1 | /* Copyright (C) 2017 Cavium, Inc. |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify it |
4 | * under the terms of version 2 of the GNU General Public License |
5 | * as published by the Free Software Foundation. |
6 | */ |
7 | |
8 | #include "vmlinux.h" |
9 | #include "xdp_sample.bpf.h" |
10 | #include "xdp_sample_shared.h" |
11 | |
12 | #define ETH_ALEN 6 |
13 | #define ETH_P_8021Q 0x8100 |
14 | #define ETH_P_8021AD 0x88A8 |
15 | |
16 | struct trie_value { |
17 | __u8 prefix[4]; |
18 | __be64 value; |
19 | int ifindex; |
20 | int metric; |
21 | __be32 gw; |
22 | }; |
23 | |
24 | /* Key for lpm_trie */ |
25 | union key_4 { |
26 | u32 b32[2]; |
27 | u8 b8[8]; |
28 | }; |
29 | |
30 | struct arp_entry { |
31 | __be64 mac; |
32 | __be32 dst; |
33 | }; |
34 | |
35 | struct direct_map { |
36 | struct arp_entry arp; |
37 | int ifindex; |
38 | __be64 mac; |
39 | }; |
40 | |
41 | /* Map for trie implementation */ |
42 | struct { |
43 | __uint(type, BPF_MAP_TYPE_LPM_TRIE); |
44 | __uint(key_size, 8); |
45 | __uint(value_size, sizeof(struct trie_value)); |
46 | __uint(max_entries, 50); |
47 | __uint(map_flags, BPF_F_NO_PREALLOC); |
48 | } lpm_map SEC(".maps" ); |
49 | |
50 | /* Map for ARP table */ |
51 | struct { |
52 | __uint(type, BPF_MAP_TYPE_HASH); |
53 | __type(key, __be32); |
54 | __type(value, __be64); |
55 | __uint(max_entries, 50); |
56 | } arp_table SEC(".maps" ); |
57 | |
58 | /* Map to keep the exact match entries in the route table */ |
59 | struct { |
60 | __uint(type, BPF_MAP_TYPE_HASH); |
61 | __type(key, __be32); |
62 | __type(value, struct direct_map); |
63 | __uint(max_entries, 50); |
64 | } exact_match SEC(".maps" ); |
65 | |
66 | struct { |
67 | __uint(type, BPF_MAP_TYPE_DEVMAP); |
68 | __uint(key_size, sizeof(int)); |
69 | __uint(value_size, sizeof(int)); |
70 | __uint(max_entries, 100); |
71 | } tx_port SEC(".maps" ); |
72 | |
73 | SEC("xdp" ) |
74 | int xdp_router_ipv4_prog(struct xdp_md *ctx) |
75 | { |
76 | void *data_end = (void *)(long)ctx->data_end; |
77 | void *data = (void *)(long)ctx->data; |
78 | struct ethhdr *eth = data; |
79 | u64 nh_off = sizeof(*eth); |
80 | struct datarec *rec; |
81 | __be16 h_proto; |
82 | u32 key = 0; |
83 | |
84 | rec = bpf_map_lookup_elem(&rx_cnt, &key); |
85 | if (rec) |
86 | NO_TEAR_INC(rec->processed); |
87 | |
88 | if (data + nh_off > data_end) |
89 | goto drop; |
90 | |
91 | h_proto = eth->h_proto; |
92 | if (h_proto == bpf_htons(ETH_P_8021Q) || |
93 | h_proto == bpf_htons(ETH_P_8021AD)) { |
94 | struct vlan_hdr *vhdr; |
95 | |
96 | vhdr = data + nh_off; |
97 | nh_off += sizeof(struct vlan_hdr); |
98 | if (data + nh_off > data_end) |
99 | goto drop; |
100 | |
101 | h_proto = vhdr->h_vlan_encapsulated_proto; |
102 | } |
103 | |
104 | switch (bpf_ntohs(h_proto)) { |
105 | case ETH_P_ARP: |
106 | if (rec) |
107 | NO_TEAR_INC(rec->xdp_pass); |
108 | return XDP_PASS; |
109 | case ETH_P_IP: { |
110 | struct iphdr *iph = data + nh_off; |
111 | struct direct_map *direct_entry; |
112 | __be64 *dest_mac, *src_mac; |
113 | int forward_to; |
114 | |
115 | if (iph + 1 > data_end) |
116 | goto drop; |
117 | |
118 | direct_entry = bpf_map_lookup_elem(&exact_match, &iph->daddr); |
119 | |
120 | /* Check for exact match, this would give a faster lookup */ |
121 | if (direct_entry && direct_entry->mac && |
122 | direct_entry->arp.mac) { |
123 | src_mac = &direct_entry->mac; |
124 | dest_mac = &direct_entry->arp.mac; |
125 | forward_to = direct_entry->ifindex; |
126 | } else { |
127 | struct trie_value *prefix_value; |
128 | union key_4 key4; |
129 | |
130 | /* Look up in the trie for lpm */ |
131 | key4.b32[0] = 32; |
132 | key4.b8[4] = iph->daddr & 0xff; |
133 | key4.b8[5] = (iph->daddr >> 8) & 0xff; |
134 | key4.b8[6] = (iph->daddr >> 16) & 0xff; |
135 | key4.b8[7] = (iph->daddr >> 24) & 0xff; |
136 | |
137 | prefix_value = bpf_map_lookup_elem(&lpm_map, &key4); |
138 | if (!prefix_value) |
139 | goto drop; |
140 | |
141 | forward_to = prefix_value->ifindex; |
142 | src_mac = &prefix_value->value; |
143 | if (!src_mac) |
144 | goto drop; |
145 | |
146 | dest_mac = bpf_map_lookup_elem(&arp_table, &iph->daddr); |
147 | if (!dest_mac) { |
148 | if (!prefix_value->gw) |
149 | goto drop; |
150 | |
151 | dest_mac = bpf_map_lookup_elem(&arp_table, |
152 | &prefix_value->gw); |
153 | if (!dest_mac) { |
154 | /* Forward the packet to the kernel in |
155 | * order to trigger ARP discovery for |
156 | * the default gw. |
157 | */ |
158 | if (rec) |
159 | NO_TEAR_INC(rec->xdp_pass); |
160 | return XDP_PASS; |
161 | } |
162 | } |
163 | } |
164 | |
165 | if (src_mac && dest_mac) { |
166 | int ret; |
167 | |
168 | __builtin_memcpy(eth->h_dest, dest_mac, ETH_ALEN); |
169 | __builtin_memcpy(eth->h_source, src_mac, ETH_ALEN); |
170 | |
171 | ret = bpf_redirect_map(&tx_port, forward_to, 0); |
172 | if (ret == XDP_REDIRECT) { |
173 | if (rec) |
174 | NO_TEAR_INC(rec->xdp_redirect); |
175 | return ret; |
176 | } |
177 | } |
178 | } |
179 | default: |
180 | break; |
181 | } |
182 | drop: |
183 | if (rec) |
184 | NO_TEAR_INC(rec->xdp_drop); |
185 | |
186 | return XDP_DROP; |
187 | } |
188 | |
189 | char _license[] SEC("license" ) = "GPL" ; |
190 | |