xref: /freebsd/sys/netinet/tcp_lro.c (revision f7c32ed617858bcd22f8d1b03199099d50125721)
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 segements/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->inp_flags2 & INP_FREED)) {
1315 		INP_WUNLOCK(inp);
1316 		return (TCP_LRO_CANNOT);
1317 	}
1318 	if ((inp->inp_irq_cpu_set == 0)  && (lc->lro_cpu_is_set == 1)) {
1319 		inp->inp_irq_cpu = lc->lro_last_cpu;
1320 		inp->inp_irq_cpu_set = 1;
1321 	}
1322 	/* Check if the transport doesn't support the needed optimizations. */
1323 	if ((inp->inp_flags2 & (INP_SUPPORTS_MBUFQ | INP_MBUF_ACKCMP)) == 0) {
1324 		INP_WUNLOCK(inp);
1325 		return (TCP_LRO_CANNOT);
1326 	}
1327 
1328 	if (inp->inp_flags2 & INP_MBUF_QUEUE_READY)
1329 		should_wake = false;
1330 	else
1331 		should_wake = true;
1332 	/* Check if packets should be tapped to BPF. */
1333 	bpf_req = bpf_peers_present(lc->ifp->if_bpf);
1334 
1335 	/* Strip and compress all the incoming packets. */
1336 	cmp = NULL;
1337 	for (pp = &le->m_head; *pp != NULL; ) {
1338 		mv_to = NULL;
1339 		if (do_bpf_strip_and_compress(inp, lc, le, pp,
1340 			 &cmp, &mv_to, &should_wake, bpf_req ) == false) {
1341 			/* Advance to next mbuf. */
1342 			pp = &(*pp)->m_nextpkt;
1343 		} else if (mv_to != NULL) {
1344 			/* We are asked to move pp up */
1345 			pp = &mv_to->m_nextpkt;
1346 		}
1347 	}
1348 	/* Update "m_last_mbuf", if any. */
1349 	if (pp == &le->m_head)
1350 		le->m_last_mbuf = *pp;
1351 	else
1352 		le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
1353 
1354 	/* Check if any data mbufs left. */
1355 	if (le->m_head != NULL) {
1356 		counter_u64_add(tcp_inp_lro_direct_queue, 1);
1357 		tcp_lro_log(tp, lc, le, NULL, 22, 1,
1358 			    inp->inp_flags2, inp->inp_in_input, 1);
1359 		tcp_queue_pkts(inp, tp, le);
1360 	}
1361 	if (should_wake) {
1362 		/* Wakeup */
1363 		counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
1364 		if ((*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0))
1365 			inp = NULL;
1366 	}
1367 	if (inp != NULL)
1368 		INP_WUNLOCK(inp);
1369 	return (0);	/* Success. */
1370 }
1371 #endif
1372 
1373 void
1374 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
1375 {
1376 	/* Only optimise if there are multiple packets waiting. */
1377 #ifdef TCPHPTS
1378 	int error;
1379 #endif
1380 
1381 	NET_EPOCH_ASSERT();
1382 #ifdef TCPHPTS
1383 	CURVNET_SET(lc->ifp->if_vnet);
1384 	error = tcp_lro_flush_tcphpts(lc, le);
1385 	CURVNET_RESTORE();
1386 	if (error != 0) {
1387 #endif
1388 		tcp_lro_condense(lc, le);
1389 		tcp_flush_out_entry(lc, le);
1390 #ifdef TCPHPTS
1391 	}
1392 #endif
1393 	lc->lro_flushed++;
1394 	bzero(le, sizeof(*le));
1395 	LIST_INSERT_HEAD(&lc->lro_free, le, next);
1396 }
1397 
1398 #ifdef HAVE_INLINE_FLSLL
1399 #define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
1400 #else
1401 static inline uint64_t
1402 tcp_lro_msb_64(uint64_t x)
1403 {
1404 	x |= (x >> 1);
1405 	x |= (x >> 2);
1406 	x |= (x >> 4);
1407 	x |= (x >> 8);
1408 	x |= (x >> 16);
1409 	x |= (x >> 32);
1410 	return (x & ~(x >> 1));
1411 }
1412 #endif
1413 
1414 /*
1415  * The tcp_lro_sort() routine is comparable to qsort(), except it has
1416  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
1417  * number of elements to sort and 64 is the number of sequence bits
1418  * available. The algorithm is bit-slicing the 64-bit sequence number,
1419  * sorting one bit at a time from the most significant bit until the
1420  * least significant one, skipping the constant bits. This is
1421  * typically called a radix sort.
1422  */
1423 static void
1424 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
1425 {
1426 	struct lro_mbuf_sort temp;
1427 	uint64_t ones;
1428 	uint64_t zeros;
1429 	uint32_t x;
1430 	uint32_t y;
1431 
1432 repeat:
1433 	/* for small arrays insertion sort is faster */
1434 	if (size <= 12) {
1435 		for (x = 1; x < size; x++) {
1436 			temp = parray[x];
1437 			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
1438 				parray[y] = parray[y - 1];
1439 			parray[y] = temp;
1440 		}
1441 		return;
1442 	}
1443 
1444 	/* compute sequence bits which are constant */
1445 	ones = 0;
1446 	zeros = 0;
1447 	for (x = 0; x != size; x++) {
1448 		ones |= parray[x].seq;
1449 		zeros |= ~parray[x].seq;
1450 	}
1451 
1452 	/* compute bits which are not constant into "ones" */
1453 	ones &= zeros;
1454 	if (ones == 0)
1455 		return;
1456 
1457 	/* pick the most significant bit which is not constant */
1458 	ones = tcp_lro_msb_64(ones);
1459 
1460 	/*
1461 	 * Move entries having cleared sequence bits to the beginning
1462 	 * of the array:
1463 	 */
1464 	for (x = y = 0; y != size; y++) {
1465 		/* skip set bits */
1466 		if (parray[y].seq & ones)
1467 			continue;
1468 		/* swap entries */
1469 		temp = parray[x];
1470 		parray[x] = parray[y];
1471 		parray[y] = temp;
1472 		x++;
1473 	}
1474 
1475 	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
1476 
1477 	/* sort zeros */
1478 	tcp_lro_sort(parray, x);
1479 
1480 	/* sort ones */
1481 	parray += x;
1482 	size -= x;
1483 	goto repeat;
1484 }
1485 
1486 void
1487 tcp_lro_flush_all(struct lro_ctrl *lc)
1488 {
1489 	uint64_t seq;
1490 	uint64_t nseq;
1491 	unsigned x;
1492 
1493 	NET_EPOCH_ASSERT();
1494 	/* check if no mbufs to flush */
1495 	if (lc->lro_mbuf_count == 0)
1496 		goto done;
1497 	if (lc->lro_cpu_is_set == 0) {
1498 		if (lc->lro_last_cpu == curcpu) {
1499 			lc->lro_cnt_of_same_cpu++;
1500 			/* Have we reached the threshold to declare a cpu? */
1501 			if (lc->lro_cnt_of_same_cpu > tcp_lro_cpu_set_thresh)
1502 				lc->lro_cpu_is_set = 1;
1503 		} else {
1504 			lc->lro_last_cpu = curcpu;
1505 			lc->lro_cnt_of_same_cpu = 0;
1506 		}
1507 	}
1508 	CURVNET_SET(lc->ifp->if_vnet);
1509 
1510 	/* get current time */
1511 	binuptime(&lc->lro_last_queue_time);
1512 
1513 	/* sort all mbufs according to stream */
1514 	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
1515 
1516 	/* input data into LRO engine, stream by stream */
1517 	seq = 0;
1518 	for (x = 0; x != lc->lro_mbuf_count; x++) {
1519 		struct mbuf *mb;
1520 
1521 		/* get mbuf */
1522 		mb = lc->lro_mbuf_data[x].mb;
1523 
1524 		/* get sequence number, masking away the packet index */
1525 		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
1526 
1527 		/* check for new stream */
1528 		if (seq != nseq) {
1529 			seq = nseq;
1530 
1531 			/* flush active streams */
1532 			tcp_lro_rx_done(lc);
1533 		}
1534 
1535 		/* add packet to LRO engine */
1536 		if (tcp_lro_rx_common(lc, mb, 0, false) != 0) {
1537 			/* input packet to network layer */
1538 			(*lc->ifp->if_input)(lc->ifp, mb);
1539 			lc->lro_queued++;
1540 			lc->lro_flushed++;
1541 		}
1542 	}
1543 	CURVNET_RESTORE();
1544 done:
1545 	/* flush active streams */
1546 	tcp_lro_rx_done(lc);
1547 
1548 #ifdef TCPHPTS
1549 	tcp_run_hpts();
1550 #endif
1551 	lc->lro_mbuf_count = 0;
1552 }
1553 
1554 #ifdef TCPHPTS
1555 static void
1556 build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
1557     uint32_t *ts_ptr, uint16_t iptos)
1558 {
1559 	/*
1560 	 * Given a TCP ACK, summarize it down into the small TCP ACK
1561 	 * entry.
1562 	 */
1563 	ae->timestamp = m->m_pkthdr.rcv_tstmp;
1564 	if (m->m_flags & M_TSTMP_LRO)
1565 		ae->flags = TSTMP_LRO;
1566 	else if (m->m_flags & M_TSTMP)
1567 		ae->flags = TSTMP_HDWR;
1568 	ae->seq = ntohl(th->th_seq);
1569 	ae->ack = ntohl(th->th_ack);
1570 	ae->flags |= th->th_flags;
1571 	if (ts_ptr != NULL) {
1572 		ae->ts_value = ntohl(ts_ptr[1]);
1573 		ae->ts_echo = ntohl(ts_ptr[2]);
1574 		ae->flags |= HAS_TSTMP;
1575 	}
1576 	ae->win = ntohs(th->th_win);
1577 	ae->codepoint = iptos;
1578 }
1579 
1580 /*
1581  * Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
1582  * and strip all, but the IPv4/IPv6 header.
1583  */
1584 static bool
1585 do_bpf_strip_and_compress(struct inpcb *inp, struct lro_ctrl *lc,
1586     struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp, struct mbuf **mv_to,
1587     bool *should_wake, bool bpf_req)
1588 {
1589 	union {
1590 		void *ptr;
1591 		struct ip *ip4;
1592 		struct ip6_hdr *ip6;
1593 	} l3;
1594 	struct mbuf *m;
1595 	struct mbuf *nm;
1596 	struct tcphdr *th;
1597 	struct tcp_ackent *ack_ent;
1598 	uint32_t *ts_ptr;
1599 	int32_t n_mbuf;
1600 	bool other_opts, can_compress;
1601 	uint8_t lro_type;
1602 	uint16_t iptos;
1603 	int tcp_hdr_offset;
1604 	int idx;
1605 
1606 	/* Get current mbuf. */
1607 	m = *pp;
1608 
1609 	/* Let the BPF see the packet */
1610 	if (__predict_false(bpf_req))
1611 		ETHER_BPF_MTAP(lc->ifp, m);
1612 
1613 	tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
1614 	lro_type = le->inner.data.lro_type;
1615 	switch (lro_type) {
1616 	case LRO_TYPE_NONE:
1617 		lro_type = le->outer.data.lro_type;
1618 		switch (lro_type) {
1619 		case LRO_TYPE_IPV4_TCP:
1620 			tcp_hdr_offset -= sizeof(*le->outer.ip4);
1621 			m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1622 			break;
1623 		case LRO_TYPE_IPV6_TCP:
1624 			tcp_hdr_offset -= sizeof(*le->outer.ip6);
1625 			m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1626 			break;
1627 		default:
1628 			goto compressed;
1629 		}
1630 		break;
1631 	case LRO_TYPE_IPV4_TCP:
1632 		tcp_hdr_offset -= sizeof(*le->outer.ip4);
1633 		m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1634 		break;
1635 	case LRO_TYPE_IPV6_TCP:
1636 		tcp_hdr_offset -= sizeof(*le->outer.ip6);
1637 		m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1638 		break;
1639 	default:
1640 		goto compressed;
1641 	}
1642 
1643 	MPASS(tcp_hdr_offset >= 0);
1644 
1645 	m_adj(m, tcp_hdr_offset);
1646 	m->m_flags |= M_LRO_EHDRSTRP;
1647 	m->m_flags &= ~M_ACKCMP;
1648 	m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
1649 
1650 	th = tcp_lro_get_th(m);
1651 
1652 	th->th_sum = 0;		/* TCP checksum is valid. */
1653 
1654 	/* Check if ACK can be compressed */
1655 	can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
1656 
1657 	/* Now lets look at the should wake states */
1658 	if ((other_opts == true) &&
1659 	    ((inp->inp_flags2 & INP_DONT_SACK_QUEUE) == 0)) {
1660 		/*
1661 		 * If there are other options (SACK?) and the
1662 		 * tcp endpoint has not expressly told us it does
1663 		 * not care about SACKS, then we should wake up.
1664 		 */
1665 		*should_wake = true;
1666 	}
1667 	/* Is the ack compressable? */
1668 	if (can_compress == false)
1669 		goto done;
1670 	/* Does the TCP endpoint support ACK compression? */
1671 	if ((inp->inp_flags2 & INP_MBUF_ACKCMP) == 0)
1672 		goto done;
1673 
1674 	/* Lets get the TOS/traffic class field */
1675 	l3.ptr = mtod(m, void *);
1676 	switch (lro_type) {
1677 	case LRO_TYPE_IPV4_TCP:
1678 		iptos = l3.ip4->ip_tos;
1679 		break;
1680 	case LRO_TYPE_IPV6_TCP:
1681 		iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
1682 		break;
1683 	default:
1684 		iptos = 0;	/* Keep compiler happy. */
1685 		break;
1686 	}
1687 	/* Now lets get space if we don't have some already */
1688 	if (*cmp == NULL) {
1689 new_one:
1690 		nm = tcp_lro_get_last_if_ackcmp(lc, le, inp, &n_mbuf);
1691 		if (__predict_false(nm == NULL))
1692 			goto done;
1693 		*cmp = nm;
1694 		if (n_mbuf) {
1695 			/*
1696 			 *  Link in the new cmp ack to our in-order place,
1697 			 * first set our cmp ack's next to where we are.
1698 			 */
1699 			nm->m_nextpkt = m;
1700 			(*pp) = nm;
1701 			/*
1702 			 * Set it up so mv_to is advanced to our
1703 			 * compressed ack. This way the caller can
1704 			 * advance pp to the right place.
1705 			 */
1706 			*mv_to = nm;
1707 			/*
1708 			 * Advance it here locally as well.
1709 			 */
1710 			pp = &nm->m_nextpkt;
1711 		}
1712 	} else {
1713 		/* We have one already we are working on */
1714 		nm = *cmp;
1715 		if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
1716 			/* We ran out of space */
1717 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1718 			goto new_one;
1719 		}
1720 	}
1721 	MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
1722 	counter_u64_add(tcp_inp_lro_compressed, 1);
1723 	le->compressed++;
1724 	/* We can add in to the one on the tail */
1725 	ack_ent = mtod(nm, struct tcp_ackent *);
1726 	idx = (nm->m_len / sizeof(struct tcp_ackent));
1727 	build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
1728 
1729 	/* Bump the size of both pkt-hdr and len */
1730 	nm->m_len += sizeof(struct tcp_ackent);
1731 	nm->m_pkthdr.len += sizeof(struct tcp_ackent);
1732 compressed:
1733 	/* Advance to next mbuf before freeing. */
1734 	*pp = m->m_nextpkt;
1735 	m->m_nextpkt = NULL;
1736 	m_freem(m);
1737 	return (true);
1738 done:
1739 	counter_u64_add(tcp_uncomp_total, 1);
1740 	le->uncompressed++;
1741 	return (false);
1742 }
1743 #endif
1744 
1745 static struct lro_head *
1746 tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser)
1747 {
1748 	u_long hash;
1749 
1750 	if (M_HASHTYPE_ISHASH(m)) {
1751 		hash = m->m_pkthdr.flowid;
1752 	} else {
1753 		for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++)
1754 			hash += parser->data.raw[i];
1755 	}
1756 	return (&lc->lro_hash[hash % lc->lro_hashsz]);
1757 }
1758 
1759 static int
1760 tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash)
1761 {
1762 	struct lro_parser pi;	/* inner address data */
1763 	struct lro_parser po;	/* outer address data */
1764 	struct lro_parser *pa;	/* current parser for TCP stream */
1765 	struct lro_entry *le;
1766 	struct lro_head *bucket;
1767 	struct tcphdr *th;
1768 	int tcp_data_len;
1769 	int tcp_opt_len;
1770 	int error;
1771 	uint16_t tcp_data_sum;
1772 
1773 #ifdef INET
1774 	/* Quickly decide if packet cannot be LRO'ed */
1775 	if (__predict_false(V_ipforwarding != 0))
1776 		return (TCP_LRO_CANNOT);
1777 #endif
1778 #ifdef INET6
1779 	/* Quickly decide if packet cannot be LRO'ed */
1780 	if (__predict_false(V_ip6_forwarding != 0))
1781 		return (TCP_LRO_CANNOT);
1782 #endif
1783 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1784 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1785 	    (m->m_pkthdr.csum_data != 0xffff)) {
1786 		/*
1787 		 * The checksum either did not have hardware offload
1788 		 * or it was a bad checksum. We can't LRO such
1789 		 * a packet.
1790 		 */
1791 		counter_u64_add(tcp_bad_csums, 1);
1792 		return (TCP_LRO_CANNOT);
1793 	}
1794 	/* We expect a contiguous header [eh, ip, tcp]. */
1795 	pa = tcp_lro_parser(m, &po, &pi, true);
1796 	if (__predict_false(pa == NULL))
1797 		return (TCP_LRO_NOT_SUPPORTED);
1798 
1799 	/* We don't expect any padding. */
1800 	error = tcp_lro_trim_mbuf_chain(m, pa);
1801 	if (__predict_false(error != 0))
1802 		return (error);
1803 
1804 #ifdef INET
1805 	switch (pa->data.lro_type) {
1806 	case LRO_TYPE_IPV4_TCP:
1807 		error = tcp_lro_rx_ipv4(lc, m, pa->ip4);
1808 		if (__predict_false(error != 0))
1809 			return (error);
1810 		break;
1811 	default:
1812 		break;
1813 	}
1814 #endif
1815 	/* If no hardware or arrival stamp on the packet add timestamp */
1816 	if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
1817 		m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
1818 		m->m_flags |= M_TSTMP_LRO;
1819 	}
1820 
1821 	/* Get pointer to TCP header. */
1822 	th = pa->tcp;
1823 
1824 	/* Don't process SYN packets. */
1825 	if (__predict_false(th->th_flags & TH_SYN))
1826 		return (TCP_LRO_CANNOT);
1827 
1828 	/* Get total TCP header length and compute payload length. */
1829 	tcp_opt_len = (th->th_off << 2);
1830 	tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th -
1831 	    (uint8_t *)m->m_data) - tcp_opt_len;
1832 	tcp_opt_len -= sizeof(*th);
1833 
1834 	/* Don't process invalid TCP headers. */
1835 	if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0))
1836 		return (TCP_LRO_CANNOT);
1837 
1838 	/* Compute TCP data only checksum. */
1839 	if (tcp_data_len == 0)
1840 		tcp_data_sum = 0;	/* no data, no checksum */
1841 	else if (__predict_false(csum != 0))
1842 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum);
1843 	else
1844 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum);
1845 
1846 	/* Save TCP info in mbuf. */
1847 	m->m_nextpkt = NULL;
1848 	m->m_pkthdr.rcvif = lc->ifp;
1849 	m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum;
1850 	m->m_pkthdr.lro_tcp_d_len = tcp_data_len;
1851 	m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data);
1852 	m->m_pkthdr.lro_nsegs = 1;
1853 
1854 	/* Get hash bucket. */
1855 	if (!use_hash) {
1856 		bucket = &lc->lro_hash[0];
1857 	} else {
1858 		bucket = tcp_lro_rx_get_bucket(lc, m, pa);
1859 	}
1860 
1861 	/* Try to find a matching previous segment. */
1862 	LIST_FOREACH(le, bucket, hash_next) {
1863 		/* Compare addresses and ports. */
1864 		if (lro_address_compare(&po.data, &le->outer.data) == false ||
1865 		    lro_address_compare(&pi.data, &le->inner.data) == false)
1866 			continue;
1867 
1868 		/* Check if no data and old ACK. */
1869 		if (tcp_data_len == 0 &&
1870 		    SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1871 			m_freem(m);
1872 			return (0);
1873 		}
1874 
1875 		/* Mark "m" in the last spot. */
1876 		le->m_last_mbuf->m_nextpkt = m;
1877 		/* Now set the tail to "m". */
1878 		le->m_last_mbuf = m;
1879 		return (0);
1880 	}
1881 
1882 	/* Try to find an empty slot. */
1883 	if (LIST_EMPTY(&lc->lro_free))
1884 		return (TCP_LRO_NO_ENTRIES);
1885 
1886 	/* Start a new segment chain. */
1887 	le = LIST_FIRST(&lc->lro_free);
1888 	LIST_REMOVE(le, next);
1889 	tcp_lro_active_insert(lc, bucket, le);
1890 
1891 	/* Make sure the headers are set. */
1892 	le->inner = pi;
1893 	le->outer = po;
1894 
1895 	/* Store time this entry was allocated. */
1896 	le->alloc_time = lc->lro_last_queue_time;
1897 
1898 	tcp_set_entry_to_mbuf(lc, le, m, th);
1899 
1900 	/* Now set the tail to "m". */
1901 	le->m_last_mbuf = m;
1902 
1903 	return (0);
1904 }
1905 
1906 int
1907 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
1908 {
1909 	int error;
1910 
1911 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1912 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1913 	    (m->m_pkthdr.csum_data != 0xffff)) {
1914 		/*
1915 		 * The checksum either did not have hardware offload
1916 		 * or it was a bad checksum. We can't LRO such
1917 		 * a packet.
1918 		 */
1919 		counter_u64_add(tcp_bad_csums, 1);
1920 		return (TCP_LRO_CANNOT);
1921 	}
1922 	/* get current time */
1923 	binuptime(&lc->lro_last_queue_time);
1924 	CURVNET_SET(lc->ifp->if_vnet);
1925 	error = tcp_lro_rx_common(lc, m, csum, true);
1926 	CURVNET_RESTORE();
1927 
1928 	return (error);
1929 }
1930 
1931 void
1932 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
1933 {
1934 	NET_EPOCH_ASSERT();
1935 	/* sanity checks */
1936 	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
1937 	    lc->lro_mbuf_max == 0)) {
1938 		/* packet drop */
1939 		m_freem(mb);
1940 		return;
1941 	}
1942 
1943 	/* check if packet is not LRO capable */
1944 	if (__predict_false((lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
1945 		/* input packet to network layer */
1946 		(*lc->ifp->if_input) (lc->ifp, mb);
1947 		return;
1948 	}
1949 
1950 	/* create sequence number */
1951 	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
1952 	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
1953 	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
1954 	    ((uint64_t)lc->lro_mbuf_count);
1955 
1956 	/* enter mbuf */
1957 	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
1958 
1959 	/* flush if array is full */
1960 	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
1961 		tcp_lro_flush_all(lc);
1962 }
1963 
1964 /* end */
1965