added a counter example

examples/README.md

@@ -12,6 +12,7 @@ included:
 - `TLV_parsing`: how to parse IPv4 options
 - `register`: how to use registers in P4 and read / write the state from the
   control plane
+- `counter`: how to use counters in P4
 
 All examples are orgranized the same way, with a `p4src` directory containing
 the P4 source code, and a `README` file describing the P4 program and explaining

examples/counter/README.md

@@ -0,0 +1,14 @@
+# Counter
+
+## Description
+
+This directory is a playground for counters in P4. The P4 program includes a
+direct counter and an indirect counter.
+
+### Running the demo
+
+To run the demo:
+- start the switch with `./run_switch.sh`, wait until `READY` is displayed.
+- run the demo script with `./run_demo.sh`. The script will send packets /
+  display the counter values / reset the counters. Look at the script for more
+  details.

examples/counter/commands.txt

@@ -0,0 +1,2 @@
+table_set_default m_table m_action
+table_add m_table m_action aa:bb:cc:dd:ee:ff => 0

examples/counter/p4src/counter.p4

@@ -0,0 +1,92 @@
+/*
+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.
+*/
+
+header_type ethernet_t {
+    fields {
+        dstAddr : 48;
+        srcAddr : 48;
+        etherType : 16;
+    }
+}
+
+header_type intrinsic_metadata_t {
+    fields {
+        mcast_grp : 4;
+        egress_rid : 4;
+        mcast_hash : 16;
+        lf_field_list: 32;
+    }
+}
+
+header_type meta_t {
+    fields {
+        register_tmp : 32;
+    }
+}
+
+metadata meta_t meta;
+
+parser start {
+    return parse_ethernet;
+}
+
+header ethernet_t ethernet;
+metadata intrinsic_metadata_t intrinsic_metadata;
+
+parser parse_ethernet {
+    extract(ethernet);
+    return ingress;
+}
+
+action _drop() {
+    drop();
+}
+
+action _nop() {
+}
+
+counter my_indirect_counter {
+    type: packets;
+    static: m_table;
+    instance_count: 16384;
+}
+
+counter my_direct_counter {
+    type: bytes;
+    direct: m_table;
+}
+
+action m_action(idx) {
+    count(my_indirect_counter, idx);
+    drop();
+}
+
+table m_table {
+    reads {
+        ethernet.srcAddr : exact;
+    }
+    actions {
+        m_action; _nop;
+    }
+    size : 16384;
+}
+
+control ingress {
+    apply(m_table);
+}
+
+control egress {
+}

examples/counter/run_demo.sh

@@ -0,0 +1,63 @@
+#!/bin/bash
+
+# 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.
+
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+
+source $THIS_DIR/../env.sh
+
+CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
+
+echo "resetting counters"
+echo "counter_reset my_indirect_counter" | $CLI_PATH counter.json
+echo "counter_reset my_direct_counter" | $CLI_PATH counter.json
+echo
+echo
+echo
+echo "displaying counters [0]"
+echo "counter_read my_indirect_counter 0" | $CLI_PATH counter.json
+echo "counter_read my_direct_counter 0" | $CLI_PATH counter.json
+echo
+echo
+echo
+echo "sending 1 packet of size 70"
+sudo python send_one.py
+sleep 1
+echo
+echo
+echo
+echo "displaying counters [0]"
+echo "counter_read my_indirect_counter 0" | $CLI_PATH counter.json
+echo "counter_read my_direct_counter 0" | $CLI_PATH counter.json
+echo
+echo
+echo
+echo "sending 3 packets of size 70"
+sudo python send_one.py
+sudo python send_one.py
+sudo python send_one.py
+sleep 1
+echo
+echo
+echo
+echo "displaying counters [0]"
+echo "counter_read my_indirect_counter 0" | $CLI_PATH counter.json
+echo "counter_read my_direct_counter 0" | $CLI_PATH counter.json
+echo
+echo
+echo
+echo "resetting counters"
+echo "counter_reset my_indirect_counter" | $CLI_PATH counter.json
+echo "counter_reset my_direct_counter" | $CLI_PATH counter.json

examples/counter/run_switch.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+# 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.
+
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+
+source $THIS_DIR/../env.sh
+
+P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
+
+SWITCH_PATH=$BMV2_PATH/targets/simple_switch/simple_switch
+
+CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
+
+# Probably not very elegant but it works nice here: we enable interactive mode
+# to be able to use fg. We start the switch in the background, sleep for 2
+# minutes to give it time to start, then add the entries and put the switch
+# process back in the foreground
+set -m
+$P4C_BM_SCRIPT p4src/counter.p4 --json counter.json
+sudo echo "sudo" > /dev/null
+sudo $BMV2_PATH/targets/simple_switch/simple_switch counter.json \
+    -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
+    --nanolog ipc:///tmp/bm-0-log.ipc \
+    --pcap &
+sleep 2
+$CLI_PATH counter.json < commands.txt
+echo "READY!!!"
+fg

examples/counter/send_one.py

@@ -0,0 +1,4 @@
+from scapy.all import *
+
+p = Ether(src="aa:bb:cc:dd:ee:ff") / IP(dst="10.0.1.10") / TCP() / "aaaaaaaaaaaaaaaa"
+sendp(p, iface = "veth1", verbose = 0)