зеркало из https://github.com/github/putty.git
285 строки
11 KiB
C
285 строки
11 KiB
C
/*
|
|
* Networking abstraction in PuTTY.
|
|
*
|
|
* 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 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
|
|
|
|
#include "defs.h"
|
|
|
|
typedef struct SocketVtable SocketVtable;
|
|
typedef struct PlugVtable PlugVtable;
|
|
|
|
struct Socket {
|
|
const struct SocketVtable *vt;
|
|
};
|
|
|
|
struct SocketVtable {
|
|
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 void *data, int len);
|
|
int (*write_oob) (Socket *s, const void *data, int len);
|
|
void (*write_eof) (Socket *s);
|
|
void (*flush) (Socket *s);
|
|
void (*set_frozen) (Socket *s, bool is_frozen);
|
|
/* ignored by tcp, but vital for ssl */
|
|
const char *(*socket_error) (Socket *s);
|
|
SocketPeerInfo *(*peer_info) (Socket *s);
|
|
};
|
|
|
|
typedef union { void *p; int i; } accept_ctx_t;
|
|
typedef Socket *(*accept_fn_t)(accept_ctx_t ctx, Plug *plug);
|
|
|
|
struct Plug {
|
|
const struct PlugVtable *vt;
|
|
};
|
|
|
|
struct PlugVtable {
|
|
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.
|
|
* - type==2 means that error_msg contains a line of generic
|
|
* logging information about setting up the connection. This
|
|
* will typically be a wodge of standard-error output from a
|
|
* proxy command, so the receiver should probably prefix it to
|
|
* indicate this.
|
|
*/
|
|
void (*closing)
|
|
(Plug *p, const char *error_msg, int error_code, bool 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()) */
|
|
void (*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, accept_fn_t constructor, accept_ctx_t ctx);
|
|
/*
|
|
* `accepting' is called only on listener-type sockets, and is
|
|
* passed a constructor function+context that will create a fresh
|
|
* Socket describing the connection. It returns nonzero if it
|
|
* doesn't want the connection for some reason, or 0 on success.
|
|
*/
|
|
};
|
|
|
|
/* proxy indirection layer */
|
|
/* NB, control of 'addr' is passed via new_connection, which takes
|
|
* responsibility for freeing it */
|
|
Socket *new_connection(SockAddr *addr, const char *hostname,
|
|
int port, bool privport,
|
|
bool oobinline, bool nodelay, bool keepalive,
|
|
Plug *plug, Conf *conf);
|
|
Socket *new_listener(const char *srcaddr, int port, Plug *plug,
|
|
bool local_host_only, Conf *conf, int addressfamily);
|
|
SockAddr *name_lookup(const char *host, int port, char **canonicalname,
|
|
Conf *conf, int addressfamily, LogContext *logctx,
|
|
const char *lookup_reason_for_logging);
|
|
bool proxy_for_destination (SockAddr *addr, const char *hostname, int port,
|
|
Conf *conf);
|
|
|
|
/* platform-dependent callback from new_connection() */
|
|
/* (same caveat about addr as new_connection()) */
|
|
Socket *platform_new_connection(SockAddr *addr, const char *hostname,
|
|
int port, bool privport,
|
|
bool oobinline, bool nodelay, bool 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(const char *host, char **canonicalname, int address_family);
|
|
SockAddr *sk_nonamelookup(const char *host);
|
|
void sk_getaddr(SockAddr *addr, char *buf, int buflen);
|
|
bool sk_addr_needs_port(SockAddr *addr);
|
|
bool sk_hostname_is_local(const char *name);
|
|
bool sk_address_is_local(SockAddr *addr);
|
|
bool 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, bool privport, bool oobinline,
|
|
bool nodelay, bool keepalive, Plug *p);
|
|
|
|
Socket *sk_newlistener(const char *srcaddr, int port, Plug *plug,
|
|
bool local_host_only, int address_family);
|
|
|
|
#define sk_plug(s,p) (((s)->vt->plug) (s, p))
|
|
#define sk_close(s) (((s)->vt->close) (s))
|
|
#define sk_write(s,buf,len) (((s)->vt->write) (s, buf, len))
|
|
#define sk_write_oob(s,buf,len) (((s)->vt->write_oob) (s, buf, len))
|
|
#define sk_write_eof(s) (((s)->vt->write_eof) (s))
|
|
#define sk_flush(s) (((s)->vt->flush) (s))
|
|
|
|
#define plug_log(p,type,addr,port,msg,code) \
|
|
(((p)->vt->log) (p, type, addr, port, msg, code))
|
|
#define plug_closing(p,msg,code,callback) \
|
|
(((p)->vt->closing) (p, msg, code, callback))
|
|
#define plug_receive(p,urgent,buf,len) \
|
|
(((p)->vt->receive) (p, urgent, buf, len))
|
|
#define plug_sent(p,bufsize) \
|
|
(((p)->vt->sent) (p, bufsize))
|
|
#define plug_accepting(p, constructor, ctx) \
|
|
(((p)->vt->accepting)(p, constructor, ctx))
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
const char *sk_addr_error(SockAddr *addr);
|
|
#define sk_socket_error(s) (((s)->vt->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)->vt->set_frozen) (s, is_frozen))
|
|
|
|
/*
|
|
* Return a structure giving some information about the other end of
|
|
* the socket. May be NULL, if nothing is available at all. If it is
|
|
* not NULL, then it is dynamically allocated, and should be freed by
|
|
* a call to sk_free_peer_info(). See below for the definition.
|
|
*/
|
|
#define sk_peer_info(s) (((s)->vt->peer_info) (s))
|
|
|
|
/*
|
|
* The structure returned from sk_peer_info, and a function to free
|
|
* one (in misc.c).
|
|
*/
|
|
struct SocketPeerInfo {
|
|
int addressfamily;
|
|
|
|
/*
|
|
* Text form of the IPv4 or IPv6 address of the other end of the
|
|
* socket, if available, in the standard text representation.
|
|
*/
|
|
const char *addr_text;
|
|
|
|
/*
|
|
* Binary form of the same address. Filled in if and only if
|
|
* addr_text is not NULL. You can tell which branch of the union
|
|
* is used by examining 'addressfamily'.
|
|
*/
|
|
union {
|
|
unsigned char ipv6[16];
|
|
unsigned char ipv4[4];
|
|
} addr_bin;
|
|
|
|
/*
|
|
* Remote port number, or -1 if not available.
|
|
*/
|
|
int port;
|
|
|
|
/*
|
|
* Free-form text suitable for putting in log messages. For IP
|
|
* sockets, repeats the address and port information from above.
|
|
* But it can be completely different, e.g. for Unix-domain
|
|
* sockets it gives information about the uid, gid and pid of the
|
|
* connecting process.
|
|
*/
|
|
const char *log_text;
|
|
};
|
|
void sk_free_peer_info(SocketPeerInfo *pi);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* Trivial socket implementation which just stores an error. Found in
|
|
* errsock.c.
|
|
*/
|
|
Socket *new_error_socket_fmt(Plug *plug, const char *fmt, ...);
|
|
|
|
/*
|
|
* Trivial plug that does absolutely nothing. Found in nullplug.c.
|
|
*/
|
|
extern Plug *const nullplug;
|
|
|
|
/* ----------------------------------------------------------------------
|
|
* Functions defined outside the network code, which have to be
|
|
* declared in this header file rather than the main putty.h because
|
|
* they use types defined here.
|
|
*/
|
|
|
|
/*
|
|
* Exports from be_misc.c.
|
|
*/
|
|
void backend_socket_log(Seat *seat, LogContext *logctx,
|
|
int type, SockAddr *addr, int port,
|
|
const char *error_msg, int error_code, Conf *conf,
|
|
bool session_started);
|
|
void log_proxy_stderr(Plug *plug, bufchain *buf, const void *vdata, int len);
|
|
|
|
#endif
|