Document Link parameters. Fix units. Add a couple more tests

src/netns/interface.py

@@ -360,6 +360,20 @@ class Link(ExternalInterface):
             loss = None, loss_correlation = None,
             dup = None, dup_correlation = None,
             corrupt = None, corrupt_correlation = None):
+        """Set the parameters that control the link characteristics. For the
+        description of each, refer to netem documentation:
+        http://www.linuxfoundation.org/collaborate/workgroups/networking/netem
+
+        Arguments:
+        - `bandwidth' should be specified in bits per second.
+        - `delay' and `delay_jitter' are specified in seconds.
+        - `delay_distribution' is the name of a distribution description file;
+          `iproute' comes by default with `normal', `pareto', and
+          `paretonormal'.
+        - `delay_correlation', `loss', `loss_correlation', `dup',
+          `dup_correlation', `corrupt', and `corrupt_correlation' take a
+          percentage value in the form of a number between 0 and 1. (50% is
+          passed as 0.5)."""
         parameters = dict(bandwidth = bandwidth,
                 delay = delay, delay_jitter = delay_jitter,
                 delay_correlation = delay_correlation,

src/netns/iproute.py

@@ -753,7 +753,7 @@ def _parse_netem_delay(line):
         ret["delay_jitter"] = delay_jitter
 
     if match.group(5):
-        ret["delay_correlation"] = float(match.group(5))
+        ret["delay_correlation"] = float(match.group(5)) / 100
 
     if match.group(6):
         ret["delay_distribution"] = match.group(6)
@@ -766,9 +766,9 @@ def _parse_netem_loss(line):
     if not match:
         return ret
 
-    ret["loss"] = float(match.group(1))
+    ret["loss"] = float(match.group(1)) / 100
     if match.group(2):
-        ret["loss_correlation"] = float(match.group(2))
+        ret["loss_correlation"] = float(match.group(2)) / 100
     return ret
 
 def _parse_netem_dup(line):
@@ -777,9 +777,9 @@ def _parse_netem_dup(line):
     if not match:
         return ret
 
-    ret["dup"] = float(match.group(1))
+    ret["dup"] = float(match.group(1)) / 100
     if match.group(2):
-        ret["dup_correlation"] = float(match.group(2))
+        ret["dup_correlation"] = float(match.group(2)) / 100
     return ret
 
 def _parse_netem_corrupt(line):
@@ -788,9 +788,9 @@ def _parse_netem_corrupt(line):
     if not match:
         return ret
 
-    ret["corrupt"] = float(match.group(1))
+    ret["corrupt"] = float(match.group(1)) / 100
     if match.group(2):
-        ret["corrupt_correlation"] = float(match.group(2))
+        ret["corrupt_correlation"] = float(match.group(2)) / 100
     return ret
 
 def get_tc_data():
@@ -888,7 +888,7 @@ def set_tc(iface, bandwidth = None, delay = None, delay_jitter = None,
         cmd = "add"
 
     if bandwidth:
-        rate = "%dbps" % int(bandwidth)
+        rate = "%dbit" % int(bandwidth)
         mtu = ifdata[iface.index].mtu
         burst = max(mtu, int(bandwidth) / _hz)
         limit = burst * 2 # FIXME?
@@ -918,23 +918,23 @@ def set_tc(iface, bandwidth = None, delay = None, delay_jitter = None,
             if delay_jitter:
                 command += ["%fs" % delay_jitter]
             if delay_correlation:
-                command += ["%f%%" % delay_correlation]
+                command += ["%f%%" % (delay_correlation * 100)]
             if delay_distribution:
                 if not delay_jitter: # or not delay_correlation:
                     raise ValueError("delay_distribution requires delay_jitter")
                 command += ["distribution", delay_distribution]
         if loss:
-            command += ["loss", "%f%%" % loss]
+            command += ["loss", "%f%%" % (loss * 100)]
             if loss_correlation:
-                command += ["%f%%" % loss_correlation]
+                command += ["%f%%" % (loss_correlation * 100)]
         if dup:
-            command += ["duplicate", "%f%%" % dup]
+            command += ["duplicate", "%f%%" % (dup * 100)]
             if dup_correlation:
-                command += ["%f%%" % dup_correlation]
+                command += ["%f%%" % (dup_correlation * 100)]
         if corrupt:
-            command += ["corrupt", "%f%%" % corrupt]
+            command += ["corrupt", "%f%%" % (corrupt * 100)]
             if corrupt_correlation:
-                command += ["%f%%" % corrupt_correlation]
+                command += ["%f%%" % (corrupt_correlation * 100)]
         commands.append(command)
 
     for c in commands:

t/test_link.py

@@ -32,13 +32,30 @@ class TestLink(unittest.TestCase):
         self.assertEquals(ifdata[i2.control.index].up, True, "UP propagation")
 
         # None => tbf
-        l.set_parameters(bandwidth = 100*1024*1024/8) # 100 mbits
+        l.set_parameters(bandwidth = 13107200) # 100 mbits
         tcdata = netns.iproute.get_tc_data()[0]
         self.assertEquals(tcdata[i1.control.index],
-                {'bandwidth': 104858000, 'qdiscs': {'tbf': '1'}})
+                # adjust for tc rounding
+                {'bandwidth': 13107000, 'qdiscs': {'tbf': '1'}})
         self.assertEquals(tcdata[i2.control.index],
-                {'bandwidth': 104858000, 'qdiscs': {'tbf': '1'}})
-        #bandwidth = 100*1024*1024/8, loss=10, loss_correlation=1,delay=0.001,dup_correlation=0.1); 
+                {'bandwidth': 13107000, 'qdiscs': {'tbf': '1'}})
+
+        # none again
+        l.set_parameters()
+        tcdata = netns.iproute.get_tc_data()[0]
+        self.assertEquals(tcdata[i1.control.index], {'qdiscs': {}})
+        self.assertEquals(tcdata[i2.control.index], {'qdiscs': {}})
+
+        # cheat and see what happens
+        os.system(("tc qd add dev %s root prio bands 3 " +
+            "priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1") % i1.control.name)
+        tcdata = netns.iproute.get_tc_data()[0]
+        self.assertEquals(tcdata[i1.control.index], "foreign")
+        l.set_parameters(bandwidth = 13107200) # 100 mbits
+        tcdata = netns.iproute.get_tc_data()[0]
+        self.assertEquals(tcdata[i1.control.index],
+                {'bandwidth': 13107000, 'qdiscs': {'tbf': '1'}})
+
         # FIXME: more cases
 
 if __name__ == '__main__':