Merge branch 'ipv6_ndisc'

YOSHIFUJI Hideaki says:

====================
This series of changes basically clean up NDISC logic,
especially on sender side.

We originally do For NS/NA/RS:
 1) build temporary ICMPv6 header
 2) ndisc_build_skb() with temporary ICMPv6 header and rather
    criptic arguments.
    - Calculate total length and allocate sk_buff
    - Build IPv6 header.
    - copy ICMPv6 header, additional data and ND options.
    - Fill-in ICMPv6 checksum.
    Here, structures defined for message format was not used
    at all, it is difficult to understand what is being sent,
    and it was not generic.
 3) __ndisc_send()
    - Allocate temporary dst.
    - Send it.

Several issues:
- We could not defer decision if we should/can send some ND
  option.
- It is hard to see the packet format at a glance.
- ICMPv6 header was built as temporary variable, and then
  copied to the buffer.
- Some code path for Redirect was not shared.

With these patches, we do:
 1) Calculate (or estimate) message length and option length.
 2) Allocate skb (via new ndisc_skb_alloc()).
 3) Fill-in ICMPv6 message directly using compound literals.
 4) Fill-in ICMPv6 checksum
 5) Build IPv6 header (including length)
 6) Send the packet (via ndisc_send_skb()).
    - allocate temporary dst and send it.

- We can defer calculating real length of the packet.
  For example, we can give up filling some option at when
  filling in.
- Message is built directly without temporary buffer.
- Structures defined for message format is easier to understand
  what is being built.
- NS/NA/RS/Redirect share same logic.
- Reduced code/data size:
	   text	   data	    bss	    dec	    hex	filename
	 265407	  14133	   3488	 283028	  45194	old/net/ipv6/ipv6.o
	 264955	  14109	   3488	 282552	  44fb8	new/net/ipv6/ipv6.o
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 7 insertions, 8 deletions

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 464c6f70eca1..c1878f7049c8 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -661,13 +661,6 @@ extern int			ip6_xmit(struct sock *sk,
 					 struct ipv6_txoptions *opt,
 					 int tclass);
 
-extern int			ip6_nd_hdr(struct sock *sk,
-					   struct sk_buff *skb,
-					   struct net_device *dev,
-					   const struct in6_addr *saddr,
-					   const struct in6_addr *daddr,
-					   int proto, int len);
-
 extern int			ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr);
 
 extern int			ip6_append_data(struct sock *sk,
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index ec48f42db5ed..745bf741e029 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -127,13 +127,19 @@ static int ndisc_addr_option_pad(unsigned short type)
 	}
 }
 
+static inline int ndisc_opt_addr_space(struct net_device *dev)
+{
+	return NDISC_OPT_SPACE(dev->addr_len +
+			       ndisc_addr_option_pad(dev->type));
+}
+
 static inline u8 *ndisc_opt_addr_data(struct nd_opt_hdr *p,
 				      struct net_device *dev)
 {
 	u8 *lladdr = (u8 *)(p + 1);
 	int lladdrlen = p->nd_opt_len << 3;
 	int prepad = ndisc_addr_option_pad(dev->type);
-	if (lladdrlen != NDISC_OPT_SPACE(dev->addr_len + prepad))
+	if (lladdrlen != ndisc_opt_addr_space(dev))
 		return NULL;
 	return lladdr + prepad;
 }