On 03/23/2015 03:24 PM, Lorenzo Pistone wrote:
I don't get the same message (obviously) with not -n but -t, however still no
packet gets out.
Well, with -t you'll be using sendto(), so that's expected.
So let me ask a stupid question, assuming you don't use -n and therefore
not hit this rounding bug, and you still cannot send a packet out ... is
your link from the device actually up (ip link)?
Are you perhaps checking with tcpdump if a packet has been sent out?
Il 23/03/2015 15:23, Lorenzo Pistone ha scritto:
So I tried now without -n, still absolutely no packet out on real devices (contrary to
lo), but when interrupting I get "Cannot destroy the TX_RING: Device or resource
busy!" for each CPU (so 4 times in my case). Looks like a start.
Il 23/03/2015 10:27, Daniel Borkmann ha scritto:
Hi Lorenzo,
On 03/22/2015 03:13 PM, Lorenzo Pistone wrote:
Hi,
I'm trying to send UDP packets with zero length withthis simple configuration
on trafgen:
{
# --- ethernet header ---
0xbe, 0x15, 0x1d, 0x12, 0x1c, 0x57, # mac destination
0xfa, 0x16, 0x3e, 0xa0, 0x5d, 0x18, # mac source
const16(0x0800), # protocol
# --- ip header ---
# ipv4 version (4-bit) + ihl (4-bit), tos
0b01000101, 0,
# ipv4 total len
const16(28),
# id (note: runtime dynamic random)
drnd(2),
# ipv4 3-bit flags + 13-bit fragment offset
# 001 = more fragments
0b01000000, 0,
64, # ttl
17, # proto udp
# dynamic ip checksum (note: offsets are zero indexed)
csumip(14, 33),
92, 222, 69, 15, # source ip
85, 214, 106, 103, # dest ip
# --- udp header ---
# as this is a fragment the below stuff does not matter too much
const16(48054), # src port
const16(28785), # dst port
const16(8), # udp length
# udp checksum can be dyn calc via csumudp(offset ip, offset tcp)
# which is csumudp(14, 34), but for udp its allowed to be zero
csumudp(14, 34),
}
I can send these packets on lo, but trafgen fails to send anything on real
devices. I used both the TX_RING and sendto method.
> I've tried with iwlwifi and virtio. mausezahn on the contrary works. I
checked with strace and there does not seem to be any
> call that returns an error.
Thanks for the bug report.
Can you provide some more debug information?
How do you invoke trafgen? strace -f? Something suspicious in dmesg? ip link?
Cheers,
Daniel
--
You received this message because you are subscribed to the Google Groups
"netsniff-ng" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
