# 網路模擬與分析(5/17): P4
###### tags: `Mininet`、`P4`
---
**--------------目前為純 code 及 result，詳解部分之後更新--------------**
---
## MAC Layer Forwarding
`p4app.json`:
```
{
"program": "basic.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy": "l2",
"links": [["h1", "s1"], ["h2", "s1"]],
"hosts": {
"h1": {
},
"h2": {
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "basic.p4"
}
}
}
}
```
`basic.p4`:
```
/* -*- P4_16 -*- */
#include <core.p4>
#include <v1model.p4>
/*************************************************************************
*********************** H E A D E R S ***********************************
*************************************************************************/
header ethernet_t {
bit<48> dstAddr;
bit<48> srcAddr;
bit<16> etherType;
}
struct metadata {
/* empty */
}
struct headers {
ethernet_t ethernet;
}
/*************************************************************************
*********************** P A R S E R ***********************************
*************************************************************************/
parser MyParser(packet_in packet,
out headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
state start {
transition parse_ethernet;
}
state parse_ethernet {
packet.extract(hdr.ethernet);
transition accept;
}
}
/*************************************************************************
************ C H E C K S U M V E R I F I C A T I O N *************
*************************************************************************/
control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
apply { }
}
/*************************************************************************
************** I N G R E S S P R O C E S S I N G *******************
*************************************************************************/
control MyIngress(inout headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
action drop() {
mark_to_drop(standard_metadata);
}
action forward(bit<9> port) {
standard_metadata.egress_spec = port;
}
table mac_forward {
key = {
hdr.ethernet.dstAddr: exact;
}
actions = {
forward;
drop;
}
size = 1024;
default_action = drop();
}
apply {
mac_forward.apply();
}
}
/*************************************************************************
**************** E G R E S S P R O C E S S I N G *******************
*************************************************************************/
control MyEgress(inout headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
apply { }
}
/*************************************************************************
************* C H E C K S U M C O M P U T A T I O N **************
*************************************************************************/
control MyComputeChecksum(inout headers hdr, inout metadata meta) {
apply {
}
}
/*************************************************************************
*********************** D E P A R S E R *******************************
*************************************************************************/
control MyDeparser(packet_out packet, in headers hdr) {
apply {
packet.emit(hdr.ethernet);
}
}
/*************************************************************************
*********************** S W I T C H *******************************
*************************************************************************/
V1Switch(
MyParser(),
MyVerifyChecksum(),
MyIngress(),
MyEgress(),
MyComputeChecksum(),
MyDeparser()
) main;
```
`cmd.txt`:
```
table_add mac_forward forward 00:00:0a:00:01:01 => 1
table_add mac_forward forward 00:00:0a:00:01:02 => 2
```
`p4run`
---
### MAC Layer Forwarding (HomeWork-1)
`p4app.json`:
```
{
"program": "basic.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy":"l2",
"links": [["h1", "s1"], ["h2", "s2"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
"hosts": {
"h1": {
},
"h2": {
},
"h3": {
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "basic.p4"
},
"s2": {
"cli_input": "cmd2.txt",
"program": "basic.p4"
},
"s3": {
"cli_input": "cmd3.txt",
"program": "basic.p4"
}
}
}
}
```
`basic.p4`
```
/* -*- P4_16 -*- */
#include <core.p4>
#include <v1model.p4>
/*************************************************************************
*********************** H E A D E R S ***********************************
*************************************************************************/
header ethernet_t {
bit<48> dstAddr;
bit<48> srcAddr;
bit<16> etherType;
}
struct metadata {
/* empty */
}
struct headers {
ethernet_t ethernet;
}
/*************************************************************************
*********************** P A R S E R ***********************************
*************************************************************************/
parser MyParser(packet_in packet,
out headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
state start {
transition parse_ethernet;
}
state parse_ethernet {
packet.extract(hdr.ethernet);
transition accept;
}
}
/*************************************************************************
************ C H E C K S U M V E R I F I C A T I O N *************
*************************************************************************/
control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
apply { }
}
/*************************************************************************
************** I N G R E S S P R O C E S S I N G *******************
*************************************************************************/
control MyIngress(inout headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
action drop() {
mark_to_drop(standard_metadata);
}
action forward(bit<9> port) {
standard_metadata.egress_spec = port;
}
table mac_forward {
key = {
hdr.ethernet.dstAddr: exact;
}
actions = {
forward;
drop;
}
size = 1024;
default_action = drop();
}
apply {
mac_forward.apply();
}
}
/*************************************************************************
**************** E G R E S S P R O C E S S I N G *******************
*************************************************************************/
control MyEgress(inout headers hdr,
inout metadata meta,
inout standard_metadata_t standard_metadata) {
apply { }
}
/*************************************************************************
************* C H E C K S U M C O M P U T A T I O N **************
*************************************************************************/
control MyComputeChecksum(inout headers hdr, inout metadata meta) {
apply {
}
}
/*************************************************************************
*********************** D E P A R S E R *******************************
*************************************************************************/
control MyDeparser(packet_out packet, in headers hdr) {
apply {
packet.emit(hdr.ethernet);
}
}
/*************************************************************************
*********************** S W I T C H *******************************
*************************************************************************/
V1Switch(
MyParser(),
MyVerifyChecksum(),
MyIngress(),
MyEgress(),
MyComputeChecksum(),
MyDeparser()
) main;
```
`cmd.txt`:
```
table_add mac_forward forward 00:00:0a:00:00:01 => 1
table_add mac_forward forward 00:00:0a:00:00:02 => 2
table_add mac_forward forward 00:00:0a:00:00:03 => 2
```
`cmd2.txt`:
```
table_add mac_forward forward 00:00:0a:00:00:01 => 2
table_add mac_forward forward 00:00:0a:00:00:02 => 1
table_add mac_forward forward 00:00:0a:00:00:03 => 3
```
`cmd3.txt`:
```
table_add mac_forward forward 00:00:0a:00:00:01 => 2
table_add mac_forward forward 00:00:0a:00:00:02 => 2
table_add mac_forward forward 00:00:0a:00:00:03 => 1
```
`p4run`
---
## Network Layer Forwarding
`p4app.json`:
```
{
"program": "ip_forward.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy": "manual",
"auto_arp_tables": "true",
"auto_gw_arp": "true",
"links": [["h1", "s1"], ["h2", "s1"]],
"hosts": {
"h1": {
"ip": "10.0.1.1/24",
"gw": "10.0.1.254"
},
"h2": {
"ip": "10.0.2.1/24",
"gw": "10.0.2.254"
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "ip_forward.p4"
}
}
}
}
```
`ip_forwarding.p4`:
```
#include <core.p4>
#include <v1model.p4>
typedef bit<48> macAddr_t;
typedef bit<9> egressSpec_t;
header arp_t {
bit<16> htype;
bit<16> ptype;
bit<8> hlen;
bit<8> plen;
bit<16> opcode;
bit<48> hwSrcAddr;
bit<32> protoSrcAddr;
bit<48> hwDstAddr;
bit<32> protoDstAddr;
}
header ethernet_t {
bit<48> dstAddr;
bit<48> srcAddr;
bit<16> etherType;
}
header ipv4_t {
bit<4> version;
bit<4> ihl;
bit<8> diffserv;
bit<16> totalLen;
bit<16> identification;
bit<3> flags;
bit<13> fragOffset;
bit<8> ttl;
bit<8> protocol;
bit<16> hdrChecksum;
bit<32> srcAddr;
bit<32> dstAddr;
}
struct metadata {
}
struct headers {
@name(".arp")
arp_t arp;
@name(".ethernet")
ethernet_t ethernet;
@name(".ipv4")
ipv4_t ipv4;
}
parser ParserImpl(packet_in packet, out headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
@name(".parse_arp") state parse_arp {
packet.extract(hdr.arp);
transition accept;
}
@name(".parse_ethernet") state parse_ethernet {
packet.extract(hdr.ethernet);
transition select(hdr.ethernet.etherType) {
16w0x800: parse_ipv4;
16w0x806: parse_arp;
default: accept;
}
}
@name(".parse_ipv4") state parse_ipv4 {
packet.extract(hdr.ipv4);
transition accept;
}
@name(".start") state start {
transition parse_ethernet;
}
}
control egress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
apply {
}
}
control ingress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
@name(".set_nhop") action set_nhop(macAddr_t dstAddr, egressSpec_t port) {
//set the src mac address as the previous dst, this is not correct right?
hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
//set the destination mac address that we got from the match in the table
hdr.ethernet.dstAddr = dstAddr;
//set the output port that we also get from the table
standard_metadata.egress_spec = port;
//decrease ttl by 1
hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
}
@name("._drop") action _drop() {
mark_to_drop(standard_metadata);
}
@name(".ipv4_lpm") table ipv4_lpm {
actions = {
set_nhop;
_drop;
}
key = {
hdr.ipv4.dstAddr: lpm;
}
size = 512;
const default_action = _drop();
}
apply {
ipv4_lpm.apply();
}
}
control DeparserImpl(packet_out packet, in headers hdr) {
apply {
packet.emit(hdr.ethernet);
packet.emit(hdr.arp);
packet.emit(hdr.ipv4);
}
}
control verifyChecksum(inout headers hdr, inout metadata meta) {
apply {
verify_checksum(true, { hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr }, hdr.ipv4.hdrChecksum, HashAlgorithm.csum16);
}
}
control computeChecksum(inout headers hdr, inout metadata meta) {
apply {
update_checksum(true, { hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr }, hdr.ipv4.hdrChecksum, HashAlgorithm.csum16);
}
}
V1Switch(ParserImpl(), verifyChecksum(), ingress(), egress(), computeChecksum(), DeparserImpl()) main;
```
`cmd.txt`:
```
table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.2.1/32 => 00:00:0a:00:02:01 2
```
`p4run`
### Network Layer Forwarding (homework 2)
`p4app.json`:
```
{
"program": "ip_forward.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy": "l3",
"auto_arp_tables": "true",
"auto_gw_arp": "true",
"links": [["h1", "s1"], ["h2", "s2"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
"hosts": {
"h1": {
"ip": "10.1.1.2/24",
"gw": "10.1.1.254"
},
"h2": {
"ip": "10.2.2.2/24",
"gw": "10.2.2.254"
},
"h3": {
"ip": "10.3.3.2/24",
"gw": "10.3.3.254"
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "ip_forward.p4"
},
"s2": {
"cli_input": "cmd2.txt",
"program": "ip_forward.p4"
},
"s3": {
"cli_input": "cmd3.txt",
"program": "ip_forward.p4"
}
}
}
}
```
`ip_forward.p4`
```
#include <core.p4>
#include <v1model.p4>
typedef bit<48> macAddr_t;
typedef bit<9> egressSpec_t;
header arp_t {
bit<16> htype;
bit<16> ptype;
bit<8> hlen;
bit<8> plen;
bit<16> opcode;
bit<48> hwSrcAddr;
bit<32> protoSrcAddr;
bit<48> hwDstAddr;
bit<32> protoDstAddr;
}
header ethernet_t {
bit<48> dstAddr;
bit<48> srcAddr;
bit<16> etherType;
}
header ipv4_t {
bit<4> version;
bit<4> ihl;
bit<8> diffserv;
bit<16> totalLen;
bit<16> identification;
bit<3> flags;
bit<13> fragOffset;
bit<8> ttl;
bit<8> protocol;
bit<16> hdrChecksum;
bit<32> srcAddr;
bit<32> dstAddr;
}
struct metadata {
}
struct headers {
@name(".arp")
arp_t arp;
@name(".ethernet")
ethernet_t ethernet;
@name(".ipv4")
ipv4_t ipv4;
}
parser ParserImpl(packet_in packet, out headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
@name(".parse_arp") state parse_arp {
packet.extract(hdr.arp);
transition accept;
}
@name(".parse_ethernet") state parse_ethernet {
packet.extract(hdr.ethernet);
transition select(hdr.ethernet.etherType) {
16w0x800: parse_ipv4;
16w0x806: parse_arp;
default: accept;
}
}
@name(".parse_ipv4") state parse_ipv4 {
packet.extract(hdr.ipv4);
transition accept;
}
@name(".start") state start {
transition parse_ethernet;
}
}
control egress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
apply {
}
}
control ingress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
@name(".set_nhop") action set_nhop(macAddr_t dstAddr, egressSpec_t port) {
//set the src mac address as the previous dst, this is not correct right?
hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
//set the destination mac address that we got from the match in the table
hdr.ethernet.dstAddr = dstAddr;
//set the output port that we also get from the table
standard_metadata.egress_spec = port;
//decrease ttl by 1
hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
}
@name("._drop") action _drop() {
mark_to_drop(standard_metadata);
}
@name(".ipv4_lpm") table ipv4_lpm {
actions = {
set_nhop;
_drop;
}
key = {
hdr.ipv4.dstAddr: lpm;
}
size = 512;
const default_action = _drop();
}
apply {
ipv4_lpm.apply();
}
}
control DeparserImpl(packet_out packet, in headers hdr) {
apply {
packet.emit(hdr.ethernet);
packet.emit(hdr.arp);
packet.emit(hdr.ipv4);
}
}
control verifyChecksum(inout headers hdr, inout metadata meta) {
apply {
verify_checksum(true, { hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr }, hdr.ipv4.hdrChecksum, HashAlgorithm.csum16);
}
}
control computeChecksum(inout headers hdr, inout metadata meta) {
apply {
update_checksum(true, { hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr }, hdr.ipv4.hdrChecksum, HashAlgorithm.csum16);
}
}
V1Switch(ParserImpl(), verifyChecksum(), ingress(), egress(), computeChecksum(), DeparserImpl()) main;
```
`cmd.txt`:
```
table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 1
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 2
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 2
```
`cmd2.txt`:
```
table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 2
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 1
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 3
```
`cmd3.txt`:
```
table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 2
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 2
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 1
```
`p4run`:
### Network Layer Forwarding (HomeWork-2)
`p4app.json`:
```
{
"program": "ip_forward.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy": "mixed",
"auto_arp_tables": "true",
"auto_gw_arp": "true",
"links": [["h1", "s1"], ["h2", "s3"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
"hosts": {
"h1": {
},
"h2": {
},
"h3": {
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "ip_forward.p4"
},
"s2": {
"cli_input": "cmd2.txt",
"program": "ip_forward.p4"
},
"s3": {
"cli_input": "cmd3.txt",
"program": "ip_forward.p4"
}
}
}
}
```
`ip_forward.p4`
```
{
"program": "ip_forward.p4",
"switch": "simple_switch",
"compiler": "p4c",
"options": "--target bmv2 --arch v1model --std p4-16",
"switch_cli": "simple_switch_CLI",
"cli": true,
"pcap_dump": true,
"enable_log": true,
"topo_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.apptopo",
"object_name": "AppTopoStrategies"
},
"controller_module": null,
"topodb_module": {
"file_path": "",
"module_name": "p4utils.utils.topology",
"object_name": "Topology"
},
"mininet_module": {
"file_path": "",
"module_name": "p4utils.mininetlib.p4net",
"object_name": "P4Mininet"
},
"topology": {
"assignment_strategy": "mixed",
"auto_arp_tables": "true",
"auto_gw_arp": "true",
"links": [["h1", "s1"], ["h2", "s3"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
"hosts": {
"h1": {
},
"h2": {
},
"h3": {
}
},
"switches": {
"s1": {
"cli_input": "cmd.txt",
"program": "ip_forward.p4"
},
"s2": {
"cli_input": "cmd2.txt",
"program": "ip_forward.p4"
},
"s3": {
"cli_input": "cmd3.txt",
"program": "ip_forward.p4"
}
}
}
}
```
`cmd.txt`
```
table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 2
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2
```
`cmd2.txt`
```
table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 2
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2
```
`cmd3.txt`
```
table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 3
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 1
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2
```
`p4run`:
---
## Reference
1. https://www.youtube.com/watch?v=rOODoTlnKtI&feature=emb_title
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