Adjust the expression size to 1B so cmp expression value is correct.
Without this, the rule 'fib saddr . iif check exists' generates
following byte code on BE:
| [ fib saddr . iif oif present => reg 1 ]
| [ cmp eq reg 1 0x00000001 ]
Though with NFTA_FIB_F_PRESENT flag set, nft_fib.ko writes to the first
byte of reg 1 only (using nft_reg_store8()). With this patch in place,
byte code is correct:
| [ fib saddr . iif oif present => reg 1 ]
| [ cmp eq reg 1 0x01000000 ]
Fixes: f686a17eafa0b ("fib: Support existence check")
Cc: Yi Chen <yiche@xxxxxxxxxx>
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
src/evaluate.c | 1 +
src/fib.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/src/evaluate.c b/src/evaluate.c
index 8cecbe09de01c..6a1aa4963bceb 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -3002,6 +3002,7 @@ static int expr_evaluate_fib(struct eval_ctx *ctx, struct expr **exprp)
if (expr->flags & EXPR_F_BOOLEAN) {
expr->fib.flags |= NFTA_FIB_F_PRESENT;
datatype_set(expr, &boolean_type);
+ expr->len = BITS_PER_BYTE;
}
return expr_evaluate_primary(ctx, exprp);
}
diff --git a/src/fib.c b/src/fib.c
index 5383613292a5e..4db7cd2bbc9c3 100644
--- a/src/fib.c
+++ b/src/fib.c
@@ -198,8 +198,10 @@ struct expr *fib_expr_alloc(const struct location *loc,
BUG("Unknown result %d\n", result);
}
- if (flags & NFTA_FIB_F_PRESENT)
+ if (flags & NFTA_FIB_F_PRESENT) {
type = &boolean_type;
+ len = BITS_PER_BYTE;
+ }
expr = expr_alloc(loc, EXPR_FIB, type,
BYTEORDER_HOST_ENDIAN, len);
--
2.51.0
