X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/2c94fd1cbf32093be173ea6c4378caa109f73dd4..3ad9d396e3e57477b4da4b20665ca33edd5d7f67:/network.h

diff --git a/network.h b/network.h
index 528e92ab..4300fb2e 100644
--- a/network.h
+++ b/network.h
@@ -3,51 +3,96 @@
  *
  * The way this works is: a back end can choose to open any number
  * of sockets - including zero, which might be necessary in some.
- * It can register a function to be called when data comes in on
- * any given one, and it can call the networking abstraction to
- * send data without having to worry about blocking. The stuff
- * behind the abstraction takes care of selects and nonblocking
- * writes and all that sort of painful gubbins.
+ * It can register a bunch of callbacks (most notably for when 
+ * data is received) for each socket, and it can call the networking
+ * abstraction to send data without having to worry about blocking.
+ * The stuff behind the abstraction takes care of selects and
+ * nonblocking writes and all that sort of painful gubbins.
  */
 
 #ifndef PUTTY_NETWORK_H
 #define PUTTY_NETWORK_H
 
-typedef struct Socket_tag *Socket;
 typedef struct SockAddr_tag *SockAddr;
+/* pay attention to levels of indirection */
+typedef struct socket_function_table **Socket;
+typedef struct plug_function_table **Plug;
+
+struct socket_function_table {
+    Plug(*plug) (Socket s, Plug p);
+    /* use a different plug (return the old one) */
+    /* if p is NULL, it doesn't change the plug */
+    /* but it does return the one it's using */
+    void (*close) (Socket s);
+    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);
+};
+
+struct plug_function_table {
+    int (*closing)
+     (Plug p, char *error_msg, int error_code, int calling_back);
+    /* error_msg is NULL iff it is not an error (ie it closed normally) */
+    /* calling_back != 0 iff there is a Plug function */
+    /* currently running (would cure the fixme in try_send()) */
+    int (*receive) (Plug p, int urgent, char *data, int len);
+    /*
+     *  - urgent==0. `data' points to `len' bytes of perfectly
+     *    ordinary data.
+     * 
+     *  - urgent==1. `data' points to `len' bytes of data,
+     *    which were read from before an Urgent pointer.
+     * 
+     *  - urgent==2. `data' points to `len' bytes of data,
+     *    the first of which was the one at the Urgent mark.
+     */
+    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
+     */
+};
 
-/*
- * This is the function a client must register with each socket, to
- * receive data coming in on that socket. The parameter `urgent'
- * decides the meaning of `data' and `len':
- * 
- *  - urgent==0. `data' points to `len' bytes of perfectly ordinary
- *    data.
- * 
- *  - urgent==1. `data' points to `len' bytes of data, which were
- *    read from before an Urgent pointer.
- * 
- *  - urgent==2. `data' points to `len' bytes of data, the first of
- *    which was the one at the Urgent mark.
- * 
- *  - urgent==3. An error has occurred on the socket. `data' points
- *    to an error string, and `len' points to an error code.
- */
-typedef int (*sk_receiver_t)(Socket s, int urgent, char *data, int len);
 
 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, sk_receiver_t receiver);
-void sk_close(Socket s);
-void sk_write(Socket s, char *buf, int len);
-void sk_write_oob(Socket s, char *buf, int len);
+Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
+	      Plug p);
+
+Socket sk_newlistener(int port, Plug plug, int local_host_only);
+
+Socket sk_register(void *sock, Plug plug);
+
+#define sk_plug(s,p) (((*s)->plug) (s, p))
+#define sk_close(s) (((*s)->close) (s))
+#define sk_write(s,buf,len) (((*s)->write) (s, buf, len))
+#define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))
+#define sk_flush(s) (((*s)->flush) (s))
+
+#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_sent(p,bufsize) (((*p)->sent) (p, bufsize))
+#define plug_accepting(p, sock) (((*p)->accepting)(p, sock))
+#endif
 
 /*
  * Each socket abstraction contains a `void *' private field in
  * which the client can keep state.
+ *
+ * This is perhaps unnecessary now that we have the notion of a plug,
+ * but there is some existing code that uses it, so it stays.
  */
 void sk_set_private_ptr(Socket s, void *ptr);
 void *sk_get_private_ptr(Socket s);
@@ -58,6 +103,61 @@ void *sk_get_private_ptr(Socket s);
  * or return NULL if there's no problem.
  */
 char *sk_addr_error(SockAddr addr);
-char *sk_socket_error(Socket addr);
+#define sk_socket_error(s) (((*s)->socket_error) (s))
+
+/*
+ * Set the `frozen' flag on a socket. A frozen socket is one in
+ * 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);
+
+/********** SSL stuff **********/
+
+/*
+ * This section is subject to change, but you get the general idea
+ * of what it will eventually look like.
+ */
+
+typedef struct certificate *Certificate;
+typedef struct our_certificate *Our_Certificate;
+    /* to be defined somewhere else, somehow */
+
+typedef struct ssl_client_socket_function_table **SSL_Client_Socket;
+typedef struct ssl_client_plug_function_table **SSL_Client_Plug;
+
+struct ssl_client_socket_function_table {
+    struct socket_function_table base;
+    void (*renegotiate) (SSL_Client_Socket s);
+    /* renegotiate the cipher spec */
+};
+
+struct ssl_client_plug_function_table {
+    struct plug_function_table base;
+    int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]);
+    /* do we accept this certificate chain?  If not, why not? */
+    /* cert[0] is the server's certificate, cert[] is NULL-terminated */
+    /* the last certificate may or may not be the root certificate */
+     Our_Certificate(*client_cert) (SSL_Client_Plug p);
+    /* the server wants us to identify ourselves */
+    /* may return NULL if we want anonymity */
+};
+
+SSL_Client_Socket sk_ssl_client_over(Socket s,	/* pre-existing (tcp) connection */
+				     SSL_Client_Plug p);
+
+#define sk_renegotiate(s) (((*s)->renegotiate) (s))
 
 #endif