kernel/tools/net/ynl/lib/ynl.h, branch linux-rolling-stable

tools: ynl-gen: submsg: support parsing and rendering sub-messages

2025-05-16T23:32:06Z

Adjust parsing and rendering appropriately to make sub-messages work. Rendering is pretty trivial, as the submsg -> netlink conversion looks like rendering a nest in which only one attr was set. Only trick is that we use the enum value of the sub-message rather than the nest as the type, and effectively skip one layer of nesting. A real double nested struct would look like this: [SELECTOR] [SUBMSG] [NEST] [MSG1-ATTR] A submsg "is" the nest so by skipping I mean: [SELECTOR] [SUBMSG] [MSG1-ATTR] There is no extra validation in YNL if caller has set the selector matching the submsg type (e.g. link type = "macvlan" but the nest attrs are set to carry "veth"). Let the kernel handle that. Parsing side is a little more specialized as we need to render and insert a new kind of function which switches between what to parse based on the selector. But code isn't too complicated. Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250515231650.1325372-7-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: allow fixed-header to be specified per op

2025-05-02T10:41:03Z

rtnetlink has variety of ops with different fixed headers. Detect that op fixed header is not the same as family one, and use sizeof() directly. For reverse parsing we need to pass the fixed header len along the policy (in the socket state). Reviewed-by: Donald Hunter Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20250429154704.2613851-13-kuba@kernel.org Signed-off-by: Paolo Abeni

tools: ynl-gen: multi-attr: type gen for string

2025-05-02T10:41:02Z

Add support for multi attr strings (needed for link alt_names). We record the length individual strings in a len member, to do the same for multi-attr create a struct ynl_string in ynl.h and use it as a layer holding both the string and its length. Since strings may be arbitrary length dynamically allocate each individual one. Adjust arg_member and struct member to avoid spacing the double pointers to get "type **name;" rather than "type * *name;" Reviewed-by: Donald Hunter Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20250429154704.2613851-8-kuba@kernel.org Signed-off-by: Paolo Abeni

tools: ynl: support creating non-genl sockets

2025-04-11T03:14:41Z

Classic netlink has static family IDs specified in YAML, there is no family name -> ID lookup. Support providing the ID info to the library via the generated struct and make library use it. Since NETLINK_ROUTE is ID 0 we need an extra boolean to indicate classic_id is to be used. Reviewed-by: Jacob Keller Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250410014658.782120-8-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: make user space policies const

2024-06-09T14:51:40Z

Dan, who's working on C++ YNL, pointed out that the C code does not make policies const. Sprinkle some 'const's around. Reported-by: Dan Melnic Signed-off-by: Jakub Kicinski Reviewed-by: Donald Hunter Reviewed-by: Nicolas Dichtel Signed-off-by: David S. Miller

tools: ynl: add ynl_dump_empty() helper

2024-04-03T01:01:58Z

Checking if dump is empty requires a couple of casts. Add a convenient wrapper. Add an example use in the netdev sample, loopback is always present so an empty dump is an error. Reviewed-by: Nicolas Dichtel Link: https://lore.kernel.org/r/20240329181651.319326-1-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: check for overflow of constructed messages

2024-03-07T19:01:31Z

Donald points out that we don't check for overflows. Stash the length of the message on nlmsg_pid (nlmsg_seq would do as well). This allows the attribute helpers to remain self-contained (no extra arguments). Also let the put helpers continue to return nothing. The error is checked only in (newly introduced) ynl_msg_end(). Reviewed-by: Donald Hunter Link: https://lore.kernel.org/r/20240305185000.964773-1-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: stop using mnl socket helpers

2024-02-28T23:25:44Z

Most libmnl socket helpers can be replaced by direct calls to the underlying libc API. We need portid, the netlink manpage suggests we bind() address of zero. Acked-by: Nicolas Dichtel Link: https://lore.kernel.org/r/20240227223032.1835527-14-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: stop using mnl_cb_run2()

2024-02-28T23:25:44Z

There's only one set of callbacks in YNL, for netlink control messages, and most of them are trivial. So implement the message walking directly without depending on mnl_cb_run2(). Acked-by: Nicolas Dichtel Link: https://lore.kernel.org/r/20240227223032.1835527-11-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl-gen: support fixed headers in genetlink

2023-12-15T01:51:21Z

Support genetlink families using simple fixed headers. Assume fixed header is identical for all ops of the family for now. Fixed headers are added to the request and reply structs as a _hdr member, and copied to/from netlink messages appropriately. Reviewed-by: Donald Hunter Link: https://lore.kernel.org/r/20231213231432.2944749-4-kuba@kernel.org Signed-off-by: Jakub Kicinski