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authorAlexei Starovoitov <ast@plumgrid.com>2014-05-08 14:10:51 -0700
committerDavid S. Miller <davem@davemloft.net>2014-05-12 00:23:55 -0400
commit9739eef13c926645fbf88bcb77e66442fa75d688 (patch)
treed6934c95e5eae0027f755caf5ea7c1ab2aede94e /net/core/filter.c
parentMerge branch 'sctp_sysctl' (diff)
downloadlinux-dev-9739eef13c926645fbf88bcb77e66442fa75d688.tar.xz
linux-dev-9739eef13c926645fbf88bcb77e66442fa75d688.zip
net: filter: make BPF conversion more readable
Introduce BPF helper macros to define instructions (similar to old BPF_STMT/BPF_JUMP macros) Use them while converting classic BPF to internal and in BPF testsuite later. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/filter.c')
-rw-r--r--net/core/filter.c142
1 files changed, 50 insertions, 92 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index eb020a7d6f55..9aaa05ad8fe3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -668,10 +668,9 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_PROTOCOL:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
- insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, protocol);
+ /* A = *(u16 *) (ctx + offsetof(protocol)) */
+ *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, protocol));
insn++;
/* A = ntohs(A) [emitting a nop or swap16] */
@@ -681,37 +680,27 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
- insn->code = BPF_LDX | BPF_MEM | BPF_B;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = pkt_type_offset();
+ *insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
+ pkt_type_offset());
if (insn->off < 0)
return false;
insn++;
- insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = PKT_TYPE_MAX;
+ *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
break;
case SKF_AD_OFF + SKF_AD_IFINDEX:
case SKF_AD_OFF + SKF_AD_HATYPE:
- if (FIELD_SIZEOF(struct sk_buff, dev) == 8)
- insn->code = BPF_LDX | BPF_MEM | BPF_DW;
- else
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_REG_TMP;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, dev);
+ *insn = BPF_LDX_MEM(size_to_bpf(FIELD_SIZEOF(struct sk_buff, dev)),
+ BPF_REG_TMP, BPF_REG_CTX,
+ offsetof(struct sk_buff, dev));
insn++;
- insn->code = BPF_JMP | BPF_JNE | BPF_K;
- insn->a_reg = BPF_REG_TMP;
- insn->imm = 0;
- insn->off = 1;
+ /* if (tmp != 0) goto pc+1 */
+ *insn = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
insn++;
- insn->code = BPF_JMP | BPF_EXIT;
+ *insn = BPF_EXIT_INSN();
insn++;
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
@@ -732,55 +721,45 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_MARK:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, mark);
+ *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, mark));
break;
case SKF_AD_OFF + SKF_AD_RXHASH:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, hash);
+ *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, hash));
break;
case SKF_AD_OFF + SKF_AD_QUEUE:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
- insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, queue_mapping);
+ *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, queue_mapping));
break;
case SKF_AD_OFF + SKF_AD_VLAN_TAG:
case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
- insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, vlan_tci);
+ /* A = *(u16 *) (ctx + offsetof(vlan_tci)) */
+ *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, vlan_tci));
insn++;
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) {
- insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = ~VLAN_TAG_PRESENT;
+ *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A,
+ ~VLAN_TAG_PRESENT);
} else {
- insn->code = BPF_ALU | BPF_RSH | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = 12;
+ /* A >>= 12 */
+ *insn = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 12);
insn++;
- insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = 1;
+ /* A &= 1 */
+ *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 1);
}
break;
@@ -790,21 +769,15 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_CPU:
case SKF_AD_OFF + SKF_AD_RANDOM:
/* arg1 = ctx */
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_ARG1;
- insn->x_reg = BPF_REG_CTX;
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG1, BPF_REG_CTX);
insn++;
/* arg2 = A */
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_ARG2;
- insn->x_reg = BPF_REG_A;
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG2, BPF_REG_A);
insn++;
/* arg3 = X */
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_ARG3;
- insn->x_reg = BPF_REG_X;
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG3, BPF_REG_X);
insn++;
/* Emit call(ctx, arg2=A, arg3=X) */
@@ -829,9 +802,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
break;
case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
- insn->code = BPF_ALU | BPF_XOR | BPF_X;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_X;
+ /* A ^= X */
+ *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
break;
default:
@@ -897,9 +869,7 @@ do_pass:
fp = prog;
if (new_insn) {
- new_insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- new_insn->a_reg = BPF_REG_CTX;
- new_insn->x_reg = BPF_REG_ARG1;
+ *new_insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_CTX, BPF_REG_ARG1);
}
new_insn++;
@@ -1027,34 +997,28 @@ do_pass:
/* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
case BPF_LDX | BPF_MSH | BPF_B:
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_TMP;
- insn->x_reg = BPF_REG_A;
+ /* tmp = A */
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_TMP, BPF_REG_A);
insn++;
- insn->code = BPF_LD | BPF_ABS | BPF_B;
- insn->a_reg = BPF_REG_A;
- insn->imm = fp->k;
+ /* A = R0 = *(u8 *) (skb->data + K) */
+ *insn = BPF_LD_ABS(BPF_B, fp->k);
insn++;
- insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = 0xf;
+ /* A &= 0xf */
+ *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
insn++;
- insn->code = BPF_ALU | BPF_LSH | BPF_K;
- insn->a_reg = BPF_REG_A;
- insn->imm = 2;
+ /* A <<= 2 */
+ *insn = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
insn++;
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_X;
- insn->x_reg = BPF_REG_A;
+ /* X = A */
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_X, BPF_REG_A);
insn++;
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_TMP;
+ /* A = tmp */
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_A, BPF_REG_TMP);
break;
/* RET_K, RET_A are remaped into 2 insns. */
@@ -1068,7 +1032,7 @@ do_pass:
insn->imm = fp->k;
insn++;
- insn->code = BPF_JMP | BPF_EXIT;
+ *insn = BPF_EXIT_INSN();
break;
/* Store to stack. */
@@ -1102,16 +1066,12 @@ do_pass:
/* X = A */
case BPF_MISC | BPF_TAX:
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_X;
- insn->x_reg = BPF_REG_A;
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_X, BPF_REG_A);
break;
/* A = X */
case BPF_MISC | BPF_TXA:
- insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_X;
+ *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_A, BPF_REG_X);
break;
/* A = skb->len or X = skb->len */
@@ -1126,10 +1086,8 @@ do_pass:
/* access seccomp_data fields */
case BPF_LDX | BPF_ABS | BPF_W:
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_CTX;
- insn->off = fp->k;
+ /* A = *(u32 *) (ctx + K) */
+ *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
break;
default: