/*
 
 imap4 banner checker
 
 
 */

#include "proto-imap4.h"
#include "proto-banner1.h"
#include "unusedparm.h"
#include "masscan-app.h"
#include "stack-tcp-api.h"
#include "proto-ssl.h"
#include <ctype.h>
#include <string.h>


/***************************************************************************
 ***************************************************************************/
static void
imap4_parse(  const struct Banner1 *banner1,
           void *banner1_private,
           struct StreamState *pstate,
           const unsigned char *px, size_t length,
           struct BannerOutput *banout,
           struct stack_handle_t *socket)
{
    unsigned state = pstate->state;
    unsigned i;
    
    UNUSEDPARM(banner1_private);
    UNUSEDPARM(banner1);
    
    
    for (i=0; i<length; i++) {
        if (px[i] == '\r')
            continue;
        
        switch (state) {
            case 0:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '*')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 1:
                if (px[i] == ' ') {
                    banout_append_char(banout, PROTO_IMAP4, px[i]);
                    continue;
                } else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                /* fall through */
            case 2:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == 'O')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 3:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == 'K')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 4:
                if (px[i] == ' ') {
                    banout_append_char(banout, PROTO_IMAP4, px[i]);
                    state++;
                    break;
                } else if (px[i] != '\n') {
                    banout_append_char(banout, PROTO_IMAP4, px[i]);
                    /* no transition */
                    break;
                } else {
                    state++;
                    /* fall through */
                }
            case 5:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '\n') {
                    tcpapi_send(socket, "a001 CAPABILITY\r\n", 17, 0);
                    state = 100;
                }
                break;
            case 100:
            case 300:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '*')
                    state += 100;
                else if (px[i] == 'a')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 101:
            case 301:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '0')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 102:
            case 302:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '0')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 103:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '1')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 303:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '2')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 104:
            case 304:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == ' ')
                    state++;
                else {
                    state = 0xffffffff;
                    tcpapi_close(socket);
                }
                break;
            case 105:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '\n') {
                    tcpapi_send(socket, "a002 STARTTLS\r\n", 15, 0);
                    state = 300;
                }
                break;
                
            case 200:
            case 400:
                banout_append_char(banout, PROTO_IMAP4, px[i]);
                if (px[i] == '\n')
                    state -= 100;
                break;
                
            case 305:
                if (px[i] == '\n') {
                    /* change the state here to SSL */
                    unsigned port = pstate->port;
                    memset(pstate, 0, sizeof(*pstate));
                    pstate->app_proto = PROTO_SSL3;
                    pstate->is_sent_sslhello = 1;
                    pstate->port = (unsigned short)port;
                    state = 0;
                    
                    tcpapi_send(socket, banner_ssl.hello, banner_ssl.hello_length, 0);
                    break;
                }
                break;
                
            case 0xffffffff:
            default:
                i = (unsigned)length;
                break;
        }
    }
    pstate->state = state;
}

/***************************************************************************
 ***************************************************************************/
static void *
imap4_init(struct Banner1 *banner1)
{
    UNUSEDPARM(banner1);
    return 0;
}


/***************************************************************************
 ***************************************************************************/
static int
imap4_selftest(void)
{
    return 0;
}

/***************************************************************************
 ***************************************************************************/
const struct ProtocolParserStream banner_imap4 = {
    "imap4", 21, 0, 0, 0,
    imap4_selftest,
    imap4_init,
    imap4_parse,
};