| blob | 3c72024950c6e4a2c8b58284a489d19e395ca80b |
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 struct socket_function_table {\r
29 Plug(*plug) (Socket s, Plug p);\r
30 /* use a different plug (return the old one) */\r
31 /* if p is NULL, it doesn't change the plug */\r
32 /* but it does return the one it's using */\r
33 void (*close) (Socket s);\r
34 int (*write) (Socket s, const char *data, int len);\r
35 int (*write_oob) (Socket s, const char *data, int len);\r
36 void (*write_eof) (Socket s);\r
37 void (*flush) (Socket s);\r
38 void (*set_frozen) (Socket s, int is_frozen);\r
39 /* ignored by tcp, but vital for ssl */\r
40 const char *(*socket_error) (Socket s);\r
41 char *(*peer_info) (Socket s);\r
42 };\r
43 \r
44 typedef union { void *p; int i; } accept_ctx_t;\r
45 typedef Socket (*accept_fn_t)(accept_ctx_t ctx, Plug plug);\r
46 \r
47 struct plug_function_table {\r
48 void (*log)(Plug p, int type, SockAddr addr, int port,\r
49 const char *error_msg, int error_code);\r
50 /*\r
51 * Passes the client progress reports on the process of setting\r
52 * up the connection.\r
53 * \r
54 * - type==0 means we are about to try to connect to address\r
55 * `addr' (error_msg and error_code are ignored)\r
56 * - type==1 means we have failed to connect to address `addr'\r
57 * (error_msg and error_code are supplied). This is not a\r
58 * fatal error - we may well have other candidate addresses\r
59 * to fall back to. When it _is_ fatal, the closing()\r
60 * function will be called.\r
61 */\r
62 int (*closing)\r
63 (Plug p, const char *error_msg, int error_code, int calling_back);\r
64 /* error_msg is NULL iff it is not an error (ie it closed normally) */\r
65 /* calling_back != 0 iff there is a Plug function */\r
66 /* currently running (would cure the fixme in try_send()) */\r
67 int (*receive) (Plug p, int urgent, char *data, int len);\r
68 /*\r
69 * - urgent==0. `data' points to `len' bytes of perfectly\r
70 * ordinary data.\r
71 * \r
72 * - urgent==1. `data' points to `len' bytes of data,\r
73 * which were read from before an Urgent pointer.\r
74 * \r
75 * - urgent==2. `data' points to `len' bytes of data,\r
76 * the first of which was the one at the Urgent mark.\r
77 */\r
78 void (*sent) (Plug p, int bufsize);\r
79 /*\r
80 * The `sent' function is called when the pending send backlog\r
81 * on a socket is cleared or partially cleared. The new backlog\r
82 * size is passed in the `bufsize' parameter.\r
83 */\r
84 int (*accepting)(Plug p, accept_fn_t constructor, accept_ctx_t ctx);\r
85 /*\r
86 * `accepting' is called only on listener-type sockets, and is\r
87 * passed a constructor function+context that will create a fresh\r
88 * Socket describing the connection. It returns nonzero if it\r
89 * doesn't want the connection for some reason, or 0 on success.\r
90 */\r
91 };\r
92 \r
93 /* proxy indirection layer */\r
94 /* NB, control of 'addr' is passed via new_connection, which takes\r
95 * responsibility for freeing it */\r
96 Socket new_connection(SockAddr addr, char *hostname,\r
97 int port, int privport,\r
98 int oobinline, int nodelay, int keepalive,\r
99 Plug plug, Conf *conf);\r
100 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,\r
101 Conf *conf, int addressfamily);\r
102 SockAddr name_lookup(char *host, int port, char **canonicalname,\r
103 Conf *conf, int addressfamily);\r
104 int proxy_for_destination (SockAddr addr, const char *hostname, int port,\r
105 Conf *conf);\r
106 \r
107 /* platform-dependent callback from new_connection() */\r
108 /* (same caveat about addr as new_connection()) */\r
109 Socket platform_new_connection(SockAddr addr, char *hostname,\r
110 int port, int privport,\r
111 int oobinline, int nodelay, int keepalive,\r
112 Plug plug, Conf *conf);\r
113 \r
114 /* socket functions */\r
115 \r
116 void sk_init(void); /* called once at program startup */\r
117 void sk_cleanup(void); /* called just before program exit */\r
118 \r
119 SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);\r
120 SockAddr sk_nonamelookup(const char *host);\r
121 void sk_getaddr(SockAddr addr, char *buf, int buflen);\r
122 int sk_addr_needs_port(SockAddr addr);\r
123 int sk_hostname_is_local(const char *name);\r
124 int sk_address_is_local(SockAddr addr);\r
125 int sk_address_is_special_local(SockAddr addr);\r
126 int sk_addrtype(SockAddr addr);\r
127 void sk_addrcopy(SockAddr addr, char *buf);\r
128 void sk_addr_free(SockAddr addr);\r
129 /* sk_addr_dup generates another SockAddr which contains the same data\r
130 * as the original one and can be freed independently. May not actually\r
131 * physically _duplicate_ it: incrementing a reference count so that\r
132 * one more free is required before it disappears is an acceptable\r
133 * implementation. */\r
134 SockAddr sk_addr_dup(SockAddr addr);\r
135 \r
136 /* NB, control of 'addr' is passed via sk_new, which takes responsibility\r
137 * for freeing it, as for new_connection() */\r
138 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,\r
139 int nodelay, int keepalive, Plug p);\r
140 \r
141 Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only, int address_family);\r
142 \r
143 #define sk_plug(s,p) (((*s)->plug) (s, p))\r
144 #define sk_close(s) (((*s)->close) (s))\r
145 #define sk_write(s,buf,len) (((*s)->write) (s, buf, len))\r
146 #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))\r
147 #define sk_write_eof(s) (((*s)->write_eof) (s))\r
148 #define sk_flush(s) (((*s)->flush) (s))\r
149 \r
150 #ifdef DEFINE_PLUG_METHOD_MACROS\r
151 #define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))\r
152 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))\r
153 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))\r
154 #define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))\r
155 #define plug_accepting(p, constructor, ctx) (((*p)->accepting)(p, constructor, ctx))\r
156 #endif\r
157 \r
158 /*\r
159 * Special error values are returned from sk_namelookup and sk_new\r
160 * if there's a problem. These functions extract an error message,\r
161 * or return NULL if there's no problem.\r
162 */\r
163 const char *sk_addr_error(SockAddr addr);\r
164 #define sk_socket_error(s) (((*s)->socket_error) (s))\r
165 \r
166 /*\r
167 * Set the `frozen' flag on a socket. A frozen socket is one in\r
168 * which all READABLE notifications are ignored, so that data is\r
169 * not accepted from the peer until the socket is unfrozen. This\r
170 * exists for two purposes:\r
171 * \r
172 * - Port forwarding: when a local listening port receives a\r
173 * connection, we do not want to receive data from the new\r
174 * socket until we have somewhere to send it. Hence, we freeze\r
175 * the socket until its associated SSH channel is ready; then we\r
176 * unfreeze it and pending data is delivered.\r
177 * \r
178 * - Socket buffering: if an SSH channel (or the whole connection)\r
179 * backs up or presents a zero window, we must freeze the\r
180 * associated local socket in order to avoid unbounded buffer\r
181 * growth.\r
182 */\r
183 #define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))\r
184 \r
185 /*\r
186 * Return a (dynamically allocated) string giving some information\r
187 * about the other end of the socket, suitable for putting in log\r
188 * files. May be NULL if nothing is available at all.\r
189 */\r
190 #define sk_peer_info(s) (((*s)->peer_info) (s))\r
191 \r
192 /*\r
193 * Simple wrapper on getservbyname(), needed by ssh.c. Returns the\r
194 * port number, in host byte order (suitable for printf and so on).\r
195 * Returns 0 on failure. Any platform not supporting getservbyname\r
196 * can just return 0 - this function is not required to handle\r
197 * numeric port specifications.\r
198 */\r
199 int net_service_lookup(char *service);\r
200 \r
201 /*\r
202 * Look up the local hostname; return value needs freeing.\r
203 * May return NULL.\r
204 */\r
205 char *get_hostname(void);\r
206 \r
207 /*\r
208 * Trivial socket implementation which just stores an error. Found in\r
209 * errsock.c.\r
210 */\r
211 Socket new_error_socket(const char *errmsg, Plug plug);\r
212 \r
213 /********** SSL stuff **********/\r
214 \r
215 /*\r
216 * This section is subject to change, but you get the general idea\r
217 * of what it will eventually look like.\r
218 */\r
219 \r
220 typedef struct certificate *Certificate;\r
221 typedef struct our_certificate *Our_Certificate;\r
222 /* to be defined somewhere else, somehow */\r
223 \r
224 typedef struct ssl_client_socket_function_table **SSL_Client_Socket;\r
225 typedef struct ssl_client_plug_function_table **SSL_Client_Plug;\r
226 \r
227 struct ssl_client_socket_function_table {\r
228 struct socket_function_table base;\r
229 void (*renegotiate) (SSL_Client_Socket s);\r
230 /* renegotiate the cipher spec */\r
231 };\r
232 \r
233 struct ssl_client_plug_function_table {\r
234 struct plug_function_table base;\r
235 int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]);\r
236 /* do we accept this certificate chain? If not, why not? */\r
237 /* cert[0] is the server's certificate, cert[] is NULL-terminated */\r
238 /* the last certificate may or may not be the root certificate */\r
239 Our_Certificate(*client_cert) (SSL_Client_Plug p);\r
240 /* the server wants us to identify ourselves */\r
241 /* may return NULL if we want anonymity */\r
242 };\r
243 \r
244 SSL_Client_Socket sk_ssl_client_over(Socket s, /* pre-existing (tcp) connection */\r
245 SSL_Client_Plug p);\r
246 \r
247 #define sk_renegotiate(s) (((*s)->renegotiate) (s))\r
248 \r
249 #endif\r