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putty-source/sshbpp.h
Simon Tatham 93f2df9b83 New system for tracking data-limit-based rekeys.
I've removed the encrypted_len fields from PktIn and PktOut, which
were used to communicate from the BPP to ssh.c how much each packet
contributed to the amount of data encrypted with a given set of cipher
keys. It seems more sensible to have the BPP itself keep that counter
- especially since only one of the three BPPs even needs to count it
at all. So now there's a new DataTransferStats structure which the BPP
updates, and ssh.c only needs to check it for overflow and reset the
limits.
2018-09-19 23:08:28 +01:00

96 lines
3.5 KiB
C

/*
* Abstraction of the binary packet protocols used in SSH.
*/
#ifndef PUTTY_SSHBPP_H
#define PUTTY_SSHBPP_H
typedef struct BinaryPacketProtocol BinaryPacketProtocol;
struct BinaryPacketProtocolVtable {
void (*free)(BinaryPacketProtocol *);
void (*handle_input)(BinaryPacketProtocol *);
PktOut *(*new_pktout)(int type);
void (*format_packet)(BinaryPacketProtocol *, PktOut *);
};
struct BinaryPacketProtocol {
const struct BinaryPacketProtocolVtable *vt;
bufchain *in_raw, *out_raw;
PktInQueue *in_pq;
PacketLogSettings *pls;
LogContext *logctx;
int seen_disconnect;
char *error;
};
#define ssh_bpp_free(bpp) ((bpp)->vt->free(bpp))
#define ssh_bpp_handle_input(bpp) ((bpp)->vt->handle_input(bpp))
#define ssh_bpp_new_pktout(bpp, type) ((bpp)->vt->new_pktout(type))
#define ssh_bpp_format_packet(bpp, pkt) ((bpp)->vt->format_packet(bpp, pkt))
BinaryPacketProtocol *ssh1_bpp_new(void);
void ssh1_bpp_new_cipher(BinaryPacketProtocol *bpp,
const struct ssh1_cipheralg *cipher,
const void *session_key);
void ssh1_bpp_start_compression(BinaryPacketProtocol *bpp);
/*
* Structure that tracks how much data is sent and received, for
* purposes of triggering an SSH-2 rekey when either one gets over a
* configured limit. In each direction, the flag 'running' indicates
* that we haven't hit the limit yet, and 'remaining' tracks how much
* longer until we do. The macro DTS_CONSUME subtracts a given amount
* from the counter in a particular direction, and evaluates to a
* boolean indicating whether the limit has been hit.
*
* The limit is sticky: once 'running' has flipped to false,
* 'remaining' is no longer decremented, so it shouldn't dangerously
* wrap round.
*/
struct DataTransferStats {
struct {
int running;
unsigned long remaining;
} in, out;
};
#define DTS_CONSUME(stats, direction, size) \
((stats)->direction.running && \
(stats)->direction.remaining <= (size) ? \
((stats)->direction.running = FALSE, TRUE) : \
((stats)->direction.remaining -= (size), FALSE))
BinaryPacketProtocol *ssh2_bpp_new(struct DataTransferStats *stats);
void ssh2_bpp_new_outgoing_crypto(
BinaryPacketProtocol *bpp,
const struct ssh2_cipheralg *cipher, const void *ckey, const void *iv,
const struct ssh2_macalg *mac, int etm_mode, const void *mac_key,
const struct ssh_compression_alg *compression);
void ssh2_bpp_new_incoming_crypto(
BinaryPacketProtocol *bpp,
const struct ssh2_cipheralg *cipher, const void *ckey, const void *iv,
const struct ssh2_macalg *mac, int etm_mode, const void *mac_key,
const struct ssh_compression_alg *compression);
BinaryPacketProtocol *ssh2_bare_bpp_new(void);
/*
* The initial code to handle the SSH version exchange is also
* structured as an implementation of BinaryPacketProtocol, because
* that makes it easy to switch from that to the next BPP once it
* tells us which one we're using.
*/
struct ssh_version_receiver {
void (*got_ssh_version)(struct ssh_version_receiver *rcv,
int major_version);
};
BinaryPacketProtocol *ssh_verstring_new(
Conf *conf, Frontend *frontend, int bare_connection_mode,
const char *protoversion, struct ssh_version_receiver *rcv);
const char *ssh_verstring_get_remote(BinaryPacketProtocol *);
const char *ssh_verstring_get_local(BinaryPacketProtocol *);
int ssh_verstring_get_bugs(BinaryPacketProtocol *);
#endif /* PUTTY_SSHBPP_H */