Store user-supplied source protocol in the nexthops and nexthop groups.
Protocol specification help routing daemons like bird to quickly
identify self-originated routes after the crash or restart.
Example:
```
10.2.0.0/24 via 10.0.0.2 dev vtnet0 proto bird
10.3.0.0/24 proto bird
nexthop via 10.0.0.2 dev vtnet0 weight 3
nexthop via 10.0.0.3 dev vtnet0 weight 4
```
For some of these Clang produced a warning that "a function declaration
without a prototype is deprecated in all versions of C". In other cases
the function defintion used () which did not match the header
declaration, which used (void).
Sponsored by: The FreeBSD Foundation
By adding missing ifdefs for INET and INET6 when building LINT-NOIP .
Differential Revision: https://reviews.freebsd.org/D36731
Sponsored by: NVIDIA Networking
Netlinks is a communication protocol currently used in Linux kernel to modify,
read and subscribe for nearly all networking state. Interfaces, addresses, routes,
firewall, fibs, vnets, etc are controlled via netlink.
It is async, TLV-based protocol, providing 1-1 and 1-many communications.
The current implementation supports the subset of NETLINK_ROUTE
family. To be more specific, the following is supported:
* Dumps:
- routes
- nexthops / nexthop groups
- interfaces
- interface addresses
- neighbors (arp/ndp)
* Notifications:
- interface arrival/departure
- interface address arrival/departure
- route addition/deletion
* Modifications:
- adding/deleting routes
- adding/deleting nexthops/nexthops groups
- adding/deleting neghbors
- adding/deleting interfaces (basic support only)
* Rtsock interaction
- route events are bridged both ways
The implementation also supports the NETLINK_GENERIC family framework.
Implementation notes:
Netlink is implemented via loadable/unloadable kernel module,
not touching many kernel parts.
Each netlink socket uses dedicated taskqueue to support async operations
that can sleep, such as interface creation. All message processing is
performed within these taskqueues.
Compatibility:
Most of the Netlink data models specified above maps to FreeBSD concepts
nicely. Unmodified ip(8) binary correctly works with
interfaces, addresses, routes, nexthops and nexthop groups. Some
software such as net/bird require header-only modifications to compile
and work with FreeBSD netlink.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D36002
MFC after: 2 months
