From aea7062223108374586af7f6cec339e4f81ea1c9 Mon Sep 17 00:00:00 2001
From: David van Moolenbroek <david@minix3.org>
Date: Wed, 4 Jan 2017 22:23:29 +0000
Subject: [PATCH] raw: extend support for connected sockets

The support for connecting raw sockets is extended to match the
support for UDP sockets, while keeping the current API unchanged:

- for connected sockets, filter incoming packets on source address;
- use a flag to indicate whether a socket is connected, at no extra
  memory cost; the application may check this flag if needed;
- added raw_disconnect(), which so far existed in documentation only.
---
 src/core/raw.c         | 30 ++++++++++++++++++++++++++++--
 src/include/lwip/raw.h |  6 ++++++
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/core/raw.c b/src/core/raw.c
index 93c65473..6d5746da 100644
--- a/src/core/raw.c
+++ b/src/core/raw.c
@@ -65,7 +65,7 @@
 static struct raw_pcb *raw_pcbs;
 
 static u8_t
-raw_input_match(struct raw_pcb *pcb, u8_t broadcast)
+raw_input_local_match(struct raw_pcb *pcb, u8_t broadcast)
 {
   LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */
 
@@ -157,7 +157,9 @@ raw_input(struct pbuf *p, struct netif *inp)
   /* loop through all raw pcbs until the packet is eaten by one */
   /* this allows multiple pcbs to match against the packet by design */
   while ((eaten == 0) && (pcb != NULL)) {
-    if ((pcb->protocol == proto) && raw_input_match(pcb, broadcast)) {
+    if ((pcb->protocol == proto) && raw_input_local_match(pcb, broadcast) &&
+        (((pcb->flags & RAW_FLAGS_CONNECTED) == 0) ||
+        ip_addr_cmp(&pcb->remote_ip, ip_current_src_addr()))) {
       /* receive callback function available? */
       if (pcb->recv != NULL) {
 #ifndef LWIP_NOASSERT
@@ -237,9 +239,33 @@ raw_connect(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
     return ERR_VAL;
   }
   ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr);
+  pcb->flags |= RAW_FLAGS_CONNECTED;
   return ERR_OK;
 }
 
+/**
+ * @ingroup raw_raw
+ * Disconnect a RAW PCB.
+ *
+ * @param pcb the raw pcb to disconnect.
+ */
+void
+raw_disconnect(struct raw_pcb *pcb)
+{
+  /* reset remote address association */
+#if LWIP_IPV4 && LWIP_IPV6
+  if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
+    ip_addr_copy(pcb->remote_ip, *IP_ANY_TYPE);
+  } else {
+#endif
+    ip_addr_set_any(IP_IS_V6_VAL(pcb->remote_ip), &pcb->remote_ip);
+#if LWIP_IPV4 && LWIP_IPV6
+  }
+#endif
+  /* mark PCB as unconnected */
+  pcb->flags &= ~RAW_FLAGS_CONNECTED;
+}
+
 /**
  * @ingroup raw_raw
  * Set the callback function for received packets that match the
diff --git a/src/include/lwip/raw.h b/src/include/lwip/raw.h
index 30aa1471..00027a86 100644
--- a/src/include/lwip/raw.h
+++ b/src/include/lwip/raw.h
@@ -52,6 +52,8 @@
 extern "C" {
 #endif
 
+#define RAW_FLAGS_CONNECTED 0x01U
+
 struct raw_pcb;
 
 /** Function prototype for raw pcb receive callback functions.
@@ -75,6 +77,7 @@ struct raw_pcb {
   struct raw_pcb *next;
 
   u8_t protocol;
+  u8_t flags;
 
   /** receive callback function */
   raw_recv_fn recv;
@@ -94,12 +97,15 @@ struct raw_pcb * raw_new_ip_type(u8_t type, u8_t proto);
 void             raw_remove     (struct raw_pcb *pcb);
 err_t            raw_bind       (struct raw_pcb *pcb, const ip_addr_t *ipaddr);
 err_t            raw_connect    (struct raw_pcb *pcb, const ip_addr_t *ipaddr);
+void             raw_disconnect (struct raw_pcb *pcb);
 
 err_t            raw_sendto     (struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *ipaddr);
 err_t            raw_send       (struct raw_pcb *pcb, struct pbuf *p);
 
 void             raw_recv       (struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg);
 
+#define          raw_flags(pcb) ((pcb)->flags)
+
 /* The following functions are the lower layer interface to RAW. */
 u8_t             raw_input      (struct pbuf *p, struct netif *inp);
 #define raw_init() /* Compatibility define, no init needed. */