diff options
Diffstat (limited to 'src/server/shibari-server-udp.c')
| -rw-r--r-- | src/server/shibari-server-udp.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/src/server/shibari-server-udp.c b/src/server/shibari-server-udp.c new file mode 100644 index 0000000..d834c94 --- /dev/null +++ b/src/server/shibari-server-udp.c @@ -0,0 +1,207 @@ +/* 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 ; +} |