source: filezilla/trunk/fuentes/src/putty/network.h @ 130

Last change on this file since 130 was 130, checked in by jrpelegrina, 4 years ago

First release to xenial

File size: 9.6 KB
Line 
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
18typedef struct conf_tag Conf;
19typedef struct backend_tag Backend;
20typedef struct terminal_tag Terminal;
21#endif
22
23typedef struct SockAddr_tag *SockAddr;
24/* pay attention to levels of indirection */
25typedef struct socket_function_table **Socket;
26typedef struct plug_function_table **Plug;
27
28struct socket_function_table {
29    Plug(*plug) (Socket s, Plug p);
30    /* use a different plug (return the old one) */
31    /* if p is NULL, it doesn't change the plug */
32    /* but it does return the one it's using */
33    void (*close) (Socket s);
34    int (*write) (Socket s, const char *data, int len);
35    int (*write_oob) (Socket s, const char *data, int len);
36    void (*write_eof) (Socket s);
37    void (*flush) (Socket s);
38    void (*set_frozen) (Socket s, int is_frozen);
39    /* ignored by tcp, but vital for ssl */
40    const char *(*socket_error) (Socket s);
41    char *(*peer_info) (Socket s);
42};
43
44typedef union { void *p; int i; } accept_ctx_t;
45typedef Socket (*accept_fn_t)(accept_ctx_t ctx, Plug plug);
46
47struct plug_function_table {
48    void (*log)(Plug p, int type, SockAddr addr, int port,
49                const char *error_msg, int error_code);
50    /*
51     * Passes the client progress reports on the process of setting
52     * up the connection.
53     *
54     *  - type==0 means we are about to try to connect to address
55     *    `addr' (error_msg and error_code are ignored)
56     *  - type==1 means we have failed to connect to address `addr'
57     *    (error_msg and error_code are supplied). This is not a
58     *    fatal error - we may well have other candidate addresses
59     *    to fall back to. When it _is_ fatal, the closing()
60     *    function will be called.
61     */
62    int (*closing)
63     (Plug p, const char *error_msg, int error_code, int calling_back);
64    /* error_msg is NULL iff it is not an error (ie it closed normally) */
65    /* calling_back != 0 iff there is a Plug function */
66    /* currently running (would cure the fixme in try_send()) */
67    int (*receive) (Plug p, int urgent, char *data, int len);
68    /*
69     *  - urgent==0. `data' points to `len' bytes of perfectly
70     *    ordinary data.
71     *
72     *  - urgent==1. `data' points to `len' bytes of data,
73     *    which were read from before an Urgent pointer.
74     *
75     *  - urgent==2. `data' points to `len' bytes of data,
76     *    the first of which was the one at the Urgent mark.
77     */
78    void (*sent) (Plug p, int bufsize);
79    /*
80     * The `sent' function is called when the pending send backlog
81     * on a socket is cleared or partially cleared. The new backlog
82     * size is passed in the `bufsize' parameter.
83     */
84    int (*accepting)(Plug p, accept_fn_t constructor, accept_ctx_t ctx);
85    /*
86     * `accepting' is called only on listener-type sockets, and is
87     * passed a constructor function+context that will create a fresh
88     * Socket describing the connection. It returns nonzero if it
89     * doesn't want the connection for some reason, or 0 on success.
90     */
91};
92
93/* proxy indirection layer */
94/* NB, control of 'addr' is passed via new_connection, which takes
95 * responsibility for freeing it */
96Socket new_connection(SockAddr addr, const char *hostname,
97                      int port, int privport,
98                      int oobinline, int nodelay, int keepalive,
99                      Plug plug, Conf *conf);
100Socket new_listener(const char *srcaddr, int port, Plug plug,
101                    int local_host_only, Conf *conf, int addressfamily);
102SockAddr name_lookup(const char *host, int port, char **canonicalname,
103                     Conf *conf, int addressfamily);
104int proxy_for_destination (SockAddr addr, const char *hostname, int port,
105                           Conf *conf);
106
107/* platform-dependent callback from new_connection() */
108/* (same caveat about addr as new_connection()) */
109Socket platform_new_connection(SockAddr addr, const char *hostname,
110                               int port, int privport,
111                               int oobinline, int nodelay, int keepalive,
112                               Plug plug, Conf *conf);
113
114/* socket functions */
115
116void sk_init(void);                    /* called once at program startup */
117void sk_cleanup(void);                 /* called just before program exit */
118
119SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);
120SockAddr sk_nonamelookup(const char *host);
121void sk_getaddr(SockAddr addr, char *buf, int buflen);
122int sk_addr_needs_port(SockAddr addr);
123int sk_hostname_is_local(const char *name);
124int sk_address_is_local(SockAddr addr);
125int sk_address_is_special_local(SockAddr addr);
126int sk_addrtype(SockAddr addr);
127void sk_addrcopy(SockAddr addr, char *buf);
128void sk_addr_free(SockAddr addr);
129/* sk_addr_dup generates another SockAddr which contains the same data
130 * as the original one and can be freed independently. May not actually
131 * physically _duplicate_ it: incrementing a reference count so that
132 * one more free is required before it disappears is an acceptable
133 * implementation. */
134SockAddr sk_addr_dup(SockAddr addr);
135
136/* NB, control of 'addr' is passed via sk_new, which takes responsibility
137 * for freeing it, as for new_connection() */
138Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
139              int nodelay, int keepalive, Plug p);
140
141Socket sk_newlistener(const char *srcaddr, int port, Plug plug,
142                      int local_host_only, int address_family);
143
144#define sk_plug(s,p) (((*s)->plug) (s, p))
145#define sk_close(s) (((*s)->close) (s))
146#define sk_write(s,buf,len) (((*s)->write) (s, buf, len))
147#define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))
148#define sk_write_eof(s) (((*s)->write_eof) (s))
149#define sk_flush(s) (((*s)->flush) (s))
150
151#ifdef DEFINE_PLUG_METHOD_MACROS
152#define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))
153#define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))
154#define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))
155#define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))
156#define plug_accepting(p, constructor, ctx) (((*p)->accepting)(p, constructor, ctx))
157#endif
158
159/*
160 * Special error values are returned from sk_namelookup and sk_new
161 * if there's a problem. These functions extract an error message,
162 * or return NULL if there's no problem.
163 */
164const char *sk_addr_error(SockAddr addr);
165#define sk_socket_error(s) (((*s)->socket_error) (s))
166
167/*
168 * Set the `frozen' flag on a socket. A frozen socket is one in
169 * which all READABLE notifications are ignored, so that data is
170 * not accepted from the peer until the socket is unfrozen. This
171 * exists for two purposes:
172 *
173 *  - Port forwarding: when a local listening port receives a
174 *    connection, we do not want to receive data from the new
175 *    socket until we have somewhere to send it. Hence, we freeze
176 *    the socket until its associated SSH channel is ready; then we
177 *    unfreeze it and pending data is delivered.
178 *
179 *  - Socket buffering: if an SSH channel (or the whole connection)
180 *    backs up or presents a zero window, we must freeze the
181 *    associated local socket in order to avoid unbounded buffer
182 *    growth.
183 */
184#define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))
185
186/*
187 * Return a (dynamically allocated) string giving some information
188 * about the other end of the socket, suitable for putting in log
189 * files. May be NULL if nothing is available at all.
190 */
191#define sk_peer_info(s) (((*s)->peer_info) (s))
192
193/*
194 * Simple wrapper on getservbyname(), needed by ssh.c. Returns the
195 * port number, in host byte order (suitable for printf and so on).
196 * Returns 0 on failure. Any platform not supporting getservbyname
197 * can just return 0 - this function is not required to handle
198 * numeric port specifications.
199 */
200int net_service_lookup(char *service);
201
202/*
203 * Look up the local hostname; return value needs freeing.
204 * May return NULL.
205 */
206char *get_hostname(void);
207
208/*
209 * Trivial socket implementation which just stores an error. Found in
210 * errsock.c.
211 */
212Socket new_error_socket(const char *errmsg, Plug plug);
213
214/********** SSL stuff **********/
215
216/*
217 * This section is subject to change, but you get the general idea
218 * of what it will eventually look like.
219 */
220
221typedef struct certificate *Certificate;
222typedef struct our_certificate *Our_Certificate;
223    /* to be defined somewhere else, somehow */
224
225typedef struct ssl_client_socket_function_table **SSL_Client_Socket;
226typedef struct ssl_client_plug_function_table **SSL_Client_Plug;
227
228struct ssl_client_socket_function_table {
229    struct socket_function_table base;
230    void (*renegotiate) (SSL_Client_Socket s);
231    /* renegotiate the cipher spec */
232};
233
234struct ssl_client_plug_function_table {
235    struct plug_function_table base;
236    int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]);
237    /* do we accept this certificate chain?  If not, why not? */
238    /* cert[0] is the server's certificate, cert[] is NULL-terminated */
239    /* the last certificate may or may not be the root certificate */
240     Our_Certificate(*client_cert) (SSL_Client_Plug p);
241    /* the server wants us to identify ourselves */
242    /* may return NULL if we want anonymity */
243};
244
245SSL_Client_Socket sk_ssl_client_over(Socket s,  /* pre-existing (tcp) connection */
246                                     SSL_Client_Plug p);
247
248#define sk_renegotiate(s) (((*s)->renegotiate) (s))
249
250int recv_peek(Socket sk, char* buf, int len);
251
252#endif
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