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Message-Id: <1409778511-21273-1-git-send-email-kda@linux-powerpc.org>
Date: Thu, 4 Sep 2014 01:08:31 +0400
From: Denis Kirjanov <kda@...ux-powerpc.org>
To: netdev@...r.kernel.org
Cc: Denis Kirjanov <kda@...ux-powerpc.org>,
Markos Chandras <markos.chandras@...tec.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Daniel Borkmann <dborkman@...hat.com>,
Alexei Starovoitov <alexei.starovoitov@...il.com>
Subject: [PATCH v2 net-next] net: filter: export pkt_type_offset() helper
Currently we have 2 pkt_type_offset functions doing
the same thing and spread across the architecture files.
Let's use the generic helper routine.
Signed-off-by: Denis Kirjanov <kda@...ux-powerpc.org>
Cc: Markos Chandras <markos.chandras@...tec.com>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: Daniel Borkmann <dborkman@...hat.com>
Cc: Alexei Starovoitov <alexei.starovoitov@...il.com>
V2: Initialize the pkt_type_offset through the pure_initcall()
---
arch/mips/net/bpf_jit.c | 27 ++-------------------------
arch/s390/net/bpf_jit_comp.c | 31 -------------------------------
include/linux/filter.h | 2 ++
net/core/filter.c | 16 +++++++++++++---
4 files changed, 17 insertions(+), 59 deletions(-)
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 05a5661..bb9b53f 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -765,27 +765,6 @@ static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset)
return (u64)err << 32 | ntohl(ret);
}
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX (7 << 5)
-#else
-#define PKT_TYPE_MAX 7
-#endif
-static int pkt_type_offset(void)
-{
- struct sk_buff skb_probe = {
- .pkt_type = ~0,
- };
- u8 *ct = (u8 *)&skb_probe;
- unsigned int off;
-
- for (off = 0; off < sizeof(struct sk_buff); off++) {
- if (ct[off] == PKT_TYPE_MAX)
- return off;
- }
- pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
- return -1;
-}
-
static int build_body(struct jit_ctx *ctx)
{
void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
@@ -1332,11 +1311,9 @@ jmp_cmp:
case BPF_ANC | SKF_AD_PKTTYPE:
ctx->flags |= SEEN_SKB;
- off = pkt_type_offset();
-
- if (off < 0)
+ if (pkt_type_offset < 0)
return -1;
- emit_load_byte(r_tmp, r_skb, off, ctx);
+ emit_load_byte(r_tmp, r_skb, pkt_type_offset, ctx);
/* Keep only the last 3 bits */
emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
#ifdef __BIG_ENDIAN_BITFIELD
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 61e45b7..caa0cab 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -223,37 +223,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
EMIT2(0x07fe);
}
-/* Helper to find the offset of pkt_type in sk_buff
- * Make sure its still a 3bit field starting at the MSBs within a byte.
- */
-#define PKT_TYPE_MAX 0xe0
-static int pkt_type_offset;
-
-static int __init bpf_pkt_type_offset_init(void)
-{
- struct sk_buff skb_probe = {
- .pkt_type = ~0,
- };
- char *ct = (char *)&skb_probe;
- int off;
-
- pkt_type_offset = -1;
- for (off = 0; off < sizeof(struct sk_buff); off++) {
- if (!ct[off])
- continue;
- if (ct[off] == PKT_TYPE_MAX)
- pkt_type_offset = off;
- else {
- /* Found non matching bit pattern, fix needed. */
- WARN_ON_ONCE(1);
- pkt_type_offset = -1;
- return -1;
- }
- }
- return 0;
-}
-device_initcall(bpf_pkt_type_offset_init);
-
/*
* make sure we dont leak kernel information to user
*/
diff --git a/include/linux/filter.h b/include/linux/filter.h
index a5227ab..6814b54 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -424,6 +424,8 @@ static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
return bpf_internal_load_pointer_neg_helper(skb, k, size);
}
+extern __read_mostly int pkt_type_offset;
+
#ifdef CONFIG_BPF_JIT
#include <stdarg.h>
#include <linux/linkage.h>
diff --git a/net/core/filter.c b/net/core/filter.c
index d814b8a..edd17f1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -96,21 +96,29 @@ EXPORT_SYMBOL(sk_filter);
#else
#define PKT_TYPE_MAX 7
#endif
-static unsigned int pkt_type_offset(void)
+
+__read_mostly int pkt_type_offset;
+
+static int __init init_pkt_type_offset(void)
{
struct sk_buff skb_probe = { .pkt_type = ~0, };
u8 *ct = (u8 *) &skb_probe;
unsigned int off;
+ pkt_type_offset = -1;
for (off = 0; off < sizeof(struct sk_buff); off++) {
- if (ct[off] == PKT_TYPE_MAX)
+ if (ct[off] == PKT_TYPE_MAX) {
+ pkt_type_offset = off;
return off;
+ }
}
pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__);
return -1;
}
+pure_initcall(init_pkt_type_offset);
+
static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
return __skb_get_poff((struct sk_buff *)(unsigned long) ctx);
@@ -190,8 +198,10 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
+ if (pkt_type_offset < 0)
+ return false;
*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
- pkt_type_offset());
+ pkt_type_offset);
if (insn->off < 0)
return false;
insn++;
--
2.0.0
--
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