xref: /freebsd/sys/netinet/tcp_lro.c (revision bc5304a006238115291e7568583632889dffbab9)
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_flags & M_DECRYPTED))
399 			po->data.lro_flags |= LRO_FLAG_DECRYPTED;
400 	}
401 
402 	switch (po->data.lro_type) {
403 	case LRO_TYPE_IPV4_UDP:
404 	case LRO_TYPE_IPV6_UDP:
405 		/* Check for VXLAN headers. */
406 		if ((m->m_pkthdr.csum_flags & vxlan_csum) != vxlan_csum)
407 			break;
408 
409 		/* Try to parse inner headers. */
410 		data_ptr = tcp_lro_low_level_parser(data_ptr, pi, update_data, true,
411 						    (m->m_len - ((caddr_t)data_ptr - m->m_data)));
412 		if (data_ptr == NULL || (pi->total_hdr_len + po->total_hdr_len) > m->m_len)
413 			break;
414 
415 		/* Verify supported header types. */
416 		switch (pi->data.lro_type) {
417 		case LRO_TYPE_IPV4_TCP:
418 		case LRO_TYPE_IPV6_TCP:
419 			return (pi);
420 		default:
421 			break;
422 		}
423 		break;
424 	case LRO_TYPE_IPV4_TCP:
425 	case LRO_TYPE_IPV6_TCP:
426 		if (update_data)
427 			memset(pi, 0, sizeof(*pi));
428 		return (po);
429 	default:
430 		break;
431 	}
432 	return (NULL);
433 }
434 
435 static inline int
436 tcp_lro_trim_mbuf_chain(struct mbuf *m, const struct lro_parser *po)
437 {
438 	int len;
439 
440 	switch (po->data.lro_type) {
441 #ifdef INET
442 	case LRO_TYPE_IPV4_TCP:
443 		len = ((uint8_t *)po->ip4 - (uint8_t *)m->m_data) +
444 		    ntohs(po->ip4->ip_len);
445 		break;
446 #endif
447 #ifdef INET6
448 	case LRO_TYPE_IPV6_TCP:
449 		len = ((uint8_t *)po->ip6 - (uint8_t *)m->m_data) +
450 		    ntohs(po->ip6->ip6_plen) + sizeof(*po->ip6);
451 		break;
452 #endif
453 	default:
454 		return (TCP_LRO_CANNOT);
455 	}
456 
457 	/*
458 	 * If the frame is padded beyond the end of the IP packet,
459 	 * then trim the extra bytes off:
460 	 */
461 	if (__predict_true(m->m_pkthdr.len == len)) {
462 		return (0);
463 	} else if (m->m_pkthdr.len > len) {
464 		m_adj(m, len - m->m_pkthdr.len);
465 		return (0);
466 	}
467 	return (TCP_LRO_CANNOT);
468 }
469 
470 static struct tcphdr *
471 tcp_lro_get_th(struct mbuf *m)
472 {
473 	return ((struct tcphdr *)((uint8_t *)m->m_data + m->m_pkthdr.lro_tcp_h_off));
474 }
475 
476 static void
477 lro_free_mbuf_chain(struct mbuf *m)
478 {
479 	struct mbuf *save;
480 
481 	while (m) {
482 		save = m->m_nextpkt;
483 		m->m_nextpkt = NULL;
484 		m_freem(m);
485 		m = save;
486 	}
487 }
488 
489 void
490 tcp_lro_free(struct lro_ctrl *lc)
491 {
492 	struct lro_entry *le;
493 	unsigned x;
494 
495 	/* reset LRO free list */
496 	LIST_INIT(&lc->lro_free);
497 
498 	/* free active mbufs, if any */
499 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
500 		tcp_lro_active_remove(le);
501 		lro_free_mbuf_chain(le->m_head);
502 	}
503 
504 	/* free hash table */
505 	free(lc->lro_hash, M_LRO);
506 	lc->lro_hash = NULL;
507 	lc->lro_hashsz = 0;
508 
509 	/* free mbuf array, if any */
510 	for (x = 0; x != lc->lro_mbuf_count; x++)
511 		m_freem(lc->lro_mbuf_data[x].mb);
512 	lc->lro_mbuf_count = 0;
513 
514 	/* free allocated memory, if any */
515 	free(lc->lro_mbuf_data, M_LRO);
516 	lc->lro_mbuf_data = NULL;
517 }
518 
519 static uint16_t
520 tcp_lro_rx_csum_tcphdr(const struct tcphdr *th)
521 {
522 	const uint16_t *ptr;
523 	uint32_t csum;
524 	uint16_t len;
525 
526 	csum = -th->th_sum;	/* exclude checksum field */
527 	len = th->th_off;
528 	ptr = (const uint16_t *)th;
529 	while (len--) {
530 		csum += *ptr;
531 		ptr++;
532 		csum += *ptr;
533 		ptr++;
534 	}
535 	while (csum > 0xffff)
536 		csum = (csum >> 16) + (csum & 0xffff);
537 
538 	return (csum);
539 }
540 
541 static uint16_t
542 tcp_lro_rx_csum_data(const struct lro_parser *pa, uint16_t tcp_csum)
543 {
544 	uint32_t c;
545 	uint16_t cs;
546 
547 	c = tcp_csum;
548 
549 	switch (pa->data.lro_type) {
550 #ifdef INET6
551 	case LRO_TYPE_IPV6_TCP:
552 		/* Compute full pseudo IPv6 header checksum. */
553 		cs = in6_cksum_pseudo(pa->ip6, ntohs(pa->ip6->ip6_plen), pa->ip6->ip6_nxt, 0);
554 		break;
555 #endif
556 #ifdef INET
557 	case LRO_TYPE_IPV4_TCP:
558 		/* Compute full pseudo IPv4 header checsum. */
559 		cs = in_addword(ntohs(pa->ip4->ip_len) - sizeof(*pa->ip4), IPPROTO_TCP);
560 		cs = in_pseudo(pa->ip4->ip_src.s_addr, pa->ip4->ip_dst.s_addr, htons(cs));
561 		break;
562 #endif
563 	default:
564 		cs = 0;		/* Keep compiler happy. */
565 		break;
566 	}
567 
568 	/* Complement checksum. */
569 	cs = ~cs;
570 	c += cs;
571 
572 	/* Remove TCP header checksum. */
573 	cs = ~tcp_lro_rx_csum_tcphdr(pa->tcp);
574 	c += cs;
575 
576 	/* Compute checksum remainder. */
577 	while (c > 0xffff)
578 		c = (c >> 16) + (c & 0xffff);
579 
580 	return (c);
581 }
582 
583 static void
584 tcp_lro_rx_done(struct lro_ctrl *lc)
585 {
586 	struct lro_entry *le;
587 
588 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
589 		tcp_lro_active_remove(le);
590 		tcp_lro_flush(lc, le);
591 	}
592 }
593 
594 void
595 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
596 {
597 	struct lro_entry *le, *le_tmp;
598 	uint64_t now, tov;
599 	struct bintime bt;
600 
601 	if (LIST_EMPTY(&lc->lro_active))
602 		return;
603 
604 	/* get timeout time and current time in ns */
605 	binuptime(&bt);
606 	now = bintime2ns(&bt);
607 	tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000));
608 	LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
609 		if (now >= (bintime2ns(&le->alloc_time) + tov)) {
610 			tcp_lro_active_remove(le);
611 			tcp_lro_flush(lc, le);
612 		}
613 	}
614 }
615 
616 #ifdef INET
617 static int
618 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4)
619 {
620 	uint16_t csum;
621 
622 	/* Legacy IP has a header checksum that needs to be correct. */
623 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
624 		if (__predict_false((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0)) {
625 			lc->lro_bad_csum++;
626 			return (TCP_LRO_CANNOT);
627 		}
628 	} else {
629 		csum = in_cksum_hdr(ip4);
630 		if (__predict_false(csum != 0)) {
631 			lc->lro_bad_csum++;
632 			return (TCP_LRO_CANNOT);
633 		}
634 	}
635 	return (0);
636 }
637 #endif
638 
639 #ifdef TCPHPTS
640 static void
641 tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
642     const struct lro_entry *le, const struct mbuf *m,
643     int frm, int32_t tcp_data_len, uint32_t th_seq,
644     uint32_t th_ack, uint16_t th_win)
645 {
646 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
647 		union tcp_log_stackspecific log;
648 		struct timeval tv, btv;
649 		uint32_t cts;
650 
651 		cts = tcp_get_usecs(&tv);
652 		memset(&log, 0, sizeof(union tcp_log_stackspecific));
653 		log.u_bbr.flex8 = frm;
654 		log.u_bbr.flex1 = tcp_data_len;
655 		if (m)
656 			log.u_bbr.flex2 = m->m_pkthdr.len;
657 		else
658 			log.u_bbr.flex2 = 0;
659 		log.u_bbr.flex3 = le->m_head->m_pkthdr.lro_nsegs;
660 		log.u_bbr.flex4 = le->m_head->m_pkthdr.lro_tcp_d_len;
661 		if (le->m_head) {
662 			log.u_bbr.flex5 = le->m_head->m_pkthdr.len;
663 			log.u_bbr.delRate = le->m_head->m_flags;
664 			log.u_bbr.rttProp = le->m_head->m_pkthdr.rcv_tstmp;
665 		}
666 		log.u_bbr.inflight = th_seq;
667 		log.u_bbr.delivered = th_ack;
668 		log.u_bbr.timeStamp = cts;
669 		log.u_bbr.epoch = le->next_seq;
670 		log.u_bbr.lt_epoch = le->ack_seq;
671 		log.u_bbr.pacing_gain = th_win;
672 		log.u_bbr.cwnd_gain = le->window;
673 		log.u_bbr.lost = curcpu;
674 		log.u_bbr.cur_del_rate = (uintptr_t)m;
675 		log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
676 		bintime2timeval(&lc->lro_last_queue_time, &btv);
677 		log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
678 		log.u_bbr.flex7 = le->compressed;
679 		log.u_bbr.pacing_gain = le->uncompressed;
680 		if (in_epoch(net_epoch_preempt))
681 			log.u_bbr.inhpts = 1;
682 		else
683 			log.u_bbr.inhpts = 0;
684 		TCP_LOG_EVENTP(tp, NULL,
685 			       &tp->t_inpcb->inp_socket->so_rcv,
686 			       &tp->t_inpcb->inp_socket->so_snd,
687 			       TCP_LOG_LRO, 0,
688 			       0, &log, false, &tv);
689 	}
690 }
691 #endif
692 
693 static inline void
694 tcp_lro_assign_and_checksum_16(uint16_t *ptr, uint16_t value, uint16_t *psum)
695 {
696 	uint32_t csum;
697 
698 	csum = 0xffff - *ptr + value;
699 	while (csum > 0xffff)
700 		csum = (csum >> 16) + (csum & 0xffff);
701 	*ptr = value;
702 	*psum = csum;
703 }
704 
705 static uint16_t
706 tcp_lro_update_checksum(const struct lro_parser *pa, const struct lro_entry *le,
707     uint16_t payload_len, uint16_t delta_sum)
708 {
709 	uint32_t csum;
710 	uint16_t tlen;
711 	uint16_t temp[5] = {};
712 
713 	switch (pa->data.lro_type) {
714 	case LRO_TYPE_IPV4_TCP:
715 		/* Compute new IPv4 length. */
716 		tlen = (pa->ip4->ip_hl << 2) + (pa->tcp->th_off << 2) + payload_len;
717 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
718 
719 		/* Subtract delta from current IPv4 checksum. */
720 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
721 		while (csum > 0xffff)
722 			csum = (csum >> 16) + (csum & 0xffff);
723 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
724 		goto update_tcp_header;
725 
726 	case LRO_TYPE_IPV6_TCP:
727 		/* Compute new IPv6 length. */
728 		tlen = (pa->tcp->th_off << 2) + payload_len;
729 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
730 		goto update_tcp_header;
731 
732 	case LRO_TYPE_IPV4_UDP:
733 		/* Compute new IPv4 length. */
734 		tlen = (pa->ip4->ip_hl << 2) + sizeof(*pa->udp) + payload_len;
735 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
736 
737 		/* Subtract delta from current IPv4 checksum. */
738 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
739 		while (csum > 0xffff)
740 			csum = (csum >> 16) + (csum & 0xffff);
741 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
742 		goto update_udp_header;
743 
744 	case LRO_TYPE_IPV6_UDP:
745 		/* Compute new IPv6 length. */
746 		tlen = sizeof(*pa->udp) + payload_len;
747 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
748 		goto update_udp_header;
749 
750 	default:
751 		return (0);
752 	}
753 
754 update_tcp_header:
755 	/* Compute current TCP header checksum. */
756 	temp[2] = tcp_lro_rx_csum_tcphdr(pa->tcp);
757 
758 	/* Incorporate the latest ACK into the TCP header. */
759 	pa->tcp->th_ack = le->ack_seq;
760 	pa->tcp->th_win = le->window;
761 
762 	/* Incorporate latest timestamp into the TCP header. */
763 	if (le->timestamp != 0) {
764 		uint32_t *ts_ptr;
765 
766 		ts_ptr = (uint32_t *)(pa->tcp + 1);
767 		ts_ptr[1] = htonl(le->tsval);
768 		ts_ptr[2] = le->tsecr;
769 	}
770 
771 	/* Compute new TCP header checksum. */
772 	temp[3] = tcp_lro_rx_csum_tcphdr(pa->tcp);
773 
774 	/* Compute new TCP checksum. */
775 	csum = pa->tcp->th_sum + 0xffff - delta_sum +
776 	    0xffff - temp[0] + 0xffff - temp[3] + temp[2];
777 	while (csum > 0xffff)
778 		csum = (csum >> 16) + (csum & 0xffff);
779 
780 	/* Assign new TCP checksum. */
781 	tcp_lro_assign_and_checksum_16(&pa->tcp->th_sum, csum, &temp[4]);
782 
783 	/* Compute all modififications affecting next checksum. */
784 	csum = temp[0] + temp[1] + 0xffff - temp[2] +
785 	    temp[3] + temp[4] + delta_sum;
786 	while (csum > 0xffff)
787 		csum = (csum >> 16) + (csum & 0xffff);
788 
789 	/* Return delta checksum to next stage, if any. */
790 	return (csum);
791 
792 update_udp_header:
793 	tlen = sizeof(*pa->udp) + payload_len;
794 	/* Assign new UDP length and compute checksum delta. */
795 	tcp_lro_assign_and_checksum_16(&pa->udp->uh_ulen, htons(tlen), &temp[2]);
796 
797 	/* Check if there is a UDP checksum. */
798 	if (__predict_false(pa->udp->uh_sum != 0)) {
799 		/* Compute new UDP checksum. */
800 		csum = pa->udp->uh_sum + 0xffff - delta_sum +
801 		    0xffff - temp[0] + 0xffff - temp[2];
802 		while (csum > 0xffff)
803 			csum = (csum >> 16) + (csum & 0xffff);
804 		/* Assign new UDP checksum. */
805 		tcp_lro_assign_and_checksum_16(&pa->udp->uh_sum, csum, &temp[3]);
806 	}
807 
808 	/* Compute all modififications affecting next checksum. */
809 	csum = temp[0] + temp[1] + temp[2] + temp[3] + delta_sum;
810 	while (csum > 0xffff)
811 		csum = (csum >> 16) + (csum & 0xffff);
812 
813 	/* Return delta checksum to next stage, if any. */
814 	return (csum);
815 }
816 
817 static void
818 tcp_flush_out_entry(struct lro_ctrl *lc, struct lro_entry *le)
819 {
820 	/* Check if we need to recompute any checksums. */
821 	if (le->m_head->m_pkthdr.lro_nsegs > 1) {
822 		uint16_t csum;
823 
824 		switch (le->inner.data.lro_type) {
825 		case LRO_TYPE_IPV4_TCP:
826 			csum = tcp_lro_update_checksum(&le->inner, le,
827 			    le->m_head->m_pkthdr.lro_tcp_d_len,
828 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
829 			csum = tcp_lro_update_checksum(&le->outer, NULL,
830 			    le->m_head->m_pkthdr.lro_tcp_d_len +
831 			    le->inner.total_hdr_len, csum);
832 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
833 			    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
834 			le->m_head->m_pkthdr.csum_data = 0xffff;
835 			break;
836 		case LRO_TYPE_IPV6_TCP:
837 			csum = tcp_lro_update_checksum(&le->inner, le,
838 			    le->m_head->m_pkthdr.lro_tcp_d_len,
839 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
840 			csum = tcp_lro_update_checksum(&le->outer, NULL,
841 			    le->m_head->m_pkthdr.lro_tcp_d_len +
842 			    le->inner.total_hdr_len, csum);
843 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
844 			    CSUM_PSEUDO_HDR;
845 			le->m_head->m_pkthdr.csum_data = 0xffff;
846 			break;
847 		case LRO_TYPE_NONE:
848 			switch (le->outer.data.lro_type) {
849 			case LRO_TYPE_IPV4_TCP:
850 				csum = tcp_lro_update_checksum(&le->outer, le,
851 				    le->m_head->m_pkthdr.lro_tcp_d_len,
852 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
853 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
854 				    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
855 				le->m_head->m_pkthdr.csum_data = 0xffff;
856 				break;
857 			case LRO_TYPE_IPV6_TCP:
858 				csum = tcp_lro_update_checksum(&le->outer, le,
859 				    le->m_head->m_pkthdr.lro_tcp_d_len,
860 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
861 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
862 				    CSUM_PSEUDO_HDR;
863 				le->m_head->m_pkthdr.csum_data = 0xffff;
864 				break;
865 			default:
866 				break;
867 			}
868 			break;
869 		default:
870 			break;
871 		}
872 	}
873 
874 	/*
875 	 * Break any chain, this is not set to NULL on the singleton
876 	 * case m_nextpkt points to m_head. Other case set them
877 	 * m_nextpkt to NULL in push_and_replace.
878 	 */
879 	le->m_head->m_nextpkt = NULL;
880 	lc->lro_queued += le->m_head->m_pkthdr.lro_nsegs;
881 	(*lc->ifp->if_input)(lc->ifp, le->m_head);
882 }
883 
884 static void
885 tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le,
886     struct mbuf *m, struct tcphdr *th)
887 {
888 	uint32_t *ts_ptr;
889 	uint16_t tcp_data_len;
890 	uint16_t tcp_opt_len;
891 
892 	ts_ptr = (uint32_t *)(th + 1);
893 	tcp_opt_len = (th->th_off << 2);
894 	tcp_opt_len -= sizeof(*th);
895 
896 	/* Check if there is a timestamp option. */
897 	if (tcp_opt_len == 0 ||
898 	    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
899 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
900 		/* We failed to find the timestamp option. */
901 		le->timestamp = 0;
902 	} else {
903 		le->timestamp = 1;
904 		le->tsval = ntohl(*(ts_ptr + 1));
905 		le->tsecr = *(ts_ptr + 2);
906 	}
907 
908 	tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
909 
910 	/* Pull out TCP sequence numbers and window size. */
911 	le->next_seq = ntohl(th->th_seq) + tcp_data_len;
912 	le->ack_seq = th->th_ack;
913 	le->window = th->th_win;
914 
915 	/* Setup new data pointers. */
916 	le->m_head = m;
917 	le->m_tail = m_last(m);
918 }
919 
920 static void
921 tcp_push_and_replace(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m)
922 {
923 	struct lro_parser *pa;
924 
925 	/*
926 	 * Push up the stack of the current entry
927 	 * and replace it with "m".
928 	 */
929 	struct mbuf *msave;
930 
931 	/* Grab off the next and save it */
932 	msave = le->m_head->m_nextpkt;
933 	le->m_head->m_nextpkt = NULL;
934 
935 	/* Now push out the old entry */
936 	tcp_flush_out_entry(lc, le);
937 
938 	/* Re-parse new header, should not fail. */
939 	pa = tcp_lro_parser(m, &le->outer, &le->inner, false);
940 	KASSERT(pa != NULL,
941 	    ("tcp_push_and_replace: LRO parser failed on m=%p\n", m));
942 
943 	/*
944 	 * Now to replace the data properly in the entry
945 	 * we have to reset the TCP header and
946 	 * other fields.
947 	 */
948 	tcp_set_entry_to_mbuf(lc, le, m, pa->tcp);
949 
950 	/* Restore the next list */
951 	m->m_nextpkt = msave;
952 }
953 
954 static void
955 tcp_lro_mbuf_append_pkthdr(struct mbuf *m, const struct mbuf *p)
956 {
957 	uint32_t csum;
958 
959 	if (m->m_pkthdr.lro_nsegs == 1) {
960 		/* Compute relative checksum. */
961 		csum = p->m_pkthdr.lro_tcp_d_csum;
962 	} else {
963 		/* Merge TCP data checksums. */
964 		csum = (uint32_t)m->m_pkthdr.lro_tcp_d_csum +
965 		    (uint32_t)p->m_pkthdr.lro_tcp_d_csum;
966 		while (csum > 0xffff)
967 			csum = (csum >> 16) + (csum & 0xffff);
968 	}
969 
970 	/* Update various counters. */
971 	m->m_pkthdr.len += p->m_pkthdr.lro_tcp_d_len;
972 	m->m_pkthdr.lro_tcp_d_csum = csum;
973 	m->m_pkthdr.lro_tcp_d_len += p->m_pkthdr.lro_tcp_d_len;
974 	m->m_pkthdr.lro_nsegs += p->m_pkthdr.lro_nsegs;
975 }
976 
977 static void
978 tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le)
979 {
980 	/*
981 	 * Walk through the mbuf chain we
982 	 * have on tap and compress/condense
983 	 * as required.
984 	 */
985 	uint32_t *ts_ptr;
986 	struct mbuf *m;
987 	struct tcphdr *th;
988 	uint32_t tcp_data_len_total;
989 	uint32_t tcp_data_seg_total;
990 	uint16_t tcp_data_len;
991 	uint16_t tcp_opt_len;
992 
993 	/*
994 	 * First we must check the lead (m_head)
995 	 * we must make sure that it is *not*
996 	 * something that should be sent up
997 	 * right away (sack etc).
998 	 */
999 again:
1000 	m = le->m_head->m_nextpkt;
1001 	if (m == NULL) {
1002 		/* Just one left. */
1003 		return;
1004 	}
1005 
1006 	th = tcp_lro_get_th(m);
1007 	tcp_opt_len = (th->th_off << 2);
1008 	tcp_opt_len -= sizeof(*th);
1009 	ts_ptr = (uint32_t *)(th + 1);
1010 
1011 	if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1012 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
1013 		/*
1014 		 * Its not the timestamp. We can't
1015 		 * use this guy as the head.
1016 		 */
1017 		le->m_head->m_nextpkt = m->m_nextpkt;
1018 		tcp_push_and_replace(lc, le, m);
1019 		goto again;
1020 	}
1021 	if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
1022 		/*
1023 		 * Make sure that previously seen segements/ACKs are delivered
1024 		 * before this segment, e.g. FIN.
1025 		 */
1026 		le->m_head->m_nextpkt = m->m_nextpkt;
1027 		tcp_push_and_replace(lc, le, m);
1028 		goto again;
1029 	}
1030 	while((m = le->m_head->m_nextpkt) != NULL) {
1031 		/*
1032 		 * condense m into le, first
1033 		 * pull m out of the list.
1034 		 */
1035 		le->m_head->m_nextpkt = m->m_nextpkt;
1036 		m->m_nextpkt = NULL;
1037 		/* Setup my data */
1038 		tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
1039 		th = tcp_lro_get_th(m);
1040 		ts_ptr = (uint32_t *)(th + 1);
1041 		tcp_opt_len = (th->th_off << 2);
1042 		tcp_opt_len -= sizeof(*th);
1043 		tcp_data_len_total = le->m_head->m_pkthdr.lro_tcp_d_len + tcp_data_len;
1044 		tcp_data_seg_total = le->m_head->m_pkthdr.lro_nsegs + m->m_pkthdr.lro_nsegs;
1045 
1046 		if (tcp_data_seg_total >= lc->lro_ackcnt_lim ||
1047 		    tcp_data_len_total >= lc->lro_length_lim) {
1048 			/* Flush now if appending will result in overflow. */
1049 			tcp_push_and_replace(lc, le, m);
1050 			goto again;
1051 		}
1052 		if (tcp_opt_len != 0 &&
1053 		    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1054 		    *ts_ptr != TCP_LRO_TS_OPTION)) {
1055 			/*
1056 			 * Maybe a sack in the new one? We need to
1057 			 * start all over after flushing the
1058 			 * current le. We will go up to the beginning
1059 			 * and flush it (calling the replace again possibly
1060 			 * or just returning).
1061 			 */
1062 			tcp_push_and_replace(lc, le, m);
1063 			goto again;
1064 		}
1065 		if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
1066 			tcp_push_and_replace(lc, le, m);
1067 			goto again;
1068 		}
1069 		if (tcp_opt_len != 0) {
1070 			uint32_t tsval = ntohl(*(ts_ptr + 1));
1071 			/* Make sure timestamp values are increasing. */
1072 			if (TSTMP_GT(le->tsval, tsval))  {
1073 				tcp_push_and_replace(lc, le, m);
1074 				goto again;
1075 			}
1076 			le->tsval = tsval;
1077 			le->tsecr = *(ts_ptr + 2);
1078 		}
1079 		/* Try to append the new segment. */
1080 		if (__predict_false(ntohl(th->th_seq) != le->next_seq ||
1081 				    (tcp_data_len == 0 &&
1082 				     le->ack_seq == th->th_ack &&
1083 				     le->window == th->th_win))) {
1084 			/* Out of order packet or duplicate ACK. */
1085 			tcp_push_and_replace(lc, le, m);
1086 			goto again;
1087 		}
1088 		if (tcp_data_len != 0 ||
1089 		    SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1090 			le->next_seq += tcp_data_len;
1091 			le->ack_seq = th->th_ack;
1092 			le->window = th->th_win;
1093 		} else if (th->th_ack == le->ack_seq) {
1094 			le->window = WIN_MAX(le->window, th->th_win);
1095 		}
1096 
1097 		if (tcp_data_len == 0) {
1098 			m_freem(m);
1099 			continue;
1100 		}
1101 
1102 		/* Merge TCP data checksum and length to head mbuf. */
1103 		tcp_lro_mbuf_append_pkthdr(le->m_head, m);
1104 
1105 		/*
1106 		 * Adjust the mbuf so that m_data points to the first byte of
1107 		 * the ULP payload.  Adjust the mbuf to avoid complications and
1108 		 * append new segment to existing mbuf chain.
1109 		 */
1110 		m_adj(m, m->m_pkthdr.len - tcp_data_len);
1111 		m_demote_pkthdr(m);
1112 		le->m_tail->m_next = m;
1113 		le->m_tail = m_last(m);
1114 	}
1115 }
1116 
1117 #ifdef TCPHPTS
1118 static void
1119 tcp_queue_pkts(struct inpcb *inp, struct tcpcb *tp, struct lro_entry *le)
1120 {
1121 	INP_WLOCK_ASSERT(inp);
1122 	if (tp->t_in_pkt == NULL) {
1123 		/* Nothing yet there */
1124 		tp->t_in_pkt = le->m_head;
1125 		tp->t_tail_pkt = le->m_last_mbuf;
1126 	} else {
1127 		/* Already some there */
1128 		tp->t_tail_pkt->m_nextpkt = le->m_head;
1129 		tp->t_tail_pkt = le->m_last_mbuf;
1130 	}
1131 	le->m_head = NULL;
1132 	le->m_last_mbuf = NULL;
1133 }
1134 
1135 static struct mbuf *
1136 tcp_lro_get_last_if_ackcmp(struct lro_ctrl *lc, struct lro_entry *le,
1137     struct inpcb *inp, int32_t *new_m)
1138 {
1139 	struct tcpcb *tp;
1140 	struct mbuf *m;
1141 
1142 	tp = intotcpcb(inp);
1143 	if (__predict_false(tp == NULL))
1144 		return (NULL);
1145 
1146 	/* Look at the last mbuf if any in queue */
1147 	m = tp->t_tail_pkt;
1148 	if (m != NULL && (m->m_flags & M_ACKCMP) != 0) {
1149 		if (M_TRAILINGSPACE(m) >= sizeof(struct tcp_ackent)) {
1150 			tcp_lro_log(tp, lc, le, NULL, 23, 0, 0, 0, 0);
1151 			*new_m = 0;
1152 			counter_u64_add(tcp_extra_mbuf, 1);
1153 			return (m);
1154 		} else {
1155 			/* Mark we ran out of space */
1156 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1157 		}
1158 	}
1159 	/* Decide mbuf size. */
1160 	if (inp->inp_flags2 & INP_MBUF_L_ACKS)
1161 		m = m_getcl(M_NOWAIT, MT_DATA, M_ACKCMP | M_PKTHDR);
1162 	else
1163 		m = m_gethdr(M_NOWAIT, MT_DATA);
1164 
1165 	if (__predict_false(m == NULL)) {
1166 		counter_u64_add(tcp_would_have_but, 1);
1167 		return (NULL);
1168 	}
1169 	counter_u64_add(tcp_comp_total, 1);
1170 	m->m_flags |= M_ACKCMP;
1171 	*new_m = 1;
1172 	return (m);
1173 }
1174 
1175 static struct inpcb *
1176 tcp_lro_lookup(struct ifnet *ifp, struct lro_parser *pa)
1177 {
1178 	struct inpcb *inp;
1179 
1180 	NET_EPOCH_ASSERT();
1181 
1182 	switch (pa->data.lro_type) {
1183 #ifdef INET6
1184 	case LRO_TYPE_IPV6_TCP:
1185 		inp = in6_pcblookup(&V_tcbinfo,
1186 		    &pa->data.s_addr.v6,
1187 		    pa->data.s_port,
1188 		    &pa->data.d_addr.v6,
1189 		    pa->data.d_port,
1190 		    INPLOOKUP_WLOCKPCB,
1191 		    ifp);
1192 		break;
1193 #endif
1194 #ifdef INET
1195 	case LRO_TYPE_IPV4_TCP:
1196 		inp = in_pcblookup(&V_tcbinfo,
1197 		    pa->data.s_addr.v4,
1198 		    pa->data.s_port,
1199 		    pa->data.d_addr.v4,
1200 		    pa->data.d_port,
1201 		    INPLOOKUP_WLOCKPCB,
1202 		    ifp);
1203 		break;
1204 #endif
1205 	default:
1206 		inp = NULL;
1207 		break;
1208 	}
1209 	return (inp);
1210 }
1211 
1212 static inline bool
1213 tcp_lro_ack_valid(struct mbuf *m, struct tcphdr *th, uint32_t **ppts, bool *other_opts)
1214 {
1215 	/*
1216 	 * This function returns two bits of valuable information.
1217 	 * a) Is what is present capable of being ack-compressed,
1218 	 *    we can ack-compress if there is no options or just
1219 	 *    a timestamp option, and of course the th_flags must
1220 	 *    be correct as well.
1221 	 * b) Our other options present such as SACK. This is
1222 	 *    used to determine if we want to wakeup or not.
1223 	 */
1224 	bool ret = true;
1225 
1226 	switch (th->th_off << 2) {
1227 	case (sizeof(*th) + TCPOLEN_TSTAMP_APPA):
1228 		*ppts = (uint32_t *)(th + 1);
1229 		/* Check if we have only one timestamp option. */
1230 		if (**ppts == TCP_LRO_TS_OPTION)
1231 			*other_opts = false;
1232 		else {
1233 			*other_opts = true;
1234 			ret = false;
1235 		}
1236 		break;
1237 	case (sizeof(*th)):
1238 		/* No options. */
1239 		*ppts = NULL;
1240 		*other_opts = false;
1241 		break;
1242 	default:
1243 		*ppts = NULL;
1244 		*other_opts = true;
1245 		ret = false;
1246 		break;
1247 	}
1248 	/* For ACKCMP we only accept ACK, PUSH, ECE and CWR. */
1249 	if ((th->th_flags & ~(TH_ACK | TH_PUSH | TH_ECE | TH_CWR)) != 0)
1250 		ret = false;
1251 	/* If it has data on it we cannot compress it */
1252 	if (m->m_pkthdr.lro_tcp_d_len)
1253 		ret = false;
1254 
1255 	/* ACK flag must be set. */
1256 	if (!(th->th_flags & TH_ACK))
1257 		ret = false;
1258 	return (ret);
1259 }
1260 
1261 static int
1262 tcp_lro_flush_tcphpts(struct lro_ctrl *lc, struct lro_entry *le)
1263 {
1264 	struct inpcb *inp;
1265 	struct tcpcb *tp;
1266 	struct mbuf **pp, *cmp, *mv_to;
1267 	bool bpf_req, should_wake;
1268 
1269 	/* Check if packet doesn't belongs to our network interface. */
1270 	if ((tcplro_stacks_wanting_mbufq == 0) ||
1271 	    (le->outer.data.vlan_id != 0) ||
1272 	    (le->inner.data.lro_type != LRO_TYPE_NONE))
1273 		return (TCP_LRO_CANNOT);
1274 
1275 #ifdef INET6
1276 	/*
1277 	 * Be proactive about unspecified IPv6 address in source. As
1278 	 * we use all-zero to indicate unbounded/unconnected pcb,
1279 	 * unspecified IPv6 address can be used to confuse us.
1280 	 *
1281 	 * Note that packets with unspecified IPv6 destination is
1282 	 * already dropped in ip6_input.
1283 	 */
1284 	if (__predict_false(le->outer.data.lro_type == LRO_TYPE_IPV6_TCP &&
1285 	    IN6_IS_ADDR_UNSPECIFIED(&le->outer.data.s_addr.v6)))
1286 		return (TCP_LRO_CANNOT);
1287 
1288 	if (__predict_false(le->inner.data.lro_type == LRO_TYPE_IPV6_TCP &&
1289 	    IN6_IS_ADDR_UNSPECIFIED(&le->inner.data.s_addr.v6)))
1290 		return (TCP_LRO_CANNOT);
1291 #endif
1292 	/* Lookup inp, if any. */
1293 	inp = tcp_lro_lookup(lc->ifp,
1294 	    (le->inner.data.lro_type == LRO_TYPE_NONE) ? &le->outer : &le->inner);
1295 	if (inp == NULL)
1296 		return (TCP_LRO_CANNOT);
1297 
1298 	counter_u64_add(tcp_inp_lro_locks_taken, 1);
1299 
1300 	/* Get TCP control structure. */
1301 	tp = intotcpcb(inp);
1302 
1303 	/* Check if the inp is dead, Jim. */
1304 	if (tp == NULL ||
1305 	    (inp->inp_flags & (INP_DROPPED | INP_TIMEWAIT)) ||
1306 	    (inp->inp_flags2 & INP_FREED)) {
1307 		INP_WUNLOCK(inp);
1308 		return (TCP_LRO_CANNOT);
1309 	}
1310 	if ((inp->inp_irq_cpu_set == 0)  && (lc->lro_cpu_is_set == 1)) {
1311 		inp->inp_irq_cpu = lc->lro_last_cpu;
1312 		inp->inp_irq_cpu_set = 1;
1313 	}
1314 	/* Check if the transport doesn't support the needed optimizations. */
1315 	if ((inp->inp_flags2 & (INP_SUPPORTS_MBUFQ | INP_MBUF_ACKCMP)) == 0) {
1316 		INP_WUNLOCK(inp);
1317 		return (TCP_LRO_CANNOT);
1318 	}
1319 
1320 	if (inp->inp_flags2 & INP_MBUF_QUEUE_READY)
1321 		should_wake = false;
1322 	else
1323 		should_wake = true;
1324 	/* Check if packets should be tapped to BPF. */
1325 	bpf_req = bpf_peers_present(lc->ifp->if_bpf);
1326 
1327 	/* Strip and compress all the incoming packets. */
1328 	cmp = NULL;
1329 	for (pp = &le->m_head; *pp != NULL; ) {
1330 		mv_to = NULL;
1331 		if (do_bpf_strip_and_compress(inp, lc, le, pp,
1332 			 &cmp, &mv_to, &should_wake, bpf_req ) == false) {
1333 			/* Advance to next mbuf. */
1334 			pp = &(*pp)->m_nextpkt;
1335 		} else if (mv_to != NULL) {
1336 			/* We are asked to move pp up */
1337 			pp = &mv_to->m_nextpkt;
1338 		}
1339 	}
1340 	/* Update "m_last_mbuf", if any. */
1341 	if (pp == &le->m_head)
1342 		le->m_last_mbuf = *pp;
1343 	else
1344 		le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
1345 
1346 	/* Check if any data mbufs left. */
1347 	if (le->m_head != NULL) {
1348 		counter_u64_add(tcp_inp_lro_direct_queue, 1);
1349 		tcp_lro_log(tp, lc, le, NULL, 22, 1,
1350 			    inp->inp_flags2, inp->inp_in_input, 1);
1351 		tcp_queue_pkts(inp, tp, le);
1352 	}
1353 	if (should_wake) {
1354 		/* Wakeup */
1355 		counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
1356 		if ((*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0))
1357 			inp = NULL;
1358 	}
1359 	if (inp != NULL)
1360 		INP_WUNLOCK(inp);
1361 	return (0);	/* Success. */
1362 }
1363 #endif
1364 
1365 void
1366 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
1367 {
1368 	/* Only optimise if there are multiple packets waiting. */
1369 #ifdef TCPHPTS
1370 	int error;
1371 
1372 	CURVNET_SET(lc->ifp->if_vnet);
1373 	error = tcp_lro_flush_tcphpts(lc, le);
1374 	CURVNET_RESTORE();
1375 	if (error != 0) {
1376 #endif
1377 		tcp_lro_condense(lc, le);
1378 		tcp_flush_out_entry(lc, le);
1379 #ifdef TCPHPTS
1380 	}
1381 #endif
1382 	lc->lro_flushed++;
1383 	bzero(le, sizeof(*le));
1384 	LIST_INSERT_HEAD(&lc->lro_free, le, next);
1385 }
1386 
1387 #ifdef HAVE_INLINE_FLSLL
1388 #define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
1389 #else
1390 static inline uint64_t
1391 tcp_lro_msb_64(uint64_t x)
1392 {
1393 	x |= (x >> 1);
1394 	x |= (x >> 2);
1395 	x |= (x >> 4);
1396 	x |= (x >> 8);
1397 	x |= (x >> 16);
1398 	x |= (x >> 32);
1399 	return (x & ~(x >> 1));
1400 }
1401 #endif
1402 
1403 /*
1404  * The tcp_lro_sort() routine is comparable to qsort(), except it has
1405  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
1406  * number of elements to sort and 64 is the number of sequence bits
1407  * available. The algorithm is bit-slicing the 64-bit sequence number,
1408  * sorting one bit at a time from the most significant bit until the
1409  * least significant one, skipping the constant bits. This is
1410  * typically called a radix sort.
1411  */
1412 static void
1413 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
1414 {
1415 	struct lro_mbuf_sort temp;
1416 	uint64_t ones;
1417 	uint64_t zeros;
1418 	uint32_t x;
1419 	uint32_t y;
1420 
1421 repeat:
1422 	/* for small arrays insertion sort is faster */
1423 	if (size <= 12) {
1424 		for (x = 1; x < size; x++) {
1425 			temp = parray[x];
1426 			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
1427 				parray[y] = parray[y - 1];
1428 			parray[y] = temp;
1429 		}
1430 		return;
1431 	}
1432 
1433 	/* compute sequence bits which are constant */
1434 	ones = 0;
1435 	zeros = 0;
1436 	for (x = 0; x != size; x++) {
1437 		ones |= parray[x].seq;
1438 		zeros |= ~parray[x].seq;
1439 	}
1440 
1441 	/* compute bits which are not constant into "ones" */
1442 	ones &= zeros;
1443 	if (ones == 0)
1444 		return;
1445 
1446 	/* pick the most significant bit which is not constant */
1447 	ones = tcp_lro_msb_64(ones);
1448 
1449 	/*
1450 	 * Move entries having cleared sequence bits to the beginning
1451 	 * of the array:
1452 	 */
1453 	for (x = y = 0; y != size; y++) {
1454 		/* skip set bits */
1455 		if (parray[y].seq & ones)
1456 			continue;
1457 		/* swap entries */
1458 		temp = parray[x];
1459 		parray[x] = parray[y];
1460 		parray[y] = temp;
1461 		x++;
1462 	}
1463 
1464 	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
1465 
1466 	/* sort zeros */
1467 	tcp_lro_sort(parray, x);
1468 
1469 	/* sort ones */
1470 	parray += x;
1471 	size -= x;
1472 	goto repeat;
1473 }
1474 
1475 void
1476 tcp_lro_flush_all(struct lro_ctrl *lc)
1477 {
1478 	uint64_t seq;
1479 	uint64_t nseq;
1480 	unsigned x;
1481 
1482 	/* check if no mbufs to flush */
1483 	if (lc->lro_mbuf_count == 0)
1484 		goto done;
1485 	if (lc->lro_cpu_is_set == 0) {
1486 		if (lc->lro_last_cpu == curcpu) {
1487 			lc->lro_cnt_of_same_cpu++;
1488 			/* Have we reached the threshold to declare a cpu? */
1489 			if (lc->lro_cnt_of_same_cpu > tcp_lro_cpu_set_thresh)
1490 				lc->lro_cpu_is_set = 1;
1491 		} else {
1492 			lc->lro_last_cpu = curcpu;
1493 			lc->lro_cnt_of_same_cpu = 0;
1494 		}
1495 	}
1496 	CURVNET_SET(lc->ifp->if_vnet);
1497 
1498 	/* get current time */
1499 	binuptime(&lc->lro_last_queue_time);
1500 
1501 	/* sort all mbufs according to stream */
1502 	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
1503 
1504 	/* input data into LRO engine, stream by stream */
1505 	seq = 0;
1506 	for (x = 0; x != lc->lro_mbuf_count; x++) {
1507 		struct mbuf *mb;
1508 
1509 		/* get mbuf */
1510 		mb = lc->lro_mbuf_data[x].mb;
1511 
1512 		/* get sequence number, masking away the packet index */
1513 		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
1514 
1515 		/* check for new stream */
1516 		if (seq != nseq) {
1517 			seq = nseq;
1518 
1519 			/* flush active streams */
1520 			tcp_lro_rx_done(lc);
1521 		}
1522 
1523 		/* add packet to LRO engine */
1524 		if (tcp_lro_rx_common(lc, mb, 0, false) != 0) {
1525 			/* input packet to network layer */
1526 			(*lc->ifp->if_input)(lc->ifp, mb);
1527 			lc->lro_queued++;
1528 			lc->lro_flushed++;
1529 		}
1530 	}
1531 	CURVNET_RESTORE();
1532 done:
1533 	/* flush active streams */
1534 	tcp_lro_rx_done(lc);
1535 
1536 #ifdef TCPHPTS
1537 	tcp_run_hpts();
1538 #endif
1539 	lc->lro_mbuf_count = 0;
1540 }
1541 
1542 #ifdef TCPHPTS
1543 static void
1544 build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
1545     uint32_t *ts_ptr, uint16_t iptos)
1546 {
1547 	/*
1548 	 * Given a TCP ACK, summarize it down into the small TCP ACK
1549 	 * entry.
1550 	 */
1551 	ae->timestamp = m->m_pkthdr.rcv_tstmp;
1552 	if (m->m_flags & M_TSTMP_LRO)
1553 		ae->flags = TSTMP_LRO;
1554 	else if (m->m_flags & M_TSTMP)
1555 		ae->flags = TSTMP_HDWR;
1556 	ae->seq = ntohl(th->th_seq);
1557 	ae->ack = ntohl(th->th_ack);
1558 	ae->flags |= th->th_flags;
1559 	if (ts_ptr != NULL) {
1560 		ae->ts_value = ntohl(ts_ptr[1]);
1561 		ae->ts_echo = ntohl(ts_ptr[2]);
1562 		ae->flags |= HAS_TSTMP;
1563 	}
1564 	ae->win = ntohs(th->th_win);
1565 	ae->codepoint = iptos;
1566 }
1567 
1568 /*
1569  * Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
1570  * and strip all, but the IPv4/IPv6 header.
1571  */
1572 static bool
1573 do_bpf_strip_and_compress(struct inpcb *inp, struct lro_ctrl *lc,
1574     struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp, struct mbuf **mv_to,
1575     bool *should_wake, bool bpf_req)
1576 {
1577 	union {
1578 		void *ptr;
1579 		struct ip *ip4;
1580 		struct ip6_hdr *ip6;
1581 	} l3;
1582 	struct mbuf *m;
1583 	struct mbuf *nm;
1584 	struct tcphdr *th;
1585 	struct tcp_ackent *ack_ent;
1586 	uint32_t *ts_ptr;
1587 	int32_t n_mbuf;
1588 	bool other_opts, can_compress;
1589 	uint8_t lro_type;
1590 	uint16_t iptos;
1591 	int tcp_hdr_offset;
1592 	int idx;
1593 
1594 	/* Get current mbuf. */
1595 	m = *pp;
1596 
1597 	/* Let the BPF see the packet */
1598 	if (__predict_false(bpf_req))
1599 		ETHER_BPF_MTAP(lc->ifp, m);
1600 
1601 	tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
1602 	lro_type = le->inner.data.lro_type;
1603 	switch (lro_type) {
1604 	case LRO_TYPE_NONE:
1605 		lro_type = le->outer.data.lro_type;
1606 		switch (lro_type) {
1607 		case LRO_TYPE_IPV4_TCP:
1608 			tcp_hdr_offset -= sizeof(*le->outer.ip4);
1609 			m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1610 			break;
1611 		case LRO_TYPE_IPV6_TCP:
1612 			tcp_hdr_offset -= sizeof(*le->outer.ip6);
1613 			m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1614 			break;
1615 		default:
1616 			goto compressed;
1617 		}
1618 		break;
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 
1631 	MPASS(tcp_hdr_offset >= 0);
1632 
1633 	m_adj(m, tcp_hdr_offset);
1634 	m->m_flags |= M_LRO_EHDRSTRP;
1635 	m->m_flags &= ~M_ACKCMP;
1636 	m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
1637 
1638 	th = tcp_lro_get_th(m);
1639 
1640 	th->th_sum = 0;		/* TCP checksum is valid. */
1641 
1642 	/* Check if ACK can be compressed */
1643 	can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
1644 
1645 	/* Now lets look at the should wake states */
1646 	if ((other_opts == true) &&
1647 	    ((inp->inp_flags2 & INP_DONT_SACK_QUEUE) == 0)) {
1648 		/*
1649 		 * If there are other options (SACK?) and the
1650 		 * tcp endpoint has not expressly told us it does
1651 		 * not care about SACKS, then we should wake up.
1652 		 */
1653 		*should_wake = true;
1654 	}
1655 	/* Is the ack compressable? */
1656 	if (can_compress == false)
1657 		goto done;
1658 	/* Does the TCP endpoint support ACK compression? */
1659 	if ((inp->inp_flags2 & INP_MBUF_ACKCMP) == 0)
1660 		goto done;
1661 
1662 	/* Lets get the TOS/traffic class field */
1663 	l3.ptr = mtod(m, void *);
1664 	switch (lro_type) {
1665 	case LRO_TYPE_IPV4_TCP:
1666 		iptos = l3.ip4->ip_tos;
1667 		break;
1668 	case LRO_TYPE_IPV6_TCP:
1669 		iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
1670 		break;
1671 	default:
1672 		iptos = 0;	/* Keep compiler happy. */
1673 		break;
1674 	}
1675 	/* Now lets get space if we don't have some already */
1676 	if (*cmp == NULL) {
1677 new_one:
1678 		nm = tcp_lro_get_last_if_ackcmp(lc, le, inp, &n_mbuf);
1679 		if (__predict_false(nm == NULL))
1680 			goto done;
1681 		*cmp = nm;
1682 		if (n_mbuf) {
1683 			/*
1684 			 *  Link in the new cmp ack to our in-order place,
1685 			 * first set our cmp ack's next to where we are.
1686 			 */
1687 			nm->m_nextpkt = m;
1688 			(*pp) = nm;
1689 			/*
1690 			 * Set it up so mv_to is advanced to our
1691 			 * compressed ack. This way the caller can
1692 			 * advance pp to the right place.
1693 			 */
1694 			*mv_to = nm;
1695 			/*
1696 			 * Advance it here locally as well.
1697 			 */
1698 			pp = &nm->m_nextpkt;
1699 		}
1700 	} else {
1701 		/* We have one already we are working on */
1702 		nm = *cmp;
1703 		if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
1704 			/* We ran out of space */
1705 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1706 			goto new_one;
1707 		}
1708 	}
1709 	MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
1710 	counter_u64_add(tcp_inp_lro_compressed, 1);
1711 	le->compressed++;
1712 	/* We can add in to the one on the tail */
1713 	ack_ent = mtod(nm, struct tcp_ackent *);
1714 	idx = (nm->m_len / sizeof(struct tcp_ackent));
1715 	build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
1716 
1717 	/* Bump the size of both pkt-hdr and len */
1718 	nm->m_len += sizeof(struct tcp_ackent);
1719 	nm->m_pkthdr.len += sizeof(struct tcp_ackent);
1720 compressed:
1721 	/* Advance to next mbuf before freeing. */
1722 	*pp = m->m_nextpkt;
1723 	m->m_nextpkt = NULL;
1724 	m_freem(m);
1725 	return (true);
1726 done:
1727 	counter_u64_add(tcp_uncomp_total, 1);
1728 	le->uncompressed++;
1729 	return (false);
1730 }
1731 #endif
1732 
1733 static struct lro_head *
1734 tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser)
1735 {
1736 	u_long hash;
1737 
1738 	if (M_HASHTYPE_ISHASH(m)) {
1739 		hash = m->m_pkthdr.flowid;
1740 	} else {
1741 		for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++)
1742 			hash += parser->data.raw[i];
1743 	}
1744 	return (&lc->lro_hash[hash % lc->lro_hashsz]);
1745 }
1746 
1747 static int
1748 tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash)
1749 {
1750 	struct lro_parser pi;	/* inner address data */
1751 	struct lro_parser po;	/* outer address data */
1752 	struct lro_parser *pa;	/* current parser for TCP stream */
1753 	struct lro_entry *le;
1754 	struct lro_head *bucket;
1755 	struct tcphdr *th;
1756 	int tcp_data_len;
1757 	int tcp_opt_len;
1758 	int error;
1759 	uint16_t tcp_data_sum;
1760 
1761 #ifdef INET
1762 	/* Quickly decide if packet cannot be LRO'ed */
1763 	if (__predict_false(V_ipforwarding != 0))
1764 		return (TCP_LRO_CANNOT);
1765 #endif
1766 #ifdef INET6
1767 	/* Quickly decide if packet cannot be LRO'ed */
1768 	if (__predict_false(V_ip6_forwarding != 0))
1769 		return (TCP_LRO_CANNOT);
1770 #endif
1771 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1772 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1773 	    (m->m_pkthdr.csum_data != 0xffff)) {
1774 		/*
1775 		 * The checksum either did not have hardware offload
1776 		 * or it was a bad checksum. We can't LRO such
1777 		 * a packet.
1778 		 */
1779 		counter_u64_add(tcp_bad_csums, 1);
1780 		return (TCP_LRO_CANNOT);
1781 	}
1782 	/* We expect a contiguous header [eh, ip, tcp]. */
1783 	pa = tcp_lro_parser(m, &po, &pi, true);
1784 	if (__predict_false(pa == NULL))
1785 		return (TCP_LRO_NOT_SUPPORTED);
1786 
1787 	/* We don't expect any padding. */
1788 	error = tcp_lro_trim_mbuf_chain(m, pa);
1789 	if (__predict_false(error != 0))
1790 		return (error);
1791 
1792 #ifdef INET
1793 	switch (pa->data.lro_type) {
1794 	case LRO_TYPE_IPV4_TCP:
1795 		error = tcp_lro_rx_ipv4(lc, m, pa->ip4);
1796 		if (__predict_false(error != 0))
1797 			return (error);
1798 		break;
1799 	default:
1800 		break;
1801 	}
1802 #endif
1803 	/* If no hardware or arrival stamp on the packet add timestamp */
1804 	if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
1805 		m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
1806 		m->m_flags |= M_TSTMP_LRO;
1807 	}
1808 
1809 	/* Get pointer to TCP header. */
1810 	th = pa->tcp;
1811 
1812 	/* Don't process SYN packets. */
1813 	if (__predict_false(th->th_flags & TH_SYN))
1814 		return (TCP_LRO_CANNOT);
1815 
1816 	/* Get total TCP header length and compute payload length. */
1817 	tcp_opt_len = (th->th_off << 2);
1818 	tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th -
1819 	    (uint8_t *)m->m_data) - tcp_opt_len;
1820 	tcp_opt_len -= sizeof(*th);
1821 
1822 	/* Don't process invalid TCP headers. */
1823 	if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0))
1824 		return (TCP_LRO_CANNOT);
1825 
1826 	/* Compute TCP data only checksum. */
1827 	if (tcp_data_len == 0)
1828 		tcp_data_sum = 0;	/* no data, no checksum */
1829 	else if (__predict_false(csum != 0))
1830 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum);
1831 	else
1832 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum);
1833 
1834 	/* Save TCP info in mbuf. */
1835 	m->m_nextpkt = NULL;
1836 	m->m_pkthdr.rcvif = lc->ifp;
1837 	m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum;
1838 	m->m_pkthdr.lro_tcp_d_len = tcp_data_len;
1839 	m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data);
1840 	m->m_pkthdr.lro_nsegs = 1;
1841 
1842 	/* Get hash bucket. */
1843 	if (!use_hash) {
1844 		bucket = &lc->lro_hash[0];
1845 	} else {
1846 		bucket = tcp_lro_rx_get_bucket(lc, m, pa);
1847 	}
1848 
1849 	/* Try to find a matching previous segment. */
1850 	LIST_FOREACH(le, bucket, hash_next) {
1851 		/* Compare addresses and ports. */
1852 		if (lro_address_compare(&po.data, &le->outer.data) == false ||
1853 		    lro_address_compare(&pi.data, &le->inner.data) == false)
1854 			continue;
1855 
1856 		/* Check if no data and old ACK. */
1857 		if (tcp_data_len == 0 &&
1858 		    SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1859 			m_freem(m);
1860 			return (0);
1861 		}
1862 
1863 		/* Mark "m" in the last spot. */
1864 		le->m_last_mbuf->m_nextpkt = m;
1865 		/* Now set the tail to "m". */
1866 		le->m_last_mbuf = m;
1867 		return (0);
1868 	}
1869 
1870 	/* Try to find an empty slot. */
1871 	if (LIST_EMPTY(&lc->lro_free))
1872 		return (TCP_LRO_NO_ENTRIES);
1873 
1874 	/* Start a new segment chain. */
1875 	le = LIST_FIRST(&lc->lro_free);
1876 	LIST_REMOVE(le, next);
1877 	tcp_lro_active_insert(lc, bucket, le);
1878 
1879 	/* Make sure the headers are set. */
1880 	le->inner = pi;
1881 	le->outer = po;
1882 
1883 	/* Store time this entry was allocated. */
1884 	le->alloc_time = lc->lro_last_queue_time;
1885 
1886 	tcp_set_entry_to_mbuf(lc, le, m, th);
1887 
1888 	/* Now set the tail to "m". */
1889 	le->m_last_mbuf = m;
1890 
1891 	return (0);
1892 }
1893 
1894 int
1895 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
1896 {
1897 	int error;
1898 
1899 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1900 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1901 	    (m->m_pkthdr.csum_data != 0xffff)) {
1902 		/*
1903 		 * The checksum either did not have hardware offload
1904 		 * or it was a bad checksum. We can't LRO such
1905 		 * a packet.
1906 		 */
1907 		counter_u64_add(tcp_bad_csums, 1);
1908 		return (TCP_LRO_CANNOT);
1909 	}
1910 	/* get current time */
1911 	binuptime(&lc->lro_last_queue_time);
1912 	CURVNET_SET(lc->ifp->if_vnet);
1913 	error = tcp_lro_rx_common(lc, m, csum, true);
1914 	CURVNET_RESTORE();
1915 
1916 	return (error);
1917 }
1918 
1919 void
1920 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
1921 {
1922 	/* sanity checks */
1923 	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
1924 	    lc->lro_mbuf_max == 0)) {
1925 		/* packet drop */
1926 		m_freem(mb);
1927 		return;
1928 	}
1929 
1930 	/* check if packet is not LRO capable */
1931 	if (__predict_false((lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
1932 		/* input packet to network layer */
1933 		(*lc->ifp->if_input) (lc->ifp, mb);
1934 		return;
1935 	}
1936 
1937 	/* create sequence number */
1938 	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
1939 	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
1940 	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
1941 	    ((uint64_t)lc->lro_mbuf_count);
1942 
1943 	/* enter mbuf */
1944 	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
1945 
1946 	/* flush if array is full */
1947 	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
1948 		tcp_lro_flush_all(lc);
1949 }
1950 
1951 /* end */
1952