mirror of
https://github.com/soypat/lneto.git
synced 2026-08-07 08:23:42 +00:00
Pat Whittingslow
fa5ba918bb
* pcap: reuse Frame memory * slog: reduce heap allocations of addresses; also prevent heap alloc of dhcp options in pcap * dns: heapless improvement; add StackAsync buffer for more heapless operation; start thinking of errors * errors: begin standardise errors in lneto * errors: finish standardization of errors * fix merge issues * add more lneto errors to rest of package * format errors.go
55 lines
1.0 KiB
Go
55 lines
1.0 KiB
Go
package internal
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import (
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"encoding/binary"
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"github.com/soypat/lneto"
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)
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func GetIPAddr(buf []byte) (src, dst []byte, id, ipEndOff uint16, err error) {
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b0 := buf[0]
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version := b0 >> 4
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switch version {
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case 4:
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ihl := b0 & 0xf
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ipEndOff = 4 * uint16(ihl)
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id = binary.BigEndian.Uint16(buf[4:6])
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src = buf[12:16]
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dst = buf[16:20]
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case 6:
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src = buf[8:24]
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dst = buf[24:40]
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ipEndOff = 40
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default:
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err = lneto.ErrUnsupported
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}
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return src, dst, id, ipEndOff, err
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}
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func SetIPAddrs(buf []byte, id uint16, src, dst []byte) (err error) {
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var dstaddr, srcaddr []byte
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version := buf[0] >> 4
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switch version {
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case 4:
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srcaddr = buf[12:16]
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dstaddr = buf[16:20]
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if id > 0 {
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binary.BigEndian.PutUint16(buf[4:6], id)
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}
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case 6:
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srcaddr = buf[8:24]
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dstaddr = buf[24:40]
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default:
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return lneto.ErrUnsupported
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}
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if src != nil && len(srcaddr) != len(src) {
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return lneto.ErrMismatchLen
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}
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if dst != nil && len(dstaddr) != len(dst) {
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return lneto.ErrMismatchLen
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}
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copy(srcaddr, src)
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copy(dstaddr, dst)
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return nil
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}
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