source: filezilla/trunk/fuentes/src/putty/network.h @ 3185

Last change on this file since 3185 was 3185, checked in by jrpelegrina, 3 years ago

Update new version: 3.15.02

File size: 9.3 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     *  - type==2 means that error_msg contains a line of generic
62     *    logging information about setting up the connection. This
63     *    will typically be a wodge of standard-error output from a
64     *    proxy command, so the receiver should probably prefix it to
65     *    indicate this.
66     */
67    int (*closing)
68     (Plug p, const char *error_msg, int error_code, int calling_back);
69    /* error_msg is NULL iff it is not an error (ie it closed normally) */
70    /* calling_back != 0 iff there is a Plug function */
71    /* currently running (would cure the fixme in try_send()) */
72    int (*receive) (Plug p, int urgent, char *data, int len);
73    /*
74     *  - urgent==0. `data' points to `len' bytes of perfectly
75     *    ordinary data.
76     *
77     *  - urgent==1. `data' points to `len' bytes of data,
78     *    which were read from before an Urgent pointer.
79     *
80     *  - urgent==2. `data' points to `len' bytes of data,
81     *    the first of which was the one at the Urgent mark.
82     */
83    void (*sent) (Plug p, int bufsize);
84    /*
85     * The `sent' function is called when the pending send backlog
86     * on a socket is cleared or partially cleared. The new backlog
87     * size is passed in the `bufsize' parameter.
88     */
89    int (*accepting)(Plug p, accept_fn_t constructor, accept_ctx_t ctx);
90    /*
91     * `accepting' is called only on listener-type sockets, and is
92     * passed a constructor function+context that will create a fresh
93     * Socket describing the connection. It returns nonzero if it
94     * doesn't want the connection for some reason, or 0 on success.
95     */
96};
97
98/* proxy indirection layer */
99/* NB, control of 'addr' is passed via new_connection, which takes
100 * responsibility for freeing it */
101Socket new_connection(SockAddr addr, const char *hostname,
102                      int port, int privport,
103                      int oobinline, int nodelay, int keepalive,
104                      Plug plug, Conf *conf);
105Socket new_listener(const char *srcaddr, int port, Plug plug,
106                    int local_host_only, Conf *conf, int addressfamily);
107SockAddr name_lookup(const char *host, int port, char **canonicalname,
108                     Conf *conf, int addressfamily, void *frontend_for_logging,
109                     const char *lookup_reason_for_logging);
110int proxy_for_destination (SockAddr addr, const char *hostname, int port,
111                           Conf *conf);
112
113/* platform-dependent callback from new_connection() */
114/* (same caveat about addr as new_connection()) */
115Socket platform_new_connection(SockAddr addr, const char *hostname,
116                               int port, int privport,
117                               int oobinline, int nodelay, int keepalive,
118                               Plug plug, Conf *conf);
119
120/* socket functions */
121
122void sk_init(void);                    /* called once at program startup */
123void sk_cleanup(void);                 /* called just before program exit */
124
125SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family);
126SockAddr sk_nonamelookup(const char *host);
127void sk_getaddr(SockAddr addr, char *buf, int buflen);
128int sk_addr_needs_port(SockAddr addr);
129int sk_hostname_is_local(const char *name);
130int sk_address_is_local(SockAddr addr);
131int sk_address_is_special_local(SockAddr addr);
132int sk_addrtype(SockAddr addr);
133void sk_addrcopy(SockAddr addr, char *buf);
134void sk_addr_free(SockAddr addr);
135/* sk_addr_dup generates another SockAddr which contains the same data
136 * as the original one and can be freed independently. May not actually
137 * physically _duplicate_ it: incrementing a reference count so that
138 * one more free is required before it disappears is an acceptable
139 * implementation. */
140SockAddr sk_addr_dup(SockAddr addr);
141
142/* NB, control of 'addr' is passed via sk_new, which takes responsibility
143 * for freeing it, as for new_connection() */
144Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
145              int nodelay, int keepalive, Plug p);
146
147Socket sk_newlistener(const char *srcaddr, int port, Plug plug,
148                      int local_host_only, int address_family);
149
150#define sk_plug(s,p) (((*s)->plug) (s, p))
151#define sk_close(s) (((*s)->close) (s))
152#define sk_write(s,buf,len) (((*s)->write) (s, buf, len))
153#define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))
154#define sk_write_eof(s) (((*s)->write_eof) (s))
155#define sk_flush(s) (((*s)->flush) (s))
156
157#ifdef DEFINE_PLUG_METHOD_MACROS
158#define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code))
159#define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))
160#define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))
161#define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize))
162#define plug_accepting(p, constructor, ctx) (((*p)->accepting)(p, constructor, ctx))
163#endif
164
165/*
166 * Special error values are returned from sk_namelookup and sk_new
167 * if there's a problem. These functions extract an error message,
168 * or return NULL if there's no problem.
169 */
170const char *sk_addr_error(SockAddr addr);
171#define sk_socket_error(s) (((*s)->socket_error) (s))
172
173/*
174 * Set the `frozen' flag on a socket. A frozen socket is one in
175 * which all READABLE notifications are ignored, so that data is
176 * not accepted from the peer until the socket is unfrozen. This
177 * exists for two purposes:
178 *
179 *  - Port forwarding: when a local listening port receives a
180 *    connection, we do not want to receive data from the new
181 *    socket until we have somewhere to send it. Hence, we freeze
182 *    the socket until its associated SSH channel is ready; then we
183 *    unfreeze it and pending data is delivered.
184 *
185 *  - Socket buffering: if an SSH channel (or the whole connection)
186 *    backs up or presents a zero window, we must freeze the
187 *    associated local socket in order to avoid unbounded buffer
188 *    growth.
189 */
190#define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen))
191
192/*
193 * Return a (dynamically allocated) string giving some information
194 * about the other end of the socket, suitable for putting in log
195 * files. May be NULL if nothing is available at all.
196 */
197#define sk_peer_info(s) (((*s)->peer_info) (s))
198
199/*
200 * Simple wrapper on getservbyname(), needed by ssh.c. Returns the
201 * port number, in host byte order (suitable for printf and so on).
202 * Returns 0 on failure. Any platform not supporting getservbyname
203 * can just return 0 - this function is not required to handle
204 * numeric port specifications.
205 */
206int net_service_lookup(char *service);
207
208/*
209 * Look up the local hostname; return value needs freeing.
210 * May return NULL.
211 */
212char *get_hostname(void);
213
214/*
215 * Trivial socket implementation which just stores an error. Found in
216 * errsock.c.
217 */
218Socket new_error_socket(const char *errmsg, Plug plug);
219
220/* ----------------------------------------------------------------------
221 * Functions defined outside the network code, which have to be
222 * declared in this header file rather than the main putty.h because
223 * they use types defined here.
224 */
225
226/*
227 * Exports from be_misc.c.
228 */
229void backend_socket_log(void *frontend, int type, SockAddr addr, int port,
230                        const char *error_msg, int error_code, Conf *conf,
231                        int session_started);
232typedef struct bufchain_tag bufchain;  /* rest of declaration in misc.c */
233void log_proxy_stderr(Plug plug, bufchain *buf, const void *vdata, int len);
234
235#endif
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