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-rw-r--r--samples/bpf/xdp_router_ipv4.bpf.c189
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";