X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/2c94fd1cbf32093be173ea6c4378caa109f73dd4..edb548cd8283b5e3f680a0a8b641f9afb12d4ba4:/network.h diff --git a/network.h b/network.h index 528e92ab..49ebd39c 100644 --- a/network.h +++ b/network.h @@ -3,61 +3,248 @@ * * The way this works is: a back end can choose to open any number * of sockets - including zero, which might be necessary in some. - * It can register a function to be called when data comes in on - * any given one, and it can call the networking abstraction to - * send data without having to worry about blocking. The stuff - * behind the abstraction takes care of selects and nonblocking - * writes and all that sort of painful gubbins. + * It can register a bunch of callbacks (most notably for when + * data is received) for each socket, and it can call the networking + * abstraction to send data without having to worry about blocking. + * The stuff behind the abstraction takes care of selects and + * nonblocking writes and all that sort of painful gubbins. */ #ifndef PUTTY_NETWORK_H #define PUTTY_NETWORK_H -typedef struct Socket_tag *Socket; +#ifndef DONE_TYPEDEFS +#define DONE_TYPEDEFS +typedef struct conf_tag Conf; +typedef struct backend_tag Backend; +typedef struct terminal_tag Terminal; +#endif + typedef struct SockAddr_tag *SockAddr; +/* pay attention to levels of indirection */ +typedef struct socket_function_table **Socket; +typedef struct plug_function_table **Plug; -/* - * This is the function a client must register with each socket, to - * receive data coming in on that socket. The parameter `urgent' - * decides the meaning of `data' and `len': - * - * - urgent==0. `data' points to `len' bytes of perfectly ordinary - * data. - * - * - urgent==1. `data' points to `len' bytes of data, which were - * read from before an Urgent pointer. - * - * - urgent==2. `data' points to `len' bytes of data, the first of - * which was the one at the Urgent mark. - * - * - urgent==3. An error has occurred on the socket. `data' points - * to an error string, and `len' points to an error code. - */ -typedef int (*sk_receiver_t)(Socket s, int urgent, char *data, int len); +#ifndef OSSOCKET_DEFINED +typedef void *OSSocket; +#endif + +struct socket_function_table { + Plug(*plug) (Socket s, Plug p); + /* use a different plug (return the old one) */ + /* if p is NULL, it doesn't change the plug */ + /* but it does return the one it's using */ + void (*close) (Socket s); + int (*write) (Socket s, const char *data, int len); + int (*write_oob) (Socket s, const char *data, int len); + void (*write_eof) (Socket s); + void (*flush) (Socket s); + void (*set_private_ptr) (Socket s, void *ptr); + void *(*get_private_ptr) (Socket s); + void (*set_frozen) (Socket s, int is_frozen); + /* ignored by tcp, but vital for ssl */ + const char *(*socket_error) (Socket s); +}; + +struct plug_function_table { + void (*log)(Plug p, int type, SockAddr addr, int port, + const char *error_msg, int error_code); + /* + * Passes the client progress reports on the process of setting + * up the connection. + * + * - type==0 means we are about to try to connect to address + * `addr' (error_msg and error_code are ignored) + * - type==1 means we have failed to connect to address `addr' + * (error_msg and error_code are supplied). This is not a + * fatal error - we may well have other candidate addresses + * to fall back to. When it _is_ fatal, the closing() + * function will be called. + */ + int (*closing) + (Plug p, const char *error_msg, int error_code, int calling_back); + /* error_msg is NULL iff it is not an error (ie it closed normally) */ + /* calling_back != 0 iff there is a Plug function */ + /* currently running (would cure the fixme in try_send()) */ + int (*receive) (Plug p, int urgent, char *data, int len); + /* + * - urgent==0. `data' points to `len' bytes of perfectly + * ordinary data. + * + * - urgent==1. `data' points to `len' bytes of data, + * which were read from before an Urgent pointer. + * + * - urgent==2. `data' points to `len' bytes of data, + * the first of which was the one at the Urgent mark. + */ + void (*sent) (Plug p, int bufsize); + /* + * The `sent' function is called when the pending send backlog + * on a socket is cleared or partially cleared. The new backlog + * size is passed in the `bufsize' parameter. + */ + int (*accepting)(Plug p, OSSocket sock); + /* + * returns 0 if the host at address addr is a valid host for connecting or error + */ +}; + +/* proxy indirection layer */ +/* NB, control of 'addr' is passed via new_connection, which takes + * responsibility for freeing it */ +Socket new_connection(SockAddr addr, char *hostname, + int port, int privport, + int oobinline, int nodelay, int keepalive, + Plug plug, Conf *conf); +Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, + Conf *conf, int addressfamily); +SockAddr name_lookup(char *host, int port, char **canonicalname, + Conf *conf, int addressfamily); + +/* platform-dependent callback from new_connection() */ +/* (same caveat about addr as new_connection()) */ +Socket platform_new_connection(SockAddr addr, char *hostname, + int port, int privport, + int oobinline, int nodelay, int keepalive, + Plug plug, Conf *conf); + +/* socket functions */ void sk_init(void); /* called once at program startup */ +void sk_cleanup(void); /* called just before program exit */ -SockAddr sk_namelookup(char *host, char **canonicalname); +SockAddr sk_namelookup(const char *host, char **canonicalname, int address_family); +SockAddr sk_nonamelookup(const char *host); +void sk_getaddr(SockAddr addr, char *buf, int buflen); +int sk_hostname_is_local(char *name); +int sk_address_is_local(SockAddr addr); +int sk_address_is_special_local(SockAddr addr); +int sk_addrtype(SockAddr addr); +void sk_addrcopy(SockAddr addr, char *buf); void sk_addr_free(SockAddr addr); +/* sk_addr_dup generates another SockAddr which contains the same data + * as the original one and can be freed independently. May not actually + * physically _duplicate_ it: incrementing a reference count so that + * one more free is required before it disappears is an acceptable + * implementation. */ +SockAddr sk_addr_dup(SockAddr addr); + +/* NB, control of 'addr' is passed via sk_new, which takes responsibility + * for freeing it, as for new_connection() */ +Socket sk_new(SockAddr addr, int port, int privport, int oobinline, + int nodelay, int keepalive, Plug p); + +Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only, int address_family); + +Socket sk_register(OSSocket sock, Plug plug); -Socket sk_new(SockAddr addr, int port, int privport, sk_receiver_t receiver); -void sk_close(Socket s); -void sk_write(Socket s, char *buf, int len); -void sk_write_oob(Socket s, char *buf, int len); +#define sk_plug(s,p) (((*s)->plug) (s, p)) +#define sk_close(s) (((*s)->close) (s)) +#define sk_write(s,buf,len) (((*s)->write) (s, buf, len)) +#define sk_write_oob(s,buf,len) (((*s)->write_oob) (s, buf, len)) +#define sk_write_eof(s) (((*s)->write_eof) (s)) +#define sk_flush(s) (((*s)->flush) (s)) + +#ifdef DEFINE_PLUG_METHOD_MACROS +#define plug_log(p,type,addr,port,msg,code) (((*p)->log) (p, type, addr, port, msg, code)) +#define plug_closing(p,msg,code,callback) (((*p)->closing) (p, msg, code, callback)) +#define plug_receive(p,urgent,buf,len) (((*p)->receive) (p, urgent, buf, len)) +#define plug_sent(p,bufsize) (((*p)->sent) (p, bufsize)) +#define plug_accepting(p, sock) (((*p)->accepting)(p, sock)) +#endif /* * Each socket abstraction contains a `void *' private field in * which the client can keep state. + * + * This is perhaps unnecessary now that we have the notion of a plug, + * but there is some existing code that uses it, so it stays. */ -void sk_set_private_ptr(Socket s, void *ptr); -void *sk_get_private_ptr(Socket s); +#define sk_set_private_ptr(s, ptr) (((*s)->set_private_ptr) (s, ptr)) +#define sk_get_private_ptr(s) (((*s)->get_private_ptr) (s)) /* * Special error values are returned from sk_namelookup and sk_new * if there's a problem. These functions extract an error message, * or return NULL if there's no problem. */ -char *sk_addr_error(SockAddr addr); -char *sk_socket_error(Socket addr); +const char *sk_addr_error(SockAddr addr); +#define sk_socket_error(s) (((*s)->socket_error) (s)) + +/* + * Set the `frozen' flag on a socket. A frozen socket is one in + * which all READABLE notifications are ignored, so that data is + * not accepted from the peer until the socket is unfrozen. This + * exists for two purposes: + * + * - Port forwarding: when a local listening port receives a + * connection, we do not want to receive data from the new + * socket until we have somewhere to send it. Hence, we freeze + * the socket until its associated SSH channel is ready; then we + * unfreeze it and pending data is delivered. + * + * - Socket buffering: if an SSH channel (or the whole connection) + * backs up or presents a zero window, we must freeze the + * associated local socket in order to avoid unbounded buffer + * growth. + */ +#define sk_set_frozen(s, is_frozen) (((*s)->set_frozen) (s, is_frozen)) + +/* + * Call this after an operation that might have tried to send on a + * socket, to clean up any pending network errors. + */ +void net_pending_errors(void); + +/* + * Simple wrapper on getservbyname(), needed by ssh.c. Returns the + * port number, in host byte order (suitable for printf and so on). + * Returns 0 on failure. Any platform not supporting getservbyname + * can just return 0 - this function is not required to handle + * numeric port specifications. + */ +int net_service_lookup(char *service); + +/* + * Look up the local hostname; return value needs freeing. + * May return NULL. + */ +char *get_hostname(void); + +/********** SSL stuff **********/ + +/* + * This section is subject to change, but you get the general idea + * of what it will eventually look like. + */ + +typedef struct certificate *Certificate; +typedef struct our_certificate *Our_Certificate; + /* to be defined somewhere else, somehow */ + +typedef struct ssl_client_socket_function_table **SSL_Client_Socket; +typedef struct ssl_client_plug_function_table **SSL_Client_Plug; + +struct ssl_client_socket_function_table { + struct socket_function_table base; + void (*renegotiate) (SSL_Client_Socket s); + /* renegotiate the cipher spec */ +}; + +struct ssl_client_plug_function_table { + struct plug_function_table base; + int (*refuse_cert) (SSL_Client_Plug p, Certificate cert[]); + /* do we accept this certificate chain? If not, why not? */ + /* cert[0] is the server's certificate, cert[] is NULL-terminated */ + /* the last certificate may or may not be the root certificate */ + Our_Certificate(*client_cert) (SSL_Client_Plug p); + /* the server wants us to identify ourselves */ + /* may return NULL if we want anonymity */ +}; + +SSL_Client_Socket sk_ssl_client_over(Socket s, /* pre-existing (tcp) connection */ + SSL_Client_Plug p); + +#define sk_renegotiate(s) (((*s)->renegotiate) (s)) #endif