*
* 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;
+#ifndef DONE_TYPEDEFS
+#define DONE_TYPEDEFS
+typedef struct conf_tag Conf;
+typedef struct backend_tag Backend;
+typedef struct terminal_tag Terminal;
+#endif
+
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, const char *data, int len);
+ int (*write_oob) (Socket s, const char *data, int len);
+ void (*write_eof) (Socket s);
+ void (*flush) (Socket s);
+ void (*set_frozen) (Socket s, int is_frozen);
+ /* ignored by tcp, but vital for ssl */
+ const char *(*socket_error) (Socket s);
+ char *(*peer_info) (Socket s);
+};
+
+typedef union { void *p; int i; } accept_ctx_t;
+typedef Socket (*accept_fn_t)(accept_ctx_t ctx, Plug plug);
+
+struct plug_function_table {
+ void (*log)(Plug p, int type, SockAddr addr, int port,
+ const char *error_msg, int error_code);
+ /*
+ * Passes the client progress reports on the process of setting
+ * up the connection.
+ *
+ * - type==0 means we are about to try to connect to address
+ * `addr' (error_msg and error_code are ignored)
+ * - type==1 means we have failed to connect to address `addr'
+ * (error_msg and error_code are supplied). This is not a
+ * fatal error - we may well have other candidate addresses
+ * to fall back to. When it _is_ fatal, the closing()
+ * function will be called.
+ * - type==2 means that error_msg contains a line of generic
+ * logging information about setting up the connection. This
+ * will typically be a wodge of standard-error output from a
+ * proxy command, so the receiver should probably prefix it to
+ * indicate this.
+ */
+ int (*closing)
+ (Plug p, const 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, accept_fn_t constructor, accept_ctx_t ctx);
+ /*
+ * `accepting' is called only on listener-type sockets, and is
+ * passed a constructor function+context that will create a fresh
+ * Socket describing the connection. It returns nonzero if it
+ * doesn't want the connection for some reason, or 0 on success.
+ */
+};
+
+/* proxy indirection layer */
+/* NB, control of 'addr' is passed via new_connection, which takes
+ * responsibility for freeing it */
+Socket new_connection(SockAddr addr, const char *hostname,
+ int port, int privport,
+ int oobinline, int nodelay, int keepalive,
+ Plug plug, Conf *conf);
+Socket new_listener(const char *srcaddr, int port, Plug plug,
+ int local_host_only, Conf *conf, int addressfamily);
+SockAddr name_lookup(const char *host, int port, char **canonicalname,
+ Conf *conf, int addressfamily, void *frontend_for_logging,
+ const char *lookup_reason_for_logging);
+int proxy_for_destination (SockAddr addr, const char *hostname, int port,
+ Conf *conf);
+
+/* platform-dependent callback from new_connection() */
+/* (same caveat about addr as new_connection()) */
+Socket platform_new_connection(SockAddr addr, const char *hostname,
+ int port, int privport,
+ int oobinline, int nodelay, int keepalive,
+ Plug plug, Conf *conf);
+
+/* socket functions */
+
+void sk_init(void); /* called once at program startup */
+void sk_cleanup(void); /* called just before program exit */
+
+SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);
+SockAddr sk_nonamelookup(const char *host);
+void sk_getaddr(SockAddr addr, char *buf, int buflen);
+int sk_addr_needs_port(SockAddr addr);
+int sk_hostname_is_local(const char *name);
+int sk_address_is_local(SockAddr addr);
+int sk_address_is_special_local(SockAddr addr);
+int sk_addrtype(SockAddr addr);
+void sk_addrcopy(SockAddr addr, char *buf);
+void sk_addr_free(SockAddr addr);
+/* sk_addr_dup generates another SockAddr which contains the same data
+ * as the original one and can be freed independently. May not actually
+ * physically _duplicate_ it: incrementing a reference count so that
+ * one more free is required before it disappears is an acceptable
+ * implementation. */
+SockAddr sk_addr_dup(SockAddr addr);
+
+/* NB, control of 'addr' is passed via sk_new, which takes responsibility
+ * for freeing it, as for new_connection() */
+Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
+ int nodelay, int keepalive, Plug p);
+
+Socket sk_newlistener(const char *srcaddr, int port, Plug plug,
+ int local_host_only, int address_family);
+
+#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_write_eof(s) (((*s)->write_eof) (s))
+#define sk_flush(s) (((*s)->flush) (s))
+
+#ifdef DEFINE_PLUG_METHOD_MACROS
+#define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))
+#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, constructor, ctx) (((*p)->accepting)(p, constructor, ctx))
+#endif
/*
- * 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.
+ * Special error values are returned from sk_namelookup and sk_new
+ * if there's a problem. These functions extract an error message,
+ * or return NULL if there's no problem.
+ */
+const char *sk_addr_error(SockAddr 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:
*
- * - urgent==2. `data' points to `len' bytes of data, the first of
- * which was the one at the Urgent mark.
+ * - 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.
*
- * - urgent==3. An error has occurred on the socket. `data' points
- * to an error string, and `len' points to an error code.
+ * - 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.
*/
-typedef int (*sk_receiver_t)(Socket s, int urgent, char *data, int len);
+#define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))
-void sk_init(void); /* called once at program startup */
+/*
+ * Return a (dynamically allocated) string giving some information
+ * about the other end of the socket, suitable for putting in log
+ * files. May be NULL if nothing is available at all.
+ */
+#define sk_peer_info(s) (((*s)->peer_info) (s))
-SockAddr sk_namelookup(char *host, char **canonicalname);
-void sk_addr_free(SockAddr addr);
+/*
+ * Simple wrapper on getservbyname(), needed by ssh.c. Returns the
+ * port number, in host byte order (suitable for printf and so on).
+ * Returns 0 on failure. Any platform not supporting getservbyname
+ * can just return 0 - this function is not required to handle
+ * numeric port specifications.
+ */
+int net_service_lookup(char *service);
-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);
+/*
+ * Look up the local hostname; return value needs freeing.
+ * May return NULL.
+ */
+char *get_hostname(void);
/*
- * Each socket abstraction contains a `void *' private field in
- * which the client can keep state.
+ * Trivial socket implementation which just stores an error. Found in
+ * errsock.c.
+ */
+Socket new_error_socket(const char *errmsg, Plug plug);
+
+/* ----------------------------------------------------------------------
+ * Functions defined outside the network code, which have to be
+ * declared in this header file rather than the main putty.h because
+ * they use types defined here.
*/
-void sk_set_private_ptr(Socket s, void *ptr);
-void *sk_get_private_ptr(Socket s);
/*
- * Special error values are returned from sk_namelookup and sk_new
- * if there's a problem. These functions extract an error message,
- * or return NULL if there's no problem.
+ * Exports from be_misc.c.
*/
-char *sk_addr_error(SockAddr addr);
-char *sk_socket_error(Socket addr);
+void backend_socket_log(void *frontend, int type, SockAddr addr, int port,
+ const char *error_msg, int error_code, Conf *conf,
+ int session_started);
+#ifndef BUFCHAIN_TYPEDEF
+typedef struct bufchain_tag bufchain; /* rest of declaration in misc.c */
+#define BUFCHAIN_TYPEDEF
+#endif
+void log_proxy_stderr(Plug plug, bufchain *buf, const void *vdata, int len);
#endif
projects / PuTTY.git / blobdiff