| 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, Plug p); |
| 60 | |
| 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)) |
| 66 | |
| 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)) |
| 70 | #endif |
| 71 | |
| 72 | /* |
| 73 | * Each socket abstraction contains a `void *' private field in |
| 74 | * which the client can keep state. |
| 75 | * |
| 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. |
| 78 | */ |
| 79 | void sk_set_private_ptr(Socket s, void *ptr); |
| 80 | void *sk_get_private_ptr(Socket s); |
| 81 | |
| 82 | /* |
| 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. |
| 86 | */ |
| 87 | char *sk_addr_error(SockAddr addr); |
| 88 | #define sk_socket_error(s) (((*s)->socket_error) (s)) |
| 89 | |
| 90 | |
| 91 | /********** SSL stuff **********/ |
| 92 | |
| 93 | /* |
| 94 | * This section is subject to change, but you get the general idea |
| 95 | * of what it will eventually look like. |
| 96 | */ |
| 97 | |
| 98 | |
| 99 | typedef struct certificate *Certificate; |
| 100 | typedef struct our_certificate *Our_Certificate; |
| 101 | /* to be defined somewhere else, somehow */ |
| 102 | |
| 103 | typedef struct ssl_client_socket_function_table **SSL_Client_Socket; |
| 104 | typedef struct ssl_client_plug_function_table **SSL_Client_Plug; |
| 105 | |
| 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 */ |
| 110 | }; |
| 111 | |
| 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 */ |
| 121 | }; |
| 122 | |
| 123 | SSL_Client_Socket sk_ssl_client_over ( |
| 124 | Socket s, /* pre-existing (tcp) connection */ |
| 125 | SSL_Client_Plug p |
| 126 | ); |
| 127 | |
| 128 | #define sk_renegotiate(s) (((*s)->renegotiate) (s)) |
| 129 | |
| 130 | #endif |