of: property: Disable fw_devlink DT support for X86
[linux-2.6-microblaze.git] / net / ipv4 / tcp_offload.c
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
14 static 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
29 static 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
54 struct 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);
176 out:
177         return segs;
178 }
179
180 struct 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
236 found:
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
273 out_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
282 out:
283         NAPI_GRO_CB(skb)->flush |= (flush != 0);
284
285         return pp;
286 }
287
288 int 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 }
306 EXPORT_SYMBOL(tcp_gro_complete);
307
308 INDIRECT_CALLABLE_SCOPE
309 struct 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
322 INDIRECT_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
337 static 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
345 int __init tcpv4_offload_init(void)
346 {
347         return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
348 }