From 2197f9c16a23c93cff88ec4394a45b29586b15a0 Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Date: Mon, 9 May 2022 23:33:19 +0200
Subject: [PATCH] grnc_sock_ip: implement SOCK_AUX_SET_LOCAL

---
 sys/net/gnrc/sock/ip/gnrc_sock_ip.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/net/gnrc/sock/ip/gnrc_sock_ip.c b/sys/net/gnrc/sock/ip/gnrc_sock_ip.c
index ac649d3c54..448f71a875 100644
--- a/sys/net/gnrc/sock/ip/gnrc_sock_ip.c
+++ b/sys/net/gnrc/sock/ip/gnrc_sock_ip.c
@@ -223,6 +223,13 @@ ssize_t sock_ip_send_aux(sock_ip_t *sock, const void *data, size_t len,
         }
         memcpy(&local, &sock->local, sizeof(local));
     }
+#if IS_USED(MODULE_SOCK_AUX_LOCAL)
+    /* user supplied local endpoint takes precedent */
+    if ((aux != NULL) && (aux->flags & SOCK_AUX_SET_LOCAL)) {
+        local = aux->local;
+        aux->flags &= ~SOCK_AUX_SET_LOCAL;
+    }
+#endif
     if (remote == NULL) {
         /* sock can't be NULL at this point */
         memcpy(&rem, &sock->remote, sizeof(rem));