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ipv6: adjust MLD membership on address state changes

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If MLD support is enabled, each locally assigned IPv6 address in the
appropriate state must be a member of the solicited-node multicast
group corresponding to that address.  Ensure that this is always the
case by (re-)deciding on the membership upon every address state
change.  By doing so, this patch enforces that user-initiated state
changes to addresses (e.g., deletion) never cause a desynchronization
with the corresponding solicited-node multicast group membership,
thereby making such user-initiated state changes simpler and safer.
This commit is contained in:
David van Moolenbroek
2016-12-16 21:26:32 +00:00
committed by sg
parent d5bc856f45
commit 71810d0415
3 changed files with 44 additions and 13 deletions
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47
src/core/ipv6/nd6.c
View File

@@ -171,12 +171,6 @@ nd6_input(struct pbuf *p, struct netif *inp)
/* We are using a duplicate address. */
netif_ip6_addr_set_state(inp, i, IP6_ADDR_INVALID);
#if LWIP_IPV6_MLD
/* Leave solicited node multicast group. */
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(inp, i)->addr[3]);
mld6_leavegroup_netif(inp, &multicast_address);
#endif /* LWIP_IPV6_MLD */
#if LWIP_IPV6_AUTOCONFIG
/* Check to see if this address was autoconfigured. */
if (!ip6_addr_islinklocal(&target_address)) {
@@ -871,13 +865,6 @@ nd6_tmr(void)
netif_ip6_addr_set_state(netif, i, IP6_ADDR_PREFERRED);
/* @todo implement preferred and valid lifetimes. */
} else if (netif->flags & NETIF_FLAG_UP) {
#if LWIP_IPV6_MLD
if ((addr_state & IP6_ADDR_TENTATIVE_COUNT_MASK) == 0) {
/* Join solicited node multicast group. */
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, i)->addr[3]);
mld6_joingroup_netif(netif, &multicast_address);
}
#endif /* LWIP_IPV6_MLD */
/* Send a NS for this address. */
nd6_send_ns(netif, netif_ip6_addr(netif, i), ND6_SEND_FLAG_MULTICAST_DEST);
/* tentative: set next state by increasing by one */
@@ -2074,4 +2061,38 @@ nd6_cleanup_netif(struct netif *netif)
}
}
#if LWIP_IPV6_MLD
/**
* The state of a local IPv6 address entry is about to change. If needed, join
* or leave the solicited-node multicast group for the address.
*
* @param netif The netif that owns the address.
* @param addr_idx The index of the address.
* @param new_state The new (IP6_ADDR_) state for the address.
*/
void
nd6_adjust_mld_membership(struct netif *netif, s8_t addr_idx, u8_t new_state)
{
u8_t old_state, old_member, new_member;
old_state = netif_ip6_addr_state(netif, addr_idx);
/* Determine whether we were, and should be, a member of the solicited-node
* multicast group for this address. For tentative addresses, the group is
* not joined until the address enters the TENTATIVE_1 (or VALID) state. */
old_member = (old_state != IP6_ADDR_INVALID && old_state != IP6_ADDR_TENTATIVE);
new_member = (new_state != IP6_ADDR_INVALID && new_state != IP6_ADDR_TENTATIVE);
if (old_member != new_member) {
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, addr_idx)->addr[3]);
if (new_member) {
mld6_joingroup_netif(netif, &multicast_address);
} else {
mld6_leavegroup_netif(netif, &multicast_address);
}
}
}
#endif /* LWIP_IPV6_MLD */
#endif /* LWIP_IPV6 */