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1c1af145 | 1 | /* |
2 | * Networking abstraction in PuTTY. | |
3 | * | |
4 | * The way this works is: a back end can choose to open any number | |
5 | * of sockets - including zero, which might be necessary in some. | |
6 | * It can register a bunch of callbacks (most notably for when | |
7 | * data is received) for each socket, and it can call the networking | |
8 | * abstraction to send data without having to worry about blocking. | |
9 | * The stuff behind the abstraction takes care of selects and | |
10 | * nonblocking writes and all that sort of painful gubbins. | |
11 | */ | |
12 | ||
13 | #ifndef PUTTY_NETWORK_H | |
14 | #define PUTTY_NETWORK_H | |
15 | ||
16 | #ifndef DONE_TYPEDEFS | |
17 | #define DONE_TYPEDEFS | |
18 | typedef struct config_tag Config; | |
19 | typedef struct backend_tag Backend; | |
20 | typedef struct terminal_tag Terminal; | |
21 | #endif | |
22 | ||
23 | typedef struct SockAddr_tag *SockAddr; | |
24 | /* pay attention to levels of indirection */ | |
25 | typedef struct socket_function_table **Socket; | |
26 | typedef struct plug_function_table **Plug; | |
27 | ||
28 | #ifndef OSSOCKET_DEFINED | |
29 | typedef void *OSSocket; | |
30 | #endif | |
31 | ||
32 | struct socket_function_table { | |
33 | Plug(*plug) (Socket s, Plug p); | |
34 | /* use a different plug (return the old one) */ | |
35 | /* if p is NULL, it doesn't change the plug */ | |
36 | /* but it does return the one it's using */ | |
37 | void (*close) (Socket s); | |
38 | int (*write) (Socket s, const char *data, int len); | |
39 | int (*write_oob) (Socket s, const char *data, int len); | |
40 | void (*flush) (Socket s); | |
41 | void (*set_private_ptr) (Socket s, void *ptr); | |
42 | void *(*get_private_ptr) (Socket s); | |
43 | void (*set_frozen) (Socket s, int is_frozen); | |
44 | /* ignored by tcp, but vital for ssl */ | |
45 | const char *(*socket_error) (Socket s); | |
46 | }; | |
47 | ||
48 | struct plug_function_table { | |
49 | void (*log)(Plug p, int type, SockAddr addr, int port, | |
50 | const char *error_msg, int error_code); | |
51 | /* | |
52 | * Passes the client progress reports on the process of setting | |
53 | * up the connection. | |
54 | * | |
55 | * - type==0 means we are about to try to connect to address | |
56 | * `addr' (error_msg and error_code are ignored) | |
57 | * - type==1 means we have failed to connect to address `addr' | |
58 | * (error_msg and error_code are supplied). This is not a | |
59 | * fatal error - we may well have other candidate addresses | |
60 | * to fall back to. When it _is_ fatal, the closing() | |
61 | * function will be called. | |
62 | */ | |
63 | int (*closing) | |
64 | (Plug p, const char *error_msg, int error_code, int calling_back); | |
65 | /* error_msg is NULL iff it is not an error (ie it closed normally) */ | |
66 | /* calling_back != 0 iff there is a Plug function */ | |
67 | /* currently running (would cure the fixme in try_send()) */ | |
68 | int (*receive) (Plug p, int urgent, char *data, int len); | |
69 | /* | |
70 | * - urgent==0. `data' points to `len' bytes of perfectly | |
71 | * ordinary data. | |
72 | * | |
73 | * - urgent==1. `data' points to `len' bytes of data, | |
74 | * which were read from before an Urgent pointer. | |
75 | * | |
76 | * - urgent==2. `data' points to `len' bytes of data, | |
77 | * the first of which was the one at the Urgent mark. | |
78 | */ | |
79 | void (*sent) (Plug p, int bufsize); | |
80 | /* | |
81 | * The `sent' function is called when the pending send backlog | |
82 | * on a socket is cleared or partially cleared. The new backlog | |
83 | * size is passed in the `bufsize' parameter. | |
84 | */ | |
85 | int (*accepting)(Plug p, OSSocket sock); | |
86 | /* | |
87 | * returns 0 if the host at address addr is a valid host for connecting or error | |
88 | */ | |
89 | }; | |
90 | ||
91 | /* proxy indirection layer */ | |
92 | /* NB, control of 'addr' is passed via new_connection, which takes | |
93 | * responsibility for freeing it */ | |
94 | Socket new_connection(SockAddr addr, char *hostname, | |
95 | int port, int privport, | |
96 | int oobinline, int nodelay, int keepalive, | |
97 | Plug plug, const Config *cfg); | |
98 | Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, | |
99 | const Config *cfg, int addressfamily); | |
100 | SockAddr name_lookup(char *host, int port, char **canonicalname, | |
101 | const Config *cfg, int addressfamily); | |
102 | ||
103 | /* platform-dependent callback from new_connection() */ | |
104 | /* (same caveat about addr as new_connection()) */ | |
105 | Socket platform_new_connection(SockAddr addr, char *hostname, | |
106 | int port, int privport, | |
107 | int oobinline, int nodelay, int keepalive, | |
108 | Plug plug, const Config *cfg); | |
109 | ||
110 | /* socket functions */ | |
111 | ||
112 | void sk_init(void); /* called once at program startup */ | |
113 | void sk_cleanup(void); /* called just before program exit */ | |
114 | ||
115 | SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family); | |
116 | SockAddr sk_nonamelookup(const char *host); | |
117 | void sk_getaddr(SockAddr addr, char *buf, int buflen); | |
118 | int sk_hostname_is_local(char *name); | |
119 | int sk_address_is_local(SockAddr addr); | |
120 | int sk_addrtype(SockAddr addr); | |
121 | void sk_addrcopy(SockAddr addr, char *buf); | |
122 | void sk_addr_free(SockAddr addr); | |
123 | /* sk_addr_dup generates another SockAddr which contains the same data | |
124 | * as the original one and can be freed independently. May not actually | |
125 | * physically _duplicate_ it: incrementing a reference count so that | |
126 | * one more free is required before it disappears is an acceptable | |
127 | * implementation. */ | |
128 | SockAddr sk_addr_dup(SockAddr addr); | |
129 | ||
130 | /* NB, control of 'addr' is passed via sk_new, which takes responsibility | |
131 | * for freeing it, as for new_connection() */ | |
132 | Socket sk_new(SockAddr addr, int port, int privport, int oobinline, | |
133 | int nodelay, int keepalive, Plug p); | |
134 | ||
135 | Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only, int address_family); | |
136 | ||
137 | Socket sk_register(OSSocket sock, Plug plug); | |
138 | ||
139 | #define sk_plug(s,p) (((*s)->plug) (s, p)) | |
140 | #define sk_close(s) (((*s)->close) (s)) | |
141 | #define sk_write(s,buf,len) (((*s)->write) (s, buf, len)) | |
142 | #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len)) | |
143 | #define sk_flush(s) (((*s)->flush) (s)) | |
144 | ||
145 | #ifdef DEFINE_PLUG_METHOD_MACROS | |
146 | #define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code)) | |
147 | #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback)) | |
148 | #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len)) | |
149 | #define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize)) | |
150 | #define plug_accepting(p, sock) (((*p)->accepting)(p, sock)) | |
151 | #endif | |
152 | ||
153 | /* | |
154 | * Each socket abstraction contains a `void *' private field in | |
155 | * which the client can keep state. | |
156 | * | |
157 | * This is perhaps unnecessary now that we have the notion of a plug, | |
158 | * but there is some existing code that uses it, so it stays. | |
159 | */ | |
160 | #define sk_set_private_ptr(s, ptr) (((*s)->set_private_ptr) (s, ptr)) | |
161 | #define sk_get_private_ptr(s) (((*s)->get_private_ptr) (s)) | |
162 | ||
163 | /* | |
164 | * Special error values are returned from sk_namelookup and sk_new | |
165 | * if there's a problem. These functions extract an error message, | |
166 | * or return NULL if there's no problem. | |
167 | */ | |
168 | const char *sk_addr_error(SockAddr addr); | |
169 | #define sk_socket_error(s) (((*s)->socket_error) (s)) | |
170 | ||
171 | /* | |
172 | * Set the `frozen' flag on a socket. A frozen socket is one in | |
173 | * which all READABLE notifications are ignored, so that data is | |
174 | * not accepted from the peer until the socket is unfrozen. This | |
175 | * exists for two purposes: | |
176 | * | |
177 | * - Port forwarding: when a local listening port receives a | |
178 | * connection, we do not want to receive data from the new | |
179 | * socket until we have somewhere to send it. Hence, we freeze | |
180 | * the socket until its associated SSH channel is ready; then we | |
181 | * unfreeze it and pending data is delivered. | |
182 | * | |
183 | * - Socket buffering: if an SSH channel (or the whole connection) | |
184 | * backs up or presents a zero window, we must freeze the | |
185 | * associated local socket in order to avoid unbounded buffer | |
186 | * growth. | |
187 | */ | |
188 | #define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen)) | |
189 | ||
190 | /* | |
191 | * Call this after an operation that might have tried to send on a | |
192 | * socket, to clean up any pending network errors. | |
193 | */ | |
194 | void net_pending_errors(void); | |
195 | ||
196 | /* | |
197 | * Simple wrapper on getservbyname(), needed by ssh.c. Returns the | |
198 | * port number, in host byte order (suitable for printf and so on). | |
199 | * Returns 0 on failure. Any platform not supporting getservbyname | |
200 | * can just return 0 - this function is not required to handle | |
201 | * numeric port specifications. | |
202 | */ | |
203 | int net_service_lookup(char *service); | |
204 | ||
205 | /* | |
206 | * Look up the local hostname; return value needs freeing. | |
207 | * May return NULL. | |
208 | */ | |
209 | char *get_hostname(void); | |
210 | ||
211 | /********** SSL stuff **********/ | |
212 | ||
213 | /* | |
214 | * This section is subject to change, but you get the general idea | |
215 | * of what it will eventually look like. | |
216 | */ | |
217 | ||
218 | typedef struct certificate *Certificate; | |
219 | typedef struct our_certificate *Our_Certificate; | |
220 | /* to be defined somewhere else, somehow */ | |
221 | ||
222 | typedef struct ssl_client_socket_function_table **SSL_Client_Socket; | |
223 | typedef struct ssl_client_plug_function_table **SSL_Client_Plug; | |
224 | ||
225 | struct ssl_client_socket_function_table { | |
226 | struct socket_function_table base; | |
227 | void (*renegotiate) (SSL_Client_Socket s); | |
228 | /* renegotiate the cipher spec */ | |
229 | }; | |
230 | ||
231 | struct ssl_client_plug_function_table { | |
232 | struct plug_function_table base; | |
233 | int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]); | |
234 | /* do we accept this certificate chain? If not, why not? */ | |
235 | /* cert[0] is the server's certificate, cert[] is NULL-terminated */ | |
236 | /* the last certificate may or may not be the root certificate */ | |
237 | Our_Certificate(*client_cert) (SSL_Client_Plug p); | |
238 | /* the server wants us to identify ourselves */ | |
239 | /* may return NULL if we want anonymity */ | |
240 | }; | |
241 | ||
242 | SSL_Client_Socket sk_ssl_client_over(Socket s, /* pre-existing (tcp) connection */ | |
243 | SSL_Client_Plug p); | |
244 | ||
245 | #define sk_renegotiate(s) (((*s)->renegotiate) (s)) | |
246 | ||
247 | #endif |