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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"; |