xref: /src/sys/external/bsd/ipf/netinet/ip_proxy.c

/*	$NetBSD: ip_proxy.c,v 1.2 2012/03/23 20:39:50 christos Exp $	*/

/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 */
#if defined(KERNEL) || defined(_KERNEL)
# undef KERNEL
# undef _KERNEL
# define        KERNEL	1
# define        _KERNEL	1
#endif
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/file.h>
#if !defined(AIX)
# include <sys/fcntl.h>
#endif
#if !defined(_KERNEL) && !defined(__KERNEL__)
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
# include <ctype.h>
# define _KERNEL
# ifdef __OpenBSD__
struct file;
# endif
# include <sys/uio.h>
# undef _KERNEL
#endif
#if !defined(linux)
# include <sys/protosw.h>
#endif
#include <sys/socket.h>
#if defined(_KERNEL)
# if !defined(__NetBSD__) && !defined(sun) && !defined(__osf__) && \
     !defined(__OpenBSD__) && !defined(__hpux) && !defined(__sgi) && \
     !defined(AIX)
#  include <sys/ctype.h>
# endif
# include <sys/systm.h>
# if !defined(__SVR4) && !defined(__svr4__)
#  include <sys/mbuf.h>
# endif
#endif
#if defined(_KERNEL) && (__FreeBSD_version >= 220000)
# include <sys/filio.h>
# include <sys/fcntl.h>
#else
# include <sys/ioctl.h>
#endif
#if defined(__SVR4) || defined(__svr4__)
# include <sys/byteorder.h>
# ifdef _KERNEL
#  include <sys/dditypes.h>
# endif
# include <sys/stream.h>
# include <sys/kmem.h>
#endif
#if __FreeBSD__ > 2
# include <sys/queue.h>
#endif
#include <net/if.h>
#ifdef sun
# include <net/af.h>
#endif
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifndef linux
# include <netinet/ip_var.h>
#endif
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include "netinet/ip_compat.h"
#include <netinet/tcpip.h>
#include "netinet/ip_fil.h"
#include "netinet/ip_nat.h"
#include "netinet/ip_state.h"
#include "netinet/ip_proxy.h"
#if (__FreeBSD_version >= 300000)
# include <sys/malloc.h>
#endif

/* END OF INCLUDES */

#include "netinet/ip_dns_pxy.c"
#include "netinet/ip_ftp_pxy.c"
#include "netinet/ip_tftp_pxy.c"
#include "netinet/ip_rcmd_pxy.c"
#include "netinet/ip_pptp_pxy.c"
#if defined(_KERNEL)
# include "netinet/ip_irc_pxy.c"
# include "netinet/ip_raudio_pxy.c"
# include "netinet/ip_h323_pxy.c"
# include "netinet/ip_netbios_pxy.c"
#endif
#include "netinet/ip_ipsec_pxy.c"
#include "netinet/ip_rpcb_pxy.c"

#if !defined(lint)
#if defined(__NetBSD__)
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip_proxy.c,v 1.2 2012/03/23 20:39:50 christos Exp $");
#else
static const char rcsid[] = "@(#)Id: ip_proxy.c,v 2.102.2.7 2012/01/29 05:30:36 darrenr Exp";
#endif
#endif

#define	AP_SESS_SIZE	53

static int ipf_proxy_fixseqack(fr_info_t *, ip_t *, ap_session_t *, int );
static aproxy_t *ipf_proxy_create_clone(ipf_main_softc_t *, aproxy_t *);

typedef struct ipf_proxy_softc_s {
	int		ips_proxy_debug;
	int		ips_proxy_session_size;
	ap_session_t	**ips_sess_tab;
	ap_session_t	*ips_sess_list;
	aproxy_t	*ips_proxies;
	int		ips_init_run;
	ipftuneable_t	*ipf_proxy_tune;
} ipf_proxy_softc_t;

static ipftuneable_t ipf_proxy_tuneables[] = {
	{ { (void *)offsetof(ipf_proxy_softc_t, ips_proxy_debug) },
		"ips_proxy_debug",	0,	10,
		stsizeof(ipf_proxy_softc_t, ips_proxy_debug),
		0,	NULL,	NULL },
	{ { NULL },		NULL,			0,	0,
		0,
		0,	NULL,	NULL}
};

static	aproxy_t	*ap_proxylist = NULL;
static	aproxy_t	ips_proxies[] = {
#ifdef	IPF_FTP_PROXY
	{ NULL, NULL, "ftp", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_ftp_main_load, ipf_p_ftp_main_unload,
	  ipf_p_ftp_soft_create, ipf_p_ftp_soft_destroy,
	  NULL, NULL,
	  ipf_p_ftp_new, ipf_p_ftp_del, ipf_p_ftp_in, ipf_p_ftp_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_TFTP_PROXY
	{ NULL, NULL, "tftp", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_tftp_main_load, ipf_p_tftp_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_tftp_new, NULL, ipf_p_tftp_in, ipf_p_tftp_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_IRC_PROXY
	{ NULL, NULL, "irc", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_irc_main_load, ipf_p_irc_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_irc_new, NULL, NULL, ipf_p_irc_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_RCMD_PROXY
	{ NULL, NULL, "rcmd", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_rcmd_main_load, ipf_p_rcmd_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_rcmd_new, ipf_p_rcmd_del,
	  ipf_p_rcmd_in, ipf_p_rcmd_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_RAUDIO_PROXY
	{ NULL, NULL, "raudio", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_raudio_main_load, ipf_p_raudio_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_raudio_new, NULL, ipf_p_raudio_in, ipf_p_raudio_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_MSNRPC_PROXY
	{ NULL, NULL, "msnrpc", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_msnrpc_init, ipf_p_msnrpc_fini,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_msnrpc_new, NULL, ipf_p_msnrpc_in, ipf_p_msnrpc_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_NETBIOS_PROXY
	{ NULL, NULL, "netbios", (char)IPPROTO_UDP, 0, 0, 0,
	  ipf_p_netbios_main_load, ipf_p_netbios_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  NULL, NULL, NULL, ipf_p_netbios_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_IPSEC_PROXY
	{ NULL, NULL, "ipsec", (char)IPPROTO_UDP, 0, 0, 0,
	  NULL, NULL,
	  ipf_p_ipsec_soft_create, ipf_p_ipsec_soft_destroy,
	  ipf_p_ipsec_soft_init, ipf_p_ipsec_soft_fini,
	  ipf_p_ipsec_new, ipf_p_ipsec_del,
	  ipf_p_ipsec_inout, ipf_p_ipsec_inout, ipf_p_ipsec_match,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_DNS_PROXY
	{ NULL, NULL, "dns", (char)IPPROTO_UDP, 0, 0, 0,
	  NULL, NULL,
	  ipf_p_dns_soft_create, ipf_p_dns_soft_destroy,
	  NULL, NULL,
	  ipf_p_dns_new, ipf_p_ipsec_del,
	  ipf_p_dns_inout, ipf_p_dns_inout, ipf_p_dns_match,
	  ipf_p_dns_ctl, NULL, NULL, NULL },
#endif
#ifdef	IPF_PPTP_PROXY
	{ NULL, NULL, "pptp", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_pptp_main_load, ipf_p_pptp_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_pptp_new, ipf_p_pptp_del,
	  ipf_p_pptp_inout, ipf_p_pptp_inout, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef  IPF_H323_PROXY
	{ NULL, NULL, "h323", (char)IPPROTO_TCP, 0, 0, 0,
	  ipf_p_h323_main_load, ipf_p_h323_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_h323_new, ipf_p_h323_del,
	  ipf_p_h323_in, NULL, NULL,
	  NULL, NULL, NULL, NULL },
	{ NULL, NULL, "h245", (char)IPPROTO_TCP, 0, 0, 0, NULL, NULL,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_h245_new, NULL,
	  NULL, ipf_p_h245_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
#ifdef	IPF_RPCB_PROXY
# ifndef _KERNEL
	{ NULL, NULL, "rpcbt", (char)IPPROTO_TCP, 0, 0, 0,
	  NULL, NULL,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_rpcb_new, ipf_p_rpcb_del,
	  ipf_p_rpcb_in, ipf_p_rpcb_out, NULL,
	  NULL, NULL, NULL, NULL },
# endif
	{ NULL, NULL, "rpcbu", (char)IPPROTO_UDP, 0, 0, 0,
	  ipf_p_rpcb_main_load, ipf_p_rpcb_main_unload,
	  NULL, NULL,
	  NULL, NULL,
	  ipf_p_rpcb_new, ipf_p_rpcb_del,
	  ipf_p_rpcb_in, ipf_p_rpcb_out, NULL,
	  NULL, NULL, NULL, NULL },
#endif
	{ NULL, NULL, "", '\0', 0, 0, 0,
	  NULL, NULL,
	  NULL, NULL,
	  NULL, NULL,
	  NULL, NULL,
	  NULL, NULL, NULL,
	  NULL, NULL, NULL, NULL }
};


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_init                                              */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* Initialise hook for kernel application proxies.                          */
/* Call the initialise routine for all the compiled in kernel proxies.      */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_main_load(void)
{
	aproxy_t *ap;

	for (ap = ips_proxies; ap->apr_p; ap++) {
		if (ap->apr_load != NULL)
			(*ap->apr_load)();
	}
	return 0;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_unload                                            */
/* Returns:     Nil                                                         */
/* Parameters:  Nil                                                         */
/*                                                                          */
/* Unload hook for kernel application proxies.                              */
/* Call the finialise routine for all the compiled in kernel proxies.       */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_main_unload(void)
{
	aproxy_t *ap;

	for (ap = ips_proxies; ap->apr_p; ap++)
		if (ap->apr_unload != NULL)
			(*ap->apr_unload)();
	for (ap = ap_proxylist; ap; ap = ap->apr_next)
		if (ap->apr_unload != NULL)
			(*ap->apr_unload)();

	return 0;
}


void *
ipf_proxy_soft_create(ipf_main_softc_t *softc)
{
	ipf_proxy_softc_t *softp;
	aproxy_t *last;
	aproxy_t *apn;
	aproxy_t *ap;

	KMALLOC(softp, ipf_proxy_softc_t *);
	if (softp == NULL)
		return softp;

	bzero((char *)softp, sizeof(*softp));

#if defined(_KERNEL)
	softp->ips_proxy_debug = 0;
#else
	softp->ips_proxy_debug = 2;
#endif
	softp->ips_proxy_session_size = AP_SESS_SIZE;

	softp->ipf_proxy_tune = ipf_tune_array_copy(softp,
						    sizeof(ipf_proxy_tuneables),
						    ipf_proxy_tuneables);
	if (softp->ipf_proxy_tune == NULL) {
		ipf_proxy_soft_destroy(softc, softp);
		return NULL;
	}
	if (ipf_tune_array_link(softc, softp->ipf_proxy_tune) == -1) {
		ipf_proxy_soft_destroy(softc, softp);
		return NULL;
	}

	last = NULL;
	for (ap = ips_proxies; ap->apr_p; ap++) {
		apn = ipf_proxy_create_clone(softc, ap);
		if (apn == NULL)
			goto failed;
		if (last != NULL)
			last->apr_next = apn;
		else
			softp->ips_proxies = apn;
		last = apn;
	}
	for (ap = ips_proxies; ap != NULL; ap = ap->apr_next) {
		apn = ipf_proxy_create_clone(softc, ap);
		if (apn == NULL)
			goto failed;
		if (last != NULL)
			last->apr_next = apn;
		else
			softp->ips_proxies = apn;
		last = apn;
	}

	return softp;
failed:
	ipf_proxy_soft_destroy(softc, softp);
	return NULL;
}


static aproxy_t *
ipf_proxy_create_clone(ipf_main_softc_t *softc, aproxy_t *orig)
{
	aproxy_t *apn;

	KMALLOC(apn, aproxy_t *);
	if (apn == NULL)
		return NULL;

	bcopy((char *)orig, (char *)apn, sizeof(*apn));
	apn->apr_next = NULL;
	apn->apr_soft = NULL;

	if (apn->apr_create != NULL) {
		apn->apr_soft = (*apn->apr_create)(softc);
		if (apn->apr_soft == NULL) {
			KFREE(apn);
			return NULL;
		}
	}

	apn->apr_parent = orig;
	orig->apr_clones++;

	return apn;
}


int
ipf_proxy_soft_init(ipf_main_softc_t *softc, void *arg)
{
	ipf_proxy_softc_t *softp;
	aproxy_t *ap;
	u_int size;
	int err;

	softp = arg;
	size = softp->ips_proxy_session_size * sizeof(ap_session_t *);

	KMALLOCS(softp->ips_sess_tab, ap_session_t **, size);

	if (softp->ips_sess_tab == NULL)
		return -1;

	bzero(softp->ips_sess_tab, size);

	for (ap = softp->ips_proxies; ap != NULL; ap = ap->apr_next) {
		if (ap->apr_init != NULL) {
			err = (*ap->apr_init)(softc, ap->apr_soft);
			if (err != 0)
				return -2;
		}
	}
	softp->ips_init_run = 1;

	return 0;
}


int
ipf_proxy_soft_fini(ipf_main_softc_t *softc, void *arg)
{
	ipf_proxy_softc_t *softp = arg;
	aproxy_t *ap;

	for (ap = softp->ips_proxies; ap != NULL; ap = ap->apr_next) {
		if (ap->apr_fini != NULL) {
			(*ap->apr_fini)(softc, ap->apr_soft);
		}
	}

	if (softp->ips_sess_tab != NULL) {
		KFREES(softp->ips_sess_tab,
		       softp->ips_proxy_session_size * sizeof(ap_session_t *));
		softp->ips_sess_tab = NULL;
	}
	softp->ips_init_run = 0;

	return 0;
}


void
ipf_proxy_soft_destroy(ipf_main_softc_t *softc, void *arg)
{
	ipf_proxy_softc_t *softp = arg;
	aproxy_t *ap;

	while ((ap = softp->ips_proxies) != NULL) {
		softp->ips_proxies = ap->apr_next;
		if (ap->apr_destroy != NULL)
			(*ap->apr_destroy)(softc, ap->apr_soft);
		ap->apr_parent->apr_clones--;
		KFREE(ap);
	}

	if (softp->ipf_proxy_tune != NULL) {
                ipf_tune_array_unlink(softc, softp->ipf_proxy_tune);
                KFREES(softp->ipf_proxy_tune, sizeof(ipf_proxy_tuneables));
                softp->ipf_proxy_tune = NULL;
	}

	KFREE(softp);
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_flush                                             */
/* Returns:     Nil                                                         */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* ------------------------------------------------------------------------ */
void
ipf_proxy_flush(void *arg, int how)
{
	ipf_proxy_softc_t *softp = arg;
	aproxy_t *ap;

	switch (how)
	{
	case 0 :
		for (ap = softp->ips_proxies; ap; ap = ap->apr_next)
			if (ap->apr_flush != NULL)
				(*ap->apr_flush)(ap, how);
		break;
	case 1 :
		for (ap = softp->ips_proxies; ap; ap = ap->apr_next)
			if (ap->apr_clear != NULL)
				(*ap->apr_clear)(ap);
		break;
	default :
		break;
	}
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_add                                               */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  ap(I) - pointer to proxy structure                          */
/*                                                                          */
/* Dynamically add a new kernel proxy.  Ensure that it is unique in the     */
/* collection compiled in and dynamically added.                            */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_add(void *arg, aproxy_t *ap)
{
	ipf_proxy_softc_t *softp = arg;

	aproxy_t *a;

	for (a = ips_proxies; a->apr_p; a++)
		if ((a->apr_p == ap->apr_p) &&
		    !strncmp(a->apr_label, ap->apr_label,
			     sizeof(ap->apr_label))) {
			if (softp->ips_proxy_debug > 1)
				printf("ipf_proxy_add: %s/%d present (B)\n",
				       a->apr_label, a->apr_p);
			return -1;
		}

	for (a = ap_proxylist; (a != NULL); a = a->apr_next)
		if ((a->apr_p == ap->apr_p) &&
		    !strncmp(a->apr_label, ap->apr_label,
			     sizeof(ap->apr_label))) {
			if (softp->ips_proxy_debug > 1)
				printf("ipf_proxy_add: %s/%d present (D)\n",
				       a->apr_label, a->apr_p);
			return -1;
		}
	ap->apr_next = ap_proxylist;
	ap_proxylist = ap;
	if (ap->apr_load != NULL)
		(*ap->apr_load)();
	return 0;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_ctl                                               */
/* Returns:     int - 0 == success, else error                              */
/* Parameters:  ctl(I) - pointer to proxy control structure                 */
/*                                                                          */
/* Check to see if the proxy this control request has come through for      */
/* exists, and if it does and it has a control function then invoke that    */
/* control function.                                                        */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_ctl(ipf_main_softc_t *softc, void *arg, ap_ctl_t *ctl)
{
	ipf_proxy_softc_t *softp = arg;
	aproxy_t *a;
	int error;

	a = ipf_proxy_lookup(arg, ctl->apc_p, ctl->apc_label);
	if (a == NULL) {
		if (softp->ips_proxy_debug > 1)
			printf("ipf_proxy_ctl: can't find %s/%d\n",
				ctl->apc_label, ctl->apc_p);
		IPFERROR(80001);
		error = ESRCH;
	} else if (a->apr_ctl == NULL) {
		if (softp->ips_proxy_debug > 1)
			printf("ipf_proxy_ctl: no ctl function for %s/%d\n",
				ctl->apc_label, ctl->apc_p);
		IPFERROR(80002);
		error = ENXIO;
	} else {
		error = (*a->apr_ctl)(softc, a->apr_soft, ctl);
		if ((error != 0) && (softp->ips_proxy_debug > 1))
			printf("ipf_proxy_ctl: %s/%d ctl error %d\n",
				a->apr_label, a->apr_p, error);
	}
	return error;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_del                                               */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  ap(I) - pointer to proxy structure                          */
/*                                                                          */
/* Delete a proxy that has been added dynamically from those available.     */
/* If it is in use, return 1 (do not destroy NOW), not in use 0 or -1       */
/* if it cannot be matched.                                                 */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_del(aproxy_t *ap)
{
	aproxy_t *a, **app;

	for (app = &ap_proxylist; ((a = *app) != NULL); app = &a->apr_next) {
		if (a == ap) {
			a->apr_flags |= APR_DELETE;
			if (ap->apr_ref == 0 && ap->apr_clones == 0) {
				*app = a->apr_next;
				return 0;
			}
			return 1;
		}
	}

	return -1;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_ok                                                */
/* Returns:     int - 1 == good match else not.                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_ok(fr_info_t *fin, tcphdr_t *tcp, ipnat_t *nat)
{
	aproxy_t *apr = nat->in_apr;
	u_short dport = nat->in_odport;

	if ((apr == NULL) || (apr->apr_flags & APR_DELETE) ||
	    (fin->fin_p != apr->apr_p))
		return 0;
	if ((tcp == NULL) && dport)
		return 0;
	return 1;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_ioctl                                             */
/* Returns:     int - 0 == success, else error                              */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_ioctl(ipf_main_softc_t *softc, void *data, ioctlcmd_t cmd, int mode,
    void *ctx)
{
	ap_ctl_t ctl;
	void *ptr;
	int error;

	mode = mode;	/* LINT */

	switch (cmd)
	{
	case SIOCPROXY :
		error = ipf_inobj(softc, data, NULL, &ctl, IPFOBJ_PROXYCTL);
		if (error != 0) {
			return error;
		}
		ptr = NULL;

		if (ctl.apc_dsize > 0) {
			KMALLOCS(ptr, void *, ctl.apc_dsize);
			if (ptr == NULL) {
				IPFERROR(80003);
				error = ENOMEM;
			} else {
				error = copyinptr(softc, ctl.apc_data, ptr,
						  ctl.apc_dsize);
				if (error == 0)
					ctl.apc_data = ptr;
			}
		} else {
			ctl.apc_data = NULL;
			error = 0;
		}

		if (error == 0)
			error = ipf_proxy_ctl(softc, softc->ipf_proxy_soft, &ctl);

		if ((error != 0) && (ptr != NULL)) {
			KFREES(ptr, ctl.apc_dsize);
		}
		break;

	default :
		IPFERROR(80004);
		error = EINVAL;
	}
	return error;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_match                                             */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* If a proxy has a match function, call that to do extended packet         */
/* matching.                                                                */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_match(fr_info_t *fin, nat_t *nat)
{
	ipf_main_softc_t *softc = fin->fin_main_soft;
	ipf_proxy_softc_t *softp = softc->ipf_proxy_soft;
	aproxy_t *apr;
	ipnat_t *ipn;
	int result;

	ipn = nat->nat_ptr;
	if (softp->ips_proxy_debug > 8)
		printf("ipf_proxy_match(%lx,%lx) aps %lx ptr %lx\n",
			(u_long)fin, (u_long)nat, (u_long)nat->nat_aps,
			(u_long)ipn);

	if ((fin->fin_flx & (FI_SHORT|FI_BAD)) != 0) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_match: flx 0x%x (BAD|SHORT)\n",
				fin->fin_flx);
		return -1;
	}

	apr = ipn->in_apr;
	if ((apr == NULL) || (apr->apr_flags & APR_DELETE)) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_match:apr %lx apr_flags 0x%x\n",
				(u_long)apr, apr ? apr->apr_flags : 0);
		return -1;
	}

	if (apr->apr_match != NULL) {
		result = (*apr->apr_match)(fin, nat->nat_aps, nat);
		if (result != 0) {
			if (softp->ips_proxy_debug > 4)
				printf("ipf_proxy_match: result %d\n", result);
			return -1;
		}
	}
	return 0;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_new                                               */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* Allocate a new application proxy structure and fill it in with the       */
/* relevant details.  call the init function once complete, prior to        */
/* returning.                                                               */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_new(fr_info_t *fin, nat_t *nat)
{
	ipf_main_softc_t *softc = fin->fin_main_soft;
	ipf_proxy_softc_t *softp = softc->ipf_proxy_soft;
	register ap_session_t *aps;
	aproxy_t *apr;

	if (softp->ips_proxy_debug > 8)
		printf("ipf_proxy_new(%lx,%lx) \n", (u_long)fin, (u_long)nat);

	if ((nat->nat_ptr == NULL) || (nat->nat_aps != NULL)) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_new: nat_ptr %lx nat_aps %lx\n",
				(u_long)nat->nat_ptr, (u_long)nat->nat_aps);
		return -1;
	}

	apr = nat->nat_ptr->in_apr;

	if ((apr->apr_flags & APR_DELETE) ||
	    (fin->fin_p != apr->apr_p)) {
		if (softp->ips_proxy_debug > 2)
			printf("ipf_proxy_new: apr_flags 0x%x p %d/%d\n",
				apr->apr_flags, fin->fin_p, apr->apr_p);
		return -1;
	}

	KMALLOC(aps, ap_session_t *);
	if (!aps) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_new: malloc failed (%lu)\n",
				(u_long)sizeof(ap_session_t));
		return -1;
	}

	bzero((char *)aps, sizeof(*aps));
	aps->aps_data = NULL;
	aps->aps_apr = apr;
	aps->aps_psiz = 0;
	if (apr->apr_new != NULL)
		if ((*apr->apr_new)(apr->apr_soft, fin, aps, nat) == -1) {
			if ((aps->aps_data != NULL) && (aps->aps_psiz != 0)) {
				KFREES(aps->aps_data, aps->aps_psiz);
			}
			KFREE(aps);
			if (softp->ips_proxy_debug > 2)
				printf("ipf_proxy_new: new(%lx) failed\n",
					(u_long)apr->apr_new);
			return -1;
		}
	aps->aps_nat = nat;
	aps->aps_next = softp->ips_sess_list;
	softp->ips_sess_list = aps;
	nat->nat_aps = aps;

	return 0;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_check                                             */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* Check to see if a packet should be passed through an active proxy        */
/* routine if one has been setup for it.  We don't need to check the        */
/* checksum here if IPFILTER_CKSUM is defined because if it is, a failed    */
/* check causes FI_BAD to be set.                                           */
/* ------------------------------------------------------------------------ */
int
ipf_proxy_check(fr_info_t *fin, nat_t *nat)
{
	ipf_main_softc_t *softc = fin->fin_main_soft;
	ipf_proxy_softc_t *softp = softc->ipf_proxy_soft;
#if SOLARIS && defined(_KERNEL) && (SOLARIS2 >= 6)
# if defined(ICK_VALID)
	mb_t *m;
# endif
	int dosum = 1;
#endif
	tcphdr_t *tcp = NULL;
	udphdr_t *udp = NULL;
	ap_session_t *aps;
	aproxy_t *apr;
	ip_t *ip;
	short rv;
	int err;
#if !defined(_KERNEL) || defined(MENTAT) || defined(__sgi)
	u_32_t s1, s2, sd;
#endif

	if (fin->fin_flx & FI_BAD) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_check: flx 0x%x (BAD)\n", fin->fin_flx);
		return -1;
	}

#ifndef IPFILTER_CKSUM
	if ((fin->fin_out == 0) && (ipf_checkl4sum(fin) == -1)) {
		if (softp->ips_proxy_debug > 0)
			printf("ipf_proxy_check: l4 checksum failure %d\n",
				fin->fin_p);
		if (fin->fin_p == IPPROTO_TCP)
			softc->ipf_stats[fin->fin_out].fr_tcpbad++;
		return -1;
	}
#endif

	aps = nat->nat_aps;
	if (aps != NULL) {
		/*
		 * If there is data in this packet to be proxied then try and
		 * get it all into the one buffer, else drop it.
		 */
#if defined(MENTAT) || defined(HAVE_M_PULLDOWN)
		if ((fin->fin_dlen > 0) && !(fin->fin_flx & FI_COALESCE))
			if (ipf_coalesce(fin) == -1) {
				if (softp->ips_proxy_debug > 0)
					printf("ipf_proxy_check: coalesce failed %x\n", fin->fin_flx);
				return -1;
			}
#endif
		ip = fin->fin_ip;

		switch (fin->fin_p)
		{
		case IPPROTO_TCP :
			tcp = (tcphdr_t *)fin->fin_dp;

#if SOLARIS && defined(_KERNEL) && (SOLARIS2 >= 6) && defined(ICK_VALID)
			m = fin->fin_qfm;
			if (dohwcksum && (m->b_ick_flag == ICK_VALID))
				dosum = 0;
#endif
			/*
			 * Don't bother the proxy with these...or in fact,
			 * should we free up proxy stuff when seen?
			 */
			if ((fin->fin_tcpf & TH_RST) != 0)
				break;
			/*FALLTHROUGH*/
		case IPPROTO_UDP :
			udp = (udphdr_t *)fin->fin_dp;
			break;
		default :
			break;
		}

		apr = aps->aps_apr;
		err = 0;
		if (fin->fin_out != 0) {
			if (apr->apr_outpkt != NULL)
				err = (*apr->apr_outpkt)(apr->apr_soft, fin, aps, nat);
		} else {
			if (apr->apr_inpkt != NULL)
				err = (*apr->apr_inpkt)(apr->apr_soft, fin, aps, nat);
		}

		rv = APR_EXIT(err);
		if (((softp->ips_proxy_debug > 0) && (rv != 0)) ||
		    (softp->ips_proxy_debug > 8))
			printf("ipf_proxy_check: out %d err %x rv %d\n",
				fin->fin_out, err, rv);
		if (rv == 1)
			return -1;

		if (rv == 2) {
			ipf_proxy_free(apr);
			nat->nat_aps = NULL;
			return -1;
		}

		/*
		 * If err != 0 then the data size of the packet has changed
		 * so we need to recalculate the header checksums for the
		 * packet.
		 */
#if !defined(_KERNEL) || defined(MENTAT) || defined(__sgi)
		if (err != 0) {
			short adjlen = err & 0xffff;

			s1 = LONG_SUM(fin->fin_plen - adjlen);
			s2 = LONG_SUM(fin->fin_plen);
			CALC_SUMD(s1, s2, sd);
			ipf_fix_outcksum(fin, &ip->ip_sum, sd);
		}
#endif

#ifdef INET
		/*
		 * For TCP packets, we may need to adjust the sequence and
		 * acknowledgement numbers to reflect changes in size of the
		 * data stream.
		 *
		 * For both TCP and UDP, recalculate the layer 4 checksum,
		 * regardless, as we can't tell (here) if data has been
		 * changed or not.
		 */
		if (tcp != NULL) {
			err = ipf_proxy_fixseqack(fin, ip, aps, APR_INC(err));
#if SOLARIS && defined(_KERNEL) && (SOLARIS2 >= 6)
			if (dosum)
#endif
				tcp->th_sum = fr_cksum(fin, ip,
						       IPPROTO_TCP, tcp);
		} else if ((udp != NULL) && (udp->uh_sum != 0)) {
#if SOLARIS && defined(_KERNEL) && (SOLARIS2 >= 6)
			if (dosum)
#endif
				udp->uh_sum = fr_cksum(fin, ip,
						       IPPROTO_UDP, udp);
		}
#endif
		aps->aps_bytes += fin->fin_plen;
		aps->aps_pkts++;
		return 1;
	}
	return 0;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_lookup                                            */
/* Returns:     int - -1 == error, 0 == success                             */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* Search for an proxy by the protocol it is being used with and its name.  */
/* ------------------------------------------------------------------------ */
aproxy_t *
ipf_proxy_lookup(void *arg, u_int pr, char *name)
{
	ipf_proxy_softc_t *softp = arg;
	aproxy_t *ap;

	if (softp->ips_proxy_debug > 8)
		printf("ipf_proxy_lookup(%d,%s)\n", pr, name);

	for (ap = softp->ips_proxies; ap != NULL; ap = ap->apr_next)
		if ((ap->apr_p == pr) &&
		    !strncmp(name, ap->apr_label, sizeof(ap->apr_label))) {
			ap->apr_ref++;
			return ap;
		}

	if (softp->ips_proxy_debug > 2)
		printf("ipf_proxy_lookup: failed for %d/%s\n", pr, name);
	return NULL;
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_free                                              */
/* Returns:     Nil                                                         */
/* Parameters:  ap(I) - pointer to proxy structure                          */
/*                                                                          */
/* ------------------------------------------------------------------------ */
void
ipf_proxy_free(aproxy_t *ap)
{
	ap->apr_ref--;
}


/* ------------------------------------------------------------------------ */
/* Function:    aps_free                                                    */
/* Returns:     Nil                                                         */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* Locks Held:  ipf_nat_new, ipf_nat(W)                                     */
/* ------------------------------------------------------------------------ */
void
aps_free(ipf_main_softc_t *softc, void *arg, ap_session_t *aps)
{
	ipf_proxy_softc_t *softp = arg;
	ap_session_t *a, **ap;
	aproxy_t *apr;

	if (!aps)
		return;

	for (ap = &softp->ips_sess_list; ((a = *ap) != NULL); ap = &a->aps_next)
		if (a == aps) {
			*ap = a->aps_next;
			break;
		}

	apr = aps->aps_apr;
	if ((apr != NULL) && (apr->apr_del != NULL))
		(*apr->apr_del)(softc, aps);

	if ((aps->aps_data != NULL) && (aps->aps_psiz != 0))
		KFREES(aps->aps_data, aps->aps_psiz);
	KFREE(aps);
}


/* ------------------------------------------------------------------------ */
/* Function:    ipf_proxy_fixseqack                                         */
/* Returns:     int -  2 if TCP ack/seq is changed, else 0                  */
/* Parameters:  fin(I) - pointer to packet information                      */
/*              nat(I) - pointer to current NAT session                     */
/*                                                                          */
/* ------------------------------------------------------------------------ */
static int
ipf_proxy_fixseqack(fr_info_t *fin, ip_t *ip, ap_session_t *aps, int inc)
{
	ipf_main_softc_t *softc = fin->fin_main_soft;
	ipf_proxy_softc_t *softp = softc->ipf_proxy_soft;
	int sel, ch = 0, out, nlen;
	u_32_t seq1, seq2;
	tcphdr_t *tcp;
	short inc2;

	tcp = (tcphdr_t *)fin->fin_dp;
	out = fin->fin_out;
	/*
	 * ip_len has already been adjusted by 'inc'.
	 */
	nlen = fin->fin_plen;
	nlen -= (IP_HL(ip) << 2) + (TCP_OFF(tcp) << 2);

	inc2 = inc;
	inc = (int)inc2;

	if (out != 0) {
		seq1 = (u_32_t)ntohl(tcp->th_seq);
		sel = aps->aps_sel[out];

		/* switch to other set ? */
		if ((aps->aps_seqmin[!sel] > aps->aps_seqmin[sel]) &&
		    (seq1 > aps->aps_seqmin[!sel])) {
			if (softp->ips_proxy_debug > 7)
				printf("proxy out switch set seq %d -> %d %x > %x\n",
					sel, !sel, seq1,
					aps->aps_seqmin[!sel]);
			sel = aps->aps_sel[out] = !sel;
		}

		if (aps->aps_seqoff[sel]) {
			seq2 = aps->aps_seqmin[sel] - aps->aps_seqoff[sel];
			if (seq1 > seq2) {
				seq2 = aps->aps_seqoff[sel];
				seq1 += seq2;
				tcp->th_seq = htonl(seq1);
				ch = 1;
			}
		}

		if (inc && (seq1 > aps->aps_seqmin[!sel])) {
			aps->aps_seqmin[sel] = seq1 + nlen - 1;
			aps->aps_seqoff[sel] = aps->aps_seqoff[sel] + inc;
			if (softp->ips_proxy_debug > 7)
				printf("proxy seq set %d at %x to %d + %d\n",
					sel, aps->aps_seqmin[sel],
					aps->aps_seqoff[sel], inc);
		}

		/***/

		seq1 = ntohl(tcp->th_ack);
		sel = aps->aps_sel[1 - out];

		/* switch to other set ? */
		if ((aps->aps_ackmin[!sel] > aps->aps_ackmin[sel]) &&
		    (seq1 > aps->aps_ackmin[!sel])) {
			if (softp->ips_proxy_debug > 7)
				printf("proxy out switch set ack %d -> %d %x > %x\n",
					sel, !sel, seq1,
					aps->aps_ackmin[!sel]);
			sel = aps->aps_sel[1 - out] = !sel;
		}

		if (aps->aps_ackoff[sel] && (seq1 > aps->aps_ackmin[sel])) {
			seq2 = aps->aps_ackoff[sel];
			tcp->th_ack = htonl(seq1 - seq2);
			ch = 1;
		}
	} else {
		seq1 = ntohl(tcp->th_seq);
		sel = aps->aps_sel[out];

		/* switch to other set ? */
		if ((aps->aps_ackmin[!sel] > aps->aps_ackmin[sel]) &&
		    (seq1 > aps->aps_ackmin[!sel])) {
			if (softp->ips_proxy_debug > 7)
				printf("proxy in switch set ack %d -> %d %x > %x\n",
					sel, !sel, seq1, aps->aps_ackmin[!sel]);
			sel = aps->aps_sel[out] = !sel;
		}

		if (aps->aps_ackoff[sel]) {
			seq2 = aps->aps_ackmin[sel] - aps->aps_ackoff[sel];
			if (seq1 > seq2) {
				seq2 = aps->aps_ackoff[sel];
				seq1 += seq2;
				tcp->th_seq = htonl(seq1);
				ch = 1;
			}
		}

		if (inc && (seq1 > aps->aps_ackmin[!sel])) {
			aps->aps_ackmin[!sel] = seq1 + nlen - 1;
			aps->aps_ackoff[!sel] = aps->aps_ackoff[sel] + inc;

			if (softp->ips_proxy_debug > 7)
				printf("proxy ack set %d at %x to %d + %d\n",
					!sel, aps->aps_seqmin[!sel],
					aps->aps_seqoff[sel], inc);
		}

		/***/

		seq1 = ntohl(tcp->th_ack);
		sel = aps->aps_sel[1 - out];

		/* switch to other set ? */
		if ((aps->aps_seqmin[!sel] > aps->aps_seqmin[sel]) &&
		    (seq1 > aps->aps_seqmin[!sel])) {
			if (softp->ips_proxy_debug > 7)
				printf("proxy in switch set seq %d -> %d %x > %x\n",
					sel, !sel, seq1, aps->aps_seqmin[!sel]);
			sel = aps->aps_sel[1 - out] = !sel;
		}

		if (aps->aps_seqoff[sel] != 0) {
			if (softp->ips_proxy_debug > 7)
				printf("sel %d seqoff %d seq1 %x seqmin %x\n",
					sel, aps->aps_seqoff[sel], seq1,
					aps->aps_seqmin[sel]);
			if (seq1 > aps->aps_seqmin[sel]) {
				seq2 = aps->aps_seqoff[sel];
				tcp->th_ack = htonl(seq1 - seq2);
				ch = 1;
			}
		}
	}

	if (softp->ips_proxy_debug > 8)
		printf("ipf_proxy_fixseqack: seq %x ack %x\n",
			(u_32_t)ntohl(tcp->th_seq), (u_32_t)ntohl(tcp->th_ack));
	return ch ? 2 : 0;
}