make it nicer

doc/iwp_v0.txt

@@ -78,18 +78,19 @@ dropping if it does not match.
 
 2) session start
 
-Alice uses the token from bob to start the wire session
+Alice uses the token from the previous message to start the wire session
 
 32 bytes hmac, h
 32 bytes nounce, n
 32 bytes ciphertext, x
 variadic byttes padding, w2
 
-T = HS(token + n)
 w2 = "[insert variable length random padding here]"
+e_K = TKE(a.k, b.k, n)
+x = SE(e_K, token, n[0:24])
+h = MDS(n + x + w2, e_K)
+T = HS(token + n)
 K = TKE(a.k, b.k, T)
-x = SE(K, token, n[0:24])
-h = MDS(n + x + w2, K)
 
 Alice transmits ( h + n + x + w2 )
 Bob recieves ( h + n + x + w2) and verifies that h == MDS(n + x, k) silently

include/llarp/crypto_async.h

@@ -98,6 +98,8 @@ struct iwp_async_session_start
   uint8_t * nonce;
   uint8_t * token;
   uint8_t * sessionkey;
+  uint8_t * secretkey;
+  uint8_t * remote_pubkey;
   iwp_session_start_hook hook;
 };
 

llarp/crypto_async.cpp

@@ -11,30 +11,33 @@ struct llarp_async_iwp
   struct llarp_threadpool * worker;
 };
 
-void iwp_inform_keygen(void * user)
+namespace iwp
+{
+
+void inform_keygen(void * user)
 {
   iwp_async_keygen * keygen = static_cast<iwp_async_keygen *>(user);
   keygen->hook(keygen);
 }
 
-void iwp_do_keygen(void * user)
+void keygen(void * user)
 {
   iwp_async_keygen * keygen = static_cast<iwp_async_keygen *>(user);
   keygen->iwp->crypto->keygen(keygen->keybuf);
   llarp_thread_job job = {
     .user = user,
-    .work = iwp_inform_keygen
+    .work = &inform_keygen
   };
   llarp_logic_queue_job(keygen->iwp->logic, job);
 }
 
-void iwp_inform_genintro(void * user)
+void inform_gen_intro(void * user)
 {
   iwp_async_intro * intro = static_cast<iwp_async_intro *>(user);
   intro->hook(intro);
 }
 
-void iwp_do_genintro(void * user)
+void gen_intro(void * user)
 {
   iwp_async_intro * intro = static_cast<iwp_async_intro *>(user);
   llarp_sharedkey_t sharedkey;
@@ -44,7 +47,7 @@ void iwp_do_genintro(void * user)
   uint8_t tmp[64];
   llarp_thread_job job = {
     .user = user,
-    .work = &iwp_inform_genintro
+    .work = &inform_gen_intro
   };
   // S = TKE(a.k, b.k, n)
   crypto->transport_dh_client(sharedkey, intro->remote_pubkey, intro->secretkey, intro->nonce);
@@ -68,33 +71,33 @@ void iwp_do_genintro(void * user)
 }
 
 
-void iwp_inform_verify_introack(void * user)
+void inform_verify_introack(void * user)
 {
   iwp_async_introack * introack =  static_cast<iwp_async_introack *>(user);
   introack->hook(introack);
 }
 
 
-void iwp_do_verify_introack(void * user)
+void verify_introack(void * user)
 {
   iwp_async_introack * introack = static_cast<iwp_async_introack *>(user);
-  llarp_crypto * crypto = introack->iwp->crypto;
-  llarp_logic * logic = introack->iwp->logic;
+  auto crypto = introack->iwp->crypto;
+  auto logic = introack->iwp->logic;
 
   llarp_thread_job job = {
     .user = user,
-    .work = &iwp_inform_verify_introack
+    .work = &inform_verify_introack
   };
 
   llarp_hmac_t digest;
   llarp_sharedkey_t sharedkey;
   
-  uint8_t * hmac = introack->buf;
-  uint8_t * body = introack->buf + 32;
-  uint8_t * pubkey = introack->remote_pubkey;
-  uint8_t * secretkey = introack->secretkey;
-  uint8_t * nonce = introack->buf + 32;
-  uint8_t * token = introack->buf + 64;
+  auto hmac = introack->buf;
+  auto body = introack->buf + 32;
+  auto pubkey = introack->remote_pubkey;
+  auto secretkey = introack->secretkey;
+  auto nonce = introack->buf + 32;
+  auto token = introack->buf + 64;
   size_t bodysz = introack->sz - 32;
   llarp_buffer_t buf;
   buf.base = (char*) body;
@@ -109,7 +112,7 @@ void iwp_do_verify_introack(void * user)
   if(!llarp_eq(digest, hmac, 32))
   {
     // fail to verify hmac
-    introack->buf = 0;
+    introack->buf = nullptr;
     llarp_logic_queue_job(logic, job);
     return;
   }
@@ -119,6 +122,67 @@ void iwp_do_verify_introack(void * user)
   crypto->xchacha20(buf, sharedkey, nonce);
   // copy token
   memcpy(introack->token, token, 32);
+  llarp_logic_queue_job(logic, job);
+}
+
+  void inform_gen_session_start(void * user)
+  {
+     iwp_async_session_start * session = static_cast<iwp_async_session_start *>(user);
+     session->hook(session);
+  }
+  
+  void gen_session_start(void * user)
+  {
+    iwp_async_session_start * session = static_cast<iwp_async_session_start *>(user);
+    auto crypto = session->iwp->crypto;
+
+    auto dh = crypto->transport_dh_client;
+    auto shorthash = crypto->shorthash;
+    auto hmac = crypto->hmac;
+    auto encrypt = crypto->xchacha20;
+    
+    auto logic = session->iwp->logic;
+    auto a_sK = session->secretkey;
+    auto b_K = session->remote_pubkey;
+    auto N = session->nonce;
+    auto token = session->token;
+    auto K = session->sessionkey;
+
+    llarp_sharedkey_t e_K;
+    llarp_shorthash_t T;
+    llarp_buffer_t buf;
+
+    uint8_t tmp[64];
+
+    // T = HS(token + n)
+    memcpy(tmp, token, 32);
+    memcpy(tmp + 32, N, 32);
+    buf.base = (char *) tmp;
+    buf.sz = 64;
+    shorthash(&T, buf);
+    
+    // e_K = TKE(a.k, b.k, N)
+    dh(e_K, b_K, a_sK, N);
+    // K = TKE(a.k, b.k, T)
+    dh(K, b_K, a_sK, T);
+
+    // x = SE(e_K, token, n[0:24])
+    buf.base = (char *) (session->buf + 64);
+    buf.sz = 32;
+    memcpy(buf.base, token, 32);
+    encrypt(buf, e_K, N);
+
+    // h = MDS(n + x + w2, e_K)
+    buf.base = (char*) (session->buf + 32);
+    buf.sz = session->sz - 32;
+    hmac(session->buf, buf, e_K);
+    
+    // K = TKE(a.k, b.k, T)
+    dh(K, b_K, a_sK, T);
+
+    llarp_logic_queue_job(logic, {user, &inform_gen_session_start});
+  }
+  
 }
 
 extern "C" {
@@ -126,37 +190,25 @@ extern "C" {
 void iwp_call_async_keygen(struct llarp_async_iwp * iwp, struct iwp_async_keygen * keygen)
 {
   keygen->iwp = iwp;
-  struct llarp_thread_job job = {
-    .user = keygen,
-    .work = &iwp_do_keygen
-  };
-  llarp_threadpool_queue_job(iwp->worker, job);
+  llarp_threadpool_queue_job(iwp->worker, {keygen, &iwp::keygen});
 }
 
 void iwp_call_async_gen_intro(struct llarp_async_iwp * iwp, struct iwp_async_intro * intro)
 {
-  
   intro->iwp = iwp;
-  struct llarp_thread_job job = {
-    .user = intro,
-    .work = &iwp_do_genintro
-  };
-  llarp_threadpool_queue_job(iwp->worker, job);
+  llarp_threadpool_queue_job(iwp->worker, {intro, &iwp::gen_intro});
 }
 
 void iwp_call_async_verify_introack(struct llarp_async_iwp * iwp, struct iwp_async_introack * introack)
 {
   introack->iwp = iwp;
-  struct llarp_thread_job job = {
-    .user = introack,
-    .work = &iwp_do_verify_introack
-  };
-  llarp_threadpool_queue_job(iwp->worker, job);
+  llarp_threadpool_queue_job(iwp->worker, {introack, &iwp::verify_introack});
 }
 
 void iwp_call_async_gen_session_start(struct llarp_async_iwp * iwp, struct iwp_async_session_start * session)
 {
   session->iwp = iwp;
+  llarp_threadpool_queue_job(iwp->worker, {session, &iwp::gen_session_start});
 }
 
 void iwp_call_async_frame_decrypt(struct llarp_async_iwp * iwp, struct iwp_async_frame * frame)