xref: /freebsd/sys/netinet/tcp_lro.c (revision 66df505066f51e6d8411b966765d828817f88971)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2007, Myricom Inc.
5  * Copyright (c) 2008, Intel Corporation.
6  * Copyright (c) 2012 The FreeBSD Foundation
7  * Copyright (c) 2016-2021 Mellanox Technologies.
8  * All rights reserved.
9  *
10  * Portions of this software were developed by Bjoern Zeeb
11  * under sponsorship from the FreeBSD Foundation.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/socket.h>
47 #include <sys/socketvar.h>
48 #include <sys/sockbuf.h>
49 #include <sys/sysctl.h>
50 
51 #include <net/if.h>
52 #include <net/if_var.h>
53 #include <net/ethernet.h>
54 #include <net/bpf.h>
55 #include <net/vnet.h>
56 
57 #include <netinet/in_systm.h>
58 #include <netinet/in.h>
59 #include <netinet/ip6.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/in_pcb.h>
63 #include <netinet6/in6_pcb.h>
64 #include <netinet/tcp.h>
65 #include <netinet/tcp_seq.h>
66 #include <netinet/tcp_lro.h>
67 #include <netinet/tcp_var.h>
68 #include <netinet/tcpip.h>
69 #include <netinet/tcp_hpts.h>
70 #include <netinet/tcp_log_buf.h>
71 #include <netinet/udp.h>
72 #include <netinet6/ip6_var.h>
73 
74 #include <machine/in_cksum.h>
75 
76 static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures");
77 
78 #define	TCP_LRO_TS_OPTION \
79     ntohl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | \
80 	  (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)
81 
82 static void	tcp_lro_rx_done(struct lro_ctrl *lc);
83 static int	tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m,
84 		    uint32_t csum, bool use_hash);
85 
86 #ifdef TCPHPTS
87 static bool	do_bpf_strip_and_compress(struct inpcb *, struct lro_ctrl *,
88 		struct lro_entry *, struct mbuf **, struct mbuf **, struct mbuf **, bool *, bool);
89 
90 #endif
91 
92 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, lro,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
93     "TCP LRO");
94 
95 static long tcplro_stacks_wanting_mbufq;
96 counter_u64_t tcp_inp_lro_direct_queue;
97 counter_u64_t tcp_inp_lro_wokeup_queue;
98 counter_u64_t tcp_inp_lro_compressed;
99 counter_u64_t tcp_inp_lro_locks_taken;
100 counter_u64_t tcp_extra_mbuf;
101 counter_u64_t tcp_would_have_but;
102 counter_u64_t tcp_comp_total;
103 counter_u64_t tcp_uncomp_total;
104 counter_u64_t tcp_bad_csums;
105 
106 static unsigned	tcp_lro_entries = TCP_LRO_ENTRIES;
107 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries,
108     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0,
109     "default number of LRO entries");
110 
111 static uint32_t tcp_lro_cpu_set_thresh = TCP_LRO_CPU_DECLARATION_THRESH;
112 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, lro_cpu_threshold,
113     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_cpu_set_thresh, 0,
114     "Number of interrups in a row on the same CPU that will make us declare an 'affinity' cpu?");
115 
116 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, fullqueue, CTLFLAG_RD,
117     &tcp_inp_lro_direct_queue, "Number of lro's fully queued to transport");
118 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, wokeup, CTLFLAG_RD,
119     &tcp_inp_lro_wokeup_queue, "Number of lro's where we woke up transport via hpts");
120 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, compressed, CTLFLAG_RD,
121     &tcp_inp_lro_compressed, "Number of lro's compressed and sent to transport");
122 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lockcnt, CTLFLAG_RD,
123     &tcp_inp_lro_locks_taken, "Number of lro's inp_wlocks taken");
124 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, extra_mbuf, CTLFLAG_RD,
125     &tcp_extra_mbuf, "Number of times we had an extra compressed ack dropped into the tp");
126 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, would_have_but, CTLFLAG_RD,
127     &tcp_would_have_but, "Number of times we would have had an extra compressed, but mget failed");
128 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, with_m_ackcmp, CTLFLAG_RD,
129     &tcp_comp_total, "Number of mbufs queued with M_ACKCMP flags set");
130 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, without_m_ackcmp, CTLFLAG_RD,
131     &tcp_uncomp_total, "Number of mbufs queued without M_ACKCMP");
132 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lro_badcsum, CTLFLAG_RD,
133     &tcp_bad_csums, "Number of packets that the common code saw with bad csums");
134 
135 void
136 tcp_lro_reg_mbufq(void)
137 {
138 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, 1);
139 }
140 
141 void
142 tcp_lro_dereg_mbufq(void)
143 {
144 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, -1);
145 }
146 
147 static __inline void
148 tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_head *bucket,
149     struct lro_entry *le)
150 {
151 
152 	LIST_INSERT_HEAD(&lc->lro_active, le, next);
153 	LIST_INSERT_HEAD(bucket, le, hash_next);
154 }
155 
156 static __inline void
157 tcp_lro_active_remove(struct lro_entry *le)
158 {
159 
160 	LIST_REMOVE(le, next);		/* active list */
161 	LIST_REMOVE(le, hash_next);	/* hash bucket */
162 }
163 
164 int
165 tcp_lro_init(struct lro_ctrl *lc)
166 {
167 	return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0));
168 }
169 
170 int
171 tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
172     unsigned lro_entries, unsigned lro_mbufs)
173 {
174 	struct lro_entry *le;
175 	size_t size;
176 	unsigned i, elements;
177 
178 	lc->lro_bad_csum = 0;
179 	lc->lro_queued = 0;
180 	lc->lro_flushed = 0;
181 	lc->lro_mbuf_count = 0;
182 	lc->lro_mbuf_max = lro_mbufs;
183 	lc->lro_cnt = lro_entries;
184 	lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
185 	lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
186 	lc->ifp = ifp;
187 	LIST_INIT(&lc->lro_free);
188 	LIST_INIT(&lc->lro_active);
189 
190 	/* create hash table to accelerate entry lookup */
191 	if (lro_entries > lro_mbufs)
192 		elements = lro_entries;
193 	else
194 		elements = lro_mbufs;
195 	lc->lro_hash = phashinit_flags(elements, M_LRO, &lc->lro_hashsz,
196 	    HASH_NOWAIT);
197 	if (lc->lro_hash == NULL) {
198 		memset(lc, 0, sizeof(*lc));
199 		return (ENOMEM);
200 	}
201 
202 	/* compute size to allocate */
203 	size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
204 	    (lro_entries * sizeof(*le));
205 	lc->lro_mbuf_data = (struct lro_mbuf_sort *)
206 	    malloc(size, M_LRO, M_NOWAIT | M_ZERO);
207 
208 	/* check for out of memory */
209 	if (lc->lro_mbuf_data == NULL) {
210 		free(lc->lro_hash, M_LRO);
211 		memset(lc, 0, sizeof(*lc));
212 		return (ENOMEM);
213 	}
214 	/* compute offset for LRO entries */
215 	le = (struct lro_entry *)
216 	    (lc->lro_mbuf_data + lro_mbufs);
217 
218 	/* setup linked list */
219 	for (i = 0; i != lro_entries; i++)
220 		LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
221 
222 	return (0);
223 }
224 
225 struct vxlan_header {
226 	uint32_t	vxlh_flags;
227 	uint32_t	vxlh_vni;
228 };
229 
230 static inline void *
231 tcp_lro_low_level_parser(void *ptr, struct lro_parser *parser, bool update_data, bool is_vxlan, int mlen)
232 {
233 	const struct ether_vlan_header *eh;
234 	void *old;
235 	uint16_t eth_type;
236 
237 	if (update_data)
238 		memset(parser, 0, sizeof(*parser));
239 
240 	old = ptr;
241 
242 	if (is_vxlan) {
243 		const struct vxlan_header *vxh;
244 		vxh = ptr;
245 		ptr = (uint8_t *)ptr + sizeof(*vxh);
246 		if (update_data) {
247 			parser->data.vxlan_vni =
248 			    vxh->vxlh_vni & htonl(0xffffff00);
249 		}
250 	}
251 
252 	eh = ptr;
253 	if (__predict_false(eh->evl_encap_proto == htons(ETHERTYPE_VLAN))) {
254 		eth_type = eh->evl_proto;
255 		if (update_data) {
256 			/* strip priority and keep VLAN ID only */
257 			parser->data.vlan_id = eh->evl_tag & htons(EVL_VLID_MASK);
258 		}
259 		/* advance to next header */
260 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
261 		mlen -= (ETHER_HDR_LEN  + ETHER_VLAN_ENCAP_LEN);
262 	} else {
263 		eth_type = eh->evl_encap_proto;
264 		/* advance to next header */
265 		mlen -= ETHER_HDR_LEN;
266 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN;
267 	}
268 	if (__predict_false(mlen <= 0))
269 		return (NULL);
270 	switch (eth_type) {
271 #ifdef INET
272 	case htons(ETHERTYPE_IP):
273 		parser->ip4 = ptr;
274 		if (__predict_false(mlen < sizeof(struct ip)))
275 			return (NULL);
276 		/* Ensure there are no IPv4 options. */
277 		if ((parser->ip4->ip_hl << 2) != sizeof (*parser->ip4))
278 			break;
279 		/* .. and the packet is not fragmented. */
280 		if (parser->ip4->ip_off & htons(IP_MF|IP_OFFMASK))
281 			break;
282 		ptr = (uint8_t *)ptr + (parser->ip4->ip_hl << 2);
283 		mlen -= sizeof(struct ip);
284 		if (update_data) {
285 			parser->data.s_addr.v4 = parser->ip4->ip_src;
286 			parser->data.d_addr.v4 = parser->ip4->ip_dst;
287 		}
288 		switch (parser->ip4->ip_p) {
289 		case IPPROTO_UDP:
290 			if (__predict_false(mlen < sizeof(struct udphdr)))
291 				return (NULL);
292 			parser->udp = ptr;
293 			if (update_data) {
294 				parser->data.lro_type = LRO_TYPE_IPV4_UDP;
295 				parser->data.s_port = parser->udp->uh_sport;
296 				parser->data.d_port = parser->udp->uh_dport;
297 			} else {
298 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_UDP);
299 			}
300 			ptr = ((uint8_t *)ptr + sizeof(*parser->udp));
301 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
302 			return (ptr);
303 		case IPPROTO_TCP:
304 			parser->tcp = ptr;
305 			if (__predict_false(mlen < sizeof(struct tcphdr)))
306 				return (NULL);
307 			if (update_data) {
308 				parser->data.lro_type = LRO_TYPE_IPV4_TCP;
309 				parser->data.s_port = parser->tcp->th_sport;
310 				parser->data.d_port = parser->tcp->th_dport;
311 			} else {
312 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_TCP);
313 			}
314 			if (__predict_false(mlen < (parser->tcp->th_off << 2)))
315 				return (NULL);
316 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
317 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
318 			return (ptr);
319 		default:
320 			break;
321 		}
322 		break;
323 #endif
324 #ifdef INET6
325 	case htons(ETHERTYPE_IPV6):
326 		parser->ip6 = ptr;
327 		if (__predict_false(mlen < sizeof(struct ip6_hdr)))
328 			return (NULL);
329 		ptr = (uint8_t *)ptr + sizeof(*parser->ip6);
330 		if (update_data) {
331 			parser->data.s_addr.v6 = parser->ip6->ip6_src;
332 			parser->data.d_addr.v6 = parser->ip6->ip6_dst;
333 		}
334 		mlen -= sizeof(struct ip6_hdr);
335 		switch (parser->ip6->ip6_nxt) {
336 		case IPPROTO_UDP:
337 			if (__predict_false(mlen < sizeof(struct udphdr)))
338 				return (NULL);
339 			parser->udp = ptr;
340 			if (update_data) {
341 				parser->data.lro_type = LRO_TYPE_IPV6_UDP;
342 				parser->data.s_port = parser->udp->uh_sport;
343 				parser->data.d_port = parser->udp->uh_dport;
344 			} else {
345 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_UDP);
346 			}
347 			ptr = (uint8_t *)ptr + sizeof(*parser->udp);
348 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
349 			return (ptr);
350 		case IPPROTO_TCP:
351 			if (__predict_false(mlen < sizeof(struct tcphdr)))
352 				return (NULL);
353 			parser->tcp = ptr;
354 			if (update_data) {
355 				parser->data.lro_type = LRO_TYPE_IPV6_TCP;
356 				parser->data.s_port = parser->tcp->th_sport;
357 				parser->data.d_port = parser->tcp->th_dport;
358 			} else {
359 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_TCP);
360 			}
361 			if (__predict_false(mlen < (parser->tcp->th_off << 2)))
362 				return (NULL);
363 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
364 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
365 			return (ptr);
366 		default:
367 			break;
368 		}
369 		break;
370 #endif
371 	default:
372 		break;
373 	}
374 	/* Invalid packet - cannot parse */
375 	return (NULL);
376 }
377 
378 static const int vxlan_csum = CSUM_INNER_L3_CALC | CSUM_INNER_L3_VALID |
379     CSUM_INNER_L4_CALC | CSUM_INNER_L4_VALID;
380 
381 static inline struct lro_parser *
382 tcp_lro_parser(struct mbuf *m, struct lro_parser *po, struct lro_parser *pi, bool update_data)
383 {
384 	void *data_ptr;
385 
386 	/* Try to parse outer headers first. */
387 	data_ptr = tcp_lro_low_level_parser(m->m_data, po, update_data, false, m->m_len);
388 	if (data_ptr == NULL || po->total_hdr_len > m->m_len)
389 		return (NULL);
390 
391 	if (update_data) {
392 		/* Store VLAN ID, if any. */
393 		if (__predict_false(m->m_flags & M_VLANTAG)) {
394 			po->data.vlan_id =
395 			    htons(m->m_pkthdr.ether_vtag) & htons(EVL_VLID_MASK);
396 		}
397 		/* Store decrypted flag, if any. */
398 		if (__predict_false((m->m_pkthdr.csum_flags &
399 		    CSUM_TLS_MASK) == CSUM_TLS_DECRYPTED))
400 			po->data.lro_flags |= LRO_FLAG_DECRYPTED;
401 	}
402 
403 	switch (po->data.lro_type) {
404 	case LRO_TYPE_IPV4_UDP:
405 	case LRO_TYPE_IPV6_UDP:
406 		/* Check for VXLAN headers. */
407 		if ((m->m_pkthdr.csum_flags & vxlan_csum) != vxlan_csum)
408 			break;
409 
410 		/* Try to parse inner headers. */
411 		data_ptr = tcp_lro_low_level_parser(data_ptr, pi, update_data, true,
412 						    (m->m_len - ((caddr_t)data_ptr - m->m_data)));
413 		if (data_ptr == NULL || (pi->total_hdr_len + po->total_hdr_len) > m->m_len)
414 			break;
415 
416 		/* Verify supported header types. */
417 		switch (pi->data.lro_type) {
418 		case LRO_TYPE_IPV4_TCP:
419 		case LRO_TYPE_IPV6_TCP:
420 			return (pi);
421 		default:
422 			break;
423 		}
424 		break;
425 	case LRO_TYPE_IPV4_TCP:
426 	case LRO_TYPE_IPV6_TCP:
427 		if (update_data)
428 			memset(pi, 0, sizeof(*pi));
429 		return (po);
430 	default:
431 		break;
432 	}
433 	return (NULL);
434 }
435 
436 static inline int
437 tcp_lro_trim_mbuf_chain(struct mbuf *m, const struct lro_parser *po)
438 {
439 	int len;
440 
441 	switch (po->data.lro_type) {
442 #ifdef INET
443 	case LRO_TYPE_IPV4_TCP:
444 		len = ((uint8_t *)po->ip4 - (uint8_t *)m->m_data) +
445 		    ntohs(po->ip4->ip_len);
446 		break;
447 #endif
448 #ifdef INET6
449 	case LRO_TYPE_IPV6_TCP:
450 		len = ((uint8_t *)po->ip6 - (uint8_t *)m->m_data) +
451 		    ntohs(po->ip6->ip6_plen) + sizeof(*po->ip6);
452 		break;
453 #endif
454 	default:
455 		return (TCP_LRO_CANNOT);
456 	}
457 
458 	/*
459 	 * If the frame is padded beyond the end of the IP packet,
460 	 * then trim the extra bytes off:
461 	 */
462 	if (__predict_true(m->m_pkthdr.len == len)) {
463 		return (0);
464 	} else if (m->m_pkthdr.len > len) {
465 		m_adj(m, len - m->m_pkthdr.len);
466 		return (0);
467 	}
468 	return (TCP_LRO_CANNOT);
469 }
470 
471 static struct tcphdr *
472 tcp_lro_get_th(struct mbuf *m)
473 {
474 	return ((struct tcphdr *)((uint8_t *)m->m_data + m->m_pkthdr.lro_tcp_h_off));
475 }
476 
477 static void
478 lro_free_mbuf_chain(struct mbuf *m)
479 {
480 	struct mbuf *save;
481 
482 	while (m) {
483 		save = m->m_nextpkt;
484 		m->m_nextpkt = NULL;
485 		m_freem(m);
486 		m = save;
487 	}
488 }
489 
490 void
491 tcp_lro_free(struct lro_ctrl *lc)
492 {
493 	struct lro_entry *le;
494 	unsigned x;
495 
496 	/* reset LRO free list */
497 	LIST_INIT(&lc->lro_free);
498 
499 	/* free active mbufs, if any */
500 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
501 		tcp_lro_active_remove(le);
502 		lro_free_mbuf_chain(le->m_head);
503 	}
504 
505 	/* free hash table */
506 	free(lc->lro_hash, M_LRO);
507 	lc->lro_hash = NULL;
508 	lc->lro_hashsz = 0;
509 
510 	/* free mbuf array, if any */
511 	for (x = 0; x != lc->lro_mbuf_count; x++)
512 		m_freem(lc->lro_mbuf_data[x].mb);
513 	lc->lro_mbuf_count = 0;
514 
515 	/* free allocated memory, if any */
516 	free(lc->lro_mbuf_data, M_LRO);
517 	lc->lro_mbuf_data = NULL;
518 }
519 
520 static uint16_t
521 tcp_lro_rx_csum_tcphdr(const struct tcphdr *th)
522 {
523 	const uint16_t *ptr;
524 	uint32_t csum;
525 	uint16_t len;
526 
527 	csum = -th->th_sum;	/* exclude checksum field */
528 	len = th->th_off;
529 	ptr = (const uint16_t *)th;
530 	while (len--) {
531 		csum += *ptr;
532 		ptr++;
533 		csum += *ptr;
534 		ptr++;
535 	}
536 	while (csum > 0xffff)
537 		csum = (csum >> 16) + (csum & 0xffff);
538 
539 	return (csum);
540 }
541 
542 static uint16_t
543 tcp_lro_rx_csum_data(const struct lro_parser *pa, uint16_t tcp_csum)
544 {
545 	uint32_t c;
546 	uint16_t cs;
547 
548 	c = tcp_csum;
549 
550 	switch (pa->data.lro_type) {
551 #ifdef INET6
552 	case LRO_TYPE_IPV6_TCP:
553 		/* Compute full pseudo IPv6 header checksum. */
554 		cs = in6_cksum_pseudo(pa->ip6, ntohs(pa->ip6->ip6_plen), pa->ip6->ip6_nxt, 0);
555 		break;
556 #endif
557 #ifdef INET
558 	case LRO_TYPE_IPV4_TCP:
559 		/* Compute full pseudo IPv4 header checsum. */
560 		cs = in_addword(ntohs(pa->ip4->ip_len) - sizeof(*pa->ip4), IPPROTO_TCP);
561 		cs = in_pseudo(pa->ip4->ip_src.s_addr, pa->ip4->ip_dst.s_addr, htons(cs));
562 		break;
563 #endif
564 	default:
565 		cs = 0;		/* Keep compiler happy. */
566 		break;
567 	}
568 
569 	/* Complement checksum. */
570 	cs = ~cs;
571 	c += cs;
572 
573 	/* Remove TCP header checksum. */
574 	cs = ~tcp_lro_rx_csum_tcphdr(pa->tcp);
575 	c += cs;
576 
577 	/* Compute checksum remainder. */
578 	while (c > 0xffff)
579 		c = (c >> 16) + (c & 0xffff);
580 
581 	return (c);
582 }
583 
584 static void
585 tcp_lro_rx_done(struct lro_ctrl *lc)
586 {
587 	struct lro_entry *le;
588 
589 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
590 		tcp_lro_active_remove(le);
591 		tcp_lro_flush(lc, le);
592 	}
593 }
594 
595 void
596 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
597 {
598 	struct lro_entry *le, *le_tmp;
599 	uint64_t now, tov;
600 	struct bintime bt;
601 
602 	NET_EPOCH_ASSERT();
603 	if (LIST_EMPTY(&lc->lro_active))
604 		return;
605 
606 	/* get timeout time and current time in ns */
607 	binuptime(&bt);
608 	now = bintime2ns(&bt);
609 	tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000));
610 	LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
611 		if (now >= (bintime2ns(&le->alloc_time) + tov)) {
612 			tcp_lro_active_remove(le);
613 			tcp_lro_flush(lc, le);
614 		}
615 	}
616 }
617 
618 #ifdef INET
619 static int
620 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4)
621 {
622 	uint16_t csum;
623 
624 	/* Legacy IP has a header checksum that needs to be correct. */
625 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
626 		if (__predict_false((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0)) {
627 			lc->lro_bad_csum++;
628 			return (TCP_LRO_CANNOT);
629 		}
630 	} else {
631 		csum = in_cksum_hdr(ip4);
632 		if (__predict_false(csum != 0)) {
633 			lc->lro_bad_csum++;
634 			return (TCP_LRO_CANNOT);
635 		}
636 	}
637 	return (0);
638 }
639 #endif
640 
641 #ifdef TCPHPTS
642 static void
643 tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
644     const struct lro_entry *le, const struct mbuf *m,
645     int frm, int32_t tcp_data_len, uint32_t th_seq,
646     uint32_t th_ack, uint16_t th_win)
647 {
648 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
649 		union tcp_log_stackspecific log;
650 		struct timeval tv, btv;
651 		uint32_t cts;
652 
653 		cts = tcp_get_usecs(&tv);
654 		memset(&log, 0, sizeof(union tcp_log_stackspecific));
655 		log.u_bbr.flex8 = frm;
656 		log.u_bbr.flex1 = tcp_data_len;
657 		if (m)
658 			log.u_bbr.flex2 = m->m_pkthdr.len;
659 		else
660 			log.u_bbr.flex2 = 0;
661 		log.u_bbr.flex3 = le->m_head->m_pkthdr.lro_nsegs;
662 		log.u_bbr.flex4 = le->m_head->m_pkthdr.lro_tcp_d_len;
663 		if (le->m_head) {
664 			log.u_bbr.flex5 = le->m_head->m_pkthdr.len;
665 			log.u_bbr.delRate = le->m_head->m_flags;
666 			log.u_bbr.rttProp = le->m_head->m_pkthdr.rcv_tstmp;
667 		}
668 		log.u_bbr.inflight = th_seq;
669 		log.u_bbr.delivered = th_ack;
670 		log.u_bbr.timeStamp = cts;
671 		log.u_bbr.epoch = le->next_seq;
672 		log.u_bbr.lt_epoch = le->ack_seq;
673 		log.u_bbr.pacing_gain = th_win;
674 		log.u_bbr.cwnd_gain = le->window;
675 		log.u_bbr.lost = curcpu;
676 		log.u_bbr.cur_del_rate = (uintptr_t)m;
677 		log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
678 		bintime2timeval(&lc->lro_last_queue_time, &btv);
679 		log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
680 		log.u_bbr.flex7 = le->compressed;
681 		log.u_bbr.pacing_gain = le->uncompressed;
682 		if (in_epoch(net_epoch_preempt))
683 			log.u_bbr.inhpts = 1;
684 		else
685 			log.u_bbr.inhpts = 0;
686 		TCP_LOG_EVENTP(tp, NULL,
687 			       &tp->t_inpcb->inp_socket->so_rcv,
688 			       &tp->t_inpcb->inp_socket->so_snd,
689 			       TCP_LOG_LRO, 0,
690 			       0, &log, false, &tv);
691 	}
692 }
693 #endif
694 
695 static inline void
696 tcp_lro_assign_and_checksum_16(uint16_t *ptr, uint16_t value, uint16_t *psum)
697 {
698 	uint32_t csum;
699 
700 	csum = 0xffff - *ptr + value;
701 	while (csum > 0xffff)
702 		csum = (csum >> 16) + (csum & 0xffff);
703 	*ptr = value;
704 	*psum = csum;
705 }
706 
707 static uint16_t
708 tcp_lro_update_checksum(const struct lro_parser *pa, const struct lro_entry *le,
709     uint16_t payload_len, uint16_t delta_sum)
710 {
711 	uint32_t csum;
712 	uint16_t tlen;
713 	uint16_t temp[5] = {};
714 
715 	switch (pa->data.lro_type) {
716 	case LRO_TYPE_IPV4_TCP:
717 		/* Compute new IPv4 length. */
718 		tlen = (pa->ip4->ip_hl << 2) + (pa->tcp->th_off << 2) + payload_len;
719 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
720 
721 		/* Subtract delta from current IPv4 checksum. */
722 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
723 		while (csum > 0xffff)
724 			csum = (csum >> 16) + (csum & 0xffff);
725 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
726 		goto update_tcp_header;
727 
728 	case LRO_TYPE_IPV6_TCP:
729 		/* Compute new IPv6 length. */
730 		tlen = (pa->tcp->th_off << 2) + payload_len;
731 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
732 		goto update_tcp_header;
733 
734 	case LRO_TYPE_IPV4_UDP:
735 		/* Compute new IPv4 length. */
736 		tlen = (pa->ip4->ip_hl << 2) + sizeof(*pa->udp) + payload_len;
737 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
738 
739 		/* Subtract delta from current IPv4 checksum. */
740 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
741 		while (csum > 0xffff)
742 			csum = (csum >> 16) + (csum & 0xffff);
743 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
744 		goto update_udp_header;
745 
746 	case LRO_TYPE_IPV6_UDP:
747 		/* Compute new IPv6 length. */
748 		tlen = sizeof(*pa->udp) + payload_len;
749 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
750 		goto update_udp_header;
751 
752 	default:
753 		return (0);
754 	}
755 
756 update_tcp_header:
757 	/* Compute current TCP header checksum. */
758 	temp[2] = tcp_lro_rx_csum_tcphdr(pa->tcp);
759 
760 	/* Incorporate the latest ACK into the TCP header. */
761 	pa->tcp->th_ack = le->ack_seq;
762 	pa->tcp->th_win = le->window;
763 
764 	/* Incorporate latest timestamp into the TCP header. */
765 	if (le->timestamp != 0) {
766 		uint32_t *ts_ptr;
767 
768 		ts_ptr = (uint32_t *)(pa->tcp + 1);
769 		ts_ptr[1] = htonl(le->tsval);
770 		ts_ptr[2] = le->tsecr;
771 	}
772 
773 	/* Compute new TCP header checksum. */
774 	temp[3] = tcp_lro_rx_csum_tcphdr(pa->tcp);
775 
776 	/* Compute new TCP checksum. */
777 	csum = pa->tcp->th_sum + 0xffff - delta_sum +
778 	    0xffff - temp[0] + 0xffff - temp[3] + temp[2];
779 	while (csum > 0xffff)
780 		csum = (csum >> 16) + (csum & 0xffff);
781 
782 	/* Assign new TCP checksum. */
783 	tcp_lro_assign_and_checksum_16(&pa->tcp->th_sum, csum, &temp[4]);
784 
785 	/* Compute all modififications affecting next checksum. */
786 	csum = temp[0] + temp[1] + 0xffff - temp[2] +
787 	    temp[3] + temp[4] + delta_sum;
788 	while (csum > 0xffff)
789 		csum = (csum >> 16) + (csum & 0xffff);
790 
791 	/* Return delta checksum to next stage, if any. */
792 	return (csum);
793 
794 update_udp_header:
795 	tlen = sizeof(*pa->udp) + payload_len;
796 	/* Assign new UDP length and compute checksum delta. */
797 	tcp_lro_assign_and_checksum_16(&pa->udp->uh_ulen, htons(tlen), &temp[2]);
798 
799 	/* Check if there is a UDP checksum. */
800 	if (__predict_false(pa->udp->uh_sum != 0)) {
801 		/* Compute new UDP checksum. */
802 		csum = pa->udp->uh_sum + 0xffff - delta_sum +
803 		    0xffff - temp[0] + 0xffff - temp[2];
804 		while (csum > 0xffff)
805 			csum = (csum >> 16) + (csum & 0xffff);
806 		/* Assign new UDP checksum. */
807 		tcp_lro_assign_and_checksum_16(&pa->udp->uh_sum, csum, &temp[3]);
808 	}
809 
810 	/* Compute all modififications affecting next checksum. */
811 	csum = temp[0] + temp[1] + temp[2] + temp[3] + delta_sum;
812 	while (csum > 0xffff)
813 		csum = (csum >> 16) + (csum & 0xffff);
814 
815 	/* Return delta checksum to next stage, if any. */
816 	return (csum);
817 }
818 
819 static void
820 tcp_flush_out_entry(struct lro_ctrl *lc, struct lro_entry *le)
821 {
822 	/* Check if we need to recompute any checksums. */
823 	if (le->m_head->m_pkthdr.lro_nsegs > 1) {
824 		uint16_t csum;
825 
826 		switch (le->inner.data.lro_type) {
827 		case LRO_TYPE_IPV4_TCP:
828 			csum = tcp_lro_update_checksum(&le->inner, le,
829 			    le->m_head->m_pkthdr.lro_tcp_d_len,
830 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
831 			csum = tcp_lro_update_checksum(&le->outer, NULL,
832 			    le->m_head->m_pkthdr.lro_tcp_d_len +
833 			    le->inner.total_hdr_len, csum);
834 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
835 			    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
836 			le->m_head->m_pkthdr.csum_data = 0xffff;
837 			if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
838 				le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
839 			break;
840 		case LRO_TYPE_IPV6_TCP:
841 			csum = tcp_lro_update_checksum(&le->inner, le,
842 			    le->m_head->m_pkthdr.lro_tcp_d_len,
843 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
844 			csum = tcp_lro_update_checksum(&le->outer, NULL,
845 			    le->m_head->m_pkthdr.lro_tcp_d_len +
846 			    le->inner.total_hdr_len, csum);
847 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
848 			    CSUM_PSEUDO_HDR;
849 			le->m_head->m_pkthdr.csum_data = 0xffff;
850 			if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
851 				le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
852 			break;
853 		case LRO_TYPE_NONE:
854 			switch (le->outer.data.lro_type) {
855 			case LRO_TYPE_IPV4_TCP:
856 				csum = tcp_lro_update_checksum(&le->outer, le,
857 				    le->m_head->m_pkthdr.lro_tcp_d_len,
858 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
859 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
860 				    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
861 				le->m_head->m_pkthdr.csum_data = 0xffff;
862 				if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
863 					le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
864 				break;
865 			case LRO_TYPE_IPV6_TCP:
866 				csum = tcp_lro_update_checksum(&le->outer, le,
867 				    le->m_head->m_pkthdr.lro_tcp_d_len,
868 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
869 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
870 				    CSUM_PSEUDO_HDR;
871 				le->m_head->m_pkthdr.csum_data = 0xffff;
872 				if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
873 					le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
874 				break;
875 			default:
876 				break;
877 			}
878 			break;
879 		default:
880 			break;
881 		}
882 	}
883 
884 	/*
885 	 * Break any chain, this is not set to NULL on the singleton
886 	 * case m_nextpkt points to m_head. Other case set them
887 	 * m_nextpkt to NULL in push_and_replace.
888 	 */
889 	le->m_head->m_nextpkt = NULL;
890 	lc->lro_queued += le->m_head->m_pkthdr.lro_nsegs;
891 	(*lc->ifp->if_input)(lc->ifp, le->m_head);
892 }
893 
894 static void
895 tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le,
896     struct mbuf *m, struct tcphdr *th)
897 {
898 	uint32_t *ts_ptr;
899 	uint16_t tcp_data_len;
900 	uint16_t tcp_opt_len;
901 
902 	ts_ptr = (uint32_t *)(th + 1);
903 	tcp_opt_len = (th->th_off << 2);
904 	tcp_opt_len -= sizeof(*th);
905 
906 	/* Check if there is a timestamp option. */
907 	if (tcp_opt_len == 0 ||
908 	    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
909 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
910 		/* We failed to find the timestamp option. */
911 		le->timestamp = 0;
912 	} else {
913 		le->timestamp = 1;
914 		le->tsval = ntohl(*(ts_ptr + 1));
915 		le->tsecr = *(ts_ptr + 2);
916 	}
917 
918 	tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
919 
920 	/* Pull out TCP sequence numbers and window size. */
921 	le->next_seq = ntohl(th->th_seq) + tcp_data_len;
922 	le->ack_seq = th->th_ack;
923 	le->window = th->th_win;
924 
925 	/* Setup new data pointers. */
926 	le->m_head = m;
927 	le->m_tail = m_last(m);
928 }
929 
930 static void
931 tcp_push_and_replace(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m)
932 {
933 	struct lro_parser *pa;
934 
935 	/*
936 	 * Push up the stack of the current entry
937 	 * and replace it with "m".
938 	 */
939 	struct mbuf *msave;
940 
941 	/* Grab off the next and save it */
942 	msave = le->m_head->m_nextpkt;
943 	le->m_head->m_nextpkt = NULL;
944 
945 	/* Now push out the old entry */
946 	tcp_flush_out_entry(lc, le);
947 
948 	/* Re-parse new header, should not fail. */
949 	pa = tcp_lro_parser(m, &le->outer, &le->inner, false);
950 	KASSERT(pa != NULL,
951 	    ("tcp_push_and_replace: LRO parser failed on m=%p\n", m));
952 
953 	/*
954 	 * Now to replace the data properly in the entry
955 	 * we have to reset the TCP header and
956 	 * other fields.
957 	 */
958 	tcp_set_entry_to_mbuf(lc, le, m, pa->tcp);
959 
960 	/* Restore the next list */
961 	m->m_nextpkt = msave;
962 }
963 
964 static void
965 tcp_lro_mbuf_append_pkthdr(struct mbuf *m, const struct mbuf *p)
966 {
967 	uint32_t csum;
968 
969 	if (m->m_pkthdr.lro_nsegs == 1) {
970 		/* Compute relative checksum. */
971 		csum = p->m_pkthdr.lro_tcp_d_csum;
972 	} else {
973 		/* Merge TCP data checksums. */
974 		csum = (uint32_t)m->m_pkthdr.lro_tcp_d_csum +
975 		    (uint32_t)p->m_pkthdr.lro_tcp_d_csum;
976 		while (csum > 0xffff)
977 			csum = (csum >> 16) + (csum & 0xffff);
978 	}
979 
980 	/* Update various counters. */
981 	m->m_pkthdr.len += p->m_pkthdr.lro_tcp_d_len;
982 	m->m_pkthdr.lro_tcp_d_csum = csum;
983 	m->m_pkthdr.lro_tcp_d_len += p->m_pkthdr.lro_tcp_d_len;
984 	m->m_pkthdr.lro_nsegs += p->m_pkthdr.lro_nsegs;
985 }
986 
987 static void
988 tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le)
989 {
990 	/*
991 	 * Walk through the mbuf chain we
992 	 * have on tap and compress/condense
993 	 * as required.
994 	 */
995 	uint32_t *ts_ptr;
996 	struct mbuf *m;
997 	struct tcphdr *th;
998 	uint32_t tcp_data_len_total;
999 	uint32_t tcp_data_seg_total;
1000 	uint16_t tcp_data_len;
1001 	uint16_t tcp_opt_len;
1002 
1003 	/*
1004 	 * First we must check the lead (m_head)
1005 	 * we must make sure that it is *not*
1006 	 * something that should be sent up
1007 	 * right away (sack etc).
1008 	 */
1009 again:
1010 	m = le->m_head->m_nextpkt;
1011 	if (m == NULL) {
1012 		/* Just one left. */
1013 		return;
1014 	}
1015 
1016 	th = tcp_lro_get_th(m);
1017 	tcp_opt_len = (th->th_off << 2);
1018 	tcp_opt_len -= sizeof(*th);
1019 	ts_ptr = (uint32_t *)(th + 1);
1020 
1021 	if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1022 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
1023 		/*
1024 		 * Its not the timestamp. We can't
1025 		 * use this guy as the head.
1026 		 */
1027 		le->m_head->m_nextpkt = m->m_nextpkt;
1028 		tcp_push_and_replace(lc, le, m);
1029 		goto again;
1030 	}
1031 	if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
1032 		/*
1033 		 * Make sure that previously seen segments/ACKs are delivered
1034 		 * before this segment, e.g. FIN.
1035 		 */
1036 		le->m_head->m_nextpkt = m->m_nextpkt;
1037 		tcp_push_and_replace(lc, le, m);
1038 		goto again;
1039 	}
1040 	while((m = le->m_head->m_nextpkt) != NULL) {
1041 		/*
1042 		 * condense m into le, first
1043 		 * pull m out of the list.
1044 		 */
1045 		le->m_head->m_nextpkt = m->m_nextpkt;
1046 		m->m_nextpkt = NULL;
1047 		/* Setup my data */
1048 		tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
1049 		th = tcp_lro_get_th(m);
1050 		ts_ptr = (uint32_t *)(th + 1);
1051 		tcp_opt_len = (th->th_off << 2);
1052 		tcp_opt_len -= sizeof(*th);
1053 		tcp_data_len_total = le->m_head->m_pkthdr.lro_tcp_d_len + tcp_data_len;
1054 		tcp_data_seg_total = le->m_head->m_pkthdr.lro_nsegs + m->m_pkthdr.lro_nsegs;
1055 
1056 		if (tcp_data_seg_total >= lc->lro_ackcnt_lim ||
1057 		    tcp_data_len_total >= lc->lro_length_lim) {
1058 			/* Flush now if appending will result in overflow. */
1059 			tcp_push_and_replace(lc, le, m);
1060 			goto again;
1061 		}
1062 		if (tcp_opt_len != 0 &&
1063 		    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1064 		    *ts_ptr != TCP_LRO_TS_OPTION)) {
1065 			/*
1066 			 * Maybe a sack in the new one? We need to
1067 			 * start all over after flushing the
1068 			 * current le. We will go up to the beginning
1069 			 * and flush it (calling the replace again possibly
1070 			 * or just returning).
1071 			 */
1072 			tcp_push_and_replace(lc, le, m);
1073 			goto again;
1074 		}
1075 		if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
1076 			tcp_push_and_replace(lc, le, m);
1077 			goto again;
1078 		}
1079 		if (tcp_opt_len != 0) {
1080 			uint32_t tsval = ntohl(*(ts_ptr + 1));
1081 			/* Make sure timestamp values are increasing. */
1082 			if (TSTMP_GT(le->tsval, tsval))  {
1083 				tcp_push_and_replace(lc, le, m);
1084 				goto again;
1085 			}
1086 			le->tsval = tsval;
1087 			le->tsecr = *(ts_ptr + 2);
1088 		}
1089 		/* Try to append the new segment. */
1090 		if (__predict_false(ntohl(th->th_seq) != le->next_seq ||
1091 				    (tcp_data_len == 0 &&
1092 				     le->ack_seq == th->th_ack &&
1093 				     le->window == th->th_win))) {
1094 			/* Out of order packet or duplicate ACK. */
1095 			tcp_push_and_replace(lc, le, m);
1096 			goto again;
1097 		}
1098 		if (tcp_data_len != 0 ||
1099 		    SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1100 			le->next_seq += tcp_data_len;
1101 			le->ack_seq = th->th_ack;
1102 			le->window = th->th_win;
1103 		} else if (th->th_ack == le->ack_seq) {
1104 			le->window = WIN_MAX(le->window, th->th_win);
1105 		}
1106 
1107 		if (tcp_data_len == 0) {
1108 			m_freem(m);
1109 			continue;
1110 		}
1111 
1112 		/* Merge TCP data checksum and length to head mbuf. */
1113 		tcp_lro_mbuf_append_pkthdr(le->m_head, m);
1114 
1115 		/*
1116 		 * Adjust the mbuf so that m_data points to the first byte of
1117 		 * the ULP payload.  Adjust the mbuf to avoid complications and
1118 		 * append new segment to existing mbuf chain.
1119 		 */
1120 		m_adj(m, m->m_pkthdr.len - tcp_data_len);
1121 		m_demote_pkthdr(m);
1122 		le->m_tail->m_next = m;
1123 		le->m_tail = m_last(m);
1124 	}
1125 }
1126 
1127 #ifdef TCPHPTS
1128 static void
1129 tcp_queue_pkts(struct inpcb *inp, struct tcpcb *tp, struct lro_entry *le)
1130 {
1131 	INP_WLOCK_ASSERT(inp);
1132 	if (tp->t_in_pkt == NULL) {
1133 		/* Nothing yet there */
1134 		tp->t_in_pkt = le->m_head;
1135 		tp->t_tail_pkt = le->m_last_mbuf;
1136 	} else {
1137 		/* Already some there */
1138 		tp->t_tail_pkt->m_nextpkt = le->m_head;
1139 		tp->t_tail_pkt = le->m_last_mbuf;
1140 	}
1141 	le->m_head = NULL;
1142 	le->m_last_mbuf = NULL;
1143 }
1144 
1145 static struct mbuf *
1146 tcp_lro_get_last_if_ackcmp(struct lro_ctrl *lc, struct lro_entry *le,
1147     struct inpcb *inp, int32_t *new_m)
1148 {
1149 	struct tcpcb *tp;
1150 	struct mbuf *m;
1151 
1152 	tp = intotcpcb(inp);
1153 	if (__predict_false(tp == NULL))
1154 		return (NULL);
1155 
1156 	/* Look at the last mbuf if any in queue */
1157 	m = tp->t_tail_pkt;
1158 	if (m != NULL && (m->m_flags & M_ACKCMP) != 0) {
1159 		if (M_TRAILINGSPACE(m) >= sizeof(struct tcp_ackent)) {
1160 			tcp_lro_log(tp, lc, le, NULL, 23, 0, 0, 0, 0);
1161 			*new_m = 0;
1162 			counter_u64_add(tcp_extra_mbuf, 1);
1163 			return (m);
1164 		} else {
1165 			/* Mark we ran out of space */
1166 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1167 		}
1168 	}
1169 	/* Decide mbuf size. */
1170 	if (inp->inp_flags2 & INP_MBUF_L_ACKS)
1171 		m = m_getcl(M_NOWAIT, MT_DATA, M_ACKCMP | M_PKTHDR);
1172 	else
1173 		m = m_gethdr(M_NOWAIT, MT_DATA);
1174 
1175 	if (__predict_false(m == NULL)) {
1176 		counter_u64_add(tcp_would_have_but, 1);
1177 		return (NULL);
1178 	}
1179 	counter_u64_add(tcp_comp_total, 1);
1180 	m->m_flags |= M_ACKCMP;
1181 	*new_m = 1;
1182 	return (m);
1183 }
1184 
1185 static struct inpcb *
1186 tcp_lro_lookup(struct ifnet *ifp, struct lro_parser *pa)
1187 {
1188 	struct inpcb *inp;
1189 
1190 	switch (pa->data.lro_type) {
1191 #ifdef INET6
1192 	case LRO_TYPE_IPV6_TCP:
1193 		inp = in6_pcblookup(&V_tcbinfo,
1194 		    &pa->data.s_addr.v6,
1195 		    pa->data.s_port,
1196 		    &pa->data.d_addr.v6,
1197 		    pa->data.d_port,
1198 		    INPLOOKUP_WLOCKPCB,
1199 		    ifp);
1200 		break;
1201 #endif
1202 #ifdef INET
1203 	case LRO_TYPE_IPV4_TCP:
1204 		inp = in_pcblookup(&V_tcbinfo,
1205 		    pa->data.s_addr.v4,
1206 		    pa->data.s_port,
1207 		    pa->data.d_addr.v4,
1208 		    pa->data.d_port,
1209 		    INPLOOKUP_WLOCKPCB,
1210 		    ifp);
1211 		break;
1212 #endif
1213 	default:
1214 		inp = NULL;
1215 		break;
1216 	}
1217 	return (inp);
1218 }
1219 
1220 static inline bool
1221 tcp_lro_ack_valid(struct mbuf *m, struct tcphdr *th, uint32_t **ppts, bool *other_opts)
1222 {
1223 	/*
1224 	 * This function returns two bits of valuable information.
1225 	 * a) Is what is present capable of being ack-compressed,
1226 	 *    we can ack-compress if there is no options or just
1227 	 *    a timestamp option, and of course the th_flags must
1228 	 *    be correct as well.
1229 	 * b) Our other options present such as SACK. This is
1230 	 *    used to determine if we want to wakeup or not.
1231 	 */
1232 	bool ret = true;
1233 
1234 	switch (th->th_off << 2) {
1235 	case (sizeof(*th) + TCPOLEN_TSTAMP_APPA):
1236 		*ppts = (uint32_t *)(th + 1);
1237 		/* Check if we have only one timestamp option. */
1238 		if (**ppts == TCP_LRO_TS_OPTION)
1239 			*other_opts = false;
1240 		else {
1241 			*other_opts = true;
1242 			ret = false;
1243 		}
1244 		break;
1245 	case (sizeof(*th)):
1246 		/* No options. */
1247 		*ppts = NULL;
1248 		*other_opts = false;
1249 		break;
1250 	default:
1251 		*ppts = NULL;
1252 		*other_opts = true;
1253 		ret = false;
1254 		break;
1255 	}
1256 	/* For ACKCMP we only accept ACK, PUSH, ECE and CWR. */
1257 	if ((th->th_flags & ~(TH_ACK | TH_PUSH | TH_ECE | TH_CWR)) != 0)
1258 		ret = false;
1259 	/* If it has data on it we cannot compress it */
1260 	if (m->m_pkthdr.lro_tcp_d_len)
1261 		ret = false;
1262 
1263 	/* ACK flag must be set. */
1264 	if (!(th->th_flags & TH_ACK))
1265 		ret = false;
1266 	return (ret);
1267 }
1268 
1269 static int
1270 tcp_lro_flush_tcphpts(struct lro_ctrl *lc, struct lro_entry *le)
1271 {
1272 	struct inpcb *inp;
1273 	struct tcpcb *tp;
1274 	struct mbuf **pp, *cmp, *mv_to;
1275 	bool bpf_req, should_wake;
1276 
1277 	/* Check if packet doesn't belongs to our network interface. */
1278 	if ((tcplro_stacks_wanting_mbufq == 0) ||
1279 	    (le->outer.data.vlan_id != 0) ||
1280 	    (le->inner.data.lro_type != LRO_TYPE_NONE))
1281 		return (TCP_LRO_CANNOT);
1282 
1283 #ifdef INET6
1284 	/*
1285 	 * Be proactive about unspecified IPv6 address in source. As
1286 	 * we use all-zero to indicate unbounded/unconnected pcb,
1287 	 * unspecified IPv6 address can be used to confuse us.
1288 	 *
1289 	 * Note that packets with unspecified IPv6 destination is
1290 	 * already dropped in ip6_input.
1291 	 */
1292 	if (__predict_false(le->outer.data.lro_type == LRO_TYPE_IPV6_TCP &&
1293 	    IN6_IS_ADDR_UNSPECIFIED(&le->outer.data.s_addr.v6)))
1294 		return (TCP_LRO_CANNOT);
1295 
1296 	if (__predict_false(le->inner.data.lro_type == LRO_TYPE_IPV6_TCP &&
1297 	    IN6_IS_ADDR_UNSPECIFIED(&le->inner.data.s_addr.v6)))
1298 		return (TCP_LRO_CANNOT);
1299 #endif
1300 	/* Lookup inp, if any. */
1301 	inp = tcp_lro_lookup(lc->ifp,
1302 	    (le->inner.data.lro_type == LRO_TYPE_NONE) ? &le->outer : &le->inner);
1303 	if (inp == NULL)
1304 		return (TCP_LRO_CANNOT);
1305 
1306 	counter_u64_add(tcp_inp_lro_locks_taken, 1);
1307 
1308 	/* Get TCP control structure. */
1309 	tp = intotcpcb(inp);
1310 
1311 	/* Check if the inp is dead, Jim. */
1312 	if (tp == NULL ||
1313 	    (inp->inp_flags & (INP_DROPPED | INP_TIMEWAIT))) {
1314 		INP_WUNLOCK(inp);
1315 		return (TCP_LRO_CANNOT);
1316 	}
1317 	if ((inp->inp_irq_cpu_set == 0)  && (lc->lro_cpu_is_set == 1)) {
1318 		inp->inp_irq_cpu = lc->lro_last_cpu;
1319 		inp->inp_irq_cpu_set = 1;
1320 	}
1321 	/* Check if the transport doesn't support the needed optimizations. */
1322 	if ((inp->inp_flags2 & (INP_SUPPORTS_MBUFQ | INP_MBUF_ACKCMP)) == 0) {
1323 		INP_WUNLOCK(inp);
1324 		return (TCP_LRO_CANNOT);
1325 	}
1326 
1327 	if (inp->inp_flags2 & INP_MBUF_QUEUE_READY)
1328 		should_wake = false;
1329 	else
1330 		should_wake = true;
1331 	/* Check if packets should be tapped to BPF. */
1332 	bpf_req = bpf_peers_present(lc->ifp->if_bpf);
1333 
1334 	/* Strip and compress all the incoming packets. */
1335 	cmp = NULL;
1336 	for (pp = &le->m_head; *pp != NULL; ) {
1337 		mv_to = NULL;
1338 		if (do_bpf_strip_and_compress(inp, lc, le, pp,
1339 			 &cmp, &mv_to, &should_wake, bpf_req ) == false) {
1340 			/* Advance to next mbuf. */
1341 			pp = &(*pp)->m_nextpkt;
1342 		} else if (mv_to != NULL) {
1343 			/* We are asked to move pp up */
1344 			pp = &mv_to->m_nextpkt;
1345 		}
1346 	}
1347 	/* Update "m_last_mbuf", if any. */
1348 	if (pp == &le->m_head)
1349 		le->m_last_mbuf = *pp;
1350 	else
1351 		le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
1352 
1353 	/* Check if any data mbufs left. */
1354 	if (le->m_head != NULL) {
1355 		counter_u64_add(tcp_inp_lro_direct_queue, 1);
1356 		tcp_lro_log(tp, lc, le, NULL, 22, 1,
1357 			    inp->inp_flags2, inp->inp_in_dropq, 1);
1358 		tcp_queue_pkts(inp, tp, le);
1359 	}
1360 	if (should_wake) {
1361 		/* Wakeup */
1362 		counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
1363 		if ((*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0))
1364 			inp = NULL;
1365 	}
1366 	if (inp != NULL)
1367 		INP_WUNLOCK(inp);
1368 	return (0);	/* Success. */
1369 }
1370 #endif
1371 
1372 void
1373 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
1374 {
1375 	/* Only optimise if there are multiple packets waiting. */
1376 #ifdef TCPHPTS
1377 	int error;
1378 #endif
1379 
1380 	NET_EPOCH_ASSERT();
1381 #ifdef TCPHPTS
1382 	CURVNET_SET(lc->ifp->if_vnet);
1383 	error = tcp_lro_flush_tcphpts(lc, le);
1384 	CURVNET_RESTORE();
1385 	if (error != 0) {
1386 #endif
1387 		tcp_lro_condense(lc, le);
1388 		tcp_flush_out_entry(lc, le);
1389 #ifdef TCPHPTS
1390 	}
1391 #endif
1392 	lc->lro_flushed++;
1393 	bzero(le, sizeof(*le));
1394 	LIST_INSERT_HEAD(&lc->lro_free, le, next);
1395 }
1396 
1397 #ifdef HAVE_INLINE_FLSLL
1398 #define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
1399 #else
1400 static inline uint64_t
1401 tcp_lro_msb_64(uint64_t x)
1402 {
1403 	x |= (x >> 1);
1404 	x |= (x >> 2);
1405 	x |= (x >> 4);
1406 	x |= (x >> 8);
1407 	x |= (x >> 16);
1408 	x |= (x >> 32);
1409 	return (x & ~(x >> 1));
1410 }
1411 #endif
1412 
1413 /*
1414  * The tcp_lro_sort() routine is comparable to qsort(), except it has
1415  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
1416  * number of elements to sort and 64 is the number of sequence bits
1417  * available. The algorithm is bit-slicing the 64-bit sequence number,
1418  * sorting one bit at a time from the most significant bit until the
1419  * least significant one, skipping the constant bits. This is
1420  * typically called a radix sort.
1421  */
1422 static void
1423 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
1424 {
1425 	struct lro_mbuf_sort temp;
1426 	uint64_t ones;
1427 	uint64_t zeros;
1428 	uint32_t x;
1429 	uint32_t y;
1430 
1431 repeat:
1432 	/* for small arrays insertion sort is faster */
1433 	if (size <= 12) {
1434 		for (x = 1; x < size; x++) {
1435 			temp = parray[x];
1436 			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
1437 				parray[y] = parray[y - 1];
1438 			parray[y] = temp;
1439 		}
1440 		return;
1441 	}
1442 
1443 	/* compute sequence bits which are constant */
1444 	ones = 0;
1445 	zeros = 0;
1446 	for (x = 0; x != size; x++) {
1447 		ones |= parray[x].seq;
1448 		zeros |= ~parray[x].seq;
1449 	}
1450 
1451 	/* compute bits which are not constant into "ones" */
1452 	ones &= zeros;
1453 	if (ones == 0)
1454 		return;
1455 
1456 	/* pick the most significant bit which is not constant */
1457 	ones = tcp_lro_msb_64(ones);
1458 
1459 	/*
1460 	 * Move entries having cleared sequence bits to the beginning
1461 	 * of the array:
1462 	 */
1463 	for (x = y = 0; y != size; y++) {
1464 		/* skip set bits */
1465 		if (parray[y].seq & ones)
1466 			continue;
1467 		/* swap entries */
1468 		temp = parray[x];
1469 		parray[x] = parray[y];
1470 		parray[y] = temp;
1471 		x++;
1472 	}
1473 
1474 	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
1475 
1476 	/* sort zeros */
1477 	tcp_lro_sort(parray, x);
1478 
1479 	/* sort ones */
1480 	parray += x;
1481 	size -= x;
1482 	goto repeat;
1483 }
1484 
1485 void
1486 tcp_lro_flush_all(struct lro_ctrl *lc)
1487 {
1488 	uint64_t seq;
1489 	uint64_t nseq;
1490 	unsigned x;
1491 
1492 	NET_EPOCH_ASSERT();
1493 	/* check if no mbufs to flush */
1494 	if (lc->lro_mbuf_count == 0)
1495 		goto done;
1496 	if (lc->lro_cpu_is_set == 0) {
1497 		if (lc->lro_last_cpu == curcpu) {
1498 			lc->lro_cnt_of_same_cpu++;
1499 			/* Have we reached the threshold to declare a cpu? */
1500 			if (lc->lro_cnt_of_same_cpu > tcp_lro_cpu_set_thresh)
1501 				lc->lro_cpu_is_set = 1;
1502 		} else {
1503 			lc->lro_last_cpu = curcpu;
1504 			lc->lro_cnt_of_same_cpu = 0;
1505 		}
1506 	}
1507 	CURVNET_SET(lc->ifp->if_vnet);
1508 
1509 	/* get current time */
1510 	binuptime(&lc->lro_last_queue_time);
1511 
1512 	/* sort all mbufs according to stream */
1513 	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
1514 
1515 	/* input data into LRO engine, stream by stream */
1516 	seq = 0;
1517 	for (x = 0; x != lc->lro_mbuf_count; x++) {
1518 		struct mbuf *mb;
1519 
1520 		/* get mbuf */
1521 		mb = lc->lro_mbuf_data[x].mb;
1522 
1523 		/* get sequence number, masking away the packet index */
1524 		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
1525 
1526 		/* check for new stream */
1527 		if (seq != nseq) {
1528 			seq = nseq;
1529 
1530 			/* flush active streams */
1531 			tcp_lro_rx_done(lc);
1532 		}
1533 
1534 		/* add packet to LRO engine */
1535 		if (tcp_lro_rx_common(lc, mb, 0, false) != 0) {
1536 			/* input packet to network layer */
1537 			(*lc->ifp->if_input)(lc->ifp, mb);
1538 			lc->lro_queued++;
1539 			lc->lro_flushed++;
1540 		}
1541 	}
1542 	CURVNET_RESTORE();
1543 done:
1544 	/* flush active streams */
1545 	tcp_lro_rx_done(lc);
1546 
1547 #ifdef TCPHPTS
1548 	tcp_run_hpts();
1549 #endif
1550 	lc->lro_mbuf_count = 0;
1551 }
1552 
1553 #ifdef TCPHPTS
1554 static void
1555 build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
1556     uint32_t *ts_ptr, uint16_t iptos)
1557 {
1558 	/*
1559 	 * Given a TCP ACK, summarize it down into the small TCP ACK
1560 	 * entry.
1561 	 */
1562 	ae->timestamp = m->m_pkthdr.rcv_tstmp;
1563 	if (m->m_flags & M_TSTMP_LRO)
1564 		ae->flags = TSTMP_LRO;
1565 	else if (m->m_flags & M_TSTMP)
1566 		ae->flags = TSTMP_HDWR;
1567 	ae->seq = ntohl(th->th_seq);
1568 	ae->ack = ntohl(th->th_ack);
1569 	ae->flags |= th->th_flags;
1570 	if (ts_ptr != NULL) {
1571 		ae->ts_value = ntohl(ts_ptr[1]);
1572 		ae->ts_echo = ntohl(ts_ptr[2]);
1573 		ae->flags |= HAS_TSTMP;
1574 	}
1575 	ae->win = ntohs(th->th_win);
1576 	ae->codepoint = iptos;
1577 }
1578 
1579 /*
1580  * Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
1581  * and strip all, but the IPv4/IPv6 header.
1582  */
1583 static bool
1584 do_bpf_strip_and_compress(struct inpcb *inp, struct lro_ctrl *lc,
1585     struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp, struct mbuf **mv_to,
1586     bool *should_wake, bool bpf_req)
1587 {
1588 	union {
1589 		void *ptr;
1590 		struct ip *ip4;
1591 		struct ip6_hdr *ip6;
1592 	} l3;
1593 	struct mbuf *m;
1594 	struct mbuf *nm;
1595 	struct tcphdr *th;
1596 	struct tcp_ackent *ack_ent;
1597 	uint32_t *ts_ptr;
1598 	int32_t n_mbuf;
1599 	bool other_opts, can_compress;
1600 	uint8_t lro_type;
1601 	uint16_t iptos;
1602 	int tcp_hdr_offset;
1603 	int idx;
1604 
1605 	/* Get current mbuf. */
1606 	m = *pp;
1607 
1608 	/* Let the BPF see the packet */
1609 	if (__predict_false(bpf_req))
1610 		ETHER_BPF_MTAP(lc->ifp, m);
1611 
1612 	tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
1613 	lro_type = le->inner.data.lro_type;
1614 	switch (lro_type) {
1615 	case LRO_TYPE_NONE:
1616 		lro_type = le->outer.data.lro_type;
1617 		switch (lro_type) {
1618 		case LRO_TYPE_IPV4_TCP:
1619 			tcp_hdr_offset -= sizeof(*le->outer.ip4);
1620 			m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1621 			break;
1622 		case LRO_TYPE_IPV6_TCP:
1623 			tcp_hdr_offset -= sizeof(*le->outer.ip6);
1624 			m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1625 			break;
1626 		default:
1627 			goto compressed;
1628 		}
1629 		break;
1630 	case LRO_TYPE_IPV4_TCP:
1631 		tcp_hdr_offset -= sizeof(*le->outer.ip4);
1632 		m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1633 		break;
1634 	case LRO_TYPE_IPV6_TCP:
1635 		tcp_hdr_offset -= sizeof(*le->outer.ip6);
1636 		m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1637 		break;
1638 	default:
1639 		goto compressed;
1640 	}
1641 
1642 	MPASS(tcp_hdr_offset >= 0);
1643 
1644 	m_adj(m, tcp_hdr_offset);
1645 	m->m_flags |= M_LRO_EHDRSTRP;
1646 	m->m_flags &= ~M_ACKCMP;
1647 	m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
1648 
1649 	th = tcp_lro_get_th(m);
1650 
1651 	th->th_sum = 0;		/* TCP checksum is valid. */
1652 
1653 	/* Check if ACK can be compressed */
1654 	can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
1655 
1656 	/* Now lets look at the should wake states */
1657 	if ((other_opts == true) &&
1658 	    ((inp->inp_flags2 & INP_DONT_SACK_QUEUE) == 0)) {
1659 		/*
1660 		 * If there are other options (SACK?) and the
1661 		 * tcp endpoint has not expressly told us it does
1662 		 * not care about SACKS, then we should wake up.
1663 		 */
1664 		*should_wake = true;
1665 	}
1666 	/* Is the ack compressable? */
1667 	if (can_compress == false)
1668 		goto done;
1669 	/* Does the TCP endpoint support ACK compression? */
1670 	if ((inp->inp_flags2 & INP_MBUF_ACKCMP) == 0)
1671 		goto done;
1672 
1673 	/* Lets get the TOS/traffic class field */
1674 	l3.ptr = mtod(m, void *);
1675 	switch (lro_type) {
1676 	case LRO_TYPE_IPV4_TCP:
1677 		iptos = l3.ip4->ip_tos;
1678 		break;
1679 	case LRO_TYPE_IPV6_TCP:
1680 		iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
1681 		break;
1682 	default:
1683 		iptos = 0;	/* Keep compiler happy. */
1684 		break;
1685 	}
1686 	/* Now lets get space if we don't have some already */
1687 	if (*cmp == NULL) {
1688 new_one:
1689 		nm = tcp_lro_get_last_if_ackcmp(lc, le, inp, &n_mbuf);
1690 		if (__predict_false(nm == NULL))
1691 			goto done;
1692 		*cmp = nm;
1693 		if (n_mbuf) {
1694 			/*
1695 			 *  Link in the new cmp ack to our in-order place,
1696 			 * first set our cmp ack's next to where we are.
1697 			 */
1698 			nm->m_nextpkt = m;
1699 			(*pp) = nm;
1700 			/*
1701 			 * Set it up so mv_to is advanced to our
1702 			 * compressed ack. This way the caller can
1703 			 * advance pp to the right place.
1704 			 */
1705 			*mv_to = nm;
1706 			/*
1707 			 * Advance it here locally as well.
1708 			 */
1709 			pp = &nm->m_nextpkt;
1710 		}
1711 	} else {
1712 		/* We have one already we are working on */
1713 		nm = *cmp;
1714 		if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
1715 			/* We ran out of space */
1716 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1717 			goto new_one;
1718 		}
1719 	}
1720 	MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
1721 	counter_u64_add(tcp_inp_lro_compressed, 1);
1722 	le->compressed++;
1723 	/* We can add in to the one on the tail */
1724 	ack_ent = mtod(nm, struct tcp_ackent *);
1725 	idx = (nm->m_len / sizeof(struct tcp_ackent));
1726 	build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
1727 
1728 	/* Bump the size of both pkt-hdr and len */
1729 	nm->m_len += sizeof(struct tcp_ackent);
1730 	nm->m_pkthdr.len += sizeof(struct tcp_ackent);
1731 compressed:
1732 	/* Advance to next mbuf before freeing. */
1733 	*pp = m->m_nextpkt;
1734 	m->m_nextpkt = NULL;
1735 	m_freem(m);
1736 	return (true);
1737 done:
1738 	counter_u64_add(tcp_uncomp_total, 1);
1739 	le->uncompressed++;
1740 	return (false);
1741 }
1742 #endif
1743 
1744 static struct lro_head *
1745 tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser)
1746 {
1747 	u_long hash;
1748 
1749 	if (M_HASHTYPE_ISHASH(m)) {
1750 		hash = m->m_pkthdr.flowid;
1751 	} else {
1752 		for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++)
1753 			hash += parser->data.raw[i];
1754 	}
1755 	return (&lc->lro_hash[hash % lc->lro_hashsz]);
1756 }
1757 
1758 static int
1759 tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash)
1760 {
1761 	struct lro_parser pi;	/* inner address data */
1762 	struct lro_parser po;	/* outer address data */
1763 	struct lro_parser *pa;	/* current parser for TCP stream */
1764 	struct lro_entry *le;
1765 	struct lro_head *bucket;
1766 	struct tcphdr *th;
1767 	int tcp_data_len;
1768 	int tcp_opt_len;
1769 	int error;
1770 	uint16_t tcp_data_sum;
1771 
1772 #ifdef INET
1773 	/* Quickly decide if packet cannot be LRO'ed */
1774 	if (__predict_false(V_ipforwarding != 0))
1775 		return (TCP_LRO_CANNOT);
1776 #endif
1777 #ifdef INET6
1778 	/* Quickly decide if packet cannot be LRO'ed */
1779 	if (__predict_false(V_ip6_forwarding != 0))
1780 		return (TCP_LRO_CANNOT);
1781 #endif
1782 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1783 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1784 	    (m->m_pkthdr.csum_data != 0xffff)) {
1785 		/*
1786 		 * The checksum either did not have hardware offload
1787 		 * or it was a bad checksum. We can't LRO such
1788 		 * a packet.
1789 		 */
1790 		counter_u64_add(tcp_bad_csums, 1);
1791 		return (TCP_LRO_CANNOT);
1792 	}
1793 	/* We expect a contiguous header [eh, ip, tcp]. */
1794 	pa = tcp_lro_parser(m, &po, &pi, true);
1795 	if (__predict_false(pa == NULL))
1796 		return (TCP_LRO_NOT_SUPPORTED);
1797 
1798 	/* We don't expect any padding. */
1799 	error = tcp_lro_trim_mbuf_chain(m, pa);
1800 	if (__predict_false(error != 0))
1801 		return (error);
1802 
1803 #ifdef INET
1804 	switch (pa->data.lro_type) {
1805 	case LRO_TYPE_IPV4_TCP:
1806 		error = tcp_lro_rx_ipv4(lc, m, pa->ip4);
1807 		if (__predict_false(error != 0))
1808 			return (error);
1809 		break;
1810 	default:
1811 		break;
1812 	}
1813 #endif
1814 	/* If no hardware or arrival stamp on the packet add timestamp */
1815 	if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
1816 		m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
1817 		m->m_flags |= M_TSTMP_LRO;
1818 	}
1819 
1820 	/* Get pointer to TCP header. */
1821 	th = pa->tcp;
1822 
1823 	/* Don't process SYN packets. */
1824 	if (__predict_false(th->th_flags & TH_SYN))
1825 		return (TCP_LRO_CANNOT);
1826 
1827 	/* Get total TCP header length and compute payload length. */
1828 	tcp_opt_len = (th->th_off << 2);
1829 	tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th -
1830 	    (uint8_t *)m->m_data) - tcp_opt_len;
1831 	tcp_opt_len -= sizeof(*th);
1832 
1833 	/* Don't process invalid TCP headers. */
1834 	if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0))
1835 		return (TCP_LRO_CANNOT);
1836 
1837 	/* Compute TCP data only checksum. */
1838 	if (tcp_data_len == 0)
1839 		tcp_data_sum = 0;	/* no data, no checksum */
1840 	else if (__predict_false(csum != 0))
1841 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum);
1842 	else
1843 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum);
1844 
1845 	/* Save TCP info in mbuf. */
1846 	m->m_nextpkt = NULL;
1847 	m->m_pkthdr.rcvif = lc->ifp;
1848 	m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum;
1849 	m->m_pkthdr.lro_tcp_d_len = tcp_data_len;
1850 	m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data);
1851 	m->m_pkthdr.lro_nsegs = 1;
1852 
1853 	/* Get hash bucket. */
1854 	if (!use_hash) {
1855 		bucket = &lc->lro_hash[0];
1856 	} else {
1857 		bucket = tcp_lro_rx_get_bucket(lc, m, pa);
1858 	}
1859 
1860 	/* Try to find a matching previous segment. */
1861 	LIST_FOREACH(le, bucket, hash_next) {
1862 		/* Compare addresses and ports. */
1863 		if (lro_address_compare(&po.data, &le->outer.data) == false ||
1864 		    lro_address_compare(&pi.data, &le->inner.data) == false)
1865 			continue;
1866 
1867 		/* Check if no data and old ACK. */
1868 		if (tcp_data_len == 0 &&
1869 		    SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1870 			m_freem(m);
1871 			return (0);
1872 		}
1873 
1874 		/* Mark "m" in the last spot. */
1875 		le->m_last_mbuf->m_nextpkt = m;
1876 		/* Now set the tail to "m". */
1877 		le->m_last_mbuf = m;
1878 		return (0);
1879 	}
1880 
1881 	/* Try to find an empty slot. */
1882 	if (LIST_EMPTY(&lc->lro_free))
1883 		return (TCP_LRO_NO_ENTRIES);
1884 
1885 	/* Start a new segment chain. */
1886 	le = LIST_FIRST(&lc->lro_free);
1887 	LIST_REMOVE(le, next);
1888 	tcp_lro_active_insert(lc, bucket, le);
1889 
1890 	/* Make sure the headers are set. */
1891 	le->inner = pi;
1892 	le->outer = po;
1893 
1894 	/* Store time this entry was allocated. */
1895 	le->alloc_time = lc->lro_last_queue_time;
1896 
1897 	tcp_set_entry_to_mbuf(lc, le, m, th);
1898 
1899 	/* Now set the tail to "m". */
1900 	le->m_last_mbuf = m;
1901 
1902 	return (0);
1903 }
1904 
1905 int
1906 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
1907 {
1908 	int error;
1909 
1910 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1911 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1912 	    (m->m_pkthdr.csum_data != 0xffff)) {
1913 		/*
1914 		 * The checksum either did not have hardware offload
1915 		 * or it was a bad checksum. We can't LRO such
1916 		 * a packet.
1917 		 */
1918 		counter_u64_add(tcp_bad_csums, 1);
1919 		return (TCP_LRO_CANNOT);
1920 	}
1921 	/* get current time */
1922 	binuptime(&lc->lro_last_queue_time);
1923 	CURVNET_SET(lc->ifp->if_vnet);
1924 	error = tcp_lro_rx_common(lc, m, csum, true);
1925 	CURVNET_RESTORE();
1926 
1927 	return (error);
1928 }
1929 
1930 void
1931 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
1932 {
1933 	NET_EPOCH_ASSERT();
1934 	/* sanity checks */
1935 	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
1936 	    lc->lro_mbuf_max == 0)) {
1937 		/* packet drop */
1938 		m_freem(mb);
1939 		return;
1940 	}
1941 
1942 	/* check if packet is not LRO capable */
1943 	if (__predict_false((lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
1944 		/* input packet to network layer */
1945 		(*lc->ifp->if_input) (lc->ifp, mb);
1946 		return;
1947 	}
1948 
1949 	/* create sequence number */
1950 	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
1951 	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
1952 	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
1953 	    ((uint64_t)lc->lro_mbuf_count);
1954 
1955 	/* enter mbuf */
1956 	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
1957 
1958 	/* flush if array is full */
1959 	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
1960 		tcp_lro_flush_all(lc);
1961 }
1962 
1963 /* end */
1964