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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 00:55:53 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 00:55:53 +0000
commit3d0386f27ca66379acf50199e1d1298386eeeeb8 (patch)
treef87bd4a126b3a843858eb447e8fd5893c3ee3882 /modules/http/http_trace.lua
parentInitial commit. (diff)
downloadknot-resolver-3d0386f27ca66379acf50199e1d1298386eeeeb8.tar.xz
knot-resolver-3d0386f27ca66379acf50199e1d1298386eeeeb8.zip
Adding upstream version 3.2.1.upstream/3.2.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--modules/http/http_trace.lua109
1 files changed, 109 insertions, 0 deletions
diff --git a/modules/http/http_trace.lua b/modules/http/http_trace.lua
new file mode 100644
index 0000000..9e4d466
--- /dev/null
+++ b/modules/http/http_trace.lua
@@ -0,0 +1,109 @@
+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.tostring.rank[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')
+ local qname, qtype_str = path:match('/trace/([^/]+)/?([^/]*)')
+ if not qname then
+ return 400, 'expected /trace/<query name>/<query type>'
+ end
+
+ -- Parse query type (or default to A)
+ if not qtype_str or #qtype_str == 0 then
+ qtype_str = 'A'
+ end
+
+ local qtype = kres.type[qtype_str]
+ if not qtype then
+ return 400, string.format('unexpected query type: %s', qtype_str)
+ end
+
+ -- Create logging handler callback
+ local buffer = {}
+ local buffer_log_cb = ffi.cast('trace_log_f', function (query, source, msg)
+ local message = string.format('[%5s] [%s] %s',
+ query.id, ffi.string(source), ffi.string(msg))
+ table.insert(buffer, message)
+ end)
+
+ -- Wait for the result of the query
+ -- Note: We can't do non-blocking write to stream directly from resolve callbacks
+ -- because they don't run inside cqueue.
+ local answers, authority = {}, {}
+ local cond = condition.new()
+ local waiting, done = false, false
+ local finish_cb = ffi.cast('trace_callback_f', function (req)
+ req = kres.request_t(req)
+ add_selected_records(answers, req.answ_selected)
+ add_selected_records(authority, req.auth_selected)
+ if waiting then
+ cond:signal()
+ end
+ done = true
+ end)
+
+ -- Resolve query and buffer logs into table
+ resolve {
+ name = qname,
+ type = qtype,
+ options = {'TRACE'},
+ init = function (req)
+ req = kres.request_t(req)
+ req.trace_log = buffer_log_cb
+ req.trace_finish = finish_cb
+ end
+ }
+
+ -- Wait for asynchronous query and free callbacks
+ if not done then
+ waiting = true
+ cond:wait()
+ end
+
+ buffer_log_cb:free()
+ finish_cb:free()
+
+ -- 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
+ return result
+end
+
+-- Export endpoints
+return {
+ endpoints = {
+ ['/trace'] = {'text/plain', serve_trace},
+ }
+} \ No newline at end of file