//
// based on source code from http://www.ols.es/exim/dlext/ by David Saez <david@ols.es>,
// and kas_exim.c from KAS 3.0.242 by Kaspersky Lab
//
//      warn    set acl_m0      = ${dlfunc{/usr/local/libexec/exim/exim-dlfunc.so}{kas3}\
//                              {tcp:127.0.0.1:2277}{defer_ok}{$qualify_domain}}
//

//#include "local_scan.h"
#include "exim.h"

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <fcntl.h>
#include <sys/types.h>
#include <syslog.h>
#include <sys/stat.h>
#include <errno.h>

#include "spamtest.h"
#include "msgstore.h"

#ifndef WITH_CONTENT_SCAN
extern uschar *tod_stamp(int);
//extern uschar *spool_directory;
#endif

/* Default values for configuration options */
#define KAS_CONNECT_TIMEOUT             60000
#define KAS_DEFAULT_DOMAIN              ""
#define KAS_DEFER_OK                    0
#define KAS_DATA_TIMEOUT                60000
#define KAS_CONNECT_TO                  "tcp:127.0.0.1:2277"

int check_results(spamtest_session_t *s, spamtest_status_t *status, int *res, uschar **return_text);
int proceed_accept(spamtest_status_t *status, uschar **return_text);

//-------------------------------------------------------------------------

int kas3(uschar **yield, int argc, uschar *argv[]) {
    char	*arg_socket_addr;
    char	*arg_defer_ok;
    char	*arg_default_domain;
    int		defer_ok;
    char	default_domain[64] = KAS_DEFAULT_DOMAIN;
    spamtest_session_t s;
    int		spamtest_session_flag = 0;
    spamtest_status_t *status = NULL;
    int		errorcode;
    uschar      *sender_address;
    uschar      *sender_host_address;
    int		rcpt_sent = 0;
    unsigned long cnt = 0;
    int		totalcnt = 0;
    int		i;
    int		res = 0;
    uschar	buf[32600];
    char	*ctmp;
    FILE	*mbox_file = NULL;
    uschar      *address;
#ifdef WITH_CONTENT_SCAN
    unsigned long mbox_size;
    int		mbox_delimiter_skiped = 0;
    uschar	*p;
#else
    header_line *my_headerlist;
    uschar	mbox_path[512];
#endif

    arg_socket_addr = argv[0];
    arg_defer_ok = argv[1];
    arg_default_domain = argv[2];

    if (argc < 2) {
	defer_ok = KAS_DEFER_OK;
    } else if (
	    (strcmpic(arg_defer_ok,US"1") == 0)
	|| (strcmpic(arg_defer_ok,US"yes") == 0)
	|| (strcmpic(arg_defer_ok,US"true") == 0)
	|| (strcmpic(arg_defer_ok,US"defer_ok") == 0)
	) {
	defer_ok = 1;
    } else {
	defer_ok = 0;
    }
debug_printf("  defer_ok: %d\n", defer_ok);

    if (argc < 3) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Bad number of arguments: %d", argc);
	*yield = string_sprintf("kas3 dlfunc: DEFER: Bad number of arguments: %d", argc);
	goto RETURN_DEFER;
    }

    if ((arg_socket_addr == NULL) || (arg_socket_addr[0] == 0)) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Spamtest access address not defined, cannot process mail by spam filtering");
	*yield = string_sprintf("kas3 dlfunc: DEFER: Spamtest access address not defined, cannot process mail by spam filtering");
	goto RETURN_DEFER;
    }

    if (arg_default_domain == NULL) arg_default_domain = (char *)&default_domain;

    bzero(&s,sizeof(s));
    s.access_address = arg_socket_addr;
    s.rw_timeout = KAS_DATA_TIMEOUT;
    s.connect_timeout = KAS_CONNECT_TIMEOUT;
    s.mail_domain = arg_default_domain;

debug_printf("Spam test session: %s %s %d %d\n", s.access_address, s.mail_domain, s.connect_timeout, s.rw_timeout);

    if ((errorcode = sts_init(&s)) < 0 ) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Unable to connect to %s (%s)", s.access_address, sts_strerror(errorcode));
	*yield = string_sprintf("kas3 dlfunc: DEFER: Unable to connect to %s (%s)", s.access_address, sts_strerror(errorcode));
	goto RETURN_DEFER;
    };

    spamtest_session_flag = 1;
    if ( ! s.should_store_message ) {
	/* SMTP mode, blackholing message because filter will send message */
	//recipients_count = 0;
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Filter in SMTP mode, Incorrect situation.");
	*yield = string_sprintf("kas3 dlfunc: DEFER: Filter in SMTP mode, Incorrect situation.");
	goto RETURN_DEFER;
    }

    sender_address = expand_string(US"${sender_address}");
    if (sender_address != NULL && sender_address[0] != '\0') {
debug_printf("Send sender address: %s\n", sender_address);
	if ((errorcode = sts_set_sender(&s, sender_address)) != STS_ERR_NO_ERR ) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"kas3 dlfunc: Unable to pass sender address %s (%d)", sender_address, errorcode);
	    *yield = string_sprintf("kas3 dlfunc: DEFER: Unable to pass sender address %s(%d)", sender_address, errorcode);
	    goto RETURN_DEFER;
	}
    }

    sender_host_address = expand_string(US"${sender_host_address}");
    if (sender_host_address != NULL && sender_host_address[0] != '\0') {
debug_printf("Send sender host address: %s\n", sender_host_address);
	if ((errorcode = sts_set_relay(&s, sender_host_address)) != STS_ERR_NO_ERR) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"kas3 dlfunc: Unable to pass relay IP %s (%d)", sender_host_address, errorcode);
	    if (errorcode == STS_ERR_OUT_OF_MEMORY) {
		*yield = string_sprintf("kas3 dlfunc: DEFER: Unable to pass relay IP %s (%d)", sender_host_address, errorcode);
	        goto RETURN_DEFER;
            }
	}
    }

    rcpt_sent = 0;
    for (i = 0; i < recipients_count; i++) {
	if (recipients_list[i].address != NULL && recipients_list[i].address[0] != '\0') {
debug_printf("Send recipient address: %s\n", recipients_list[i].address);
	    if ((errorcode = sts_add_recipient(&s,recipients_list[i].address)) != STS_ERR_NO_ERR) {
		log_write(0, LOG_MAIN|LOG_PANIC,
		    "kas3 dlfunc: Unable to pass recipient '%s' to filter",recipients_list[i].address);
	    } else {
		rcpt_sent++;
	    }
	}
    }
    if (rcpt_sent == 0) {
debug_printf("Recipients not sent to filter. Continue\n");
    }

#ifdef WITH_CONTENT_SCAN

debug_printf("Open spool file\n");

// make sure the eml mbox file is spooled up
    mbox_file = spool_mbox(&mbox_size);

    if (!mbox_file) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Unable to spool message");
	*yield = string_copy((uschar *)"kas3 dlfunc: Unable to spool message");
	goto RETURN_DEFER;
    }

    address = expand_string(US"${sender_address}");

    if (address && *address) {
	sprintf(buf, "Return-path: <%s>\n", address);
debug_printf("Send to socket: %s", buf);
	if ((status = sts_send_body(&s, buf, strlen(buf), STS_REINIT_TIMEOUT)) == NULL)
	    goto WRITE_FAILED;
    }

#else

    sprintf(mbox_path, "%s/input/%s-D", spool_directory, message_id);
debug_printf("Open spool file: %s\n", mbox_path);
    mbox_file = fopen(mbox_path,"rb");

    if (!mbox_file) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: Unable to spool message");
	*yield = string_copy((uschar *)"kas3 dlfunc: DEFER: Unable to spool message");
	goto RETURN_DEFER;
    }

debug_printf("fseek %d, %d\n", SPOOL_DATA_START_OFFSET, SEEK_SET);
    (void)fseek(mbox_file, SPOOL_DATA_START_OFFSET, SEEK_SET);

    address = expand_string(US"${sender_address}");

    if (address && *address) {
	sprintf(buf, "Return-path: <%s>\n", address);
debug_printf("Send to socket: %s", buf);
	if ((status = sts_send_body(&s, buf, strlen(buf), STS_REINIT_TIMEOUT)) == NULL)
	    goto WRITE_FAILED;
    }

//    address = expand_string(US"${if def:received_for{$received_for}}");
    address = expand_string(US"${received_for}");
    if (!address || !*address) address = expand_string(US"${recipients}");
    if (!address || !*address) address = expand_string(US"${local_part}@${domain}");

    if (address && *address) {
	sprintf(buf, "Envelope-To: %s\n", address);
debug_printf("Send to socket: %s", buf);
	if ((status = sts_send_body(&s, buf, strlen(buf), STS_REINIT_TIMEOUT)) == NULL)
	    goto WRITE_FAILED;
    }

    sprintf(buf, "Delivery-date: %s\n", tod_stamp(tod_full));
debug_printf("Send to socket: %s", buf);
    if ((status = sts_send_body(&s, buf, strlen(buf), STS_REINIT_TIMEOUT)) == NULL)
        goto WRITE_FAILED;

    my_headerlist = header_list;
    while (my_headerlist != NULL) {
	if (my_headerlist->type != '*') {
debug_printf("Send header. Iterating a, %c %d %s|%d\n", my_headerlist->type, my_headerlist->slen, my_headerlist->text, my_headerlist->text[my_headerlist->slen-1]);
	    if ((status = sts_send_body(&s, my_headerlist->text, my_headerlist->slen, STS_REINIT_TIMEOUT)) == NULL) {
		// failure. finish proceed
		log_write(0, LOG_MAIN|LOG_PANIC,
		    "kas3 dlfunc: NULL status after sending header %s", my_headerlist->text);
		*yield = string_sprintf("kas3 dlfunc: DEFER: NULL status after sending header %s", my_headerlist->text);
	        goto RETURN_DEFER;
	    } else {
		// check status and finish if need
debug_printf("Header '%s' sent to filter\n", my_headerlist->text);
		if (check_results(&s, status, &res, yield) > 0) {
		    if (res == LOCAL_SCAN_TEMPREJECT)
			goto RETURN_DEFER;
		    else if (res == LOCAL_SCAN_ACCEPT)
	    		goto RETURN_OK;
		    else if (res == LOCAL_SCAN_REJECT)
	    		goto RETURN_ERROR;
                }
	    }
	}
	if (my_headerlist == header_last) {
debug_printf("This was last header\n");
	    break;
	}
	my_headerlist = my_headerlist->next;
    }

debug_printf("Headers sent\n");

debug_printf("Send empty string\n");
    if ((status = sts_send_body(&s,"\n", 1, STS_REINIT_TIMEOUT)) == NULL) {
        // failure. finish proceed
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: NULL status after sending empty string (end of headers)");
	*yield = string_sprintf("kas3 dlfunc: DEFER: NULL status after sending empty string (end of headers)");
        goto RETURN_DEFER;
    } else {
	// check status and finish if need
debug_printf("Empty string (end of headers) sent to filter\n");
	if ( check_results(&s, status, &res, yield) > 0 ) {
	    if (res == LOCAL_SCAN_TEMPREJECT)
		goto RETURN_DEFER;
	    else if (res == LOCAL_SCAN_ACCEPT)
    		goto RETURN_OK;
	    else if (res == LOCAL_SCAN_REJECT)
    		goto RETURN_ERROR;
        }
    }

debug_printf("Enter sent\n");

#endif

    while ((cnt = fread(buf, 1, sizeof(buf) - 1, mbox_file)) > 0) {
	buf[cnt] = '\0';

#ifdef WITH_CONTENT_SCAN

	p = buf;
	if (mbox_delimiter_skiped == 0) {
debug_printf("Try to find unix mailbox delimiter\n");
    	    p = Ustrstr(buf, "From ");
	    if (p == buf) {
debug_printf("unix mailbox delimiter found\n");
    	        p = Ustrstr(buf, "\n");
	        if (p != NULL) {
		    p++;
		    cnt -= p - buf;
		}
	    }
	}
	mbox_delimiter_skiped = 1;
debug_printf("Send %d bytes to filter\n", cnt);
        status = sts_send_body(&s, p, cnt, STS_REINIT_TIMEOUT);
debug_printf("Sent to filter:\n%s", p);

#else

debug_printf("Send %d bytes to filter\n", cnt);
        status = sts_send_body(&s, buf, cnt, STS_REINIT_TIMEOUT);
debug_printf("Sent to filter:\n%s", buf);

#endif

	if (status == NULL) {
	    // failure. finish proceed 
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"kas3 dlfunc: NULL status after sending part of body");
	    *yield = string_copy((uschar *)"kas3 dlfunc: DEFER: NULL status after sending part of body");
	    goto RETURN_DEFER;
	} else { // check status and finish if need 
debug_printf("Part of body sent to filter\n");
	    if ( check_results(&s, status, &res, yield) > 0 ) {
		if (res == LOCAL_SCAN_TEMPREJECT)
		    goto RETURN_DEFER;
    		else if (res == LOCAL_SCAN_ACCEPT)
    		    goto RETURN_OK;
		else if (res == LOCAL_SCAN_REJECT)
    	    	    goto RETURN_ERROR;
    	    }
	}
	totalcnt += cnt;
    }

debug_printf("Total sent %d bytes of message\n",totalcnt);

    status = sts_body_end(&s, STS_FLUSH_DATA);
debug_printf("Body sent\n");

    if (check_results(&s, status, &res, yield) > 0 ){
	if (res == LOCAL_SCAN_TEMPREJECT)
	    goto RETURN_DEFER;
    	else if (res == LOCAL_SCAN_ACCEPT)
    	    goto RETURN_OK;
	else if (res == LOCAL_SCAN_REJECT)
    	    goto RETURN_ERROR;
    }

debug_printf("EOF\n");

    goto RETURN_OK;


WRITE_FAILED:
{
    // failure. finish proceed 
    log_write(0, LOG_MAIN|LOG_PANIC,
	"kas3 dlfunc: NULL status after sending part of body");
    *yield = string_copy((uschar *)"kas3 dlfunc: DEFER: NULL status after sending part of body");
    goto RETURN_DEFER;
}

RETURN_DEFER:
{
    if (mbox_file != NULL) (void)fclose(mbox_file);
    if (spamtest_session_flag) sts_close(&s);
    if ((*yield == NULL) || (*yield[0] == '\0'))
	*yield = string_sprintf("kas3 dlfunc: DEFER");
    return(defer_ok ? OK : ERROR);
}

RETURN_ERROR:
{
    if (mbox_file != NULL) (void)fclose(mbox_file);
    if (spamtest_session_flag) sts_close(&s);
    if ((*yield == NULL) || (*yield[0] == '\0'))
	*yield = string_sprintf("kas3 dlfunc: REJECT");
//    return(ERROR);
    return(OK);
}

RETURN_OK:
{
    if (mbox_file != NULL) (void)fclose(mbox_file);
    if (spamtest_session_flag) sts_close(&s);
    if ((*yield == NULL) || (*yield[0] == '\0'))
	*yield = string_sprintf("kas3 dlfunc: ACCEPT");
    return(OK);
}

    return OK;
}

//-------------------------------------------------------------------------

int check_results(spamtest_session_t *s, spamtest_status_t *status, int *res, uschar **return_text) {
debug_printf("Check results started\n");
    switch (status->status) {
    case STS_SMTP_ACCEPT:
    case STS_BLACKHOLE:
debug_printf("\tSMTP_ACCEPT or BLACK_HOLE\n");
        recipients_count = 0;
        sts_close(s);
	*res = LOCAL_SCAN_ACCEPT;
	return 1;
    case STS_REJECT:
debug_printf("\tREJECT\n");
	*return_text = string_sprintf("kas3 dlfunc: REJECT: %s", (uschar *)status->reason);
        *res = LOCAL_SCAN_REJECT;
	return 1;
    case STS_FILTER_ERROR:
debug_printf("\tFILTER_ERROR\n");
	*return_text = string_copy((uschar *)"kas3 dlfunc: DEFER: filter error");
        *res =  LOCAL_SCAN_TEMPREJECT;
	return 1;
    case STS_SENDERROR:
debug_printf("\tSENDERROR\n");
	*return_text = string_copy((uschar *)"kas3 dlfunc: DEFER: I/O or other error");
        *res =  LOCAL_SCAN_TEMPREJECT;
	return 1;
    case STS_ACCEPT:
debug_printf("\tACCEPT\n");
	if (proceed_accept(status, return_text) != 0)
    	    *res = LOCAL_SCAN_TEMPREJECT;
	else
    	    *res = LOCAL_SCAN_ACCEPT;
    	sts_close(s);
	return 1;
    case STS_CONTINUE:
debug_printf("\tCONTINUE\n");
	return 0;
    default:
debug_printf("\tUnknown status: %d\n", status->status);
	return 0;
    }

}

//-------------------------------------------------------------------------

extern int recipients_list_max;
int proceed_accept(spamtest_status_t *status, uschar **return_text) {
    spamtest_status_t *st;
    message_status_t *mst;
    int		i;
    int		rcptn;
    int		good_rcpt_cnt = 0,k;
    int		found = 0;
    char	buf[40960];

debug_printf("Accept_message started\n");

    st = glue_actions(status);

    if (st==NULL) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: glue_actions return NULL");
	*return_text = string_copy((uschar *)"kas3 dlfunc: DEFER: glue_actions return NULL");
	return -1;
    }

    mst = &st->ms_array[0] ;

    rcptn = rcptlist_count(mst->rcpts);
    for (k = 0; k < rcptn; k++)
	if (strlen(rcptlist_getn(mst->rcpts, k)) > 0)
	    good_rcpt_cnt++;
    if (good_rcpt_cnt <1) {
debug_printf("Empty recipient list\n");
	log_write(0, LOG_MAIN,
	    "kas3 dlfunc: Empty recipient list");
	recipients_count = 0;
	return 0;
    }

    if ((mst != NULL) && (mst->action == STS_ACTION_CHANGE)) {
debug_printf("spamtest status returned STS_ACTION_CHANGE for message\n");

    bzero(&buf,sizeof(buf));

debug_printf("Actions count = %d\n", mst->action_count);
	for (i = 0; i < mst->action_count; i++) {
	    int hdrlen;

debug_printf("action type: %d\n", mst->act_array[i].type);
	    
	    hdrlen = (mst->act_array[i].header == NULL ? 0 : strlen(mst->act_array[i].header));
	    if (mst->act_array[i].value != NULL) hdrlen += strlen(mst->act_array[i].value) + 3;

	    switch (mst->act_array[i].type) {
		case STS_HEADER_DEL:
debug_printf("Delete header %s\n", mst->act_array[i].header);


		    break;
		case STS_HEADER_ADD:
debug_printf("Add value to header %s %s\n", mst->act_array[i].header,mst->act_array[i].value);
		    if (hdrlen < sizeof(buf) - Ustrlen(buf)) {
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].header);
		        Ustrcpy(buf + Ustrlen(buf), ": ");
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].value);
			Ustrcpy(buf + Ustrlen(buf), "\n");
		    }


		    break;
		case STS_HEADER_PREPEND:
debug_printf("Prepend value to header %s %s\n", mst->act_array[i].header, mst->act_array[i].value);
		    if (hdrlen < sizeof(buf) - Ustrlen(buf)) {
			Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].header);
		        Ustrcpy(buf + Ustrlen(buf), ": ");
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].value);
		        Ustrcpy(buf + Ustrlen(buf), "\n");
		    }


		    break;
		case STS_HEADER_CHG:
debug_printf("Change header %s %s\n", mst->act_array[i].header,mst->act_array[i].value);
		    if (hdrlen < sizeof(buf) - Ustrlen(buf)) {
			Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].header);
		        Ustrcpy(buf + Ustrlen(buf), ": ");
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].value);
		        Ustrcpy(buf + Ustrlen(buf), "\n");
		    }


		    break;
		case STS_HEADER_NEW:
debug_printf("New header %s: %s\n", mst->act_array[i].header, mst->act_array[i].value);
		    if (hdrlen < sizeof(buf) - Ustrlen(buf)) {
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].header);
		        Ustrcpy(buf + Ustrlen(buf), ": ");
		        Ustrcpy(buf + Ustrlen(buf), mst->act_array[i].value);
		        Ustrcpy(buf + Ustrlen(buf), "\n");
		    }
		    break;
		default:
		    log_write(0, LOG_MAIN,
			"kas3 dlfunc: Invalid action type %d",mst->act_array[i].type);
	    }
debug_printf("buf: '%s'\n", buf);
	}
	*return_text = string_sprintf((uschar *)"kas3 dlfunc: ACCEPT: %s", buf);
    } else if ((mst != NULL) && (mst->action == STS_ACTION_BOUNCE)) {
	// bounce message
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "kas3 dlfunc: spamtest status returned STS_ACTION_BOUNCE for message, but we don't support this status");
	*return_text = string_copy((uschar *)"kas3 dlfunc: DEFER: spamtest status returned STS_ACTION_BOUNCE for message, but we don't support this status");
	return -1;
    } else {
	if ( mst != NULL ) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"kas3 dlfunc: Invalid action %d", mst->action);
	    *return_text = string_sprintf("kas3 dlfunc: DEFER: Invalid action %d", mst->action);
	} else {
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"kas3 dlfunc: mst is NULL");
	    *return_text = string_sprintf("kas3 dlfunc: DEFER: mst is NULL");
	}
	return -1;
    }

debug_printf("Message accepted\n");
    return 0;
}