John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 1 | /* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com> |
| 2 | * |
| 3 | * This program is free software; you can redistribute it and/or |
| 4 | * modify it under the terms of version 2 of the GNU General Public |
| 5 | * License as published by the Free Software Foundation. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, but |
| 8 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 10 | * General Public License for more details. |
| 11 | */ |
| 12 | #define KBUILD_MODNAME "foo" |
| 13 | #include <uapi/linux/bpf.h> |
| 14 | #include <linux/in.h> |
| 15 | #include <linux/if_ether.h> |
| 16 | #include <linux/if_packet.h> |
| 17 | #include <linux/if_vlan.h> |
| 18 | #include <linux/ip.h> |
| 19 | #include <linux/ipv6.h> |
Toke Høiland-Jørgensen | 7cf245a | 2020-01-20 14:06:49 +0100 | [diff] [blame] | 20 | #include <bpf/bpf_helpers.h> |
John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 21 | |
Daniel T. Lee | 451d1dc | 2019-11-07 09:51:53 +0900 | [diff] [blame] | 22 | struct { |
| 23 | __uint(type, BPF_MAP_TYPE_ARRAY); |
| 24 | __type(key, int); |
| 25 | __type(value, int); |
| 26 | __uint(max_entries, 1); |
| 27 | } tx_port SEC(".maps"); |
John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 28 | |
Jesper Dangaard Brouer | 306da4e | 2017-08-29 16:38:06 +0200 | [diff] [blame] | 29 | /* Count RX packets, as XDP bpf_prog doesn't get direct TX-success |
| 30 | * feedback. Redirect TX errors can be caught via a tracepoint. |
| 31 | */ |
Daniel T. Lee | 451d1dc | 2019-11-07 09:51:53 +0900 | [diff] [blame] | 32 | struct { |
| 33 | __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); |
| 34 | __type(key, u32); |
| 35 | __type(value, long); |
| 36 | __uint(max_entries, 1); |
| 37 | } rxcnt SEC(".maps"); |
John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 38 | |
John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 39 | static void swap_src_dst_mac(void *data) |
| 40 | { |
| 41 | unsigned short *p = data; |
| 42 | unsigned short dst[3]; |
| 43 | |
| 44 | dst[0] = p[0]; |
| 45 | dst[1] = p[1]; |
| 46 | dst[2] = p[2]; |
| 47 | p[0] = p[3]; |
| 48 | p[1] = p[4]; |
| 49 | p[2] = p[5]; |
| 50 | p[3] = dst[0]; |
| 51 | p[4] = dst[1]; |
| 52 | p[5] = dst[2]; |
| 53 | } |
| 54 | |
| 55 | SEC("xdp_redirect") |
| 56 | int xdp_redirect_prog(struct xdp_md *ctx) |
| 57 | { |
| 58 | void *data_end = (void *)(long)ctx->data_end; |
| 59 | void *data = (void *)(long)ctx->data; |
| 60 | struct ethhdr *eth = data; |
| 61 | int rc = XDP_DROP; |
| 62 | int *ifindex, port = 0; |
| 63 | long *value; |
| 64 | u32 key = 0; |
| 65 | u64 nh_off; |
| 66 | |
| 67 | nh_off = sizeof(*eth); |
| 68 | if (data + nh_off > data_end) |
| 69 | return rc; |
| 70 | |
| 71 | ifindex = bpf_map_lookup_elem(&tx_port, &port); |
| 72 | if (!ifindex) |
| 73 | return rc; |
| 74 | |
| 75 | value = bpf_map_lookup_elem(&rxcnt, &key); |
| 76 | if (value) |
| 77 | *value += 1; |
| 78 | |
| 79 | swap_src_dst_mac(data); |
| 80 | return bpf_redirect(*ifindex, 0); |
| 81 | } |
| 82 | |
Jesper Dangaard Brouer | 306da4e | 2017-08-29 16:38:06 +0200 | [diff] [blame] | 83 | /* Redirect require an XDP bpf_prog loaded on the TX device */ |
| 84 | SEC("xdp_redirect_dummy") |
Tariq Toukan | 3edcf18 | 2017-08-31 14:16:39 +0300 | [diff] [blame] | 85 | int xdp_redirect_dummy_prog(struct xdp_md *ctx) |
Jesper Dangaard Brouer | 306da4e | 2017-08-29 16:38:06 +0200 | [diff] [blame] | 86 | { |
| 87 | return XDP_PASS; |
| 88 | } |
| 89 | |
John Fastabend | 832622e | 2017-07-17 09:27:28 -0700 | [diff] [blame] | 90 | char _license[] SEC("license") = "GPL"; |