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/* ISC license. */
#include <string.h>
#include <strings.h>
#include <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <skalibs/types.h>
#include <skalibs/exec.h>
#include <skalibs/fmtscan.h>
#include <skalibs/buffer.h>
#include <skalibs/cdb.h>
#include <skalibs/stralloc.h>
#include <skalibs/sig.h>
#include <skalibs/tai.h>
#include <skalibs/djbunix.h>
#include <skalibs/socket.h>
#include <skalibs/ip46.h>
#include <skalibs/unix-timed.h>
#include <skalibs/lolstdio.h>
#include <smtpd-starttls-proxy/config.h>
#include "qmailr.h"
#include "qmail-remote.h"
#define dieusage() qmailr_perm("qmail-remote was invoked improperly")
static inline void exec_notls (int fd, char const *fmtip, unsigned int timeoutremote, size_t const *eaddrpos, unsigned int n, char const *storage) gccattr_noreturn ;
static inline void exec_notls (int fd, char const *fmtip, unsigned int timeoutremote, size_t const *eaddrpos, unsigned int n, char const *storage)
{
unsigned int m = 0 ;
char fmtfd[UINT_FMT] ;
char fmtt[UINT_FMT] ;
char const *argv[10 + n] ;
fmtfd[uint_fmt(fmtfd, (unsigned int)fd)] = 0 ;
fmtt[uint_fmt(fmtt, timeoutremote)] = 0 ;
argv[m++] = SMTPD_STARTTLS_PROXY_LIBEXECPREFIX "qmail-remote-io" ;
argv[m++] = "-t" ;
argv[m++] = fmtt ;
argv[m++] = "-6" ;
argv[m++] = fmtfd ;
argv[m++] = "-7" ;
argv[m++] = fmtfd ;
argv[m++] = "--" ;
argv[m++] = fmtip ;
for (unsigned int i = 0 ; i < n ; i++) argv[m++] = storage + eaddrpos[i] ;
argv[m++] = 0 ;
exec(argv) ;
qmailr_tempusys("exec ", argv[0]) ;
}
static int smtp_start (buffer *in, buffer *out, char const *helohost, unsigned int timeout, char const *fmtip)
{
int hastls = 0 ;
tain deadline ;
char line[1024] ;
int r = qmailr_smtp_read_answer(in, line, 1024, timeout) ;
if (r == -1) qmailr_tempusys("read from ", fmtip) ;
if (!r) qmailr_temp("Connected to ", fmtip, " but connection died") ;
if (r != 220)
{
qmailr_smtp_quit(out, timeout) ;
qmailr_temp("Connected to ", fmtip, " but greeting failed") ;
}
buffer_putnoflush(out, "EHLO ", 5) ;
buffer_putsnoflush(out, helohost) ;
buffer_putnoflush(out, "\r\n", 2) ;
tain_addsec_g(&deadline, timeout) ;
if (!buffer_timed_flush_g(out, &deadline))
qmailr_tempusys("send ", "EHLO", " to ", fmtip) ;
tain_addsec_g(&deadline, timeout) ;
for (;;)
{
unsigned int code = 250 ;
int r = qmailr_smtp_read_line(in, line, 1024, &code, &deadline) ;
if (r == -1) qmailr_tempusys("read from ", fmtip) ;
if (!r) qmailr_temp("Connected to ", fmtip, " but connection died") ;
if (code != 250) qmailr_temp("Connected to ", fmtip, " but it speaks a weird protocol") ;
if (!strcasecmp(line + 4, "STARTTLS")) hastls = 1 ;
if (r == 1) break ;
}
return hastls ;
}
static void attempt_smtp (int fd, char const *ip, int is6, unsigned int timeoutconnect, unsigned int timeoutremote, qmailr_tls const *qtls, size_t helopos, size_t const *eaddrpos, unsigned int n, size_t mxnamepos, char const *storage)
{
int hastls ;
char inbuf[2048] ;
char outbuf[2048] ;
char fmtip[IP6_FMT] ;
buffer in = BUFFER_INIT(&buffer_read, fd, inbuf, 2048) ;
buffer out = BUFFER_INIT(&buffer_write, fd, outbuf, 2048) ;
if (is6) fmtip[ip6_fmt(fmtip, ip)] = 0 ;
else fmtip[ip4_fmt(fmtip, ip)] = 0 ;
hastls = smtp_start(&in, &out, storage + helopos, timeoutremote, fmtip) ;
if (qtls->flagwanttls)
{
if (hastls)
{
int r ;
tain deadline ;
char line[1024] ;
buffer_putsnoflush(&out, "STARTTLS\r\n") ;
tain_addsec_g(&deadline, timeoutremote) ;
if (!buffer_timed_flush_g(&out, &deadline)) qmailr_tempusys("send ", "STARTTLS", " to ", fmtip) ;
r = qmailr_smtp_read_answer(&in, line, 1024, timeoutremote) ;
if (r == -1) qmailr_tempusys("read from ", fmtip) ;
else if (!r)
{
qmailr_smtp_quit(&out, timeoutremote) ;
qmailr_temp("Connected to ", fmtip, " but connection died") ;
}
else if (r == 220) run_tls(fd, fmtip, timeoutconnect, timeoutremote, qtls, eaddrpos, n, mxnamepos, storage) ;
if (qtls->strictness) return ;
}
else if (qtls->strictness >= 2) return ;
}
exec_notls(fd, fmtip, timeoutremote, eaddrpos, n, storage) ;
}
int main (int argc, char const *const *argv)
{
stralloc storage = STRALLOC_ZERO ;
stralloc ipme4 = STRALLOC_ZERO ;
stralloc ipme6 = STRALLOC_ZERO ;
qmailr_tls qtls = QMAILR_TLS_ZERO ;
smtproutes routes = SMTPROUTES_ZERO ;
unsigned int timeoutconnect = 60, timeoutremote = 1200, timeoutdns = 0 ;
char const *host ;
size_t mepos, helopos, hostpos = 0 ;
uint16_t port = 25 ;
int r ;
if (argc-- < 4) dieusage() ;
argv++ ;
if (chdir(SMTPD_STARTTLS_PROXY_QMAIL_HOME) == -1) qmailr_tempusys("chdir to ", SMTPD_STARTTLS_PROXY_QMAIL_HOME) ;
if (sig_altignore(SIGPIPE) == -1) qmailr_tempusys("ignore SIGPIPE") ;
host = *argv++ ; argc-- ;
tain_now_set_stopwatch_g() ;
/* init control */
r = qmailr_control_read("control/me", &storage, &mepos) ;
if (r == -1) qmailr_tempusys("read ", "control/me") ;
else if (!r) qmailr_temp("Invalid ", "control/me") ;
r = qmailr_control_read("control/helohost", &storage, &helopos) ;
if (r == -1) qmailr_tempusys("read ", "control/helohost") ;
else if (!r) helopos = mepos ;
r = qmailr_control_readint("control/timeoutconnect", &timeoutconnect, &storage) ;
if (r == -1) qmailr_tempusys("read ", "control/timeoutconnect") ;
r = qmailr_control_readint("control/timeoutremote", &timeoutremote, &storage) ;
if (r == -1) qmailr_tempusys("read ", "control/timeoutremote") ;
r = qmailr_control_readint("control/timeoutdns", &timeoutdns, &storage) ;
if (r == -1) qmailr_tempusys("read ", "control/timeoutdns") ;
if (!qmailr_control_readiplist("control/ipme", &ipme4, &ipme6))
qmailr_tempusys("read ", "control/ipme") ;
qsort(ipme4.s, ipme4.len >> 2, 4, &qmailr_memcmp4) ;
qsort(ipme6.s, ipme6.len >> 4, 16, &qmailr_memcmp16) ;
if (!qmailr_tls_init(&qtls, &storage))
qmailr_tempusys("read ", "TLS control files") ;
if (smtproutes_init(&routes))
{
if (!smtproutes_match(&routes, host, &storage, &hostpos, &port))
{
size_t hostlen = strlen(host) ;
for (size_t i = 0 ; i < hostlen ; i++) if (host[i] == '.')
if (smtproutes_match(&routes, host + i + 1, &storage, &hostpos, &port)) break ;
if (!hostpos) smtproutes_match(&routes, "", &storage, &hostpos, &port) ;
}
smtproutes_free(&routes) ;
}
{
genalloc mxipind = GENALLOC_ZERO ;
mxip const *mxs ;
size_t eaddrpos[argc] ;
size_t ntot = 0 ;
unsigned int pass = 1 + (qtls.flagwanttls && qtls.strictness == 1) ;
unsigned int mxn = dns_stuff(hostpos ? storage.s + hostpos : host, argv, argc, eaddrpos, &mxipind, &storage, timeoutdns, ipme4.s, ipme4.len >> 2, ipme6.s, ipme6.len >> 4, !hostpos) ;
if (!mxn) qmailr_perm("No suitable MX found for remote host") ;
stralloc_free(&ipme4) ;
stralloc_free(&ipme6) ;
mxs = genalloc_s(mxip, &mxipind) ;
for (unsigned int i = 0 ; i < mxn ; i++) ntot += mxs[i].n4 + mxs[i].n6 ;
if (!ntot) qmailr_perm("No suitable IP addresses for the MX") ;
while (pass--)
{
if (!pass && qtls.strictness == 1) qtls.flagwanttls = 0 ;
for (unsigned int i = 0 ; i < mxn ; i++)
{
#ifdef SKALIBS_IPV6_ENABLED
for (unsigned int j = 0 ; j < mxs[i].n6 ; j++)
{
char const *ip = storage.s + mxs[i].pos6 + (j << 4) ;
tain deadline ;
int fd ;
if (qmailr_tcpto_match(ip, 1)) continue ;
fd = socket_tcp6() ;
if (fd == -1) qmailr_tempusys("create socket") ;
tain_addsec_g(&deadline, timeoutconnect) ;
if (!socket_deadlineconnstamp6_g(fd, ip, port, &deadline))
{
if (!qmailr_tcpto_update(ip, 1, errno == ETIMEDOUT))
qmailr_tempusys("update ", "tcpto6") ;
fd_close(fd) ;
continue ;
}
if (!qmailr_tcpto_update(ip, 1, 0))
qmailr_tempusys("update ", "tcpto6") ;
attempt_smtp(fd, ip, 1, timeoutconnect, timeoutremote, &qtls, helopos, eaddrpos, argc, mxs[i].namepos, storage.s) ;
fd_close(fd) ;
}
#endif
for (unsigned int j = 0 ; j < mxs[i].n4 ; j++)
{
char const *ip = storage.s + mxs[i].pos4 + (j << 2) ;
tain deadline ;
int fd ;
if (qmailr_tcpto_match(ip, 0)) continue ;
fd = socket_tcp4() ;
if (fd == -1) qmailr_tempusys("create socket") ;
tain_addsec_g(&deadline, timeoutconnect) ;
if (!socket_deadlineconnstamp4_g(fd, ip, port, &deadline))
{
if (!qmailr_tcpto_update(ip, 0, errno == ETIMEDOUT))
qmailr_tempusys("update ", "tcpto") ;
fd_close(fd) ;
continue ;
}
if (!qmailr_tcpto_update(ip, 0, 0))
qmailr_tempusys("update ", "tcpto") ;
attempt_smtp(fd, ip, 0, timeoutconnect, timeoutremote, &qtls, helopos, eaddrpos, argc, mxs[i].namepos, storage.s) ;
fd_close(fd) ;
}
}
}
}
qmailr_tempusys("establish an SMTP connection") ;
_exit(101) ; /* not reached */
}
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