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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 /arch
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 'arch')
-rw-r--r--arch/mips/net/bpf_jit.c27
-rw-r--r--arch/s390/net/bpf_jit_comp.c35
2 files changed, 2 insertions, 60 deletions
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 0e97ccd29fe3..7edc08398c4a 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 +1311,7 @@ jmp_cmp:
case BPF_ANC | SKF_AD_PKTTYPE:
ctx->flags |= SEEN_SKB;
- off = pkt_type_offset();
-
- if (off < 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 555f5c7e83ab..c52ac77408ca 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -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;