| blob | 4c9fef033c748b572fd58e15baa6664671167df1 |
1 /*\r
2 * Networking abstraction in PuTTY.\r
3 *\r
4 * The way this works is: a back end can choose to open any number\r
5 * of sockets - including zero, which might be necessary in some.\r
6 * It can register a bunch of callbacks (most notably for when \r
7 * data is received) for each socket, and it can call the networking\r
8 * abstraction to send data without having to worry about blocking.\r
9 * The stuff behind the abstraction takes care of selects and\r
10 * nonblocking writes and all that sort of painful gubbins.\r
11 */\r
12 \r
13 #ifndef PUTTY_NETWORK_H\r
14 #define PUTTY_NETWORK_H\r
15 \r
16 #ifndef DONE_TYPEDEFS\r
17 #define DONE_TYPEDEFS\r
18 typedef struct conf_tag Conf;\r
19 typedef struct backend_tag Backend;\r
20 typedef struct terminal_tag Terminal;\r
21 #endif\r
22 \r
23 typedef struct SockAddr_tag *SockAddr;\r
24 /* pay attention to levels of indirection */\r
25 typedef struct socket_function_table **Socket;\r
26 typedef struct plug_function_table **Plug;\r
27 \r
28 #ifndef OSSOCKET_DEFINED\r
29 typedef void *OSSocket;\r
30 #endif\r
31 \r
32 struct socket_function_table {\r
33 Plug(*plug) (Socket s, Plug p);\r
34 /* use a different plug (return the old one) */\r
35 /* if p is NULL, it doesn't change the plug */\r
36 /* but it does return the one it's using */\r
37 void (*close) (Socket s);\r
38 int (*write) (Socket s, const char *data, int len);\r
39 int (*write_oob) (Socket s, const char *data, int len);\r
40 void (*write_eof) (Socket s);\r
41 void (*flush) (Socket s);\r
42 void (*set_private_ptr) (Socket s, void *ptr);\r
43 void *(*get_private_ptr) (Socket s);\r
44 void (*set_frozen) (Socket s, int is_frozen);\r
45 /* ignored by tcp, but vital for ssl */\r
46 const char *(*socket_error) (Socket s);\r
47 };\r
48 \r
49 struct plug_function_table {\r
50 void (*log)(Plug p, int type, SockAddr addr, int port,\r
51 const char *error_msg, int error_code);\r
52 /*\r
53 * Passes the client progress reports on the process of setting\r
54 * up the connection.\r
55 * \r
56 * - type==0 means we are about to try to connect to address\r
57 * `addr' (error_msg and error_code are ignored)\r
58 * - type==1 means we have failed to connect to address `addr'\r
59 * (error_msg and error_code are supplied). This is not a\r
60 * fatal error - we may well have other candidate addresses\r
61 * to fall back to. When it _is_ fatal, the closing()\r
62 * function will be called.\r
63 */\r
64 int (*closing)\r
65 (Plug p, const char *error_msg, int error_code, int calling_back);\r
66 /* error_msg is NULL iff it is not an error (ie it closed normally) */\r
67 /* calling_back != 0 iff there is a Plug function */\r
68 /* currently running (would cure the fixme in try_send()) */\r
69 int (*receive) (Plug p, int urgent, char *data, int len);\r
70 /*\r
71 * - urgent==0. `data' points to `len' bytes of perfectly\r
72 * ordinary data.\r
73 * \r
74 * - urgent==1. `data' points to `len' bytes of data,\r
75 * which were read from before an Urgent pointer.\r
76 * \r
77 * - urgent==2. `data' points to `len' bytes of data,\r
78 * the first of which was the one at the Urgent mark.\r
79 */\r
80 void (*sent) (Plug p, int bufsize);\r
81 /*\r
82 * The `sent' function is called when the pending send backlog\r
83 * on a socket is cleared or partially cleared. The new backlog\r
84 * size is passed in the `bufsize' parameter.\r
85 */\r
86 int (*accepting)(Plug p, OSSocket sock);\r
87 /*\r
88 * returns 0 if the host at address addr is a valid host for connecting or error\r
89 */\r
90 };\r
91 \r
92 /* proxy indirection layer */\r
93 /* NB, control of 'addr' is passed via new_connection, which takes\r
94 * responsibility for freeing it */\r
95 Socket new_connection(SockAddr addr, char *hostname,\r
96 int port, int privport,\r
97 int oobinline, int nodelay, int keepalive,\r
98 Plug plug, Conf *conf);\r
99 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,\r
100 Conf *conf, int addressfamily);\r
101 SockAddr name_lookup(char *host, int port, char **canonicalname,\r
102 Conf *conf, int addressfamily);\r
103 \r
104 /* platform-dependent callback from new_connection() */\r
105 /* (same caveat about addr as new_connection()) */\r
106 Socket platform_new_connection(SockAddr addr, char *hostname,\r
107 int port, int privport,\r
108 int oobinline, int nodelay, int keepalive,\r
109 Plug plug, Conf *conf);\r
110 \r
111 /* socket functions */\r
112 \r
113 void sk_init(void); /* called once at program startup */\r
114 void sk_cleanup(void); /* called just before program exit */\r
115 \r
116 SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);\r
117 SockAddr sk_nonamelookup(const char *host);\r
118 void sk_getaddr(SockAddr addr, char *buf, int buflen);\r
119 int sk_hostname_is_local(const char *name);\r
120 int sk_address_is_local(SockAddr addr);\r
121 int sk_address_is_special_local(SockAddr addr);\r
122 int sk_addrtype(SockAddr addr);\r
123 void sk_addrcopy(SockAddr addr, char *buf);\r
124 void sk_addr_free(SockAddr addr);\r
125 /* sk_addr_dup generates another SockAddr which contains the same data\r
126 * as the original one and can be freed independently. May not actually\r
127 * physically _duplicate_ it: incrementing a reference count so that\r
128 * one more free is required before it disappears is an acceptable\r
129 * implementation. */\r
130 SockAddr sk_addr_dup(SockAddr addr);\r
131 \r
132 /* NB, control of 'addr' is passed via sk_new, which takes responsibility\r
133 * for freeing it, as for new_connection() */\r
134 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,\r
135 int nodelay, int keepalive, Plug p);\r
136 \r
137 Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only, int address_family);\r
138 \r
139 Socket sk_register(OSSocket sock, Plug plug);\r
140 \r
141 #define sk_plug(s,p) (((*s)->plug) (s, p))\r
142 #define sk_close(s) (((*s)->close) (s))\r
143 #define sk_write(s,buf,len) (((*s)->write) (s, buf, len))\r
144 #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))\r
145 #define sk_write_eof(s) (((*s)->write_eof) (s))\r
146 #define sk_flush(s) (((*s)->flush) (s))\r
147 \r
148 #ifdef DEFINE_PLUG_METHOD_MACROS\r
149 #define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))\r
150 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))\r
151 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))\r
152 #define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))\r
153 #define plug_accepting(p, sock) (((*p)->accepting)(p, sock))\r
154 #endif\r
155 \r
156 /*\r
157 * Each socket abstraction contains a `void *' private field in\r
158 * which the client can keep state.\r
159 *\r
160 * This is perhaps unnecessary now that we have the notion of a plug,\r
161 * but there is some existing code that uses it, so it stays.\r
162 */\r
163 #define sk_set_private_ptr(s, ptr) (((*s)->set_private_ptr) (s, ptr))\r
164 #define sk_get_private_ptr(s) (((*s)->get_private_ptr) (s))\r
165 \r
166 /*\r
167 * Special error values are returned from sk_namelookup and sk_new\r
168 * if there's a problem. These functions extract an error message,\r
169 * or return NULL if there's no problem.\r
170 */\r
171 const char *sk_addr_error(SockAddr addr);\r
172 #define sk_socket_error(s) (((*s)->socket_error) (s))\r
173 \r
174 /*\r
175 * Set the `frozen' flag on a socket. A frozen socket is one in\r
176 * which all READABLE notifications are ignored, so that data is\r
177 * not accepted from the peer until the socket is unfrozen. This\r
178 * exists for two purposes:\r
179 * \r
180 * - Port forwarding: when a local listening port receives a\r
181 * connection, we do not want to receive data from the new\r
182 * socket until we have somewhere to send it. Hence, we freeze\r
183 * the socket until its associated SSH channel is ready; then we\r
184 * unfreeze it and pending data is delivered.\r
185 * \r
186 * - Socket buffering: if an SSH channel (or the whole connection)\r
187 * backs up or presents a zero window, we must freeze the\r
188 * associated local socket in order to avoid unbounded buffer\r
189 * growth.\r
190 */\r
191 #define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))\r
192 \r
193 /*\r
194 * Call this after an operation that might have tried to send on a\r
195 * socket, to clean up any pending network errors.\r
196 */\r
197 void net_pending_errors(void);\r
198 \r
199 /*\r
200 * Simple wrapper on getservbyname(), needed by ssh.c. Returns the\r
201 * port number, in host byte order (suitable for printf and so on).\r
202 * Returns 0 on failure. Any platform not supporting getservbyname\r
203 * can just return 0 - this function is not required to handle\r
204 * numeric port specifications.\r
205 */\r
206 int net_service_lookup(char *service);\r
207 \r
208 /*\r
209 * Look up the local hostname; return value needs freeing.\r
210 * May return NULL.\r
211 */\r
212 char *get_hostname(void);\r
213 \r
214 /********** SSL stuff **********/\r
215 \r
216 /*\r
217 * This section is subject to change, but you get the general idea\r
218 * of what it will eventually look like.\r
219 */\r
220 \r
221 typedef struct certificate *Certificate;\r
222 typedef struct our_certificate *Our_Certificate;\r
223 /* to be defined somewhere else, somehow */\r
224 \r
225 typedef struct ssl_client_socket_function_table **SSL_Client_Socket;\r
226 typedef struct ssl_client_plug_function_table **SSL_Client_Plug;\r
227 \r
228 struct ssl_client_socket_function_table {\r
229 struct socket_function_table base;\r
230 void (*renegotiate) (SSL_Client_Socket s);\r
231 /* renegotiate the cipher spec */\r
232 };\r
233 \r
234 struct ssl_client_plug_function_table {\r
235 struct plug_function_table base;\r
236 int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]);\r
237 /* do we accept this certificate chain? If not, why not? */\r
238 /* cert[0] is the server's certificate, cert[] is NULL-terminated */\r
239 /* the last certificate may or may not be the root certificate */\r
240 Our_Certificate(*client_cert) (SSL_Client_Plug p);\r
241 /* the server wants us to identify ourselves */\r
242 /* may return NULL if we want anonymity */\r
243 };\r
244 \r
245 SSL_Client_Socket sk_ssl_client_over(Socket s, /* pre-existing (tcp) connection */\r
246 SSL_Client_Plug p);\r
247 \r
248 #define sk_renegotiate(s) (((*s)->renegotiate) (s))\r
249 \r
250 #endif\r