47 lines
1 KiB
C
47 lines
1 KiB
C
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#include <linux/bpf.h>
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#include "bpf_helpers.h"
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#include "bpf_util.h"
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#include "bpf_endian.h"
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int _version SEC("version") = 1;
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#define bpf_printk(fmt, ...) \
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({ \
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char ____fmt[] = fmt; \
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bpf_trace_printk(____fmt, sizeof(____fmt), \
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##__VA_ARGS__); \
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})
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SEC("sk_skb1")
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int bpf_prog1(struct __sk_buff *skb)
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{
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void *data_end = (void *)(long) skb->data_end;
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void *data = (void *)(long) skb->data;
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__u32 lport = skb->local_port;
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__u32 rport = skb->remote_port;
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__u8 *d = data;
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__u32 len = (__u32) data_end - (__u32) data;
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int err;
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if (data + 10 > data_end) {
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err = bpf_skb_pull_data(skb, 10);
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if (err)
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return SK_DROP;
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data_end = (void *)(long)skb->data_end;
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data = (void *)(long)skb->data;
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if (data + 10 > data_end)
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return SK_DROP;
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}
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/* This write/read is a bit pointless but tests the verifier and
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* strparser handler for read/write pkt data and access into sk
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* fields.
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*/
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d = data;
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d[7] = 1;
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return skb->len;
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}
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char _license[] SEC("license") = "GPL";
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