1 files changed, 86 insertions, 0 deletions
diff --git a/dns_rcip.c b/dns_rcip.c
new file mode 100644
index 0000000..97bd8f5
--- /dev/null
+++ b/dns_rcip.c
@@ -0,0 +1,86 @@
+#include "taia.h"
+#include "openreadclose.h"
+#include "byte.h"
+#include "ip4.h"
+#include "env.h"
+#include "dns.h"
+
+static stralloc data = {0};
+
+static int init(char ip[64])
+{
+  int i;
+  int j;
+  int iplen = 0;
+  char *x;
+
+  x = env_get("DNSCACHEIP");
+  if (x)
+    while (iplen <= 60) {
+      if (*x == '.')
+	++x;
+      else {
+        i = ip4_scan(x,ip + iplen);
+	if (!i) break;
+	x += i;
+	iplen += 4;
+      }
+    }
+
+  if (!iplen) {
+    i = openreadclose("/etc/resolv.conf",&data,64);
+    if (i == -1) return -1;
+    if (i) {
+      if (!stralloc_append(&data,"\n")) return -1;
+      i = 0;
+      for (j = 0;j < data.len;++j)
+        if (data.s[j] == '\n') {
+          if (byte_equal("nameserver ",11,data.s + i) || byte_equal("nameserver\t",11,data.s + i)) {
+            i += 10;
+            while ((data.s[i] == ' ') || (data.s[i] == '\t'))
+              ++i;
+            if (iplen <= 60)
+              if (ip4_scan(data.s + i,ip + iplen)) {
+		if (byte_equal(ip + iplen,4,"\0\0\0\0"))
+		  byte_copy(ip + iplen,4,"\177\0\0\1");
+                iplen += 4;
+	      }
+          }
+          i = j + 1;
+        }
+    }
+  }
+
+  if (!iplen) {
+    byte_copy(ip,4,"\177\0\0\1");
+    iplen = 4;
+  }
+  byte_zero(ip + iplen,64 - iplen);
+  return 0;
+}
+
+static int ok = 0;
+static unsigned int uses;
+static struct taia deadline;
+static char ip[64]; /* defined if ok */
+
+int dns_resolvconfip(char s[64])
+{
+  struct taia now;
+
+  taia_now(&now);
+  if (taia_less(&deadline,&now)) ok = 0;
+  if (!uses) ok = 0;
+
+  if (!ok) {
+    if (init(ip) == -1) return -1;
+    taia_uint(&deadline,600);
+    taia_add(&deadline,&now,&deadline);
+    uses = 10000;
+    ok = 1;
+  }
+
+  --uses;
+  byte_copy(s,64,ip);
+  return 0;
+}