From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>, <kernel-team@fb.com>,
<netdev@vger.kernel.org>
Subject: [PATCH bpf-next v2 3/4] bpf: INET_DIAG support in bpf_sk_storage
Date: Tue, 25 Feb 2020 15:04:21 -0800 [thread overview]
Message-ID: <20200225230421.1975729-1-kafai@fb.com> (raw)
In-Reply-To: <20200225230402.1974723-1-kafai@fb.com>
This patch adds INET_DIAG support to bpf_sk_storage.
1. Although this series adds bpf_sk_storage diag capability to inet sk,
bpf_sk_storage is in general applicable to all fullsock. Hence, the
bpf_sk_storage logic will operate on SK_DIAG_* nlattr. The caller
will pass in its specific nesting nlattr (e.g. INET_DIAG_*) as
the argument.
2. The request will be like:
INET_DIAG_REQ_SK_BPF_STORAGES (nla_nest) (defined in latter patch)
SK_DIAG_BPF_STORAGE_REQ_MAP_FD (nla_put_u32)
SK_DIAG_BPF_STORAGE_REQ_MAP_FD (nla_put_u32)
......
Considering there could have multiple bpf_sk_storages in a sk,
instead of reusing INET_DIAG_INFO ("ss -i"), the user can select
some specific bpf_sk_storage to dump by specifying an array of
SK_DIAG_BPF_STORAGE_REQ_MAP_FD.
If no SK_DIAG_BPF_STORAGE_REQ_MAP_FD is specified (i.e. an empty
INET_DIAG_REQ_SK_BPF_STORAGES), it will dump all bpf_sk_storages
of a sk.
3. The reply will be like:
INET_DIAG_BPF_SK_STORAGES (nla_nest) (defined in latter patch)
SK_DIAG_BPF_STORAGE (nla_nest)
SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
SK_DIAG_BPF_STORAGE (nla_nest)
SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
......
4. Unlike other INET_DIAG info of a sk which is pretty static, the size
required to dump the bpf_sk_storage(s) of a sk is dynamic as the
system adding more bpf_sk_storage_map. It is hard to set a static
min_dump_alloc size.
Hence, this series learns it at the runtime and adjust the
cb->min_dump_alloc as it iterates all sk(s) of a system. The
"unsigned int *res_diag_size" in bpf_sk_storage_diag_put()
is for this purpose.
The next patch will update the cb->min_dump_alloc as it
iterates the sk(s).
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
include/linux/bpf.h | 1 +
include/net/bpf_sk_storage.h | 27 ++++
include/uapi/linux/sock_diag.h | 26 +++
kernel/bpf/syscall.c | 15 ++
net/core/bpf_sk_storage.c | 283 ++++++++++++++++++++++++++++++++-
5 files changed, 346 insertions(+), 6 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1acd5bf70350..3b6973d4d6d5 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1023,6 +1023,7 @@ void __bpf_free_used_maps(struct bpf_prog_aux *aux,
void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock);
void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock);
+struct bpf_map *bpf_map_get(u32 ufd);
struct bpf_map *bpf_map_get_with_uref(u32 ufd);
struct bpf_map *__bpf_map_get(struct fd f);
void bpf_map_inc(struct bpf_map *map);
diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h
index 8e4f831d2e52..5036c94c0503 100644
--- a/include/net/bpf_sk_storage.h
+++ b/include/net/bpf_sk_storage.h
@@ -10,14 +10,41 @@ void bpf_sk_storage_free(struct sock *sk);
extern const struct bpf_func_proto bpf_sk_storage_get_proto;
extern const struct bpf_func_proto bpf_sk_storage_delete_proto;
+struct bpf_sk_storage_diag;
+struct sk_buff;
+struct nlattr;
+struct sock;
+
#ifdef CONFIG_BPF_SYSCALL
int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk);
+struct bpf_sk_storage_diag *
+bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs);
+void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag);
+int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
+ struct sock *sk, struct sk_buff *skb,
+ int stg_array_type,
+ unsigned int *res_diag_size);
#else
static inline int bpf_sk_storage_clone(const struct sock *sk,
struct sock *newsk)
{
return 0;
}
+static inline struct bpf_sk_storage_diag *
+bpf_sk_storage_diag_alloc(const struct nlattr *nla)
+{
+ return NULL;
+}
+static inline void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag)
+{
+}
+static inline int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
+ struct sock *sk, struct sk_buff *skb,
+ int stg_array_type,
+ unsigned int *res_diag_size)
+{
+ return 0;
+}
#endif
#endif /* _BPF_SK_STORAGE_H */
diff --git a/include/uapi/linux/sock_diag.h b/include/uapi/linux/sock_diag.h
index e5925009a652..5f74a5f6091d 100644
--- a/include/uapi/linux/sock_diag.h
+++ b/include/uapi/linux/sock_diag.h
@@ -36,4 +36,30 @@ enum sknetlink_groups {
};
#define SKNLGRP_MAX (__SKNLGRP_MAX - 1)
+enum {
+ SK_DIAG_BPF_STORAGE_REQ_NONE,
+ SK_DIAG_BPF_STORAGE_REQ_MAP_FD,
+ __SK_DIAG_BPF_STORAGE_REQ_MAX,
+};
+
+#define SK_DIAG_BPF_STORAGE_REQ_MAX (__SK_DIAG_BPF_STORAGE_REQ_MAX - 1)
+
+enum {
+ SK_DIAG_BPF_STORAGE_REP_NONE,
+ SK_DIAG_BPF_STORAGE,
+ __SK_DIAG_BPF_STORAGE_REP_MAX,
+};
+
+#define SK_DIAB_BPF_STORAGE_REP_MAX (__SK_DIAG_BPF_STORAGE_REP_MAX - 1)
+
+enum {
+ SK_DIAG_BPF_STORAGE_NONE,
+ SK_DIAG_BPF_STORAGE_PAD,
+ SK_DIAG_BPF_STORAGE_MAP_ID,
+ SK_DIAG_BPF_STORAGE_MAP_VALUE,
+ __SK_DIAG_BPF_STORAGE_MAX,
+};
+
+#define SK_DIAG_BPF_STORAGE_MAX (__SK_DIAG_BPF_STORAGE_MAX - 1)
+
#endif /* _UAPI__SOCK_DIAG_H__ */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a79743a89815..c536c65256ad 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -902,6 +902,21 @@ void bpf_map_inc_with_uref(struct bpf_map *map)
}
EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);
+struct bpf_map *bpf_map_get(u32 ufd)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_map *map;
+
+ map = __bpf_map_get(f);
+ if (IS_ERR(map))
+ return map;
+
+ bpf_map_inc(map);
+ fdput(f);
+
+ return map;
+}
+
struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
struct fd f = fdget(ufd);
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 3ab23f698221..3415a4896c59 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -8,6 +8,7 @@
#include <linux/bpf.h>
#include <net/bpf_sk_storage.h>
#include <net/sock.h>
+#include <uapi/linux/sock_diag.h>
#include <uapi/linux/btf.h>
static atomic_t cache_idx;
@@ -606,6 +607,14 @@ static void bpf_sk_storage_map_free(struct bpf_map *map)
kfree(map);
}
+/* U16_MAX is much more than enough for sk local storage
+ * considering a tcp_sock is ~2k.
+ */
+#define MAX_VALUE_SIZE \
+ min_t(u32, \
+ (KMALLOC_MAX_SIZE - MAX_BPF_STACK - sizeof(struct bpf_sk_storage_elem)), \
+ (U16_MAX - sizeof(struct bpf_sk_storage_elem)))
+
static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
{
if (attr->map_flags & ~SK_STORAGE_CREATE_FLAG_MASK ||
@@ -619,12 +628,7 @@ static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (attr->value_size >= KMALLOC_MAX_SIZE -
- MAX_BPF_STACK - sizeof(struct bpf_sk_storage_elem) ||
- /* U16_MAX is much more than enough for sk local storage
- * considering a tcp_sock is ~2k.
- */
- attr->value_size > U16_MAX - sizeof(struct bpf_sk_storage_elem))
+ if (attr->value_size > MAX_VALUE_SIZE)
return -E2BIG;
return 0;
@@ -910,3 +914,270 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = {
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_SOCKET,
};
+
+struct bpf_sk_storage_diag {
+ u32 nr_maps;
+ struct bpf_map *maps[];
+};
+
+/* The reply will be like:
+ * INET_DIAG_BPF_SK_STORAGES (nla_nest)
+ * SK_DIAG_BPF_STORAGE (nla_nest)
+ * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
+ * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
+ * SK_DIAG_BPF_STORAGE (nla_nest)
+ * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
+ * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
+ * ....
+ */
+static int nla_value_size(u32 value_size)
+{
+ /* SK_DIAG_BPF_STORAGE (nla_nest)
+ * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
+ * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
+ */
+ return nla_total_size(0) + nla_total_size(sizeof(u32)) +
+ nla_total_size_64bit(value_size);
+}
+
+void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag)
+{
+ u32 i;
+
+ if (!diag)
+ return;
+
+ for (i = 0; i < diag->nr_maps; i++)
+ bpf_map_put(diag->maps[i]);
+
+ kfree(diag);
+}
+EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_free);
+
+static bool diag_check_dup(const struct bpf_sk_storage_diag *diag,
+ const struct bpf_map *map)
+{
+ u32 i;
+
+ for (i = 0; i < diag->nr_maps; i++) {
+ if (diag->maps[i] == map)
+ return true;
+ }
+
+ return false;
+}
+
+struct bpf_sk_storage_diag *
+bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
+{
+ struct bpf_sk_storage_diag *diag;
+ struct nlattr *nla;
+ u32 nr_maps = 0;
+ int rem, err;
+
+ /* bpf_sk_storage_map is currently limited to CAP_SYS_ADMIN as
+ * the map_alloc_check() side also does.
+ */
+ if (!capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EPERM);
+
+ nla_for_each_nested(nla, nla_stgs, rem) {
+ if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD)
+ nr_maps++;
+ }
+
+ diag = kzalloc(sizeof(*diag) + sizeof(diag->maps[0]) * nr_maps,
+ GFP_KERNEL);
+ if (!diag)
+ return ERR_PTR(-ENOMEM);
+
+ nla_for_each_nested(nla, nla_stgs, rem) {
+ struct bpf_map *map;
+ int map_fd;
+
+ if (nla_type(nla) != SK_DIAG_BPF_STORAGE_REQ_MAP_FD)
+ continue;
+
+ map_fd = nla_get_u32(nla);
+ map = bpf_map_get(map_fd);
+ if (IS_ERR(map)) {
+ err = PTR_ERR(map);
+ goto err_free;
+ }
+ if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) {
+ bpf_map_put(map);
+ err = -EINVAL;
+ goto err_free;
+ }
+ if (diag_check_dup(diag, map)) {
+ bpf_map_put(map);
+ err = -EEXIST;
+ goto err_free;
+ }
+ diag->maps[diag->nr_maps++] = map;
+ }
+
+ return diag;
+
+err_free:
+ bpf_sk_storage_diag_free(diag);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
+
+static int diag_get(struct bpf_sk_storage_data *sdata, struct sk_buff *skb)
+{
+ struct nlattr *nla_stg, *nla_value;
+ struct bpf_sk_storage_map *smap;
+
+ /* It cannot exceed max nlattr's payload */
+ BUILD_BUG_ON(U16_MAX - NLA_HDRLEN < MAX_VALUE_SIZE);
+
+ nla_stg = nla_nest_start(skb, SK_DIAG_BPF_STORAGE);
+ if (!nla_stg)
+ return -EMSGSIZE;
+
+ smap = rcu_dereference(sdata->smap);
+ if (nla_put_u32(skb, SK_DIAG_BPF_STORAGE_MAP_ID, smap->map.id))
+ goto errout;
+
+ nla_value = nla_reserve_64bit(skb, SK_DIAG_BPF_STORAGE_MAP_VALUE,
+ smap->map.value_size,
+ SK_DIAG_BPF_STORAGE_PAD);
+ if (!nla_value)
+ goto errout;
+
+ if (map_value_has_spin_lock(&smap->map))
+ copy_map_value_locked(&smap->map, nla_data(nla_value),
+ sdata->data, true);
+ else
+ copy_map_value(&smap->map, nla_data(nla_value), sdata->data);
+
+ nla_nest_end(skb, nla_stg);
+ return 0;
+
+errout:
+ nla_nest_cancel(skb, nla_stg);
+ return -EMSGSIZE;
+}
+
+static int bpf_sk_storage_diag_put_all(struct sock *sk, struct sk_buff *skb,
+ int stg_array_type,
+ unsigned int *res_diag_size)
+{
+ /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
+ unsigned int diag_size = nla_total_size(0);
+ struct bpf_sk_storage *sk_storage;
+ struct bpf_sk_storage_elem *selem;
+ struct bpf_sk_storage_map *smap;
+ struct nlattr *nla_stgs;
+ unsigned int saved_len;
+ int err = 0;
+
+ rcu_read_lock();
+
+ sk_storage = rcu_dereference(sk->sk_bpf_storage);
+ if (!sk_storage || hlist_empty(&sk_storage->list)) {
+ rcu_read_unlock();
+ return 0;
+ }
+
+ nla_stgs = nla_nest_start(skb, stg_array_type);
+ if (!nla_stgs)
+ /* Continue to learn diag_size */
+ err = -EMSGSIZE;
+
+ saved_len = skb->len;
+ hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) {
+ smap = rcu_dereference(SDATA(selem)->smap);
+ diag_size += nla_value_size(smap->map.value_size);
+
+ if (nla_stgs && diag_get(SDATA(selem), skb))
+ /* Continue to learn diag_size */
+ err = -EMSGSIZE;
+ }
+
+ rcu_read_unlock();
+
+ if (nla_stgs) {
+ if (saved_len == skb->len)
+ nla_nest_cancel(skb, nla_stgs);
+ else
+ nla_nest_end(skb, nla_stgs);
+ }
+
+ if (diag_size == nla_total_size(0)) {
+ *res_diag_size = 0;
+ return 0;
+ }
+
+ *res_diag_size = diag_size;
+ return err;
+}
+
+int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
+ struct sock *sk, struct sk_buff *skb,
+ int stg_array_type,
+ unsigned int *res_diag_size)
+{
+ /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
+ unsigned int diag_size = nla_total_size(0);
+ struct bpf_sk_storage *sk_storage;
+ struct bpf_sk_storage_data *sdata;
+ struct nlattr *nla_stgs;
+ unsigned int saved_len;
+ int err = 0;
+ u32 i;
+
+ *res_diag_size = 0;
+
+ /* No map has been specified. Dump all. */
+ if (!diag->nr_maps)
+ return bpf_sk_storage_diag_put_all(sk, skb, stg_array_type,
+ res_diag_size);
+
+ rcu_read_lock();
+ sk_storage = rcu_dereference(sk->sk_bpf_storage);
+ if (!sk_storage || hlist_empty(&sk_storage->list)) {
+ rcu_read_unlock();
+ return 0;
+ }
+
+ nla_stgs = nla_nest_start(skb, stg_array_type);
+ if (!nla_stgs)
+ /* Continue to learn diag_size */
+ err = -EMSGSIZE;
+
+ saved_len = skb->len;
+ for (i = 0; i < diag->nr_maps; i++) {
+ sdata = __sk_storage_lookup(sk_storage,
+ (struct bpf_sk_storage_map *)diag->maps[i],
+ false);
+
+ if (!sdata)
+ continue;
+
+ diag_size += nla_value_size(diag->maps[i]->value_size);
+
+ if (nla_stgs && diag_get(sdata, skb))
+ /* Continue to learn diag_size */
+ err = -EMSGSIZE;
+ }
+ rcu_read_unlock();
+
+ if (nla_stgs) {
+ if (saved_len == skb->len)
+ nla_nest_cancel(skb, nla_stgs);
+ else
+ nla_nest_end(skb, nla_stgs);
+ }
+
+ if (diag_size == nla_total_size(0)) {
+ *res_diag_size = 0;
+ return 0;
+ }
+
+ *res_diag_size = diag_size;
+ return err;
+}
+EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_put);
--
2.17.1
next prev parent reply other threads:[~2020-02-25 23:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 23:04 [PATCH bpf-next v2 0/4] Provide bpf_sk_storage data in INET_DIAG Martin KaFai Lau
2020-02-25 23:04 ` [PATCH bpf-next v2 1/4] inet_diag: Refactor inet_sk_diag_fill(), dump(), and dump_one() Martin KaFai Lau
2020-02-25 23:04 ` [PATCH bpf-next v2 2/4] inet_diag: Move the INET_DIAG_REQ_BYTECODE nlattr to cb->data Martin KaFai Lau
2020-02-25 23:04 ` Martin KaFai Lau [this message]
2020-02-25 23:04 ` [PATCH bpf-next v2 4/4] bpf: inet_diag: Dump bpf_sk_storages in inet_diag_dump() Martin KaFai Lau
2020-02-26 17:21 ` Daniel Borkmann
2020-02-27 1:34 ` Martin KaFai Lau
2020-02-27 6:16 ` Yonghong Song
2020-02-27 23:45 ` Daniel Borkmann
2020-02-28 2:57 ` Alexei Starovoitov
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