tailcfg: add Node.SelfNodeV4MasqAddrForThisPeer

This only adds the field, to be used in a future commit.

Updates tailscale/corp#8020

Co-authored-by: Melanie Warrick <warrick@tailscale.com>
Signed-off-by: Maisem Ali <maisem@tailscale.com>

tailcfg/tailcfg.go

@@ -273,6 +273,21 @@ type Node struct {
 	// the client, this is calculated client-side based on a timestamp sent
 	// from control, to avoid clock skew issues.
 	Expired bool `json:",omitempty"`
+
+	// SelfNodeV4MasqAddrForThisPeer is the IPv4 that this peer knows the current node as.
+	// It may be empty if the peer knows the current node by its native
+	// IPv4 address.
+	// This field is only populated in a MapResponse for peers and not
+	// for the current node.
+	//
+	// If set, it should be used to masquerade traffic originating from the
+	// current node to this peer. The masquerade address is only relevant
+	// for this peer and not for other peers.
+	//
+	// This only applies to traffic originating from the current node to the
+	// peer or any of its subnets. Traffic originating from subnet routes will
+	// not be masqueraded (e.g. in case of --snat-subnet-routes).
+	SelfNodeV4MasqAddrForThisPeer netip.Addr `json:",omitempty"`
 }
 
 // DisplayName returns the user-facing name for a node which should

tailcfg/tailcfg_clone.go

@@ -68,36 +68,37 @@ func (src *Node) Clone() *Node {
 
 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _NodeCloneNeedsRegeneration = Node(struct {
-	ID                      NodeID
-	StableID                StableNodeID
-	Name                    string
-	User                    UserID
-	Sharer                  UserID
-	Key                     key.NodePublic
-	KeyExpiry               time.Time
-	KeySignature            tkatype.MarshaledSignature
-	Machine                 key.MachinePublic
-	DiscoKey                key.DiscoPublic
-	Addresses               []netip.Prefix
-	AllowedIPs              []netip.Prefix
-	Endpoints               []string
-	DERP                    string
-	Hostinfo                HostinfoView
-	Created                 time.Time
-	Cap                     CapabilityVersion
-	Tags                    []string
-	PrimaryRoutes           []netip.Prefix
-	LastSeen                *time.Time
-	Online                  *bool
-	KeepAlive               bool
-	MachineAuthorized       bool
-	Capabilities            []string
-	UnsignedPeerAPIOnly     bool
-	ComputedName            string
-	computedHostIfDifferent string
-	ComputedNameWithHost    string
-	DataPlaneAuditLogID     string
-	Expired                 bool
+	ID                            NodeID
+	StableID                      StableNodeID
+	Name                          string
+	User                          UserID
+	Sharer                        UserID
+	Key                           key.NodePublic
+	KeyExpiry                     time.Time
+	KeySignature                  tkatype.MarshaledSignature
+	Machine                       key.MachinePublic
+	DiscoKey                      key.DiscoPublic
+	Addresses                     []netip.Prefix
+	AllowedIPs                    []netip.Prefix
+	Endpoints                     []string
+	DERP                          string
+	Hostinfo                      HostinfoView
+	Created                       time.Time
+	Cap                           CapabilityVersion
+	Tags                          []string
+	PrimaryRoutes                 []netip.Prefix
+	LastSeen                      *time.Time
+	Online                        *bool
+	KeepAlive                     bool
+	MachineAuthorized             bool
+	Capabilities                  []string
+	UnsignedPeerAPIOnly           bool
+	ComputedName                  string
+	computedHostIfDifferent       string
+	ComputedNameWithHost          string
+	DataPlaneAuditLogID           string
+	Expired                       bool
+	SelfNodeV4MasqAddrForThisPeer netip.Addr
 }{})
 
 // Clone makes a deep copy of Hostinfo.

tailcfg/tailcfg_view.go

@@ -176,40 +176,44 @@ func (v NodeView) ComputedName() string              { return v.ж.ComputedName
 func (v NodeView) ComputedNameWithHost() string      { return v.ж.ComputedNameWithHost }
 func (v NodeView) DataPlaneAuditLogID() string       { return v.ж.DataPlaneAuditLogID }
 func (v NodeView) Expired() bool                     { return v.ж.Expired }
-func (v NodeView) Equal(v2 NodeView) bool            { return v.ж.Equal(v2.ж) }
+func (v NodeView) SelfNodeV4MasqAddrForThisPeer() netip.Addr {
+	return v.ж.SelfNodeV4MasqAddrForThisPeer
+}
+func (v NodeView) Equal(v2 NodeView) bool { return v.ж.Equal(v2.ж) }
 
 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _NodeViewNeedsRegeneration = Node(struct {
-	ID                      NodeID
-	StableID                StableNodeID
-	Name                    string
-	User                    UserID
-	Sharer                  UserID
-	Key                     key.NodePublic
-	KeyExpiry               time.Time
-	KeySignature            tkatype.MarshaledSignature
-	Machine                 key.MachinePublic
-	DiscoKey                key.DiscoPublic
-	Addresses               []netip.Prefix
-	AllowedIPs              []netip.Prefix
-	Endpoints               []string
-	DERP                    string
-	Hostinfo                HostinfoView
-	Created                 time.Time
-	Cap                     CapabilityVersion
-	Tags                    []string
-	PrimaryRoutes           []netip.Prefix
-	LastSeen                *time.Time
-	Online                  *bool
-	KeepAlive               bool
-	MachineAuthorized       bool
-	Capabilities            []string
-	UnsignedPeerAPIOnly     bool
-	ComputedName            string
-	computedHostIfDifferent string
-	ComputedNameWithHost    string
-	DataPlaneAuditLogID     string
-	Expired                 bool
+	ID                            NodeID
+	StableID                      StableNodeID
+	Name                          string
+	User                          UserID
+	Sharer                        UserID
+	Key                           key.NodePublic
+	KeyExpiry                     time.Time
+	KeySignature                  tkatype.MarshaledSignature
+	Machine                       key.MachinePublic
+	DiscoKey                      key.DiscoPublic
+	Addresses                     []netip.Prefix
+	AllowedIPs                    []netip.Prefix
+	Endpoints                     []string
+	DERP                          string
+	Hostinfo                      HostinfoView
+	Created                       time.Time
+	Cap                           CapabilityVersion
+	Tags                          []string
+	PrimaryRoutes                 []netip.Prefix
+	LastSeen                      *time.Time
+	Online                        *bool
+	KeepAlive                     bool
+	MachineAuthorized             bool
+	Capabilities                  []string
+	UnsignedPeerAPIOnly           bool
+	ComputedName                  string
+	computedHostIfDifferent       string
+	ComputedNameWithHost          string
+	DataPlaneAuditLogID           string
+	Expired                       bool
+	SelfNodeV4MasqAddrForThisPeer netip.Addr
 }{})
 
 // View returns a readonly view of Hostinfo.