When you turn off ARP on a netdevice then the first packet always goes
out with a dstMAC of all zeroes. This is because the first packet is
used to resolve ARP entries. Even though the ARP entry may be resolved
(I tried by setting a static ARP entry for a host i was pinging from),
it gets overwritten by virtue of having the netdevice disabling ARP.
Subsequent packets go out fine with correct dstMAC address (which may
be why people have ignored reporting this issue).
To cut the story short:
the culprit code is in net/ethernet/eth.c::eth_header()
----
/*
* Anyway, the loopback-device should never use this
function...
*/
if (dev->flags & (IFF_LOOPBACK|IFF_NOARP))
{
memset(eth->h_dest, 0, dev->addr_len);
return ETH_HLEN;
}
if(daddr)
{
memcpy(eth->h_dest,daddr,dev->addr_len);
return ETH_HLEN;
}
----
Note how the h_dest is being reset when device has IFF_NOARP.
As a note:
All devices including loopback pass a daddr. loopback in fact passes
a 0 all the time ;->
This means i can delete the check totaly or i can remove the IFF_NOARP
Alexey says:
--------------------
I think, it was me who did this crap. It was so long ago I do not remember
why it was made.
I remember some troubles with dummy device. It tried to resolve
addresses, apparently, without success and generated errors instead of
blackholing. I think the problem was eventually solved at neighbour
level.
After some thinking I suspect the deletion of this chunk could change
behaviour of some parts which do not use neighbour cache f.e. packet
socket.
I think safer approach would be to move this chunk after if (daddr).
And the possibility to remove this completely could be analyzed later.
--------------------
Patch updated with Alexey's safer suggestions.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
This uses is_multicast_ether_addr() because it has recently been
changed to do the same thing these seperate tests are doing.
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
These patches add the header linux/if_ether.h and change 1500 to
ETH_DATA_LEN in some files.
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Expose faster ether compare for use by protocols and other
driver. And change name to be more consistent with other ether
address manipulation routines in same file
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
We know the thing is at least 2-byte aligned, so take
advantage of that instead of invoking memcmp() which
results in truly horrifically inefficient code because
it can't assume anything about alignment.
Signed-off-by: David S. Miller <davem@davemloft.net>
Of this type, mostly:
CHECK net/ipv6/netfilter.c
net/ipv6/netfilter.c:96:12: warning: symbol 'ipv6_netfilter_init' was not declared. Should it be static?
net/ipv6/netfilter.c:101:6: warning: symbol 'ipv6_netfilter_fini' was not declared. Should it be static?
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead, set it in one place, namely the beginning of
netif_receive_skb().
Based upon suggestions from Jamal Hadi Salim.
Signed-off-by: David S. Miller <davem@davemloft.net>
tr_type_trans(), hippi_type_trans() left as-is.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ross moved. Remove the bad email address so people will find the correct
one in ./CREDITS.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Jörn Engel
Jamal Hadi Salim
Kris Katterjohn
Stephen Hemminger
David S. Miller
David S. Miller
Arnaldo Carvalho de Melo
Alexey Dobriyan
Denis Vlasenko
Jesper Juhl
Linus Torvalds