net: filter: Just In Time compiler for x86-64
In order to speedup packet filtering, here is an implementation of a
JIT compiler for x86_64
It is disabled by default, and must be enabled by the admin.
echo 1 >/proc/sys/net/core/bpf_jit_enable
It uses module_alloc() and module_free() to get memory in the 2GB text
kernel range since we call helpers functions from the generated code.
EAX : BPF A accumulator
EBX : BPF X accumulator
RDI : pointer to skb (first argument given to JIT function)
RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
r9d : skb->len - skb->data_len (headlen)
r8 : skb->data
To get a trace of generated code, use :
echo 2 >/proc/sys/net/core/bpf_jit_enable
Example of generated code :
# tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24
flen=18 proglen=147 pass=3 image=ffffffffa00b5000
JIT code: ffffffffa00b5000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 60
JIT code: ffffffffa00b5010: 44 2b 4f 64 4c 8b 87 b8 00 00 00 be 0c 00 00 00
JIT code: ffffffffa00b5020: e8 24 7b f7 e0 3d 00 08 00 00 75 28 be 1a 00 00
JIT code: ffffffffa00b5030: 00 e8 fe 7a f7 e0 24 00 3d 00 14 a8 c0 74 49 be
JIT code: ffffffffa00b5040: 1e 00 00 00 e8 eb 7a f7 e0 24 00 3d 00 14 a8 c0
JIT code: ffffffffa00b5050: 74 36 eb 3b 3d 06 08 00 00 74 07 3d 35 80 00 00
JIT code: ffffffffa00b5060: 75 2d be 1c 00 00 00 e8 c8 7a f7 e0 24 00 3d 00
JIT code: ffffffffa00b5070: 14 a8 c0 74 13 be 26 00 00 00 e8 b5 7a f7 e0 24
JIT code: ffffffffa00b5080: 00 3d 00 14 a8 c0 75 07 b8 ff ff 00 00 eb 02 31
JIT code: ffffffffa00b5090: c0 c9 c3
BPF program is 144 bytes long, so native program is almost same size ;)
(000) ldh [12]
(001) jeq #0x800 jt 2 jf 8
(002) ld [26]
(003) and #0xffffff00
(004) jeq #0xc0a81400 jt 16 jf 5
(005) ld [30]
(006) and #0xffffff00
(007) jeq #0xc0a81400 jt 16 jf 17
(008) jeq #0x806 jt 10 jf 9
(009) jeq #0x8035 jt 10 jf 17
(010) ld [28]
(011) and #0xffffff00
(012) jeq #0xc0a81400 jt 16 jf 13
(013) ld [38]
(014) and #0xffffff00
(015) jeq #0xc0a81400 jt 16 jf 17
(016) ret #65535
(017) ret #0
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 45266b7..4609b85 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -135,6 +135,8 @@
{
atomic_t refcnt;
unsigned int len; /* Number of filter blocks */
+ unsigned int (*bpf_func)(const struct sk_buff *skb,
+ const struct sock_filter *filter);
struct rcu_head rcu;
struct sock_filter insns[0];
};
@@ -153,6 +155,80 @@
extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
extern int sk_detach_filter(struct sock *sk);
extern int sk_chk_filter(struct sock_filter *filter, int flen);
+
+#ifdef CONFIG_BPF_JIT
+extern void bpf_jit_compile(struct sk_filter *fp);
+extern void bpf_jit_free(struct sk_filter *fp);
+#define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
+#else
+static inline void bpf_jit_compile(struct sk_filter *fp)
+{
+}
+static inline void bpf_jit_free(struct sk_filter *fp)
+{
+}
+#define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
+#endif
+
+enum {
+ BPF_S_RET_K = 1,
+ BPF_S_RET_A,
+ BPF_S_ALU_ADD_K,
+ BPF_S_ALU_ADD_X,
+ BPF_S_ALU_SUB_K,
+ BPF_S_ALU_SUB_X,
+ BPF_S_ALU_MUL_K,
+ BPF_S_ALU_MUL_X,
+ BPF_S_ALU_DIV_X,
+ BPF_S_ALU_AND_K,
+ BPF_S_ALU_AND_X,
+ BPF_S_ALU_OR_K,
+ BPF_S_ALU_OR_X,
+ BPF_S_ALU_LSH_K,
+ BPF_S_ALU_LSH_X,
+ BPF_S_ALU_RSH_K,
+ BPF_S_ALU_RSH_X,
+ BPF_S_ALU_NEG,
+ BPF_S_LD_W_ABS,
+ BPF_S_LD_H_ABS,
+ BPF_S_LD_B_ABS,
+ BPF_S_LD_W_LEN,
+ BPF_S_LD_W_IND,
+ BPF_S_LD_H_IND,
+ BPF_S_LD_B_IND,
+ BPF_S_LD_IMM,
+ BPF_S_LDX_W_LEN,
+ BPF_S_LDX_B_MSH,
+ BPF_S_LDX_IMM,
+ BPF_S_MISC_TAX,
+ BPF_S_MISC_TXA,
+ BPF_S_ALU_DIV_K,
+ BPF_S_LD_MEM,
+ BPF_S_LDX_MEM,
+ BPF_S_ST,
+ BPF_S_STX,
+ BPF_S_JMP_JA,
+ BPF_S_JMP_JEQ_K,
+ BPF_S_JMP_JEQ_X,
+ BPF_S_JMP_JGE_K,
+ BPF_S_JMP_JGE_X,
+ BPF_S_JMP_JGT_K,
+ BPF_S_JMP_JGT_X,
+ BPF_S_JMP_JSET_K,
+ BPF_S_JMP_JSET_X,
+ /* Ancillary data */
+ BPF_S_ANC_PROTOCOL,
+ BPF_S_ANC_PKTTYPE,
+ BPF_S_ANC_IFINDEX,
+ BPF_S_ANC_NLATTR,
+ BPF_S_ANC_NLATTR_NEST,
+ BPF_S_ANC_MARK,
+ BPF_S_ANC_QUEUE,
+ BPF_S_ANC_HATYPE,
+ BPF_S_ANC_RXHASH,
+ BPF_S_ANC_CPU,
+};
+
#endif /* __KERNEL__ */
#endif /* __LINUX_FILTER_H__ */
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cb8178ab..364bcf2 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2514,6 +2514,7 @@
extern int netdev_max_backlog;
extern int netdev_tstamp_prequeue;
extern int weight_p;
+extern int bpf_jit_enable;
extern int netdev_set_master(struct net_device *dev, struct net_device *master);
extern int netdev_set_bond_master(struct net_device *dev,
struct net_device *master);
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d0ae90a..79aafbb 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -391,8 +391,8 @@
__u32 rxhash;
+ __u16 queue_mapping;
kmemcheck_bitfield_begin(flags2);
- __u16 queue_mapping:16;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
__u8 ndisc_nodetype:2;
#endif