1 -- Prosody IM |
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2 -- Copyright (C) 2008-2011 Florian Zeitz |
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3 -- |
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4 -- This project is MIT/X11 licensed. Please see the |
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5 -- COPYING file in the source package for more information. |
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6 -- |
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7 |
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8 local commonPrefixLength = require"util.ip".commonPrefixLength |
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9 local new_ip = require"util.ip".new_ip; |
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10 |
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11 local function t_sort(t, comp) |
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12 for i = 1, (#t - 1) do |
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13 for j = (i + 1), #t do |
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14 local a, b = t[i], t[j]; |
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15 if not comp(a,b) then |
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16 t[i], t[j] = b, a; |
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17 end |
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18 end |
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19 end |
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20 end |
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21 |
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22 local function source(dest, candidates) |
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23 local function comp(ipA, ipB) |
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24 -- Rule 1: Prefer same address |
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25 if dest == ipA then |
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26 return true; |
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27 elseif dest == ipB then |
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28 return false; |
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29 end |
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30 |
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31 -- Rule 2: Prefer appropriate scope |
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32 if ipA.scope < ipB.scope then |
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33 if ipA.scope < dest.scope then |
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34 return false; |
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35 else |
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36 return true; |
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37 end |
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38 elseif ipA.scope > ipB.scope then |
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39 if ipB.scope < dest.scope then |
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40 return true; |
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41 else |
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42 return false; |
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43 end |
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44 end |
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45 |
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46 -- Rule 3: Avoid deprecated addresses |
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47 -- XXX: No way to determine this |
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48 -- Rule 4: Prefer home addresses |
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49 -- XXX: Mobility Address related, no way to determine this |
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50 -- Rule 5: Prefer outgoing interface |
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51 -- XXX: Interface to address relation. No way to determine this |
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52 -- Rule 6: Prefer matching label |
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53 if ipA.label == dest.label and ipB.label ~= dest.label then |
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54 return true; |
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55 elseif ipB.label == dest.label and ipA.label ~= dest.label then |
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56 return false; |
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57 end |
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58 |
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59 -- Rule 7: Prefer public addresses (over temporary ones) |
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60 -- XXX: No way to determine this |
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61 -- Rule 8: Use longest matching prefix |
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62 if commonPrefixLength(ipA, dest) > commonPrefixLength(ipB, dest) then |
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63 return true; |
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64 else |
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65 return false; |
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66 end |
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67 end |
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68 |
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69 t_sort(candidates, comp); |
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70 return candidates[1]; |
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71 end |
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72 |
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73 local function destination(candidates, sources) |
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74 local sourceAddrs = {}; |
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75 local function comp(ipA, ipB) |
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76 local ipAsource = sourceAddrs[ipA]; |
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77 local ipBsource = sourceAddrs[ipB]; |
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78 -- Rule 1: Avoid unusable destinations |
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79 -- XXX: No such information |
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80 -- Rule 2: Prefer matching scope |
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81 if ipA.scope == ipAsource.scope and ipB.scope ~= ipBsource.scope then |
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82 return true; |
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83 elseif ipA.scope ~= ipAsource.scope and ipB.scope == ipBsource.scope then |
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84 return false; |
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85 end |
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86 |
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87 -- Rule 3: Avoid deprecated addresses |
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88 -- XXX: No way to determine this |
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89 -- Rule 4: Prefer home addresses |
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90 -- XXX: Mobility Address related, no way to determine this |
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91 -- Rule 5: Prefer matching label |
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92 if ipAsource.label == ipA.label and ipBsource.label ~= ipB.label then |
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93 return true; |
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94 elseif ipBsource.label == ipB.label and ipAsource.label ~= ipA.label then |
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95 return false; |
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96 end |
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97 |
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98 -- Rule 6: Prefer higher precedence |
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99 if ipA.precedence > ipB.precedence then |
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100 return true; |
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101 elseif ipA.precedence < ipB.precedence then |
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102 return false; |
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103 end |
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104 |
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105 -- Rule 7: Prefer native transport |
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106 -- XXX: No way to determine this |
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107 -- Rule 8: Prefer smaller scope |
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108 if ipA.scope < ipB.scope then |
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109 return true; |
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110 elseif ipA.scope > ipB.scope then |
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111 return false; |
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112 end |
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113 |
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114 -- Rule 9: Use longest matching prefix |
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115 if commonPrefixLength(ipA, ipAsource) > commonPrefixLength(ipB, ipBsource) then |
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116 return true; |
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117 elseif commonPrefixLength(ipA, ipAsource) < commonPrefixLength(ipB, ipBsource) then |
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118 return false; |
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119 end |
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120 |
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121 -- Rule 10: Otherwise, leave order unchanged |
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122 return true; |
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123 end |
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124 for _, ip in ipairs(candidates) do |
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125 sourceAddrs[ip] = source(ip, sources); |
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126 end |
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127 |
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128 t_sort(candidates, comp); |
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129 return candidates; |
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130 end |
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131 |
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132 return {source = source, |
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133 destination = destination}; |
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