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![Daniel T. Lee](/assets/img/avatar_default.png)
Since, the new syntax of BTF-defined map has been introduced,
the syntax for using maps under samples directory are mixed up.
For example, some are already using the new syntax, and some are using
existing syntax by calling them as 'legacy'.
As stated at commit abd29c9314
("libbpf: allow specifying map
definitions using BTF"), the BTF-defined map has more compatablility
with extending supported map definition features.
The commit doesn't replace all of the map to new BTF-defined map,
because some of the samples still use bpf_load instead of libbpf, which
can't properly create BTF-defined map.
This will only updates the samples which uses libbpf API for loading bpf
program. (ex. bpf_prog_load_xattr)
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
186 lines
4.4 KiB
C
186 lines
4.4 KiB
C
/* 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_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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