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Vector Packet Processing
cdp_node.c
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1 /*
2  * Copyright (c) 2011-2016 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 #include <vnet/cdp/cdp_node.h>
16 #include <vnet/ethernet/packet.h>
17 
19 
20 /** \file
21 
22  2 x CDP graph nodes: an "interior" node to process
23  incoming announcements, and a "process" node to periodically
24  send announcements.
25 
26  The interior node is neither pipelined nor dual-looped, because
27  it would be very unusual to see more than one CDP packet in
28  a given input frame. So, it's a very simple / straighforward
29  example.
30 */
31 
32 /*
33  * packet counter strings
34  * Dump these counters via the "show error" CLI command
35  */
36 static char *cdp_error_strings[] = {
37 #define _(sym,string) string,
39 #undef _
40 };
41 
42 /*
43  * We actually send all cdp pkts to the "error" node after scanning
44  * them, so the graph node has only one next-index. The "error-drop"
45  * node automatically bumps our per-node packet counters for us.
46  */
47 typedef enum
48 {
51 } cdp_next_t;
52 
53 /*
54  * Process a frame of cdp packets
55  * Expect 1 packet / frame
56  */
57 static uword
59  vlib_node_runtime_t * node, vlib_frame_t * frame)
60 {
61  u32 n_left_from, *from;
63 
64  from = vlib_frame_vector_args (frame); /* array of buffer indices */
65  n_left_from = frame->n_vectors; /* number of buffer indices */
66 
67  while (n_left_from > 0)
68  {
69  u32 bi0;
70  vlib_buffer_t *b0;
71  u32 next0, error0;
72 
73  bi0 = from[0];
74  b0 = vlib_get_buffer (vm, bi0);
75 
76  next0 = CDP_INPUT_NEXT_NORMAL;
77 
78  /* scan this cdp pkt. error0 is the counter index to bump */
79  error0 = cdp_input (vm, b0, bi0);
80  b0->error = node->errors[error0];
81 
82  /* If this pkt is traced, snapshoot the data */
83  if (b0->flags & VLIB_BUFFER_IS_TRACED)
84  {
85  int len;
86  t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
87  len = (b0->current_length < sizeof (t0->data))
88  ? b0->current_length : sizeof (t0->data);
89  t0->len = len;
90  clib_memcpy (t0->data, vlib_buffer_get_current (b0), len);
91  }
92  /* push this pkt to the next graph node, always error-drop */
93  vlib_set_next_frame_buffer (vm, node, next0, bi0);
94 
95  from += 1;
96  n_left_from -= 1;
97  }
98 
99  return frame->n_vectors;
100 }
101 
102 /*
103  * cdp input graph node declaration
104  */
105 /* *INDENT-OFF* */
107  .function = cdp_node_fn,
108  .name = "cdp-input",
109  .vector_size = sizeof (u32),
110  .type = VLIB_NODE_TYPE_INTERNAL,
111 
112  .n_errors = CDP_N_ERROR,
113  .error_strings = cdp_error_strings,
114 
115  .format_trace = cdp_input_format_trace,
116 
117  .n_next_nodes = CDP_INPUT_N_NEXT,
118  .next_nodes = {
119  [CDP_INPUT_NEXT_NORMAL] = "error-drop",
120  },
121 };
122 /* *INDENT-ON* */
123 
124 /*
125  * cdp periodic function
126  */
127 static uword
129 {
130  cdp_main_t *cm = &cdp_main;
131  f64 poll_time_remaining;
132  uword event_type, *event_data = 0;
133 
134  /* So we can send events to the cdp process */
136 
137  /* Dynamically register the cdp input node with the snap classifier */
138  snap_register_input_protocol (vm, "cdp-input", 0xC /* ieee_oui, Cisco */ ,
139  0x2000 /* protocol CDP */ ,
140  cdp_input_node.index);
141 
142  snap_register_input_protocol (vm, "cdp-input", 0xC /* ieee_oui, Cisco */ ,
143  0x2004 /* protocol CDP */ ,
144  cdp_input_node.index);
145 
146 #if 0 /* retain for reference */
147  /* with the hdlc classifier */
148  hdlc_register_input_protocol (vm, HDLC_PROTOCOL_cdp, cdp_input_node.index);
149 #endif
150 
151  /* with ethernet input (for SRP) */
152  ethernet_register_input_type (vm, ETHERNET_TYPE_CDP /* CDP */ ,
153  cdp_input_node.index);
154 
155  poll_time_remaining = 10.0 /* seconds */ ;
156  while (1)
157  {
158  /* sleep until next poll time, or msg serialize event occurs */
159  poll_time_remaining =
160  vlib_process_wait_for_event_or_clock (vm, poll_time_remaining);
161 
162  event_type = vlib_process_get_events (vm, &event_data);
163  switch (event_type)
164  {
165  case ~0: /* no events => timeout */
166  break;
167 
168  default:
169  clib_warning ("BUG: event type 0x%wx", event_type);
170  break;
171  }
172  if (event_data)
173  _vec_len (event_data) = 0;
174 
175  /* peer timeout scan, send announcements */
176  if (vlib_process_suspend_time_is_zero (poll_time_remaining))
177  {
178  cdp_periodic (vm);
179  poll_time_remaining = 10.0;
180  }
181  }
182 
183  return 0;
184 }
185 
186 /*
187  * cdp periodic node declaration
188  */
189 /* *INDENT-OFF* */
191  .function = cdp_process,
192  .type = VLIB_NODE_TYPE_PROCESS,
193  .name = "cdp-process",
194 };
195 /* *INDENT-ON* */
196 
197 void
199 {
200 }
201 
202 /*
203  * fd.io coding-style-patch-verification: ON
204  *
205  * Local Variables:
206  * eval: (c-set-style "gnu")
207  * End:
208  */
static f64 vlib_process_wait_for_event_or_clock(vlib_main_t *vm, f64 dt)
Suspend a cooperative multi-tasking thread Waits for an event, or for the indicated number of seconds...
Definition: node_funcs.h:699
static void vlib_set_next_frame_buffer(vlib_main_t *vm, vlib_node_runtime_t *node, u32 next_index, u32 buffer_index)
Definition: node_funcs.h:397
static uword cdp_node_fn(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
Definition: cdp_node.c:58
struct _vlib_node_registration vlib_node_registration_t
u32 cdp_process_node_index
Definition: cdp_node.h:88
static vlib_node_registration_t cdp_process_node
(constructor) VLIB_REGISTER_NODE (cdp_process_node)
Definition: cdp_node.c:18
vlib_error_t * errors
Vector of errors for this node.
Definition: node.h:415
cdp_main_t cdp_main
Definition: cdp_input.c:17
static uword vlib_process_suspend_time_is_zero(f64 dt)
Returns TRUE if a process suspend time is less than 10us.
Definition: node_funcs.h:436
cdp_next_t
Definition: cdp_node.c:47
static uword vlib_process_get_events(vlib_main_t *vm, uword **data_vector)
Return the first event type which has occurred and a vector of per-event data of that type...
Definition: node_funcs.h:542
static vlib_node_registration_t cdp_input_node
(constructor) VLIB_REGISTER_NODE (cdp_input_node)
Definition: cdp_node.c:106
#define foreach_cdp_error
Definition: cdp_node.h:101
cdp_error_t cdp_input(vlib_main_t *vm, vlib_buffer_t *b0, u32 bi0)
Definition: cdp_input.c:301
u16 current_length
Nbytes between current data and the end of this buffer.
Definition: buffer.h:72
static void * vlib_buffer_get_current(vlib_buffer_t *b)
Get pointer to current data to process.
Definition: buffer.h:195
static char * cdp_error_strings[]
Definition: cdp_node.c:36
vlib_error_t error
Error code for buffers to be enqueued to error handler.
Definition: buffer.h:113
void vnet_cdp_node_reference(void)
Definition: cdp_node.c:198
void cdp_periodic(vlib_main_t *vm)
Definition: cdp_periodic.c:344
u16 n_vectors
Definition: node.h:344
vlib_main_t * vm
Definition: buffer.c:283
#define clib_warning(format, args...)
Definition: error.h:59
#define VLIB_BUFFER_IS_TRACED
Definition: buffer.h:93
#define clib_memcpy(a, b, c)
Definition: string.h:75
void hdlc_register_input_protocol(vlib_main_t *vm, hdlc_protocol_t protocol, u32 node_index)
Definition: node.c:351
unsigned int u32
Definition: types.h:88
void ethernet_register_input_type(vlib_main_t *vm, ethernet_type_t type, u32 node_index)
Definition: node.c:1355
u64 uword
Definition: types.h:112
static void * vlib_add_trace(vlib_main_t *vm, vlib_node_runtime_t *r, vlib_buffer_t *b, u32 n_data_bytes)
Definition: trace_funcs.h:55
double f64
Definition: types.h:142
static void * vlib_frame_vector_args(vlib_frame_t *f)
Get pointer to frame vector data.
Definition: node_funcs.h:267
#define VLIB_REGISTER_NODE(x,...)
Definition: node.h:143
u8 * cdp_input_format_trace(u8 *s, va_list *args)
Definition: cdp_input.c:462
u32 flags
buffer flags: VLIB_BUFFER_FREE_LIST_INDEX_MASK: bits used to store free list index, VLIB_BUFFER_IS_TRACED: trace this buffer.
Definition: buffer.h:75
static uword cdp_process(vlib_main_t *vm, vlib_node_runtime_t *rt, vlib_frame_t *f)
Definition: cdp_node.c:128
static vlib_buffer_t * vlib_get_buffer(vlib_main_t *vm, u32 buffer_index)
Translate buffer index into buffer pointer.
Definition: buffer_funcs.h:57
void snap_register_input_protocol(vlib_main_t *vm, char *name, u32 ieee_oui, u16 protocol, u32 node_index)
Definition: node.c:311