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/* ISC license. */
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <skalibs/posixplz.h>
#include <skalibs/uint16.h>
#include <skalibs/uint32.h>
#include <skalibs/types.h>
#include <skalibs/error.h>
#include <skalibs/strerr.h>
#include <skalibs/sgetopt.h>
#include <skalibs/tai.h>
#include <skalibs/socket.h>
#include <skalibs/ip46.h>
#include <skalibs/cdb.h>
#include <skalibs/sig.h>
#include <s6/accessrules.h>
#include <shibari/common.h>
#include <shibari/server.h>
#define USAGE "shibari-server-udp [ -v verbosity ] [ -d notif ] [ -f cdbfile ] [ -i rulesdir | -x rulesfile ] [ -p port ] ip"
#define dieusage() strerr_dieusage(100, USAGE)
#define VAR "LOC"
static char const *tdbfile = "data.cdb" ;
static cdb tdb = CDB_ZERO ;
static cdb rules = CDB_ZERO ;
static char const *rulesfile = 0 ;
static unsigned int rulestype = 0 ;
static int cont = 1 ;
static uint32_t verbosity = 1 ;
static void on_term (int s)
{
(void)s ;
cont = 0 ;
}
static void on_hup (int s)
{
cdb newtdb = CDB_ZERO ;
(void)s ;
if (!cdb_init(&newtdb, tdbfile))
{
if (verbosity) strerr_warnwu2sys("reopen DNS data file ", tdbfile) ;
}
else
{
cdb_free(&tdb) ;
tdb = newtdb ;
}
if (rulestype == 2)
{
cdb newrules = CDB_ZERO ;
if (!cdb_init(&newrules, rulesfile))
{
if (verbosity) strerr_warnwu2sys("reopen access rules file ", rulesfile) ;
}
else
{
cdb_free(&rules) ;
rules = newrules ;
}
}
}
static int check_rules (ip46 const *remoteip, s6_accessrules_params_t *params, char const **loc)
{
s6_accessrules_result_t r ;
params->env.len = 0 ;
params->exec.len = 0 ;
r = rulestype == 2 ?
s6_accessrules_ip46_cdb(remoteip, &rules, params) :
s6_accessrules_ip46_fs(remoteip, rulesfile, params) ;
if (r != S6_ACCESSRULES_ALLOW) return 0 ;
if (params->env.len)
{
char const *p ;
if (params->env.s[params->env.len - 1])
{
if (verbosity)
{
char fmt[IP46_FMT] ;
fmt[ip46_fmt(fmt, remoteip)] = 0 ;
strerr_warnw6x("invalid environment parameters in rules ", rulestype == 2 ? "cdb " : "directory ", rulesfile, " for ip ", fmt, " - denying connection") ;
}
return 0 ;
}
p = memmem(params->env.s, params->env.len - 1, VAR "=", sizeof(VAR)) ;
if (p && (p == params->env.s || !p[-1])) *loc = p + sizeof(VAR) ;
}
return 1 ;
}
int main (int argc, char const *const *argv)
{
s6_accessrules_params_t params = S6_ACCESSRULES_PARAMS_ZERO ;
int s ;
unsigned int notif = 0 ;
char buf[512] ;
shibari_packet pkt = SHIBARI_PACKET_INIT(buf, 512, 0) ;
uint16_t localport = 53 ;
ip46 localip ;
PROG = "shibari-server-udp" ;
{
subgetopt l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "v:d:f:i:x:p:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'v' : if (!uint320_scan(l.arg, &verbosity)) dieusage() ; break ;
case 'd' : if (!uint0_scan(l.arg, ¬if)) dieusage() ; break ;
case 'f' : tdbfile = l.arg ; break ;
case 'i' : rulesfile = l.arg ; rulestype = 1 ; break ;
case 'x' : rulesfile = l.arg ; rulestype = 2 ; break ;
case 'p' : if (!uint160_scan(l.arg, &localport)) dieusage() ; break ;
default : strerr_dieusage(10, USAGE) ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (!argc) dieusage() ;
if (!ip46_scan(argv[0], &localip)) dieusage() ;
if (notif)
{
if (notif < 3) strerr_dief1x(100, "notification fd cannot be 0, 1 or 2") ;
if (fcntl(notif, F_GETFD) == -1) strerr_diefu1sys(111, "check notification fd") ;
}
close(0) ;
close(1) ;
s = socket_udp46_b(ip46_is6(&localip)) ;
if (s == -1) strerr_diefu1sys(111, "create socket") ;
if (socket_bind46_reuse(s, &localip, localport) == -1) strerr_diefu1sys(111, "bind socket") ;
if (!cdb_init(&tdb, tdbfile)) strerr_diefu2sys(111, "open cdb file ", tdbfile) ;
if (rulestype == 2 && !cdb_init(&rules, rulesfile)) strerr_diefu2sys(111, "open rules file ", rulesfile) ;
if (!sig_catch(SIGHUP, &on_hup)) strerr_diefu1sys(111, "catch SIGHUP") ;
if (!sig_catch(SIGTERM, &on_term)) strerr_diefu1sys(111, "catch SIGTERM") ;
shibari_log_start(verbosity, &localip, localport) ;
if (notif)
{
write(notif, "\n", 1) ;
close(notif) ;
}
for (; cont ; sig_unblock(SIGHUP))
{
tain wstamp ;
char const *loc = 0 ;
s6dns_message_header_t hdr ;
s6dns_message_counts_t counts ;
s6dns_domain_t name ;
unsigned int rcode ;
ssize_t r ;
uint16_t qtype ;
uint16_t remoteport ;
ip46 remoteip ;
r = socket_recv46(s, buf, 512, &remoteip, &remoteport) ;
if (r == -1) strerr_diefu1sys(111, "recv from socket") ;
if (!r) strerr_dief1x(111, "huh? got EOF on a connection-less socket") ;
sig_block(SIGHUP) ;
if (rulestype && !check_rules(&remoteip, ¶ms, &loc)) continue ;
if (!s6dns_message_parse_init(&hdr, &counts, buf, r, &rcode)) continue ;
if (hdr.opcode) { rcode = 4 ; goto answer ; }
if (!s6dns_message_parse_question(&counts, &name, &qtype, buf, r, &rcode) || !s6dns_domain_encode(&name))
{
rcode = errno == ENOTSUP ? 4 : 1 ;
goto answer ;
}
shibari_log_queryplus(verbosity, &name, qtype, &remoteip, remoteport) ;
tain_wallclock_read(&wstamp) ;
rcode = shibari_packet_tdb_answer_query(&pkt, &tdb, &hdr, &name, qtype, loc, &wstamp) ;
answer:
if (rcode && rcode != 3)
{
shibari_packet_begin(&pkt, hdr.id, &name, qtype) ;
pkt.hdr.rcode = rcode ;
shibari_packet_end(&pkt) ;
}
shibari_log_answer(verbosity, &pkt.hdr, pkt.pos) ;
if (socket_send46(s, buf, pkt.pos, &remoteip, remoteport) < pkt.pos && verbosity)
strerr_warnwu1sys("send answer") ;
}
shibari_log_exit(verbosity, 0) ;
return 0 ;
}
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