#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();

}