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189 lines
4.0 KiB
189 lines
4.0 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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#include "vmlinux.h" |
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#include "xdp_sample.bpf.h" |
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#include "xdp_sample_shared.h" |
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#define ETH_ALEN 6 |
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#define ETH_P_8021Q 0x8100 |
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#define ETH_P_8021AD 0x88A8 |
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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 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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SEC("xdp") |
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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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void *data = (void *)(long)ctx->data; |
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struct ethhdr *eth = data; |
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u64 nh_off = sizeof(*eth); |
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struct datarec *rec; |
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__be16 h_proto; |
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u32 key = 0; |
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rec = bpf_map_lookup_elem(&rx_cnt, &key); |
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if (rec) |
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NO_TEAR_INC(rec->processed); |
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if (data + nh_off > data_end) |
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goto drop; |
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h_proto = eth->h_proto; |
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if (h_proto == bpf_htons(ETH_P_8021Q) || |
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h_proto == bpf_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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goto drop; |
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h_proto = vhdr->h_vlan_encapsulated_proto; |
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} |
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switch (bpf_ntohs(h_proto)) { |
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case ETH_P_ARP: |
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if (rec) |
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NO_TEAR_INC(rec->xdp_pass); |
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return XDP_PASS; |
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case ETH_P_IP: { |
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struct iphdr *iph = data + nh_off; |
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struct direct_map *direct_entry; |
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__be64 *dest_mac, *src_mac; |
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int forward_to; |
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if (iph + 1 > data_end) |
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goto drop; |
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direct_entry = bpf_map_lookup_elem(&exact_match, &iph->daddr); |
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/* Check for exact match, this would give a faster lookup */ |
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if (direct_entry && direct_entry->mac && |
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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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struct trie_value *prefix_value; |
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union key_4 key4; |
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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] = iph->daddr & 0xff; |
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key4.b8[5] = (iph->daddr >> 8) & 0xff; |
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key4.b8[6] = (iph->daddr >> 16) & 0xff; |
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key4.b8[7] = (iph->daddr >> 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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goto drop; |
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forward_to = prefix_value->ifindex; |
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src_mac = &prefix_value->value; |
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if (!src_mac) |
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goto drop; |
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dest_mac = bpf_map_lookup_elem(&arp_table, &iph->daddr); |
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if (!dest_mac) { |
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if (!prefix_value->gw) |
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goto drop; |
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dest_mac = bpf_map_lookup_elem(&arp_table, |
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&prefix_value->gw); |
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if (!dest_mac) { |
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/* Forward the packet to the kernel in |
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* order to trigger ARP discovery for |
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* the default gw. |
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*/ |
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if (rec) |
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NO_TEAR_INC(rec->xdp_pass); |
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return XDP_PASS; |
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} |
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} |
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} |
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if (src_mac && dest_mac) { |
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int ret; |
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__builtin_memcpy(eth->h_dest, dest_mac, ETH_ALEN); |
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__builtin_memcpy(eth->h_source, src_mac, ETH_ALEN); |
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ret = bpf_redirect_map(&tx_port, forward_to, 0); |
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if (ret == XDP_REDIRECT) { |
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if (rec) |
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NO_TEAR_INC(rec->xdp_redirect); |
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return ret; |
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} |
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} |
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} |
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default: |
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break; |
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} |
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drop: |
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if (rec) |
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NO_TEAR_INC(rec->xdp_drop); |
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return XDP_DROP; |
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} |
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char _license[] SEC("license") = "GPL";
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