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network: ndisc: drop outdated settings before processing RA message

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Otherwise, e.g. if a router is replaced, then the previously received
settings may never dropped.

Follow-up for 2ccada8dc4.
This commit is contained in:
Yu Watanabe 2022-10-03 12:18:49 +09:00
parent 8d1babc51d
commit 94e6d37c2b
1 changed files with 71 additions and 12 deletions
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83
src/network/networkd-ndisc.c
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@ -372,7 +372,6 @@ static int ndisc_router_process_autonomous_prefix(Link *link, sd_ndisc_router *r
SET_FOREACH(a, addresses) {
_cleanup_(address_freep) Address *address = NULL;
Address *e;
r = address_new(&address);
if (r < 0)
@ -385,17 +384,6 @@ static int ndisc_router_process_autonomous_prefix(Link *link, sd_ndisc_router *r
address->lifetime_valid_usec = lifetime_valid_usec;
address->lifetime_preferred_usec = lifetime_preferred_usec;
/* See RFC4862, section 5.5.3.e. But the following logic is deviated from RFC4862 by
* honoring all valid lifetimes to improve the reaction of SLAAC to renumbering events.
* See draft-ietf-6man-slaac-renum-02, section 4.2. */
r = address_get(link, address, &e);
if (r >= 0) {
/* If the address is already assigned, but not valid anymore, then refuse to
* update the address, and it will be removed. */
if (e->lifetime_valid_usec < timestamp_usec)
continue;
}
r = ndisc_request_address(TAKE_PTR(address), link, rt);
if (r < 0)
return log_link_error_errno(link, r, "Could not request SLAAC address: %m");
@ -824,6 +812,68 @@ static int ndisc_router_process_options(Link *link, sd_ndisc_router *rt) {
}
}
static int ndisc_drop_outdated(Link *link, usec_t timestamp_usec) {
bool updated = false;
NDiscDNSSL *dnssl;
NDiscRDNSS *rdnss;
Address *address;
Route *route;
int r = 0, k;
assert(link);
/* If an address or friends is already assigned, but not valid anymore, then refuse to update it,
* and let's immediately remove it.
* See RFC4862, section 5.5.3.e. But the following logic is deviated from RFC4862 by honoring all
* valid lifetimes to improve the reaction of SLAAC to renumbering events.
* See draft-ietf-6man-slaac-renum-02, section 4.2. */
SET_FOREACH(route, link->routes) {
if (route->source != NETWORK_CONFIG_SOURCE_NDISC)
continue;
if (route->lifetime_usec >= timestamp_usec)
continue; /* the route is still valid */
k = route_remove_and_drop(route);
if (k < 0)
r = log_link_warning_errno(link, k, "Failed to remove outdated SLAAC route, ignoring: %m");
}
SET_FOREACH(address, link->addresses) {
if (address->source != NETWORK_CONFIG_SOURCE_NDISC)
continue;
if (address->lifetime_valid_usec >= timestamp_usec)
continue; /* the address is still valid */
k = address_remove_and_drop(address);
if (k < 0)
r = log_link_warning_errno(link, k, "Failed to remove outdated SLAAC address, ignoring: %m");
}
SET_FOREACH(rdnss, link->ndisc_rdnss) {
if (rdnss->lifetime_usec >= timestamp_usec)
continue; /* the DNS server is still valid */
free(set_remove(link->ndisc_rdnss, rdnss));
updated = true;
}
SET_FOREACH(dnssl, link->ndisc_dnssl) {
if (dnssl->lifetime_usec >= timestamp_usec)
continue; /* the DNS domain is still valid */
free(set_remove(link->ndisc_dnssl, dnssl));
updated = true;
}
if (updated)
link_dirty(link);
return r;
}
static int ndisc_start_dhcp6_client(Link *link, sd_ndisc_router *rt) {
int r;
@ -869,6 +919,7 @@ static int ndisc_start_dhcp6_client(Link *link, sd_ndisc_router *rt) {
static int ndisc_router_handler(Link *link, sd_ndisc_router *rt) {
struct in6_addr router;
usec_t timestamp_usec;
int r;
assert(link);
@ -890,6 +941,14 @@ static int ndisc_router_handler(Link *link, sd_ndisc_router *rt) {
return 0;
}
r = sd_ndisc_router_get_timestamp(rt, CLOCK_BOOTTIME, &timestamp_usec);
if (r < 0)
return r;
r = ndisc_drop_outdated(link, timestamp_usec);
if (r < 0)
return r;
r = ndisc_start_dhcp6_client(link, rt);
if (r < 0)
return r;