This makes the user interface a little hostile. People thing of an MTU of 1500 bytes, but the corresponding packet is really 1514 bytes (including the 14 byte Ethernet header). A more friendly solution would configure the MTU (as before), but then derive the packet buffer size by adding the MAC header length. Instead, we define the packet buffer size then derive the MTU.
The MTU is not common currency in networking. On the wire, the only real issue is the MSS which is derived from MTU by subtracting the IP header and TCP header sizes (for the case of TCP). Now it is derived for the PKTSIZE by subtracting the IP header, the TCP header, and the MAC header sizes. So we should be all good and without the recurring 14 byte error in MTU's and MSS's.
Squashed commit of the following:
Trivial update to fix some spacing issues.
net/: Rename several macros containing _MTU to _PKTSIZE.
net/: Rename CONFIG_NET_SLIP_MTU to CONFIG_NET_SLIP_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_6LOWPAN_MTU to CONFIG_NET_6LOWPAN_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_ETH_MTU to CONFIG_NET_ETH_PKTSIZE. This is not the MTU which does not include the size of the link layer header. This is the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename the file d_mtu in the network driver structure to d_pktsize. That value saved there is not the MTU. The packetsize is the memory large enough to hold the maximum packet PLUS the size of the link layer header. The MTU does not include the link layer header.
lpc17: Removed duplicate configuration variable definitions from Kconfig: CONFIG_USBHOST_BULK_DISABLE, CONFIG_USBHOST_INT_DISABLE, and USBHOST_ISOC_DISABLE. These are global USBHOST configurations and are all defined in drivers/usbhost/Kconfig.
lpc17: Correct scope of naming of configuration variables: CONFIG_USBHOST_TDBUFFERS->CONFIG_LPC17_USBHOST_TDBUFFERS, CONFIG_USBHOST_TDBUFSIZE->CONFIG_LPC17_USBHOST_TDBUFSIZE, and CONFIG_USBHOST_IOBUFSIZE->CONFIG_LPC17_USBHOST_IOBUFSIZE
lpc17: Correct scope of naming of configuration variables: CONFIG_USBHOST_NEDS->CONFIG_LPC17_USBHOST_NEDS and CONFIG_USBHOST_NTDS->CONFIG_LPC17_USBHOST_NTDS
lpc17: Correct scope of naming of configuration variable: CONFIG_USBHOST_OHCIRAM_SIZE->CONFIG_LPC17_OHCIRAM_SIZE
Squashed commit of the following:
configs/*/README.txt: Replace each occurrence of './configure.sh' with 'tools/configure.sh'
configs/*/README.txt: Remove 'cd ..' after each './configure.sh'
configs/*/README.txt: Remove 'cd -' after each './configure.sh'
configs/*/README.txt: Remove 'cd tools' before each './configure.sh'
configs/README.txt: Remove instruction to CD tools/ before running configure.sh.
