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net/portmapper: check disable flags

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Signed-off-by: julianknodt <julianknodt@gmail.com>
This commit is contained in:
julianknodt
2021-08-04 16:51:10 -07:00
committed by Brad Fitzpatrick
parent 777b711d96
commit 85304d7392
3 changed files with 33 additions and 14 deletions
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11
net/portmapper/pcp.go
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@@ -45,6 +45,9 @@ type pcpMapping struct {
renewAfter time.Time
goodUntil time.Time
// TODO should this also contain an epoch?
// Doesn't seem to be used elsewhere, but can use it for validation at some point.
}
func (p *pcpMapping) GoodUntil() time.Time { return p.goodUntil }
@@ -64,8 +67,6 @@ func (p *pcpMapping) Release(ctx context.Context) {
// To create a packet which deletes a mapping, lifetimeSec should be set to 0.
// If prevPort is not known, it should be set to 0.
func buildPCPRequestMappingPacket(myIP netaddr.IP, localPort, prevPort uint16, lifetimeSec uint32) (pkt []byte) {
// note: lifetimeSec = 0 implies delete the mapping, should that be special-cased here?
// 24 byte common PCP header + 36 bytes of MAP-specific fields
pkt = make([]byte, 24+36)
pkt[0] = pcpVersion
@@ -77,12 +78,14 @@ func buildPCPRequestMappingPacket(myIP netaddr.IP, localPort, prevPort uint16, l
mapOp := pkt[24:]
rand.Read(mapOp[:12]) // 96 bit mapping nonce
// TODO should this be a UDP mapping? It looks like it supports "all protocols" with 0, but
// TODO: should this be a UDP mapping? It looks like it supports "all protocols" with 0, but
// also doesn't support a local port then.
mapOp[12] = pcpUDPMapping
binary.BigEndian.PutUint16(mapOp[16:18], localPort)
binary.BigEndian.PutUint16(mapOp[18:20], prevPort)
// TODO: This can also be the previous external IP similar to how PMP caches the
// last external IP, not sure what the benefits of that are.
v4unspec := netaddr.MustParseIP("0.0.0.0")
v4unspec16 := v4unspec.As16()
copy(mapOp[20:], v4unspec16[:])
@@ -100,7 +103,7 @@ func parsePCPMapResponse(resp []byte) (*pcpMapping, error) {
if res.ResultCode != pcpCodeOK {
return nil, fmt.Errorf("PCP response not ok, code %d", res.ResultCode)
}
// TODO don't ignore the nonce and make sure it's the same?
// TODO: don't ignore the nonce and make sure it's the same?
externalPort := binary.BigEndian.Uint16(resp[42:44])
externalIPBytes := [16]byte{}
copy(externalIPBytes[:], resp[44:])