--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/qmail-smtpd.c	Fri Oct 19 14:06:22 2007 +0200
@@ -0,0 +1,421 @@
+#include "sig.h"
+#include "readwrite.h"
+#include "stralloc.h"
+#include "substdio.h"
+#include "alloc.h"
+#include "auto_qmail.h"
+#include "control.h"
+#include "received.h"
+#include "constmap.h"
+#include "error.h"
+#include "ipme.h"
+#include "ip.h"
+#include "qmail.h"
+#include "str.h"
+#include "fmt.h"
+#include "scan.h"
+#include "byte.h"
+#include "case.h"
+#include "env.h"
+#include "now.h"
+#include "exit.h"
+#include "rcpthosts.h"
+#include "timeoutread.h"
+#include "timeoutwrite.h"
+#include "commands.h"
+
+#define MAXHOPS 100
+unsigned int databytes = 0;
+int timeout = 1200;
+
+int safewrite(fd,buf,len) int fd; char *buf; int len;
+{
+  int r;
+  r = timeoutwrite(timeout,fd,buf,len);
+  if (r <= 0) _exit(1);
+  return r;
+}
+
+char ssoutbuf[512];
+substdio ssout = SUBSTDIO_FDBUF(safewrite,1,ssoutbuf,sizeof ssoutbuf);
+
+void flush() { substdio_flush(&ssout); }
+void out(s) char *s; { substdio_puts(&ssout,s); }
+
+void die_read() { _exit(1); }
+void die_alarm() { out("451 timeout (#4.4.2)\r\n"); flush(); _exit(1); }
+void die_nomem() { out("421 out of memory (#4.3.0)\r\n"); flush(); _exit(1); }
+void die_control() { out("421 unable to read controls (#4.3.0)\r\n"); flush(); _exit(1); }
+void die_ipme() { out("421 unable to figure out my IP addresses (#4.3.0)\r\n"); flush(); _exit(1); }
+void straynewline() { out("451 See http://pobox.com/~djb/docs/smtplf.html.\r\n"); flush(); _exit(1); }
+
+void err_bmf() { out("553 sorry, your envelope sender is in my badmailfrom list (#5.7.1)\r\n"); }
+void err_nogateway() { out("553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)\r\n"); }
+void err_unimpl() { out("502 unimplemented (#5.5.1)\r\n"); }
+void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); }
+void err_wantmail() { out("503 MAIL first (#5.5.1)\r\n"); }
+void err_wantrcpt() { out("503 RCPT first (#5.5.1)\r\n"); }
+void err_noop() { out("250 ok\r\n"); }
+void err_vrfy() { out("252 send some mail, i'll try my best\r\n"); }
+void err_qqt() { out("451 qqt failure (#4.3.0)\r\n"); }
+
+
+stralloc greeting = {0};
+
+void smtp_greet(code) char *code;
+{
+  substdio_puts(&ssout,code);
+  substdio_put(&ssout,greeting.s,greeting.len);
+}
+void smtp_help()
+{
+  out("214 qmail home page: http://pobox.com/~djb/qmail.html\r\n");
+}
+void smtp_quit()
+{
+  smtp_greet("221 "); out("\r\n"); flush(); _exit(0);
+}
+
+char *remoteip;
+char *remotehost;
+char *remoteinfo;
+char *local;
+char *relayclient;
+
+stralloc helohost = {0};
+char *fakehelo; /* pointer into helohost, or 0 */
+
+void dohelo(arg) char *arg; {
+  if (!stralloc_copys(&helohost,arg)) die_nomem(); 
+  if (!stralloc_0(&helohost)) die_nomem(); 
+  fakehelo = case_diffs(remotehost,helohost.s) ? helohost.s : 0;
+}
+
+int liphostok = 0;
+stralloc liphost = {0};
+int bmfok = 0;
+stralloc bmf = {0};
+struct constmap mapbmf;
+
+void setup()
+{
+  char *x;
+  unsigned long u;
+ 
+  if (control_init() == -1) die_control();
+  if (control_rldef(&greeting,"control/smtpgreeting",1,(char *) 0) != 1)
+    die_control();
+  liphostok = control_rldef(&liphost,"control/localiphost",1,(char *) 0);
+  if (liphostok == -1) die_control();
+  if (control_readint(&timeout,"control/timeoutsmtpd") == -1) die_control();
+  if (timeout <= 0) timeout = 1;
+
+  if (rcpthosts_init() == -1) die_control();
+
+  bmfok = control_readfile(&bmf,"control/badmailfrom",0);
+  if (bmfok == -1) die_control();
+  if (bmfok)
+    if (!constmap_init(&mapbmf,bmf.s,bmf.len,0)) die_nomem();
+ 
+  if (control_readint(&databytes,"control/databytes") == -1) die_control();
+  x = env_get("DATABYTES");
+  if (x) { scan_ulong(x,&u); databytes = u; }
+  if (!(databytes + 1)) --databytes;
+ 
+  remoteip = env_get("TCPREMOTEIP");
+  if (!remoteip) remoteip = "unknown";
+  local = env_get("TCPLOCALHOST");
+  if (!local) local = env_get("TCPLOCALIP");
+  if (!local) local = "unknown";
+  remotehost = env_get("TCPREMOTEHOST");
+  if (!remotehost) remotehost = "unknown";
+  remoteinfo = env_get("TCPREMOTEINFO");
+  relayclient = env_get("RELAYCLIENT");
+  dohelo(remotehost);
+}
+
+
+stralloc addr = {0}; /* will be 0-terminated, if addrparse returns 1 */
+
+int addrparse(arg)
+char *arg;
+{
+  int i;
+  char ch;
+  char terminator;
+  struct ip_address ip;
+  int flagesc;
+  int flagquoted;
+ 
+  terminator = '>';
+  i = str_chr(arg,'<');
+  if (arg[i])
+    arg += i + 1;
+  else { /* partner should go read rfc 821 */
+    terminator = ' ';
+    arg += str_chr(arg,':');
+    if (*arg == ':') ++arg;
+    while (*arg == ' ') ++arg;
+  }
+
+  /* strip source route */
+  if (*arg == '@') while (*arg) if (*arg++ == ':') break;
+
+  if (!stralloc_copys(&addr,"")) die_nomem();
+  flagesc = 0;
+  flagquoted = 0;
+  for (i = 0;ch = arg[i];++i) { /* copy arg to addr, stripping quotes */
+    if (flagesc) {
+      if (!stralloc_append(&addr,&ch)) die_nomem();
+      flagesc = 0;
+    }
+    else {
+      if (!flagquoted && (ch == terminator)) break;
+      switch(ch) {
+        case '\\': flagesc = 1; break;
+        case '"': flagquoted = !flagquoted; break;
+        default: if (!stralloc_append(&addr,&ch)) die_nomem();
+      }
+    }
+  }
+  /* could check for termination failure here, but why bother? */
+  if (!stralloc_append(&addr,"")) die_nomem();
+
+  if (liphostok) {
+    i = byte_rchr(addr.s,addr.len,'@');
+    if (i < addr.len) /* if not, partner should go read rfc 821 */
+      if (addr.s[i + 1] == '[')
+        if (!addr.s[i + 1 + ip_scanbracket(addr.s + i + 1,&ip)])
+          if (ipme_is(&ip)) {
+            addr.len = i + 1;
+            if (!stralloc_cat(&addr,&liphost)) die_nomem();
+            if (!stralloc_0(&addr)) die_nomem();
+          }
+  }
+
+  if (addr.len > 900) return 0;
+  return 1;
+}
+
+int bmfcheck()
+{
+  int j;
+  if (!bmfok) return 0;
+  if (constmap(&mapbmf,addr.s,addr.len - 1)) return 1;
+  j = byte_rchr(addr.s,addr.len,'@');
+  if (j < addr.len)
+    if (constmap(&mapbmf,addr.s + j,addr.len - j - 1)) return 1;
+  return 0;
+}
+
+int addrallowed()
+{
+  int r;
+  r = rcpthosts(addr.s,str_len(addr.s));
+  if (r == -1) die_control();
+  return r;
+}
+
+
+int seenmail = 0;
+int flagbarf; /* defined if seenmail */
+stralloc mailfrom = {0};
+stralloc rcptto = {0};
+
+void smtp_helo(arg) char *arg;
+{
+  smtp_greet("250 "); out("\r\n");
+  seenmail = 0; dohelo(arg);
+}
+void smtp_ehlo(arg) char *arg;
+{
+  smtp_greet("250-"); out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n");
+  seenmail = 0; dohelo(arg);
+}
+void smtp_rset()
+{
+  seenmail = 0;
+  out("250 flushed\r\n");
+}
+void smtp_mail(arg) char *arg;
+{
+  if (!addrparse(arg)) { err_syntax(); return; }
+  flagbarf = bmfcheck();
+  seenmail = 1;
+  if (!stralloc_copys(&rcptto,"")) die_nomem();
+  if (!stralloc_copys(&mailfrom,addr.s)) die_nomem();
+  if (!stralloc_0(&mailfrom)) die_nomem();
+  out("250 ok\r\n");
+}
+void smtp_rcpt(arg) char *arg; {
+  if (!seenmail) { err_wantmail(); return; }
+  if (!addrparse(arg)) { err_syntax(); return; }
+  if (flagbarf) { err_bmf(); return; }
+  if (relayclient) {
+    --addr.len;
+    if (!stralloc_cats(&addr,relayclient)) die_nomem();
+    if (!stralloc_0(&addr)) die_nomem();
+  }
+  else
+    if (!addrallowed()) { err_nogateway(); return; }
+  if (!stralloc_cats(&rcptto,"T")) die_nomem();
+  if (!stralloc_cats(&rcptto,addr.s)) die_nomem();
+  if (!stralloc_0(&rcptto)) die_nomem();
+  out("250 ok\r\n");
+}
+
+
+int saferead(fd,buf,len) int fd; char *buf; int len;
+{
+  int r;
+  flush();
+  r = timeoutread(timeout,fd,buf,len);
+  if (r == -1) if (errno == error_timeout) die_alarm();
+  if (r <= 0) die_read();
+  return r;
+}
+
+char ssinbuf[1024];
+substdio ssin = SUBSTDIO_FDBUF(saferead,0,ssinbuf,sizeof ssinbuf);
+
+struct qmail qqt;
+unsigned int bytestooverflow = 0;
+
+void put(ch)
+char *ch;
+{
+  if (bytestooverflow)
+    if (!--bytestooverflow)
+      qmail_fail(&qqt);
+  qmail_put(&qqt,ch,1);
+}
+
+void blast(hops)
+int *hops;
+{
+  char ch;
+  int state;
+  int flaginheader;
+  int pos; /* number of bytes since most recent \n, if fih */
+  int flagmaybex; /* 1 if this line might match RECEIVED, if fih */
+  int flagmaybey; /* 1 if this line might match \r\n, if fih */
+  int flagmaybez; /* 1 if this line might match DELIVERED, if fih */
+ 
+  state = 1;
+  *hops = 0;
+  flaginheader = 1;
+  pos = 0; flagmaybex = flagmaybey = flagmaybez = 1;
+  for (;;) {
+    substdio_get(&ssin,&ch,1);
+    if (flaginheader) {
+      if (pos < 9) {
+        if (ch != "delivered"[pos]) if (ch != "DELIVERED"[pos]) flagmaybez = 0;
+        if (flagmaybez) if (pos == 8) ++*hops;
+        if (pos < 8)
+          if (ch != "received"[pos]) if (ch != "RECEIVED"[pos]) flagmaybex = 0;
+        if (flagmaybex) if (pos == 7) ++*hops;
+        if (pos < 2) if (ch != "\r\n"[pos]) flagmaybey = 0;
+        if (flagmaybey) if (pos == 1) flaginheader = 0;
+      }
+      ++pos;
+      if (ch == '\n') { pos = 0; flagmaybex = flagmaybey = flagmaybez = 1; }
+    }
+    switch(state) {
+      case 0:
+        if (ch == '\n') straynewline();
+        if (ch == '\r') { state = 4; continue; }
+        break;
+      case 1: /* \r\n */
+        if (ch == '\n') straynewline();
+        if (ch == '.') { state = 2; continue; }
+        if (ch == '\r') { state = 4; continue; }
+        state = 0;
+        break;
+      case 2: /* \r\n + . */
+        if (ch == '\n') straynewline();
+        if (ch == '\r') { state = 3; continue; }
+        state = 0;
+        break;
+      case 3: /* \r\n + .\r */
+        if (ch == '\n') return;
+        put(".");
+        put("\r");
+        if (ch == '\r') { state = 4; continue; }
+        state = 0;
+        break;
+      case 4: /* + \r */
+        if (ch == '\n') { state = 1; break; }
+        if (ch != '\r') { put("\r"); state = 0; }
+    }
+    put(&ch);
+  }
+}
+
+char accept_buf[FMT_ULONG];
+void acceptmessage(qp) unsigned long qp;
+{
+  datetime_sec when;
+  when = now();
+  out("250 ok ");
+  accept_buf[fmt_ulong(accept_buf,(unsigned long) when)] = 0;
+  out(accept_buf);
+  out(" qp ");
+  accept_buf[fmt_ulong(accept_buf,qp)] = 0;
+  out(accept_buf);
+  out("\r\n");
+}
+
+void smtp_data() {
+  int hops;
+  unsigned long qp;
+  char *qqx;
+ 
+  if (!seenmail) { err_wantmail(); return; }
+  if (!rcptto.len) { err_wantrcpt(); return; }
+  seenmail = 0;
+  if (databytes) bytestooverflow = databytes + 1;
+  if (qmail_open(&qqt) == -1) { err_qqt(); return; }
+  qp = qmail_qp(&qqt);
+  out("354 go ahead\r\n");
+ 
+  received(&qqt,"SMTP",local,remoteip,remotehost,remoteinfo,fakehelo);
+  blast(&hops);
+  hops = (hops >= MAXHOPS);
+  if (hops) qmail_fail(&qqt);
+  qmail_from(&qqt,mailfrom.s);
+  qmail_put(&qqt,rcptto.s,rcptto.len);
+ 
+  qqx = qmail_close(&qqt);
+  if (!*qqx) { acceptmessage(qp); return; }
+  if (hops) { out("554 too many hops, this message is looping (#5.4.6)\r\n"); return; }
+  if (databytes) if (!bytestooverflow) { out("552 sorry, that message size exceeds my databytes limit (#5.3.4)\r\n"); return; }
+  if (*qqx == 'D') out("554 "); else out("451 ");
+  out(qqx + 1);
+  out("\r\n");
+}
+
+struct commands smtpcommands[] = {
+  { "rcpt", smtp_rcpt, 0 }
+, { "mail", smtp_mail, 0 }
+, { "data", smtp_data, flush }
+, { "quit", smtp_quit, flush }
+, { "helo", smtp_helo, flush }
+, { "ehlo", smtp_ehlo, flush }
+, { "rset", smtp_rset, 0 }
+, { "help", smtp_help, flush }
+, { "noop", err_noop, flush }
+, { "vrfy", err_vrfy, flush }
+, { 0, err_unimpl, flush }
+} ;
+
+void main()
+{
+  sig_pipeignore();
+  if (chdir(auto_qmail) == -1) die_control();
+  setup();
+  if (ipme_init() != 1) die_ipme();
+  smtp_greet("220 ");
+  out(" ESMTP\r\n");
+  if (commands(&ssin,&smtpcommands) == 0) die_read();
+  die_nomem();
+}