net: filter: split filter.c into two files

BPF is used in several kernel components. This split creates logical boundary
between generic eBPF core and the rest

kernel/bpf/core.c: eBPF interpreter

net/core/filter.c: classic->eBPF converter, classic verifiers, socket filters

This patch only moves functions.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 537 insertions, 0 deletions

diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
new file mode 100644
index 0000000..6a71145
--- /dev/null
+++ b/kernel/bpf/Makefile
@@ -0,0 +1 @@
+obj-y := core.o
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
new file mode 100644
index 0000000..77a240a
--- /dev/null
+++ b/kernel/bpf/core.c
@@ -0,0 +1,536 @@
+/*
+ * Linux Socket Filter - Kernel level socket filtering
+ *
+ * Based on the design of the Berkeley Packet Filter. The new
+ * internal format has been designed by PLUMgrid:
+ *
+ *	Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
+ *
+ * Authors:
+ *
+ *	Jay Schulist <jschlst@samba.org>
+ *	Alexei Starovoitov <ast@plumgrid.com>
+ *	Daniel Borkmann <dborkman@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Andi Kleen - Fix a few bad bugs and races.
+ * Kris Katterjohn - Added many additional checks in sk_chk_filter()
+ */
+#include <linux/filter.h>
+#include <linux/skbuff.h>
+#include <asm/unaligned.h>
+
+/* Registers */
+#define BPF_R0	regs[BPF_REG_0]
+#define BPF_R1	regs[BPF_REG_1]
+#define BPF_R2	regs[BPF_REG_2]
+#define BPF_R3	regs[BPF_REG_3]
+#define BPF_R4	regs[BPF_REG_4]
+#define BPF_R5	regs[BPF_REG_5]
+#define BPF_R6	regs[BPF_REG_6]
+#define BPF_R7	regs[BPF_REG_7]
+#define BPF_R8	regs[BPF_REG_8]
+#define BPF_R9	regs[BPF_REG_9]
+#define BPF_R10	regs[BPF_REG_10]
+
+/* Named registers */
+#define DST	regs[insn->dst_reg]
+#define SRC	regs[insn->src_reg]
+#define FP	regs[BPF_REG_FP]
+#define ARG1	regs[BPF_REG_ARG1]
+#define CTX	regs[BPF_REG_CTX]
+#define IMM	insn->imm
+
+/* No hurry in this branch
+ *
+ * Exported for the bpf jit load helper.
+ */
+void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
+{
+	u8 *ptr = NULL;
+
+	if (k >= SKF_NET_OFF)
+		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
+	else if (k >= SKF_LL_OFF)
+		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
+	if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
+		return ptr;
+
+	return NULL;
+}
+
+/* Base function for offset calculation. Needs to go into .text section,
+ * therefore keeping it non-static as well; will also be used by JITs
+ * anyway later on, so do not let the compiler omit it.
+ */
+noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+	return 0;
+}
+
+/**
+ *	__sk_run_filter - run a filter on a given context
+ *	@ctx: buffer to run the filter on
+ *	@insn: filter to apply
+ *
+ * Decode and apply filter instructions to the skb->data. Return length to
+ * keep, 0 for none. @ctx is the data we are operating on, @insn is the
+ * array of filter instructions.
+ */
+static unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn)
+{
+	u64 stack[MAX_BPF_STACK / sizeof(u64)];
+	u64 regs[MAX_BPF_REG], tmp;
+	static const void *jumptable[256] = {
+		[0 ... 255] = &&default_label,
+		/* Now overwrite non-defaults ... */
+		/* 32 bit ALU operations */
+		[BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
+		[BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
+		[BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
+		[BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
+		[BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
+		[BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
+		[BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
+		[BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
+		[BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
+		[BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
+		[BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
+		[BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
+		[BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
+		[BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
+		[BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
+		[BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
+		[BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
+		[BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
+		[BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
+		[BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
+		[BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
+		[BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
+		[BPF_ALU | BPF_NEG] = &&ALU_NEG,
+		[BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
+		[BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
+		/* 64 bit ALU operations */
+		[BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
+		[BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
+		[BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
+		[BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
+		[BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
+		[BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
+		[BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
+		[BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
+		[BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
+		[BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
+		[BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
+		[BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
+		[BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
+		[BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
+		[BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
+		[BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
+		[BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
+		[BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
+		[BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
+		[BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
+		[BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
+		[BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
+		[BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
+		[BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
+		[BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
+		/* Call instruction */
+		[BPF_JMP | BPF_CALL] = &&JMP_CALL,
+		/* Jumps */
+		[BPF_JMP | BPF_JA] = &&JMP_JA,
+		[BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
+		[BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
+		[BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
+		[BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
+		[BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
+		[BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
+		[BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
+		[BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
+		[BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
+		[BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
+		[BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
+		[BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
+		[BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
+		[BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
+		/* Program return */
+		[BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
+		/* Store instructions */
+		[BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
+		[BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
+		[BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
+		[BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
+		[BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
+		[BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
+		[BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
+		[BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
+		[BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
+		[BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
+		/* Load instructions */
+		[BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
+		[BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
+		[BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
+		[BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
+		[BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
+		[BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
+		[BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
+		[BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
+		[BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
+		[BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
+	};
+	void *ptr;
+	int off;
+
+#define CONT	 ({ insn++; goto select_insn; })
+#define CONT_JMP ({ insn++; goto select_insn; })
+
+	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
+	ARG1 = (u64) (unsigned long) ctx;
+
+	/* Registers used in classic BPF programs need to be reset first. */
+	regs[BPF_REG_A] = 0;
+	regs[BPF_REG_X] = 0;
+
+select_insn:
+	goto *jumptable[insn->code];
+
+	/* ALU */
+#define ALU(OPCODE, OP)			\
+	ALU64_##OPCODE##_X:		\
+		DST = DST OP SRC;	\
+		CONT;			\
+	ALU_##OPCODE##_X:		\
+		DST = (u32) DST OP (u32) SRC;	\
+		CONT;			\
+	ALU64_##OPCODE##_K:		\
+		DST = DST OP IMM;		\
+		CONT;			\
+	ALU_##OPCODE##_K:		\
+		DST = (u32) DST OP (u32) IMM;	\
+		CONT;
+
+	ALU(ADD,  +)
+	ALU(SUB,  -)
+	ALU(AND,  &)
+	ALU(OR,   |)
+	ALU(LSH, <<)
+	ALU(RSH, >>)
+	ALU(XOR,  ^)
+	ALU(MUL,  *)
+#undef ALU
+	ALU_NEG:
+		DST = (u32) -DST;
+		CONT;
+	ALU64_NEG:
+		DST = -DST;
+		CONT;
+	ALU_MOV_X:
+		DST = (u32) SRC;
+		CONT;
+	ALU_MOV_K:
+		DST = (u32) IMM;
+		CONT;
+	ALU64_MOV_X:
+		DST = SRC;
+		CONT;
+	ALU64_MOV_K:
+		DST = IMM;
+		CONT;
+	ALU64_ARSH_X:
+		(*(s64 *) &DST) >>= SRC;
+		CONT;
+	ALU64_ARSH_K:
+		(*(s64 *) &DST) >>= IMM;
+		CONT;
+	ALU64_MOD_X:
+		if (unlikely(SRC == 0))
+			return 0;
+		tmp = DST;
+		DST = do_div(tmp, SRC);
+		CONT;
+	ALU_MOD_X:
+		if (unlikely(SRC == 0))
+			return 0;
+		tmp = (u32) DST;
+		DST = do_div(tmp, (u32) SRC);
+		CONT;
+	ALU64_MOD_K:
+		tmp = DST;
+		DST = do_div(tmp, IMM);
+		CONT;
+	ALU_MOD_K:
+		tmp = (u32) DST;
+		DST = do_div(tmp, (u32) IMM);
+		CONT;
+	ALU64_DIV_X:
+		if (unlikely(SRC == 0))
+			return 0;
+		do_div(DST, SRC);
+		CONT;
+	ALU_DIV_X:
+		if (unlikely(SRC == 0))
+			return 0;
+		tmp = (u32) DST;
+		do_div(tmp, (u32) SRC);
+		DST = (u32) tmp;
+		CONT;
+	ALU64_DIV_K:
+		do_div(DST, IMM);
+		CONT;
+	ALU_DIV_K:
+		tmp = (u32) DST;
+		do_div(tmp, (u32) IMM);
+		DST = (u32) tmp;
+		CONT;
+	ALU_END_TO_BE:
+		switch (IMM) {
+		case 16:
+			DST = (__force u16) cpu_to_be16(DST);
+			break;
+		case 32:
+			DST = (__force u32) cpu_to_be32(DST);
+			break;
+		case 64:
+			DST = (__force u64) cpu_to_be64(DST);
+			break;
+		}
+		CONT;
+	ALU_END_TO_LE:
+		switch (IMM) {
+		case 16:
+			DST = (__force u16) cpu_to_le16(DST);
+			break;
+		case 32:
+			DST = (__force u32) cpu_to_le32(DST);
+			break;
+		case 64:
+			DST = (__force u64) cpu_to_le64(DST);
+			break;
+		}
+		CONT;
+
+	/* CALL */
+	JMP_CALL:
+		/* Function call scratches BPF_R1-BPF_R5 registers,
+		 * preserves BPF_R6-BPF_R9, and stores return value
+		 * into BPF_R0.
+		 */
+		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
+						       BPF_R4, BPF_R5);
+		CONT;
+
+	/* JMP */
+	JMP_JA:
+		insn += insn->off;
+		CONT;
+	JMP_JEQ_X:
+		if (DST == SRC) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JEQ_K:
+		if (DST == IMM) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JNE_X:
+		if (DST != SRC) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JNE_K:
+		if (DST != IMM) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JGT_X:
+		if (DST > SRC) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JGT_K:
+		if (DST > IMM) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JGE_X:
+		if (DST >= SRC) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JGE_K:
+		if (DST >= IMM) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSGT_X:
+		if (((s64) DST) > ((s64) SRC)) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSGT_K:
+		if (((s64) DST) > ((s64) IMM)) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSGE_X:
+		if (((s64) DST) >= ((s64) SRC)) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSGE_K:
+		if (((s64) DST) >= ((s64) IMM)) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSET_X:
+		if (DST & SRC) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_JSET_K:
+		if (DST & IMM) {
+			insn += insn->off;
+			CONT_JMP;
+		}
+		CONT;
+	JMP_EXIT:
+		return BPF_R0;
+
+	/* STX and ST and LDX*/
+#define LDST(SIZEOP, SIZE)						\
+	STX_MEM_##SIZEOP:						\
+		*(SIZE *)(unsigned long) (DST + insn->off) = SRC;	\
+		CONT;							\
+	ST_MEM_##SIZEOP:						\
+		*(SIZE *)(unsigned long) (DST + insn->off) = IMM;	\
+		CONT;							\
+	LDX_MEM_##SIZEOP:						\
+		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
+		CONT;
+
+	LDST(B,   u8)
+	LDST(H,  u16)
+	LDST(W,  u32)
+	LDST(DW, u64)
+#undef LDST
+	STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
+		atomic_add((u32) SRC, (atomic_t *)(unsigned long)
+			   (DST + insn->off));
+		CONT;
+	STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
+		atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
+			     (DST + insn->off));
+		CONT;
+	LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
+		off = IMM;
+load_word:
+		/* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
+		 * only appearing in the programs where ctx ==
+		 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
+		 * == BPF_R6, sk_convert_filter() saves it in BPF_R6,
+		 * internal BPF verifier will check that BPF_R6 ==
+		 * ctx.
+		 *
+		 * BPF_ABS and BPF_IND are wrappers of function calls,
+		 * so they scratch BPF_R1-BPF_R5 registers, preserve
+		 * BPF_R6-BPF_R9, and store return value into BPF_R0.
+		 *
+		 * Implicit input:
+		 *   ctx == skb == BPF_R6 == CTX
+		 *
+		 * Explicit input:
+		 *   SRC == any register
+		 *   IMM == 32-bit immediate
+		 *
+		 * Output:
+		 *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
+		 */
+
+		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
+		if (likely(ptr != NULL)) {
+			BPF_R0 = get_unaligned_be32(ptr);
+			CONT;
+		}
+
+		return 0;
+	LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
+		off = IMM;
+load_half:
+		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
+		if (likely(ptr != NULL)) {
+			BPF_R0 = get_unaligned_be16(ptr);
+			CONT;
+		}
+
+		return 0;
+	LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
+		off = IMM;
+load_byte:
+		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
+		if (likely(ptr != NULL)) {
+			BPF_R0 = *(u8 *)ptr;
+			CONT;
+		}
+
+		return 0;
+	LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
+		off = IMM + SRC;
+		goto load_word;
+	LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
+		off = IMM + SRC;
+		goto load_half;
+	LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
+		off = IMM + SRC;
+		goto load_byte;
+
+	default_label:
+		/* If we ever reach this, we have a bug somewhere. */
+		WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
+		return 0;
+}
+
+void __weak bpf_int_jit_compile(struct sk_filter *prog)
+{
+}
+
+/**
+ *	sk_filter_select_runtime - select execution runtime for BPF program
+ *	@fp: sk_filter populated with internal BPF program
+ *
+ * try to JIT internal BPF program, if JIT is not available select interpreter
+ * BPF program will be executed via SK_RUN_FILTER() macro
+ */
+void sk_filter_select_runtime(struct sk_filter *fp)
+{
+	fp->bpf_func = (void *) __sk_run_filter;
+
+	/* Probe if internal BPF can be JITed */
+	bpf_int_jit_compile(fp);
+}
+EXPORT_SYMBOL_GPL(sk_filter_select_runtime);
+
+/* free internal BPF program */
+void sk_filter_free(struct sk_filter *fp)
+{
+	bpf_jit_free(fp);
+}
+EXPORT_SYMBOL_GPL(sk_filter_free);