1 files changed, 75 insertions, 0 deletions
diff --git a/dns_ip.c b/dns_ip.c
new file mode 100644
index 0000000..e7c3a9a
--- /dev/null
+++ b/dns_ip.c
@@ -0,0 +1,75 @@
+#include "stralloc.h"
+#include "uint16.h"
+#include "byte.h"
+#include "dns.h"
+
+int dns_ip4_packet(stralloc *out,const char *buf,unsigned int len)
+{
+  unsigned int pos;
+  char header[12];
+  uint16 numanswers;
+  uint16 datalen;
+
+  if (!stralloc_copys(out,"")) return -1;
+
+  pos = dns_packet_copy(buf,len,0,header,12); if (!pos) return -1;
+  uint16_unpack_big(header + 6,&numanswers);
+  pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
+  pos += 4;
+
+  while (numanswers--) {
+    pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
+    pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) return -1;
+    uint16_unpack_big(header + 8,&datalen);
+    if (byte_equal(header,2,DNS_T_A))
+      if (byte_equal(header + 2,2,DNS_C_IN))
+        if (datalen == 4) {
+	  if (!dns_packet_copy(buf,len,pos,header,4)) return -1;
+	  if (!stralloc_catb(out,header,4)) return -1;
+	}
+    pos += datalen;
+  }
+
+  dns_sortip(out->s,out->len);
+  return 0;
+}
+
+static char *q = 0;
+
+int dns_ip4(stralloc *out,const stralloc *fqdn)
+{
+  unsigned int i;
+  char code;
+  char ch;
+
+  if (!stralloc_copys(out,"")) return -1;
+  code = 0;
+  for (i = 0;i <= fqdn->len;++i) {
+    if (i < fqdn->len)
+      ch = fqdn->s[i];
+    else
+      ch = '.';
+
+    if ((ch == '[') || (ch == ']')) continue;
+    if (ch == '.') {
+      if (!stralloc_append(out,&code)) return -1;
+      code = 0;
+      continue;
+    }
+    if ((ch >= '0') && (ch <= '9')) {
+      code *= 10;
+      code += ch - '0';
+      continue;
+    }
+
+    if (!dns_domain_fromdot(&q,fqdn->s,fqdn->len)) return -1;
+    if (dns_resolve(q,DNS_T_A) == -1) return -1;
+    if (dns_ip4_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
+    dns_transmit_free(&dns_resolve_tx);
+    dns_domain_free(&q);
+    return 0;
+  }
+
+  out->len &= ~3;
+  return 0;
+}