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 Signed-off-by: Phil Sutter --- 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