From dbf3190c4f0f9e9667298d6a5552525b3128436d Mon Sep 17 00:00:00 2001
From: Jop Zitman <jop-zitman@hotmail.com>
Date: Wed, 18 Dec 2024 14:25:42 +0800
Subject: [PATCH] Implement edns0

---
 src/slipstream_client.c | 31 +++++++++++++++++++------------
 src/slipstream_server.c | 11 +++++++++--
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/src/slipstream_client.c b/src/slipstream_client.c
index 0e47237..1271e9e 100644
--- a/src/slipstream_client.c
+++ b/src/slipstream_client.c
@@ -27,9 +27,6 @@ char* client_domain_name = NULL;
 size_t client_domain_name_len = 0;
 
 ssize_t client_encode_segment(picoquic_quic_t* quic, dns_packet_t* packet, size_t* packet_len, const unsigned char* src_buf, size_t src_buf_len) {
-    edns0_opt_t opt;
-    dns_answer_t edns;
-
     char name[255];
     const size_t len = b32_encode(&name[0], (const char*) src_buf, src_buf_len, true, false);
     const size_t encoded_len = slipstream_inline_dotify(name, 255, len);
@@ -39,10 +36,17 @@ ssize_t client_encode_segment(picoquic_quic_t* quic, dns_packet_t* packet, size_
     name[encoded_len + 1 + client_domain_name_len] = '.';
     name[encoded_len + 1 + client_domain_name_len + 1] = '\0';
 
-    dns_question_t domain;
-    domain.name = name;
-    domain.type = RR_TXT;
-    domain.class = CLASS_IN;
+    dns_question_t question;
+    question.name = name;
+    question.type = RR_TXT;
+    question.class = CLASS_IN;
+
+    dns_answer_t edns = {0};
+    edns.opt.name = ".";
+    edns.opt.type = RR_OPT;
+    edns.opt.class = CLASS_UNKNOWN;
+    edns.opt.ttl = 0;
+    edns.opt.udp_payload = 4096;
 
     dns_query_t query = {0};
     query.id = rand() % UINT16_MAX;
@@ -51,11 +55,9 @@ ssize_t client_encode_segment(picoquic_quic_t* quic, dns_packet_t* packet, size_
     query.rd = true;
     query.rcode = RCODE_OKAY;
     query.qdcount = 1;
-    query.questions = &domain;
-    query.arcount = 0; // TODO: set to 1 for EDNS0
-    query.additional = NULL;
-
-    // TODO: add EDNS0
+    query.questions = &question;
+    query.arcount = 1;
+    query.additional = &edns;
 
     const dns_rcode_t rc = dns_encode(packet, packet_len, &query);
     if (rc != RCODE_OKAY) {
@@ -135,6 +137,11 @@ ssize_t client_decode(picoquic_quic_t* quic, unsigned char** dest_buf, const uns
         return -1;
     }
 
+    if (query->rcode != RCODE_OKAY) {
+        fprintf(stderr, "dns record rcode not okay: %d\n", query->rcode);
+        return -1;
+    }
+
     if (query->ancount != 1) {
         fprintf(stderr, "dns record should contain exactly one answer\n");
         return -1;
diff --git a/src/slipstream_server.c b/src/slipstream_server.c
index 0a82e6f..5c44481 100644
--- a/src/slipstream_server.c
+++ b/src/slipstream_server.c
@@ -64,6 +64,13 @@ ssize_t server_encode(picoquic_quic_t* quic, picoquic_cnx_t* cnx, unsigned char*
     answer_txt.text = (char *)src_buf;
     answer_txt.len = src_buf_len;
 
+    dns_answer_t edns = {0};
+    edns.opt.name = ".";
+    edns.opt.type = RR_OPT;
+    edns.opt.class = CLASS_UNKNOWN;
+    edns.opt.ttl = 0;
+    edns.opt.udp_payload = 4096;
+
     dns_query_t response = {0};
     response.id = query->id;
     response.query = false;
@@ -74,8 +81,8 @@ ssize_t server_encode(picoquic_quic_t* quic, picoquic_cnx_t* cnx, unsigned char*
     response.questions = query->questions;
     response.ancount = 1;
     response.answers = (dns_answer_t *)&answer_txt;
-    response.arcount = 0; // TODO: set to 1 for EDNS0
-    response.additional = NULL;
+    response.arcount = 1;
+    response.additional = &edns;
 
     dns_packet_t* packet = malloc(MAX_UDP_PACKET_SIZE);
     size_t packet_len = MAX_UDP_PACKET_SIZE;