On Wed, Mar 12, 2025 at 01:59:35PM -0700, Bobby Eshleman wrote:
From: Stefano Garzarella <sgarz...@redhat.com>

This patch adds a check of the "net" assigned to a socket during
the vsock_find_bound_socket() and vsock_find_connected_socket()
to support network namespace, allowing to share the same address
(cid, port) across different network namespaces.

This patch preserves old behavior, and does not yet bring up namespace
support fully.

Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>

I'd describe here a bit the new behaviour related to `fallback` that you developed.

Or we can split this patch in two patches, one with my changes without fallback, and another with fallback as you as author.

WDYT?


Signed-off-by: Bobby Eshleman <bobbyeshle...@gmail.com>
---
v1 -> v2:
* remove 'netns' module param
* remove vsock_net_eq()
* use vsock_global_net() for "global" namespace
* use fallback logic in socket lookup functions, giving precedence to
 non-global vsock namespaces

RFC -> v1
* added 'netns' module param
* added 'vsock_net_eq()' to check the "net" assigned to a socket
 only when 'netns' support is enabled
---
include/net/af_vsock.h                  |  7 +++--
net/vmw_vsock/af_vsock.c                | 55 ++++++++++++++++++++++++---------
net/vmw_vsock/hyperv_transport.c        |  2 +-
net/vmw_vsock/virtio_transport_common.c |  5 +--
net/vmw_vsock/vmci_transport.c          |  4 +--
5 files changed, 51 insertions(+), 22 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 
9e85424c834353d016a527070dd62e15ff3bfce1..41afbc18648c953da27a93571d408de968aa7668
 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -213,9 +213,10 @@ void vsock_enqueue_accept(struct sock *listener, struct 
sock *connected);
void vsock_insert_connected(struct vsock_sock *vsk);
void vsock_remove_bound(struct vsock_sock *vsk);
void vsock_remove_connected(struct vsock_sock *vsk);
-struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr);
+struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr, struct net 
*net);
struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
-                                        struct sockaddr_vm *dst);
+                                        struct sockaddr_vm *dst,
+                                        struct net *net);
void vsock_remove_sock(struct vsock_sock *vsk);
void vsock_for_each_connected_socket(struct vsock_transport *transport,
                                     void (*fn)(struct sock *sk));
@@ -255,4 +256,6 @@ static inline bool vsock_msgzerocopy_allow(const struct 
vsock_transport *t)
{
        return t->msgzerocopy_allow && t->msgzerocopy_allow();
}
+
+struct net *vsock_global_net(void);

If it just returns null, maybe we can make it inline here.

#endif /* __AF_VSOCK_H__ */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 
7e3db87ae4333cf63327ec105ca99253569bb9fe..d206489bf0a81cf989387c7c8063be91a7c21a7d
 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -235,37 +235,60 @@ static void __vsock_remove_connected(struct vsock_sock 
*vsk)
        sock_put(&vsk->sk);
}

-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+struct net *vsock_global_net(void)
{
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(vsock_global_net);
+
+static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr,
+                                             struct net *net)
+{

Please add a comment here to describe what fallback is used for.
And I would suggest also something on top of this file to explain a bit
how netns are handled in AF_VSOCK.

+       struct sock *fallback = NULL;
        struct vsock_sock *vsk;

        list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
-               if (vsock_addr_equals_addr(addr, &vsk->local_addr))
-                       return sk_vsock(vsk);
+               if (vsock_addr_equals_addr(addr, &vsk->local_addr)) {
+                       if (net_eq(net, sock_net(sk_vsock(vsk))))
+                               return sk_vsock(vsk);

+                       if (net_eq(net, vsock_global_net()))
+                               fallback = sk_vsock(vsk);
+               }
                if (addr->svm_port == vsk->local_addr.svm_port &&
                    (vsk->local_addr.svm_cid == VMADDR_CID_ANY ||
-                    addr->svm_cid == VMADDR_CID_ANY))
-                       return sk_vsock(vsk);
+                    addr->svm_cid == VMADDR_CID_ANY)) {
+                       if (net_eq(net, sock_net(sk_vsock(vsk))))
+                               return sk_vsock(vsk);
+
+                       if (net_eq(net, vsock_global_net()))
+                               fallback = sk_vsock(vsk);
+               }
        }

-       return NULL;
+       return fallback;
}

static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
-                                                 struct sockaddr_vm *dst)
+                                                 struct sockaddr_vm *dst,
+                                                 struct net *net)
{
+       struct sock *fallback = NULL;
        struct vsock_sock *vsk;

        list_for_each_entry(vsk, vsock_connected_sockets(src, dst),
                            connected_table) {
                if (vsock_addr_equals_addr(src, &vsk->remote_addr) &&
                    dst->svm_port == vsk->local_addr.svm_port) {
-                       return sk_vsock(vsk);
+                       if (net_eq(net, sock_net(sk_vsock(vsk))))
+                               return sk_vsock(vsk);
+
+                       if (net_eq(net, vsock_global_net()))
+                               fallback = sk_vsock(vsk);

This pattern seems to be repeated 3 times, can we make a function/macro?

                }
        }

-       return NULL;
+       return fallback;
}

static void vsock_insert_unbound(struct vsock_sock *vsk)
@@ -304,12 +327,12 @@ void vsock_remove_connected(struct vsock_sock *vsk)
}
EXPORT_SYMBOL_GPL(vsock_remove_connected);

-struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
+struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr, struct net *net)
{
        struct sock *sk;

        spin_lock_bh(&vsock_table_lock);
-       sk = __vsock_find_bound_socket(addr);
+       sk = __vsock_find_bound_socket(addr, net);
        if (sk)
                sock_hold(sk);

@@ -320,12 +343,13 @@ struct sock *vsock_find_bound_socket(struct sockaddr_vm 
*addr)
EXPORT_SYMBOL_GPL(vsock_find_bound_socket);

struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
-                                        struct sockaddr_vm *dst)
+                                        struct sockaddr_vm *dst,
+                                        struct net *net)
{
        struct sock *sk;

        spin_lock_bh(&vsock_table_lock);
-       sk = __vsock_find_connected_socket(src, dst);
+       sk = __vsock_find_connected_socket(src, dst, net);
        if (sk)
                sock_hold(sk);

@@ -644,6 +668,7 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
{
        static u32 port;
        struct sockaddr_vm new_addr;
+       struct net *net = sock_net(sk_vsock(vsk));

        if (!port)
                port = get_random_u32_above(LAST_RESERVED_PORT);
@@ -660,7 +685,7 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,

                        new_addr.svm_port = port++;

-                       if (!__vsock_find_bound_socket(&new_addr)) {
+                       if (!__vsock_find_bound_socket(&new_addr, net)) {
                                found = true;
                                break;
                        }
@@ -677,7 +702,7 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
                        return -EACCES;
                }

-               if (__vsock_find_bound_socket(&new_addr))
+               if (__vsock_find_bound_socket(&new_addr, net))
                        return -EADDRINUSE;
        }

diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 
31342ab502b4fc35feb812d2c94e0e35ded73771..253609898d24f8a484fcfc3296011c6f501a72a8
 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -313,7 +313,7 @@ static void hvs_open_connection(struct vmbus_channel *chan)
                return;

        hvs_addr_init(&addr, conn_from_host ? if_type : if_instance);
-       sk = vsock_find_bound_socket(&addr);
+       sk = vsock_find_bound_socket(&addr, NULL);
        if (!sk)
                return;

diff --git a/net/vmw_vsock/virtio_transport_common.c 
b/net/vmw_vsock/virtio_transport_common.c
index 
7f7de6d8809655fe522749fbbc9025df71f071bd..256d2a4fe482b3cb938a681b6924be69b2065616
 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1590,6 +1590,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
                               struct sk_buff *skb)
{
        struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
+       struct net *net = vsock_global_net();

Why using vsock_global_net() in virtio and directly NULL in the others transports?

        struct sockaddr_vm src, dst;
        struct vsock_sock *vsk;
        struct sock *sk;
@@ -1617,9 +1618,9 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
        /* The socket must be in connected or bound table
         * otherwise send reset back
         */
-       sk = vsock_find_connected_socket(&src, &dst);
+       sk = vsock_find_connected_socket(&src, &dst, net);
        if (!sk) {
-               sk = vsock_find_bound_socket(&dst);
+               sk = vsock_find_bound_socket(&dst, net);
                if (!sk) {
                        (void)virtio_transport_reset_no_sock(t, skb);
                        goto free_pkt;
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 
b370070194fa4ac0df45a073d389ffccf69a0029..373b9fe30a26c18aaa181fbc16db840d8f839b13
 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -703,9 +703,9 @@ static int vmci_transport_recv_stream_cb(void *data, struct 
vmci_datagram *dg)
        vsock_addr_init(&src, pkt->dg.src.context, pkt->src_port);
        vsock_addr_init(&dst, pkt->dg.dst.context, pkt->dst_port);

-       sk = vsock_find_connected_socket(&src, &dst);
+       sk = vsock_find_connected_socket(&src, &dst, NULL);
        if (!sk) {
-               sk = vsock_find_bound_socket(&dst);
+               sk = vsock_find_bound_socket(&dst, NULL);
                if (!sk) {
                        /* We could not find a socket for this specified
                         * address.  If this packet is a RST, we just drop it.

-- 2.47.1



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