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- /* Copyright (c) 2016 PLUMgrid
- *
- * 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/bpf_helpers.h>
- struct {
- __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
- __type(key, u32);
- __type(value, long);
- __uint(max_entries, 256);
- } rxcnt SEC(".maps");
- static int parse_ipv4(void *data, u64 nh_off, void *data_end)
- {
- struct iphdr *iph = data + nh_off;
- if (iph + 1 > data_end)
- return 0;
- return iph->protocol;
- }
- static int parse_ipv6(void *data, u64 nh_off, void *data_end)
- {
- struct ipv6hdr *ip6h = data + nh_off;
- if (ip6h + 1 > data_end)
- return 0;
- return ip6h->nexthdr;
- }
- #define XDPBUFSIZE 60
- SEC("xdp.frags")
- int xdp_prog1(struct xdp_md *ctx)
- {
- __u8 pkt[XDPBUFSIZE] = {};
- void *data_end = &pkt[XDPBUFSIZE-1];
- void *data = pkt;
- struct ethhdr *eth = data;
- int rc = XDP_DROP;
- long *value;
- u16 h_proto;
- u64 nh_off;
- u32 ipproto;
- if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
- return rc;
- nh_off = sizeof(*eth);
- if (data + nh_off > data_end)
- return rc;
- h_proto = eth->h_proto;
- /* Handle VLAN tagged packet */
- 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;
- }
- /* Handle double VLAN tagged packet */
- 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_IP))
- ipproto = parse_ipv4(data, nh_off, data_end);
- else if (h_proto == htons(ETH_P_IPV6))
- ipproto = parse_ipv6(data, nh_off, data_end);
- else
- ipproto = 0;
- value = bpf_map_lookup_elem(&rxcnt, &ipproto);
- if (value)
- *value += 1;
- return rc;
- }
- char _license[] SEC("license") = "GPL";
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