tools: ynl: let classic netlink requests specify extra nlflags

Classic netlink makes extensive use of flags. Support specifying
them the same way as attributes are specified (using a helper),
for example:

     rt_link_newlink_req_set_nlflags(req, NLM_F_CREATE | NLM_F_ECHO);

Wrap the code up in a RenderInfo predicate. I think that some
genetlink families may want this, too. It should be easy to
add a spec property later.

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250429154704.2613851-5-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/tools/net/ynl/lib/ynl-priv.h b/tools/net/ynl/lib/ynl-priv.h
index 634eb16548b93d4ce1f601e2dead8cb5fca73786..5debb09491e7baac564a7824a72ffa7c0325f0aa 100644 (file)
--- a/tools/net/ynl/lib/ynl-priv.h
+++ b/tools/net/ynl/lib/ynl-priv.h
@@ -94,7 +94,7 @@ struct ynl_ntf_base_type {
        unsigned char data[] __attribute__((aligned(8)));
 };
 
-struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id);
+struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id, __u16 flags);
 struct nlmsghdr *ynl_msg_start_dump(struct ynl_sock *ys, __u32 id);
 
 struct nlmsghdr *

diff --git a/tools/net/ynl/lib/ynl.c b/tools/net/ynl/lib/ynl.c
index 70f899a540076928c6fe9d59059d4fc55a6899b5..c16f01372ca32dc916d07384aef7110d706115f7 100644 (file)
--- a/tools/net/ynl/lib/ynl.c
+++ b/tools/net/ynl/lib/ynl.c
@@ -451,9 +451,9 @@ ynl_gemsg_start(struct ynl_sock *ys, __u32 id, __u16 flags,
        return nlh;
 }
 
-struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id)
+struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id, __u16 flags)
 {
-       return ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK);
+       return ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK | flags);
 }
 
 struct nlmsghdr *ynl_msg_start_dump(struct ynl_sock *ys, __u32 id)

diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index 898c41a7a81fe82484eb64b688d2bbe530c93d2a..c035abb8ae1c51724a64447e2952699dcff22eea 100755 (executable)
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -1294,6 +1294,9 @@ class RenderInfo:
     def type_empty(self, key):
         return len(self.struct[key].attr_list) == 0 and self.fixed_hdr is None
 
+    def needs_nlflags(self, direction):
+        return self.op_mode == 'do' and direction == 'request' and self.family.is_classic()
+
 
 class CodeWriter:
     def __init__(self, nlib, out_file=None, overwrite=True):
@@ -1924,7 +1927,7 @@ def print_req(ri):
     ri.cw.write_func_lvar(local_vars)
 
     if ri.family.is_classic():
-        ri.cw.p(f"nlh = ynl_msg_start_req(ys, {ri.op.enum_name});")
+        ri.cw.p(f"nlh = ynl_msg_start_req(ys, {ri.op.enum_name}, req->_nlmsg_flags);")
     else:
         ri.cw.p(f"nlh = ynl_gemsg_start_req(ys, {ri.nl.get_family_id()}, {ri.op.enum_name}, 1);")
 
@@ -2053,6 +2056,16 @@ def print_free_prototype(ri, direction, suffix=';'):
     ri.cw.write_func_prot('void', f"{name}_free", [f"struct {struct_name} *{arg}"], suffix=suffix)
 
 
+def print_nlflags_set(ri, direction):
+    name = op_prefix(ri, direction)
+    ri.cw.write_func_prot(f'static inline void', f"{name}_set_nlflags",
+                          [f"struct {name} *req", "__u16 nl_flags"])
+    ri.cw.block_start()
+    ri.cw.p('req->_nlmsg_flags = nl_flags;')
+    ri.cw.block_end()
+    ri.cw.nl()
+
+
 def _print_type(ri, direction, struct):
     suffix = f'_{ri.type_name}{direction_to_suffix[direction]}'
     if not direction and ri.type_name_conflict:
@@ -2063,6 +2076,9 @@ def _print_type(ri, direction, struct):
 
     ri.cw.block_start(line=f"struct {ri.family.c_name}{suffix}")
 
+    if ri.needs_nlflags(direction):
+        ri.cw.p('__u16 _nlmsg_flags;')
+        ri.cw.nl()
     if ri.fixed_hdr:
         ri.cw.p(ri.fixed_hdr + ' _hdr;')
         ri.cw.nl()
@@ -2102,6 +2118,9 @@ def print_type_helpers(ri, direction, deref=False):
     print_free_prototype(ri, direction)
     ri.cw.nl()
 
+    if ri.needs_nlflags(direction):
+        print_nlflags_set(ri, direction)
+
     if ri.ku_space == 'user' and direction == 'request':
         for _, attr in ri.struct[direction].member_list():
             attr.setter(ri, ri.attr_set, direction, deref=deref)