network interfaces. This works by pre-computing the pseudo-header
checksum and caching it, delaying the actual checksum to ip_output()
if the hardware cannot perform the sum for us. In-bound checksums
can either be fully-checked by hardware, or summed up for final
verification by software. This method was modeled after how this
is done in FreeBSD, although the code is significantly different in
most places.
We don't delay checksums for IPv6/TCP, but we do take advantage of the
cached pseudo-header checksum.
Note: hardware-assisted checksumming defaults to "off". It is
enabled with ifconfig(8). See the manual page for details.
Implement hardware-assisted checksumming on the DP83820 Gigabit Ethernet,
3c90xB/3c90xC 10/100 Ethernet, and Alteon Tigon/Tigon2 Gigabit Ethernet.
based on the existing net/if_spppsubr.c stuff.
While there are completely userland (bpf based) implementations available,
those have a vastly larger per packet overhead thus causing major CPU
overhead and higher latency. On an i386 base router, running a 486DX at 50MHz
my line (768kBit/s downstream) was limited to something (varying) between 10
and 20 kByte/s effective download rate. With this implementation I get full
bandwidth (~85kByte/s).
This is client side only. Arguably the right way to add full PPPoE support
(including server side) would be a variation of the ppp line discipline and
appropriate modifications to pppd. I promise every help I can give to anyone
doing that - but I needed this realy fast. Besids, on low memory NAT boxes
with typically a single PPPoE connection, this implementation is more
lightweight than a pppd based one, which nicely fits my needs.
In this mode, the PPP packets start with the protocol identifier and don't
have any explicit framing (which may be added by the lower level driver).
Make input/output statistics a little bit more correct by adding a hardware
driver adjustable framing length for each packet (instead of the constant
value "3" used before).
While there, bump authentication name length from 32 to 48 (I have a
connection where I need more than 32). XXX - this should not be artificialy
limited at all.
tree, which allows a packet with Ethernet headers already present to
run through the ALTQ packet classifier. This is needed in order to
suport ALTQ on VLAN and bridge devices.
itojun