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authorEric Dumazet <edumazet@google.com>2012-09-07 22:03:35 +0000
committerDavid S. Miller <davem@davemloft.net>2012-09-10 15:44:56 -0400
commitb6069a95706ca5738be3f5d90fd286cbd13ac695 (patch)
tree8d3d2f11385265b3a0a7d03f07d98752b694ed14 /net/core
parentc6bb8136c95ce16545f8c4028e958c0ee6c86f23 (diff)
downloadop-kernel-dev-b6069a95706ca5738be3f5d90fd286cbd13ac695.zip
op-kernel-dev-b6069a95706ca5738be3f5d90fd286cbd13ac695.tar.gz
filter: add MOD operation
Add a new ALU opcode, to compute a modulus. Commit ffe06c17afbbb used an ancillary to implement XOR_X, but here we reserve one of the available ALU opcode to implement both MOD_X and MOD_K Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: George Bakos <gbakos@alpinista.org> Cc: Jay Schulist <jschlst@samba.org> Cc: Jiri Pirko <jpirko@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 907efd2..fbe3a8d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -167,6 +167,14 @@ unsigned int sk_run_filter(const struct sk_buff *skb,
case BPF_S_ALU_DIV_K:
A = reciprocal_divide(A, K);
continue;
+ case BPF_S_ALU_MOD_X:
+ if (X == 0)
+ return 0;
+ A %= X;
+ continue;
+ case BPF_S_ALU_MOD_K:
+ A %= K;
+ continue;
case BPF_S_ALU_AND_X:
A &= X;
continue;
@@ -469,6 +477,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
[BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K,
[BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X,
[BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X,
+ [BPF_ALU|BPF_MOD|BPF_K] = BPF_S_ALU_MOD_K,
+ [BPF_ALU|BPF_MOD|BPF_X] = BPF_S_ALU_MOD_X,
[BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K,
[BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X,
[BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K,
@@ -531,6 +541,11 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
return -EINVAL;
ftest->k = reciprocal_value(ftest->k);
break;
+ case BPF_S_ALU_MOD_K:
+ /* check for division by zero */
+ if (ftest->k == 0)
+ return -EINVAL;
+ break;
case BPF_S_LD_MEM:
case BPF_S_LDX_MEM:
case BPF_S_ST:
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