Add a basic support of Linux's ip nexthop equivalent. In this PR, I
specifically focused on implementing a minimal feature to accomplish
IPv4 prefix with IPv6 (link-local) nexthop which is used by various
implementation like FRR to support technique called BGP Unnumbered.
The summary of the new features are:
- Introduce a low level primitive for nexthop in the nl package
- Introduce NexthopAdd/Del/List/Replace APIs (supports
NHA_ID/BLACKHOLE/GATEWAY, and protocol field)
- Introduce NHID field to the Route object which allows attaching
nexthop to routes.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
=== Squashed Commits ===
nl: Fix some wrong error and done message handling
The current logic of parsing ERROR and DONE message is, first reads
error field and when NLM_F_ACK_TLVS exists, tries to read the original
request header, payload of the request, and extended ACK.
We have three issues here:
1. The existence of the original request header is not indicated by
NLM_F_ACK_TLVS flag. At least the original request header always
exists.
2. We are missing the check for NLM_F_CAPPED flag. When the flag exists,
the payload of the request doesn't exist. In that case, we shouldn't
try to skip the payload. Otherwise, we may end up with the
out-of-range read.
3. NLMSG_DONE doesn't contain the original request, so we shouldn't
apply original request parsing logic to it.
In this commit, we fix these issues by:
1. We first check the existence of the NLM_F_CAPPED. When it exists,
only skip the original request header. Otherwise, skip the payload as
well. Don't apply this logic to the DONE message.
2. After that, check the existence of the NLM_F_ACK_TLVS. When it
exists, try to read extended ACK for both of DONE and ERROR messages.
Otherwise, don't.
Ref: https://docs.kernel.org/userspace-api/netlink/intro.html#netlink-message-types
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
nexthop: Add a low-level API for the nexthop
Preparation for the support of the nexthop object.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
Add basic operation for nexthop
Add a basic support of the Linux's nexthop object (ip nexthop XXX). This
commit aims to introduce a basic operations (add, list, del) with
minimal attributes. Further features can be added later incrementally.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
nexthop: Support NHA_OIF
It can be used for expressing direct nexthop on specific link.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
nexthop: Support NHA_GATEWAY
It can express an IP nexthop. A unique use case we can accomplish by
this is attaching IPv6 nexthop to the routes with an IPv4 prefix which
we cannot do with the existing `ip route` equivalents.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
nexthop: Support protocol
Allow setting protocol for nexthop.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
route: Support RTA_NHID
Support attaching nexthop object to route object via NHID field.
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
nexthop: Add Replace operation support
Add `ip nexthop replace` equivalent
Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>
Yutaro Hayakawa