diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/noise.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/src/noise.c b/src/noise.c index 070a0d8..b24b483 100644 --- a/src/noise.c +++ b/src/noise.c @@ -120,15 +120,30 @@ static void add_new_keypair(struct noise_keypairs *keypairs, struct noise_keypai next_keypair = rcu_dereference_protected(keypairs->next_keypair, lockdep_is_held(&keypairs->keypair_update_lock)); current_keypair = rcu_dereference_protected(keypairs->current_keypair, lockdep_is_held(&keypairs->keypair_update_lock)); if (new_keypair->i_am_the_initiator) { + /* If we're the initiator, it means we've sent a handshake, and received + * a confirmation response, which means this new keypair can now be used. */ if (next_keypair) { + /* If there already was a next keypair pending, we demote it to be + * the previous keypair, and free the existing current. + * TODO: note that this means KCI can result in this transition. It + * would perhaps be more sound to always just get rid of the unused + * next keypair instead of putting it in the previous slot, but this + * might be a bit less robust. Something to think about and decide on. */ rcu_assign_pointer(keypairs->next_keypair, NULL); rcu_assign_pointer(keypairs->previous_keypair, next_keypair); noise_keypair_put(current_keypair); - } else + } else /* If there wasn't an existing next keypair, we replace the + * previous with the current one. */ rcu_assign_pointer(keypairs->previous_keypair, current_keypair); + /* At this point we can get rid of the old previous keypair, and set up + * the new keypair. */ noise_keypair_put(previous_keypair); rcu_assign_pointer(keypairs->current_keypair, new_keypair); } else { + /* If we're the responder, it means we can't use the new keypair until + * we receive confirmation via the first data packet, so we get rid of + * the existing previous one, the possibly existing next one, and slide + * in the new next one. */ rcu_assign_pointer(keypairs->next_keypair, new_keypair); noise_keypair_put(next_keypair); rcu_assign_pointer(keypairs->previous_keypair, NULL); @@ -147,6 +162,9 @@ bool noise_received_with_keypair(struct noise_keypairs *keypairs, struct noise_k rcu_read_lock(); if (unlikely(received_keypair == rcu_dereference(keypairs->next_keypair))) { ret = true; + /* When we've finally received the confirmation, we slide the next + * into the current, the current into the previous, and get rid of + * the old previous. */ old_keypair = rcu_dereference(keypairs->previous_keypair); rcu_assign_pointer(keypairs->previous_keypair, rcu_dereference(keypairs->current_keypair)); noise_keypair_put(old_keypair); |