fixed bug #36403 "ip4_input() and ip6_input() always pass inp to higher layers": now the accepting netif is passed up, but the input netif is available through ip_current_input_netif() if required.

CHANGELOG

@@ -167,6 +167,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  * ip.h, ip4.c, ip6.c: fixed bug #36403 "ip4_input() and ip6_input() always pass
+    inp to higher layers": now the accepting netif is passed up, but the input
+    netif is available through ip_current_input_netif() if required.
+
   2015-02-11: patch by hichard
   * tcpip.c: fixed bug #43094 "The function tcpip_input() forget to handle IPv6"
 

src/core/ipv4/ip4.c

@@ -553,7 +553,8 @@ ip_input(struct pbuf *p, struct netif *inp)
   ip_debug_print(p);
   LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
 
-  ip_data.current_netif = inp;
+  ip_data.current_netif = netif;
+  ip_data.current_input_netif = inp;
   ip_data.current_ip4_header = iphdr;
   ip_data.current_ip_header_tot_len = IPH_HL(iphdr) * 4;
 
@@ -613,6 +614,7 @@ ip_input(struct pbuf *p, struct netif *inp)
 
   /* @todo: this is not really necessary... */
   ip_data.current_netif = NULL;
+  ip_data.current_input_netif = NULL;
   ip_data.current_ip4_header = NULL;
   ip_data.current_ip_header_tot_len = 0;
   ip_addr_set_any(ip_current_src_addr());

src/core/ipv6/ip6.c

@@ -397,6 +397,7 @@ ip6_input(struct pbuf *p, struct netif *inp)
 
   /* In netif, used in case we need to send ICMPv6 packets back. */
   ip_data.current_netif = inp;
+  ip_data.current_input_netif = inp;
 
   /* match packet against an interface, i.e. is this packet for us? */
   if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
@@ -708,6 +709,7 @@ options_done:
 
 ip6_input_cleanup:
   ip_data.current_netif = NULL;
+  ip_data.current_input_netif = NULL;
   ip_data.current_ip6_header = NULL;
   ip_data.current_ip_header_tot_len = 0;
   ip6_addr_set_any(&ip_data.current_iphdr_src.ip6);

src/include/lwip/ip.h

@@ -116,8 +116,10 @@ struct ip_pcb {
 /* Global variables of this module, kept in a struct for efficient access using base+index. */
 struct ip_globals
 {
-  /** The interface that provided the packet for the current callback invocation. */
+  /** The interface that accepted the packet for the current callback invocation. */
   struct netif *current_netif;
+  /** The interface that received the packet for the current callback invocation. */
+  struct netif *current_input_netif;
   /** Header of the input packet currently being processed. */
   const struct ip_hdr *current_ip4_header;
 #if LWIP_IPV6
@@ -134,10 +136,15 @@ struct ip_globals
 extern struct ip_globals ip_data;
 
 
-/** Get the interface that received the current packet.
+/** Get the interface that accepted the current packet.
+ * This may or may not be the receiving netif, depending on your netif/network setup.
  * This function must only be called from a receive callback (udp_recv,
  * raw_recv, tcp_accept). It will return NULL otherwise. */
 #define ip_current_netif()      (ip_data.current_netif)
+/** Get the interface that received the current packet.
+ * This function must only be called from a receive callback (udp_recv,
+ * raw_recv, tcp_accept). It will return NULL otherwise. */
+#define ip_current_input_netif() (ip_data.current_input_netif)
 /** Get the IP header of the current packet.
  * This function must only be called from a receive callback (udp_recv,
  * raw_recv, tcp_accept). It will return NULL otherwise. */