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Message-Id: <1426763414-10091-1-git-send-email-msekleta@redhat.com>
Date: Thu, 19 Mar 2015 12:10:14 +0100
From: Michal Sekletar <msekleta@...hat.com>
To: netdev@...r.kernel.org
Cc: Michal Sekletar <msekleta@...hat.com>,
Alexei Starovoitov <ast@...mgrid.com>,
Jiri Pirko <jpirko@...hat.com>,
Ralf Baechle <ralf@...ux-mips.org>,
Russell King <linux@....linux.org.uk>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH net-next v2] filter: introduce SKF_AD_VLAN_TPID BPF extension
If vlan offloading takes place then vlan header is removed from frame
and its contents, both vlan_tci and vlan_proto, is available to userspace via
TPACKET interface. However, only vlan_tci can be used in BPF filters.
This commit introduces new BPF extension. It makes possible to load value of
vlan_proto (vlan TPID) to register A.
Cc: Alexei Starovoitov <ast@...mgrid.com>
Cc: Jiri Pirko <jpirko@...hat.com>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Russell King <linux@....linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Michal Sekletar <msekleta@...hat.com>
---
Changes in v2:
* extension renamed to SKF_AD_VLAN_TPID
* alias vlan_avail maybe used in bpf_asm programs instead of vlan_pr
* fixes for jit compilers, vlan_proto is 16 bit not 32 bit wide
Documentation/networking/filter.txt | 3 ++-
arch/arm/net/bpf_jit_32.c | 6 ++++++
arch/mips/net/bpf_jit.c | 6 ++++++
arch/powerpc/net/bpf_jit_comp.c | 5 +++++
arch/s390/net/bpf_jit_comp.c | 5 +++++
arch/sparc/net/bpf_jit_comp.c | 3 +++
include/linux/filter.h | 1 +
include/uapi/linux/filter.h | 3 ++-
net/core/filter.c | 10 ++++++++++
tools/net/bpf_exp.l | 2 ++
tools/net/bpf_exp.y | 11 ++++++++++-
11 files changed, 52 insertions(+), 3 deletions(-)
diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt
index 9930ecfb..234577d 100644
--- a/Documentation/networking/filter.txt
+++ b/Documentation/networking/filter.txt
@@ -280,8 +280,9 @@ Possible BPF extensions are shown in the following table:
rxhash skb->hash
cpu raw_smp_processor_id()
vlan_tci skb_vlan_tag_get(skb)
- vlan_pr skb_vlan_tag_present(skb)
+ vlan_avail skb_vlan_tag_present(skb)
rand prandom_u32()
+ vlan_tpid skb->vlan_proto
These extensions can also be prefixed with '#'.
Examples for low-level BPF:
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index e1268f9..e057074 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -843,6 +843,12 @@ b_epilogue:
else
OP_IMM3(ARM_AND, r_A, r_A, VLAN_TAG_PRESENT, ctx);
break;
+ case BPF_ANC | SKF_AD_VLAN_TPID:
+ ctx->seen |= SEEN_SKB;
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+ off = offsetof(struct sk_buff, vlan_proto);
+ emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
+ break;
case BPF_ANC | SKF_AD_QUEUE:
ctx->seen |= SEEN_SKB;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 5d61393..ab902a6 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -1295,6 +1295,12 @@ jmp_cmp:
emit_sltu(r_A, r_zero, r_A, ctx);
}
break;
+ case BPF_ANC | SKF_AD_VLAN_TPID:
+ ctx->flags |= SEEN_SKB | SEEN_A;
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+ off = offsetof(struct sk_buff, vlan_proto);
+ emit_half_load(r_A, r_skb, off, ctx);
+ break;
case BPF_ANC | SKF_AD_PKTTYPE:
ctx->flags |= SEEN_SKB;
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 17cea18..5f18542 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -399,6 +399,11 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
PPC_SRWI(r_A, r_A, 12);
}
break;
+ case BPF_ANC | SKF_AD_VLAN_TPID:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+ PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
+ vlan_proto));
+ break;
case BPF_ANC | SKF_AD_QUEUE:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
queue_mapping) != 2);
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index bbd1981..f5281ab 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -722,6 +722,11 @@ call_fn: /* lg %r1,<d(function)>(%r13) */
EMIT4_DISP(0x88500000, 12);
}
break;
+ case BPF_ANC | SKF_AD_VLAN_TPID: /* A = skb->vlan_proto */
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+ /* icm %r5,3,<d(vlan_proto)>(%r2) */
+ EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_proto));
+ break;
case BPF_ANC | SKF_AD_PKTTYPE:
/* lhi %r5,0 */
EMIT4(0xa7580000);
diff --git a/arch/sparc/net/bpf_jit_comp.c b/arch/sparc/net/bpf_jit_comp.c
index 7931eee..d71b6fc 100644
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -624,6 +624,9 @@ void bpf_jit_compile(struct bpf_prog *fp)
emit_and(r_A, r_TMP, r_A);
}
break;
+ case BPF_ANC | SKF_AD_VLAN_TPID:
+ emit_skb_load16(vlan_proto, r_A);
+ break;
case BPF_LD | BPF_W | BPF_LEN:
emit_skb_load32(len, r_A);
break;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 9ee8c67..fa11b3a 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -454,6 +454,7 @@ static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
BPF_ANCILLARY(VLAN_TAG_PRESENT);
BPF_ANCILLARY(PAY_OFFSET);
BPF_ANCILLARY(RANDOM);
+ BPF_ANCILLARY(VLAN_TPID);
}
/* Fallthrough. */
default:
diff --git a/include/uapi/linux/filter.h b/include/uapi/linux/filter.h
index 47785d5..34c7936 100644
--- a/include/uapi/linux/filter.h
+++ b/include/uapi/linux/filter.h
@@ -77,7 +77,8 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
#define SKF_AD_VLAN_TAG_PRESENT 48
#define SKF_AD_PAY_OFFSET 52
#define SKF_AD_RANDOM 56
-#define SKF_AD_MAX 60
+#define SKF_AD_VLAN_TPID 60
+#define SKF_AD_MAX 64
#define SKF_NET_OFF (-0x100000)
#define SKF_LL_OFF (-0x200000)
diff --git a/net/core/filter.c b/net/core/filter.c
index b95ae7f..30229f8 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -277,6 +277,16 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
insn += cnt - 1;
break;
+ case SKF_AD_OFF + SKF_AD_VLAN_TPID:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+
+ /* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
+ *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, vlan_proto));
+ /* A = ntohs(A) [emitting a nop or swap16] */
+ *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
+ break;
+
case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
case SKF_AD_OFF + SKF_AD_NLATTR:
case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
diff --git a/tools/net/bpf_exp.l b/tools/net/bpf_exp.l
index 833a966..5795f0b 100644
--- a/tools/net/bpf_exp.l
+++ b/tools/net/bpf_exp.l
@@ -92,7 +92,9 @@ extern void yyerror(const char *str);
"#"?("cpu") { return K_CPU; }
"#"?("vlan_tci") { return K_VLANT; }
"#"?("vlan_pr") { return K_VLANP; }
+"#"?("vlan_avail") { return K_VLANP; }
"#"?("rand") { return K_RAND; }
+"#"?("vlan_tpid") { return K_VLANTPID; }
":" { return ':'; }
"," { return ','; }
diff --git a/tools/net/bpf_exp.y b/tools/net/bpf_exp.y
index e6306c5..82728f1 100644
--- a/tools/net/bpf_exp.y
+++ b/tools/net/bpf_exp.y
@@ -56,7 +56,7 @@ static void bpf_set_jmp_label(char *label, enum jmp_type type);
%token OP_LDXI
%token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
-%token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF K_RAND
+%token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF K_RAND K_VLANTPID
%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'
@@ -167,6 +167,9 @@ ldb
| OP_LDB K_RAND {
bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
SKF_AD_OFF + SKF_AD_RANDOM); }
+ | OP_LDB K_VLANTPID {
+ bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
+ SKF_AD_OFF + SKF_AD_VLAN_TPID); }
;
ldh
@@ -218,6 +221,9 @@ ldh
| OP_LDH K_RAND {
bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
SKF_AD_OFF + SKF_AD_RANDOM); }
+ | OP_LDH K_VLANTPID {
+ bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
+ SKF_AD_OFF + SKF_AD_VLAN_TPID); }
;
ldi
@@ -274,6 +280,9 @@ ld
| OP_LD K_RAND {
bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
SKF_AD_OFF + SKF_AD_RANDOM); }
+ | OP_LD K_VLANTPID {
+ bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
+ SKF_AD_OFF + SKF_AD_VLAN_TPID); }
| OP_LD 'M' '[' number ']' {
bpf_set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
| OP_LD '[' 'x' '+' number ']' {
--
1.8.3.1
--
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