xref: /freebsd/sys/netinet/tcp_lro.c (revision 79ac3c12a714bcd3f2354c52d948aed9575c46d6)
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 
105 static unsigned	tcp_lro_entries = TCP_LRO_ENTRIES;
106 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries,
107     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0,
108     "default number of LRO entries");
109 
110 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, fullqueue, CTLFLAG_RD,
111     &tcp_inp_lro_direct_queue, "Number of lro's fully queued to transport");
112 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, wokeup, CTLFLAG_RD,
113     &tcp_inp_lro_wokeup_queue, "Number of lro's where we woke up transport via hpts");
114 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, compressed, CTLFLAG_RD,
115     &tcp_inp_lro_compressed, "Number of lro's compressed and sent to transport");
116 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lockcnt, CTLFLAG_RD,
117     &tcp_inp_lro_locks_taken, "Number of lro's inp_wlocks taken");
118 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, extra_mbuf, CTLFLAG_RD,
119     &tcp_extra_mbuf, "Number of times we had an extra compressed ack dropped into the tp");
120 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, would_have_but, CTLFLAG_RD,
121     &tcp_would_have_but, "Number of times we would have had an extra compressed, but mget failed");
122 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, with_m_ackcmp, CTLFLAG_RD,
123     &tcp_comp_total, "Number of mbufs queued with M_ACKCMP flags set");
124 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, without_m_ackcmp, CTLFLAG_RD,
125     &tcp_uncomp_total, "Number of mbufs queued without M_ACKCMP");
126 
127 void
128 tcp_lro_reg_mbufq(void)
129 {
130 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, 1);
131 }
132 
133 void
134 tcp_lro_dereg_mbufq(void)
135 {
136 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, -1);
137 }
138 
139 static __inline void
140 tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_head *bucket,
141     struct lro_entry *le)
142 {
143 
144 	LIST_INSERT_HEAD(&lc->lro_active, le, next);
145 	LIST_INSERT_HEAD(bucket, le, hash_next);
146 }
147 
148 static __inline void
149 tcp_lro_active_remove(struct lro_entry *le)
150 {
151 
152 	LIST_REMOVE(le, next);		/* active list */
153 	LIST_REMOVE(le, hash_next);	/* hash bucket */
154 }
155 
156 int
157 tcp_lro_init(struct lro_ctrl *lc)
158 {
159 	return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0));
160 }
161 
162 int
163 tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
164     unsigned lro_entries, unsigned lro_mbufs)
165 {
166 	struct lro_entry *le;
167 	size_t size;
168 	unsigned i, elements;
169 
170 	lc->lro_bad_csum = 0;
171 	lc->lro_queued = 0;
172 	lc->lro_flushed = 0;
173 	lc->lro_mbuf_count = 0;
174 	lc->lro_mbuf_max = lro_mbufs;
175 	lc->lro_cnt = lro_entries;
176 	lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
177 	lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
178 	lc->ifp = ifp;
179 	LIST_INIT(&lc->lro_free);
180 	LIST_INIT(&lc->lro_active);
181 
182 	/* create hash table to accelerate entry lookup */
183 	if (lro_entries > lro_mbufs)
184 		elements = lro_entries;
185 	else
186 		elements = lro_mbufs;
187 	lc->lro_hash = phashinit_flags(elements, M_LRO, &lc->lro_hashsz,
188 	    HASH_NOWAIT);
189 	if (lc->lro_hash == NULL) {
190 		memset(lc, 0, sizeof(*lc));
191 		return (ENOMEM);
192 	}
193 
194 	/* compute size to allocate */
195 	size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
196 	    (lro_entries * sizeof(*le));
197 	lc->lro_mbuf_data = (struct lro_mbuf_sort *)
198 	    malloc(size, M_LRO, M_NOWAIT | M_ZERO);
199 
200 	/* check for out of memory */
201 	if (lc->lro_mbuf_data == NULL) {
202 		free(lc->lro_hash, M_LRO);
203 		memset(lc, 0, sizeof(*lc));
204 		return (ENOMEM);
205 	}
206 	/* compute offset for LRO entries */
207 	le = (struct lro_entry *)
208 	    (lc->lro_mbuf_data + lro_mbufs);
209 
210 	/* setup linked list */
211 	for (i = 0; i != lro_entries; i++)
212 		LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
213 
214 	return (0);
215 }
216 
217 struct vxlan_header {
218 	uint32_t	vxlh_flags;
219 	uint32_t	vxlh_vni;
220 };
221 
222 static inline void *
223 tcp_lro_low_level_parser(void *ptr, struct lro_parser *parser, bool update_data, bool is_vxlan)
224 {
225 	const struct ether_vlan_header *eh;
226 	void *old;
227 	uint16_t eth_type;
228 
229 	if (update_data)
230 		memset(parser, 0, sizeof(*parser));
231 
232 	old = ptr;
233 
234 	if (is_vxlan) {
235 		const struct vxlan_header *vxh;
236 		vxh = ptr;
237 		ptr = (uint8_t *)ptr + sizeof(*vxh);
238 		if (update_data) {
239 			parser->data.vxlan_vni =
240 			    vxh->vxlh_vni & htonl(0xffffff00);
241 		}
242 	}
243 
244 	eh = ptr;
245 	if (__predict_false(eh->evl_encap_proto == htons(ETHERTYPE_VLAN))) {
246 		eth_type = eh->evl_proto;
247 		if (update_data) {
248 			/* strip priority and keep VLAN ID only */
249 			parser->data.vlan_id = eh->evl_tag & htons(EVL_VLID_MASK);
250 		}
251 		/* advance to next header */
252 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
253 	} else {
254 		eth_type = eh->evl_encap_proto;
255 		/* advance to next header */
256 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN;
257 	}
258 
259 	switch (eth_type) {
260 #ifdef INET
261 	case htons(ETHERTYPE_IP):
262 		parser->ip4 = ptr;
263 		/* Ensure there are no IPv4 options. */
264 		if ((parser->ip4->ip_hl << 2) != sizeof (*parser->ip4))
265 			break;
266 		/* .. and the packet is not fragmented. */
267 		if (parser->ip4->ip_off & htons(IP_MF|IP_OFFMASK))
268 			break;
269 		ptr = (uint8_t *)ptr + (parser->ip4->ip_hl << 2);
270 		if (update_data) {
271 			parser->data.s_addr.v4 = parser->ip4->ip_src;
272 			parser->data.d_addr.v4 = parser->ip4->ip_dst;
273 		}
274 		switch (parser->ip4->ip_p) {
275 		case IPPROTO_UDP:
276 			parser->udp = ptr;
277 			if (update_data) {
278 				parser->data.lro_type = LRO_TYPE_IPV4_UDP;
279 				parser->data.s_port = parser->udp->uh_sport;
280 				parser->data.d_port = parser->udp->uh_dport;
281 			} else {
282 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_UDP);
283 			}
284 			ptr = ((uint8_t *)ptr + sizeof(*parser->udp));
285 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
286 			return (ptr);
287 		case IPPROTO_TCP:
288 			parser->tcp = ptr;
289 			if (update_data) {
290 				parser->data.lro_type = LRO_TYPE_IPV4_TCP;
291 				parser->data.s_port = parser->tcp->th_sport;
292 				parser->data.d_port = parser->tcp->th_dport;
293 			} else {
294 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_TCP);
295 			}
296 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
297 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
298 			return (ptr);
299 		default:
300 			break;
301 		}
302 		break;
303 #endif
304 #ifdef INET6
305 	case htons(ETHERTYPE_IPV6):
306 		parser->ip6 = ptr;
307 		ptr = (uint8_t *)ptr + sizeof(*parser->ip6);
308 		if (update_data) {
309 			parser->data.s_addr.v6 = parser->ip6->ip6_src;
310 			parser->data.d_addr.v6 = parser->ip6->ip6_dst;
311 		}
312 		switch (parser->ip6->ip6_nxt) {
313 		case IPPROTO_UDP:
314 			parser->udp = ptr;
315 			if (update_data) {
316 				parser->data.lro_type = LRO_TYPE_IPV6_UDP;
317 				parser->data.s_port = parser->udp->uh_sport;
318 				parser->data.d_port = parser->udp->uh_dport;
319 			} else {
320 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_UDP);
321 			}
322 			ptr = (uint8_t *)ptr + sizeof(*parser->udp);
323 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
324 			return (ptr);
325 		case IPPROTO_TCP:
326 			parser->tcp = ptr;
327 			if (update_data) {
328 				parser->data.lro_type = LRO_TYPE_IPV6_TCP;
329 				parser->data.s_port = parser->tcp->th_sport;
330 				parser->data.d_port = parser->tcp->th_dport;
331 			} else {
332 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_TCP);
333 			}
334 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
335 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
336 			return (ptr);
337 		default:
338 			break;
339 		}
340 		break;
341 #endif
342 	default:
343 		break;
344 	}
345 	/* Invalid packet - cannot parse */
346 	return (NULL);
347 }
348 
349 static const int vxlan_csum = CSUM_INNER_L3_CALC | CSUM_INNER_L3_VALID |
350     CSUM_INNER_L4_CALC | CSUM_INNER_L4_VALID;
351 
352 static inline struct lro_parser *
353 tcp_lro_parser(struct mbuf *m, struct lro_parser *po, struct lro_parser *pi, bool update_data)
354 {
355 	void *data_ptr;
356 
357 	/* Try to parse outer headers first. */
358 	data_ptr = tcp_lro_low_level_parser(m->m_data, po, update_data, false);
359 	if (data_ptr == NULL || po->total_hdr_len > m->m_len)
360 		return (NULL);
361 
362 	if (update_data) {
363 		/* Store VLAN ID, if any. */
364 		if (__predict_false(m->m_flags & M_VLANTAG)) {
365 			po->data.vlan_id =
366 			    htons(m->m_pkthdr.ether_vtag) & htons(EVL_VLID_MASK);
367 		}
368 	}
369 
370 	switch (po->data.lro_type) {
371 	case LRO_TYPE_IPV4_UDP:
372 	case LRO_TYPE_IPV6_UDP:
373 		/* Check for VXLAN headers. */
374 		if ((m->m_pkthdr.csum_flags & vxlan_csum) != vxlan_csum)
375 			break;
376 
377 		/* Try to parse inner headers. */
378 		data_ptr = tcp_lro_low_level_parser(data_ptr, pi, update_data, true);
379 		if (data_ptr == NULL || pi->total_hdr_len > m->m_len)
380 			break;
381 
382 		/* Verify supported header types. */
383 		switch (pi->data.lro_type) {
384 		case LRO_TYPE_IPV4_TCP:
385 		case LRO_TYPE_IPV6_TCP:
386 			return (pi);
387 		default:
388 			break;
389 		}
390 		break;
391 	case LRO_TYPE_IPV4_TCP:
392 	case LRO_TYPE_IPV6_TCP:
393 		if (update_data)
394 			memset(pi, 0, sizeof(*pi));
395 		return (po);
396 	default:
397 		break;
398 	}
399 	return (NULL);
400 }
401 
402 static inline int
403 tcp_lro_trim_mbuf_chain(struct mbuf *m, const struct lro_parser *po)
404 {
405 	int len;
406 
407 	switch (po->data.lro_type) {
408 #ifdef INET
409 	case LRO_TYPE_IPV4_TCP:
410 		len = ((uint8_t *)po->ip4 - (uint8_t *)m->m_data) +
411 		    ntohs(po->ip4->ip_len);
412 		break;
413 #endif
414 #ifdef INET6
415 	case LRO_TYPE_IPV6_TCP:
416 		len = ((uint8_t *)po->ip6 - (uint8_t *)m->m_data) +
417 		    ntohs(po->ip6->ip6_plen) + sizeof(*po->ip6);
418 		break;
419 #endif
420 	default:
421 		return (TCP_LRO_CANNOT);
422 	}
423 
424 	/*
425 	 * If the frame is padded beyond the end of the IP packet,
426 	 * then trim the extra bytes off:
427 	 */
428 	if (__predict_true(m->m_pkthdr.len == len)) {
429 		return (0);
430 	} else if (m->m_pkthdr.len > len) {
431 		m_adj(m, len - m->m_pkthdr.len);
432 		return (0);
433 	}
434 	return (TCP_LRO_CANNOT);
435 }
436 
437 static struct tcphdr *
438 tcp_lro_get_th(struct mbuf *m)
439 {
440 	return ((struct tcphdr *)((uint8_t *)m->m_data + m->m_pkthdr.lro_tcp_h_off));
441 }
442 
443 static void
444 lro_free_mbuf_chain(struct mbuf *m)
445 {
446 	struct mbuf *save;
447 
448 	while (m) {
449 		save = m->m_nextpkt;
450 		m->m_nextpkt = NULL;
451 		m_freem(m);
452 		m = save;
453 	}
454 }
455 
456 void
457 tcp_lro_free(struct lro_ctrl *lc)
458 {
459 	struct lro_entry *le;
460 	unsigned x;
461 
462 	/* reset LRO free list */
463 	LIST_INIT(&lc->lro_free);
464 
465 	/* free active mbufs, if any */
466 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
467 		tcp_lro_active_remove(le);
468 		lro_free_mbuf_chain(le->m_head);
469 	}
470 
471 	/* free hash table */
472 	free(lc->lro_hash, M_LRO);
473 	lc->lro_hash = NULL;
474 	lc->lro_hashsz = 0;
475 
476 	/* free mbuf array, if any */
477 	for (x = 0; x != lc->lro_mbuf_count; x++)
478 		m_freem(lc->lro_mbuf_data[x].mb);
479 	lc->lro_mbuf_count = 0;
480 
481 	/* free allocated memory, if any */
482 	free(lc->lro_mbuf_data, M_LRO);
483 	lc->lro_mbuf_data = NULL;
484 }
485 
486 static uint16_t
487 tcp_lro_rx_csum_tcphdr(const struct tcphdr *th)
488 {
489 	const uint16_t *ptr;
490 	uint32_t csum;
491 	uint16_t len;
492 
493 	csum = -th->th_sum;	/* exclude checksum field */
494 	len = th->th_off;
495 	ptr = (const uint16_t *)th;
496 	while (len--) {
497 		csum += *ptr;
498 		ptr++;
499 		csum += *ptr;
500 		ptr++;
501 	}
502 	while (csum > 0xffff)
503 		csum = (csum >> 16) + (csum & 0xffff);
504 
505 	return (csum);
506 }
507 
508 static uint16_t
509 tcp_lro_rx_csum_data(const struct lro_parser *pa, uint16_t tcp_csum)
510 {
511 	uint32_t c;
512 	uint16_t cs;
513 
514 	c = tcp_csum;
515 
516 	switch (pa->data.lro_type) {
517 #ifdef INET6
518 	case LRO_TYPE_IPV6_TCP:
519 		/* Compute full pseudo IPv6 header checksum. */
520 		cs = in6_cksum_pseudo(pa->ip6, ntohs(pa->ip6->ip6_plen), pa->ip6->ip6_nxt, 0);
521 		break;
522 #endif
523 #ifdef INET
524 	case LRO_TYPE_IPV4_TCP:
525 		/* Compute full pseudo IPv4 header checsum. */
526 		cs = in_addword(ntohs(pa->ip4->ip_len) - sizeof(*pa->ip4), IPPROTO_TCP);
527 		cs = in_pseudo(pa->ip4->ip_src.s_addr, pa->ip4->ip_dst.s_addr, htons(cs));
528 		break;
529 #endif
530 	default:
531 		cs = 0;		/* Keep compiler happy. */
532 		break;
533 	}
534 
535 	/* Complement checksum. */
536 	cs = ~cs;
537 	c += cs;
538 
539 	/* Remove TCP header checksum. */
540 	cs = ~tcp_lro_rx_csum_tcphdr(pa->tcp);
541 	c += cs;
542 
543 	/* Compute checksum remainder. */
544 	while (c > 0xffff)
545 		c = (c >> 16) + (c & 0xffff);
546 
547 	return (c);
548 }
549 
550 static void
551 tcp_lro_rx_done(struct lro_ctrl *lc)
552 {
553 	struct lro_entry *le;
554 
555 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
556 		tcp_lro_active_remove(le);
557 		tcp_lro_flush(lc, le);
558 	}
559 }
560 
561 void
562 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
563 {
564 	struct lro_entry *le, *le_tmp;
565 	uint64_t now, tov;
566 	struct bintime bt;
567 
568 	if (LIST_EMPTY(&lc->lro_active))
569 		return;
570 
571 	/* get timeout time and current time in ns */
572 	binuptime(&bt);
573 	now = bintime2ns(&bt);
574 	tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000));
575 	LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
576 		if (now >= (bintime2ns(&le->alloc_time) + tov)) {
577 			tcp_lro_active_remove(le);
578 			tcp_lro_flush(lc, le);
579 		}
580 	}
581 }
582 
583 #ifdef INET
584 static int
585 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4)
586 {
587 	uint16_t csum;
588 
589 	/* Legacy IP has a header checksum that needs to be correct. */
590 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
591 		if (__predict_false((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0)) {
592 			lc->lro_bad_csum++;
593 			return (TCP_LRO_CANNOT);
594 		}
595 	} else {
596 		csum = in_cksum_hdr(ip4);
597 		if (__predict_false(csum != 0)) {
598 			lc->lro_bad_csum++;
599 			return (TCP_LRO_CANNOT);
600 		}
601 	}
602 	return (0);
603 }
604 #endif
605 
606 #ifdef TCPHPTS
607 static void
608 tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
609     const struct lro_entry *le, const struct mbuf *m,
610     int frm, int32_t tcp_data_len, uint32_t th_seq,
611     uint32_t th_ack, uint16_t th_win)
612 {
613 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
614 		union tcp_log_stackspecific log;
615 		struct timeval tv, btv;
616 		uint32_t cts;
617 
618 		cts = tcp_get_usecs(&tv);
619 		memset(&log, 0, sizeof(union tcp_log_stackspecific));
620 		log.u_bbr.flex8 = frm;
621 		log.u_bbr.flex1 = tcp_data_len;
622 		if (m)
623 			log.u_bbr.flex2 = m->m_pkthdr.len;
624 		else
625 			log.u_bbr.flex2 = 0;
626 		log.u_bbr.flex3 = le->m_head->m_pkthdr.lro_nsegs;
627 		log.u_bbr.flex4 = le->m_head->m_pkthdr.lro_tcp_d_len;
628 		if (le->m_head) {
629 			log.u_bbr.flex5 = le->m_head->m_pkthdr.len;
630 			log.u_bbr.delRate = le->m_head->m_flags;
631 			log.u_bbr.rttProp = le->m_head->m_pkthdr.rcv_tstmp;
632 		}
633 		log.u_bbr.inflight = th_seq;
634 		log.u_bbr.timeStamp = cts;
635 		log.u_bbr.epoch = le->next_seq;
636 		log.u_bbr.delivered = th_ack;
637 		log.u_bbr.lt_epoch = le->ack_seq;
638 		log.u_bbr.pacing_gain = th_win;
639 		log.u_bbr.cwnd_gain = le->window;
640 		log.u_bbr.cur_del_rate = (uintptr_t)m;
641 		log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
642 		bintime2timeval(&lc->lro_last_queue_time, &btv);
643 		log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
644 		log.u_bbr.flex7 = le->compressed;
645 		log.u_bbr.pacing_gain = le->uncompressed;
646 		if (in_epoch(net_epoch_preempt))
647 			log.u_bbr.inhpts = 1;
648 		else
649 			log.u_bbr.inhpts = 0;
650 		TCP_LOG_EVENTP(tp, NULL,
651 			       &tp->t_inpcb->inp_socket->so_rcv,
652 			       &tp->t_inpcb->inp_socket->so_snd,
653 			       TCP_LOG_LRO, 0,
654 			       0, &log, false, &tv);
655 	}
656 }
657 #endif
658 
659 static inline void
660 tcp_lro_assign_and_checksum_16(uint16_t *ptr, uint16_t value, uint16_t *psum)
661 {
662 	uint32_t csum;
663 
664 	csum = 0xffff - *ptr + value;
665 	while (csum > 0xffff)
666 		csum = (csum >> 16) + (csum & 0xffff);
667 	*ptr = value;
668 	*psum = csum;
669 }
670 
671 static uint16_t
672 tcp_lro_update_checksum(const struct lro_parser *pa, const struct lro_entry *le,
673     uint16_t payload_len, uint16_t delta_sum)
674 {
675 	uint32_t csum;
676 	uint16_t tlen;
677 	uint16_t temp[5] = {};
678 
679 	switch (pa->data.lro_type) {
680 	case LRO_TYPE_IPV4_TCP:
681 		/* Compute new IPv4 length. */
682 		tlen = (pa->ip4->ip_hl << 2) + (pa->tcp->th_off << 2) + payload_len;
683 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
684 
685 		/* Subtract delta from current IPv4 checksum. */
686 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
687 		while (csum > 0xffff)
688 			csum = (csum >> 16) + (csum & 0xffff);
689 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
690 		goto update_tcp_header;
691 
692 	case LRO_TYPE_IPV6_TCP:
693 		/* Compute new IPv6 length. */
694 		tlen = (pa->tcp->th_off << 2) + payload_len;
695 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
696 		goto update_tcp_header;
697 
698 	case LRO_TYPE_IPV4_UDP:
699 		/* Compute new IPv4 length. */
700 		tlen = (pa->ip4->ip_hl << 2) + sizeof(*pa->udp) + payload_len;
701 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
702 
703 		/* Subtract delta from current IPv4 checksum. */
704 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
705 		while (csum > 0xffff)
706 			csum = (csum >> 16) + (csum & 0xffff);
707 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
708 		goto update_udp_header;
709 
710 	case LRO_TYPE_IPV6_UDP:
711 		/* Compute new IPv6 length. */
712 		tlen = sizeof(*pa->udp) + payload_len;
713 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
714 		goto update_udp_header;
715 
716 	default:
717 		return (0);
718 	}
719 
720 update_tcp_header:
721 	/* Compute current TCP header checksum. */
722 	temp[2] = tcp_lro_rx_csum_tcphdr(pa->tcp);
723 
724 	/* Incorporate the latest ACK into the TCP header. */
725 	pa->tcp->th_ack = le->ack_seq;
726 	pa->tcp->th_win = le->window;
727 
728 	/* Incorporate latest timestamp into the TCP header. */
729 	if (le->timestamp != 0) {
730 		uint32_t *ts_ptr;
731 
732 		ts_ptr = (uint32_t *)(pa->tcp + 1);
733 		ts_ptr[1] = htonl(le->tsval);
734 		ts_ptr[2] = le->tsecr;
735 	}
736 
737 	/* Compute new TCP header checksum. */
738 	temp[3] = tcp_lro_rx_csum_tcphdr(pa->tcp);
739 
740 	/* Compute new TCP checksum. */
741 	csum = pa->tcp->th_sum + 0xffff - delta_sum +
742 	    0xffff - temp[0] + 0xffff - temp[3] + temp[2];
743 	while (csum > 0xffff)
744 		csum = (csum >> 16) + (csum & 0xffff);
745 
746 	/* Assign new TCP checksum. */
747 	tcp_lro_assign_and_checksum_16(&pa->tcp->th_sum, csum, &temp[4]);
748 
749 	/* Compute all modififications affecting next checksum. */
750 	csum = temp[0] + temp[1] + 0xffff - temp[2] +
751 	    temp[3] + temp[4] + delta_sum;
752 	while (csum > 0xffff)
753 		csum = (csum >> 16) + (csum & 0xffff);
754 
755 	/* Return delta checksum to next stage, if any. */
756 	return (csum);
757 
758 update_udp_header:
759 	tlen = sizeof(*pa->udp) + payload_len;
760 	/* Assign new UDP length and compute checksum delta. */
761 	tcp_lro_assign_and_checksum_16(&pa->udp->uh_ulen, htons(tlen), &temp[2]);
762 
763 	/* Check if there is a UDP checksum. */
764 	if (__predict_false(pa->udp->uh_sum != 0)) {
765 		/* Compute new UDP checksum. */
766 		csum = pa->udp->uh_sum + 0xffff - delta_sum +
767 		    0xffff - temp[0] + 0xffff - temp[2];
768 		while (csum > 0xffff)
769 			csum = (csum >> 16) + (csum & 0xffff);
770 		/* Assign new UDP checksum. */
771 		tcp_lro_assign_and_checksum_16(&pa->udp->uh_sum, csum, &temp[3]);
772 	}
773 
774 	/* Compute all modififications affecting next checksum. */
775 	csum = temp[0] + temp[1] + temp[2] + temp[3] + delta_sum;
776 	while (csum > 0xffff)
777 		csum = (csum >> 16) + (csum & 0xffff);
778 
779 	/* Return delta checksum to next stage, if any. */
780 	return (csum);
781 }
782 
783 static void
784 tcp_flush_out_entry(struct lro_ctrl *lc, struct lro_entry *le)
785 {
786 	/* Check if we need to recompute any checksums. */
787 	if (le->m_head->m_pkthdr.lro_nsegs > 1) {
788 		uint16_t csum;
789 
790 		switch (le->inner.data.lro_type) {
791 		case LRO_TYPE_IPV4_TCP:
792 			csum = tcp_lro_update_checksum(&le->inner, le,
793 			    le->m_head->m_pkthdr.lro_tcp_d_len,
794 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
795 			csum = tcp_lro_update_checksum(&le->outer, NULL,
796 			    le->m_head->m_pkthdr.lro_tcp_d_len +
797 			    le->inner.total_hdr_len, csum);
798 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
799 			    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
800 			le->m_head->m_pkthdr.csum_data = 0xffff;
801 			break;
802 		case LRO_TYPE_IPV6_TCP:
803 			csum = tcp_lro_update_checksum(&le->inner, le,
804 			    le->m_head->m_pkthdr.lro_tcp_d_len,
805 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
806 			csum = tcp_lro_update_checksum(&le->outer, NULL,
807 			    le->m_head->m_pkthdr.lro_tcp_d_len +
808 			    le->inner.total_hdr_len, csum);
809 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
810 			    CSUM_PSEUDO_HDR;
811 			le->m_head->m_pkthdr.csum_data = 0xffff;
812 			break;
813 		case LRO_TYPE_NONE:
814 			switch (le->outer.data.lro_type) {
815 			case LRO_TYPE_IPV4_TCP:
816 				csum = tcp_lro_update_checksum(&le->outer, le,
817 				    le->m_head->m_pkthdr.lro_tcp_d_len,
818 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
819 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
820 				    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
821 				le->m_head->m_pkthdr.csum_data = 0xffff;
822 				break;
823 			case LRO_TYPE_IPV6_TCP:
824 				csum = tcp_lro_update_checksum(&le->outer, le,
825 				    le->m_head->m_pkthdr.lro_tcp_d_len,
826 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
827 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
828 				    CSUM_PSEUDO_HDR;
829 				le->m_head->m_pkthdr.csum_data = 0xffff;
830 				break;
831 			default:
832 				break;
833 			}
834 			break;
835 		default:
836 			break;
837 		}
838 	}
839 
840 	/*
841 	 * Break any chain, this is not set to NULL on the singleton
842 	 * case m_nextpkt points to m_head. Other case set them
843 	 * m_nextpkt to NULL in push_and_replace.
844 	 */
845 	le->m_head->m_nextpkt = NULL;
846 	lc->lro_queued += le->m_head->m_pkthdr.lro_nsegs;
847 	(*lc->ifp->if_input)(lc->ifp, le->m_head);
848 }
849 
850 static void
851 tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le,
852     struct mbuf *m, struct tcphdr *th)
853 {
854 	uint32_t *ts_ptr;
855 	uint16_t tcp_data_len;
856 	uint16_t tcp_opt_len;
857 
858 	ts_ptr = (uint32_t *)(th + 1);
859 	tcp_opt_len = (th->th_off << 2);
860 	tcp_opt_len -= sizeof(*th);
861 
862 	/* Check if there is a timestamp option. */
863 	if (tcp_opt_len == 0 ||
864 	    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
865 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
866 		/* We failed to find the timestamp option. */
867 		le->timestamp = 0;
868 	} else {
869 		le->timestamp = 1;
870 		le->tsval = ntohl(*(ts_ptr + 1));
871 		le->tsecr = *(ts_ptr + 2);
872 	}
873 
874 	tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
875 
876 	/* Pull out TCP sequence numbers and window size. */
877 	le->next_seq = ntohl(th->th_seq) + tcp_data_len;
878 	le->ack_seq = th->th_ack;
879 	le->window = th->th_win;
880 
881 	/* Setup new data pointers. */
882 	le->m_head = m;
883 	le->m_tail = m_last(m);
884 }
885 
886 static void
887 tcp_push_and_replace(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m)
888 {
889 	struct lro_parser *pa;
890 
891 	/*
892 	 * Push up the stack of the current entry
893 	 * and replace it with "m".
894 	 */
895 	struct mbuf *msave;
896 
897 	/* Grab off the next and save it */
898 	msave = le->m_head->m_nextpkt;
899 	le->m_head->m_nextpkt = NULL;
900 
901 	/* Now push out the old entry */
902 	tcp_flush_out_entry(lc, le);
903 
904 	/* Re-parse new header, should not fail. */
905 	pa = tcp_lro_parser(m, &le->outer, &le->inner, false);
906 	KASSERT(pa != NULL,
907 	    ("tcp_push_and_replace: LRO parser failed on m=%p\n", m));
908 
909 	/*
910 	 * Now to replace the data properly in the entry
911 	 * we have to reset the TCP header and
912 	 * other fields.
913 	 */
914 	tcp_set_entry_to_mbuf(lc, le, m, pa->tcp);
915 
916 	/* Restore the next list */
917 	m->m_nextpkt = msave;
918 }
919 
920 static void
921 tcp_lro_mbuf_append_pkthdr(struct mbuf *m, const struct mbuf *p)
922 {
923 	uint32_t csum;
924 
925 	if (m->m_pkthdr.lro_nsegs == 1) {
926 		/* Compute relative checksum. */
927 		csum = p->m_pkthdr.lro_tcp_d_csum;
928 	} else {
929 		/* Merge TCP data checksums. */
930 		csum = (uint32_t)m->m_pkthdr.lro_tcp_d_csum +
931 		    (uint32_t)p->m_pkthdr.lro_tcp_d_csum;
932 		while (csum > 0xffff)
933 			csum = (csum >> 16) + (csum & 0xffff);
934 	}
935 
936 	/* Update various counters. */
937 	m->m_pkthdr.len += p->m_pkthdr.lro_tcp_d_len;
938 	m->m_pkthdr.lro_tcp_d_csum = csum;
939 	m->m_pkthdr.lro_tcp_d_len += p->m_pkthdr.lro_tcp_d_len;
940 	m->m_pkthdr.lro_nsegs += p->m_pkthdr.lro_nsegs;
941 }
942 
943 static void
944 tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le)
945 {
946 	/*
947 	 * Walk through the mbuf chain we
948 	 * have on tap and compress/condense
949 	 * as required.
950 	 */
951 	uint32_t *ts_ptr;
952 	struct mbuf *m;
953 	struct tcphdr *th;
954 	uint32_t tcp_data_len_total;
955 	uint32_t tcp_data_seg_total;
956 	uint16_t tcp_data_len;
957 	uint16_t tcp_opt_len;
958 
959 	/*
960 	 * First we must check the lead (m_head)
961 	 * we must make sure that it is *not*
962 	 * something that should be sent up
963 	 * right away (sack etc).
964 	 */
965 again:
966 	m = le->m_head->m_nextpkt;
967 	if (m == NULL) {
968 		/* Just one left. */
969 		return;
970 	}
971 
972 	th = tcp_lro_get_th(m);
973 	tcp_opt_len = (th->th_off << 2);
974 	tcp_opt_len -= sizeof(*th);
975 	ts_ptr = (uint32_t *)(th + 1);
976 
977 	if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
978 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
979 		/*
980 		 * Its not the timestamp. We can't
981 		 * use this guy as the head.
982 		 */
983 		le->m_head->m_nextpkt = m->m_nextpkt;
984 		tcp_push_and_replace(lc, le, m);
985 		goto again;
986 	}
987 	if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
988 		/*
989 		 * Make sure that previously seen segements/ACKs are delivered
990 		 * before this segment, e.g. FIN.
991 		 */
992 		le->m_head->m_nextpkt = m->m_nextpkt;
993 		tcp_push_and_replace(lc, le, m);
994 		goto again;
995 	}
996 	while((m = le->m_head->m_nextpkt) != NULL) {
997 		/*
998 		 * condense m into le, first
999 		 * pull m out of the list.
1000 		 */
1001 		le->m_head->m_nextpkt = m->m_nextpkt;
1002 		m->m_nextpkt = NULL;
1003 		/* Setup my data */
1004 		tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
1005 		th = tcp_lro_get_th(m);
1006 		ts_ptr = (uint32_t *)(th + 1);
1007 		tcp_opt_len = (th->th_off << 2);
1008 		tcp_opt_len -= sizeof(*th);
1009 		tcp_data_len_total = le->m_head->m_pkthdr.lro_tcp_d_len + tcp_data_len;
1010 		tcp_data_seg_total = le->m_head->m_pkthdr.lro_nsegs + m->m_pkthdr.lro_nsegs;
1011 
1012 		if (tcp_data_seg_total >= lc->lro_ackcnt_lim ||
1013 		    tcp_data_len_total >= lc->lro_length_lim) {
1014 			/* Flush now if appending will result in overflow. */
1015 			tcp_push_and_replace(lc, le, m);
1016 			goto again;
1017 		}
1018 		if (tcp_opt_len != 0 &&
1019 		    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1020 		    *ts_ptr != TCP_LRO_TS_OPTION)) {
1021 			/*
1022 			 * Maybe a sack in the new one? We need to
1023 			 * start all over after flushing the
1024 			 * current le. We will go up to the beginning
1025 			 * and flush it (calling the replace again possibly
1026 			 * or just returning).
1027 			 */
1028 			tcp_push_and_replace(lc, le, m);
1029 			goto again;
1030 		}
1031 		if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
1032 			tcp_push_and_replace(lc, le, m);
1033 			goto again;
1034 		}
1035 		if (tcp_opt_len != 0) {
1036 			uint32_t tsval = ntohl(*(ts_ptr + 1));
1037 			/* Make sure timestamp values are increasing. */
1038 			if (TSTMP_GT(le->tsval, tsval))  {
1039 				tcp_push_and_replace(lc, le, m);
1040 				goto again;
1041 			}
1042 			le->tsval = tsval;
1043 			le->tsecr = *(ts_ptr + 2);
1044 		}
1045 		/* Try to append the new segment. */
1046 		if (__predict_false(ntohl(th->th_seq) != le->next_seq ||
1047 				    (tcp_data_len == 0 &&
1048 				     le->ack_seq == th->th_ack &&
1049 				     le->window == th->th_win))) {
1050 			/* Out of order packet or duplicate ACK. */
1051 			tcp_push_and_replace(lc, le, m);
1052 			goto again;
1053 		}
1054 		if (tcp_data_len != 0 ||
1055 		    SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1056 			le->next_seq += tcp_data_len;
1057 			le->ack_seq = th->th_ack;
1058 			le->window = th->th_win;
1059 		} else if (th->th_ack == le->ack_seq) {
1060 			le->window = WIN_MAX(le->window, th->th_win);
1061 		}
1062 
1063 		if (tcp_data_len == 0) {
1064 			m_freem(m);
1065 			continue;
1066 		}
1067 
1068 		/* Merge TCP data checksum and length to head mbuf. */
1069 		tcp_lro_mbuf_append_pkthdr(le->m_head, m);
1070 
1071 		/*
1072 		 * Adjust the mbuf so that m_data points to the first byte of
1073 		 * the ULP payload.  Adjust the mbuf to avoid complications and
1074 		 * append new segment to existing mbuf chain.
1075 		 */
1076 		m_adj(m, m->m_pkthdr.len - tcp_data_len);
1077 		m_demote_pkthdr(m);
1078 		le->m_tail->m_next = m;
1079 		le->m_tail = m_last(m);
1080 	}
1081 }
1082 
1083 #ifdef TCPHPTS
1084 static void
1085 tcp_queue_pkts(struct inpcb *inp, struct tcpcb *tp, struct lro_entry *le)
1086 {
1087 	INP_WLOCK_ASSERT(inp);
1088 	if (tp->t_in_pkt == NULL) {
1089 		/* Nothing yet there */
1090 		tp->t_in_pkt = le->m_head;
1091 		tp->t_tail_pkt = le->m_last_mbuf;
1092 	} else {
1093 		/* Already some there */
1094 		tp->t_tail_pkt->m_nextpkt = le->m_head;
1095 		tp->t_tail_pkt = le->m_last_mbuf;
1096 	}
1097 	le->m_head = NULL;
1098 	le->m_last_mbuf = NULL;
1099 }
1100 
1101 static struct mbuf *
1102 tcp_lro_get_last_if_ackcmp(struct lro_ctrl *lc, struct lro_entry *le,
1103     struct inpcb *inp, int32_t *new_m)
1104 {
1105 	struct tcpcb *tp;
1106 	struct mbuf *m;
1107 
1108 	tp = intotcpcb(inp);
1109 	if (__predict_false(tp == NULL))
1110 		return (NULL);
1111 
1112 	/* Look at the last mbuf if any in queue */
1113 	m = tp->t_tail_pkt;
1114 	if (m != NULL && (m->m_flags & M_ACKCMP) != 0) {
1115 		if (M_TRAILINGSPACE(m) >= sizeof(struct tcp_ackent)) {
1116 			tcp_lro_log(tp, lc, le, NULL, 23, 0, 0, 0, 0);
1117 			*new_m = 0;
1118 			counter_u64_add(tcp_extra_mbuf, 1);
1119 			return (m);
1120 		} else {
1121 			/* Mark we ran out of space */
1122 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1123 		}
1124 	}
1125 	/* Decide mbuf size. */
1126 	if (inp->inp_flags2 & INP_MBUF_L_ACKS)
1127 		m = m_getcl(M_NOWAIT, MT_DATA, M_ACKCMP | M_PKTHDR);
1128 	else
1129 		m = m_gethdr(M_NOWAIT, MT_DATA);
1130 
1131 	if (__predict_false(m == NULL)) {
1132 		counter_u64_add(tcp_would_have_but, 1);
1133 		return (NULL);
1134 	}
1135 	counter_u64_add(tcp_comp_total, 1);
1136 	m->m_flags |= M_ACKCMP;
1137 	*new_m = 1;
1138 	return (m);
1139 }
1140 
1141 static struct inpcb *
1142 tcp_lro_lookup(struct ifnet *ifp, struct lro_parser *pa)
1143 {
1144 	struct inpcb *inp;
1145 
1146 	NET_EPOCH_ASSERT();
1147 
1148 	switch (pa->data.lro_type) {
1149 #ifdef INET6
1150 	case LRO_TYPE_IPV6_TCP:
1151 		inp = in6_pcblookup(&V_tcbinfo,
1152 		    &pa->data.s_addr.v6,
1153 		    pa->data.s_port,
1154 		    &pa->data.d_addr.v6,
1155 		    pa->data.d_port,
1156 		    INPLOOKUP_WLOCKPCB,
1157 		    ifp);
1158 		break;
1159 #endif
1160 #ifdef INET
1161 	case LRO_TYPE_IPV4_TCP:
1162 		inp = in_pcblookup(&V_tcbinfo,
1163 		    pa->data.s_addr.v4,
1164 		    pa->data.s_port,
1165 		    pa->data.d_addr.v4,
1166 		    pa->data.d_port,
1167 		    INPLOOKUP_WLOCKPCB,
1168 		    ifp);
1169 		break;
1170 #endif
1171 	default:
1172 		inp = NULL;
1173 		break;
1174 	}
1175 	return (inp);
1176 }
1177 
1178 static inline bool
1179 tcp_lro_ack_valid(struct mbuf *m, struct tcphdr *th, uint32_t **ppts, bool *other_opts)
1180 {
1181 	/*
1182 	 * This function returns two bits of valuable information.
1183 	 * a) Is what is present capable of being ack-compressed,
1184 	 *    we can ack-compress if there is no options or just
1185 	 *    a timestamp option, and of course the th_flags must
1186 	 *    be correct as well.
1187 	 * b) Our other options present such as SACK. This is
1188 	 *    used to determine if we want to wakeup or not.
1189 	 */
1190 	bool ret = true;
1191 
1192 	switch (th->th_off << 2) {
1193 	case (sizeof(*th) + TCPOLEN_TSTAMP_APPA):
1194 		*ppts = (uint32_t *)(th + 1);
1195 		/* Check if we have only one timestamp option. */
1196 		if (**ppts == TCP_LRO_TS_OPTION)
1197 			*other_opts = false;
1198 		else {
1199 			*other_opts = true;
1200 			ret = false;
1201 		}
1202 		break;
1203 	case (sizeof(*th)):
1204 		/* No options. */
1205 		*ppts = NULL;
1206 		*other_opts = false;
1207 		break;
1208 	default:
1209 		*ppts = NULL;
1210 		*other_opts = true;
1211 		ret = false;
1212 		break;
1213 	}
1214 	/* For ACKCMP we only accept ACK, PUSH, ECE and CWR. */
1215 	if ((th->th_flags & ~(TH_ACK | TH_PUSH | TH_ECE | TH_CWR)) != 0)
1216 		ret = false;
1217 	/* If it has data on it we cannot compress it */
1218 	if (m->m_pkthdr.lro_tcp_d_len)
1219 		ret = false;
1220 
1221 	/* ACK flag must be set. */
1222 	if (!(th->th_flags & TH_ACK))
1223 		ret = false;
1224 	return (ret);
1225 }
1226 
1227 static int
1228 tcp_lro_flush_tcphpts(struct lro_ctrl *lc, struct lro_entry *le)
1229 {
1230 	struct inpcb *inp;
1231 	struct tcpcb *tp;
1232 	struct mbuf **pp, *cmp, *mv_to;
1233 	bool bpf_req, should_wake;
1234 
1235 	/* Check if packet doesn't belongs to our network interface. */
1236 	if ((tcplro_stacks_wanting_mbufq == 0) ||
1237 	    (le->outer.data.vlan_id != 0) ||
1238 	    (le->inner.data.lro_type != LRO_TYPE_NONE))
1239 		return (TCP_LRO_CANNOT);
1240 
1241 #ifdef INET6
1242 	/*
1243 	 * Be proactive about unspecified IPv6 address in source. As
1244 	 * we use all-zero to indicate unbounded/unconnected pcb,
1245 	 * unspecified IPv6 address can be used to confuse us.
1246 	 *
1247 	 * Note that packets with unspecified IPv6 destination is
1248 	 * already dropped in ip6_input.
1249 	 */
1250 	if (__predict_false(le->outer.data.lro_type == LRO_TYPE_IPV6_TCP &&
1251 	    IN6_IS_ADDR_UNSPECIFIED(&le->outer.data.s_addr.v6)))
1252 		return (TCP_LRO_CANNOT);
1253 
1254 	if (__predict_false(le->inner.data.lro_type == LRO_TYPE_IPV6_TCP &&
1255 	    IN6_IS_ADDR_UNSPECIFIED(&le->inner.data.s_addr.v6)))
1256 		return (TCP_LRO_CANNOT);
1257 #endif
1258 	/* Lookup inp, if any. */
1259 	inp = tcp_lro_lookup(lc->ifp,
1260 	    (le->inner.data.lro_type == LRO_TYPE_NONE) ? &le->outer : &le->inner);
1261 	if (inp == NULL)
1262 		return (TCP_LRO_CANNOT);
1263 
1264 	counter_u64_add(tcp_inp_lro_locks_taken, 1);
1265 
1266 	/* Get TCP control structure. */
1267 	tp = intotcpcb(inp);
1268 
1269 	/* Check if the inp is dead, Jim. */
1270 	if (tp == NULL ||
1271 	    (inp->inp_flags & (INP_DROPPED | INP_TIMEWAIT)) ||
1272 	    (inp->inp_flags2 & INP_FREED)) {
1273 		INP_WUNLOCK(inp);
1274 		return (TCP_LRO_CANNOT);
1275 	}
1276 
1277 	/* Check if the transport doesn't support the needed optimizations. */
1278 	if ((inp->inp_flags2 & (INP_SUPPORTS_MBUFQ | INP_MBUF_ACKCMP)) == 0) {
1279 		INP_WUNLOCK(inp);
1280 		return (TCP_LRO_CANNOT);
1281 	}
1282 
1283 	if (inp->inp_flags2 & INP_MBUF_QUEUE_READY)
1284 		should_wake = false;
1285 	else
1286 		should_wake = true;
1287 	/* Check if packets should be tapped to BPF. */
1288 	bpf_req = bpf_peers_present(lc->ifp->if_bpf);
1289 
1290 	/* Strip and compress all the incoming packets. */
1291 	cmp = NULL;
1292 	for (pp = &le->m_head; *pp != NULL; ) {
1293 		mv_to = NULL;
1294 		if (do_bpf_strip_and_compress(inp, lc, le, pp,
1295 			 &cmp, &mv_to, &should_wake, bpf_req ) == false) {
1296 			/* Advance to next mbuf. */
1297 			pp = &(*pp)->m_nextpkt;
1298 		} else if (mv_to != NULL) {
1299 			/* We are asked to move pp up */
1300 			pp = &mv_to->m_nextpkt;
1301 		}
1302 	}
1303 	/* Update "m_last_mbuf", if any. */
1304 	if (pp == &le->m_head)
1305 		le->m_last_mbuf = *pp;
1306 	else
1307 		le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
1308 
1309 	/* Check if any data mbufs left. */
1310 	if (le->m_head != NULL) {
1311 		counter_u64_add(tcp_inp_lro_direct_queue, 1);
1312 		tcp_lro_log(tp, lc, le, NULL, 22, 1,
1313 			    inp->inp_flags2, inp->inp_in_input, 1);
1314 		tcp_queue_pkts(inp, tp, le);
1315 	}
1316 	if (should_wake) {
1317 		/* Wakeup */
1318 		counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
1319 		if ((*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0))
1320 			inp = NULL;
1321 	}
1322 	if (inp != NULL)
1323 		INP_WUNLOCK(inp);
1324 	return (0);	/* Success. */
1325 }
1326 #endif
1327 
1328 void
1329 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
1330 {
1331 	/* Only optimise if there are multiple packets waiting. */
1332 #ifdef TCPHPTS
1333 	int error;
1334 
1335 	CURVNET_SET(lc->ifp->if_vnet);
1336 	error = tcp_lro_flush_tcphpts(lc, le);
1337 	CURVNET_RESTORE();
1338 	if (error != 0) {
1339 #endif
1340 		tcp_lro_condense(lc, le);
1341 		tcp_flush_out_entry(lc, le);
1342 #ifdef TCPHPTS
1343 	}
1344 #endif
1345 	lc->lro_flushed++;
1346 	bzero(le, sizeof(*le));
1347 	LIST_INSERT_HEAD(&lc->lro_free, le, next);
1348 }
1349 
1350 #ifdef HAVE_INLINE_FLSLL
1351 #define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
1352 #else
1353 static inline uint64_t
1354 tcp_lro_msb_64(uint64_t x)
1355 {
1356 	x |= (x >> 1);
1357 	x |= (x >> 2);
1358 	x |= (x >> 4);
1359 	x |= (x >> 8);
1360 	x |= (x >> 16);
1361 	x |= (x >> 32);
1362 	return (x & ~(x >> 1));
1363 }
1364 #endif
1365 
1366 /*
1367  * The tcp_lro_sort() routine is comparable to qsort(), except it has
1368  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
1369  * number of elements to sort and 64 is the number of sequence bits
1370  * available. The algorithm is bit-slicing the 64-bit sequence number,
1371  * sorting one bit at a time from the most significant bit until the
1372  * least significant one, skipping the constant bits. This is
1373  * typically called a radix sort.
1374  */
1375 static void
1376 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
1377 {
1378 	struct lro_mbuf_sort temp;
1379 	uint64_t ones;
1380 	uint64_t zeros;
1381 	uint32_t x;
1382 	uint32_t y;
1383 
1384 repeat:
1385 	/* for small arrays insertion sort is faster */
1386 	if (size <= 12) {
1387 		for (x = 1; x < size; x++) {
1388 			temp = parray[x];
1389 			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
1390 				parray[y] = parray[y - 1];
1391 			parray[y] = temp;
1392 		}
1393 		return;
1394 	}
1395 
1396 	/* compute sequence bits which are constant */
1397 	ones = 0;
1398 	zeros = 0;
1399 	for (x = 0; x != size; x++) {
1400 		ones |= parray[x].seq;
1401 		zeros |= ~parray[x].seq;
1402 	}
1403 
1404 	/* compute bits which are not constant into "ones" */
1405 	ones &= zeros;
1406 	if (ones == 0)
1407 		return;
1408 
1409 	/* pick the most significant bit which is not constant */
1410 	ones = tcp_lro_msb_64(ones);
1411 
1412 	/*
1413 	 * Move entries having cleared sequence bits to the beginning
1414 	 * of the array:
1415 	 */
1416 	for (x = y = 0; y != size; y++) {
1417 		/* skip set bits */
1418 		if (parray[y].seq & ones)
1419 			continue;
1420 		/* swap entries */
1421 		temp = parray[x];
1422 		parray[x] = parray[y];
1423 		parray[y] = temp;
1424 		x++;
1425 	}
1426 
1427 	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
1428 
1429 	/* sort zeros */
1430 	tcp_lro_sort(parray, x);
1431 
1432 	/* sort ones */
1433 	parray += x;
1434 	size -= x;
1435 	goto repeat;
1436 }
1437 
1438 void
1439 tcp_lro_flush_all(struct lro_ctrl *lc)
1440 {
1441 	uint64_t seq;
1442 	uint64_t nseq;
1443 	unsigned x;
1444 
1445 	/* check if no mbufs to flush */
1446 	if (lc->lro_mbuf_count == 0)
1447 		goto done;
1448 
1449 	CURVNET_SET(lc->ifp->if_vnet);
1450 
1451 	/* get current time */
1452 	binuptime(&lc->lro_last_queue_time);
1453 
1454 	/* sort all mbufs according to stream */
1455 	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
1456 
1457 	/* input data into LRO engine, stream by stream */
1458 	seq = 0;
1459 	for (x = 0; x != lc->lro_mbuf_count; x++) {
1460 		struct mbuf *mb;
1461 
1462 		/* get mbuf */
1463 		mb = lc->lro_mbuf_data[x].mb;
1464 
1465 		/* get sequence number, masking away the packet index */
1466 		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
1467 
1468 		/* check for new stream */
1469 		if (seq != nseq) {
1470 			seq = nseq;
1471 
1472 			/* flush active streams */
1473 			tcp_lro_rx_done(lc);
1474 		}
1475 
1476 		/* add packet to LRO engine */
1477 		if (tcp_lro_rx_common(lc, mb, 0, false) != 0) {
1478 			/* input packet to network layer */
1479 			(*lc->ifp->if_input)(lc->ifp, mb);
1480 			lc->lro_queued++;
1481 			lc->lro_flushed++;
1482 		}
1483 	}
1484 	CURVNET_RESTORE();
1485 done:
1486 	/* flush active streams */
1487 	tcp_lro_rx_done(lc);
1488 
1489 	lc->lro_mbuf_count = 0;
1490 }
1491 
1492 #ifdef TCPHPTS
1493 static void
1494 build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
1495     uint32_t *ts_ptr, uint16_t iptos)
1496 {
1497 	/*
1498 	 * Given a TCP ACK, summarize it down into the small TCP ACK
1499 	 * entry.
1500 	 */
1501 	ae->timestamp = m->m_pkthdr.rcv_tstmp;
1502 	if (m->m_flags & M_TSTMP_LRO)
1503 		ae->flags = TSTMP_LRO;
1504 	else if (m->m_flags & M_TSTMP)
1505 		ae->flags = TSTMP_HDWR;
1506 	ae->seq = ntohl(th->th_seq);
1507 	ae->ack = ntohl(th->th_ack);
1508 	ae->flags |= th->th_flags;
1509 	if (ts_ptr != NULL) {
1510 		ae->ts_value = ntohl(ts_ptr[1]);
1511 		ae->ts_echo = ntohl(ts_ptr[2]);
1512 		ae->flags |= HAS_TSTMP;
1513 	}
1514 	ae->win = ntohs(th->th_win);
1515 	ae->codepoint = iptos;
1516 }
1517 
1518 /*
1519  * Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
1520  * and strip all, but the IPv4/IPv6 header.
1521  */
1522 static bool
1523 do_bpf_strip_and_compress(struct inpcb *inp, struct lro_ctrl *lc,
1524     struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp, struct mbuf **mv_to,
1525     bool *should_wake, bool bpf_req)
1526 {
1527 	union {
1528 		void *ptr;
1529 		struct ip *ip4;
1530 		struct ip6_hdr *ip6;
1531 	} l3;
1532 	struct mbuf *m;
1533 	struct mbuf *nm;
1534 	struct tcphdr *th;
1535 	struct tcp_ackent *ack_ent;
1536 	uint32_t *ts_ptr;
1537 	int32_t n_mbuf;
1538 	bool other_opts, can_compress;
1539 	uint16_t lro_type;
1540 	uint16_t iptos;
1541 	int tcp_hdr_offset;
1542 	int idx;
1543 
1544 	/* Get current mbuf. */
1545 	m = *pp;
1546 
1547 	/* Let the BPF see the packet */
1548 	if (__predict_false(bpf_req))
1549 		ETHER_BPF_MTAP(lc->ifp, m);
1550 
1551 	tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
1552 	lro_type = le->inner.data.lro_type;
1553 	switch (lro_type) {
1554 	case LRO_TYPE_NONE:
1555 		lro_type = le->outer.data.lro_type;
1556 		switch (lro_type) {
1557 		case LRO_TYPE_IPV4_TCP:
1558 			tcp_hdr_offset -= sizeof(*le->outer.ip4);
1559 			m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1560 			break;
1561 		case LRO_TYPE_IPV6_TCP:
1562 			tcp_hdr_offset -= sizeof(*le->outer.ip6);
1563 			m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1564 			break;
1565 		default:
1566 			goto compressed;
1567 		}
1568 		break;
1569 	case LRO_TYPE_IPV4_TCP:
1570 		tcp_hdr_offset -= sizeof(*le->outer.ip4);
1571 		m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1572 		break;
1573 	case LRO_TYPE_IPV6_TCP:
1574 		tcp_hdr_offset -= sizeof(*le->outer.ip6);
1575 		m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1576 		break;
1577 	default:
1578 		goto compressed;
1579 	}
1580 
1581 	MPASS(tcp_hdr_offset >= 0);
1582 
1583 	m_adj(m, tcp_hdr_offset);
1584 	m->m_flags |= M_LRO_EHDRSTRP;
1585 	m->m_flags &= ~M_ACKCMP;
1586 	m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
1587 
1588 	th = tcp_lro_get_th(m);
1589 
1590 	th->th_sum = 0;		/* TCP checksum is valid. */
1591 
1592 	/* Check if ACK can be compressed */
1593 	can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
1594 
1595 	/* Now lets look at the should wake states */
1596 	if ((other_opts == true) &&
1597 	    ((inp->inp_flags2 & INP_DONT_SACK_QUEUE) == 0)) {
1598 		/*
1599 		 * If there are other options (SACK?) and the
1600 		 * tcp endpoint has not expressly told us it does
1601 		 * not care about SACKS, then we should wake up.
1602 		 */
1603 		*should_wake = true;
1604 	}
1605 	/* Is the ack compressable? */
1606 	if (can_compress == false)
1607 		goto done;
1608 	/* Does the TCP endpoint support ACK compression? */
1609 	if ((inp->inp_flags2 & INP_MBUF_ACKCMP) == 0)
1610 		goto done;
1611 
1612 	/* Lets get the TOS/traffic class field */
1613 	l3.ptr = mtod(m, void *);
1614 	switch (lro_type) {
1615 	case LRO_TYPE_IPV4_TCP:
1616 		iptos = l3.ip4->ip_tos;
1617 		break;
1618 	case LRO_TYPE_IPV6_TCP:
1619 		iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
1620 		break;
1621 	default:
1622 		iptos = 0;	/* Keep compiler happy. */
1623 		break;
1624 	}
1625 	/* Now lets get space if we don't have some already */
1626 	if (*cmp == NULL) {
1627 new_one:
1628 		nm = tcp_lro_get_last_if_ackcmp(lc, le, inp, &n_mbuf);
1629 		if (__predict_false(nm == NULL))
1630 			goto done;
1631 		*cmp = nm;
1632 		if (n_mbuf) {
1633 			/*
1634 			 *  Link in the new cmp ack to our in-order place,
1635 			 * first set our cmp ack's next to where we are.
1636 			 */
1637 			nm->m_nextpkt = m;
1638 			(*pp) = nm;
1639 			/*
1640 			 * Set it up so mv_to is advanced to our
1641 			 * compressed ack. This way the caller can
1642 			 * advance pp to the right place.
1643 			 */
1644 			*mv_to = nm;
1645 			/*
1646 			 * Advance it here locally as well.
1647 			 */
1648 			pp = &nm->m_nextpkt;
1649 		}
1650 	} else {
1651 		/* We have one already we are working on */
1652 		nm = *cmp;
1653 		if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
1654 			/* We ran out of space */
1655 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1656 			goto new_one;
1657 		}
1658 	}
1659 	MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
1660 	counter_u64_add(tcp_inp_lro_compressed, 1);
1661 	le->compressed++;
1662 	/* We can add in to the one on the tail */
1663 	ack_ent = mtod(nm, struct tcp_ackent *);
1664 	idx = (nm->m_len / sizeof(struct tcp_ackent));
1665 	build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
1666 
1667 	/* Bump the size of both pkt-hdr and len */
1668 	nm->m_len += sizeof(struct tcp_ackent);
1669 	nm->m_pkthdr.len += sizeof(struct tcp_ackent);
1670 compressed:
1671 	/* Advance to next mbuf before freeing. */
1672 	*pp = m->m_nextpkt;
1673 	m->m_nextpkt = NULL;
1674 	m_freem(m);
1675 	return (true);
1676 done:
1677 	counter_u64_add(tcp_uncomp_total, 1);
1678 	le->uncompressed++;
1679 	return (false);
1680 }
1681 #endif
1682 
1683 static struct lro_head *
1684 tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser)
1685 {
1686 	u_long hash;
1687 
1688 	if (M_HASHTYPE_ISHASH(m)) {
1689 		hash = m->m_pkthdr.flowid;
1690 	} else {
1691 		for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++)
1692 			hash += parser->data.raw[i];
1693 	}
1694 	return (&lc->lro_hash[hash % lc->lro_hashsz]);
1695 }
1696 
1697 static int
1698 tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash)
1699 {
1700 	struct lro_parser pi;	/* inner address data */
1701 	struct lro_parser po;	/* outer address data */
1702 	struct lro_parser *pa;	/* current parser for TCP stream */
1703 	struct lro_entry *le;
1704 	struct lro_head *bucket;
1705 	struct tcphdr *th;
1706 	int tcp_data_len;
1707 	int tcp_opt_len;
1708 	int error;
1709 	uint16_t tcp_data_sum;
1710 
1711 #ifdef INET
1712 	/* Quickly decide if packet cannot be LRO'ed */
1713 	if (__predict_false(V_ipforwarding != 0))
1714 		return (TCP_LRO_CANNOT);
1715 #endif
1716 #ifdef INET6
1717 	/* Quickly decide if packet cannot be LRO'ed */
1718 	if (__predict_false(V_ip6_forwarding != 0))
1719 		return (TCP_LRO_CANNOT);
1720 #endif
1721 
1722 	/* We expect a contiguous header [eh, ip, tcp]. */
1723 	pa = tcp_lro_parser(m, &po, &pi, true);
1724 	if (__predict_false(pa == NULL))
1725 		return (TCP_LRO_NOT_SUPPORTED);
1726 
1727 	/* We don't expect any padding. */
1728 	error = tcp_lro_trim_mbuf_chain(m, pa);
1729 	if (__predict_false(error != 0))
1730 		return (error);
1731 
1732 #ifdef INET
1733 	switch (pa->data.lro_type) {
1734 	case LRO_TYPE_IPV4_TCP:
1735 		error = tcp_lro_rx_ipv4(lc, m, pa->ip4);
1736 		if (__predict_false(error != 0))
1737 			return (error);
1738 		break;
1739 	default:
1740 		break;
1741 	}
1742 #endif
1743 	/* If no hardware or arrival stamp on the packet add timestamp */
1744 	if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
1745 		m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
1746 		m->m_flags |= M_TSTMP_LRO;
1747 	}
1748 
1749 	/* Get pointer to TCP header. */
1750 	th = pa->tcp;
1751 
1752 	/* Don't process SYN packets. */
1753 	if (__predict_false(th->th_flags & TH_SYN))
1754 		return (TCP_LRO_CANNOT);
1755 
1756 	/* Get total TCP header length and compute payload length. */
1757 	tcp_opt_len = (th->th_off << 2);
1758 	tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th -
1759 	    (uint8_t *)m->m_data) - tcp_opt_len;
1760 	tcp_opt_len -= sizeof(*th);
1761 
1762 	/* Don't process invalid TCP headers. */
1763 	if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0))
1764 		return (TCP_LRO_CANNOT);
1765 
1766 	/* Compute TCP data only checksum. */
1767 	if (tcp_data_len == 0)
1768 		tcp_data_sum = 0;	/* no data, no checksum */
1769 	else if (__predict_false(csum != 0))
1770 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum);
1771 	else
1772 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum);
1773 
1774 	/* Save TCP info in mbuf. */
1775 	m->m_nextpkt = NULL;
1776 	m->m_pkthdr.rcvif = lc->ifp;
1777 	m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum;
1778 	m->m_pkthdr.lro_tcp_d_len = tcp_data_len;
1779 	m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data);
1780 	m->m_pkthdr.lro_nsegs = 1;
1781 
1782 	/* Get hash bucket. */
1783 	if (!use_hash) {
1784 		bucket = &lc->lro_hash[0];
1785 	} else {
1786 		bucket = tcp_lro_rx_get_bucket(lc, m, pa);
1787 	}
1788 
1789 	/* Try to find a matching previous segment. */
1790 	LIST_FOREACH(le, bucket, hash_next) {
1791 		/* Compare addresses and ports. */
1792 		if (lro_address_compare(&po.data, &le->outer.data) == false ||
1793 		    lro_address_compare(&pi.data, &le->inner.data) == false)
1794 			continue;
1795 
1796 		/* Check if no data and old ACK. */
1797 		if (tcp_data_len == 0 &&
1798 		    SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1799 			m_freem(m);
1800 			return (0);
1801 		}
1802 
1803 		/* Mark "m" in the last spot. */
1804 		le->m_last_mbuf->m_nextpkt = m;
1805 		/* Now set the tail to "m". */
1806 		le->m_last_mbuf = m;
1807 		return (0);
1808 	}
1809 
1810 	/* Try to find an empty slot. */
1811 	if (LIST_EMPTY(&lc->lro_free))
1812 		return (TCP_LRO_NO_ENTRIES);
1813 
1814 	/* Start a new segment chain. */
1815 	le = LIST_FIRST(&lc->lro_free);
1816 	LIST_REMOVE(le, next);
1817 	tcp_lro_active_insert(lc, bucket, le);
1818 
1819 	/* Make sure the headers are set. */
1820 	le->inner = pi;
1821 	le->outer = po;
1822 
1823 	/* Store time this entry was allocated. */
1824 	le->alloc_time = lc->lro_last_queue_time;
1825 
1826 	tcp_set_entry_to_mbuf(lc, le, m, th);
1827 
1828 	/* Now set the tail to "m". */
1829 	le->m_last_mbuf = m;
1830 
1831 	return (0);
1832 }
1833 
1834 int
1835 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
1836 {
1837 	int error;
1838 
1839 	/* get current time */
1840 	binuptime(&lc->lro_last_queue_time);
1841 
1842 	CURVNET_SET(lc->ifp->if_vnet);
1843 	error = tcp_lro_rx_common(lc, m, csum, true);
1844 	CURVNET_RESTORE();
1845 
1846 	return (error);
1847 }
1848 
1849 void
1850 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
1851 {
1852 	/* sanity checks */
1853 	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
1854 	    lc->lro_mbuf_max == 0)) {
1855 		/* packet drop */
1856 		m_freem(mb);
1857 		return;
1858 	}
1859 
1860 	/* check if packet is not LRO capable */
1861 	if (__predict_false(mb->m_pkthdr.csum_flags == 0 ||
1862 	    (lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
1863 		/* input packet to network layer */
1864 		(*lc->ifp->if_input) (lc->ifp, mb);
1865 		return;
1866 	}
1867 
1868 	/* create sequence number */
1869 	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
1870 	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
1871 	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
1872 	    ((uint64_t)lc->lro_mbuf_count);
1873 
1874 	/* enter mbuf */
1875 	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
1876 
1877 	/* flush if array is full */
1878 	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
1879 		tcp_lro_flush_all(lc);
1880 }
1881 
1882 /* end */
1883