2 utcp.c -- Userspace TCP
3 Copyright (C) 2014 Guus Sliepen <guus@tinc-vpn.org>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
31 #include <sys/socket.h>
33 #include "utcp_priv.h"
48 #define timersub(a, b, r) do {\
49 (r)->tv_sec = (a)->tv_sec - (b)->tv_sec;\
50 (r)->tv_usec = (a)->tv_usec - (b)->tv_usec;\
52 (r)->tv_sec--, (r)->tv_usec += 1000000;\
59 static void debug(const char *format, ...) {
62 vfprintf(stderr, format, ap);
66 static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, size_t len) {
68 if(len < sizeof hdr) {
69 debug("%p %s: short packet (%zu bytes)\n", utcp, dir, len);
73 memcpy(&hdr, pkt, sizeof hdr);
74 fprintf (stderr, "%p %s: len=%zu, src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
84 if(len > sizeof hdr) {
86 for(int i = sizeof hdr; i < len; i++) {
87 const char *data = pkt;
88 debug("%c", data[i] >= 32 ? data[i] : '.');
96 #define print_packet(...)
99 static void set_state(struct utcp_connection *c, enum state state) {
101 if(state == ESTABLISHED)
102 timerclear(&c->conn_timeout);
103 debug("%p new state: %s\n", c->utcp, strstate[state]);
106 static bool fin_wanted(struct utcp_connection *c, uint32_t seq) {
107 if(seq != c->snd.last)
119 static inline void list_connections(struct utcp *utcp) {
120 debug("%p has %d connections:\n", utcp, utcp->nconnections);
121 for(int i = 0; i < utcp->nconnections; i++)
122 debug(" %u -> %u state %s\n", utcp->connections[i]->src, utcp->connections[i]->dst, strstate[utcp->connections[i]->state]);
125 static int32_t seqdiff(uint32_t a, uint32_t b) {
130 // TODO: convert to ringbuffers to avoid memmove() operations.
132 // Store data into the buffer
133 static ssize_t buffer_put(struct buffer *buf, const void *data, size_t len) {
134 if(buf->maxsize <= buf->used)
136 if(len > buf->maxsize - buf->used)
137 len = buf->maxsize - buf->used;
138 if(len > buf->size - buf->used) {
139 size_t newsize = buf->size;
142 } while(newsize < buf->used + len);
143 if(newsize > buf->maxsize)
144 newsize = buf->maxsize;
145 char *newdata = realloc(buf->data, newsize);
151 memcpy(buf->data + buf->used, data, len);
156 // Get data from the buffer. data can be NULL.
157 static ssize_t buffer_get(struct buffer *buf, void *data, size_t len) {
161 memcpy(data, buf->data, len);
163 memmove(buf->data, buf->data + len, buf->used - len);
168 // Copy data from the buffer without removing it.
169 static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t len) {
170 if(offset >= buf->used)
172 if(offset + len > buf->used)
173 len = buf->used - offset;
174 memcpy(data, buf->data + offset, len);
178 static bool buffer_init(struct buffer *buf, uint32_t len, uint32_t maxlen) {
179 memset(buf, 0, sizeof *buf);
180 buf->data = malloc(len);
184 buf->maxsize = maxlen;
188 static void buffer_exit(struct buffer *buf) {
190 memset(buf, 0, sizeof *buf);
193 static uint32_t buffer_free(const struct buffer *buf) {
194 return buf->maxsize - buf->used;
197 // Connections are stored in a sorted list.
198 // This gives O(log(N)) lookup time, O(N log(N)) insertion time and O(N) deletion time.
200 static int compare(const void *va, const void *vb) {
203 const struct utcp_connection *a = *(struct utcp_connection **)va;
204 const struct utcp_connection *b = *(struct utcp_connection **)vb;
207 assert(a->src && b->src);
209 int c = (int)a->src - (int)b->src;
212 c = (int)a->dst - (int)b->dst;
216 static struct utcp_connection *find_connection(const struct utcp *utcp, uint16_t src, uint16_t dst) {
217 if(!utcp->nconnections)
219 struct utcp_connection key = {
223 struct utcp_connection **match = bsearch(&keyp, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare);
224 return match ? *match : NULL;
227 static void free_connection(struct utcp_connection *c) {
228 struct utcp *utcp = c->utcp;
229 struct utcp_connection **cp = bsearch(&c, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare);
233 int i = cp - utcp->connections;
234 memmove(cp, cp + 1, (utcp->nconnections - i - 1) * sizeof *cp);
235 utcp->nconnections--;
237 buffer_exit(&c->sndbuf);
241 static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t src, uint16_t dst) {
242 // Check whether this combination of src and dst is free
245 if(find_connection(utcp, src, dst)) {
249 } else { // If src == 0, generate a random port number with the high bit set
250 if(utcp->nconnections >= 32767) {
254 src = rand() | 0x8000;
255 while(find_connection(utcp, src, dst))
259 // Allocate memory for the new connection
261 if(utcp->nconnections >= utcp->nallocated) {
262 if(!utcp->nallocated)
263 utcp->nallocated = 4;
265 utcp->nallocated *= 2;
266 struct utcp_connection **new_array = realloc(utcp->connections, utcp->nallocated * sizeof *utcp->connections);
269 utcp->connections = new_array;
272 struct utcp_connection *c = calloc(1, sizeof *c);
276 if(!buffer_init(&c->sndbuf, DEFAULT_SNDBUFSIZE, DEFAULT_MAXSNDBUFSIZE)) {
281 // Fill in the details
286 c->snd.una = c->snd.iss;
287 c->snd.nxt = c->snd.iss + 1;
288 c->rcv.wnd = utcp->mtu;
289 c->snd.last = c->snd.nxt;
290 c->snd.cwnd = utcp->mtu;
293 // Add it to the sorted list of connections
295 utcp->connections[utcp->nconnections++] = c;
296 qsort(utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare);
301 struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv) {
302 struct utcp_connection *c = allocate_connection(utcp, 0, dst);
313 hdr.seq = c->snd.iss;
315 hdr.wnd = c->rcv.wnd;
319 set_state(c, SYN_SENT);
321 print_packet(utcp, "send", &hdr, sizeof hdr);
322 utcp->send(utcp, &hdr, sizeof hdr);
324 gettimeofday(&c->conn_timeout, NULL);
325 c->conn_timeout.tv_sec += utcp->timeout;
330 void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
331 if(c->reapable || c->state != SYN_RECEIVED) {
332 debug("Error: accept() called on invalid connection %p in state %s\n", c, strstate[c->state]);
336 debug("%p accepted, %p %p\n", c, recv, priv);
339 set_state(c, ESTABLISHED);
342 static void ack(struct utcp_connection *c, bool sendatleastone) {
343 int32_t left = seqdiff(c->snd.last, c->snd.nxt);
344 int32_t cwndleft = c->snd.cwnd - seqdiff(c->snd.nxt, c->snd.una);
354 if(!left && !sendatleastone)
362 pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
366 pkt->hdr.src = c->src;
367 pkt->hdr.dst = c->dst;
368 pkt->hdr.ack = c->rcv.nxt;
369 pkt->hdr.wnd = c->snd.wnd;
374 uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
375 pkt->hdr.seq = c->snd.nxt;
377 buffer_copy(&c->sndbuf, pkt->data, seqdiff(c->snd.nxt, c->snd.una), seglen);
379 c->snd.nxt += seglen;
382 if(seglen && fin_wanted(c, c->snd.nxt)) {
387 print_packet(c->utcp, "send", pkt, sizeof pkt->hdr + seglen);
388 c->utcp->send(c->utcp, pkt, sizeof pkt->hdr + seglen);
394 ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
396 debug("Error: send() called on closed connection %p\n", c);
406 debug("Error: send() called on unconnected connection %p\n", c);
417 debug("Error: send() called on closing connection %p\n", c);
422 // Add data to send buffer
432 len = buffer_put(&c->sndbuf, data, len);
443 static void swap_ports(struct hdr *hdr) {
444 uint16_t tmp = hdr->src;
449 static void retransmit(struct utcp_connection *c) {
450 if(c->state == CLOSED || c->snd.nxt == c->snd.una)
453 struct utcp *utcp = c->utcp;
460 pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
464 pkt->hdr.src = c->src;
465 pkt->hdr.dst = c->dst;
469 // Send our SYN again
470 pkt->hdr.seq = c->snd.iss;
472 pkt->hdr.wnd = c->rcv.wnd;
474 print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
475 utcp->send(utcp, pkt, sizeof pkt->hdr);
480 pkt->hdr.seq = c->snd.nxt;
481 pkt->hdr.ack = c->rcv.nxt;
482 pkt->hdr.ctl = SYN | ACK;
483 print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
484 utcp->send(utcp, pkt, sizeof pkt->hdr);
492 // Send unacked data again.
493 pkt->hdr.seq = c->snd.una;
494 pkt->hdr.ack = c->rcv.nxt;
496 uint32_t len = seqdiff(c->snd.last, c->snd.una);
499 if(fin_wanted(c, c->snd.una + len)) {
503 c->snd.nxt = c->snd.una + len;
504 buffer_copy(&c->sndbuf, pkt->data, 0, len);
505 print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + len);
506 utcp->send(utcp, pkt, sizeof pkt->hdr + len);
513 // We shouldn't need to retransmit anything in this state.
517 timerclear(&c->rtrx_timeout);
525 ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
539 print_packet(utcp, "recv", data, len);
541 // Drop packets smaller than the header
544 if(len < sizeof hdr) {
549 // Make a copy from the potentially unaligned data to a struct hdr
551 memcpy(&hdr, data, sizeof hdr);
555 // Drop packets with an unknown CTL flag
557 if(hdr.ctl & ~(SYN | ACK | RST | FIN)) {
562 // Try to match the packet to an existing connection
564 struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src);
566 // Is it for a new connection?
569 // Ignore RST packets
574 // Is it a SYN packet and are we LISTENing?
576 if(hdr.ctl & SYN && !(hdr.ctl & ACK) && utcp->accept) {
577 // If we don't want to accept it, send a RST back
578 if((utcp->pre_accept && !utcp->pre_accept(utcp, hdr.dst))) {
583 // Try to allocate memory, otherwise send a RST back
584 c = allocate_connection(utcp, hdr.dst, hdr.src);
590 // Return SYN+ACK, go to SYN_RECEIVED state
591 c->snd.wnd = hdr.wnd;
592 c->rcv.irs = hdr.seq;
593 c->rcv.nxt = c->rcv.irs + 1;
594 set_state(c, SYN_RECEIVED);
598 hdr.ack = c->rcv.irs + 1;
599 hdr.seq = c->snd.iss;
601 print_packet(c->utcp, "send", &hdr, sizeof hdr);
602 utcp->send(utcp, &hdr, sizeof hdr);
604 // No, we don't want your packets, send a RST back
612 debug("%p state %s\n", c->utcp, strstate[c->state]);
614 // In case this is for a CLOSED connection, ignore the packet.
615 // TODO: make it so incoming packets can never match a CLOSED connection.
617 if(c->state == CLOSED)
620 // It is for an existing connection.
622 uint32_t prevrcvnxt = c->rcv.nxt;
624 // 1. Drop invalid packets.
626 // 1a. Drop packets that should not happen in our current state.
646 // 1b. Drop packets with a sequence number not in our receive window.
650 if(c->state == SYN_SENT)
653 // TODO: handle packets overlapping c->rcv.nxt.
655 // Only use this when accepting out-of-order packets.
658 acceptable = hdr.seq == c->rcv.nxt;
660 acceptable = (seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt + c->rcv.wnd) < 0);
663 // We don't accept data when the receive window is zero.
666 // Both start and end of packet must be within the receive window
667 acceptable = (seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt + c->rcv.wnd) < 0)
668 || (seqdiff(hdr.seq + len + 1, c->rcv.nxt) >= 0 && seqdiff(hdr.seq + len - 1, c->rcv.nxt + c->rcv.wnd) < 0);
670 if(c->state != SYN_SENT)
671 acceptable = hdr.seq == c->rcv.nxt;
675 debug("Packet not acceptable, %u <= %u + %zu < %u\n", c->rcv.nxt, hdr.seq, len, c->rcv.nxt + c->rcv.wnd);
676 // Ignore unacceptable RST packets.
679 // Otherwise, send an ACK back in the hope things improve.
684 c->snd.wnd = hdr.wnd; // TODO: move below
686 // 1c. Drop packets with an invalid ACK.
687 // ackno should not roll back, and it should also not be bigger than snd.nxt.
689 if(hdr.ctl & ACK && (seqdiff(hdr.ack, c->snd.nxt) > 0 || seqdiff(hdr.ack, c->snd.una) < 0)) {
690 debug("Packet ack seqno out of range, %u %u %u\n", hdr.ack, c->snd.una, c->snd.nxt);
691 // Ignore unacceptable RST packets.
697 // 2. Handle RST packets
704 // The peer has refused our connection.
705 set_state(c, CLOSED);
706 errno = ECONNREFUSED;
713 // We haven't told the application about this connection yet. Silently delete.
722 // The peer has aborted our connection.
723 set_state(c, CLOSED);
733 // As far as the application is concerned, the connection has already been closed.
734 // If it has called utcp_close() already, we can immediately free this connection.
739 // Otherwise, immediately move to the CLOSED state.
740 set_state(c, CLOSED);
750 // 3. Advance snd.una
752 uint32_t advanced = seqdiff(hdr.ack, c->snd.una);
753 prevrcvnxt = c->rcv.nxt;
756 int32_t data_acked = advanced;
763 // TODO: handle FIN as well.
768 assert(data_acked >= 0);
770 int32_t bufused = seqdiff(c->snd.last, c->snd.una);
771 assert(data_acked <= bufused);
774 buffer_get(&c->sndbuf, NULL, data_acked);
776 c->snd.una = hdr.ack;
779 c->snd.cwnd += utcp->mtu;
780 if(c->snd.cwnd > c->sndbuf.maxsize)
781 c->snd.cwnd = c->sndbuf.maxsize;
783 // Check if we have sent a FIN that is now ACKed.
786 if(c->snd.una == c->snd.last)
787 set_state(c, FIN_WAIT_2);
790 if(c->snd.una == c->snd.last) {
791 gettimeofday(&c->conn_timeout, NULL);
792 c->conn_timeout.tv_sec += 60;
793 set_state(c, TIME_WAIT);
803 debug("Triplicate ACK\n");
804 //TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
805 //We do a very simple variant here; reset the nxt pointer to the last acknowledged packet from the peer.
806 //This will cause us to start retransmitting, but at the same speed as the incoming ACKs arrive,
807 //thus preventing a drop in speed.
808 c->snd.nxt = c->snd.una;
816 timerclear(&c->conn_timeout); // It will be set anew in utcp_timeout() if c->snd.una != c->snd.nxt.
817 if(c->snd.una == c->snd.nxt)
818 timerclear(&c->rtrx_timeout);
821 // 5. Process SYN stuff
826 // This is a SYNACK. It should always have ACKed the SYN.
829 c->rcv.irs = hdr.seq;
830 c->rcv.nxt = hdr.seq;
831 set_state(c, ESTABLISHED);
832 // TODO: notify application of this somehow.
842 // Ehm, no. We should never receive a second SYN.
851 // SYN counts as one sequence number
855 // 6. Process new data
857 if(c->state == SYN_RECEIVED) {
858 // This is the ACK after the SYNACK. It should always have ACKed the SYNACK.
862 // Are we still LISTENing?
864 utcp->accept(c, c->src);
866 if(c->state != ESTABLISHED) {
867 set_state(c, CLOSED);
877 // This should never happen.
890 // Ehm no, We should never receive more data after a FIN.
902 rxd = c->recv(c, data, len);
904 // TODO: once we have a receive buffer, handle the application not accepting all data.
910 rxd = len; // Bad application, bad!
918 // 7. Process FIN stuff
924 // This should never happen.
930 set_state(c, CLOSE_WAIT);
933 set_state(c, CLOSING);
936 gettimeofday(&c->conn_timeout, NULL);
937 c->conn_timeout.tv_sec += 60;
938 set_state(c, TIME_WAIT);
944 // Ehm, no. We should never receive a second FIN.
953 // FIN counts as one sequence number
957 // Inform the application that the peer closed the connection.
964 // Now we send something back if:
965 // - we advanced rcv.nxt (ie, we got some data that needs to be ACKed)
966 // -> sendatleastone = true
967 // - or we got an ack, so we should maybe send a bit more data
968 // -> sendatleastone = false
971 ack(c, prevrcvnxt != c->rcv.nxt);
981 hdr.ack = hdr.seq + len;
985 print_packet(utcp, "send", &hdr, sizeof hdr);
986 utcp->send(utcp, &hdr, sizeof hdr);
991 int utcp_shutdown(struct utcp_connection *c, int dir) {
992 debug("%p shutdown %d at %u\n", c ? c->utcp : NULL, dir, c ? c->snd.last : 0);
999 debug("Error: shutdown() called on closed connection %p\n", c);
1004 if(!(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_WR || dir == UTCP_SHUT_RDWR)) {
1009 // TCP does not have a provision for stopping incoming packets.
1010 // The best we can do is to just ignore them.
1011 if(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_RDWR)
1014 // The rest of the code deals with shutting down writes.
1015 if(dir == UTCP_SHUT_RD)
1025 set_state(c, CLOSED);
1030 set_state(c, FIN_WAIT_1);
1036 set_state(c, CLOSING);
1051 int utcp_close(struct utcp_connection *c) {
1052 if(utcp_shutdown(c, SHUT_RDWR))
1060 int utcp_abort(struct utcp_connection *c) {
1067 debug("Error: abort() called on closed connection %p\n", c);
1084 set_state(c, CLOSED);
1092 set_state(c, CLOSED);
1102 hdr.seq = c->snd.nxt;
1107 print_packet(c->utcp, "send", &hdr, sizeof hdr);
1108 c->utcp->send(c->utcp, &hdr, sizeof hdr);
1113 * One call to this function will loop through all connections,
1114 * checking if something needs to be resent or not.
1115 * The return value is the time to the next timeout in milliseconds,
1116 * or maybe a negative value if the timeout is infinite.
1118 struct timeval utcp_timeout(struct utcp *utcp) {
1120 gettimeofday(&now, NULL);
1121 struct timeval next = {now.tv_sec + 3600, now.tv_usec};
1123 for(int i = 0; i < utcp->nconnections; i++) {
1124 struct utcp_connection *c = utcp->connections[i];
1128 if(c->state == CLOSED) {
1130 debug("Reaping %p\n", c);
1137 if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &now, <)) {
1141 c->recv(c, NULL, 0);
1145 if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &now, <)) {
1149 if(c->poll && buffer_free(&c->sndbuf) && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
1150 c->poll(c, buffer_free(&c->sndbuf));
1152 if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
1153 next = c->conn_timeout;
1155 if(c->snd.nxt != c->snd.una) {
1156 c->rtrx_timeout = now;
1157 c->rtrx_timeout.tv_sec++;
1159 timerclear(&c->rtrx_timeout);
1162 if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &next, <))
1163 next = c->rtrx_timeout;
1166 struct timeval diff;
1167 timersub(&next, &now, &diff);
1171 bool utcp_is_active(struct utcp *utcp) {
1175 for(int i = 0; i < utcp->nconnections; i++)
1176 if(utcp->connections[i]->state != CLOSED && utcp->connections[i]->state != TIME_WAIT)
1182 struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv) {
1183 struct utcp *utcp = calloc(1, sizeof *utcp);
1192 utcp->accept = accept;
1193 utcp->pre_accept = pre_accept;
1202 void utcp_exit(struct utcp *utcp) {
1205 for(int i = 0; i < utcp->nconnections; i++) {
1206 if(!utcp->connections[i]->reapable)
1207 debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
1208 buffer_exit(&utcp->connections[i]->sndbuf);
1209 free(utcp->connections[i]);
1211 free(utcp->connections);
1215 uint16_t utcp_get_mtu(struct utcp *utcp) {
1216 return utcp ? utcp->mtu : 0;
1219 void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
1220 // TODO: handle overhead of the header
1225 int utcp_get_user_timeout(struct utcp *u) {
1226 return u ? u->timeout : 0;
1229 void utcp_set_user_timeout(struct utcp *u, int timeout) {
1231 u->timeout = timeout;
1234 size_t utcp_get_sndbuf(struct utcp_connection *c) {
1235 return c ? c->sndbuf.maxsize : 0;
1238 size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
1239 if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
1240 return buffer_free(&c->sndbuf);
1245 void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
1248 c->sndbuf.maxsize = size;
1249 if(c->sndbuf.maxsize != size)
1250 c->sndbuf.maxsize = -1;
1253 bool utcp_get_nodelay(struct utcp_connection *c) {
1254 return c ? c->nodelay : false;
1257 void utcp_set_nodelay(struct utcp_connection *c, bool nodelay) {
1259 c->nodelay = nodelay;
1262 bool utcp_get_keepalive(struct utcp_connection *c) {
1263 return c ? c->keepalive : false;
1266 void utcp_set_keepalive(struct utcp_connection *c, bool keepalive) {
1268 c->keepalive = keepalive;
1271 size_t utcp_get_outq(struct utcp_connection *c) {
1272 return c ? seqdiff(c->snd.nxt, c->snd.una) : 0;
1275 void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
1280 void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
1285 void utcp_set_accept_cb(struct utcp *utcp, utcp_accept_t accept, utcp_pre_accept_t pre_accept) {
1287 utcp->accept = accept;
1288 utcp->pre_accept = pre_accept;