[IPV6] MIP6: Several obvious clean-ups.

- Remove redundant code.  Pointed out by Brian Haley <brian.haley@hp.com>.
- Unify code paths with/without CONFIG_IPV6_MIP.
- Use NIP6_FMT for IPv6 address textual presentation.
- Fold long line.  Pointed out by David Miller <davem@davemloft.net>.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/ah6.c

@@ -128,9 +128,7 @@ static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *des
 		off += optlen;
 		len -= optlen;
 	}
-	if (len == 0)
-		return;
-
+	/* Note: ok if len == 0 */
 bad:
 	return;
 }
@@ -175,11 +173,7 @@ static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
 	ipv6_addr_copy(&iph->daddr, &final_addr);
 }
 
-#ifdef CONFIG_IPV6_MIP6
 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
-#else
-static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len)
-#endif
 {
 	union {
 		struct ipv6hdr *iph;
@@ -194,30 +188,12 @@ static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len)
 
 	while (exthdr.raw < end) {
 		switch (nexthdr) {
-#ifdef CONFIG_IPV6_MIP6
-		case NEXTHDR_HOP:
-			if (!zero_out_mutable_opts(exthdr.opth)) {
-				LIMIT_NETDEBUG(
-					KERN_WARNING "overrun %sopts\n",
-					nexthdr == NEXTHDR_HOP ?
-						"hop" : "dest");
-				return -EINVAL;
-			}
-			break;
 		case NEXTHDR_DEST:
+#ifdef CONFIG_IPV6_MIP6
 			if (dir == XFRM_POLICY_OUT)
 				ipv6_rearrange_destopt(iph, exthdr.opth);
-			if (!zero_out_mutable_opts(exthdr.opth)) {
-				LIMIT_NETDEBUG(
-					KERN_WARNING "overrun %sopts\n",
-					nexthdr == NEXTHDR_HOP ?
-						"hop" : "dest");
-				return -EINVAL;
-			}
-			break;
-#else
+#endif
 		case NEXTHDR_HOP:
-		case NEXTHDR_DEST:
 			if (!zero_out_mutable_opts(exthdr.opth)) {
 				LIMIT_NETDEBUG(
 					KERN_WARNING "overrun %sopts\n",
@@ -226,7 +202,6 @@ static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len)
 				return -EINVAL;
 			}
 			break;
-#endif
 
 		case NEXTHDR_ROUTING:
 			ipv6_rearrange_rthdr(iph, exthdr.rth);
@@ -282,16 +257,13 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
 		}
 #ifdef CONFIG_IPV6_MIP6
 		memcpy(tmp_ext, &top_iph->saddr, extlen);
-		err = ipv6_clear_mutable_options(top_iph,
-						 extlen - sizeof(*tmp_ext) +
-						 sizeof(*top_iph),
-						 XFRM_POLICY_OUT);
 #else
 		memcpy(tmp_ext, &top_iph->daddr, extlen);
+#endif
 		err = ipv6_clear_mutable_options(top_iph,
 						 extlen - sizeof(*tmp_ext) +
-						 sizeof(*top_iph));
-#endif
+						 sizeof(*top_iph),
+						 XFRM_POLICY_OUT);
 		if (err)
 			goto error_free_iph;
 	}
@@ -386,13 +358,8 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
 	if (!tmp_hdr)
 		goto out;
 	memcpy(tmp_hdr, skb->nh.raw, hdr_len);
-#ifdef CONFIG_IPV6_MIP6
 	if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len, XFRM_POLICY_IN))
 		goto free_out;
-#else
-	if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len))
-		goto free_out;
-#endif
 	skb->nh.ipv6h->priority    = 0;
 	skb->nh.ipv6h->flow_lbl[0] = 0;
 	skb->nh.ipv6h->flow_lbl[1] = 0;

net/ipv6/exthdrs.c

@@ -87,7 +87,6 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 		len -= optlen;
 	}
 	/* not_found */
-	return -1;
  bad:
 	return -1;
 }

net/ipv6/mip6.c

@@ -121,7 +121,8 @@ int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
 				    &skb->nh.ipv6h->daddr,
 				    mhlen, IPPROTO_MH,
 				    skb_checksum(skb, 0, mhlen, 0))) {
-			LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH checksum failed [%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x > %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x]\n",
+			LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH checksum failed "
+				       "[" NIP6_FMT " > " NIP6_FMT "]\n",
 				       NIP6(skb->nh.ipv6h->saddr),
 				       NIP6(skb->nh.ipv6h->daddr));
 			return -1;
@@ -234,7 +235,8 @@ static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct
 	struct timeval stamp;
 	int err = 0;
 
-	if (unlikely(fl->proto == IPPROTO_MH && fl->fl_mh_type <= IP6_MH_TYPE_MAX))
+	if (unlikely(fl->proto == IPPROTO_MH &&
+		     fl->fl_mh_type <= IP6_MH_TYPE_MAX))
 		goto out;
 
 	if (likely(opt->dsthao)) {