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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 int type = skb_shinfo(skb)->gso_type;
87
88 if (unlikely(type &
89 ~(SKB_GSO_TCPV4 |
90 SKB_GSO_DODGY |
91 SKB_GSO_TCP_ECN |
92 SKB_GSO_TCPV6 |
93 SKB_GSO_GRE |
94 SKB_GSO_GRE_CSUM |
95 SKB_GSO_IPIP |
96 SKB_GSO_SIT |
97 SKB_GSO_UDP_TUNNEL |
98 SKB_GSO_UDP_TUNNEL_CSUM |
99 SKB_GSO_TUNNEL_REMCSUM |
100 0) ||
101 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
102 goto out;
103
104 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
105
106 segs = NULL;
107 goto out;
108 }
109
110 copy_destructor = gso_skb->destructor == tcp_wfree;
111 ooo_okay = gso_skb->ooo_okay;
112 /* All segments but the first should have ooo_okay cleared */
113 skb->ooo_okay = 0;
114
115 segs = skb_segment(skb, features);
116 if (IS_ERR(segs))
117 goto out;
118
119 /* Only first segment might have ooo_okay set */
120 segs->ooo_okay = ooo_okay;
121
122 delta = htonl(oldlen + (thlen + mss));
123
124 skb = segs;
125 th = tcp_hdr(skb);
126 seq = ntohl(th->seq);
127
128 if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
129 tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
130
131 newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
132 (__force u32)delta));
133
134 do {
135 th->fin = th->psh = 0;
136 th->check = newcheck;
137
138 if (skb->ip_summed == CHECKSUM_PARTIAL)
139 gso_reset_checksum(skb, ~th->check);
140 else
141 th->check = gso_make_checksum(skb, ~th->check);
142
143 seq += mss;
144 if (copy_destructor) {
145 skb->destructor = gso_skb->destructor;
146 skb->sk = gso_skb->sk;
147 sum_truesize += skb->truesize;
148 }
149 skb = skb->next;
150 th = tcp_hdr(skb);
151
152 th->seq = htonl(seq);
153 th->cwr = 0;
154 } while (skb->next);
155
156 /* Following permits TCP Small Queues to work well with GSO :
157 * The callback to TCP stack will be called at the time last frag
158 * is freed at TX completion, and not right now when gso_skb
159 * is freed by GSO engine
160 */
161 if (copy_destructor) {
162 swap(gso_skb->sk, skb->sk);
163 swap(gso_skb->destructor, skb->destructor);
164 sum_truesize += skb->truesize;
165 atomic_add(sum_truesize - gso_skb->truesize,
166 &skb->sk->sk_wmem_alloc);
167 }
168
169 delta = htonl(oldlen + (skb_tail_pointer(skb) -
170 skb_transport_header(skb)) +
171 skb->data_len);
172 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
173 (__force u32)delta));
174 if (skb->ip_summed == CHECKSUM_PARTIAL)
175 gso_reset_checksum(skb, ~th->check);
176 else
177 th->check = gso_make_checksum(skb, ~th->check);
178out:
179 return segs;
180}
181
182struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
183{
184 struct sk_buff **pp = NULL;
185 struct sk_buff *p;
186 struct tcphdr *th;
187 struct tcphdr *th2;
188 unsigned int len;
189 unsigned int thlen;
190 __be32 flags;
191 unsigned int mss = 1;
192 unsigned int hlen;
193 unsigned int off;
194 int flush = 1;
195 int i;
196
197 off = skb_gro_offset(skb);
198 hlen = off + sizeof(*th);
199 th = skb_gro_header_fast(skb, off);
200 if (skb_gro_header_hard(skb, hlen)) {
201 th = skb_gro_header_slow(skb, hlen, off);
202 if (unlikely(!th))
203 goto out;
204 }
205
206 thlen = th->doff * 4;
207 if (thlen < sizeof(*th))
208 goto out;
209
210 hlen = off + thlen;
211 if (skb_gro_header_hard(skb, hlen)) {
212 th = skb_gro_header_slow(skb, hlen, off);
213 if (unlikely(!th))
214 goto out;
215 }
216
217 skb_gro_pull(skb, thlen);
218
219 len = skb_gro_len(skb);
220 flags = tcp_flag_word(th);
221
222 for (; (p = *head); head = &p->next) {
223 if (!NAPI_GRO_CB(p)->same_flow)
224 continue;
225
226 th2 = tcp_hdr(p);
227
228 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
229 NAPI_GRO_CB(p)->same_flow = 0;
230 continue;
231 }
232
233 goto found;
234 }
235
236 goto out_check_final;
237
238found:
239 /* Include the IP ID check below from the inner most IP hdr */
240 flush = NAPI_GRO_CB(p)->flush | NAPI_GRO_CB(p)->flush_id;
241 flush |= (__force int)(flags & TCP_FLAG_CWR);
242 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
243 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
244 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
245 for (i = sizeof(*th); i < thlen; i += 4)
246 flush |= *(u32 *)((u8 *)th + i) ^
247 *(u32 *)((u8 *)th2 + i);
248
249 mss = skb_shinfo(p)->gso_size;
250
251 flush |= (len - 1) >= mss;
252 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
253
254 if (flush || skb_gro_receive(head, skb)) {
255 mss = 1;
256 goto out_check_final;
257 }
258
259 p = *head;
260 th2 = tcp_hdr(p);
261 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
262
263out_check_final:
264 flush = len < mss;
265 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
266 TCP_FLAG_RST | TCP_FLAG_SYN |
267 TCP_FLAG_FIN));
268
269 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
270 pp = head;
271
272out:
273 NAPI_GRO_CB(skb)->flush |= (flush != 0);
274
275 return pp;
276}
277
278int tcp_gro_complete(struct sk_buff *skb)
279{
280 struct tcphdr *th = tcp_hdr(skb);
281
282 skb->csum_start = (unsigned char *)th - skb->head;
283 skb->csum_offset = offsetof(struct tcphdr, check);
284 skb->ip_summed = CHECKSUM_PARTIAL;
285
286 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
287
288 if (th->cwr)
289 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
290
291 return 0;
292}
293EXPORT_SYMBOL(tcp_gro_complete);
294
295static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
296{
297 /* Don't bother verifying checksum if we're going to flush anyway. */
298 if (!NAPI_GRO_CB(skb)->flush &&
299 skb_gro_checksum_validate(skb, IPPROTO_TCP,
300 inet_gro_compute_pseudo)) {
301 NAPI_GRO_CB(skb)->flush = 1;
302 return NULL;
303 }
304
305 return tcp_gro_receive(head, skb);
306}
307
308static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
309{
310 const struct iphdr *iph = ip_hdr(skb);
311 struct tcphdr *th = tcp_hdr(skb);
312
313 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
314 iph->daddr, 0);
315 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
316
317 return tcp_gro_complete(skb);
318}
319
320static const struct net_offload tcpv4_offload = {
321 .callbacks = {
322 .gso_segment = tcp4_gso_segment,
323 .gro_receive = tcp4_gro_receive,
324 .gro_complete = tcp4_gro_complete,
325 },
326};
327
328int __init tcpv4_offload_init(void)
329{
330 return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
331}