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util/rfc6724.lua @ 7057:c633e1338554
util.uuid: Use /dev/urandom
author | Kim Alvefur <zash@zash.se> |
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date | Wed, 06 Jan 2016 02:46:47 +0100 |
parent | 5552:40e7a6cf15ff |
child | 7259:d8300985f2bb |
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-- Prosody IM -- Copyright (C) 2011-2013 Florian Zeitz -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- -- This is used to sort destination addresses by preference -- during S2S connections. -- We can't hand this off to getaddrinfo, since it blocks local ip_commonPrefixLength = require"util.ip".commonPrefixLength local new_ip = require"util.ip".new_ip; local function commonPrefixLength(ipA, ipB) local len = ip_commonPrefixLength(ipA, ipB); return len < 64 and len or 64; end local function t_sort(t, comp) for i = 1, (#t - 1) do for j = (i + 1), #t do local a, b = t[i], t[j]; if not comp(a,b) then t[i], t[j] = b, a; end end end end local function source(dest, candidates) local function comp(ipA, ipB) -- Rule 1: Prefer same address if dest == ipA then return true; elseif dest == ipB then return false; end -- Rule 2: Prefer appropriate scope if ipA.scope < ipB.scope then if ipA.scope < dest.scope then return false; else return true; end elseif ipA.scope > ipB.scope then if ipB.scope < dest.scope then return true; else return false; end end -- Rule 3: Avoid deprecated addresses -- XXX: No way to determine this -- Rule 4: Prefer home addresses -- XXX: Mobility Address related, no way to determine this -- Rule 5: Prefer outgoing interface -- XXX: Interface to address relation. No way to determine this -- Rule 6: Prefer matching label if ipA.label == dest.label and ipB.label ~= dest.label then return true; elseif ipB.label == dest.label and ipA.label ~= dest.label then return false; end -- Rule 7: Prefer temporary addresses (over public ones) -- XXX: No way to determine this -- Rule 8: Use longest matching prefix if commonPrefixLength(ipA, dest) > commonPrefixLength(ipB, dest) then return true; else return false; end end t_sort(candidates, comp); return candidates[1]; end local function destination(candidates, sources) local sourceAddrs = {}; local function comp(ipA, ipB) local ipAsource = sourceAddrs[ipA]; local ipBsource = sourceAddrs[ipB]; -- Rule 1: Avoid unusable destinations -- XXX: No such information -- Rule 2: Prefer matching scope if ipA.scope == ipAsource.scope and ipB.scope ~= ipBsource.scope then return true; elseif ipA.scope ~= ipAsource.scope and ipB.scope == ipBsource.scope then return false; end -- Rule 3: Avoid deprecated addresses -- XXX: No way to determine this -- Rule 4: Prefer home addresses -- XXX: Mobility Address related, no way to determine this -- Rule 5: Prefer matching label if ipAsource.label == ipA.label and ipBsource.label ~= ipB.label then return true; elseif ipBsource.label == ipB.label and ipAsource.label ~= ipA.label then return false; end -- Rule 6: Prefer higher precedence if ipA.precedence > ipB.precedence then return true; elseif ipA.precedence < ipB.precedence then return false; end -- Rule 7: Prefer native transport -- XXX: No way to determine this -- Rule 8: Prefer smaller scope if ipA.scope < ipB.scope then return true; elseif ipA.scope > ipB.scope then return false; end -- Rule 9: Use longest matching prefix if commonPrefixLength(ipA, ipAsource) > commonPrefixLength(ipB, ipBsource) then return true; elseif commonPrefixLength(ipA, ipAsource) < commonPrefixLength(ipB, ipBsource) then return false; end -- Rule 10: Otherwise, leave order unchanged return true; end for _, ip in ipairs(candidates) do sourceAddrs[ip] = source(ip, sources); end t_sort(candidates, comp); return candidates; end return {source = source, destination = destination};