def extract_hdr(self, ctx, merged_args):
hdr = merged_args[self.hdr_param_name].p4_val
# apply the local and parent extern type ctxs
for type_name, p4_type in self.extern_ctx.items():
ctx.add_type(type_name, ctx.resolve_type(p4_type))
for type_name, p4_type in self.type_ctx.items():
ctx.add_type(type_name, ctx.resolve_type(p4_type))
# advance the header index if a next field has been accessed
hdr_stack = detect_hdr_stack_next(ctx, hdr)
if hdr_stack:
compare = hdr_stack.locals[
"nextIndex"] >= hdr_stack.locals["size"]
if z3.simplify(compare) == z3.BoolVal(True):
raise ParserException("Index out of bounds!")
# grab the hdr value
hdr_expr = ctx.resolve_expr(hdr)
hdr_expr.activate()
bind_const = z3.Const(f"{self.name}_{self.hdr_param_name}",
hdr_expr.z3_type)
hdr_expr.bind(bind_const)
# advance the stack, if it exists
if hdr_stack:
hdr_stack.locals["lastIndex"] = hdr_stack.locals[
"nextIndex"]
hdr_stack.locals["nextIndex"] += 1
self.call_counter += 1
def eval(self, ctx):
cond = z3.simplify(ctx.resolve_expr(self.cond))
forward_cond_copy = ctx.tmp_forward_cond
then_vars = None
if not z3.is_false(cond):
var_store = ctx.checkpoint()
ctx.tmp_forward_cond = z3.And(forward_cond_copy, cond)
try:
self.then_block.eval(ctx)
except ParserException:
RejectState().eval(ctx)
if not(ctx.has_returned or ctx.get_exited()):
then_vars = ctx.get_attrs()
ctx.set_exited(False)
ctx.has_returned = False
ctx.restore(var_store)
if not z3.is_true(cond):
var_store = ctx.checkpoint()
ctx.tmp_forward_cond = z3.And(forward_cond_copy, z3.Not(cond))
try:
self.else_block.eval(ctx)
except ParserException:
RejectState().eval(ctx)
if ctx.get_exited() or ctx.has_returned:
ctx.restore(var_store)
ctx.set_exited(False)
ctx.has_returned = False
ctx.tmp_forward_cond = forward_cond_copy
if then_vars:
merge_attrs(ctx, cond, then_vars)
def eval(self, ctx):
cond = z3.simplify(
z3.And(z3.Not(z3.Or(*ctx.forward_conds)), ctx.tmp_forward_cond))
if not z3.is_false(cond):
ctx.return_states.append((cond, ctx.copy_attrs()))
ctx.has_returned = True
ctx.forward_conds.append(ctx.tmp_forward_cond)
def eval(self, p4_state):
context = p4_state.current_context()
cond = z3.simplify(p4_state.resolve_expr(self.cond))
forward_cond_copy = context.tmp_forward_cond
then_vars = None
if not cond == z3.BoolVal(False):
var_store, contexts = p4_state.checkpoint()
context.tmp_forward_cond = z3.And(forward_cond_copy, cond)
try:
self.then_block.eval(p4_state)
except ParserException:
RejectState().eval(p4_state)
if not (context.has_returned or p4_state.has_exited):
then_vars = p4_state.get_attrs()
p4_state.has_exited = False
context.has_returned = False
p4_state.restore(var_store, contexts)
if not cond == z3.BoolVal(True):
var_store, contexts = p4_state.checkpoint()
context.tmp_forward_cond = z3.And(forward_cond_copy, z3.Not(cond))
try:
self.else_block.eval(p4_state)
except ParserException:
RejectState().eval(p4_state)
if p4_state.has_exited or context.has_returned:
p4_state.restore(var_store, contexts)
p4_state.has_exited = False
context.has_returned = False
context.tmp_forward_cond = forward_cond_copy
if then_vars:
merge_attrs(p4_state, cond, then_vars)
def eval(self, p4_state):
context = p4_state.current_context()
if self.expr is None:
expr = None
else:
# resolve the expr before restoring the state
expr = p4_state.resolve_expr(self.expr)
if isinstance(context.return_type, z3.BitVecSortRef):
expr = z3_cast(expr, context.return_type)
# we return a complex typed expression list, instantiate
if isinstance(expr, list):
instance = gen_instance(p4_state, "undefined",
context.return_type)
instance.set_list(expr)
expr = instance
cond = z3.simplify(
z3.And(z3.Not(z3.Or(*context.forward_conds)),
context.tmp_forward_cond))
if not cond == z3.BoolVal(False):
context.return_states.append((cond, p4_state.copy_attrs()))
if expr is not None:
context.return_exprs.append((cond, expr))
context.has_returned = True
context.forward_conds.append(context.tmp_forward_cond)
def eval_callable(self, ctx, merged_args, var_buffer):
# tables are a little bit special since they also have attributes
# so what we do here is first initialize the key
hit = self.eval_keys(ctx)
self.locals["hit"] = z3.simplify(hit)
self.locals["miss"] = z3.Not(hit)
# then execute the table as the next expression in the chain
self.eval_table(ctx)
def eval(self, p4_state):
# FIXME: This checkpointing should not be necessary
# Figure out what is going on
var_store, contexts = p4_state.checkpoint()
forward_conds = []
tmp_forward_conds = []
for context in reversed(p4_state.contexts):
context.copy_out(p4_state)
forward_conds.extend(context.forward_conds)
tmp_forward_conds.append(context.tmp_forward_cond)
context = p4_state.current_context()
cond = z3.simplify(
z3.And(z3.Not(z3.Or(*forward_conds)), z3.And(*tmp_forward_conds)))
if not cond == z3.BoolVal(False):
p4_state.exit_states.append((cond, p4_state.get_z3_repr()))
p4_state.has_exited = True
p4_state.restore(var_store, contexts)
context.forward_conds.append(context.tmp_forward_cond)
def eval(self, ctx):
# FIXME: This checkpointing should not be necessary
# Figure out what is going on
var_store = ctx.checkpoint()
forward_conds = []
tmp_forward_conds = []
sub_ctx = ctx
while not isinstance(sub_ctx, StaticContext):
sub_ctx.copy_out(ctx)
forward_conds.extend(sub_ctx.forward_conds)
tmp_forward_conds.append(sub_ctx.tmp_forward_cond)
sub_ctx = sub_ctx.parent_ctx
cond = z3.simplify(
z3.And(z3.Not(z3.Or(*forward_conds)), z3.And(*tmp_forward_conds)))
if not z3.is_false(cond):
ctx.add_exit_state(cond, ctx.get_p4_state().get_members(ctx))
ctx.set_exited(True)
ctx.restore(var_store)
ctx.forward_conds.append(ctx.tmp_forward_cond)
def eval(self, p4_state):
cond = z3.simplify(p4_state.resolve_expr(self.cond))
# handle side effects for function and table calls
if cond == z3.BoolVal(False):
return p4_state.resolve_expr(self.else_val)
if cond == z3.BoolVal(True):
return p4_state.resolve_expr(self.then_val)
var_store, chain_copy = p4_state.checkpoint()
context = p4_state.current_context()
forward_cond_copy = context.tmp_forward_cond
context.tmp_forward_cond = z3.And(forward_cond_copy, cond)
then_expr = p4_state.resolve_expr(self.then_val)
then_vars = p4_state.get_attrs()
p4_state.restore(var_store, chain_copy)
context.tmp_forward_cond = forward_cond_copy
else_expr = p4_state.resolve_expr(self.else_val)
merge_attrs(p4_state, cond, then_vars)
return handle_mux(cond, then_expr, else_expr)
def eval(self, ctx):
if self.expr is None:
expr = None
else:
# resolve the expr before restoring the state
expr = ctx.resolve_expr(self.expr)
if isinstance(ctx.return_type, z3.BitVecSortRef):
expr = z3_cast(expr, ctx.return_type)
# we return a complex typed expression list, instantiate
if isinstance(expr, list):
# name is meaningless here so keep it empty
instance = ctx.gen_instance("", ctx.return_type)
instance.set_list(expr)
expr = instance
cond = z3.simplify(z3.And(z3.Not(z3.Or(*ctx.forward_conds)),
ctx.tmp_forward_cond))
if not z3.is_false(cond):
ctx.return_states.append((cond, ctx.copy_attrs()))
if expr is not None:
ctx.return_exprs.append((cond, expr))
ctx.has_returned = True
ctx.forward_conds.append(ctx.tmp_forward_cond)
