gogoping

README

GoGoPing

A rewrite of the ping application from C to go. Create a tool that is useful in debugging connections to the Internet.

But Why Though?

1. Because I can
2. I thought it would be fun
3. Learning

Requirements

• Take a hostname or ipaddress as input
  • Do a DNS Lookup
• Opens a socket
• When Ctl+c is pressed to exit, present the user with a report of aggregated statistics
• Support command line arguments and flags
  • ping 127.0.0.1 -f -l 1400 -Fails
  • -l
  • -t
  • -f

Rules

1. Limit resources to the following go lang spec, wikipedia, networking RFCs, effective go, the go std library
2. Attempt to make use of concurrency
3. Half attempt writing a real app, and not a single giant spaghetti code mess

Resources

• (Miro Board)[https://miro.com/app/board/uXjVPd_Mth8=/]

TIL

Struct fields exported or unexported

• Go's visibility flag are denoted by lowercase and capitalize letters
  • They're as Exported and unexported
• https://pkg.go.dev/golang.org/x/net/icmp exists
  • probably don't want to entirely reinvent this wheel

package main
type animal struct {
	Cute bool
	food bool
	legs int
}

animal.Cute would be accessible to other packages animal.legs & animal.food would not be accessible to other packages.

defer statements

Defer functions are executed in LIFO (last in first out) order.

I'm using them as a way to ensure that claimed resources are restored once we're done with them.

Apple to the eye

Apple ships with a different version of ping. Because why should I expect anything else.

https://opensource.apple.com/source/network_cmds/network_cmds-511/ping.tproj/

Bitwise OR operator

| bitwise or operator.

Copies any bits from either side of the equation

var a,b,c uint8
a = 60      // 0011 1100
b = 13      // 0000 1101
c = 60 | 13 // 0011 11011

Sockets

Documentation

Come from BSD and the API specifications are contained in an IEEE publication. Berkley Sockets, BSD Sockets, and POSIX Sockets are all synonyms for the same thing.