add non blocking testing and better support for non blocking edge cases

examples/echoserver/echoserver.c

@@ -753,6 +753,12 @@ THREAD_RETURN WOLFSSH_THREAD echoserver_test(void* args)
     }
     myoptind = 0;      /* reset for test cases */
 
+#ifdef WOLFSSH_TEST_BLOCK
+    if (!nonBlock) {
+        err_sys("Use -N when testing forced non blocking");
+    }
+#endif
+
     if (wolfSSH_Init() != WS_SUCCESS) {
         fprintf(stderr, "Couldn't initialize wolfSSH.\n");
         exit(EXIT_FAILURE);

examples/sftpclient/sftpclient.c

@@ -937,6 +937,13 @@ THREAD_RETURN WOLFSSH_THREAD sftpclient_test(void* args)
     if (username == NULL)
         err_sys("client requires a username parameter.");
 
+
+#ifdef WOLFSSH_TEST_BLOCK
+    if (!nonBlock) {
+        err_sys("Use -N when testing forced non blocking");
+    }
+#endif
+
     ctx = wolfSSH_CTX_new(WOLFSSH_ENDPOINT_CLIENT, NULL);
     if (ctx == NULL)
         err_sys("Couldn't create wolfSSH client context.");

src/io.c

@@ -38,6 +38,16 @@
     #include <stddef.h>
 #endif
 
+#ifdef WOLFSSH_TEST_BLOCK
+    #define WOLFSSH_TEST_SERVER
+    #include "wolfssh/test.h"
+
+    /* percent of time that forced want read/write is done */
+    #ifndef WOLFSSH_BLOCK_PROB
+        #define WOLFSSH_BLOCK_PROB 75
+    #endif
+#endif
+
 
 /* allow I/O callback handlers whether user I/O or not */
 
@@ -300,7 +310,6 @@ static INLINE int LastError(void)
 #endif
 }
 
-
 /* The receive embedded callback
  *  return : nb bytes read, or error
  */
@@ -311,6 +320,14 @@ int wsEmbedRecv(WOLFSSH* ssh, void* data, word32 sz, void* ctx)
     int sd = *(int*)ctx;
     char* buf = (char*)data;
 
+#ifdef WOLFSSH_TEST_BLOCK
+    if (tcp_select(sd, 1) == WS_SELECT_RECV_READY &&
+            (rand() % 100) < WOLFSSH_BLOCK_PROB) {
+        printf("Forced read block\n");
+        return WS_CBIO_ERR_WANT_READ;
+    }
+#endif
+
     recvd = (int)RECV_FUNCTION(sd, buf, sz, ssh->rflags);
 
     recvd = TranslateReturnCode(recvd, sd);
@@ -363,6 +380,13 @@ int wsEmbedSend(WOLFSSH* ssh, void* data, word32 sz, void* ctx)
     int err;
     char* buf = (char*)data;
 
+#ifdef WOLFSSH_TEST_BLOCK
+    if ((rand() % 100) < WOLFSSH_BLOCK_PROB) {
+        printf("Forced write block\n");
+        return WS_CBIO_ERR_WANT_WRITE;
+    }
+#endif
+
     WLOG(WS_LOG_DEBUG,"Embed Send trying to send %d", sz);
 
 #ifdef MICROCHIP_MPLAB_HARMONY

src/ssh.c

@@ -277,7 +277,8 @@ int wolfSSH_accept(WOLFSSH* ssh)
             if (ssh->acceptState != ACCEPT_SERVER_VERSION_SENT &&
                 ssh->acceptState != ACCEPT_SERVER_USERAUTH_ACCEPT_SENT &&
                 ssh->acceptState != ACCEPT_SERVER_KEXINIT_SENT &&
-                ssh->acceptState != ACCEPT_KEYED) {
+                ssh->acceptState != ACCEPT_KEYED &&
+                ssh->acceptState != ACCEPT_SERVER_CHANNEL_ACCEPT_SENT) {
                 WLOG(WS_LOG_DEBUG, "Advancing accept state");
                 ssh->acceptState++;
             }
@@ -439,8 +440,6 @@ int wolfSSH_accept(WOLFSSH* ssh)
                     continue;
                 }
 #endif
-                ssh->acceptState = ACCEPT_CLIENT_SESSION_ESTABLISHED;
-                WLOG(WS_LOG_DEBUG, acceptState, "CLIENT_SESSION_ESTABLISHED");
 #if defined(WOLFSSH_SFTP) && !defined(NO_WOLFSSH_SERVER)
                 {
                     const char* cmd = wolfSSH_GetSessionCommand(ssh);
@@ -452,6 +451,8 @@ int wolfSSH_accept(WOLFSSH* ssh)
                     }
                 }
 #endif /* WOLFSSH_SFTP and !NO_WOLFSSH_SERVER */
+                ssh->acceptState = ACCEPT_CLIENT_SESSION_ESTABLISHED;
+                WLOG(WS_LOG_DEBUG, acceptState, "CLIENT_SESSION_ESTABLISHED");
                 break;
 
 #ifdef WOLFSSH_SCP
@@ -505,7 +506,6 @@ int wolfSSH_connect(WOLFSSH* ssh)
                 ssh->connectState != CONNECT_CLIENT_CHANNEL_OPEN_SESSION_SENT &&
                 ssh->connectState != CONNECT_CLIENT_CHANNEL_REQUEST_SENT) {
                 WLOG(WS_LOG_DEBUG, "Advancing connect state");
-                printf("advance connect state\n");
                 ssh->connectState++;
             }
 
@@ -670,8 +670,13 @@ int wolfSSH_connect(WOLFSSH* ssh)
                 }
                 if ( (ssh->error =
                         SendChannelOpenSession(ssh, newChannel)) < WS_SUCCESS) {
-
-                    ChannelDelete(newChannel, ssh->ctx->heap);
+                    if (ssh->error == WS_WANT_WRITE ||
+                            ssh->error == WS_WANT_READ) {
+                        ChannelAppend(ssh, newChannel);
+                    }
+                    else {
+                        ChannelDelete(newChannel, ssh->ctx->heap);
+                    }
                     WLOG(WS_LOG_DEBUG, connectError,
                         "SERVER_USERAUTH_ACCEPT_DONE", ssh->error);
                     return WS_FATAL_ERROR;