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/*
* replication.c : packet replication
*
* Copyright (c) 2013 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vppinfra/error.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/replication.h>
replication_main_t replication_main;
replication_context_t *
replication_prep (vlib_main_t * vm,
vlib_buffer_t * b0,
u32 recycle_node_index,
u32 l2_packet)
{
replication_main_t * rm = &replication_main;
replication_context_t * ctx;
uword cpu_number = vm->cpu_index;
ip4_header_t * ip;
u32 ctx_id;
// Allocate a context, reserve context 0
if (PREDICT_FALSE(rm->contexts[cpu_number] == 0))
pool_get_aligned (rm->contexts[cpu_number], ctx, CLIB_CACHE_LINE_BYTES);
pool_get_aligned (rm->contexts[cpu_number], ctx, CLIB_CACHE_LINE_BYTES);
ctx_id = ctx - rm->contexts[cpu_number];
// Save state from vlib buffer
ctx->saved_free_list_index = b0->free_list_index;
ctx->current_data = b0->current_data;
// Set up vlib buffer hooks
b0->recycle_count = ctx_id;
b0->free_list_index = rm->recycle_list_index;
b0->flags |= VLIB_BUFFER_RECYCLE;
// Save feature state
ctx->recycle_node_index = recycle_node_index;
// Save vnet state
clib_memcpy (ctx->vnet_buffer, vnet_buffer(b0), sizeof(vnet_buffer_opaque_t));
// Save packet contents
ctx->l2_packet = l2_packet;
ip = (ip4_header_t *)vlib_buffer_get_current (b0);
if (l2_packet) {
// Save ethernet header
ctx->l2_header[0] = ((u64 *)ip)[0];
ctx->l2_header[1] = ((u64 *)ip)[1];
ctx->l2_header[2] = ((u64 *)ip)[2];
// set ip to the true ip header
ip = (ip4_header_t *)(((u8 *)ip) + vnet_buffer(b0)->l2.l2_len);
}
// Copy L3 fields.
// We need to save TOS for ip4 and ip6 packets. Fortunately the TOS field is
// in the first two bytes of both the ip4 and ip6 headers.
ctx->ip_tos = *((u16 *)(ip));
// Save the ip4 checksum as well. We just blindly save the corresponding two
// bytes even for ip6 packets.
ctx->ip4_checksum = ip->checksum;
return ctx;
}
replication_context_t *
replication_recycle (vlib_main_t * vm,
vlib_buffer_t * b0,
u32 is_last)
{
replication_main_t * rm = &replication_main;
replication_context_t * ctx;
uword cpu_number = vm->cpu_index;
ip4_header_t * ip;
// Get access to the replication context
ctx = pool_elt_at_index (rm->contexts[cpu_number], b0->recycle_count);
// Restore vnet buffer state
clib_memcpy (vnet_buffer(b0), ctx->vnet_buffer, sizeof(vnet_buffer_opaque_t));
// Restore the packet start (current_data) and length
vlib_buffer_advance(b0, ctx->current_data - b0->current_data);
// Restore packet contents
ip = (ip4_header_t *)vlib_buffer_get_current (b0);
if (ctx->l2_packet) {
// Restore ethernet header
((u64 *)ip)[0] = ctx->l2_header[0];
((u64 *)ip)[1] = ctx->l2_header[1];
((u64 *)ip)[2] = ctx->l2_header[2];
// set ip to the true ip header
ip = (ip4_header_t *)(((u8 *)ip) + vnet_buffer(b0)->l2.l2_len);
}
// Restore L3 fields
*((u16 *)(ip)) = ctx->ip_tos;
ip->checksum = ctx->ip4_checksum;
if (is_last) {
// This is the last replication in the list.
// Restore original buffer free functionality.
b0->free_list_index = ctx->saved_free_list_index;
// Free context back to its pool
pool_put (rm->contexts[cpu_number], ctx);
}
return ctx;
}
/*
* fish pkts back from the recycle queue/freelist
* un-flatten the context chains
*/
static void replication_recycle_callback (vlib_main_t *vm,
vlib_buffer_free_list_t * fl)
{
vlib_frame_t * f = 0;
u32 n_left_from;
u32 n_left_to_next = 0;
u32 n_this_frame = 0;
u32 * from;
u32 * to_next = 0;
u32 bi0, pi0;
vlib_buffer_t *b0;
int i;
replication_main_t * rm = &replication_main;
replication_context_t * ctx;
u32 feature_node_index = 0;
uword cpu_number = vm->cpu_index;
// All buffers in the list are destined to the same recycle node.
// Pull the recycle node index from the first buffer.
// Note: this could be sped up if the node index were stuffed into
// the freelist itself.
if (vec_len (fl->aligned_buffers) > 0) {
bi0 = fl->aligned_buffers[0];
b0 = vlib_get_buffer (vm, bi0);
ctx = pool_elt_at_index (rm->contexts[cpu_number],
b0->recycle_count);
feature_node_index = ctx->recycle_node_index;
} else if (vec_len (fl->unaligned_buffers) > 0) {
bi0 = fl->unaligned_buffers[0];
b0 = vlib_get_buffer (vm, bi0);
ctx = pool_elt_at_index (rm->contexts[cpu_number], b0->recycle_count);
feature_node_index = ctx->recycle_node_index;
}
/* aligned, unaligned buffers */
for (i = 0; i < 2; i++)
{
if (i == 0)
{
from = fl->aligned_buffers;
n_left_from = vec_len (from);
}
else
{
from = fl->unaligned_buffers;
n_left_from = vec_len (from);
}
while (n_left_from > 0)
{
if (PREDICT_FALSE(n_left_to_next == 0))
{
if (f)
{
f->n_vectors = n_this_frame;
vlib_put_frame_to_node (vm, feature_node_index, f);
}
f = vlib_get_frame_to_node (vm, feature_node_index);
to_next = vlib_frame_vector_args (f);
n_left_to_next = VLIB_FRAME_SIZE;
n_this_frame = 0;
}
bi0 = from[0];
if (PREDICT_TRUE(n_left_from > 1))
{
pi0 = from[1];
vlib_prefetch_buffer_with_index(vm,pi0,LOAD);
}
b0 = vlib_get_buffer (vm, bi0);
// Mark that this buffer was just recycled
b0->flags |= VLIB_BUFFER_IS_RECYCLED;
// If buffer is traced, mark frame as traced
if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
f->flags |= VLIB_FRAME_TRACE;
to_next[0] = bi0;
from++;
to_next++;
n_this_frame++;
n_left_to_next--;
n_left_from--;
}
}
vec_reset_length (fl->aligned_buffers);
vec_reset_length (fl->unaligned_buffers);
if (f)
{
ASSERT(n_this_frame);
f->n_vectors = n_this_frame;
vlib_put_frame_to_node (vm, feature_node_index, f);
}
}
clib_error_t *replication_init (vlib_main_t *vm)
{
replication_main_t * rm = &replication_main;
vlib_buffer_main_t * bm = vm->buffer_main;
vlib_buffer_free_list_t * fl;
__attribute__((unused)) replication_context_t * ctx;
vlib_thread_main_t * tm = vlib_get_thread_main();
rm->vlib_main = vm;
rm->vnet_main = vnet_get_main();
rm->recycle_list_index =
vlib_buffer_create_free_list (vm, 1024 /* fictional */,
"replication-recycle");
fl = pool_elt_at_index (bm->buffer_free_list_pool,
rm->recycle_list_index);
fl->buffers_added_to_freelist_function = replication_recycle_callback;
// Verify the replication context is the expected size
ASSERT(sizeof(replication_context_t) == 128); // 2 cache lines
vec_validate (rm->contexts, tm->n_vlib_mains - 1);
return 0;
}
VLIB_INIT_FUNCTION (replication_init);
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