From 578504caef3097747354bf0e0ebe8fc2c6dca77e Mon Sep 17 00:00:00 2001
From: xenia <xenia@awoo.systems>
Date: Tue, 13 Sep 2022 13:55:02 -0400
Subject: [PATCH] handle AAAA (rather, be like idk lol)

---
 src/dns.c     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/dns.h     |  2 ++
 src/iodined.c | 29 ++++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/src/dns.c b/src/dns.c
index 86bb3c2..3f90297 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -227,6 +227,53 @@ int dns_encode(char *buf, size_t buflen, struct query *q, qr_t qr,
 	return len;
 }
 
+/* Only used when iodined gets a AAAA type query */
+/* Mostly same as dns_encode_caa_response() below */
+int dns_encode_aaaa_response(char *buf, size_t buflen, struct query *q,
+			   char *topdomain)
+{
+	HEADER *header;
+	int len;
+	int domain_len;
+	char *p;
+
+	if (buflen < sizeof(HEADER))
+		return 0;
+
+	memset(buf, 0, buflen);
+
+	header = (HEADER*)buf;
+
+	header->id = htons(q->id);
+	header->qr = 1;
+	header->opcode = 0;
+	header->aa = 1;
+	header->tc = 0;
+	header->rd = 0;
+	header->ra = 0;
+
+	p = buf + sizeof(HEADER);
+
+	header->qdcount = htons(1);
+	header->ancount = htons(0);
+
+	domain_len = strlen(q->name) - strlen(topdomain);
+	if (domain_len < 0 || domain_len == 1)
+		return -1;
+	if (strcasecmp(q->name + domain_len, topdomain))
+		return -1;
+	if (domain_len >= 1 && q->name[domain_len - 1] != '.')
+		return -1;
+
+	/* Query section */
+	putname(&p, buflen - (p - buf), q->name);	/* Name */
+	CHECKLEN(4);
+	putshort(&p, q->type);			/* Type */
+	putshort(&p, C_IN);			/* Class */
+
+	len = p - buf;
+	return len;
+}
 /* Only used when iodined gets a CAA type query */
 /* Mostly same as dns_encode_ns_response() below */
 int dns_encode_caa_response(char *buf, size_t buflen, struct query *q,
diff --git a/src/dns.h b/src/dns.h
index 80ac985..8cf06b6 100644
--- a/src/dns.h
+++ b/src/dns.h
@@ -28,6 +28,8 @@ typedef enum {
 extern int dnsc_use_edns0;
 
 int dns_encode(char *, size_t, struct query *, qr_t, const char *, size_t);
+int dns_encode_aaaa_response(char *buf, size_t buflen, struct query *q,
+			   char *topdomain);
 int dns_encode_caa_response(char *buf, size_t buflen, struct query *q,
 			   char *topdomain);
 int dns_encode_ns_response(char *buf, size_t buflen, struct query *q,
diff --git a/src/iodined.c b/src/iodined.c
index 8dc361a..b69cd77 100644
--- a/src/iodined.c
+++ b/src/iodined.c
@@ -1523,7 +1523,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 }
 
 static void
-handle_caa_request(int dns_fd, struct query *q, int topdomain_offset)
+handle_aaaa_request(int dns_fd, struct query *q, int topdomain_offset)
 /* Mostly identical to handle_caa_request() below */
 {
 	char buf[64*1024];
@@ -1531,6 +1531,30 @@ handle_caa_request(int dns_fd, struct query *q, int topdomain_offset)
 	/* Use possibly dynamic top domain in reply */
 	char *resp_domain = q->name + topdomain_offset;
 
+	len = dns_encode_aaaa_response(buf, sizeof(buf), q, resp_domain);
+	if (len < 1) {
+		warnx("dns_encode_caa_response doesn't fit");
+		return;
+	}
+
+	if (debug >= 2) {
+		fprintf(stderr, "TX: client %s, type %d, name %s, %d bytes NS reply\n",
+			format_addr(&q->from, q->fromlen), q->type, q->name, len);
+	}
+	if (sendto(dns_fd, buf, len, 0, (struct sockaddr*)&q->from, q->fromlen) <= 0) {
+		warn("ns reply send error");
+	}
+}
+
+static void
+handle_caa_request(int dns_fd, struct query *q, int topdomain_offset)
+/* Mostly identical to handle_ns_request() below */
+{
+	char buf[64*1024];
+	int len;
+	/* Use possibly dynamic top domain in reply */
+	char *resp_domain = q->name + topdomain_offset;
+
 	len = dns_encode_caa_response(buf, sizeof(buf), q, resp_domain);
 	if (len < 1) {
 		warnx("dns_encode_caa_response doesn't fit");
@@ -1768,6 +1792,9 @@ tunnel_dns(int tun_fd, int dns_fd, struct dnsfd *dns_fds, int bind_fd)
 		case T_CAA:
 			handle_caa_request(dns_fd, &q, domain_len);
 			break;
+		case T_AAAA:
+			handle_aaaa_request(dns_fd, &q, domain_len);
+			break;
 		default:
 			if (debug >= 0) {
 				fprintf(stderr, "WARN: can't handle request of type: %d\n", q.type);