From 233577a22089facf5271ab5e845b2262047c971f Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Fri, 12 Sep 2014 14:04:43 +0200 Subject: 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 Cc: Markos Chandras Cc: Martin Schwidefsky Cc: Daniel Borkmann Cc: Alexei Starovoitov Signed-off-by: Denis Kirjanov Signed-off-by: Hannes Frederic Sowa Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- arch/mips/net/bpf_jit.c | 27 +-------------------------- arch/s390/net/bpf_jit_comp.c | 35 +---------------------------------- 2 files changed, 2 insertions(+), 60 deletions(-) (limited to 'arch') 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,(%r13) */ } break; case BPF_ANC | SKF_AD_PKTTYPE: - if (pkt_type_offset < 0) - goto out; /* lhi %r5,0 */ EMIT4(0xa7580000); /* ic %r5,(%r2) */ - EMIT4_DISP(0x43502000, pkt_type_offset); + EMIT4_DISP(0x43502000, PKT_TYPE_OFFSET()); /* srl %r5,5 */ EMIT4_DISP(0x88500000, 5); break; -- cgit v1.2.3