mailsrvr.c

/* Synchronet Mail (SMTP/POP3) server and sendmail threads */

/****************************************************************************
 * @format.tab-size 4		(Plain Text/Source Code File Header)			*
 * @format.use-tabs true	(see http://www.synchro.net/ptsc_hdr.html)		*
 *																			*
 * Copyright Rob Swindell - http://www.synchro.net/copyright.html			*
 *																			*
 * This program is free software; you can redistribute it and/or			*
 * modify it under the terms of the GNU General Public License				*
 * as published by the Free Software Foundation; either version 2			*
 * of the License, or (at your option) any later version.					*
 * See the GNU General Public License for more details: gpl.txt or			*
 * http://www.fsf.org/copyleft/gpl.html										*
 *																			*
 * For Synchronet coding style and modification guidelines, see				*
 * http://www.synchro.net/source.html										*
 *																			*
 * Note: If this box doesn't appear square, then you need to fix your tabs.	*
 ****************************************************************************/

/* ANSI C Library headers */
#include <limits.h>			/* UINT_MAX */
#include <stdio.h>
#include <stdlib.h>			/* ltoa in GNU C lib */
#include <stdarg.h>			/* va_list */
#include <string.h>			/* strrchr */
#include <fcntl.h>			/* Open flags */
#include <errno.h>			/* errno */

/* Synchronet-specific headers */
#undef SBBS	/* this shouldn't be defined unless building sbbs.dll/libsbbs.so */
#include "sbbs.h"
#include "mailsrvr.h"
#include "utf8.h"
#include "mime.h"
#include "md5.h"
#include "crc32.h"
#include "base64.h"
#include "ini_file.h"
#include "netwrap.h"	/* getNameServerList() */
#include "xpendian.h"
#include "js_rtpool.h"
#include "js_request.h"
#include "multisock.h"
#include "ssl.h"
#include "cryptlib.h"
#include "ver.h"

/* Constants */
static const char*	server_name="Synchronet Mail Server";
#define FORWARD			"forward:"
#define NO_FORWARD		"local:"
#define NO_SPAM			"#nospam"

int dns_getmx(char* name, char* mx, char* mx2
			  ,DWORD intf, DWORD ip_addr, BOOL use_tcp, int timeout);

#define pop_error		"-ERR System Error: %s, try again later"
#define pop_auth_error	"-ERR Authentication failure"
#define ok_rsp			"250 OK"
#define auth_ok			"235 User Authenticated"
#define smtp_error		"421 System Error: %s, try again later"
#define insuf_stor		"452 Insufficient system storage"
#define badarg_rsp 		"501 Bad argument"
#define badseq_rsp		"503 Bad sequence of commands"
#define badauth_rsp		"535 Authentication failure"
#define badrsp_err		"%s replied with:\r\n\"%s\"\r\ninstead of the expected reply:\r\n\"%s ...\""

#define TIMEOUT_THREAD_WAIT		60		/* Seconds */
#define DNSBL_THROTTLE_VALUE	1000	/* Milliseconds */
#define SMTP_MAX_BAD_CMDS		9

#define STATUS_WFC	"Listening"

static mail_startup_t* startup=NULL;
static scfg_t	scfg;
static char*	text[TOTAL_TEXT];
static struct xpms_set	*mail_set=NULL;
static BOOL terminated=FALSE;
static protected_uint32_t active_clients;
static protected_uint32_t thread_count;
static volatile int		active_sendmail=0;
static volatile BOOL	sendmail_running=FALSE;
static volatile BOOL	terminate_server=FALSE;
static volatile BOOL	terminate_sendmail=FALSE;
static sem_t	sendmail_wakeup_sem;
static volatile time_t	uptime;
static str_list_t recycle_semfiles;
static str_list_t shutdown_semfiles;
static int		mailproc_count;
static js_server_props_t js_server_props;
static link_list_t current_logins;
static link_list_t current_connections;
static bool savemsg_mutex_created = false;
static pthread_mutex_t savemsg_mutex;

static const char* servprot_smtp = "SMTP";
static const char* servprot_submission = "SMTP";
static const char* servprot_submissions = "SMTPS";
static const char* servprot_pop3 = "POP3";
static const char* servprot_pop3s = "POP3S";

struct {
	volatile ulong	sockets;
	volatile ulong	errors;
	volatile ulong	crit_errors;
	volatile ulong	connections_exceeded;
	volatile ulong	connections_ignored;
	volatile ulong	connections_refused;
	volatile ulong	connections_served;
	volatile ulong	pop3_served;
	volatile ulong	smtp_served;
	/* SMTP: */
	volatile ulong	sessions_refused;
	volatile ulong	msgs_ignored;
	volatile ulong	msgs_refused;
	volatile ulong	msgs_received;
} stats;

struct mailproc {
	char		name[INI_MAX_VALUE_LEN];
	char		cmdline[INI_MAX_VALUE_LEN];
	char		eval[INI_MAX_VALUE_LEN];
	str_list_t	to;
	str_list_t	from;
	BOOL		passthru;
	BOOL		native;
	BOOL		ignore_on_error;	/* Ignore mail message if cmdline fails */
	BOOL		disabled;
	BOOL		process_spam;
	BOOL		process_dnsbl;
	uint8_t*	ar;
	ulong		handled;			/* counter (for stats display) */
} *mailproc_list;

typedef struct {
	SOCKET			socket;
	union xp_sockaddr	client_addr;
	socklen_t		client_addr_len;
	BOOL			tls_port;
} smtp_t,pop3_t;

#define GCES(status, server, sock, sess, action) do {                             \
	char *GCES_estr;                                                               \
	int GCES_level;                                                                 \
	get_crypt_error_string(status, sess, &GCES_estr, action, &GCES_level);  \
	if (GCES_estr) {                                                                  \
		lprintf(GCES_level, "%04d %s %s", sock, server, GCES_estr);                     \
		free_crypt_attrstr(GCES_estr);                                                  \
	}                                                                                    \
} while(0)

#define GCESH(status, server, sock, host, sess, action) do {                      \
	char *GCES_estr;                                                               \
	int GCES_level;                                                                 \
	get_crypt_error_string(status, sess, &GCES_estr, action, &GCES_level);  \
	if (GCES_estr) {                                                                  \
		lprintf(GCES_level, "%04d %s [%s] %s", sock, server, host, GCES_estr);         \
		free_crypt_attrstr(GCES_estr);                                                  \
	}                                                                                    \
} while(0)

#define GCESHL(status, server, sock, host, log_level, sess, action) do {                      \
	char *GCES_estr;                                                               \
	int GCES_level;                                                                 \
	get_crypt_error_string(status, sess, &GCES_estr, action, &GCES_level);  \
	if (GCES_estr) {                                                                  \
		lprintf(log_level, "%04d %s [%s] %s", sock, server, host, GCES_estr);         \
		free_crypt_attrstr(GCES_estr);                                                  \
	}                                                                                    \
} while(0)

#if defined(__GNUC__)   // Catch printf-format errors with lprintf
static int lprintf(int level, const char *fmt, ...) __attribute__ ((format (printf, 2, 3)));
#endif
static int lprintf(int level, const char *fmt, ...)
{
	va_list argptr;
	char sbuf[1024];

	va_start(argptr,fmt);
    vsnprintf(sbuf,sizeof(sbuf),fmt,argptr);
	sbuf[sizeof(sbuf)-1]=0;
    va_end(argptr);

	if(level <= LOG_ERR) {
		char errmsg[sizeof(sbuf)+16];
		SAFEPRINTF(errmsg, "mail %s", sbuf);
		errorlog(&scfg, level, startup==NULL ? NULL:startup->host_name,errmsg), stats.errors++;
		if(startup!=NULL && startup->errormsg!=NULL)
			startup->errormsg(startup->cbdata,level,errmsg);
	}

	if(level <= LOG_CRIT)
		stats.crit_errors++;

    if(startup==NULL || startup->lputs==NULL || level > startup->log_level)
		return(0);

#if defined(_WIN32)
	if(IsBadCodePtr((FARPROC)startup->lputs))
		return(0);
#endif

    return(startup->lputs(startup->cbdata, level, condense_whitespace(sbuf)));
}

#ifdef _WINSOCKAPI_

static WSADATA WSAData;
#define SOCKLIB_DESC WSAData.szDescription
static BOOL WSAInitialized=FALSE;

static BOOL winsock_startup(void)
{
	int		status;             /* Status Code */

    if((status = WSAStartup(MAKEWORD(1,1), &WSAData))==0) {
		lprintf(LOG_DEBUG,"%s %s",WSAData.szDescription, WSAData.szSystemStatus);
		WSAInitialized=TRUE;
		return (TRUE);
	}

    lprintf(LOG_CRIT,"!WinSock startup ERROR %d", status);
	return (FALSE);
}

#else /* No WINSOCK */

#define winsock_startup()	(TRUE)
#define SOCKLIB_DESC NULL

#endif

static char* server_host_name(void)
{
	return startup->host_name[0] ? startup->host_name : scfg.sys_inetaddr;
}

static void update_clients(void)
{
	if(startup!=NULL && startup->clients!=NULL)
		startup->clients(startup->cbdata,protected_uint32_value(active_clients)+active_sendmail);
}

static void client_on(SOCKET sock, client_t* client, BOOL update)
{
	if(!update)
		listAddNodeData(&current_connections, client->addr, strlen(client->addr)+1, sock, LAST_NODE);
	if(startup!=NULL && startup->client_on!=NULL)
		startup->client_on(startup->cbdata,TRUE,sock,client,update);
}

static void client_off(SOCKET sock)
{
	listRemoveTaggedNode(&current_connections, sock, /* free_data */TRUE);
	if(startup!=NULL && startup->client_on!=NULL)
		startup->client_on(startup->cbdata,FALSE,sock,NULL,FALSE);
}

static void thread_up(BOOL setuid)
{
	if(startup!=NULL && startup->thread_up!=NULL)
		startup->thread_up(startup->cbdata,TRUE,setuid);
}

static int32_t thread_down(void)
{
	int32_t count = protected_uint32_adjust_fetch(&thread_count,-1);
	if(startup!=NULL && startup->thread_up!=NULL)
		startup->thread_up(startup->cbdata,FALSE,FALSE);
	return count;
}

void mail_open_socket(SOCKET sock, void* cb_protocol)
{
	char	*protocol=(char *)cb_protocol;
	char	error[256];
	char	section[128];

	if(startup!=NULL && startup->socket_open!=NULL)
		startup->socket_open(startup->cbdata,TRUE);
	SAFEPRINTF(section,"mail|%s",protocol);
	if(set_socket_options(&scfg, sock, section, error, sizeof(error)))
		lprintf(LOG_ERR,"%04d %s !ERROR %s", sock, protocol, error);

	stats.sockets++;
}

void mail_close_socket_cb(SOCKET sock, void* cb_protocol)
{
	if(startup!=NULL && startup->socket_open!=NULL)
		startup->socket_open(startup->cbdata,FALSE);
	stats.sockets--;
}

int mail_close_socket(SOCKET *sock, int *sess)
{
	int		result;

	if (*sess != -1) {
		cryptDestroySession(*sess);
		*sess = -1;
	}
	if(*sock==INVALID_SOCKET)
		return(-1);

	shutdown(*sock,SHUT_RDWR);	/* required on Unix */
	result=closesocket(*sock);
	if(startup!=NULL && startup->socket_open!=NULL)
		startup->socket_open(startup->cbdata,FALSE);
	stats.sockets--;
	if(result!=0) {
		if(ERROR_VALUE!=ENOTSOCK)
			lprintf(LOG_WARNING,"%04d !ERROR %d closing socket",*sock, ERROR_VALUE);
	}
#if 0 /*def _DEBUG */
	else 
		lprintf(LOG_DEBUG,"%04d Socket closed (%d sockets in use)",*sock,stats.sockets);
#endif

	*sock = -1;

	return(result);
}

static void status(char* str)
{
	if(startup!=NULL && startup->status!=NULL)
	    startup->status(startup->cbdata,str);
}

int sockprintf(SOCKET sock, const char* prot, CRYPT_SESSION sess, char *fmt, ...)
{
	int		len;
	int		maxlen;
	int		result;
	va_list argptr;
	char	sbuf[1024];
	fd_set	socket_set;
	struct timeval tv;

    va_start(argptr,fmt);
    len=vsnprintf(sbuf,maxlen=sizeof(sbuf)-2,fmt,argptr);
    va_end(argptr);

	if(len<0 || len > maxlen) /* format error or output truncated */
		len=maxlen;
	if(startup->options&MAIL_OPT_DEBUG_TX)
		lprintf(LOG_DEBUG,"%04d %s TX: %.*s", sock, prot, len, sbuf);
	memcpy(sbuf+len,"\r\n",2);
	len+=2;

	if(sock==INVALID_SOCKET) {
		lprintf(LOG_WARNING,"%s !INVALID SOCKET in call to sockprintf", prot);
		return(0);
	}

	/* Check socket for writability (using select) */
	tv.tv_sec=300;
	tv.tv_usec=0;

	FD_ZERO(&socket_set);
	FD_SET(sock,&socket_set);

	if((result=select(sock+1,NULL,&socket_set,NULL,&tv))<1) {
		if(result==0)
			lprintf(LOG_NOTICE,"%04d %s !TIMEOUT selecting socket for send"
				,sock, prot);
		else
			lprintf(LOG_NOTICE,"%04d %s !ERROR %d selecting socket for send"
				,sock, prot, ERROR_VALUE);
		return(0);
	}

	if (sess != -1) {
		int tls_sent;
		int sent = 0;
		while (sent < len) {
			result = cryptPushData(sess, sbuf+sent, len-sent, &tls_sent);
			if (result == CRYPT_OK)
				sent += tls_sent;
			else {
				GCES(result, prot, sock, sess, "pushing data");
				return 0;
			}
		}
		if ((result = cryptFlushData(sess)) != CRYPT_OK) {
			GCES(result, prot, sock, sess, "flushing data");
			return 0;
		}
	}
	else {
		// It looks like this could stutter on partial sends -- Deuce
		while((result=sendsocket(sock,sbuf,len))!=len) {
			if(result==SOCKET_ERROR) {
				if(ERROR_VALUE==EWOULDBLOCK) {
					YIELD();
					continue;
				}
				if(ERROR_VALUE==ECONNRESET) 
					lprintf(LOG_NOTICE,"%04d %s Connection reset by peer on send",sock,prot);
				else if(ERROR_VALUE==ECONNABORTED) 
					lprintf(LOG_NOTICE,"%04d %s Connection aborted by peer on send",sock, prot);
				else
					lprintf(LOG_NOTICE,"%04d %s !ERROR %d sending on socket",sock,prot,ERROR_VALUE);
				return(0);
			}
			lprintf(LOG_WARNING,"%04d %s !ERROR: short send on socket: %d instead of %d",sock,prot,result,len);
		}
	}
	return(len);
}

static void sockerror(SOCKET socket, const char* prot, int rd, const char* action)
{
	if(rd==0) 
		lprintf(LOG_NOTICE,"%04d %s Socket closed by peer on %s"
			,socket, prot, action);
	else if(rd==SOCKET_ERROR) {
		if(ERROR_VALUE==ECONNRESET) 
			lprintf(LOG_NOTICE,"%04d %s Connection reset by peer on %s"
				,socket, prot, action);
		else if(ERROR_VALUE==ECONNABORTED) 
			lprintf(LOG_NOTICE,"%04d %s Connection aborted by peer on %s"
				,socket, prot, action);
		else
			lprintf(LOG_NOTICE,"%04d %s !SOCKET ERROR %d on %s"
				,socket, prot, ERROR_VALUE, action);
	} else
		lprintf(LOG_WARNING,"%04d %s !SOCKET ERROR: unexpected return value %d from %s"
			,socket, prot, rd, action);
}

static int sock_recvbyte(SOCKET sock, const char* prot, CRYPT_SESSION sess, char *buf, time_t start)
{
	int len=0;
	fd_set	socket_set;
	struct	timeval	tv;
	int ret;
	int i;

	if (sess > -1) {
		while (1) {
			ret = cryptPopData(sess, buf, 1, &len);
			GCES(ret, prot, sock, sess, "popping data");
			switch(ret) {
				case CRYPT_OK:
					break;
				case CRYPT_ERROR_TIMEOUT:
					return -1;
				case CRYPT_ERROR_COMPLETE:
					return 0;
				default:
					if (ret < -1)
						return ret;
					return -2;
			}
			if (len)
				return len;
			if(startup->max_inactivity && (time(NULL)-start)>startup->max_inactivity) {
				lprintf(LOG_WARNING,"%04d %s !TIMEOUT in sock_recvbyte (%u seconds):  INACTIVE SOCKET"
					,sock, prot, startup->max_inactivity);
				return(-1);
			}
		}
	}
	else {
		tv.tv_sec=startup->max_inactivity;
		tv.tv_usec=0;

		FD_ZERO(&socket_set);
		FD_SET(sock,&socket_set);

		i=select(sock+1,&socket_set,NULL,NULL,&tv);

		if(i<1) {
			if(i==0) {
				if(startup->max_inactivity && (time(NULL)-start)>startup->max_inactivity) {
					lprintf(LOG_WARNING,"%04d %s !TIMEOUT in sock_recvbyte (%u seconds):  INACTIVE SOCKET"
						,sock, prot, startup->max_inactivity);
					return(-1);
				}
				return 0;
			}
			sockerror(sock,prot,i,"select");
			return 0;
		}
		i=recv(sock, buf, 1, 0);
		if(i<1)
			sockerror(sock,prot,i,"receive");
		return i;
	}
}

static int sockreadline(SOCKET socket, const char* prot, CRYPT_SESSION sess, char* buf, int len)
{
	char	ch;
	int		i,rd=0;
	time_t	start;

	buf[0]=0;

	start=time(NULL);

	if(socket==INVALID_SOCKET) {
		lprintf(LOG_WARNING,"%s !INVALID SOCKET in call to sockreadline", prot);
		return(-1);
	}
	
	while(rd<len-1) {

		if(terminated || terminate_server) {
			lprintf(LOG_WARNING,"%04d %s !ABORTING sockreadline",socket, prot);
			return(-1);
		}

		i = sock_recvbyte(socket, prot, sess, &ch, start);

		if(i<1)
			return(-1);

		if(ch=='\n' /* && rd>=1 */ ) { /* Mar-9-2003: terminate on sole LF */
			break;
		}
		buf[rd++]=ch;
	}
	if(rd>0 && buf[rd-1]=='\r')
		rd--;
	buf[rd]=0;
	
	return(rd);
}

static BOOL sockgetrsp(SOCKET socket, const char* prot, CRYPT_SESSION sess, char* rsp, char *buf, int len)
{
	int rd;

	while(1) {
		rd = sockreadline(socket, prot, sess, buf, len);
		if(rd<1) {
			if(rd==0 && rsp != NULL)
				lprintf(LOG_WARNING,"%04d %s !RECEIVED BLANK RESPONSE, Expected '%s'", socket, prot, rsp);
			return(FALSE);
		}
		if(buf[3]=='-')	{ /* Multi-line response */
			if(startup->options&MAIL_OPT_DEBUG_RX_RSP) 
				lprintf(LOG_DEBUG,"%04d %s RX: %s",socket, prot, buf);
			continue;
		}
		if(rsp!=NULL && strnicmp(buf,rsp,strlen(rsp))) {
			lprintf(LOG_WARNING,"%04d %s !INVALID RESPONSE: '%s' Expected: '%s'", socket, prot, buf, rsp);
			return(FALSE);
		}
		break;
	}
	if(startup->options&MAIL_OPT_DEBUG_RX_RSP) 
		lprintf(LOG_DEBUG,"%04d %s RX: %s",socket, prot, buf);
	return(TRUE);
}

static int sockgetrsp_opt(SOCKET socket, const char* prot, CRYPT_SESSION sess, char* rsp, char *opt, char *buf, int len)
{
	int rd;
	int ret = 0;
	size_t moptlen;
	char *mopt;

	moptlen = strlen(rsp)+strlen(opt) + 1;
	mopt = malloc(moptlen+1);
	if (mopt == NULL)
		return -1;
	sprintf(mopt, "%s-%s", rsp, opt);
	while(1) {
		rd = sockreadline(socket, prot, sess, buf, len);
		if(rd<1) {
			if(rd==0)
				lprintf(LOG_WARNING,"%04d %s !RECEIVED BLANK RESPONSE, Expected '%s'", socket, prot, rsp);
			free(mopt);
			return(-1);
		}
		if(buf[3]=='-')	{ /* Multi-line response */
			if (strncmp(buf, mopt, moptlen) == 0)
				ret = 1;
			if(startup->options&MAIL_OPT_DEBUG_RX_RSP) 
				lprintf(LOG_DEBUG,"%04d %s RX: %s",socket, prot, buf);
			continue;
		}
		if(strnicmp(buf,rsp,strlen(rsp))) {
			lprintf(LOG_WARNING,"%04d %s !INVALID RESPONSE: '%s' Expected: '%s'", socket, prot, buf, rsp);
			free(mopt);
			return(-1);
		}
		break;
	}
	mopt[strlen(rsp)] = ' ';
	if (strncmp(buf, mopt, moptlen) == 0)
		ret = 1;
	free(mopt);
	if(startup->options&MAIL_OPT_DEBUG_RX_RSP)
		lprintf(LOG_DEBUG,"%04d %s RX: %s",socket, prot, buf);
	return(ret);
}

/* non-standard, but documented (mostly) in draft-newman-msgheader-originfo-05 */
void originator_info(SOCKET socket, const char* protocol, CRYPT_SESSION sess, smbmsg_t* msg)
{
	char* user		= msg->from_ext;
	char* login		= smb_get_hfield(msg,SENDERUSERID,NULL);
	char* server	= smb_get_hfield(msg,SENDERSERVER,NULL);
	char* client	= smb_get_hfield(msg,SENDERHOSTNAME,NULL);
	char* addr		= smb_get_hfield(msg,SENDERIPADDR,NULL);
	char* prot		= smb_get_hfield(msg,SENDERPROTOCOL,NULL);
	char* port		= smb_get_hfield(msg,SENDERPORT,NULL);
	char* time		= smb_get_hfield(msg,SENDERTIME,NULL);

	if(user || login || server || client || addr || prot || port || time)
		sockprintf(socket, protocol, sess
			,"X-Originator-Info: account=%s; login-id=%s; server=%s; client=%s; addr=%s; prot=%s; port=%s; time=%s"
			,user
			,login
			,server
			,client
			,addr
			,prot
			,port
			,time
			);
}

char* angle_bracket(char* buf, size_t max, const char* addr)
{
	if(*addr == '<')
		safe_snprintf(buf, max, "%s", addr);
	else
		safe_snprintf(buf, max, "<%s>", addr);
	return buf;
}

int compare_addrs(const char* addr1, const char* addr2)
{
	char tmp1[256];
	char tmp2[256];

	return strcmp(angle_bracket(tmp1, sizeof(tmp1), addr1), angle_bracket(tmp2, sizeof(tmp2), addr2));
}

/* RFC822: The maximum total length of a text line including the
   <CRLF> is 1000 characters (but not counting the leading
   dot duplicated for transparency). 

   POP3 (RFC1939) actually calls for a 512 byte line length limit!
*/
#define MAX_LINE_LEN	998		

static ulong sockmimetext(SOCKET socket, const char* prot, CRYPT_SESSION sess, smbmsg_t* msg, char* msgtxt, ulong maxlines
						  ,str_list_t file_list, char* mime_boundary)
{
	char		toaddr[256]="";
	char		fromaddr[256]="";
	char		fromhost[256];
	char		msgid[256];
	char		tmp[256];
	char		date[64];
	char*		p;
	char*		np;
	int			i;
	int			s;
	ulong		lines;
	int			len,tlen;

	/* HEADERS (in recommended order per RFC822 4.1) */

	if(msg->reverse_path!=NULL)
		if(!sockprintf(socket,prot,sess,"Return-Path: %s", msg->reverse_path))
			return(0);

	for(i=0;i<msg->total_hfields;i++)
		if(msg->hfield[i].type == SMTPRECEIVED && msg->hfield_dat[i]!=NULL) 
			if(!sockprintf(socket,prot,sess,"Received: %s", (char*)msg->hfield_dat[i]))
				return(0);

	if(!sockprintf(socket,prot,sess,"Date: %s",msgdate(msg->hdr.when_written,date)))
		return(0);

	if((p=smb_get_hfield(msg,RFC822FROM,NULL))!=NULL)
		s=sockprintf(socket,prot,sess,"From: %s",p);	/* use original RFC822 header field */
	else {
		char fromname[256];
		SAFEPRINTF(fromname, "\"%s\"", msg->from);
		if(msg->from_net.type==NET_QWK && msg->from_net.addr!=NULL)
			SAFEPRINTF2(fromaddr,"%s!%s"
				,(char*)msg->from_net.addr
				,usermailaddr(&scfg,fromhost,msg->from));
		else if(msg->from_net.type==NET_FIDO && msg->from_net.addr!=NULL) {
			faddr_t* faddr = (faddr_t *)msg->from_net.addr;
			char faddrstr[128];
			SAFEPRINTF2(fromname,"\"%s\" (%s)", msg->from, smb_faddrtoa(faddr, NULL));
			if(faddr->point)
				SAFEPRINTF4(faddrstr,"p%hu.f%hu.n%hu.z%hu"FIDO_TLD
					,faddr->point, faddr->node, faddr->net, faddr->zone);
			else
				SAFEPRINTF3(faddrstr,"f%hu.n%hu.z%hu"FIDO_TLD
					,faddr->node, faddr->net, faddr->zone);
			SAFEPRINTF2(fromaddr,"%s@%s", usermailaddr(NULL,fromhost,msg->from), faddrstr);
		} else if(msg->from_net.type!=NET_NONE && msg->from_net.addr!=NULL)
			SAFECOPY(fromaddr,(char*)msg->from_net.addr);
		else 
			usermailaddr(&scfg,fromaddr,msg->from);
		s = sockprintf(socket,prot,sess,"From: %s %s", fromname, angle_bracket(tmp, sizeof(tmp), fromaddr));
	}
	if(!s)
		return(0);

	if((p = smb_get_hfield(msg, RFC822ORG, NULL)) != NULL) {
		if(!sockprintf(socket,prot,sess,"Organization: %s", p))
			return(0);
	} else {
		if(msg->from_org!=NULL || msg->from_net.type==NET_NONE)
			if(!sockprintf(socket,prot,sess,"Organization: %s"
				,msg->from_org==NULL ? scfg.sys_name : msg->from_org))
				return(0);
	}

	p = smb_get_hfield(msg, RFC822SUBJECT, NULL);
	if(!sockprintf(socket,prot,sess,"Subject: %s", p == NULL ? msg->subj : p))
		return(0);

	if((p = smb_get_hfield(msg, RFC822TO, NULL)) != NULL)
		s=sockprintf(socket,prot,sess,"To: %s", p);	/* use original RFC822 header field (MIME-Encoded) */
	else if((p = msg->to_list) != NULL)
		s=sockprintf(socket,prot,sess,"To: %s", p);	/* use original RFC822 header field */
	else {
		if(strchr(msg->to,'@')!=NULL || msg->to_net.addr==NULL)
			s=sockprintf(socket,prot,sess,"To: %s",msg->to);	/* Avoid double-@ */
		else if(msg->to_net.type==NET_INTERNET || msg->to_net.type==NET_QWK) {
			if(strchr((char*)msg->to_net.addr,'<')!=NULL)
				s=sockprintf(socket,prot,sess,"To: %s",(char*)msg->to_net.addr);
			else
				s=sockprintf(socket,prot,sess,"To: \"%s\" <%s>",msg->to,(char*)msg->to_net.addr);
		} else if(msg->to_net.type==NET_FIDO) {
			s=sockprintf(socket,prot,sess,"To: \"%s\" (%s)",msg->to, smb_faddrtoa((fidoaddr_t*)msg->to_net.addr, NULL));
		} else {
			usermailaddr(&scfg,toaddr,msg->to);
			s=sockprintf(socket,prot,sess,"To: \"%s\" <%s>",msg->to,toaddr);
		}
	}
	if(!s)
		return(0);
	if((p = smb_get_hfield(msg, RFC822CC, NULL)) != NULL || msg->cc_list != NULL)
		if(!sockprintf(socket,prot,sess,"Cc: %s", p == NULL ? msg->cc_list : p))
			return(0);
	np=NULL;
	p = smb_get_hfield(msg, RFC822REPLYTO, NULL);
	if(p == NULL && (p = msg->replyto_list) == NULL) {
		np=msg->replyto;
		if(msg->replyto_net.type==NET_INTERNET)
			p=msg->replyto_net.addr;
	}
	if(p!=NULL && strchr((char*)p, '@') != NULL) {
		if(np!=NULL)
			s=sockprintf(socket,prot,sess,"Reply-To: \"%s\" <%s>",np,p);
		else 
			s=sockprintf(socket,prot,sess,"Reply-To: %s",p);
	}
	if(!s)
		return(0);
	if(!sockprintf(socket,prot,sess,"Message-ID: %s",get_msgid(&scfg,INVALID_SUB,msg,msgid,sizeof(msgid))))
		return(0);
	if(msg->reply_id!=NULL)
		if(!sockprintf(socket,prot,sess,"In-Reply-To: %s",msg->reply_id))
			return(0);

	if(msg->hdr.priority != SMB_PRIORITY_UNSPECIFIED)
		if(!sockprintf(socket,prot,sess,"X-Priority: %u", (uint)msg->hdr.priority))
			return(0);

	originator_info(socket, prot, sess, msg);

	/* Include all possible FidoNet header fields here */
	for(i=0;i<msg->total_hfields;i++) {
		switch(msg->hfield[i].type) {
			case FIDOCTRL:
			case FIDOAREA:	
			case FIDOSEENBY:
			case FIDOPATH:
			case FIDOMSGID:
			case FIDOREPLYID:
			case FIDOPID:
			case FIDOFLAGS:
			case FIDOTID:
				if(!sockprintf(socket, prot, sess, "%s: %s", smb_hfieldtype(msg->hfield[i].type), (char*)msg->hfield_dat[i]))
					return(0);
				break;
		}
	}
	for(i=0;i<msg->total_hfields;i++) { 
		if(msg->hfield[i].type==RFC822HEADER) { 
			if(!sockprintf(socket,prot, sess,"%s",(char*)msg->hfield_dat[i]))
				return(0);
        }
    }
	const char* charset = msg->text_charset;
	if(charset == NULL) {
		if(smb_msg_is_utf8(msg) || (msg->hdr.auxattr & MSG_HFIELDS_UTF8))
			charset = "UTF-8";
		else if(str_is_ascii(msgtxt))
			charset = "US-ASCII";
		else
			charset = "IBM437";
	}

	if(strListCount(file_list)) {	/* File attachments */
        mimeheaders(socket,prot,sess,mime_boundary);
        sockprintf(socket,prot,sess,"");
        mimeblurb(socket,prot,sess,mime_boundary);
        sockprintf(socket,prot,sess,"");
        mimetextpartheader(socket,prot,sess,mime_boundary, msg->text_subtype, charset);
	} else {
		/* Default MIME Content-Type for non-Internet messages */
		if(msg->from_net.type!=NET_INTERNET && msg->content_type==NULL) {
			sockprintf(socket,prot,sess, "Content-Type: text/plain; charset=%s", charset);
			sockprintf(socket,prot,sess, "Content-Transfer-Encoding: 8bit");
		}
	}
	if(!sockprintf(socket,prot,sess,""))	/* Header Terminator */
		return(0);

	/* MESSAGE BODY */
	lines=0;
	np=msgtxt;
	while(*np && lines<maxlines) {
		len=0;
		while(len<MAX_LINE_LEN && *(np+len)!=0 && *(np+len)!='\n')
			len++;

		tlen=len;
		while(tlen && *(np+(tlen-1))<=' ') /* Takes care of '\r' or spaces */
			tlen--;

		if(!sockprintf(socket,prot,sess, "%s%.*s", *np=='.' ? ".":"", tlen, np))
			break;
		lines++;
		if(*(np+len)=='\r')
			len++;
		if(*(np+len)=='\n')
			len++;
		np+=len;
		/* release time-slices every x lines */
		if(startup->lines_per_yield
			&& !(lines%startup->lines_per_yield))	
			YIELD();
		if((lines%100) == 0)
			lprintf(LOG_DEBUG,"%04d %s sent %lu lines (%ld bytes) of body text"
				,socket, prot, lines, (long)(np-msgtxt));
	}
	lprintf(LOG_DEBUG,"%04d %s sent %lu lines (%ld bytes) of body text"
		,socket, prot, lines, (long)(np-msgtxt));
	if(file_list!=NULL) {
		for(i=0;file_list[i];i++) { 
			sockprintf(socket,prot,sess,"");
			lprintf(LOG_INFO,"%04u %s MIME Encoding and sending %s", socket, prot, file_list[i]);
			if(!mimeattach(socket,prot,sess,mime_boundary,file_list[i]))
				lprintf(LOG_ERR,"%04u %s !ERROR opening/encoding/sending %s", socket, prot, file_list[i]);
			else {
				if(msg->hdr.auxattr&MSG_KILLFILE)
					if(remove(file_list[i])!=0)
						lprintf(LOG_WARNING,"%04u %s !ERROR %d (%s) removing %s", socket, prot, errno, strerror(errno), file_list[i]);
			}
			endmime(socket,prot,sess,mime_boundary);
		}
	}
    sockprintf(socket,prot,sess,".");	/* End of text */
	return(lines);
}

static ulong sockmsgtxt(SOCKET socket, const char* prot, CRYPT_SESSION sess, smbmsg_t* msg, char* msgtxt, ulong maxlines)
{
	char		dirname[MAX_PATH + 1];
	char		filepath[MAX_PATH + 1];
	ulong		retval;
	char*		boundary=NULL;
	str_list_t	file_list=NULL;

	if(msg->hdr.auxattr&MSG_FILEATTACH) {
		if(msg->idx.to != 0)
			SAFEPRINTF2(dirname, "%sfile/%04u.in", scfg.data_dir, msg->idx.to);
		else
			SAFEPRINTF2(dirname, "%sfile/%04u.out", scfg.data_dir, msg->idx.from);

		boundary = mimegetboundary();
		file_list = strListInit();

		/* filename(s) in subject */
		char* p = msg->subj;
		SKIP_WHITESPACE(p);
		while(*p != '\0') {
			char delim = ' ';
			if(*p == '"') {
				delim = '"';
				p++;
			}
			char* tp = strchr(p, delim);
			if(tp == NULL) {
				if(delim != ' ')
					break;
			} else
				*tp = '\0';
			char* fname = getfname(truncsp(p));
			if(strcspn(fname, ILLEGAL_FILENAME_CHARS) == strlen(fname)) {
				SAFEPRINTF2(filepath, "%s/%s", dirname, fname);
				strListPush(&file_list, filepath);
			}
			if(tp == NULL)
				break;
			p = tp + 1;
			SKIP_WHITESPACE(p);
		}
    }

	retval = sockmimetext(socket,prot,sess,msg,msgtxt,maxlines,file_list,boundary);

	strListFree(&file_list);

	if(boundary!=NULL)
		free(boundary);

	return(retval);
}

static u_long resolve_ip(const char *inaddr)
{
	char*		p;
	char*		addr;
	char		buf[128];
	HOSTENT*	host;

	SAFECOPY(buf,inaddr);
	addr=buf;
	if(*addr=='[' && *(p=lastchar(addr))==']') { /* Support [ip_address] notation */
		addr++;
		*p=0;
	}

	if(*addr==0)
		return((u_long)INADDR_NONE);

	for(p=addr;*p;p++)
		if(*p!='.' && !IS_DIGIT(*p))
			break;
	if(!(*p))
		return(inet_addr(addr));

	if((host=gethostbyname(inaddr))==NULL)
		return((u_long)INADDR_NONE);

	return(*((ulong*)host->h_addr_list[0]));
}

/****************************************************************************/
/* Consecutive failed login (possible password hack) attempt tracking		*/
/****************************************************************************/
/* Counter is global so it is tracked between multiple connections.			*/
/* Failed consecutive login attempts > 10 will generate a hacklog entry	and	*/
/* immediately disconnect (after the usual failed-login delay).				*/
/* A failed login from a different host resets the counter.					*/
/* A successful login from the same host resets the counter.				*/
/****************************************************************************/

static void badlogin(SOCKET sock, CRYPT_SESSION sess, const char* prot, const char* resp, char* user, char* passwd, char* host, union xp_sockaddr* addr)
{
	char	reason[128];
	char	ip[INET6_ADDRSTRLEN];
	ulong	count;
	
	if(user == NULL)
		user = "<unspecified>";

	if(addr!=NULL) {
		SAFEPRINTF(reason,"%s LOGIN", prot);
		count=loginFailure(startup->login_attempt_list, addr, prot, user, passwd);
		if(startup->login_attempt.hack_threshold && count>=startup->login_attempt.hack_threshold)
			hacklog(&scfg, reason, user, passwd, host, addr);
		inet_addrtop(addr, ip, sizeof(ip));
		if(startup->login_attempt.filter_threshold && count>=startup->login_attempt.filter_threshold) {
			SAFEPRINTF(reason, "- TOO MANY CONSECUTIVE FAILED LOGIN ATTEMPTS (%lu)", count);
			filter_ip(&scfg, (char*)prot, reason ,host, ip, user, /* fname: */NULL);
		}
	}

	mswait(startup->login_attempt.delay);
	sockprintf(sock,prot,sess, "%s", resp);
}

static void pop3_thread(void* arg)
{
	char*		p;
	char		str[128];
	char		buf[512];