1 files changed, 31 insertions, 0 deletions
diff --git a/src/network/dns_parse.c b/src/network/dns_parse.c
new file mode 100644
index 00000000..aa0d39f3
--- /dev/null
+++ b/src/network/dns_parse.c
@@ -0,0 +1,31 @@
+#include <string.h>
+
+int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx)
+{
+	int qdcount, ancount;
+	const unsigned char *p;
+	int len;
+
+	if ((r[3]&15)) return 0;
+	p = r+12;
+	qdcount = r[4]*256 + r[5];
+	ancount = r[6]*256 + r[7];
+	if (qdcount+ancount > 64) return -1;
+	while (qdcount--) {
+		while (p-r < rlen && *p-1U < 127) p++;
+		if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
+			return -1;
+		p += 5 + !!*p;
+	}
+	while (ancount--) {
+		while (p-r < rlen && *p-1U < 127) p++;
+		if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
+			return -1;
+		p += 1 + !!*p;
+		len = p[8]*256 + p[9];
+		if (p+len > r+rlen) return -1;
+		if (callback(ctx, p[1], p+10, len, r) < 0) return -1;
+		p += 10 + len;
+	}
+	return 0;
+}