git.distorted.org.uk Git - u/mdw/putty/blob - network.h

   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 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;
  20
  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);
  32 };
  33
  34 struct plug_function_table {
  35     int (*closing)
  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);
  41     /*
  42      *  - urgent==0. `data' points to `len' bytes of perfectly
  43      *    ordinary data.
  44      *
  45      *  - urgent==1. `data' points to `len' bytes of data,
  46      *    which were read from before an Urgent pointer.
  47      *
  48      *  - urgent==2. `data' points to `len' bytes of data,
  49      *    the first of which was the one at the Urgent mark.
  50      */
  51 };
  52
  53
  54 void sk_init(void);                    /* called once at program startup */
  55
  56 SockAddr sk_namelookup(char *host, char **canonicalname);
  57 void sk_addr_free(SockAddr addr);
  58
  59 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
  60               Plug p);
  61
  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))
  67
  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))
  71 #endif
  72
  73 /*
  74  * Each socket abstraction contains a `void *' private field in
  75  * which the client can keep state.
  76  *
  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.
  79  */
  80 void sk_set_private_ptr(Socket s, void *ptr);
  81 void *sk_get_private_ptr(Socket s);
  82
  83 /*
  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.
  87  */
  88 char *sk_addr_error(SockAddr addr);
  89 #define sk_socket_error(s) (((*s)->socket_error) (s))
  90
  91
  92 /********** SSL stuff **********/
  93
  94 /*
  95  * This section is subject to change, but you get the general idea
  96  * of what it will eventually look like.
  97  */
  98
  99
 100 typedef struct certificate *Certificate;
 101 typedef struct our_certificate *Our_Certificate;
 102     /* to be defined somewhere else, somehow */
 103
 104 typedef struct ssl_client_socket_function_table **SSL_Client_Socket;
 105 typedef struct ssl_client_plug_function_table **SSL_Client_Plug;
 106
 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 */
 111 };
 112
 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 */
 122 };
 123
 124 SSL_Client_Socket sk_ssl_client_over(Socket s,  /* pre-existing (tcp) connection */
 125                                      SSL_Client_Plug p);
 126
 127 #define sk_renegotiate(s) (((*s)->renegotiate) (s))
 128
 129 #endif