Date   

Re: BPF dev env

O Mahony, Billy <billy.o.mahony@...>
 

Thanks Brendan,

 

Good to know. I’ll take you up on that offer if (when!) I run in to problems.

 

/Billy.

 

From: Brenden Blanco [mailto:bblanco@...]
Sent: Tuesday, October 27, 2015 10:50 PM
To: O Mahony, Billy <billy.o.mahony@...>
Cc: iovisor-dev@...
Subject: Re: [iovisor-dev] BPF dev env

 

Hi Billy,

 

Yes, a VBox will work just fine to develop in. I personally test in both physical and kvm environments. AWS also works. So far, most of the examples are self-contained on a single machine, running in namespaces, etc.

 

Thanks, let us know if you have any troubles getting the environment working!

 

-Brenden

 

On Tue, Oct 27, 2015 at 3:00 AM, O Mahony, Billy via iovisor-dev <iovisor-dev@...> wrote:

Hi All,

is a Virtual Box VM a good environment to start compiling and investigating the various BPF *networking* examples at iovisor.github.com ?

Regards,
Billy.


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IO Visor booth volunteers for OPNFV

Valentina Alaria <vale@...>
 

If you plan to attend OPNFV next week in Burlingame please LMK if you'd be available to help with booth duty on Wednesday 11/11 and Thursday 11/12.

We have extra passes available for booth duty volunteers.

Thanks!

--

Valentina Alaria 
Head Product & Solutions Marketing
PLUMgrid 
v@... | cell 415.533.2651


bpf_trace_printk

O Mahony, Billy <billy.o.mahony@...>
 

Hi,

Where should I see o/p from bpf_trace_printk() ?

I've added bpf_trace_printk to examples/simple_tc. And also a long sleep after the veth pair is setup.

It compiles without complaint. After I start the simple_tc I add ip addrs to the veth pair with ifconfig. And ping the assigned addresses which works. But I don't see any o/p in dmesg for example.

Below are the changes to simple_tc.py along with the filter itself which had to go into it's own .c file in order to compile once the trace was added.

Regards,
Billy.



billy@ubuntu:~/iovisor/bcc/examples$ git diff
diff --git a/examples/simple_tc.py b/examples/simple_tc.py
index 4dd8aa5..01843b3 100755
--- a/examples/simple_tc.py
+++ b/examples/simple_tc.py
@@ -4,6 +4,7 @@

from bcc import BPF
from pyroute2 import IPRoute
+import time

ipr = IPRoute()

@@ -14,7 +15,7 @@ int hello(struct __sk_buff *skb) {
"""

try:
- b = BPF(text=text, debug=0)
+ b = BPF(src_file="simple_tc.c", debug=0)
fn = b.load_func("hello", BPF.SCHED_CLS)
ipr.link_create(ifname="t1a", kind="veth", peer="t1b")
idx = ipr.link_lookup(ifname="t1a")[0]
@@ -25,6 +26,7 @@ try:
ipr.tc("add", "sfq", idx, "1:")
ipr.tc("add-filter", "bpf", idx, ":1", fd=fn.fd,
name=fn.name, parent="1:", action="ok", classid=1)
+ time.sleep(60)
finally:
if "idx" in locals(): ipr.link_remove(idx)
print("BPF tc functionality - SCHED_CLS: OK")
billy@ubuntu:~/iovisor/bcc/examples$



billy@ubuntu:~/iovisor/bcc$ cat examples/simple_tc.c
#include <uapi/linux/ptrace.h>
#include <linux/blkdev.h>

int hello(struct __sk_buff *skb) {
bpf_trace_printk("meep\n");
return 1;
}


Re: bpf_trace_printk

Daniel Borkmann
 

On 11/11/2015 06:41 PM, O Mahony, Billy via iovisor-dev wrote:
Hi,

Where should I see o/p from bpf_trace_printk() ?
Depends where you have tracefs mounted, f.e.

cat /sys/kernel/debug/tracing/trace_pipe

Cheers,
Daniel


Re: bpf_trace_printk

Brenden Blanco <bblanco@...>
 

Hi,

The output goes into /sys/kernel/debug/tracing/trace_pipe (or elswhere
depending where you mount debugfs). If you look at the hello_world.py
example, it uses a helper in the BPF class, trace_print(), which does
a continuous read from the trace_pipe for you.

You could add a similar b.trace_print() in place of time.sleep(60), or
open a separate shell and do `cat
/sys/kernel/debug/tracing/trace_pipe`.

Thanks,
Brenden

On Wed, Nov 11, 2015 at 9:41 AM, O Mahony, Billy via iovisor-dev
<iovisor-dev@...> wrote:
Hi,

Where should I see o/p from bpf_trace_printk() ?

I've added bpf_trace_printk to examples/simple_tc. And also a long sleep after the veth pair is setup.

It compiles without complaint. After I start the simple_tc I add ip addrs to the veth pair with ifconfig. And ping the assigned addresses which works. But I don't see any o/p in dmesg for example.

Below are the changes to simple_tc.py along with the filter itself which had to go into it's own .c file in order to compile once the trace was added.

Regards,
Billy.



billy@ubuntu:~/iovisor/bcc/examples$ git diff
diff --git a/examples/simple_tc.py b/examples/simple_tc.py
index 4dd8aa5..01843b3 100755
--- a/examples/simple_tc.py
+++ b/examples/simple_tc.py
@@ -4,6 +4,7 @@

from bcc import BPF
from pyroute2 import IPRoute
+import time

ipr = IPRoute()

@@ -14,7 +15,7 @@ int hello(struct __sk_buff *skb) {
"""

try:
- b = BPF(text=text, debug=0)
+ b = BPF(src_file="simple_tc.c", debug=0)
fn = b.load_func("hello", BPF.SCHED_CLS)
ipr.link_create(ifname="t1a", kind="veth", peer="t1b")
idx = ipr.link_lookup(ifname="t1a")[0]
@@ -25,6 +26,7 @@ try:
ipr.tc("add", "sfq", idx, "1:")
ipr.tc("add-filter", "bpf", idx, ":1", fd=fn.fd,
name=fn.name, parent="1:", action="ok", classid=1)
+ time.sleep(60)
finally:
if "idx" in locals(): ipr.link_remove(idx)
print("BPF tc functionality - SCHED_CLS: OK")
billy@ubuntu:~/iovisor/bcc/examples$



billy@ubuntu:~/iovisor/bcc$ cat examples/simple_tc.c
#include <uapi/linux/ptrace.h>
#include <linux/blkdev.h>

int hello(struct __sk_buff *skb) {
bpf_trace_printk("meep\n");
return 1;
}
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conf call today for IOVisor

Pere Monclus
 

we are having some problems with Webex and most of the people is busy with OPNFV conference. We will reschedule it.
regards,
pere


Re: bpf_trace_printk

O Mahony, Billy <billy.o.mahony@...>
 

Hi Daniel & Brendan,

Cool. Thanks for the help!

One thing I notice is that immediately after I assign ip addrs to the endpoints of the veth pair I see several log messages:

<idle>-0 [000] .Ns. 73082.699758: : meep
ksoftirqd/0-3 [000] ..s. 73082.699828: : meep
<idle>-0 [000] ..s. 73082.960638: : meep
kworker/0:2-4011 [000] ..s. 73083.146783: : meep
kworker/0:2-4011 [000] ..s1 73083.346750: : meep
<idle>-0 [000] ..s. 73083.368876: : meep
kworker/0:2-4011 [000] ..s. 73084.146130: : meep
kworker/0:2-4011 [000] ..s. 73084.146238: : meep

But thereafter when I ping either of the assigned addresses I don't see any further invocations of the log message. I was expecting it to be called for each eth frame received by the either of the interfaces.

Billy.

-----Original Message-----
From: Brenden Blanco [mailto:bblanco@...]
Sent: Wednesday, November 11, 2015 5:49 PM
To: O Mahony, Billy <billy.o.mahony@...>
Cc: iovisor-dev@...
Subject: Re: [iovisor-dev] bpf_trace_printk

Hi,

The output goes into /sys/kernel/debug/tracing/trace_pipe (or elswhere
depending where you mount debugfs). If you look at the hello_world.py
example, it uses a helper in the BPF class, trace_print(), which does a
continuous read from the trace_pipe for you.

You could add a similar b.trace_print() in place of time.sleep(60), or open a
separate shell and do `cat /sys/kernel/debug/tracing/trace_pipe`.

Thanks,
Brenden

On Wed, Nov 11, 2015 at 9:41 AM, O Mahony, Billy via iovisor-dev <iovisor-
dev@...> wrote:
Hi,

Where should I see o/p from bpf_trace_printk() ?

I've added bpf_trace_printk to examples/simple_tc. And also a long sleep
after the veth pair is setup.

It compiles without complaint. After I start the simple_tc I add ip addrs to
the veth pair with ifconfig. And ping the assigned addresses which works. But
I don't see any o/p in dmesg for example.

Below are the changes to simple_tc.py along with the filter itself which had
to go into it's own .c file in order to compile once the trace was added.

Regards,
Billy.



billy@ubuntu:~/iovisor/bcc/examples$ git diff diff --git
a/examples/simple_tc.py b/examples/simple_tc.py index
4dd8aa5..01843b3
100755
--- a/examples/simple_tc.py
+++ b/examples/simple_tc.py
@@ -4,6 +4,7 @@

from bcc import BPF
from pyroute2 import IPRoute
+import time

ipr = IPRoute()

@@ -14,7 +15,7 @@ int hello(struct __sk_buff *skb) { """

try:
- b = BPF(text=text, debug=0)
+ b = BPF(src_file="simple_tc.c", debug=0)
fn = b.load_func("hello", BPF.SCHED_CLS)
ipr.link_create(ifname="t1a", kind="veth", peer="t1b")
idx = ipr.link_lookup(ifname="t1a")[0] @@ -25,6 +26,7 @@ try:
ipr.tc("add", "sfq", idx, "1:")
ipr.tc("add-filter", "bpf", idx, ":1", fd=fn.fd,
name=fn.name, parent="1:", action="ok", classid=1)
+ time.sleep(60)
finally:
if "idx" in locals(): ipr.link_remove(idx) print("BPF tc
functionality - SCHED_CLS: OK") billy@ubuntu:~/iovisor/bcc/examples$



billy@ubuntu:~/iovisor/bcc$ cat examples/simple_tc.c #include
<uapi/linux/ptrace.h> #include <linux/blkdev.h>

int hello(struct __sk_buff *skb) {
bpf_trace_printk("meep\n");
return 1;
}
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Re: bpf_trace_printk

Daniel Borkmann
 

On 11/12/2015 12:14 AM, O Mahony, Billy wrote:
...
One thing I notice is that immediately after I assign ip addrs to the endpoints of the veth pair I see several log messages:

<idle>-0 [000] .Ns. 73082.699758: : meep
ksoftirqd/0-3 [000] ..s. 73082.699828: : meep
<idle>-0 [000] ..s. 73082.960638: : meep
kworker/0:2-4011 [000] ..s. 73083.146783: : meep
kworker/0:2-4011 [000] ..s1 73083.346750: : meep
<idle>-0 [000] ..s. 73083.368876: : meep
kworker/0:2-4011 [000] ..s. 73084.146130: : meep
kworker/0:2-4011 [000] ..s. 73084.146238: : meep

But thereafter when I ping either of the assigned addresses I don't see any further invocations of the log message. I was expecting it to be called for each eth frame received by the either of the interfaces.
Ahh, they're not being moved into different netns'es in your
given setup, right? So, maybe try ping with -I on the peer?


Re: bpf_trace_printk

Alexei Starovoitov
 

On Wed, Nov 11, 2015 at 3:14 PM, O Mahony, Billy via iovisor-dev
<iovisor-dev@...> wrote:

But thereafter when I ping either of the assigned addresses I don't see any further invocations of the log message. I was expecting it to be called for each eth frame received by the either of the interfaces.
if you're actually doing 'ping IPaddr' of veth interface,
it doesn't actually go into that veth.
If 'ip -s link show veth0' doesn't show stats incrementing
it means that packets are not seen by the device,
so won't be seen by qdisc and won't be seen by bpf either.


Re: bpf_trace_printk

O Mahony, Billy <billy.o.mahony@...>
 

Hi Alexei,

Thanks. I suspected something surprising like that going on!

I'd like to build a toy router with eBPF just to route some frames between interfaces.

So ideally I'd like to attach my eBPF program to frame ingress on a device, parse it and egress it on another device.

What's the best example to deep-dive into - I was thinking tc_neighbor_sharing?

/Billy.

-----Original Message-----
From: Alexei Starovoitov [mailto:alexei.starovoitov@...]
Sent: Wednesday, November 11, 2015 11:51 PM
To: O Mahony, Billy <billy.o.mahony@...>
Cc: Brenden Blanco <bblanco@...>; Daniel Borkmann
<daniel@...>; iovisor-dev@...
Subject: Re: [iovisor-dev] bpf_trace_printk

On Wed, Nov 11, 2015 at 3:14 PM, O Mahony, Billy via iovisor-dev <iovisor-
dev@...> wrote:

But thereafter when I ping either of the assigned addresses I don't see any
further invocations of the log message. I was expecting it to be called for
each eth frame received by the either of the interfaces.

if you're actually doing 'ping IPaddr' of veth interface, it doesn't actually go
into that veth.
If 'ip -s link show veth0' doesn't show stats incrementing it means that
packets are not seen by the device, so won't be seen by qdisc and won't be
seen by bpf either.


Re: bpf_trace_printk

Brenden Blanco <bblanco@...>
 

Hi, I would suggest something like tests/cc/test_brb.py or
tests/cc/test_brb2.py. The brb stands for bridge-router-bridge, with a
router implemented in a linux namespace in both versions. brb has the
bridge implemented in bpf, while brb2 has the bridge implemented as a
namespace, so you can compare and contrast.

On Thu, Nov 12, 2015 at 1:57 AM, O Mahony, Billy via iovisor-dev
<iovisor-dev@...> wrote:
Hi Alexei,

Thanks. I suspected something surprising like that going on!

I'd like to build a toy router with eBPF just to route some frames between interfaces.

So ideally I'd like to attach my eBPF program to frame ingress on a device, parse it and egress it on another device.

What's the best example to deep-dive into - I was thinking tc_neighbor_sharing?

/Billy.



-----Original Message-----
From: Alexei Starovoitov [mailto:alexei.starovoitov@...]
Sent: Wednesday, November 11, 2015 11:51 PM
To: O Mahony, Billy <billy.o.mahony@...>
Cc: Brenden Blanco <bblanco@...>; Daniel Borkmann
<daniel@...>; iovisor-dev@...
Subject: Re: [iovisor-dev] bpf_trace_printk

On Wed, Nov 11, 2015 at 3:14 PM, O Mahony, Billy via iovisor-dev <iovisor-
dev@...> wrote:

But thereafter when I ping either of the assigned addresses I don't see any
further invocations of the log message. I was expecting it to be called for
each eth frame received by the either of the interfaces.

if you're actually doing 'ping IPaddr' of veth interface, it doesn't actually go
into that veth.
If 'ip -s link show veth0' doesn't show stats incrementing it means that
packets are not seen by the device, so won't be seen by qdisc and won't be
seen by bpf either.
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https://lists.iovisor.org/mailman/listinfo/iovisor-dev


[Update] IOvisor TSC & Dev Members call

bblanco@...
 

Hi All,

It has been several weeks since our last meeting, so let's meet tomorrow and recap as well as plan the next steps!

There has been quite a bit of activity over the past month which would be good to summarize, including many conferences and some coding updates.

* Conference summary
- Tokyo, OPNFV, P4 Workshop

* Coding
- IO Module definition progress
- ODL/GBP integration work
- P4 support


As a topic for the meeting, I would like to discuss further details of the IO Module concept, specific architectural choices to be made, and the upcoming work with regards to ODL/GBP.

Please let us know if there is an additional topic to be added to the agenda.

IOvisor TSC & Dev Members call

Agenda :

1) Update on IOVisor Module design and progress on top of eBPF engine
2) discussion about YAML model for Control Plane of IOVisor Modules and their REST APIs
3) Brainstorm on how to integrate IOVisor Module abstraction in DPDK


details for the call:

IOvisor TSC & Dev Members call
Wednesday, October 14, 2015
11:00 am | Eastern Daylight Time (New York, GMT-04:00) | 1 hr 30 mins

Join WebEx meeting
https://plumgrid.webex.com/plumgrid/j.php?MTID=mad00b9597a507885b5e2b3ee0c4166af
Meeting number: 809 028 432
Meeting password: iovisor

Join by phone
+1-415-655-0003 US TOLL
Access code: 809 028 432
Global call-in numbers

When
Wed Nov 25, 2015 11am – 12pm Pacific Time
Where
webex, link attached (map)
Video call
https://plus.google.com/hangouts/_/plumgrid.com/iovisor
Who
Pere Monclus - organizer
christopher.price@...
prem@...
David Duffey
Sushil Singh
Affan Ahmed Syed
wardd@...
krb@...
developer@...
Brenden Blanco
mbudiu@...
yunsong.lu@...
Rich Lane
Neela Jacques
Ed Doe
John Zannos
iovisor-dev@...
bkanekar@...
uri.elzur@...
john fastabend
Alexei Starovoitov
mc3124@...
jianwen.pi@...
Bhushan Kanekar
Prasun Kapoor
aclark@...


Re: [Update] IOvisor TSC & Dev Members call

Keith Burns (krb) <krb@...>
 

See you there.

On Nov 24, 2015 10:27 PM, bblanco@... wrote:

Hi All,

It has been several weeks since our last meeting, so let's meet tomorrow and recap as well as plan the next steps!

There has been quite a bit of activity over the past month which would be good to summarize, including many conferences and some coding updates.

* Conference summary
- Tokyo, OPNFV, P4 Workshop

* Coding
- IO Module definition progress
- ODL/GBP integration work
- P4 support


As a topic for the meeting, I would like to discuss further details of the IO Module concept, specific architectural choices to be made, and the upcoming work with regards to ODL/GBP.

Please let us know if there is an additional topic to be added to the agenda.

IOvisor TSC & Dev Members call

Agenda :

1) Update on IOVisor Module design and progress on top of eBPF engine
2) discussion about YAML model for Control Plane of IOVisor Modules and their REST APIs
3) Brainstorm on how to integrate IOVisor Module abstraction in DPDK


details for the call:

IOvisor TSC & Dev Members call
Wednesday, October 14, 2015
11:00 am | Eastern Daylight Time (New York, GMT-04:00) | 1 hr 30 mins

Join WebEx meeting
https://plumgrid.webex.com/plumgrid/j.php?MTID=mad00b9597a507885b5e2b3ee0c4166af
Meeting number: 809 028 432
Meeting password: iovisor

Join by phone
+1-415-655-0003 US TOLL
Access code: 809 028 432
Global call-in numbers

When
Wed Nov 25, 2015 11am – 12pm Pacific Time
Where
webex, link attached (map)
Video call
https://plus.google.com/hangouts/_/plumgrid.com/iovisor
Who
Pere Monclus
- organizer
christopher.price@...
prem@...
David Duffey
Sushil Singh
Affan Ahmed Syed
wardd@...
krb@...
developer@...
Brenden Blanco
mbudiu@...
yunsong.lu@...
Rich Lane
Neela Jacques
Ed Doe
John Zannos
iovisor-dev@...
bkanekar@...
uri.elzur@...
john fastabend
Alexei Starovoitov
mc3124@...
jianwen.pi@...
Bhushan Kanekar
Prasun Kapoor
aclark@...


[Update] IOvisor TSC & Dev Members call

Pere Monclus
 

here you have the correct invite for today

https://plumgrid.webex.com/plumgrid/e.php?MTID=m7d73fc36b3276e943c1270060b2c628a

IOvisor TSC & Dev Members call

Agenda :

1) Update on IOVisor Module design and progress on top of eBPF engine
2) discussion about YAML model for Control Plane of IOVisor Modules and their REST APIs
3) Brainstorm on how to integrate IOVisor Module abstraction in DPDK


details for the call:

IOvisor TSC & Dev Members call
Wednesday, October 14, 2015
11:00 am | Eastern Daylight Time (New York, GMT-04:00) | 1 hr 30 mins

Join WebEx meeting
https://plumgrid.webex.com/plumgrid/j.php?MTID=mad00b9597a507885b5e2b3ee0c4166af
Meeting number: 809 028 432
Meeting password: iovisor

Join by phone
+1-415-655-0003 US TOLL
Access code: 809 028 432
Global call-in numbers

When
Wed Nov 25, 2015 11am – 12pm Pacific Time
Where
webex, link attached (map)
Video call
https://plus.google.com/hangouts/_/plumgrid.com/iovisor
Who
Pere Monclus - organizer
Ed Doe
Prasun Kapoor
Neela Jacques
mbudiu@...
john fastabend
iovisor-dev@...
developer@...
aclark@...
Sushil Singh
wardd@...
krb@...
jianwen.pi@...
prem@...
bkanekar@...
christopher.price@...
David Duffey
Alexei Starovoitov
Brenden Blanco
Rich Lane
Bhushan Kanekar
yunsong.lu@...
John Zannos
Affan Ahmed Syed
mc3124@...
uri.elzur@...


IOVisor TSC/Dev Meeting Minutes 2015-11-25

Brenden Blanco <bblanco@...>
 

Hi All, here are the (belated due to holidays) meeting minutes for last week.

=== Attendees ===

Affan Syed
Brendan Gregg
Brenden Blanco
Daniel Borkmann
Jianwen Pi
Keith Burns
Luis Rodriguez
Mihai Budiu
Pere Monclus
Rich Lane
Yonghong Song

=== Discussion ===

We had a lively discussion about IO Modules. The thesis so far is that the definition of an IO Module has not yet been clearly specified, and eBPF itself is too flexible and too open (many hook points, many use cases with different inputs, etc.) to the point that it is difficult to conceptualize the notion of a module. Simple tools such as the storage monitoring examples are okay and self contained. But a chain of IO modules that interacts i) between themselves, ii) with linux kernel components, will be difficult until we close the definition and remove some of the flexibility.

AI: Brenden
 - create a proposal of 'net interface' and 'io module' to discuss within the mailing list
 note: for now defocus some on performance, e.g. no high rate CP<->DP interaction

The idea will be to build up the initial concepts around the GBP use case.

Also, so far there is a concept of a host local module manager, comparable to libvirtd to networking, which holds the running modules and their relationship/connectivity to each other. A developer from PG with some spare cycles has been prototyping a GUI that would one day go on top of this rest API, which was demoed during this meeting. The code for this should go up on github before the next meeting.

=== Summary of previous month activities ===

Since the last meeting, IOVisor participated in several conferences:

OpenStack Tokyo
 - 2 hour discussion/tutorial
 - NFV architecture overview from PoV of Huawei
 - demo of Mesos+docker/libnetwork+iovisor integration

OPNFV
 - several panels
 - 2 days of booth, lots of good questions

P4 Workshop
 - 15 minute intro to iovisor+P4
 - p4 + rest api + iperf demo
  AI: simple_router demo was buggy, Mihai to add bugfix

=== Code changes ===

iovisor/bcc:
 - p4 frontend updates from mbudiu
 - p4-demo branch is available for people to try
 - upcoming: packaging support for suse and archlinux

iovisor/iomodules:
 new project, rest-based plugin manager for iomodules

odl/gbp:
 iovisor renderer support in progress from kburns+adetalhouet


IOVisor TSC & Dev Members call Agenda

Brenden Blanco <bblanco@...>
 

Hi All,

Tomorrow in the TSC/Dev call, I would like to continue on the previous meeting's topic of IO Module definition.

To bring some concreteness to the discussion, I have just pushed a set of sample code for an IO Module Manager (I code-named it "hive" for now, though that name is already taken) to https://github.com/iovisor/iomodules.

What you'll find there is by no means complete (nor really even functional), but hopefully there is enough meat there to be able to serve as a talking point for a discussion. Of note, the files iomodule.h and the contents of server.go:NewServer() capture my thoughts for the minimal dataplane and control plane APIs, respectively.

If there are additional topics to add to the agenda, please reply here as well.

In the morning I will send Webex Dial-in info.

Thanks,
Brenden Blanco


Re: IOVisor TSC & Dev Members call Agenda

Brenden Blanco <bblanco@...>
 

Hi All, below you will find the dial-in info for the meeting.

If you are receiving this email because you are on the iovisor-dev@... mailing list, please also consider yourself invited!

===================================================

IOVisor TSC/Dev Meeting
Wednesday, December 9, 2015
11:00 am  |  Pacific Standard Time (San Francisco, GMT-08:00)  |  1 hr
 
Join WebEx meeting
Meeting number:803 752 390
Meeting password:iovisor
 
Join by phone
+1-415-655-0003 US TOLL
Access code: 803 752 390
Global call-in numbers


On Tue, Dec 8, 2015 at 11:58 PM, Brenden Blanco <bblanco@...> wrote:
Hi All,

Tomorrow in the TSC/Dev call, I would like to continue on the previous meeting's topic of IO Module definition.

To bring some concreteness to the discussion, I have just pushed a set of sample code for an IO Module Manager (I code-named it "hive" for now, though that name is already taken) to https://github.com/iovisor/iomodules.

What you'll find there is by no means complete (nor really even functional), but hopefully there is enough meat there to be able to serve as a talking point for a discussion. Of note, the files iomodule.h and the contents of server.go:NewServer() capture my thoughts for the minimal dataplane and control plane APIs, respectively.

If there are additional topics to add to the agenda, please reply here as well.

In the morning I will send Webex Dial-in info.

Thanks,
Brenden Blanco


Changing packet fields before redirect

Ashhad Sheikh <ashhadsheikh394@...>
 

Hello, 
I there any way ton change the packet fields in BPF program before redirecting it to another ifindex.
I want to make changes in packet fields before redirecting it to next ifindex
i.e I want to change ARP request packet to response packet by making changes in its field.
arp->oper=0x0002 

bpf_clone_redirect won't work in this scenerio, tried bpf_redirect too but no luck so far.

Regards
Ashhad 
 


Re: Changing packet fields before redirect

Alexei Starovoitov
 

On Sat, Dec 19, 2015 at 11:20 AM, Ashhad Sheikh via iovisor-dev
<iovisor-dev@...> wrote:
Hello,
I there any way ton change the packet fields in BPF program before
redirecting it to another ifindex.
I want to make changes in packet fields before redirecting it to next
ifindex
i.e I want to change ARP request packet to response packet by making changes
in its field.
arp->oper=0x0002

bpf_clone_redirect won't work in this scenerio, tried bpf_redirect too but
no luck so far.
have you tried bpf_skb_store_bytes() to write into packet data ?
meta-data fields of skb are mostly read-only with few exceptions.


Using IOVisor to resize IP packets

Mat and Helen <matandhelen@...>
 

I’m interested in the possibility of using ebpf / IOVisor to add encapsulation to IP packets, or to translate IPv4 packets to IPv6.    Either of these would require me to increase the size of the packet header.


Can you tell me whether this is possible please?   Or is it outside of the scope of what can be done with ebpf? 


Many thanks!

21 - 40 of 2021