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ba48ec5e39
This package is an initial implementation of something that can read netfilter and iptables rules from the Linux kernel without needing to shell out to an external utility; it speaks directly to the kernel using syscalls and parses the data returned. Currently this is read-only since it only knows how to parse a subset of the available data. Signed-off-by: Andrew Dunham <andrew@tailscale.com> Change-Id: Iccadf5dcc081b73268d8ccf8884c24eb6a6f1ff5
36 lines
723 B
Go
36 lines
723 B
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package linuxfw
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import (
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"encoding/hex"
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"fmt"
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"strings"
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"unicode"
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)
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func formatMaybePrintable(b []byte) string {
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// Remove a single trailing null, if any
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if len(b) > 0 && b[len(b)-1] == 0 {
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b = b[:len(b)-1]
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}
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nonprintable := strings.IndexFunc(string(b), func(r rune) bool {
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return r > unicode.MaxASCII || !unicode.IsPrint(r)
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})
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if nonprintable >= 0 {
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return "<hex>" + hex.EncodeToString(b)
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}
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return string(b)
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}
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func formatPortRange(r [2]uint16) string {
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if r == [2]uint16{0, 65535} {
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return fmt.Sprintf(`any`)
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} else if r[0] == r[1] {
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return fmt.Sprintf(`%d`, r[0])
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}
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return fmt.Sprintf(`%d-%d`, r[0], r[1])
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}
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