mirror of
https://github.com/xdp-project/bpf-examples.git
synced 2024-05-06 15:54:53 +00:00
112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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#include <linux/types.h>
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#include <linux/bpf.h> /* struct bpf_cpumap_val */
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#include <bpf/bpf_helpers.h>
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#include <bpf/compiler.h>
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#define INITVAL 15485863
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//#define INITVAL 2654435761
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#include "hash_func01.h" /* SuperFastHash */
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#include <bpf/bpf_helpers.h>
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#define VLAN_MAX_DEPTH 2
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#include <xdp/parsing_helpers.h>
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#define MAX_CPUS 24
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/* This global variable is used for limiting CPU that can be selected */
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__u32 global_max_cpus = 12; /* TODO: Allow userspace to adjust this */
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/* Special map type that can XDP_REDIRECT frames to another CPU */
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struct {
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__uint(type, BPF_MAP_TYPE_CPUMAP);
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__uint(key_size, sizeof(__u32));
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__uint(value_size, sizeof(struct bpf_cpumap_val));
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__uint(max_entries, MAX_CPUS);
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} cpumap SEC(".maps");
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/* Mapping table with CPUs enabled, for hashing between */
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, MAX_CPUS);
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} cpus_enabled SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 1);
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} cpus_count SEC(".maps");
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static __always_inline
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__u32 extract_vlan_key(struct collect_vlans *vlans)
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{
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/* Combine inner and outer VLAN as a key */
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__u32 vlan_key = (vlans->id[1] << 16) | vlans->id[0];
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return vlan_key;
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}
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SEC("xdp")
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int xdp_cpumap_qinq(struct xdp_md *ctx)
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{
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void *data = (void *)(long)ctx->data;
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void *data_end = (void *)(long)ctx->data_end;
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struct collect_vlans vlans = { 0 };
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__u32 hash_key, vlan_key;
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struct ethhdr *eth;
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__u32 cpu_idx, cpu_dest = 0;
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__u32 *cpu_lookup;
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__u64 action;
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__u32 *cpu_max;
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/* These keep track of the next header type and iterator pointer */
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struct hdr_cursor nh;
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int eth_type;
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nh.pos = data;
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eth_type = parse_ethhdr_vlan(&nh, data_end, ð, &vlans);
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if (eth_type < 0) {
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action = XDP_ABORTED;
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goto out;
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}
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/* Keep ARP resolution working */
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if (eth_type == bpf_htons(ETH_P_ARP)) {
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action = XDP_PASS;
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goto out;
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}
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if (!proto_is_vlan(eth->h_proto)) {
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/* Skip non-VLAN frames */
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action = XDP_PASS;
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goto out;
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}
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int key0 = 0;
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cpu_max = bpf_map_lookup_elem(&cpus_count, &key0);
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if (!cpu_max)
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return XDP_ABORTED;
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/* Use inner+outer VLAN as key and hash based on max_cpus */
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vlan_key = extract_vlan_key(&vlans);
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hash_key = SuperFastHash((char *)&vlan_key, 4, INITVAL);
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cpu_idx = hash_key % *cpu_max;
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/* To allow excluding some CPUs, a mapping table cpus_enabled
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* translates cpu_idx to real CPU-id
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*/
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cpu_lookup = bpf_map_lookup_elem(&cpus_enabled, &cpu_idx);
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if (!cpu_lookup)
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return XDP_ABORTED;
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cpu_dest = *cpu_lookup;
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/* Notice: Userspace MUST insert entries into cpumap */
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action = bpf_redirect_map(&cpumap, cpu_dest, XDP_PASS);
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out:
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return action;
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}
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