Using the protocolentry class

- Introduction
- Lookup By Name
- Lookup By Number

### Introduction

The protocolentry class provides methods for retrieving network protocol definitions. These are usually defined in a file like /etc/protocols on unix-like systems or C:\Windows\System32\drivers\etc\protocol on Windows, or are served from another source via the name-service switch.

Protocols can be looked up by name or number.

### Lookup By Name

This example retrieves network protocol information for the "tcp" protocol.

> #include <rudiments/protocolentry.h>
> #include <rudiments/stdio.h>
> int main(int argc, const char **argv) {
> // get the protocol entry for the "tcp" protocol
> protocolentry pe;
> pe.initialize("tcp");
> // print out details
> stdoutput.printf(" Name: %s\n",pe.getName());
> stdoutput.printf(" Alias list:\n");
> for (uint32_t i=0; pe.getAliasList() && pe.getAliasList()[i]; i++) {
> stdoutput.printf(" %s\n",pe.getAliasList()[i]);
> }
> stdoutput.printf(" Number: %d\n",pe.getNumber());
> stdoutput.printf("\n");
> }

### Lookup By Number

This example retrieves network protocol information for "protocol number 6".

> #include <rudiments/protocolentry.h>
> #include <rudiments/stdio.h>
> int main(int argc, const char **argv) {
> // get the protocol entry for "protocol number 6"
> protocolentry pe;
> pe.initialize(6);
> // print out details
> stdoutput.printf(" Name: %s\n",pe.getName());
> stdoutput.printf(" Alias list:\n");
> for (uint32_t i=0; pe.getAliasList() && pe.getAliasList()[i]; i++) {
> stdoutput.printf(" %s\n",pe.getAliasList()[i]);
> }
> stdoutput.printf(" Number: %d\n",pe.getNumber());
> stdoutput.printf("\n");
> }