Add an optional configuration file

A simple convenience configfile can provide a mapping between VPP
interface names, Linux Control Plane interface names, and descriptions.
An example:

```
interfaces:
  "TenGigabitEthernet6/0/0":
    description: "Infra: xsw0.chrma0:2"
    lcp: "xe1-0"
  "TenGigabitEthernet6/0/0.3102":
    description: "Infra: QinQ to Solnet for Daedalean"
    lcp: "xe1-0.3102"
  "TenGigabitEthernet6/0/0.310211":
    description: "Cust: Daedalean IP Transit"
    lcp: "xe1-0.3102.11"
```

This configuration file is completely optional. If the `-c` flag is
empty, or it's set but the file does not exist, the Agent will simply
enumerate all interfaces, and set the `ifAlias` OID to the same value
as the `ifName`. However, if the config file is read, it will change
the behavior as follows:

*  Any `tapNN` interface names from VPP will be matched to their PHY by
   looking up their Linux Control Plane interface. The `ifName` field
   will be rewritten to the _LIP_ `host-if`. For example, `tap3` above
   will become `xe1-0` while `tap3.310211` will become `xe1-0.3102.11`.
*  The `ifAlias` OID for a PHY will be set to the `description` field.
*  The `ifAlias` OID for a TAP will be set to the string `LCP: `
   followed by its PHY `ifName`. For example, `xe1-0.3102.11` will
    become `LCP TenGigabitEthernet6/0/0.310211 (tap9)`

README.md

@@ -36,12 +36,42 @@ optional arguments:
   -h, --help  show this help message and exit
   -a ADDRESS  Location of the SNMPd agent (unix-path or host:port), default localhost:705
   -p PERIOD   Period to poll VPP, default 30 (seconds)
+  -c CONFIG   Optional YAML configuration file, default empty
   -d          Enable debug, default False
 
 ## Install
 sudo cp dist/vpp-snmp-agent /usr/sbin/
 ```
 
+## Configuration file
+
+A simple convenience configfile can provide a mapping between VPP interface names, Linux Control Plane
+interface names, and descriptions. An example:
+
+```
+interfaces:
+  "TenGigabitEthernet6/0/0":
+    description: "Infra: xsw0.chrma0:2"
+    lcp: "xe1-0"
+  "TenGigabitEthernet6/0/0.3102":
+    description: "Infra: QinQ to Solnet for Daedalean"
+    lcp: "xe1-0.3102"
+  "TenGigabitEthernet6/0/0.310211":
+    description: "Cust: Daedalean IP Transit"
+    lcp: "xe1-0.3102.11"
+```
+
+This configuration file is completely optional. If the `-c` flag is empty, or it's set but the file does
+not exist, the Agent will simply enumerate all interfaces, and set the `ifAlias` OID to the same value as
+the `ifName`. However, if the config file is read, it will change the behavior as follows:
+
+*  Any `tapNN` interface names from VPP will be matched to their PHY by looking up their Linux Control Plane
+   interface. The `ifName` field will be rewritten to the _LIP_ `host-if`. For example, `tap3` above will
+   become `xe1-0` while `tap3.310211` will become `xe1-0.3102.11`.
+*  The `ifAlias` OID for a PHY will be set to the `description` field.
+*  The `ifAlias` OID for a TAP will be set to the string `LCP: ` followed by its PHY `ifName`. For example,
+   `xe1-0.3102.11` will become `LCP: TenGigabitEthernet6/0/0.310211 (tap9)`
+
 ## SNMPd config
 
 First, configure the snmpd to accept agentx connections by adding (at least) the following

agentx/network.py

@@ -97,7 +97,7 @@ class Network():
         self.socket.send(pdu.encode())
 
     def recv_pdu(self):
-        buf = self.socket.recv(8192)
+        buf = self.socket.recv(100000)
         if not buf: return None
         pdu = PDU()
         pdu.decode(buf)

vpp-snmp-agent.py

@@ -4,6 +4,7 @@
 from vppstats import VPPStats
 from vppapi import VPPApi
 import sys
+import yaml
 import agentx
 
 try:
@@ -12,10 +13,39 @@ except ImportError:
     print("ERROR: install argparse manually: sudo pip install argparse")
     sys.exit(2)
 
+def get_phy_by_sw_if_index(ifaces, sw_if_index):
+    try:
+        for k,v in ifaces.items():
+            if v.sw_if_index == sw_if_index:
+                return v
+    except:
+        pass
+    return None
+
+
+def get_lcp_by_host_sw_if_index(lcp, host_sw_if_index):
+    try:
+        for k,v in lcp.items():
+            if v['host_sw_if_index'] == host_sw_if_index:
+                return v
+    except:
+        pass
+    return None
+
 
 class MyAgent(agentx.Agent):
     def setup(self):
-        global vppstat, vpp, logger
+        global vppstat, vpp, logger, args
+
+        self.config = None
+        if args.config:
+            try:
+                with open(args.config, "r") as f:
+                    self.logger.info("Loading configfile %s" % args.config)
+                    self.config = yaml.load(f, Loader = yaml.FullLoader)
+                    self.logger.debug("Config: %s" % self.config)
+            except:
+                self.logger.error("Couldn't read config from %s" % args.config)
 
         self.logger.info("Connecting to VPP Stats Segment")
         vppstat = VPPStats(socketname='/run/vpp/stats.sock', timeout=2)
@@ -41,15 +71,45 @@ class MyAgent(agentx.Agent):
 
         ds = agentx.DataSet()
         ifaces = vpp.get_ifaces()
-        self.logger.debug("%d VPP interfaces retrieved" % len(ifaces))
+        lcp = vpp.get_lcp()
-        self.logger.debug("%d VPP Stats interfaces retrieved" % len(vppstat['/if/names']))
+        num_ifaces=len(ifaces)
+        num_vppstat=len(vppstat['/if/names'])
+        num_lcp=len(lcp)
+        self.logger.debug("LCP: %s" % (lcp))
+        self.logger.debug("Retrieved Interfaces: vppapi=%d vppstats=%d lcp=%d" % (num_ifaces, num_vppstat, num_lcp))
+
+        if num_ifaces != num_vppstat:
+            self.logger.error("Disconnecting due to error: vppapi=%d vppstats=%d" % (num_ifaces, num_vppstat))
+            vpp.disconnect()
+            vppstat.disconnect()
+            return False
+
 
         for i in range(len(vppstat['/if/names'])):
             ifname = vppstat['/if/names'][i]
             idx = 1000+i
 
             ds.set('1.3.6.1.2.1.2.2.1.1.%u' % (idx), 'int', idx)
-            ds.set('1.3.6.1.2.1.2.2.1.2.%u' % (idx), 'str', ifname)
+
+            ifName=ifname
+            ifAlias=None
+            try:
+                if self.config and ifname.startswith('tap'):
+                    host_sw_if_index = ifaces[ifname].sw_if_index
+                    lip = get_lcp_by_host_sw_if_index(lcp, host_sw_if_index)
+                    if lip:
+                        phy = get_phy_by_sw_if_index(ifaces, lip['phy_sw_if_index'])
+                        self.logger.debug("LIP: %s PHY: %s" % (lip, phy))
+                        if phy:
+                            ifName = self.config['interfaces'][phy.interface_name]['lcp']
+                            self.logger.debug("Setting ifName of %s to '%s'" % (ifname, ifName))
+                            ifAlias = "LCP %s (%s)" % (phy.interface_name,ifname)
+                            self.logger.debug("Setting ifAlias of %s to '%s'" % (ifname, ifAlias))
+            except:
+                self.logger.debug("No config entry found for ifname %s" % (ifname))
+                pass
+
+            ds.set('1.3.6.1.2.1.2.2.1.2.%u' % (idx), 'str', ifName)
 
             if ifname.startswith("loop"):
                 ds.set('1.3.6.1.2.1.2.2.1.3.%u' % (idx), 'int', 24)  # softwareLoopback
@@ -114,7 +174,7 @@ class MyAgent(agentx.Agent):
             ds.set('1.3.6.1.2.1.2.2.1.19.%u' % (idx), 'u32', vppstat['/if/drops'][:, i].sum() % 2**32)
             ds.set('1.3.6.1.2.1.2.2.1.20.%u' % (idx), 'u32', vppstat['/if/tx-error'][:, i].sum() % 2**32)
 
-            ds.set('1.3.6.1.2.1.31.1.1.1.1.%u' % (idx), 'str', ifname)
+            ds.set('1.3.6.1.2.1.31.1.1.1.1.%u' % (idx), 'str', ifName)
             ds.set('1.3.6.1.2.1.31.1.1.1.2.%u' % (idx), 'u32', vppstat['/if/rx-multicast'][:, i].sum_packets() % 2**32)
             ds.set('1.3.6.1.2.1.31.1.1.1.3.%u' % (idx), 'u32', vppstat['/if/rx-broadcast'][:, i].sum_packets() % 2**32)
             ds.set('1.3.6.1.2.1.31.1.1.1.4.%u' % (idx), 'u32', vppstat['/if/tx-multicast'][:, i].sum_packets() % 2**32)
@@ -141,14 +201,26 @@ class MyAgent(agentx.Agent):
 
             ds.set('1.3.6.1.2.1.31.1.1.1.16.%u' % (idx), 'int', 2)   # Hardcode to false(2)
             ds.set('1.3.6.1.2.1.31.1.1.1.17.%u' % (idx), 'int', 1)   # Hardcode to true(1)
-            ds.set('1.3.6.1.2.1.31.1.1.1.18.%u' % (idx), 'str', ifname)
+
+            if self.config and not ifAlias:
+                try:
+                    ifAlias = self.config['interfaces'][ifname]['description']
+                    self.logger.debug("Setting ifAlias of %s to '%s'" % (ifname, ifAlias))
+                except:
+                    pass
+            if not ifAlias:
+                ifAlias = ifname
+            ds.set('1.3.6.1.2.1.31.1.1.1.18.%u' % (idx), 'str', ifAlias)
             ds.set('1.3.6.1.2.1.31.1.1.1.19.%u' % (idx), 'ticks', 0)  # Hardcode to Timeticks: (0) 0:00:00.00
         return ds
 
 def main():
+    global args
+
     parser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter)
     parser.add_argument('-a', dest='address', default="localhost:705", type=str, help="""Location of the SNMPd agent (unix-path or host:port), default localhost:705""")
     parser.add_argument('-p', dest='period', type=int, default=30, help="""Period to poll VPP, default 30 (seconds)""")
+    parser.add_argument('-c', dest='config', type=str, help="""Optional YAML configuration file, default empty""")
     parser.add_argument('-d', dest='debug', action='store_true', help="""Enable debug, default False""")
 
     args = parser.parse_args()

vpp-snmp-agent.service

@@ -6,7 +6,7 @@ ConditionPathExists=/etc/snmp/snmpd.conf
 [Service]
 Type=simple
 NetworkNamespacePath=/var/run/netns/dataplane
-ExecStart=/usr/sbin/vpp-snmp-agent -a localhost:705 -p 30
+ExecStart=/usr/sbin/vpp-snmp-agent -a localhost:705 -p 30 -c /etc/vpp/vpp-snmp-agent.yaml
 User=Debian-snmp
 Group=vpp
 ExecReload=/bin/kill -HUP $MAINPID

vpp-snmp-agent.yaml

@@ -0,0 +1,14 @@
+## Example configuration file for VPP SNMP Agent
+##
+## See README.md for details on what this (optional) file does.
+
+interfaces:
+  "GigabitEthernet5/0/0":
+    description: "Infra: xsw0.chrma0.ipng.ch Te0/2"
+    lcp: "e0"
+  "GigabitEthernet5/0/0.3102":
+    description: "Infra: QinQ to L2 Provider"
+    lcp: "e0.3102"
+  "GigabitEthernet5/0/0.310211":
+    description: "Cust: Downstream IP Transit"
+    lcp: "e0.3102.11"

vppapi.py

@@ -7,6 +7,7 @@ from vpp_papi import VPPApiClient
 import os
 import fnmatch
 import logging
+import socket
 
 
 class NullHandler(logging.Handler):
@@ -81,3 +82,45 @@ class VPPApi():
             ret[iface.interface_name] = iface
 
         return ret
+
+    def get_lcp(self):
+        ret = {}
+        if not self.connected:
+            return ret
+
+
+        try:
+            lcp_list = self.vpp.api.lcp_itf_pair_get()
+        except Exception as e:
+            logger.error("VPP communication error, disconnecting", e)
+            self.vpp.disconnect()
+            self.connected = False
+            return ret
+
+        if not lcp_list or not lcp_list[1]:
+            logger.error("Can't get LCP list")
+            return ret
+
+        ## TODO(pim) - fix upstream, the indexes are in network byte order and
+        ## the message is messed up. This hack allows for both little endian and
+        ## big endian responses, and will be removed once VPP's LinuxCP is updated
+        ## and rolled out to AS8298
+        for lcp in lcp_list[1]:
+            if lcp.phy_sw_if_index > 65535 or lcp.host_sw_if_index > 65535 or lcp.vif_index > 65535:
+                i = {
+                  'phy_sw_if_index': socket.ntohl(lcp.phy_sw_if_index),
+                  'host_sw_if_index': socket.ntohl(lcp.host_sw_if_index),
+                  'vif_index': socket.ntohl(lcp.vif_index),
+                  'host_if_name': lcp.host_if_name,
+                  'namespace': lcp.namespace
+                  }
+            else:
+                i = {
+                  'phy_sw_if_index': lcp.phy_sw_if_index,
+                  'host_sw_if_index': lcp.host_sw_if_index,
+                  'vif_index': lcp.vif_index,
+                  'host_if_name': lcp.host_if_name,
+                  'namespace': lcp.namespace
+                  }
+            ret[lcp.host_if_name] = i
+        return ret