P4 Debugger

[djshah19]

Hello,

Even though debugger is enabled. When executing ./p4dbg.py I get error - "The debugger is not enabled on the switch". Please help me on this.

Thanks, Dhwani

[antoninbas]

Did you use the --debugger command-line flag when starting the switch?

[djshah19]

I am running P4D2_2017_Spring/ipv4_forward program. To execute program I run ./run.sh file which starts the switches. Where shall I use --debugger command-line flag?

Please find below the logs:

fabtool@p4-dev:~/tutorials/P4D2_2017_Spring/exercises/ipv4_forward$ ./run.sh Entering build directory. Extracting package. Reading package manifest.

p4c-bm2-ss --p4v 16 "ipv4_forward.p4" -o "ipv4_forward.p4.json" Log directory /home/fabtool/tutorials/P4D2_2017_Spring/exercises/ipv4_forward/build/logs Pcap directory /home/fabtool/tutorials/P4D2_2017_Spring/exercises/ipv4_forward/build python2 "/home/fabtool/tutorials/P4D2_2017_Spring/utils/mininet/multi_switch_mininet.py" --log-dir "/home/fabtool/tutorials/P4D2_2017_Spring/exercises/ipv4_forward/build/logs" --manifest "./p4app.json" --target "multiswitch" --auto-control-plane --behavioral-exe "simple_switch" --json "ipv4_forward.p4.json" --cli-message "mininet_message.txt" Creating network Adding hosts: h1 h2 h3 Adding switches: s1 s2 s3 Adding links: (0ms delay) (0ms delay) (h1, s1) (0ms delay) (0ms delay) (h2, s2) (0ms delay) (0ms delay) (h3, s3) (0ms delay) (0ms delay) (s1, s2) (0ms delay) (0ms delay) (s1, s3) (0ms delay) (0ms delay) (s3, s2) Configuring hosts h1 h2 h3 Starting controller

*** Starting 3 switches s1 Starting P4 switch s1. simple_switch -i 1@s1-eth1 -i 2@s1-eth2 -i 3@s1-eth3 --pcap --thrift-port 9090 --nanolog ipc:///tmp/bm-0-log.ipc --device-id 0 ipv4_forward.p4.json --log-console P4 switch s1 has been started. s2 Starting P4 switch s2. simple_switch -i 1@s2-eth1 -i 2@s2-eth2 -i 3@s2-eth3 --pcap --thrift-port 9091 --nanolog ipc:///tmp/bm-1-log.ipc --device-id 1 ipv4_forward.p4.json --log-console P4 switch s2 has been started. s3 Starting P4 switch s3. simple_switch -i 1@s3-eth1 -i 2@s3-eth2 -i 3@s3-eth3 --pcap --thrift-port 9092 --nanolog ipc:///tmp/bm-2-log.ipc --device-id 2 ipv4_forward.p4.json --log-console P4 switch s3 has been started.

---

Configuring entries in p4 tables

Configuring switch... s3 table_set_default ipv4_lpm drop table_add ipv4_lpm ipv4_forward 10.0.3.10/32 => 00:aa:00:03:00:01 1 table_add ipv4_lpm ipv4_forward 10.0.1.10/32 => f2:ed:e6:df:4e:fb 2 table_add ipv4_lpm ipv4_forward 10.0.2.10/32 => f2:ed:e6:df:4e:fa 3 Obtaining JSON from switch... Done Control utility for runtime P4 table manipulation RuntimeCmd: Setting default action of ipv4_lpm action: drop runtime data: RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:03:0a/32 action: ipv4_forward runtime data: 00:aa:00:03:00:01 00:01 Entry has been added with handle 0 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:01:0a/32 action: ipv4_forward runtime data: f2:ed:e6:df:4e:fb 00:02 Entry has been added with handle 1 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:02:0a/32 action: ipv4_forward runtime data: f2:ed:e6:df:4e:fa 00:03 Entry has been added with handle 2 RuntimeCmd:

Configuring switch... s2 table_set_default ipv4_lpm drop table_add ipv4_lpm ipv4_forward 10.0.2.10/32 => 00:aa:00:02:00:02 1 table_add ipv4_lpm ipv4_forward 10.0.1.10/32 => 22:a8:04:41:ab:d3 2 table_add ipv4_lpm ipv4_forward 10.0.3.10/32 => 22:a8:04:41:ab:d4 3 Obtaining JSON from switch... Done Control utility for runtime P4 table manipulation RuntimeCmd: Setting default action of ipv4_lpm action: drop runtime data: RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:02:0a/32 action: ipv4_forward runtime data: 00:aa:00:02:00:02 00:01 Entry has been added with handle 0 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:01:0a/32 action: ipv4_forward runtime data: 22:a8:04:41:ab:d3 00:02 Entry has been added with handle 1 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:03:0a/32 action: ipv4_forward runtime data: 22:a8:04:41:ab:d4 00:03 Entry has been added with handle 2 RuntimeCmd:

Configuring switch... s1 table_set_default ipv4_lpm drop table_add ipv4_lpm ipv4_forward 10.0.1.10/32 => 00:aa:00:01:00:01 1 table_add ipv4_lpm ipv4_forward 10.0.2.10/32 => f2:ed:e6:df:4e:fa 2 table_add ipv4_lpm ipv4_forward 10.0.3.10/32 => f2:ed:e6:df:4e:fb 3 Obtaining JSON from switch... Done Control utility for runtime P4 table manipulation RuntimeCmd: Setting default action of ipv4_lpm action: drop runtime data: RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:01:0a/32 action: ipv4_forward runtime data: 00:aa:00:01:00:01 00:01 Entry has been added with handle 0 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:02:0a/32 action: ipv4_forward runtime data: f2:ed:e6:df:4e:fa 00:02 Entry has been added with handle 1 RuntimeCmd: Adding entry to lpm match table ipv4_lpm match key: LPM-0a:00:03:0a/32 action: ipv4_forward runtime data: f2:ed:e6:df:4e:fb 00:03 Entry has been added with handle 2 RuntimeCmd: Configuration complete.

---

---

Network configuration for: h1 Default interface: h1-eth0 10.0.1.10 00:04:00:00:00:01

---

---

Network configuration for: h2 Default interface: h2-eth0 10.0.2.10 00:04:00:00:00:02

---

---

Network configuration for: h3 Default interface: h3-eth0 10.0.3.10 00:04:00:00:00:03

---

====================================================================== Welcome to the BMV2 Mininet CLI!

Your P4 program is installed into the BMV2 software switch and your initial configuration is loaded. You can interact with the network using the mininet CLI below.

To inspect or change the switch configuration, connect to its CLI from your host operating system using this command: simple_switch_CLI --thrift-port

To view a switch log, run this command from your host OS: tail -f /home/fabtool/tutorials/P4D2_2017_Spring/exercises/ipv4_forward/build/logs/.log

To view the switch output pcap, check the pcap files in /home/fabtool/tutorials/P4D2_2017_Spring/exercises/ipv4_forward/build: for example run: sudo tcpdump -xxx -r s1-eth1.pcap

*** Starting CLI: mininet>

[antoninbas]

This stuff seems to be gone from the tutorials repo now. I don't think there is a convenient way to do it by modifying p4app.json so you may have to edit the p4apprunner.py script to add the --debugger command-line flag to the list of simple_switch args.

[djshah19]

Could you please show me where can I add the --debugger command-line flag in p4apprunner.py script

Here is the script:

from future import print_function

import argparse from collections import OrderedDict import json import os import sys import tarfile

parser = argparse.ArgumentParser(description='p4apprunner') parser.add_argument('--build-dir', help='Directory to build in.', type=str, action='store', required=False, default='/tmp') parser.add_argument('--quiet', help='Suppress log messages.', action='store_true', required=False, default=False) parser.add_argument('--manifest', help='Path to manifest file.', type=str, action='store', required=False, default='./p4app.json') parser.add_argument('app', help='.p4app package to run.', type=str) parser.add_argument('target', help=('Target to run. Defaults to the first target ' 'in the package.'), nargs='?', type=str)

args = parser.parse_args()

def log(items): if args.quiet != True: print(items)

def log_error(items): print(items, file=sys.stderr)

def run_command(command): log('>', command) return os.WEXITSTATUS(os.system(command))

class Manifest: def init(self, program_file, language, target, target_config): self.program_file = program_file self.language = language self.target = target self.target_config = target_config

def read_manifest(manifest_file): manifest = json.load(manifest_file, object_pairs_hook=OrderedDict)

if 'program' not in manifest:
    log_error('No program defined in manifest.')
    sys.exit(1)
program_file = manifest['program']

if 'language' not in manifest:
    log_error('No language defined in manifest.')
    sys.exit(1)
language = manifest['language']

if 'targets' not in manifest or len(manifest['targets']) < 1:
    log_error('No targets defined in manifest.')
    sys.exit(1)

if args.target is not None:
    chosen_target = args.target
elif 'default-target' in manifest:
    chosen_target = manifest['default-target']
else:
    chosen_target = manifest['targets'].keys()[0]

if chosen_target not in manifest['targets']:
    log_error('Target not found in manifest:', chosen_target)
    sys.exit(1)

return Manifest(program_file, language, chosen_target, manifest['targets'][chosen_target])

def run_compile_bmv2(manifest): if 'run-before-compile' in manifest.target_config: commands = manifest.target_config['run-before-compile'] if not isinstance(commands, list): log_error('run-before-compile should be a list:', commands) sys.exit(1) for command in commands: run_command(command)

compiler_args = []

if manifest.language == 'p4-14':
    compiler_args.append('--p4v 14')
elif manifest.language == 'p4-16':
    compiler_args.append('--p4v 16')
else:
    log_error('Unknown language:', manifest.language)
    sys.exit(1)

if 'compiler-flags' in manifest.target_config:
    flags = manifest.target_config['compiler-flags']
    if not isinstance(flags, list):
        log_error('compiler-flags should be a list:', flags)
        sys.exit(1)
    compiler_args.extend(flags)

# Compile the program.
output_file = manifest.program_file + '.json'
compiler_args.append('"%s"' % manifest.program_file)
compiler_args.append('-o "%s"' % output_file)
rv = run_command('p4c-bm2-ss %s' % ' '.join(compiler_args))

if 'run-after-compile' in manifest.target_config:
    commands = manifest.target_config['run-after-compile']
    if not isinstance(commands, list):
        log_error('run-after-compile should be a list:', commands)
        sys.exit(1)
    for command in commands:
        run_command(command)

if rv != 0:
    log_error('Compile failed.')
    sys.exit(1)

return output_file

def run_mininet(manifest): output_file = run_compile_bmv2(manifest)

# Run the program using the BMV2 Mininet simple switch.
switch_args = []

# We'll place the switch's log file in current (build) folder.
cwd = os.getcwd()
log_file = os.path.join(cwd, manifest.program_file + '.log')
print ("*** Log file %s" % log_file)
switch_args.append('--log-file "%s"' % log_file)

pcap_dir = os.path.join(cwd)
print ("*** Pcap folder %s" % pcap_dir)
switch_args.append('--pcap-dump "%s" '% pcap_dir)

# Generate a message that will be printed by the Mininet CLI to make
# interacting with the simple switch a little easier.
message_file = 'mininet_message.txt'
with open(message_file, 'w') as message:

    print(file=message)
    print('======================================================================',
          file=message)
    print('Welcome to the BMV2 Mininet CLI!', file=message)
    print('======================================================================',
          file=message)
    print('Your P4 program is installed into the BMV2 software switch', file=message)
    print('and your initial configuration is loaded. You can interact', file=message)
    print('with the network using the mininet CLI below.', file=message)
    print(file=message)
    print('To inspect or change the switch configuration, connect to', file=message)
    print('its CLI from your host operating system using this command:', file=message)
    print('  simple_switch_CLI', file=message)
    print(file=message)
    print('To view the switch log, run this command from your host OS:', file=message)
    print('  tail -f %s' %  log_file, file=message)
    print(file=message)
    print('To view the switch output pcap, check the pcap files in %s:' % pcap_dir, file=message)
    print(' for example run:  sudo tcpdump -xxx -r s1-eth1.pcap', file=message)
    print(file=message)

print('To run the switch debugger, run this command from your host OS:', file=message)

print(' bm_p4dbg' , file=message)

print(file=message)

switch_args.append('--cli-message "%s"' % message_file)

if 'num-hosts' in manifest.target_config:
    switch_args.append('--num-hosts %s' % manifest.target_config['num-hosts'])

if 'switch-config' in manifest.target_config:
    switch_args.append('--switch-config "%s"' % manifest.target_config['switch-config'])

switch_args.append('--behavioral-exe "%s"' % 'simple_switch')
switch_args.append('--json "%s"' % output_file)

program = '"%s/mininet/single_switch_mininet.py"' % sys.path[0]
return run_command('python2 %s %s' % (program, ' '.join(switch_args)))

def run_multiswitch(manifest): output_file = run_compile_bmv2(manifest)

script_args = []
cwd = os.getcwd()
log_dir = os.path.join(cwd, cwd + '/logs')
print ("*** Log directory %s" % log_dir)
script_args.append('--log-dir "%s"' % log_dir)
pcap_dir = os.path.join(cwd)
print ("*** Pcap directory %s" % cwd)
script_args.append('--manifest "%s"' % args.manifest)
script_args.append('--target "%s"' % manifest.target)
if 'auto-control-plane' in manifest.target_config and manifest.target_config['auto-control-plane']:
    script_args.append('--auto-control-plane' )
script_args.append('--behavioral-exe "%s"' % 'simple_switch')
script_args.append('--json "%s"' % output_file)
#script_args.append('--cli')

# Generate a message that will be printed by the Mininet CLI to make
# interacting with the simple switch a little easier.
message_file = 'mininet_message.txt'
with open(message_file, 'w') as message:

    print(file=message)
    print('======================================================================',
          file=message)
    print('Welcome to the BMV2 Mininet CLI!', file=message)
    print('======================================================================',
          file=message)
    print('Your P4 program is installed into the BMV2 software switch', file=message)
    print('and your initial configuration is loaded. You can interact', file=message)
    print('with the network using the mininet CLI below.', file=message)
    print(file=message)
    print('To inspect or change the switch configuration, connect to', file=message)
    print('its CLI from your host operating system using this command:', file=message)
    print('  simple_switch_CLI --thrift-port <switch thrift port>', file=message)
    print(file=message)
    print('To view a switch log, run this command from your host OS:', file=message)
    print('  tail -f %s/<switchname>.log' %  log_dir, file=message)
    print(file=message)
    print('To view the switch output pcap, check the pcap files in %s:' % pcap_dir, file=message)
    print(' for example run:  sudo tcpdump -xxx -r s1-eth1.pcap', file=message)
    print(file=message)

print('To run the switch debugger, run this command from your host OS:', file=message)

print(' bm_p4dbg' , file=message)

print(file=message)

script_args.append('--cli-message "%s"' % message_file)

program = '"%s/mininet/multi_switch_mininet.py"' % sys.path[0]
return run_command('python2 %s %s' % (program, ' '.join(script_args)))

def run_stf(manifest): output_file = run_compile_bmv2(manifest)

if not 'test' in manifest.target_config:
    log_error('No STF test file provided.')
    sys.exit(1)
stf_file = manifest.target_config['test']

# Run the program using the BMV2 STF interpreter.
stf_args = []
stf_args.append('-v')
stf_args.append(os.path.join(args.build_dir, output_file))
stf_args.append(os.path.join(args.build_dir, stf_file))

program = '"%s/stf/bmv2stf.py"' % sys.path[0]
rv = run_command('python2 %s %s' % (program, ' '.join(stf_args)))
if rv != 0:
    sys.exit(1)
return rv

def run_custom(manifest): output_file = run_compile_bmv2(manifest) python_path = 'PYTHONPATH=$PYTHONPATH:/scripts/mininet/'
script_args = [] script_args.append('--behavioral-exe "%s"' % 'simple_switch') script_args.append('--json "%s"' % output_file) script_args.append('--cli "%s"' % 'simple_switch_CLI') if not 'program' in manifest.target_config: log_error('No mininet program file provided.') sys.exit(1) program = manifest.target_config['program'] rv = run_command('%s python2 %s %s' % (python_path, program, ' '.join(script_args)))

if rv != 0:
    sys.exit(1)
return rv

def main(): log('Entering build directory.') os.chdir(args.build_dir)

# A '.p4app' package is really just a '.tar.gz' archive. Extract it so we
# can process its contents.
log('Extracting package.')
tar = tarfile.open(args.app)
tar.extractall()
tar.close()

log('Reading package manifest.')
with open(args.manifest, 'r') as manifest_file:
    manifest = read_manifest(manifest_file)

# Dispatch to the backend implementation for this target.
backend = manifest.target
if 'use' in manifest.target_config:
    backend = manifest.target_config['use']

if backend == 'mininet':
    rc = run_mininet(manifest)
elif backend == 'multiswitch':
    rc = run_multiswitch(manifest)
elif backend == 'stf':
    rc = run_stf(manifest)
elif backend == 'custom':
    rc = run_custom(manifest)
elif backend == 'compile-bmv2':
    run_compile_bmv2(manifest)
    rc = 0
else:
    log_error('Target specifies unknown backend:', backend)
    sys.exit(1)

sys.exit(rc)

if name == 'main': main()

[antoninbas]

You can probably just add it to the switch_args list

[djshah19]

Im still not able to enable debugger on switch. switch_args = ['--debugger'] is this correct place to add flag?

[djshah19]

I see below piece of code in p4_mininet.py
if self.enable_debugger: args.append("--debugger") if self.log_console: args.append("--log-console")

[djshah19]

I was able to start the debugger

Is it possible to open code in another box as shown in image below?

[antoninbas]

Everything that can be done with the debugger is included in the user guide (https://github.com/p4lang/behavioral-model/blob/master/docs/p4dbg_user_guide.md). That doesn't include displaying the code being executed (whether that's the P4 or the C++ code).

[afaheemp4]

@djshah19 Hello, Do you remember how the debugger problem solved by you?