Updated README files for exercises (#82)

* Adding initial implementation of basic_encap example

* Updated basic_encap example to count the number of valid packets

* Updated basic_encap example to put encapsulation layer after Ethernet
header.

* Added solution file for basic_encap example

* Changed the name of the basic_encap example to basic_tunnel and called
the new header myTunnel. Also changed the myTunnel field names slightly.

* Updated the README file for the basic_tunnel exercise. Also added topo.pdf
image to serve as a reference during implementation.

* Updated basic/README.md to point to basic_tunnel as the next exercise.

* Updated the README for basic to point to basic_tunnel.

Updated the starter code for basic_tunnel to look like basic
solution with todo comments.

Updated send.py and receive.py to be able to send both plain IP
packets and tunneled IP packets.

Updated basic_tunnel.p4 to have same control flow as p4runtime
exercise.

* Updated the basic and basic_tunnel README files to remove references
to the old run.sh script.

Updated TODO list in basic_tunnel README

* Updated README files to indicate logs are in /tmp

P4D2_2017_Fall/exercises/basic/README.md

@@ -146,12 +146,12 @@ report the error emitted from the compiler and halt.
 2. `basic.p4` might compile but fail to support the control plane
 rules in the `s1-commands.txt` through `s3-command.txt` files that
 `make run` tries to install using the Bmv2 CLI. In this case, `make run`
-will report these errors to `stderr`. Use these error messages to fix
-your `basic.p4` implementation.
+will log the CLI tool output in the `logs` directory. Use these error 
+messages to fix your `basic.p4` implementation.
 
 3. `basic.p4` might compile, and the control plane rules might be
 installed, but the switch might not process packets in the desired
-way. The `build/logs/<switch-name>.log` files contain detailed logs
+way. The `/tmp/p4s.<switch-name>.log` files contain detailed logs
 that describing how each switch processes each packet. The output is
 detailed and can help pinpoint logic errors in your implementation.
 

P4D2_2017_Fall/exercises/basic_tunnel/README.md

@@ -140,12 +140,12 @@ report the error emitted from the compiler and halt.
 2. `basic_tunnel.p4` might compile but fail to support the control plane
 rules in the `s1-commands.txt` through `s3-command.txt` files that
 `make run` tries to install using the Bmv2 CLI. In this case, `make run`
-will report these errors to `stderr`. Use these error messages to fix
-your `basic_tunnel.p4` implementation or forwarding rules.
+will log the CLI tool output in the `logs` directory. Use these error 
+messages to fix your `basic_tunnel.p4` implementation or forwarding rules.
 
 3. `basic_tunnel.p4` might compile, and the control plane rules might be
 installed, but the switch might not process packets in the desired
-way. The `build/logs/<switch-name>.log` files contain detailed logs
+way. The `/tmp/p4s.<switch-name>.log` files contain detailed logs
 that describing how each switch processes each packet. The output is
 detailed and can help pinpoint logic errors in your implementation.
 

P4D2_2017_Fall/exercises/ecn/README.md

@@ -162,12 +162,12 @@ There are several ways that problems might manifest:
    error emitted from the compiler and stop.
 2. `ecn.p4` compiles but does not support the control plane rules in
    the `sX-commands.txt` files that `make` tries to install using
-   the BMv2 CLI.  In this case, `make` will report these errors to
-   `stderr`.  Use these error messages to fix your `ecn.p4`
+   the BMv2 CLI.  In this case, `make` will log the CLI tool output 
+   in th `logs` directory. Use these error messages to fix your `ecn.p4`
    implementation.
 3. `ecn.p4` compiles, and the control plane rules are installed, but
    the switch does not process packets in the desired way.  The
-   `build/logs/<switch-name>.log` files contain trace messages
+   `/tmp/p4s.<switch-name>.log` files contain trace messages
    describing how each switch processes each packet.  The output is
    detailed and can help pinpoint logic errors in your implementation.
    The `build/<switch-name>-<interface-name>.pcap` also contains the

P4D2_2017_Fall/exercises/load_balance/README.md

@@ -117,13 +117,13 @@ report the error emitted from the compiler and stop.
 
 2. `load_balance.p4` compiles but does not support the control plane
 rules in the `sX-commands.txt` files that `make` tries to install
-using the BMv2 CLI.  In this case, `make` will report these errors
-to `stderr`.  Use these error messages to fix your `load_balance.p4`
+using the BMv2 CLI.  In this case, `make` will log the CLI tool output
+in the `logs` directory. Use these error messages to fix your `load_balance.p4`
 implementation.
 
 3. `load_balance.p4` compiles, and the control plane rules are
 installed, but the switch does not process packets in the desired way.
-The `build/logs/<switch-name>.log` files contain trace messages
+The `/tmp/p4s.<switch-name>.log` files contain trace messages
 describing how each switch processes each packet.  The output is
 detailed and can help pinpoint logic errors in your implementation.
 

P4D2_2017_Fall/exercises/mri/README.md

@@ -211,11 +211,11 @@ There are several ways that problems might manifest:
 error emitted from the compiler and stop.
 2. `mri.p4` compiles but does not support the control plane rules in
 the `sX-commands.txt` files that `make` tries to install using the BMv2 CLI.
-In this case, `make` will report these errors to `stderr`. Use these error
-messages to fix your `mri.p4` implementation.
+In this case, `make` will log the CLI tool output in the `logs` directory.
+Use these error messages to fix your `mri.p4` implementation.
 3. `mri.p4` compiles, and the control plane rules are installed, but
 the switch does not process packets in the desired way. The
-`build/logs/<switch-name>.log` files contain trace messages describing
+`/tmp/p4s.<switch-name>.log` files contain trace messages describing
 how each switch processes each packet. The output is detailed and can
 help pinpoint logic errors in your implementation.  The
 `build/<switch-name>-<interface-name>.pcap` also contains the pcap of

P4D2_2017_Fall/exercises/source_routing/README.md

@@ -123,7 +123,7 @@ There are several ways that problems might manifest:
    Do you have another instance of mininet running? Did the previous
    run of mininet crash?  if yes, check "Cleaning up Mininet" bellow.
 3. `source_routing.p4` compiles but the switch does not process
-   packets in the desired way. The `build/logs/<switch-name>.log`
+   packets in the desired way. The `/tmp/p4s.<switch-name>.log`
    files contain trace messages describing how each switch processes
    each packet. The output is detailed and can help pinpoint logic
    errors in your implementation.  The