[apple/xnu.git] / bsd / net / classq / classq_util.c

/*
 * Copyright (c) 2007-2011 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 * Copyright (c) 1991-1997 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Network Research
 *      Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/random.h>
#include <sys/kernel_types.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/net_osdep.h>
#include <net/classq/classq.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#if INET6
#include <netinet/ip6.h>
#endif
#include <netinet/tcp.h>
#include <netinet/udp.h>

#include <libkern/libkern.h>

/*
 * read and write diffserv field in IPv4 or IPv6 header
 */
u_int8_t
read_dsfield(struct mbuf *m, struct pf_mtag *t)
{
	struct mbuf *m0;
	u_int8_t ds_field = 0;

	if (t->pftag_hdr == NULL ||
	    !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
		return ((u_int8_t)0);

	/* verify that hdr is within the mbuf data */
	for (m0 = m; m0 != NULL; m0 = m0->m_next)
		if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
		    ((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
			break;
	if (m0 == NULL) {
		/* ick, tag info is stale */
		printf("%s: can't locate header!\n", __func__);
		return ((u_int8_t)0);
	}

	if (t->pftag_flags & PF_TAG_HDR_INET) {
		struct ip *ip = (struct ip *)(void *)t->pftag_hdr;

		if (((uintptr_t)ip + sizeof (*ip)) >
		    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
			return (0);		/* out of bounds */

		if (ip->ip_v != 4)
			return ((u_int8_t)0);	/* version mismatch! */
		ds_field = ip->ip_tos;
	}
#if INET6
	else if (t->pftag_flags & PF_TAG_HDR_INET6) {
		struct ip6_hdr *ip6 = (struct ip6_hdr *)(void *)t->pftag_hdr;
		u_int32_t flowlabel;

		if (((uintptr_t)ip6 + sizeof (*ip6)) >
		    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
			return (0);		/* out of bounds */

		flowlabel = ntohl(ip6->ip6_flow);
		if ((flowlabel >> 28) != 6)
			return ((u_int8_t)0);	/* version mismatch! */
		ds_field = (flowlabel >> 20) & 0xff;
	}
#endif
	return (ds_field);
}

void
write_dsfield(struct mbuf *m, struct pf_mtag *t, u_int8_t dsfield)
{
	struct mbuf *m0;

	if (t->pftag_hdr == NULL ||
	    !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
		return;

	/* verify that hdr is within the mbuf data */
	for (m0 = m; m0 != NULL; m0 = m0->m_next)
		if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
		    ((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
			break;
	if (m0 == NULL) {
		/* ick, tag info is stale */
		printf("%s: can't locate header!\n", __func__);
		return;
	}

	if (t->pftag_flags & PF_TAG_HDR_INET) {
		struct ip *ip = (struct ip *)(void *)t->pftag_hdr;
		u_int8_t old;
		int32_t sum;

		if (((uintptr_t)ip + sizeof (*ip)) >
		    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
			return;		/* out of bounds */

		if (ip->ip_v != 4)
			return;		/* version mismatch! */
		old = ip->ip_tos;
		dsfield |= old & 3;	/* leave CU bits */
		if (old == dsfield)
			return;
		ip->ip_tos = dsfield;
		/*
		 * update checksum (from RFC1624)
		 *	   HC' = ~(~HC + ~m + m')
		 */
		sum = ~ntohs(ip->ip_sum) & 0xffff;
		sum += 0xff00 + (~old & 0xff) + dsfield;
		sum = (sum >> 16) + (sum & 0xffff);
		sum += (sum >> 16);  /* add carry */

		ip->ip_sum = htons(~sum & 0xffff);
	}
#if INET6
	else if (t->pftag_flags & PF_TAG_HDR_INET6) {
		struct ip6_hdr *ip6 = (struct ip6_hdr *)t->pftag_hdr;
		u_int32_t flowlabel;

		if (((uintptr_t)ip6 + sizeof (*ip6)) >
		    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
			return;		/* out of bounds */

		flowlabel = ntohl(ip6->ip6_flow);
		if ((flowlabel >> 28) != 6)
			return;		/* version mismatch! */
		flowlabel = (flowlabel & 0xf03fffff) | (dsfield << 20);
		ip6->ip6_flow = htonl(flowlabel);
	}
#endif
}

/*
 * try to mark CE bit to the packet.
 *    returns 1 if successfully marked, 0 otherwise.
 */
int
mark_ecn(struct mbuf *m, struct pf_mtag *t, int flags)
{
	struct mbuf	*m0;
	void		*hdr;
	int		af;

	if ((hdr = t->pftag_hdr) == NULL ||
	    !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
		return (0);

	/* verify that hdr is within the mbuf data */
	for (m0 = m; m0 != NULL; m0 = m0->m_next)
		if (((caddr_t)hdr >= m0->m_data) &&
		    ((caddr_t)hdr < m0->m_data + m0->m_len))
			break;
	if (m0 == NULL) {
		/* ick, tag info is stale */
		printf("%s: can't locate header!\n", __func__);
		return (0);
	}

	if (t->pftag_flags & PF_TAG_HDR_INET)
		af = AF_INET;
	else if (t->pftag_flags & PF_TAG_HDR_INET6)
		af = AF_INET6;
	else
		af = AF_UNSPEC;

	switch (af) {
	case AF_INET:
		if (flags & CLASSQF_ECN4) {	/* REDF_ECN4 == BLUEF_ECN4 */
			struct ip *ip = hdr;
			u_int8_t otos;
			int sum;

			if (((uintptr_t)ip + sizeof (*ip)) >
			    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
				return (0);	/* out of bounds */

			if (ip->ip_v != 4)
				return (0);	/* version mismatch! */
			if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
				return (0);	/* not-ECT */
			if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
				return (1);	/* already marked */

			/*
			 * ecn-capable but not marked,
			 * mark CE and update checksum
			 */
			otos = ip->ip_tos;
			ip->ip_tos |= IPTOS_ECN_CE;
			/*
			 * update checksum (from RFC1624)
			 *	   HC' = ~(~HC + ~m + m')
			 */
			sum = ~ntohs(ip->ip_sum) & 0xffff;
			sum += (~otos & 0xffff) + ip->ip_tos;
			sum = (sum >> 16) + (sum & 0xffff);
			sum += (sum >> 16);  /* add carry */
			ip->ip_sum = htons(~sum & 0xffff);
			return (1);
		}
		break;
#if INET6
	case AF_INET6:
		if (flags & CLASSQF_ECN6) {	/* REDF_ECN6 == BLUEF_ECN6 */
			struct ip6_hdr *ip6 = hdr;
			u_int32_t flowlabel;

			if (((uintptr_t)ip6 + sizeof (*ip6)) >
			    ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
				return (0);	/* out of bounds */

			flowlabel = ntohl(ip6->ip6_flow);
			if ((flowlabel >> 28) != 6)
				return (0);	/* version mismatch! */
			if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
			    (IPTOS_ECN_NOTECT << 20))
				return (0);	/* not-ECT */
			if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
			    (IPTOS_ECN_CE << 20))
				return (1);	/* already marked */
			/*
			 * ecn-capable but not marked,  mark CE
			 */
			flowlabel |= (IPTOS_ECN_CE << 20);
			ip6->ip6_flow = htonl(flowlabel);
			return (1);
		}
		break;
#endif  /* INET6 */
	}

	/* not marked */
	return (0);
}
Commit	Line	Data
316670eb A	1	/*
	2	* Copyright (c) 2007-2011 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	/*
	30	* Copyright (c) 1991-1997 Regents of the University of California.
	31	* All rights reserved.
	32	*
	33	* Redistribution and use in source and binary forms, with or without
	34	* modification, are permitted provided that the following conditions
	35	* are met:
	36	* 1. Redistributions of source code must retain the above copyright
	37	* notice, this list of conditions and the following disclaimer.
	38	* 2. Redistributions in binary form must reproduce the above copyright
	39	* notice, this list of conditions and the following disclaimer in the
	40	* documentation and/or other materials provided with the distribution.
	41	* 3. All advertising materials mentioning features or use of this software
	42	* must display the following acknowledgement:
	43	* This product includes software developed by the Network Research
	44	* Group at Lawrence Berkeley Laboratory.
	45	* 4. Neither the name of the University nor of the Laboratory may be used
	46	* to endorse or promote products derived from this software without
	47	* specific prior written permission.
	48	*
	49	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	50	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	51	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	52	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	53	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	54	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	55	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	56	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	57	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	58	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	59	* SUCH DAMAGE.
	60	*/
	61
	62	#include <sys/cdefs.h>
	63	#include <sys/param.h>
	64	#include <sys/mbuf.h>
65	#include <sys/errno.h>
66	#include <sys/random.h>
67	#include <sys/kernel_types.h>
68	#include <sys/sysctl.h>
69
70	#include <net/if.h>
71	#include <net/net_osdep.h>
72	#include <net/classq/classq.h>
73
74	#include <netinet/in.h>
75	#include <netinet/in_systm.h>
76	#include <netinet/ip.h>
77	#if INET6
78	#include <netinet/ip6.h>
79	#endif
80	#include <netinet/tcp.h>
81	#include <netinet/udp.h>
82
83	#include <libkern/libkern.h>
84
85	/*
86	* read and write diffserv field in IPv4 or IPv6 header
87	*/
88	u_int8_t
89	read_dsfield(struct mbuf m, struct pf_mtag t)
90	{
91	struct mbuf *m0;
92	u_int8_t ds_field = 0;
93
94	if (t->pftag_hdr == NULL \|\|
95	!(t->pftag_flags & (PF_TAG_HDR_INET\|PF_TAG_HDR_INET6)))
96	return ((u_int8_t)0);
97
98	/* verify that hdr is within the mbuf data */
99	for (m0 = m; m0 != NULL; m0 = m0->m_next)
100	if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
101	((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
102	break;
103	if (m0 == NULL) {
104	/* ick, tag info is stale */
105	printf("%s: can't locate header!\n", __func__);
106	return ((u_int8_t)0);
107	}
108
109	if (t->pftag_flags & PF_TAG_HDR_INET) {
110	struct ip ip = (struct ip )(void *)t->pftag_hdr;
111
112	if (((uintptr_t)ip + sizeof (*ip)) >
113	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
114	return (0); /* out of bounds */
115
116	if (ip->ip_v != 4)
117	return ((u_int8_t)0); /* version mismatch! */
118	ds_field = ip->ip_tos;
119	}
120	#if INET6
121	else if (t->pftag_flags & PF_TAG_HDR_INET6) {
122	struct ip6_hdr ip6 = (struct ip6_hdr )(void *)t->pftag_hdr;
123	u_int32_t flowlabel;
124
125	if (((uintptr_t)ip6 + sizeof (*ip6)) >
126	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
127	return (0); /* out of bounds */
128
129	flowlabel = ntohl(ip6->ip6_flow);
130	if ((flowlabel >> 28) != 6)
131	return ((u_int8_t)0); /* version mismatch! */
132	ds_field = (flowlabel >> 20) & 0xff;
133	}
134	#endif
135	return (ds_field);
136	}
137
138	void
139	write_dsfield(struct mbuf m, struct pf_mtag t, u_int8_t dsfield)
140	{
141	struct mbuf *m0;
142
143	if (t->pftag_hdr == NULL \|\|
144	!(t->pftag_flags & (PF_TAG_HDR_INET\|PF_TAG_HDR_INET6)))
145	return;
146
147	/* verify that hdr is within the mbuf data */
148	for (m0 = m; m0 != NULL; m0 = m0->m_next)
149	if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
150	((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
151	break;
152	if (m0 == NULL) {
153	/* ick, tag info is stale */
154	printf("%s: can't locate header!\n", __func__);
155	return;
156	}
157
158	if (t->pftag_flags & PF_TAG_HDR_INET) {
159	struct ip ip = (struct ip )(void *)t->pftag_hdr;
160	u_int8_t old;
161	int32_t sum;
162
163	if (((uintptr_t)ip + sizeof (*ip)) >
164	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
165	return; /* out of bounds */
166
167	if (ip->ip_v != 4)
168	return; /* version mismatch! */
169	old = ip->ip_tos;
170	dsfield \|= old & 3; /* leave CU bits */
171	if (old == dsfield)
172	return;
173	ip->ip_tos = dsfield;
174	/*
175	* update checksum (from RFC1624)
176	* HC' = ~(~HC + ~m + m')
177	*/
178	sum = ~ntohs(ip->ip_sum) & 0xffff;
179	sum += 0xff00 + (~old & 0xff) + dsfield;
180	sum = (sum >> 16) + (sum & 0xffff);
181	sum += (sum >> 16); /* add carry */
182
183	ip->ip_sum = htons(~sum & 0xffff);
184	}
185	#if INET6
186	else if (t->pftag_flags & PF_TAG_HDR_INET6) {
187	struct ip6_hdr ip6 = (struct ip6_hdr )t->pftag_hdr;
188	u_int32_t flowlabel;
189
190	if (((uintptr_t)ip6 + sizeof (*ip6)) >
191	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
192	return; /* out of bounds */
193
194	flowlabel = ntohl(ip6->ip6_flow);
195	if ((flowlabel >> 28) != 6)
196	return; /* version mismatch! */
197	flowlabel = (flowlabel & 0xf03fffff) \| (dsfield << 20);
198	ip6->ip6_flow = htonl(flowlabel);
199	}
200	#endif
201	}
202
203	/*
204	* try to mark CE bit to the packet.
205	* returns 1 if successfully marked, 0 otherwise.
206	*/
207	int
208	mark_ecn(struct mbuf m, struct pf_mtag t, int flags)
209	{
210	struct mbuf *m0;
211	void *hdr;
212	int af;
213
214	if ((hdr = t->pftag_hdr) == NULL \|\|
215	!(t->pftag_flags & (PF_TAG_HDR_INET\|PF_TAG_HDR_INET6)))
216	return (0);
217
218	/* verify that hdr is within the mbuf data */
219	for (m0 = m; m0 != NULL; m0 = m0->m_next)
220	if (((caddr_t)hdr >= m0->m_data) &&
221	((caddr_t)hdr < m0->m_data + m0->m_len))
222	break;
223	if (m0 == NULL) {
224	/* ick, tag info is stale */
225	printf("%s: can't locate header!\n", __func__);
226	return (0);
227	}
228
229	if (t->pftag_flags & PF_TAG_HDR_INET)
230	af = AF_INET;
231	else if (t->pftag_flags & PF_TAG_HDR_INET6)
232	af = AF_INET6;
233	else
234	af = AF_UNSPEC;
235
236	switch (af) {
237	case AF_INET:
238	if (flags & CLASSQF_ECN4) { /* REDF_ECN4 == BLUEF_ECN4 */
239	struct ip *ip = hdr;
240	u_int8_t otos;
241	int sum;
242
243	if (((uintptr_t)ip + sizeof (*ip)) >
244	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
245	return (0); /* out of bounds */
246
247	if (ip->ip_v != 4)
248	return (0); /* version mismatch! */
249	if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
250	return (0); /* not-ECT */
251	if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
252	return (1); /* already marked */
253
254	/*
255	* ecn-capable but not marked,
256	* mark CE and update checksum
257	*/
258	otos = ip->ip_tos;
259	ip->ip_tos \|= IPTOS_ECN_CE;
260	/*
261	* update checksum (from RFC1624)
262	* HC' = ~(~HC + ~m + m')
263	*/
264	sum = ~ntohs(ip->ip_sum) & 0xffff;
265	sum += (~otos & 0xffff) + ip->ip_tos;
266	sum = (sum >> 16) + (sum & 0xffff);
267	sum += (sum >> 16); /* add carry */
268	ip->ip_sum = htons(~sum & 0xffff);
269	return (1);
270	}
271	break;
272	#if INET6
273	case AF_INET6:
274	if (flags & CLASSQF_ECN6) { /* REDF_ECN6 == BLUEF_ECN6 */
275	struct ip6_hdr *ip6 = hdr;
276	u_int32_t flowlabel;
277
278	if (((uintptr_t)ip6 + sizeof (*ip6)) >
279	((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
280	return (0); /* out of bounds */
281
282	flowlabel = ntohl(ip6->ip6_flow);
283	if ((flowlabel >> 28) != 6)
284	return (0); /* version mismatch! */
285	if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
286	(IPTOS_ECN_NOTECT << 20))
287	return (0); /* not-ECT */
288	if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
289	(IPTOS_ECN_CE << 20))
290	return (1); /* already marked */
291	/*
292	* ecn-capable but not marked, mark CE
293	*/
294	flowlabel \|= (IPTOS_ECN_CE << 20);
295	ip6->ip6_flow = htonl(flowlabel);
296	return (1);
297	}
298	break;
299	#endif /* INET6 */
300	}
301
302	/* not marked */
303	return (0);
304	}