Re: [PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
On Mon, Aug 25, 2014 at 2:33 PM, Cong Wang wrote: > On Sun, Aug 24, 2014 at 1:21 PM, Alexei Starovoitov wrote: >> 'maps' is a generic storage of different types for sharing data between >> kernel >> and userspace. >> >> The maps are accessed from user space via BPF syscall, which has commands: >> >> - create a map with given type and attributes >> fd = bpf_map_create(map_type, struct nlattr *attr, int len) >> returns fd or negative error >> >> - lookup key in a given map referenced by fd >> err = bpf_map_lookup_elem(int fd, void *key, void *value) >> returns zero and stores found elem into value or negative error >> >> - create or update key/value pair in a given map >> err = bpf_map_update_elem(int fd, void *key, void *value) >> returns zero or negative error >> >> - find and delete element by key in a given map >> err = bpf_map_delete_elem(int fd, void *key) >> >> - iterate map elements (based on input key return next_key) >> err = bpf_map_get_next_key(int fd, void *key, void *next_key) > > > I think you need to document the bpf() syscall instead of wrappers on it, > from a developer's point of view. You will anyway need to document a new > syscall with a man page as a general rule. yep. I've mentioned before that man page is on todo list. I'm delaying writing it, because it's the most difficult part and I don't want to keep rewriting it when interface changes (like it did from global id to fd). Once implementation lands, manpage will be the highest priority. > In the changelog I mean something like: > > err = bpf(BPF_MAP_LOOKUP_ELEM, ...); Are you saying instead of: err = bpf_map_lookup_elem(int fd, void *key, void *value) write err = bpf(BPF_MAP_LOOKUP_ELEM, fd, key, value) in commit log? I think that style carries less information per line. For man page I'll document the syscall in a traditional way, but for commit log I like to have maximum info in the fewest lines. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
On Sun, Aug 24, 2014 at 1:21 PM, Alexei Starovoitov wrote: > 'maps' is a generic storage of different types for sharing data between kernel > and userspace. > > The maps are accessed from user space via BPF syscall, which has commands: > > - create a map with given type and attributes > fd = bpf_map_create(map_type, struct nlattr *attr, int len) > returns fd or negative error > > - lookup key in a given map referenced by fd > err = bpf_map_lookup_elem(int fd, void *key, void *value) > returns zero and stores found elem into value or negative error > > - create or update key/value pair in a given map > err = bpf_map_update_elem(int fd, void *key, void *value) > returns zero or negative error > > - find and delete element by key in a given map > err = bpf_map_delete_elem(int fd, void *key) > > - iterate map elements (based on input key return next_key) > err = bpf_map_get_next_key(int fd, void *key, void *next_key) I think you need to document the bpf() syscall instead of wrappers on it, from a developer's point of view. You will anyway need to document a new syscall with a man page as a general rule. In the changelog I mean something like: err = bpf(BPF_MAP_LOOKUP_ELEM, ...); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
On Sun, Aug 24, 2014 at 1:21 PM, Alexei Starovoitov a...@plumgrid.com wrote: 'maps' is a generic storage of different types for sharing data between kernel and userspace. The maps are accessed from user space via BPF syscall, which has commands: - create a map with given type and attributes fd = bpf_map_create(map_type, struct nlattr *attr, int len) returns fd or negative error - lookup key in a given map referenced by fd err = bpf_map_lookup_elem(int fd, void *key, void *value) returns zero and stores found elem into value or negative error - create or update key/value pair in a given map err = bpf_map_update_elem(int fd, void *key, void *value) returns zero or negative error - find and delete element by key in a given map err = bpf_map_delete_elem(int fd, void *key) - iterate map elements (based on input key return next_key) err = bpf_map_get_next_key(int fd, void *key, void *next_key) I think you need to document the bpf() syscall instead of wrappers on it, from a developer's point of view. You will anyway need to document a new syscall with a man page as a general rule. In the changelog I mean something like: err = bpf(BPF_MAP_LOOKUP_ELEM, ...); -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
On Mon, Aug 25, 2014 at 2:33 PM, Cong Wang cw...@twopensource.com wrote: On Sun, Aug 24, 2014 at 1:21 PM, Alexei Starovoitov a...@plumgrid.com wrote: 'maps' is a generic storage of different types for sharing data between kernel and userspace. The maps are accessed from user space via BPF syscall, which has commands: - create a map with given type and attributes fd = bpf_map_create(map_type, struct nlattr *attr, int len) returns fd or negative error - lookup key in a given map referenced by fd err = bpf_map_lookup_elem(int fd, void *key, void *value) returns zero and stores found elem into value or negative error - create or update key/value pair in a given map err = bpf_map_update_elem(int fd, void *key, void *value) returns zero or negative error - find and delete element by key in a given map err = bpf_map_delete_elem(int fd, void *key) - iterate map elements (based on input key return next_key) err = bpf_map_get_next_key(int fd, void *key, void *next_key) I think you need to document the bpf() syscall instead of wrappers on it, from a developer's point of view. You will anyway need to document a new syscall with a man page as a general rule. yep. I've mentioned before that man page is on todo list. I'm delaying writing it, because it's the most difficult part and I don't want to keep rewriting it when interface changes (like it did from global id to fd). Once implementation lands, manpage will be the highest priority. In the changelog I mean something like: err = bpf(BPF_MAP_LOOKUP_ELEM, ...); Are you saying instead of: err = bpf_map_lookup_elem(int fd, void *key, void *value) write err = bpf(BPF_MAP_LOOKUP_ELEM, fd, key, value) in commit log? I think that style carries less information per line. For man page I'll document the syscall in a traditional way, but for commit log I like to have maximum info in the fewest lines. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
The maps are accessed from user space via BPF syscall, which has commands:
- create a map with given type and attributes
fd = bpf_map_create(map_type, struct nlattr *attr, int len)
returns fd or negative error
- lookup key in a given map referenced by fd
err = bpf_map_lookup_elem(int fd, void *key, void *value)
returns zero and stores found elem into value or negative error
- create or update key/value pair in a given map
err = bpf_map_update_elem(int fd, void *key, void *value)
returns zero or negative error
- find and delete element by key in a given map
err = bpf_map_delete_elem(int fd, void *key)
- iterate map elements (based on input key return next_key)
err = bpf_map_get_next_key(int fd, void *key, void *next_key)
- close(fd) deletes the map
Signed-off-by: Alexei Starovoitov
---
include/linux/bpf.h |8 ++
include/uapi/linux/bpf.h | 25 ++
kernel/bpf/syscall.c | 198 ++
3 files changed, 231 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 607ca53fe2af..fd1ac4b5ba8b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -9,6 +9,7 @@
#include
#include
+#include
struct bpf_map;
struct nlattr;
@@ -18,6 +19,12 @@ struct bpf_map_ops {
/* funcs callable from userspace (via syscall) */
struct bpf_map *(*map_alloc)(struct nlattr *attrs[BPF_MAP_ATTR_MAX +
1]);
void (*map_free)(struct bpf_map *);
+ int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
+
+ /* funcs callable from userspace and from eBPF programs */
+ void *(*map_lookup_elem)(struct bpf_map *map, void *key);
+ int (*map_update_elem)(struct bpf_map *map, void *key, void *value);
+ int (*map_delete_elem)(struct bpf_map *map, void *key);
};
struct bpf_map {
@@ -38,5 +45,6 @@ struct bpf_map_type_list {
void bpf_register_map_type(struct bpf_map_type_list *tl);
void bpf_map_put(struct bpf_map *map);
+struct bpf_map *bpf_map_get(struct fd f);
#endif /* _LINUX_BPF_H */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index de21c8ecf0bb..f68edb2681f8 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -326,6 +326,31 @@ enum bpf_cmd {
* map is deleted when fd is closed
*/
BPF_MAP_CREATE,
+
+ /* lookup key in a given map
+* err = bpf_map_lookup_elem(int fd, void *key, void *value)
+* returns zero and stores found elem into value
+* or negative error
+*/
+ BPF_MAP_LOOKUP_ELEM,
+
+ /* create or update key/value pair in a given map
+* err = bpf_map_update_elem(int fd, void *key, void *value)
+* returns zero or negative error
+*/
+ BPF_MAP_UPDATE_ELEM,
+
+ /* find and delete elem by key in a given map
+* err = bpf_map_delete_elem(int fd, void *key)
+* returns zero or negative error
+*/
+ BPF_MAP_DELETE_ELEM,
+
+ /* lookup key in a given map and return next key
+* err = bpf_map_get_elem(int fd, void *key, void *next_key)
+* returns zero and stores next key or negative error
+*/
+ BPF_MAP_GET_NEXT_KEY,
};
enum bpf_map_attributes {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 04cdf7948f8f..45e100ece1b7 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -13,6 +13,7 @@
#include
#include
#include
+#include
static LIST_HEAD(bpf_map_types);
@@ -131,6 +132,189 @@ free_attr:
return err;
}
+/* if error is returned, fd is released.
+ * On success caller should complete fd access with matching fdput()
+ */
+struct bpf_map *bpf_map_get(struct fd f)
+{
+ struct bpf_map *map;
+
+ if (!f.file)
+ return ERR_PTR(-EBADF);
+
+ if (f.file->f_op != _map_fops) {
+ fdput(f);
+ return ERR_PTR(-EINVAL);
+ }
+
+ map = f.file->private_data;
+
+ return map;
+}
+
+static int map_lookup_elem(int ufd, void __user *ukey, void __user *uvalue)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_map *map;
+ void *key, *value;
+ int err;
+
+ map = bpf_map_get(f);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+
+ err = -ENOMEM;
+ key = kmalloc(map->key_size, GFP_USER);
+ if (!key)
+ goto err_put;
+
+ err = -EFAULT;
+ if (copy_from_user(key, ukey, map->key_size) != 0)
+ goto free_key;
+
+ err = -ESRCH;
+ rcu_read_lock();
+ value = map->ops->map_lookup_elem(map, key);
+ if (!value)
+ goto err_unlock;
+
+ err = -EFAULT;
+ if (copy_to_user(uvalue, value, map->value_size) != 0)
+ goto err_unlock;
+
+ err = 0;
+
+err_unlock:
+ rcu_read_unlock();
+free_key:
+ kfree(key);
+err_put:
[PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
The maps are accessed from user space via BPF syscall, which has commands:
- create a map with given type and attributes
fd = bpf_map_create(map_type, struct nlattr *attr, int len)
returns fd or negative error
- lookup key in a given map referenced by fd
err = bpf_map_lookup_elem(int fd, void *key, void *value)
returns zero and stores found elem into value or negative error
- create or update key/value pair in a given map
err = bpf_map_update_elem(int fd, void *key, void *value)
returns zero or negative error
- find and delete element by key in a given map
err = bpf_map_delete_elem(int fd, void *key)
- iterate map elements (based on input key return next_key)
err = bpf_map_get_next_key(int fd, void *key, void *next_key)
- close(fd) deletes the map
Signed-off-by: Alexei Starovoitov a...@plumgrid.com
---
include/linux/bpf.h |8 ++
include/uapi/linux/bpf.h | 25 ++
kernel/bpf/syscall.c | 198 ++
3 files changed, 231 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 607ca53fe2af..fd1ac4b5ba8b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -9,6 +9,7 @@
#include uapi/linux/bpf.h
#include linux/workqueue.h
+#include linux/file.h
struct bpf_map;
struct nlattr;
@@ -18,6 +19,12 @@ struct bpf_map_ops {
/* funcs callable from userspace (via syscall) */
struct bpf_map *(*map_alloc)(struct nlattr *attrs[BPF_MAP_ATTR_MAX +
1]);
void (*map_free)(struct bpf_map *);
+ int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
+
+ /* funcs callable from userspace and from eBPF programs */
+ void *(*map_lookup_elem)(struct bpf_map *map, void *key);
+ int (*map_update_elem)(struct bpf_map *map, void *key, void *value);
+ int (*map_delete_elem)(struct bpf_map *map, void *key);
};
struct bpf_map {
@@ -38,5 +45,6 @@ struct bpf_map_type_list {
void bpf_register_map_type(struct bpf_map_type_list *tl);
void bpf_map_put(struct bpf_map *map);
+struct bpf_map *bpf_map_get(struct fd f);
#endif /* _LINUX_BPF_H */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index de21c8ecf0bb..f68edb2681f8 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -326,6 +326,31 @@ enum bpf_cmd {
* map is deleted when fd is closed
*/
BPF_MAP_CREATE,
+
+ /* lookup key in a given map
+* err = bpf_map_lookup_elem(int fd, void *key, void *value)
+* returns zero and stores found elem into value
+* or negative error
+*/
+ BPF_MAP_LOOKUP_ELEM,
+
+ /* create or update key/value pair in a given map
+* err = bpf_map_update_elem(int fd, void *key, void *value)
+* returns zero or negative error
+*/
+ BPF_MAP_UPDATE_ELEM,
+
+ /* find and delete elem by key in a given map
+* err = bpf_map_delete_elem(int fd, void *key)
+* returns zero or negative error
+*/
+ BPF_MAP_DELETE_ELEM,
+
+ /* lookup key in a given map and return next key
+* err = bpf_map_get_elem(int fd, void *key, void *next_key)
+* returns zero and stores next key or negative error
+*/
+ BPF_MAP_GET_NEXT_KEY,
};
enum bpf_map_attributes {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 04cdf7948f8f..45e100ece1b7 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -13,6 +13,7 @@
#include linux/syscalls.h
#include net/netlink.h
#include linux/anon_inodes.h
+#include linux/file.h
static LIST_HEAD(bpf_map_types);
@@ -131,6 +132,189 @@ free_attr:
return err;
}
+/* if error is returned, fd is released.
+ * On success caller should complete fd access with matching fdput()
+ */
+struct bpf_map *bpf_map_get(struct fd f)
+{
+ struct bpf_map *map;
+
+ if (!f.file)
+ return ERR_PTR(-EBADF);
+
+ if (f.file-f_op != bpf_map_fops) {
+ fdput(f);
+ return ERR_PTR(-EINVAL);
+ }
+
+ map = f.file-private_data;
+
+ return map;
+}
+
+static int map_lookup_elem(int ufd, void __user *ukey, void __user *uvalue)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_map *map;
+ void *key, *value;
+ int err;
+
+ map = bpf_map_get(f);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+
+ err = -ENOMEM;
+ key = kmalloc(map-key_size, GFP_USER);
+ if (!key)
+ goto err_put;
+
+ err = -EFAULT;
+ if (copy_from_user(key, ukey, map-key_size) != 0)
+ goto free_key;
+
+ err = -ESRCH;
+ rcu_read_lock();
+ value = map-ops-map_lookup_elem(map, key);
+ if (!value)
+ goto err_unlock;
+
+ err = -EFAULT;
+ if (copy_to_user(uvalue, value, map-value_size) != 0)
+
