net-next: add dev_loopback_xmit() to avoid duplicate code

PATCH Applied Michel Machado 2 participants 2 messages Jun 12, 2012 – Jun 13, 2012

Subsystems (3)

Networking Network drivers IPv4/IPv6

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Michel Machado

author

2012-06-12 20:16 UTC #0 lore raw

PATCH 1/1 net-next: add dev_loopback_xmit() to avoid duplicate code

Add dev_loopback_xmit() in order to deduplicate functions ip_dev_loopback_xmit() (in net/ipv4/ip_output.c) and ip6_dev_loopback_xmit() (in net/ipv6/ip6_output.c).

I was about to reinvent the wheel when I noticed that ip_dev_loopback_xmit() and ip6_dev_loopback_xmit() do exactly what I need and are not IP-only functions, but they were not available to reuse elsewhere.

ip6_dev_loopback_xmit() does not have line "skb_dst_force(skb);", but I understand that this is harmless, and should be in dev_loopback_xmit().

Signed-off-by Michel Machado <[email protected]>

CC "David S. Miller" <[email protected]>

CC Alexey Kuznetsov <[email protected]>

CC James Morris <[email protected]>

CC Hideaki YOSHIFUJI <[email protected]>

CC Patrick McHardy <[email protected]>

CC Eric Dumazet <[email protected]>

CC Jiri Pirko <[email protected]>

CC "Michał Mirosław" <[email protected]>

CC Ben Hutchings <[email protected]>

---

include/linux/netdevice.h +1 -0

index e7fd468..1c49c21 100644
@@ -1626,6 +1626,7 @@ extern int		dev_alloc_name(struct net_device *dev, const char *name);
 extern int		dev_open(struct net_device *dev);
 extern int		dev_close(struct net_device *dev);
 extern void		dev_disable_lro(struct net_device *dev);
+extern int		dev_loopback_xmit(struct sk_buff *newskb);
 extern int		dev_queue_xmit(struct sk_buff *skb);
 extern int		register_netdevice(struct net_device *dev);
 extern void		unregister_netdevice_queue(struct net_device *dev,

net/core/dev.c +17 -0

index cd09819..c6e29ea6 100644
@@ -2476,6 +2476,23 @@ static DEFINE_PER_CPU(int, xmit_recursion);
 #define RECURSION_LIMIT 10
 
 /**
+ *	dev_loopback_xmit - loop back @skb
+ *	@skb: buffer to transmit
+ */
+int dev_loopback_xmit(struct sk_buff *skb)
+{
+	skb_reset_mac_header(skb);
+	__skb_pull(skb, skb_network_offset(skb));
+	skb->pkt_type = PACKET_LOOPBACK;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	WARN_ON(!skb_dst(skb));
+	skb_dst_force(skb);
+	netif_rx_ni(skb);
+	return 0;
+}
+EXPORT_SYMBOL(dev_loopback_xmit);
+
+/**
  *	dev_queue_xmit - transmit a buffer
  *	@skb: buffer to transmit
  *

net/ipv4/ip_output.c +2 ~~-15~~

index 451f97c..d34ddde 100644
@@ -113,19 +113,6 @@ int ip_local_out(struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(ip_local_out);
 
-/* dev_loopback_xmit for use with netfilter. */
-static int ip_dev_loopback_xmit(struct sk_buff *newskb)
-{
-	skb_reset_mac_header(newskb);
-	__skb_pull(newskb, skb_network_offset(newskb));
-	newskb->pkt_type = PACKET_LOOPBACK;
-	newskb->ip_summed = CHECKSUM_UNNECESSARY;
-	WARN_ON(!skb_dst(newskb));
-	skb_dst_force(newskb);
-	netif_rx_ni(newskb);
-	return 0;
-}
-
 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
 {
 	int ttl = inet->uc_ttl;

@@ -281,7 +268,7 @@ int ip_mc_output(struct sk_buff *skb)
 			if (newskb)
 				NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
 					newskb, NULL, newskb->dev,
-					ip_dev_loopback_xmit);
+					dev_loopback_xmit);
 		}
 
 		/* Multicasts with ttl 0 must not go beyond the host */

@@ -296,7 +283,7 @@ int ip_mc_output(struct sk_buff *skb)
 		struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
 		if (newskb)
 			NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb,
-				NULL, newskb->dev, ip_dev_loopback_xmit);
+				NULL, newskb->dev, dev_loopback_xmit);
 	}
 
 	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL,

net/ipv6/ip6_output.c +1 ~~-14~~

index d99fdc6..8443c00 100644
@@ -83,19 +83,6 @@ int ip6_local_out(struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(ip6_local_out);
 
-/* dev_loopback_xmit for use with netfilter. */
-static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
-{
-	skb_reset_mac_header(newskb);
-	__skb_pull(newskb, skb_network_offset(newskb));
-	newskb->pkt_type = PACKET_LOOPBACK;
-	newskb->ip_summed = CHECKSUM_UNNECESSARY;
-	WARN_ON(!skb_dst(newskb));
-
-	netif_rx_ni(newskb);
-	return 0;
-}
-
 static int ip6_finish_output2(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);

@@ -121,7 +108,7 @@ static int ip6_finish_output2(struct sk_buff *skb)
 			if (newskb)
 				NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
 					newskb, NULL, newskb->dev,
-					ip6_dev_loopback_xmit);
+					dev_loopback_xmit);
 
 			if (ipv6_hdr(skb)->hop_limit == 0) {
 				IP6_INC_STATS(dev_net(dev), idev,

David Miller

maintainer Applied

2012-06-13 01:52 UTC #1 lore raw

From: Michel Machado <[email protected]>
Date: Tue, 12 Jun 2012 16:16:35 -0400

Quoted 9 lines

Add dev_loopback_xmit() in order to deduplicate functions ip_dev_loopback_xmit() (in net/ipv4/ip_output.c) and ip6_dev_loopback_xmit() (in net/ipv6/ip6_output.c).
I was about to reinvent the wheel when I noticed that ip_dev_loopback_xmit() and ip6_dev_loopback_xmit() do exactly what I need and are not IP-only functions, but they were not available to reuse elsewhere.

Quoted 4 lines

ip6_dev_loopback_xmit() does not have line "skb_dst_force(skb);", but I understand that this is harmless, and should be in dev_loopback_xmit().
Signed-off-by Michel Machado <[email protected]>

Applied.