| 1 | /* Copyright (c) 2016 Facebook |
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| 2 | * |
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| 3 | * This program is free software; you can redistribute it and/or |
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| 4 | * modify it under the terms of version 2 of the GNU General Public |
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| 5 | * License as published by the Free Software Foundation. |
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| 6 | */ |
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| 7 | #define KBUILD_MODNAME "foo" |
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| 8 | #include "vmlinux.h" |
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| 9 | #include "net_shared.h" |
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| 10 | #include <bpf/bpf_helpers.h> |
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| 11 | |
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| 12 | /* copy of 'struct ethhdr' without __packed */ |
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| 13 | struct eth_hdr { |
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| 14 | unsigned char h_dest[ETH_ALEN]; |
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| 15 | unsigned char h_source[ETH_ALEN]; |
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| 16 | unsigned short h_proto; |
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| 17 | }; |
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| 18 | |
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| 19 | struct { |
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| 20 | __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY); |
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| 21 | __type(key, u32); |
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| 22 | __type(value, u32); |
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| 23 | __uint(pinning, LIBBPF_PIN_BY_NAME); |
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| 24 | __uint(max_entries, 1); |
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| 25 | } test_cgrp2_array_pin SEC(".maps" ); |
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| 26 | |
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| 27 | SEC("filter" ) |
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| 28 | int handle_egress(struct __sk_buff *skb) |
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| 29 | { |
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| 30 | void *data = (void *)(long)skb->data; |
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| 31 | struct eth_hdr *eth = data; |
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| 32 | struct ipv6hdr *ip6h = data + sizeof(*eth); |
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| 33 | void *data_end = (void *)(long)skb->data_end; |
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| 34 | char dont_care_msg[] = "dont care %04x %d\n" ; |
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| 35 | char pass_msg[] = "pass\n" ; |
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| 36 | char reject_msg[] = "reject\n" ; |
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| 37 | |
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| 38 | /* single length check */ |
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| 39 | if (data + sizeof(*eth) + sizeof(*ip6h) > data_end) |
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| 40 | return TC_ACT_OK; |
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| 41 | |
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| 42 | if (eth->h_proto != bpf_htons(ETH_P_IPV6) || |
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| 43 | ip6h->nexthdr != IPPROTO_ICMPV6) { |
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| 44 | bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg), |
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| 45 | eth->h_proto, ip6h->nexthdr); |
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| 46 | return TC_ACT_OK; |
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| 47 | } else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) { |
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| 48 | bpf_trace_printk(pass_msg, sizeof(pass_msg)); |
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| 49 | return TC_ACT_OK; |
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| 50 | } else { |
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| 51 | bpf_trace_printk(reject_msg, sizeof(reject_msg)); |
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| 52 | return TC_ACT_SHOT; |
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| 53 | } |
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| 54 | } |
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| 55 | |
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| 56 | char _license[] SEC("license" ) = "GPL" ; |
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| 57 | |
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