XDP_DROP;
dest_ip = prefix_value->gw;
dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip);
}
forward_to = prefix_value->ifindex;
}
} else {
ipproto = 0;
}
if (src_mac && dest_mac) {
set_src_dst_mac(data, src_mac, dest_mac);
value = bpf_map_lookup_elem(&rxcnt, &ipproto);
if (value)
*value += 1;
return bpf_redirect_map(&tx_port, forward_to, 0);
}
return rc;
}
char _license[] SEC("license") = "GPL";
|
