From 9d66df9a9a45b9305a2daff8a3c09a28f2c78d83 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 3 Oct 2024 14:48:32 +1000 Subject: conf: Add command line switch to enable IP_FREEBIND socket option In a couple of recent reports, we've seen that it can be useful for pasta to forward ports from addresses which are not currently configured on the host, but might be in future. That can be done with the sysctl net.ipv4.ip_nonlocal_bind, but that does require CAP_NET_ADMIN to set in the first place. We can allow the same thing on a per-socket basis with the IP_FREEBIND (or IPV6_FREEBIND) socket option. Add a --freebind command line argument to enable this socket option on all listening sockets. Link: https://bugs.passt.top/show_bug.cgi?id=101 Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- passt.1 | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'passt.1') diff --git a/passt.1 b/passt.1 index 79d134d..5ac2962 100644 --- a/passt.1 +++ b/passt.1 @@ -327,6 +327,16 @@ namespace will be silently dropped. Disable Router Advertisements. Router Solicitations coming from guest or target namespace will be ignored. +.TP +.BR \-\-freebind +Allow any binding address to be specified for \fB-t\fR and \fB-u\fR +options. Usually binding addresses must be addresses currently +configured on the host. With \fB\-\-freebind\fR, the +\fBIP_FREEBIND\fR or \fBIPV6_FREEBIND\fR socket option is enabled +allowing any address to be used. This is typically used to bind +addresses which might be configured on the host in future, at which +point the forwarding will immediately start operating. + .TP .BR \-\-map-host-loopback " " \fIaddr Translate \fIaddr\fR to refer to the host. Packets from the guest to -- cgit v1.2.3