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-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go4
-rw-r--r--pkg/tcpip/network/ipv6/ipv6.go4
-rw-r--r--pkg/tcpip/stack/iptables.go14
-rw-r--r--pkg/tcpip/stack/iptables_targets.go80
4 files changed, 71 insertions, 31 deletions
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index dda473e48..9b71738ae 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -466,7 +466,7 @@ func (e *endpoint) writePacket(r *stack.Route, pkt *stack.PacketBuffer, headerIn
// Postrouting NAT can only change the source address, and does not alter the
// route or outgoing interface of the packet.
outNicName := e.protocol.stack.FindNICNameFromID(e.nic.ID())
- if ok := e.protocol.stack.IPTables().CheckPostrouting(pkt, r, outNicName); !ok {
+ if ok := e.protocol.stack.IPTables().CheckPostrouting(pkt, r, e, outNicName); !ok {
// iptables is telling us to drop the packet.
e.stats.ip.IPTablesPostroutingDropped.Increment()
return nil
@@ -576,7 +576,7 @@ func (e *endpoint) WritePackets(r *stack.Route, pkts stack.PacketBufferList, par
// We ignore the list of NAT-ed packets here because Postrouting NAT can only
// change the source address, and does not alter the route or outgoing
// interface of the packet.
- postroutingDropped, _ := e.protocol.stack.IPTables().CheckPostroutingPackets(pkts, r, outNicName)
+ postroutingDropped, _ := e.protocol.stack.IPTables().CheckPostroutingPackets(pkts, r, e, outNicName)
stats.IPTablesPostroutingDropped.IncrementBy(uint64(len(postroutingDropped)))
for pkt := range postroutingDropped {
pkts.Remove(pkt)
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 147092c8a..600e805f8 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -788,7 +788,7 @@ func (e *endpoint) writePacket(r *stack.Route, pkt *stack.PacketBuffer, protocol
// Postrouting NAT can only change the source address, and does not alter the
// route or outgoing interface of the packet.
outNicName := e.protocol.stack.FindNICNameFromID(e.nic.ID())
- if ok := e.protocol.stack.IPTables().CheckPostrouting(pkt, r, outNicName); !ok {
+ if ok := e.protocol.stack.IPTables().CheckPostrouting(pkt, r, e, outNicName); !ok {
// iptables is telling us to drop the packet.
e.stats.ip.IPTablesPostroutingDropped.Increment()
return nil
@@ -897,7 +897,7 @@ func (e *endpoint) WritePackets(r *stack.Route, pkts stack.PacketBufferList, par
// We ignore the list of NAT-ed packets here because Postrouting NAT can only
// change the source address, and does not alter the route or outgoing
// interface of the packet.
- postroutingDropped, _ := e.protocol.stack.IPTables().CheckPostroutingPackets(pkts, r, outNicName)
+ postroutingDropped, _ := e.protocol.stack.IPTables().CheckPostroutingPackets(pkts, r, e, outNicName)
stats.IPTablesPostroutingDropped.IncrementBy(uint64(len(postroutingDropped)))
for pkt := range postroutingDropped {
pkts.Remove(pkt)
diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go
index 74c9075b4..c0ed65ece 100644
--- a/pkg/tcpip/stack/iptables.go
+++ b/pkg/tcpip/stack/iptables.go
@@ -310,8 +310,8 @@ func (it *IPTables) CheckOutput(pkt *PacketBuffer, r *Route, outNicName string)
// must be dropped if false is returned.
//
// Precondition: The packet's network and transport header must be set.
-func (it *IPTables) CheckPostrouting(pkt *PacketBuffer, r *Route, outNicName string) bool {
- return it.check(Postrouting, pkt, r, nil /* addressEP */, "" /* inNicName */, outNicName)
+func (it *IPTables) CheckPostrouting(pkt *PacketBuffer, r *Route, addressEP AddressableEndpoint, outNicName string) bool {
+ return it.check(Postrouting, pkt, r, addressEP, "" /* inNicName */, outNicName)
}
// check runs pkt through the rules for hook. It returns true when the packet
@@ -431,7 +431,7 @@ func (it *IPTables) startReaper(interval time.Duration) {
//
// Precondition: The packets' network and transport header must be set.
func (it *IPTables) CheckOutputPackets(pkts PacketBufferList, r *Route, outNicName string) (drop map[*PacketBuffer]struct{}, natPkts map[*PacketBuffer]struct{}) {
- return it.checkPackets(Output, pkts, r, outNicName)
+ return it.checkPackets(Output, pkts, r, nil /* addressEP */, outNicName)
}
// CheckPostroutingPackets performs the postrouting hook on the packets.
@@ -439,8 +439,8 @@ func (it *IPTables) CheckOutputPackets(pkts PacketBufferList, r *Route, outNicNa
// Returns a map of packets that must be dropped.
//
// Precondition: The packets' network and transport header must be set.
-func (it *IPTables) CheckPostroutingPackets(pkts PacketBufferList, r *Route, outNicName string) (drop map[*PacketBuffer]struct{}, natPkts map[*PacketBuffer]struct{}) {
- return it.checkPackets(Postrouting, pkts, r, outNicName)
+func (it *IPTables) CheckPostroutingPackets(pkts PacketBufferList, r *Route, addressEP AddressableEndpoint, outNicName string) (drop map[*PacketBuffer]struct{}, natPkts map[*PacketBuffer]struct{}) {
+ return it.checkPackets(Postrouting, pkts, r, addressEP, outNicName)
}
// checkPackets runs pkts through the rules for hook and returns a map of
@@ -450,10 +450,10 @@ func (it *IPTables) CheckPostroutingPackets(pkts PacketBufferList, r *Route, out
// dropped.
//
// Precondition: The packets' network and transport header must be set.
-func (it *IPTables) checkPackets(hook Hook, pkts PacketBufferList, r *Route, outNicName string) (drop map[*PacketBuffer]struct{}, natPkts map[*PacketBuffer]struct{}) {
+func (it *IPTables) checkPackets(hook Hook, pkts PacketBufferList, r *Route, addressEP AddressableEndpoint, outNicName string) (drop map[*PacketBuffer]struct{}, natPkts map[*PacketBuffer]struct{}) {
for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
if !pkt.NatDone {
- if ok := it.check(hook, pkt, r, nil /* addressEP */, "" /* inNicName */, outNicName); !ok {
+ if ok := it.check(hook, pkt, r, addressEP, "" /* inNicName */, outNicName); !ok {
if drop == nil {
drop = make(map[*PacketBuffer]struct{})
}
diff --git a/pkg/tcpip/stack/iptables_targets.go b/pkg/tcpip/stack/iptables_targets.go
index e8806ebdb..8310645bf 100644
--- a/pkg/tcpip/stack/iptables_targets.go
+++ b/pkg/tcpip/stack/iptables_targets.go
@@ -181,15 +181,7 @@ type SNATTarget struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
-// Action implements Target.Action.
-func (st *SNATTarget) Action(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Route, _ AddressableEndpoint) (RuleVerdict, int) {
- // Sanity check.
- if st.NetworkProtocol != pkt.NetworkProtocolNumber {
- panic(fmt.Sprintf(
- "SNATTarget.Action with NetworkProtocol %d called on packet with NetworkProtocolNumber %d",
- st.NetworkProtocol, pkt.NetworkProtocolNumber))
- }
-
+func snatAction(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Route, port uint16, address tcpip.Address) (RuleVerdict, int) {
// Packet is already manipulated.
if pkt.NatDone {
return RuleAccept, 0
@@ -200,16 +192,8 @@ func (st *SNATTarget) Action(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Rou
return RuleDrop, 0
}
- switch hook {
- case Postrouting, Input:
- case Prerouting, Output, Forward:
- panic(fmt.Sprintf("%s not supported", hook))
- default:
- panic(fmt.Sprintf("%s unrecognized", hook))
- }
-
- port := st.Port
-
+ // TODO(https://gvisor.dev/issue/5773): If the port is in use, pick a
+ // different port.
if port == 0 {
switch protocol := pkt.TransportProtocolNumber; protocol {
case header.UDPProtocolNumber:
@@ -228,13 +212,69 @@ func (st *SNATTarget) Action(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Rou
// tracking.
//
// Does nothing if the protocol does not support connection tracking.
- if conn := ct.insertSNATConn(pkt, hook, port, st.Addr); conn != nil {
+ if conn := ct.insertSNATConn(pkt, hook, port, address); conn != nil {
ct.handlePacket(pkt, hook, r)
}
return RuleAccept, 0
}
+// Action implements Target.Action.
+func (st *SNATTarget) Action(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Route, _ AddressableEndpoint) (RuleVerdict, int) {
+ // Sanity check.
+ if st.NetworkProtocol != pkt.NetworkProtocolNumber {
+ panic(fmt.Sprintf(
+ "SNATTarget.Action with NetworkProtocol %d called on packet with NetworkProtocolNumber %d",
+ st.NetworkProtocol, pkt.NetworkProtocolNumber))
+ }
+
+ switch hook {
+ case Postrouting, Input:
+ case Prerouting, Output, Forward:
+ panic(fmt.Sprintf("%s not supported", hook))
+ default:
+ panic(fmt.Sprintf("%s unrecognized", hook))
+ }
+
+ return snatAction(pkt, ct, hook, r, st.Port, st.Addr)
+}
+
+// MasqueradeTarget modifies the source port/IP in the outgoing packets.
+type MasqueradeTarget struct {
+ // NetworkProtocol is the network protocol the target is used with. It
+ // is immutable.
+ NetworkProtocol tcpip.NetworkProtocolNumber
+}
+
+// Action implements Target.Action.
+func (mt *MasqueradeTarget) Action(pkt *PacketBuffer, ct *ConnTrack, hook Hook, r *Route, addressEP AddressableEndpoint) (RuleVerdict, int) {
+ // Sanity check.
+ if mt.NetworkProtocol != pkt.NetworkProtocolNumber {
+ panic(fmt.Sprintf(
+ "MasqueradeTarget.Action with NetworkProtocol %d called on packet with NetworkProtocolNumber %d",
+ mt.NetworkProtocol, pkt.NetworkProtocolNumber))
+ }
+
+ switch hook {
+ case Postrouting:
+ case Prerouting, Input, Forward, Output:
+ panic(fmt.Sprintf("masquerade target is supported only on postrouting hook; hook = %d", hook))
+ default:
+ panic(fmt.Sprintf("%s unrecognized", hook))
+ }
+
+ // addressEP is expected to be set for the postrouting hook.
+ ep := addressEP.AcquireOutgoingPrimaryAddress(pkt.Network().DestinationAddress(), false /* allowExpired */)
+ if ep == nil {
+ // No address exists that we can use as a source address.
+ return RuleDrop, 0
+ }
+
+ address := ep.AddressWithPrefix().Address
+ ep.DecRef()
+ return snatAction(pkt, ct, hook, r, 0 /* port */, address)
+}
+
func rewritePacket(n header.Network, t header.ChecksummableTransport, updateSRCFields, fullChecksum, updatePseudoHeader bool, newPort uint16, newAddr tcpip.Address) {
if updateSRCFields {
if fullChecksum {
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-05 03:16:29 +0000