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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 00:55:53 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 00:55:53 +0000 |
commit | 3d0386f27ca66379acf50199e1d1298386eeeeb8 (patch) | |
tree | f87bd4a126b3a843858eb447e8fd5893c3ee3882 /modules/http/http_trace.lua | |
parent | Initial commit. (diff) | |
download | knot-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.lua | 109 |
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}, + } +}
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