source: mainline/uspace/srv/net/tl/tcp/tqueue.c@ 7a8c1c4e

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 7a8c1c4e was bbf159a, checked in by Jiri Svoboda <jiri@…>, 14 years ago

Eliminate busy waiting when TCP send buffer is full.
  • Property mode set to 100644
File size: 9.1 KB
Line 
1/*
2 * Copyright (c) 2011 Jiri Svoboda
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup tcp
30 * @{
31 */
32
33/**
34 * @file TCP transmission queue
35 */
36
37#include <adt/list.h>
38#include <errno.h>
39#include <fibril_synch.h>
40#include <byteorder.h>
41#include <io/log.h>
42#include <macros.h>
43#include <mem.h>
44#include <stdlib.h>
45#include "conn.h"
46#include "ncsim.h"
47#include "pdu.h"
48#include "rqueue.h"
49#include "segment.h"
50#include "seq_no.h"
51#include "tqueue.h"
52#include "tcp.h"
53#include "tcp_type.h"
54
55#define RETRANSMIT_TIMEOUT (2*1000*1000)
56
57static void retransmit_timeout_func(void *arg);
58static void tcp_tqueue_timer_set(tcp_conn_t *conn);
59static void tcp_tqueue_timer_clear(tcp_conn_t *conn);
60
61int tcp_tqueue_init(tcp_tqueue_t *tqueue, tcp_conn_t *conn)
62{
63 tqueue->conn = conn;
64 tqueue->timer = fibril_timer_create();
65 if (tqueue->timer == NULL)
66 return ENOMEM;
67
68 list_initialize(&tqueue->list);
69
70 return EOK;
71}
72
73void tcp_tqueue_clear(tcp_tqueue_t *tqueue)
74{
75 tcp_tqueue_timer_clear(tqueue->conn);
76}
77
78void tcp_tqueue_fini(tcp_tqueue_t *tqueue)
79{
80 if (tqueue->timer != NULL) {
81 fibril_timer_destroy(tqueue->timer);
82 tqueue->timer = NULL;
83 }
84}
85
86void tcp_tqueue_ctrl_seg(tcp_conn_t *conn, tcp_control_t ctrl)
87{
88 tcp_segment_t *seg;
89
90 log_msg(LVL_DEBUG, "tcp_tqueue_ctrl_seg(%p, %u)", conn, ctrl);
91
92 seg = tcp_segment_make_ctrl(ctrl);
93 tcp_tqueue_seg(conn, seg);
94}
95
96void tcp_tqueue_seg(tcp_conn_t *conn, tcp_segment_t *seg)
97{
98 tcp_segment_t *rt_seg;
99 tcp_tqueue_entry_t *tqe;
100
101 log_msg(LVL_DEBUG, "%s: tcp_tqueue_seg(%p, %p)", conn->name, conn,
102 seg);
103
104 /*
105 * Add segment to retransmission queue
106 */
107
108 if (seg->len > 0) {
109 rt_seg = tcp_segment_dup(seg);
110 if (rt_seg == NULL) {
111 log_msg(LVL_ERROR, "Memory allocation failed.");
112 /* XXX Handle properly */
113 return;
114 }
115
116 tqe = calloc(1, sizeof(tcp_tqueue_entry_t));
117 if (tqe == NULL) {
118 log_msg(LVL_ERROR, "Memory allocation failed.");
119 /* XXX Handle properly */
120 return;
121 }
122
123 tqe->conn = conn;
124 tqe->seg = rt_seg;
125 rt_seg->seq = conn->snd_nxt;
126
127 list_append(&tqe->link, &conn->retransmit.list);
128
129 /* Set retransmission timer */
130 tcp_tqueue_timer_set(conn);
131 }
132
133 tcp_prepare_transmit_segment(conn, seg);
134}
135
136void tcp_prepare_transmit_segment(tcp_conn_t *conn, tcp_segment_t *seg)
137{
138 /*
139 * Always send ACK once we have received SYN, except for RST segments.
140 * (Spec says we should always send ACK once connection has been
141 * established.)
142 */
143 if (tcp_conn_got_syn(conn) && (seg->ctrl & CTL_RST) == 0)
144 seg->ctrl |= CTL_ACK;
145
146 seg->seq = conn->snd_nxt;
147 conn->snd_nxt += seg->len;
148
149 tcp_conn_transmit_segment(conn, seg);
150}
151
152/** Transmit data from the send buffer.
153 *
154 * @param conn Connection
155 */
156void tcp_tqueue_new_data(tcp_conn_t *conn)
157{
158 size_t avail_wnd;
159 size_t xfer_seqlen;
160 size_t snd_buf_seqlen;
161 size_t data_size;
162 tcp_control_t ctrl;
163 bool send_fin;
164
165 tcp_segment_t *seg;
166
167 log_msg(LVL_DEBUG, "%s: tcp_tqueue_new_data()", conn->name);
168
169 fibril_mutex_lock(&conn->snd_buf_lock);
170
171 /* Number of free sequence numbers in send window */
172 avail_wnd = (conn->snd_una + conn->snd_wnd) - conn->snd_nxt;
173 snd_buf_seqlen = conn->snd_buf_used + (conn->snd_buf_fin ? 1 : 0);
174
175 xfer_seqlen = min(snd_buf_seqlen, avail_wnd);
176 log_msg(LVL_DEBUG, "%s: snd_buf_seqlen = %zu, SND.WND = %zu, "
177 "xfer_seqlen = %zu", conn->name, snd_buf_seqlen, conn->snd_wnd,
178 xfer_seqlen);
179
180 if (xfer_seqlen == 0) {
181 fibril_mutex_unlock(&conn->snd_buf_lock);
182 return;
183 }
184
185 /* XXX Do not always send immediately */
186
187 send_fin = conn->snd_buf_fin && xfer_seqlen == snd_buf_seqlen;
188 data_size = xfer_seqlen - (send_fin ? 1 : 0);
189
190 if (send_fin) {
191 log_msg(LVL_DEBUG, "%s: Sending out FIN.", conn->name);
192 /* We are sending out FIN */
193 ctrl = CTL_FIN;
194 } else {
195 ctrl = 0;
196 }
197
198 seg = tcp_segment_make_data(ctrl, conn->snd_buf, data_size);
199 if (seg == NULL) {
200 fibril_mutex_unlock(&conn->snd_buf_lock);
201 log_msg(LVL_ERROR, "Memory allocation failure.");
202 return;
203 }
204
205 /* Remove data from send buffer */
206 memmove(conn->snd_buf, conn->snd_buf + data_size,
207 conn->snd_buf_used - data_size);
208 conn->snd_buf_used -= data_size;
209
210 if (send_fin)
211 conn->snd_buf_fin = false;
212
213 fibril_condvar_broadcast(&conn->snd_buf_cv);
214 fibril_mutex_unlock(&conn->snd_buf_lock);
215
216 if (send_fin)
217 tcp_conn_fin_sent(conn);
218
219 tcp_tqueue_seg(conn, seg);
220}
221
222/** Remove ACKed segments from retransmission queue and possibly transmit
223 * more data.
224 *
225 * This should be called when SND.UNA is updated due to incoming ACK.
226 */
227void tcp_tqueue_ack_received(tcp_conn_t *conn)
228{
229 link_t *cur, *next;
230
231 log_msg(LVL_DEBUG, "%s: tcp_tqueue_ack_received(%p)", conn->name,
232 conn);
233
234 cur = conn->retransmit.list.head.next;
235
236 while (cur != &conn->retransmit.list.head) {
237 next = cur->next;
238
239 tcp_tqueue_entry_t *tqe = list_get_instance(cur,
240 tcp_tqueue_entry_t, link);
241
242 if (seq_no_segment_acked(conn, tqe->seg, conn->snd_una)) {
243 /* Remove acknowledged segment */
244 list_remove(cur);
245
246 if ((tqe->seg->ctrl & CTL_FIN) != 0) {
247 log_msg(LVL_DEBUG, "Fin has been acked");
248 log_msg(LVL_DEBUG, "SND.UNA=%" PRIu32
249 " SEG.SEQ=%" PRIu32 " SEG.LEN=%" PRIu32,
250 conn->snd_una, tqe->seg->seq, tqe->seg->len);
251 /* Our FIN has been acked */
252 conn->fin_is_acked = true;
253 }
254
255 tcp_segment_delete(tqe->seg);
256 free(tqe);
257
258 /* Reset retransmission timer */
259 tcp_tqueue_timer_set(conn);
260 }
261
262 cur = next;
263 }
264
265 /* Clear retransmission timer if the queue is empty. */
266 if (list_empty(&conn->retransmit.list))
267 tcp_tqueue_timer_clear(conn);
268
269 /* Possibly transmit more data */
270 tcp_tqueue_new_data(conn);
271}
272
273void tcp_conn_transmit_segment(tcp_conn_t *conn, tcp_segment_t *seg)
274{
275 log_msg(LVL_DEBUG, "%s: tcp_conn_transmit_segment(%p, %p)",
276 conn->name, conn, seg);
277
278 seg->wnd = conn->rcv_wnd;
279
280 if ((seg->ctrl & CTL_ACK) != 0)
281 seg->ack = conn->rcv_nxt;
282 else
283 seg->ack = 0;
284
285 tcp_transmit_segment(&conn->ident, seg);
286}
287
288void tcp_transmit_segment(tcp_sockpair_t *sp, tcp_segment_t *seg)
289{
290 log_msg(LVL_DEBUG, "tcp_transmit_segment(f:(%x,%u),l:(%x,%u), %p)",
291 sp->foreign.addr.ipv4, sp->foreign.port,
292 sp->local.addr.ipv4, sp->local.port, seg);
293
294 log_msg(LVL_DEBUG, "SEG.SEQ=%" PRIu32 ", SEG.WND=%" PRIu32,
295 seg->seq, seg->wnd);
296
297 tcp_segment_dump(seg);
298/*
299 tcp_pdu_prepare(conn, seg, &data, &len);
300 tcp_pdu_transmit(data, len);
301*/
302// tcp_rqueue_bounce_seg(sp, seg);
303// tcp_ncsim_bounce_seg(sp, seg);
304
305 tcp_pdu_t *pdu;
306
307 if (tcp_pdu_encode(sp, seg, &pdu) != EOK) {
308 log_msg(LVL_WARN, "Not enough memory. Segment dropped.");
309 return;
310 }
311
312 tcp_transmit_pdu(pdu);
313 tcp_pdu_delete(pdu);
314}
315
316static void retransmit_timeout_func(void *arg)
317{
318 tcp_conn_t *conn = (tcp_conn_t *) arg;
319 tcp_tqueue_entry_t *tqe;
320 tcp_segment_t *rt_seg;
321 link_t *link;
322
323 log_msg(LVL_DEBUG, "### %s: retransmit_timeout_func(%p)", conn->name, conn);
324
325 if (conn->cstate == st_closed) {
326 log_msg(LVL_DEBUG, "Connection already closed.");
327 return;
328 }
329
330 link = list_first(&conn->retransmit.list);
331 if (link == NULL) {
332 log_msg(LVL_DEBUG, "Nothing to retransmit");
333 return;
334 }
335
336 tqe = list_get_instance(link, tcp_tqueue_entry_t, link);
337
338 rt_seg = tcp_segment_dup(tqe->seg);
339 if (rt_seg == NULL) {
340 log_msg(LVL_ERROR, "Memory allocation failed.");
341 /* XXX Handle properly */
342 return;
343 }
344
345 log_msg(LVL_DEBUG, "### %s: retransmitting segment", conn->name);
346 tcp_conn_transmit_segment(tqe->conn, rt_seg);
347
348 /* Reset retransmission timer */
349 tcp_tqueue_timer_set(tqe->conn);
350}
351
352/** Set or re-set retransmission timer */
353static void tcp_tqueue_timer_set(tcp_conn_t *conn)
354{
355 log_msg(LVL_DEBUG, "### %s: tcp_tqueue_timer_set()", conn->name);
356
357 (void) retransmit_timeout_func;
358 fibril_timer_set(conn->retransmit.timer, RETRANSMIT_TIMEOUT,
359 retransmit_timeout_func, (void *) conn);
360}
361
362/** Clear retransmission timer */
363static void tcp_tqueue_timer_clear(tcp_conn_t *conn)
364{
365 log_msg(LVL_DEBUG, "### %s: tcp_tqueue_timer_clear()", conn->name);
366
367 fibril_timer_clear(conn->retransmit.timer);
368}
369
370/**
371 * @}
372 */
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