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ping: Fix missing TTL and ICMP error handling

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世界 2026-06-22 16:16:12 +08:00
parent 3a09076491
commit 1251022fce
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GPG key ID: CD109927C34A63C4
5 changed files with 153 additions and 60 deletions
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73
ping/destination.go
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@ -105,23 +105,29 @@ func (d *Destination) loopRead() {
}
icmpHdr := header.ICMPv4(ipHdr.Payload())
if d.needFilter() {
if icmpHdr.Type() != header.ICMPv4EchoReply {
continue
}
var requestExists bool
request := pingRequest{Source: ipHdr.DestinationAddr(), Destination: ipHdr.SourceAddr(), Identifier: icmpHdr.Ident(), Sequence: icmpHdr.Sequence()}
d.requestAccess.Lock()
_, loaded := d.requests[request]
if loaded {
requestExists = true
delete(d.requests, request)
}
d.requestAccess.Unlock()
if !requestExists {
switch icmpHdr.Type() {
case header.ICMPv4EchoReply:
request := pingRequest{Source: ipHdr.DestinationAddr(), Destination: ipHdr.SourceAddr(), Identifier: icmpHdr.Ident(), Sequence: icmpHdr.Sequence()}
d.requestAccess.Lock()
_, loaded := d.requests[request]
if loaded {
delete(d.requests, request)
}
d.requestAccess.Unlock()
if !loaded {
continue
}
d.logger.TraceContext(d.ctx, "read ICMPv4 echo reply from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
case header.ICMPv4TimeExceeded, header.ICMPv4DstUnreachable:
if !d.rewriteICMPv4Error(ipHdr, icmpHdr) {
continue
}
default:
continue
}
} else {
d.logger.TraceContext(d.ctx, "read ICMPv4 echo reply from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
}
d.logger.TraceContext(d.ctx, "read ICMPv4 echo reply from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
} else {
ipHdr := header.IPv6(buffer.Bytes())
if !ipHdr.IsValid(buffer.Len()) {
@ -191,6 +197,45 @@ func (d *Destination) WritePacket(packet *buf.Buffer) error {
return d.conn.WriteIP(packet)
}
func (d *Destination) rewriteICMPv4Error(ipHdr header.IPv4, icmpHdr header.ICMPv4) bool {
inner := icmpHdr.Payload()
if len(inner) < header.IPv4MinimumSize {
return false
}
innerIPHdr := header.IPv4(inner)
headerLen := int(innerIPHdr.HeaderLength())
if headerLen < header.IPv4MinimumSize || len(inner) < headerLen+header.ICMPv4MinimumSize {
return false
}
if innerIPHdr.TransportProtocol() != header.ICMPv4ProtocolNumber {
return false
}
innerICMP := header.ICMPv4(inner[headerLen:])
if innerICMP.Type() != header.ICMPv4Echo {
return false
}
originalIdent := ^innerICMP.Ident()
request := pingRequest{
Source: ipHdr.DestinationAddr(),
Destination: innerIPHdr.DestinationAddr(),
Identifier: originalIdent,
Sequence: innerICMP.Sequence(),
}
d.requestAccess.Lock()
_, loaded := d.requests[request]
d.requestAccess.Unlock()
if !loaded {
return false
}
innerICMP.SetIdent(originalIdent)
innerICMP.SetChecksum(header.ICMPv4Checksum(innerICMP, 0))
innerIPHdr.SetSourceAddr(ipHdr.DestinationAddr())
innerIPHdr.SetChecksum(^innerIPHdr.CalculateChecksum())
icmpHdr.SetChecksum(header.ICMPv4Checksum(icmpHdr, 0))
d.logger.TraceContext(d.ctx, "read ICMPv4 error type ", int(icmpHdr.Type()), " from ", ipHdr.SourceAddr(), " seq ", innerICMP.Sequence())
return true
}
func (d *Destination) needFilter() bool {
return !d.conn.isLinuxUnprivileged()
}