    Neighbor discovery (RFC 4861)

Author: Mathilde Durvy mdurv.nosp@m.y@ci.nosp@m.sco.c.nosp@m.om; Julien Abeille jabei.nosp@m.lle@.nosp@m.cisco.nosp@m..com

#include <string.h>
#include "uip.h"
#include "uip-icmp6.h"
#include "uip-nd6.h"
#include "uip-ds6.h"
#include "random.h"
#include "net/ip/uip-debug.h"

Macros
#define	_DEBUG_ 0

#define	UIP_LOG(m)

#define	UIP_ND6_OPT_HDR_BUF ((uip_nd6_opt_hdr *)&uip_buf[uip_l2_l3_icmp_hdr_len + nd6_opt_offset])
	Pointer to ND option. More...

#define	UIP_ND6_OPT_MTU_BUF ((uip_nd6_opt_mtu *)&uip_buf[uip_l2_l3_icmp_hdr_len + nd6_opt_offset])

#define	UIP_ND6_OPT_PREFIX_BUF ((uip_nd6_opt_prefix_info *)&uip_buf[uip_l2_l3_icmp_hdr_len + nd6_opt_offset])

Pointers to the header structures.
All pointers except UIP_IP_BUF depend on uip_ext_len, which at packet reception, is the total length of the extension headers. The pointer to ND6 options header also depends on nd6_opt_offset, which we set in each function. Care should be taken when manipulating these buffers about the value of these length variables
#define	UIP_IP_BUF ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
	Pointer to IP header. More...

#define	UIP_ICMP_BUF ((struct uip_icmp_hdr *)&uip_buf[uip_l2_l3_hdr_len])
	Pointer to ICMP header. More...

#define	UIP_ND6_RS_BUF ((uip_nd6_rs *)&uip_buf[uip_l2_l3_icmp_hdr_len])

#define	UIP_ND6_RA_BUF ((uip_nd6_ra *)&uip_buf[uip_l2_l3_icmp_hdr_len])

#define	UIP_ND6_NS_BUF ((uip_nd6_ns *)&uip_buf[uip_l2_l3_icmp_hdr_len])

#define	UIP_ND6_NA_BUF ((uip_nd6_na *)&uip_buf[uip_l2_l3_icmp_hdr_len])

Functions
static void	create_llao (uint8_t *llao, uint8_t type)
	Pointer to an interface address. More...

static void	na_input (void)
	Neighbor Advertisement Processing. More...

static void	ns_input (void)

static void	rs_input (void)

	UIP_ICMP6_HANDLER (ns_input_handler, ICMP6_NS, UIP_ICMP6_HANDLER_CODE_ANY, ns_input)

	UIP_ICMP6_HANDLER (na_input_handler, ICMP6_NA, UIP_ICMP6_HANDLER_CODE_ANY, na_input)

	UIP_ICMP6_HANDLER (rs_input_handler, ICMP6_RS, UIP_ICMP6_HANDLER_CODE_ANY, rs_input)

void	uip_nd6_init ()
	Initialise the uIP ND core. More...

void	uip_nd6_ns_output (uip_ipaddr_t src, uip_ipaddr_t dest, uip_ipaddr_t *tgt)
	Send a neighbor solicitation, send a Neighbor Advertisement. More...

void	uip_nd6_ra_output (uip_ipaddr_t *dest)
	send a Router Advertisement More...

Variables
static uip_ds6_addr_t *	addr
	Pointer to a router list entry. More...

static uip_ds6_defrt_t *	defrt
	Pointer to a nbr cache entry. More...

static uip_ds6_nbr_t *	nbr
	Pointer to llao option in uip_buf. More...

static uint8_t *	nd6_opt_llao
	Offset from the end of the icmpv6 header to the option in uip_buf. More...

static uint8_t	nd6_opt_offset

static void create_llao	(	uint8_t *	llao,
		uint8_t	type
	)

static

Pointer to an interface address.

References uip_lladdr, UIP_LLADDR_LEN, UIP_ND6_OPT_DATA_OFFSET, UIP_ND6_OPT_LEN_OFFSET, UIP_ND6_OPT_LLAO_LEN, and UIP_ND6_OPT_TYPE_OFFSET.

Referenced by ns_input(), uip_nd6_ns_output(), and uip_nd6_ra_output().

static void na_input ( void )

static

Neighbor Advertisement Processing.

we might have to send a pkt that had been buffered while address resolution was performed (if we support buffering, see UIP_CONF_QUEUE_PKT)

As per RFC 4861, on link layer that have addresses, TLLAO options MUST be included when responding to multicast solicitations, SHOULD be included in response to unicast (here we assume it is for now)

NA can be received after sending NS for DAD, Address resolution or NUD. Can be unsolicited as well. It can trigger update of the state of the neighbor in the neighbor cache, router in the router list. If the NS was for DAD, it means DAD failed

References ADDR_TENTATIVE, uip_ds6_nbr::isrouter, NBR_INCOMPLETE, NBR_REACHABLE, NBR_STALE, nd6_opt_llao, nd6_opt_offset, uip_ds6_nbr::nscount, NULL, PRINT6ADDR, PRINTF, uip_ds6_nbr::reachable, uip_ds6_netif::reachable_time, uip_ds6_nbr::state, uip_ds6_addr::state, stimer_set(), uip_ds6_addr_lookup(), uip_ds6_defrt_lookup(), uip_ds6_defrt_rm(), uip_ds6_if, uip_ds6_nbr_get_ll(), uip_ds6_nbr_lookup(), UIP_ICMP_BUF, UIP_IP_BUF, uip_is_addr_mcast, uip_l3_icmp_hdr_len, uip_len, UIP_LLADDR_LEN, UIP_ND6_HOP_LIMIT, UIP_ND6_NA_BUF, UIP_ND6_NA_FLAG_OVERRIDE, UIP_ND6_NA_FLAG_ROUTER, UIP_ND6_NA_FLAG_SOLICITED, UIP_ND6_NA_LEN, UIP_ND6_OPT_DATA_OFFSET, UIP_ND6_OPT_HDR_BUF, UIP_ND6_OPT_TLLAO, uip_packetqueue_buf(), uip_packetqueue_buflen(), uip_packetqueue_free(), and UIP_STAT.

static void ns_input ( void )

static

do we do something here? we both are using the same address. If we are doing dad, we could cancel it, though we should receive a NA in response of DAD NS we sent, hence DAD will fail anyway. If we were not doing DAD, it means there is a duplicate in the network!

References ADDR_TENTATIVE, create_llao(), ICMP6_NA, uip_ds6_addr::ipaddr, NBR_INCOMPLETE, NBR_STALE, nd6_opt_llao, nd6_opt_offset, NULL, PRINT6ADDR, PRINTF, uip_ds6_nbr::state, uip_ds6_addr::state, uip_buf, uip_create_linklocal_allnodes_mcast, uip_ds6_addr_lookup(), uip_ds6_is_my_addr, uip_ds6_nbr_add(), uip_ds6_nbr_get_ll(), uip_ds6_nbr_lookup(), uip_ds6_select_src(), uip_ext_len, uip_icmp6chksum(), UIP_ICMP_BUF, UIP_ICMPH_LEN, UIP_IP_BUF, UIP_IPH_LEN, uip_is_addr_mcast, uip_is_addr_solicited_node, uip_is_addr_unspecified, uip_l2_l3_icmp_hdr_len, uip_l3_icmp_hdr_len, uip_len, UIP_LLADDR_LEN, UIP_ND6_HOP_LIMIT, UIP_ND6_NA_BUF, UIP_ND6_NA_FLAG_OVERRIDE, UIP_ND6_NA_FLAG_ROUTER, UIP_ND6_NA_FLAG_SOLICITED, UIP_ND6_NA_LEN, UIP_ND6_NS_BUF, UIP_ND6_NS_LEN, UIP_ND6_OPT_DATA_OFFSET, UIP_ND6_OPT_HDR_BUF, UIP_ND6_OPT_LLAO_LEN, UIP_ND6_OPT_SLLAO, UIP_ND6_OPT_TLLAO, UIP_PROTO_ICMP6, and UIP_STAT.