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1/* Copyright (C) 2017 Cavium, Inc.2 *3 * This program is free software; you can redistribute it and/or modify it4 * under the terms of version 2 of the GNU General Public License5 * 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 613#define ETH_P_8021Q 0x810014#define ETH_P_8021AD 0x88A815 16struct 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 */25union key_4 {26 u32 b32[2];27 u8 b8[8];28};29 30struct arp_entry {31 __be64 mac;32 __be32 dst;33};34 35struct direct_map {36 struct arp_entry arp;37 int ifindex;38 __be64 mac;39};40 41/* Map for trie implementation */42struct {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 */51struct {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 */59struct {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 66struct {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 73SEC("xdp")74int 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 in155 * order to trigger ARP discovery for156 * 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 }182drop:183 if (rec)184 NO_TEAR_INC(rec->xdp_drop);185 186 return XDP_DROP;187}188 189char _license[] SEC("license") = "GPL";190