1 /*
2  * net/tipc/link.h: Include file for TIPC link code
3  *
4  * Copyright (c) 1995-2006, Ericsson AB
5  * Copyright (c) 2004-2005, 2010-2011, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #ifndef _TIPC_LINK_H
38 #define _TIPC_LINK_H
39 
40 #include "log.h"
41 #include "msg.h"
42 #include "node.h"
43 
44 #define PUSH_FAILED   1
45 #define PUSH_FINISHED 2
46 
47 /*
48  * Out-of-range value for link sequence numbers
49  */
50 
51 #define INVALID_LINK_SEQ 0x10000
52 
53 /*
54  * Link states
55  */
56 
57 #define WORKING_WORKING 560810u
58 #define WORKING_UNKNOWN 560811u
59 #define RESET_UNKNOWN   560812u
60 #define RESET_RESET     560813u
61 
62 /*
63  * Starting value for maximum packet size negotiation on unicast links
64  * (unless bearer MTU is less)
65  */
66 
67 #define MAX_PKT_DEFAULT 1500
68 
69 /**
70  * struct tipc_link - TIPC link data structure
71  * @addr: network address of link's peer node
72  * @name: link name character string
73  * @media_addr: media address to use when sending messages over link
74  * @timer: link timer
75  * @owner: pointer to peer node
76  * @link_list: adjacent links in bearer's list of links
77  * @started: indicates if link has been started
78  * @checkpoint: reference point for triggering link continuity checking
79  * @peer_session: link session # being used by peer end of link
80  * @peer_bearer_id: bearer id used by link's peer endpoint
81  * @b_ptr: pointer to bearer used by link
82  * @tolerance: minimum link continuity loss needed to reset link [in ms]
83  * @continuity_interval: link continuity testing interval [in ms]
84  * @abort_limit: # of unacknowledged continuity probes needed to reset link
85  * @state: current state of link FSM
86  * @blocked: indicates if link has been administratively blocked
87  * @fsm_msg_cnt: # of protocol messages link FSM has sent in current state
88  * @proto_msg: template for control messages generated by link
89  * @pmsg: convenience pointer to "proto_msg" field
90  * @priority: current link priority
91  * @queue_limit: outbound message queue congestion thresholds (indexed by user)
92  * @exp_msg_count: # of tunnelled messages expected during link changeover
93  * @reset_checkpoint: seq # of last acknowledged message at time of link reset
94  * @max_pkt: current maximum packet size for this link
95  * @max_pkt_target: desired maximum packet size for this link
96  * @max_pkt_probes: # of probes based on current (max_pkt, max_pkt_target)
97  * @out_queue_size: # of messages in outbound message queue
98  * @first_out: ptr to first outbound message in queue
99  * @last_out: ptr to last outbound message in queue
100  * @next_out_no: next sequence number to use for outbound messages
101  * @last_retransmitted: sequence number of most recently retransmitted message
102  * @stale_count: # of identical retransmit requests made by peer
103  * @next_in_no: next sequence number to expect for inbound messages
104  * @deferred_inqueue_sz: # of messages in inbound message queue
105  * @oldest_deferred_in: ptr to first inbound message in queue
106  * @newest_deferred_in: ptr to last inbound message in queue
107  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
108  * @proto_msg_queue: ptr to (single) outbound control message
109  * @retransm_queue_size: number of messages to retransmit
110  * @retransm_queue_head: sequence number of first message to retransmit
111  * @next_out: ptr to first unsent outbound message in queue
112  * @waiting_ports: linked list of ports waiting for link congestion to abate
113  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
114  * @defragm_buf: list of partially reassembled inbound message fragments
115  * @stats: collects statistics regarding link activity
116  */
117 
118 struct tipc_link {
119 	u32 addr;
120 	char name[TIPC_MAX_LINK_NAME];
121 	struct tipc_media_addr media_addr;
122 	struct timer_list timer;
123 	struct tipc_node *owner;
124 	struct list_head link_list;
125 
126 	/* Management and link supervision data */
127 	int started;
128 	u32 checkpoint;
129 	u32 peer_session;
130 	u32 peer_bearer_id;
131 	struct tipc_bearer *b_ptr;
132 	u32 tolerance;
133 	u32 continuity_interval;
134 	u32 abort_limit;
135 	int state;
136 	int blocked;
137 	u32 fsm_msg_cnt;
138 	struct {
139 		unchar hdr[INT_H_SIZE];
140 		unchar body[TIPC_MAX_IF_NAME];
141 	} proto_msg;
142 	struct tipc_msg *pmsg;
143 	u32 priority;
144 	u32 queue_limit[15];	/* queue_limit[0]==window limit */
145 
146 	/* Changeover */
147 	u32 exp_msg_count;
148 	u32 reset_checkpoint;
149 
150 	/* Max packet negotiation */
151 	u32 max_pkt;
152 	u32 max_pkt_target;
153 	u32 max_pkt_probes;
154 
155 	/* Sending */
156 	u32 out_queue_size;
157 	struct sk_buff *first_out;
158 	struct sk_buff *last_out;
159 	u32 next_out_no;
160 	u32 last_retransmitted;
161 	u32 stale_count;
162 
163 	/* Reception */
164 	u32 next_in_no;
165 	u32 deferred_inqueue_sz;
166 	struct sk_buff *oldest_deferred_in;
167 	struct sk_buff *newest_deferred_in;
168 	u32 unacked_window;
169 
170 	/* Congestion handling */
171 	struct sk_buff *proto_msg_queue;
172 	u32 retransm_queue_size;
173 	u32 retransm_queue_head;
174 	struct sk_buff *next_out;
175 	struct list_head waiting_ports;
176 
177 	/* Fragmentation/defragmentation */
178 	u32 long_msg_seq_no;
179 	struct sk_buff *defragm_buf;
180 
181 	/* Statistics */
182 	struct {
183 		u32 sent_info;		/* used in counting # sent packets */
184 		u32 recv_info;		/* used in counting # recv'd packets */
185 		u32 sent_states;
186 		u32 recv_states;
187 		u32 sent_probes;
188 		u32 recv_probes;
189 		u32 sent_nacks;
190 		u32 recv_nacks;
191 		u32 sent_acks;
192 		u32 sent_bundled;
193 		u32 sent_bundles;
194 		u32 recv_bundled;
195 		u32 recv_bundles;
196 		u32 retransmitted;
197 		u32 sent_fragmented;
198 		u32 sent_fragments;
199 		u32 recv_fragmented;
200 		u32 recv_fragments;
201 		u32 link_congs;		/* # port sends blocked by congestion */
202 		u32 bearer_congs;
203 		u32 deferred_recv;
204 		u32 duplicates;
205 		u32 max_queue_sz;	/* send queue size high water mark */
206 		u32 accu_queue_sz;	/* used for send queue size profiling */
207 		u32 queue_sz_counts;	/* used for send queue size profiling */
208 		u32 msg_length_counts;	/* used for message length profiling */
209 		u32 msg_lengths_total;	/* used for message length profiling */
210 		u32 msg_length_profile[7]; /* used for msg. length profiling */
211 	} stats;
212 };
213 
214 struct tipc_port;
215 
216 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
217 			      struct tipc_bearer *b_ptr,
218 			      const struct tipc_media_addr *media_addr);
219 void tipc_link_delete(struct tipc_link *l_ptr);
220 void tipc_link_changeover(struct tipc_link *l_ptr);
221 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *dest);
222 void tipc_link_reset_fragments(struct tipc_link *l_ptr);
223 int tipc_link_is_up(struct tipc_link *l_ptr);
224 int tipc_link_is_active(struct tipc_link *l_ptr);
225 u32 tipc_link_push_packet(struct tipc_link *l_ptr);
226 void tipc_link_stop(struct tipc_link *l_ptr);
227 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space, u16 cmd);
228 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space);
229 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space);
230 void tipc_link_reset(struct tipc_link *l_ptr);
231 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector);
232 void tipc_link_send_names(struct list_head *message_list, u32 dest);
233 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
234 u32 tipc_link_get_max_pkt(u32 dest, u32 selector);
235 int tipc_link_send_sections_fast(struct tipc_port *sender,
236 				 struct iovec const *msg_sect,
237 				 const u32 num_sect,
238 				 unsigned int total_len,
239 				 u32 destnode);
240 void tipc_link_recv_bundle(struct sk_buff *buf);
241 int  tipc_link_recv_fragment(struct sk_buff **pending,
242 			     struct sk_buff **fb,
243 			     struct tipc_msg **msg);
244 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ, int prob,
245 			      u32 gap, u32 tolerance, u32 priority,
246 			      u32 acked_mtu);
247 void tipc_link_push_queue(struct tipc_link *l_ptr);
248 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
249 		   struct sk_buff *buf);
250 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all);
251 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window);
252 void tipc_link_retransmit(struct tipc_link *l_ptr,
253 			  struct sk_buff *start, u32 retransmits);
254 
255 /*
256  * Link sequence number manipulation routines (uses modulo 2**16 arithmetic)
257  */
258 
buf_seqno(struct sk_buff * buf)259 static inline u32 buf_seqno(struct sk_buff *buf)
260 {
261 	return msg_seqno(buf_msg(buf));
262 }
263 
mod(u32 x)264 static inline u32 mod(u32 x)
265 {
266 	return x & 0xffffu;
267 }
268 
between(u32 lower,u32 upper,u32 n)269 static inline int between(u32 lower, u32 upper, u32 n)
270 {
271 	if ((lower < n) && (n < upper))
272 		return 1;
273 	if ((upper < lower) && ((n > lower) || (n < upper)))
274 		return 1;
275 	return 0;
276 }
277 
less_eq(u32 left,u32 right)278 static inline int less_eq(u32 left, u32 right)
279 {
280 	return mod(right - left) < 32768u;
281 }
282 
less(u32 left,u32 right)283 static inline int less(u32 left, u32 right)
284 {
285 	return less_eq(left, right) && (mod(right) != mod(left));
286 }
287 
lesser(u32 left,u32 right)288 static inline u32 lesser(u32 left, u32 right)
289 {
290 	return less_eq(left, right) ? left : right;
291 }
292 
293 
294 /*
295  * Link status checking routines
296  */
297 
link_working_working(struct tipc_link * l_ptr)298 static inline int link_working_working(struct tipc_link *l_ptr)
299 {
300 	return l_ptr->state == WORKING_WORKING;
301 }
302 
link_working_unknown(struct tipc_link * l_ptr)303 static inline int link_working_unknown(struct tipc_link *l_ptr)
304 {
305 	return l_ptr->state == WORKING_UNKNOWN;
306 }
307 
link_reset_unknown(struct tipc_link * l_ptr)308 static inline int link_reset_unknown(struct tipc_link *l_ptr)
309 {
310 	return l_ptr->state == RESET_UNKNOWN;
311 }
312 
link_reset_reset(struct tipc_link * l_ptr)313 static inline int link_reset_reset(struct tipc_link *l_ptr)
314 {
315 	return l_ptr->state == RESET_RESET;
316 }
317 
link_blocked(struct tipc_link * l_ptr)318 static inline int link_blocked(struct tipc_link *l_ptr)
319 {
320 	return l_ptr->exp_msg_count || l_ptr->blocked;
321 }
322 
link_congested(struct tipc_link * l_ptr)323 static inline int link_congested(struct tipc_link *l_ptr)
324 {
325 	return l_ptr->out_queue_size >= l_ptr->queue_limit[0];
326 }
327 
328 #endif
329