xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

net: filter: constify detection of pkt_type_offset

Browse Source 
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>
This commit is contained in:
Hannes Frederic Sowa
2014-09-12 14:04:43 +02:00
committed by David S. Miller
parent ac7a04c33d
commit 233577a220
4 changed files with 14 additions and 89 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
arch/s390/net/bpf_jit_comp.c
View File

@@ -227,37 +227,6 @@ 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
*/
@@ -757,12 +726,10 @@ call_fn: /* lg %r1,<d(function)>(%r13) */
}
break;
case BPF_ANC | SKF_AD_PKTTYPE:
if (pkt_type_offset < 0)
goto out;
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* ic %r5,<d(pkt_type_offset)>(%r2) */
EMIT4_DISP(0x43502000, pkt_type_offset);
EMIT4_DISP(0x43502000, PKT_TYPE_OFFSET());
/* srl %r5,5 */
EMIT4_DISP(0x88500000, 5);
break;