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186 lines
4.4 KiB
186 lines
4.4 KiB
/* Copyright (C) 2017 Cavium, Inc. |
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* |
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* This program is free software; you can redistribute it and/or modify it |
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* under the terms of version 2 of the GNU General Public License |
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* as published by the Free Software Foundation. |
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*/ |
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#define KBUILD_MODNAME "foo" |
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#include <uapi/linux/bpf.h> |
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#include <linux/in.h> |
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#include <linux/if_ether.h> |
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#include <linux/if_packet.h> |
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#include <linux/if_vlan.h> |
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#include <linux/ip.h> |
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#include <linux/ipv6.h> |
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#include <bpf/bpf_helpers.h> |
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#include <linux/slab.h> |
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#include <net/ip_fib.h> |
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struct trie_value { |
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__u8 prefix[4]; |
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__be64 value; |
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int ifindex; |
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int metric; |
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__be32 gw; |
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}; |
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/* Key for lpm_trie*/ |
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union key_4 { |
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u32 b32[2]; |
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u8 b8[8]; |
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}; |
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struct arp_entry { |
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__be64 mac; |
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__be32 dst; |
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}; |
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struct direct_map { |
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struct arp_entry arp; |
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int ifindex; |
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__be64 mac; |
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}; |
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/* Map for trie implementation*/ |
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struct { |
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__uint(type, BPF_MAP_TYPE_LPM_TRIE); |
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__uint(key_size, 8); |
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__uint(value_size, sizeof(struct trie_value)); |
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__uint(max_entries, 50); |
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__uint(map_flags, BPF_F_NO_PREALLOC); |
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} lpm_map SEC(".maps"); |
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/* Map for counter*/ |
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struct { |
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); |
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__type(key, u32); |
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__type(value, u64); |
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__uint(max_entries, 256); |
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} rxcnt SEC(".maps"); |
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/* Map for ARP table*/ |
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struct { |
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__uint(type, BPF_MAP_TYPE_HASH); |
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__type(key, __be32); |
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__type(value, __be64); |
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__uint(max_entries, 50); |
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} arp_table SEC(".maps"); |
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/* Map to keep the exact match entries in the route table*/ |
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struct { |
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__uint(type, BPF_MAP_TYPE_HASH); |
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__type(key, __be32); |
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__type(value, struct direct_map); |
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__uint(max_entries, 50); |
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} exact_match SEC(".maps"); |
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struct { |
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__uint(type, BPF_MAP_TYPE_DEVMAP); |
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__uint(key_size, sizeof(int)); |
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__uint(value_size, sizeof(int)); |
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__uint(max_entries, 100); |
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} tx_port SEC(".maps"); |
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/* Function to set source and destination mac of the packet */ |
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static inline void set_src_dst_mac(void *data, void *src, void *dst) |
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{ |
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unsigned short *source = src; |
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unsigned short *dest = dst; |
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unsigned short *p = data; |
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__builtin_memcpy(p, dest, 6); |
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__builtin_memcpy(p + 3, source, 6); |
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} |
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/* Parse IPV4 packet to get SRC, DST IP and protocol */ |
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static inline int parse_ipv4(void *data, u64 nh_off, void *data_end, |
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__be32 *src, __be32 *dest) |
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{ |
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struct iphdr *iph = data + nh_off; |
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if (iph + 1 > data_end) |
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return 0; |
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*src = iph->saddr; |
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*dest = iph->daddr; |
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return iph->protocol; |
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} |
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SEC("xdp_router_ipv4") |
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int xdp_router_ipv4_prog(struct xdp_md *ctx) |
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{ |
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void *data_end = (void *)(long)ctx->data_end; |
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__be64 *dest_mac = NULL, *src_mac = NULL; |
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void *data = (void *)(long)ctx->data; |
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struct trie_value *prefix_value; |
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int rc = XDP_DROP, forward_to; |
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struct ethhdr *eth = data; |
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union key_4 key4; |
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long *value; |
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u16 h_proto; |
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u32 ipproto; |
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u64 nh_off; |
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nh_off = sizeof(*eth); |
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if (data + nh_off > data_end) |
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return rc; |
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h_proto = eth->h_proto; |
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if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) { |
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struct vlan_hdr *vhdr; |
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vhdr = data + nh_off; |
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nh_off += sizeof(struct vlan_hdr); |
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if (data + nh_off > data_end) |
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return rc; |
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h_proto = vhdr->h_vlan_encapsulated_proto; |
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} |
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if (h_proto == htons(ETH_P_ARP)) { |
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return XDP_PASS; |
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} else if (h_proto == htons(ETH_P_IP)) { |
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struct direct_map *direct_entry; |
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__be32 src_ip = 0, dest_ip = 0; |
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ipproto = parse_ipv4(data, nh_off, data_end, &src_ip, &dest_ip); |
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direct_entry = bpf_map_lookup_elem(&exact_match, &dest_ip); |
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/* Check for exact match, this would give a faster lookup*/ |
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if (direct_entry && direct_entry->mac && direct_entry->arp.mac) { |
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src_mac = &direct_entry->mac; |
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dest_mac = &direct_entry->arp.mac; |
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forward_to = direct_entry->ifindex; |
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} else { |
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/* Look up in the trie for lpm*/ |
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key4.b32[0] = 32; |
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key4.b8[4] = dest_ip & 0xff; |
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key4.b8[5] = (dest_ip >> 8) & 0xff; |
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key4.b8[6] = (dest_ip >> 16) & 0xff; |
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key4.b8[7] = (dest_ip >> 24) & 0xff; |
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prefix_value = bpf_map_lookup_elem(&lpm_map, &key4); |
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if (!prefix_value) |
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return XDP_DROP; |
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src_mac = &prefix_value->value; |
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if (!src_mac) |
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return XDP_DROP; |
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dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip); |
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if (!dest_mac) { |
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if (!prefix_value->gw) |
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return XDP_DROP; |
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dest_ip = prefix_value->gw; |
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dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip); |
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} |
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forward_to = prefix_value->ifindex; |
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} |
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} else { |
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ipproto = 0; |
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} |
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if (src_mac && dest_mac) { |
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set_src_dst_mac(data, src_mac, dest_mac); |
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value = bpf_map_lookup_elem(&rxcnt, &ipproto); |
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if (value) |
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*value += 1; |
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return bpf_redirect_map(&tx_port, forward_to, 0); |
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} |
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return rc; |
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} |
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char _license[] SEC("license") = "GPL";
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