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-rw-r--r--src/evaluate.c80
1 files changed, 76 insertions, 4 deletions
diff --git a/src/evaluate.c b/src/evaluate.c
index 7962e9e4..f2b6dd1e 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1613,13 +1613,85 @@ static int stmt_evaluate_verdict(struct eval_ctx *ctx, struct stmt *stmt)
static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt)
{
+ struct expr *binop, *mask, *and, *payload_bytes;
+ unsigned int masklen, extra_len = 0;
+ unsigned int payload_byte_size;
+ uint8_t shift_imm, data[NFT_REG_SIZE];
+ struct expr *payload;
+ mpz_t bitmask, ff;
+
if (__expr_evaluate_payload(ctx, stmt->payload.expr) < 0)
return -1;
- return stmt_evaluate_arg(ctx, stmt,
- stmt->payload.expr->dtype,
- stmt->payload.expr->len,
- &stmt->payload.val);
+ payload = stmt->payload.expr;
+ if (stmt_evaluate_arg(ctx, stmt, payload->dtype, payload->len,
+ &stmt->payload.val) < 0)
+ return -1;
+
+ if (!payload_needs_adjustment(payload))
+ return 0;
+
+ shift_imm = expr_offset_shift(payload, payload->payload.offset,
+ &extra_len);
+ if (shift_imm) {
+ struct expr *off;
+
+ off = constant_expr_alloc(&payload->location,
+ expr_basetype(payload),
+ BYTEORDER_HOST_ENDIAN,
+ sizeof(shift_imm), &shift_imm);
+
+ binop = binop_expr_alloc(&payload->location, OP_LSHIFT,
+ stmt->payload.val, off);
+ binop->dtype = payload->dtype;
+ binop->byteorder = payload->byteorder;
+
+ stmt->payload.val = binop;
+ }
+
+ payload_byte_size = round_up(payload->len, BITS_PER_BYTE) / BITS_PER_BYTE;
+ payload_byte_size += (extra_len / BITS_PER_BYTE);
+ masklen = payload_byte_size * BITS_PER_BYTE;
+ mpz_init_bitmask(ff, masklen);
+
+ mpz_init2(bitmask, masklen);
+ mpz_bitmask(bitmask, payload->len);
+ mpz_lshift_ui(bitmask, shift_imm);
+
+ mpz_xor(bitmask, ff, bitmask);
+ mpz_clear(ff);
+
+ assert(sizeof(data) * BITS_PER_BYTE >= masklen);
+ mpz_export_data(data, bitmask, BYTEORDER_HOST_ENDIAN, masklen);
+ mask = constant_expr_alloc(&payload->location, expr_basetype(payload),
+ BYTEORDER_HOST_ENDIAN, masklen, data);
+
+ payload_bytes = payload_expr_alloc(&payload->location, NULL, 0);
+ payload_init_raw(payload_bytes, payload->payload.base,
+ (payload->payload.offset / BITS_PER_BYTE) * BITS_PER_BYTE,
+ payload_byte_size * BITS_PER_BYTE);
+
+ payload_bytes->payload.desc = payload->payload.desc;
+ payload_bytes->dtype = &integer_type;
+ payload_bytes->byteorder = payload->byteorder;
+
+ payload->len = payload_bytes->len;
+ payload->payload.offset = payload_bytes->payload.offset;
+
+ and = binop_expr_alloc(&payload->location, OP_AND, payload_bytes, mask);
+
+ and->dtype = payload_bytes->dtype;
+ and->byteorder = payload_bytes->byteorder;
+ and->len = payload_bytes->len;
+
+ binop = binop_expr_alloc(&payload->location, OP_XOR, and,
+ stmt->payload.val);
+ binop->dtype = payload->dtype;
+ binop->byteorder = payload->byteorder;
+ binop->len = mask->len;
+ stmt->payload.val = binop;
+
+ return expr_evaluate(ctx, &stmt->payload.val);
}
static int stmt_evaluate_flow(struct eval_ctx *ctx, struct stmt *stmt)