xref: /freebsd/sys/netinet/tcp_lro.c (revision d30a1689f5b37e78ea189232a8b94a7011dc0dc8)
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 #include <net/if_dl.h>
57 #include <net/if_media.h>
58 #include <net/if_types.h>
59 #include <net/infiniband.h>
60 #include <net/if_lagg.h>
61 
62 #include <netinet/in_systm.h>
63 #include <netinet/in.h>
64 #include <netinet/ip6.h>
65 #include <netinet/ip.h>
66 #include <netinet/ip_var.h>
67 #include <netinet/in_pcb.h>
68 #include <netinet6/in6_pcb.h>
69 #include <netinet/tcp.h>
70 #include <netinet/tcp_seq.h>
71 #include <netinet/tcp_lro.h>
72 #include <netinet/tcp_var.h>
73 #include <netinet/tcpip.h>
74 #include <netinet/tcp_hpts.h>
75 #include <netinet/tcp_log_buf.h>
76 #include <netinet/udp.h>
77 #include <netinet6/ip6_var.h>
78 
79 #include <machine/in_cksum.h>
80 
81 static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures");
82 
83 #define	TCP_LRO_TS_OPTION \
84     ntohl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | \
85 	  (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)
86 
87 static void	tcp_lro_rx_done(struct lro_ctrl *lc);
88 static int	tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m,
89 		    uint32_t csum, bool use_hash);
90 
91 #ifdef TCPHPTS
92 static bool	do_bpf_strip_and_compress(struct inpcb *, struct lro_ctrl *,
93 		struct lro_entry *, struct mbuf **, struct mbuf **, struct mbuf **,
94  		bool *, bool, bool, struct ifnet *, bool);
95 
96 #endif
97 
98 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, lro,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
99     "TCP LRO");
100 
101 static long tcplro_stacks_wanting_mbufq;
102 counter_u64_t tcp_inp_lro_direct_queue;
103 counter_u64_t tcp_inp_lro_wokeup_queue;
104 counter_u64_t tcp_inp_lro_compressed;
105 counter_u64_t tcp_inp_lro_locks_taken;
106 counter_u64_t tcp_extra_mbuf;
107 counter_u64_t tcp_would_have_but;
108 counter_u64_t tcp_comp_total;
109 counter_u64_t tcp_uncomp_total;
110 counter_u64_t tcp_bad_csums;
111 
112 static unsigned	tcp_lro_entries = TCP_LRO_ENTRIES;
113 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries,
114     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0,
115     "default number of LRO entries");
116 
117 static uint32_t tcp_lro_cpu_set_thresh = TCP_LRO_CPU_DECLARATION_THRESH;
118 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, lro_cpu_threshold,
119     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_cpu_set_thresh, 0,
120     "Number of interrupts in a row on the same CPU that will make us declare an 'affinity' cpu?");
121 
122 static uint32_t tcp_less_accurate_lro_ts = 0;
123 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, lro_less_accurate,
124     CTLFLAG_MPSAFE, &tcp_less_accurate_lro_ts, 0,
125     "Do we trade off efficency by doing less timestamp operations for time accuracy?");
126 
127 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, fullqueue, CTLFLAG_RD,
128     &tcp_inp_lro_direct_queue, "Number of lro's fully queued to transport");
129 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, wokeup, CTLFLAG_RD,
130     &tcp_inp_lro_wokeup_queue, "Number of lro's where we woke up transport via hpts");
131 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, compressed, CTLFLAG_RD,
132     &tcp_inp_lro_compressed, "Number of lro's compressed and sent to transport");
133 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lockcnt, CTLFLAG_RD,
134     &tcp_inp_lro_locks_taken, "Number of lro's inp_wlocks taken");
135 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, extra_mbuf, CTLFLAG_RD,
136     &tcp_extra_mbuf, "Number of times we had an extra compressed ack dropped into the tp");
137 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, would_have_but, CTLFLAG_RD,
138     &tcp_would_have_but, "Number of times we would have had an extra compressed, but mget failed");
139 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, with_m_ackcmp, CTLFLAG_RD,
140     &tcp_comp_total, "Number of mbufs queued with M_ACKCMP flags set");
141 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, without_m_ackcmp, CTLFLAG_RD,
142     &tcp_uncomp_total, "Number of mbufs queued without M_ACKCMP");
143 SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lro_badcsum, CTLFLAG_RD,
144     &tcp_bad_csums, "Number of packets that the common code saw with bad csums");
145 
146 void
147 tcp_lro_reg_mbufq(void)
148 {
149 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, 1);
150 }
151 
152 void
153 tcp_lro_dereg_mbufq(void)
154 {
155 	atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, -1);
156 }
157 
158 static __inline void
159 tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_head *bucket,
160     struct lro_entry *le)
161 {
162 
163 	LIST_INSERT_HEAD(&lc->lro_active, le, next);
164 	LIST_INSERT_HEAD(bucket, le, hash_next);
165 }
166 
167 static __inline void
168 tcp_lro_active_remove(struct lro_entry *le)
169 {
170 
171 	LIST_REMOVE(le, next);		/* active list */
172 	LIST_REMOVE(le, hash_next);	/* hash bucket */
173 }
174 
175 int
176 tcp_lro_init(struct lro_ctrl *lc)
177 {
178 	return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0));
179 }
180 
181 int
182 tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
183     unsigned lro_entries, unsigned lro_mbufs)
184 {
185 	struct lro_entry *le;
186 	size_t size;
187 	unsigned i, elements;
188 
189 	lc->lro_bad_csum = 0;
190 	lc->lro_queued = 0;
191 	lc->lro_flushed = 0;
192 	lc->lro_mbuf_count = 0;
193 	lc->lro_mbuf_max = lro_mbufs;
194 	lc->lro_cnt = lro_entries;
195 	lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
196 	lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
197 	lc->ifp = ifp;
198 	LIST_INIT(&lc->lro_free);
199 	LIST_INIT(&lc->lro_active);
200 
201 	/* create hash table to accelerate entry lookup */
202 	if (lro_entries > lro_mbufs)
203 		elements = lro_entries;
204 	else
205 		elements = lro_mbufs;
206 	lc->lro_hash = phashinit_flags(elements, M_LRO, &lc->lro_hashsz,
207 	    HASH_NOWAIT);
208 	if (lc->lro_hash == NULL) {
209 		memset(lc, 0, sizeof(*lc));
210 		return (ENOMEM);
211 	}
212 
213 	/* compute size to allocate */
214 	size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
215 	    (lro_entries * sizeof(*le));
216 	lc->lro_mbuf_data = (struct lro_mbuf_sort *)
217 	    malloc(size, M_LRO, M_NOWAIT | M_ZERO);
218 
219 	/* check for out of memory */
220 	if (lc->lro_mbuf_data == NULL) {
221 		free(lc->lro_hash, M_LRO);
222 		memset(lc, 0, sizeof(*lc));
223 		return (ENOMEM);
224 	}
225 	/* compute offset for LRO entries */
226 	le = (struct lro_entry *)
227 	    (lc->lro_mbuf_data + lro_mbufs);
228 
229 	/* setup linked list */
230 	for (i = 0; i != lro_entries; i++)
231 		LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
232 
233 	return (0);
234 }
235 
236 struct vxlan_header {
237 	uint32_t	vxlh_flags;
238 	uint32_t	vxlh_vni;
239 };
240 
241 static inline void *
242 tcp_lro_low_level_parser(void *ptr, struct lro_parser *parser, bool update_data, bool is_vxlan, int mlen)
243 {
244 	const struct ether_vlan_header *eh;
245 	void *old;
246 	uint16_t eth_type;
247 
248 	if (update_data)
249 		memset(parser, 0, sizeof(*parser));
250 
251 	old = ptr;
252 
253 	if (is_vxlan) {
254 		const struct vxlan_header *vxh;
255 		vxh = ptr;
256 		ptr = (uint8_t *)ptr + sizeof(*vxh);
257 		if (update_data) {
258 			parser->data.vxlan_vni =
259 			    vxh->vxlh_vni & htonl(0xffffff00);
260 		}
261 	}
262 
263 	eh = ptr;
264 	if (__predict_false(eh->evl_encap_proto == htons(ETHERTYPE_VLAN))) {
265 		eth_type = eh->evl_proto;
266 		if (update_data) {
267 			/* strip priority and keep VLAN ID only */
268 			parser->data.vlan_id = eh->evl_tag & htons(EVL_VLID_MASK);
269 		}
270 		/* advance to next header */
271 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
272 		mlen -= (ETHER_HDR_LEN  + ETHER_VLAN_ENCAP_LEN);
273 	} else {
274 		eth_type = eh->evl_encap_proto;
275 		/* advance to next header */
276 		mlen -= ETHER_HDR_LEN;
277 		ptr = (uint8_t *)ptr + ETHER_HDR_LEN;
278 	}
279 	if (__predict_false(mlen <= 0))
280 		return (NULL);
281 	switch (eth_type) {
282 #ifdef INET
283 	case htons(ETHERTYPE_IP):
284 		parser->ip4 = ptr;
285 		if (__predict_false(mlen < sizeof(struct ip)))
286 			return (NULL);
287 		/* Ensure there are no IPv4 options. */
288 		if ((parser->ip4->ip_hl << 2) != sizeof (*parser->ip4))
289 			break;
290 		/* .. and the packet is not fragmented. */
291 		if (parser->ip4->ip_off & htons(IP_MF|IP_OFFMASK))
292 			break;
293 		ptr = (uint8_t *)ptr + (parser->ip4->ip_hl << 2);
294 		mlen -= sizeof(struct ip);
295 		if (update_data) {
296 			parser->data.s_addr.v4 = parser->ip4->ip_src;
297 			parser->data.d_addr.v4 = parser->ip4->ip_dst;
298 		}
299 		switch (parser->ip4->ip_p) {
300 		case IPPROTO_UDP:
301 			if (__predict_false(mlen < sizeof(struct udphdr)))
302 				return (NULL);
303 			parser->udp = ptr;
304 			if (update_data) {
305 				parser->data.lro_type = LRO_TYPE_IPV4_UDP;
306 				parser->data.s_port = parser->udp->uh_sport;
307 				parser->data.d_port = parser->udp->uh_dport;
308 			} else {
309 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_UDP);
310 			}
311 			ptr = ((uint8_t *)ptr + sizeof(*parser->udp));
312 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
313 			return (ptr);
314 		case IPPROTO_TCP:
315 			parser->tcp = ptr;
316 			if (__predict_false(mlen < sizeof(struct tcphdr)))
317 				return (NULL);
318 			if (update_data) {
319 				parser->data.lro_type = LRO_TYPE_IPV4_TCP;
320 				parser->data.s_port = parser->tcp->th_sport;
321 				parser->data.d_port = parser->tcp->th_dport;
322 			} else {
323 				MPASS(parser->data.lro_type == LRO_TYPE_IPV4_TCP);
324 			}
325 			if (__predict_false(mlen < (parser->tcp->th_off << 2)))
326 				return (NULL);
327 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
328 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
329 			return (ptr);
330 		default:
331 			break;
332 		}
333 		break;
334 #endif
335 #ifdef INET6
336 	case htons(ETHERTYPE_IPV6):
337 		parser->ip6 = ptr;
338 		if (__predict_false(mlen < sizeof(struct ip6_hdr)))
339 			return (NULL);
340 		ptr = (uint8_t *)ptr + sizeof(*parser->ip6);
341 		if (update_data) {
342 			parser->data.s_addr.v6 = parser->ip6->ip6_src;
343 			parser->data.d_addr.v6 = parser->ip6->ip6_dst;
344 		}
345 		mlen -= sizeof(struct ip6_hdr);
346 		switch (parser->ip6->ip6_nxt) {
347 		case IPPROTO_UDP:
348 			if (__predict_false(mlen < sizeof(struct udphdr)))
349 				return (NULL);
350 			parser->udp = ptr;
351 			if (update_data) {
352 				parser->data.lro_type = LRO_TYPE_IPV6_UDP;
353 				parser->data.s_port = parser->udp->uh_sport;
354 				parser->data.d_port = parser->udp->uh_dport;
355 			} else {
356 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_UDP);
357 			}
358 			ptr = (uint8_t *)ptr + sizeof(*parser->udp);
359 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
360 			return (ptr);
361 		case IPPROTO_TCP:
362 			if (__predict_false(mlen < sizeof(struct tcphdr)))
363 				return (NULL);
364 			parser->tcp = ptr;
365 			if (update_data) {
366 				parser->data.lro_type = LRO_TYPE_IPV6_TCP;
367 				parser->data.s_port = parser->tcp->th_sport;
368 				parser->data.d_port = parser->tcp->th_dport;
369 			} else {
370 				MPASS(parser->data.lro_type == LRO_TYPE_IPV6_TCP);
371 			}
372 			if (__predict_false(mlen < (parser->tcp->th_off << 2)))
373 				return (NULL);
374 			ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2);
375 			parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old;
376 			return (ptr);
377 		default:
378 			break;
379 		}
380 		break;
381 #endif
382 	default:
383 		break;
384 	}
385 	/* Invalid packet - cannot parse */
386 	return (NULL);
387 }
388 
389 static const int vxlan_csum = CSUM_INNER_L3_CALC | CSUM_INNER_L3_VALID |
390     CSUM_INNER_L4_CALC | CSUM_INNER_L4_VALID;
391 
392 static inline struct lro_parser *
393 tcp_lro_parser(struct mbuf *m, struct lro_parser *po, struct lro_parser *pi, bool update_data)
394 {
395 	void *data_ptr;
396 
397 	/* Try to parse outer headers first. */
398 	data_ptr = tcp_lro_low_level_parser(m->m_data, po, update_data, false, m->m_len);
399 	if (data_ptr == NULL || po->total_hdr_len > m->m_len)
400 		return (NULL);
401 
402 	if (update_data) {
403 		/* Store VLAN ID, if any. */
404 		if (__predict_false(m->m_flags & M_VLANTAG)) {
405 			po->data.vlan_id =
406 			    htons(m->m_pkthdr.ether_vtag) & htons(EVL_VLID_MASK);
407 		}
408 		/* Store decrypted flag, if any. */
409 		if (__predict_false((m->m_pkthdr.csum_flags &
410 		    CSUM_TLS_MASK) == CSUM_TLS_DECRYPTED))
411 			po->data.lro_flags |= LRO_FLAG_DECRYPTED;
412 	}
413 
414 	switch (po->data.lro_type) {
415 	case LRO_TYPE_IPV4_UDP:
416 	case LRO_TYPE_IPV6_UDP:
417 		/* Check for VXLAN headers. */
418 		if ((m->m_pkthdr.csum_flags & vxlan_csum) != vxlan_csum)
419 			break;
420 
421 		/* Try to parse inner headers. */
422 		data_ptr = tcp_lro_low_level_parser(data_ptr, pi, update_data, true,
423 						    (m->m_len - ((caddr_t)data_ptr - m->m_data)));
424 		if (data_ptr == NULL || (pi->total_hdr_len + po->total_hdr_len) > m->m_len)
425 			break;
426 
427 		/* Verify supported header types. */
428 		switch (pi->data.lro_type) {
429 		case LRO_TYPE_IPV4_TCP:
430 		case LRO_TYPE_IPV6_TCP:
431 			return (pi);
432 		default:
433 			break;
434 		}
435 		break;
436 	case LRO_TYPE_IPV4_TCP:
437 	case LRO_TYPE_IPV6_TCP:
438 		if (update_data)
439 			memset(pi, 0, sizeof(*pi));
440 		return (po);
441 	default:
442 		break;
443 	}
444 	return (NULL);
445 }
446 
447 static inline int
448 tcp_lro_trim_mbuf_chain(struct mbuf *m, const struct lro_parser *po)
449 {
450 	int len;
451 
452 	switch (po->data.lro_type) {
453 #ifdef INET
454 	case LRO_TYPE_IPV4_TCP:
455 		len = ((uint8_t *)po->ip4 - (uint8_t *)m->m_data) +
456 		    ntohs(po->ip4->ip_len);
457 		break;
458 #endif
459 #ifdef INET6
460 	case LRO_TYPE_IPV6_TCP:
461 		len = ((uint8_t *)po->ip6 - (uint8_t *)m->m_data) +
462 		    ntohs(po->ip6->ip6_plen) + sizeof(*po->ip6);
463 		break;
464 #endif
465 	default:
466 		return (TCP_LRO_CANNOT);
467 	}
468 
469 	/*
470 	 * If the frame is padded beyond the end of the IP packet,
471 	 * then trim the extra bytes off:
472 	 */
473 	if (__predict_true(m->m_pkthdr.len == len)) {
474 		return (0);
475 	} else if (m->m_pkthdr.len > len) {
476 		m_adj(m, len - m->m_pkthdr.len);
477 		return (0);
478 	}
479 	return (TCP_LRO_CANNOT);
480 }
481 
482 static struct tcphdr *
483 tcp_lro_get_th(struct mbuf *m)
484 {
485 	return ((struct tcphdr *)((uint8_t *)m->m_data + m->m_pkthdr.lro_tcp_h_off));
486 }
487 
488 static void
489 lro_free_mbuf_chain(struct mbuf *m)
490 {
491 	struct mbuf *save;
492 
493 	while (m) {
494 		save = m->m_nextpkt;
495 		m->m_nextpkt = NULL;
496 		m_freem(m);
497 		m = save;
498 	}
499 }
500 
501 void
502 tcp_lro_free(struct lro_ctrl *lc)
503 {
504 	struct lro_entry *le;
505 	unsigned x;
506 
507 	/* reset LRO free list */
508 	LIST_INIT(&lc->lro_free);
509 
510 	/* free active mbufs, if any */
511 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
512 		tcp_lro_active_remove(le);
513 		lro_free_mbuf_chain(le->m_head);
514 	}
515 
516 	/* free hash table */
517 	free(lc->lro_hash, M_LRO);
518 	lc->lro_hash = NULL;
519 	lc->lro_hashsz = 0;
520 
521 	/* free mbuf array, if any */
522 	for (x = 0; x != lc->lro_mbuf_count; x++)
523 		m_freem(lc->lro_mbuf_data[x].mb);
524 	lc->lro_mbuf_count = 0;
525 
526 	/* free allocated memory, if any */
527 	free(lc->lro_mbuf_data, M_LRO);
528 	lc->lro_mbuf_data = NULL;
529 }
530 
531 static uint16_t
532 tcp_lro_rx_csum_tcphdr(const struct tcphdr *th)
533 {
534 	const uint16_t *ptr;
535 	uint32_t csum;
536 	uint16_t len;
537 
538 	csum = -th->th_sum;	/* exclude checksum field */
539 	len = th->th_off;
540 	ptr = (const uint16_t *)th;
541 	while (len--) {
542 		csum += *ptr;
543 		ptr++;
544 		csum += *ptr;
545 		ptr++;
546 	}
547 	while (csum > 0xffff)
548 		csum = (csum >> 16) + (csum & 0xffff);
549 
550 	return (csum);
551 }
552 
553 static uint16_t
554 tcp_lro_rx_csum_data(const struct lro_parser *pa, uint16_t tcp_csum)
555 {
556 	uint32_t c;
557 	uint16_t cs;
558 
559 	c = tcp_csum;
560 
561 	switch (pa->data.lro_type) {
562 #ifdef INET6
563 	case LRO_TYPE_IPV6_TCP:
564 		/* Compute full pseudo IPv6 header checksum. */
565 		cs = in6_cksum_pseudo(pa->ip6, ntohs(pa->ip6->ip6_plen), pa->ip6->ip6_nxt, 0);
566 		break;
567 #endif
568 #ifdef INET
569 	case LRO_TYPE_IPV4_TCP:
570 		/* Compute full pseudo IPv4 header checsum. */
571 		cs = in_addword(ntohs(pa->ip4->ip_len) - sizeof(*pa->ip4), IPPROTO_TCP);
572 		cs = in_pseudo(pa->ip4->ip_src.s_addr, pa->ip4->ip_dst.s_addr, htons(cs));
573 		break;
574 #endif
575 	default:
576 		cs = 0;		/* Keep compiler happy. */
577 		break;
578 	}
579 
580 	/* Complement checksum. */
581 	cs = ~cs;
582 	c += cs;
583 
584 	/* Remove TCP header checksum. */
585 	cs = ~tcp_lro_rx_csum_tcphdr(pa->tcp);
586 	c += cs;
587 
588 	/* Compute checksum remainder. */
589 	while (c > 0xffff)
590 		c = (c >> 16) + (c & 0xffff);
591 
592 	return (c);
593 }
594 
595 static void
596 tcp_lro_rx_done(struct lro_ctrl *lc)
597 {
598 	struct lro_entry *le;
599 
600 	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
601 		tcp_lro_active_remove(le);
602 		tcp_lro_flush(lc, le);
603 	}
604 }
605 
606 static void
607 tcp_lro_flush_active(struct lro_ctrl *lc)
608 {
609 	struct lro_entry *le;
610 
611 	/*
612 	 * Walk through the list of le entries, and
613 	 * any one that does have packets flush. This
614 	 * is called because we have an inbound packet
615 	 * (e.g. SYN) that has to have all others flushed
616 	 * in front of it. Note we have to do the remove
617 	 * because tcp_lro_flush() assumes that the entry
618 	 * is being freed. This is ok it will just get
619 	 * reallocated again like it was new.
620 	 */
621 	LIST_FOREACH(le, &lc->lro_active, next) {
622 		if (le->m_head != NULL) {
623 			tcp_lro_active_remove(le);
624 			tcp_lro_flush(lc, le);
625 		}
626 	}
627 }
628 
629 void
630 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
631 {
632 	struct lro_entry *le, *le_tmp;
633 	uint64_t now, tov;
634 	struct bintime bt;
635 
636 	NET_EPOCH_ASSERT();
637 	if (LIST_EMPTY(&lc->lro_active))
638 		return;
639 
640 	/* get timeout time and current time in ns */
641 	binuptime(&bt);
642 	now = bintime2ns(&bt);
643 	tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000));
644 	LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
645 		if (now >= (bintime2ns(&le->alloc_time) + tov)) {
646 			tcp_lro_active_remove(le);
647 			tcp_lro_flush(lc, le);
648 		}
649 	}
650 }
651 
652 #ifdef INET
653 static int
654 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4)
655 {
656 	uint16_t csum;
657 
658 	/* Legacy IP has a header checksum that needs to be correct. */
659 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
660 		if (__predict_false((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0)) {
661 			lc->lro_bad_csum++;
662 			return (TCP_LRO_CANNOT);
663 		}
664 	} else {
665 		csum = in_cksum_hdr(ip4);
666 		if (__predict_false(csum != 0)) {
667 			lc->lro_bad_csum++;
668 			return (TCP_LRO_CANNOT);
669 		}
670 	}
671 	return (0);
672 }
673 #endif
674 
675 #ifdef TCPHPTS
676 static void
677 tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
678     const struct lro_entry *le, const struct mbuf *m,
679     int frm, int32_t tcp_data_len, uint32_t th_seq,
680     uint32_t th_ack, uint16_t th_win)
681 {
682 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
683 		union tcp_log_stackspecific log;
684 		struct timeval tv, btv;
685 		uint32_t cts;
686 
687 		cts = tcp_get_usecs(&tv);
688 		memset(&log, 0, sizeof(union tcp_log_stackspecific));
689 		log.u_bbr.flex8 = frm;
690 		log.u_bbr.flex1 = tcp_data_len;
691 		if (m)
692 			log.u_bbr.flex2 = m->m_pkthdr.len;
693 		else
694 			log.u_bbr.flex2 = 0;
695 		if (le->m_head) {
696 			log.u_bbr.flex3 = le->m_head->m_pkthdr.lro_nsegs;
697 			log.u_bbr.flex4 = le->m_head->m_pkthdr.lro_tcp_d_len;
698 			log.u_bbr.flex5 = le->m_head->m_pkthdr.len;
699 			log.u_bbr.delRate = le->m_head->m_flags;
700 			log.u_bbr.rttProp = le->m_head->m_pkthdr.rcv_tstmp;
701 		}
702 		log.u_bbr.inflight = th_seq;
703 		log.u_bbr.delivered = th_ack;
704 		log.u_bbr.timeStamp = cts;
705 		log.u_bbr.epoch = le->next_seq;
706 		log.u_bbr.lt_epoch = le->ack_seq;
707 		log.u_bbr.pacing_gain = th_win;
708 		log.u_bbr.cwnd_gain = le->window;
709 		log.u_bbr.lost = curcpu;
710 		log.u_bbr.cur_del_rate = (uintptr_t)m;
711 		log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
712 		bintime2timeval(&lc->lro_last_queue_time, &btv);
713 		log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
714 		log.u_bbr.flex7 = le->compressed;
715 		log.u_bbr.pacing_gain = le->uncompressed;
716 		if (in_epoch(net_epoch_preempt))
717 			log.u_bbr.inhpts = 1;
718 		else
719 			log.u_bbr.inhpts = 0;
720 		TCP_LOG_EVENTP(tp, NULL,
721 			       &tp->t_inpcb->inp_socket->so_rcv,
722 			       &tp->t_inpcb->inp_socket->so_snd,
723 			       TCP_LOG_LRO, 0,
724 			       0, &log, false, &tv);
725 	}
726 }
727 #endif
728 
729 static inline void
730 tcp_lro_assign_and_checksum_16(uint16_t *ptr, uint16_t value, uint16_t *psum)
731 {
732 	uint32_t csum;
733 
734 	csum = 0xffff - *ptr + value;
735 	while (csum > 0xffff)
736 		csum = (csum >> 16) + (csum & 0xffff);
737 	*ptr = value;
738 	*psum = csum;
739 }
740 
741 static uint16_t
742 tcp_lro_update_checksum(const struct lro_parser *pa, const struct lro_entry *le,
743     uint16_t payload_len, uint16_t delta_sum)
744 {
745 	uint32_t csum;
746 	uint16_t tlen;
747 	uint16_t temp[5] = {};
748 
749 	switch (pa->data.lro_type) {
750 	case LRO_TYPE_IPV4_TCP:
751 		/* Compute new IPv4 length. */
752 		tlen = (pa->ip4->ip_hl << 2) + (pa->tcp->th_off << 2) + payload_len;
753 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
754 
755 		/* Subtract delta from current IPv4 checksum. */
756 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
757 		while (csum > 0xffff)
758 			csum = (csum >> 16) + (csum & 0xffff);
759 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
760 		goto update_tcp_header;
761 
762 	case LRO_TYPE_IPV6_TCP:
763 		/* Compute new IPv6 length. */
764 		tlen = (pa->tcp->th_off << 2) + payload_len;
765 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
766 		goto update_tcp_header;
767 
768 	case LRO_TYPE_IPV4_UDP:
769 		/* Compute new IPv4 length. */
770 		tlen = (pa->ip4->ip_hl << 2) + sizeof(*pa->udp) + payload_len;
771 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]);
772 
773 		/* Subtract delta from current IPv4 checksum. */
774 		csum = pa->ip4->ip_sum + 0xffff - temp[0];
775 		while (csum > 0xffff)
776 			csum = (csum >> 16) + (csum & 0xffff);
777 		tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]);
778 		goto update_udp_header;
779 
780 	case LRO_TYPE_IPV6_UDP:
781 		/* Compute new IPv6 length. */
782 		tlen = sizeof(*pa->udp) + payload_len;
783 		tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]);
784 		goto update_udp_header;
785 
786 	default:
787 		return (0);
788 	}
789 
790 update_tcp_header:
791 	/* Compute current TCP header checksum. */
792 	temp[2] = tcp_lro_rx_csum_tcphdr(pa->tcp);
793 
794 	/* Incorporate the latest ACK into the TCP header. */
795 	pa->tcp->th_ack = le->ack_seq;
796 	pa->tcp->th_win = le->window;
797 
798 	/* Incorporate latest timestamp into the TCP header. */
799 	if (le->timestamp != 0) {
800 		uint32_t *ts_ptr;
801 
802 		ts_ptr = (uint32_t *)(pa->tcp + 1);
803 		ts_ptr[1] = htonl(le->tsval);
804 		ts_ptr[2] = le->tsecr;
805 	}
806 
807 	/* Compute new TCP header checksum. */
808 	temp[3] = tcp_lro_rx_csum_tcphdr(pa->tcp);
809 
810 	/* Compute new TCP checksum. */
811 	csum = pa->tcp->th_sum + 0xffff - delta_sum +
812 	    0xffff - temp[0] + 0xffff - temp[3] + temp[2];
813 	while (csum > 0xffff)
814 		csum = (csum >> 16) + (csum & 0xffff);
815 
816 	/* Assign new TCP checksum. */
817 	tcp_lro_assign_and_checksum_16(&pa->tcp->th_sum, csum, &temp[4]);
818 
819 	/* Compute all modififications affecting next checksum. */
820 	csum = temp[0] + temp[1] + 0xffff - temp[2] +
821 	    temp[3] + temp[4] + delta_sum;
822 	while (csum > 0xffff)
823 		csum = (csum >> 16) + (csum & 0xffff);
824 
825 	/* Return delta checksum to next stage, if any. */
826 	return (csum);
827 
828 update_udp_header:
829 	tlen = sizeof(*pa->udp) + payload_len;
830 	/* Assign new UDP length and compute checksum delta. */
831 	tcp_lro_assign_and_checksum_16(&pa->udp->uh_ulen, htons(tlen), &temp[2]);
832 
833 	/* Check if there is a UDP checksum. */
834 	if (__predict_false(pa->udp->uh_sum != 0)) {
835 		/* Compute new UDP checksum. */
836 		csum = pa->udp->uh_sum + 0xffff - delta_sum +
837 		    0xffff - temp[0] + 0xffff - temp[2];
838 		while (csum > 0xffff)
839 			csum = (csum >> 16) + (csum & 0xffff);
840 		/* Assign new UDP checksum. */
841 		tcp_lro_assign_and_checksum_16(&pa->udp->uh_sum, csum, &temp[3]);
842 	}
843 
844 	/* Compute all modififications affecting next checksum. */
845 	csum = temp[0] + temp[1] + temp[2] + temp[3] + delta_sum;
846 	while (csum > 0xffff)
847 		csum = (csum >> 16) + (csum & 0xffff);
848 
849 	/* Return delta checksum to next stage, if any. */
850 	return (csum);
851 }
852 
853 static void
854 tcp_flush_out_entry(struct lro_ctrl *lc, struct lro_entry *le)
855 {
856 	/* Check if we need to recompute any checksums. */
857 	if (le->needs_merge) {
858 		uint16_t csum;
859 
860 		switch (le->inner.data.lro_type) {
861 		case LRO_TYPE_IPV4_TCP:
862 			csum = tcp_lro_update_checksum(&le->inner, le,
863 			    le->m_head->m_pkthdr.lro_tcp_d_len,
864 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
865 			csum = tcp_lro_update_checksum(&le->outer, NULL,
866 			    le->m_head->m_pkthdr.lro_tcp_d_len +
867 			    le->inner.total_hdr_len, csum);
868 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
869 			    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
870 			le->m_head->m_pkthdr.csum_data = 0xffff;
871 			if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
872 				le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
873 			break;
874 		case LRO_TYPE_IPV6_TCP:
875 			csum = tcp_lro_update_checksum(&le->inner, le,
876 			    le->m_head->m_pkthdr.lro_tcp_d_len,
877 			    le->m_head->m_pkthdr.lro_tcp_d_csum);
878 			csum = tcp_lro_update_checksum(&le->outer, NULL,
879 			    le->m_head->m_pkthdr.lro_tcp_d_len +
880 			    le->inner.total_hdr_len, csum);
881 			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
882 			    CSUM_PSEUDO_HDR;
883 			le->m_head->m_pkthdr.csum_data = 0xffff;
884 			if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
885 				le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
886 			break;
887 		case LRO_TYPE_NONE:
888 			switch (le->outer.data.lro_type) {
889 			case LRO_TYPE_IPV4_TCP:
890 				csum = tcp_lro_update_checksum(&le->outer, le,
891 				    le->m_head->m_pkthdr.lro_tcp_d_len,
892 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
893 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
894 				    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
895 				le->m_head->m_pkthdr.csum_data = 0xffff;
896 				if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
897 					le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
898 				break;
899 			case LRO_TYPE_IPV6_TCP:
900 				csum = tcp_lro_update_checksum(&le->outer, le,
901 				    le->m_head->m_pkthdr.lro_tcp_d_len,
902 				    le->m_head->m_pkthdr.lro_tcp_d_csum);
903 				le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
904 				    CSUM_PSEUDO_HDR;
905 				le->m_head->m_pkthdr.csum_data = 0xffff;
906 				if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED))
907 					le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED;
908 				break;
909 			default:
910 				break;
911 			}
912 			break;
913 		default:
914 			break;
915 		}
916 	}
917 
918 	/*
919 	 * Break any chain, this is not set to NULL on the singleton
920 	 * case m_nextpkt points to m_head. Other case set them
921 	 * m_nextpkt to NULL in push_and_replace.
922 	 */
923 	le->m_head->m_nextpkt = NULL;
924 	lc->lro_queued += le->m_head->m_pkthdr.lro_nsegs;
925 	(*lc->ifp->if_input)(lc->ifp, le->m_head);
926 }
927 
928 static void
929 tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le,
930     struct mbuf *m, struct tcphdr *th)
931 {
932 	uint32_t *ts_ptr;
933 	uint16_t tcp_data_len;
934 	uint16_t tcp_opt_len;
935 
936 	ts_ptr = (uint32_t *)(th + 1);
937 	tcp_opt_len = (th->th_off << 2);
938 	tcp_opt_len -= sizeof(*th);
939 
940 	/* Check if there is a timestamp option. */
941 	if (tcp_opt_len == 0 ||
942 	    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
943 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
944 		/* We failed to find the timestamp option. */
945 		le->timestamp = 0;
946 	} else {
947 		le->timestamp = 1;
948 		le->tsval = ntohl(*(ts_ptr + 1));
949 		le->tsecr = *(ts_ptr + 2);
950 	}
951 
952 	tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
953 
954 	/* Pull out TCP sequence numbers and window size. */
955 	le->next_seq = ntohl(th->th_seq) + tcp_data_len;
956 	le->ack_seq = th->th_ack;
957 	le->window = th->th_win;
958 	le->flags = tcp_get_flags(th);
959 	le->needs_merge = 0;
960 
961 	/* Setup new data pointers. */
962 	le->m_head = m;
963 	le->m_tail = m_last(m);
964 }
965 
966 static void
967 tcp_push_and_replace(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m)
968 {
969 	struct lro_parser *pa;
970 
971 	/*
972 	 * Push up the stack of the current entry
973 	 * and replace it with "m".
974 	 */
975 	struct mbuf *msave;
976 
977 	/* Grab off the next and save it */
978 	msave = le->m_head->m_nextpkt;
979 	le->m_head->m_nextpkt = NULL;
980 
981 	/* Now push out the old entry */
982 	tcp_flush_out_entry(lc, le);
983 
984 	/* Re-parse new header, should not fail. */
985 	pa = tcp_lro_parser(m, &le->outer, &le->inner, false);
986 	KASSERT(pa != NULL,
987 	    ("tcp_push_and_replace: LRO parser failed on m=%p\n", m));
988 
989 	/*
990 	 * Now to replace the data properly in the entry
991 	 * we have to reset the TCP header and
992 	 * other fields.
993 	 */
994 	tcp_set_entry_to_mbuf(lc, le, m, pa->tcp);
995 
996 	/* Restore the next list */
997 	m->m_nextpkt = msave;
998 }
999 
1000 static void
1001 tcp_lro_mbuf_append_pkthdr(struct lro_entry *le, const struct mbuf *p)
1002 {
1003 	struct mbuf *m;
1004 	uint32_t csum;
1005 
1006 	m = le->m_head;
1007 	if (m->m_pkthdr.lro_nsegs == 1) {
1008 		/* Compute relative checksum. */
1009 		csum = p->m_pkthdr.lro_tcp_d_csum;
1010 	} else {
1011 		/* Merge TCP data checksums. */
1012 		csum = (uint32_t)m->m_pkthdr.lro_tcp_d_csum +
1013 		    (uint32_t)p->m_pkthdr.lro_tcp_d_csum;
1014 		while (csum > 0xffff)
1015 			csum = (csum >> 16) + (csum & 0xffff);
1016 	}
1017 
1018 	/* Update various counters. */
1019 	m->m_pkthdr.len += p->m_pkthdr.lro_tcp_d_len;
1020 	m->m_pkthdr.lro_tcp_d_csum = csum;
1021 	m->m_pkthdr.lro_tcp_d_len += p->m_pkthdr.lro_tcp_d_len;
1022 	m->m_pkthdr.lro_nsegs += p->m_pkthdr.lro_nsegs;
1023 	le->needs_merge = 1;
1024 }
1025 
1026 static void
1027 tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le)
1028 {
1029 	/*
1030 	 * Walk through the mbuf chain we
1031 	 * have on tap and compress/condense
1032 	 * as required.
1033 	 */
1034 	uint32_t *ts_ptr;
1035 	struct mbuf *m;
1036 	struct tcphdr *th;
1037 	uint32_t tcp_data_len_total;
1038 	uint32_t tcp_data_seg_total;
1039 	uint16_t tcp_data_len;
1040 	uint16_t tcp_opt_len;
1041 
1042 	/*
1043 	 * First we must check the lead (m_head)
1044 	 * we must make sure that it is *not*
1045 	 * something that should be sent up
1046 	 * right away (sack etc).
1047 	 */
1048 again:
1049 	m = le->m_head->m_nextpkt;
1050 	if (m == NULL) {
1051 		/* Just one left. */
1052 		return;
1053 	}
1054 
1055 	th = tcp_lro_get_th(m);
1056 	tcp_opt_len = (th->th_off << 2);
1057 	tcp_opt_len -= sizeof(*th);
1058 	ts_ptr = (uint32_t *)(th + 1);
1059 
1060 	if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1061 	    *ts_ptr != TCP_LRO_TS_OPTION)) {
1062 		/*
1063 		 * Its not the timestamp. We can't
1064 		 * use this guy as the head.
1065 		 */
1066 		le->m_head->m_nextpkt = m->m_nextpkt;
1067 		tcp_push_and_replace(lc, le, m);
1068 		goto again;
1069 	}
1070 	if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH)) != 0) {
1071 		/*
1072 		 * Make sure that previously seen segments/ACKs are delivered
1073 		 * before this segment, e.g. FIN.
1074 		 */
1075 		le->m_head->m_nextpkt = m->m_nextpkt;
1076 		tcp_push_and_replace(lc, le, m);
1077 		goto again;
1078 	}
1079 	while((m = le->m_head->m_nextpkt) != NULL) {
1080 		/*
1081 		 * condense m into le, first
1082 		 * pull m out of the list.
1083 		 */
1084 		le->m_head->m_nextpkt = m->m_nextpkt;
1085 		m->m_nextpkt = NULL;
1086 		/* Setup my data */
1087 		tcp_data_len = m->m_pkthdr.lro_tcp_d_len;
1088 		th = tcp_lro_get_th(m);
1089 		ts_ptr = (uint32_t *)(th + 1);
1090 		tcp_opt_len = (th->th_off << 2);
1091 		tcp_opt_len -= sizeof(*th);
1092 		tcp_data_len_total = le->m_head->m_pkthdr.lro_tcp_d_len + tcp_data_len;
1093 		tcp_data_seg_total = le->m_head->m_pkthdr.lro_nsegs + m->m_pkthdr.lro_nsegs;
1094 
1095 		if (tcp_data_seg_total >= lc->lro_ackcnt_lim ||
1096 		    tcp_data_len_total >= lc->lro_length_lim) {
1097 			/* Flush now if appending will result in overflow. */
1098 			tcp_push_and_replace(lc, le, m);
1099 			goto again;
1100 		}
1101 		if (tcp_opt_len != 0 &&
1102 		    __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA ||
1103 		    *ts_ptr != TCP_LRO_TS_OPTION)) {
1104 			/*
1105 			 * Maybe a sack in the new one? We need to
1106 			 * start all over after flushing the
1107 			 * current le. We will go up to the beginning
1108 			 * and flush it (calling the replace again possibly
1109 			 * or just returning).
1110 			 */
1111 			tcp_push_and_replace(lc, le, m);
1112 			goto again;
1113 		}
1114 		if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH)) != 0) {
1115 			tcp_push_and_replace(lc, le, m);
1116 			goto again;
1117 		}
1118 		if (tcp_opt_len != 0) {
1119 			uint32_t tsval = ntohl(*(ts_ptr + 1));
1120 			/* Make sure timestamp values are increasing. */
1121 			if (TSTMP_GT(le->tsval, tsval))  {
1122 				tcp_push_and_replace(lc, le, m);
1123 				goto again;
1124 			}
1125 			le->tsval = tsval;
1126 			le->tsecr = *(ts_ptr + 2);
1127 		}
1128 		/* Try to append the new segment. */
1129 		if (__predict_false(ntohl(th->th_seq) != le->next_seq ||
1130 				    ((tcp_get_flags(th) & TH_ACK) !=
1131 				      (le->flags & TH_ACK)) ||
1132 				    (tcp_data_len == 0 &&
1133 				     le->ack_seq == th->th_ack &&
1134 				     le->window == th->th_win))) {
1135 			/* Out of order packet, non-ACK + ACK or dup ACK. */
1136 			tcp_push_and_replace(lc, le, m);
1137 			goto again;
1138 		}
1139 		if (tcp_data_len != 0 ||
1140 		    SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1141 			le->next_seq += tcp_data_len;
1142 			le->ack_seq = th->th_ack;
1143 			le->window = th->th_win;
1144 			le->needs_merge = 1;
1145 		} else if (th->th_ack == le->ack_seq) {
1146 			if (WIN_GT(th->th_win, le->window)) {
1147 				le->window = th->th_win;
1148 				le->needs_merge = 1;
1149 			}
1150 		}
1151 
1152 		if (tcp_data_len == 0) {
1153 			m_freem(m);
1154 			continue;
1155 		}
1156 
1157 		/* Merge TCP data checksum and length to head mbuf. */
1158 		tcp_lro_mbuf_append_pkthdr(le, m);
1159 
1160 		/*
1161 		 * Adjust the mbuf so that m_data points to the first byte of
1162 		 * the ULP payload.  Adjust the mbuf to avoid complications and
1163 		 * append new segment to existing mbuf chain.
1164 		 */
1165 		m_adj(m, m->m_pkthdr.len - tcp_data_len);
1166 		m_demote_pkthdr(m);
1167 		le->m_tail->m_next = m;
1168 		le->m_tail = m_last(m);
1169 	}
1170 }
1171 
1172 #ifdef TCPHPTS
1173 static void
1174 tcp_queue_pkts(struct inpcb *inp, struct tcpcb *tp, struct lro_entry *le)
1175 {
1176 	INP_WLOCK_ASSERT(inp);
1177 	if (tp->t_in_pkt == NULL) {
1178 		/* Nothing yet there */
1179 		tp->t_in_pkt = le->m_head;
1180 		tp->t_tail_pkt = le->m_last_mbuf;
1181 	} else {
1182 		/* Already some there */
1183 		tp->t_tail_pkt->m_nextpkt = le->m_head;
1184 		tp->t_tail_pkt = le->m_last_mbuf;
1185 	}
1186 	le->m_head = NULL;
1187 	le->m_last_mbuf = NULL;
1188 }
1189 
1190 static struct mbuf *
1191 tcp_lro_get_last_if_ackcmp(struct lro_ctrl *lc, struct lro_entry *le,
1192     struct inpcb *inp, int32_t *new_m, bool can_append_old_cmp)
1193 {
1194 	struct tcpcb *tp;
1195 	struct mbuf *m;
1196 
1197 	tp = intotcpcb(inp);
1198 	if (__predict_false(tp == NULL))
1199 		return (NULL);
1200 
1201 	/* Look at the last mbuf if any in queue */
1202  	if (can_append_old_cmp) {
1203 		m = tp->t_tail_pkt;
1204 		if (m != NULL && (m->m_flags & M_ACKCMP) != 0) {
1205 			if (M_TRAILINGSPACE(m) >= sizeof(struct tcp_ackent)) {
1206 				tcp_lro_log(tp, lc, le, NULL, 23, 0, 0, 0, 0);
1207 				*new_m = 0;
1208 				counter_u64_add(tcp_extra_mbuf, 1);
1209 				return (m);
1210 			} else {
1211 				/* Mark we ran out of space */
1212 				inp->inp_flags2 |= INP_MBUF_L_ACKS;
1213 			}
1214 		}
1215 	}
1216 	/* Decide mbuf size. */
1217 	tcp_lro_log(tp, lc, le, NULL, 21, 0, 0, 0, 0);
1218 	if (inp->inp_flags2 & INP_MBUF_L_ACKS)
1219 		m = m_getcl(M_NOWAIT, MT_DATA, M_ACKCMP | M_PKTHDR);
1220 	else
1221 		m = m_gethdr(M_NOWAIT, MT_DATA);
1222 
1223 	if (__predict_false(m == NULL)) {
1224 		counter_u64_add(tcp_would_have_but, 1);
1225 		return (NULL);
1226 	}
1227 	counter_u64_add(tcp_comp_total, 1);
1228  	m->m_pkthdr.rcvif = lc->ifp;
1229 	m->m_flags |= M_ACKCMP;
1230 	*new_m = 1;
1231 	return (m);
1232 }
1233 
1234 static struct inpcb *
1235 tcp_lro_lookup(struct ifnet *ifp, struct lro_parser *pa)
1236 {
1237 	struct inpcb *inp;
1238 
1239 	switch (pa->data.lro_type) {
1240 #ifdef INET6
1241 	case LRO_TYPE_IPV6_TCP:
1242 		inp = in6_pcblookup(&V_tcbinfo,
1243 		    &pa->data.s_addr.v6,
1244 		    pa->data.s_port,
1245 		    &pa->data.d_addr.v6,
1246 		    pa->data.d_port,
1247 		    INPLOOKUP_WLOCKPCB,
1248 		    ifp);
1249 		break;
1250 #endif
1251 #ifdef INET
1252 	case LRO_TYPE_IPV4_TCP:
1253 		inp = in_pcblookup(&V_tcbinfo,
1254 		    pa->data.s_addr.v4,
1255 		    pa->data.s_port,
1256 		    pa->data.d_addr.v4,
1257 		    pa->data.d_port,
1258 		    INPLOOKUP_WLOCKPCB,
1259 		    ifp);
1260 		break;
1261 #endif
1262 	default:
1263 		inp = NULL;
1264 		break;
1265 	}
1266 	return (inp);
1267 }
1268 
1269 static inline bool
1270 tcp_lro_ack_valid(struct mbuf *m, struct tcphdr *th, uint32_t **ppts, bool *other_opts)
1271 {
1272 	/*
1273 	 * This function returns two bits of valuable information.
1274 	 * a) Is what is present capable of being ack-compressed,
1275 	 *    we can ack-compress if there is no options or just
1276 	 *    a timestamp option, and of course the th_flags must
1277 	 *    be correct as well.
1278 	 * b) Our other options present such as SACK. This is
1279 	 *    used to determine if we want to wakeup or not.
1280 	 */
1281 	bool ret = true;
1282 
1283 	switch (th->th_off << 2) {
1284 	case (sizeof(*th) + TCPOLEN_TSTAMP_APPA):
1285 		*ppts = (uint32_t *)(th + 1);
1286 		/* Check if we have only one timestamp option. */
1287 		if (**ppts == TCP_LRO_TS_OPTION)
1288 			*other_opts = false;
1289 		else {
1290 			*other_opts = true;
1291 			ret = false;
1292 		}
1293 		break;
1294 	case (sizeof(*th)):
1295 		/* No options. */
1296 		*ppts = NULL;
1297 		*other_opts = false;
1298 		break;
1299 	default:
1300 		*ppts = NULL;
1301 		*other_opts = true;
1302 		ret = false;
1303 		break;
1304 	}
1305 	/* For ACKCMP we only accept ACK, PUSH, ECE and CWR. */
1306 	if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH | TH_ECE | TH_CWR)) != 0)
1307 		ret = false;
1308 	/* If it has data on it we cannot compress it */
1309 	if (m->m_pkthdr.lro_tcp_d_len)
1310 		ret = false;
1311 
1312 	/* ACK flag must be set. */
1313 	if (!(tcp_get_flags(th) & TH_ACK))
1314 		ret = false;
1315 	return (ret);
1316 }
1317 
1318 static int
1319 tcp_lro_flush_tcphpts(struct lro_ctrl *lc, struct lro_entry *le)
1320 {
1321 	struct inpcb *inp;
1322 	struct tcpcb *tp;
1323 	struct mbuf **pp, *cmp, *mv_to;
1324 	struct ifnet *lagg_ifp;
1325  	bool bpf_req, lagg_bpf_req, should_wake, can_append_old_cmp;
1326 
1327 	/* Check if packet doesn't belongs to our network interface. */
1328 	if ((tcplro_stacks_wanting_mbufq == 0) ||
1329 	    (le->outer.data.vlan_id != 0) ||
1330 	    (le->inner.data.lro_type != LRO_TYPE_NONE))
1331 		return (TCP_LRO_CANNOT);
1332 
1333 #ifdef INET6
1334 	/*
1335 	 * Be proactive about unspecified IPv6 address in source. As
1336 	 * we use all-zero to indicate unbounded/unconnected pcb,
1337 	 * unspecified IPv6 address can be used to confuse us.
1338 	 *
1339 	 * Note that packets with unspecified IPv6 destination is
1340 	 * already dropped in ip6_input.
1341 	 */
1342 	if (__predict_false(le->outer.data.lro_type == LRO_TYPE_IPV6_TCP &&
1343 	    IN6_IS_ADDR_UNSPECIFIED(&le->outer.data.s_addr.v6)))
1344 		return (TCP_LRO_CANNOT);
1345 
1346 	if (__predict_false(le->inner.data.lro_type == LRO_TYPE_IPV6_TCP &&
1347 	    IN6_IS_ADDR_UNSPECIFIED(&le->inner.data.s_addr.v6)))
1348 		return (TCP_LRO_CANNOT);
1349 #endif
1350 	/* Lookup inp, if any. */
1351 	inp = tcp_lro_lookup(lc->ifp,
1352 	    (le->inner.data.lro_type == LRO_TYPE_NONE) ? &le->outer : &le->inner);
1353 	if (inp == NULL)
1354 		return (TCP_LRO_CANNOT);
1355 
1356 	counter_u64_add(tcp_inp_lro_locks_taken, 1);
1357 
1358 	/* Get TCP control structure. */
1359 	tp = intotcpcb(inp);
1360 
1361 	/* Check if the inp is dead, Jim. */
1362 	if (tp == NULL ||
1363 	    (inp->inp_flags & (INP_DROPPED | INP_TIMEWAIT))) {
1364 		INP_WUNLOCK(inp);
1365 		return (TCP_LRO_CANNOT);
1366 	}
1367 	if ((inp->inp_irq_cpu_set == 0)  && (lc->lro_cpu_is_set == 1)) {
1368 		inp->inp_irq_cpu = lc->lro_last_cpu;
1369 		inp->inp_irq_cpu_set = 1;
1370 	}
1371 	/* Check if the transport doesn't support the needed optimizations. */
1372 	if ((inp->inp_flags2 & (INP_SUPPORTS_MBUFQ | INP_MBUF_ACKCMP)) == 0) {
1373 		INP_WUNLOCK(inp);
1374 		return (TCP_LRO_CANNOT);
1375 	}
1376 
1377 	if (inp->inp_flags2 & INP_MBUF_QUEUE_READY)
1378 		should_wake = false;
1379 	else
1380 		should_wake = true;
1381 	/* Check if packets should be tapped to BPF. */
1382 	bpf_req = bpf_peers_present(lc->ifp->if_bpf);
1383 	lagg_bpf_req = false;
1384 	lagg_ifp = NULL;
1385 	if (lc->ifp->if_type == IFT_IEEE8023ADLAG ||
1386 	    lc->ifp->if_type == IFT_INFINIBANDLAG) {
1387 		struct lagg_port *lp = lc->ifp->if_lagg;
1388 		struct lagg_softc *sc = lp->lp_softc;
1389 
1390 		lagg_ifp = sc->sc_ifp;
1391 		if (lagg_ifp != NULL)
1392 			lagg_bpf_req = bpf_peers_present(lagg_ifp->if_bpf);
1393 	}
1394 
1395 	/* Strip and compress all the incoming packets. */
1396  	can_append_old_cmp = true;
1397 	cmp = NULL;
1398 	for (pp = &le->m_head; *pp != NULL; ) {
1399 		mv_to = NULL;
1400 		if (do_bpf_strip_and_compress(inp, lc, le, pp,
1401 			&cmp, &mv_to, &should_wake, bpf_req,
1402  			lagg_bpf_req, lagg_ifp, can_append_old_cmp) == false) {
1403 			/* Advance to next mbuf. */
1404 			pp = &(*pp)->m_nextpkt;
1405  			/*
1406  			 * Once we have appended we can't look in the pending
1407  			 * inbound packets for a compressed ack to append to.
1408  			 */
1409  			can_append_old_cmp = false;
1410  			/*
1411  			 * Once we append we also need to stop adding to any
1412  			 * compressed ack we were remembering. A new cmp
1413  			 * ack will be required.
1414  			 */
1415  			cmp = NULL;
1416  			tcp_lro_log(tp, lc, le, NULL, 25, 0, 0, 0, 0);
1417 		} else if (mv_to != NULL) {
1418 			/* We are asked to move pp up */
1419 			pp = &mv_to->m_nextpkt;
1420  			tcp_lro_log(tp, lc, le, NULL, 24, 0, 0, 0, 0);
1421 		} else
1422  			tcp_lro_log(tp, lc, le, NULL, 26, 0, 0, 0, 0);
1423 	}
1424 	/* Update "m_last_mbuf", if any. */
1425 	if (pp == &le->m_head)
1426 		le->m_last_mbuf = *pp;
1427 	else
1428 		le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
1429 
1430 	/* Check if any data mbufs left. */
1431 	if (le->m_head != NULL) {
1432 		counter_u64_add(tcp_inp_lro_direct_queue, 1);
1433 		tcp_lro_log(tp, lc, le, NULL, 22, 1, inp->inp_flags2, 0, 1);
1434 		tcp_queue_pkts(inp, tp, le);
1435 	}
1436 	if (should_wake) {
1437 		/* Wakeup */
1438 		counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
1439 		if ((*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0))
1440 			inp = NULL;
1441 	}
1442 	if (inp != NULL)
1443 		INP_WUNLOCK(inp);
1444 	return (0);	/* Success. */
1445 }
1446 #endif
1447 
1448 void
1449 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
1450 {
1451 	/* Only optimise if there are multiple packets waiting. */
1452 #ifdef TCPHPTS
1453 	int error;
1454 #endif
1455 
1456 	NET_EPOCH_ASSERT();
1457 #ifdef TCPHPTS
1458 	CURVNET_SET(lc->ifp->if_vnet);
1459 	error = tcp_lro_flush_tcphpts(lc, le);
1460 	CURVNET_RESTORE();
1461 	if (error != 0) {
1462 #endif
1463 		tcp_lro_condense(lc, le);
1464 		tcp_flush_out_entry(lc, le);
1465 #ifdef TCPHPTS
1466 	}
1467 #endif
1468 	lc->lro_flushed++;
1469 	bzero(le, sizeof(*le));
1470 	LIST_INSERT_HEAD(&lc->lro_free, le, next);
1471 }
1472 
1473 #ifdef HAVE_INLINE_FLSLL
1474 #define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
1475 #else
1476 static inline uint64_t
1477 tcp_lro_msb_64(uint64_t x)
1478 {
1479 	x |= (x >> 1);
1480 	x |= (x >> 2);
1481 	x |= (x >> 4);
1482 	x |= (x >> 8);
1483 	x |= (x >> 16);
1484 	x |= (x >> 32);
1485 	return (x & ~(x >> 1));
1486 }
1487 #endif
1488 
1489 /*
1490  * The tcp_lro_sort() routine is comparable to qsort(), except it has
1491  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
1492  * number of elements to sort and 64 is the number of sequence bits
1493  * available. The algorithm is bit-slicing the 64-bit sequence number,
1494  * sorting one bit at a time from the most significant bit until the
1495  * least significant one, skipping the constant bits. This is
1496  * typically called a radix sort.
1497  */
1498 static void
1499 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
1500 {
1501 	struct lro_mbuf_sort temp;
1502 	uint64_t ones;
1503 	uint64_t zeros;
1504 	uint32_t x;
1505 	uint32_t y;
1506 
1507 repeat:
1508 	/* for small arrays insertion sort is faster */
1509 	if (size <= 12) {
1510 		for (x = 1; x < size; x++) {
1511 			temp = parray[x];
1512 			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
1513 				parray[y] = parray[y - 1];
1514 			parray[y] = temp;
1515 		}
1516 		return;
1517 	}
1518 
1519 	/* compute sequence bits which are constant */
1520 	ones = 0;
1521 	zeros = 0;
1522 	for (x = 0; x != size; x++) {
1523 		ones |= parray[x].seq;
1524 		zeros |= ~parray[x].seq;
1525 	}
1526 
1527 	/* compute bits which are not constant into "ones" */
1528 	ones &= zeros;
1529 	if (ones == 0)
1530 		return;
1531 
1532 	/* pick the most significant bit which is not constant */
1533 	ones = tcp_lro_msb_64(ones);
1534 
1535 	/*
1536 	 * Move entries having cleared sequence bits to the beginning
1537 	 * of the array:
1538 	 */
1539 	for (x = y = 0; y != size; y++) {
1540 		/* skip set bits */
1541 		if (parray[y].seq & ones)
1542 			continue;
1543 		/* swap entries */
1544 		temp = parray[x];
1545 		parray[x] = parray[y];
1546 		parray[y] = temp;
1547 		x++;
1548 	}
1549 
1550 	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
1551 
1552 	/* sort zeros */
1553 	tcp_lro_sort(parray, x);
1554 
1555 	/* sort ones */
1556 	parray += x;
1557 	size -= x;
1558 	goto repeat;
1559 }
1560 
1561 void
1562 tcp_lro_flush_all(struct lro_ctrl *lc)
1563 {
1564 	uint64_t seq;
1565 	uint64_t nseq;
1566 	unsigned x;
1567 
1568 	NET_EPOCH_ASSERT();
1569 	/* check if no mbufs to flush */
1570 	if (lc->lro_mbuf_count == 0)
1571 		goto done;
1572 	if (lc->lro_cpu_is_set == 0) {
1573 		if (lc->lro_last_cpu == curcpu) {
1574 			lc->lro_cnt_of_same_cpu++;
1575 			/* Have we reached the threshold to declare a cpu? */
1576 			if (lc->lro_cnt_of_same_cpu > tcp_lro_cpu_set_thresh)
1577 				lc->lro_cpu_is_set = 1;
1578 		} else {
1579 			lc->lro_last_cpu = curcpu;
1580 			lc->lro_cnt_of_same_cpu = 0;
1581 		}
1582 	}
1583 	CURVNET_SET(lc->ifp->if_vnet);
1584 
1585 	/* get current time */
1586 	binuptime(&lc->lro_last_queue_time);
1587 
1588 	/* sort all mbufs according to stream */
1589 	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
1590 
1591 	/* input data into LRO engine, stream by stream */
1592 	seq = 0;
1593 	for (x = 0; x != lc->lro_mbuf_count; x++) {
1594 		struct mbuf *mb;
1595 
1596 		/* get mbuf */
1597 		mb = lc->lro_mbuf_data[x].mb;
1598 
1599 		/* get sequence number, masking away the packet index */
1600 		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
1601 
1602 		/* check for new stream */
1603 		if (seq != nseq) {
1604 			seq = nseq;
1605 
1606 			/* flush active streams */
1607 			tcp_lro_rx_done(lc);
1608 		}
1609 
1610 		/* add packet to LRO engine */
1611 		if (tcp_lro_rx_common(lc, mb, 0, false) != 0) {
1612  			/* Flush anything we have acummulated */
1613  			tcp_lro_flush_active(lc);
1614 			/* input packet to network layer */
1615 			(*lc->ifp->if_input)(lc->ifp, mb);
1616 			lc->lro_queued++;
1617 			lc->lro_flushed++;
1618 		}
1619 	}
1620 	CURVNET_RESTORE();
1621 done:
1622 	/* flush active streams */
1623 	tcp_lro_rx_done(lc);
1624 
1625 #ifdef TCPHPTS
1626 	tcp_run_hpts();
1627 #endif
1628 	lc->lro_mbuf_count = 0;
1629 }
1630 
1631 #ifdef TCPHPTS
1632 static void
1633 build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
1634     uint32_t *ts_ptr, uint16_t iptos)
1635 {
1636 	/*
1637 	 * Given a TCP ACK, summarize it down into the small TCP ACK
1638 	 * entry.
1639 	 */
1640 	ae->timestamp = m->m_pkthdr.rcv_tstmp;
1641 	ae->flags = 0;
1642 	if (m->m_flags & M_TSTMP_LRO)
1643 		ae->flags |= TSTMP_LRO;
1644 	else if (m->m_flags & M_TSTMP)
1645 		ae->flags |= TSTMP_HDWR;
1646 	ae->seq = ntohl(th->th_seq);
1647 	ae->ack = ntohl(th->th_ack);
1648 	ae->flags |= tcp_get_flags(th);
1649 	if (ts_ptr != NULL) {
1650 		ae->ts_value = ntohl(ts_ptr[1]);
1651 		ae->ts_echo = ntohl(ts_ptr[2]);
1652 		ae->flags |= HAS_TSTMP;
1653 	}
1654 	ae->win = ntohs(th->th_win);
1655 	ae->codepoint = iptos;
1656 }
1657 
1658 /*
1659  * Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
1660  * and strip all, but the IPv4/IPv6 header.
1661  */
1662 static bool
1663 do_bpf_strip_and_compress(struct inpcb *inp, struct lro_ctrl *lc,
1664     struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp, struct mbuf **mv_to,
1665     bool *should_wake, bool bpf_req, bool lagg_bpf_req, struct ifnet *lagg_ifp, bool can_append_old_cmp)
1666 {
1667 	union {
1668 		void *ptr;
1669 		struct ip *ip4;
1670 		struct ip6_hdr *ip6;
1671 	} l3;
1672 	struct mbuf *m;
1673 	struct mbuf *nm;
1674 	struct tcphdr *th;
1675 	struct tcp_ackent *ack_ent;
1676 	uint32_t *ts_ptr;
1677 	int32_t n_mbuf;
1678 	bool other_opts, can_compress;
1679 	uint8_t lro_type;
1680 	uint16_t iptos;
1681 	int tcp_hdr_offset;
1682 	int idx;
1683 
1684 	/* Get current mbuf. */
1685 	m = *pp;
1686 
1687 	/* Let the BPF see the packet */
1688 	if (__predict_false(bpf_req))
1689 		ETHER_BPF_MTAP(lc->ifp, m);
1690 
1691 	if (__predict_false(lagg_bpf_req))
1692 		ETHER_BPF_MTAP(lagg_ifp, m);
1693 
1694 	tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
1695 	lro_type = le->inner.data.lro_type;
1696 	switch (lro_type) {
1697 	case LRO_TYPE_NONE:
1698 		lro_type = le->outer.data.lro_type;
1699 		switch (lro_type) {
1700 		case LRO_TYPE_IPV4_TCP:
1701 			tcp_hdr_offset -= sizeof(*le->outer.ip4);
1702 			m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1703 			break;
1704 		case LRO_TYPE_IPV6_TCP:
1705 			tcp_hdr_offset -= sizeof(*le->outer.ip6);
1706 			m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1707 			break;
1708 		default:
1709 			goto compressed;
1710 		}
1711 		break;
1712 	case LRO_TYPE_IPV4_TCP:
1713 		tcp_hdr_offset -= sizeof(*le->outer.ip4);
1714 		m->m_pkthdr.lro_etype = ETHERTYPE_IP;
1715 		break;
1716 	case LRO_TYPE_IPV6_TCP:
1717 		tcp_hdr_offset -= sizeof(*le->outer.ip6);
1718 		m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
1719 		break;
1720 	default:
1721 		goto compressed;
1722 	}
1723 
1724 	MPASS(tcp_hdr_offset >= 0);
1725 
1726 	m_adj(m, tcp_hdr_offset);
1727 	m->m_flags |= M_LRO_EHDRSTRP;
1728 	m->m_flags &= ~M_ACKCMP;
1729 	m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
1730 
1731 	th = tcp_lro_get_th(m);
1732 
1733 	th->th_sum = 0;		/* TCP checksum is valid. */
1734 
1735 	/* Check if ACK can be compressed */
1736 	can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
1737 
1738 	/* Now lets look at the should wake states */
1739 	if ((other_opts == true) &&
1740 	    ((inp->inp_flags2 & INP_DONT_SACK_QUEUE) == 0)) {
1741 		/*
1742 		 * If there are other options (SACK?) and the
1743 		 * tcp endpoint has not expressly told us it does
1744 		 * not care about SACKS, then we should wake up.
1745 		 */
1746 		*should_wake = true;
1747 	}
1748 	/* Is the ack compressable? */
1749 	if (can_compress == false)
1750 		goto done;
1751 	/* Does the TCP endpoint support ACK compression? */
1752 	if ((inp->inp_flags2 & INP_MBUF_ACKCMP) == 0)
1753 		goto done;
1754 
1755 	/* Lets get the TOS/traffic class field */
1756 	l3.ptr = mtod(m, void *);
1757 	switch (lro_type) {
1758 	case LRO_TYPE_IPV4_TCP:
1759 		iptos = l3.ip4->ip_tos;
1760 		break;
1761 	case LRO_TYPE_IPV6_TCP:
1762 		iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
1763 		break;
1764 	default:
1765 		iptos = 0;	/* Keep compiler happy. */
1766 		break;
1767 	}
1768 	/* Now lets get space if we don't have some already */
1769 	if (*cmp == NULL) {
1770 new_one:
1771 		nm = tcp_lro_get_last_if_ackcmp(lc, le, inp, &n_mbuf, can_append_old_cmp);
1772 		if (__predict_false(nm == NULL))
1773 			goto done;
1774 		*cmp = nm;
1775 		if (n_mbuf) {
1776 			/*
1777 			 *  Link in the new cmp ack to our in-order place,
1778 			 * first set our cmp ack's next to where we are.
1779 			 */
1780 			nm->m_nextpkt = m;
1781 			(*pp) = nm;
1782 			/*
1783 			 * Set it up so mv_to is advanced to our
1784 			 * compressed ack. This way the caller can
1785 			 * advance pp to the right place.
1786 			 */
1787 			*mv_to = nm;
1788 			/*
1789 			 * Advance it here locally as well.
1790 			 */
1791 			pp = &nm->m_nextpkt;
1792 		}
1793 	} else {
1794 		/* We have one already we are working on */
1795 		nm = *cmp;
1796 		if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
1797 			/* We ran out of space */
1798 			inp->inp_flags2 |= INP_MBUF_L_ACKS;
1799 			goto new_one;
1800 		}
1801 	}
1802 	MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
1803 	counter_u64_add(tcp_inp_lro_compressed, 1);
1804 	le->compressed++;
1805 	/* We can add in to the one on the tail */
1806 	ack_ent = mtod(nm, struct tcp_ackent *);
1807 	idx = (nm->m_len / sizeof(struct tcp_ackent));
1808 	build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
1809 
1810 	/* Bump the size of both pkt-hdr and len */
1811 	nm->m_len += sizeof(struct tcp_ackent);
1812 	nm->m_pkthdr.len += sizeof(struct tcp_ackent);
1813 compressed:
1814 	/* Advance to next mbuf before freeing. */
1815 	*pp = m->m_nextpkt;
1816 	m->m_nextpkt = NULL;
1817 	m_freem(m);
1818 	return (true);
1819 done:
1820 	counter_u64_add(tcp_uncomp_total, 1);
1821 	le->uncompressed++;
1822 	return (false);
1823 }
1824 #endif
1825 
1826 static struct lro_head *
1827 tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser)
1828 {
1829 	u_long hash;
1830 
1831 	if (M_HASHTYPE_ISHASH(m)) {
1832 		hash = m->m_pkthdr.flowid;
1833 	} else {
1834 		for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++)
1835 			hash += parser->data.raw[i];
1836 	}
1837 	return (&lc->lro_hash[hash % lc->lro_hashsz]);
1838 }
1839 
1840 static int
1841 tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash)
1842 {
1843 	struct lro_parser pi;	/* inner address data */
1844 	struct lro_parser po;	/* outer address data */
1845 	struct lro_parser *pa;	/* current parser for TCP stream */
1846 	struct lro_entry *le;
1847 	struct lro_head *bucket;
1848 	struct tcphdr *th;
1849 	int tcp_data_len;
1850 	int tcp_opt_len;
1851 	int error;
1852 	uint16_t tcp_data_sum;
1853 
1854 #ifdef INET
1855 	/* Quickly decide if packet cannot be LRO'ed */
1856 	if (__predict_false(V_ipforwarding != 0))
1857 		return (TCP_LRO_CANNOT);
1858 #endif
1859 #ifdef INET6
1860 	/* Quickly decide if packet cannot be LRO'ed */
1861 	if (__predict_false(V_ip6_forwarding != 0))
1862 		return (TCP_LRO_CANNOT);
1863 #endif
1864 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1865 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1866 	    (m->m_pkthdr.csum_data != 0xffff)) {
1867 		/*
1868 		 * The checksum either did not have hardware offload
1869 		 * or it was a bad checksum. We can't LRO such
1870 		 * a packet.
1871 		 */
1872 		counter_u64_add(tcp_bad_csums, 1);
1873 		return (TCP_LRO_CANNOT);
1874 	}
1875 	/* We expect a contiguous header [eh, ip, tcp]. */
1876 	pa = tcp_lro_parser(m, &po, &pi, true);
1877 	if (__predict_false(pa == NULL))
1878 		return (TCP_LRO_NOT_SUPPORTED);
1879 
1880 	/* We don't expect any padding. */
1881 	error = tcp_lro_trim_mbuf_chain(m, pa);
1882 	if (__predict_false(error != 0))
1883 		return (error);
1884 
1885 #ifdef INET
1886 	switch (pa->data.lro_type) {
1887 	case LRO_TYPE_IPV4_TCP:
1888 		error = tcp_lro_rx_ipv4(lc, m, pa->ip4);
1889 		if (__predict_false(error != 0))
1890 			return (error);
1891 		break;
1892 	default:
1893 		break;
1894 	}
1895 #endif
1896 	/* If no hardware or arrival stamp on the packet add timestamp */
1897 	if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
1898 		m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
1899 		m->m_flags |= M_TSTMP_LRO;
1900 	}
1901 
1902 	/* Get pointer to TCP header. */
1903 	th = pa->tcp;
1904 
1905 	/* Don't process SYN packets. */
1906 	if (__predict_false(tcp_get_flags(th) & TH_SYN))
1907 		return (TCP_LRO_CANNOT);
1908 
1909 	/* Get total TCP header length and compute payload length. */
1910 	tcp_opt_len = (th->th_off << 2);
1911 	tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th -
1912 	    (uint8_t *)m->m_data) - tcp_opt_len;
1913 	tcp_opt_len -= sizeof(*th);
1914 
1915 	/* Don't process invalid TCP headers. */
1916 	if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0))
1917 		return (TCP_LRO_CANNOT);
1918 
1919 	/* Compute TCP data only checksum. */
1920 	if (tcp_data_len == 0)
1921 		tcp_data_sum = 0;	/* no data, no checksum */
1922 	else if (__predict_false(csum != 0))
1923 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum);
1924 	else
1925 		tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum);
1926 
1927 	/* Save TCP info in mbuf. */
1928 	m->m_nextpkt = NULL;
1929 	m->m_pkthdr.rcvif = lc->ifp;
1930 	m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum;
1931 	m->m_pkthdr.lro_tcp_d_len = tcp_data_len;
1932 	m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data);
1933 	m->m_pkthdr.lro_nsegs = 1;
1934 
1935 	/* Get hash bucket. */
1936 	if (!use_hash) {
1937 		bucket = &lc->lro_hash[0];
1938 	} else {
1939 		bucket = tcp_lro_rx_get_bucket(lc, m, pa);
1940 	}
1941 
1942 	/* Try to find a matching previous segment. */
1943 	LIST_FOREACH(le, bucket, hash_next) {
1944 		/* Compare addresses and ports. */
1945 		if (lro_address_compare(&po.data, &le->outer.data) == false ||
1946 		    lro_address_compare(&pi.data, &le->inner.data) == false)
1947 			continue;
1948 
1949 		/* Check if no data and old ACK. */
1950 		if (tcp_data_len == 0 &&
1951 		    SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
1952 			m_freem(m);
1953 			return (0);
1954 		}
1955 
1956 		/* Mark "m" in the last spot. */
1957 		le->m_last_mbuf->m_nextpkt = m;
1958 		/* Now set the tail to "m". */
1959 		le->m_last_mbuf = m;
1960 		return (0);
1961 	}
1962 
1963 	/* Try to find an empty slot. */
1964 	if (LIST_EMPTY(&lc->lro_free))
1965 		return (TCP_LRO_NO_ENTRIES);
1966 
1967 	/* Start a new segment chain. */
1968 	le = LIST_FIRST(&lc->lro_free);
1969 	LIST_REMOVE(le, next);
1970 	tcp_lro_active_insert(lc, bucket, le);
1971 
1972 	/* Make sure the headers are set. */
1973 	le->inner = pi;
1974 	le->outer = po;
1975 
1976 	/* Store time this entry was allocated. */
1977 	le->alloc_time = lc->lro_last_queue_time;
1978 
1979 	tcp_set_entry_to_mbuf(lc, le, m, th);
1980 
1981 	/* Now set the tail to "m". */
1982 	le->m_last_mbuf = m;
1983 
1984 	return (0);
1985 }
1986 
1987 int
1988 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
1989 {
1990 	int error;
1991 
1992 	if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) !=
1993 	     ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) ||
1994 	    (m->m_pkthdr.csum_data != 0xffff)) {
1995 		/*
1996 		 * The checksum either did not have hardware offload
1997 		 * or it was a bad checksum. We can't LRO such
1998 		 * a packet.
1999 		 */
2000 		counter_u64_add(tcp_bad_csums, 1);
2001 		return (TCP_LRO_CANNOT);
2002 	}
2003 	/* get current time */
2004 	binuptime(&lc->lro_last_queue_time);
2005 	CURVNET_SET(lc->ifp->if_vnet);
2006 	error = tcp_lro_rx_common(lc, m, csum, true);
2007 	if (__predict_false(error != 0)) {
2008 		/*
2009 		 * Flush anything we have acummulated
2010 		 * ahead of this packet that can't
2011 		 * be LRO'd. This preserves order.
2012 		 */
2013 		tcp_lro_flush_active(lc);
2014 	}
2015 	CURVNET_RESTORE();
2016 
2017 	return (error);
2018 }
2019 
2020 void
2021 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
2022 {
2023 	NET_EPOCH_ASSERT();
2024 	/* sanity checks */
2025 	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
2026 	    lc->lro_mbuf_max == 0)) {
2027 		/* packet drop */
2028 		m_freem(mb);
2029 		return;
2030 	}
2031 
2032 	/* check if packet is not LRO capable */
2033 	if (__predict_false((lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
2034 		/* input packet to network layer */
2035 		(*lc->ifp->if_input) (lc->ifp, mb);
2036 		return;
2037 	}
2038 
2039  	/* If no hardware or arrival stamp on the packet add timestamp */
2040  	if ((tcplro_stacks_wanting_mbufq > 0) &&
2041  	    (tcp_less_accurate_lro_ts == 0) &&
2042  	    ((mb->m_flags & M_TSTMP) == 0)) {
2043  		/* Add in an LRO time since no hardware */
2044  		binuptime(&lc->lro_last_queue_time);
2045  		mb->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
2046  		mb->m_flags |= M_TSTMP_LRO;
2047  	}
2048 
2049 	/* create sequence number */
2050 	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
2051 	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
2052 	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
2053 	    ((uint64_t)lc->lro_mbuf_count);
2054 
2055 	/* enter mbuf */
2056 	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
2057 
2058 	/* flush if array is full */
2059 	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
2060 		tcp_lro_flush_all(lc);
2061 }
2062 
2063 /* end */
2064