| blob | 624e58be627423f93bc7e77ff38a4498eb1bb818 |
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 * - type==2 means that error_msg contains a line of generic\r
62 * logging information about setting up the connection. This\r
63 * will typically be a wodge of standard-error output from a\r
64 * proxy command, so the receiver should probably prefix it to\r
65 * indicate this.\r
66 */\r
67 int (*closing)\r
68 (Plug p, const char *error_msg, int error_code, int calling_back);\r
69 /* error_msg is NULL iff it is not an error (ie it closed normally) */\r
70 /* calling_back != 0 iff there is a Plug function */\r
71 /* currently running (would cure the fixme in try_send()) */\r
72 int (*receive) (Plug p, int urgent, char *data, int len);\r
73 /*\r
74 * - urgent==0. `data' points to `len' bytes of perfectly\r
75 * ordinary data.\r
76 * \r
77 * - urgent==1. `data' points to `len' bytes of data,\r
78 * which were read from before an Urgent pointer.\r
79 * \r
80 * - urgent==2. `data' points to `len' bytes of data,\r
81 * the first of which was the one at the Urgent mark.\r
82 */\r
83 void (*sent) (Plug p, int bufsize);\r
84 /*\r
85 * The `sent' function is called when the pending send backlog\r
86 * on a socket is cleared or partially cleared. The new backlog\r
87 * size is passed in the `bufsize' parameter.\r
88 */\r
89 int (*accepting)(Plug p, accept_fn_t constructor, accept_ctx_t ctx);\r
90 /*\r
91 * `accepting' is called only on listener-type sockets, and is\r
92 * passed a constructor function+context that will create a fresh\r
93 * Socket describing the connection. It returns nonzero if it\r
94 * doesn't want the connection for some reason, or 0 on success.\r
95 */\r
96 };\r
97 \r
98 /* proxy indirection layer */\r
99 /* NB, control of 'addr' is passed via new_connection, which takes\r
100 * responsibility for freeing it */\r
101 Socket new_connection(SockAddr addr, const char *hostname,\r
102 int port, int privport,\r
103 int oobinline, int nodelay, int keepalive,\r
104 Plug plug, Conf *conf);\r
105 Socket new_listener(const char *srcaddr, int port, Plug plug,\r
106 int local_host_only, Conf *conf, int addressfamily);\r
107 SockAddr name_lookup(const char *host, int port, char **canonicalname,\r
108 Conf *conf, int addressfamily, void *frontend_for_logging,\r
109 const char *lookup_reason_for_logging);\r
110 int proxy_for_destination (SockAddr addr, const char *hostname, int port,\r
111 Conf *conf);\r
112 \r
113 /* platform-dependent callback from new_connection() */\r
114 /* (same caveat about addr as new_connection()) */\r
115 Socket platform_new_connection(SockAddr addr, const char *hostname,\r
116 int port, int privport,\r
117 int oobinline, int nodelay, int keepalive,\r
118 Plug plug, Conf *conf);\r
119 \r
120 /* socket functions */\r
121 \r
122 void sk_init(void); /* called once at program startup */\r
123 void sk_cleanup(void); /* called just before program exit */\r
124 \r
125 SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);\r
126 SockAddr sk_nonamelookup(const char *host);\r
127 void sk_getaddr(SockAddr addr, char *buf, int buflen);\r
128 int sk_addr_needs_port(SockAddr addr);\r
129 int sk_hostname_is_local(const char *name);\r
130 int sk_address_is_local(SockAddr addr);\r
131 int sk_address_is_special_local(SockAddr addr);\r
132 int sk_addrtype(SockAddr addr);\r
133 void sk_addrcopy(SockAddr addr, char *buf);\r
134 void sk_addr_free(SockAddr addr);\r
135 /* sk_addr_dup generates another SockAddr which contains the same data\r
136 * as the original one and can be freed independently. May not actually\r
137 * physically _duplicate_ it: incrementing a reference count so that\r
138 * one more free is required before it disappears is an acceptable\r
139 * implementation. */\r
140 SockAddr sk_addr_dup(SockAddr addr);\r
141 \r
142 /* NB, control of 'addr' is passed via sk_new, which takes responsibility\r
143 * for freeing it, as for new_connection() */\r
144 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,\r
145 int nodelay, int keepalive, Plug p);\r
146 \r
147 Socket sk_newlistener(const char *srcaddr, int port, Plug plug,\r
148 int local_host_only, int address_family);\r
149 \r
150 #define sk_plug(s,p) (((*s)->plug) (s, p))\r
151 #define sk_close(s) (((*s)->close) (s))\r
152 #define sk_write(s,buf,len) (((*s)->write) (s, buf, len))\r
153 #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))\r
154 #define sk_write_eof(s) (((*s)->write_eof) (s))\r
155 #define sk_flush(s) (((*s)->flush) (s))\r
156 \r
157 #ifdef DEFINE_PLUG_METHOD_MACROS\r
158 #define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))\r
159 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))\r
160 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))\r
161 #define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))\r
162 #define plug_accepting(p, constructor, ctx) (((*p)->accepting)(p, constructor, ctx))\r
163 #endif\r
164 \r
165 /*\r
166 * Special error values are returned from sk_namelookup and sk_new\r
167 * if there's a problem. These functions extract an error message,\r
168 * or return NULL if there's no problem.\r
169 */\r
170 const char *sk_addr_error(SockAddr addr);\r
171 #define sk_socket_error(s) (((*s)->socket_error) (s))\r
172 \r
173 /*\r
174 * Set the `frozen' flag on a socket. A frozen socket is one in\r
175 * which all READABLE notifications are ignored, so that data is\r
176 * not accepted from the peer until the socket is unfrozen. This\r
177 * exists for two purposes:\r
178 * \r
179 * - Port forwarding: when a local listening port receives a\r
180 * connection, we do not want to receive data from the new\r
181 * socket until we have somewhere to send it. Hence, we freeze\r
182 * the socket until its associated SSH channel is ready; then we\r
183 * unfreeze it and pending data is delivered.\r
184 * \r
185 * - Socket buffering: if an SSH channel (or the whole connection)\r
186 * backs up or presents a zero window, we must freeze the\r
187 * associated local socket in order to avoid unbounded buffer\r
188 * growth.\r
189 */\r
190 #define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))\r
191 \r
192 /*\r
193 * Return a (dynamically allocated) string giving some information\r
194 * about the other end of the socket, suitable for putting in log\r
195 * files. May be NULL if nothing is available at all.\r
196 */\r
197 #define sk_peer_info(s) (((*s)->peer_info) (s))\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 /*\r
215 * Trivial socket implementation which just stores an error. Found in\r
216 * errsock.c.\r
217 */\r
218 Socket new_error_socket(const char *errmsg, Plug plug);\r
219 \r
220 /* ----------------------------------------------------------------------\r
221 * Functions defined outside the network code, which have to be\r
222 * declared in this header file rather than the main putty.h because\r
223 * they use types defined here.\r
224 */\r
225 \r
226 /*\r
227 * Exports from be_misc.c.\r
228 */\r
229 void backend_socket_log(void *frontend, int type, SockAddr addr, int port,\r
230 const char *error_msg, int error_code, Conf *conf,\r
231 int session_started);\r
232 #ifndef BUFCHAIN_TYPEDEF\r
233 typedef struct bufchain_tag bufchain; /* rest of declaration in misc.c */\r
234 #define BUFCHAIN_TYPEDEF\r
235 #endif\r
236 void log_proxy_stderr(Plug plug, bufchain *buf, const void *vdata, int len);\r
237 \r
238 #endif\r