Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * net/tipc/bearer.h: Include file for TIPC bearer code
  3  *
  4  * Copyright (c) 1996-2006, Ericsson AB
  5  * Copyright (c) 2005, 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_BEARER_H
 38 #define _TIPC_BEARER_H
 39 
 40 #include "core.h"
 41 #include "bcast.h"
 42 
 43 #define MAX_BEARERS 8
 44 #define MAX_MEDIA 4
 45 
 46 
 47 /**
 48  * struct media - TIPC media information available to internal users
 49  * @send_msg: routine which handles buffer transmission
 50  * @enable_bearer: routine which enables a bearer
 51  * @disable_bearer: routine which disables a bearer
 52  * @addr2str: routine which converts bearer's address to string form
 53  * @bcast_addr: media address used in broadcasting
 54  * @bcast: non-zero if media supports broadcasting [currently mandatory]
 55  * @priority: default link (and bearer) priority
 56  * @tolerance: default time (in ms) before declaring link failure
 57  * @window: default window (in packets) before declaring link congestion
 58  * @type_id: TIPC media identifier [defined in tipc_bearer.h]
 59  * @name: media name
 60  */
 61 
 62 struct media {
 63         int (*send_msg)(struct sk_buff *buf,
 64                         struct tipc_bearer *b_ptr,
 65                         struct tipc_media_addr *dest);
 66         int (*enable_bearer)(struct tipc_bearer *b_ptr);
 67         void (*disable_bearer)(struct tipc_bearer *b_ptr);
 68         char *(*addr2str)(struct tipc_media_addr *a,
 69                           char *str_buf, int str_size);
 70         struct tipc_media_addr bcast_addr;
 71         int bcast;
 72         u32 priority;
 73         u32 tolerance;
 74         u32 window;
 75         u32 type_id;
 76         char name[TIPC_MAX_MEDIA_NAME];
 77 };
 78 
 79 /**
 80  * struct bearer - TIPC bearer information available to internal users
 81  * @publ: bearer information available to privileged users
 82  * @media: ptr to media structure associated with bearer
 83  * @priority: default link priority for bearer
 84  * @detect_scope: network address mask used during automatic link creation
 85  * @identity: array index of this bearer within TIPC bearer array
 86  * @link_req: ptr to (optional) structure making periodic link setup requests
 87  * @links: list of non-congested links associated with bearer
 88  * @cong_links: list of congested links associated with bearer
 89  * @continue_count: # of times bearer has resumed after congestion or blocking
 90  * @active: non-zero if bearer structure is represents a bearer
 91  * @net_plane: network plane ('A' through 'H') currently associated with bearer
 92  * @nodes: indicates which nodes in cluster can be reached through bearer
 93  */
 94 
 95 struct bearer {
 96         struct tipc_bearer publ;
 97         struct media *media;
 98         u32 priority;
 99         u32 detect_scope;
100         u32 identity;
101         struct link_req *link_req;
102         struct list_head links;
103         struct list_head cong_links;
104         u32 continue_count;
105         int active;
106         char net_plane;
107         struct tipc_node_map nodes;
108 };
109 
110 struct bearer_name {
111         char media_name[TIPC_MAX_MEDIA_NAME];
112         char if_name[TIPC_MAX_IF_NAME];
113 };
114 
115 struct link;
116 
117 extern struct bearer *tipc_bearers;
118 
119 void tipc_media_addr_printf(struct print_buf *pb, struct tipc_media_addr *a);
120 struct sk_buff *tipc_media_get_names(void);
121 
122 struct sk_buff *tipc_bearer_get_names(void);
123 void tipc_bearer_add_dest(struct bearer *b_ptr, u32 dest);
124 void tipc_bearer_remove_dest(struct bearer *b_ptr, u32 dest);
125 void tipc_bearer_schedule(struct bearer *b_ptr, struct link *l_ptr);
126 struct bearer *tipc_bearer_find_interface(const char *if_name);
127 int tipc_bearer_resolve_congestion(struct bearer *b_ptr, struct link *l_ptr);
128 int tipc_bearer_init(void);
129 void tipc_bearer_stop(void);
130 void tipc_bearer_lock_push(struct bearer *b_ptr);
131 
132 
133 /**
134  * tipc_bearer_send- sends buffer to destination over bearer
135  *
136  * Returns true (1) if successful, or false (0) if unable to send
137  *
138  * IMPORTANT:
139  * The media send routine must not alter the buffer being passed in
140  * as it may be needed for later retransmission!
141  *
142  * If the media send routine returns a non-zero value (indicating that
143  * it was unable to send the buffer), it must:
144  *   1) mark the bearer as blocked,
145  *   2) call tipc_continue() once the bearer is able to send again.
146  * Media types that are unable to meet these two critera must ensure their
147  * send routine always returns success -- even if the buffer was not sent --
148  * and let TIPC's link code deal with the undelivered message.
149  */
150 
151 static inline int tipc_bearer_send(struct bearer *b_ptr, struct sk_buff *buf,
152                                    struct tipc_media_addr *dest)
153 {
154         return !b_ptr->media->send_msg(buf, &b_ptr->publ, dest);
155 }
156 
157 /**
158  * tipc_bearer_congested - determines if bearer is currently congested
159  */
160 
161 static inline int tipc_bearer_congested(struct bearer *b_ptr, struct link *l_ptr)
162 {
163         if (unlikely(b_ptr->publ.blocked))
164                 return 1;
165         if (likely(list_empty(&b_ptr->cong_links)))
166                 return 0;
167         return !tipc_bearer_resolve_congestion(b_ptr, l_ptr);
168 }
169 
170 #endif
171 
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