APFv6.1: addTransmitL4() optimizations

After this:
  atest 'NetworkStackTests:com.android.networkstack.android.net.apf.ApfFilterTest#testAllOffloadFeatureEnabled'
Generates a program with the following transmit instructions:
  (   1) 2297: transmit
  (   2) 2460: transmit    offload=ipv4/alert/icmp, partial_csum=0x0
  (   2) 2487: transmit    offload=ipv4/alert/icmp, partial_csum=0x0
  (   2) 2505: transmit    offload=ipv4/alert/icmp, partial_csum=0x0
  (   2) 2726: transmit    offload=ipv4/icmp, partial_csum=0x0
  (   3) 2890: transmit    offload=ipv6/alert/icmp, partial_csum=0xa6
  (   3) 2913: transmit    offload=ipv6/alert/icmp, partial_csum=0x52
  (   3) 2935: transmit    offload=ipv6/alert/icmp, partial_csum=0x52
  (   3) 2957: transmit    offload=ipv6/alert/icmp, partial_csum=0x52
  (   3) 2979: transmit    offload=ipv6/alert/icmp, partial_csum=0x52
  (   3) 3001: transmit    offload=ipv6/alert/icmp, partial_csum=0x52
  (   3) 3192: transmit    offload=ipv6/icmp, partial_csum=0x3a
  (   3) 3435: transmit    offload=ipv6/icmp, partial_csum=0x3a
  (   3) 4047: transmitudp offload=ipv4/udp, partial_csum=0x1ff
  (   3) 4078: transmitudp offload=ipv6/udp, partial_csum=0x1ff
  (   3) 4196: transmitudp offload=ipv4/udp, partial_csum=0x149
  (   3) 4227: transmitudp offload=ipv6/udp, partial_csum=0x149
  (   3) 4327: transmitudp offload=ipv4/udp, partial_csum=0x176
  (   3) 4358: transmitudp offload=ipv6/udp, partial_csum=0x176
  (   3) 4465: transmitudp offload=ipv4/udp, partial_csum=0x1b9
  (   3) 4496: transmitudp offload=ipv6/udp, partial_csum=0x1b9
  (   0) 4503: PASS

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I5391fedfbb7c32345392f2b9a013c839de3f2703
3 files changed