modules/http: added selected records to /trace endpoint

This allows debugging of what records were used for final answer.

diff --git a/daemon/lua/kres.lua b/daemon/lua/kres.lua
index ed9fc31c1fb72151d62d22c3251a0184780e1e5e..8972160a87e21baefd14100a176a121d0ea9a99d 100644 (file)
--- a/daemon/lua/kres.lua
+++ b/daemon/lua/kres.lua
@@ -153,6 +153,26 @@ local const_rcode = {
        BADCOOKIE  = 23,
 }
 
+-- This corresponds to `enum kr_rank`, it's not possible to do this without introspection unfortunately
+local const_rank = {
+       INITIAL = 0,
+       OMIT = 1,
+       TRY = 2,
+       INDET = 4,
+       BOGUS = 5,
+       MISMATCH = 6,
+       MISSING = 7,
+       INSECURE = 8,
+       AUTH = 16,
+       SECURE = 32
+}
+
+-- Create inverse table
+local const_rank_tostring = {}
+for k, v in pairs(const_rank) do
+       const_rank_tostring[v] = k
+end
+
 -- Metatype for RR types to allow anonymous types
 setmetatable(const_type, {
        __index = function (t, k)
@@ -185,6 +205,7 @@ local knot_rrset_t = ffi.typeof('knot_rrset_t')
 ffi.metatype( knot_rrset_t, {
        -- beware: `owner` and `rdata` are typed as a plain lua strings
        --         and not the real types they represent.
+       __tostring = function(rr) return rr:txt_dump() end,
        __index = {
                owner = function(rr) return ffi.string(rr._owner, knot.knot_dname_size(rr._owner)) end,
                ttl = function(rr) return tonumber(knot.knot_rrset_ttl(rr)) end,
@@ -319,6 +340,30 @@ ffi.metatype( kr_request_t, {
        },
 })
 
+-- C array iterator
+local function c_array_iter(t, i)
+       i = i + 1
+       if i >= t.len then return end
+       return i, t.at[i][0]
+end
+
+-- Metatype for ranked record array
+local ranked_rr_array_t = ffi.typeof('ranked_rr_array_t')
+ffi.metatype(ranked_rr_array_t, {
+       __len = function(self)
+               return tonumber(self.len)
+       end,
+       __ipairs = function (self)
+               return c_array_iter, self, -1
+       end,
+       __index = {
+               get = function (self, i)
+                       if i < 0 or i > self.len then return nil end
+                       return self.at[i][0]
+               end,
+       }
+})
+
 -- Pretty print for domain name
 local function dname2str(dname)
        return ffi.string(ffi.gc(C.knot_dname_to_str(nil, dname, 0), C.free))
@@ -357,6 +402,8 @@ kres = {
        type = const_type,
        section = const_section,
        rcode = const_rcode,
+       rank = const_rank,
+       rank_tostring = const_rank_tostring,
 
        -- Create a struct kr_qflags from a single flag name or a list of names.
        mk_qflags = function (names)

diff --git a/modules/http/http_trace.lua b/modules/http/http_trace.lua
index c09973a0f645ef2ecbbb63ae40219f7ba2f198e1..d4827bd63b10308279af3302dd43e512976fe836 100644 (file)
--- a/modules/http/http_trace.lua
+++ b/modules/http/http_trace.lua
@@ -1,6 +1,32 @@
 local ffi = require('ffi')
+local bit = require('bit')
 local condition = require('cqueues.condition')
 
+-- Buffer selected record information to a table
+local function add_selected_records(dst, records)
+       for _, rec in ipairs(records) do
+               local rank = rec.rank
+               -- Separate the referral chain verified flag
+               local verified = bit.band(rec.rank, kres.rank.AUTH)
+               if verified then
+                       rank = bit.band(rank, bit.bnot(kres.rank.AUTH))
+               end
+               local rank_name = kres.rank_tostring[rank] or tostring(rank)
+               -- Write out each individual RR
+               for rr in tostring(rec.rr):gmatch('[^\n]+\n?') do
+                       local row = string.format('cached: %s, rank: %s, record: %s',
+                               rec.cached, rank_name:lower(), rr)
+                       table.insert(dst, row)
+               end
+       end
+end
+
+local function format_selected_records(header, records)
+       if #records == 0 then return '' end
+       return string.format('%s\n%s\n', header, string.rep('-', #header))
+              .. table.concat(records, '') .. '\n'
+end
+
 -- Trace execution of DNS queries
 local function serve_trace(h, _)
        local path = h:get(':path')
@@ -34,6 +60,7 @@ local function serve_trace(h, _)
        local done = false
 
        -- Resolve query and buffer logs into table
+       local answers, authority = {}, {}
        resolve {
                name = qname,
                type = qtype,
@@ -42,7 +69,10 @@ local function serve_trace(h, _)
                        req = kres.request_t(req)
                        req.trace_log = buffer_log_cb
                end,
-               finish = function ()
+               finish = function (_, req)
+                       req = kres.request_t(req)
+                       add_selected_records(answers, req.answ_selected)
+                       add_selected_records(authority, req.auth_selected)
                        cond:signal()
                        done = true
                end
@@ -56,8 +86,11 @@ local function serve_trace(h, _)
        end
        buffer_log_cb:free()
 
-       -- Return buffered data
+       -- Build the result
        local result = table.concat(buffer, '') .. '\n'
+                      .. format_selected_records('Used records from answer:', answers)
+                      .. format_selected_records('Used records from authority:', authority)
+       -- Return buffered data
        if not done then
                return 504, result
        end