Configurable TCP_NODELAY option on network connections

[u/mdw/putty] / network.h

diff --git a/network.h b/network.h
index e205b87..3ec9eb7 100644 (file)
--- a/network.h
+++ b/network.h
@@ -24,8 +24,8 @@ struct socket_function_table {
     /* if p is NULL, it doesn't change the plug */
     /* but it does return the one it's using */
     void (*close) (Socket s);
-    void (*write) (Socket s, char *data, int len);
-    void (*write_oob) (Socket s, char *data, int len);
+    int (*write) (Socket s, char *data, int len);
+    int (*write_oob) (Socket s, char *data, int len);
     void (*flush) (Socket s);
     /* ignored by tcp, but vital for ssl */
     char *(*socket_error) (Socket s);
@@ -48,7 +48,13 @@ struct plug_function_table {
      *  - urgent==2. `data' points to `len' bytes of data,
      *    the first of which was the one at the Urgent mark.
      */
-    int (*accepting)(Plug p, struct sockaddr *addr, void *sock);
+    void (*sent) (Plug p, int bufsize);
+    /*
+     * The `sent' function is called when the pending send backlog
+     * on a socket is cleared or partially cleared. The new backlog
+     * size is passed in the `bufsize' parameter.
+     */
+    int (*accepting)(Plug p, void *sock);
     /*
      * returns 0 if the host at address addr is a valid host for connecting or error
      */
@@ -58,12 +64,13 @@ struct plug_function_table {
 void sk_init(void);                   /* called once at program startup */
 
 SockAddr sk_namelookup(char *host, char **canonicalname);
+void sk_getaddr(SockAddr addr, char *buf, int buflen);
 void sk_addr_free(SockAddr addr);
 
 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
-             Plug p);
+             int nodelay, Plug p);
 
-Socket sk_newlistenner(int port, Plug plug);
+Socket sk_newlistener(int port, Plug plug, int local_host_only);
 
 Socket sk_register(void *sock, Plug plug);
 
@@ -76,7 +83,8 @@ Socket sk_register(void *sock, Plug plug);
 #ifdef DEFINE_PLUG_METHOD_MACROS
 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))
 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))
-#define plug_accepting(p, addr, sock) (((*p)->accepting)(p, addr, sock))
+#define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))
+#define plug_accepting(p, sock) (((*p)->accepting)(p, sock))
 #endif
 
 /*
@@ -99,13 +107,29 @@ char *sk_addr_error(SockAddr addr);
 
 /*
  * Set the `frozen' flag on a socket. A frozen socket is one in
- * which all sends are buffered and receives are ignored. This is
- * so that (for example) a new port-forwarding can sit in limbo
- * until its associated SSH channel is ready, and then pending data
- * can be sent on.
+ * which all READABLE notifications are ignored, so that data is
+ * not accepted from the peer until the socket is unfrozen. This
+ * exists for two purposes:
+ * 
+ *  - Port forwarding: when a local listening port receives a
+ *    connection, we do not want to receive data from the new
+ *    socket until we have somewhere to send it. Hence, we freeze
+ *    the socket until its associated SSH channel is ready; then we
+ *    unfreeze it and pending data is delivered.
+ * 
+ *  - Socket buffering: if an SSH channel (or the whole connection)
+ *    backs up or presents a zero window, we must freeze the
+ *    associated local socket in order to avoid unbounded buffer
+ *    growth.
  */
 void sk_set_frozen(Socket sock, int is_frozen);
 
+/*
+ * Call this after an operation that might have tried to send on a
+ * socket, to clean up any pending network errors.
+ */
+void net_pending_errors(void);
+
 /********** SSL stuff **********/
 
 /*