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-rwxr-xr-xpkg/tcpip/stack/iptables.go22
-rwxr-xr-xpkg/tcpip/stack/iptables_targets.go23
-rw-r--r--pkg/tcpip/stack/nic.go34
-rwxr-xr-xpkg/tcpip/stack/packet_buffer.go8
4 files changed, 53 insertions, 34 deletions
diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go
index 6c0a4b24d..6b91159d4 100755
--- a/pkg/tcpip/stack/iptables.go
+++ b/pkg/tcpip/stack/iptables.go
@@ -212,6 +212,11 @@ func (it *IPTables) Check(hook Hook, pkt PacketBuffer) bool {
// CheckPackets runs pkts through the rules for hook and returns a map of packets that
// should not go forward.
//
+// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize.
+//
+// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a
+// precondition.
+//
// NOTE: unlike the Check API the returned map contains packets that should be
// dropped.
func (it *IPTables) CheckPackets(hook Hook, pkts PacketBufferList) (drop map[*PacketBuffer]struct{}) {
@@ -226,7 +231,9 @@ func (it *IPTables) CheckPackets(hook Hook, pkts PacketBufferList) (drop map[*Pa
return drop
}
-// Precondition: pkt.NetworkHeader is set.
+// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize.
+// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a
+// precondition.
func (it *IPTables) checkChain(hook Hook, pkt PacketBuffer, table Table, ruleIdx int) chainVerdict {
// Start from ruleIdx and walk the list of rules until a rule gives us
// a verdict.
@@ -271,14 +278,21 @@ func (it *IPTables) checkChain(hook Hook, pkt PacketBuffer, table Table, ruleIdx
return chainDrop
}
-// Precondition: pk.NetworkHeader is set.
+// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize.
+// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a
+// precondition.
func (it *IPTables) checkRule(hook Hook, pkt PacketBuffer, table Table, ruleIdx int) (RuleVerdict, int) {
rule := table.Rules[ruleIdx]
// If pkt.NetworkHeader hasn't been set yet, it will be contained in
- // pkt.Data.First().
+ // pkt.Data.
if pkt.NetworkHeader == nil {
- pkt.NetworkHeader = pkt.Data.First()
+ var ok bool
+ pkt.NetworkHeader, ok = pkt.Data.PullUp(header.IPv4MinimumSize)
+ if !ok {
+ // Precondition has been violated.
+ panic(fmt.Sprintf("iptables checks require IPv4 headers of at least %d bytes", header.IPv4MinimumSize))
+ }
}
// Check whether the packet matches the IP header filter.
diff --git a/pkg/tcpip/stack/iptables_targets.go b/pkg/tcpip/stack/iptables_targets.go
index 7b4543caf..8be61f4b1 100755
--- a/pkg/tcpip/stack/iptables_targets.go
+++ b/pkg/tcpip/stack/iptables_targets.go
@@ -96,9 +96,12 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) {
newPkt := pkt.Clone()
// Set network header.
- headerView := newPkt.Data.First()
+ headerView, ok := newPkt.Data.PullUp(header.IPv4MinimumSize)
+ if !ok {
+ return RuleDrop, 0
+ }
netHeader := header.IPv4(headerView)
- newPkt.NetworkHeader = headerView[:header.IPv4MinimumSize]
+ newPkt.NetworkHeader = headerView
hlen := int(netHeader.HeaderLength())
tlen := int(netHeader.TotalLength())
@@ -117,10 +120,14 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) {
if newPkt.TransportHeader != nil {
udpHeader = header.UDP(newPkt.TransportHeader)
} else {
- if len(pkt.Data.First()) < header.UDPMinimumSize {
+ if pkt.Data.Size() < header.UDPMinimumSize {
+ return RuleDrop, 0
+ }
+ hdr, ok := newPkt.Data.PullUp(header.UDPMinimumSize)
+ if !ok {
return RuleDrop, 0
}
- udpHeader = header.UDP(newPkt.Data.First())
+ udpHeader = header.UDP(hdr)
}
udpHeader.SetDestinationPort(rt.MinPort)
case header.TCPProtocolNumber:
@@ -128,10 +135,14 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) {
if newPkt.TransportHeader != nil {
tcpHeader = header.TCP(newPkt.TransportHeader)
} else {
- if len(pkt.Data.First()) < header.TCPMinimumSize {
+ if pkt.Data.Size() < header.TCPMinimumSize {
return RuleDrop, 0
}
- tcpHeader = header.TCP(newPkt.TransportHeader)
+ hdr, ok := newPkt.Data.PullUp(header.TCPMinimumSize)
+ if !ok {
+ return RuleDrop, 0
+ }
+ tcpHeader = header.TCP(hdr)
}
// TODO(gvisor.dev/issue/170): Need to recompute checksum
// and implement nat connection tracking to support TCP.
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 016dbe15e..0c2b1f36a 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -1203,12 +1203,12 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link
n.stack.stats.IP.PacketsReceived.Increment()
}
- if len(pkt.Data.First()) < netProto.MinimumPacketSize() {
+ netHeader, ok := pkt.Data.PullUp(netProto.MinimumPacketSize())
+ if !ok {
n.stack.stats.MalformedRcvdPackets.Increment()
return
}
-
- src, dst := netProto.ParseAddresses(pkt.Data.First())
+ src, dst := netProto.ParseAddresses(netHeader)
if n.stack.handleLocal && !n.isLoopback() && n.getRef(protocol, src) != nil {
// The source address is one of our own, so we never should have gotten a
@@ -1289,22 +1289,8 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link
func (n *NIC) forwardPacket(r *Route, protocol tcpip.NetworkProtocolNumber, pkt PacketBuffer) {
// TODO(b/143425874) Decrease the TTL field in forwarded packets.
-
- firstData := pkt.Data.First()
- pkt.Data.RemoveFirst()
-
- if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen == 0 {
- pkt.Header = buffer.NewPrependableFromView(firstData)
- } else {
- firstDataLen := len(firstData)
-
- // pkt.Header should have enough capacity to hold n.linkEP's headers.
- pkt.Header = buffer.NewPrependable(firstDataLen + linkHeaderLen)
-
- // TODO(b/151227689): avoid copying the packet when forwarding
- if n := copy(pkt.Header.Prepend(firstDataLen), firstData); n != firstDataLen {
- panic(fmt.Sprintf("copied %d bytes, expected %d", n, firstDataLen))
- }
+ if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen != 0 {
+ pkt.Header = buffer.NewPrependable(linkHeaderLen)
}
if err := n.linkEP.WritePacket(r, nil /* gso */, protocol, pkt); err != nil {
@@ -1332,12 +1318,13 @@ func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolN
// validly formed.
n.stack.demux.deliverRawPacket(r, protocol, pkt)
- if len(pkt.Data.First()) < transProto.MinimumPacketSize() {
+ transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize())
+ if !ok {
n.stack.stats.MalformedRcvdPackets.Increment()
return
}
- srcPort, dstPort, err := transProto.ParsePorts(pkt.Data.First())
+ srcPort, dstPort, err := transProto.ParsePorts(transHeader)
if err != nil {
n.stack.stats.MalformedRcvdPackets.Increment()
return
@@ -1375,11 +1362,12 @@ func (n *NIC) DeliverTransportControlPacket(local, remote tcpip.Address, net tcp
// ICMPv4 only guarantees that 8 bytes of the transport protocol will
// be present in the payload. We know that the ports are within the
// first 8 bytes for all known transport protocols.
- if len(pkt.Data.First()) < 8 {
+ transHeader, ok := pkt.Data.PullUp(8)
+ if !ok {
return
}
- srcPort, dstPort, err := transProto.ParsePorts(pkt.Data.First())
+ srcPort, dstPort, err := transProto.ParsePorts(transHeader)
if err != nil {
return
}
diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
index dc125f25e..7d36f8e84 100755
--- a/pkg/tcpip/stack/packet_buffer.go
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -37,7 +37,13 @@ type PacketBuffer struct {
Data buffer.VectorisedView
// Header holds the headers of outbound packets. As a packet is passed
- // down the stack, each layer adds to Header.
+ // down the stack, each layer adds to Header. Note that forwarded
+ // packets don't populate Headers on their way out -- their headers and
+ // payload are never parsed out and remain in Data.
+ //
+ // TODO(gvisor.dev/issue/170): Forwarded packets don't currently
+ // populate Header, but should. This will be doable once early parsing
+ // (https://github.com/google/gvisor/pull/1995) is supported.
Header buffer.Prependable
// These fields are used by both inbound and outbound packets. They
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 11:15:29 +0000