1 -- Prosody IM |
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2 -- Copyright (C) 2008-2010 Matthew Wild |
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3 -- Copyright (C) 2008-2010 Waqas Hussain |
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4 -- |
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5 -- This project is MIT/X11 licensed. Please see the |
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6 -- COPYING file in the source package for more information. |
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7 -- |
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8 |
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9 local server = require "net.server"; |
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10 local dns = require "net.dns"; |
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11 |
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12 local log = require "util.logger".init("adns"); |
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13 |
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14 local t_insert, t_remove = table.insert, table.remove; |
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15 local coroutine, tostring, pcall = coroutine, tostring, pcall; |
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16 |
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17 local function dummy_send(sock, data, i, j) return (j-i)+1; end |
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18 |
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19 module "adns" |
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20 |
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21 function lookup(handler, qname, qtype, qclass) |
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22 return coroutine.wrap(function (peek) |
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23 if peek then |
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24 log("debug", "Records for %s already cached, using those...", qname); |
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25 handler(peek); |
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26 return; |
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27 end |
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28 log("debug", "Records for %s not in cache, sending query (%s)...", qname, tostring(coroutine.running())); |
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29 local ok, err = dns.query(qname, qtype, qclass); |
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30 if ok then |
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31 coroutine.yield({ qclass or "IN", qtype or "A", qname, coroutine.running()}); -- Wait for reply |
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32 log("debug", "Reply for %s (%s)", qname, tostring(coroutine.running())); |
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33 end |
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34 if ok then |
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35 ok, err = pcall(handler, dns.peek(qname, qtype, qclass)); |
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36 else |
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37 log("error", "Error sending DNS query: %s", err); |
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38 ok, err = pcall(handler, nil, err); |
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39 end |
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40 if not ok then |
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41 log("error", "Error in DNS response handler: %s", tostring(err)); |
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42 end |
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43 end)(dns.peek(qname, qtype, qclass)); |
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44 end |
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45 |
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46 function cancel(handle, call_handler, reason) |
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47 log("warn", "Cancelling DNS lookup for %s", tostring(handle[3])); |
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48 dns.cancel(handle[1], handle[2], handle[3], handle[4], call_handler); |
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49 end |
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50 |
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51 function new_async_socket(sock, resolver) |
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52 local peername = "<unknown>"; |
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53 local listener = {}; |
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54 local handler = {}; |
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55 local err; |
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56 function listener.onincoming(conn, data) |
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57 if data then |
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58 dns.feed(handler, data); |
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59 end |
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60 end |
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61 function listener.ondisconnect(conn, err) |
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62 if err then |
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63 log("warn", "DNS socket for %s disconnected: %s", peername, err); |
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64 local servers = resolver.server; |
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65 if resolver.socketset[conn] == resolver.best_server and resolver.best_server == #servers then |
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66 log("error", "Exhausted all %d configured DNS servers, next lookup will try %s again", #servers, servers[1]); |
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67 end |
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68 |
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69 resolver:servfail(conn); -- Let the magic commence |
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70 end |
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71 end |
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72 handler, err = server.wrapclient(sock, "dns", 53, listener); |
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73 if not handler then |
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74 return nil, err; |
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75 end |
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76 |
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77 handler.settimeout = function () end |
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78 handler.setsockname = function (_, ...) return sock:setsockname(...); end |
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79 handler.setpeername = function (_, ...) peername = (...); local ret, err = sock:setpeername(...); _:set_send(dummy_send); return ret, err; end |
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80 handler.connect = function (_, ...) return sock:connect(...) end |
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81 --handler.send = function (_, data) _:write(data); return _.sendbuffer and _.sendbuffer(); end |
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82 handler.send = function (_, data) |
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83 log("debug", "Sending DNS query to %s", peername); |
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84 return sock:send(data); |
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85 end |
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86 return handler; |
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87 end |
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88 |
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89 dns.socket_wrapper_set(new_async_socket); |
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90 |
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91 return _M; |
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