diff options
| author | Eric Dumazet <edumazet@google.com> | 2012-09-07 22:03:35 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-09-10 15:44:56 -0400 |
| commit | b6069a95706ca5738be3f5d90fd286cbd13ac695 (patch) | |
| tree | 8d3d2f11385265b3a0a7d03f07d98752b694ed14 | |
| parent | c6bb8136c95ce16545f8c4028e958c0ee6c86f23 (diff) | |
| download | linux-b6069a95706ca5738be3f5d90fd286cbd13ac695.tar.bz2 | |
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>
| -rw-r--r-- | include/linux/filter.h | 4 | ||||
| -rw-r--r-- | net/core/filter.c | 15 |
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index 82b01357af8b..3cf5fd561d86 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -74,6 +74,8 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ #define BPF_LSH 0x60 #define BPF_RSH 0x70 #define BPF_NEG 0x80 +#define BPF_MOD 0x90 + #define BPF_JA 0x00 #define BPF_JEQ 0x10 #define BPF_JGT 0x20 @@ -196,6 +198,8 @@ enum { BPF_S_ALU_MUL_K, BPF_S_ALU_MUL_X, BPF_S_ALU_DIV_X, + BPF_S_ALU_MOD_K, + BPF_S_ALU_MOD_X, BPF_S_ALU_AND_K, BPF_S_ALU_AND_X, BPF_S_ALU_OR_K, diff --git a/net/core/filter.c b/net/core/filter.c index 907efd27ec77..fbe3a8d12570 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: |