ames, mesa: miscellaneous stuff (#754)

This PR does all kinds of stuff. The main ones are the following:

The udp receive buffer for ames and mesa is now statically allocated.
The sending buffer for ames is also statically allocated, so now we use
`uv_udp_try_send` instead of `uv_udp_send` in ames.

The meaning of the bitset in the mesa pending request structure is
different. It used to answer the question whether we have an outstanding
request for a particular fragment, whereas now it answers the question
"do we have this fragment?".

The misordered queue for mesa is now arbitrarily large instead of 8
fragments long. This means that we can receive fragments in any order.

build.zig

@@ -502,6 +502,11 @@ fn buildBinary(
                 .file = "pkg/noun/hashtable_tests.c",
                 .deps = noun_test_deps,
             },
+            .{
+                .name = "hamt-test",
+                .file = "pkg/vere/hamt_test.c",
+                .deps = vere_test_deps,
+            },
             .{
                 .name = "jets-test",
                 .file = "pkg/noun/jets_tests.c",

pkg/vere/io/ames.c

@@ -14,6 +14,8 @@
 
 #include <arpa/inet.h>
 
+static c3_y pac_y[4096];
+
 #define FINE_PAGE      4096             //  packets per page
 #define FINE_FRAG      1024             //  bytes per fragment packet
 #define FINE_PATH_MAX   384             //  longest allowed scry path
@@ -252,7 +254,6 @@ _ames_pact_free(u3_pact* pac_u)
       u3_pier_bail(u3_king_stub());
   }
 
-  c3_free(pac_u->hun_y);
   c3_free(pac_u);
 }
 
@@ -696,7 +697,7 @@ _fine_etch_response(u3_pact* pac_u)
   pre_w = _ames_prel_size(&pac_u->hed_u);
   pur_w = _fine_purr_size(&pac_u->pur_u);
   pac_u->len_w = HEAD_SIZE + pre_w + pur_w;
-  pac_u->hun_y = c3_calloc(pac_u->len_w);
+  pac_u->hun_y = pac_y;
 
   //  skip the header until we know what the mug should be
   //
@@ -735,14 +736,14 @@ _lane_scry_path(u3_noun who)
 /* _ames_send_cb(): send callback.
 */
 static void
-_ames_send_cb(uv_udp_send_t* req_u, c3_i sas_i)
+_ames_send_cb(u3_pact* pac_u, c3_i sas_i)
 {
-  u3_pact* pac_u = (u3_pact*)req_u;
   u3_ames* sam_u = pac_u->sam_u;
 
-  if ( !sas_i ) {
+  if ( sas_i >= 0 ) {
     net_o = c3y;
   }
+
   else if ( c3y == net_o ) {
     u3l_log("ames: send fail: %s", uv_strerror(sas_i));
     net_o = c3n;
@@ -776,15 +777,11 @@ _ames_send(u3_pact* pac_u)
 
     {
       uv_buf_t buf_u = uv_buf_init((c3_c*)pac_u->hun_y, pac_u->len_w);
-      c3_i     sas_i = uv_udp_send(&pac_u->snd_u,
-                                   &u3_Host.wax_u,
-                                   &buf_u, 1,
-                                   (const struct sockaddr*)&add_u,
-                                   _ames_send_cb);
-
-      if ( sas_i ) {
-        _ames_send_cb(&pac_u->snd_u, sas_i);
-      }
+      c3_i     sas_i = uv_udp_try_send(&u3_Host.wax_u,
+                                       &buf_u, 1,
+                                       (const struct sockaddr*)&add_u);
+
+      _ames_send_cb(pac_u, sas_i);
     }
   }
 }
@@ -1344,7 +1341,7 @@ _ames_ef_send(u3_ames* sam_u, u3_noun lan, u3_noun pac)
     pac_u->sam_u = sam_u;
     pac_u->lan_u = lan_u;
     pac_u->len_w = u3r_met(3, pac);
-    pac_u->hun_y = c3_malloc(pac_u->len_w);
+    pac_u->hun_y = pac_y;
 
     u3r_bytes(0, pac_u->len_w, pac_u->hun_y, pac);
 
@@ -1977,7 +1974,7 @@ _ames_try_forward(u3_pact* pac_u)
     old_y = pac_u->hun_y;
 
     pac_u->len_w += 6;
-    pac_u->hun_y = c3_calloc(pac_u->len_w);
+    pac_u->hun_y = pac_y;
 
     cur_w = 0;
 
@@ -2030,13 +2027,11 @@ _ames_hear(u3_ames* sam_u,
   //
   if ( c3y == u3_stun_is_request(hun_y, len_w) ) {
       _stun_on_request(sam_u, hun_y, adr_u);
-      c3_free(hun_y);
   }
   else if ( c3y == u3_stun_is_our_response(hun_y,
                                            sam_u->sun_u.tid_y, len_w) )
   {
     _stun_on_response(sam_u, hun_y, len_w);
-    c3_free(hun_y);
   }
   else {
     struct sockaddr_in* add_u = (struct sockaddr_in*)adr_u;
@@ -2054,7 +2049,6 @@ _ames_hear(u3_ames* sam_u,
                 sam_u->sat_u.hed_d);
       }
 
-      c3_free(hun_y);
       return;
     }