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Message-Id: <ce1ddcbf8c0effcfa561b224630e3645504a6ad4.1356960070.git.dborkman@redhat.com>
Date: Mon, 31 Dec 2012 14:59:45 +0100
From: Daniel Borkmann <dborkman@...hat.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org
Subject: [PATCH net-next 5/8] net: bpf: add neq jump operations to bpf machine
This patch adds jump operations for neq (!=) that compare A
with K resp. X in order to facilitate filter programming with
conditional jumps, since currently only eq (==) is present in
the BPF machine. For user-space filter programming / compilers,
it might be good to also have this complementary operation.
They don't need to be as ancillary, since they fit into the
instruction encoding directly. Follow-up BPF JIT patches are
welcomed.
Signed-off-by: Daniel Borkmann <dborkman@...hat.com>
---
include/linux/filter.h | 2 ++
include/uapi/linux/filter.h | 1 +
net/core/filter.c | 14 ++++++++++++++
3 files changed, 17 insertions(+)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 36630bc..256c01f 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -105,6 +105,8 @@ enum {
BPF_S_JMP_JA,
BPF_S_JMP_JEQ_K,
BPF_S_JMP_JEQ_X,
+ BPF_S_JMP_JNEQ_K,
+ BPF_S_JMP_JNEQ_X,
BPF_S_JMP_JGE_K,
BPF_S_JMP_JGE_X,
BPF_S_JMP_JGT_K,
diff --git a/include/uapi/linux/filter.h b/include/uapi/linux/filter.h
index 3ebcc2e..d909a6f 100644
--- a/include/uapi/linux/filter.h
+++ b/include/uapi/linux/filter.h
@@ -80,6 +80,7 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
#define BPF_JSET 0x40
#define BPF_JLT 0x50
#define BPF_JLE 0x60
+#define BPF_JNEQ 0x70
#define BPF_SRC(code) ((code) & 0x08)
#define BPF_K 0x00
diff --git a/net/core/filter.c b/net/core/filter.c
index 2122eba..b360fb3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -228,6 +228,9 @@ unsigned int sk_run_filter(const struct sk_buff *skb,
case BPF_S_JMP_JEQ_K:
fentry += (A == K) ? fentry->jt : fentry->jf;
continue;
+ case BPF_S_JMP_JNEQ_K:
+ fentry += (A != K) ? fentry->jt : fentry->jf;
+ continue;
case BPF_S_JMP_JSET_K:
fentry += (A & K) ? fentry->jt : fentry->jf;
continue;
@@ -246,6 +249,9 @@ unsigned int sk_run_filter(const struct sk_buff *skb,
case BPF_S_JMP_JEQ_X:
fentry += (A == X) ? fentry->jt : fentry->jf;
continue;
+ case BPF_S_JMP_JNEQ_X:
+ fentry += (A != X) ? fentry->jt : fentry->jf;
+ continue;
case BPF_S_JMP_JSET_X:
fentry += (A & X) ? fentry->jt : fentry->jf;
continue;
@@ -454,6 +460,8 @@ static int check_load_and_stores(struct sock_filter *filter, int flen)
break;
case BPF_S_JMP_JEQ_K:
case BPF_S_JMP_JEQ_X:
+ case BPF_S_JMP_JNEQ_K:
+ case BPF_S_JMP_JNEQ_X:
case BPF_S_JMP_JGE_K:
case BPF_S_JMP_JGE_X:
case BPF_S_JMP_JGT_K:
@@ -540,6 +548,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
[BPF_JMP|BPF_JA] = BPF_S_JMP_JA,
[BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K,
[BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X,
+ [BPF_JMP|BPF_JNEQ|BPF_K] = BPF_S_JMP_JNEQ_K,
+ [BPF_JMP|BPF_JNEQ|BPF_X] = BPF_S_JMP_JNEQ_X,
[BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K,
[BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X,
[BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K,
@@ -599,6 +609,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
break;
case BPF_S_JMP_JEQ_K:
case BPF_S_JMP_JEQ_X:
+ case BPF_S_JMP_JNEQ_K:
+ case BPF_S_JMP_JNEQ_X:
case BPF_S_JMP_JGE_K:
case BPF_S_JMP_JGE_X:
case BPF_S_JMP_JGT_K:
@@ -852,6 +864,8 @@ static void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
[BPF_S_JMP_JA] = BPF_JMP|BPF_JA,
[BPF_S_JMP_JEQ_K] = BPF_JMP|BPF_JEQ|BPF_K,
[BPF_S_JMP_JEQ_X] = BPF_JMP|BPF_JEQ|BPF_X,
+ [BPF_S_JMP_JNEQ_K] = BPF_JMP|BPF_JNEQ|BPF_K,
+ [BPF_S_JMP_JNEQ_X] = BPF_JMP|BPF_JNEQ|BPF_X,
[BPF_S_JMP_JGE_K] = BPF_JMP|BPF_JGE|BPF_K,
[BPF_S_JMP_JGE_X] = BPF_JMP|BPF_JGE|BPF_X,
[BPF_S_JMP_JGT_K] = BPF_JMP|BPF_JGT|BPF_K,
--
1.7.11.7
--
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