From 0ff56f284d1807e037b1f650607502114c5d4547 Mon Sep 17 00:00:00 2001
From: chrysn <chrysn@fsfe.org>
Date: Mon, 1 Mar 2021 12:21:45 +0100
Subject: [PATCH] sys/net/app/cord: Support the addition of extra registration
 arguments

---
 sys/include/net/cord/config.h                    | 16 ++++++++++++++++
 .../application_layer/cord/common/cord_common.c  | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/sys/include/net/cord/config.h b/sys/include/net/cord/config.h
index 56ed8b3e96..b6f7a47ba6 100644
--- a/sys/include/net/cord/config.h
+++ b/sys/include/net/cord/config.h
@@ -91,6 +91,22 @@ extern "C" {
 #endif
 /** @} */
 
+/**
+ * @brief   Extra query parameters added during registration
+ *
+ * Must be suitable for constructing a static array out of them.
+ *
+ * Example:
+ *
+ * ```
+ * CFLAGS += '-DCONFIG_CORD_EXTRAARGS="proxy=on","et=tag:riot-os.org,2020:board"'
+ * ```
+ */
+#ifdef DOXYGEN
+#define CONFIG_CORD_EXTRAARGS
+#endif
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/sys/net/application_layer/cord/common/cord_common.c b/sys/net/application_layer/cord/common/cord_common.c
index 73815f5e28..63985eab59 100644
--- a/sys/net/application_layer/cord/common/cord_common.c
+++ b/sys/net/application_layer/cord/common/cord_common.c
@@ -79,5 +79,15 @@ int cord_common_add_qstring(coap_pkt_t *pkt)
     }
 #endif
 
+#ifdef CONFIG_CORD_EXTRAARGS
+    static const char *extra[] = { CONFIG_CORD_EXTRAARGS };
+    for (unsigned i = 0; i < ARRAY_SIZE(extra); ++i) {
+        res = coap_opt_add_uri_query(pkt, extra[i], NULL);
+        if (res < 0) {
+            return res;
+        }
+    }
+#endif
+
     return 0;
 }