xref: /illumos-gate/usr/src/lib/libnsl/nsl/t_accept.c (revision 86d949f9497332fe19be6b5d711d265eb957439f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
24 /*	  All Rights Reserved  	*/
25 
26 /*
27  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
28  * Use is subject to license terms.
29  */
30 
31 #include "mt.h"
32 #include <stdlib.h>
33 #include <errno.h>
34 #include <unistd.h>
35 #include <stropts.h>
36 #include <sys/stream.h>
37 #define	_SUN_TPI_VERSION 2
38 #include <sys/tihdr.h>
39 #include <sys/timod.h>
40 #include <xti.h>
41 #include <signal.h>
42 #include <syslog.h>
43 #include <assert.h>
44 #include "tx.h"
45 
46 int
47 _tx_accept(
48 	int fd,
49 	int resfd,
50 	const struct t_call *call,
51 	int api_semantics
52 )
53 {
54 	struct T_conn_res *cres;
55 	struct strfdinsert strfdinsert;
56 	int size, retval, sv_errno;
57 	struct _ti_user *tiptr;
58 	struct _ti_user *restiptr;
59 	sigset_t mask;
60 	struct strbuf ctlbuf;
61 	int didalloc;
62 	t_scalar_t conn_res_prim;
63 
64 	if ((tiptr = _t_checkfd(fd, 0, api_semantics)) == NULL)
65 		return (-1);
66 	if ((restiptr = _t_checkfd(resfd, 0, api_semantics)) == NULL)
67 		return (-1);
68 
69 	/*
70 	 * We need to block signals to perform the I_FDINSERT operation
71 	 * (sending T_CONN_RES downstream) which is non-idempotent.
72 	 * Note that sig_mutex_lock() only defers signals, it does not
73 	 * block them, so interruptible syscalls could still get EINTR.
74 	 */
75 	(void) thr_sigsetmask(SIG_SETMASK, &fillset, &mask);
76 	sig_mutex_lock(&tiptr->ti_lock);
77 
78 	if (tiptr->ti_servtype == T_CLTS) {
79 		t_errno = TNOTSUPPORT;
80 		sig_mutex_unlock(&tiptr->ti_lock);
81 		(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
82 		return (-1);
83 	}
84 
85 	if (_T_IS_XTI(api_semantics)) {
86 		/*
87 		 * User level state verification only done for XTI
88 		 * because doing for TLI may break existing applications
89 		 *
90 		 * For fd == resfd, state should be T_INCON
91 		 * For fd != resfd,
92 		 *	    fd state should be T_INCON
93 		 *	    resfd state should be T_IDLE (bound endpoint) or
94 		 *	    it can be T_UNBND. The T_UNBND case is not (yet?)
95 		 *	    allowed in the published XTI spec but fixed by the
96 		 *	    corrigenda.
97 		 */
98 		if ((fd == resfd && tiptr->ti_state != T_INCON) ||
99 		    (fd != resfd &&
100 			((tiptr->ti_state != T_INCON) ||
101 		    !(restiptr->ti_state == T_IDLE ||
102 			restiptr->ti_state == T_UNBND)))) {
103 			t_errno = TOUTSTATE;
104 			sig_mutex_unlock(&tiptr->ti_lock);
105 			(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
106 			return (-1);
107 		}
108 
109 		/*
110 		 * XTI says:
111 		 * If fd != resfd, and a resfd bound to a protocol address is
112 		 * passed, then it better not have a qlen > 0.
113 		 * That is, an endpoint bound as if it will be a listener
114 		 * cannot be used as an acceptor.
115 		 */
116 		if (fd != resfd && restiptr->ti_state == T_IDLE &&
117 		    restiptr->ti_qlen > 0) {
118 			t_errno = TRESQLEN;
119 			sig_mutex_unlock(&tiptr->ti_lock);
120 			(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
121 			return (-1);
122 		}
123 
124 		if (fd == resfd && tiptr->ti_ocnt > 1) {
125 			t_errno = TINDOUT;
126 			sig_mutex_unlock(&tiptr->ti_lock);
127 			(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
128 			return (-1);
129 		}
130 
131 		/*
132 		 * Note: TRESADDR error is specified by XTI. It happens
133 		 * when resfd is bound and fd and resfd are not BOUND to
134 		 * the same protocol address. TCP obviously does allow
135 		 * two endpoints to bind to the same address. Why is the
136 		 * need for this error considering there is an address switch
137 		 * that can be done for the endpoint at accept time ? Go
138 		 * figure and ask the XTI folks.
139 		 * We interpret this to be a transport specific error condition
140 		 * to be be coveyed by the transport provider in T_ERROR_ACK
141 		 * to T_CONN_RES on transports that allow two endpoints to
142 		 * be bound to the same address and have trouble with the
143 		 * idea of accepting connections on a resfd that has a qlen > 0
144 		 */
145 	}
146 
147 	if (fd != resfd) {
148 		if ((retval = ioctl(resfd, I_NREAD, &size)) < 0) {
149 			sv_errno = errno;
150 
151 			t_errno = TSYSERR;
152 			sig_mutex_unlock(&tiptr->ti_lock);
153 			(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
154 			errno = sv_errno;
155 			return (-1);
156 		}
157 		if (retval > 0) {
158 			t_errno = TBADF;
159 			sig_mutex_unlock(&tiptr->ti_lock);
160 			(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
161 			return (-1);
162 		}
163 	}
164 
165 	/*
166 	 * Acquire ctlbuf for use in sending/receiving control part
167 	 * of the message.
168 	 */
169 	if (_t_acquire_ctlbuf(tiptr, &ctlbuf, &didalloc) < 0) {
170 		sv_errno = errno;
171 		sig_mutex_unlock(&tiptr->ti_lock);
172 		(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
173 		errno = sv_errno;
174 		return (-1);
175 	}
176 
177 	/*
178 	 * In Unix98 t_accept() need not return [TLOOK] if connect/disconnect
179 	 * indications are present. TLI and Unix95 need to return error.
180 	 */
181 	if (_T_API_VER_LT(api_semantics, TX_XTI_XNS5_API)) {
182 		if (_t_is_event(fd, tiptr) < 0)
183 			goto err_out;
184 	}
185 
186 	/* LINTED pointer cast */
187 	cres = (struct T_conn_res *)ctlbuf.buf;
188 	cres->OPT_length = call->opt.len;
189 	cres->OPT_offset = 0;
190 	cres->SEQ_number = call->sequence;
191 	if ((restiptr->ti_flags & V_ACCEPTOR_ID) != 0) {
192 		cres->ACCEPTOR_id = restiptr->acceptor_id;
193 		cres->PRIM_type = conn_res_prim = T_CONN_RES;
194 	} else {
195 		/* I_FDINSERT should use O_T_CONN_RES. */
196 		cres->ACCEPTOR_id = 0;
197 		cres->PRIM_type = conn_res_prim = O_T_CONN_RES;
198 	}
199 
200 	size = (int)sizeof (struct T_conn_res);
201 
202 	if (call->opt.len) {
203 		if (_t_aligned_copy(&ctlbuf, call->opt.len, size,
204 		    call->opt.buf, &cres->OPT_offset) < 0) {
205 			/*
206 			 * Aligned copy will overflow buffer allocated based
207 			 * transport maximum options length.
208 			 * return error.
209 			 */
210 			t_errno = TBADOPT;
211 			goto err_out;
212 		}
213 		size = cres->OPT_offset + cres->OPT_length;
214 	}
215 
216 	if (call->udata.len) {
217 		if ((tiptr->ti_cdatasize == T_INVALID /* -2 */) ||
218 		    ((tiptr->ti_cdatasize != T_INFINITE /* -1 */) &&
219 			(call->udata.len > (uint32_t)tiptr->ti_cdatasize))) {
220 			/*
221 			 * user data not valid with connect or it
222 			 * exceeds the limits specified by the transport
223 			 * provider
224 			 */
225 			t_errno = TBADDATA;
226 			goto err_out;
227 		}
228 	}
229 
230 
231 	ctlbuf.len = size;
232 
233 	/*
234 	 * Assumes signals are blocked so putmsg() will not block
235 	 * indefinitely
236 	 */
237 	if ((restiptr->ti_flags & V_ACCEPTOR_ID) != 0) {
238 		/*
239 		 * Assumes signals are blocked so putmsg() will not block
240 		 * indefinitely
241 		 */
242 		if (putmsg(fd, &ctlbuf,
243 		    (struct strbuf *)(call->udata.len? &call->udata: NULL), 0) <
244 		    0) {
245 			if (errno == EAGAIN)
246 				t_errno = TFLOW;
247 			else
248 				t_errno = TSYSERR;
249 			goto err_out;
250 		}
251 	} else {
252 		strfdinsert.ctlbuf.maxlen = ctlbuf.maxlen;
253 		strfdinsert.ctlbuf.len = ctlbuf.len;
254 		strfdinsert.ctlbuf.buf = ctlbuf.buf;
255 
256 		strfdinsert.databuf.maxlen = call->udata.maxlen;
257 		strfdinsert.databuf.len =
258 		    (call->udata.len? call->udata.len: -1);
259 		strfdinsert.databuf.buf = call->udata.buf;
260 		strfdinsert.fildes = resfd;
261 		strfdinsert.offset = (int)sizeof (t_scalar_t);
262 		strfdinsert.flags = 0;		/* could be EXPEDITED also */
263 
264 		if (ioctl(fd, I_FDINSERT, &strfdinsert) < 0) {
265 			if (errno == EAGAIN)
266 				t_errno = TFLOW;
267 			else
268 				t_errno = TSYSERR;
269 			goto err_out;
270 		}
271 	}
272 
273 	if (_t_is_ok(fd, tiptr, conn_res_prim) < 0) {
274 		/*
275 		 * At the TPI level, the error returned in a T_ERROR_ACK
276 		 * received in response to a T_CONN_RES for a listener and
277 		 * acceptor endpoints not being the same kind of endpoints
278 		 * has changed to a new t_errno code introduced with
279 		 * XTI (TPROVMISMATCH). We need to adjust TLI error code
280 		 * to be same as before.
281 		 */
282 		if (_T_IS_TLI(api_semantics) && t_errno == TPROVMISMATCH) {
283 			/* TLI only */
284 			t_errno = TBADF;
285 		}
286 		goto err_out;
287 	}
288 
289 	if (tiptr->ti_ocnt == 1) {
290 		if (fd == resfd) {
291 			_T_TX_NEXTSTATE(T_ACCEPT1, tiptr,
292 				"t_accept: invalid state event T_ACCEPT1");
293 		} else {
294 			_T_TX_NEXTSTATE(T_ACCEPT2, tiptr,
295 				"t_accept: invalid state event T_ACCEPT2");
296 			/*
297 			 * XXX Here we lock the resfd lock also. This
298 			 * is an instance of holding two locks without
299 			 * any enforcement of a locking hiararchy.
300 			 * There is potential for deadlock in incorrect
301 			 * or buggy programs here but this is the safer
302 			 * choice in this case. Correct programs will not
303 			 * deadlock.
304 			 */
305 			sig_mutex_lock(&restiptr->ti_lock);
306 			_T_TX_NEXTSTATE(T_PASSCON, restiptr,
307 				"t_accept: invalid state event T_PASSCON");
308 			sig_mutex_unlock(&restiptr->ti_lock);
309 		}
310 	} else {
311 		_T_TX_NEXTSTATE(T_ACCEPT3, tiptr,
312 				"t_accept: invalid state event T_ACCEPT3");
313 		if (fd != resfd)
314 			sig_mutex_lock(&restiptr->ti_lock);
315 		_T_TX_NEXTSTATE(T_PASSCON, restiptr,
316 				"t_accept: invalid state event T_PASSCON");
317 		if (fd != resfd)
318 			sig_mutex_unlock(&restiptr->ti_lock);
319 	}
320 
321 	tiptr->ti_ocnt--;
322 	tiptr->ti_flags &= ~TX_TQFULL_NOTIFIED;
323 
324 	/*
325 	 * Update attributes which may have been negotiated during
326 	 * connection establishment for protocols where we suspect
327 	 * such negotiation is likely (e.g. OSI). We do not do it for
328 	 * all endpoints for performance reasons. Also, this code is
329 	 * deliberately done after user level state changes so even
330 	 * the (unlikely) failure case reflects a connected endpoint.
331 	 */
332 	if (restiptr->ti_tsdusize != 0) {
333 		if (_t_do_postconn_sync(resfd, restiptr) < 0)
334 			goto err_out;
335 	}
336 
337 	if (didalloc)
338 		free(ctlbuf.buf);
339 	else
340 		tiptr->ti_ctlbuf = ctlbuf.buf;
341 	sig_mutex_unlock(&tiptr->ti_lock);
342 	(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
343 	return (0);
344 	/* NOTREACHED */
345 err_out:
346 	sv_errno = errno;
347 	if (didalloc)
348 		free(ctlbuf.buf);
349 	else
350 		tiptr->ti_ctlbuf = ctlbuf.buf;
351 	sig_mutex_unlock(&tiptr->ti_lock);
352 	(void) thr_sigsetmask(SIG_SETMASK, &mask, NULL);
353 	errno = sv_errno;
354 	return (-1);
355 }
356