From 6e1e44293ef991d8c946dd59fbbd65c54901b255 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 14 Nov 2024 14:33:10 +1100 Subject: ndp: Send unsolicited Router Advertisements Currently, our NDP implementation only sends Router Advertisements (RA) when it receives a Router Solicitation (RS) from the guest. However, RFC 4861 requires that we periodically send unsolicited RAs. Linux as a guest also requires this: it will send an RS when a link first comes up, but the route it gets from this will have a finite lifetime (we set this to 65535s, the maximum allowed, around 18 hours). When that expires the guest will not send a new RS, but instead expects the route to have been renewed (if still valid) by an unsolicited RA. Implement sending unsolicited RAs on a partially randomised timer, as required by RFC 4861. The RFC also specifies that solicited RAs should also be delayed, or even omitted, if the next unsolicited RA is soon enough. For now we don't do that, always sending an immediate RA in response to an RS. We can get away with this because in our use cases we expect to just have passt itself and the guest on the link, rather than a large broadcast domain. Link: https://github.com/kubevirt/kubevirt/issues/13191 Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- ndp.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'ndp.h') diff --git a/ndp.h b/ndp.h index abe6d02..41c2000 100644 --- a/ndp.h +++ b/ndp.h @@ -6,7 +6,10 @@ #ifndef NDP_H #define NDP_H +struct icmp6hdr; + int ndp(const struct ctx *c, const struct icmp6hdr *ih, const struct in6_addr *saddr, const struct pool *p); +void ndp_timer(const struct ctx *c, const struct timespec *now); #endif /* NDP_H */ -- cgit v1.2.3