Write a bunch of module documentation.

This commit adds or improves the module-level documenation for:

  buffers.c circuitstats.c command.c connection_edge.c control.c
  cpuworker.c crypto_curve25519.c crypto_curve25519.h
  crypto_ed25519.c crypto_format.c dircollate.c dirserv.c dns.c
  dns_structs.h fp_pair.c geoip.c hibernate.c keypin.c ntmain.c
  onion.c onion_fast.c onion_ntor.c onion_tap.c periodic.c
  protover.c protover.h reasons.c rephist.c replaycache.c
  routerlist.c routerparse.c routerset.c statefile.c status.c
  tor_main.c workqueue.c

In particular, I've tried to explain (for each documented module)
what each module does, what's in it, what the big idea is, why it
belongs in Tor, and who calls it.  In a few cases, I've added TODO
notes about refactoring opportunities.

I've also renamed an argument, and fixed a few DOCDOC comments.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/common/crypto_curve25519.h b/src/common/crypto_curve25519.h
index 547e393567..4011820949 100644
--- a/src/common/crypto_curve25519.h
+++ b/src/common/crypto_curve25519.h
@@ -14,12 +14,20 @@
 /** Length of the result of a curve25519 handshake. */
 #define CURVE25519_OUTPUT_LEN 32
 
-/** Wrapper type for a curve25519 public key */
+/** Wrapper type for a curve25519 public key.
+ *
+ *  (We define a separate type for these to make it less likely that we'll
+ *  mistake them for secret keys.)
+ * */
 typedef struct curve25519_public_key_t {
   uint8_t public_key[CURVE25519_PUBKEY_LEN];
 } curve25519_public_key_t;
 
-/** Wrapper type for a curve25519 secret key */
+/** Wrapper type for a curve25519 secret key
+ *
+ * (We define a separate type for these to make it less likely that we'll
+ * mistake them for public keys.)
+ **/
 typedef struct curve25519_secret_key_t {
   uint8_t secret_key[CURVE25519_SECKEY_LEN];
 } curve25519_secret_key_t;