From fc117e73029e73401f08d459fef4050e659e6c11 Mon Sep 17 00:00:00 2001
From: Mike Brady <4265913+mikebrady@users.noreply.github.com>
Date: Wed, 16 Nov 2022 14:25:53 +0000
Subject: [PATCH] Modify the generation of the 12-digit classic AirPlay service
 name prefix so that it depends on the service name as well as the hardware
 address.

---
 mdns.c      | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 shairport.c | 37 +++----------------------------------
 2 files changed, 54 insertions(+), 35 deletions(-)

diff --git a/mdns.c b/mdns.c
index 9a5465c1..5dbbc102 100644
--- a/mdns.c
+++ b/mdns.c
@@ -48,6 +48,19 @@ extern mdns_backend mdns_external_avahi;
 extern mdns_backend mdns_external_dns_sd;
 #endif
 
+#ifdef CONFIG_MBEDTLS
+#include <mbedtls/md5.h>
+#include <mbedtls/version.h>
+#endif
+
+#ifdef CONFIG_POLARSSL
+#include <polarssl/md5.h>
+#endif
+
+#ifdef CONFIG_OPENSSL
+#include <openssl/md5.h>
+#endif
+
 static mdns_backend *mdns_backends[] = {
 #ifdef CONFIG_AVAHI
     &mdns_avahi,
@@ -65,11 +78,48 @@ static mdns_backend *mdns_backends[] = {
     NULL};
 
 void mdns_register(char **txt_records, char **secondary_txt_records) {
+
+  // calculate the 12-hex-digit prefix by hashing the service name.
+  uint8_t ap_md5[16];
+
+debug(1,"size of hw_addr is %u.", sizeof(config.hw_addr));
+#ifdef CONFIG_OPENSSL
+  MD5_CTX ctx;
+  MD5_Init(&ctx);
+  MD5_Update(&ctx, config.service_name, strlen(config.service_name));
+  MD5_Update(&ctx, config.hw_addr, sizeof(config.hw_addr));
+  MD5_Final(ap_md5, &ctx);
+#endif
+
+#ifdef CONFIG_MBEDTLS
+#if MBEDTLS_VERSION_MINOR >= 7
+  mbedtls_md5_context tctx;
+  mbedtls_md5_starts_ret(&tctx);
+  mbedtls_md5_update_ret(&tctx, (unsigned char *)config.service_name, strlen(config.service_name));
+  mbedtls_md5_update_ret(&tctx, (unsigned char *)config.hw_addr, sizeof(config.hw_addr));
+  mbedtls_md5_finish_ret(&tctx, ap_md5);
+#else
+  mbedtls_md5_context tctx;
+  mbedtls_md5_starts(&tctx);
+  mbedtls_md5_update(&tctx, (unsigned char *)config.service_name, strlen(config.service_name));
+  mbedtls_md5_update(&tctx, (unsigned char *)config.hw_addr, sizeof(config.hw_addr));
+  mbedtls_md5_finish(&tctx, ap_md5);
+#endif
+#endif
+
+#ifdef CONFIG_POLARSSL
+  md5_context tctx;
+  md5_starts(&tctx);
+  md5_update(&tctx, (unsigned char *)config.service_name, strlen(config.service_name));
+  md5_update(&tctx, (unsigned char *)config.hw_addr, sizeof(config.hw_addr));
+  md5_finish(&tctx, ap_md5);
+#endif
+
   char *ap1_service_name = alloca(strlen(config.service_name) + 14);
   char *p = ap1_service_name;
   int i;
   for (i = 0; i < 6; i++) {
-    snprintf(p, 3, "%02X", config.hw_addr[i]);
+    snprintf(p, 3, "%02X", ap_md5[i]);
     p += 2;
   }
   *p++ = '@';
diff --git a/shairport.c b/shairport.c
index 2ccf40ce..ac40c11f 100644
--- a/shairport.c
+++ b/shairport.c
@@ -2454,35 +2454,6 @@ int main(int argc, char **argv) {
   soxr_time_check_thread_started = 1;
 #endif
 
-  /*
-    uint8_t ap_md5[16];
-
-  #ifdef CONFIG_OPENSSL
-    MD5_CTX ctx;
-    MD5_Init(&ctx);
-    MD5_Update(&ctx, config.service_name, strlen(config.service_name));
-    MD5_Final(ap_md5, &ctx);
-  #endif
-
-  #ifdef CONFIG_MBEDTLS
-  #if MBEDTLS_VERSION_MINOR >= 7
-    mbedtls_md5_context tctx;
-    mbedtls_md5_starts_ret(&tctx);
-    mbedtls_md5_update_ret(&tctx, (unsigned char *)config.service_name,
-  strlen(config.service_name)); mbedtls_md5_finish_ret(&tctx, ap_md5); #else mbedtls_md5_context
-  tctx; mbedtls_md5_starts(&tctx); mbedtls_md5_update(&tctx, (unsigned char *)config.service_name,
-  strlen(config.service_name)); mbedtls_md5_finish(&tctx, ap_md5); #endif #endif
-
-  #ifdef CONFIG_POLARSSL
-    md5_context tctx;
-    md5_starts(&tctx);
-    md5_update(&tctx, (unsigned char *)config.service_name, strlen(config.service_name));
-    md5_finish(&tctx, ap_md5);
-  #endif
-
-    memcpy(config.hw_addr, ap_md5, sizeof(config.hw_addr));
-  */
-
 #ifdef CONFIG_METADATA
   metadata_init(); // create the metadata pipe if necessary
 #endif
@@ -2540,12 +2511,10 @@ int main(int argc, char **argv) {
 #ifdef CONFIG_METADATA
   send_ssnc_metadata('svna', config.service_name, strlen(config.service_name), 1);
   char buffer[256] = "";
-  snprintf(buffer, sizeof(buffer), "%d",
-           config.output_rate);
+  snprintf(buffer, sizeof(buffer), "%d", config.output_rate);
   send_ssnc_metadata('ofps', buffer, strlen(buffer), 1);
-  snprintf(buffer, sizeof(buffer), "%s",
-           sps_format_description_string(config.output_format));  
-  send_ssnc_metadata('ofmt', buffer, strlen(buffer), 1);  
+  snprintf(buffer, sizeof(buffer), "%s", sps_format_description_string(config.output_format));
+  send_ssnc_metadata('ofmt', buffer, strlen(buffer), 1);
 #endif
 
   activity_monitor_start(); // not yet for AP2
-- 
2.47.3