2 * Networking abstraction in PuTTY.
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.
13 #ifndef PUTTY_NETWORK_H
14 #define PUTTY_NETWORK_H
16 typedef struct SockAddr_tag *SockAddr;
17 /* pay attention to levels of indirection */
18 typedef struct socket_function_table **Socket;
19 typedef struct plug_function_table **Plug;
21 struct socket_function_table {
22 Plug (*plug) (Socket s, Plug p);
23 /* use a different plug (return the old one) */
24 /* if p is NULL, it doesn't change the plug */
25 /* but it does return the one it's using */
26 void (*close) (Socket s);
27 void (*write) (Socket s, char *data, int len);
28 void (*write_oob) (Socket s, char *data, int len);
29 void (*flush) (Socket s);
30 /* ignored by tcp, but vital for ssl */
31 char *(*socket_error) (Socket s);
34 struct plug_function_table {
36 (Plug p, char *error_msg, int error_code, int calling_back);
37 /* error_msg is NULL iff it is not an error (ie it closed normally) */
38 /* calling_back != 0 iff there is a Plug function */
39 /* currently running (would cure the fixme in try_send()) */
40 int (*receive) (Plug p, int urgent, char *data, int len);
42 * - urgent==0. `data' points to `len' bytes of perfectly
45 * - urgent==1. `data' points to `len' bytes of data,
46 * which were read from before an Urgent pointer.
48 * - urgent==2. `data' points to `len' bytes of data,
49 * the first of which was the one at the Urgent mark.
54 void sk_init(void); /* called once at program startup */
56 SockAddr sk_namelookup(char *host, char **canonicalname);
57 void sk_addr_free(SockAddr addr);
59 Socket sk_new(SockAddr addr, int port, int privport, int oobinline, Plug p);
61 #define sk_plug(s,p) (((*s)->plug) (s, p))
62 #define sk_close(s) (((*s)->close) (s))
63 #define sk_write(s,buf,len) (((*s)->write) (s, buf, len))
64 #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))
65 #define sk_flush(s) (((*s)->flush) (s))
67 #ifdef DEFINE_PLUG_METHOD_MACROS
68 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))
69 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))
73 * Each socket abstraction contains a `void *' private field in
74 * which the client can keep state.
76 * This is perhaps unnecessary now that we have the notion of a plug,
77 * but there is some existing code that uses it, so it stays.
79 void sk_set_private_ptr(Socket s, void *ptr);
80 void *sk_get_private_ptr(Socket s);
83 * Special error values are returned from sk_namelookup and sk_new
84 * if there's a problem. These functions extract an error message,
85 * or return NULL if there's no problem.
87 char *sk_addr_error(SockAddr addr);
88 #define sk_socket_error(s) (((*s)->socket_error) (s))
91 /********** SSL stuff **********/
94 * This section is subject to change, but you get the general idea
95 * of what it will eventually look like.
99 typedef struct certificate *Certificate;
100 typedef struct our_certificate *Our_Certificate;
101 /* to be defined somewhere else, somehow */
103 typedef struct ssl_client_socket_function_table **SSL_Client_Socket;
104 typedef struct ssl_client_plug_function_table **SSL_Client_Plug;
106 struct ssl_client_socket_function_table {
107 struct socket_function_table base;
108 void (*renegotiate) (SSL_Client_Socket s);
109 /* renegotiate the cipher spec */
112 struct ssl_client_plug_function_table {
113 struct plug_function_table base;
114 int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]);
115 /* do we accept this certificate chain? If not, why not? */
116 /* cert[0] is the server's certificate, cert[] is NULL-terminated */
117 /* the last certificate may or may not be the root certificate */
118 Our_Certificate (*client_cert) (SSL_Client_Plug p);
119 /* the server wants us to identify ourselves */
120 /* may return NULL if we want anonymity */
123 SSL_Client_Socket sk_ssl_client_over (
124 Socket s, /* pre-existing (tcp) connection */
128 #define sk_renegotiate(s) (((*s)->renegotiate) (s))