/*
   3APA3A simplest proxy server
   (c) 2002-2026 by Vladimir Dubrovin <vlad@3proxy.org>

   please read License Agreement

*/

#include "proxy.h"

#ifdef WITH_SMTPP

#define RETURN(xxx) { param->res = xxx; goto CLEANRET; }

#ifdef WITHMAIN
#define NOSTARTTLS 1
#else
#define NOSTARTTLS param->srv->nostarttls
#endif

char  ehlo[] = 	"250-Proxy\r\n"
		"250-AUTH PLAIN LOGIN\r\n"
		"250-8BITMIME\r\n"
		"250 DSN\r\n";

char  ehlotls[] = 	"250-Proxy\r\n"
		"250-AUTH PLAIN LOGIN\r\n"
		"250-8BITMIME\r\n"
		"250-STARTTLS\r\n"
		"250 DSN\r\n";

int readreply (struct clientparam* param) {
 unsigned char * buf;
 int res, i, bufsize = 640;

 buf = param->tmpbuf;	/* a filter may replace it with one of its own */
 do {
	i = sockgetlinebuf(param, SERVER, buf, bufsize-1, '\n', conf.timeouts[STRING_L]);
	if(i < 1) break;
#ifndef WITHMAIN
	res = handlehdrfilterssrv(param, &buf, &bufsize, 0, &i);
	if(res != PASS) {
		if(buf != param->tmpbuf) free(buf);
		return -1;
	}
#endif
	socksend(param, param->clisock, buf, i, conf.timeouts[STRING_S]);	
 } while (i > 3 && buf[3] == '-');
 if(i < 3) {
	if(buf != param->tmpbuf) free(buf);
	return 0;
 }
 buf[i] = 0;
 res = atoi((char *)buf);
 if(buf != param->tmpbuf) free(buf);
 return res;
}

int readcommand (struct clientparam* param) {
 unsigned char * buf;
 int i, bufsize = 320;
#ifndef WITHMAIN
 int res;
#endif
 int ret = 1;

 buf = param->tmpbuf;	/* a filter may replace it with one of its own */
 i = sockgetlinebuf(param, CLIENT, buf, bufsize-1, '\n', conf.timeouts[STRING_L]);
 if(i < 4) return 0;
#ifndef WITHMAIN
 if(!strncasecmp((char *)buf, "MAIL", 4) || !strncasecmp((char *)buf, "RCPT", 4) || !strncasecmp((char *)buf, "STARTTLS", 8) || !strncasecmp((char *)buf, "TURN", 4)){
	res = handlehdrfilterscli(param, &buf, &bufsize, 0, &i);
	if(res != PASS) {
		if(buf != param->tmpbuf) free(buf);
		if(res == HANDLED) return 2;
		return -1;
	}
 }
#endif
 socksend(param, param->remsock, buf, i, conf.timeouts[STRING_S]);	
 if(!strncasecmp((char *)buf, "STARTTLS", 8) || !strncasecmp((char *)buf, "TURN", 4)){
	ret = 22;
 }
 if(buf != param->tmpbuf) free(buf);
 return ret;
}

int readdata (struct clientparam* param) {
 unsigned char * buf;
 int i, bufsize = 4096;
#ifndef WITHMAIN
 int res;
#endif

 buf = param->tmpbuf;	/* a filter may replace it with one of its own */
 while ((i = sockgetlinebuf(param, CLIENT, buf, bufsize-1, '\n', conf.timeouts[STRING_L])) > 0 && !(i==3 && buf[0] == '.')){
#ifndef WITHMAIN
	res = handledatfltcli(param, &buf, &bufsize, 0, &i);
	if(res != PASS) {
		if(buf != param->tmpbuf) free(buf);
		if(res == HANDLED) return 1;
		return -1;
	}
#endif
	socksend(param, param->remsock, buf, i, conf.timeouts[STRING_S]);	
 } 
 if(i < 1) {
	if(buf != param->tmpbuf) free(buf);
	return 0;
 }
 socksend(param, param->remsock, buf, i, conf.timeouts[STRING_S]);	
 if(buf != param->tmpbuf) free(buf);
 return 1;
}


void * smtppchild(struct clientparam* param) {
 int i=0, res;
 unsigned char buf[320];
 unsigned char username[256];
 char * command = NULL;
 int login = 0;

 if(socksend(param, param->clisock, (unsigned char *)"220 Proxy\r\n", 11, conf.timeouts[STRING_S])!=11) {RETURN (611);}
 i = sockgetlinebuf(param, CLIENT, buf, sizeof(buf) - 10, '\n', conf.timeouts[STRING_S]);
 while(i > 4 && (strncasecmp((char *)buf, "AUTH PLAIN", 10) || !(login = 2)) && (strncasecmp((char *)buf, "AUTH LOGIN", 10) || !(login = 1))){
	if(!strncasecmp((char *)buf, "QUIT", 4)){
		socksend(param, param->clisock, (unsigned char *)"221 Proxy\r\n", 11,conf.timeouts[STRING_S]);	
		RETURN(0);
	}
	else if(!strncasecmp((char *)buf, "HELO ", 5)){
		socksend(param, param->clisock, (unsigned char *)"250 Proxy\r\n", 11,conf.timeouts[STRING_S]);	
	}
	else if(!strncasecmp((char *)buf, "EHLO ", 5)){
		if(!NOSTARTTLS) socksend(param, param->clisock, (unsigned char *)ehlotls, sizeof(ehlotls) - 1,conf.timeouts[STRING_S]);
		else socksend(param, param->clisock, (unsigned char *)ehlo, sizeof(ehlo) - 1,conf.timeouts[STRING_S]);
	}
#ifndef WITHMAIN
	else if(!strncasecmp((char *)buf, "STARTTLS", 8) && !param->srv->nostarttls){
		if(socksend(param, param->clisock, (unsigned char *)"220 2.0.0 Ready to start TLS\r\n", 30, conf.timeouts[STRING_S])!=30) {RETURN(673);}
		param->clientstarttls = S_SMTPP;
		if(!param->srv->targetport) param->srv->targetport = htons(587);
		return (void *)tlsprchild;
	}
#endif
	else if(!*param->hostname) socksend(param, param->clisock, (unsigned char *)"571 need AUTH first\r\n", 22, conf.timeouts[STRING_S]);
	else {
		login = -1;
		buf[i] = 0;
		command = strdup((char *)buf);
		break;
	}
	i = sockgetlinebuf(param, CLIENT, buf, sizeof(buf) - 10, '\n', conf.timeouts[STRING_S]);
 }
 if(!login) {RETURN(662);}
 if(login == 1){
	socksend(param, param->clisock, (unsigned char *)"334 VXNlcm5hbWU6\r\n", 18,conf.timeouts[STRING_S]);	
	i = sockgetlinebuf(param, CLIENT, buf, sizeof(buf) - 10, '\n', conf.timeouts[STRING_S]);
	if(i < 3) {RETURN(663);}
	buf[i-2] = 0;
	i = de64(buf,username,255);
	if(i < 1) {RETURN(664);}
	username[i] = 0;
	/* The name has to carry the host to connect to, and the answer says
	   whether it did: without one there is nowhere to go, and what follows
	   reads the name as if there were. */
	if(parseconnusername((char *)username, param, 0, 587)) {RETURN(669);}
	socksend(param, param->clisock, (unsigned char *)"334 UGFzc3dvcmQ6\r\n", 18,conf.timeouts[STRING_S]);	
	i = sockgetlinebuf(param, CLIENT, buf, sizeof(buf) - 10, '\n', conf.timeouts[STRING_S]);
	if(i < 2) {RETURN(665);}
	buf[i-2] = 0;
	i = de64(buf,username,255);
	if(i < 0) {RETURN(666);}
	username[i] = 0;
	if(PARAMSTR(param, extpassword, username)) {RETURN(666);}
 }
 else if(login == 2){
	if(i > 13) {
		buf[i-2] = 0;
		i = de64(buf+11,username,255);
	}
	else {
		socksend(param, param->clisock, (unsigned char *)"334\r\n", 5,conf.timeouts[STRING_S]);	
		i = sockgetlinebuf(param, CLIENT, buf, sizeof(buf) - 10, '\n', conf.timeouts[STRING_S]);
		if(i < 3) {RETURN(667);}
		buf[i-2] = 0;
		i = de64(buf,username,255);
	}
	if(i < 3 || *username) {RETURN(668);}
	username[i] = 0;
	if(parseconnusername((char *)username+1, param, 0, 587)) {RETURN(670);}
	res = (int)strlen((char *)username+1) + 2;
	if(res < i){
		if(PARAMSTR(param, extpassword, username + res)) {RETURN(670);}
	}
 }

#ifndef WITHMAIN
 {
	/* the host is filtered as a request, in the scratch buffer, where a
	   filter may also hand back a buffer of its own */
	int action, reqbufsize, reqsize;
	unsigned char *req = param->tmpbuf;

	reqsize = (int)strlen((char *)param->hostname) + 1;
	reqbufsize = CLIENTTMPBUFSIZE;
	memcpy(req, param->hostname, reqsize);
	action = handlereqfilters(param, &req, &reqbufsize, 0, &reqsize);
	if(action == PASS && PARAMSTR(param, hostname, req)) action = REJECT;
	if(req != param->tmpbuf) free(req);
	if(action == HANDLED){
		RETURN(0);
	}
	if(action != PASS) RETURN(617);
 }
#endif

 param->operation = CONNECT;
 res = (*param->srv->authfunc)(param);
 if(res) {RETURN(res);}
 i = getmultiline(param, SERVER, buf, sizeof(buf) - 1, NULL, NULL);
 if( i < 3 ) {RETURN(671);}
 buf[i] = 0;
 if(strncasecmp((char *)buf, "220", 3)||!strncasecmp((char *)buf+4, "PROXY", 5)){RETURN(672);}
 i = sprintf((char *)buf, "EHLO [");
 i += myinet_ntop(*SAFAMILY(&param->sinsl), SAADDR(&param->sinsl), (char *)buf+strlen((char *)buf), 64);
 i += sprintf((char *)buf+strlen((char *)buf), "]\r\n");
 if(socksend(param, param->remsock, buf, i, conf.timeouts[STRING_S])!= i) {RETURN(673);}
 param->statscli64+=i;
 param->nwrites++;
 login = 0;
 do {
	i = sockgetlinebuf(param, SERVER, buf, sizeof(buf) - 1, '\n', conf.timeouts[STRING_L]);
	if(i < 1) break;
	buf[i] = 0;
	if(strstr((char *)buf, "LOGIN")) login |= 1;
	if(strstr((char *)buf, "PLAIN")) login |= 2;

 } while (i > 3 && buf[3] == '-');
 if(i<3) {RETURN(672);}
 if(!command || (*param->extusername && *param->extpassword)){
	if(!*param->extusername || !*param->extpassword || !login){
		socksend(param, param->clisock, (unsigned char *)"235 auth required\r\n", 19,conf.timeouts[STRING_S]);	
	}
	if ((login & 1)) {
		socksend(param, param->remsock, (unsigned char *)"AUTH LOGIN\r\n", 12, conf.timeouts[STRING_S]);
 param->statscli64+=12;
		param->nwrites++;
		i = sockgetlinebuf(param, SERVER, buf, sizeof(buf) - 1, '\n', conf.timeouts[STRING_L]);
		if(i<4 || strncasecmp((char *)buf, "334", 3)) {RETURN(680);}
		if(!en64(param->extusername, buf, (int)strlen((char *)param->extusername), (int)sizeof(buf))) {RETURN(683);}
		socksend(param, param->remsock, buf, (int)strlen((char *)buf), conf.timeouts[STRING_S]);
		socksend(param, param->remsock, (unsigned char *)"\r\n", 2, conf.timeouts[STRING_S]);
 param->statscli64+=(i+2);
		param->nwrites+=2;
		i = sockgetlinebuf(param, SERVER, buf, sizeof(buf) - 1, '\n', conf.timeouts[STRING_L]);
		if(i<4 || strncasecmp((char *)buf, "334", 3)) {RETURN(681);}
		if(!en64(param->extpassword, buf, (int)strlen((char *)param->extpassword), (int)sizeof(buf))) {RETURN(683);}
		socksend(param, param->remsock, buf, (int)strlen((char *)buf), conf.timeouts[STRING_S]);
		socksend(param, param->remsock, (unsigned char *)"\r\n", 2, conf.timeouts[STRING_S]);
 param->statscli64+=(i+2);
		param->nwrites+=2;
	}
	else if((login & 2)){
		socksend(param, param->remsock, (unsigned char *)"AUTH PLAIN\r\n", 12, conf.timeouts[STRING_S]);
 param->statscli64+=(12);
		param->nwrites++;
		i = sockgetlinebuf(param, SERVER, buf, sizeof(buf) - 1, '\n', conf.timeouts[STRING_L]);
		if(i<4 || strncasecmp((char *)buf, "334", 3)) {RETURN(682);}
		*username = 0;
		i = (int)strlen((char *)param->extusername) + 1;
		res = (int)strlen((char *)param->extpassword);
		if(i + 1 + res >= (int)sizeof(username)) {RETURN(683);}
		memcpy(username+1, param->extusername,  i);
		i++;
		memcpy(username + i, param->extpassword, res);
		i+=res;
		if(!en64(username, buf, i, (int)sizeof(buf))) {RETURN(683);}
		i = (int)strlen((char *)buf);
		socksend(param, param->remsock, buf, i, conf.timeouts[STRING_S]);
		socksend(param, param->remsock, (unsigned char *)"\r\n", 2, conf.timeouts[STRING_S]);
 param->statscli64+=(i+2);
		param->nwrites+=2;
	}
	if(command) {
		i = sockgetlinebuf(param, SERVER, buf, sizeof(buf) - 1, '\n', conf.timeouts[STRING_L]);
	}
	res = 1;
 }
 if(command) {
	res = 1;
#ifndef WITHMAIN
	if(!strncasecmp(command, "MAIL", 4) || !strncasecmp(command, "RCPT", 4) || !strncasecmp(command, "STARTTLS", 8) || !strncasecmp(command, "TURN", 4)){
		int clen = (int)strlen(command), csize = clen + 1;

		res = handlehdrfilterscli(param, (unsigned char **)&command, &csize, 0, &clen);
		if(res != PASS) {
			if(res == HANDLED) res = 2;
			else RETURN(677);
		}
		else if(!strncasecmp(command, "STARTTLS", 8) || !strncasecmp(command, "TURN", 4))
			res = 22;
	}
#endif
	i = (int)strlen(command);
	if(res != 2) socksend(param, param->remsock, (unsigned char *)command, i, conf.timeouts[STRING_S]);
 }
#ifndef WITHMAIN

 if(param->nhdrfilterscli || param->nhdrfilterssrv || param->ndatfilterscli || param->ndatfilterssrv){
	do {
		if(res == 22) RETURN (mapsocket(param, 180));
		if(res != 2 && (res = readreply(param)) <= 0) break;
		if(res == 221) RETURN(0);
		if(res == 354) res = readdata(param);
		else res = readcommand(param);
	} while(res > 0);
	if(res == 22) 
	if(res >= 0) RETURN(0);
	RETURN(676);
 }
 else

#endif
 
 	RETURN (mapsocket(param, 180));

CLEANRET:

 if(*param->hostname&&*param->extusername) {
	sprintf((char *)buf, "%.128s@%.128s%c%hu", param->extusername, param->hostname, *SAPORT(&param->sinsr)==587?0:':',ntohs(*SAPORT(&param->sinsr)));
	 dolog(param, buf);
 }
 else dolog(param, NULL);
 if(param->clisock != INVALID_SOCKET) {
	if ((param->res > 0 && param->res < 100) || (param->res > 661 && param->res <700)) socksend(param, param->clisock, (unsigned char *)"571 \r\n", 6,conf.timeouts[STRING_S]);
 }
 if(command) free(command);
 return (NULL);
}

#ifdef WITHMAIN
struct proxydef childdef = {
	smtppchild,
	587,
	0,
	S_SMTPP,
	" -hdefault_host[:port] - use this host and port as default if no host specified\n -x - disable STARTTLS\n"

};
#include "proxymain.c"
#endif
#else

/* Built without this proxy of its own. The command and the redirect
   naming it are the STARTTLS proxy speaking that protocol, which
   negotiates the same way and passes the session on: what "tlspr -Xsmtp"
   does, under the name a configuration already uses. */
void * smtppchild(struct clientparam * param){
	param->starttls = S_SMTPP;
	return (void *)tlsprchild;
}

#endif