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SMTPSERV.C
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C/C++ Source or Header
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1988-07-28
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13KB
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595 lines
/* SMTP Server state machine - see RFC 821
* Very simple implementation; no forwarding allowed
* (who wants to re-create "sendmail" ??)
* enhanced 12/87 Dave Trulli nn2z
*/
#include <stdio.h>
#include <ctype.h>
#include <time.h>
#include "global.h"
#include "mbuf.h"
#include "netuser.h"
#include "timer.h"
#include "tcp.h"
#include "smtp.h"
#ifndef DFLT_MODE
#define DFLT_MODE 0660 /* use this instead of user's umask */
#endif
char *ptime(), *getname();
void mail_delete(), del_rcpt();
static int queuejob(),checkaddress();
int32 get_msgid();
/* Command table */
static char *commands[] = {
"helo",
#define HELO_CMD 0
"noop",
#define NOOP_CMD 1
"mail from:",
#define MAIL_CMD 2
"quit",
#define QUIT_CMD 3
"rcpt to:",
#define RCPT_CMD 4
"help",
#define HELP_CMD 5
"data",
#define DATA_CMD 6
"rset",
#define RSET_CMD 7
NULLCHAR
};
/* Reply messages */
static char help[] = "214-Commands:\r\n214-HELO NOOP MAIL QUIT RCPT HELP DATA RSET\r\n214 End\r\n";
static char banner[] = "220 %s SMTP ready\r\n";
static char closing[] = "221 Closing\r\n";
static char ok[] = "250 Ok\r\n";
static char reset[] = "250 Reset state\r\n";
static char sent[] = "250 Sent\r\n";
static char ourname[] = "250 %s, \"Gateway to the universe!\"\r\n"; /*Share and Enjoy!\r\n";*/
static char enter[] = "354 Enter mail, end with .\r\n";
static char ioerr[] = "452 Temp file write error\r\n";
static char mboxerr[] = "452 Mailbox %s write error\r\n";
static char badcmd[] = "500 Command unrecognized\r\n";
static char syntax[] = "501 Syntax error\r\n";
static char needrcpt[] = "503 Need RCPT (recipient)\r\n";
static char badname[] = "550 Can't open mailbox for %s\r\n";
static struct tcb *smtp_tcb;
/* Start up SMTP receiver service */
smtp_start(argc,argv)
int argc;
char *argv[];
{
struct socket lsocket;
void r_mail(),s_mail();
lsocket.address = ip_addr;
if(argc < 2)
lsocket.port = SMTP_PORT;
else
lsocket.port = atoi(argv[1]);
smtp_tcb = open_tcp(&lsocket,NULLSOCK,
TCP_SERVER,0,r_mail,NULLVFP,s_mail,0,(char *)NULL);
}
/* Shutdown SMTP service (existing connections are allowed to finish) */
smtp_stop()
{
if(smtp_tcb != NULLTCB)
close_tcp(smtp_tcb);
}
/* SMTP connection state change upcall handler */
static void
s_mail(tcb,old,new)
struct tcb *tcb;
char old,new;
{
struct mail *mp,*mail_create();
switch(new){
#ifdef QUICKSTART
case SYN_RECEIVED:
#else
case ESTABLISHED:
#endif
if((mp = mail_create(tcb)) == NULLMAIL){
close_tcp(tcb);
break;
}
(void) tprintf(mp->tcb,banner,hostname);
log(tcb,"open SMTP");
break;
case CLOSE_WAIT:
close_tcp(tcb);
break;
case CLOSED:
log(tcb,"close SMTP");
mp = (struct mail *)tcb->user;
mail_delete(mp);
del_tcp(tcb);
/* Check if server is being shut down */
if(tcb == smtp_tcb)
smtp_tcb = NULLTCB;
break;
}
}
/* SMTP receiver upcall handler */
static void
r_mail(tcb,cnt)
struct tcb *tcb;
int16 cnt;
{
register struct mail *mp;
char *inet_ntoa(),c;
struct mbuf *bp;
void docommand(),deliver(),doline();
if((mp = (struct mail *)tcb->user) == NULLMAIL){
/* Unknown session */
close_tcp(tcb);
return;
}
recv_tcp(tcb,&bp,cnt);
/* Assemble an input line in the session buffer.
* Return if incomplete
*/
while(pullup(&bp,&c,1) == 1){
switch(c){
case '\r': /* Strip cr's */
#ifdef MSDOS
case '\032': /* Strip ctrl/Z's */
#endif
continue;
case '\n': /* Complete line; process it */
mp->buf[mp->cnt] = '\0';
doline(mp);
break;
default: /* Assemble line */
if(mp->cnt != LINELEN-1)
mp->buf[mp->cnt++] = c;
break;
}
}
}
/* Process a line read on an SMTP connection (any state) */
static void
doline(mp)
register struct mail *mp;
{
void docommand(),deliver();
switch(mp->state){
case COMMAND_STATE:
docommand(mp);
break;
case DATA_STATE:
tcp_output(mp->tcb); /* Send ACK; disk I/O is slow */
if(mp->buf[0] == '.' && mp->buf[1] == '\0'){
mp->state = COMMAND_STATE;
deliver(mp); /* Also sends appropriate response */
break;
}
/* Append to data file */
if(fprintf(mp->data,"%s\n",mp->buf) < 0){
mp->state = COMMAND_STATE;
(void) tprintf(mp->tcb,ioerr);
}
break;
}
mp->cnt = 0;
}
/* Create control block, initialize */
static struct mail *
mail_create(tcb)
register struct tcb *tcb;
{
register struct mail *mp;
if((mp = (struct mail *)calloc(1,sizeof (struct mail))) == NULLMAIL)
return NULLMAIL;
mp->tcb = tcb; /* Downward pointer */
tcb->user = (char *)mp; /* Upward pointer */
return mp;
}
/* Free resources, delete control block */
static void
mail_delete(mp)
register struct mail *mp;
{
if (mp == NULLMAIL)
return;
if(mp->system != NULLCHAR)
free(mp->system);
if(mp->from != NULLCHAR)
free(mp->from);
if(mp->data != NULLFILE)
fclose(mp->data);
del_rcpt(mp->to);
free((char *)mp);
}
static void
del_rcpt(p)
struct addr *p;
{
register struct addr *ap,*ap1;
for(ap = p;ap != NULLADDR;ap = ap1){
if(ap->val != NULLCHAR)
free(ap->val);
ap1 = ap->next;
free((char *)ap);
}
}
/* Parse and execute mail commands */
static void
docommand(mp)
register struct mail *mp;
{
char *cmd,*arg,*cp,**cmdp;
struct addr *ap;
FILE *tmpfile();
long t;
cmd = mp->buf;
if(mp->cnt < 4){
/* Can't be a legal SMTP command */
(void) tprintf(mp->tcb,badcmd);
return;
}
cmd = mp->buf;
/* Translate entire buffer to lower case */
for(cp = cmd;*cp != '\0';cp++)
*cp = tolower(*cp);
/* Find command in table; if not present, return syntax error */
for(cmdp = commands;*cmdp != NULLCHAR;cmdp++)
if(strncmp(*cmdp,cmd,strlen(*cmdp)) == 0)
break;
if(*cmdp == NULLCHAR){
(void) tprintf(mp->tcb,badcmd);
return;
}
arg = &cmd[strlen(*cmdp)];
/* Skip spaces after command */
while(*arg == ' ')
arg++;
/* Execute specific command */
switch(cmdp-commands){
case HELO_CMD:
if(mp->system != NULLCHAR)
free(mp->system);
if((mp->system = malloc((unsigned)strlen(arg)+1)) == NULLCHAR){
/* If the system is out of memory, just close */
close_tcp(mp->tcb);
break;
} else {
strcpy(mp->system,arg);
(void) tprintf(mp->tcb,ourname,hostname);
}
break;
case NOOP_CMD:
(void) tprintf(mp->tcb,ok);
break;
case MAIL_CMD:
if(mp->from != NULLCHAR)
free(mp->from);
if((mp->from = malloc((unsigned)strlen(arg)+1)) == NULLCHAR){
/* If the system is out of memory, just close */
close_tcp(mp->tcb);
break;
} else {
if((cp = getname(arg)) == NULLCHAR){
(void) tprintf(mp->tcb,syntax);
break;
}
strcpy(mp->from,cp);
(void) tprintf(mp->tcb,ok);
}
break;
case QUIT_CMD:
(void) tprintf(mp->tcb,closing);
close_tcp(mp->tcb);
break;
case RCPT_CMD: /* Specify recipient */
if((cp = getname(arg)) == NULLCHAR){
(void) tprintf(mp->tcb,syntax);
break;
}
if (checkaddress(cp)) {
(void) tprintf(mp->tcb,badname,cp);
break;
}
/* Allocate an entry on the recipient list. This
* assembles the list backwards, but what the heck.
*/
if((ap = (struct addr *)malloc(sizeof(struct addr))) == NULLADDR){
close_tcp(mp->tcb);
break;
}
if((ap->val = malloc((unsigned)strlen(cp)+1)) == NULLCHAR){
free((char *)ap);
close_tcp(mp->tcb);
break;
}
strcpy(ap->val,cp);
ap->next = mp->to;
mp->to = ap;
(void) tprintf(mp->tcb,ok);
break;
case HELP_CMD:
(void) tprintf(mp->tcb,help);
break;
case DATA_CMD:
if(mp->to == NULLADDR){
(void) tprintf(mp->tcb,needrcpt);
break;
}
tcp_output(mp->tcb); /* Send ACK; disk I/O is slow */
if((mp->data = tmpfile()) == NULLFILE){
(void) tprintf(mp->tcb,ioerr);
break;
}
/* Add timestamp; ptime adds newline */
mp->seqn = get_msgid();
time(&t);
fprintf(mp->data,"Received: ");
if(mp->system != NULLCHAR)
fprintf(mp->data,"from %s ",mp->system);
fprintf(mp->data,"by %s with SMTP (871225.4/ST)\n\tid %ld; %s",
hostname,
mp->seqn,
ptime(&t));
if(ferror(mp->data)){
(void) tprintf(mp->tcb,ioerr);
} else {
mp->state = DATA_STATE;
(void) tprintf(mp->tcb,enter);
}
break;
case RSET_CMD:
del_rcpt(mp->to);
mp->to = NULLADDR;
mp->state = COMMAND_STATE;
(void) tprintf(mp->tcb,reset);
break;
}
}
/* Given a string of the form <user@host>, extract the p