1import os
2import subprocess
3import pyroute2
4from pyroute2 import IPRoute, NetNS, IPDB, NSPopen
5
6class Simulation(object):
7    """
8    Helper class for controlling multiple namespaces. Inherit from
9    this class and setup your namespaces.
10    """
11
12    def __init__(self, ipdb):
13        self.ipdb = ipdb
14        self.ipdbs = {}
15        self.namespaces = []
16        self.processes = []
17        self.released = False
18
19    # helper function to add additional ifc to namespace
20    # if called directly outside Simulation class, "ifc_base_name" should be
21    # different from "name", the "ifc_base_name" and "name" are the same for
22    # the first ifc created by namespace
23    def _ns_add_ifc(self, name, ns_ifc, ifc_base_name=None, in_ifc=None,
24                    out_ifc=None, ipaddr=None, macaddr=None, fn=None, cmd=None,
25                    action="ok", disable_ipv6=False):
26        if name in self.ipdbs:
27            ns_ipdb = self.ipdbs[name]
28        else:
29            try:
30                nl=NetNS(name)
31                self.namespaces.append(nl)
32            except KeyboardInterrupt:
33                # remove the namespace if it has been created
34                pyroute2.netns.remove(name)
35                raise
36            ns_ipdb = IPDB(nl)
37            self.ipdbs[nl.netns] = ns_ipdb
38            if disable_ipv6:
39                cmd1 = ["sysctl", "-q", "-w",
40                       "net.ipv6.conf.default.disable_ipv6=1"]
41                nsp = NSPopen(ns_ipdb.nl.netns, cmd1)
42                nsp.wait(); nsp.release()
43            try:
44                ns_ipdb.interfaces.lo.up().commit()
45            except pyroute2.ipdb.exceptions.CommitException:
46                print("Warning, commit for lo failed, operstate may be unknown")
47        if in_ifc:
48            in_ifname = in_ifc.ifname
49            with in_ifc as v:
50                # move half of veth into namespace
51                v.net_ns_fd = ns_ipdb.nl.netns
52        else:
53            # delete the potentially leaf-over veth interfaces
54            ipr = IPRoute()
55            for i in ipr.link_lookup(ifname='%sa' % ifc_base_name): ipr.link("del", index=i)
56            ipr.close()
57            try:
58                out_ifc = self.ipdb.create(ifname="%sa" % ifc_base_name, kind="veth",
59                                           peer="%sb" % ifc_base_name).commit()
60                in_ifc = self.ipdb.interfaces[out_ifc.peer]
61                in_ifname = in_ifc.ifname
62                with in_ifc as v:
63                    v.net_ns_fd = ns_ipdb.nl.netns
64            except KeyboardInterrupt:
65                # explicitly remove the interface
66                out_ifname = "%sa" % ifc_base_name
67                if out_ifname in self.ipdb.interfaces: self.ipdb.interfaces[out_ifname].remove().commit()
68                raise
69
70        if out_ifc: out_ifc.up().commit()
71        try:
72            # this is a workaround for fc31 and possible other disto's.
73            # when interface 'lo' is already up, do another 'up().commit()'
74            # has issues in fc31.
75            # the workaround may become permanent if we upgrade pyroute2
76            # in all machines.
77            if 'state' in ns_ipdb.interfaces.lo.keys():
78                if ns_ipdb.interfaces.lo['state'] != 'up':
79                    ns_ipdb.interfaces.lo.up().commit()
80            else:
81                ns_ipdb.interfaces.lo.up().commit()
82        except pyroute2.ipdb.exceptions.CommitException:
83            print("Warning, commit for lo failed, operstate may be unknown")
84        ns_ipdb.initdb()
85        in_ifc = ns_ipdb.interfaces[in_ifname]
86        with in_ifc as v:
87            v.ifname = ns_ifc
88            if ipaddr: v.add_ip("%s" % ipaddr)
89            if macaddr: v.address = macaddr
90            v.up()
91        if disable_ipv6:
92            cmd1 = ["sysctl", "-q", "-w",
93                   "net.ipv6.conf.%s.disable_ipv6=1" % out_ifc.ifname]
94            subprocess.call(cmd1)
95        if fn and out_ifc:
96            self.ipdb.nl.tc("add", "ingress", out_ifc["index"], "ffff:")
97            self.ipdb.nl.tc("add-filter", "bpf", out_ifc["index"], ":1",
98                            fd=fn.fd, name=fn.name, parent="ffff:",
99                            action=action, classid=1)
100        if cmd:
101            self.processes.append(NSPopen(ns_ipdb.nl.netns, cmd))
102        return (ns_ipdb, out_ifc, in_ifc)
103
104    # helper function to create a namespace and a veth connecting it
105    def _create_ns(self, name, in_ifc=None, out_ifc=None, ipaddr=None,
106                   macaddr=None, fn=None, cmd=None, action="ok", disable_ipv6=False):
107        (ns_ipdb, out_ifc, in_ifc) = self._ns_add_ifc(name, "eth0", name, in_ifc, out_ifc,
108                                                      ipaddr, macaddr, fn, cmd, action,
109                                                      disable_ipv6)
110        return (ns_ipdb, out_ifc, in_ifc)
111
112    def release(self):
113        if self.released: return
114        self.released = True
115        for p in self.processes:
116            if p.released: continue
117            try:
118                p.kill()
119                p.wait()
120            except:
121                pass
122            finally:
123                p.release()
124        for name, db in self.ipdbs.items(): db.release()
125        for ns in self.namespaces: ns.remove()
126
127