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Merge branch 'bpf-push-pop-helpers' 

Alexei Starovoitov says:

====================
bpf: introduce bpf_skb_vlan_push/pop() helpers

Let TC+eBPF programs call skb_vlan_push/pop via helpers.

v1->v2:
- reworded commit log to better explain correctness of re-caching
  and fixed comparison of mixed endiannes (suggested by Eric)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2015-07-20 20:52:32 -07:00
parent f3120acc78 4d9c5c53ac
commit 500322ec41
8 changed files with 197 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/s390/net/bpf_jit_comp.c
View File

@ -973,6 +973,10 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
*/
const u64 func = (u64)__bpf_call_base + imm;
if (bpf_helper_changes_skb_data((void *)func))
/* TODO reload skb->data, hlen */
return -1;
REG_SET_SEEN(BPF_REG_5);
jit->seen |= SEEN_FUNC;
/* lg %w1,<d(imm)>(%l) */

80
arch/x86/net/bpf_jit_comp.c
View File

@ -315,6 +315,26 @@ static void emit_bpf_tail_call(u8 **pprog)
*pprog = prog;
}
static void emit_load_skb_data_hlen(u8 **pprog)
{
u8 *prog = *pprog;
int cnt = 0;
/* r9d = skb->len - skb->data_len (headlen)
* r10 = skb->data
*/
/* mov %r9d, off32(%rdi) */
EMIT3_off32(0x44, 0x8b, 0x8f, offsetof(struct sk_buff, len));
/* sub %r9d, off32(%rdi) */
EMIT3_off32(0x44, 0x2b, 0x8f, offsetof(struct sk_buff, data_len));
/* mov %r10, off32(%rdi) */
EMIT3_off32(0x4c, 0x8b, 0x97, offsetof(struct sk_buff, data));
*pprog = prog;
}
static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
int oldproglen, struct jit_context *ctx)
{
@ -329,36 +349,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
emit_prologue(&prog);
if (seen_ld_abs) {
/* r9d : skb->len - skb->data_len (headlen)
* r10 : skb->data
*/
if (is_imm8(offsetof(struct sk_buff, len)))
/* mov %r9d, off8(%rdi) */
EMIT4(0x44, 0x8b, 0x4f,
offsetof(struct sk_buff, len));
else
/* mov %r9d, off32(%rdi) */
EMIT3_off32(0x44, 0x8b, 0x8f,
offsetof(struct sk_buff, len));
if (is_imm8(offsetof(struct sk_buff, data_len)))
/* sub %r9d, off8(%rdi) */
EMIT4(0x44, 0x2b, 0x4f,
offsetof(struct sk_buff, data_len));
else
EMIT3_off32(0x44, 0x2b, 0x8f,
offsetof(struct sk_buff, data_len));
if (is_imm8(offsetof(struct sk_buff, data)))
/* mov %r10, off8(%rdi) */
EMIT4(0x4c, 0x8b, 0x57,
offsetof(struct sk_buff, data));
else
/* mov %r10, off32(%rdi) */
EMIT3_off32(0x4c, 0x8b, 0x97,
offsetof(struct sk_buff, data));
}
if (seen_ld_abs)
emit_load_skb_data_hlen(&prog);
for (i = 0; i < insn_cnt; i++, insn++) {
const s32 imm32 = insn->imm;
@ -367,6 +359,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
u8 b1 = 0, b2 = 0, b3 = 0;
s64 jmp_offset;
u8 jmp_cond;
bool reload_skb_data;
int ilen;
u8 *func;
@ -818,12 +811,18 @@ xadd: if (is_imm8(insn->off))
func = (u8 *) __bpf_call_base + imm32;
jmp_offset = func - (image + addrs[i]);
if (seen_ld_abs) {
EMIT2(0x41, 0x52); /* push %r10 */
EMIT2(0x41, 0x51); /* push %r9 */
/* need to adjust jmp offset, since
* pop %r9, pop %r10 take 4 bytes after call insn
*/
jmp_offset += 4;
reload_skb_data = bpf_helper_changes_skb_data(func);
if (reload_skb_data) {
EMIT1(0x57); /* push %rdi */
jmp_offset += 22; /* pop, mov, sub, mov */
} else {
EMIT2(0x41, 0x52); /* push %r10 */
EMIT2(0x41, 0x51); /* push %r9 */
/* need to adjust jmp offset, since
* pop %r9, pop %r10 take 4 bytes after call insn
*/
jmp_offset += 4;
}
}
if (!imm32 || !is_simm32(jmp_offset)) {
pr_err("unsupported bpf func %d addr %p image %p\n",
@ -832,8 +831,13 @@ xadd: if (is_imm8(insn->off))
}
EMIT1_off32(0xE8, jmp_offset);
if (seen_ld_abs) {
EMIT2(0x41, 0x59); /* pop %r9 */
EMIT2(0x41, 0x5A); /* pop %r10 */
if (reload_skb_data) {
EMIT1(0x5F); /* pop %rdi */
emit_load_skb_data_hlen(&prog);
} else {
EMIT2(0x41, 0x59); /* pop %r9 */
EMIT2(0x41, 0x5A); /* pop %r10 */
}
}
break;

2
include/linux/bpf.h
View File

@ -192,5 +192,7 @@ extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
extern const struct bpf_func_proto bpf_get_current_comm_proto;
extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
#endif /* _LINUX_BPF_H */

1
include/linux/filter.h
View File

@ -411,6 +411,7 @@ void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
void bpf_int_jit_compile(struct bpf_prog *fp);
bool bpf_helper_changes_skb_data(void *func);
#ifdef CONFIG_BPF_JIT
typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);

2
include/uapi/linux/bpf.h
View File

@ -256,6 +256,8 @@ enum bpf_func_id {
* Return: classid if != 0
*/
BPF_FUNC_get_cgroup_classid,
BPF_FUNC_skb_vlan_push, /* bpf_skb_vlan_push(skb, vlan_proto, vlan_tci) */
BPF_FUNC_skb_vlan_pop, /* bpf_skb_vlan_pop(skb) */
__BPF_FUNC_MAX_ID,
};

1
kernel/bpf/core.c
View File

@ -177,6 +177,7 @@ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
return 0;
}
EXPORT_SYMBOL_GPL(__bpf_call_base);
/**
* __bpf_prog_run - run eBPF program on a given context

98
lib/test_bpf.c
View File

@ -18,6 +18,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
@ -355,6 +356,81 @@ static int bpf_fill_ja(struct bpf_test *self)
return __bpf_fill_ja(self, 12, 9);
}
static int bpf_fill_ld_abs_get_processor_id(struct bpf_test *self)
{
unsigned int len = BPF_MAXINSNS;
struct sock_filter *insn;
int i;
insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);
if (!insn)
return -ENOMEM;
for (i = 0; i < len - 1; i += 2) {
insn[i] = __BPF_STMT(BPF_LD | BPF_B | BPF_ABS, 0);
insn[i + 1] = __BPF_STMT(BPF_LD | BPF_W | BPF_ABS,
SKF_AD_OFF + SKF_AD_CPU);
}
insn[len - 1] = __BPF_STMT(BPF_RET | BPF_K, 0xbee);
self->u.ptr.insns = insn;
self->u.ptr.len = len;
return 0;
}
#define PUSH_CNT 68
/* test: {skb->data[0], vlan_push} x 68 + {skb->data[0], vlan_pop} x 68 */
static int bpf_fill_ld_abs_vlan_push_pop(struct bpf_test *self)
{
unsigned int len = BPF_MAXINSNS;
struct bpf_insn *insn;
int i = 0, j, k = 0;
insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);
if (!insn)
return -ENOMEM;
insn[i++] = BPF_MOV64_REG(R6, R1);
loop:
for (j = 0; j < PUSH_CNT; j++) {
insn[i++] = BPF_LD_ABS(BPF_B, 0);
insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0x34, len - i - 2);
i++;
insn[i++] = BPF_MOV64_REG(R1, R6);
insn[i++] = BPF_MOV64_IMM(R2, 1);
insn[i++] = BPF_MOV64_IMM(R3, 2);
insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
bpf_skb_vlan_push_proto.func - __bpf_call_base);
insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0, len - i - 2);
i++;
}
for (j = 0; j < PUSH_CNT; j++) {
insn[i++] = BPF_LD_ABS(BPF_B, 0);
insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0x34, len - i - 2);
i++;
insn[i++] = BPF_MOV64_REG(R1, R6);
insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
bpf_skb_vlan_pop_proto.func - __bpf_call_base);
insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0, len - i - 2);
i++;
}
if (++k < 5)
goto loop;
for (; i < len - 1; i++)
insn[i] = BPF_ALU32_IMM(BPF_MOV, R0, 0xbef);
insn[len - 1] = BPF_EXIT_INSN();
self->u.ptr.insns = insn;
self->u.ptr.len = len;
return 0;
}
static struct bpf_test tests[] = {
{
"TAX",
@ -4398,6 +4474,22 @@ static struct bpf_test tests[] = {
{ { 0, 0xababcbac } },
.fill_helper = bpf_fill_maxinsns11,
},
{
"BPF_MAXINSNS: ld_abs+get_processor_id",
{ },
CLASSIC,
{ },
{ { 1, 0xbee } },
.fill_helper = bpf_fill_ld_abs_get_processor_id,
},
{
"BPF_MAXINSNS: ld_abs+vlan_push/pop",
{ },
INTERNAL,
{ 0x34 },
{ { 1, 0xbef } },
.fill_helper = bpf_fill_ld_abs_vlan_push_pop,
},
};
static struct net_device dev;
@ -4551,14 +4643,14 @@ static int __run_one(const struct bpf_prog *fp, const void *data,
u64 start, finish;
int ret = 0, i;
start = ktime_to_us(ktime_get());
start = ktime_get_ns();
for (i = 0; i < runs; i++)
ret = BPF_PROG_RUN(fp, data);
finish = ktime_to_us(ktime_get());
finish = ktime_get_ns();
*duration = (finish - start) * 1000ULL;
*duration = finish - start;
do_div(*duration, runs);
return ret;

50
net/core/filter.c
View File

@ -1437,6 +1437,52 @@ static const struct bpf_func_proto bpf_get_cgroup_classid_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *) (long) r1;
__be16 vlan_proto = (__force __be16) r2;
if (unlikely(vlan_proto != htons(ETH_P_8021Q) &&
vlan_proto != htons(ETH_P_8021AD)))
vlan_proto = htons(ETH_P_8021Q);
return skb_vlan_push(skb, vlan_proto, vlan_tci);
}
const struct bpf_func_proto bpf_skb_vlan_push_proto = {
.func = bpf_skb_vlan_push,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
};
EXPORT_SYMBOL_GPL(bpf_skb_vlan_push_proto);
static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *) (long) r1;
return skb_vlan_pop(skb);
}
const struct bpf_func_proto bpf_skb_vlan_pop_proto = {
.func = bpf_skb_vlan_pop,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
};
EXPORT_SYMBOL_GPL(bpf_skb_vlan_pop_proto);
bool bpf_helper_changes_skb_data(void *func)
{
if (func == bpf_skb_vlan_push)
return true;
if (func == bpf_skb_vlan_pop)
return true;
return false;
}
static const struct bpf_func_proto *
sk_filter_func_proto(enum bpf_func_id func_id)
{
@ -1476,6 +1522,10 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
return &bpf_clone_redirect_proto;
case BPF_FUNC_get_cgroup_classid:
return &bpf_get_cgroup_classid_proto;
case BPF_FUNC_skb_vlan_push:
return &bpf_skb_vlan_push_proto;
case BPF_FUNC_skb_vlan_pop:
return &bpf_skb_vlan_pop_proto;
default:
return sk_filter_func_proto(func_id);
}