- Move test-only cpath_get_n_hops() to crypt_path.c.
- Move onion_next_hop_in_cpath() and rename to cpath_get_next_non_open_hop().
The latter function was directly accessing cpath->state, and it's a first step
at hiding ->state.
Some of these functions are now public and cpath-specific so their name should
signify the fact they are part of the cpath module:
assert_cpath_layer_ok -> cpath_assert_layer_ok
assert_cpath_ok -> cpath_assert_ok
onion_append_hop -> cpath_append_hop
circuit_init_cpath_crypto -> cpath_init_circuit_crypto
circuit_free_cpath_node -> cpath_free
onion_append_to_cpath -> cpath_extend_linked_list
Now that we are using a constructor we should be more careful that we are
always using the constructor to initialize crypt_path_t, so make sure that
->private is initialized.
We are using an opaque pointer so the structure needs to be allocated on the
heap. This means we now need a constructor for crypt_path_t.
Also modify all places initializing a crypt_path_t to use the constructor.
For various reasons, this was a nontrivial movement. There are
several places in the code where we do something like "update the
flags on this routerstatus or node if we're an authority", and at
least one where we pretended to be an authority when we weren't.
I don't believe any of these represent a real timing vulnerability
(remote timing against memcmp() on a modern CPU is not easy), but
these are the ones where I believe we should be more careful.
For memeq and friends, "tor_" indicates constant-time and "fast_"
indicates optimized. I'm fine with leaving the constant-time
"safe_mem_is_zero" with its current name, but the "tor_" prefix on
the current optimized version is misleading.
Also, make the tor_digest*_is_zero() uniformly constant-time, and
add a fast_digest*_is_zero() version to use as needed.
A later commit in this branch will fix all the users of
tor_mem_is_zero().
Closes ticket 30309.
Manually fix up some reply-generating code that the Coccinelle scripts
won't match. Some more complicated ones remain -- these are mostly
ones that accumulate data to send, and then call connection_buf_add()
or connection_write_str_to_buf() directly.
