From: Brian Warner Date: Thu, 8 Mar 2007 03:03:47 +0000 (-0700) Subject: iputil: switch to a scapy-inspired SIOCGIFADDR approach, very linux-specific now X-Git-Url: https://git.rkrishnan.org/components/com_hotproperty/frontends/%3C?a=commitdiff_plain;h=751587f3766df6e26d37bceda698e820688a7484;p=tahoe-lafs%2Ftahoe-lafs.git iputil: switch to a scapy-inspired SIOCGIFADDR approach, very linux-specific now --- diff --git a/src/allmydata/util/iputil.py b/src/allmydata/util/iputil.py index f41b3dcd..83791416 100644 --- a/src/allmydata/util/iputil.py +++ b/src/allmydata/util/iputil.py @@ -9,9 +9,55 @@ from twisted.internet import reactor from twisted.internet.protocol import DatagramProtocol from twisted.internet.utils import getProcessOutput +from fcntl import ioctl +import struct +SIOCGIFADDR = 0x8915 # linux-specific + +# inspired by scapy +def get_if_list(): + f = open("/proc/net/dev","r") + f.readline(); f.readline() + names = [] + for l in f.readlines(): + names.append(l[:l.index(":")].strip()) + return names + +def get_if_addr(ifname): + try: + s=socket.socket() + ifreq = ioctl(s, SIOCGIFADDR, struct.pack("16s16x", ifname)) + s.close() + naddr = ifreq[20:24] + return socket.inet_ntoa(naddr) + except IOError: + return None + def get_local_addresses(): - """Return a Deferred that fires with a list of IPv4 addresses (as - dotted-quad strings) that are currently configured on this host. + """Return a list of IPv4 addresses (as dotted-quad strings) that are + currently configured on this host. + + This will only work under linux, because it uses both a linux-specific + /proc/net/dev devices (to get the interface names) and a SIOCGIFADDR + ioctl (to get their addresses). If the listing-the-interfaces were done + with an ioctl too (and if if you're lucky enough to be using the same + value for the ioctls), then it might work on other forms of unix too. + Windows is right out.""" + + ifnames = [] + for ifname in get_if_list(): + addr = get_if_addr(ifname) + if addr: + ifnames.append(addr) + return ifnames + +def get_local_addresses_sync(): + """Return a list of IPv4 addresses (as dotted-quad strings) that are + currently configured on this host. + + Unfortunately this is not compatible with Twisted: it catches SIGCHLD and + this usually results in errors about 'Interrupted system call'. + + This will probably work on both linux and OS-X, but probably not windows. """ # eventually I want to use somebody else's cross-platform library for # this. For right now, I'm running ifconfig and grepping for the 'inet ' @@ -34,6 +80,8 @@ def get_local_addresses(): def get_local_addresses_async(): """Return a Deferred that fires with a list of IPv4 addresses (as dotted-quad strings) that are currently configured on this host. + + This will probably work on both linux and OS-X, but probably not windows. """ # eventually I want to use somebody else's cross-platform library for # this. For right now, I'm running ifconfig and grepping for the 'inet '