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28 lines
812 B
Go
28 lines
812 B
Go
package sniffer
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import "fmt"
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// Computes the block_size and the num_blocks in such a way that the
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// allocated mmap buffer is close to but smaller than target_size_mb.
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// The restriction is that the block_size must be divisible by both the
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// frame size and page size.
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func afpacketComputeSize(targetSizeMb int, snaplen int, pageSize int) (
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frameSize int, blockSize int, numBlocks int, err error) {
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if snaplen < pageSize {
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frameSize = pageSize / (pageSize / snaplen)
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} else {
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frameSize = (snaplen/pageSize + 1) * pageSize
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}
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// 128 is the default from the gopacket library so just use that
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blockSize = frameSize * 128
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numBlocks = (targetSizeMb * 1024 * 1024) / blockSize
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if numBlocks == 0 {
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return 0, 0, 0, fmt.Errorf("Buffer size too small")
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}
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return frameSize, blockSize, numBlocks, nil
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}
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