commit b32d6fd187e78539e2f9c4415f478a2da80d7a0f Author: Arturo Filastò art@fuffa.org Date: Wed Feb 27 15:57:35 2013 +0100

Refactor logic for importing scapy related functions

* Make scapy related requirements less strict * Always print out a useful error message when something goes wrong (cherry picked from commit 77b2f6e7206f5a1bb1531fb2416eaf36675b098b) --- ooni/utils/net.py | 2 +- ooni/utils/txscapy.py | 54 ++++++++++++++++++++++++++++++++++++------------ 2 files changed, 41 insertions(+), 15 deletions(-)

diff --git a/ooni/utils/net.py b/ooni/utils/net.py index 49f9998..67a98c2 100644 --- a/ooni/utils/net.py +++ b/ooni/utils/net.py @@ -7,7 +7,7 @@ from twisted.internet import protocol, defer from twisted.internet import threads, reactor from twisted.web.iweb import IBodyProducer

-from ooni.utils import log, txscapy +from ooni.utils import log

#if sys.platform.system() == 'Windows': # import _winreg as winreg diff --git a/ooni/utils/txscapy.py b/ooni/utils/txscapy.py index 0e805e7..84e69a6 100644 --- a/ooni/utils/txscapy.py +++ b/ooni/utils/txscapy.py @@ -14,24 +14,50 @@ from scapy.config import conf from ooni.utils import log from ooni import config

-try: - conf.use_pcap = True - conf.use_dnet = True +class LibraryNotInstalledError(Exception): + pass

- from scapy.all import PcapWriter - from scapy.arch import pcapdnet +def pcapdnet_installed(): + """ + Checks to see if libdnet or libpcap are installed and set the according + variables.

- config.pcap_dnet = True - from scapy.all import Gen, SetGen, MTU + Returns:

-except ImportError, e: - log.err("pypcap or dnet not installed. " - "Certain tests may not work.") + True + if pypcap and libdnet are installed

- config.pcap_dnet = False - conf.use_pcap = False - conf.use_dnet = False + False + if one of the two is absent + """ + try: + conf.use_pcap = True + conf.use_dnet = True + from scapy.arch import pcapdnet + + config.pcap_dnet = True + + except ImportError: + log.err("pypcap or dnet not installed. " + "Certain tests may not work.") + + config.pcap_dnet = False + conf.use_pcap = False + conf.use_dnet = False + + # This is required for unix systems that are different than linux (OSX for + # example) since scapy explicitly wants pcap and libdnet installed for it + # to work. + try: + from scapy.arch import pcapdnet + except ImportError: + log.err("Your platform requires to having libdnet and libpcap installed.") + raise LibraryNotInstalledError + +if pcapdnet_installed(): + from scapy.all import PcapWriter

+else: class DummyPcapWriter: def __init__(self, pcap_filename, *arg, **kw): log.err("Initializing DummyPcapWriter. We will not actually write to a pcapfile") @@ -41,7 +67,7 @@ except ImportError, e:

PcapWriter = DummyPcapWriter

- from scapy.all import Gen, SetGen, MTU +from scapy.all import Gen, SetGen, MTU

def getNetworksFromRoutes(): """ Return a list of networks from the routing table """