2f75bae1 |
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. |
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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. |
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11 | */ |
12 | |
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13 | #ifndef PUTTY_NETWORK_H |
14 | #define PUTTY_NETWORK_H |
15 | |
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16 | #ifndef DONE_TYPEDEFS |
17 | #define DONE_TYPEDEFS |
18 | typedef struct config_tag Config; |
19 | typedef struct backend_tag Backend; |
20 | typedef struct terminal_tag Terminal; |
21 | #endif |
22 | |
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23 | typedef struct SockAddr_tag *SockAddr; |
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24 | /* pay attention to levels of indirection */ |
25 | typedef struct socket_function_table **Socket; |
26 | typedef struct plug_function_table **Plug; |
27 | |
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28 | #ifndef OSSOCKET_DEFINED |
29 | typedef void *OSSocket; |
30 | #endif |
31 | |
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32 | struct socket_function_table { |
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33 | Plug(*plug) (Socket s, Plug p); |
34 | /* use a different plug (return the old one) */ |
35 | /* if p is NULL, it doesn't change the plug */ |
36 | /* but it does return the one it's using */ |
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37 | void (*close) (Socket s); |
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38 | int (*write) (Socket s, const char *data, int len); |
39 | int (*write_oob) (Socket s, const char *data, int len); |
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40 | void (*flush) (Socket s); |
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41 | void (*set_private_ptr) (Socket s, void *ptr); |
42 | void *(*get_private_ptr) (Socket s); |
43 | void (*set_frozen) (Socket s, int is_frozen); |
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44 | /* ignored by tcp, but vital for ssl */ |
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45 | const char *(*socket_error) (Socket s); |
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46 | }; |
47 | |
48 | struct plug_function_table { |
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49 | void (*log)(Plug p, int type, SockAddr addr, int port, |
50 | const char *error_msg, int error_code); |
51 | /* |
52 | * Passes the client progress reports on the process of setting |
53 | * up the connection. |
54 | * |
55 | * - type==0 means we are about to try to connect to address |
56 | * `addr' (error_msg and error_code are ignored) |
57 | * - type==1 means we have failed to connect to address `addr' |
58 | * (error_msg and error_code are supplied). This is not a |
59 | * fatal error - we may well have other candidate addresses |
60 | * to fall back to. When it _is_ fatal, the closing() |
61 | * function will be called. |
62 | */ |
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63 | int (*closing) |
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64 | (Plug p, const char *error_msg, int error_code, int calling_back); |
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65 | /* error_msg is NULL iff it is not an error (ie it closed normally) */ |
66 | /* calling_back != 0 iff there is a Plug function */ |
67 | /* currently running (would cure the fixme in try_send()) */ |
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68 | int (*receive) (Plug p, int urgent, char *data, int len); |
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69 | /* |
70 | * - urgent==0. `data' points to `len' bytes of perfectly |
71 | * ordinary data. |
72 | * |
73 | * - urgent==1. `data' points to `len' bytes of data, |
74 | * which were read from before an Urgent pointer. |
75 | * |
76 | * - urgent==2. `data' points to `len' bytes of data, |
77 | * the first of which was the one at the Urgent mark. |
78 | */ |
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79 | void (*sent) (Plug p, int bufsize); |
80 | /* |
81 | * The `sent' function is called when the pending send backlog |
82 | * on a socket is cleared or partially cleared. The new backlog |
83 | * size is passed in the `bufsize' parameter. |
84 | */ |
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85 | int (*accepting)(Plug p, OSSocket sock); |
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86 | /* |
87 | * returns 0 if the host at address addr is a valid host for connecting or error |
88 | */ |
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89 | }; |
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90 | |
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91 | /* proxy indirection layer */ |
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92 | /* NB, control of 'addr' is passed via new_connection, which takes |
93 | * responsibility for freeing it */ |
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94 | Socket new_connection(SockAddr addr, char *hostname, |
95 | int port, int privport, |
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96 | int oobinline, int nodelay, int keepalive, |
97 | Plug plug, const Config *cfg); |
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98 | Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, |
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99 | const Config *cfg, int addressfamily); |
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100 | SockAddr name_lookup(char *host, int port, char **canonicalname, |
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101 | const Config *cfg, int addressfamily); |
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102 | |
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103 | /* platform-dependent callback from new_connection() */ |
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104 | /* (same caveat about addr as new_connection()) */ |
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105 | Socket platform_new_connection(SockAddr addr, char *hostname, |
106 | int port, int privport, |
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107 | int oobinline, int nodelay, int keepalive, |
108 | Plug plug, const Config *cfg); |
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109 | |
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110 | /* socket functions */ |
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111 | |
112 | void sk_init(void); /* called once at program startup */ |
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113 | void sk_cleanup(void); /* called just before program exit */ |
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114 | |
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115 | SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family); |
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116 | SockAddr sk_nonamelookup(const char *host); |
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117 | void sk_getaddr(SockAddr addr, char *buf, int buflen); |
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118 | int sk_hostname_is_local(char *name); |
119 | int sk_address_is_local(SockAddr addr); |
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120 | int sk_addrtype(SockAddr addr); |
121 | void sk_addrcopy(SockAddr addr, char *buf); |
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122 | void sk_addr_free(SockAddr addr); |
123 | |
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124 | /* NB, control of 'addr' is passed via sk_new, which takes responsibility |
125 | * for freeing it, as for new_connection() */ |
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126 | Socket sk_new(SockAddr addr, int port, int privport, int oobinline, |
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127 | int nodelay, int keepalive, Plug p); |
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128 | |
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129 | Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only, int address_family); |
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130 | |
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131 | Socket sk_register(OSSocket sock, Plug plug); |
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132 | |
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133 | #define sk_plug(s,p) (((*s)->plug) (s, p)) |
134 | #define sk_close(s) (((*s)->close) (s)) |
135 | #define sk_write(s,buf,len) (((*s)->write) (s, buf, len)) |
136 | #define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len)) |
137 | #define sk_flush(s) (((*s)->flush) (s)) |
138 | |
139 | #ifdef DEFINE_PLUG_METHOD_MACROS |
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140 | #define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code)) |
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141 | #define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback)) |
142 | #define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len)) |
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143 | #define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize)) |
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144 | #define plug_accepting(p, sock) (((*p)->accepting)(p, sock)) |
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145 | #endif |
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146 | |
147 | /* |
148 | * Each socket abstraction contains a `void *' private field in |
149 | * which the client can keep state. |
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150 | * |
151 | * This is perhaps unnecessary now that we have the notion of a plug, |
152 | * but there is some existing code that uses it, so it stays. |
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153 | */ |
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154 | #define sk_set_private_ptr(s, ptr) (((*s)->set_private_ptr) (s, ptr)) |
155 | #define sk_get_private_ptr(s) (((*s)->get_private_ptr) (s)) |
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156 | |
157 | /* |
158 | * Special error values are returned from sk_namelookup and sk_new |
159 | * if there's a problem. These functions extract an error message, |
160 | * or return NULL if there's no problem. |
161 | */ |
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162 | const char *sk_addr_error(SockAddr addr); |
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163 | #define sk_socket_error(s) (((*s)->socket_error) (s)) |
164 | |
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165 | /* |
166 | * Set the `frozen' flag on a socket. A frozen socket is one in |
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167 | * which all READABLE notifications are ignored, so that data is |
168 | * not accepted from the peer until the socket is unfrozen. This |
169 | * exists for two purposes: |
170 | * |
171 | * - Port forwarding: when a local listening port receives a |
172 | * connection, we do not want to receive data from the new |
173 | * socket until we have somewhere to send it. Hence, we freeze |
174 | * the socket until its associated SSH channel is ready; then we |
175 | * unfreeze it and pending data is delivered. |
176 | * |
177 | * - Socket buffering: if an SSH channel (or the whole connection) |
178 | * backs up or presents a zero window, we must freeze the |
179 | * associated local socket in order to avoid unbounded buffer |
180 | * growth. |
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181 | */ |
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182 | #define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen)) |
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183 | |
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184 | /* |
185 | * Call this after an operation that might have tried to send on a |
186 | * socket, to clean up any pending network errors. |
187 | */ |
188 | void net_pending_errors(void); |
189 | |
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190 | /* |
191 | * Simple wrapper on getservbyname(), needed by ssh.c. Returns the |
192 | * port number, in host byte order (suitable for printf and so on). |
193 | * Returns 0 on failure. Any platform not supporting getservbyname |
194 | * can just return 0 - this function is not required to handle |
195 | * numeric port specifications. |
196 | */ |
197 | int net_service_lookup(char *service); |
198 | |
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199 | /********** SSL stuff **********/ |
200 | |
201 | /* |
202 | * This section is subject to change, but you get the general idea |
203 | * of what it will eventually look like. |
204 | */ |
205 | |
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206 | typedef struct certificate *Certificate; |
207 | typedef struct our_certificate *Our_Certificate; |
208 | /* to be defined somewhere else, somehow */ |
209 | |
210 | typedef struct ssl_client_socket_function_table **SSL_Client_Socket; |
211 | typedef struct ssl_client_plug_function_table **SSL_Client_Plug; |
212 | |
213 | struct ssl_client_socket_function_table { |
214 | struct socket_function_table base; |
215 | void (*renegotiate) (SSL_Client_Socket s); |
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216 | /* renegotiate the cipher spec */ |
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217 | }; |
218 | |
219 | struct ssl_client_plug_function_table { |
220 | struct plug_function_table base; |
221 | int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]); |
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222 | /* do we accept this certificate chain? If not, why not? */ |
223 | /* cert[0] is the server's certificate, cert[] is NULL-terminated */ |
224 | /* the last certificate may or may not be the root certificate */ |
225 | Our_Certificate(*client_cert) (SSL_Client_Plug p); |
226 | /* the server wants us to identify ourselves */ |
227 | /* may return NULL if we want anonymity */ |
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228 | }; |
229 | |
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230 | SSL_Client_Socket sk_ssl_client_over(Socket s, /* pre-existing (tcp) connection */ |
231 | SSL_Client_Plug p); |
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232 | |
233 | #define sk_renegotiate(s) (((*s)->renegotiate) (s)) |
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234 | |
235 | #endif |