diff options
Diffstat (limited to 'samples/bpf/xdp_router_ipv4_kern.c')
| -rw-r--r-- | samples/bpf/xdp_router_ipv4_kern.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/samples/bpf/xdp_router_ipv4_kern.c b/samples/bpf/xdp_router_ipv4_kern.c new file mode 100644 index 0000000..993f56b --- /dev/null +++ b/samples/bpf/xdp_router_ipv4_kern.c @@ -0,0 +1,186 @@ +/* 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. + */ +#define KBUILD_MODNAME "foo" +#include <uapi/linux/bpf.h> +#include <linux/in.h> +#include <linux/if_ether.h> +#include <linux/if_packet.h> +#include <linux/if_vlan.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include "bpf_helpers.h" +#include <linux/slab.h> +#include <net/ip_fib.h> + +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 bpf_map_def SEC("maps") lpm_map = { + .type = BPF_MAP_TYPE_LPM_TRIE, + .key_size = 8, + .value_size = sizeof(struct trie_value), + .max_entries = 50, + .map_flags = BPF_F_NO_PREALLOC, +}; + +/* Map for counter*/ +struct bpf_map_def SEC("maps") rxcnt = { + .type = BPF_MAP_TYPE_PERCPU_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u64), + .max_entries = 256, +}; + +/* Map for ARP table*/ +struct bpf_map_def SEC("maps") arp_table = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(__be32), + .value_size = sizeof(__be64), + .max_entries = 50, +}; + +/* Map to keep the exact match entries in the route table*/ +struct bpf_map_def SEC("maps") exact_match = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(__be32), + .value_size = sizeof(struct direct_map), + .max_entries = 50, +}; + +struct bpf_map_def SEC("maps") tx_port = { + .type = BPF_MAP_TYPE_DEVMAP, + .key_size = sizeof(int), + .value_size = sizeof(int), + .max_entries = 100, +}; + +/* Function to set source and destination mac of the packet */ +static inline void set_src_dst_mac(void *data, void *src, void *dst) +{ + unsigned short *source = src; + unsigned short *dest = dst; + unsigned short *p = data; + + __builtin_memcpy(p, dest, 6); + __builtin_memcpy(p + 3, source, 6); +} + +/* Parse IPV4 packet to get SRC, DST IP and protocol */ +static inline int parse_ipv4(void *data, u64 nh_off, void *data_end, + __be32 *src, __be32 *dest) +{ + struct iphdr *iph = data + nh_off; + + if (iph + 1 > data_end) + return 0; + *src = iph->saddr; + *dest = iph->daddr; + return iph->protocol; +} + +SEC("xdp_router_ipv4") +int xdp_router_ipv4_prog(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + __be64 *dest_mac = NULL, *src_mac = NULL; + void *data = (void *)(long)ctx->data; + struct trie_value *prefix_value; + int rc = XDP_DROP, forward_to; + struct ethhdr *eth = data; + union key_4 key4; + long *value; + u16 h_proto; + u32 ipproto; + u64 nh_off; + + nh_off = sizeof(*eth); + if (data + nh_off > data_end) + return rc; + + h_proto = eth->h_proto; + + if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) { + struct vlan_hdr *vhdr; + + vhdr = data + nh_off; + nh_off += sizeof(struct vlan_hdr); + if (data + nh_off > data_end) + return rc; + h_proto = vhdr->h_vlan_encapsulated_proto; + } + if (h_proto == htons(ETH_P_ARP)) { + return XDP_PASS; + } else if (h_proto == htons(ETH_P_IP)) { + struct direct_map *direct_entry; + __be32 src_ip = 0, dest_ip = 0; + + ipproto = parse_ipv4(data, nh_off, data_end, &src_ip, &dest_ip); + direct_entry = bpf_map_lookup_elem(&exact_match, &dest_ip); + /* 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 { + /* Look up in the trie for lpm*/ + key4.b32[0] = 32; + key4.b8[4] = dest_ip & 0xff; + key4.b8[5] = (dest_ip >> 8) & 0xff; + key4.b8[6] = (dest_ip >> 16) & 0xff; + key4.b8[7] = (dest_ip >> 24) & 0xff; + prefix_value = bpf_map_lookup_elem(&lpm_map, &key4); + if (!prefix_value) + return XDP_DROP; + src_mac = &prefix_value->value; + if (!src_mac) + return XDP_DROP; + dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip); + if (!dest_mac) { + if (!prefix_value->gw) + return XDP_DROP; + dest_ip = prefix_value->gw; + dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip); + } + forward_to = prefix_value->ifindex; + } + } else { + ipproto = 0; + } + if (src_mac && dest_mac) { + set_src_dst_mac(data, src_mac, dest_mac); + value = bpf_map_lookup_elem(&rxcnt, &ipproto); + if (value) + *value += 1; + return bpf_redirect_map(&tx_port, forward_to, 0); + } + return rc; +} + +char _license[] SEC("license") = "GPL"; |
