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Message-ID: <20250515231650.1325372-8-kuba@kernel.org>
Date: Thu, 15 May 2025 16:16:48 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
andrew+netdev@...n.ch,
horms@...nel.org,
donald.hunter@...il.com,
daniel@...earbox.net,
nicolas.dichtel@...nd.com,
jacob.e.keller@...el.com,
Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net-next 7/9] tools: ynl: submsg: reverse parse / error reporting
Reverse parsing lets YNL convert bad and missing attr pointers
from extack into a string like "missing attribute nest1.nest2.attr_name".
It's a feature that's unique to YNL C AFAIU (even the Python YNL
can't do nested reverse parsing). Add support for reverse-parsing
of sub-messages.
To simplify the logic and the code annotate the type policies
with extra metadata. Mark the selectors and the messages with
the information we need. We assume that key / selector always
precedes the sub-message while parsing (and also if there are
multiple sub-messages like in rt-link they are interleaved
selector 1 ... submsg 1 ... selector 2 .. submsg 2, not
selector 1 ... selector 2 ... submsg 1 ... submsg 2).
The rt-link sample in a subsequent changes shows reverse parsing
of sub-messages in action.
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
tools/net/ynl/lib/ynl-priv.h | 5 +-
tools/net/ynl/lib/ynl.c | 84 ++++++++++++++++++++++++++++----
tools/net/ynl/pyynl/ynl_gen_c.py | 29 ++++++++++-
3 files changed, 107 insertions(+), 11 deletions(-)
diff --git a/tools/net/ynl/lib/ynl-priv.h b/tools/net/ynl/lib/ynl-priv.h
index fbc058dd1c3e..416866f85820 100644
--- a/tools/net/ynl/lib/ynl-priv.h
+++ b/tools/net/ynl/lib/ynl-priv.h
@@ -43,7 +43,10 @@ typedef int (*ynl_parse_cb_t)(const struct nlmsghdr *nlh,
struct ynl_parse_arg *yarg);
struct ynl_policy_attr {
- enum ynl_policy_type type;
+ enum ynl_policy_type type:8;
+ __u8 is_submsg:1;
+ __u8 is_selector:1;
+ __u16 selector_type;
unsigned int len;
const char *name;
const struct ynl_policy_nest *nest;
diff --git a/tools/net/ynl/lib/ynl.c b/tools/net/ynl/lib/ynl.c
index 25fc6501349b..2a169c3c0797 100644
--- a/tools/net/ynl/lib/ynl.c
+++ b/tools/net/ynl/lib/ynl.c
@@ -45,8 +45,39 @@
#define perr(_ys, _msg) __yerr(&(_ys)->err, errno, _msg)
/* -- Netlink boiler plate */
+static bool
+ynl_err_walk_is_sel(const struct ynl_policy_nest *policy,
+ const struct nlattr *attr)
+{
+ unsigned int type = ynl_attr_type(attr);
+
+ return policy && type <= policy->max_attr &&
+ policy->table[type].is_selector;
+}
+
+static const struct ynl_policy_nest *
+ynl_err_walk_sel_policy(const struct ynl_policy_attr *policy_attr,
+ const struct nlattr *selector)
+{
+ const struct ynl_policy_nest *policy = policy_attr->nest;
+ const char *sel;
+ unsigned int i;
+
+ if (!policy_attr->is_submsg)
+ return policy;
+
+ sel = ynl_attr_get_str(selector);
+ for (i = 0; i <= policy->max_attr; i++) {
+ if (!strcmp(sel, policy->table[i].name))
+ return policy->table[i].nest;
+ }
+
+ return NULL;
+}
+
static int
-ynl_err_walk_report_one(const struct ynl_policy_nest *policy, unsigned int type,
+ynl_err_walk_report_one(const struct ynl_policy_nest *policy,
+ const struct nlattr *selector, unsigned int type,
char *str, int str_sz, int *n)
{
if (!policy) {
@@ -67,9 +98,34 @@ ynl_err_walk_report_one(const struct ynl_policy_nest *policy, unsigned int type,
return 1;
}
- if (*n < str_sz)
- *n += snprintf(str, str_sz - *n,
- ".%s", policy->table[type].name);
+ if (*n < str_sz) {
+ int sz;
+
+ sz = snprintf(str, str_sz - *n,
+ ".%s", policy->table[type].name);
+ *n += sz;
+ str += sz;
+ }
+
+ if (policy->table[type].is_submsg) {
+ if (!selector) {
+ if (*n < str_sz)
+ *n += snprintf(str, str_sz, "(!selector)");
+ return 1;
+ }
+
+ if (ynl_attr_type(selector) !=
+ policy->table[type].selector_type) {
+ if (*n < str_sz)
+ *n += snprintf(str, str_sz, "(!=selector)");
+ return 1;
+ }
+
+ if (*n < str_sz)
+ *n += snprintf(str, str_sz - *n, "(%s)",
+ ynl_attr_get_str(selector));
+ }
+
return 0;
}
@@ -78,6 +134,8 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
const struct ynl_policy_nest *policy, char *str, int str_sz,
const struct ynl_policy_nest **nest_pol)
{
+ const struct ynl_policy_nest *next_pol;
+ const struct nlattr *selector = NULL;
unsigned int astart_off, aend_off;
const struct nlattr *attr;
unsigned int data_len;
@@ -96,6 +154,10 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
ynl_attr_for_each_payload(start, data_len, attr) {
astart_off = (char *)attr - (char *)start;
aend_off = (char *)ynl_attr_data_end(attr) - (char *)start;
+
+ if (ynl_err_walk_is_sel(policy, attr))
+ selector = attr;
+
if (aend_off <= off)
continue;
@@ -109,16 +171,20 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
type = ynl_attr_type(attr);
- if (ynl_err_walk_report_one(policy, type, str, str_sz, &n))
+ if (ynl_err_walk_report_one(policy, selector, type, str, str_sz, &n))
+ return n;
+
+ next_pol = ynl_err_walk_sel_policy(&policy->table[type], selector);
+ if (!next_pol)
return n;
if (!off) {
if (nest_pol)
- *nest_pol = policy->table[type].nest;
+ *nest_pol = next_pol;
return n;
}
- if (!policy->table[type].nest) {
+ if (!next_pol) {
if (n < str_sz)
n += snprintf(str, str_sz, "!nest");
return n;
@@ -128,7 +194,7 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
start = ynl_attr_data(attr);
end = start + ynl_attr_data_len(attr);
- return n + ynl_err_walk(ys, start, end, off, policy->table[type].nest,
+ return n + ynl_err_walk(ys, start, end, off, next_pol,
&str[n], str_sz - n, nest_pol);
}
@@ -231,7 +297,7 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
}
n2 = 0;
- ynl_err_walk_report_one(nest_pol, type, &miss_attr[n],
+ ynl_err_walk_report_one(nest_pol, NULL, type, &miss_attr[n],
sizeof(miss_attr) - n, &n2);
n += n2;
diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index b6b54d6fa906..1f8cc34ab3f0 100755
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -57,6 +57,8 @@ from lib import SpecSubMessage, SpecSubMessageFormat
self.request = False
self.reply = False
+ self.is_selector = False
+
if 'len' in attr:
self.len = attr['len']
@@ -484,7 +486,10 @@ from lib import SpecSubMessage, SpecSubMessageFormat
ri.cw.p(f"char *{self.c_name};")
def _attr_typol(self):
- return f'.type = YNL_PT_NUL_STR, '
+ typol = f'.type = YNL_PT_NUL_STR, '
+ if self.is_selector:
+ typol += '.is_selector = 1, '
+ return typol
def _attr_policy(self, policy):
if 'exact-len' in self.checks:
@@ -878,6 +883,16 @@ from lib import SpecSubMessage, SpecSubMessageFormat
class TypeSubMessage(TypeNest):
+ def __init__(self, family, attr_set, attr, value):
+ super().__init__(family, attr_set, attr, value)
+
+ self.selector = Selector(attr, attr_set)
+
+ def _attr_typol(self):
+ typol = f'.type = YNL_PT_NEST, .nest = &{self.nested_render_name}_nest, '
+ typol += f'.is_submsg = 1, .selector_type = {self.attr_set[self["selector"]].value} '
+ return typol
+
def _attr_get(self, ri, var):
sel = c_lower(self['selector'])
get_lines = [f'if (!{var}->{sel})',
@@ -890,6 +905,18 @@ from lib import SpecSubMessage, SpecSubMessageFormat
return get_lines, init_lines, None
+class Selector:
+ def __init__(self, msg_attr, attr_set):
+ self.name = msg_attr["selector"]
+
+ if self.name in attr_set:
+ self.attr = attr_set[self.name]
+ self.attr.is_selector = True
+ self._external = False
+ else:
+ raise Exception("Passing selectors from external nests not supported")
+
+
class Struct:
def __init__(self, family, space_name, type_list=None,
inherited=None, submsg=None):
--
2.49.0
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