From 9f368d9eb2c15ce38f5643174375f986795ce84c Mon Sep 17 00:00:00 2001 From: Yu Watanabe Date: Fri, 12 Apr 2024 04:24:57 +0900 Subject: [PATCH] network/ndisc: do nothing for existing routes if on-link flag is zero This effectively reverts commit 155d7a2c049cf866a0bfde8de371f09dfb3b6f29. From RFC 4861 section 6.3.4: > Note, however, that a Prefix Information option with the on-link flag > set to zero conveys no information concerning on-link determination and > MUST NOT be interpreted to mean that addresses covered by the prefix > are off-link. So, we should not drop previously configured routes when receieved a RA with Prefix Information option without on-link flag. Closes #28435. --- src/network/networkd-ndisc.c | 59 +++--------------------------------- 1 file changed, 4 insertions(+), 55 deletions(-) diff --git a/src/network/networkd-ndisc.c b/src/network/networkd-ndisc.c index 7f5577f6ae..65d2f82286 100644 --- a/src/network/networkd-ndisc.c +++ b/src/network/networkd-ndisc.c @@ -1231,56 +1231,6 @@ static int ndisc_router_process_onlink_prefix(Link *link, sd_ndisc_router *rt) { return 0; } -static int ndisc_router_drop_onlink_prefix(Link *link, sd_ndisc_router *rt) { - _cleanup_(route_unrefp) Route *route = NULL; - uint8_t prefixlen; - struct in6_addr prefix; - usec_t lifetime_usec; - int r; - - assert(link); - assert(link->network); - assert(rt); - - /* RFC 4861 section 6.3.4. - * Note, however, that a Prefix Information option with the on-link flag set to zero conveys no - * information concerning on-link determination and MUST NOT be interpreted to mean that addresses - * covered by the prefix are off-link. The only way to cancel a previous on-link indication is to - * advertise that prefix with the L-bit set and the Lifetime set to zero. */ - - if (!link->network->ndisc_use_onlink_prefix) - return 0; - - r = sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime_usec); - if (r < 0) - return log_link_warning_errno(link, r, "Failed to get prefix lifetime: %m"); - - if (lifetime_usec != 0) - return 0; - - r = sd_ndisc_router_prefix_get_address(rt, &prefix); - if (r < 0) - return log_link_warning_errno(link, r, "Failed to get prefix address: %m"); - - r = sd_ndisc_router_prefix_get_prefixlen(rt, &prefixlen); - if (r < 0) - return log_link_warning_errno(link, r, "Failed to get prefix length: %m"); - - r = route_new(&route); - if (r < 0) - return log_oom(); - - route->family = AF_INET6; - route->dst.in6 = prefix; - route->dst_prefixlen = prefixlen; - - r = ndisc_remove_route(route, link); - if (r < 0) - return log_link_warning_errno(link, r, "Could not remove prefix route: %m"); - - return 0; -} - static int ndisc_router_process_prefix(Link *link, sd_ndisc_router *rt) { uint8_t flags, prefixlen; struct in6_addr a; @@ -1319,12 +1269,11 @@ static int ndisc_router_process_prefix(Link *link, sd_ndisc_router *rt) { if (r < 0) return log_link_warning_errno(link, r, "Failed to get RA prefix flags: %m"); - if (FLAGS_SET(flags, ND_OPT_PI_FLAG_ONLINK)) + if (FLAGS_SET(flags, ND_OPT_PI_FLAG_ONLINK)) { r = ndisc_router_process_onlink_prefix(link, rt); - else - r = ndisc_router_drop_onlink_prefix(link, rt); - if (r < 0) - return r; + if (r < 0) + return r; + } if (FLAGS_SET(flags, ND_OPT_PI_FLAG_AUTO)) { r = ndisc_router_process_autonomous_prefix(link, rt); -- 2.25.1