Add housekeeping() method to apps

Move code not related to processing of packets from the input link to
the new method.

src/apps/ipv4/arp.lua

@@ -221,8 +221,6 @@ function ARP:push()
    local isouth, osouth = self.input.south, self.output.south
    local inorth, onorth = self.input.north, self.output.north
 
-   self:maybe_send_arp_request(osouth)
-
    for _ = 1, link.nreadable(isouth) do
       local p = receive(isouth)
       if p.length < ether_header_len then
@@ -269,6 +267,10 @@ function ARP:push()
    end
 end
 
+function ARP:housekeeping ()
+   self:maybe_send_arp_request(self.output.south)
+end
+
 function selftest()
    print('selftest: arp')
 
@@ -278,8 +280,8 @@ function selftest()
    arp.input  = { south=link.new('south in'),  north=link.new('north in') }
    arp.output = { south=link.new('south out'), north=link.new('north out') }
 
-   -- After first push, ARP should have sent out request.
-   arp:push()
+   -- After first housekeeping, ARP should have sent out request.
+   arp:housekeeping()
    assert(link.nreadable(arp.output.south) == 1)
    assert(link.nreadable(arp.output.north) == 0)
    local req = link.receive(arp.output.south)

src/apps/ipv4/fragment.lua

@@ -170,8 +170,6 @@ function Fragmenter:push ()
    local input, output = self.input.input, self.output.output
    local max_length = self.mtu + ether_header_len
 
-   self.outgoing_ipv4_fragments_alarm:check()
-
    for _ = 1, link.nreadable(input) do
       local pkt = link.receive(input)
       local h = ffi.cast(ether_ipv4_header_ptr_t, pkt.data)
@@ -196,6 +194,10 @@ function Fragmenter:push ()
    end
 end
 
+function Fragmenter:housekeeping ()
+   self.outgoing_ipv4_fragments_alarm:check()
+end
+
 function selftest()
    print("selftest: apps.ipv4.fragment")
 

src/apps/ipv4/reassemble.lua

@@ -301,8 +301,6 @@ end
 function Reassembler:push ()
    local input, output = self.input.input, self.output.output
 
-   self.incoming_ipv4_fragments_alarm:check()
-
    for _ = 1, link.nreadable(input) do
       local pkt = link.receive(input)
       local h = ffi.cast(ether_ipv4_header_ptr_t, pkt.data)
@@ -327,6 +325,10 @@ function Reassembler:push ()
          packet.free(pkt)
       end
    end
+end
+
+function Reassembler:housekeeping ()
+   self.incoming_ipv4_fragments_alarm:check()
 
    if self.next_counter_update < engine.now() then
       -- Update counters every second, but add a bit of jitter to smooth

src/apps/ipv6/fragment.lua

@@ -172,8 +172,6 @@ function Fragmenter:push ()
    local input, output = self.input.input, self.output.output
    local max_length = self.mtu + ether_header_len
 
-   self.outgoing_ipv6_fragments_alarm:check()
-
    for _ = 1, link.nreadable(input) do
       local pkt = link.receive(input)
       local h = ffi.cast(ether_ipv6_header_ptr_t, pkt.data)
@@ -198,6 +196,10 @@ function Fragmenter:push ()
    end
 end
 
+function Fragmenter:housekeeping ()
+   self.outgoing_ipv6_fragments_alarm:check()
+end
+
 function selftest()
    print("selftest: apps.ipv6.fragment")
 

src/apps/ipv6/nd_light.lua

@@ -334,11 +334,6 @@ local function from_south (self, p)
 end
 
 function nd_light:push ()
-   if self._next_hop.nsent == 0 and self._eth_header == nil then
-      -- Kick off address resolution
-      self._next_hop.timer_cb()
-   end
-
    local cache = self._cache
    local l_in = self.input.south
    local l_out = self.output.north
@@ -382,6 +377,13 @@ function nd_light:push ()
    end
 end
 
+function nd_light:housekeeping ()
+   if self._next_hop.nsent == 0 and self._eth_header == nil then
+      -- Kick off address resolution
+      self._next_hop.timer_cb()
+   end
+end
+
 -- Free static packets on `stop'.
 function nd_light:stop ()
    packet.free(self._next_hop.packet)

src/apps/ipv6/reassemble.lua

@@ -302,8 +302,6 @@ end
 function Reassembler:push ()
    local input, output = self.input.input, self.output.output
 
-   self.incoming_ipv6_fragments_alarm:check()
-
    for _ = 1, link.nreadable(input) do
       local pkt = link.receive(input)
       local h = ffi.cast(ether_ipv6_header_ptr_t, pkt.data)
@@ -327,6 +325,10 @@ function Reassembler:push ()
          link.transmit(output, pkt)
       end
    end
+end
+
+function Reassembler:housekeeping ()
+   self.incoming_ipv6_fragments_alarm:check()
 
    if self.next_counter_update < engine.now() then
       -- Update counters every second, but add a bit of jitter to smooth

src/apps/lwaftr/ndp.lua

@@ -442,11 +442,6 @@ function NDP:push()
    local isouth, osouth = self.input.south, self.output.south
    local inorth, onorth = self.input.north, self.output.north
 
-   -- TODO: do unsolicited neighbor advertisement on start and on
-   -- configuration reloads?
-   -- This would be an optimization, not a correctness issue
-   self:maybe_send_ns_request(osouth)
-
    for _ = 1, link.nreadable(isouth) do
       local p = receive(isouth)
       if is_ndp(p) then
@@ -475,6 +470,13 @@ function NDP:push()
    end
 end
 
+function NDP:housekeeping()
+   -- TODO: do unsolicited neighbor advertisement on start and on
+   -- configuration reloads?
+   -- This would be an optimization, not a correctness issue
+   self:maybe_send_ns_request(self.output.south)
+end
+
 function selftest()
    print("selftest: ndp")