xref: /illumos-gate/usr/src/uts/common/inet/ip_impl.h (revision fab254e2b865295c3dd79c791650a3161d99e196)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #ifndef	_INET_IP_IMPL_H
27 #define	_INET_IP_IMPL_H
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 /*
32  * IP implementation private declarations.  These interfaces are
33  * used to build the IP module and are not meant to be accessed
34  * by any modules except IP itself.  They are undocumented and are
35  * subject to change without notice.
36  */
37 
38 #ifdef	__cplusplus
39 extern "C" {
40 #endif
41 
42 #ifdef _KERNEL
43 
44 #include <sys/sdt.h>
45 
46 #define	IP_MOD_ID		5701
47 
48 #ifdef	_BIG_ENDIAN
49 #define	IP_HDR_CSUM_TTL_ADJUST	256
50 #define	IP_TCP_CSUM_COMP	IPPROTO_TCP
51 #define	IP_UDP_CSUM_COMP	IPPROTO_UDP
52 #else
53 #define	IP_HDR_CSUM_TTL_ADJUST	1
54 #define	IP_TCP_CSUM_COMP	(IPPROTO_TCP << 8)
55 #define	IP_UDP_CSUM_COMP	(IPPROTO_UDP << 8)
56 #endif
57 
58 #define	TCP_CHECKSUM_OFFSET	16
59 #define	TCP_CHECKSUM_SIZE	2
60 
61 #define	UDP_CHECKSUM_OFFSET	6
62 #define	UDP_CHECKSUM_SIZE	2
63 
64 #define	IPH_TCPH_CHECKSUMP(ipha, hlen)	\
65 	((uint16_t *)(((uchar_t *)(ipha)) + ((hlen) + TCP_CHECKSUM_OFFSET)))
66 
67 #define	IPH_UDPH_CHECKSUMP(ipha, hlen)	\
68 	((uint16_t *)(((uchar_t *)(ipha)) + ((hlen) + UDP_CHECKSUM_OFFSET)))
69 
70 #define	ILL_HCKSUM_CAPABLE(ill)		\
71 	(((ill)->ill_capabilities & ILL_CAPAB_HCKSUM) != 0)
72 /*
73  * Macro that performs software checksum calculation on the IP header.
74  */
75 #define	IP_HDR_CKSUM(ipha, sum, v_hlen_tos_len, ttl_protocol) {		\
76 	(sum) += (ttl_protocol) + (ipha)->ipha_ident +			\
77 	    ((v_hlen_tos_len) >> 16) +					\
78 	    ((v_hlen_tos_len) & 0xFFFF) +				\
79 	    (ipha)->ipha_fragment_offset_and_flags;			\
80 	(sum) = (((sum) & 0xFFFF) + ((sum) >> 16));			\
81 	(sum) = ~((sum) + ((sum) >> 16));				\
82 	(ipha)->ipha_hdr_checksum = (uint16_t)(sum);			\
83 }
84 
85 #define	IS_IP_HDR_HWCKSUM(ipsec, mp, ill)				\
86 	((!ipsec) && (DB_CKSUMFLAGS(mp) & HCK_IPV4_HDRCKSUM) &&		\
87 	ILL_HCKSUM_CAPABLE(ill) && dohwcksum)
88 
89 /*
90  * This macro acts as a wrapper around IP_CKSUM_XMIT_FAST, and it performs
91  * several checks on the IRE and ILL (among other things) in order to see
92  * whether or not hardware checksum offload is allowed for the outgoing
93  * packet.  It assumes that the caller has held a reference to the IRE.
94  */
95 #define	IP_CKSUM_XMIT(ill, ire, mp, ihp, up, proto, start, end,		\
96 	    max_frag, ipsec_len, pseudo) {				\
97 	uint32_t _hck_flags;						\
98 	/*								\
99 	 * We offload checksum calculation to hardware when IPsec isn't	\
100 	 * present and if fragmentation isn't required.  We also check	\
101 	 * if M_DATA fastpath is safe to be used on the	corresponding	\
102 	 * IRE; this check is performed without grabbing ire_lock but	\
103 	 * instead by holding a reference to it.  This is sufficient	\
104 	 * for IRE_CACHE; for IRE_BROADCAST on non-Ethernet links, the	\
105 	 * DL_NOTE_FASTPATH_FLUSH indication could come up from the	\
106 	 * driver and trigger the IRE (hence fp_mp) deletion.  This is	\
107 	 * why only IRE_CACHE type is eligible for offload.		\
108 	 *								\
109 	 * The presense of IP options also forces the network stack to	\
110 	 * calculate the checksum in software.  This is because:	\
111 	 *								\
112 	 * Wrap around: certain partial-checksum NICs (eri, ce) limit	\
113 	 * the size of "start offset" width to 6-bit.  This effectively	\
114 	 * sets the largest value of the offset to 64-bytes, starting	\
115 	 * from the MAC header.  When the cumulative MAC and IP headers	\
116 	 * exceed such limit, the offset will wrap around.  This causes	\
117 	 * the checksum to be calculated at the wrong place.		\
118 	 *								\
119 	 * IPv4 source routing: none of the full-checksum capable NICs	\
120 	 * is capable of correctly handling the	IPv4 source-routing	\
121 	 * option for purposes of calculating the pseudo-header; the	\
122 	 * actual destination is different from the destination in the	\
123 	 * header which is that of the next-hop.  (This case may not be	\
124 	 * true for NICs which can parse IPv6 extension headers, but	\
125 	 * we choose to simplify the implementation by not offloading	\
126 	 * checksum when they are present.)				\
127 	 *								\
128 	 */								\
129 	if ((ill) != NULL && ILL_HCKSUM_CAPABLE(ill) &&			\
130 	    !((ire)->ire_flags & RTF_MULTIRT) &&			\
131 	    (!((ire)->ire_type & IRE_BROADCAST) ||			\
132 	    (ill)->ill_type == IFT_ETHER) &&			\
133 	    (ipsec_len) == 0 &&						\
134 	    (((ire)->ire_ipversion == IPV4_VERSION &&			\
135 	    (start) == IP_SIMPLE_HDR_LENGTH &&				\
136 	    ((ire)->ire_nce != NULL &&					\
137 	    (ire)->ire_nce->nce_fp_mp != NULL &&	\
138 	    MBLKHEAD(mp) >= MBLKL((ire)->ire_nce->nce_fp_mp))) ||	\
139 	    ((ire)->ire_ipversion == IPV6_VERSION &&			\
140 	    (start) == IPV6_HDR_LEN &&					\
141 	    (ire)->ire_nce->nce_fp_mp != NULL &&			\
142 	    MBLKHEAD(mp) >= MBLKL((ire)->ire_nce->nce_fp_mp))) &&	\
143 	    (max_frag) >= (uint_t)((end) + (ipsec_len)) &&		\
144 	    dohwcksum) {						\
145 		_hck_flags = (ill)->ill_hcksum_capab->ill_hcksum_txflags; \
146 	} else {							\
147 		_hck_flags = 0;						\
148 	}								\
149 	IP_CKSUM_XMIT_FAST((ire)->ire_ipversion, _hck_flags, mp, ihp,	\
150 	    up, proto, start, end, pseudo);				\
151 }
152 
153 /*
154  * Based on the device capabilities, this macro either marks an outgoing
155  * packet with hardware checksum offload information or calculate the
156  * checksum in software.  If the latter is performed, the checksum field
157  * of the dblk is cleared; otherwise it will be non-zero and contain the
158  * necessary flag(s) for the driver.
159  */
160 #define	IP_CKSUM_XMIT_FAST(ipver, hck_flags, mp, ihp, up, proto, start,	\
161 	    end, pseudo) {						\
162 	uint32_t _sum;							\
163 	/*								\
164 	 * Underlying interface supports hardware checksum offload for	\
165 	 * the payload; leave the payload checksum for the hardware to	\
166 	 * calculate.  N.B: We only need to set up checksum info on the	\
167 	 * first mblk.							\
168 	 */								\
169 	DB_CKSUMFLAGS(mp) = 0;						\
170 	if (((ipver) == IPV4_VERSION &&					\
171 	    ((hck_flags) & HCKSUM_INET_FULL_V4)) ||			\
172 	    ((ipver) == IPV6_VERSION &&					\
173 	    ((hck_flags) & HCKSUM_INET_FULL_V6))) {			\
174 		/*							\
175 		 * Hardware calculates pseudo-header, header and the	\
176 		 * payload checksums, so clear the checksum field in	\
177 		 * the protocol header.					\
178 		 */							\
179 		*(up) = 0;						\
180 		DB_CKSUMFLAGS(mp) |= HCK_FULLCKSUM;			\
181 	} else if ((hck_flags) & HCKSUM_INET_PARTIAL)  {		\
182 		/*							\
183 		 * Partial checksum offload has been enabled.  Fill	\
184 		 * the checksum field in the protocl header with the	\
185 		 * pseudo-header checksum value.			\
186 		 */							\
187 		_sum = ((proto) == IPPROTO_UDP) ?			\
188 		    IP_UDP_CSUM_COMP : IP_TCP_CSUM_COMP;		\
189 		_sum += *(up) + (pseudo);				\
190 		_sum = (_sum & 0xFFFF) + (_sum >> 16);			\
191 		*(up) = (_sum & 0xFFFF) + (_sum >> 16);			\
192 		/*							\
193 		 * Offsets are relative to beginning of IP header.	\
194 		 */							\
195 		DB_CKSUMSTART(mp) = (start);				\
196 		DB_CKSUMSTUFF(mp) = ((proto) == IPPROTO_UDP) ?		\
197 		    (start) + UDP_CHECKSUM_OFFSET :			\
198 		    (start) + TCP_CHECKSUM_OFFSET;			\
199 		DB_CKSUMEND(mp) = (end);				\
200 		DB_CKSUMFLAGS(mp) |= HCK_PARTIALCKSUM;			\
201 	} else {							\
202 		/*							\
203 		 * Software checksumming.				\
204 		 */							\
205 		_sum = ((proto) == IPPROTO_UDP) ?			\
206 		    IP_UDP_CSUM_COMP : IP_TCP_CSUM_COMP;		\
207 		_sum += (pseudo);					\
208 		_sum = IP_CSUM(mp, start, _sum);			\
209 		*(up) = (uint16_t)(((proto) == IPPROTO_UDP) ?		\
210 		    (_sum ? _sum : ~_sum) : _sum);			\
211 	}								\
212 	/*								\
213 	 * Hardware supports IP header checksum offload; clear the	\
214 	 * contents of IP header checksum field as expected by NIC.	\
215 	 * Do this only if we offloaded either full or partial sum.	\
216 	 */								\
217 	if ((ipver) == IPV4_VERSION && DB_CKSUMFLAGS(mp) != 0 &&	\
218 	    ((hck_flags) & HCKSUM_IPHDRCKSUM)) {			\
219 		DB_CKSUMFLAGS(mp) |= HCK_IPV4_HDRCKSUM;			\
220 		((ipha_t *)(ihp))->ipha_hdr_checksum = 0;		\
221 	}								\
222 }
223 
224 /*
225  * Macro to inspect the checksum of a fully-reassembled incoming datagram.
226  */
227 #define	IP_CKSUM_RECV_REASS(hck_flags, off, pseudo, sum, err) {		\
228 	(err) = B_FALSE;						\
229 	if ((hck_flags) & HCK_FULLCKSUM) {				\
230 		/*							\
231 		 * The sum of all fragment checksums should		\
232 		 * result in -0 (0xFFFF) or otherwise invalid.		\
233 		 */							\
234 		if ((sum) != 0xFFFF)					\
235 			(err) = B_TRUE;					\
236 	} else if ((hck_flags) & HCK_PARTIALCKSUM) {			\
237 		(sum) += (pseudo);					\
238 		(sum) = ((sum) & 0xFFFF) + ((sum) >> 16);		\
239 		(sum) = ((sum) & 0xFFFF) + ((sum) >> 16);		\
240 		if (~(sum) & 0xFFFF)					\
241 			(err) = B_TRUE;					\
242 	} else if (((sum) = IP_CSUM(mp, off, pseudo)) != 0) {		\
243 		(err) = B_TRUE;						\
244 	}								\
245 }
246 
247 /*
248  * This macro inspects an incoming packet to see if the checksum value
249  * contained in it is valid; if the hardware has provided the information,
250  * the value is verified, otherwise it performs software checksumming.
251  * The checksum value is returned to caller.
252  */
253 #define	IP_CKSUM_RECV(hck_flags, sum, cksum_start, ulph_off, mp, mp1, err) { \
254 	int32_t _len;							\
255 									\
256 	(err) = B_FALSE;						\
257 	if ((hck_flags) & HCK_FULLCKSUM) {				\
258 		/*							\
259 		 * Full checksum has been computed by the hardware	\
260 		 * and has been attached.  If the driver wants us to	\
261 		 * verify the correctness of the attached value, in	\
262 		 * order to protect against faulty hardware, compare	\
263 		 * it against -0 (0xFFFF) to see if it's valid.		\
264 		 */							\
265 		(sum) = DB_CKSUM16(mp);					\
266 		if (!((hck_flags) & HCK_FULLCKSUM_OK) && (sum) != 0xFFFF) \
267 			(err) = B_TRUE;					\
268 	} else if (((hck_flags) & HCK_PARTIALCKSUM) &&			\
269 	    ((mp1) == NULL || (mp1)->b_cont == NULL) &&			\
270 	    (ulph_off) >= DB_CKSUMSTART(mp) &&				\
271 	    ((_len = (ulph_off) - DB_CKSUMSTART(mp)) & 1) == 0) {	\
272 		uint32_t _adj;						\
273 		/*							\
274 		 * Partial checksum has been calculated by hardware	\
275 		 * and attached to the packet; in addition, any		\
276 		 * prepended extraneous data is even byte aligned,	\
277 		 * and there are at most two mblks associated with	\
278 		 * the packet.  If any such data exists, we adjust	\
279 		 * the checksum; also take care any postpended data.	\
280 		 */							\
281 		IP_ADJCKSUM_PARTIAL(cksum_start, mp, mp1, _len, _adj);	\
282 		/*							\
283 		 * One's complement subtract extraneous checksum	\
284 		 */							\
285 		(sum) += DB_CKSUM16(mp);				\
286 		if (_adj >= (sum))					\
287 			(sum) = ~(_adj - (sum)) & 0xFFFF;		\
288 		else							\
289 			(sum) -= _adj;					\
290 		(sum) = ((sum) & 0xFFFF) + ((int)(sum) >> 16);		\
291 		(sum) = ((sum) & 0xFFFF) + ((int)(sum) >> 16);		\
292 		if (~(sum) & 0xFFFF)					\
293 			(err) = B_TRUE;					\
294 	} else if (((sum) = IP_CSUM(mp, ulph_off, sum)) != 0) {		\
295 		(err) = B_TRUE;						\
296 	}								\
297 }
298 
299 /*
300  * Macro to adjust a given checksum value depending on any prepended
301  * or postpended data on the packet.  It expects the start offset to
302  * begin at an even boundary and that the packet consists of at most
303  * two mblks.
304  */
305 #define	IP_ADJCKSUM_PARTIAL(cksum_start, mp, mp1, len, adj) {		\
306 	/*								\
307 	 * Prepended extraneous data; adjust checksum.			\
308 	 */								\
309 	if ((len) > 0)							\
310 		(adj) = IP_BCSUM_PARTIAL(cksum_start, len, 0);		\
311 	else								\
312 		(adj) = 0;						\
313 	/*								\
314 	 * len is now the total length of mblk(s)			\
315 	 */								\
316 	(len) = MBLKL(mp);						\
317 	if ((mp1) == NULL)						\
318 		(mp1) = (mp);						\
319 	else								\
320 		(len) += MBLKL(mp1);					\
321 	/*								\
322 	 * Postpended extraneous data; adjust checksum.			\
323 	 */								\
324 	if (((len) = (DB_CKSUMEND(mp) - len)) > 0) {			\
325 		uint32_t _pad;						\
326 									\
327 		_pad = IP_BCSUM_PARTIAL((mp1)->b_wptr, len, 0);		\
328 		/*							\
329 		 * If the postpended extraneous data was odd		\
330 		 * byte aligned, swap resulting checksum bytes.		\
331 		 */							\
332 		if ((uintptr_t)(mp1)->b_wptr & 1)			\
333 			(adj) += ((_pad << 8) & 0xFFFF) | (_pad >> 8);	\
334 		else							\
335 			(adj) += _pad;					\
336 		(adj) = ((adj) & 0xFFFF) + ((int)(adj) >> 16);		\
337 	}								\
338 }
339 
340 #define	ILL_MDT_CAPABLE(ill)		\
341 	(((ill)->ill_capabilities & ILL_CAPAB_MDT) != 0)
342 
343 /*
344  * ioctl identifier and structure for Multidata Transmit update
345  * private M_CTL communication from IP to ULP.
346  */
347 #define	MDT_IOC_INFO_UPDATE	(('M' << 8) + 1020)
348 
349 typedef struct ip_mdt_info_s {
350 	uint_t	mdt_info_id;	/* MDT_IOC_INFO_UPDATE */
351 	ill_mdt_capab_t	mdt_capab; /* ILL MDT capabilities */
352 } ip_mdt_info_t;
353 
354 /*
355  * Macro that determines whether or not a given ILL is allowed for MDT.
356  */
357 #define	ILL_MDT_USABLE(ill)						\
358 	(ILL_MDT_CAPABLE(ill) &&					\
359 	ill->ill_mdt_capab != NULL &&					\
360 	ill->ill_mdt_capab->ill_mdt_version == MDT_VERSION_2 &&		\
361 	ill->ill_mdt_capab->ill_mdt_on != 0)
362 
363 #define	ILL_LSO_CAPABLE(ill)		\
364 	(((ill)->ill_capabilities & ILL_CAPAB_LSO) != 0)
365 
366 /*
367  * ioctl identifier and structure for Large Segment Offload
368  * private M_CTL communication from IP to ULP.
369  */
370 #define	LSO_IOC_INFO_UPDATE	(('L' << 24) + ('S' << 16) + ('O' << 8))
371 
372 typedef struct ip_lso_info_s {
373 	uint_t	lso_info_id;	/* LSO_IOC_INFO_UPDATE */
374 	ill_lso_capab_t	lso_capab; /* ILL LSO capabilities */
375 } ip_lso_info_t;
376 
377 /*
378  * Macro that determines whether or not a given ILL is allowed for LSO.
379  */
380 #define	ILL_LSO_USABLE(ill)						\
381 	(ILL_LSO_CAPABLE(ill) &&					\
382 	ill->ill_lso_capab != NULL &&					\
383 	ill->ill_lso_capab->ill_lso_version == LSO_VERSION_1 &&		\
384 	ill->ill_lso_capab->ill_lso_on != 0)
385 
386 #define	ILL_LSO_TCP_USABLE(ill)						\
387 	(ILL_LSO_USABLE(ill) &&						\
388 	ill->ill_lso_capab->ill_lso_flags & LSO_TX_BASIC_TCP_IPV4)
389 
390 /*
391  * Macro that determines whether or not a given CONN may be considered
392  * for fast path prior to proceeding further with LSO or Multidata.
393  */
394 #define	CONN_IS_LSO_MD_FASTPATH(connp)	\
395 	((connp)->conn_dontroute == 0 &&	/* SO_DONTROUTE */	\
396 	!((connp)->conn_nexthop_set) &&		/* IP_NEXTHOP */	\
397 	(connp)->conn_nofailover_ill == NULL &&	/* IPIF_NOFAILOVER */	\
398 	(connp)->conn_outgoing_pill == NULL &&	/* IP{V6}_BOUND_PIF */	\
399 	(connp)->conn_outgoing_ill == NULL)	/* IP{V6}_BOUND_IF */
400 
401 /* Definitons for fragmenting IP packets using MDT. */
402 
403 /*
404  * Smaller and private version of pdescinfo_t used specifically for IP,
405  * which allows for only a single payload span per packet.
406  */
407 typedef struct ip_pdescinfo_s PDESCINFO_STRUCT(2)	ip_pdescinfo_t;
408 
409 /*
410  * Macro version of ip_can_frag_mdt() which avoids the function call if we
411  * only examine a single message block.
412  */
413 #define	IP_CAN_FRAG_MDT(mp, hdr_len, len)			\
414 	(((mp)->b_cont == NULL) ?				\
415 	(MBLKL(mp) >= ((hdr_len) + ip_wput_frag_mdt_min)) :	\
416 	ip_can_frag_mdt((mp), (hdr_len), (len)))
417 
418 /*
419  * Macro that determines whether or not a given IPC requires
420  * outbound IPSEC processing.
421  */
422 #define	CONN_IPSEC_OUT_ENCAPSULATED(connp)	\
423 	((connp)->conn_out_enforce_policy ||	\
424 	((connp)->conn_latch != NULL &&		\
425 	(connp)->conn_latch->ipl_out_policy != NULL))
426 
427 /*
428  * These are used by the synchronous streams code in tcp and udp.
429  * When we set the flags for a wakeup from a synchronous stream we
430  * always set RSLEEP in sd_wakeq, even if we have a read thread waiting
431  * to do the io. This is in case the read thread gets interrupted
432  * before completing the io. The RSLEEP flag in sd_wakeq is used to
433  * indicate that there is data available at the synchronous barrier.
434  * The assumption is that subsequent functions calls through rwnext()
435  * will reset sd_wakeq appropriately.
436  */
437 #define	STR_WAKEUP_CLEAR(stp) {						\
438 	mutex_enter(&stp->sd_lock);					\
439 	stp->sd_wakeq &= ~RSLEEP;					\
440 	mutex_exit(&stp->sd_lock);					\
441 }
442 
443 #define	STR_WAKEUP_SET(stp) {						\
444 	mutex_enter(&stp->sd_lock);					\
445 	if (stp->sd_flag & RSLEEP) {					\
446 		stp->sd_flag &= ~RSLEEP;				\
447 		cv_broadcast(&_RD(stp->sd_wrq)->q_wait);		\
448 	}								\
449 	stp->sd_wakeq |= RSLEEP;					\
450 	mutex_exit(&stp->sd_lock);					\
451 }
452 
453 /*
454  * Combined wakeup and sendsig to avoid dropping and reacquiring the
455  * sd_lock. The list of messages waiting at the synchronous barrier is
456  * supplied in order to determine whether a wakeup needs to occur. We
457  * only send a wakeup to the application when necessary, i.e. during
458  * the first enqueue when the received messages list will be NULL.
459  */
460 #define	STR_WAKEUP_SENDSIG(stp, rcv_list) {				\
461 	int _events;							\
462 	mutex_enter(&stp->sd_lock);					\
463 	if (rcv_list == NULL) {						\
464 		if (stp->sd_flag & RSLEEP) {				\
465 			stp->sd_flag &= ~RSLEEP;			\
466 			cv_broadcast(&_RD(stp->sd_wrq)->q_wait);	\
467 		}							\
468 		stp->sd_wakeq |= RSLEEP;				\
469 	}								\
470 	if ((_events = stp->sd_sigflags & (S_INPUT | S_RDNORM)) != 0)	\
471 		strsendsig(stp->sd_siglist, _events, 0, 0);		\
472 	if (stp->sd_rput_opt & SR_POLLIN) {				\
473 		stp->sd_rput_opt &= ~SR_POLLIN;				\
474 		mutex_exit(&stp->sd_lock);				\
475 		pollwakeup(&stp->sd_pollist, POLLIN | POLLRDNORM);	\
476 	} else {							\
477 		mutex_exit(&stp->sd_lock);				\
478 	}								\
479 }
480 
481 #define	CONN_UDP_SYNCSTR(connp)						\
482 	(IPCL_IS_UDP(connp) && (connp)->conn_udp->udp_direct_sockfs)
483 
484 /*
485  * Macro that checks whether or not a particular UDP conn is
486  * flow-controlling on the read-side.  If udp module is directly
487  * above ip, check to see if the drain queue is full; note here
488  * that we check this without any lock protection because this
489  * is a coarse granularity inbound flow-control.  If the module
490  * above ip is not udp, then use canputnext to determine the
491  * flow-control.
492  *
493  * Note that these checks are done after the conn is found in
494  * the UDP fanout table.
495  * FIXME? Might be faster to check both udp_drain_qfull and canputnext.
496  */
497 #define	CONN_UDP_FLOWCTLD(connp)					\
498 	(CONN_UDP_SYNCSTR(connp) ?					\
499 	(connp)->conn_udp->udp_drain_qfull :				\
500 	!canputnext((connp)->conn_rq))
501 
502 #define	ILL_DLS_CAPABLE(ill)	\
503 	(((ill)->ill_capabilities &		\
504 	(ILL_CAPAB_POLL|ILL_CAPAB_SOFT_RING)) != 0)
505 
506 /*
507  * Macro that hands off one or more messages directly to DLD
508  * when the interface is marked with ILL_CAPAB_POLL.
509  */
510 #define	IP_DLS_ILL_TX(ill, ipha, mp, ipst) {				\
511 	ill_dls_capab_t *ill_dls = ill->ill_dls_capab;			\
512 	ASSERT(ILL_DLS_CAPABLE(ill));					\
513 	ASSERT(ill_dls != NULL);					\
514 	ASSERT(ill_dls->ill_tx != NULL);				\
515 	ASSERT(ill_dls->ill_tx_handle != NULL);				\
516 	DTRACE_PROBE4(ip4__physical__out__start,			\
517 	    ill_t *, NULL, ill_t *, ill,				\
518 	    ipha_t *, ipha, mblk_t *, mp);				\
519 	FW_HOOKS(ipst->ips_ip4_physical_out_event,			\
520 	    ipst->ips_ipv4firewall_physical_out,			\
521 	    NULL, ill, ipha, mp, mp, 0, ipst);				\
522 	DTRACE_PROBE1(ip4__physical__out__end, mblk_t *, mp);		\
523 	if (mp != NULL)	{						\
524 		DTRACE_IP7(send, mblk_t *, mp, conn_t *, NULL,		\
525 		    void_ip_t *, ipha, __dtrace_ipsr_ill_t *, ill,	\
526 		    ipha_t *, ipha, ip6_t *, NULL, int,	0);		\
527 		ill_dls->ill_tx(ill_dls->ill_tx_handle, mp);		\
528 	}								\
529 }
530 
531 extern int	ip_wput_frag_mdt_min;
532 extern boolean_t ip_can_frag_mdt(mblk_t *, ssize_t, ssize_t);
533 extern mblk_t   *ip_prepend_zoneid(mblk_t *, zoneid_t, ip_stack_t *);
534 
535 #endif	/* _KERNEL */
536 
537 #ifdef	__cplusplus
538 }
539 #endif
540 
541 #endif	/* _INET_IP_IMPL_H */
542