Re: [PATCH iproute2-next v2 1/3] Add, show, link, remove IOAM namespaces and schemas

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+static void print_schema(struct rtattr *attrs[])
+{
+	__u8 data[IOAM6_MAX_SCHEMA_DATA_LEN + 1];
+	int len;
+
+	print_uint(PRINT_ANY, "schema", "schema %u",
+		   rta_getattr_u32(attrs[IOAM6_ATTR_SC_ID]));
+
+	if (attrs[IOAM6_ATTR_NS_ID])
+		print_uint(PRINT_ANY, "namespace", " [namespace %u]",
+			   rta_getattr_u16(attrs[IOAM6_ATTR_NS_ID]));
+
+	len = RTA_PAYLOAD(attrs[IOAM6_ATTR_SC_DATA]);
+	memcpy(data, RTA_DATA(attrs[IOAM6_ATTR_SC_DATA]), len);
+	data[len] = '\0';
+
+	print_string(PRINT_ANY, "data", ", data \"%s\"", (const char *)data);

The attribute descriptions shows this as binary data, not a string.

Indeed. Maybe should I print it as hex... What do you think is more appropriate
for this?

./tc/em_meta.c has print_binary() but it is not json aware.

devlink has pr_out_binary_value which is close. You could probably take
this one and generalize it.

Right, I'll take a look.

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+int do_ioam6(int argc, char **argv)
+{
+	bool maybe_wide = false;
+
+	if (argc < 1 || matches(*argv, "help") == 0)
+		usage();
+
+	memset(&opts, 0, sizeof(opts));
+
+	if (matches(*argv, "namespace") == 0) {

matches has been shown to be quite frail. Convenient for shorthand
typing commands, but frail in the big picture. We should stop using it -
especially for new commands.

Sure. What do you suggest as an alternative?

full strcmp.

I see. But, in that case, I'm wondering if it wouldn't be better to directly modify "matches" internally so that we keep consistency between modules without changing everything.

Thoughts?