Modern eth_type_trans adds some functionality for DSA tagging.

Mark that we would like to use that functionality.

config-linuxmodule.h.in

@@ -94,6 +94,12 @@
 /* Define if you have the netdev_get_tx_queue function. */
 #undef HAVE_NETDEV_GET_TX_QUEUE
 
+/* Define if you have the netdev_uses_dsa_tags function. */
+#undef HAVE_NETDEV_USES_DSA_TAGS
+
+/* Define if you have the netdev_uses_trailer_tags function. */
+#undef HAVE_NETDEV_USES_TRAILER_TAGS
+
 /* Define if netif_receive_skb takes 3 arguments. */
 #undef HAVE_NETIF_RECEIVE_SKB_EXTENDED
 

configure

@@ -10625,6 +10625,74 @@ $as_echo "#define HAVE_NETDEV_GET_TX_QUEUE 1" >>confdefs.h
 
     fi
 
+    ac_fn_c_check_decl "$LINENO" "netdev_uses_dsa_tags" "ac_cv_have_decl_netdev_uses_dsa_tags" "#if HAVE_LINUXMODULE_2_6
+# define KBUILD_STR(s)		#s
+# define KBUILD_BASENAME	KBUILD_STR(click)
+# define KBUILD_MODNAME		KBUILD_STR(click)
+#endif
+#define new linux_new
+#define this linux_this
+#define delete linux_delete
+#define class linux_class
+#define virtual linux_virtual
+#define typename linux_typename
+#define private linux_private
+#define protected linux_protected
+#define public linux_public
+#define namespace linux_namespace
+#define false linux_false
+#define true linux_true
+#include <linux/autoconf.h>
+#include <asm/types.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+"
+if test "x$ac_cv_have_decl_netdev_uses_dsa_tags" = x""yes; then :
+  ac_cv_netdev_uses_dsa_tags=yes
+else
+  ac_cv_netdev_uses_dsa_tags=no
+fi
+
+    if test $ac_cv_netdev_uses_dsa_tags = yes; then
+
+$as_echo "#define HAVE_NETDEV_USES_DSA_TAGS 1" >>confdefs.h
+
+    fi
+
+    ac_fn_c_check_decl "$LINENO" "netdev_uses_trailer_tags" "ac_cv_have_decl_netdev_uses_trailer_tags" "#if HAVE_LINUXMODULE_2_6
+# define KBUILD_STR(s)		#s
+# define KBUILD_BASENAME	KBUILD_STR(click)
+# define KBUILD_MODNAME		KBUILD_STR(click)
+#endif
+#define new linux_new
+#define this linux_this
+#define delete linux_delete
+#define class linux_class
+#define virtual linux_virtual
+#define typename linux_typename
+#define private linux_private
+#define protected linux_protected
+#define public linux_public
+#define namespace linux_namespace
+#define false linux_false
+#define true linux_true
+#include <linux/autoconf.h>
+#include <asm/types.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+"
+if test "x$ac_cv_have_decl_netdev_uses_trailer_tags" = x""yes; then :
+  ac_cv_netdev_uses_trailer_tags=yes
+else
+  ac_cv_netdev_uses_trailer_tags=no
+fi
+
+    if test $ac_cv_netdev_uses_trailer_tags = yes; then
+
+$as_echo "#define HAVE_NETDEV_USES_TRAILER_TAGS 1" >>confdefs.h
+
+    fi
+
 
     CC="$save_cc"
     CXX="$save_cxx"

configure.in

@@ -1297,6 +1297,20 @@ void f1(int64_t) { // will fail if long long and int64_t are the same type
 	AC_DEFINE([HAVE_NETDEV_GET_TX_QUEUE], [1], [Define if you have the netdev_get_tx_queue function.])
     fi
 
+    AC_CHECK_DECL(netdev_uses_dsa_tags, [ac_cv_netdev_uses_dsa_tags=yes], [ac_cv_netdev_uses_dsa_tags=no], [CLICK_LINUXMODULE_PROLOGUE()[
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>]])
+    if test $ac_cv_netdev_uses_dsa_tags = yes; then
+	AC_DEFINE([HAVE_NETDEV_USES_DSA_TAGS], [1], [Define if you have the netdev_uses_dsa_tags function.])
+    fi
+
+    AC_CHECK_DECL(netdev_uses_trailer_tags, [ac_cv_netdev_uses_trailer_tags=yes], [ac_cv_netdev_uses_trailer_tags=no], [CLICK_LINUXMODULE_PROLOGUE()[
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>]])
+    if test $ac_cv_netdev_uses_trailer_tags = yes; then
+	AC_DEFINE([HAVE_NETDEV_USES_TRAILER_TAGS], [1], [Define if you have the netdev_uses_trailer_tags function.])
+    fi
+
 
     CC="$save_cc"
     CXX="$save_cxx"

elements/linuxmodule/tohost.cc

@@ -133,6 +133,38 @@ device_notifier_hook(struct notifier_block *nb, unsigned long flags, void *v)
 }
 }
 
+static inline uint16_t
+tohost_eth_type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+#if 0
+    /* XXX Newer versions of eth_type_trans have this code, but we can't use
+     * it in a module since dsa_uses_dsa_tags is not exported. */
+# if HAVE_NETDEV_USES_DSA_TAGS
+    if (netdev_uses_dsa_tags(skb->dev))
+	return __constant_htons(ETH_P_DSA);
+# endif
+# if HAVE_NETDEV_USES_TRAILER_TAGS
+    if (netdev_uses_trailer_tags(skb->dev))
+	return __constant_htons(ETH_P_TRAILER);
+# endif
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
+    const ethhdr *eth = eth_hdr(skb);
+#else
+    const ethhdr *eth = skb->mac.ethernet;
+#endif
+    if (ntohs(eth->h_proto) >= 1536)
+	return eth->h_proto;
+
+    const unsigned char *rawp = skb->data;
+    /* "This is a magic hack to spot IPX packets."
+     * See net/ethernet/eth.c:eth_type_trans */
+    if (*(const unsigned short *)rawp == 0xFFFF)
+	return __constant_htons(ETH_P_802_3);
+    return __constant_htons(ETH_P_802_2);
+}
+
 void
 ToHost::push(int port, Packet *p)
 {
@@ -157,9 +189,20 @@ ToHost::push(int port, Packet *p)
     skb->pkt_type &= PACKET_TYPE_MASK;
 #endif
 
+    // skb->dst may be set if the packet came from Linux originally. In this
+    // case, we must clear skb->dst so Linux finds the correct dst.
+#if HAVE_SKB_DST_DROP
+    skb_dst_drop(skb);
+#else
+    if (skb->dst) {
+	dst_release(skb->dst);
+	skb->dst = 0;
+    }
+#endif
+
     // MAC header is the data pointer
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
-    skb_set_mac_header(skb, 0);
+    skb_reset_mac_header(skb);
 #else
     skb->mac.raw = skb->data;
 #endif
@@ -169,33 +212,10 @@ ToHost::push(int port, Packet *p)
 	skb->protocol = __constant_htons(ETH_P_IP);
     else {
 	// do not call eth_type_trans; it changes pkt_type! Instead, do its
-	// work directly.
+	// relevant work directly.
 	skb_pull(skb, 14);
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
-	const ethhdr *eth = eth_hdr(skb);
-#else
-	const ethhdr *eth = skb->mac.ethernet;
-#endif
-	if (ntohs(eth->h_proto) >= 1536)
-	    skb->protocol = eth->h_proto;
-	else {
-	    const unsigned short *crap = (const unsigned short *)skb->data;
-	    // "magic hack to spot IPX packets"
-	    skb->protocol = (*crap == 0xFFFF ? htons(ETH_P_802_3) : htons(ETH_P_802_2));
-	}
-    }
-
-    // skb->dst may be set if the packet came from Linux originally. In this
-    // case, we must clear skb->dst so Linux finds the correct dst.
-#if HAVE_SKB_DST_DROP
-    skb_dst_drop(skb);
-#else
-    if (skb->dst) {
-	dst_release(skb->dst);
-	skb->dst = 0;
+	skb->protocol = tohost_eth_type_trans(skb, skb->dev);
     }
-#endif
 
     // get protocol to pass to Linux
     int protocol = (_sniffers ? 0xFFFF : skb->protocol);