expand synth to generate random payloads and include a packet id, add…

… apps.test.npackets an app that only sends n packets from input to output

src/apps/test/README.md

@@ -69,3 +69,29 @@ Source and destination MAC addresses in human readable from. The default is
 
 An array of numbers designating the packet payload sizes. The default is
 `{64}`.
+
+— Key **random_payload**
+Generate a random payload for each packet in `sizes`
+
+— Key **packet_id**
+Insert the packet number (32bit uint) directly after the ethertype. The packet
+number starts at 0 and is sequential on each output link.
+
+## Npackets (apps.test.npackets)
+
+The `Npackets` app allows are most N packets to flow through it. Any further
+packets are never dequeued from input.
+
+    DIAGRAM: Npackets
+    		+-----------+
+input ->     	| Npackets  | -> output
+    		+-----------+
+
+### Configuration
+
+The `Npackets` app accepts a table as its configuration argument. The following
+keys are defined:
+
+— Key **npackets**
+The number of packets to forward, further packets are never dequeued from
+input.

src/apps/test/npackets.lua

@@ -0,0 +1,41 @@
+module(...,package.seeall)
+
+local ffi = require("ffi")
+local C = ffi.C
+Npackets = {
+   config = {
+      npackets = { default = 1000000 }
+   }
+}
+
+function Npackets:new (conf)
+   return setmetatable({n = conf.npackets}, { __index = Npackets})
+end
+
+function Npackets:push ()
+   while not link.empty(self.input.input) and
+      self.n > 0 do
+      link.transmit(self.output.output, link.receive(self.input.input))
+      self.n = self.n - 1
+   end
+end
+
+function selftest()
+   local synth = require("apps.test.synth")
+   local basic_apps = require("apps.basic.basic_apps")
+   local counter = require("core.counter")
+
+   local c = config.new()
+   config.app(c, "src", synth.Synth)
+   config.app(c, "n", Npackets, { npackets = 100 })
+   config.app(c, "sink", basic_apps.Sink)
+   config.link(c, "src.output -> n.input")
+   config.link(c, "n.output -> sink.input")
+   engine.configure(c)
+   assert(engine.app_table.n.n == 100)
+   engine.main({duration=1})
+   assert(engine.app_table.n.n == 0)
+   assert(counter.read(engine.link_table['src.output -> n.input'].stats.txpackets) > 100)
+   local cnt = counter.read(engine.link_table['n.output -> sink.input'].stats.rxpackets)
+   assert(100 == cnt)
+end

src/apps/test/synth.lua

@@ -12,6 +12,8 @@ Synth = {
       sizes = {default={64}},
       src = {default='00:00:00:00:00:00'},
       dst = {default='00:00:00:00:00:00'},
+      random_payload = { default = false },
+      packet_id = { default = false },
    }
 }
 
@@ -23,6 +25,14 @@ function Synth:new (conf)
       assert(payload_size >= 0 and payload_size <= 1536,
              "Invalid payload size: "..payload_size)
       local data = ffi.new("char[?]", payload_size)
+      if conf.random_payload then
+         -- dstmac + srcmac + type
+         local off = 6 + 6 + 2
+         ffi.fill(data, payload_size)
+         ffi.copy(data + off,
+            lib.random_bytes(payload_size - off), payload_size - off)
+      end
+
       local dgram = datagram:new(packet.from_pointer(data, payload_size))
       local ether = ethernet:new({ src = ethernet:pton(conf.src),
 				   dst = ethernet:pton(conf.dst),
@@ -38,7 +48,13 @@ function Synth:pull ()
       local n = 0
       while n < engine.pull_npackets do
          for _, p in ipairs(self.packets) do
-	    transmit(o, packet.clone(p))
+            local c = packet.clone(p)
+            if self.packet_id then
+               -- 14 == sizeof(dstmac srcmac type)
+               ffi.cast("uint32_t *", clone.data+14)[0] = lib.htonl(self.pktid)
+               self.pktid = self.pktid + 1
+            end
+	    transmit(o, c)
             n = n + 1
 	 end
       end