In ip receive path, when ip header hasn't been pulled yet, ip_hdr() and
skb->data are pointing to the same byte.
In ip output path, when ip header is just pushed, ip_hdr() and skb->data
are pointing to the same byte.
As ip_hdr() is more expensive than using skb->data, so replace ip_hdr()
with skb->data in these situations for optimization.
Signed-off-by: Yafang Shao <laoar.s...@gmail.com>
---
net/ipv4/ip_input.c | 8 ++++----
net/ipv4/ip_output.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 7582713..7a03e8c 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -309,7 +309,7 @@ static inline bool ip_rcv_options(struct sk_buff *skb)
static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
- const struct iphdr *iph = ip_hdr(skb);
+ const struct iphdr *iph = (const struct iphdr *)skb->data;
int (*edemux)(struct sk_buff *skb);
struct net_device *dev = skb->dev;
struct rtable *rt;
@@ -335,7 +335,7 @@ static int ip_rcv_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
if (unlikely(err))
goto drop_error;
/* must reload iph, skb->head might have changed */
- iph = ip_hdr(skb);
+ iph = (const struct iphdr *)skb->data;
}
}
@@ -433,7 +433,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt,
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto inhdr_error;
- iph = ip_hdr(skb);
+ iph = (const struct iphdr *)skb->data;
/*
* RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails
the checksum.
@@ -459,7 +459,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt,
if (!pskb_may_pull(skb, iph->ihl*4))
goto inhdr_error;
- iph = ip_hdr(skb);
+ iph = (const struct iphdr *)skb->data;
if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
goto csum_error;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index af5a830..f5014cd 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -96,7 +96,7 @@ void ip_send_check(struct iphdr *iph)
int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
- struct iphdr *iph = ip_hdr(skb);
+ struct iphdr *iph = (struct iphdr *)skb->data;
iph->tot_len = htons(skb->len);
ip_send_check(iph);
@@ -151,7 +151,7 @@ int ip_build_and_send_pkt(struct sk_buff *skb, const struct
sock *sk,
/* Build the IP header. */
skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
skb_reset_network_header(skb);
- iph = ip_hdr(skb);
+ iph = (struct iphdr *)skb->data;
iph->version = 4;
iph->ihl = 5;
iph->tos = inet->tos;
@@ -477,7 +477,7 @@ int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
struct flowi *fl)
/* OK, we know where to send it, allocate and build IP header. */
skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen :
0));
skb_reset_network_header(skb);
- iph = ip_hdr(skb);
+ iph = (struct iphdr *)skb->data;
*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df)
iph->frag_off = htons(IP_DF);
@@ -659,7 +659,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct
sk_buff *skb,
__skb_push(frag, hlen);
skb_reset_network_header(frag);
memcpy(skb_network_header(frag), iph, hlen);
- iph = ip_hdr(frag);
+ iph = (struct iphdr *)skb->data;
iph->tot_len = htons(frag->len);
ip_copy_metadata(frag, skb);
if (offset == 0)
--
1.8.3.1
