We need to support (as best we can) older kernels which don't allow
unprivilieged processes to use the SO_BINDTODEVICE socket option.
Fallcaks for that case are controlled by the c->no_bindtodevice variable.
Currently testing behaviour of those fallbacks requires setting up a test
system with a kernel that doesn't support the option, which is pretty
awkward. We can test it almost as well and much more easily by adding a
command line option to explicitly disable use of SO_BINDTODEVICE.
Like --no-splice this is envisaged as something for developers' and
testers' convenience, not a supported option for end users. The man page
text reflects that.
Signed-off-by: David Gibson
---
conf.c | 2 ++
passt.1 | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/conf.c b/conf.c
index ceb9aa55..70ea168c 100644
--- a/conf.c
+++ b/conf.c
@@ -962,6 +962,7 @@ static void usage(const char *name, FILE *f, int status)
" --no-ndp Disable NDP responses\n"
" --no-dhcpv6 Disable DHCPv6 server\n"
" --no-ra Disable router advertisements\n"
+ " --no-bindtodevice Disable SO_BINDTODEVICE\n"
" --freebind Bind to any address for forwarding\n"
" --no-map-gw Don't map gateway address to host\n"
" -4, --ipv4-only Enable IPv4 operation only\n"
@@ -1454,6 +1455,7 @@ void conf(struct ctx *c, int argc, char **argv)
{"no-dhcpv6", no_argument, &c->no_dhcpv6, 1 },
{"no-ndp", no_argument, &c->no_ndp, 1 },
{"no-ra", no_argument, &c->no_ra, 1 },
+ {"no-bindtodevice", no_argument, &c->no_bindtodevice, 1},
{"no-splice", no_argument, &c->no_splice, 1 },
{"freebind", no_argument, &c->freebind, 1 },
{"no-map-gw", no_argument, &no_map_gw, 1 },
diff --git a/passt.1 b/passt.1
index db0d6620..4859d9e5 100644
--- a/passt.1
+++ b/passt.1
@@ -348,6 +348,12 @@ namespace will be silently dropped.
Disable Router Advertisements. Router Solicitations coming from guest or target
namespace will be ignored.
+.TP
+.BR \-\-no-bindtodevice
+Development/testing option, do not use. Disables use of
+SO_BINDTODEVICE socket option. Implicitly enabled on older kernels
+which don't permit unprivileged use of SO_BINDTODEVICE.
+
.TP
.BR \-\-freebind
Allow any binding address to be specified for \fB-t\fR and \fB-u\fR
--
2.52.0