diff options
Diffstat (limited to 'samples/bpf/xdp_router_ipv4.bpf.c')
| -rw-r--r-- | samples/bpf/xdp_router_ipv4.bpf.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/samples/bpf/xdp_router_ipv4.bpf.c b/samples/bpf/xdp_router_ipv4.bpf.c new file mode 100644 index 0000000000..0643330d1d --- /dev/null +++ b/samples/bpf/xdp_router_ipv4.bpf.c @@ -0,0 +1,189 @@ +/* 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. + */ + +#include "vmlinux.h" +#include "xdp_sample.bpf.h" +#include "xdp_sample_shared.h" + +#define ETH_ALEN 6 +#define ETH_P_8021Q 0x8100 +#define ETH_P_8021AD 0x88A8 + +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 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"); + +SEC("xdp") +int xdp_router_ipv4_prog(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + struct ethhdr *eth = data; + u64 nh_off = sizeof(*eth); + struct datarec *rec; + __be16 h_proto; + u32 key = 0; + + rec = bpf_map_lookup_elem(&rx_cnt, &key); + if (rec) + NO_TEAR_INC(rec->processed); + + if (data + nh_off > data_end) + goto drop; + + h_proto = eth->h_proto; + if (h_proto == bpf_htons(ETH_P_8021Q) || + h_proto == bpf_htons(ETH_P_8021AD)) { + struct vlan_hdr *vhdr; + + vhdr = data + nh_off; + nh_off += sizeof(struct vlan_hdr); + if (data + nh_off > data_end) + goto drop; + + h_proto = vhdr->h_vlan_encapsulated_proto; + } + + switch (bpf_ntohs(h_proto)) { + case ETH_P_ARP: + if (rec) + NO_TEAR_INC(rec->xdp_pass); + return XDP_PASS; + case ETH_P_IP: { + struct iphdr *iph = data + nh_off; + struct direct_map *direct_entry; + __be64 *dest_mac, *src_mac; + int forward_to; + + if (iph + 1 > data_end) + goto drop; + + direct_entry = bpf_map_lookup_elem(&exact_match, &iph->daddr); + + /* 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 { + struct trie_value *prefix_value; + union key_4 key4; + + /* Look up in the trie for lpm */ + key4.b32[0] = 32; + key4.b8[4] = iph->daddr & 0xff; + key4.b8[5] = (iph->daddr >> 8) & 0xff; + key4.b8[6] = (iph->daddr >> 16) & 0xff; + key4.b8[7] = (iph->daddr >> 24) & 0xff; + + prefix_value = bpf_map_lookup_elem(&lpm_map, &key4); + if (!prefix_value) + goto drop; + + forward_to = prefix_value->ifindex; + src_mac = &prefix_value->value; + if (!src_mac) + goto drop; + + dest_mac = bpf_map_lookup_elem(&arp_table, &iph->daddr); + if (!dest_mac) { + if (!prefix_value->gw) + goto drop; + + dest_mac = bpf_map_lookup_elem(&arp_table, + &prefix_value->gw); + if (!dest_mac) { + /* Forward the packet to the kernel in + * order to trigger ARP discovery for + * the default gw. + */ + if (rec) + NO_TEAR_INC(rec->xdp_pass); + return XDP_PASS; + } + } + } + + if (src_mac && dest_mac) { + int ret; + + __builtin_memcpy(eth->h_dest, dest_mac, ETH_ALEN); + __builtin_memcpy(eth->h_source, src_mac, ETH_ALEN); + + ret = bpf_redirect_map(&tx_port, forward_to, 0); + if (ret == XDP_REDIRECT) { + if (rec) + NO_TEAR_INC(rec->xdp_redirect); + return ret; + } + } + } + default: + break; + } +drop: + if (rec) + NO_TEAR_INC(rec->xdp_drop); + + return XDP_DROP; +} + +char _license[] SEC("license") = "GPL"; |