ip6_tunnel - endianness annotations

Convert rel_info to host-endian before calling ip6_tnl_err().
The things become much more straightforward that way.
The key observation (and the reason why that code actually
worked) is that after ip6_tnl_err() we either immediately
bailed out or had rel_info set to 0 or had it set to host-endian
and guaranteed to hit
(rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED)
case.  So inconsistent endianness didn't really lead to bugs,
but it had been subtle and prone to breakage.  New variant is
saner and obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index df30976f6dfd196c7f40511356131c1f9a11c09a..ca774d8e3be35e09c010db9aae493e7db6be997f 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -385,7 +385,7 @@ parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw)
 
 static int
 ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
-           int *type, int *code, int *msg, __be32 *info, int offset)
+           int *type, int *code, int *msg, __u32 *info, int offset)
 {
        struct ipv6hdr *ipv6h = (struct ipv6hdr *) skb->data;
        struct ip6_tnl *t;
@@ -435,7 +435,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
                if ((*code) == ICMPV6_HDR_FIELD)
                        teli = parse_tlv_tnl_enc_lim(skb, skb->data);
 
-               if (teli && teli == ntohl(*info) - 2) {
+               if (teli && teli == *info - 2) {
                        tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
                        if (tel->encap_limit == 0) {
                                if (net_ratelimit())
@@ -452,7 +452,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
                }
                break;
        case ICMPV6_PKT_TOOBIG:
-               mtu = ntohl(*info) - offset;
+               mtu = *info - offset;
                if (mtu < IPV6_MIN_MTU)
                        mtu = IPV6_MIN_MTU;
                t->dev->mtu = mtu;
@@ -478,12 +478,12 @@ out:
 
 static int
 ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
-          int type, int code, int offset, __u32 info)
+          int type, int code, int offset, __be32 info)
 {
        int rel_msg = 0;
        int rel_type = type;
        int rel_code = code;
-       __u32 rel_info = info;
+       __u32 rel_info = ntohl(info);
        int err;
        struct sk_buff *skb2;
        struct iphdr *eiph;
@@ -564,10 +564,9 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                        goto out;
 
                skb2->dst->ops->update_pmtu(skb2->dst, rel_info);
-               rel_info = htonl(rel_info);
        }
 
-       icmp_send(skb2, rel_type, rel_code, rel_info);
+       icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
 
 out:
        kfree_skb(skb2);
@@ -576,12 +575,12 @@ out:
 
 static int
 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
-          int type, int code, int offset, __u32 info)
+          int type, int code, int offset, __be32 info)
 {
        int rel_msg = 0;
        int rel_type = type;
        int rel_code = code;
-       __u32 rel_info = info;
+       __u32 rel_info = ntohl(info);
        int err;
 
        err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,