ft_traceroute

Recoding the traceroute command to deepen the knowledge of the network (TCP/IP) by following the paths that an IP packet will take between two machines.

$> man traceroute

traceroute tracks the route packets taken from an IP network on their way to a given host. It utilizes the IP protocol's time to live (TTL) field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to the host.

Basic implementation

• Sending UDP in loop while increasing TTL

• Send max_hops packets for each TTL size

• If a packet is not acknowledged within the expected interval, * is displayed

• The destination port number will be incremented by each probe

Features

• parameters
  • takes IPv4 (address/hostname) as a program parameter
• options
  • --help
• hostname resolution
  • manage the FQDN without running the DNS resolution in the jump display

bonus

option	parameter	details
-f, --first	1 - max_hops	Start from the first_ttl hop (instead from 1)
-m, --max-hops	1 - 255 (error)	Specifies the maximum number of hops (max time-to-live value) traceroute will probe. (default: 64)
-p, --port	1 - 65535 (loop)	Specifies the destination port base traceroute will use (default: 33434)
-q, --queries	1 - 10 (error)	Sets the number of probe packets per hop. (default: 3)
-w, --wait	0 - 60 (int)	wait NUM seconds for response (default: 3)

Improvements

• display current ttl instead of current hop
• display error msg when first-ttl is greater than max-hops

Implementations

• create socket
• loop num_max_hop time
  • loop num_tries time
    • send packet
    • set timeout to select()
      • wait response for max num_wait seconds
    • print result ( ip & triptime / "*" )
  • QUIT: if src is dst