[u/mdw/putty] / portfwd.c

#include <stdio.h>
#include <stdlib.h>

#include "putty.h"
#include "ssh.h"

#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif

#define GET_32BIT_LSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0]) | \
  ((unsigned long)(unsigned char)(cp)[1] << 8) | \
  ((unsigned long)(unsigned char)(cp)[2] << 16) | \
  ((unsigned long)(unsigned char)(cp)[3] << 24))

#define PUT_32BIT_LSB_FIRST(cp, value) ( \
  (cp)[0] = (value), \
  (cp)[1] = (value) >> 8, \
  (cp)[2] = (value) >> 16, \
  (cp)[3] = (value) >> 24 )

#define GET_16BIT_LSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0]) | \
  ((unsigned long)(unsigned char)(cp)[1] << 8))

#define PUT_16BIT_LSB_FIRST(cp, value) ( \
  (cp)[0] = (value), \
  (cp)[1] = (value) >> 8 )

#define GET_32BIT_MSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0] << 24) | \
  ((unsigned long)(unsigned char)(cp)[1] << 16) | \
  ((unsigned long)(unsigned char)(cp)[2] << 8) | \
  ((unsigned long)(unsigned char)(cp)[3]))

#define PUT_32BIT_MSB_FIRST(cp, value) ( \
  (cp)[0] = (value) >> 24, \
  (cp)[1] = (value) >> 16, \
  (cp)[2] = (value) >> 8, \
  (cp)[3] = (value) )

#define GET_16BIT_MSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0] << 8) | \
  ((unsigned long)(unsigned char)(cp)[1]))

#define PUT_16BIT_MSB_FIRST(cp, value) ( \
  (cp)[0] = (value) >> 8, \
  (cp)[1] = (value) )

struct PFwdPrivate {
    const struct plug_function_table *fn;
    /* the above variable absolutely *must* be the first in this structure */
    void *c;			       /* (channel) data used by ssh.c */
    void *backhandle;		       /* instance of SSH backend itself */
    /* Note that backhandle need not be filled in if c is non-NULL */
    Socket s;
    int throttled, throttle_override;
    int ready;
    /*
     * `dynamic' does double duty. It's set to 0 for an ordinary
     * forwarded port, and nonzero for SOCKS-style dynamic port
     * forwarding; but it also represents the state of the SOCKS
     * exchange.
     */
    int dynamic;
    /*
     * `hostname' and `port' are the real hostname and port, once
     * we know what we're connecting to; they're unused for this
     * purpose while conducting a local SOCKS exchange, which means
     * we can also use them as a buffer and pointer for reading
     * data from the SOCKS client.
     */
    char hostname[256+8];
    int port;
    /*
     * When doing dynamic port forwarding, we can receive
     * connection data before we are actually able to send it; so
     * we may have to temporarily hold some in a dynamically
     * allocated buffer here.
     */
    void *buffer;
    int buflen;
};

static int pfd_closing(Plug plug, char *error_msg, int error_code,
		       int calling_back)
{
    struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;

    /*
     * We have no way to communicate down the forwarded connection,
     * so if an error occurred on the socket, we just ignore it
     * and treat it like a proper close.
     */
    if (pr->c)
	sshfwd_close(pr->c);
    pfd_close(pr->s);
    return 1;
}

static int pfd_receive(Plug plug, int urgent, char *data, int len)
{
    struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
    if (pr->dynamic) {
	while (len--) {
	    if (pr->port >= lenof(pr->hostname)) {
		if ((pr->dynamic >> 12) == 4) {
		    /* Send back a SOCKS 4 error before closing. */
		    char data[8];
		    memset(data, 0, sizeof(data));
		    data[1] = 91;      /* generic `request rejected' */
		    sk_write(pr->s, data, 8);
		}
		pfd_close(pr->s);
		return 1;
	    }
	    pr->hostname[pr->port++] = *data++;

	    /*
	     * Now check what's in the buffer to see if it's a
	     * valid and complete message in the SOCKS exchange.
	     */
	    if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) &&
		pr->hostname[0] == 4) {
		/*
		 * SOCKS 4.
		 */
		if (pr->dynamic == 1)
		    pr->dynamic = 0x4000;
		if (pr->port < 2) continue;/* don't have command code yet */
		if (pr->hostname[1] != 1) {
		    /* Send back a SOCKS 4 error before closing. */
		    char data[8];
		    memset(data, 0, sizeof(data));
		    data[1] = 91;      /* generic `request rejected' */
		    sk_write(pr->s, data, 8);
		    pfd_close(pr->s);
		    return 1;
		}
		if (pr->port < 8) continue;   /* haven't started username */
		if (pr->hostname[pr->port-1] != 0)
		    continue;	       /* haven't _finished_ username */
		/*
		 * Now we have a full SOCKS 4 request. Check it to
		 * see if it's a SOCKS 4A request.
		 */
		if (pr->hostname[4] == 0 && pr->hostname[5] == 0 &&
		    pr->hostname[6] == 0 && pr->hostname[7] != 0) {
		    /*
		     * It's SOCKS 4A. So if we haven't yet
		     * collected the host name, we should continue
		     * waiting for data in order to do so; if we
		     * have, we can go ahead.
		     */
		    int len;
		    if (pr->dynamic == 0x4000) {
			pr->dynamic = 0x4001;
			pr->port = 8;      /* reset buffer to overwrite name */
			continue;
		    }
		    pr->hostname[0] = 0;   /* reply version code */
		    pr->hostname[1] = 90;   /* request granted */
		    sk_write(pr->s, pr->hostname, 8);
		    len= pr->port;
		    pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
		    memmove(pr->hostname, pr->hostname + 8, len);
		    goto connect;
		} else {
		    /*
		     * It's SOCKS 4, which means we should format
		     * the IP address into the hostname string and
		     * then just go.
		     */
		    pr->hostname[0] = 0;   /* reply version code */
		    pr->hostname[1] = 90;   /* request granted */
		    sk_write(pr->s, pr->hostname, 8);
		    pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
		    sprintf(pr->hostname, "%d.%d.%d.%d",
			    (unsigned char)pr->hostname[4],
			    (unsigned char)pr->hostname[5],
			    (unsigned char)pr->hostname[6],
			    (unsigned char)pr->hostname[7]);
		    goto connect;
		}
	    }

	    if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) &&
		pr->hostname[0] == 5) {
		/*
		 * SOCKS 5.
		 */
		if (pr->dynamic == 1)
		    pr->dynamic = 0x5000;

		if (pr->dynamic == 0x5000) {
		    int i, method;
		    char data[2];
		    /*
		     * We're receiving a set of method identifiers.
		     */
		    if (pr->port < 2) continue;/* no method count yet */
		    if (pr->port < 2 + (unsigned char)pr->hostname[1])
			continue;      /* no methods yet */
		    method = 0xFF;     /* invalid */
		    for (i = 0; i < (unsigned char)pr->hostname[1]; i++)
			if (pr->hostname[2+i] == 0) {
			    method = 0;/* no auth */
			    break;
			}
		    data[0] = 5;
		    data[1] = method;
		    sk_write(pr->s, data, 2);
		    pr->dynamic = 0x5001;
		    pr->port = 0;      /* re-empty the buffer */
		    continue;
		}

		if (pr->dynamic == 0x5001) {
		    int atype, alen;
		    if (pr->port < 6) continue;
		    atype = (unsigned char)pr->hostname[3];
		    if (atype == 1)    /* IPv4 address */
			alen = 4;
		    if (atype == 4)    /* IPv6 address */
			alen = 16;
		    if (atype == 3)    /* domain name has leading length */
			alen = 1 + (unsigned char)pr->hostname[4];
		    if (pr->port < 6 + alen) continue;
		    if (pr->hostname[1] != 1 || pr->hostname[2] != 0) {
			pr->hostname[1] = 1;   /* generic failure */
			pr->hostname[2] = 0;   /* reserved */
			sk_write(pr->s, pr->hostname, pr->port);
			pfd_close(pr->s);
			return 1;
		    }
		    /*
		     * Now we have a viable connect request. Switch
		     * on atype.
		     */
		    pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen);
		    if (atype == 1) {
			pr->hostname[1] = 0;   /* succeeded */
			sk_write(pr->s, pr->hostname, alen + 6);
			sprintf(pr->hostname, "%d.%d.%d.%d",
				(unsigned char)pr->hostname[4],
				(unsigned char)pr->hostname[5],
				(unsigned char)pr->hostname[6],
				(unsigned char)pr->hostname[7]);
			goto connect;
		    } else if (atype == 3) {
			pr->hostname[1] = 0;   /* succeeded */
			sk_write(pr->s, pr->hostname, alen + 6);
			memmove(pr->hostname, pr->hostname + 5, alen-1);
			pr->hostname[alen-1] = '\0';
			goto connect;
		    } else {
			/*
			 * Unknown address type. (FIXME: support IPv6!)
			 */
			pr->hostname[1] = 8;   /* atype not supported */
			sk_write(pr->s, pr->hostname, pr->port);
			pfd_close(pr->s);
			return 1;			
		    }
		}
	    }
	    
	    /*
	     * If we get here without either having done `continue'
	     * or `goto connect', it must be because there is no
	     * sensible interpretation of what's in our buffer. So
	     * close the connection rudely.
	     */
	    pfd_close(pr->s);
	    return 1;
	}
	return 1;

	/*
	 * We come here when we're ready to make an actual
	 * connection.
	 */
	connect:

	pr->c = new_sock_channel(pr->backhandle, pr->s);
	if (pr->c == NULL) {
	    pfd_close(pr->s);
	    return 1;
	} else {
	    /* asks to forward to the specified host/port for this */
	    ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
	}
	pr->dynamic = 0;

	/*
	 * Now freeze the socket until the SSH server confirms the
	 * connection.
	 */
	sk_set_frozen(pr->s, 1);
	/*
	 * If there's any data remaining in our current buffer,
	 * save it to be sent on pfd_confirm().
	 */
	if (len > 0) {
	    pr->buffer = snewn(len, char);
	    memcpy(pr->buffer, data, len);
	    pr->buflen = len;
	}
    }
    if (pr->ready) {
	if (sshfwd_write(pr->c, data, len) > 0) {
	    pr->throttled = 1;
	    sk_set_frozen(pr->s, 1);
	}
    }
    return 1;
}

static void pfd_sent(Plug plug, int bufsize)
{
    struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;

    if (pr->c)
	sshfwd_unthrottle(pr->c, bufsize);
}

/*
 * Called when receiving a PORT OPEN from the server
 */
char *pfd_newconnect(Socket *s, char *hostname, int port, void *c,
		     const Config *cfg)
{
    static const struct plug_function_table fn_table = {
	pfd_closing,
	pfd_receive,
	pfd_sent,
	NULL
    };

    SockAddr addr;
    char *err, *dummy_realhost;
    struct PFwdPrivate *pr;

    /*
     * Try to find host.
     */
    addr = name_lookup(hostname, port, &dummy_realhost, cfg);
    if ((err = sk_addr_error(addr)) != NULL)
	return err;

    /*
     * Open socket.
     */
    pr = snew(struct PFwdPrivate);
    pr->buffer = NULL;
    pr->fn = &fn_table;
    pr->throttled = pr->throttle_override = 0;
    pr->ready = 1;
    pr->c = c;
    pr->backhandle = NULL;	       /* we shouldn't need this */

    pr->s = *s = new_connection(addr, dummy_realhost, port,
				0, 1, 0, (Plug) pr, cfg);
    if ((err = sk_socket_error(*s)) != NULL) {
	sfree(pr);
	return err;
    }

    sk_set_private_ptr(*s, pr);
    sk_addr_free(addr);
    return NULL;
}

/*
 called when someone connects to the local port
 */

static int pfd_accepting(Plug p, void *sock)
{
    static const struct plug_function_table fn_table = {
	pfd_closing,
	pfd_receive,
	pfd_sent,
	NULL
    };
    struct PFwdPrivate *pr, *org;
    Socket s;
    char *err;

    org = (struct PFwdPrivate *)p;
    pr = snew(struct PFwdPrivate);
    pr->buffer = NULL;
    pr->fn = &fn_table;

    pr->c = NULL;
    pr->backhandle = org->backhandle;

    pr->s = s = sk_register(sock, (Plug) pr);
    if ((err = sk_socket_error(s)) != NULL) {
	sfree(pr);
	return err != NULL;
    }

    sk_set_private_ptr(s, pr);

    pr->throttled = pr->throttle_override = 0;
    pr->ready = 0;

    if (org->dynamic) {
	pr->dynamic = 1;
	pr->port = 0;		       /* hostname buffer is so far empty */
	sk_set_frozen(s, 0);	       /* we want to receive SOCKS _now_! */
    } else {
	strcpy(pr->hostname, org->hostname);
	pr->port = org->port;	
	pr->c = new_sock_channel(org->backhandle, s);

	if (pr->c == NULL) {
	    sfree(pr);
	    return 1;
	} else {
	    /* asks to forward to the specified host/port for this */
	    ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
	}
    }

    return 0;
}


/* Add a new forwarding from port -> desthost:destport
 sets up a listener on the local machine on (srcaddr:)port
 */
char *pfd_addforward(char *desthost, int destport, char *srcaddr, int port,
		     void *backhandle, const Config *cfg)
{
    static const struct plug_function_table fn_table = {
	pfd_closing,
	pfd_receive,		       /* should not happen... */
	pfd_sent,		       /* also should not happen */
	pfd_accepting
    };

    char *err;
    struct PFwdPrivate *pr;
    Socket s;

    /*
     * Open socket.
     */
    pr = snew(struct PFwdPrivate);
    pr->buffer = NULL;
    pr->fn = &fn_table;
    pr->c = NULL;
    if (desthost) {
	strcpy(pr->hostname, desthost);
	pr->port = destport;
	pr->dynamic = 0;
    } else
	pr->dynamic = 1;
    pr->throttled = pr->throttle_override = 0;
    pr->ready = 0;
    pr->backhandle = backhandle;

    pr->s = s = new_listener(srcaddr, port, (Plug) pr,
			     !cfg->lport_acceptall, cfg);
    if ((err = sk_socket_error(s)) != NULL) {
	sfree(pr);
	return err;
    }

    sk_set_private_ptr(s, pr);

    return NULL;
}

void pfd_close(Socket s)
{
    struct PFwdPrivate *pr;

    if (!s)
	return;

    pr = (struct PFwdPrivate *) sk_get_private_ptr(s);

    sfree(pr->buffer);
    sfree(pr);

    sk_close(s);
}

void pfd_unthrottle(Socket s)
{
    struct PFwdPrivate *pr;
    if (!s)
	return;
    pr = (struct PFwdPrivate *) sk_get_private_ptr(s);

    pr->throttled = 0;
    sk_set_frozen(s, pr->throttled || pr->throttle_override);
}

void pfd_override_throttle(Socket s, int enable)
{
    struct PFwdPrivate *pr;
    if (!s)
	return;
    pr = (struct PFwdPrivate *) sk_get_private_ptr(s);

    pr->throttle_override = enable;
    sk_set_frozen(s, pr->throttled || pr->throttle_override);
}

/*
 * Called to send data down the raw connection.
 */
int pfd_send(Socket s, char *data, int len)
{
    if (s == NULL)
	return 0;
    return sk_write(s, data, len);
}


void pfd_confirm(Socket s)
{
    struct PFwdPrivate *pr;

    if (s == NULL)
	return;

    pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
    pr->ready = 1;
    sk_set_frozen(s, 0);
    sk_write(s, NULL, 0);
    if (pr->buffer) {
	sshfwd_write(pr->c, pr->buffer, pr->buflen);
	sfree(pr->buffer);
	pr->buffer = NULL;
    }
}
Commit	Line	Data
f26d5c33	1	#include <stdio.h>
	2	#include <stdlib.h>
	3
	4	#include "putty.h"
	5	#include "ssh.h"
	6
	7	#ifndef FALSE
	8	#define FALSE 0
	9	#endif
	10	#ifndef TRUE
	11	#define TRUE 1
	12	#endif
	13
	14	#define GET_32BIT_LSB_FIRST(cp) \
	15	(((unsigned long)(unsigned char)(cp)[0]) \| \
	16	((unsigned long)(unsigned char)(cp)[1] << 8) \| \
	17	((unsigned long)(unsigned char)(cp)[2] << 16) \| \
	18	((unsigned long)(unsigned char)(cp)[3] << 24))
	19
	20	#define PUT_32BIT_LSB_FIRST(cp, value) ( \
	21	(cp)[0] = (value), \
	22	(cp)[1] = (value) >> 8, \
	23	(cp)[2] = (value) >> 16, \
	24	(cp)[3] = (value) >> 24 )
	25
	26	#define GET_16BIT_LSB_FIRST(cp) \
	27	(((unsigned long)(unsigned char)(cp)[0]) \| \
	28	((unsigned long)(unsigned char)(cp)[1] << 8))
	29
	30	#define PUT_16BIT_LSB_FIRST(cp, value) ( \
	31	(cp)[0] = (value), \
	32	(cp)[1] = (value) >> 8 )
	33
	34	#define GET_32BIT_MSB_FIRST(cp) \
	35	(((unsigned long)(unsigned char)(cp)[0] << 24) \| \
	36	((unsigned long)(unsigned char)(cp)[1] << 16) \| \
	37	((unsigned long)(unsigned char)(cp)[2] << 8) \| \
	38	((unsigned long)(unsigned char)(cp)[3]))
	39
	40	#define PUT_32BIT_MSB_FIRST(cp, value) ( \
	41	(cp)[0] = (value) >> 24, \
	42	(cp)[1] = (value) >> 16, \
	43	(cp)[2] = (value) >> 8, \
	44	(cp)[3] = (value) )
	45
	46	#define GET_16BIT_MSB_FIRST(cp) \
	47	(((unsigned long)(unsigned char)(cp)[0] << 8) \| \
	48	((unsigned long)(unsigned char)(cp)[1]))
	49
	50	#define PUT_16BIT_MSB_FIRST(cp, value) ( \
	51	(cp)[0] = (value) >> 8, \
	52	(cp)[1] = (value) )
	53
f26d5c33	54	struct PFwdPrivate {
c85623f9	55	const struct plug_function_table *fn;
f26d5c33	56	/* the above variable absolutely must be the first in this structure */
f26d5c33	57	void c; / (channel) data used by ssh.c */
6b78788a	58	void backhandle; / instance of SSH backend itself */
6b78788a	59	/* Note that backhandle need not be filled in if c is non-NULL */
f26d5c33	60	Socket s;
5471d09a	61	int throttled, throttle_override;
f26d5c33	62	int ready;
820ebe3b	63	/*
	64	* `dynamic' does double duty. It's set to 0 for an ordinary
	65	* forwarded port, and nonzero for SOCKS-style dynamic port
	66	* forwarding; but it also represents the state of the SOCKS
	67	* exchange.
	68	*/
	69	int dynamic;
	70	/*
	71	* `hostname' and `port' are the real hostname and port, once
	72	* we know what we're connecting to; they're unused for this
	73	* purpose while conducting a local SOCKS exchange, which means
	74	* we can also use them as a buffer and pointer for reading
	75	* data from the SOCKS client.
	76	*/
fab893b6	77	char hostname[256+8];
820ebe3b	78	int port;
	79	/*
	80	* When doing dynamic port forwarding, we can receive
	81	* connection data before we are actually able to send it; so
	82	* we may have to temporarily hold some in a dynamically
	83	* allocated buffer here.
	84	*/
	85	void *buffer;
	86	int buflen;
f26d5c33	87	};
f26d5c33	88
f26d5c33	89	static int pfd_closing(Plug plug, char *error_msg, int error_code,
	90	int calling_back)
	91	{
	92	struct PFwdPrivate pr = (struct PFwdPrivate ) plug;
	93
	94	/*
	95	* We have no way to communicate down the forwarded connection,
	96	* so if an error occurred on the socket, we just ignore it
	97	* and treat it like a proper close.
	98	*/
820ebe3b	99	if (pr->c)
820ebe3b	100	sshfwd_close(pr->c);
f26d5c33	101	pfd_close(pr->s);
	102	return 1;
	103	}
	104
	105	static int pfd_receive(Plug plug, int urgent, char *data, int len)
	106	{
	107	struct PFwdPrivate pr = (struct PFwdPrivate ) plug;
820ebe3b	108	if (pr->dynamic) {
	109	while (len--) {
	110	if (pr->port >= lenof(pr->hostname)) {
	111	if ((pr->dynamic >> 12) == 4) {
	112	/* Send back a SOCKS 4 error before closing. */
	113	char data[8];
	114	memset(data, 0, sizeof(data));
	115	data[1] = 91; /* generic `request rejected' */
	116	sk_write(pr->s, data, 8);
	117	}
	118	pfd_close(pr->s);
	119	return 1;
	120	}
	121	pr->hostname[pr->port++] = *data++;
	122
	123	/*
	124	* Now check what's in the buffer to see if it's a
	125	* valid and complete message in the SOCKS exchange.
	126	*/
	127	if ((pr->dynamic == 1 \|\| (pr->dynamic >> 12) == 4) &&
	128	pr->hostname[0] == 4) {
	129	/*
	130	* SOCKS 4.
	131	*/
	132	if (pr->dynamic == 1)
	133	pr->dynamic = 0x4000;
	134	if (pr->port < 2) continue;/* don't have command code yet */
	135	if (pr->hostname[1] != 1) {
	136	/* Send back a SOCKS 4 error before closing. */
	137	char data[8];
	138	memset(data, 0, sizeof(data));
	139	data[1] = 91; /* generic `request rejected' */
	140	sk_write(pr->s, data, 8);
	141	pfd_close(pr->s);
	142	return 1;
	143	}
	144	if (pr->port < 8) continue; /* haven't started username */
	145	if (pr->hostname[pr->port-1] != 0)
	146	continue; /* haven't _finished_ username */
	147	/*
	148	* Now we have a full SOCKS 4 request. Check it to
	149	* see if it's a SOCKS 4A request.
	150	*/
	151	if (pr->hostname[4] == 0 && pr->hostname[5] == 0 &&
	152	pr->hostname[6] == 0 && pr->hostname[7] != 0) {
	153	/*
	154	* It's SOCKS 4A. So if we haven't yet
	155	* collected the host name, we should continue
	156	* waiting for data in order to do so; if we
	157	* have, we can go ahead.
	158	*/
	159	int len;
	160	if (pr->dynamic == 0x4000) {
	161	pr->dynamic = 0x4001;
fab893b6	162	pr->port = 8; /* reset buffer to overwrite name */
820ebe3b	163	continue;
	164	}
	165	pr->hostname[0] = 0; /* reply version code */
	166	pr->hostname[1] = 90; /* request granted */
	167	sk_write(pr->s, pr->hostname, 8);
fab893b6	168	len= pr->port;
820ebe3b	169	pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
fab893b6	170	memmove(pr->hostname, pr->hostname + 8, len);
820ebe3b	171	goto connect;
	172	} else {
	173	/*
	174	* It's SOCKS 4, which means we should format
	175	* the IP address into the hostname string and
	176	* then just go.
	177	*/
	178	pr->hostname[0] = 0; /* reply version code */
	179	pr->hostname[1] = 90; /* request granted */
	180	sk_write(pr->s, pr->hostname, 8);
	181	pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
	182	sprintf(pr->hostname, "%d.%d.%d.%d",
	183	(unsigned char)pr->hostname[4],
	184	(unsigned char)pr->hostname[5],
	185	(unsigned char)pr->hostname[6],
	186	(unsigned char)pr->hostname[7]);
	187	goto connect;
	188	}
	189	}
	190
	191	if ((pr->dynamic == 1 \|\| (pr->dynamic >> 12) == 5) &&
	192	pr->hostname[0] == 5) {
	193	/*
	194	* SOCKS 5.
	195	*/
	196	if (pr->dynamic == 1)
	197	pr->dynamic = 0x5000;
	198
	199	if (pr->dynamic == 0x5000) {
	200	int i, method;
	201	char data[2];
	202	/*
	203	* We're receiving a set of method identifiers.
	204	*/
	205	if (pr->port < 2) continue;/* no method count yet */
	206	if (pr->port < 2 + (unsigned char)pr->hostname[1])
	207	continue; /* no methods yet */
	208	method = 0xFF; /* invalid */
	209	for (i = 0; i < (unsigned char)pr->hostname[1]; i++)
	210	if (pr->hostname[2+i] == 0) {
	211	method = 0;/* no auth */
	212	break;
	213	}
	214	data[0] = 5;
	215	data[1] = method;
	216	sk_write(pr->s, data, 2);
	217	pr->dynamic = 0x5001;
	218	pr->port = 0; /* re-empty the buffer */
	219	continue;
	220	}
	221
	222	if (pr->dynamic == 0x5001) {
	223	int atype, alen;
	224	if (pr->port < 6) continue;
	225	atype = (unsigned char)pr->hostname[3];
	226	if (atype == 1) /* IPv4 address */
	227	alen = 4;
	228	if (atype == 4) /* IPv6 address */
	229	alen = 16;
	230	if (atype == 3) /* domain name has leading length */
	231	alen = 1 + (unsigned char)pr->hostname[4];
	232	if (pr->port < 6 + alen) continue;
	233	if (pr->hostname[1] != 1 \|\| pr->hostname[2] != 0) {
	234	pr->hostname[1] = 1; /* generic failure */
235	pr->hostname[2] = 0; /* reserved */
236	sk_write(pr->s, pr->hostname, pr->port);
237	pfd_close(pr->s);
238	return 1;
239	}
240	/*
241	* Now we have a viable connect request. Switch
242	* on atype.
243	*/
244	pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen);
245	if (atype == 1) {
246	pr->hostname[1] = 0; /* succeeded */
247	sk_write(pr->s, pr->hostname, alen + 6);
248	sprintf(pr->hostname, "%d.%d.%d.%d",
249	(unsigned char)pr->hostname[4],
250	(unsigned char)pr->hostname[5],
251	(unsigned char)pr->hostname[6],
252	(unsigned char)pr->hostname[7]);
253	goto connect;
254	} else if (atype == 3) {
255	pr->hostname[1] = 0; /* succeeded */
256	sk_write(pr->s, pr->hostname, alen + 6);
257	memmove(pr->hostname, pr->hostname + 5, alen-1);
258	pr->hostname[alen-1] = '\0';
259	goto connect;
260	} else {
261	/*
262	* Unknown address type. (FIXME: support IPv6!)
263	*/
264	pr->hostname[1] = 8; /* atype not supported */
265	sk_write(pr->s, pr->hostname, pr->port);
266	pfd_close(pr->s);
267	return 1;
268	}
269	}
270	}
271
272	/*
273	* If we get here without either having done `continue'
274	* or `goto connect', it must be because there is no
275	* sensible interpretation of what's in our buffer. So
276	* close the connection rudely.
277	*/
278	pfd_close(pr->s);
279	return 1;
280	}
281	return 1;
282
283	/*
284	* We come here when we're ready to make an actual
285	* connection.
286	*/
287	connect:
288
289	pr->c = new_sock_channel(pr->backhandle, pr->s);
290	if (pr->c == NULL) {
291	pfd_close(pr->s);
292	return 1;
293	} else {
294	/* asks to forward to the specified host/port for this */
295	ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
296	}
297	pr->dynamic = 0;
298
299	/*
300	* Now freeze the socket until the SSH server confirms the
301	* connection.
302	*/
303	sk_set_frozen(pr->s, 1);
304	/*
305	* If there's any data remaining in our current buffer,
306	* save it to be sent on pfd_confirm().
307	*/
308	if (len > 0) {
309	pr->buffer = snewn(len, char);
310	memcpy(pr->buffer, data, len);
311	pr->buflen = len;
312	}
313	}
5471d09a	314	if (pr->ready) {
	315	if (sshfwd_write(pr->c, data, len) > 0) {
	316	pr->throttled = 1;
	317	sk_set_frozen(pr->s, 1);
	318	}
	319	}
f26d5c33	320	return 1;
	321	}
	322
5471d09a	323	static void pfd_sent(Plug plug, int bufsize)
	324	{
	325	struct PFwdPrivate pr = (struct PFwdPrivate ) plug;
	326
820ebe3b	327	if (pr->c)
820ebe3b	328	sshfwd_unthrottle(pr->c, bufsize);
5471d09a	329	}
5471d09a	330
f26d5c33	331	/*
	332	* Called when receiving a PORT OPEN from the server
	333	*/
e8fa8f62	334	char pfd_newconnect(Socket s, char hostname, int port, void c,
e8fa8f62	335	const Config *cfg)
f26d5c33	336	{
c85623f9	337	static const struct plug_function_table fn_table = {
f26d5c33	338	pfd_closing,
f26d5c33	339	pfd_receive,
5471d09a	340	pfd_sent,
f26d5c33	341	NULL
	342	};
	343
	344	SockAddr addr;
	345	char err, dummy_realhost;
	346	struct PFwdPrivate *pr;
	347
	348	/*
	349	* Try to find host.
	350	*/
e8fa8f62	351	addr = name_lookup(hostname, port, &dummy_realhost, cfg);
808c3834	352	if ((err = sk_addr_error(addr)) != NULL)
f26d5c33	353	return err;
	354
	355	/*
	356	* Open socket.
	357	*/
3d88e64d	358	pr = snew(struct PFwdPrivate);
820ebe3b	359	pr->buffer = NULL;
f26d5c33	360	pr->fn = &fn_table;
5471d09a	361	pr->throttled = pr->throttle_override = 0;
f26d5c33	362	pr->ready = 1;
f26d5c33	363	pr->c = c;
6b78788a	364	pr->backhandle = NULL; /* we shouldn't need this */
f26d5c33	365
e8fa8f62	366	pr->s = *s = new_connection(addr, dummy_realhost, port,
e8fa8f62	367	0, 1, 0, (Plug) pr, cfg);
808c3834	368	if ((err = sk_socket_error(*s)) != NULL) {
f26d5c33	369	sfree(pr);
	370	return err;
	371	}
	372
	373	sk_set_private_ptr(*s, pr);
	374	sk_addr_free(addr);
	375	return NULL;
	376	}
	377
	378	/*
	379	called when someone connects to the local port
	380	*/
	381
bcce45ed	382	static int pfd_accepting(Plug p, void *sock)
f26d5c33	383	{
c85623f9	384	static const struct plug_function_table fn_table = {
f26d5c33	385	pfd_closing,
f26d5c33	386	pfd_receive,
5471d09a	387	pfd_sent,
f26d5c33	388	NULL
	389	};
	390	struct PFwdPrivate pr, org;
f26d5c33	391	Socket s;
	392	char *err;
	393
f26d5c33	394	org = (struct PFwdPrivate *)p;
3d88e64d	395	pr = snew(struct PFwdPrivate);
820ebe3b	396	pr->buffer = NULL;
f26d5c33	397	pr->fn = &fn_table;
	398
	399	pr->c = NULL;
6b78788a	400	pr->backhandle = org->backhandle;
f26d5c33	401
f26d5c33	402	pr->s = s = sk_register(sock, (Plug) pr);
808c3834	403	if ((err = sk_socket_error(s)) != NULL) {
f26d5c33	404	sfree(pr);
	405	return err != NULL;
	406	}
	407
820ebe3b	408	sk_set_private_ptr(s, pr);
f26d5c33	409
5471d09a	410	pr->throttled = pr->throttle_override = 0;
f26d5c33	411	pr->ready = 0;
f26d5c33	412
820ebe3b	413	if (org->dynamic) {
	414	pr->dynamic = 1;
	415	pr->port = 0; /* hostname buffer is so far empty */
	416	sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */
f26d5c33	417	} else {
820ebe3b	418	strcpy(pr->hostname, org->hostname);
	419	pr->port = org->port;
	420	pr->c = new_sock_channel(org->backhandle, s);
	421
	422	if (pr->c == NULL) {
	423	sfree(pr);
	424	return 1;
	425	} else {
	426	/* asks to forward to the specified host/port for this */
	427	ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
	428	}
f26d5c33	429	}
	430
	431	return 0;
	432	}
	433
	434
	435	/* Add a new forwarding from port -> desthost:destport
6ee9b735	436	sets up a listener on the local machine on (srcaddr:)port
f26d5c33	437	*/
6ee9b735	438	char pfd_addforward(char desthost, int destport, char *srcaddr, int port,
e8fa8f62	439	void backhandle, const Config cfg)
f26d5c33	440	{
c85623f9	441	static const struct plug_function_table fn_table = {
f26d5c33	442	pfd_closing,
5471d09a	443	pfd_receive, /* should not happen... */
5471d09a	444	pfd_sent, /* also should not happen */
f26d5c33	445	pfd_accepting
	446	};
	447
	448	char *err;
	449	struct PFwdPrivate *pr;
	450	Socket s;
	451
	452	/*
	453	* Open socket.
	454	*/
3d88e64d	455	pr = snew(struct PFwdPrivate);
820ebe3b	456	pr->buffer = NULL;
f26d5c33	457	pr->fn = &fn_table;
f26d5c33	458	pr->c = NULL;
820ebe3b	459	if (desthost) {
	460	strcpy(pr->hostname, desthost);
	461	pr->port = destport;
	462	pr->dynamic = 0;
	463	} else
	464	pr->dynamic = 1;
5471d09a	465	pr->throttled = pr->throttle_override = 0;
f26d5c33	466	pr->ready = 0;
6b78788a	467	pr->backhandle = backhandle;
f26d5c33	468
e8fa8f62	469	pr->s = s = new_listener(srcaddr, port, (Plug) pr,
e8fa8f62	470	!cfg->lport_acceptall, cfg);
808c3834	471	if ((err = sk_socket_error(s)) != NULL) {
f26d5c33	472	sfree(pr);
	473	return err;
	474	}
	475
	476	sk_set_private_ptr(s, pr);
	477
	478	return NULL;
	479	}
	480
	481	void pfd_close(Socket s)
	482	{
	483	struct PFwdPrivate *pr;
	484
	485	if (!s)
	486	return;
	487
	488	pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
	489
820ebe3b	490	sfree(pr->buffer);
f26d5c33	491	sfree(pr);
	492
	493	sk_close(s);
	494	}
	495
5471d09a	496	void pfd_unthrottle(Socket s)
	497	{
	498	struct PFwdPrivate *pr;
	499	if (!s)
	500	return;
	501	pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
	502
	503	pr->throttled = 0;
	504	sk_set_frozen(s, pr->throttled \|\| pr->throttle_override);
	505	}
	506
	507	void pfd_override_throttle(Socket s, int enable)
	508	{
	509	struct PFwdPrivate *pr;
	510	if (!s)
	511	return;
	512	pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
	513
	514	pr->throttle_override = enable;
	515	sk_set_frozen(s, pr->throttled \|\| pr->throttle_override);
	516	}
	517
f26d5c33	518	/*
	519	* Called to send data down the raw connection.
	520	*/
5471d09a	521	int pfd_send(Socket s, char *data, int len)
f26d5c33	522	{
f26d5c33	523	if (s == NULL)
5471d09a	524	return 0;
5471d09a	525	return sk_write(s, data, len);
f26d5c33	526	}
	527
	528
	529	void pfd_confirm(Socket s)
	530	{
5f2e19fc	531	struct PFwdPrivate *pr;
f26d5c33	532
	533	if (s == NULL)
	534	return;
	535
5f2e19fc	536	pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
f26d5c33	537	pr->ready = 1;
	538	sk_set_frozen(s, 0);
	539	sk_write(s, NULL, 0);
820ebe3b	540	if (pr->buffer) {
	541	sshfwd_write(pr->c, pr->buffer, pr->buflen);
	542	sfree(pr->buffer);
	543	pr->buffer = NULL;
	544	}
f26d5c33	545	}