From 4c58c62cfe9a6aa73508b7598e32276cfe83c523 Mon Sep 17 00:00:00 2001
From: "Sergio R. Caprile" <scaprile@cesanta.com>
Date: Wed, 26 Apr 2023 15:09:27 -0300
Subject: [PATCH] Fix UDP listeners

---
 mongoose.c        | 4 +++-
 src/tcpip/tcpip.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/mongoose.c b/mongoose.c
index 1cc814e4..5e544ad8 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -7848,9 +7848,11 @@ static void rx_udp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
   struct mg_connection *c = getpeer(ifp->mgr, pkt, true);
   if (c == NULL) {
     // No UDP listener on this port. Should send ICMP, but keep silent.
-  } else if (c != NULL) {
+  } else {
     c->rem.port = pkt->udp->sport;
     c->rem.ip = pkt->ip->src;
+    struct connstate *s = (struct connstate *) (c + 1);
+    memcpy(s->mac, pkt->eth->src, sizeof(s->mac));
     if (c->recv.len >= MG_MAX_RECV_SIZE) {
       mg_error(c, "max_recv_buf_size reached");
     } else if (c->recv.size - c->recv.len < pkt->pay.len &&
diff --git a/src/tcpip/tcpip.c b/src/tcpip/tcpip.c
index d6649861..904d57f5 100644
--- a/src/tcpip/tcpip.c
+++ b/src/tcpip/tcpip.c
@@ -404,9 +404,11 @@ static void rx_udp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
   struct mg_connection *c = getpeer(ifp->mgr, pkt, true);
   if (c == NULL) {
     // No UDP listener on this port. Should send ICMP, but keep silent.
-  } else if (c != NULL) {
+  } else {
     c->rem.port = pkt->udp->sport;
     c->rem.ip = pkt->ip->src;
+    struct connstate *s = (struct connstate *) (c + 1);
+    memcpy(s->mac, pkt->eth->src, sizeof(s->mac));
     if (c->recv.len >= MG_MAX_RECV_SIZE) {
       mg_error(c, "max_recv_buf_size reached");
     } else if (c->recv.size - c->recv.len < pkt->pay.len &&