adde source_routing exercise

SIGCOMM_2015/source_routing/send.py

@@ -0,0 +1,106 @@
+#!/usr/bin/python
+
+# Copyright 2013-present Barefoot Networks, Inc. 
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from scapy.all import sniff, sendp
+from scapy.all import Packet
+from scapy.all import ShortField, IntField, LongField, BitField
+
+import networkx as nx
+
+import sys
+
+class SrcRoute(Packet):
+    name = "SrcRoute"
+    fields_desc = [
+        LongField("preamble", 0),
+        IntField("num_valid", 0)
+    ]
+
+def read_topo():
+    nb_hosts = 0
+    nb_switches = 0
+    links = []
+    with open("topo.txt", "r") as f:
+        line = f.readline()[:-1]
+        w, nb_switches = line.split()
+        assert(w == "switches")
+        line = f.readline()[:-1]
+        w, nb_hosts = line.split()
+        assert(w == "hosts")
+        for line in f:
+            if not f: break
+            a, b = line.split()
+            links.append( (a, b) )
+    return int(nb_hosts), int(nb_switches), links
+
+def main():
+    if len(sys.argv) != 3:
+        print "Usage: send.py [this_host] [target_host]"
+        print "For example: send.py h1 h2"
+        sys.exit(1)
+
+    src, dst = sys.argv[1:]
+
+    nb_hosts, nb_switches, links = read_topo()
+
+    port_map = {}
+
+    for a, b in links:
+        if a not in port_map:
+            port_map[a] = {}
+        if b not in port_map:
+            port_map[b] = {}
+
+        assert(b not in port_map[a])
+        assert(a not in port_map[b])
+        port_map[a][b] = len(port_map[a]) + 1
+        port_map[b][a] = len(port_map[b]) + 1
+
+
+    G = nx.Graph()
+    for a, b in links:
+        G.add_edge(a, b)
+
+    shortest_paths = nx.shortest_path(G)
+    shortest_path = shortest_paths[src][dst]
+
+    print "path is:", shortest_path
+
+    port_list = []
+    first = shortest_path[1]
+    for h in shortest_path[2:]:
+        port_list.append(port_map[first][h])
+        first = h
+
+    print "port list is:", port_list
+
+    port_str = ""
+    for p in port_list:
+        port_str += chr(p)
+
+    while(1):
+        msg = raw_input("What do you want to send: ")
+
+        # finding the route
+        first = None
+
+        p = SrcRoute(num_valid = len(port_list)) / port_str / msg
+        print p.show()
+        sendp(p, iface = "eth0")
+        # print msg
+
+if __name__ == '__main__':
+    main()