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ip: improve ip4_header_checksum_is_valid

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It is cheaper to include checksum field in calculation and simply
compare result with zero.

Type: improvement

Change-Id: I6f77632c0a4d2f2c632d044d3a5d2fcf2b5bac62
Signed-off-by: Damjan Marion <damarion@cisco.com>
This commit is contained in:
Damjan Marion
2020-08-31 19:54:19 +02:00
committed by Benoît Ganne
parent edc816355a
commit 9a79a1ab93
1 changed files with 12 additions and 5 deletions
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17
src/vnet/ip/ip4_packet.h
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@@ -205,8 +205,8 @@ ip4_next_header (ip4_header_t * i)
WARN_OFF(array-bounds)
/* *INDENT-ON* */
always_inline u16
ip4_header_checksum (ip4_header_t * i)
static_always_inline u16
ip4_header_checksum_inline (ip4_header_t * i, int with_checksum)
{
int option_len = (i->ip_version_and_header_length & 0xf) - 5;
uword sum = 0;
@@ -215,7 +215,7 @@ ip4_header_checksum (ip4_header_t * i)
sum += iphdr[0];
sum += iphdr[1];
sum += *(u16 *) (iphdr + 2);
sum += with_checksum ? iphdr[2] : *(u16 *) (iphdr + 2);
/* skip checksum */
sum += iphdr[3];
sum += iphdr[4];
@@ -256,7 +256,8 @@ ip4_header_checksum (ip4_header_t * i)
sum += iphdr[2];
sum += iphdr[3];
sum += iphdr[4];
/* skip checksum */
if (with_checksum)
sum += iphdr[5];
sum += iphdr[6];
sum += iphdr[7];
sum += iphdr[8];
@@ -309,6 +310,12 @@ ip4_header_checksum (ip4_header_t * i)
WARN_ON(array-bounds)
/* *INDENT-ON* */
always_inline u16
ip4_header_checksum (ip4_header_t * i)
{
return ip4_header_checksum_inline (i, /* with_checksum */ 0);
}
always_inline void
ip4_header_set_dscp (ip4_header_t * ip4, ip_dscp_t dscp)
{
@@ -376,7 +383,7 @@ ip4_header_get_df (const ip4_header_t * ip4)
static inline uword
ip4_header_checksum_is_valid (ip4_header_t * i)
{
return i->checksum == ip4_header_checksum (i);
return ip4_header_checksum_inline (i, /* with_checksum */ 1) == 0;
}
#define ip4_partial_header_checksum_x1(ip0,sum0) \