[u/mdw/putty] / ssh.h

#include <string.h>

#include "puttymem.h"

/*
 * Useful thing.
 */
#ifndef lenof
#define lenof(x) ( (sizeof((x))) / (sizeof(*(x))))
#endif

#define SSH_CIPHER_IDEA		1
#define SSH_CIPHER_DES		2
#define SSH_CIPHER_3DES		3
#define SSH_CIPHER_BLOWFISH	6

#ifdef MSCRYPTOAPI
#define APIEXTRA 8
#else
#define APIEXTRA 0
#endif

#ifndef BIGNUM_INTERNAL
typedef void *Bignum;
#endif

struct RSAKey {
    int bits;
    int bytes;
#ifdef MSCRYPTOAPI
    unsigned long exponent;
    unsigned char *modulus;
#else
    Bignum modulus;
    Bignum exponent;
    Bignum private_exponent;
    Bignum p;
    Bignum q;
    Bignum iqmp;
#endif
    char *comment;
};

int makekey(unsigned char *data, struct RSAKey *result,
	    unsigned char **keystr, int order);
int makeprivate(unsigned char *data, struct RSAKey *result);
void rsaencrypt(unsigned char *data, int length, struct RSAKey *key);
Bignum rsadecrypt(Bignum input, struct RSAKey *key);
void rsasign(unsigned char *data, int length, struct RSAKey *key);
void rsasanitise(struct RSAKey *key);
int rsastr_len(struct RSAKey *key);
void rsastr_fmt(char *str, struct RSAKey *key);
void rsa_fingerprint(char *str, int len, struct RSAKey *key);
int rsa_verify(struct RSAKey *key);
void freersakey(struct RSAKey *key);

typedef unsigned int word32;
typedef unsigned int uint32;

unsigned long crc32(const void *s, size_t len);

typedef struct {
    uint32 h[4];
} MD5_Core_State;

struct MD5Context {
#ifdef MSCRYPTOAPI
    unsigned long hHash;
#else
    MD5_Core_State core;
    unsigned char block[64];
    int blkused;
    uint32 lenhi, lenlo;
#endif
};

void MD5Init(struct MD5Context *context);
void MD5Update(struct MD5Context *context, unsigned char const *buf,
	       unsigned len);
void MD5Final(unsigned char digest[16], struct MD5Context *context);

typedef struct {
    uint32 h[5];
    unsigned char block[64];
    int blkused;
    uint32 lenhi, lenlo;
} SHA_State;

void SHA_Init(SHA_State * s);
void SHA_Bytes(SHA_State * s, void *p, int len);
void SHA_Final(SHA_State * s, unsigned char *output);
void SHA_Simple(void *p, int len, unsigned char *output);

struct ssh_cipher {
    void (*sesskey) (unsigned char *key);	/* for ssh 1 */
    void (*encrypt) (unsigned char *blk, int len);
    void (*decrypt) (unsigned char *blk, int len);
    int blksize;
};

struct ssh2_cipher {
    void (*setcsiv) (unsigned char *key);	/* for ssh 2 */
    void (*setcskey) (unsigned char *key);	/* for ssh 2 */
    void (*setsciv) (unsigned char *key);	/* for ssh 2 */
    void (*setsckey) (unsigned char *key);	/* for ssh 2 */
    void (*encrypt) (unsigned char *blk, int len);
    void (*decrypt) (unsigned char *blk, int len);
    char *name;
    int blksize;
    int keylen;
};

struct ssh2_ciphers {
    int nciphers;
    const struct ssh2_cipher *const *list;
};

struct ssh_mac {
    void (*setcskey) (unsigned char *key);
    void (*setsckey) (unsigned char *key);
    void (*generate) (unsigned char *blk, int len, unsigned long seq);
    int (*verify) (unsigned char *blk, int len, unsigned long seq);
    char *name;
    int len;
};

struct ssh_kex {
    /*
     * Plugging in another KEX algorithm requires structural chaos,
     * so it's hard to abstract them into nice little structures
     * like this. Hence, for the moment, this is just a
     * placeholder. I claim justification in the fact that OpenSSH
     * does this too :-)
     */
    char *name;
};

struct ssh_signkey {
    void *(*newkey) (char *data, int len);
    void (*freekey) (void *key);
    char *(*fmtkey) (void *key);
    unsigned char *(*public_blob) (void *key, int *len);
    unsigned char *(*private_blob) (void *key, int *len);
    void *(*createkey) (unsigned char *pub_blob, int pub_len,
			unsigned char *priv_blob, int priv_len);
    void *(*openssh_createkey) (unsigned char **blob, int *len);
    int (*openssh_fmtkey) (void *key, unsigned char *blob, int len);
    char *(*fingerprint) (void *key);
    int (*verifysig) (void *key, char *sig, int siglen,
		      char *data, int datalen);
    unsigned char *(*sign) (void *key, char *data, int datalen,
			    int *siglen);
    char *name;
    char *keytype;		       /* for host key cache */
};

struct ssh_compress {
    char *name;
    void (*compress_init) (void);
    int (*compress) (unsigned char *block, int len,
		     unsigned char **outblock, int *outlen);
    void (*decompress_init) (void);
    int (*decompress) (unsigned char *block, int len,
		       unsigned char **outblock, int *outlen);
    int (*disable_compression) (void);
};

struct ssh2_userkey {
    const struct ssh_signkey *alg;     /* the key algorithm */
    void *data;			       /* the key data */
    char *comment;		       /* the key comment */
};

extern const struct ssh_cipher ssh_3des;
extern const struct ssh_cipher ssh_des;
extern const struct ssh_cipher ssh_blowfish_ssh1;
extern const struct ssh2_ciphers ssh2_3des;
extern const struct ssh2_ciphers ssh2_aes;
extern const struct ssh2_ciphers ssh2_blowfish;
extern const struct ssh_kex ssh_diffiehellman;
extern const struct ssh_kex ssh_diffiehellman_gex;
extern const struct ssh_signkey ssh_dss;
extern const struct ssh_signkey ssh_rsa;
extern const struct ssh_mac ssh_md5;
extern const struct ssh_mac ssh_sha1;
extern const struct ssh_mac ssh_sha1_buggy;

/*
 * PuTTY version number formatted as an SSH version string. 
 */
extern char sshver[];

#ifndef MSCRYPTOAPI
void SHATransform(word32 * digest, word32 * data);
#endif

int random_byte(void);
void random_add_noise(void *noise, int length);
void random_add_heavynoise(void *noise, int length);

void logevent(char *);

Bignum copybn(Bignum b);
Bignum bn_power_2(int n);
void bn_restore_invariant(Bignum b);
Bignum bignum_from_short(unsigned short n);
void freebn(Bignum b);
Bignum modpow(Bignum base, Bignum exp, Bignum mod);
Bignum modmul(Bignum a, Bignum b, Bignum mod);
void decbn(Bignum n);
extern Bignum Zero, One;
Bignum bignum_from_bytes(unsigned char *data, int nbytes);
int ssh1_read_bignum(unsigned char *data, Bignum * result);
int bignum_bitcount(Bignum bn);
int ssh1_bignum_length(Bignum bn);
int ssh2_bignum_length(Bignum bn);
int bignum_byte(Bignum bn, int i);
int bignum_bit(Bignum bn, int i);
void bignum_set_bit(Bignum bn, int i, int value);
int ssh1_write_bignum(void *data, Bignum bn);
Bignum biggcd(Bignum a, Bignum b);
unsigned short bignum_mod_short(Bignum number, unsigned short modulus);
Bignum bignum_add_long(Bignum number, unsigned long addend);
Bignum bigmul(Bignum a, Bignum b);
Bignum modinv(Bignum number, Bignum modulus);
Bignum bignum_bitmask(Bignum number);
Bignum bignum_rshift(Bignum number, int shift);
int bignum_cmp(Bignum a, Bignum b);
char *bignum_decimal(Bignum x);

void dh_setup_group1(void);
void dh_setup_group(Bignum pval, Bignum gval);
void dh_cleanup(void);
Bignum dh_create_e(int nbits);
Bignum dh_find_K(Bignum f);

int loadrsakey(char *filename, struct RSAKey *key, char *passphrase);
int rsakey_encrypted(char *filename, char **comment);

int saversakey(char *filename, struct RSAKey *key, char *passphrase);

void base64_encode_atom(unsigned char *data, int n, char *out);

/* ssh2_load_userkey can return this as an error */
extern struct ssh2_userkey ssh2_wrong_passphrase;
#define SSH2_WRONG_PASSPHRASE (&ssh2_wrong_passphrase)

int ssh2_userkey_encrypted(char *filename, char **comment);
struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase);
char *ssh2_userkey_loadpub(char *filename, char **algorithm,
			   int *pub_blob_len);
int ssh2_save_userkey(char *filename, struct ssh2_userkey *key,
		      char *passphrase);

int keyfile_version(char *filename);

void des3_decrypt_pubkey(unsigned char *key, unsigned char *blk, int len);
void des3_encrypt_pubkey(unsigned char *key, unsigned char *blk, int len);
void aes256_encrypt_pubkey(unsigned char *key, unsigned char *blk,
			   int len);
void aes256_decrypt_pubkey(unsigned char *key, unsigned char *blk,
			   int len);

/*
 * For progress updates in the key generation utility.
 */
typedef void (*progfn_t) (void *param, int phase, int progress);

int rsa_generate(struct RSAKey *key, int bits, progfn_t pfn,
		 void *pfnparam);
Bignum primegen(int bits, int modulus, int residue, int phase,
		progfn_t pfn, void *pfnparam);

/*
 * zlib compression.
 */
void zlib_compress_init(void);
void zlib_decompress_init(void);
int zlib_compress_block(unsigned char *block, int len,
			unsigned char **outblock, int *outlen);
int zlib_decompress_block(unsigned char *block, int len,
			  unsigned char **outblock, int *outlen);

/*
 * SSH1 agent messages.
 */
#define SSH1_AGENTC_REQUEST_RSA_IDENTITIES    1
#define SSH1_AGENT_RSA_IDENTITIES_ANSWER      2
#define SSH1_AGENTC_RSA_CHALLENGE             3
#define SSH1_AGENT_RSA_RESPONSE               4
#define SSH1_AGENTC_ADD_RSA_IDENTITY          7
#define SSH1_AGENTC_REMOVE_RSA_IDENTITY       8
#define SSH1_AGENTC_REMOVE_ALL_RSA_IDENTITIES 9	/* openssh private? */

/*
 * Messages common to SSH1 and OpenSSH's SSH2.
 */
#define SSH_AGENT_FAILURE                    5
#define SSH_AGENT_SUCCESS                    6

/*
 * OpenSSH's SSH2 agent messages.
 */
#define SSH2_AGENTC_REQUEST_IDENTITIES          11
#define SSH2_AGENT_IDENTITIES_ANSWER            12
#define SSH2_AGENTC_SIGN_REQUEST                13
#define SSH2_AGENT_SIGN_RESPONSE                14
#define SSH2_AGENTC_ADD_IDENTITY                17
#define SSH2_AGENTC_REMOVE_IDENTITY             18
#define SSH2_AGENTC_REMOVE_ALL_IDENTITIES       19
Commit	Line	Data
37508af4	1	#include <string.h>
37508af4	2
dcbde236	3	#include "puttymem.h"
dcbde236	4
e5574168	5	/*
	6	* Useful thing.
	7	*/
	8	#ifndef lenof
	9	#define lenof(x) ( (sizeof((x))) / (sizeof(*(x))))
	10	#endif
	11
bea1ef5f	12	#define SSH_CIPHER_IDEA 1
9697bfd2	13	#define SSH_CIPHER_DES 2
bea1ef5f	14	#define SSH_CIPHER_3DES 3
	15	#define SSH_CIPHER_BLOWFISH 6
	16
e5574168	17	#ifdef MSCRYPTOAPI
	18	#define APIEXTRA 8
	19	#else
	20	#define APIEXTRA 0
	21	#endif
	22
3709bfe9	23	#ifndef BIGNUM_INTERNAL
	24	typedef void *Bignum;
	25	#endif
7cca0d81	26
374330e2	27	struct RSAKey {
	28	int bits;
	29	int bytes;
8f203108	30	#ifdef MSCRYPTOAPI
	31	unsigned long exponent;
	32	unsigned char *modulus;
	33	#else
7cca0d81	34	Bignum modulus;
	35	Bignum exponent;
	36	Bignum private_exponent;
9400cf6f	37	Bignum p;
	38	Bignum q;
	39	Bignum iqmp;
65a22376	40	#endif
65a22376	41	char *comment;
9400cf6f	42	};
9400cf6f	43
374330e2	44	int makekey(unsigned char data, struct RSAKey result,
7cca0d81	45	unsigned char **keystr, int order);
7cca0d81	46	int makeprivate(unsigned char data, struct RSAKey result);
374330e2	47	void rsaencrypt(unsigned char data, int length, struct RSAKey key);
7cca0d81	48	Bignum rsadecrypt(Bignum input, struct RSAKey *key);
	49	void rsasign(unsigned char data, int length, struct RSAKey key);
	50	void rsasanitise(struct RSAKey *key);
374330e2	51	int rsastr_len(struct RSAKey *key);
374330e2	52	void rsastr_fmt(char str, struct RSAKey key);
1c2a93c4	53	void rsa_fingerprint(char str, int len, struct RSAKey key);
014970c8	54	int rsa_verify(struct RSAKey *key);
5c58ad2d	55	void freersakey(struct RSAKey *key);
374330e2	56
	57	typedef unsigned int word32;
	58	typedef unsigned int uint32;
	59
8160fbfc	60	unsigned long crc32(const void *s, size_t len);
374330e2	61
48672163	62	typedef struct {
	63	uint32 h[4];
	64	} MD5_Core_State;
	65
374330e2	66	struct MD5Context {
8f203108	67	#ifdef MSCRYPTOAPI
	68	unsigned long hHash;
	69	#else
48672163	70	MD5_Core_State core;
bb093ca7	71	unsigned char block[64];
48672163	72	int blkused;
48672163	73	uint32 lenhi, lenlo;
8f203108	74	#endif
374330e2	75	};
	76
	77	void MD5Init(struct MD5Context *context);
	78	void MD5Update(struct MD5Context context, unsigned char const buf,
32874aea	79	unsigned len);
374330e2	80	void MD5Final(unsigned char digest[16], struct MD5Context *context);
374330e2	81
e5574168	82	typedef struct {
	83	uint32 h[5];
	84	unsigned char block[64];
	85	int blkused;
	86	uint32 lenhi, lenlo;
	87	} SHA_State;
	88
32874aea	89	void SHA_Init(SHA_State * s);
	90	void SHA_Bytes(SHA_State * s, void *p, int len);
	91	void SHA_Final(SHA_State * s, unsigned char *output);
7cca0d81	92	void SHA_Simple(void p, int len, unsigned char output);
e5574168	93
374330e2	94	struct ssh_cipher {
32874aea	95	void (sesskey) (unsigned char key); /* for ssh 1 */
	96	void (encrypt) (unsigned char blk, int len);
	97	void (decrypt) (unsigned char blk, int len);
0a3f1d48	98	int blksize;
	99	};
	100
	101	struct ssh2_cipher {
32874aea	102	void (setcsiv) (unsigned char key); /* for ssh 2 */
	103	void (setcskey) (unsigned char key); /* for ssh 2 */
	104	void (setsciv) (unsigned char key); /* for ssh 2 */
	105	void (setsckey) (unsigned char key); /* for ssh 2 */
	106	void (encrypt) (unsigned char blk, int len);
	107	void (decrypt) (unsigned char blk, int len);
e5574168	108	char *name;
e5574168	109	int blksize;
d2a0e0be	110	int keylen;
e5574168	111	};
e5574168	112
0a3f1d48	113	struct ssh2_ciphers {
0a3f1d48	114	int nciphers;
65a22376	115	const struct ssh2_cipher const list;
0a3f1d48	116	};
0a3f1d48	117
e5574168	118	struct ssh_mac {
32874aea	119	void (setcskey) (unsigned char key);
	120	void (setsckey) (unsigned char key);
	121	void (generate) (unsigned char blk, int len, unsigned long seq);
	122	int (verify) (unsigned char blk, int len, unsigned long seq);
e5574168	123	char *name;
	124	int len;
	125	};
	126
	127	struct ssh_kex {
7cca0d81	128	/*
	129	* Plugging in another KEX algorithm requires structural chaos,
	130	* so it's hard to abstract them into nice little structures
	131	* like this. Hence, for the moment, this is just a
	132	* placeholder. I claim justification in the fact that OpenSSH
	133	* does this too :-)
	134	*/
e5574168	135	char *name;
	136	};
	137
e055a386	138	struct ssh_signkey {
32874aea	139	void (newkey) (char *data, int len);
	140	void (freekey) (void key);
	141	char (fmtkey) (void *key);
	142	unsigned char (public_blob) (void key, int len);
	143	unsigned char (private_blob) (void key, int len);
	144	void (createkey) (unsigned char *pub_blob, int pub_len,
	145	unsigned char *priv_blob, int priv_len);
	146	void (openssh_createkey) (unsigned char *blob, int len);
	147	int (openssh_fmtkey) (void key, unsigned char *blob, int len);
	148	char (fingerprint) (void *key);
	149	int (verifysig) (void key, char *sig, int siglen,
	150	char *data, int datalen);
	151	unsigned char (sign) (void key, char data, int datalen,
	152	int *siglen);
e5574168	153	char *name;
32874aea	154	char keytype; / for host key cache */
e5574168	155	};
	156
	157	struct ssh_compress {
	158	char *name;
32874aea	159	void (*compress_init) (void);
	160	int (compress) (unsigned char block, int len,
	161	unsigned char *outblock, int outlen);
	162	void (*decompress_init) (void);
	163	int (decompress) (unsigned char block, int len,
	164	unsigned char *outblock, int outlen);
	165	int (*disable_compression) (void);
374330e2	166	};
374330e2	167
65a22376	168	struct ssh2_userkey {
	169	const struct ssh_signkey alg; / the key algorithm */
	170	void data; / the key data */
	171	char comment; / the key comment */
	172	};
	173
	174	extern const struct ssh_cipher ssh_3des;
	175	extern const struct ssh_cipher ssh_des;
	176	extern const struct ssh_cipher ssh_blowfish_ssh1;
	177	extern const struct ssh2_ciphers ssh2_3des;
	178	extern const struct ssh2_ciphers ssh2_aes;
	179	extern const struct ssh2_ciphers ssh2_blowfish;
	180	extern const struct ssh_kex ssh_diffiehellman;
	181	extern const struct ssh_kex ssh_diffiehellman_gex;
	182	extern const struct ssh_signkey ssh_dss;
	183	extern const struct ssh_signkey ssh_rsa;
	184	extern const struct ssh_mac ssh_md5;
	185	extern const struct ssh_mac ssh_sha1;
	186	extern const struct ssh_mac ssh_sha1_buggy;
	187
900a4ee6	188	/*
	189	* PuTTY version number formatted as an SSH version string.
	190	*/
	191	extern char sshver[];
	192
8f203108	193	#ifndef MSCRYPTOAPI
32874aea	194	void SHATransform(word32 * digest, word32 * data);
8f203108	195	#endif
374330e2	196
	197	int random_byte(void);
	198	void random_add_noise(void *noise, int length);
6e522441	199	void random_add_heavynoise(void *noise, int length);
c5e9c988	200
32874aea	201	void logevent(char *);
e5574168	202
7cca0d81	203	Bignum copybn(Bignum b);
3709bfe9	204	Bignum bn_power_2(int n);
3709bfe9	205	void bn_restore_invariant(Bignum b);
9400cf6f	206	Bignum bignum_from_short(unsigned short n);
e5574168	207	void freebn(Bignum b);
59600f67	208	Bignum modpow(Bignum base, Bignum exp, Bignum mod);
59600f67	209	Bignum modmul(Bignum a, Bignum b, Bignum mod);
7cca0d81	210	void decbn(Bignum n);
7cca0d81	211	extern Bignum Zero, One;
3709bfe9	212	Bignum bignum_from_bytes(unsigned char *data, int nbytes);
32874aea	213	int ssh1_read_bignum(unsigned char data, Bignum result);
ddecd643	214	int bignum_bitcount(Bignum bn);
5c58ad2d	215	int ssh1_bignum_length(Bignum bn);
260f3dec	216	int ssh2_bignum_length(Bignum bn);
5c58ad2d	217	int bignum_byte(Bignum bn, int i);
9400cf6f	218	int bignum_bit(Bignum bn, int i);
9400cf6f	219	void bignum_set_bit(Bignum bn, int i, int value);
5c58ad2d	220	int ssh1_write_bignum(void *data, Bignum bn);
9400cf6f	221	Bignum biggcd(Bignum a, Bignum b);
	222	unsigned short bignum_mod_short(Bignum number, unsigned short modulus);
	223	Bignum bignum_add_long(Bignum number, unsigned long addend);
	224	Bignum bigmul(Bignum a, Bignum b);
	225	Bignum modinv(Bignum number, Bignum modulus);
3709bfe9	226	Bignum bignum_bitmask(Bignum number);
9400cf6f	227	Bignum bignum_rshift(Bignum number, int shift);
8c3cd914	228	int bignum_cmp(Bignum a, Bignum b);
6e522441	229	char *bignum_decimal(Bignum x);
e5574168	230
3709bfe9	231	void dh_setup_group1(void);
a92dd380	232	void dh_setup_group(Bignum pval, Bignum gval);
3709bfe9	233	void dh_cleanup(void);
7bd5a860	234	Bignum dh_create_e(int nbits);
e5574168	235	Bignum dh_find_K(Bignum f);
7cca0d81	236
65a22376	237	int loadrsakey(char filename, struct RSAKey key, char *passphrase);
a52f067e	238	int rsakey_encrypted(char filename, char *comment);
7cca0d81	239
65a22376	240	int saversakey(char filename, struct RSAKey key, char *passphrase);
	241
	242	void base64_encode_atom(unsigned char data, int n, char out);
	243
	244	/* ssh2_load_userkey can return this as an error */
	245	extern struct ssh2_userkey ssh2_wrong_passphrase;
	246	#define SSH2_WRONG_PASSPHRASE (&ssh2_wrong_passphrase)
	247
	248	int ssh2_userkey_encrypted(char filename, char *comment);
	249	struct ssh2_userkey ssh2_load_userkey(char filename, char *passphrase);
32874aea	250	char ssh2_userkey_loadpub(char filename, char **algorithm,
	251	int *pub_blob_len);
	252	int ssh2_save_userkey(char filename, struct ssh2_userkey key,
	253	char *passphrase);
65a22376	254
65a22376	255	int keyfile_version(char *filename);
6e522441	256
65a22376	257	void des3_decrypt_pubkey(unsigned char key, unsigned char blk, int len);
65a22376	258	void des3_encrypt_pubkey(unsigned char key, unsigned char blk, int len);
32874aea	259	void aes256_encrypt_pubkey(unsigned char key, unsigned char blk,
	260	int len);
	261	void aes256_decrypt_pubkey(unsigned char key, unsigned char blk,
	262	int len);
9400cf6f	263
	264	/*
	265	* For progress updates in the key generation utility.
	266	*/
32874aea	267	typedef void (progfn_t) (void param, int phase, int progress);
9400cf6f	268
32874aea	269	int rsa_generate(struct RSAKey *key, int bits, progfn_t pfn,
	270	void *pfnparam);
	271	Bignum primegen(int bits, int modulus, int residue, int phase,
	272	progfn_t pfn, void *pfnparam);
4ba9b64b	273
	274	/*
	275	* zlib compression.
	276	*/
	277	void zlib_compress_init(void);
	278	void zlib_decompress_init(void);
	279	int zlib_compress_block(unsigned char *block, int len,
	280	unsigned char *outblock, int outlen);
	281	int zlib_decompress_block(unsigned char *block, int len,
	282	unsigned char *outblock, int outlen);
1983e559	283
	284	/*
	285	* SSH1 agent messages.
	286	*/
	287	#define SSH1_AGENTC_REQUEST_RSA_IDENTITIES 1
	288	#define SSH1_AGENT_RSA_IDENTITIES_ANSWER 2
	289	#define SSH1_AGENTC_RSA_CHALLENGE 3
	290	#define SSH1_AGENT_RSA_RESPONSE 4
	291	#define SSH1_AGENTC_ADD_RSA_IDENTITY 7
	292	#define SSH1_AGENTC_REMOVE_RSA_IDENTITY 8
32874aea	293	#define SSH1_AGENTC_REMOVE_ALL_RSA_IDENTITIES 9 /* openssh private? */
1983e559	294
	295	/*
	296	* Messages common to SSH1 and OpenSSH's SSH2.
	297	*/
	298	#define SSH_AGENT_FAILURE 5
	299	#define SSH_AGENT_SUCCESS 6
	300
	301	/*
	302	* OpenSSH's SSH2 agent messages.
	303	*/
	304	#define SSH2_AGENTC_REQUEST_IDENTITIES 11
	305	#define SSH2_AGENT_IDENTITIES_ANSWER 12
	306	#define SSH2_AGENTC_SIGN_REQUEST 13
	307	#define SSH2_AGENT_SIGN_RESPONSE 14
	308	#define SSH2_AGENTC_ADD_IDENTITY 17
	309	#define SSH2_AGENTC_REMOVE_IDENTITY 18
	310	#define SSH2_AGENTC_REMOVE_ALL_IDENTITIES 19