lwip nd没有实现ra，contik有参考
2024-08-30 12:14:22
lwip中关于nd的实现，没有路由器的功能，不能发送ra
在contiki中发现有nd发送ra的实现，
contiki/core/net/ipv6/uip-ds6.c
在rs的接收处理中，发送sollicited，在定时器中定期发送periodic。
发送solicted的时候，其实，是让定时器直接到时间实现的。
在uip_ds6_init中初始化ra发送定时器，初始设为2s后发送？等待链路本地地址有效
初始设置为2s，之后定时处理函数会处理定时器首次超时，处理完之后，会将定时器设置为RA间隔时间。
void
uip_ds6_init(void)
{
#if UIP_ND6_SEND_RA
stimer_set(&uip_ds6_timer_ra, 2); /* wait to have a link local IP address */
#endif /* UIP_ND6_SEND_RA */
在uip_ds6_periodic中定期处理是否超时，uip_ds6_periodic类似lwip中的nd_tmr。如果超时了，就发送uip_ds6_send_ra_periodic
void
uip_ds6_periodic(void)
{
#if UIP_CONF_ROUTER && UIP_ND6_SEND_RA
/* Periodic RA sending */
if(stimer_expired(&uip_ds6_timer_ra) && (uip_len == 0)) {
uip_ds6_send_ra_periodic();
}
#endif /* UIP_CONF_ROUTER && UIP_ND6_SEND_RA */
uip_ds6_send_ra_periodic函数中设置了两次随机时间，没看明白为什么？
第一次时间：间隔=最小间隔+随机数*（最大间隔-最小间隔）
第二次时间：初始的3次ra间隔不能超过初始最大间隔16s，后续的ra间隔没限制
/*---------------------------------------------------------------------------*/
void
uip_ds6_send_ra_periodic(void)
{
if(racount > ) {
/* send previously scheduled RA */
uip_nd6_ra_output(NULL);
PRINTF("Sending periodic RA\n");
}
/* rand_t = min + rand % (max - min) */
rand_time = UIP_ND6_MIN_RA_INTERVAL + random_rand() %
(uint16_t) (UIP_ND6_MAX_RA_INTERVAL - UIP_ND6_MIN_RA_INTERVAL);
PRINTF("Random time 1 = %u\n", rand_time);
/* intial ra interval = 16s, initial 3 ra, should not exceed initial_ra_interval */
if(racount < UIP_ND6_MAX_INITIAL_RAS) {
if(rand_time > UIP_ND6_MAX_INITIAL_RA_INTERVAL) {
rand_time = UIP_ND6_MAX_INITIAL_RA_INTERVAL;
PRINTF("Random time 2 = %u\n", rand_time);
}
racount++;
}
PRINTF("Random time 3 = %u\n", rand_time);
stimer_set(&uip_ds6_timer_ra, rand_time);
}
如果收到了rs（rs_input在uip-nd6.c文件中），则会发送sollicited的ra，在uip_ds6_send_ra_sollicited中，其实是直接将定时器设置到时间。
/*---------------------------------------------------------------------------*/
#if UIP_CONF_ROUTER
#if UIP_ND6_SEND_RA
void
uip_ds6_send_ra_sollicited(void)
{
/* We have a pb here: RA timer max possible value is 1800s,
* hence we have to use stimers. However, when receiving a RS, we
* should delay the reply by a random value between 0 and 500ms timers.
* stimers are in seconds, hence we cannot do this. Therefore we just send
* the RA (setting the timer to 0 below). We keep the code logic for
* the days contiki will support appropriate timers */
rand_time = ;
PRINTF("Solicited RA, random time %u\n", rand_time); if(stimer_remaining(&uip_ds6_timer_ra) > rand_time) {
if(stimer_elapsed(&uip_ds6_timer_ra) < UIP_ND6_MIN_DELAY_BETWEEN_RAS) {
/* Ensure that the RAs are rate limited */
/* stimer_set(&uip_ds6_timer_ra, rand_time +
UIP_ND6_MIN_DELAY_BETWEEN_RAS -
stimer_elapsed(&uip_ds6_timer_ra));
*/ } else {
stimer_set(&uip_ds6_timer_ra, rand_time);
}
}
}
uip-nd6.c实际的接收rs和发送ra在这个文件中定义
/*---------------------------------------------------------------------------*/
static void
rs_input(void)
{ PRINTF("Received RS from ");
PRINT6ADDR(&UIP_IP_BUF->srcipaddr);
PRINTF(" to ");
PRINT6ADDR(&UIP_IP_BUF->destipaddr);
PRINTF("\n");
UIP_STAT(++uip_stat.nd6.recv); #if UIP_CONF_IPV6_CHECKS
/*
* Check hop limit / icmp code
* target address must not be multicast
* if the NA is solicited, dest must not be multicast
*/
if((UIP_IP_BUF->ttl != UIP_ND6_HOP_LIMIT) || (UIP_ICMP_BUF->icode != )) {
PRINTF("RS received is bad\n");
goto discard;
}
#endif /*UIP_CONF_IPV6_CHECKS */ /* Only valid option is Source Link-Layer Address option any thing
else is discarded */
nd6_opt_offset = UIP_ND6_RS_LEN;
nd6_opt_llao = NULL; while(uip_l3_icmp_hdr_len + nd6_opt_offset < uip_len) {
#if UIP_CONF_IPV6_CHECKS
if(UIP_ND6_OPT_HDR_BUF->len == ) {
PRINTF("RS received is bad\n");
goto discard;
}
#endif /*UIP_CONF_IPV6_CHECKS */
switch (UIP_ND6_OPT_HDR_BUF->type) {
case UIP_ND6_OPT_SLLAO:
nd6_opt_llao = (uint8_t *)UIP_ND6_OPT_HDR_BUF;
break;
default:
PRINTF("ND option not supported in RS\n");
break;
}
nd6_opt_offset += (UIP_ND6_OPT_HDR_BUF->len << );
}
/* Options processing: only SLLAO */
if(nd6_opt_llao != NULL) {
#if UIP_CONF_IPV6_CHECKS
if(uip_is_addr_unspecified(&UIP_IP_BUF->srcipaddr)) {
PRINTF("RS received is bad\n");
goto discard;
} else {
#endif /*UIP_CONF_IPV6_CHECKS */
uip_lladdr_t lladdr_aligned;
extract_lladdr_from_llao_aligned(&lladdr_aligned);
if((nbr = uip_ds6_nbr_lookup(&UIP_IP_BUF->srcipaddr)) == NULL) {
/* we need to add the neighbor */
uip_ds6_nbr_add(&UIP_IP_BUF->srcipaddr, &lladdr_aligned,
, NBR_STALE, NBR_TABLE_REASON_IPV6_ND, NULL);
} else {
/* If LL address changed, set neighbor state to stale */
const uip_lladdr_t *lladdr = uip_ds6_nbr_get_ll(nbr);
if(lladdr == NULL) {
goto discard;
}
if(memcmp(&nd6_opt_llao[UIP_ND6_OPT_DATA_OFFSET],
lladdr, UIP_LLADDR_LEN) != ) {
uip_ds6_nbr_t nbr_data;
nbr_data = *nbr;
uip_ds6_nbr_rm(nbr);
nbr = uip_ds6_nbr_add(&UIP_IP_BUF->srcipaddr, &lladdr_aligned,
, NBR_STALE, NBR_TABLE_REASON_IPV6_ND, NULL);
nbr->reachable = nbr_data.reachable;
nbr->sendns = nbr_data.sendns;
nbr->nscount = nbr_data.nscount;
}
nbr->isrouter = ;
}
#if UIP_CONF_IPV6_CHECKS
}
#endif /*UIP_CONF_IPV6_CHECKS */
} /* Schedule a sollicited RA */
uip_ds6_send_ra_sollicited(); discard:
uip_clear_buf();
return;
}
/*---------------------------------------------------------------------------*/
void
uip_nd6_ra_output(uip_ipaddr_t * dest)
{ UIP_IP_BUF->vtc = 0x60;
UIP_IP_BUF->tcflow = ;
UIP_IP_BUF->flow = ;
UIP_IP_BUF->proto = UIP_PROTO_ICMP6;
UIP_IP_BUF->ttl = UIP_ND6_HOP_LIMIT; if(dest == NULL) {
uip_create_linklocal_allnodes_mcast(&UIP_IP_BUF->destipaddr);
} else {
/* For sollicited RA */
uip_ipaddr_copy(&UIP_IP_BUF->destipaddr, dest);
}
uip_ds6_select_src(&UIP_IP_BUF->srcipaddr, &UIP_IP_BUF->destipaddr); UIP_ICMP_BUF->type = ICMP6_RA;
UIP_ICMP_BUF->icode = ; UIP_ND6_RA_BUF->cur_ttl = uip_ds6_if.cur_hop_limit; UIP_ND6_RA_BUF->flags_reserved =
(UIP_ND6_M_FLAG << ) | (UIP_ND6_O_FLAG << ); UIP_ND6_RA_BUF->router_lifetime = uip_htons(UIP_ND6_ROUTER_LIFETIME);
//UIP_ND6_RA_BUF->reachable_time = uip_htonl(uip_ds6_if.reachable_time);
//UIP_ND6_RA_BUF->retrans_timer = uip_htonl(uip_ds6_if.retrans_timer);
UIP_ND6_RA_BUF->reachable_time = ;
UIP_ND6_RA_BUF->retrans_timer = ; uip_len = UIP_IPH_LEN + UIP_ICMPH_LEN + UIP_ND6_RA_LEN;
nd6_opt_offset = UIP_ND6_RA_LEN; /* Prefix list */
for(prefix = uip_ds6_prefix_list;
prefix < uip_ds6_prefix_list + UIP_DS6_PREFIX_NB; prefix++) {
if((prefix->isused) && (prefix->advertise)) {
UIP_ND6_OPT_PREFIX_BUF->type = UIP_ND6_OPT_PREFIX_INFO;
UIP_ND6_OPT_PREFIX_BUF->len = UIP_ND6_OPT_PREFIX_INFO_LEN / ;
UIP_ND6_OPT_PREFIX_BUF->preflen = prefix->length;
UIP_ND6_OPT_PREFIX_BUF->flagsreserved1 = prefix->l_a_reserved;
UIP_ND6_OPT_PREFIX_BUF->validlt = uip_htonl(prefix->vlifetime);
UIP_ND6_OPT_PREFIX_BUF->preferredlt = uip_htonl(prefix->plifetime);
UIP_ND6_OPT_PREFIX_BUF->reserved2 = ;
uip_ipaddr_copy(&(UIP_ND6_OPT_PREFIX_BUF->prefix), &(prefix->ipaddr));
nd6_opt_offset += UIP_ND6_OPT_PREFIX_INFO_LEN;
uip_len += UIP_ND6_OPT_PREFIX_INFO_LEN;
}
} /* Source link-layer option */
create_llao((uint8_t *)UIP_ND6_OPT_HDR_BUF, UIP_ND6_OPT_SLLAO); uip_len += UIP_ND6_OPT_LLAO_LEN;
nd6_opt_offset += UIP_ND6_OPT_LLAO_LEN; /* MTU */
UIP_ND6_OPT_MTU_BUF->type = UIP_ND6_OPT_MTU;
UIP_ND6_OPT_MTU_BUF->len = UIP_ND6_OPT_MTU_LEN >> ;
UIP_ND6_OPT_MTU_BUF->reserved = ;
//UIP_ND6_OPT_MTU_BUF->mtu = uip_htonl(uip_ds6_if.link_mtu);
UIP_ND6_OPT_MTU_BUF->mtu = uip_htonl(); uip_len += UIP_ND6_OPT_MTU_LEN;
nd6_opt_offset += UIP_ND6_OPT_MTU_LEN; #if UIP_ND6_RA_RDNSS
if(uip_nameserver_count() > ) {
uint8_t i = ;
uip_ipaddr_t *ip = &UIP_ND6_OPT_RDNSS_BUF->ip;
uip_ipaddr_t *dns = NULL;
UIP_ND6_OPT_RDNSS_BUF->type = UIP_ND6_OPT_RDNSS;
UIP_ND6_OPT_RDNSS_BUF->reserved = ;
UIP_ND6_OPT_RDNSS_BUF->lifetime = uip_nameserver_next_expiration();
if(UIP_ND6_OPT_RDNSS_BUF->lifetime != UIP_NAMESERVER_INFINITE_LIFETIME) {
UIP_ND6_OPT_RDNSS_BUF->lifetime -= clock_seconds();
}
while((dns = uip_nameserver_get(i)) != NULL) {
uip_ipaddr_copy(ip++, dns);
i++;
}
UIP_ND6_OPT_RDNSS_BUF->len = UIP_ND6_OPT_RDNSS_LEN + (i << );
PRINTF("%d nameservers reported\n", i);
uip_len += UIP_ND6_OPT_RDNSS_BUF->len << ;
nd6_opt_offset += UIP_ND6_OPT_RDNSS_BUF->len << ;
}
#endif /* UIP_ND6_RA_RDNSS */ UIP_IP_BUF->len[] = ((uip_len - UIP_IPH_LEN) >> );
UIP_IP_BUF->len[] = ((uip_len - UIP_IPH_LEN) & 0xff); /*ICMP checksum */
UIP_ICMP_BUF->icmpchksum = ;
UIP_ICMP_BUF->icmpchksum = ~uip_icmp6chksum(); UIP_STAT(++uip_stat.nd6.sent);
PRINTF("Sending RA to ");
PRINT6ADDR(&UIP_IP_BUF->destipaddr);
PRINTF(" from ");
PRINT6ADDR(&UIP_IP_BUF->srcipaddr);
PRINTF("\n");
return;
}
在linux和freebsd中每怎么找到发送ra的部分。
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