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 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/sysctl.h>
48
49#include <net/if.h>
50#include <net/if_var.h>
51#include <net/ethernet.h>
52#include <net/vnet.h>
53
54#include <netinet/in_systm.h>
55#include <netinet/in.h>
56#include <netinet/ip6.h>
57#include <netinet/ip.h>
58#include <netinet/ip_var.h>
59#include <netinet/tcp.h>
60#include <netinet/tcp_seq.h>
61#include <netinet/tcp_lro.h>
62#include <netinet/tcp_var.h>
63
64#include <netinet6/ip6_var.h>
65
66#include <machine/in_cksum.h>
67
68static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures");
69
70#define	TCP_LRO_UPDATE_CSUM	1
71#ifndef	TCP_LRO_UPDATE_CSUM
72#define	TCP_LRO_INVALID_CSUM	0x0000
73#endif
74
75static void	tcp_lro_rx_done(struct lro_ctrl *lc);
76static int	tcp_lro_rx2(struct lro_ctrl *lc, struct mbuf *m,
77		    uint32_t csum, int use_hash);
78
79SYSCTL_NODE(_net_inet_tcp, OID_AUTO, lro,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
80    "TCP LRO");
81
82static unsigned	tcp_lro_entries = TCP_LRO_ENTRIES;
83SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries,
84    CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0,
85    "default number of LRO entries");
86
87static __inline void
88tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_head *bucket,
89    struct lro_entry *le)
90{
91
92	LIST_INSERT_HEAD(&lc->lro_active, le, next);
93	LIST_INSERT_HEAD(bucket, le, hash_next);
94}
95
96static __inline void
97tcp_lro_active_remove(struct lro_entry *le)
98{
99
100	LIST_REMOVE(le, next);		/* active list */
101	LIST_REMOVE(le, hash_next);	/* hash bucket */
102}
103
104int
105tcp_lro_init(struct lro_ctrl *lc)
106{
107	return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0));
108}
109
110int
111tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
112    unsigned lro_entries, unsigned lro_mbufs)
113{
114	struct lro_entry *le;
115	size_t size;
116	unsigned i, elements;
117
118	lc->lro_bad_csum = 0;
119	lc->lro_queued = 0;
120	lc->lro_flushed = 0;
121	lc->lro_mbuf_count = 0;
122	lc->lro_mbuf_max = lro_mbufs;
123	lc->lro_cnt = lro_entries;
124	lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
125	lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
126	lc->ifp = ifp;
127	LIST_INIT(&lc->lro_free);
128	LIST_INIT(&lc->lro_active);
129
130	/* create hash table to accelerate entry lookup */
131	if (lro_entries > lro_mbufs)
132		elements = lro_entries;
133	else
134		elements = lro_mbufs;
135	lc->lro_hash = phashinit_flags(elements, M_LRO, &lc->lro_hashsz,
136	    HASH_NOWAIT);
137	if (lc->lro_hash == NULL) {
138		memset(lc, 0, sizeof(*lc));
139		return (ENOMEM);
140	}
141
142	/* compute size to allocate */
143	size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
144	    (lro_entries * sizeof(*le));
145	lc->lro_mbuf_data = (struct lro_mbuf_sort *)
146	    malloc(size, M_LRO, M_NOWAIT | M_ZERO);
147
148	/* check for out of memory */
149	if (lc->lro_mbuf_data == NULL) {
150		free(lc->lro_hash, M_LRO);
151		memset(lc, 0, sizeof(*lc));
152		return (ENOMEM);
153	}
154	/* compute offset for LRO entries */
155	le = (struct lro_entry *)
156	    (lc->lro_mbuf_data + lro_mbufs);
157
158	/* setup linked list */
159	for (i = 0; i != lro_entries; i++)
160		LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
161
162	return (0);
163}
164
165void
166tcp_lro_free(struct lro_ctrl *lc)
167{
168	struct lro_entry *le;
169	unsigned x;
170
171	/* reset LRO free list */
172	LIST_INIT(&lc->lro_free);
173
174	/* free active mbufs, if any */
175	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
176		tcp_lro_active_remove(le);
177		m_freem(le->m_head);
178	}
179
180	/* free hash table */
181	free(lc->lro_hash, M_LRO);
182	lc->lro_hash = NULL;
183	lc->lro_hashsz = 0;
184
185	/* free mbuf array, if any */
186	for (x = 0; x != lc->lro_mbuf_count; x++)
187		m_freem(lc->lro_mbuf_data[x].mb);
188	lc->lro_mbuf_count = 0;
189
190	/* free allocated memory, if any */
191	free(lc->lro_mbuf_data, M_LRO);
192	lc->lro_mbuf_data = NULL;
193}
194
195#ifdef TCP_LRO_UPDATE_CSUM
196static uint16_t
197tcp_lro_csum_th(struct tcphdr *th)
198{
199	uint32_t ch;
200	uint16_t *p, l;
201
202	ch = th->th_sum = 0x0000;
203	l = th->th_off;
204	p = (uint16_t *)th;
205	while (l > 0) {
206		ch += *p;
207		p++;
208		ch += *p;
209		p++;
210		l--;
211	}
212	while (ch > 0xffff)
213		ch = (ch >> 16) + (ch & 0xffff);
214
215	return (ch & 0xffff);
216}
217
218static uint16_t
219tcp_lro_rx_csum_fixup(struct lro_entry *le, void *l3hdr, struct tcphdr *th,
220    uint16_t tcp_data_len, uint16_t csum)
221{
222	uint32_t c;
223	uint16_t cs;
224
225	c = csum;
226
227	/* Remove length from checksum. */
228	switch (le->eh_type) {
229#ifdef INET6
230	case ETHERTYPE_IPV6:
231	{
232		struct ip6_hdr *ip6;
233
234		ip6 = (struct ip6_hdr *)l3hdr;
235		if (le->append_cnt == 0)
236			cs = ip6->ip6_plen;
237		else {
238			uint32_t cx;
239
240			cx = ntohs(ip6->ip6_plen);
241			cs = in6_cksum_pseudo(ip6, cx, ip6->ip6_nxt, 0);
242		}
243		break;
244	}
245#endif
246#ifdef INET
247	case ETHERTYPE_IP:
248	{
249		struct ip *ip4;
250
251		ip4 = (struct ip *)l3hdr;
252		if (le->append_cnt == 0)
253			cs = ip4->ip_len;
254		else {
255			cs = in_addword(ntohs(ip4->ip_len) - sizeof(*ip4),
256			    IPPROTO_TCP);
257			cs = in_pseudo(ip4->ip_src.s_addr, ip4->ip_dst.s_addr,
258			    htons(cs));
259		}
260		break;
261	}
262#endif
263	default:
264		cs = 0;		/* Keep compiler happy. */
265	}
266
267	cs = ~cs;
268	c += cs;
269
270	/* Remove TCP header csum. */
271	cs = ~tcp_lro_csum_th(th);
272	c += cs;
273	while (c > 0xffff)
274		c = (c >> 16) + (c & 0xffff);
275
276	return (c & 0xffff);
277}
278#endif
279
280static void
281tcp_lro_rx_done(struct lro_ctrl *lc)
282{
283	struct lro_entry *le;
284
285	while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
286		tcp_lro_active_remove(le);
287		tcp_lro_flush(lc, le);
288	}
289}
290
291void
292tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
293{
294	struct lro_entry *le, *le_tmp;
295	struct timeval tv;
296
297	if (LIST_EMPTY(&lc->lro_active))
298		return;
299
300	getmicrotime(&tv);
301	timevalsub(&tv, timeout);
302	LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
303		if (timevalcmp(&tv, &le->mtime, >=)) {
304			tcp_lro_active_remove(le);
305			tcp_lro_flush(lc, le);
306		}
307	}
308}
309
310void
311tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
312{
313
314	if (le->append_cnt > 0) {
315		struct tcphdr *th;
316		uint16_t p_len;
317
318		p_len = htons(le->p_len);
319		switch (le->eh_type) {
320#ifdef INET6
321		case ETHERTYPE_IPV6:
322		{
323			struct ip6_hdr *ip6;
324
325			ip6 = le->le_ip6;
326			ip6->ip6_plen = p_len;
327			th = (struct tcphdr *)(ip6 + 1);
328			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
329			    CSUM_PSEUDO_HDR;
330			le->p_len += ETHER_HDR_LEN + sizeof(*ip6);
331			break;
332		}
333#endif
334#ifdef INET
335		case ETHERTYPE_IP:
336		{
337			struct ip *ip4;
338#ifdef TCP_LRO_UPDATE_CSUM
339			uint32_t cl;
340			uint16_t c;
341#endif
342
343			ip4 = le->le_ip4;
344#ifdef TCP_LRO_UPDATE_CSUM
345			/* Fix IP header checksum for new length. */
346			c = ~ip4->ip_sum;
347			cl = c;
348			c = ~ip4->ip_len;
349			cl += c + p_len;
350			while (cl > 0xffff)
351				cl = (cl >> 16) + (cl & 0xffff);
352			c = cl;
353			ip4->ip_sum = ~c;
354#else
355			ip4->ip_sum = TCP_LRO_INVALID_CSUM;
356#endif
357			ip4->ip_len = p_len;
358			th = (struct tcphdr *)(ip4 + 1);
359			le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
360			    CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
361			le->p_len += ETHER_HDR_LEN;
362			break;
363		}
364#endif
365		default:
366			th = NULL;	/* Keep compiler happy. */
367		}
368		le->m_head->m_pkthdr.csum_data = 0xffff;
369		le->m_head->m_pkthdr.len = le->p_len;
370
371		/* Incorporate the latest ACK into the TCP header. */
372		th->th_ack = le->ack_seq;
373		th->th_win = le->window;
374		/* Incorporate latest timestamp into the TCP header. */
375		if (le->timestamp != 0) {
376			uint32_t *ts_ptr;
377
378			ts_ptr = (uint32_t *)(th + 1);
379			ts_ptr[1] = htonl(le->tsval);
380			ts_ptr[2] = le->tsecr;
381		}
382#ifdef TCP_LRO_UPDATE_CSUM
383		/* Update the TCP header checksum. */
384		le->ulp_csum += p_len;
385		le->ulp_csum += tcp_lro_csum_th(th);
386		while (le->ulp_csum > 0xffff)
387			le->ulp_csum = (le->ulp_csum >> 16) +
388			    (le->ulp_csum & 0xffff);
389		th->th_sum = (le->ulp_csum & 0xffff);
390		th->th_sum = ~th->th_sum;
391#else
392		th->th_sum = TCP_LRO_INVALID_CSUM;
393#endif
394	}
395
396	le->m_head->m_pkthdr.lro_nsegs = le->append_cnt + 1;
397	(*lc->ifp->if_input)(lc->ifp, le->m_head);
398	lc->lro_queued += le->append_cnt + 1;
399	lc->lro_flushed++;
400	bzero(le, sizeof(*le));
401	LIST_INSERT_HEAD(&lc->lro_free, le, next);
402}
403
404#ifdef HAVE_INLINE_FLSLL
405#define	tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
406#else
407static inline uint64_t
408tcp_lro_msb_64(uint64_t x)
409{
410	x |= (x >> 1);
411	x |= (x >> 2);
412	x |= (x >> 4);
413	x |= (x >> 8);
414	x |= (x >> 16);
415	x |= (x >> 32);
416	return (x & ~(x >> 1));
417}
418#endif
419
420/*
421 * The tcp_lro_sort() routine is comparable to qsort(), except it has
422 * a worst case complexity limit of O(MIN(N,64)*N), where N is the
423 * number of elements to sort and 64 is the number of sequence bits
424 * available. The algorithm is bit-slicing the 64-bit sequence number,
425 * sorting one bit at a time from the most significant bit until the
426 * least significant one, skipping the constant bits. This is
427 * typically called a radix sort.
428 */
429static void
430tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
431{
432	struct lro_mbuf_sort temp;
433	uint64_t ones;
434	uint64_t zeros;
435	uint32_t x;
436	uint32_t y;
437
438repeat:
439	/* for small arrays insertion sort is faster */
440	if (size <= 12) {
441		for (x = 1; x < size; x++) {
442			temp = parray[x];
443			for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
444				parray[y] = parray[y - 1];
445			parray[y] = temp;
446		}
447		return;
448	}
449
450	/* compute sequence bits which are constant */
451	ones = 0;
452	zeros = 0;
453	for (x = 0; x != size; x++) {
454		ones |= parray[x].seq;
455		zeros |= ~parray[x].seq;
456	}
457
458	/* compute bits which are not constant into "ones" */
459	ones &= zeros;
460	if (ones == 0)
461		return;
462
463	/* pick the most significant bit which is not constant */
464	ones = tcp_lro_msb_64(ones);
465
466	/*
467	 * Move entries having cleared sequence bits to the beginning
468	 * of the array:
469	 */
470	for (x = y = 0; y != size; y++) {
471		/* skip set bits */
472		if (parray[y].seq & ones)
473			continue;
474		/* swap entries */
475		temp = parray[x];
476		parray[x] = parray[y];
477		parray[y] = temp;
478		x++;
479	}
480
481	KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
482
483	/* sort zeros */
484	tcp_lro_sort(parray, x);
485
486	/* sort ones */
487	parray += x;
488	size -= x;
489	goto repeat;
490}
491
492void
493tcp_lro_flush_all(struct lro_ctrl *lc)
494{
495	uint64_t seq;
496	uint64_t nseq;
497	unsigned x;
498
499	/* check if no mbufs to flush */
500	if (lc->lro_mbuf_count == 0)
501		goto done;
502
503	/* sort all mbufs according to stream */
504	tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
505
506	/* input data into LRO engine, stream by stream */
507	seq = 0;
508	for (x = 0; x != lc->lro_mbuf_count; x++) {
509		struct mbuf *mb;
510
511		/* get mbuf */
512		mb = lc->lro_mbuf_data[x].mb;
513
514		/* get sequence number, masking away the packet index */
515		nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
516
517		/* check for new stream */
518		if (seq != nseq) {
519			seq = nseq;
520
521			/* flush active streams */
522			tcp_lro_rx_done(lc);
523		}
524
525		/* add packet to LRO engine */
526		if (tcp_lro_rx2(lc, mb, 0, 0) != 0) {
527			/* input packet to network layer */
528			(*lc->ifp->if_input)(lc->ifp, mb);
529			lc->lro_queued++;
530			lc->lro_flushed++;
531		}
532	}
533done:
534	/* flush active streams */
535	tcp_lro_rx_done(lc);
536
537	lc->lro_mbuf_count = 0;
538}
539
540#ifdef INET6
541static int
542tcp_lro_rx_ipv6(struct lro_ctrl *lc, struct mbuf *m, struct ip6_hdr *ip6,
543    struct tcphdr **th)
544{
545
546	/* XXX-BZ we should check the flow-label. */
547
548	/* XXX-BZ We do not yet support ext. hdrs. */
549	if (ip6->ip6_nxt != IPPROTO_TCP)
550		return (TCP_LRO_NOT_SUPPORTED);
551
552	/* Find the TCP header. */
553	*th = (struct tcphdr *)(ip6 + 1);
554
555	return (0);
556}
557#endif
558
559#ifdef INET
560static int
561tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4,
562    struct tcphdr **th)
563{
564	int csum_flags;
565	uint16_t csum;
566
567	if (ip4->ip_p != IPPROTO_TCP)
568		return (TCP_LRO_NOT_SUPPORTED);
569
570	/* Ensure there are no options. */
571	if ((ip4->ip_hl << 2) != sizeof (*ip4))
572		return (TCP_LRO_CANNOT);
573
574	/* .. and the packet is not fragmented. */
575	if (ip4->ip_off & htons(IP_MF|IP_OFFMASK))
576		return (TCP_LRO_CANNOT);
577
578	/* Legacy IP has a header checksum that needs to be correct. */
579	csum_flags = m->m_pkthdr.csum_flags;
580	if (csum_flags & CSUM_IP_CHECKED) {
581		if (__predict_false((csum_flags & CSUM_IP_VALID) == 0)) {
582			lc->lro_bad_csum++;
583			return (TCP_LRO_CANNOT);
584		}
585	} else {
586		csum = in_cksum_hdr(ip4);
587		if (__predict_false((csum) != 0)) {
588			lc->lro_bad_csum++;
589			return (TCP_LRO_CANNOT);
590		}
591	}
592
593	/* Find the TCP header (we assured there are no IP options). */
594	*th = (struct tcphdr *)(ip4 + 1);
595
596	return (0);
597}
598#endif
599
600static int
601tcp_lro_rx2(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, int use_hash)
602{
603	struct lro_entry *le;
604	struct ether_header *eh;
605#ifdef INET6
606	struct ip6_hdr *ip6 = NULL;	/* Keep compiler happy. */
607#endif
608#ifdef INET
609	struct ip *ip4 = NULL;		/* Keep compiler happy. */
610#endif
611	struct tcphdr *th;
612	void *l3hdr = NULL;		/* Keep compiler happy. */
613	uint32_t *ts_ptr;
614	tcp_seq seq;
615	int error, ip_len, l;
616	uint16_t eh_type, tcp_data_len;
617	struct lro_head *bucket;
618	int force_flush = 0;
619
620	/* We expect a contiguous header [eh, ip, tcp]. */
621
622	eh = mtod(m, struct ether_header *);
623	eh_type = ntohs(eh->ether_type);
624	switch (eh_type) {
625#ifdef INET6
626	case ETHERTYPE_IPV6:
627	{
628		CURVNET_SET(lc->ifp->if_vnet);
629		if (V_ip6_forwarding != 0) {
630			/* XXX-BZ stats but changing lro_ctrl is a problem. */
631			CURVNET_RESTORE();
632			return (TCP_LRO_CANNOT);
633		}
634		CURVNET_RESTORE();
635		l3hdr = ip6 = (struct ip6_hdr *)(eh + 1);
636		error = tcp_lro_rx_ipv6(lc, m, ip6, &th);
637		if (error != 0)
638			return (error);
639		tcp_data_len = ntohs(ip6->ip6_plen);
640		ip_len = sizeof(*ip6) + tcp_data_len;
641		break;
642	}
643#endif
644#ifdef INET
645	case ETHERTYPE_IP:
646	{
647		CURVNET_SET(lc->ifp->if_vnet);
648		if (V_ipforwarding != 0) {
649			/* XXX-BZ stats but changing lro_ctrl is a problem. */
650			CURVNET_RESTORE();
651			return (TCP_LRO_CANNOT);
652		}
653		CURVNET_RESTORE();
654		l3hdr = ip4 = (struct ip *)(eh + 1);
655		error = tcp_lro_rx_ipv4(lc, m, ip4, &th);
656		if (error != 0)
657			return (error);
658		ip_len = ntohs(ip4->ip_len);
659		tcp_data_len = ip_len - sizeof(*ip4);
660		break;
661	}
662#endif
663	/* XXX-BZ what happens in case of VLAN(s)? */
664	default:
665		return (TCP_LRO_NOT_SUPPORTED);
666	}
667
668	/*
669	 * If the frame is padded beyond the end of the IP packet, then we must
670	 * trim the extra bytes off.
671	 */
672	l = m->m_pkthdr.len - (ETHER_HDR_LEN + ip_len);
673	if (l != 0) {
674		if (l < 0)
675			/* Truncated packet. */
676			return (TCP_LRO_CANNOT);
677
678		m_adj(m, -l);
679	}
680
681	/*
682	 * Check TCP header constraints.
683	 */
684	/* Ensure no bits set besides ACK or PSH. */
685	if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
686		if (th->th_flags & TH_SYN)
687			return (TCP_LRO_CANNOT);
688		/*
689		 * Make sure that previously seen segements/ACKs are delivered
690		 * before this segement, e.g. FIN.
691		 */
692		force_flush = 1;
693	}
694
695	/* XXX-BZ We lose a ACK|PUSH flag concatenating multiple segments. */
696	/* XXX-BZ Ideally we'd flush on PUSH? */
697
698	/*
699	 * Check for timestamps.
700	 * Since the only option we handle are timestamps, we only have to
701	 * handle the simple case of aligned timestamps.
702	 */
703	l = (th->th_off << 2);
704	tcp_data_len -= l;
705	l -= sizeof(*th);
706	ts_ptr = (uint32_t *)(th + 1);
707	if (l != 0 && (__predict_false(l != TCPOLEN_TSTAMP_APPA) ||
708	    (*ts_ptr != ntohl(TCPOPT_NOP<<24|TCPOPT_NOP<<16|
709	    TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)))) {
710		/*
711		 * Make sure that previously seen segements/ACKs are delivered
712		 * before this segement.
713		 */
714		force_flush = 1;
715	}
716
717	/* If the driver did not pass in the checksum, set it now. */
718	if (csum == 0x0000)
719		csum = th->th_sum;
720
721	seq = ntohl(th->th_seq);
722
723	if (!use_hash) {
724		bucket = &lc->lro_hash[0];
725	} else if (M_HASHTYPE_ISHASH(m)) {
726		bucket = &lc->lro_hash[m->m_pkthdr.flowid % lc->lro_hashsz];
727	} else {
728		uint32_t hash;
729
730		switch (eh_type) {
731#ifdef INET
732		case ETHERTYPE_IP:
733			hash = ip4->ip_src.s_addr + ip4->ip_dst.s_addr;
734			break;
735#endif
736#ifdef INET6
737		case ETHERTYPE_IPV6:
738			hash = ip6->ip6_src.s6_addr32[0] +
739			    ip6->ip6_dst.s6_addr32[0];
740			hash += ip6->ip6_src.s6_addr32[1] +
741			    ip6->ip6_dst.s6_addr32[1];
742			hash += ip6->ip6_src.s6_addr32[2] +
743			    ip6->ip6_dst.s6_addr32[2];
744			hash += ip6->ip6_src.s6_addr32[3] +
745			    ip6->ip6_dst.s6_addr32[3];
746			break;
747#endif
748		default:
749			hash = 0;
750			break;
751		}
752		hash += th->th_sport + th->th_dport;
753		bucket = &lc->lro_hash[hash % lc->lro_hashsz];
754	}
755
756	/* Try to find a matching previous segment. */
757	LIST_FOREACH(le, bucket, hash_next) {
758		if (le->eh_type != eh_type)
759			continue;
760		if (le->source_port != th->th_sport ||
761		    le->dest_port != th->th_dport)
762			continue;
763		switch (eh_type) {
764#ifdef INET6
765		case ETHERTYPE_IPV6:
766			if (bcmp(&le->source_ip6, &ip6->ip6_src,
767			    sizeof(struct in6_addr)) != 0 ||
768			    bcmp(&le->dest_ip6, &ip6->ip6_dst,
769			    sizeof(struct in6_addr)) != 0)
770				continue;
771			break;
772#endif
773#ifdef INET
774		case ETHERTYPE_IP:
775			if (le->source_ip4 != ip4->ip_src.s_addr ||
776			    le->dest_ip4 != ip4->ip_dst.s_addr)
777				continue;
778			break;
779#endif
780		}
781
782		if (force_flush) {
783			/* Timestamps mismatch; this is a FIN, etc */
784			tcp_lro_active_remove(le);
785			tcp_lro_flush(lc, le);
786			return (TCP_LRO_CANNOT);
787		}
788
789		/* Flush now if appending will result in overflow. */
790		if (le->p_len > (lc->lro_length_lim - tcp_data_len)) {
791			tcp_lro_active_remove(le);
792			tcp_lro_flush(lc, le);
793			break;
794		}
795
796		/* Try to append the new segment. */
797		if (__predict_false(seq != le->next_seq ||
798		    (tcp_data_len == 0 &&
799		    le->ack_seq == th->th_ack &&
800		    le->window == th->th_win))) {
801			/* Out of order packet or duplicate ACK. */
802			tcp_lro_active_remove(le);
803			tcp_lro_flush(lc, le);
804			return (TCP_LRO_CANNOT);
805		}
806
807		if (l != 0) {
808			uint32_t tsval = ntohl(*(ts_ptr + 1));
809			/* Make sure timestamp values are increasing. */
810			/* XXX-BZ flip and use TSTMP_GEQ macro for this? */
811			if (__predict_false(le->tsval > tsval ||
812			    *(ts_ptr + 2) == 0))
813				return (TCP_LRO_CANNOT);
814			le->tsval = tsval;
815			le->tsecr = *(ts_ptr + 2);
816		}
817		if (tcp_data_len || SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
818			le->next_seq += tcp_data_len;
819			le->ack_seq = th->th_ack;
820			le->window = th->th_win;
821			le->append_cnt++;
822		} else if (th->th_ack == le->ack_seq) {
823			le->window = WIN_MAX(le->window, th->th_win);
824			le->append_cnt++;
825		} else {
826			/* no data and old ack */
827			le->append_cnt++;
828			m_freem(m);
829			return (0);
830		}
831#ifdef TCP_LRO_UPDATE_CSUM
832		le->ulp_csum += tcp_lro_rx_csum_fixup(le, l3hdr, th,
833		    tcp_data_len, ~csum);
834#endif
835
836		if (tcp_data_len == 0) {
837			m_freem(m);
838			/*
839			 * Flush this LRO entry, if this ACK should not
840			 * be further delayed.
841			 */
842			if (le->append_cnt >= lc->lro_ackcnt_lim) {
843				tcp_lro_active_remove(le);
844				tcp_lro_flush(lc, le);
845			}
846			return (0);
847		}
848
849		le->p_len += tcp_data_len;
850
851		/*
852		 * Adjust the mbuf so that m_data points to the first byte of
853		 * the ULP payload.  Adjust the mbuf to avoid complications and
854		 * append new segment to existing mbuf chain.
855		 */
856		m_adj(m, m->m_pkthdr.len - tcp_data_len);
857		m_demote_pkthdr(m);
858
859		le->m_tail->m_next = m;
860		le->m_tail = m_last(m);
861
862		/*
863		 * If a possible next full length packet would cause an
864		 * overflow, pro-actively flush now.
865		 */
866		if (le->p_len > (lc->lro_length_lim - lc->ifp->if_mtu)) {
867			tcp_lro_active_remove(le);
868			tcp_lro_flush(lc, le);
869		} else
870			getmicrotime(&le->mtime);
871
872		return (0);
873	}
874
875	if (force_flush) {
876		/*
877		 * Nothing to flush, but this segment can not be further
878		 * aggregated/delayed.
879		 */
880		return (TCP_LRO_CANNOT);
881	}
882
883	/* Try to find an empty slot. */
884	if (LIST_EMPTY(&lc->lro_free))
885		return (TCP_LRO_NO_ENTRIES);
886
887	/* Start a new segment chain. */
888	le = LIST_FIRST(&lc->lro_free);
889	LIST_REMOVE(le, next);
890	tcp_lro_active_insert(lc, bucket, le);
891	getmicrotime(&le->mtime);
892
893	/* Start filling in details. */
894	switch (eh_type) {
895#ifdef INET6
896	case ETHERTYPE_IPV6:
897		le->le_ip6 = ip6;
898		le->source_ip6 = ip6->ip6_src;
899		le->dest_ip6 = ip6->ip6_dst;
900		le->eh_type = eh_type;
901		le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN - sizeof(*ip6);
902		break;
903#endif
904#ifdef INET
905	case ETHERTYPE_IP:
906		le->le_ip4 = ip4;
907		le->source_ip4 = ip4->ip_src.s_addr;
908		le->dest_ip4 = ip4->ip_dst.s_addr;
909		le->eh_type = eh_type;
910		le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN;
911		break;
912#endif
913	}
914	le->source_port = th->th_sport;
915	le->dest_port = th->th_dport;
916
917	le->next_seq = seq + tcp_data_len;
918	le->ack_seq = th->th_ack;
919	le->window = th->th_win;
920	if (l != 0) {
921		le->timestamp = 1;
922		le->tsval = ntohl(*(ts_ptr + 1));
923		le->tsecr = *(ts_ptr + 2);
924	}
925
926#ifdef TCP_LRO_UPDATE_CSUM
927	/*
928	 * Do not touch the csum of the first packet.  However save the
929	 * "adjusted" checksum of just the source and destination addresses,
930	 * the next header and the TCP payload.  The length and TCP header
931	 * parts may change, so we remove those from the saved checksum and
932	 * re-add with final values on tcp_lro_flush() if needed.
933	 */
934	KASSERT(le->ulp_csum == 0, ("%s: le=%p le->ulp_csum=0x%04x\n",
935	    __func__, le, le->ulp_csum));
936
937	le->ulp_csum = tcp_lro_rx_csum_fixup(le, l3hdr, th, tcp_data_len,
938	    ~csum);
939	th->th_sum = csum;	/* Restore checksum on first packet. */
940#endif
941
942	le->m_head = m;
943	le->m_tail = m_last(m);
944
945	return (0);
946}
947
948int
949tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
950{
951
952	return tcp_lro_rx2(lc, m, csum, 1);
953}
954
955void
956tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
957{
958	/* sanity checks */
959	if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
960	    lc->lro_mbuf_max == 0)) {
961		/* packet drop */
962		m_freem(mb);
963		return;
964	}
965
966	/* check if packet is not LRO capable */
967	if (__predict_false(mb->m_pkthdr.csum_flags == 0 ||
968	    (lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
969
970		/* input packet to network layer */
971		(*lc->ifp->if_input) (lc->ifp, mb);
972		return;
973	}
974
975	/* create sequence number */
976	lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
977	    (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
978	    (((uint64_t)mb->m_pkthdr.flowid) << 24) |
979	    ((uint64_t)lc->lro_mbuf_count);
980
981	/* enter mbuf */
982	lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
983
984	/* flush if array is full */
985	if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
986		tcp_lro_flush_all(lc);
987}
988
989/* end */
990