Add ALPN support based on PR #64 from xnyhps

samples/alpn/client.lua

@@ -0,0 +1,27 @@
+--
+-- Public domain
+--
+local socket = require("socket")
+local ssl    = require("ssl")
+
+local params = {
+   mode = "client",
+   protocol = "tlsv1_2",
+   key = "../certs/clientAkey.pem",
+   certificate = "../certs/clientA.pem",
+   cafile = "../certs/rootA.pem",
+   verify = {"peer", "fail_if_no_peer_cert"},
+   options = "all",
+   --alpn = {"foo","bar","baz"}
+   alpn = "foo"
+}
+
+local peer = socket.tcp()
+peer:connect("127.0.0.1", 8888)
+
+peer = assert( ssl.wrap(peer, params) )
+assert(peer:dohandshake())
+
+print("ALPN", peer:getalpn())
+
+peer:close()

samples/alpn/server.lua

@@ -0,0 +1,77 @@
+--
+-- Public domain
+--
+local socket = require("socket")
+local ssl    = require("ssl")
+
+--
+-- Callback that selects one protocol from client's list.
+--
+local function alpncb01(protocols)
+   print("--- ALPN protocols from client")
+   for k, v in ipairs(protocols) do
+      print(k, v)
+   end
+   print("--- Selecting:", protocols[1])
+   return protocols[1]
+end
+
+--
+-- Callback that returns a fixed list, ignoring the client's list.
+--
+local function alpncb02(protocols)
+   print("--- ALPN protocols from client")
+   for k, v in ipairs(protocols) do
+      print(k, v)
+   end
+   print("--- Returning a fixed list") 
+   return {"bar", "foo"}
+end
+
+--
+-- Callback that generates a list as it whishes.
+--
+local function alpncb03(protocols)
+   local resp = {}
+   print("--- ALPN protocols from client")
+   for k, v in ipairs(protocols) do
+      print(k, v)
+      if k%2 ~= 0 then resp[#resp+1] = v end
+   end
+   print("--- Returning an odd list")
+   return resp
+end
+
+
+local params = {
+   mode = "server",
+   protocol = "any",
+   key = "../certs/serverAkey.pem",
+   certificate = "../certs/serverA.pem",
+   cafile = "../certs/rootA.pem",
+   verify = {"peer", "fail_if_no_peer_cert"},
+   options = "all",
+   --alpn = alpncb01,
+   --alpn = alpncb02,
+   --alpn = alpncb03,
+   alpn = {"bar", "baz", "foo"},
+}
+
+
+-- [[ SSL context
+local ctx = assert(ssl.newcontext(params))
+--]]
+
+local server = socket.tcp()
+server:setoption('reuseaddr', true)
+assert( server:bind("127.0.0.1", 8888) )
+server:listen()
+
+local peer = server:accept()
+peer = assert( ssl.wrap(peer, ctx) )
+assert( peer:dohandshake() )
+
+print("ALPN", peer:getalpn())
+
+peer:close()
+server:close()