tcp: custom checksum calculations for Ipv4/Ipv6
Type: feature
Based on the configuration, we can disable checksum offload capability
and calculate checksum while pushing the TCP & IP header.
This saves some cycles when VPP stack is used in legacy hardware devices.
Signed-off-by: Srikanth A <srakula@cisco.com>
Change-Id: Ic1b3fcf3040917e47ee65263694ebf7437ac5668
(cherry picked from commit 3642782a2748503f5b5ccf89d1575c1d489948ef)
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index d4717c6..40c396c 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -1303,10 +1303,6 @@
{
ip_csum_t sum0;
u32 ip_header_length, payload_length_host_byte_order;
- u32 n_this_buffer, n_bytes_left, n_ip_bytes_this_buffer;
- u16 sum16;
- u8 *data_this_buffer;
- u8 length_odd;
/* Initialize checksum with ip header. */
ip_header_length = ip4_header_bytes (ip0);
@@ -1329,45 +1325,9 @@
sum0 =
ip_csum_with_carry (sum0, clib_mem_unaligned (&ip0->src_address, u64));
- n_bytes_left = n_this_buffer = payload_length_host_byte_order;
- data_this_buffer = (u8 *) ip0 + ip_header_length;
- n_ip_bytes_this_buffer =
- p0->current_length - (((u8 *) ip0 - p0->data) - p0->current_data);
- if (n_this_buffer + ip_header_length > n_ip_bytes_this_buffer)
- {
- n_this_buffer = n_ip_bytes_this_buffer > ip_header_length ?
- n_ip_bytes_this_buffer - ip_header_length : 0;
- }
-
- while (1)
- {
- sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
- n_bytes_left -= n_this_buffer;
- if (n_bytes_left == 0)
- break;
-
- ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT);
- if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
- return 0xfefe;
-
- length_odd = (n_this_buffer & 1);
-
- p0 = vlib_get_buffer (vm, p0->next_buffer);
- data_this_buffer = vlib_buffer_get_current (p0);
- n_this_buffer = clib_min (p0->current_length, n_bytes_left);
-
- if (PREDICT_FALSE (length_odd))
- {
- /* Prepend a 0 or the resulting checksum will be incorrect. */
- data_this_buffer--;
- n_this_buffer++;
- n_bytes_left++;
- data_this_buffer[0] = 0;
- }
- }
-
- sum16 = ~ip_csum_fold (sum0);
- return sum16;
+ return ip_calculate_l4_checksum (vm, p0, sum0,
+ payload_length_host_byte_order, (u8 *) ip0,
+ ip_header_length, NULL);
}
u32