xref: /linux/net/dccp/ccids/lib/packet_history.c (revision f24e9f586b377749dff37554696cf3a105540c94)
1 /*
2  *  net/dccp/packet_history.c
3  *
4  *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
5  *
6  *  An implementation of the DCCP protocol
7  *
8  *  This code has been developed by the University of Waikato WAND
9  *  research group. For further information please see http://www.wand.net.nz/
10  *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
11  *
12  *  This code also uses code from Lulea University, rereleased as GPL by its
13  *  authors:
14  *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
15  *
16  *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17  *  and to make it work as a loadable module in the DCCP stack written by
18  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
19  *
20  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
21  *
22  *  This program is free software; you can redistribute it and/or modify
23  *  it under the terms of the GNU General Public License as published by
24  *  the Free Software Foundation; either version 2 of the License, or
25  *  (at your option) any later version.
26  *
27  *  This program is distributed in the hope that it will be useful,
28  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
29  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
30  *  GNU General Public License for more details.
31  *
32  *  You should have received a copy of the GNU General Public License
33  *  along with this program; if not, write to the Free Software
34  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
35  */
36 
37 #include <linux/module.h>
38 #include <linux/string.h>
39 
40 #include "packet_history.h"
41 
42 struct dccp_rx_hist *dccp_rx_hist_new(const char *name)
43 {
44 	struct dccp_rx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
45 	static const char dccp_rx_hist_mask[] = "rx_hist_%s";
46 	char *slab_name;
47 
48 	if (hist == NULL)
49 		goto out;
50 
51 	slab_name = kmalloc(strlen(name) + sizeof(dccp_rx_hist_mask) - 1,
52 			    GFP_ATOMIC);
53 	if (slab_name == NULL)
54 		goto out_free_hist;
55 
56 	sprintf(slab_name, dccp_rx_hist_mask, name);
57 	hist->dccprxh_slab = kmem_cache_create(slab_name,
58 					     sizeof(struct dccp_rx_hist_entry),
59 					       0, SLAB_HWCACHE_ALIGN,
60 					       NULL, NULL);
61 	if (hist->dccprxh_slab == NULL)
62 		goto out_free_slab_name;
63 out:
64 	return hist;
65 out_free_slab_name:
66 	kfree(slab_name);
67 out_free_hist:
68 	kfree(hist);
69 	hist = NULL;
70 	goto out;
71 }
72 
73 EXPORT_SYMBOL_GPL(dccp_rx_hist_new);
74 
75 void dccp_rx_hist_delete(struct dccp_rx_hist *hist)
76 {
77 	const char* name = kmem_cache_name(hist->dccprxh_slab);
78 
79 	kmem_cache_destroy(hist->dccprxh_slab);
80 	kfree(name);
81 	kfree(hist);
82 }
83 
84 EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);
85 
86 void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
87 {
88 	struct dccp_rx_hist_entry *entry, *next;
89 
90 	list_for_each_entry_safe(entry, next, list, dccphrx_node) {
91 		list_del_init(&entry->dccphrx_node);
92 		kmem_cache_free(hist->dccprxh_slab, entry);
93 	}
94 }
95 
96 EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
97 
98 struct dccp_rx_hist_entry *
99 		dccp_rx_hist_find_data_packet(const struct list_head *list)
100 {
101 	struct dccp_rx_hist_entry *entry, *packet = NULL;
102 
103 	list_for_each_entry(entry, list, dccphrx_node)
104 		if (entry->dccphrx_type == DCCP_PKT_DATA ||
105 		    entry->dccphrx_type == DCCP_PKT_DATAACK) {
106 			packet = entry;
107 			break;
108 		}
109 
110 	return packet;
111 }
112 
113 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
114 
115 void dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
116 			    struct list_head *rx_list,
117 			    struct list_head *li_list,
118 			    struct dccp_rx_hist_entry *packet,
119 			    u64 nonloss_seqno)
120 {
121 	struct dccp_rx_hist_entry *entry, *next;
122 	u8 num_later = 0;
123 
124 	list_add(&packet->dccphrx_node, rx_list);
125 
126 	num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
127 
128 	if (!list_empty(li_list)) {
129 		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
130 			if (num_later == 0) {
131 				if (after48(nonloss_seqno,
132 				   entry->dccphrx_seqno)) {
133 					list_del_init(&entry->dccphrx_node);
134 					dccp_rx_hist_entry_delete(hist, entry);
135 				}
136 			} else if (dccp_rx_hist_entry_data_packet(entry))
137 				--num_later;
138 		}
139 	} else {
140 		int step = 0;
141 		u8 win_count = 0; /* Not needed, but lets shut up gcc */
142 		int tmp;
143 		/*
144 		 * We have no loss interval history so we need at least one
145 		 * rtt:s of data packets to approximate rtt.
146 		 */
147 		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
148 			if (num_later == 0) {
149 				switch (step) {
150 				case 0:
151 					step = 1;
152 					/* OK, find next data packet */
153 					num_later = 1;
154 					break;
155 				case 1:
156 					step = 2;
157 					/* OK, find next data packet */
158 					num_later = 1;
159 					win_count = entry->dccphrx_ccval;
160 					break;
161 				case 2:
162 					tmp = win_count - entry->dccphrx_ccval;
163 					if (tmp < 0)
164 						tmp += TFRC_WIN_COUNT_LIMIT;
165 					if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
166 						/*
167 						 * We have found a packet older
168 						 * than one rtt remove the rest
169 						 */
170 						step = 3;
171 					} else /* OK, find next data packet */
172 						num_later = 1;
173 					break;
174 				case 3:
175 					list_del_init(&entry->dccphrx_node);
176 					dccp_rx_hist_entry_delete(hist, entry);
177 					break;
178 				}
179 			} else if (dccp_rx_hist_entry_data_packet(entry))
180 				--num_later;
181 		}
182 	}
183 }
184 
185 EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
186 
187 struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
188 {
189 	struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
190 	static const char dccp_tx_hist_mask[] = "tx_hist_%s";
191 	char *slab_name;
192 
193 	if (hist == NULL)
194 		goto out;
195 
196 	slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
197 			    GFP_ATOMIC);
198 	if (slab_name == NULL)
199 		goto out_free_hist;
200 
201 	sprintf(slab_name, dccp_tx_hist_mask, name);
202 	hist->dccptxh_slab = kmem_cache_create(slab_name,
203 					     sizeof(struct dccp_tx_hist_entry),
204 					       0, SLAB_HWCACHE_ALIGN,
205 					       NULL, NULL);
206 	if (hist->dccptxh_slab == NULL)
207 		goto out_free_slab_name;
208 out:
209 	return hist;
210 out_free_slab_name:
211 	kfree(slab_name);
212 out_free_hist:
213 	kfree(hist);
214 	hist = NULL;
215 	goto out;
216 }
217 
218 EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
219 
220 void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
221 {
222 	const char* name = kmem_cache_name(hist->dccptxh_slab);
223 
224 	kmem_cache_destroy(hist->dccptxh_slab);
225 	kfree(name);
226 	kfree(hist);
227 }
228 
229 EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
230 
231 struct dccp_tx_hist_entry *
232 	dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
233 {
234 	struct dccp_tx_hist_entry *packet = NULL, *entry;
235 
236 	list_for_each_entry(entry, list, dccphtx_node)
237 		if (entry->dccphtx_seqno == seq) {
238 			packet = entry;
239 			break;
240 		}
241 
242 	return packet;
243 }
244 
245 EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
246 
247 int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
248    u8 *ccval)
249 {
250 	struct dccp_rx_hist_entry *packet = NULL, *entry;
251 
252 	list_for_each_entry(entry, list, dccphrx_node)
253 		if (entry->dccphrx_seqno == seq) {
254 			packet = entry;
255 			break;
256 		}
257 
258 	if (packet)
259 		*ccval = packet->dccphrx_ccval;
260 
261 	return packet != NULL;
262 }
263 
264 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
265 
266 void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
267 			      struct list_head *list,
268 			      struct dccp_tx_hist_entry *packet)
269 {
270 	struct dccp_tx_hist_entry *next;
271 
272 	list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
273 		list_del_init(&packet->dccphtx_node);
274 		dccp_tx_hist_entry_delete(hist, packet);
275 	}
276 }
277 
278 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
279 
280 void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
281 {
282 	struct dccp_tx_hist_entry *entry, *next;
283 
284 	list_for_each_entry_safe(entry, next, list, dccphtx_node) {
285 		list_del_init(&entry->dccphtx_node);
286 		dccp_tx_hist_entry_delete(hist, entry);
287 	}
288 }
289 
290 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
291 
292 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
293 	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
294 MODULE_DESCRIPTION("DCCP TFRC library");
295 MODULE_LICENSE("GPL");
296