fix: stop parliament accept starvation on outbound dial (0.9.22)

Peer dial used per-step read timeouts so a stuck handshake could block the
single-threaded daemon for tens of seconds; inbound hellos piled up unread
(CLOSE-WAIT). Use a wall-clock dial budget, drain accepts before each dial,
skip self, and only one side initiates idle polls.

Co-authored-by: Cursor <cursoragent@cursor.com>

include/cst_peer.h

@@ -24,6 +24,7 @@ typedef struct {
 } cst_peer_session_t;
 
 /* Dial host:port, prove our cert, verify theirs, establish AEAD session.
+ * timeout_ms is a wall-clock budget for connect+handshake+kx (not per-read).
  * Leaves sock open for post-handshake sync; call cst_peer_close. */
 int cst_peer_dial(const char *host, int port, const cst_realm_cert_t *self,
                   const uint8_t self_sk[64], const uint8_t realm_pk[32],

include/cst_version.h

@@ -3,7 +3,7 @@
 
 #define CST_VERSION_MAJOR 0
 #define CST_VERSION_MINOR 9
-#define CST_VERSION_PATCH 20
+#define CST_VERSION_PATCH 22
 
 #define CST_VERSION_STR_(x) #x
 #define CST_VERSION_STR(x) CST_VERSION_STR_(x)

src/parliament_daemon.c

@@ -272,43 +272,59 @@ int cst_parliament_daemon_run(const char *password, const char *instance_id,
   signal(SIGHUP, on_sig);
 #endif
   g_stop = 0;
-  int tick = 0, idle = 0;
+  int tick = 0, idle = 0, dial_rr = 0;
   while (!g_stop) {
     cst_peer_session_t sess;
     char herr[128];
-    /* Accept wait backs off when idle so a quiet seat barely wakes. */
+    /* Prefer accept: a blocking outbound dial used to starve inbound peers
-    int accept_ms = idle > 20 ? 2000 : idle > 5 ? 1000 : 400;
+     * (CLOSE-WAIT + unread hello ~385B on :9100). Drain the backlog first. */
+    int accepted = 0;
+    for (;;) {
+      int accept_ms = accepted > 0 ? 50 : (idle > 20 ? 800 : idle > 5 ? 400 : 200);
       if (cst_peer_accept((intptr_t)ls, &cert, sk, realm.pk, accept_ms, &sess,
-                        herr, sizeof(herr)) == 0) {
+                          herr, sizeof(herr)) != 0)
+        break;
       sync_on_session(&sess);
       cst_peer_close(&sess);
+      accepted++;
       idle = 0;
-    } else {
+      if (accepted >= 8)
-      idle++;
+        break;
     }
+    if (accepted == 0)
+      idle++;
+
     int push = cst_parliament_sync_pending();
     tick++;
-    /* Dial peers on push, or periodically (slower while idle). */
+    /* At most one outbound dial per loop turn, short wall budget, so accept
-    int period = idle > 20 ? 45 : idle > 5 ? 20 : 8;
+     * keeps pace. Lexicographic rule avoids A↔B mutual-dial deadlock unless
+     * we have a local push to deliver. */
+    int period = idle > 20 ? 30 : idle > 5 ? 12 : 6;
     if ((push || tick % period == 0) && disc) {
       cst_peer_info_t peers[16];
       int n = cst_discover_peers(disc, peers, 16);
-      if (n > 0 || push) {
+      int tried = 0;
-        for (int i = 0; i < n; i++) {
+      for (int k = 0; k < n; k++) {
+        int i = (dial_rr + k) % n;
         if (peers[i].port <= 0)
           continue;
+        if (!strcmp(peers[i].instance_id, instance_id))
+          continue; /* never dial ourselves */
+        if (!push && strcmp(instance_id, peers[i].instance_id) > 0)
+          continue; /* lower id initiates idle polls */
+        dial_rr = (i + 1) % n;
         if (cst_peer_dial(peers[i].host, peers[i].port, &cert, sk, realm.pk,
-                            3000, &sess, herr, sizeof(herr)) == 0) {
+                          2500, &sess, herr, sizeof(herr)) == 0) {
           sync_on_session(&sess);
           cst_peer_close(&sess);
           idle = 0;
         }
+        tried = 1;
+        break; /* one dial then go back to accept */
       }
-      }
+      if (push && (tried || n == 0))
-      if (push)
         cst_parliament_sync_ack();
     }
-    /* No extra sleep: accept_ms already paced the loop. */
   }
   if (disc)
     cst_discover_stop(disc);
@@ -401,12 +417,13 @@ int cst_parliament_daemon_start(const char *password, const char *instance_id,
       snprintf(err, err_sz, "service did not start");
     return -1;
   }
-  /* Child: detach. */
+  /* Child: detach fully so SSH/nohup callers are not held by open stdio. */
   setsid();
   int fd = open("/dev/null", O_RDWR);
   if (fd >= 0) {
     dup2(fd, 0);
-    /* Keep stderr for service banner until closed by operator logs. */
+    dup2(fd, 1);
+    dup2(fd, 2);
     if (fd > 2)
       close(fd);
   }

src/peer_auth.c

@@ -13,6 +13,33 @@
 #include <string.h>
 #include <time.h>
 
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <sys/time.h>
+#endif
+
+/* Wall-clock deadline so a multi-step handshake cannot stretch to
+ * N_steps * timeout_ms (that starved the daemon accept loop). */
+static int64_t peer_now_ms(void) {
+#ifdef _WIN32
+  return (int64_t)GetTickCount64();
+#else
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  return (int64_t)tv.tv_sec * 1000 + (int64_t)tv.tv_usec / 1000;
+#endif
+}
+
+static int peer_remain_ms(int64_t deadline_ms) {
+  int64_t left = deadline_ms - peer_now_ms();
+  if (left <= 0)
+    return 0;
+  if (left > 600000)
+    return 600000;
+  return (int)left;
+}
+
 static void hex_encode(const uint8_t *in, size_t n, char *out) {
   static const char *H = "0123456789abcdef";
   for (size_t i = 0; i < n; i++) {
@@ -379,48 +406,60 @@ static int recv_sealed(cst_peer_session_t *sess, uint8_t **out, size_t *out_n,
 
 static int handshake_as_client(os_socket_t s, const cst_realm_cert_t *self,
                                const uint8_t self_sk[64],
-                               const uint8_t realm_pk[32], int timeout_ms,
+                               const uint8_t realm_pk[32], int64_t deadline_ms,
                                cst_realm_cert_t *remote) {
-  if (send_hello(s, self, timeout_ms) != 0)
+  int t;
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_hello(s, self, t) != 0)
     return -1;
   uint8_t nonce[32];
-  if (read_chal(s, timeout_ms, nonce) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || read_chal(s, t, nonce) != 0)
     return -1;
-  if (send_auth(s, self_sk, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      send_auth(s, self_sk, nonce, t) != 0)
     return -1;
-  if (read_hello(s, realm_pk, timeout_ms, remote) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      read_hello(s, realm_pk, t, remote) != 0)
     return -1;
   if (fill_random(nonce, 32) != 0)
     return -1;
-  if (send_chal(s, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_chal(s, nonce, t) != 0)
     return -1;
-  if (read_auth(s, remote, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      read_auth(s, remote, nonce, t) != 0)
     return -1;
-  if (send_ok(s, timeout_ms) != 0 || read_ok(s, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_ok(s, t) != 0)
+    return -1;
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || read_ok(s, t) != 0)
     return -1;
   return 0;
 }
 
 static int handshake_as_server(os_socket_t s, const cst_realm_cert_t *self,
                                const uint8_t self_sk[64],
-                               const uint8_t realm_pk[32], int timeout_ms,
+                               const uint8_t realm_pk[32], int64_t deadline_ms,
                                cst_realm_cert_t *remote) {
-  if (read_hello(s, realm_pk, timeout_ms, remote) != 0)
+  int t;
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      read_hello(s, realm_pk, t, remote) != 0)
     return -1;
   uint8_t nonce[32];
   if (fill_random(nonce, 32) != 0)
     return -1;
-  if (send_chal(s, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_chal(s, nonce, t) != 0)
     return -1;
-  if (read_auth(s, remote, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      read_auth(s, remote, nonce, t) != 0)
     return -1;
-  if (send_hello(s, self, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_hello(s, self, t) != 0)
     return -1;
-  if (read_chal(s, timeout_ms, nonce) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || read_chal(s, t, nonce) != 0)
     return -1;
-  if (send_auth(s, self_sk, nonce, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 ||
+      send_auth(s, self_sk, nonce, t) != 0)
     return -1;
-  if (read_ok(s, timeout_ms) != 0 || send_ok(s, timeout_ms) != 0)
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || read_ok(s, t) != 0)
+    return -1;
+  if ((t = peer_remain_ms(deadline_ms)) <= 0 || send_ok(s, t) != 0)
     return -1;
   return 0;
 }
@@ -433,15 +472,19 @@ int cst_peer_dial(const char *host, int port, const cst_realm_cert_t *self,
     err[0] = 0;
   if (!host || !self || !self_sk || !realm_pk || !out)
     return -1;
+  if (timeout_ms <= 0)
+    timeout_ms = 3000;
+  int64_t deadline = peer_now_ms() + timeout_ms;
   os_net_init();
-  os_socket_t s = os_net_connect(host, port, timeout_ms);
+  int t = peer_remain_ms(deadline);
+  os_socket_t s = os_net_connect(host, port, t);
   if (s == OS_SOCKET_BAD) {
     if (err && err_sz)
       snprintf(err, err_sz, "connect failed");
     return -1;
   }
   cst_realm_cert_t remote;
-  if (handshake_as_client(s, self, self_sk, realm_pk, timeout_ms, &remote) !=
+  if (handshake_as_client(s, self, self_sk, realm_pk, deadline, &remote) !=
       0) {
     if (err && err_sz)
       snprintf(err, err_sz, "peer handshake failed");
@@ -453,7 +496,8 @@ int cst_peer_dial(const char *host, int port, const cst_realm_cert_t *self,
   snprintf(out->host, sizeof(out->host), "%s", host);
   out->port = port;
   out->sock = (intptr_t)s;
-  if (peer_kx(s, 1, out->aead_key, timeout_ms) != 0) {
+  t = peer_remain_ms(deadline);
+  if (t <= 0 || peer_kx(s, 1, out->aead_key, t) != 0) {
     if (err && err_sz)
       snprintf(err, err_sz, "peer key exchange failed");
     cst_peer_close(out);
@@ -471,15 +515,21 @@ int cst_peer_accept(intptr_t listen_sock, const cst_realm_cert_t *self,
     err[0] = 0;
   if (!self || !self_sk || !realm_pk || !out)
     return -1;
+  if (timeout_ms <= 0)
+    timeout_ms = 3000;
   int timed = 0;
+  /* Accept wait uses the caller budget; handshake+kx share a fresh deadline
+   * after the connection is taken, so a long accept wait does not shrink the
+   * crypto exchange to zero. */
   os_socket_t s = os_net_accept((os_socket_t)listen_sock, timeout_ms, &timed);
   if (s == OS_SOCKET_BAD) {
     if (err && err_sz)
       snprintf(err, err_sz, timed ? "accept timeout" : "accept failed");
     return -1;
   }
+  int64_t deadline = peer_now_ms() + (timeout_ms < 3000 ? 3000 : timeout_ms);
   cst_realm_cert_t remote;
-  if (handshake_as_server(s, self, self_sk, realm_pk, timeout_ms, &remote) !=
+  if (handshake_as_server(s, self, self_sk, realm_pk, deadline, &remote) !=
       0) {
     if (err && err_sz)
       snprintf(err, err_sz, "peer handshake failed");
@@ -491,7 +541,8 @@ int cst_peer_accept(intptr_t listen_sock, const cst_realm_cert_t *self,
   os_net_peer(s, out->host, sizeof(out->host));
   out->port = 0;
   out->sock = (intptr_t)s;
-  if (peer_kx(s, 0, out->aead_key, timeout_ms) != 0) {
+  int t = peer_remain_ms(deadline);
+  if (t <= 0 || peer_kx(s, 0, out->aead_key, t) != 0) {
     if (err && err_sz)
       snprintf(err, err_sz, "peer key exchange failed");
     cst_peer_close(out);

tests/test_peer_auth.c

@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 typedef struct {
   os_socket_t listen;
@@ -109,8 +110,22 @@ int main(void) {
   pthread_join(th, NULL);
   assert(!srv2.ok);
 
+  /* Wall-clock dial budget: listener that never accepts must fail fast. */
+  os_socket_t ls3 = os_net_listen("127.0.0.1", 0, err, sizeof(err));
+  assert(ls3 != OS_SOCKET_BAD);
+  int port3 = os_net_port(ls3);
+  struct timespec t0, t1;
+  clock_gettime(CLOCK_MONOTONIC, &t0);
+  assert(cst_peer_dial("127.0.0.1", port3, &ca, ska, realm.pk, 800, &sess, err,
+                       sizeof(err)) != 0);
+  clock_gettime(CLOCK_MONOTONIC, &t1);
+  long ms = (long)((t1.tv_sec - t0.tv_sec) * 1000 +
+                   (t1.tv_nsec - t0.tv_nsec) / 1000000);
+  assert(ms >= 400 && ms < 2500);
+
   os_net_close(ls);
   os_net_close(ls2);
+  os_net_close(ls3);
   os_net_cleanup();
   puts("test_peer_auth: OK");
   return 0;