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Add support for IPV6 resolvers

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Manuel Alejandro de Brito Fontes 2019-03-09 21:25:05 -03:00
parent 080bed8e88
commit 6c1a7f1efd
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GPG key ID: 786136016A8BA02A
2 changed files with 42 additions and 19 deletions
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8
rootfs/etc/nginx/lua/test/util/dns_test.lua
View file

@ -19,19 +19,19 @@ describe("resolve", function()
dns_helper.mock_dns_query(nil, "oops!")
assert.are.same({ "example.com" }, dns.resolve("example.com"))
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server: oops!")
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server:\noops!\noops!")
dns_helper.mock_dns_query({ errcode = 1, errstr = "format error" })
assert.are.same({ "example.com" }, dns.resolve("example.com"))
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "server returned error code: 1: format error")
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server:\nserver returned error code: 1: format error\nserver returned error code: 1: format error")
dns_helper.mock_dns_query({})
assert.are.same({ "example.com" }, dns.resolve("example.com"))
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "no A record resolved")
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server:\nno record resolved\nno record resolved")
dns_helper.mock_dns_query({ { name = "example.com", cname = "sub.example.com", ttl = 60 } })
assert.are.same({ "example.com" }, dns.resolve("example.com"))
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "no A record resolved")
assert.spy(s_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server:\nno record resolved\nno record resolved")
end)
it("resolves all A records of given host, caches them with minimal ttl and returns from cache next time", function()

57
rootfs/etc/nginx/lua/util/dns.lua
View file

@ -28,6 +28,25 @@ local function a_records_and_max_ttl(answers)
return addresses, ttl
end
local function resolve_host(host, r, qtype)
local answers
answers, err = r:query(host, { qtype = qtype }, {})
if not answers then
return nil, -1, tostring(err)
end
if answers.errcode then
return nil, -1, string.format("server returned error code: %s: %s", answers.errcode, answers.errstr)
end
local addresses, ttl = a_records_and_max_ttl(answers)
if #addresses == 0 then
return nil, -1, "no record resolved"
end
return addresses, ttl, nil
end
function _M.resolve(host)
local cached_addresses = cache:get(host)
if cached_addresses then
@ -50,26 +69,30 @@ function _M.resolve(host)
return { host }
end
local answers
answers, err = r:query(host, { qtype = r.TYPE_A }, {})
if not answers then
ngx.log(ngx.ERR, "failed to query the DNS server: " .. tostring(err))
return { host }
end
if answers.errcode then
ngx.log(ngx.ERR, string.format("server returned error code: %s: %s", answers.errcode, answers.errstr))
return { host }
end
local addresses, ttl = a_records_and_max_ttl(answers)
if #addresses == 0 then
ngx.log(ngx.ERR, "no A record resolved")
return { host }
end
local dns_errors = {}
local addresses, ttl
addresses, ttl, err = resolve_host(host, r, r.TYPE_A)
if not addresses then
table.insert(dns_errors, tostring(err))
elseif #addresses > 0 then
cache:set(host, addresses, ttl)
return addresses
end
addresses, ttl, err = resolve_host(host, r, r.TYPE_AAAA)
if not addresses then
table.insert(dns_errors, tostring(err))
elseif #addresses > 0 then
cache:set(host, addresses, ttl)
return addresses
end
if #dns_errors > 0 then
ngx.log(ngx.ERR, "failed to query the DNS server:\n" .. table.concat(dns_errors, "\n"))
end
return { host }
end
return _M