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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 | /* 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 void swap_src_dst_mac(void *data) { unsigned short *p = data; unsigned short dst[3]; dst[0] = p[0]; dst[1] = p[1]; dst[2] = p[2]; p[0] = p[3]; p[1] = p[4]; p[2] = p[5]; p[3] = dst[0]; p[4] = dst[1]; p[5] = dst[2]; } 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; if (ipproto == IPPROTO_UDP) { swap_src_dst_mac(data); if (bpf_xdp_store_bytes(ctx, 0, pkt, sizeof(pkt))) return rc; rc = XDP_TX; } return rc; } char _license[] SEC("license") = "GPL"; |