1 files changed, 116 insertions, 0 deletions
diff --git a/rbldns.c b/rbldns.c
new file mode 100644
index 0000000..2c13c27
--- /dev/null
+++ b/rbldns.c
@@ -0,0 +1,116 @@
+#include <unistd.h>
+#include "str.h"
+#include "byte.h"
+#include "ip4.h"
+#include "open.h"
+#include "env.h"
+#include "cdb.h"
+#include "dns.h"
+#include "dd.h"
+#include "strerr.h"
+#include "response.h"
+
+static char *base;
+
+static struct cdb c;
+static char key[5];
+static char data[100 + IP4_FMT];
+
+static int doit(char *q,char qtype[2])
+{
+  int flaga;
+  int flagtxt;
+  char ch;
+  char reverseip[4];
+  char ip[4];
+  uint32 ipnum;
+  int r;
+  uint32 dlen;
+  int i;
+
+  flaga = byte_equal(qtype,2,DNS_T_A);
+  flagtxt = byte_equal(qtype,2,DNS_T_TXT);
+  if (byte_equal(qtype,2,DNS_T_ANY)) flaga = flagtxt = 1;
+  if (!flaga && !flagtxt) goto REFUSE;
+
+  if (dd(q,base,reverseip) != 4) goto REFUSE;
+  uint32_unpack(reverseip,&ipnum);
+  uint32_pack_big(ip,ipnum);
+
+  for (i = 0;i <= 24;++i) {
+    ipnum >>= i;
+    ipnum <<= i;
+    uint32_pack_big(key,ipnum);
+    key[4] = 32 - i;
+    r = cdb_find(&c,key,5);
+    if (r == -1) return 0;
+    if (r) break;
+  }
+  if (!r) { response_nxdomain(); return 1; }
+
+  r = cdb_find(&c,"",0);
+  if (r == -1) return 0;
+  if (r && ((dlen = cdb_datalen(&c)) >= 4)) {
+    if (dlen > 100) dlen = 100;
+    if (cdb_read(&c,data,dlen,cdb_datapos(&c)) == -1) return 0;
+  }
+  else {
+    dlen = 12;
+    byte_copy(data,dlen,"\177\0\0\2Listed $");
+  }
+
+  if ((dlen >= 5) && (data[dlen - 1] == '$')) {
+    --dlen;
+    dlen += ip4_fmt(data + dlen,ip);
+  }
+
+  if (flaga) {
+    if (!response_rstart(q,DNS_T_A,2048)) return 0;
+    if (!response_addbytes(data,4)) return 0;
+    response_rfinish(RESPONSE_ANSWER);
+  }
+  if (flagtxt) {
+    if (!response_rstart(q,DNS_T_TXT,2048)) return 0;
+    ch = dlen - 4;
+    if (!response_addbytes(&ch,1)) return 0;
+    if (!response_addbytes(data + 4,dlen - 4)) return 0;
+    response_rfinish(RESPONSE_ANSWER);
+  }
+
+  return 1;
+
+
+  REFUSE:
+  response[2] &= ~4;
+  response[3] &= ~15;
+  response[3] |= 5;
+  return 1;
+}
+
+int respond(char *q,char qtype[2],char ip[4])
+{
+  int fd;
+  int result;
+
+  fd = open_read("data.cdb");
+  if (fd == -1) return 0;
+  cdb_init(&c,fd);
+  result = doit(q,qtype);
+  cdb_free(&c);
+  close(fd);
+  return result;
+}
+
+const char *fatal = "rbldns: fatal: ";
+const char *starting = "starting rbldns\n";
+
+void initialize(void)
+{
+  char *x;
+
+  x = env_get("BASE");
+  if (!x)
+    strerr_die2x(111,fatal,"$BASE not set");
+  if (!dns_domain_fromdot(&base,x,str_len(x)))
+    strerr_die2x(111,fatal,"unable to parse $BASE");
+}