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/* ISC license. */
#include <skalibs/bsdsnowflake.h>
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <skalibs/stat.h>
#include <skalibs/posixplz.h>
#include <skalibs/uint16.h>
#include <skalibs/buffer.h>
#include <skalibs/cdb.h>
#include <skalibs/cdbmake.h>
#include <skalibs/stralloc.h>
#include <skalibs/djbtime.h>
#include <skalibs/djbunix.h>
#include <skalibs/lolstdio.h>
#include <smtpd-starttls-proxy/config.h>
#include "qmailr.h"
#include "qmail-remote.h"
/*
qmail-remote uses a "constmap" for smtproutes, which is
basically a cdb in RAM. Every instance of qmail-remote
parses control/smtproutes to make the constmap.
We replace it with a real cdb, stored in the filesystem.
It saves CPU (N-1 instances of qmail-remote use the cdb
directly) and RAM (the cdb is read-only and shared).
The cdb is updated whenever control/smtproutes is newer.
We have to lock around the test to avoid several
concurrent compilations; the current lock feels too big,
the crit section can probably be made smaller, but the
behaviour is safe and avoids retry heuristics.
*/
/*
Key to the control/smtproutes parser
[host]:[relay[:port]]
An ip in square brackets is acceptable in host and relay, even ipv6
0 1 2 3 4 5 6 7 8 9
st\ev EOF # \n : [ ] 0-9 a-f other special
0 h n n n
START END COMMENT START RELAY QHOST X HOST HOST HOST X
1
COMMENT END COMMENT START COMMENT COMMENT COMMENT COMMENT COMMENT COMMENT COMMENT
2 n n n
QHOST X X X QHOST X EHOST QHOST QHOST X X
3 n h n n n
HOST X HOST X RELAY X X HOST HOST HOST X
4 h
EHOST X X X RELAY X X X X X X
5 ra n ra r n n n
RELAY END INRELAY START PORT QRELAY X INRELAY INRELAY INRELAY X
6 n n n
QRELAY X X X QRELAY X ERELAY QRELAY QRELAY X X
7 ra ra r n n n
INRELAY END X START PORT X X INRELAY INRELAY INRELAY X
8 ra ra r
ERELAY END X START PORT X X X X X X
9 pa pa n
PORT END X START X X X PORT X X X
END=a, X=b
0x0100 n push character
0x0200 h compute host length
0x0400 r compute relay length
0x0800 p compute port
0x1000 a add route entry
*/
static inline uint8_t cclass (char c)
{
static uint8_t const table[128] = "0999999999299999999999999999999998918889999898786666666666399898877777788888888888888888884958898888888888888888888888888899999" ;
return c & 0x80 ? 9 : table[(uint8_t)c] - '0' ;
}
static inline char getnext (buffer *b)
{
char c ;
ssize_t r = buffer_get(b, &c, 1) ;
if (r == -1) qmailr_tempusys("read ", "control/smtproutes") ;
return r ? c : 0 ;
}
static inline void smtproutes_compile (int fdr, int fdw)
{
static uint16_t const table[10][10] =
{
{ 0x000a, 0x0001, 0x0000, 0x0205, 0x0002, 0x000b, 0x0103, 0x0103, 0x0103, 0x000b },
{ 0x000a, 0x0001, 0x0000, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001 },
{ 0x000b, 0x000b, 0x000b, 0x0102, 0x000b, 0x0004, 0x0102, 0x0102, 0x0102, 0x000b },
{ 0x000b, 0x0103, 0x000b, 0x0205, 0x000b, 0x000b, 0x0103, 0x0103, 0x0103, 0x000b },
{ 0x000b, 0x000b, 0x000b, 0x0205, 0x000b, 0x000b, 0x000b, 0x000b, 0x000b, 0x000b },
{ 0x140a, 0x0107, 0x1400, 0x0409, 0x0006, 0x000b, 0x0107, 0x0107, 0x0107, 0x000b },
{ 0x000b, 0x000b, 0x000b, 0x0106, 0x000b, 0x0008, 0x0106, 0x0106, 0x0106, 0x000b },
{ 0x140a, 0x000b, 0x1400, 0x0409, 0x000b, 0x000b, 0x0107, 0x0107, 0x0107, 0x000b },
{ 0x140a, 0x000b, 0x1400, 0x0409, 0x000b, 0x000b, 0x000b, 0x000b, 0x000b, 0x000b },
{ 0x180a, 0x000b, 0x1800, 0x000b, 0x000b, 0x000b, 0x0109, 0x000b, 0x000b, 0x000b }
} ;
cdbmaker cm = CDBMAKER_ZERO ;
stralloc sa = STRALLOC_ZERO ;
char buf[2048] ;
buffer b = BUFFER_INIT(&buffer_read, fdr, buf, 2048) ;
uint32_t relaypos = 0, relayend = 0 ;
uint8_t state = 0 ;
if (!cdbmake_start(&cm, fdw)) qmailr_tempusys("cdbmake_start") ;
while (state < 0x0a)
{
char c = getnext(&b) ;
uint16_t val = table[state][cclass(c)] ;
LOLDEBUG("state %hhu, char %c, newstate %hu, actions %s%s%s%s%s", state, c, val & 0x000f,
val & 0x0100 ? "n" : "",
val & 0x0200 ? "h" : "",
val & 0x0400 ? "r" : "",
val & 0x0800 ? "p" : "",
val & 0x1000 ? "a" : "") ;
state = val & 0x000f ;
if (val & 0x0100)
{
if (!stralloc_catb(&sa, &c, 1)) dienomem() ;
}
if (val & 0x0200)
{
relaypos = sa.len + 1 ;
if (!stralloc_catb(&sa, "\0\0\31", 3)) dienomem() ;
}
if (val & 0x0400)
{
if (!stralloc_0(&sa)) dienomem() ;
relayend = sa.len ;
}
if (val & 0x0800)
{
uint16_t port ;
if (!stralloc_0(&sa)) dienomem() ;
if (!uint160_scan(sa.s + relayend, &port)) qmailr_temp("Invalid port in ", "control/smtproutes") ;
uint16_pack_big(sa.s + relaypos, port) ;
}
if (val & 0x1000)
{
if (relaypos || relayend > 2 + relaypos)
{
uint16_t port ;
uint16_unpack_big(sa.s + relaypos, &port) ;
LOLDEBUG("adding entry: %.*s -> %.*s port %hu", (int)relaypos, sa.s, (int)(relayend - relaypos - 2), sa.s + relaypos + 2, port) ;
if (!cdbmake_add(&cm, sa.s, relaypos, sa.s + relaypos, relayend - relaypos))
qmailr_tempusys("cdbmake_add") ;
}
sa.len = 0 ;
}
}
if (state != 0x0a) qmailr_temp("Syntax error in ", "control/smtproutes") ;
stralloc_free(&sa) ;
if (!cdbmake_finish(&cm)) qmailr_tempusys("cdbmake_finish") ;
}
int smtproutes_init (smtproutes *routes)
{
static char const *cdbfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/smtproutes.cdb" ;
static char const *lckfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/smtproutes.lock" ;
static char const *txtfile = SMTPD_STARTTLS_PROXY_QMAIL_HOME "/control/smtproutes" ;
static size_t const cdblen = sizeof(SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/smtproutes.cdb") - 1 ;
int fdl = openc_create(lckfile) ;
if (fdl == -1) qmailr_tempusys("open ", "run/qmail-remote/smtproutes.lock") ;
if (fd_lock(fdl, 1, 0) == -1) qmailr_tempusys("lock ", "run/qmail-remote/smtproutes.lock") ;
int fdc = openc_read(cdbfile) ;
if (fdc >= 0)
{
struct stat stc, str ;
if (fstat(fdc, &stc) == -1) qmailr_tempusys("fstat ", "run/qmail-remote/smtproutes.cdb") ;
if (stat(txtfile, &str) == -1)
{
if (errno != ENOENT) qmailr_tempusys("fstat ", "control/smtproutes") ;
unlink_void(cdbfile) ;
fd_close(fdc) ;
goto zero ;
}
if (timespec_cmp(&stc.st_mtim, &str.st_mtim) > 0) goto useit ;
fd_close(fdc) ;
}
int fdr = openc_read(txtfile) ;
if (fdr == -1)
{
if (errno != ENOENT) qmailr_tempusys("open ", "control/smtproutes") ;
goto zero ;
}
{
char tmp[cdblen + 8] ;
memcpy(tmp, cdbfile, cdblen) ;
memcpy(tmp + cdblen, ":XXXXXX", 8) ;
fdc = mkstemp(tmp) ;
if (fdc == -1) qmailr_tempusys("mkstemp ", tmp) ;
smtproutes_compile(fdr, fdc) ;
if (lseek(fdc, 0, SEEK_SET) == -1) qmailr_tempusys("lseek") ;
if (fsync(fdc) == -1) qmailr_tempusys("fsync ", tmp) ;
fd_close(fdr) ;
if (rename(tmp, cdbfile) == -1) unlink_void(tmp) ;
}
useit:
if (!cdb_init_fromfd(&routes->map, fdc)) qmailr_tempusys("mmap ", "run/qmail-remote/smtproutes.cdb") ;
fd_close(fdc) ;
fd_close(fdl) ;
return 1 ;
zero:
fd_close(fdl) ;
errno = 0 ;
return 0 ;
}
int smtproutes_match (smtproutes const *routes, char const *s, stralloc *sa, size_t *pos, uint16_t *port)
{
cdb_data data ;
int r = cdb_find(&routes->map, &data, s, strlen(s)) ;
if (r == -1) qmailr_temp("Invalid run/qmail-remote/smtproutes.cdb") ;
if (!r) return 0 ;
if (data.len < 3) return 0 ;
if (data.s[data.len - 1]) qmailr_temp("Invalid ", "run/qmail-remote/smtproutes.cdb") ;
LOLDEBUG("found: key %s has relay %s", s, data.s + 2)
*pos = sa->len ;
uint16_unpack_big(data.s, port) ;
if (!stralloc_catb(sa, data.s + 2, data.len - 2)) dienomem() ;
return 1 ;
}
void smtproutes_free (smtproutes *routes)
{
cdb_free(&routes->map) ;
}
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