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Message-ID: <20190530185709.1861867-1-jonathan.lemon@gmail.com>
Date: Thu, 30 May 2019 11:57:08 -0700
From: Jonathan Lemon <jonathan.lemon@...il.com>
To: <netdev@...r.kernel.org>, <bjorn.topel@...el.com>,
<magnus.karlsson@...el.com>
CC: <kernel-team@...com>
Subject: [PATCH v2 bpf-next 1/2] bpf: Allow bpf_map_lookup_elem() on an xskmap
Currently, the AF_XDP code uses a separate map in order to
determine if an xsk is bound to a queue. Instead of doing this,
have bpf_map_lookup_elem() return the queue_id, as a way of
indicating that there is a valid entry at the map index.
Rearrange some xdp_sock members to eliminate structure holes.
Signed-off-by: Jonathan Lemon <jonathan.lemon@...il.com>
---
include/net/xdp_sock.h | 6 +++---
kernel/bpf/verifier.c | 6 +++++-
kernel/bpf/xskmap.c | 4 +++-
.../selftests/bpf/verifier/prevent_map_lookup.c | 15 ---------------
4 files changed, 11 insertions(+), 20 deletions(-)
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index d074b6d60f8a..7d84b1da43d2 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -57,12 +57,12 @@ struct xdp_sock {
struct net_device *dev;
struct xdp_umem *umem;
struct list_head flush_node;
- u16 queue_id;
- struct xsk_queue *tx ____cacheline_aligned_in_smp;
- struct list_head list;
+ u32 queue_id;
bool zc;
/* Protects multiple processes in the control path */
struct mutex mutex;
+ struct xsk_queue *tx ____cacheline_aligned_in_smp;
+ struct list_head list;
/* Mutual exclusion of NAPI TX thread and sendmsg error paths
* in the SKB destructor callback.
*/
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2778417e6e0c..91c730f85e92 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2905,10 +2905,14 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
* appear.
*/
case BPF_MAP_TYPE_CPUMAP:
- case BPF_MAP_TYPE_XSKMAP:
if (func_id != BPF_FUNC_redirect_map)
goto error;
break;
+ case BPF_MAP_TYPE_XSKMAP:
+ if (func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_elem)
+ goto error;
+ break;
case BPF_MAP_TYPE_ARRAY_OF_MAPS:
case BPF_MAP_TYPE_HASH_OF_MAPS:
if (func_id != BPF_FUNC_map_lookup_elem)
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 686d244e798d..249b22089014 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -154,7 +154,9 @@ void __xsk_map_flush(struct bpf_map *map)
static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
{
- return ERR_PTR(-EOPNOTSUPP);
+ struct xdp_sock *xs = __xsk_map_lookup_elem(map, *(u32 *)key);
+
+ return xs ? &xs->queue_id : NULL;
}
static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
diff --git a/tools/testing/selftests/bpf/verifier/prevent_map_lookup.c b/tools/testing/selftests/bpf/verifier/prevent_map_lookup.c
index bbdba990fefb..da7a4b37cb98 100644
--- a/tools/testing/selftests/bpf/verifier/prevent_map_lookup.c
+++ b/tools/testing/selftests/bpf/verifier/prevent_map_lookup.c
@@ -28,21 +28,6 @@
.errstr = "cannot pass map_type 18 into func bpf_map_lookup_elem",
.prog_type = BPF_PROG_TYPE_SOCK_OPS,
},
-{
- "prevent map lookup in xskmap",
- .insns = {
- BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
- BPF_LD_MAP_FD(BPF_REG_1, 0),
- BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
- BPF_EXIT_INSN(),
- },
- .fixup_map_xskmap = { 3 },
- .result = REJECT,
- .errstr = "cannot pass map_type 17 into func bpf_map_lookup_elem",
- .prog_type = BPF_PROG_TYPE_XDP,
-},
{
"prevent map lookup in stack trace",
.insns = {
--
2.17.1
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