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ipv4: defer fib_compute_spec_dst() call

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ip_options_compile() can avoid calling fib_compute_spec_dst()
by default, and perform the call only if needed.

David suggested to add a helper to make the call only once.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-07-04 22:30:09 +00:00 committed by David S. Miller
parent 36bdbcae2f
commit bf5e53e371
1 changed files with 12 additions and 3 deletions
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15
net/ipv4/ip_options.c
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@ -242,6 +242,15 @@ void ip_options_fragment(struct sk_buff *skb)
opt->ts_needtime = 0;
}
/* helper used by ip_options_compile() to call fib_compute_spec_dst()
* at most one time.
*/
static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
{
if (*spec_dst == htonl(INADDR_ANY))
*spec_dst = fib_compute_spec_dst(skb);
}
/*
* Verify options and fill pointers in struct options.
* Caller should clear *opt, and set opt->data.
@ -251,7 +260,7 @@ void ip_options_fragment(struct sk_buff *skb)
int ip_options_compile(struct net *net,
struct ip_options *opt, struct sk_buff *skb)
{
__be32 spec_dst = (__force __be32) 0;
__be32 spec_dst = htonl(INADDR_ANY);
unsigned char *pp_ptr = NULL;
struct rtable *rt = NULL;
unsigned char *optptr;
@ -260,8 +269,6 @@ int ip_options_compile(struct net *net,
if (skb != NULL) {
rt = skb_rtable(skb);
if (rt)
spec_dst = fib_compute_spec_dst(skb);
optptr = (unsigned char *)&(ip_hdr(skb)[1]);
} else
optptr = opt->__data;
@ -334,6 +341,7 @@ int ip_options_compile(struct net *net,
goto error;
}
if (rt) {
spec_dst_fill(&spec_dst, skb);
memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
opt->is_changed = 1;
}
@ -376,6 +384,7 @@ int ip_options_compile(struct net *net,
}
opt->ts = optptr - iph;
if (rt) {
spec_dst_fill(&spec_dst, skb);
memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
timeptr = &optptr[optptr[2]+3];
}