The set of functions which routes packets. More...

#include <netinet/in.h>
#include <sys/time.h>
#include <stdio.h>
#include "sr_protocol.h"
#include "sr_arpcache.h"

Include dependency graph for sr_router.h:

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Go to the source code of this file.

Classes
struct	sr_instance
	Struct which encapsulates all the state of a single router. More...

Macros
#define	min(a, b) ( (a) < (b) ? (a) : (b) )

#define	Debug(x, args...) do{}while(0)

#define	DebugMAC(x) do{}while(0)

#define	INIT_TTL 255

#define	PACKET_DUMP_SIZE 1024

#define	ETH_HEADER_LEN 14
	number of uint8_ts in the Ethernet header (dst MAC + src MAC + type)

#define	ETH_MAX_DATA_LEN 2048
	max uint8_ts in the payload (usually 1500B, but jumbo may be larger

#define	ETH_MAX_LEN (ETH_HEADER_LEN + ETH_MAX_DATA_LEN)
	max uint8_ts in the Ethernet frame (header + data uint8_ts)

#define	ETH_MIN_LEN 60
	min uint8_ts in the Ethernet frame

#define	IPV4_HEADER_LEN 20
	number of uint8_ts in an IPv4 header without options. More...

Functions
int	sr_verify_routing_table (struct sr_instance *sr)

int	sr_send_packet (struct sr_instance , uint8_t , unsigned int, const char *)
	Send a packet (ethernet header included!) of length 'len' onto the wire. More...

int	sr_connect_to_server (struct sr_instance , unsigned short, char )

int	sr_read_from_server (struct sr_instance *)

void	sr_init (struct sr_instance *)
	Initializes router state.

void	sr_handlepacket (struct sr_instance , uint8_t , unsigned int, char *)
	Called whenever an incoming packet is received; You are responsible for writing this. More...

int	ether_to_me (unsigned char my_address, unsigned char addr_s)
	Determine if an ethernet frame is addressed to a given interface's MAC address. More...

int	handle_arp (struct sr_instance sr, uint8_t packet, unsigned int len, char *interface)
	Handles all incoming packets with an ARP header; You are responsible for writing this. More...

int	handle_ip (struct sr_instance sr, uint8_t packet, unsigned int len, char *interface)
	Handles all incoming packets with an IP header; You are responsible for writing this. More...

uint16_t	checksum_ip (struct sr_ip_hdr *hdr)
	Helper function which computes and sets the checksum on an IP header.

uint16_t	checksum (uint16_t *buf, unsigned len)
	Helper function which computes the checksum over the specified length of the given buffer.

int	ip_to_me (struct sr_instance *, uint32_t)
	Helper function to determine whether an IP packet is destined for any of the router's interfaces' addresses. More...

void	icmp_send (struct sr_instance router, uint32_t dst, uint32_t src, uint8_t ip_packet, unsigned len, uint8_t type, uint8_t code, uint16_t id, uint16_t seq)
	Creates an ICMP header and encapsulates the given buffer (if any); You are responsible for writing this. More...

uint16_t	checksum_icmp (sr_icmp_hdr_t *icmp_hdr, unsigned total_len)
	Computes and sets the checksum on an ICMP header.

void	icmp_handle_packet (struct sr_instance router, uint8_t ip_packet, unsigned len)
	Handles all incoming packets with an ICMP header; This is already implemented for you.

int	ip_send_packet_from (struct sr_instance , uint32_t dst, uint32_t src, uint8_t proto, uint8_t buf, unsigned len)
	Creates an IP header and encapsulates the given buffer; You are responsible for writing this. More...

int	ip_send_packet (struct sr_instance router, uint32_t dst, uint8_t proto, uint8_t payload, unsigned len)
	Wrapper function for ip_send_packet_from when the outbound address & interface are not known; This is already implemented for you. More...

int	router_send_ethernet_frame (struct sr_instance router, uint32_t dst_ip, uint16_t type, uint8_t payload, unsigned len)
	Searches the routing table to find the correct interface on which to send the payload based on the destination IP, then queues the packet; This is already implemented for you. More...

int	router_queue_ethernet_frame (struct sr_instance router, struct sr_rt rti, struct sr_if intf, uint16_t type, uint8_t payload, unsigned payload_len)
	Constructs an ethernet packet to the correct MAC address - if this exists in the cache the packet can be sent immediately, otherwise it must be queued while the ARP cache resolves the next hop IP address's MAC address; You are responsible for writing this. More...

struct sr_rt *	rtable_find_route (struct sr_instance *sr, uint32_t ip)
	Given a destination IP address, looks up the routing table entry for the next hop; This is already implemented for you.

int	handle_arpreq (struct sr_instance sr, struct sr_arpreq req)
	Handles sending ARP requests to get IP/MAC mappings; You are responsible for writing this. More...

void	sr_add_interface (struct sr_instance , const char )

void	sr_set_ether_ip (struct sr_instance *, uint32_t)

void	sr_set_ether_addr (struct sr_instance , const unsigned char )

void	sr_print_if_list (struct sr_instance *)
	Prints the interface list.

Variables
struct sr_instance	__attribute__

Detailed Description

The set of functions which routes packets.

Macro Definition Documentation

◆ IPV4_HEADER_LEN

#define IPV4_HEADER_LEN 20

number of uint8_ts in an IPv4 header without options.

Function Documentation

◆ ether_to_me()

int ether_to_me	(	unsigned char *	my_address,
		unsigned char *	addr_s
	)

Determine if an ethernet frame is addressed to a given interface's MAC address.

Parameters

my_address	the router interface's MAC address
addr_s	the MAC address we would like to check against

Returns: Nonzero (true) if the addresses match, or the second argument is the broadcast address. Zero (false) otherwise.

◆ handle_arp()

int handle_arp	(	struct sr_instance *	sr,
		uint8_t *	packet,
		unsigned int	len,
		char *	interface
	)

Handles all incoming packets with an ARP header; You are responsible for writing this.

Parameters

sr	the router instance
packet	the raw ARP packet
len	the size of the raw ARP packet
interface	the name of the interface which the packet arrived on

◆ handle_arpreq()

int handle_arpreq	(	struct sr_instance *	sr,
		struct sr_arpreq *	req
	)

Handles sending ARP requests to get IP/MAC mappings; You are responsible for writing this.

Parameters

sr	the router instance
req	the ARP request to be resolved

◆ handle_ip()

int handle_ip	(	struct sr_instance *	sr,
		uint8_t *	packet,
		unsigned int	len,
		char *	interface
	)

Handles all incoming packets with an IP header; You are responsible for writing this.

Parameters

sr	the router instance
packet	the raw IP packet
len	the size of the raw IP packet
interface	the name of the interface which the packet arrived on

◆ icmp_send()

void icmp_send	(	struct sr_instance *	router,
		uint32_t	dst,
		uint32_t	src,
		uint8_t *	ip_packet,
		unsigned	len,
		uint8_t	type,
		uint8_t	code,
		uint16_t	id,
		uint16_t	seq
	)

Creates an ICMP header and encapsulates the given buffer (if any); You are responsible for writing this.

Parameters

router	the router instance
dst	the destination address
src	the source address
ip_packet	the IP packet which triggered the creation of this ICMP packet, if any
len	the length of the IP packet, if any
type	type of ICMP packet to be created
code	code of ICMP packet to be created
id	id of the ICMP packet
seq	sequence number of the ICMP packet

◆ ip_send_packet()

int ip_send_packet	(	struct sr_instance *	router,
		uint32_t	dst,
		uint8_t	proto,
		uint8_t *	payload,
		unsigned	len
	)

Wrapper function for ip_send_packet_from when the outbound address & interface are not known; This is already implemented for you.

Parameters

router	the router instance
dst	the destination address
proto	the protocol of the encapsulated buffer
payload	buffer to encapsulate with IP header
len	size of the buffer

◆ ip_send_packet_from()

int ip_send_packet_from	(	struct sr_instance *	,
		uint32_t	dst,
		uint32_t	src,
		uint8_t	proto,
		uint8_t *	buf,
		unsigned	len
	)

Creates an IP header and encapsulates the given buffer; You are responsible for writing this.

Parameters

sr_instance	the router instance
dst	the destination address
src	the source address
proto	the protocol of the encapsulated buffer
buf	buffer to encapsulate with IP header
len	size of the buffer

◆ ip_to_me()

int ip_to_me	(	struct sr_instance *	,
		uint32_t
	)

Helper function to determine whether an IP packet is destined for any of the router's interfaces' addresses.

Parameters

sr_instance	the router instance
uint32_t	the destination address in question

◆ router_queue_ethernet_frame()

int router_queue_ethernet_frame	(	struct sr_instance *	router,
		struct sr_rt *	rti,
		struct sr_if *	intf,
		uint16_t	type,
		uint8_t *	payload,
		unsigned	payload_len
	)

Constructs an ethernet packet to the correct MAC address - if this exists in the cache the packet can be sent immediately, otherwise it must be queued while the ARP cache resolves the next hop IP address's MAC address; You are responsible for writing this.

Parameters

router	the router instance
rti	the routing table
intf	the outgoing interface
type	the type of ethernet traffic
payload	the packet to be encapsulated in an ethernet frame
payload_len	the size of the payload

◆ router_send_ethernet_frame()

int router_send_ethernet_frame	(	struct sr_instance *	router,
		uint32_t	dst_ip,
		uint16_t	type,
		uint8_t *	payload,
		unsigned	len
	)

Searches the routing table to find the correct interface on which to send the payload based on the destination IP, then queues the packet; This is already implemented for you.

Parameters

router	the router instance
dst_ip	the destination IP address
type	the type of ethernet traffic
payload	the packet to be encapsulated in an ethernet frame
len	the size of the payload

◆ sr_handlepacket()

void sr_handlepacket	(	struct sr_instance *	,
		uint8_t *	,
		unsigned	int,
		char *
	)

Called whenever an incoming packet is received; You are responsible for writing this.

This function checks that a received packet is well structured, decapsulates it, and then calls another handler based on the packet type.

◆ sr_send_packet()

int sr_send_packet	(	struct sr_instance *	sr,
		uint8_t *	buf,
		unsigned int	len,
		const char *	iface
	)

Send a packet (ethernet header included!) of length 'len' onto the wire.

Parameters

sr	the router instance
buf	the ethernet frame to be sent
len	the size of the ethernet frame
iface	the name of the outgoing interface

Classes

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ IPV4_HEADER_LEN

Function Documentation

◆ ether_to_me()

◆ handle_arp()

◆ handle_arpreq()

◆ handle_ip()

◆ icmp_send()

◆ ip_send_packet()

◆ ip_send_packet_from()

◆ ip_to_me()

◆ router_queue_ethernet_frame()

◆ router_send_ethernet_frame()

◆ sr_handlepacket()

◆ sr_send_packet()