1
0
mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
putty-source/sshppl.h
Simon Tatham ad0c502cef Refactor the LogContext type.
LogContext is now the owner of the logevent() function that back ends
and so forth are constantly calling. Previously, logevent was owned by
the Frontend, which would store the message into its list for the GUI
Event Log dialog (or print it to standard error, or whatever) and then
pass it _back_ to LogContext to write to the currently open log file.
Now it's the other way round: LogContext gets the message from the
back end first, writes it to its log file if it feels so inclined, and
communicates it back to the front end.

This means that lots of parts of the back end system no longer need to
have a pointer to a full-on Frontend; the only thing they needed it
for was logging, so now they just have a LogContext (which many of
them had to have anyway, e.g. for logging SSH packets or session
traffic).

LogContext itself also doesn't get a full Frontend pointer any more:
it now talks back to the front end via a little vtable of its own
called LogPolicy, which contains the method that passes Event Log
entries through, the old askappend() function that decides whether to
truncate a pre-existing log file, and an emergency function for
printing an especially prominent message if the log file can't be
created. One minor nice effect of this is that console and GUI apps
can implement that last function subtly differently, so that Unix
console apps can write it with a plain \n instead of the \r\n
(harmless but inelegant) that the old centralised implementation
generated.

One other consequence of this is that the LogContext has to be
provided to backend_init() so that it's available to backends from the
instant of creation, rather than being provided via a separate API
call a couple of function calls later, because backends have typically
started doing things that need logging (like making network
connections) before the call to backend_provide_logctx. Fortunately,
there's no case in the whole code base where we don't already have
logctx by the time we make a backend (so I don't actually remember why
I ever delayed providing one). So that shortens the backend API by one
function, which is always nice.

While I'm tidying up, I've also moved the printf-style logeventf() and
the handy logevent_and_free() into logging.c, instead of having copies
of them scattered around other places. This has also let me remove
some stub functions from a couple of outlying applications like
Pageant. Finally, I've removed the pointless "_tag" at the end of
LogContext's official struct name.
2018-10-10 21:50:50 +01:00

146 lines
6.0 KiB
C

/*
* Abstraction of the various layers of SSH packet-level protocol,
* general enough to take in all three of the main SSH-2 layers and
* both of the SSH-1 phases.
*/
#ifndef PUTTY_SSHPPL_H
#define PUTTY_SSHPPL_H
typedef void (*packet_handler_fn_t)(PacketProtocolLayer *ppl, PktIn *pktin);
typedef void (*add_special_fn_t)(
void *ctx, const char *text, SessionSpecialCode code, int arg);
struct PacketProtocolLayerVtable {
void (*free)(PacketProtocolLayer *);
void (*process_queue)(PacketProtocolLayer *ppl);
int (*get_specials)(
PacketProtocolLayer *ppl, add_special_fn_t add_special, void *ctx);
void (*special_cmd)(
PacketProtocolLayer *ppl, SessionSpecialCode code, int arg);
int (*want_user_input)(PacketProtocolLayer *ppl);
void (*got_user_input)(PacketProtocolLayer *ppl);
void (*reconfigure)(PacketProtocolLayer *ppl, Conf *conf);
/* Protocol-level name of this layer. */
const char *name;
};
struct PacketProtocolLayer {
const struct PacketProtocolLayerVtable *vt;
/* Link to the underlying SSH BPP. */
BinaryPacketProtocol *bpp;
/* Queue from which the layer receives its input packets, and one
* to put its output packets on. */
PktInQueue *in_pq;
PktOutQueue *out_pq;
/* Idempotent callback that in_pq will be linked to, causing a
* call to the process_queue method. in_pq points to this, so it
* will be automatically triggered by pushing things on the
* layer's input queue, but it can also be triggered on purpose. */
IdempotentCallback ic_process_queue;
/* Owner's pointer to this layer. Permits a layer to unilaterally
* abdicate in favour of a replacement, by overwriting this
* pointer and then freeing itself. */
PacketProtocolLayer **selfptr;
/* Bufchain of keyboard input from the user, for login prompts and
* similar. */
bufchain *user_input;
/* Logging and error-reporting facilities. */
LogContext *logctx;
void *frontend; /* for dialog boxes etc */
Ssh *ssh; /* for session termination + assorted connection-layer ops */
/* Known bugs in the remote implementation. */
unsigned remote_bugs;
};
#define ssh_ppl_process_queue(ppl) ((ppl)->vt->process_queue(ppl))
#define ssh_ppl_get_specials(ppl, add, ctx) \
((ppl)->vt->get_specials(ppl, add, ctx))
#define ssh_ppl_special_cmd(ppl, code, arg) \
((ppl)->vt->special_cmd(ppl, code, arg))
#define ssh_ppl_want_user_input(ppl) ((ppl)->vt->want_user_input(ppl))
#define ssh_ppl_got_user_input(ppl) ((ppl)->vt->got_user_input(ppl))
#define ssh_ppl_reconfigure(ppl, conf) ((ppl)->vt->reconfigure(ppl, conf))
/* ssh_ppl_free is more than just a macro wrapper on the vtable; it
* does centralised parts of the freeing too. */
void ssh_ppl_free(PacketProtocolLayer *ppl);
/* Helper routine to point a PPL at its input and output queues. Also
* sets up the IdempotentCallback on the input queue to trigger a call
* to process_queue whenever packets are added to it. */
void ssh_ppl_setup_queues(PacketProtocolLayer *ppl,
PktInQueue *inq, PktOutQueue *outq);
/* Routine a PPL can call to abdicate in favour of a replacement, by
* overwriting ppl->selfptr. Has the side effect of freeing 'old', so
* if 'old' actually called this (which is likely) then it should
* avoid dereferencing itself on return from this function! */
void ssh_ppl_replace(PacketProtocolLayer *old, PacketProtocolLayer *new);
PacketProtocolLayer *ssh1_login_new(
Conf *conf, const char *host, int port,
PacketProtocolLayer *successor_layer);
PacketProtocolLayer *ssh1_connection_new(
Ssh *ssh, Conf *conf, ConnectionLayer **cl_out);
struct DataTransferStats;
struct ssh_connection_shared_gss_state;
PacketProtocolLayer *ssh2_transport_new(
Conf *conf, const char *host, int port, const char *fullhostname,
const char *client_greeting, const char *server_greeting,
struct ssh_connection_shared_gss_state *shgss,
struct DataTransferStats *stats,
PacketProtocolLayer *higher_layer);
PacketProtocolLayer *ssh2_userauth_new(
PacketProtocolLayer *successor_layer,
const char *hostname, const char *fullhostname,
Filename *keyfile, int tryagent,
const char *default_username, int change_username,
int try_ki_auth,
int try_gssapi_auth, int try_gssapi_kex_auth,
int gssapi_fwd, struct ssh_connection_shared_gss_state *shgss);
PacketProtocolLayer *ssh2_connection_new(
Ssh *ssh, ssh_sharing_state *connshare, int is_simple,
Conf *conf, const char *peer_verstring, ConnectionLayer **cl_out);
/* Can't put this in the userauth constructor without having a
* dependency loop at setup time (transport and userauth can't _both_
* be constructed second and given a pointer to the other). */
void ssh2_userauth_set_transport_layer(PacketProtocolLayer *userauth,
PacketProtocolLayer *transport);
/* Convenience macro for protocol layers to send formatted strings to
* the Event Log. Assumes a function parameter called 'ppl' is in
* scope, and takes a double pair of parens because it passes a whole
* argument list to dupprintf. */
#define ppl_logevent(params) ( \
logevent_and_free((ppl)->logctx, dupprintf params))
/* Convenience macro for protocol layers to send formatted strings to
* the terminal. Also expects 'ppl' to be in scope and takes double
* parens. */
#define ppl_printf(params) \
ssh_ppl_user_output_string_and_free(ppl, dupprintf params)
void ssh_ppl_user_output_string_and_free(PacketProtocolLayer *ppl, char *text);
/* Methods for userauth to communicate back to the transport layer */
ptrlen ssh2_transport_get_session_id(PacketProtocolLayer *ssh2_transport_ptr);
void ssh2_transport_notify_auth_done(PacketProtocolLayer *ssh2_transport_ptr);
/* Methods for ssh1login to pass protocol flags to ssh1connection */
void ssh1_connection_set_local_protoflags(PacketProtocolLayer *ppl, int flags);
/* Shared get_specials method between the two ssh1 layers */
int ssh1_common_get_specials(PacketProtocolLayer *, add_special_fn_t, void *);
#endif /* PUTTY_SSHPPL_H */