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-rw-r--r--include/linux/bpf-netns.h8
-rw-r--r--include/linux/bpf_types.h3
-rw-r--r--include/net/netns/bpf.h1
-rw-r--r--include/uapi/linux/bpf.h5
-rw-r--r--kernel/bpf/net_namespace.c244
-rw-r--r--kernel/bpf/syscall.c3
-rw-r--r--tools/include/uapi/linux/bpf.h5
7 files changed, 267 insertions, 2 deletions
diff --git a/include/linux/bpf-netns.h b/include/linux/bpf-netns.h
index f3aec3d79824..4052d649f36d 100644
--- a/include/linux/bpf-netns.h
+++ b/include/linux/bpf-netns.h
@@ -34,6 +34,8 @@ int netns_bpf_prog_query(const union bpf_attr *attr,
int netns_bpf_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog);
int netns_bpf_prog_detach(const union bpf_attr *attr);
+int netns_bpf_link_create(const union bpf_attr *attr,
+ struct bpf_prog *prog);
#else
static inline int netns_bpf_prog_query(const union bpf_attr *attr,
union bpf_attr __user *uattr)
@@ -51,6 +53,12 @@ static inline int netns_bpf_prog_detach(const union bpf_attr *attr)
{
return -EOPNOTSUPP;
}
+
+static inline int netns_bpf_link_create(const union bpf_attr *attr,
+ struct bpf_prog *prog)
+{
+ return -EOPNOTSUPP;
+}
#endif
#endif /* _BPF_NETNS_H */
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index fa8e1b552acd..a18ae82a298a 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -126,3 +126,6 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)
BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup)
#endif
BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter)
+#ifdef CONFIG_NET
+BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns)
+#endif
diff --git a/include/net/netns/bpf.h b/include/net/netns/bpf.h
index a858d1c5b166..a8dce2a380c8 100644
--- a/include/net/netns/bpf.h
+++ b/include/net/netns/bpf.h
@@ -12,6 +12,7 @@ struct bpf_prog;
struct netns_bpf {
struct bpf_prog __rcu *progs[MAX_NETNS_BPF_ATTACH_TYPE];
+ struct bpf_link *links[MAX_NETNS_BPF_ATTACH_TYPE];
};
#endif /* __NETNS_BPF_H__ */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index f862a58fb567..b9ed9f14f2a2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -237,6 +237,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_TRACING = 2,
BPF_LINK_TYPE_CGROUP = 3,
BPF_LINK_TYPE_ITER = 4,
+ BPF_LINK_TYPE_NETNS = 5,
MAX_BPF_LINK_TYPE,
};
@@ -3839,6 +3840,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 attach_type;
} cgroup;
+ struct {
+ __u32 netns_ino;
+ __u32 attach_type;
+ } netns;
};
} __attribute__((aligned(8)));
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
index b37d81450c3a..78cf061f8179 100644
--- a/kernel/bpf/net_namespace.c
+++ b/kernel/bpf/net_namespace.c
@@ -8,9 +8,140 @@
* Functions to manage BPF programs attached to netns
*/
+struct bpf_netns_link {
+ struct bpf_link link;
+ enum bpf_attach_type type;
+ enum netns_bpf_attach_type netns_type;
+
+ /* We don't hold a ref to net in order to auto-detach the link
+ * when netns is going away. Instead we rely on pernet
+ * pre_exit callback to clear this pointer. Must be accessed
+ * with netns_bpf_mutex held.
+ */
+ struct net *net;
+};
+
/* Protects updates to netns_bpf */
DEFINE_MUTEX(netns_bpf_mutex);
+/* Must be called with netns_bpf_mutex held. */
+static void __net_exit bpf_netns_link_auto_detach(struct bpf_link *link)
+{
+ struct bpf_netns_link *net_link =
+ container_of(link, struct bpf_netns_link, link);
+
+ net_link->net = NULL;
+}
+
+static void bpf_netns_link_release(struct bpf_link *link)
+{
+ struct bpf_netns_link *net_link =
+ container_of(link, struct bpf_netns_link, link);
+ enum netns_bpf_attach_type type = net_link->netns_type;
+ struct net *net;
+
+ /* Link auto-detached by dying netns. */
+ if (!net_link->net)
+ return;
+
+ mutex_lock(&netns_bpf_mutex);
+
+ /* Recheck after potential sleep. We can race with cleanup_net
+ * here, but if we see a non-NULL struct net pointer pre_exit
+ * has not happened yet and will block on netns_bpf_mutex.
+ */
+ net = net_link->net;
+ if (!net)
+ goto out_unlock;
+
+ net->bpf.links[type] = NULL;
+ RCU_INIT_POINTER(net->bpf.progs[type], NULL);
+
+out_unlock:
+ mutex_unlock(&netns_bpf_mutex);
+}
+
+static void bpf_netns_link_dealloc(struct bpf_link *link)
+{
+ struct bpf_netns_link *net_link =
+ container_of(link, struct bpf_netns_link, link);
+
+ kfree(net_link);
+}
+
+static int bpf_netns_link_update_prog(struct bpf_link *link,
+ struct bpf_prog *new_prog,
+ struct bpf_prog *old_prog)
+{
+ struct bpf_netns_link *net_link =
+ container_of(link, struct bpf_netns_link, link);
+ enum netns_bpf_attach_type type = net_link->netns_type;
+ struct net *net;
+ int ret = 0;
+
+ if (old_prog && old_prog != link->prog)
+ return -EPERM;
+ if (new_prog->type != link->prog->type)
+ return -EINVAL;
+
+ mutex_lock(&netns_bpf_mutex);
+
+ net = net_link->net;
+ if (!net || !check_net(net)) {
+ /* Link auto-detached or netns dying */
+ ret = -ENOLINK;
+ goto out_unlock;
+ }
+
+ old_prog = xchg(&link->prog, new_prog);
+ rcu_assign_pointer(net->bpf.progs[type], new_prog);
+ bpf_prog_put(old_prog);
+
+out_unlock:
+ mutex_unlock(&netns_bpf_mutex);
+ return ret;
+}
+
+static int bpf_netns_link_fill_info(const struct bpf_link *link,
+ struct bpf_link_info *info)
+{
+ const struct bpf_netns_link *net_link =
+ container_of(link, struct bpf_netns_link, link);
+ unsigned int inum = 0;
+ struct net *net;
+
+ mutex_lock(&netns_bpf_mutex);
+ net = net_link->net;
+ if (net && check_net(net))
+ inum = net->ns.inum;
+ mutex_unlock(&netns_bpf_mutex);
+
+ info->netns.netns_ino = inum;
+ info->netns.attach_type = net_link->type;
+ return 0;
+}
+
+static void bpf_netns_link_show_fdinfo(const struct bpf_link *link,
+ struct seq_file *seq)
+{
+ struct bpf_link_info info = {};
+
+ bpf_netns_link_fill_info(link, &info);
+ seq_printf(seq,
+ "netns_ino:\t%u\n"
+ "attach_type:\t%u\n",
+ info.netns.netns_ino,
+ info.netns.attach_type);
+}
+
+static const struct bpf_link_ops bpf_netns_link_ops = {
+ .release = bpf_netns_link_release,
+ .dealloc = bpf_netns_link_dealloc,
+ .update_prog = bpf_netns_link_update_prog,
+ .fill_link_info = bpf_netns_link_fill_info,
+ .show_fdinfo = bpf_netns_link_show_fdinfo,
+};
+
int netns_bpf_prog_query(const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
@@ -67,6 +198,13 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
net = current->nsproxy->net_ns;
mutex_lock(&netns_bpf_mutex);
+
+ /* Attaching prog directly is not compatible with links */
+ if (net->bpf.links[type]) {
+ ret = -EEXIST;
+ goto out_unlock;
+ }
+
switch (type) {
case NETNS_BPF_FLOW_DISSECTOR:
ret = flow_dissector_bpf_prog_attach(net, prog);
@@ -75,6 +213,7 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
ret = -EINVAL;
break;
}
+out_unlock:
mutex_unlock(&netns_bpf_mutex);
return ret;
@@ -86,6 +225,10 @@ static int __netns_bpf_prog_detach(struct net *net,
{
struct bpf_prog *attached;
+ /* Progs attached via links cannot be detached */
+ if (net->bpf.links[type])
+ return -EINVAL;
+
attached = rcu_dereference_protected(net->bpf.progs[type],
lockdep_is_held(&netns_bpf_mutex));
if (!attached)
@@ -111,13 +254,110 @@ int netns_bpf_prog_detach(const union bpf_attr *attr)
return ret;
}
+static int netns_bpf_link_attach(struct net *net, struct bpf_link *link,
+ enum netns_bpf_attach_type type)
+{
+ struct bpf_prog *prog;
+ int err;
+
+ mutex_lock(&netns_bpf_mutex);
+
+ /* Allow attaching only one prog or link for now */
+ if (net->bpf.links[type]) {
+ err = -E2BIG;
+ goto out_unlock;
+ }
+ /* Links are not compatible with attaching prog directly */
+ prog = rcu_dereference_protected(net->bpf.progs[type],
+ lockdep_is_held(&netns_bpf_mutex));
+ if (prog) {
+ err = -EEXIST;
+ goto out_unlock;
+ }
+
+ switch (type) {
+ case NETNS_BPF_FLOW_DISSECTOR:
+ err = flow_dissector_bpf_prog_attach(net, link->prog);
+ break;
+ default:
+ err = -EINVAL;
+ break;
+ }
+ if (err)
+ goto out_unlock;
+
+ net->bpf.links[type] = link;
+
+out_unlock:
+ mutex_unlock(&netns_bpf_mutex);
+ return err;
+}
+
+int netns_bpf_link_create(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+ enum netns_bpf_attach_type netns_type;
+ struct bpf_link_primer link_primer;
+ struct bpf_netns_link *net_link;
+ enum bpf_attach_type type;
+ struct net *net;
+ int err;
+
+ if (attr->link_create.flags)
+ return -EINVAL;
+
+ type = attr->link_create.attach_type;
+ netns_type = to_netns_bpf_attach_type(type);
+ if (netns_type < 0)
+ return -EINVAL;
+
+ net = get_net_ns_by_fd(attr->link_create.target_fd);
+ if (IS_ERR(net))
+ return PTR_ERR(net);
+
+ net_link = kzalloc(sizeof(*net_link), GFP_USER);
+ if (!net_link) {
+ err = -ENOMEM;
+ goto out_put_net;
+ }
+ bpf_link_init(&net_link->link, BPF_LINK_TYPE_NETNS,
+ &bpf_netns_link_ops, prog);
+ net_link->net = net;
+ net_link->type = type;
+ net_link->netns_type = netns_type;
+
+ err = bpf_link_prime(&net_link->link, &link_primer);
+ if (err) {
+ kfree(net_link);
+ goto out_put_net;
+ }
+
+ err = netns_bpf_link_attach(net, &net_link->link, netns_type);
+ if (err) {
+ bpf_link_cleanup(&link_primer);
+ goto out_put_net;
+ }
+
+ put_net(net);
+ return bpf_link_settle(&link_primer);
+
+out_put_net:
+ put_net(net);
+ return err;
+}
+
static void __net_exit netns_bpf_pernet_pre_exit(struct net *net)
{
enum netns_bpf_attach_type type;
+ struct bpf_link *link;
mutex_lock(&netns_bpf_mutex);
- for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++)
- __netns_bpf_prog_detach(net, type);
+ for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++) {
+ link = net->bpf.links[type];
+ if (link)
+ bpf_netns_link_auto_detach(link);
+ else
+ __netns_bpf_prog_detach(net, type);
+ }
mutex_unlock(&netns_bpf_mutex);
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c77ab9c76f7b..e14a842d7e0d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3887,6 +3887,9 @@ static int link_create(union bpf_attr *attr)
case BPF_PROG_TYPE_TRACING:
ret = tracing_bpf_link_attach(attr, prog);
break;
+ case BPF_PROG_TYPE_FLOW_DISSECTOR:
+ ret = netns_bpf_link_create(attr, prog);
+ break;
default:
ret = -EINVAL;
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index f862a58fb567..b9ed9f14f2a2 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -237,6 +237,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_TRACING = 2,
BPF_LINK_TYPE_CGROUP = 3,
BPF_LINK_TYPE_ITER = 4,
+ BPF_LINK_TYPE_NETNS = 5,
MAX_BPF_LINK_TYPE,
};
@@ -3839,6 +3840,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 attach_type;
} cgroup;
+ struct {
+ __u32 netns_ino;
+ __u32 attach_type;
+ } netns;
};
} __attribute__((aligned(8)));
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 10:36:29 +0000