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Date: Wed, 27 May 2020 18:14:19 -0600
From: David Ahern <dsahern@...nel.org>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, brouer@...hat.com,
toke@...hat.com, daniel@...earbox.net, john.fastabend@...il.com,
ast@...nel.org, kafai@...com, songliubraving@...com, yhs@...com,
andriin@...com, dsahern@...il.com
Subject: [PATCH v2 bpf-next 1/5] devmap: Formalize map value as a named struct
From: David Ahern <dsahern@...il.com>
Add 'struct devmap_val' to the bpf uapi to formalize the
expected values that can be passed in for a DEVMAP.
Update devmap code to use the struct.
Signed-off-by: David Ahern <dsahern@...il.com>
---
include/uapi/linux/bpf.h | 5 ++++
kernel/bpf/devmap.c | 43 ++++++++++++++++++++--------------
tools/include/uapi/linux/bpf.h | 5 ++++
3 files changed, 35 insertions(+), 18 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 54b93f8b49b8..d27302ecaa9c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3625,6 +3625,11 @@ struct xdp_md {
__u32 rx_queue_index; /* rxq->queue_index */
};
+/* DEVMAP values */
+struct devmap_val {
+ __u32 ifindex; /* device index */
+};
+
enum sk_action {
SK_DROP = 0,
SK_PASS,
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index a51d9fb7a359..069a50113e26 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -66,6 +66,7 @@ struct bpf_dtab_netdev {
struct bpf_dtab *dtab;
struct rcu_head rcu;
unsigned int idx;
+ struct devmap_val val;
};
struct bpf_dtab {
@@ -110,7 +111,8 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
- attr->value_size != 4 || attr->map_flags & ~DEV_CREATE_FLAG_MASK)
+ attr->value_size > sizeof(struct devmap_val) ||
+ attr->map_flags & ~DEV_CREATE_FLAG_MASK)
return -EINVAL;
/* Lookup returns a pointer straight to dev->ifindex, so make sure the
@@ -472,18 +474,15 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
- struct net_device *dev = obj ? obj->dev : NULL;
- return dev ? &dev->ifindex : NULL;
+ return obj ? &obj->val : NULL;
}
static void *dev_map_hash_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_dtab_netdev *obj = __dev_map_hash_lookup_elem(map,
*(u32 *)key);
- struct net_device *dev = obj ? obj->dev : NULL;
-
- return dev ? &dev->ifindex : NULL;
+ return obj ? &obj->val : NULL;
}
static void __dev_map_entry_free(struct rcu_head *rcu)
@@ -541,7 +540,7 @@ static int dev_map_hash_delete_elem(struct bpf_map *map, void *key)
static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
struct bpf_dtab *dtab,
- u32 ifindex,
+ struct devmap_val *val,
unsigned int idx)
{
struct bpf_dtab_netdev *dev;
@@ -551,16 +550,18 @@ static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
if (!dev)
return ERR_PTR(-ENOMEM);
- dev->dev = dev_get_by_index(net, ifindex);
- if (!dev->dev) {
- kfree(dev);
- return ERR_PTR(-EINVAL);
- }
+ dev->dev = dev_get_by_index(net, val->ifindex);
+ if (!dev->dev)
+ goto err_out;
dev->idx = idx;
dev->dtab = dtab;
+ dev->val.ifindex = val->ifindex;
return dev;
+err_out:
+ kfree(dev);
+ return ERR_PTR(-EINVAL);
}
static int __dev_map_update_elem(struct net *net, struct bpf_map *map,
@@ -568,7 +569,7 @@ static int __dev_map_update_elem(struct net *net, struct bpf_map *map,
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct bpf_dtab_netdev *dev, *old_dev;
- u32 ifindex = *(u32 *)value;
+ struct devmap_val val = { };
u32 i = *(u32 *)key;
if (unlikely(map_flags > BPF_EXIST))
@@ -578,10 +579,13 @@ static int __dev_map_update_elem(struct net *net, struct bpf_map *map,
if (unlikely(map_flags == BPF_NOEXIST))
return -EEXIST;
- if (!ifindex) {
+ /* already verified value_size <= sizeof val */
+ memcpy(&val, value, map->value_size);
+
+ if (!val.ifindex) {
dev = NULL;
} else {
- dev = __dev_map_alloc_node(net, dtab, ifindex, i);
+ dev = __dev_map_alloc_node(net, dtab, &val, i);
if (IS_ERR(dev))
return PTR_ERR(dev);
}
@@ -609,12 +613,15 @@ static int __dev_map_hash_update_elem(struct net *net, struct bpf_map *map,
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct bpf_dtab_netdev *dev, *old_dev;
- u32 ifindex = *(u32 *)value;
+ struct devmap_val val = { };
u32 idx = *(u32 *)key;
unsigned long flags;
int err = -EEXIST;
- if (unlikely(map_flags > BPF_EXIST || !ifindex))
+ /* already verified value_size <= sizeof val */
+ memcpy(&val, value, map->value_size);
+
+ if (unlikely(map_flags > BPF_EXIST || !val.ifindex))
return -EINVAL;
spin_lock_irqsave(&dtab->index_lock, flags);
@@ -623,7 +630,7 @@ static int __dev_map_hash_update_elem(struct net *net, struct bpf_map *map,
if (old_dev && (map_flags & BPF_NOEXIST))
goto out_err;
- dev = __dev_map_alloc_node(net, dtab, ifindex, idx);
+ dev = __dev_map_alloc_node(net, dtab, &val, idx);
if (IS_ERR(dev)) {
err = PTR_ERR(dev);
goto out_err;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 54b93f8b49b8..d27302ecaa9c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3625,6 +3625,11 @@ struct xdp_md {
__u32 rx_queue_index; /* rxq->queue_index */
};
+/* DEVMAP values */
+struct devmap_val {
+ __u32 ifindex; /* device index */
+};
+
enum sk_action {
SK_DROP = 0,
SK_PASS,
--
2.21.1 (Apple Git-122.3)
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