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
,
62 #define sk_plug(s,p) (((*s)->plug) (s, p))
63 #define sk_close(s) (((*s)->close) (s))
64 #define sk_write(s,buf,len) (((*s)->write) (s, buf, len))
65 #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len))
66 #define sk_flush(s) (((*s)->flush) (s))
68 #ifdef DEFINE_PLUG_METHOD_MACROS
69 #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback))
70 #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len))
74 * Each socket abstraction contains a `void *' private field in
75 * which the client can keep state.
77 * This is perhaps unnecessary now that we have the notion of a plug,
78 * but there is some existing code that uses it, so it stays.
80 void sk_set_private_ptr(Socket s
, void *ptr
);
81 void *sk_get_private_ptr(Socket s
);
84 * Special error values are returned from sk_namelookup and sk_new
85 * if there's a problem. These functions extract an error message,
86 * or return NULL if there's no problem.
88 char *sk_addr_error(SockAddr addr
);
89 #define sk_socket_error(s) (((*s)->socket_error) (s))
92 /********** SSL stuff **********/
95 * This section is subject to change, but you get the general idea
96 * of what it will eventually look like.
100 typedef struct certificate
*Certificate
;
101 typedef struct our_certificate
*Our_Certificate
;
102 /* to be defined somewhere else, somehow */
104 typedef struct ssl_client_socket_function_table
**SSL_Client_Socket
;
105 typedef struct ssl_client_plug_function_table
**SSL_Client_Plug
;
107 struct ssl_client_socket_function_table
{
108 struct socket_function_table base
;
109 void (*renegotiate
) (SSL_Client_Socket s
);
110 /* renegotiate the cipher spec */
113 struct ssl_client_plug_function_table
{
114 struct plug_function_table base
;
115 int (*refuse_cert
) (SSL_Client_Plug p
, Certificate cert
[]);
116 /* do we accept this certificate chain? If not, why not? */
117 /* cert[0] is the server's certificate, cert[] is NULL-terminated */
118 /* the last certificate may or may not be the root certificate */
119 Our_Certificate(*client_cert
) (SSL_Client_Plug p
);
120 /* the server wants us to identify ourselves */
121 /* may return NULL if we want anonymity */
124 SSL_Client_Socket
sk_ssl_client_over(Socket s
, /* pre-existing (tcp) connection */
127 #define sk_renegotiate(s) (((*s)->renegotiate) (s))