#include <unistd.h>

#include "buffer.h"
#include "byte.h"
#include "case.h"
#include "env.h"
#include "exit.h"
#include "fmt.h"
#include "ip.h"
#include "scan.h"
#include "sig.h"
#include "str.h"
#include "stralloc.h"

#include "auto_qmail.h"
#include "control.h"
#include "now.h"
#include "qmail.h"
#include "rcpthosts.h"
#include "received.h"

#define PORT_QMTP  "209"
#define PORT_QMTPS "6209"

/** @file qmail-qmtpd.c -- QMTP/QMTPS server
    @brief requires sslserver */

void badproto()
{
  _exit(100);
}

void resources()
{
  _exit(111);
}

ssize_t safewrite(int fd, char *buf, int len)
{
  int r;
  r = write(fd, buf, len);
  if (r <= 0) _exit(0);
  return r;
}

char outbuf[256];
buffer bo = BUFFER_INIT(safewrite, 1, outbuf, sizeof(outbuf));

ssize_t saferead(int fd, char *buf, int len)
{
  int r;
  buffer_flush(&bo);
  r = read(fd, buf, len);
  if (r <= 0) _exit(0);
  return r;
}

char inbuf[512];
buffer bi = BUFFER_INIT(saferead, 0, inbuf, sizeof(inbuf));

unsigned long getlen()
{
  unsigned long len = 0;
  char ch;
  for (;;) {
    buffer_get(&bi, &ch, 1);
    if (ch == ':') return len;
    if (ch < '0' || ch > '9') resources();
    if (len > 200000000) resources();
    len = 10 * len + (ch - '0');
  }
}

void getcomma()
{
  char ch;
  buffer_get(&bi, &ch, 1);
  if (ch != ',') badproto();
}

unsigned long databytes = 0;
unsigned int bytestooverflow = 0;
struct qmail qq;

char buf[1000];
char buf2[100];

char *remotehost;
char *remoteinfo;
char *remoteip;
char *localport;
char *local;

stralloc failure = {0};
stralloc protocol = {0};
stralloc tlsinfo = {0};

char *relayclient;
int relayclientlen = 0;

char *ucspitls;
char *tlsversion;
char *cipher;
char *cipherperm;
char *cipherused;
char *clientdn;
char *clientcn;
char *dnemail;

int seentls = 0;

int modssl_info()
{
  tlsversion = env_get("SSL_PROTOCOL");
  if (!tlsversion) return 0;
  seentls = 1;

  cipher = env_get("SSL_CIPHER");
  if (!cipher) cipher = "unknown";
  cipherperm = env_get("SSL_CIPHER_ALGKEYSIZE");
  if (!cipherperm) cipherperm = "unknown";
  cipherused = env_get("SSL_CIPHER_USEKEYSIZE");
  if (!cipherused) cipherused = "unknown";
  clientdn = env_get("SSL_CLIENT_S_DN");
  if (clientdn)
    seentls = 2;
  else
    clientdn = "none";

  if (!stralloc_copys(&tlsinfo, tlsversion)) resources();
  if (!stralloc_cats(&tlsinfo, ": ")) resources();
  if (!stralloc_cats(&tlsinfo, cipher)) resources();
  if (!stralloc_cats(&tlsinfo, " [")) resources();
  if (!stralloc_cats(&tlsinfo, cipherused)) resources();
  if (!stralloc_cats(&tlsinfo, "/")) resources();
  if (!stralloc_cats(&tlsinfo, cipherperm)) resources();
  if (!stralloc_cats(&tlsinfo, "] \n")) resources();
  if (!stralloc_cats(&tlsinfo, "  DN=")) resources();
  if (!stralloc_cats(&tlsinfo, clientdn)) resources();
  if (!stralloc_0(&tlsinfo)) resources();

  if (!stralloc_append(&protocol, "S")) resources();

  if (seentls == 2) {
    clientcn = env_get("SSL_CLIENT_S_DN_CN");
    remoteinfo = clientcn ? clientcn : clientdn;
    dnemail = env_get("SSL_CLIENT_S_DN_Email");
    if (!dnemail) dnemail = "unknown";
    if (!stralloc_append(&protocol, "A")) resources();
    relayclient = "";
  }
  return 1;
}

int main()
{
  char ch;
  int i;
  unsigned long biglen;
  unsigned long len;
  int flagdos;
  int flagsenderok;
  int flagbother;
  unsigned long qp;
  char *result;
  char *x;
  unsigned long u;

  sig_pipeignore();
  sig_alarmcatch(resources);
  alarm(3600);

  if (chdir(auto_qmail) == -1) resources();

  if (control_init() == -1) resources();
  if (rcpthosts_init() == -1) resources();

  if (control_readint(&databytes, "control/databytes") == -1) resources();
  x = env_get("DATABYTES");
  if (x) {
    scan_ulong(x, &u);
    databytes = u;
  }
  if (!(databytes + 1)) --databytes;

  relayclient = env_get("RELAYCLIENT");
  remotehost = env_get("TCP6REMOTEHOST");
  if (!remotehost) remotehost = env_get("TCPREMOTEHOST");
  if (!remotehost) remotehost = "unknown";
  remoteinfo = env_get("TCP6REMOTEINFO");
  if (!remoteinfo) remoteinfo = env_get("TCPREMOTEINFO");
  remoteip = env_get("TCP6REMOTEIP");
  if (!remoteip) remoteip = env_get("TCPREMOTEIP");
  if (remoteip && byte_equal(remoteip, 7, V4MAPPREFIX)) remoteip = remoteip + 7;
  if (!remoteip) remoteip = "unknown";
  local = env_get("TCP6LOCALHOST");
  if (!local) local = env_get("TCPLOCALHOST");
  if (!local) local = env_get("TCP6LOCALIP");
  if (!local) local = env_get("TCPLOCALIP");
  if (!local) local = "unknown";
  localport = env_get("TCP6LOCALPORT");
  if (!localport) localport = env_get("TCPLOCALPORT");
  if (!localport) localport = "0";

  if (!stralloc_copys(&protocol, "QMTP")) resources();
  if (!case_diffs(localport, PORT_QMTPS))
    if (!modssl_info()) resources();

  if (relayclient) relayclientlen = str_len(relayclient);

  for (;;) {
    if (!stralloc_copys(&failure, "")) resources();
    flagsenderok = 1;

    len = getlen();
    if (len == 0) badproto();

    if (databytes) bytestooverflow = databytes + 1;
    if (qmail_open(&qq) == -1) resources();
    qp = qmail_qp(&qq);

    buffer_get(&bi, &ch, 1);
    --len;
    if (ch == 10)
      flagdos = 0;
    else if (ch == 13)
      flagdos = 1;
    else
      badproto();

    /* no fakehelo, no spfinfo */

    received(&qq, protocol.s, local, remoteip, remotehost, remoteinfo, (char *)0, tlsinfo.s, (char *)0);

    /* XXX: check for loops? only if len is big? */

    if (flagdos) {
      while (len > 0) {
        buffer_get(&bi, &ch, 1);
        --len;
        while ((ch == 13) && len) {
          buffer_get(&bi, &ch, 1);
          --len;
          if (ch == 10) break;
          if (bytestooverflow)
            if (!--bytestooverflow) qmail_fail(&qq);
          qmail_put(&qq, "\015", 1);
        }
        if (bytestooverflow)
          if (!--bytestooverflow) qmail_fail(&qq);
        qmail_put(&qq, &ch, 1);
      }
    } else {
      if (databytes && len > databytes) {
        bytestooverflow = 0;
        qmail_fail(&qq);
      }
      while (len > 0) { /* XXX: could speed this up, obviously */
        buffer_get(&bi, &ch, 1);
        --len;
        qmail_put(&qq, &ch, 1);
      }
    }
    getcomma();

    len = getlen();

    if (len >= 1000) {
      buf[0] = 0;
      flagsenderok = 0;
      for (i = 0; i < len; ++i) buffer_get(&bi, &ch, 1);
    } else {
      for (i = 0; i < len; ++i) {
        buffer_get(&bi, buf + i, 1);
        if (!buf[i]) flagsenderok = 0;
      }
      buf[len] = 0;
    }
    getcomma();

    flagbother = 0;
    qmail_from(&qq, buf);
    if (!flagsenderok) qmail_fail(&qq);

    biglen = getlen();
    while (biglen > 0) {
      if (!stralloc_append(&failure, "")) resources();

      len = 0;
      for (;;) {
        if (!biglen) badproto();
        buffer_get(&bi, &ch, 1);
        --biglen;
        if (ch == ':') break;
        if (ch < '0' || ch > '9') resources();
        if (len > 200000000) resources();
        len = 10 * len + (ch - '0');
      }
      if (len >= biglen) badproto();
      if (len + relayclientlen >= 1000) {
        failure.s[failure.len - 1] = 'L';
        for (i = 0; i < len; ++i) buffer_get(&bi, &ch, 1);
      } else {
        for (i = 0; i < len; ++i) {
          buffer_get(&bi, buf + i, 1);
          if (!buf[i]) failure.s[failure.len - 1] = 'N';
        }
        buf[len] = 0;

        if (relayclientlen) str_copy(buf + len, relayclient);
        if (!relayclient) switch (rcpthosts(buf, len))
          {
            case -1: resources();
            case 0:  failure.s[failure.len - 1] = 'D';
          }

        if (!failure.s[failure.len - 1]) {
          qmail_to(&qq, buf);
          flagbother = 1;
        }
      }
      getcomma();
      biglen -= (len + 1);
    }
    getcomma();

    if (!flagbother) qmail_fail(&qq);
    result = qmail_close(&qq);
    if (!flagsenderok) result = "D Unacceptable sender (#5.1.7)";
    if (databytes)
      if (!bytestooverflow) result = "D Sorry, that message size exceeds my databytes limit (#5.3.4)";

    if (*result) {
      len = str_len(result);
    } else {
      /* success! */
      len = 0;
      len += fmt_str(buf2 + len, "K Ok ");
      len += fmt_ulong(buf2 + len, (unsigned long)now());
      len += fmt_str(buf2 + len, " qp ");
      len += fmt_ulong(buf2 + len, qp);
      buf2[len] = 0;
      result = buf2;
    }

    len = fmt_ulong(buf, len);
    buf[len++] = ':';
    len += fmt_str(buf + len, result);
    buf[len++] = ',';

    for (i = 0; i < failure.len; ++i) {
      switch (failure.s[i]) {
        case 0: buffer_put(&bo, buf, len); break;
        case 'D':
          buffer_puts(&bo, "66:D Sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1),");
          break;
        default: buffer_puts(&bo, "46:D Sorry, I can't handle that recipient (#5.1.3),"); break;
      }
    }

    /* bo will be flushed when we read from the network again */
  }
}