1 files changed, 134 insertions, 0 deletions
diff --git a/tests/config/test_dns_generators.lua b/tests/config/test_dns_generators.lua
new file mode 100644
index 0000000..4a7cc0a
--- /dev/null
+++ b/tests/config/test_dns_generators.lua
@@ -0,0 +1,134 @@
+-- SPDX-License-Identifier: GPL-3.0-or-later
+local ffi = require('ffi')
+local kr_cach = kres.context().cache
+
+
+local charset = {
+	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
+	'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
+	'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-'}
+
+local function gen_bytes(len)
+	local bytes = {}
+	for _ = 1,len do
+		table.insert(bytes, charset[math.random(1, #charset)])
+	end
+	local result = table.concat(bytes)
+	assert(#result == len)
+	return result
+end
+
+local function gen_ttl()
+	return math.random(0, 2^31-1)
+end
+
+local function gen_rrtype()
+	return math.random(1024, 61000)
+end
+
+local function gen_rdata(len)
+	assert(len >= 1 and len <= 65535)
+	return gen_bytes(len)
+end
+
+local function gen_label(len)  -- in bytes including the length byte
+	assert(len >= 2 and len <= 64)
+	local bytes = {string.char(len - 1), gen_bytes(len - 1)}
+	return table.concat(bytes)
+end
+
+local function gen_dname()
+	local target_len  -- length 2 bytes does not make sense
+	while target_len == nil or target_len == 2 do
+		target_len = math.random(1, 255)
+	end
+
+	local labels = {string.char(0)}
+	local cur_len = 1
+	while target_len > cur_len do
+		local new_len = math.random(
+					2,
+					math.min(target_len - cur_len,
+						64))
+		if (target_len - cur_len - new_len) == 1 then
+			-- it is a trap, single-byte label is allowed only at the end
+			-- we cannot leave room for single-byte label in the next round
+			if new_len == 64 then
+				goto continue  -- we are at max label length, try again
+			end
+			new_len = new_len + 1
+		end
+		table.insert(labels, 1, gen_label(new_len))
+		cur_len = cur_len + new_len
+		::continue::
+	end
+	assert(target_len == cur_len)
+	local dname = table.concat(labels)
+	assert(#dname >= 1 and #dname <= 255)
+	assert(string.byte(dname, #dname) == 0)
+	return dname
+end
+
+
+local function gen_rrset()
+	local rrs = {}
+	local maxsize = 300  -- RR data size in bytes per RR set, does not include owner etc.
+	local target_len = math.random(1, maxsize)
+	local cur_len = 0
+	while target_len > cur_len do
+		local new_len = math.random(1, target_len - cur_len)
+		local new_rr = gen_rdata(new_len)
+		cur_len = cur_len + #new_rr
+		table.insert(rrs, new_rr)
+	end
+	assert(target_len == cur_len)
+	return rrs, cur_len
+end
+
+
+local function add_random_rrset()
+	local owner = gen_dname()
+	local ttl = gen_ttl()
+	local rr_type = gen_rrtype()
+	local rdata_set = gen_rrset()
+
+	local kr_rrset = kres.rrset(owner, rr_type, kres.class.IN, ttl)
+	for _, rr in ipairs(rdata_set) do
+		assert(kr_rrset:add_rdata(rr, #rr))
+	end
+	assert(kr_cach:insert(kr_rrset, nil, ffi.C.KR_RANK_SECURE))
+end
+
+ffi.cdef('int usleep(uint32_t usec);') -- at least in current glibc it's always 32-bit
+
+local rr_count = 0
+local function gen_batch()
+	for _ = 1,math.random(1,10) do
+		add_random_rrset()
+		rr_count = rr_count + 1
+		if rr_count % 100 == 0 then
+			print('cache usage ', cache.stats()['usage_percent'], '%')
+		end
+	end
+	kr_cach:commit()
+	ffi.C.usleep(15) -- stop *whole process* to give better chance to GC executing
+	local delay
+	if math.random(1,4) == 1 then
+		delay = 1  -- give a chance to DNS resolving
+	else
+		delay = 0
+	end
+	event.after(delay, gen_batch)
+end
+
+return {
+	add_random_rrset=add_random_rrset,
+	gen_batch=gen_batch,
+	gen_bytes=gen_bytes,
+	gen_dname=gen_dname,
+	gen_label=gen_label,
+	gen_rdata=gen_rdata,
+	gen_rrset=gen_rrset,
+	gen_rrtype=gen_rrtype,
+	gen_ttl=gen_ttl
+}