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fq/format/inet/bsd_loopback_frame.go
Mattias Wadman 1ddea1ada3 interp,format: Refactor registry usage and use function helpers
Move registry to interp and add support for functions and filesystems.
This will be used later for allow formats to add own functions and fq code.

Add gojqextra function helpers to have more comfortable API to add functions.
Takes care of argument type casting and JQValue:s and some more things.

Refactor interp package to use new function helper and registry. Probably
fixes a bunch of JQValue bugs and other type errors.

Refactor out some mpeg nal things to mpeg format.

Refactor interp jq code into display.q and init.jq.

Remove undocumented aes_ctr funciton, was a test. Hopefully will add more crypto things laster.
2022-07-16 19:24:13 +02:00

65 lines
1.8 KiB
Go

package inet
// TODO: rename NetworkLayer? wireshark calls it "Family", pcap-linktype(7) calls it "network-layer protocol"
import (
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
var bsdLoopbackFrameInetPacketGroup decode.Group
func init() {
interp.RegisterFormat(decode.Format{
Name: format.BSD_LOOPBACK_FRAME,
Description: "BSD loopback frame",
Groups: []string{format.LINK_FRAME},
Dependencies: []decode.Dependency{
{Names: []string{format.INET_PACKET}, Group: &bsdLoopbackFrameInetPacketGroup},
},
DecodeFn: decodeLoopbackFrame,
})
}
const (
bsdLoopbackNetworkLayerIPv4 = 0x2
bsdLoopbackNetworkLayerIPv6 = 0x1e
)
var bsdLoopbackFrameNetworkLayerEtherType = map[uint64]int{
bsdLoopbackNetworkLayerIPv4: format.EtherTypeIPv4,
bsdLoopbackNetworkLayerIPv6: format.EtherTypeIPv6,
}
var bsdLookbackNetworkLayerMap = scalar.UToScalar{
bsdLoopbackNetworkLayerIPv4: {Sym: "ipv4", Description: `Internet protocol v4`},
bsdLoopbackNetworkLayerIPv6: {Sym: "ipv6", Description: `Internet protocol v6`},
}
func decodeLoopbackFrame(d *decode.D, in any) any {
if lfi, ok := in.(format.LinkFrameIn); ok {
if lfi.Type != format.LinkTypeNULL {
d.Fatalf("wrong link type %d", lfi.Type)
}
// TODO: where is this documented?
if lfi.IsLittleEndian {
d.Endian = decode.LittleEndian
}
}
// if no LinkFrameIn assume big endian for now
networkLayer := d.FieldU32("network_layer", bsdLookbackNetworkLayerMap, scalar.ActualHex)
d.FieldFormatOrRawLen(
"payload",
d.BitsLeft(),
bsdLoopbackFrameInetPacketGroup,
// TODO: unknown mapped to ether type 0 is ok?
format.InetPacketIn{EtherType: bsdLoopbackFrameNetworkLayerEtherType[networkLayer]},
)
return nil
}