Merge pull request #8 from p4lang/workshop-05-16

added ECMP exercise for May 2016 P4 workshop

.gitignore

@@ -10,4 +10,4 @@
 *.pcap
 
 # Extracted solutions
-solution/
+solution*/

SIGCOMM_2015/README.md

@@ -80,9 +80,9 @@ like this:
 
 You need to tell us where you cloned the `bmv2` and `p4c-bm` repositories
 :). Please update the values of the shell variables `BMV2_PATH` and
-`P4C_BM_PATH` in the `env.sh` file - located in this directory. Note that if you
+`P4C_BM_PATH` in the `env.sh` file - located in the root directory of this
-cloned both repositories in the same directory as this one (`tutorials`), you
+repository. Note that if you cloned both repositories in the same directory as
-will not need to change the value of the variables.
+this one (`tutorials`), you will not need to change the value of the variables.
 
 That's all :)
 

SIGCOMM_2015/flowlet_switching/run_demo.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/tools/runtime_CLI.py
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/simple_router.p4 --json simple_router.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch simple_router.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH simple_router.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap &

SIGCOMM_2015/source_routing/run_demo.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -25,7 +25,9 @@ SWITCH_PATH=$BMV2_PATH/targets/simple_switch/simple_switch
 CLI_PATH=$BMV2_PATH/tools/runtime_CLI.py
 
 $P4C_BM_SCRIPT p4src/source_routing.p4 --json source_routing.json
+# This gives libtool the opportunity to "warm-up"
+sudo $SWITCH_PATH >/dev/null 2>&1
 sudo PYTHONPATH=$PYTHONPATH:$BMV2_PATH/mininet/ python topo.py \
-    --behavioral-exe $BMV2_PATH/targets/simple_switch/simple_switch \
+    --behavioral-exe $SWITCH_PATH \
     --json source_routing.json \
     --cli $CLI_PATH

env.sh

@@ -1,8 +1,8 @@
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
 # ---------------- EDIT THIS ------------------
-BMV2_PATH=$THIS_DIR/../../bmv2
+BMV2_PATH=$THIS_DIR/../bmv2
 # e.g. BMV2_PATH=$THIS_DIR/../bmv2
-P4C_BM_PATH=$THIS_DIR/../../p4c-bmv2
+P4C_BM_PATH=$THIS_DIR/../p4c-bmv2
 # e.g P4C_BM_PATH=$THIS_DIR/../p4c-bm
 # ---------------- END ------------------

examples/.gitignore

@@ -1,10 +0,0 @@
-# Python byte code
-*.pyc
-
-# Emacs
-*~
-
-# Compiled JSON
-*.json
-
-*.pcap

examples/README.md

@@ -55,9 +55,9 @@ build the code once all the dependencies have been installed:
 
 You need to tell us where you cloned the `bmv2` and `p4c-bm` repositories
 :). Please update the values of the shell variables `BMV2_PATH` and
-`P4C_BM_PATH` in the `env.sh` file - located in this directory. Note that if you
+`P4C_BM_PATH` in the `env.sh` file - located in the root directory of this
-cloned both repositories in the same directory as this one (`tutorials`), you
+repository. Note that if you cloned both repositories in the same directory as
-will not need to change the value of the variables.
+this one (`tutorials`), you will not need to change the value of the variables.
 
 You will also need to run the `veth_setup.sh` script included in this directory
 as `sudo` to setup the veth interfaces needed by the switch.

examples/TLV_parsing/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/TLV_parsing.p4 --json TLV_parsing.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch TLV_parsing.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH TLV_parsing.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap &

examples/action_profile/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/action_profile.p4 --json action_profile.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch action_profile.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH action_profile.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap &

examples/axon/run_demo.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -25,7 +25,9 @@ SWITCH_PATH=$BMV2_PATH/targets/simple_switch/simple_switch
 CLI_PATH=$BMV2_PATH/tools/runtime_CLI.py
 
 $P4C_BM_SCRIPT p4src/axon.p4 --json axon.json
+# This gives libtool the opportunity to "warm-up"
+sudo $SWITCH_PATH >/dev/null 2>&1
 sudo PYTHONPATH=$PYTHONPATH:$BMV2_PATH/mininet/ python topo.py \
-    --behavioral-exe $BMV2_PATH/targets/simple_switch/simple_switch \
+    --behavioral-exe $SWITCH_PATH \
     --json axon.json \
     --cli $CLI_PATH

examples/copy_to_cpu/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/copy_to_cpu.p4 --json copy_to_cpu.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch copy_to_cpu.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH copy_to_cpu.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap &

examples/counter/run_demo.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 

examples/counter/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/counter.p4 --json counter.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch counter.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH 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 &

examples/env.sh

@@ -1,8 +0,0 @@
-THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
-
-# ---------------- EDIT THIS ------------------
-BMV2_PATH=$THIS_DIR/../../bmv2
-# e.g. BMV2_PATH=$THIS_DIR/../bmv2
-P4C_BM_PATH=$THIS_DIR/../../p4c-bmv2
-# e.g P4C_BM_PATH=$THIS_DIR/../p4c-bm
-# ---------------- END ------------------

examples/meter/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/meter.p4 --json meter.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch meter.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH meter.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap &

examples/register/read_register.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 

examples/register/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/register.p4 --json register.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch register.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH register.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc \
     --pcap

examples/register/write_register.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 

examples/resubmit/run_switch.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -30,8 +30,9 @@ CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 # process back in the foreground
 set -m
 $P4C_BM_SCRIPT p4src/resubmit.p4 --json resubmit.json
-sudo echo "sudo" > /dev/null
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
-sudo $BMV2_PATH/targets/simple_switch/simple_switch resubmit.json \
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH resubmit.json \
     -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
     --nanolog ipc:///tmp/bm-0-log.ipc --log-console \
     --pcap &

examples/simple_nat/run_demo.sh

@@ -21,7 +21,7 @@ fi
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -46,8 +46,10 @@ sysctl net.ipv6.conf.$intf0.disable_ipv6=1
 sysctl net.ipv6.conf.$intf1.disable_ipv6=1
 
 $P4C_BM_SCRIPT p4src/simple_nat.p4 --json simple_nat.json
+# This gives libtool the opportunity to "warm-up"
+$SWITCH_PATH >/dev/null 2>&1
 PYTHONPATH=$PYTHONPATH:$BMV2_PATH/mininet/ python topo.py \
-    --behavioral-exe $BMV2_PATH/targets/simple_switch/simple_switch \
+    --behavioral-exe $SWITCH_PATH \
     --json simple_nat.json \
     --cli $CLI_PATH \
     --thrift-port 22222

examples/simple_nat/sswitch_CLI.sh

@@ -2,7 +2,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 CLI_PATH=$BMV2_PATH/targets/simple_switch/sswitch_CLI
 

workshop_05_2016/ecmp/.starter_code/commands.txt

@@ -0,0 +1,6 @@
+table_set_default send_frame _drop
+table_set_default forward _drop
+table_set_default ipv4_lpm _drop
+table_add send_frame rewrite_mac 1 => 00:aa:bb:00:00:00
+table_add forward set_dmac 10.0.1.1 => 00:04:00:00:00:00
+table_add ipv4_lpm set_nhop 10.0.0.1/32 => 10.0.1.1 1

workshop_05_2016/ecmp/.starter_code/p4src/simple_router.p4

@@ -0,0 +1,190 @@
+/* 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 ipv4_t {
+    fields {
+        version : 4;
+        ihl : 4;
+        diffserv : 8;
+        totalLen : 16;
+        identification : 16;
+        flags : 3;
+        fragOffset : 13;
+        ttl : 8;
+        protocol : 8;
+        hdrChecksum : 16;
+        srcAddr : 32;
+        dstAddr: 32;
+    }
+}
+
+header_type tcp_t {
+    fields {
+        srcPort : 16;
+        dstPort : 16;
+        seqNo : 32;
+        ackNo : 32;
+        dataOffset : 4;
+        res : 3;
+        ecn : 3;
+        ctrl : 6;
+        window : 16;
+        checksum : 16;
+        urgentPtr : 16;
+    }
+}
+
+parser start {
+    return parse_ethernet;
+}
+
+#define ETHERTYPE_IPV4 0x0800
+
+header ethernet_t ethernet;
+
+parser parse_ethernet {
+    extract(ethernet);
+    return select(latest.etherType) {
+        ETHERTYPE_IPV4 : parse_ipv4;
+        default: ingress;
+    }
+}
+
+header ipv4_t ipv4;
+
+field_list ipv4_checksum_list {
+        ipv4.version;
+        ipv4.ihl;
+        ipv4.diffserv;
+        ipv4.totalLen;
+        ipv4.identification;
+        ipv4.flags;
+        ipv4.fragOffset;
+        ipv4.ttl;
+        ipv4.protocol;
+        ipv4.srcAddr;
+        ipv4.dstAddr;
+}
+
+field_list_calculation ipv4_checksum {
+    input {
+        ipv4_checksum_list;
+    }
+    algorithm : csum16;
+    output_width : 16;
+}
+
+calculated_field ipv4.hdrChecksum  {
+    verify ipv4_checksum;
+    update ipv4_checksum;
+}
+
+#define IP_PROTOCOLS_TCP 6
+
+parser parse_ipv4 {
+    extract(ipv4);
+    return select(latest.protocol) {
+        IP_PROTOCOLS_TCP : parse_tcp;
+        default: ingress;
+    }
+}
+
+header tcp_t tcp;
+
+parser parse_tcp {
+    extract(tcp);
+    return ingress;
+}
+
+
+action _drop() {
+    drop();
+}
+
+header_type routing_metadata_t {
+    fields {
+        nhop_ipv4 : 32;
+        // TODO: if you need extra metadata for ECMP, define it here
+    }
+}
+
+metadata routing_metadata_t routing_metadata;
+
+action set_nhop(nhop_ipv4, port) {
+    modify_field(routing_metadata.nhop_ipv4, nhop_ipv4);
+    modify_field(standard_metadata.egress_spec, port);
+    add_to_field(ipv4.ttl, -1);
+}
+
+table ipv4_lpm {
+    reads {
+        ipv4.dstAddr : lpm;
+    }
+    actions {
+        set_nhop;
+        _drop;
+    }
+    size: 1024;
+}
+
+action set_dmac(dmac) {
+    modify_field(ethernet.dstAddr, dmac);
+}
+
+table forward {
+    reads {
+        routing_metadata.nhop_ipv4 : exact;
+    }
+    actions {
+        set_dmac;
+        _drop;
+    }
+    size: 512;
+}
+
+action rewrite_mac(smac) {
+    modify_field(ethernet.srcAddr, smac);
+}
+
+table send_frame {
+    reads {
+        standard_metadata.egress_port: exact;
+    }
+    actions {
+        rewrite_mac;
+        _drop;
+    }
+    size: 256;
+}
+
+control ingress {
+    if(valid(ipv4) and ipv4.ttl > 0) {
+        // TODO: implement ECMP here
+        apply(ipv4_lpm);
+        apply(forward);
+    }
+}
+
+control egress {
+    apply(send_frame);
+}

workshop_05_2016/ecmp/README.md

@@ -0,0 +1,98 @@
+# Implementing ECMP on top of simple_router.p4
+
+## Introduction
+
+simple_router.p4 is a very simple P4 program which does L3 routing. All the P4
+code can be found in the [p4src/simple_router.p4] (p4src/simple_router.p4)
+file. In this exercise we will try to build ECMP on top of the starter code. We
+will be assuming the following network topology:
+
+```
+             --------------------------------- nhop-0 10.0.1.1
+             |                                        00:04:00:00:00:00
+          1 - 00:aa:bb:00:00:00
+             |
+-------- 3--sw
+             |
+          2 - 00:aa:bb:00:00:01
+             |
+             --------------------------------- nhop-1 10.0.2.1
+                                                      00:04:00:00:00:01
+```
+
+Note that we do not assign IPv4 addresses to the 3 switch interfaces, we do not
+need to for this exercise.
+We will be sending test packets on interface `3` of the switch. These packets
+will have destination IP `10.0.0.1`. We will assume that both `nhop-0` and
+`nhop-1` have a path to `10.0.0.1`, which is the final destination of our test
+packets.
+
+## Running the starter code
+
+*Before starting make sure that you run `sudo ./veth_setup.sh` to create the
+veth pairs required for the demo.*
+
+To compile and run the starter code, simply use `./run_demo.sh`. The
+[run_demo.sh] (run_demo.sh) script will run the P4 compiler (for bmv2), start
+the switch and populate the tables using the CLI commands from [commands.txt]
+(commands.txt).
+
+When the switch is running, you can send test packets with `sudo
+./run_test.py`. Note that this script will take a few seconds to complete. The
+test sends a few hundred identical TCP packets through the switch, in bursts,
+on port 3. If you take a look at the P4 code and at commands.txt, you will see
+that each TCP packet is forwarded out of port 1; since we do not have ECMP
+working yet.
+
+## What you need to do
+
+1. In this exercise, you need to update the provided [P4 program]
+(p4src/simple_router.p4) to perform ECMP. When you are done, each incoming TCP
+test packet should be forwarded to either port 1 or port 2, based on the result
+of a crc16 hash computation performed on the TCP 5-tuple (`ipv4.srcAddr`,
+`ipv4.dstAddr`, `ipv4.protocol`, `tcp.srcPort`, `tcp.dstPort`). You will need to
+refer to the [P4 spec] (http://p4.org/wp-content/uploads/2015/04/p4-latest.pdf)
+to familiarize yourself with the P4 constructs you will need.
+
+2. Once you are done with the P4 code, you will need to update [commands.txt]
+(commands.txt) to configure your new tables.
+
+3. After that you can run the above test again. Once again, you will observe
+that all packets go to the same egress port. Don't panic :)! This is because all
+packets are identical and therefore are forwarded in the same way, If you add
+`--random-dport` when running `sudo ./run_test.py`, you should observe an even
+distribution for the ports. This option assigns a random destination port to
+each test TCP packet (the 5-tuple is different, so the hash is likely to be
+different).
+
+## Hints and directions
+
+1. You can easily check the syntax of your P4 program with `p4-validate <path to
+simple_router.p4>`.
+
+2. There are 2 major ways of implementing ECMP on top of simple_router.p4. The
+first one requires 2 tables and the use of the
+`modify_field_with_hash_based_offset` primitive. The second one uses a single
+table with an action profile. You can read about
+`modify_field_with_hash_based_offset` and action profiles in the [P4 spec]
+(http://p4.org/wp-content/uploads/2015/04/p4-latest.pdf).
+
+3. If you choose to use the first way (with 2 tables), your first table will
+match on the destination IP address and be in charge of computing an index
+(using `modify_field_with_hash_based_offset`), while the second table will match
+on this computed index to obtain the outgoing interface. This is a high level
+view of what needs to be implemented in P4.
+```
+T1
+IP_prefix_1 ---> "random" index in [0, 1] using modify_field_with_hash_based_offset
+IP_prefix_2 ---> "random" index in [2, 4] ...
+...
+
+T2
+index(0)    ---> nhop A
+index(1)    ---> nhop B
+index(2)    ---> nhop C
+index(3)    ---> nhop D
+index(4)    ---> nhop E
+```
+Remember that `T1` and `T2`'s entries will come from your modified commands.txt.

workshop_05_2016/ecmp/commands.txt

@@ -0,0 +1,6 @@
+table_set_default send_frame _drop
+table_set_default forward _drop
+table_set_default ipv4_lpm _drop
+table_add send_frame rewrite_mac 1 => 00:aa:bb:00:00:00
+table_add forward set_dmac 10.0.1.1 => 00:04:00:00:00:00
+table_add ipv4_lpm set_nhop 10.0.0.1/32 => 10.0.1.1 1

workshop_05_2016/ecmp/p4src/simple_router.p4

@@ -0,0 +1,190 @@
+/* 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 ipv4_t {
+    fields {
+        version : 4;
+        ihl : 4;
+        diffserv : 8;
+        totalLen : 16;
+        identification : 16;
+        flags : 3;
+        fragOffset : 13;
+        ttl : 8;
+        protocol : 8;
+        hdrChecksum : 16;
+        srcAddr : 32;
+        dstAddr: 32;
+    }
+}
+
+header_type tcp_t {
+    fields {
+        srcPort : 16;
+        dstPort : 16;
+        seqNo : 32;
+        ackNo : 32;
+        dataOffset : 4;
+        res : 3;
+        ecn : 3;
+        ctrl : 6;
+        window : 16;
+        checksum : 16;
+        urgentPtr : 16;
+    }
+}
+
+parser start {
+    return parse_ethernet;
+}
+
+#define ETHERTYPE_IPV4 0x0800
+
+header ethernet_t ethernet;
+
+parser parse_ethernet {
+    extract(ethernet);
+    return select(latest.etherType) {
+        ETHERTYPE_IPV4 : parse_ipv4;
+        default: ingress;
+    }
+}
+
+header ipv4_t ipv4;
+
+field_list ipv4_checksum_list {
+        ipv4.version;
+        ipv4.ihl;
+        ipv4.diffserv;
+        ipv4.totalLen;
+        ipv4.identification;
+        ipv4.flags;
+        ipv4.fragOffset;
+        ipv4.ttl;
+        ipv4.protocol;
+        ipv4.srcAddr;
+        ipv4.dstAddr;
+}
+
+field_list_calculation ipv4_checksum {
+    input {
+        ipv4_checksum_list;
+    }
+    algorithm : csum16;
+    output_width : 16;
+}
+
+calculated_field ipv4.hdrChecksum  {
+    verify ipv4_checksum;
+    update ipv4_checksum;
+}
+
+#define IP_PROTOCOLS_TCP 6
+
+parser parse_ipv4 {
+    extract(ipv4);
+    return select(latest.protocol) {
+        IP_PROTOCOLS_TCP : parse_tcp;
+        default: ingress;
+    }
+}
+
+header tcp_t tcp;
+
+parser parse_tcp {
+    extract(tcp);
+    return ingress;
+}
+
+
+action _drop() {
+    drop();
+}
+
+header_type routing_metadata_t {
+    fields {
+        nhop_ipv4 : 32;
+        // TODO: if you need extra metadata for ECMP, define it here
+    }
+}
+
+metadata routing_metadata_t routing_metadata;
+
+action set_nhop(nhop_ipv4, port) {
+    modify_field(routing_metadata.nhop_ipv4, nhop_ipv4);
+    modify_field(standard_metadata.egress_spec, port);
+    add_to_field(ipv4.ttl, -1);
+}
+
+table ipv4_lpm {
+    reads {
+        ipv4.dstAddr : lpm;
+    }
+    actions {
+        set_nhop;
+        _drop;
+    }
+    size: 1024;
+}
+
+action set_dmac(dmac) {
+    modify_field(ethernet.dstAddr, dmac);
+}
+
+table forward {
+    reads {
+        routing_metadata.nhop_ipv4 : exact;
+    }
+    actions {
+        set_dmac;
+        _drop;
+    }
+    size: 512;
+}
+
+action rewrite_mac(smac) {
+    modify_field(ethernet.srcAddr, smac);
+}
+
+table send_frame {
+    reads {
+        standard_metadata.egress_port: exact;
+    }
+    actions {
+        rewrite_mac;
+        _drop;
+    }
+    size: 256;
+}
+
+control ingress {
+    if(valid(ipv4) and ipv4.ttl > 0) {
+        // TODO: implement ECMP here
+        apply(ipv4_lpm);
+        apply(forward);
+    }
+}
+
+control egress {
+    apply(send_frame);
+}

workshop_05_2016/ecmp/run_demo.sh

@@ -0,0 +1,49 @@
+#!/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/tools/runtime_CLI.py
+
+# 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/simple_router.p4 --json simple_router.json
+if [ $? -ne 0 ]; then
+echo "p4 compilation failed"
+exit 1
+fi
+# This gets root permissions, and gives libtool the opportunity to "warm-up"
+sudo $SWITCH_PATH >/dev/null 2>&1
+sudo $SWITCH_PATH simple_router.json \
+    -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
+    --log-console \
+    --pcap &
+sleep 2
+echo "**************************************"
+echo "Sending commands to switch through CLI"
+echo "**************************************"
+$CLI_PATH --json simple_router.json < commands.txt
+echo "READY!!!"
+fg

workshop_05_2016/ecmp/run_test.py

@@ -0,0 +1,147 @@
+#!/usr/bin/env 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.
+
+import time
+
+NUM_PACKETS = 500
+
+import random
+import argparse
+
+import threading
+from scapy.all import sniff
+from scapy.all import Ether, IP, IPv6, TCP
+
+parser = argparse.ArgumentParser(description='run_test.py')
+parser.add_argument('--random-dport',
+                    help='Use a random TCP dest port for each packet',
+                    action="store_true", default=False)
+args = parser.parse_args()
+
+class PacketQueue:
+    def __init__(self):
+        self.pkts = []
+        self.lock = threading.Lock()
+        self.ifaces = set()
+
+    def add_iface(self, iface):
+        self.ifaces.add(iface)
+
+    def get(self):
+        self.lock.acquire()
+        if not self.pkts:
+            self.lock.release()
+            return None, None
+        pkt = self.pkts.pop(0)
+        self.lock.release()
+        return pkt
+
+    def add(self, iface, pkt):
+        if iface not in self.ifaces:
+            return
+        self.lock.acquire()
+        self.pkts.append( (iface, pkt) )
+        self.lock.release()
+
+queue = PacketQueue()
+
+def pkt_handler(pkt, iface):
+    if IPv6 in pkt:
+        return
+    queue.add(iface, pkt)
+
+class SnifferThread(threading.Thread):
+    def __init__(self, iface, handler = pkt_handler):
+        threading.Thread.__init__(self)
+        self.iface = iface
+        self.handler = handler
+
+    def run(self):
+        sniff(
+            iface = self.iface,
+            prn = lambda x: self.handler(x, self.iface)
+        )
+
+class PacketDelay:
+    def __init__(self, bsize, bdelay, imin, imax, num_pkts = 100):
+        self.bsize = bsize
+        self.bdelay = bdelay
+        self.imin = imin
+        self.imax = imax
+        self.num_pkts = num_pkts
+        self.current = 1
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        if self.num_pkts <= 0:
+            raise StopIteration
+        self.num_pkts -= 1
+        if self.current == self.bsize:
+            self.current = 1
+            return random.randint(self.imin, self.imax)
+        else:
+            self.current += 1
+            return self.bdelay
+
+
+pkt = Ether()/IP(dst='10.0.0.1', ttl=64)/TCP()
+
+port_map = {
+    1: "veth3",
+    2: "veth5",
+    3: "veth7"
+}
+
+iface_map = {}
+for p, i in port_map.items():
+    iface_map[i] = p
+
+queue.add_iface("veth3")
+queue.add_iface("veth5")
+
+for p, iface in port_map.items():
+    t = SnifferThread(iface)
+    t.daemon = True
+    t.start()
+
+import socket
+
+send_socket = socket.socket(socket.AF_PACKET, socket.SOCK_RAW,
+                            socket.htons(0x03))
+send_socket.bind((port_map[3], 0))
+
+delays = PacketDelay(10, 5, 25, 100, NUM_PACKETS)
+ports = []
+print "Sending", NUM_PACKETS, "packets ..."
+for d in delays:
+    # sendp is too slow...
+    # sendp(pkt, iface=port_map[3], verbose=0)
+    if args.random_dport:
+        pkt["TCP"].dport = random.randint(1025, 65535)
+    send_socket.send(str(pkt))
+    time.sleep(d / 1000.)
+time.sleep(1)
+iface, pkt = queue.get()
+while pkt:
+    ports.append(iface_map[iface])
+    iface, pkt = queue.get()
+print ports
+print "DISTRIBUTION..."
+for p in port_map:
+    c = ports.count(p)
+    print "port {}: {:>3} [ {:>5}% ]".format(p, c, 100. * c / NUM_PACKETS)

workshop_05_2016/ecmp/veth_setup.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+noOfVeths=18
+if [ $# -eq 1 ]; then 
+    noOfVeths=$1
+fi
+echo "No of Veths is $noOfVeths"
+idx=0
+let "vethpairs=$noOfVeths/2"
+while [ $idx -lt $vethpairs ]
+do 
+    intf0="veth$(($idx*2))"
+    intf1="veth$(($idx*2+1))"
+    idx=$((idx + 1))
+    if ! ip link show $intf0 &> /dev/null; then
+        ip link add name $intf0 type veth peer name $intf1
+        ip link set dev $intf0 up
+        ip link set dev $intf1 up
+        TOE_OPTIONS="rx tx sg tso ufo gso gro lro rxvlan txvlan rxhash"
+        for TOE_OPTION in $TOE_OPTIONS; do
+           /sbin/ethtool --offload $intf0 "$TOE_OPTION" off
+           /sbin/ethtool --offload $intf1 "$TOE_OPTION" off
+        done
+    fi
+    sysctl net.ipv6.conf.$intf0.disable_ipv6=1
+    sysctl net.ipv6.conf.$intf1.disable_ipv6=1
+done