On Tue, Sep 16, 2025 at 09:21:16PM +0200, Volker Diels-Grabsch wrote:
The new wording clarifies that we (1) use the broadcast MAC address only until we know the actual MAC address of the guest, and (2) our first packets will not necessarily "reach" the guest, in the sense of being processed rather than dropped. (Which is why we actively send an initial ARP and/or NDP message, to get the guest MAC address as soon as possible.)
Signed-off-by: Volker Diels-Grabsch
Reviewed-by: David Gibson
--- tap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tap.c b/tap.c index 0f8ee25..399eeaa 100644 --- a/tap.c +++ b/tap.c @@ -1512,9 +1512,9 @@ void tap_backend_init(struct ctx *c) case MODE_PASST: tap_sock_unix_init(c);
- /* In passt mode, we don't know the guest's MAC address until it - * sends us packets. Use the broadcast address so that our - * first packets will reach it. + /* In passt mode, we don't know the guest's MAC address until + * it sends us packets. Until then, use the broadcast address + * so that our first packets will have a chance to reach it. */ memcpy(&c->guest_mac, MAC_BROADCAST, sizeof(c->guest_mac)); break; -- 2.47.3
-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson