routesocket

RouteSocket refers to a Windows socket type used to send and receive routing table information, or alternatively, to an API on BSD and Linux systems for the manipulation of routing tables. The concept was introduced to provide an interface for applications to query and configure routing entries without requiring privileged system calls. Historically, the route socket has been part of the BSD networking stack, offering an object‐oriented approach to socket creation. Certain operating systems, particularly FreeBSD and NetBSD, expose a route socket through the AF_ROUTE domain. Linux, however, implements a similar interface but typically relies on the NETLINK mechanism for routing.

When an application opens a route socket, it typically binds to the AF_ROUTE address family and then sends messages containing commands such as SYSCTL, RTA_TABLE, and RTA_FAMILY. These messages are parsed by the kernel and translated into updates to the kernel’s forwarding tables. The interface supports operations like adding and deleting routes, retrieving the current routing table, and listening for changes through subscription messages. The route socket API is generally split into two layers: a low‑level socket API that deals with raw structures, and a higher‑level library such as libnet or libroute that abstracts many details.

Because the route socket interface allows direct access to routing tables, it is normally restricted to privileged users or processes that possess appropriate capabilities. On some systems, a dedicated daemon such as rc.local or dhclient may use the socket to adjust routing tables in response to network events. Scripting languages can access the route socket via bindings to the socket library, enabling dynamic network configuration.

RouteSocket usage is common in network monitoring tools, firewall configuration utilities, and routing daemons. It provides a direct, low‑overhead method to interact with kernel routing information, in contrast to higher level protocols such as SNMP or HTTP APIs.