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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/tcp.h>
12#include <net/protocol.h>
13
14static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
15 unsigned int seq, unsigned int mss)
16{
17 while (skb) {
18 if (before(ts_seq, seq + mss)) {
19 skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP;
20 skb_shinfo(skb)->tskey = ts_seq;
21 return;
22 }
23
24 skb = skb->next;
25 seq += mss;
26 }
27}
28
29static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
30 netdev_features_t features)
31{
32 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4))
33 return ERR_PTR(-EINVAL);
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 int delta;
153
154 swap(gso_skb->sk, skb->sk);
155 swap(gso_skb->destructor, skb->destructor);
156 sum_truesize += skb->truesize;
157 delta = sum_truesize - gso_skb->truesize;
158 /* In some pathological cases, delta can be negative.
159 * We need to either use refcount_add() or refcount_sub_and_test()
160 */
161 if (likely(delta >= 0))
162 refcount_add(delta, &skb->sk->sk_wmem_alloc);
163 else
164 WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
165 }
166
167 delta = htonl(oldlen + (skb_tail_pointer(skb) -
168 skb_transport_header(skb)) +
169 skb->data_len);
170 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
171 (__force u32)delta));
172 if (skb->ip_summed == CHECKSUM_PARTIAL)
173 gso_reset_checksum(skb, ~th->check);
174 else
175 th->check = gso_make_checksum(skb, ~th->check);
176out:
177 return segs;
178}
179
180struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
181{
182 struct sk_buff *pp = NULL;
183 struct sk_buff *p;
184 struct tcphdr *th;
185 struct tcphdr *th2;
186 unsigned int len;
187 unsigned int thlen;
188 __be32 flags;
189 unsigned int mss = 1;
190 unsigned int hlen;
191 unsigned int off;
192 int flush = 1;
193 int i;
194
195 off = skb_gro_offset(skb);
196 hlen = off + sizeof(*th);
197 th = skb_gro_header_fast(skb, off);
198 if (skb_gro_header_hard(skb, hlen)) {
199 th = skb_gro_header_slow(skb, hlen, off);
200 if (unlikely(!th))
201 goto out;
202 }
203
204 thlen = th->doff * 4;
205 if (thlen < sizeof(*th))
206 goto out;
207
208 hlen = off + thlen;
209 if (skb_gro_header_hard(skb, hlen)) {
210 th = skb_gro_header_slow(skb, hlen, off);
211 if (unlikely(!th))
212 goto out;
213 }
214
215 skb_gro_pull(skb, thlen);
216
217 len = skb_gro_len(skb);
218 flags = tcp_flag_word(th);
219
220 list_for_each_entry(p, head, list) {
221 if (!NAPI_GRO_CB(p)->same_flow)
222 continue;
223
224 th2 = tcp_hdr(p);
225
226 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
227 NAPI_GRO_CB(p)->same_flow = 0;
228 continue;
229 }
230
231 goto found;
232 }
233 p = NULL;
234 goto out_check_final;
235
236found:
237 /* Include the IP ID check below from the inner most IP hdr */
238 flush = NAPI_GRO_CB(p)->flush;
239 flush |= (__force int)(flags & TCP_FLAG_CWR);
240 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
241 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
242 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
243 for (i = sizeof(*th); i < thlen; i += 4)
244 flush |= *(u32 *)((u8 *)th + i) ^
245 *(u32 *)((u8 *)th2 + i);
246
247 /* When we receive our second frame we can made a decision on if we
248 * continue this flow as an atomic flow with a fixed ID or if we use
249 * an incrementing ID.
250 */
251 if (NAPI_GRO_CB(p)->flush_id != 1 ||
252 NAPI_GRO_CB(p)->count != 1 ||
253 !NAPI_GRO_CB(p)->is_atomic)
254 flush |= NAPI_GRO_CB(p)->flush_id;
255 else
256 NAPI_GRO_CB(p)->is_atomic = false;
257
258 mss = skb_shinfo(p)->gso_size;
259
260 flush |= (len - 1) >= mss;
261 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
262#ifdef CONFIG_TLS_DEVICE
263 flush |= p->decrypted ^ skb->decrypted;
264#endif
265
266 if (flush || skb_gro_receive(p, skb)) {
267 mss = 1;
268 goto out_check_final;
269 }
270
271 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
272
273out_check_final:
274 flush = len < mss;
275 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
276 TCP_FLAG_RST | TCP_FLAG_SYN |
277 TCP_FLAG_FIN));
278
279 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
280 pp = p;
281
282out:
283 NAPI_GRO_CB(skb)->flush |= (flush != 0);
284
285 return pp;
286}
287
288int tcp_gro_complete(struct sk_buff *skb)
289{
290 struct tcphdr *th = tcp_hdr(skb);
291
292 skb->csum_start = (unsigned char *)th - skb->head;
293 skb->csum_offset = offsetof(struct tcphdr, check);
294 skb->ip_summed = CHECKSUM_PARTIAL;
295
296 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
297
298 if (th->cwr)
299 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
300
301 if (skb->encapsulation)
302 skb->inner_transport_header = skb->transport_header;
303
304 return 0;
305}
306EXPORT_SYMBOL(tcp_gro_complete);
307
308INDIRECT_CALLABLE_SCOPE
309struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)
310{
311 /* Don't bother verifying checksum if we're going to flush anyway. */
312 if (!NAPI_GRO_CB(skb)->flush &&
313 skb_gro_checksum_validate(skb, IPPROTO_TCP,
314 inet_gro_compute_pseudo)) {
315 NAPI_GRO_CB(skb)->flush = 1;
316 return NULL;
317 }
318
319 return tcp_gro_receive(head, skb);
320}
321
322INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
323{
324 const struct iphdr *iph = ip_hdr(skb);
325 struct tcphdr *th = tcp_hdr(skb);
326
327 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
328 iph->daddr, 0);
329 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
330
331 if (NAPI_GRO_CB(skb)->is_atomic)
332 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;
333
334 return tcp_gro_complete(skb);
335}
336
337static const struct net_offload tcpv4_offload = {
338 .callbacks = {
339 .gso_segment = tcp4_gso_segment,
340 .gro_receive = tcp4_gro_receive,
341 .gro_complete = tcp4_gro_complete,
342 },
343};
344
345int __init tcpv4_offload_init(void)
346{
347 return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
348}
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
17struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
18 netdev_features_t features)
19{
20 struct sk_buff *segs = ERR_PTR(-EINVAL);
21 unsigned int sum_truesize = 0;
22 struct tcphdr *th;
23 unsigned int thlen;
24 unsigned int seq;
25 __be32 delta;
26 unsigned int oldlen;
27 unsigned int mss;
28 struct sk_buff *gso_skb = skb;
29 __sum16 newcheck;
30 bool ooo_okay, copy_destructor;
31
32 if (!pskb_may_pull(skb, sizeof(*th)))
33 goto out;
34
35 th = tcp_hdr(skb);
36 thlen = th->doff * 4;
37 if (thlen < sizeof(*th))
38 goto out;
39
40 if (!pskb_may_pull(skb, thlen))
41 goto out;
42
43 oldlen = (u16)~skb->len;
44 __skb_pull(skb, thlen);
45
46 mss = tcp_skb_mss(skb);
47 if (unlikely(skb->len <= mss))
48 goto out;
49
50 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
51 /* Packet is from an untrusted source, reset gso_segs. */
52 int type = skb_shinfo(skb)->gso_type;
53
54 if (unlikely(type &
55 ~(SKB_GSO_TCPV4 |
56 SKB_GSO_DODGY |
57 SKB_GSO_TCP_ECN |
58 SKB_GSO_TCPV6 |
59 SKB_GSO_GRE |
60 SKB_GSO_IPIP |
61 SKB_GSO_SIT |
62 SKB_GSO_MPLS |
63 SKB_GSO_UDP_TUNNEL |
64 0) ||
65 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
66 goto out;
67
68 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
69
70 segs = NULL;
71 goto out;
72 }
73
74 copy_destructor = gso_skb->destructor == tcp_wfree;
75 ooo_okay = gso_skb->ooo_okay;
76 /* All segments but the first should have ooo_okay cleared */
77 skb->ooo_okay = 0;
78
79 segs = skb_segment(skb, features);
80 if (IS_ERR(segs))
81 goto out;
82
83 /* Only first segment might have ooo_okay set */
84 segs->ooo_okay = ooo_okay;
85
86 delta = htonl(oldlen + (thlen + mss));
87
88 skb = segs;
89 th = tcp_hdr(skb);
90 seq = ntohl(th->seq);
91
92 newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
93 (__force u32)delta));
94
95 do {
96 th->fin = th->psh = 0;
97 th->check = newcheck;
98
99 if (skb->ip_summed != CHECKSUM_PARTIAL)
100 th->check =
101 csum_fold(csum_partial(skb_transport_header(skb),
102 thlen, skb->csum));
103
104 seq += mss;
105 if (copy_destructor) {
106 skb->destructor = gso_skb->destructor;
107 skb->sk = gso_skb->sk;
108 sum_truesize += skb->truesize;
109 }
110 skb = skb->next;
111 th = tcp_hdr(skb);
112
113 th->seq = htonl(seq);
114 th->cwr = 0;
115 } while (skb->next);
116
117 /* Following permits TCP Small Queues to work well with GSO :
118 * The callback to TCP stack will be called at the time last frag
119 * is freed at TX completion, and not right now when gso_skb
120 * is freed by GSO engine
121 */
122 if (copy_destructor) {
123 swap(gso_skb->sk, skb->sk);
124 swap(gso_skb->destructor, skb->destructor);
125 sum_truesize += skb->truesize;
126 atomic_add(sum_truesize - gso_skb->truesize,
127 &skb->sk->sk_wmem_alloc);
128 }
129
130 delta = htonl(oldlen + (skb_tail_pointer(skb) -
131 skb_transport_header(skb)) +
132 skb->data_len);
133 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
134 (__force u32)delta));
135 if (skb->ip_summed != CHECKSUM_PARTIAL)
136 th->check = csum_fold(csum_partial(skb_transport_header(skb),
137 thlen, skb->csum));
138out:
139 return segs;
140}
141
142struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
143{
144 struct sk_buff **pp = NULL;
145 struct sk_buff *p;
146 struct tcphdr *th;
147 struct tcphdr *th2;
148 unsigned int len;
149 unsigned int thlen;
150 __be32 flags;
151 unsigned int mss = 1;
152 unsigned int hlen;
153 unsigned int off;
154 int flush = 1;
155 int i;
156
157 off = skb_gro_offset(skb);
158 hlen = off + sizeof(*th);
159 th = skb_gro_header_fast(skb, off);
160 if (skb_gro_header_hard(skb, hlen)) {
161 th = skb_gro_header_slow(skb, hlen, off);
162 if (unlikely(!th))
163 goto out;
164 }
165
166 thlen = th->doff * 4;
167 if (thlen < sizeof(*th))
168 goto out;
169
170 hlen = off + thlen;
171 if (skb_gro_header_hard(skb, hlen)) {
172 th = skb_gro_header_slow(skb, hlen, off);
173 if (unlikely(!th))
174 goto out;
175 }
176
177 skb_gro_pull(skb, thlen);
178
179 len = skb_gro_len(skb);
180 flags = tcp_flag_word(th);
181
182 for (; (p = *head); head = &p->next) {
183 if (!NAPI_GRO_CB(p)->same_flow)
184 continue;
185
186 th2 = tcp_hdr(p);
187
188 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
189 NAPI_GRO_CB(p)->same_flow = 0;
190 continue;
191 }
192
193 goto found;
194 }
195
196 goto out_check_final;
197
198found:
199 /* Include the IP ID check below from the inner most IP hdr */
200 flush = NAPI_GRO_CB(p)->flush | NAPI_GRO_CB(p)->flush_id;
201 flush |= (__force int)(flags & TCP_FLAG_CWR);
202 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
203 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
204 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
205 for (i = sizeof(*th); i < thlen; i += 4)
206 flush |= *(u32 *)((u8 *)th + i) ^
207 *(u32 *)((u8 *)th2 + i);
208
209 mss = tcp_skb_mss(p);
210
211 flush |= (len - 1) >= mss;
212 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
213
214 if (flush || skb_gro_receive(head, skb)) {
215 mss = 1;
216 goto out_check_final;
217 }
218
219 p = *head;
220 th2 = tcp_hdr(p);
221 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
222
223out_check_final:
224 flush = len < mss;
225 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
226 TCP_FLAG_RST | TCP_FLAG_SYN |
227 TCP_FLAG_FIN));
228
229 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
230 pp = head;
231
232out:
233 NAPI_GRO_CB(skb)->flush |= (flush != 0);
234
235 return pp;
236}
237
238int tcp_gro_complete(struct sk_buff *skb)
239{
240 struct tcphdr *th = tcp_hdr(skb);
241
242 skb->csum_start = (unsigned char *)th - skb->head;
243 skb->csum_offset = offsetof(struct tcphdr, check);
244 skb->ip_summed = CHECKSUM_PARTIAL;
245
246 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
247
248 if (th->cwr)
249 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
250
251 return 0;
252}
253EXPORT_SYMBOL(tcp_gro_complete);
254
255static int tcp_v4_gso_send_check(struct sk_buff *skb)
256{
257 const struct iphdr *iph;
258 struct tcphdr *th;
259
260 if (!pskb_may_pull(skb, sizeof(*th)))
261 return -EINVAL;
262
263 iph = ip_hdr(skb);
264 th = tcp_hdr(skb);
265
266 th->check = 0;
267 skb->ip_summed = CHECKSUM_PARTIAL;
268 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
269 return 0;
270}
271
272static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
273{
274 /* Use the IP hdr immediately proceeding for this transport */
275 const struct iphdr *iph = skb_gro_network_header(skb);
276 __wsum wsum;
277
278 /* Don't bother verifying checksum if we're going to flush anyway. */
279 if (NAPI_GRO_CB(skb)->flush)
280 goto skip_csum;
281
282 wsum = NAPI_GRO_CB(skb)->csum;
283
284 switch (skb->ip_summed) {
285 case CHECKSUM_NONE:
286 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb),
287 0);
288
289 /* fall through */
290
291 case CHECKSUM_COMPLETE:
292 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
293 wsum)) {
294 skb->ip_summed = CHECKSUM_UNNECESSARY;
295 break;
296 }
297
298 NAPI_GRO_CB(skb)->flush = 1;
299 return NULL;
300 }
301
302skip_csum:
303 return tcp_gro_receive(head, skb);
304}
305
306static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
307{
308 const struct iphdr *iph = ip_hdr(skb);
309 struct tcphdr *th = tcp_hdr(skb);
310
311 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
312 iph->daddr, 0);
313 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
314
315 return tcp_gro_complete(skb);
316}
317
318static const struct net_offload tcpv4_offload = {
319 .callbacks = {
320 .gso_send_check = tcp_v4_gso_send_check,
321 .gso_segment = tcp_gso_segment,
322 .gro_receive = tcp4_gro_receive,
323 .gro_complete = tcp4_gro_complete,
324 },
325};
326
327int __init tcpv4_offload_init(void)
328{
329 return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
330}