On Tue, Dec 23, 2025 at 04:28:35PM -0800, Bobby Eshleman wrote: > From: Bobby Eshleman <[email protected]> > > Add the per-net vsock NS mode state. This only adds the structure for > holding the mode and some of the functions for setting/getting and > checking the mode, but does not integrate the functionality yet. > > Future patches add the uAPI and transport-specific usage of these > structures and helpers. > > Signed-off-by: Bobby Eshleman <[email protected]>
I do not much like splitting out functionality like this, myself - there's little to no docs and one can't figure out whether this code does what it is supposed to do without reading the next patch. I would just squash this with that one. If you are splitting functionality along some API lines, you need detailed docs so one can review implementation separately from use. > --- > Changes in v13: > - remove net_mode because net->vsock.mode becomes immutable, no need to > save the mode when vsocks are created. > - add the new helpers for child_ns_mode to support ns_mode inheriting > the mode from child_ns_mode. > - because ns_mode is immutable and child_ns_mode can be changed multiple > times, remove the write-once lock. > - simplify vsock_net_check_mode() to no longer take mode arguments since > the mode can be accessed via the net pointers without fear of the mode > changing. > - add logic in vsock_net_check_mode() to infer VSOCK_NET_MODE_GLOBAL > from NULL namespaces in order to allow only net pointers to be passed > to vsock_net_check_mode(), while still allowing namespace-unaware > transports to force global mode. > > Changes in v10: > - change mode_locked to int (Stefano) > > Changes in v9: > - use xchg(), WRITE_ONCE(), READ_ONCE() for mode and mode_locked (Stefano) > - clarify mode0/mode1 meaning in vsock_net_check_mode() comment > - remove spin lock in net->vsock (not used anymore) > - change mode from u8 to enum vsock_net_mode in vsock_net_write_mode() > > Changes in v7: > - clarify vsock_net_check_mode() comments > - change to `orig_net_mode == VSOCK_NET_MODE_GLOBAL && orig_net_mode == > vsk->orig_net_mode` > - remove extraneous explanation of `orig_net_mode` > - rename `written` to `mode_locked` > - rename `vsock_hdr` to `sysctl_hdr` > - change `orig_net_mode` to `net_mode` > - make vsock_net_check_mode() more generic by taking just net pointers > and modes, instead of a vsock_sock ptr, for reuse by transports > (e.g., vhost_vsock) > > Changes in v6: > - add orig_net_mode to store mode at creation time which will be used to > avoid breakage when namespace changes mode during socket/VM lifespan > > Changes in v5: > - use /proc/sys/net/vsock/ns_mode instead of /proc/net/vsock_ns_mode > - change from net->vsock.ns_mode to net->vsock.mode > - change vsock_net_set_mode() to vsock_net_write_mode() > - vsock_net_write_mode() returns bool for write success to avoid > need to use vsock_net_mode_can_set() > - remove vsock_net_mode_can_set() > --- > MAINTAINERS | 1 + > include/net/af_vsock.h | 42 ++++++++++++++++++++++++++++++++++++++++++ > include/net/net_namespace.h | 4 ++++ > include/net/netns/vsock.h | 17 +++++++++++++++++ > 4 files changed, 64 insertions(+) > > diff --git a/MAINTAINERS b/MAINTAINERS > index 454b8ed119e9..38d24e5a957c 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -27516,6 +27516,7 @@ L: [email protected] > S: Maintained > F: drivers/vhost/vsock.c > F: include/linux/virtio_vsock.h > +F: include/net/netns/vsock.h > F: include/uapi/linux/virtio_vsock.h > F: net/vmw_vsock/virtio_transport.c > F: net/vmw_vsock/virtio_transport_common.c > diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h > index d40e978126e3..6f5bc9dbefa5 100644 > --- a/include/net/af_vsock.h > +++ b/include/net/af_vsock.h > @@ -10,6 +10,7 @@ > > #include <linux/kernel.h> > #include <linux/workqueue.h> > +#include <net/netns/vsock.h> > #include <net/sock.h> > #include <uapi/linux/vm_sockets.h> > > @@ -256,4 +257,45 @@ static inline bool vsock_msgzerocopy_allow(const struct > vsock_transport *t) > { > return t->msgzerocopy_allow && t->msgzerocopy_allow(); > } > + > +static inline enum vsock_net_mode vsock_net_mode(struct net *net) > +{ > + return READ_ONCE(net->vsock.mode); > +} > + > +static inline void vsock_net_set_child_mode(struct net *net, > + enum vsock_net_mode mode) > +{ > + WRITE_ONCE(net->vsock.child_ns_mode, mode); > +} > + > +static inline enum vsock_net_mode vsock_net_child_mode(struct net *net) > +{ > + return READ_ONCE(net->vsock.child_ns_mode); > +} > + > +/* Return true if two namespaces pass the mode rules. Otherwise, return > false. > + * > + * A NULL namespace is treated as VSOCK_NET_MODE_GLOBAL. > + * > + * Read more about modes in the comment header of net/vmw_vsock/af_vsock.c. > + */ > +static inline bool vsock_net_check_mode(struct net *ns0, struct net *ns1) > +{ > + enum vsock_net_mode mode0, mode1; > + > + /* Any vsocks within the same network namespace are always reachable, > + * regardless of the mode. > + */ > + if (net_eq(ns0, ns1)) > + return true; > + > + mode0 = ns0 ? vsock_net_mode(ns0) : VSOCK_NET_MODE_GLOBAL; > + mode1 = ns1 ? vsock_net_mode(ns1) : VSOCK_NET_MODE_GLOBAL; > + > + /* Different namespaces are only reachable if they are both > + * global mode. > + */ > + return mode0 == VSOCK_NET_MODE_GLOBAL && mode0 == mode1; > +} > #endif /* __AF_VSOCK_H__ */ > diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h > index cb664f6e3558..66d3de1d935f 100644 > --- a/include/net/net_namespace.h > +++ b/include/net/net_namespace.h > @@ -37,6 +37,7 @@ > #include <net/netns/smc.h> > #include <net/netns/bpf.h> > #include <net/netns/mctp.h> > +#include <net/netns/vsock.h> > #include <net/net_trackers.h> > #include <linux/ns_common.h> > #include <linux/idr.h> > @@ -196,6 +197,9 @@ struct net { > /* Move to a better place when the config guard is removed. */ > struct mutex rtnl_mutex; > #endif > +#if IS_ENABLED(CONFIG_VSOCKETS) > + struct netns_vsock vsock; > +#endif > } __randomize_layout; > > #include <linux/seq_file_net.h> > diff --git a/include/net/netns/vsock.h b/include/net/netns/vsock.h > new file mode 100644 > index 000000000000..e2325e2d6ec5 > --- /dev/null > +++ b/include/net/netns/vsock.h > @@ -0,0 +1,17 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef __NET_NET_NAMESPACE_VSOCK_H > +#define __NET_NET_NAMESPACE_VSOCK_H > + > +#include <linux/types.h> > + > +enum vsock_net_mode { > + VSOCK_NET_MODE_GLOBAL, > + VSOCK_NET_MODE_LOCAL, > +}; > + > +struct netns_vsock { > + struct ctl_table_header *sysctl_hdr; > + enum vsock_net_mode mode; > + enum vsock_net_mode child_ns_mode; > +}; > +#endif /* __NET_NET_NAMESPACE_VSOCK_H */ > > -- > 2.47.3
