Key and mask for matching destination is in table. We need this
information in the action. However this information is not exposed, so
we need to specify another parameter with the same information as in
the key(s).
Log from slack: (2019-03-14)
nico [1:55 PM]
If I use LPM for matching, can I easily get the network address from P4 or do I have to use a bitmask myself? In the latter case it is not exactly clear how to get the mask from the table
Nate Foster [1:58 PM]
You want to retrieve the address in the packet? In a table?
And do you want to do the retrieving from the data plane or the control plane? (edited)
nico [2:00 PM]
If I have a match in a table that matches on LPM, it can be any IP address in a network
For calculating the NAT64/NAT46 translation, I will need the base address, i.e. network address to do subtractions/additions
So it is fully data plane, what I would like to do
I'll commit sample code to show the use case more clearly
So the action nat64_static() is used in the table v6_networks.
In v6_networks I use a match on `hdr.ipv6.dst_addr: lpm;`
What I would like to be able is to get the network address ; I can do that manually, if I have the mask
I can also re-inject this parameter by another action argument, but I'd assume that I can somewhere read this out from the table / match
Nate Foster [2:15 PM]
To make sure I understand, in the data plane, you want to retrieve the address in the lpm pattern? (edited)
nico [2:16 PM]
I want to retrieve the key
Nate Foster [2:16 PM]
Wait. The value `hdr.ipv6.dst_addr` is the thing used in the match.
So you have that.
What you don’t have is the IPv6 address and mask put into the table by the control plane.
I assume you want the latter, right?
nico [2:17 PM]
For example, if my matching key is 2001:db8::/32 and the real address is 2001:db8::f00, then I would like to retrieve 2001:db8:: and 32 from the table
exactly :slightly_smiling_face:
I can "fix" this by adding another argument, but it feels somewhat wrong to do that
Because the table already knows this information
Nate Foster [2:26 PM]
I can’t think of a way other than the action parameter hack.
nico [2:26 PM]
Oh, ok
Is it because the information is "lost in hardware"?
Nate Foster [2:31 PM]
No you’re right that most implementations have the value in memory. And one can imagine a different table API that allowed one to retrieve it in the data plane.
But unless I am missing something obvious, P4 hides it…
\end{verbatim}
no meta information
\begin{verbatim}
Is there any meta information for "from which table was the action
called" available? My use case is having a debug action that sends
packets to the controller and I use it as a default_action in various
tables; however know I don't know anymore from which table the action
was called. Is there any kind of meta information which table called
me available?
I could work around this by using if(! .. .hit) { my_action(table_id)
}, but it would not work with using default_action = ...
\end{verbatim}
type definitions separate
Code sharing (controller, switch)
\begin{verbatim}
*** DONE Synchronisation with the controller
- Double data type definition -> might differ
- TYPE_CPU for ethernet
- Port ingress offset (9 vs. 16 bit)
\end{verbatim}
No switch in actions, No conditional execution in actions
P4os - reusable code
\begin{verbatim}
Not addressed so far: how to create re-usable code fragments that can
be plugged in easily. There could be a hypothetical "P4OS" that
manages code fragments. This might include, but not limited to
downloading (signed?) source code, managing dependencies similar to
Linux package management, handling updates, etc.
\end{verbatim}
idomatic problem: Security issue: not checking checksums before
If I am not totally mistaken, the following is happening with the netpfga:
I was testing sending and receiving packets on the same computer; so I sent a packet on nfX and expected an answer on nf0, which is how I wanted to verify that the card works
So I ran tcpdump on nf0, send a packet with ping6 and scapy on nf{0,1,2,3} (edited)
I have never seen the switch emitting ANY packet back with tcpdump
Now with the card connected to another host, sending neighbor solicitation, I see duplicated packets on the other host - so it seems that it might have worked all the time, just that tcpdump on nfX on the host which contains the card does not show the packets
\end{verbatim}
debugging generated tcl code to debug impl1 error
Cable problems:
\begin{verbatim}
[ 488.265148] ixgbe 0000:02:00.0: failed to initialize because an unsupported SFP+ module type was detected.
[ 488.265157] ixgbe 0000:02:00.0: Reload the driver after installing a supported module.
[ 488.265605] ixgbe 0000:02:00.0: removed PHC on enp2s0f0
function syntax not supported, using defines instead
4-6 MB logfiles for a compile process.
confusing messages
\begin{verbatim}
WARNING: command 'get_user_parameter' will be removed in the 2015.3
release, use 'get_user_parameters' instead
\end{verbatim}
critical non critical errors
\begin{verbatim}
CRITICAL WARNING: [BD 41-737] Cannot set the parameter TRANSLATION_MODE on /axi_interconnect_0. It is read-only.
\end{verbatim}
\begin{verbatim}
- step9 (sume simulation, the longest step) in the process calls
"config_writes.py"
- config_writes.py fails with a syntax error, as it is incomplete
python code
- config_writes.py and config_writes.sh are generated by
gen_config_writes.py
- gen_config_writes.py reads config_writes.txt
- config_writes.txt is created in step 5 (sdnet simulation)
- step 5 consists of running xsc, xelab and xsim
- xsim (re-)generates config_writes.txt according to a watch ls -l
on the file: ${XILINX_VIVADO}/bin/xsim --runall
SimpleSumeSwitch_tb#work.glbl
- it seems (by grep -r) that ./Testbench/SimpleSumeSwitch_tb.sv is
responsible for writing config_writes.txt
- It seems that the "task" "SV_write_control" inside that file is
responsible for writing the content, which in turn uses
axi4_lite_master_write_request_control
\end{verbatim}
\begin{verbatim}
- Cannot easily run P4 on notebook - changes to the system very
invasive
- Varous compiler bugs/limitations
- Very very deep rabbithole problems
- Hanging/sleeping issue -- unclear whether it does something or
not
- Open impl_1 error with unclear reason
- logfiles referenced that don't exist
Run output will be captured here: /home/nico/projects/P4-NetFPGA/contrib-projects/sume-sdnet-switch/projects/minip4/simple_sume_switch/hw/project/simple_sume_switch.runs/synth/runme.log
nico@nsg-System:~/master-thesis/netpfga/log$ ls -alh /home/nico/projects/P4-NetFPGA/contrib-projects/sume-sdnet-switch/projects/minip4/simple_sume_switch/hw/project/simple_sume_switch.runs/synth/runme.log
ls: cannot access '/home/nico/projects/P4-NetFPGA/contrib-projects/sume-sdnet-switch/projects/minip4/simple_sume_switch/hw/project/simple_sume_switch.runs/synth/runme.log': No such file or directory
nico@nsg-System:~/master-thesis/netpfga/minip4/testdata$ less /home/nico/projects/P4-NetFPGA/contrib-projects/sume-sdnet-switch/projects/minip4/simple_sume_switch/hw/project/simple_sume_switch.runs/control_sub_m02_data_fifo_0_synth_1/runme.log
/home/nico/projects/P4-NetFPGA/contrib-projects/sume-sdnet-switch/projects/minip4/simple_sume_switch/hw/project/simple_sume_switch.runs/control_sub_m02_data_fifo_0_synth_1/runme.log: No such file or directory
- Wrong warnings: using 2018.2, getting warnings about things
removed in 2015.3
WARNING: command 'get_user_parameter' will be removed in the 2015.3
release, use 'get_user_parameters' instead
- A script/makefile generates a python script that generates a shell
script and later then a python script. If there is a mistake in
generating the first python script (syntax ok, but content is
not correct) then a much later stage of the compile process will
fail due to a syntax error in the third generated
script. However that syntax error is not fatal in the build
process and thus can only be seen with careful analysis of the
logfile, which is around 700 KiB or 10k lines per compile
process and contains 328 lines matching "error" and
"warning".
Most of the error and warning messages seem to be non-critical
(even if saying they are). Then there are a variety of INFO
messages that actually constitute ERROR messages, but are not
flagged as such nor do they cause the build process to abort.
\end{verbatim}
LPM tables don't work
match type exact - table must be at least 64 in size
multiple reboots sometimes required for flashing
Damaged, enlarged packets
\begin{verbatim}
** The NetPFGA saga
Problems encountered:
- The logfile for a compile run is 10k+ lines
- Many logged errors can actually be ignored (?) like:
ERROR: [VRFC 10-426] cannot find port tuple_out_sume_metadata_DATA on this module [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/wrapper/nf_sume_sdnet.v:219]
ERROR: [VRFC 10-426] cannot find port tuple_out_sume_metadata_VALID on this module [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/wrapper/nf_sume_sdnet.v:218]
ERROR: [VRFC 10-426] cannot find port tuple_in_sume_metadata_DATA on this module [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/wrapper/nf_sume_sdnet.v:185]
ERROR: [VRFC 10-426] cannot find port tuple_in_sume_metadata_VALID on this module [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/wrapper/nf_sume_sdnet.v:184]
ERROR: [VRFC 10-2063] Module <S_RESETTER_line> not found while processing module instance <S_RESET_clk_line> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/Simp
leSumeSwitch/SimpleSumeSwitch.v:332]
ERROR: [VRFC 10-2063] Module <S_RESETTER_lookup> not found while processing module instance <S_RESET_clk_lookup> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/
SimpleSumeSwitch/SimpleSumeSwitch.v:343]
ERROR: [VRFC 10-2063] Module <S_RESETTER_control> not found while processing module instance <S_RESET_clk_control> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_i
p/SimpleSumeSwitch/SimpleSumeSwitch.v:354]
ERROR: [VRFC 10-2063] Module <TopParser_t> not found while processing module instance <TopParser> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/SimpleSumeSwitc
h/SimpleSumeSwitch.v:436]
ERROR: [VRFC 10-2063] Module <TopPipe_lvl_t> not found while processing module instance <TopPipe_lvl> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/SimpleSumeS
witch/SimpleSumeSwitch.v:474]
ERROR: [VRFC 10-2063] Module <dummy_table_for_netpfga_t> not found while processing module instance <dummy_table_for_netpfga> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_s
ERROR: [VRFC 10-2063] Module <TopPipe_lvl_0_t> not found while processing module instance <TopPipe_lvl_0> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/SimpleS
umeSwitch/SimpleSumeSwitch.v:533]
ERROR: [VRFC 10-2063] Module <TopDeparser_t> not found while processing module instance <TopDeparser> [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/nf_sume_sdnet_ip/nf_sume_sdnet_ip/SimpleSumeS
INFO: [Vivado 12-5698] Checking validity of IPs in the design for the 'XSim' simulator...
CRITICAL WARNING: [BD 41-1356] Address block </M04_AXI/Reg> is not mapped into </S00_AXI>. Please use Address Editor to either map or exclude it.
CRITICAL WARNING: [BD 41-1356] Address block </M05_AXI/Reg> is not mapped into </S00_AXI>. Please use Address Editor to either map or exclude it.
WARNING: [VRFC 10-756] identifier state is used before its declaration [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/axis_sim_record_ip0/hdl/axis_sim_record.v:93]
WARNING: [VRFC 10-756] identifier ready_count is used before its declaration [/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.srcs/sources_1/ip/axis_sim_record_ip0/hdl/axis_sim_record.v:94]
INFO: [#UNDEF] Sorry, too many errors..
ERROR: [XSIM 43-3322] Static elaboration of top level Verilog design unit(s) in library work failed.
INFO: [USF-XSim-69] 'elaborate' step finished in '1' seconds
ERROR: [USF-XSim-62] 'elaborate' step failed with error(s). Please check the Tcl console output or '/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.sim/sim_1/behav/xsim/elaborate.log' file for more information.
${SUME_SDNET}/sw/sume/rwaxi -a 0x44020050-w 0x22222208
${SUME_SDNET}/sw/sume/rwaxi -a 0x44020054-w 0x00000822
${SUME_SDNET}/sw/sume/rwaxi -a 0x44020080-w 0x00000201
${SUME_SDNET}/sw/sume/rwaxi -a 0x44020040-w 0x00000001
nico@nsg-System:~$
- Misleading errors like
ERROR: [USF-XSim-62] 'elaborate' step failed with error(s). Please check the Tcl console output or '/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.sim/sim_1/behav/xsim/elaborate.log' file for more information.
nico@nsg-System:~/master-thesis/netpfga$ ls /home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.sim/sim_1/behav/xsim/elaborate.log
ls: cannot access '/home/nico/master-thesis/netpfga/minip4/simple_sume_switch/hw/project/simple_sume_switch.sim/sim_1/behav/xsim/elaborate.log': No such file or directory
- not using raise() and hiding source of errors (_hexify)
