RTMGETADDR

RTMGETADDR is a term that appears in some routing and network management contexts to denote a request or message used to retrieve addressing information associated with routes or interfaces. It is not a universally standardized command across all operating systems, but rather a descriptor that can be found in vendor-specific APIs, routing sockets, or codebases that implement a GETADDR-style operation.

In systems that implement BSD-style routing sockets or similar architectures, RTMGETADDR (or a closely related RTM_GETADDR macro) is used to ask the kernel or a routing daemon for the set of addresses tied to a routing entry. These addresses can include the destination (RTAX_DST), gateway, netmask, broadcast or genmask, and other auxiliary addresses. The request typically specifies which addresses are of interest, and the response returns the corresponding address blocks.

A typical usage pattern involves constructing a routing message with a header that designates the type as a GETADDR-like operation, followed by a bitmask indicating the requested address types. The kernel or daemon then returns a message containing the requested sockaddr structures. This mechanism is commonly employed by system utilities, routing daemons, or debugging tools to inspect current routing state and address bindings.

Because RTMGETADDR is not a universal standard, its exact structure, field names, and behavior vary by platform and API. In Linux, similar functionality is often provided by Netlink interfaces rather than routing sockets. When encountering RTMGETADDR, consulting the specific platform’s routing or netlink documentation is important to understand the precise message format and semantics.

See also: routing sockets, RTM_GET, RTM_ADD, RTM_DELETE, sockaddr, Netlink.