From 8c368827726dcdd6ee8f40dd2091feb1db4e71f8 Mon Sep 17 00:00:00 2001
From: Florian Hoss <flhoit00@hs-esslingen.de>
Date: Mon, 25 Jul 2022 16:28:55 +0200
Subject: [PATCH] Show the packets arriving at LwIP

---
 ESPTest/include/lwip_hooks.h |  3 +++
 ESPTest/src/lwip_hooks.c     | 25 +++++++++++++++++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/ESPTest/include/lwip_hooks.h b/ESPTest/include/lwip_hooks.h
index f261ee9..13ac3a2 100644
--- a/ESPTest/include/lwip_hooks.h
+++ b/ESPTest/include/lwip_hooks.h
@@ -3,7 +3,10 @@
 
 #include "lwip/netif.h"
 #include "lwip/pbuf.h"
+#include "lwip/ip4.h"
+
 #include "esp_log.h"
+#include "esp_err.h"
 
 #ifdef __cplusplus
 extern "C"
diff --git a/ESPTest/src/lwip_hooks.c b/ESPTest/src/lwip_hooks.c
index 72e39ba..e0adda7 100644
--- a/ESPTest/src/lwip_hooks.c
+++ b/ESPTest/src/lwip_hooks.c
@@ -1,7 +1,28 @@
 #include "lwip_hooks.h"
 
+const char *get_protocol(u16_t type)
+{
+    switch (type)
+    {
+    case 1:
+        return "ICMP";
+    case 6:
+        return "TCP";
+    case 17:
+        return "UDP";
+    default:
+        return "-";
+    }
+}
+
 int lwip_hook_ip4_input(struct pbuf *pbuf, struct netif *input_netif)
 {
-    ESP_LOGI("Hook", "Testing...");
-    return 0;
+    const struct ip_hdr *iphdr;
+    char ip_address[IP_HLEN];
+
+    iphdr = (struct ip_hdr *)pbuf->payload;
+    sprintf(ip_address, "%d.%d.%d.%d", ip4_addr1_16_val(iphdr->src), ip4_addr2_16_val(iphdr->src), ip4_addr3_16_val(iphdr->src), ip4_addr4_16_val(iphdr->src));
+    ESP_LOGI("HOOK", "%s: %s",
+             get_protocol((u16_t)IPH_PROTO(iphdr)), ip_address);
+    return ESP_OK;
 }