From 0ff826697221492791ec19c71205457ba2db678a Mon Sep 17 00:00:00 2001
From: me-no-dev <hristo@espressif.com>
Date: Wed, 10 Jul 2024 12:28:38 +0300
Subject: [PATCH] Add patch to fix the maximum number of TCP PCBs in TIME_WAIT

---
 patches/lwip_max_tcp_pcb.diff | 118 ++++++++++++++++++++++++++++++++++
 tools/install-esp-idf.sh      |   1 +
 2 files changed, 119 insertions(+)
 create mode 100644 patches/lwip_max_tcp_pcb.diff

diff --git a/patches/lwip_max_tcp_pcb.diff b/patches/lwip_max_tcp_pcb.diff
new file mode 100644
index 000000000..6b9e73cb6
--- /dev/null
+++ b/patches/lwip_max_tcp_pcb.diff
@@ -0,0 +1,118 @@
+diff --git a/components/lwip/lwip/src/core/memp.c b/components/lwip/lwip/src/core/memp.c
+index 352ce5a55127a658b6b3c9d8541298c42df332ff..39433cf476b3456b046e337e9b1f016299964a84 100644
+--- a/components/lwip/lwip/src/core/memp.c
++++ b/components/lwip/lwip/src/core/memp.c
+@@ -240,6 +240,10 @@ memp_init(void)
+ #endif /* MEMP_OVERFLOW_CHECK >= 2 */
+ }
+ 
++#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
++static u32_t num_tcp_pcb = 0;
++#endif
++
+ static void *
+ #if !MEMP_OVERFLOW_CHECK
+ do_memp_malloc_pool(const struct memp_desc *desc)
+@@ -251,6 +255,16 @@ do_memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int
+   SYS_ARCH_DECL_PROTECT(old_level);
+ 
+ #if MEMP_MEM_MALLOC
++#if ESP_LWIP
++#if LWIP_TCP
++  if(desc == memp_pools[MEMP_TCP_PCB]){
++    if(num_tcp_pcb >= MEMP_NUM_TCP_PCB){
++        return NULL;
++    }
++  }
++#endif
++#endif
++
+   memp = (struct memp *)mem_malloc(MEMP_SIZE + MEMP_ALIGN_SIZE(desc->size));
+   SYS_ARCH_PROTECT(old_level);
+ #else /* MEMP_MEM_MALLOC */
+@@ -260,6 +274,12 @@ do_memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int
+ #endif /* MEMP_MEM_MALLOC */
+ 
+   if (memp != NULL) {
++#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
++  if (desc == memp_pools[MEMP_TCP_PCB]) {
++    num_tcp_pcb++;
++  }
++#endif
++
+ #if !MEMP_MEM_MALLOC
+ #if MEMP_OVERFLOW_CHECK == 1
+     memp_overflow_check_element(memp, desc);
+@@ -369,6 +389,12 @@ do_memp_free_pool(const struct memp_desc *desc, void *mem)
+ 
+   SYS_ARCH_PROTECT(old_level);
+ 
++#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
++  if (desc == memp_pools[MEMP_TCP_PCB]) {
++    num_tcp_pcb--;
++  }
++#endif
++
+ #if MEMP_OVERFLOW_CHECK == 1
+   memp_overflow_check_element(memp, desc);
+ #endif /* MEMP_OVERFLOW_CHECK */
+diff --git a/components/lwip/lwip/src/core/tcp.c b/components/lwip/lwip/src/core/tcp.c
+index 3fbdd89ae07807208ff7466abb50f90b5e7727e4..fe6baaf250927cb4b89f8d1dbd41c73def88692b 100644
+--- a/components/lwip/lwip/src/core/tcp.c
++++ b/components/lwip/lwip/src/core/tcp.c
+@@ -1765,7 +1765,9 @@ tcp_kill_state(enum tcp_state state)
+   struct tcp_pcb *pcb, *inactive;
+   u32_t inactivity;
+ 
++#if !ESP_LWIP
+   LWIP_ASSERT("invalid state", (state == CLOSING) || (state == LAST_ACK));
++#endif
+ 
+   inactivity = 0;
+   inactive = NULL;
+@@ -1870,17 +1872,41 @@ tcp_alloc(u8_t prio)
+         tcp_kill_state(CLOSING);
+         /* Try to allocate a tcp_pcb again. */
+         pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
++#if ESP_LWIP
+         if (pcb == NULL) {
+-          /* Try killing oldest active connection with lower priority than the new one. */
+-          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
+-          tcp_kill_prio(prio);
+-          /* Try to allocate a tcp_pcb again. */
++          /* Try killing oldest connection in FIN_WAIT_2. */
++          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_2 connection\n"));
++          tcp_kill_state(FIN_WAIT_2);
+           pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
++          if (pcb == NULL) {
++            /* Try killing oldest connection in FIN_WAIT_1. */
++            LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_1 connection\n"));
++            tcp_kill_state(FIN_WAIT_1);
++            pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
++#endif
++            if (pcb == NULL) {
++              /* Try killing oldest active connection with lower priority than the new one. */
++              LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
++              tcp_kill_prio(prio);
++              /* Try to allocate a tcp_pcb again. */
++              pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
++              if (pcb != NULL) {
++                /* adjust err stats: memp_malloc failed multiple times before */
++                MEMP_STATS_DEC(err, MEMP_TCP_PCB);
++              }
++            }
++#if ESP_LWIP
++            if (pcb != NULL) {
++            /* adjust err stats: memp_malloc failed multiple times before */
++            MEMP_STATS_DEC(err, MEMP_TCP_PCB);
++            }
++          }
+           if (pcb != NULL) {
+             /* adjust err stats: memp_malloc failed multiple times before */
+             MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+           }
+         }
++#endif
+         if (pcb != NULL) {
+           /* adjust err stats: memp_malloc failed multiple times before */
+           MEMP_STATS_DEC(err, MEMP_TCP_PCB);
diff --git a/tools/install-esp-idf.sh b/tools/install-esp-idf.sh
index 95b5e5587..858e1381f 100755
--- a/tools/install-esp-idf.sh
+++ b/tools/install-esp-idf.sh
@@ -39,6 +39,7 @@ if [ ! -x $idf_was_installed ] || [ ! -x $commit_predefined ]; then
 	cd $IDF_PATH
 	patch -p1 -N -i ../patches/esp32s2_i2c_ll_master_init.diff
 	patch -p1 -N -i ../patches/mmu_map.diff
+	patch -p1 -N -i ../patches/lwip_max_tcp_pcb.diff
 	cd -
 fi