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authorHannes Frederic Sowa <hannes@stressinduktion.org>2014-09-12 14:04:43 +0200
committerDavid S. Miller <davem@davemloft.net>2014-09-13 17:07:21 -0400
commit233577a22089facf5271ab5e845b2262047c971f (patch)
treec93ec43dbf3adb316b3af67a3d315984b3cc5f10 /net/core
parentac7a04c33dd7f8e429df4b929ba3a3e8e729cc89 (diff)
downloadlinux-233577a22089facf5271ab5e845b2262047c971f.tar.bz2
net: filter: constify detection of pkt_type_offset
Currently we have 2 pkt_type_offset functions doing the same thing and spread across the architecture files. Remove those and replace them with a PKT_TYPE_OFFSET macro helper which gets the constant value from a zero sized sk_buff member right in front of the bitfield with offsetof. This new offset marker does not change size of struct sk_buff. Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c31
1 files changed, 2 insertions, 29 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index dfc716ffa44b..601f28de7311 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -87,30 +87,6 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(sk_filter);
-/* Helper to find the offset of pkt_type in sk_buff structure. We want
- * to make sure its still a 3bit field starting at a byte boundary;
- * taken from arch/x86/net/bpf_jit_comp.c.
- */
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX (7 << 5)
-#else
-#define PKT_TYPE_MAX 7
-#endif
-static unsigned 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 %s, as pkt_type couldn't be found!\n", __func__);
- return -1;
-}
-
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);
@@ -190,11 +166,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
- *insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
- pkt_type_offset());
- if (insn->off < 0)
- return false;
- insn++;
+ *insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
+ PKT_TYPE_OFFSET());
*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
#ifdef __BIG_ENDIAN_BITFIELD
insn++;