/*
* DHCP feature; applied as an input feature to select DHCP packets
*
* 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 <vnet/dhcp/client.h>
#include <vnet/udp/udp.h>
#define foreach_dhcp_client_detect \
_(EXTRACT, "Extract")
typedef enum
{
#define _(sym,str) DHCP_CLIENT_DETECT_ERROR_##sym,
foreach_dhcp_client_detect
#undef _
DHCP_CLIENT_DETECT_N_ERROR,
} dhcp_client_detect_error_t;
static char *dhcp_client_detect_error_strings[] = {
#define _(sym,string) string,
foreach_dhcp_client_detect
#undef _
};
typedef enum
{
#define _(sym,str) DHCP_CLIENT_DETECT_NEXT_##sym,
foreach_dhcp_client_detect
#undef _
DHCP_CLIENT_DETECT_N_NEXT,
} dhcp_client_detect_next_t;
/**
* per-packet trace data
*/
typedef struct dhcp_client_detect_trace_t_
{
/* per-pkt trace data */
u8 extracted;
} dhcp_client_detect_trace_t;
static uword
dhcp_client_detect_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * frame)
{
dhcp_client_detect_next_t next_index;
u16 dhcp_client_port_network_order;
u32 n_left_from, *from, *to_next;
u32 extractions;
dhcp_client_port_network_order =
clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_client);
next_index = 0;
extractions = 0;
n_left_from = frame->n_vectors;
from = vlib_frame_vector_args (frame);
while (n_left_from > 0)
{
u32 n_left_to_next;
vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
/*
* This loop is optimised not so we can really quickly process DHCp
* offers... but so we can quickly sift them out when the interface
* is also receving 'normal' packets
*/
while (n_left_from >= 8 && n_left_to_next >= 4)
{
udp_header_t *udp0, *udp1, *udp2, *udp3;
ip4_header_t *ip0, *ip1, *ip2, *ip3;
vlib_buffer_t *b0, *b1, *b2, *b3;
u32 next0, next1, next2, next3;
u32 bi0, bi1, bi2, bi3;
next0 = next1 = next2 = next3 = ~0;
bi0 = to_next[0] = from[0];
bi1 = to_next[1] = from[1];
bi2 = to_next[2] = from[2];
bi3 = to_next[3] = from[3];
/* Prefetch next iteration. */
{
vlib_buffer_t *p2, *p3, *p4, *p5;
p2 = vlib_get_buffer (vm, from[2]);
p3 = vlib_get_buffer (vm, from[3]);
p4 = vlib_get_buffer (vm, from[4]);
p5 = vlib_get_buffer (vm, from[5]);
vlib_prefetch_buffer_header (p2, STORE);
vlib_prefetch_buffer_header (p3, STORE);
vlib_prefetch_buffer_header (p4, STORE);
vlib_prefetch_buffer_header (p5, STORE);
CLIB_PREFETCH (p2->data, sizeof (ip0[0]) + sizeof (udp0[0]),
STORE);
CLIB_PREFETCH (p3->data, sizeof (ip0[0]) + sizeof (udp0[0]),
STORE);
CLIB_PREFETCH (p4->data, sizeof (ip0[0]) + sizeof (udp0[0]),
STORE);
CLIB_PREFETCH (p5->data, sizeof (ip0[0]) + sizeof (udp0[0]),
STORE);
}
from += 4;
to_next += 4;
n_left_from -= 4;
n_left_to_next -= 4;
b0 = vlib_get_buffer (vm, bi0);
b1 = vlib_get_buffer (vm, bi1);
b2 = vlib_get_buffer (vm, bi2);
b3 = vlib_get_buffer (vm, bi3);
ip0 = vlib_buffer_get_current (b0);
ip1 = vlib_buffer_get_current (b1);
ip2 = vlib_buffer_get_current (b2);
ip3 = vlib_buffer_get_current (b2);
vnet_feature_next (&next0, b0);
vnet_feature_next (&next1, b1);
vnet_feature_next (&next2, b2);
vnet_feature_next (&next3, b3);
if (ip0->protocol == IP_PROTOCOL_UDP)
{
udp0 = (udp_header_t *) (ip0 + 1);
if (dhcp_client_port_network_order == udp0->dst_port)
{
next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
extractions++;
}
}
if (ip1->protocol == IP_PROTOCOL_UDP)
{
udp1 = (udp_header_t *) (ip1 + 1);
if (dhcp_client_port_network_order == udp1->dst_port)
{
next1 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
extractions++;
}
}
if (ip2->protocol == IP_PROTOCOL_UDP)
{
udp2 = (udp_header_t *) (ip2 + 1);
if (dhcp_client_port_network_order == udp2->dst_port)
{
next2 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
extractions++;
}
}
if (ip3->protocol == IP_PROTOCOL_UDP)
{
udp3 = (udp_header_t *) (ip3 + 1);
if (dhcp_client_port_network_order == udp3->dst_port)
{
next3 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
extractions++;
}
}
if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
{
dhcp_client_detect_trace_t *t =
vlib_add_trace (vm, node, b0, sizeof (*t));
t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
}
if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
{
dhcp_client_detect_trace_t *t =
vlib_add_trace (vm, node, b1, sizeof (*t));
t->extracted = (next1 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
}
if (PREDICT_FALSE (b2->flags & VLIB_BUFFER_IS_TRACED))
{
dhcp_client_detect_trace_t *t =
vlib_add_trace (vm, node, b2, sizeof (*t));
t->extracted = (next2 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
}
if (PREDICT_FALSE (b3->flags & VLIB_BUFFER_IS_TRACED))
{
dhcp_client_detect_trace_t *t =
vlib_add_trace (vm, node, b3, sizeof (*t));
t->extracted = (next3 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
}
/* verify speculative enqueue, maybe switch current next frame */
vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
to_next, n_left_to_next,
bi0, bi1, bi2, bi3,
next0, next1, next2, next3);
}
while (n_left_from > 0 && n_left_to_next > 0)
{
udp_header_t *udp0;
vlib_buffer_t *b0;
ip4_header_t *ip0;
u32 next0 = ~0;
u32 bi0;
bi0 = from[0];
to_next[0] = bi0;
from += 1;
to_next += 1;
n_left_from -= 1;
n_left_to_next -= 1;
b0 = vlib_get_buffer (vm, bi0);
ip0 = vlib_buffer_get_current (b0);
/*
* when this feature is applied on an interface that is already
* accepting packets (because e.g. the interface has other addresses
* assigned) we are looking for the preverbial needle in the haystack
* so assume the packet is not the one we are looking for.
*/
vnet_feature_next (&next0, b0);
/*
* all we are looking for here is DHCP/BOOTP packet-to-client
* UDO port.
*/
if (ip0->protocol == IP_PROTOCOL_UDP)
{
udp0 = (udp_header_t *) (ip0 + 1);
if (dhcp_client_port_network_order == udp0->dst_port)
{
next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
extractions++;
}
}
if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
{
dhcp_client_detect_trace_t *t =
vlib_add_trace (vm, node, b0, sizeof (*t));
t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
}
/* verify speculative enqueue, maybe switch current next frame */
vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
to_next, n_left_to_next,
bi0, next0);
}
vlib_put_next_frame (vm, node, next_index, n_left_to_next);
}
vlib_node_increment_counter (vm, node->node_index,
DHCP_CLIENT_DETECT_ERROR_EXTRACT, extractions);
return frame->n_vectors;
}
/* packet trace format function */
static u8 *
format_dhcp_client_detect_trace (u8 * s, va_list * args)
{
CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
dhcp_client_detect_trace_t *t =
va_arg (*args, dhcp_client_detect_trace_t *);
s = format (s, "dhcp-client-detect: %s", (t->extracted ? "yes" : "no"));
return s;
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (dhcp_client_detect_node) = {
.function = dhcp_client_detect_node_fn,
.name = "ip4-dhcp-client-detect",
.vector_size = sizeof (u32),
.format_trace = format_dhcp_client_detect_trace,
.type = VLIB_NODE_TYPE_INTERNAL,
.n_errors = ARRAY_LEN(dhcp_client_detect_error_strings),
.error_strings = dhcp_client_detect_error_strings,
.n_next_nodes = DHCP_CLIENT_DETECT_N_NEXT,
.next_nodes = {
/*
* Jump straight to the UDP dispatch node thus avoiding
* the RPF checks in ip4-local that will fail
*/
[DHCP_CLIENT_DETECT_NEXT_EXTRACT] = "ip4-udp-lookup",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (dhcp_client_detect_node,
dhcp_client_detect_node_fn);
VNET_FEATURE_INIT (ip4_dvr_reinject_feat_node, static) =
{
.arc_name = "ip4-unicast",
.node_name = "ip4-dhcp-client-detect",
.runs_before = VNET_FEATURES ("ip4-not-enabled"),
};
/* *INDENT-ON* */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
