Routing Table¶

The Routing Table (pkg/routing/table.go) is a per-visor key-value store mapping Route IDs to Routing Rules. It is used by the router to determine how incoming packets should be handled.

Route IDs¶

A Route ID is a uint32 value that uniquely identifies a routing rule within a single visor's table. Route IDs are allocated by the visor itself when the Route Setup Node calls ReserveIDs. Route ID 0 is reserved (invalid).

Routing Rules¶

A routing rule is a variable-length byte slice with a fixed header:

Field	Size	Description
KeepAlive	8 bytes	Duration before the rule expires (nanoseconds)
RuleType	1 byte	0=Consume, 1=Forward, 2=IntermediaryForward
KeyRouteID	4 bytes	The route ID this rule is associated with

Consume Rule¶

Delivers the packet to a local application. Additional fields:

Field	Offset	Size	Description
SrcPK	13	33 bytes	Source visor public key
DstPK	46	33 bytes	Destination visor public key
SrcPort	79	2 bytes	Source routing port
DstPort	81	2 bytes	Destination routing port

Forward Rule¶

Forwards the packet to the next hop. Additional fields:

Fields appear in this order on the wire — the route descriptor comes first, then the next-hop fields. Offsets are from the start of the rule.

Field	Offset	Size	Description
SrcPK	13	33 bytes	Source visor public key
DstPK	46	33 bytes	Destination visor public key
SrcPort	79	2 bytes	Source routing port
DstPort	81	2 bytes	Destination routing port
NextRouteID	83	4 bytes	Route ID on the next hop
NextTransportID	87	16 bytes	UUID of the transport to use

IntermediaryForward Rule¶

Forwards the packet through an intermediary visor. Additional fields:

Field	Offset	Size	Description
NextRouteID	13	4 bytes	Route ID on the next hop
NextTransportID	17	16 bytes	UUID of the transport to use

Intermediary rules do not contain source/destination PKs or ports — the intermediary visor only knows the previous and next hop.

Rule Expiry¶

Each rule has a KeepAlive duration (default 24 hours). The routing table periodically sweeps for expired rules and removes them. Route groups send periodic KeepAlivePacket frames to refresh the rules at each hop.

Rule Operations¶

Operation	Description
`ReserveIDs(n)`	Allocates n unused route IDs (called by RSN during route setup)
`SaveRule(rule)`	Stores a routing rule at its key route ID
`Rule(id)`	Retrieves the rule for a given route ID
`DelRules(ids)`	Removes rules by route ID
`AllRules()`	Returns all rules (for debugging / status display)
`Count()`	Returns the number of active rules