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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IPV4 GSO/GRO offload support
4 * Linux INET implementation
5 *
6 * TCPv4 GSO/GRO support
7 */
8
9#include <linux/indirect_call_wrapper.h>
10#include <linux/skbuff.h>
11#include <net/gro.h>
12#include <net/gso.h>
13#include <net/tcp.h>
14#include <net/protocol.h>
15
16static void tcp_gso_tstamp(struct sk_buff *skb, struct sk_buff *gso_skb,
17 unsigned int seq, unsigned int mss)
18{
19 u32 flags = skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP;
20 u32 ts_seq = skb_shinfo(gso_skb)->tskey;
21
22 while (skb) {
23 if (before(ts_seq, seq + mss)) {
24 skb_shinfo(skb)->tx_flags |= flags;
25 skb_shinfo(skb)->tskey = ts_seq;
26 return;
27 }
28
29 skb = skb->next;
30 seq += mss;
31 }
32}
33
34static void __tcpv4_gso_segment_csum(struct sk_buff *seg,
35 __be32 *oldip, __be32 newip,
36 __be16 *oldport, __be16 newport)
37{
38 struct tcphdr *th;
39 struct iphdr *iph;
40
41 if (*oldip == newip && *oldport == newport)
42 return;
43
44 th = tcp_hdr(seg);
45 iph = ip_hdr(seg);
46
47 inet_proto_csum_replace4(&th->check, seg, *oldip, newip, true);
48 inet_proto_csum_replace2(&th->check, seg, *oldport, newport, false);
49 *oldport = newport;
50
51 csum_replace4(&iph->check, *oldip, newip);
52 *oldip = newip;
53}
54
55static struct sk_buff *__tcpv4_gso_segment_list_csum(struct sk_buff *segs)
56{
57 const struct tcphdr *th;
58 const struct iphdr *iph;
59 struct sk_buff *seg;
60 struct tcphdr *th2;
61 struct iphdr *iph2;
62
63 seg = segs;
64 th = tcp_hdr(seg);
65 iph = ip_hdr(seg);
66 th2 = tcp_hdr(seg->next);
67 iph2 = ip_hdr(seg->next);
68
69 if (!(*(const u32 *)&th->source ^ *(const u32 *)&th2->source) &&
70 iph->daddr == iph2->daddr && iph->saddr == iph2->saddr)
71 return segs;
72
73 while ((seg = seg->next)) {
74 th2 = tcp_hdr(seg);
75 iph2 = ip_hdr(seg);
76
77 __tcpv4_gso_segment_csum(seg,
78 &iph2->saddr, iph->saddr,
79 &th2->source, th->source);
80 __tcpv4_gso_segment_csum(seg,
81 &iph2->daddr, iph->daddr,
82 &th2->dest, th->dest);
83 }
84
85 return segs;
86}
87
88static struct sk_buff *__tcp4_gso_segment_list(struct sk_buff *skb,
89 netdev_features_t features)
90{
91 skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
92 if (IS_ERR(skb))
93 return skb;
94
95 return __tcpv4_gso_segment_list_csum(skb);
96}
97
98static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
99 netdev_features_t features)
100{
101 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4))
102 return ERR_PTR(-EINVAL);
103
104 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
105 return ERR_PTR(-EINVAL);
106
107 if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) {
108 struct tcphdr *th = tcp_hdr(skb);
109
110 if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size)
111 return __tcp4_gso_segment_list(skb, features);
112
113 skb->ip_summed = CHECKSUM_NONE;
114 }
115
116 if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
117 const struct iphdr *iph = ip_hdr(skb);
118 struct tcphdr *th = tcp_hdr(skb);
119
120 /* Set up checksum pseudo header, usually expect stack to
121 * have done this already.
122 */
123
124 th->check = 0;
125 skb->ip_summed = CHECKSUM_PARTIAL;
126 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
127 }
128
129 return tcp_gso_segment(skb, features);
130}
131
132struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
133 netdev_features_t features)
134{
135 struct sk_buff *segs = ERR_PTR(-EINVAL);
136 unsigned int sum_truesize = 0;
137 struct tcphdr *th;
138 unsigned int thlen;
139 unsigned int seq;
140 unsigned int oldlen;
141 unsigned int mss;
142 struct sk_buff *gso_skb = skb;
143 __sum16 newcheck;
144 bool ooo_okay, copy_destructor;
145 __wsum delta;
146
147 th = tcp_hdr(skb);
148 thlen = th->doff * 4;
149 if (thlen < sizeof(*th))
150 goto out;
151
152 if (unlikely(skb_checksum_start(skb) != skb_transport_header(skb)))
153 goto out;
154
155 if (!pskb_may_pull(skb, thlen))
156 goto out;
157
158 oldlen = ~skb->len;
159 __skb_pull(skb, thlen);
160
161 mss = skb_shinfo(skb)->gso_size;
162 if (unlikely(skb->len <= mss))
163 goto out;
164
165 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
166 /* Packet is from an untrusted source, reset gso_segs. */
167
168 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
169
170 segs = NULL;
171 goto out;
172 }
173
174 copy_destructor = gso_skb->destructor == tcp_wfree;
175 ooo_okay = gso_skb->ooo_okay;
176 /* All segments but the first should have ooo_okay cleared */
177 skb->ooo_okay = 0;
178
179 segs = skb_segment(skb, features);
180 if (IS_ERR(segs))
181 goto out;
182
183 /* Only first segment might have ooo_okay set */
184 segs->ooo_okay = ooo_okay;
185
186 /* GSO partial and frag_list segmentation only requires splitting
187 * the frame into an MSS multiple and possibly a remainder, both
188 * cases return a GSO skb. So update the mss now.
189 */
190 if (skb_is_gso(segs))
191 mss *= skb_shinfo(segs)->gso_segs;
192
193 delta = (__force __wsum)htonl(oldlen + thlen + mss);
194
195 skb = segs;
196 th = tcp_hdr(skb);
197 seq = ntohl(th->seq);
198
199 if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP))
200 tcp_gso_tstamp(segs, gso_skb, seq, mss);
201
202 newcheck = ~csum_fold(csum_add(csum_unfold(th->check), delta));
203
204 while (skb->next) {
205 th->fin = th->psh = 0;
206 th->check = newcheck;
207
208 if (skb->ip_summed == CHECKSUM_PARTIAL)
209 gso_reset_checksum(skb, ~th->check);
210 else
211 th->check = gso_make_checksum(skb, ~th->check);
212
213 seq += mss;
214 if (copy_destructor) {
215 skb->destructor = gso_skb->destructor;
216 skb->sk = gso_skb->sk;
217 sum_truesize += skb->truesize;
218 }
219 skb = skb->next;
220 th = tcp_hdr(skb);
221
222 th->seq = htonl(seq);
223 th->cwr = 0;
224 }
225
226 /* Following permits TCP Small Queues to work well with GSO :
227 * The callback to TCP stack will be called at the time last frag
228 * is freed at TX completion, and not right now when gso_skb
229 * is freed by GSO engine
230 */
231 if (copy_destructor) {
232 int delta;
233
234 swap(gso_skb->sk, skb->sk);
235 swap(gso_skb->destructor, skb->destructor);
236 sum_truesize += skb->truesize;
237 delta = sum_truesize - gso_skb->truesize;
238 /* In some pathological cases, delta can be negative.
239 * We need to either use refcount_add() or refcount_sub_and_test()
240 */
241 if (likely(delta >= 0))
242 refcount_add(delta, &skb->sk->sk_wmem_alloc);
243 else
244 WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
245 }
246
247 delta = (__force __wsum)htonl(oldlen +
248 (skb_tail_pointer(skb) -
249 skb_transport_header(skb)) +
250 skb->data_len);
251 th->check = ~csum_fold(csum_add(csum_unfold(th->check), delta));
252 if (skb->ip_summed == CHECKSUM_PARTIAL)
253 gso_reset_checksum(skb, ~th->check);
254 else
255 th->check = gso_make_checksum(skb, ~th->check);
256out:
257 return segs;
258}
259
260struct sk_buff *tcp_gro_lookup(struct list_head *head, struct tcphdr *th)
261{
262 struct tcphdr *th2;
263 struct sk_buff *p;
264
265 list_for_each_entry(p, head, list) {
266 if (!NAPI_GRO_CB(p)->same_flow)
267 continue;
268
269 th2 = tcp_hdr(p);
270 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
271 NAPI_GRO_CB(p)->same_flow = 0;
272 continue;
273 }
274
275 return p;
276 }
277
278 return NULL;
279}
280
281struct tcphdr *tcp_gro_pull_header(struct sk_buff *skb)
282{
283 unsigned int thlen, hlen, off;
284 struct tcphdr *th;
285
286 off = skb_gro_offset(skb);
287 hlen = off + sizeof(*th);
288 th = skb_gro_header(skb, hlen, off);
289 if (unlikely(!th))
290 return NULL;
291
292 thlen = th->doff * 4;
293 if (thlen < sizeof(*th))
294 return NULL;
295
296 hlen = off + thlen;
297 if (!skb_gro_may_pull(skb, hlen)) {
298 th = skb_gro_header_slow(skb, hlen, off);
299 if (unlikely(!th))
300 return NULL;
301 }
302
303 skb_gro_pull(skb, thlen);
304
305 return th;
306}
307
308struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb,
309 struct tcphdr *th)
310{
311 unsigned int thlen = th->doff * 4;
312 struct sk_buff *pp = NULL;
313 struct sk_buff *p;
314 struct tcphdr *th2;
315 unsigned int len;
316 __be32 flags;
317 unsigned int mss = 1;
318 int flush = 1;
319 int i;
320
321 len = skb_gro_len(skb);
322 flags = tcp_flag_word(th);
323
324 p = tcp_gro_lookup(head, th);
325 if (!p)
326 goto out_check_final;
327
328 th2 = tcp_hdr(p);
329 flush = (__force int)(flags & TCP_FLAG_CWR);
330 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
331 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
332 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
333 for (i = sizeof(*th); i < thlen; i += 4)
334 flush |= *(u32 *)((u8 *)th + i) ^
335 *(u32 *)((u8 *)th2 + i);
336
337 flush |= gro_receive_network_flush(th, th2, p);
338
339 mss = skb_shinfo(p)->gso_size;
340
341 /* If skb is a GRO packet, make sure its gso_size matches prior packet mss.
342 * If it is a single frame, do not aggregate it if its length
343 * is bigger than our mss.
344 */
345 if (unlikely(skb_is_gso(skb)))
346 flush |= (mss != skb_shinfo(skb)->gso_size);
347 else
348 flush |= (len - 1) >= mss;
349
350 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
351 flush |= skb_cmp_decrypted(p, skb);
352
353 if (unlikely(NAPI_GRO_CB(p)->is_flist)) {
354 flush |= (__force int)(flags ^ tcp_flag_word(th2));
355 flush |= skb->ip_summed != p->ip_summed;
356 flush |= skb->csum_level != p->csum_level;
357 flush |= NAPI_GRO_CB(p)->count >= 64;
358
359 if (flush || skb_gro_receive_list(p, skb))
360 mss = 1;
361
362 goto out_check_final;
363 }
364
365 if (flush || skb_gro_receive(p, skb)) {
366 mss = 1;
367 goto out_check_final;
368 }
369
370 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
371
372out_check_final:
373 /* Force a flush if last segment is smaller than mss. */
374 if (unlikely(skb_is_gso(skb)))
375 flush = len != NAPI_GRO_CB(skb)->count * skb_shinfo(skb)->gso_size;
376 else
377 flush = len < mss;
378
379 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
380 TCP_FLAG_RST | TCP_FLAG_SYN |
381 TCP_FLAG_FIN));
382
383 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
384 pp = p;
385
386 NAPI_GRO_CB(skb)->flush |= (flush != 0);
387
388 return pp;
389}
390
391void tcp_gro_complete(struct sk_buff *skb)
392{
393 struct tcphdr *th = tcp_hdr(skb);
394 struct skb_shared_info *shinfo;
395
396 if (skb->encapsulation)
397 skb->inner_transport_header = skb->transport_header;
398
399 skb->csum_start = (unsigned char *)th - skb->head;
400 skb->csum_offset = offsetof(struct tcphdr, check);
401 skb->ip_summed = CHECKSUM_PARTIAL;
402
403 shinfo = skb_shinfo(skb);
404 shinfo->gso_segs = NAPI_GRO_CB(skb)->count;
405
406 if (th->cwr)
407 shinfo->gso_type |= SKB_GSO_TCP_ECN;
408}
409EXPORT_SYMBOL(tcp_gro_complete);
410
411static void tcp4_check_fraglist_gro(struct list_head *head, struct sk_buff *skb,
412 struct tcphdr *th)
413{
414 const struct iphdr *iph;
415 struct sk_buff *p;
416 struct sock *sk;
417 struct net *net;
418 int iif, sdif;
419
420 if (likely(!(skb->dev->features & NETIF_F_GRO_FRAGLIST)))
421 return;
422
423 p = tcp_gro_lookup(head, th);
424 if (p) {
425 NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist;
426 return;
427 }
428
429 inet_get_iif_sdif(skb, &iif, &sdif);
430 iph = skb_gro_network_header(skb);
431 net = dev_net(skb->dev);
432 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
433 iph->saddr, th->source,
434 iph->daddr, ntohs(th->dest),
435 iif, sdif);
436 NAPI_GRO_CB(skb)->is_flist = !sk;
437 if (sk)
438 sock_put(sk);
439}
440
441INDIRECT_CALLABLE_SCOPE
442struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)
443{
444 struct tcphdr *th;
445
446 /* Don't bother verifying checksum if we're going to flush anyway. */
447 if (!NAPI_GRO_CB(skb)->flush &&
448 skb_gro_checksum_validate(skb, IPPROTO_TCP,
449 inet_gro_compute_pseudo))
450 goto flush;
451
452 th = tcp_gro_pull_header(skb);
453 if (!th)
454 goto flush;
455
456 tcp4_check_fraglist_gro(head, skb, th);
457
458 return tcp_gro_receive(head, skb, th);
459
460flush:
461 NAPI_GRO_CB(skb)->flush = 1;
462 return NULL;
463}
464
465INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
466{
467 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
468 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
469 struct tcphdr *th = tcp_hdr(skb);
470
471 if (unlikely(NAPI_GRO_CB(skb)->is_flist)) {
472 skb_shinfo(skb)->gso_type |= SKB_GSO_FRAGLIST | SKB_GSO_TCPV4;
473 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
474
475 __skb_incr_checksum_unnecessary(skb);
476
477 return 0;
478 }
479
480 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
481 iph->daddr, 0);
482
483 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4 |
484 (NAPI_GRO_CB(skb)->ip_fixedid * SKB_GSO_TCP_FIXEDID);
485
486 tcp_gro_complete(skb);
487 return 0;
488}
489
490int __init tcpv4_offload_init(void)
491{
492 net_hotdata.tcpv4_offload = (struct net_offload) {
493 .callbacks = {
494 .gso_segment = tcp4_gso_segment,
495 .gro_receive = tcp4_gro_receive,
496 .gro_complete = tcp4_gro_complete,
497 },
498 };
499 return inet_add_offload(&net_hotdata.tcpv4_offload, IPPROTO_TCP);
500}
1/*
2 * IPV4 GSO/GRO offload support
3 * Linux INET implementation
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * TCPv4 GSO/GRO support
11 */
12
13#include <linux/skbuff.h>
14#include <net/tcp.h>
15#include <net/protocol.h>
16
17static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
18 unsigned int seq, unsigned int mss)
19{
20 while (skb) {
21 if (before(ts_seq, seq + mss)) {
22 skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP;
23 skb_shinfo(skb)->tskey = ts_seq;
24 return;
25 }
26
27 skb = skb->next;
28 seq += mss;
29 }
30}
31
32static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
33 netdev_features_t features)
34{
35 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
36 return ERR_PTR(-EINVAL);
37
38 if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
39 const struct iphdr *iph = ip_hdr(skb);
40 struct tcphdr *th = tcp_hdr(skb);
41
42 /* Set up checksum pseudo header, usually expect stack to
43 * have done this already.
44 */
45
46 th->check = 0;
47 skb->ip_summed = CHECKSUM_PARTIAL;
48 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
49 }
50
51 return tcp_gso_segment(skb, features);
52}
53
54struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
55 netdev_features_t features)
56{
57 struct sk_buff *segs = ERR_PTR(-EINVAL);
58 unsigned int sum_truesize = 0;
59 struct tcphdr *th;
60 unsigned int thlen;
61 unsigned int seq;
62 __be32 delta;
63 unsigned int oldlen;
64 unsigned int mss;
65 struct sk_buff *gso_skb = skb;
66 __sum16 newcheck;
67 bool ooo_okay, copy_destructor;
68
69 th = tcp_hdr(skb);
70 thlen = th->doff * 4;
71 if (thlen < sizeof(*th))
72 goto out;
73
74 if (!pskb_may_pull(skb, thlen))
75 goto out;
76
77 oldlen = (u16)~skb->len;
78 __skb_pull(skb, thlen);
79
80 mss = skb_shinfo(skb)->gso_size;
81 if (unlikely(skb->len <= mss))
82 goto out;
83
84 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
85 /* Packet is from an untrusted source, reset gso_segs. */
86
87 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
88
89 segs = NULL;
90 goto out;
91 }
92
93 copy_destructor = gso_skb->destructor == tcp_wfree;
94 ooo_okay = gso_skb->ooo_okay;
95 /* All segments but the first should have ooo_okay cleared */
96 skb->ooo_okay = 0;
97
98 segs = skb_segment(skb, features);
99 if (IS_ERR(segs))
100 goto out;
101
102 /* Only first segment might have ooo_okay set */
103 segs->ooo_okay = ooo_okay;
104
105 /* GSO partial and frag_list segmentation only requires splitting
106 * the frame into an MSS multiple and possibly a remainder, both
107 * cases return a GSO skb. So update the mss now.
108 */
109 if (skb_is_gso(segs))
110 mss *= skb_shinfo(segs)->gso_segs;
111
112 delta = htonl(oldlen + (thlen + mss));
113
114 skb = segs;
115 th = tcp_hdr(skb);
116 seq = ntohl(th->seq);
117
118 if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
119 tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
120
121 newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
122 (__force u32)delta));
123
124 while (skb->next) {
125 th->fin = th->psh = 0;
126 th->check = newcheck;
127
128 if (skb->ip_summed == CHECKSUM_PARTIAL)
129 gso_reset_checksum(skb, ~th->check);
130 else
131 th->check = gso_make_checksum(skb, ~th->check);
132
133 seq += mss;
134 if (copy_destructor) {
135 skb->destructor = gso_skb->destructor;
136 skb->sk = gso_skb->sk;
137 sum_truesize += skb->truesize;
138 }
139 skb = skb->next;
140 th = tcp_hdr(skb);
141
142 th->seq = htonl(seq);
143 th->cwr = 0;
144 }
145
146 /* Following permits TCP Small Queues to work well with GSO :
147 * The callback to TCP stack will be called at the time last frag
148 * is freed at TX completion, and not right now when gso_skb
149 * is freed by GSO engine
150 */
151 if (copy_destructor) {
152 swap(gso_skb->sk, skb->sk);
153 swap(gso_skb->destructor, skb->destructor);
154 sum_truesize += skb->truesize;
155 atomic_add(sum_truesize - gso_skb->truesize,
156 &skb->sk->sk_wmem_alloc);
157 }
158
159 delta = htonl(oldlen + (skb_tail_pointer(skb) -
160 skb_transport_header(skb)) +
161 skb->data_len);
162 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
163 (__force u32)delta));
164 if (skb->ip_summed == CHECKSUM_PARTIAL)
165 gso_reset_checksum(skb, ~th->check);
166 else
167 th->check = gso_make_checksum(skb, ~th->check);
168out:
169 return segs;
170}
171
172struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
173{
174 struct sk_buff **pp = NULL;
175 struct sk_buff *p;
176 struct tcphdr *th;
177 struct tcphdr *th2;
178 unsigned int len;
179 unsigned int thlen;
180 __be32 flags;
181 unsigned int mss = 1;
182 unsigned int hlen;
183 unsigned int off;
184 int flush = 1;
185 int i;
186
187 off = skb_gro_offset(skb);
188 hlen = off + sizeof(*th);
189 th = skb_gro_header_fast(skb, off);
190 if (skb_gro_header_hard(skb, hlen)) {
191 th = skb_gro_header_slow(skb, hlen, off);
192 if (unlikely(!th))
193 goto out;
194 }
195
196 thlen = th->doff * 4;
197 if (thlen < sizeof(*th))
198 goto out;
199
200 hlen = off + thlen;
201 if (skb_gro_header_hard(skb, hlen)) {
202 th = skb_gro_header_slow(skb, hlen, off);
203 if (unlikely(!th))
204 goto out;
205 }
206
207 skb_gro_pull(skb, thlen);
208
209 len = skb_gro_len(skb);
210 flags = tcp_flag_word(th);
211
212 for (; (p = *head); head = &p->next) {
213 if (!NAPI_GRO_CB(p)->same_flow)
214 continue;
215
216 th2 = tcp_hdr(p);
217
218 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
219 NAPI_GRO_CB(p)->same_flow = 0;
220 continue;
221 }
222
223 goto found;
224 }
225
226 goto out_check_final;
227
228found:
229 /* Include the IP ID check below from the inner most IP hdr */
230 flush = NAPI_GRO_CB(p)->flush;
231 flush |= (__force int)(flags & TCP_FLAG_CWR);
232 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
233 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
234 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
235 for (i = sizeof(*th); i < thlen; i += 4)
236 flush |= *(u32 *)((u8 *)th + i) ^
237 *(u32 *)((u8 *)th2 + i);
238
239 /* When we receive our second frame we can made a decision on if we
240 * continue this flow as an atomic flow with a fixed ID or if we use
241 * an incrementing ID.
242 */
243 if (NAPI_GRO_CB(p)->flush_id != 1 ||
244 NAPI_GRO_CB(p)->count != 1 ||
245 !NAPI_GRO_CB(p)->is_atomic)
246 flush |= NAPI_GRO_CB(p)->flush_id;
247 else
248 NAPI_GRO_CB(p)->is_atomic = false;
249
250 mss = skb_shinfo(p)->gso_size;
251
252 flush |= (len - 1) >= mss;
253 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
254
255 if (flush || skb_gro_receive(head, skb)) {
256 mss = 1;
257 goto out_check_final;
258 }
259
260 p = *head;
261 th2 = tcp_hdr(p);
262 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
263
264out_check_final:
265 flush = len < mss;
266 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
267 TCP_FLAG_RST | TCP_FLAG_SYN |
268 TCP_FLAG_FIN));
269
270 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
271 pp = head;
272
273out:
274 NAPI_GRO_CB(skb)->flush |= (flush != 0);
275
276 return pp;
277}
278
279int tcp_gro_complete(struct sk_buff *skb)
280{
281 struct tcphdr *th = tcp_hdr(skb);
282
283 skb->csum_start = (unsigned char *)th - skb->head;
284 skb->csum_offset = offsetof(struct tcphdr, check);
285 skb->ip_summed = CHECKSUM_PARTIAL;
286
287 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
288
289 if (th->cwr)
290 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
291
292 return 0;
293}
294EXPORT_SYMBOL(tcp_gro_complete);
295
296static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
297{
298 /* Don't bother verifying checksum if we're going to flush anyway. */
299 if (!NAPI_GRO_CB(skb)->flush &&
300 skb_gro_checksum_validate(skb, IPPROTO_TCP,
301 inet_gro_compute_pseudo)) {
302 NAPI_GRO_CB(skb)->flush = 1;
303 return NULL;
304 }
305
306 return tcp_gro_receive(head, skb);
307}
308
309static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
310{
311 const struct iphdr *iph = ip_hdr(skb);
312 struct tcphdr *th = tcp_hdr(skb);
313
314 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
315 iph->daddr, 0);
316 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
317
318 if (NAPI_GRO_CB(skb)->is_atomic)
319 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;
320
321 return tcp_gro_complete(skb);
322}
323
324static const struct net_offload tcpv4_offload = {
325 .callbacks = {
326 .gso_segment = tcp4_gso_segment,
327 .gro_receive = tcp4_gro_receive,
328 .gro_complete = tcp4_gro_complete,
329 },
330};
331
332int __init tcpv4_offload_init(void)
333{
334 return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
335}