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 function to be called when data comes in on
   7  * any given one, and it can call the networking abstraction to
   8  * send data without having to worry about blocking. The stuff
   9  * behind the abstraction takes care of selects and nonblocking
  10  * writes and all that sort of painful gubbins.
  11  *
  12  * If urgent data comes in on a socket, the back end will read and
  13  * discard up to the urgent pointer, then read the urgent byte and
  14  * send _that_ to the receiver function with `urgent' set.
  15  */
  16
  17 typedef struct Socket_tag *Socket;
  18 typedef struct SockAddr_tag *SockAddr;
  19 typedef int (*sk_receiver_t)(Socket s, int urgent, char *data, int len);
  20
  21 void sk_init(void);                    /* called once at program startup */
  22
  23 SockAddr sk_namelookup(char *host, char **canonicalname);
  24 void sk_addr_free(SockAddr addr);
  25
  26 Socket sk_new(SockAddr addr, int port, sk_receiver_t receiver);
  27 void sk_close(Socket s);
  28 void sk_write(Socket s, char *buf, int len);
  29 void sk_write_oob(Socket s, char *buf, int len);
  30
  31 /*
  32  * Each socket abstraction contains a `void *' private field in
  33  * which the client can keep state.
  34  */
  35 void sk_set_private_ptr(Socket s, void *ptr);
  36 void *sk_get_private_ptr(Socket s);
  37
  38 /*
  39  * Special error values are returned from sk_namelookup and sk_new
  40  * if there's a problem. These functions extract an error message,
  41  * or return NULL if there's no problem.
  42  */
  43 char *sk_addr_error(SockAddr addr);
  44 char *sk_socket_error(Socket addr);