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authorJoe Stringer <joe@wand.net.nz>2018-11-30 15:32:20 -0800
committerAlexei Starovoitov <ast@kernel.org>2018-11-30 17:17:38 -0800
commitf71c6143c2038df1cb43a4b9c90740d14f77467c (patch)
treefef0cee90ee0a015b24c8916c6ccb3983b47d688 /include
parentb7df9ada9a7700dbcca1ba53d217c01e3d48179c (diff)
bpf: Support sk lookup in netns with id 0
David Ahern and Nicolas Dichtel report that the handling of the netns id 0 is incorrect for the BPF socket lookup helpers: rather than finding the netns with id 0, it is resolving to the current netns. This renders the netns_id 0 inaccessible. To fix this, adjust the API for the netns to treat all negative s32 values as a lookup in the current netns (including u64 values which when truncated to s32 become negative), while any values with a positive value in the signed 32-bit integer space would result in a lookup for a socket in the netns corresponding to that id. As before, if the netns with that ID does not exist, no socket will be found. Any netns outside of these ranges will fail to find a corresponding socket, as those values are reserved for future usage. Signed-off-by: Joe Stringer <joe@wand.net.nz> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Joey Pabalinas <joeypabalinas@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/uapi/linux/bpf.h35
1 files changed, 21 insertions, 14 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 426b5c8a245b..cba518c57229 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2170,7 +2170,7 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
- * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
+ * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
@@ -2187,12 +2187,14 @@ union bpf_attr {
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
- * If the *netns* is zero, then the socket lookup table in the
- * netns associated with the *ctx* will be used. For the TC hooks,
- * this in the netns of the device in the skb. For socket hooks,
- * this in the netns of the socket. If *netns* is non-zero, then
- * it specifies the ID of the netns relative to the netns
- * associated with the *ctx*.
+ * If the *netns* is a negative signed 32-bit integer, then the
+ * socket lookup table in the netns associated with the *ctx* will
+ * will be used. For the TC hooks, this is the netns of the device
+ * in the skb. For socket hooks, this is the netns of the socket.
+ * If *netns* is any other signed 32-bit value greater than or
+ * equal to zero then it specifies the ID of the netns relative to
+ * the netns associated with the *ctx*. *netns* values beyond the
+ * range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
@@ -2202,7 +2204,7 @@ union bpf_attr {
* Return
* Pointer to *struct bpf_sock*, or NULL in case of failure.
*
- * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
+ * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for UDP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
@@ -2219,12 +2221,14 @@ union bpf_attr {
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
- * If the *netns* is zero, then the socket lookup table in the
- * netns associated with the *ctx* will be used. For the TC hooks,
- * this in the netns of the device in the skb. For socket hooks,
- * this in the netns of the socket. If *netns* is non-zero, then
- * it specifies the ID of the netns relative to the netns
- * associated with the *ctx*.
+ * If the *netns* is a negative signed 32-bit integer, then the
+ * socket lookup table in the netns associated with the *ctx* will
+ * will be used. For the TC hooks, this is the netns of the device
+ * in the skb. For socket hooks, this is the netns of the socket.
+ * If *netns* is any other signed 32-bit value greater than or
+ * equal to zero then it specifies the ID of the netns relative to
+ * the netns associated with the *ctx*. *netns* values beyond the
+ * range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
@@ -2405,6 +2409,9 @@ enum bpf_func_id {
/* BPF_FUNC_perf_event_output for sk_buff input context. */
#define BPF_F_CTXLEN_MASK (0xfffffULL << 32)
+/* Current network namespace */
+#define BPF_F_CURRENT_NETNS (-1L)
+
/* Mode for BPF_FUNC_skb_adjust_room helper. */
enum bpf_adj_room_mode {
BPF_ADJ_ROOM_NET,