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70 lines
1.8 KiB
70 lines
1.8 KiB
/* Copyright (c) 2016 Facebook |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of version 2 of the GNU General Public |
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* License as published by the Free Software Foundation. |
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*/ |
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#define KBUILD_MODNAME "foo" |
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#include <uapi/linux/if_ether.h> |
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#include <uapi/linux/in6.h> |
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#include <uapi/linux/ipv6.h> |
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#include <uapi/linux/pkt_cls.h> |
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#include <uapi/linux/bpf.h> |
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#include <bpf/bpf_helpers.h> |
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/* copy of 'struct ethhdr' without __packed */ |
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struct eth_hdr { |
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unsigned char h_dest[ETH_ALEN]; |
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unsigned char h_source[ETH_ALEN]; |
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unsigned short h_proto; |
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}; |
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#define PIN_GLOBAL_NS 2 |
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struct bpf_elf_map { |
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__u32 type; |
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__u32 size_key; |
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__u32 size_value; |
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__u32 max_elem; |
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__u32 flags; |
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__u32 id; |
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__u32 pinning; |
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}; |
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struct bpf_elf_map SEC("maps") test_cgrp2_array_pin = { |
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.type = BPF_MAP_TYPE_CGROUP_ARRAY, |
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.size_key = sizeof(uint32_t), |
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.size_value = sizeof(uint32_t), |
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.pinning = PIN_GLOBAL_NS, |
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.max_elem = 1, |
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}; |
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SEC("filter") |
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int handle_egress(struct __sk_buff *skb) |
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{ |
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void *data = (void *)(long)skb->data; |
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struct eth_hdr *eth = data; |
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struct ipv6hdr *ip6h = data + sizeof(*eth); |
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void *data_end = (void *)(long)skb->data_end; |
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char dont_care_msg[] = "dont care %04x %d\n"; |
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char pass_msg[] = "pass\n"; |
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char reject_msg[] = "reject\n"; |
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/* single length check */ |
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if (data + sizeof(*eth) + sizeof(*ip6h) > data_end) |
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return TC_ACT_OK; |
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if (eth->h_proto != htons(ETH_P_IPV6) || |
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ip6h->nexthdr != IPPROTO_ICMPV6) { |
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bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg), |
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eth->h_proto, ip6h->nexthdr); |
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return TC_ACT_OK; |
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} else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) { |
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bpf_trace_printk(pass_msg, sizeof(pass_msg)); |
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return TC_ACT_OK; |
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} else { |
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bpf_trace_printk(reject_msg, sizeof(reject_msg)); |
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return TC_ACT_SHOT; |
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} |
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} |
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char _license[] SEC("license") = "GPL";
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