Host routes can include a preferred source address (RTA_PREFSRC), which must be one of the host's addresses. However when using pasta with -a the namespace might be given a different address, not on the host. This seems to occur pretty routinely depending on the network configuration systems in place on the host. With --config-net we will try to copy host routes to the namespace. If one of those includes an RTA_PREFSRC, but the namespace doesn't have the host address, this will fail with -EINVAL, causing pasta to fail. Fix this by stripping off RTA_PREFSRC attributes from routes as we copy them to the namespace. This is by no means infallible, bit it should at least handle common cases for the time being. Link: https://bugs.passt.top/show_bug.cgi?id=71 Link: https://github.com/containers/podman/pull/19699#issuecomment-1688769287 Signed-off-by: David Gibson --- netlink.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/netlink.c b/netlink.c index f55f2c3..98f08e7 100644 --- a/netlink.c +++ b/netlink.c @@ -462,8 +462,21 @@ int nl_route_dup(int s_src, unsigned int ifi_src, for (rta = RTM_RTA(rtm), na = RTM_PAYLOAD(nh); RTA_OK(rta, na); rta = RTA_NEXT(rta, na)) { - if (rta->rta_type == RTA_OIF) + if (rta->rta_type == RTA_OIF) { + /* The host obviously list's the host interface + * id here, we need to change it to the + * namespace's interface id + */ *(unsigned int *)RTA_DATA(rta) = ifi_dst; + } else if (rta->rta_type == RTA_PREFSRC) { + /* Host routes might include a preferred source + * address, which must be one of the host's + * addresses. However, with -a pasta will use a + * different namespace address, making such a + * route invalid in the namespace. Strip off + * RTA_PREFSRC attributes to avoid that. */ + rta->rta_type = RTA_UNSPEC; + } } } -- 2.41.0