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Diffstat (limited to 'tools/plink/network.h')
| -rw-r--r-- | tools/plink/network.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/tools/plink/network.h b/tools/plink/network.h new file mode 100644 index 000000000..b1b559047 --- /dev/null +++ b/tools/plink/network.h @@ -0,0 +1,247 @@ +/*
+ * Networking abstraction in PuTTY.
+ *
+ * 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 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
+
+#ifndef DONE_TYPEDEFS
+#define DONE_TYPEDEFS
+typedef struct config_tag Config;
+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;
+
+#ifndef OSSOCKET_DEFINED
+typedef void *OSSocket;
+#endif
+
+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 (*flush) (Socket s);
+ void (*set_private_ptr) (Socket s, void *ptr);
+ void *(*get_private_ptr) (Socket s);
+ void (*set_frozen) (Socket s, int is_frozen);
+ /* ignored by tcp, but vital for ssl */
+ const char *(*socket_error) (Socket s);
+};
+
+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.
+ */
+ 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, OSSocket sock);
+ /*
+ * returns 0 if the host at address addr is a valid host for connecting or error
+ */
+};
+
+/* proxy indirection layer */
+/* NB, control of 'addr' is passed via new_connection, which takes
+ * responsibility for freeing it */
+Socket new_connection(SockAddr addr, char *hostname,
+ int port, int privport,
+ int oobinline, int nodelay, int keepalive,
+ Plug plug, const Config *cfg);
+Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
+ const Config *cfg, int addressfamily);
+SockAddr name_lookup(char *host, int port, char **canonicalname,
+ const Config *cfg, int addressfamily);
+
+/* platform-dependent callback from new_connection() */
+/* (same caveat about addr as new_connection()) */
+Socket platform_new_connection(SockAddr addr, char *hostname,
+ int port, int privport,
+ int oobinline, int nodelay, int keepalive,
+ Plug plug, const Config *cfg);
+
+/* 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_hostname_is_local(char *name);
+int sk_address_is_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(char *srcaddr, int port, Plug plug, int local_host_only, int address_family);
+
+Socket sk_register(OSSocket 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_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, 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.
+ */
+#define sk_set_private_ptr(s, ptr) (((*s)->set_private_ptr) (s, ptr))
+#define sk_get_private_ptr(s) (((*s)->get_private_ptr) (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.
+ */
+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:
+ *
+ * - 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.
+ */
+#define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, 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);
+
+/*
+ * 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);
+
+/*
+ * Look up the local hostname; return value needs freeing.
+ * May return NULL.
+ */
+char *get_hostname(void);
+
+/********** 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
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