altcp: support for setting keepalive parameters

(cherry picked from commit b04d8a6a6caed42ea05e37b2d93b421de554f6df)

src/apps/altcp_tls/altcp_tls_mbedtls.c

@@ -1256,6 +1256,10 @@ const struct altcp_functions altcp_mbedtls_functions = {
   altcp_default_get_tcp_addrinfo,
   altcp_default_get_ip,
   altcp_default_get_port
+#if LWIP_TCP_KEEPALIVE
+  , altcp_default_keepalive_disable
+  , altcp_default_keepalive_enable
+#endif
 #ifdef LWIP_DEBUG
   , altcp_default_dbg_get_tcp_state
 #endif

src/core/altcp.c

@@ -501,6 +501,24 @@ altcp_get_port(struct altcp_pcb *conn, int local)
   return 0;
 }
 
+#if LWIP_TCP_KEEPALIVE
+void
+altcp_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->keepalive_disable) {
+    conn->fns->keepalive_disable(conn);
+  }
+}
+
+void
+altcp_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count)
+{
+  if (conn && conn->fns && conn->fns->keepalive_enable) {
+      conn->fns->keepalive_enable(conn, idle, intvl, count);
+  }
+}
+#endif
+
 #ifdef LWIP_DEBUG
 enum tcp_state
 altcp_dbg_get_tcp_state(struct altcp_pcb *conn)
@@ -666,6 +684,24 @@ altcp_default_get_port(struct altcp_pcb *conn, int local)
   return 0;
 }
 
+#if LWIP_TCP_KEEPALIVE
+void
+altcp_default_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    altcp_keepalive_disable(conn->inner_conn);
+  }
+}
+
+void
+altcp_default_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count)
+{
+  if (conn && conn->inner_conn) {
+      altcp_keepalive_enable(conn->inner_conn, idle, intvl, count);
+  }
+}
+#endif
+
 #ifdef LWIP_DEBUG
 enum tcp_state
 altcp_default_dbg_get_tcp_state(struct altcp_pcb *conn)

src/core/altcp_tcp.c

@@ -49,6 +49,7 @@
 #include "lwip/altcp_tcp.h"
 #include "lwip/priv/altcp_priv.h"
 #include "lwip/tcp.h"
+#include "lwip/priv/tcp_priv.h"
 #include "lwip/mem.h"
 
 #include <string.h>
@@ -446,6 +447,31 @@ altcp_tcp_setprio(struct altcp_pcb *conn, u8_t prio)
   }
 }
 
+#if LWIP_TCP_KEEPALIVE
+static void
+altcp_tcp_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    ip_reset_option(pcb, SOF_KEEPALIVE);
+  }
+}
+
+static void
+altcp_tcp_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t cnt)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    ip_set_option(pcb, SOF_KEEPALIVE);
+    pcb->keep_idle = idle ? idle : TCP_KEEPIDLE_DEFAULT;
+    pcb->keep_intvl = intvl ? intvl : TCP_KEEPINTVL_DEFAULT;
+    pcb->keep_cnt = cnt ? cnt : TCP_KEEPCNT_DEFAULT;
+  }
+}
+#endif
+
 static void
 altcp_tcp_dealloc(struct altcp_pcb *conn)
 {
@@ -535,6 +561,10 @@ const struct altcp_functions altcp_tcp_functions = {
   altcp_tcp_get_tcp_addrinfo,
   altcp_tcp_get_ip,
   altcp_tcp_get_port
+#if LWIP_TCP_KEEPALIVE
+  , altcp_tcp_keepalive_disable
+  , altcp_tcp_keepalive_enable
+#endif
 #ifdef LWIP_DEBUG
   , altcp_tcp_dbg_get_tcp_state
 #endif

src/include/lwip/altcp.h

@@ -129,6 +129,11 @@ err_t altcp_get_tcp_addrinfo(struct altcp_pcb *conn, int local, ip_addr_t *addr,
 ip_addr_t *altcp_get_ip(struct altcp_pcb *conn, int local);
 u16_t altcp_get_port(struct altcp_pcb *conn, int local);
 
+#if LWIP_TCP_KEEPALIVE
+void  altcp_keepalive_disable(struct altcp_pcb *conn);
+void  altcp_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count);
+#endif
+
 #ifdef LWIP_DEBUG
 enum tcp_state altcp_dbg_get_tcp_state(struct altcp_pcb *conn);
 #endif

src/include/lwip/priv/altcp_priv.h

@@ -85,6 +85,11 @@ typedef err_t (*altcp_get_tcp_addrinfo_fn)(struct altcp_pcb *conn, int local, ip
 typedef ip_addr_t *(*altcp_get_ip_fn)(struct altcp_pcb *conn, int local);
 typedef u16_t (*altcp_get_port_fn)(struct altcp_pcb *conn, int local);
 
+#if LWIP_TCP_KEEPALIVE
+typedef void  (*altcp_keepalive_disable_fn)(struct altcp_pcb *conn);
+typedef void  (*altcp_keepalive_enable_fn)(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count);
+#endif
+
 #ifdef LWIP_DEBUG
 typedef enum tcp_state (*altcp_dbg_get_tcp_state_fn)(struct altcp_pcb *conn);
 #endif
@@ -111,6 +116,10 @@ struct altcp_functions {
   altcp_get_tcp_addrinfo_fn   addrinfo;
   altcp_get_ip_fn             getip;
   altcp_get_port_fn           getport;
+#if LWIP_TCP_KEEPALIVE
+  altcp_keepalive_disable_fn  keepalive_disable;
+  altcp_keepalive_enable_fn   keepalive_enable;
+#endif
 #ifdef LWIP_DEBUG
   altcp_dbg_get_tcp_state_fn  dbg_get_tcp_state;
 #endif
@@ -133,6 +142,10 @@ void  altcp_default_dealloc(struct altcp_pcb *conn);
 err_t altcp_default_get_tcp_addrinfo(struct altcp_pcb *conn, int local, ip_addr_t *addr, u16_t *port);
 ip_addr_t *altcp_default_get_ip(struct altcp_pcb *conn, int local);
 u16_t altcp_default_get_port(struct altcp_pcb *conn, int local);
+#if LWIP_TCP_KEEPALIVE
+void  altcp_default_keepalive_disable(struct altcp_pcb *conn);
+void  altcp_default_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count);
+#endif
 #ifdef LWIP_DEBUG
 enum tcp_state altcp_default_dbg_get_tcp_state(struct altcp_pcb *conn);
 #endif