static void start_connect(SESSION *session)
{
int fd;
struct linger linger;
/*
* Some systems don't set the socket error when connect() fails early
* (loopback) so we must deal with the error immediately, rather than
* retrieving it later with getsockopt(). We can't use MSG_PEEK to
* distinguish between server disconnect and connection refused.
*/
if ((fd = socket(sa->sa_family, SOCK_STREAM, 0)) < 0)
msg_fatal("socket: %m");
(void) non_blocking(fd, NON_BLOCKING);
linger.l_onoff = 1;
linger.l_linger = 0;
if (setsockopt(fd, SOL_SOCKET, SO_LINGER, (char *) &linger,
sizeof(linger)) < 0)
msg_warn("setsockopt SO_LINGER %d: %m", linger.l_linger);
session->stream = vstream_fdopen(fd, O_RDWR);
event_enable_write(fd, connect_done, (char *) session);
smtp_timeout_setup(session->stream, var_timeout);
if (inet_windowsize > 0)
set_inet_windowsize(fd, inet_windowsize);
if (sane_connect(fd, sa, sa_length) < 0 && errno != EINPROGRESS)
fail_connect(session);
}
static int smtpd_proxy_connect(SMTPD_STATE *state)
{
SMTPD_PROXY *proxy = state->proxy;
int fd;
char *lines;
char *words;
VSTRING *buf;
int bad;
char *word;
static const NAME_CODE known_xforward_features[] = {
XFORWARD_NAME, SMTPD_PROXY_XFORWARD_NAME,
XFORWARD_ADDR, SMTPD_PROXY_XFORWARD_ADDR,
XFORWARD_PORT, SMTPD_PROXY_XFORWARD_PORT,
XFORWARD_PROTO, SMTPD_PROXY_XFORWARD_PROTO,
XFORWARD_HELO, SMTPD_PROXY_XFORWARD_HELO,
XFORWARD_IDENT, SMTPD_PROXY_XFORWARD_IDENT,
XFORWARD_DOMAIN, SMTPD_PROXY_XFORWARD_DOMAIN,
0, 0,
};
int server_xforward_features;
int (*connect_fn) (const char *, int, int);
const char *endpoint;
/*
* Find connection method (default inet)
*/
if (strncasecmp("unix:", proxy->service_name, 5) == 0) {
endpoint = proxy->service_name + 5;
connect_fn = unix_connect;
} else {
if (strncasecmp("inet:", proxy->service_name, 5) == 0)
endpoint = proxy->service_name + 5;
else
endpoint = proxy->service_name;
connect_fn = inet_connect;
}
/*
* Connect to proxy.
*/
if ((fd = connect_fn(endpoint, BLOCKING, proxy->timeout)) < 0) {
msg_warn("connect to proxy filter %s: %m", proxy->service_name);
return (smtpd_proxy_rdwr_error(state, 0));
}
proxy->service_stream = vstream_fdopen(fd, O_RDWR);
/* Needed by our DATA-phase record emulation routines. */
vstream_control(proxy->service_stream, VSTREAM_CTL_CONTEXT,
(char *) state, VSTREAM_CTL_END);
/* Avoid poor performance when TCP MSS > VSTREAM_BUFSIZE. */
if (connect_fn == inet_connect)
vstream_tweak_tcp(proxy->service_stream);
smtp_timeout_setup(proxy->service_stream, proxy->timeout);
/*
* Get server greeting banner.
*
* If this fails then we have a problem because the proxy should always
* accept our connection. Make up our own response instead of passing
* back a negative greeting banner: the proxy open is delayed to the
* point that the client expects a MAIL FROM or RCPT TO reply.
*/
if (smtpd_proxy_cmd(state, SMTPD_PROX_WANT_OK, SMTPD_PROXY_CONN_FMT)) {
smtpd_proxy_fake_server_reply(state, CLEANUP_STAT_PROXY);
smtpd_proxy_close(state);
return (-1);
}
/*
* Send our own EHLO command. If this fails then we have a problem
* because the proxy should always accept our EHLO command. Make up our
* own response instead of passing back a negative EHLO reply: the proxy
* open is delayed to the point that the remote SMTP client expects a
* MAIL FROM or RCPT TO reply.
*/
if (smtpd_proxy_cmd(state, SMTPD_PROX_WANT_OK, "EHLO %s",
proxy->ehlo_name)) {
smtpd_proxy_fake_server_reply(state, CLEANUP_STAT_PROXY);
smtpd_proxy_close(state);
return (-1);
}
/*
* Parse the EHLO reply and see if we can forward logging information.
*/
server_xforward_features = 0;
lines = STR(proxy->reply);
while ((words = mystrtok(&lines, "\n")) != 0) {
if (mystrtok(&words, "- ") && (word = mystrtok(&words, " \t")) != 0) {
if (strcasecmp(word, XFORWARD_CMD) == 0)
while ((word = mystrtok(&words, " \t")) != 0)
server_xforward_features |=
name_code(known_xforward_features,
NAME_CODE_FLAG_NONE, word);
}
}
/*
* Send XFORWARD attributes. For robustness, explicitly specify what SMTP
* session attributes are known and unknown. Make up our own response
* instead of passing back a negative XFORWARD reply: the proxy open is
* delayed to the point that the remote SMTP client expects a MAIL FROM
* or RCPT TO reply.
*/
if (server_xforward_features) {
buf = vstring_alloc(100);
bad =
(((server_xforward_features & SMTPD_PROXY_XFORWARD_NAME)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_NAME,
IS_AVAIL_CLIENT_NAME(FORWARD_NAME(state)),
FORWARD_NAME(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_ADDR)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_ADDR,
IS_AVAIL_CLIENT_ADDR(FORWARD_ADDR(state)),
FORWARD_ADDR(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_PORT)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_PORT,
IS_AVAIL_CLIENT_PORT(FORWARD_PORT(state)),
FORWARD_PORT(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_HELO)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_HELO,
IS_AVAIL_CLIENT_HELO(FORWARD_HELO(state)),
FORWARD_HELO(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_IDENT)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_IDENT,
IS_AVAIL_CLIENT_IDENT(FORWARD_IDENT(state)),
FORWARD_IDENT(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_PROTO)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_PROTO,
IS_AVAIL_CLIENT_PROTO(FORWARD_PROTO(state)),
FORWARD_PROTO(state)))
|| ((server_xforward_features & SMTPD_PROXY_XFORWARD_DOMAIN)
&& smtpd_proxy_xforward_send(state, buf, XFORWARD_DOMAIN, 1,
STREQ(FORWARD_DOMAIN(state), MAIL_ATTR_RWR_LOCAL) ?
XFORWARD_DOM_LOCAL : XFORWARD_DOM_REMOTE))
|| smtpd_proxy_xforward_flush(state, buf));
vstring_free(buf);
if (bad) {
smtpd_proxy_fake_server_reply(state, CLEANUP_STAT_PROXY);
smtpd_proxy_close(state);
return (-1);
}
}
/*
* Pass-through the remote SMTP client's MAIL FROM command. If this
* fails, then we have a problem because the proxy should always accept
* any MAIL FROM command that was accepted by us.
*/
if (smtpd_proxy_cmd(state, SMTPD_PROX_WANT_OK, "%s",
proxy->mail_from) != 0) {
/* NOT: smtpd_proxy_fake_server_reply(state, CLEANUP_STAT_PROXY); */
smtpd_proxy_close(state);
return (-1);
}
return (0);
}
