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Commit | Line | Data |
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28850dc7 DB |
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 | ||
f066e2b0 WB |
17 | static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq, |
18 | unsigned int seq, unsigned int mss) | |
4ed2d765 WB |
19 | { |
20 | while (skb) { | |
f066e2b0 WB |
21 | if (before(ts_seq, seq + mss)) { |
22 | skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP; | |
4ed2d765 WB |
23 | skb_shinfo(skb)->tskey = ts_seq; |
24 | return; | |
25 | } | |
26 | ||
27 | skb = skb->next; | |
28 | seq += mss; | |
29 | } | |
30 | } | |
31 | ||
74abc20c ED |
32 | static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb, |
33 | netdev_features_t features) | |
d020f8f7 | 34 | { |
121d57af WB |
35 | if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)) |
36 | return ERR_PTR(-EINVAL); | |
37 | ||
d020f8f7 TH |
38 | if (!pskb_may_pull(skb, sizeof(struct tcphdr))) |
39 | return ERR_PTR(-EINVAL); | |
40 | ||
41 | if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) { | |
42 | const struct iphdr *iph = ip_hdr(skb); | |
43 | struct tcphdr *th = tcp_hdr(skb); | |
44 | ||
45 | /* Set up checksum pseudo header, usually expect stack to | |
46 | * have done this already. | |
47 | */ | |
48 | ||
49 | th->check = 0; | |
50 | skb->ip_summed = CHECKSUM_PARTIAL; | |
51 | __tcp_v4_send_check(skb, iph->saddr, iph->daddr); | |
52 | } | |
53 | ||
54 | return tcp_gso_segment(skb, features); | |
55 | } | |
56 | ||
28be6e07 | 57 | struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
28850dc7 DB |
58 | netdev_features_t features) |
59 | { | |
60 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
0d08c42c | 61 | unsigned int sum_truesize = 0; |
28850dc7 DB |
62 | struct tcphdr *th; |
63 | unsigned int thlen; | |
64 | unsigned int seq; | |
65 | __be32 delta; | |
66 | unsigned int oldlen; | |
67 | unsigned int mss; | |
68 | struct sk_buff *gso_skb = skb; | |
69 | __sum16 newcheck; | |
70 | bool ooo_okay, copy_destructor; | |
71 | ||
28850dc7 DB |
72 | th = tcp_hdr(skb); |
73 | thlen = th->doff * 4; | |
74 | if (thlen < sizeof(*th)) | |
75 | goto out; | |
76 | ||
77 | if (!pskb_may_pull(skb, thlen)) | |
78 | goto out; | |
79 | ||
80 | oldlen = (u16)~skb->len; | |
81 | __skb_pull(skb, thlen); | |
82 | ||
a7eea416 | 83 | mss = skb_shinfo(skb)->gso_size; |
28850dc7 DB |
84 | if (unlikely(skb->len <= mss)) |
85 | goto out; | |
86 | ||
87 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { | |
88 | /* Packet is from an untrusted source, reset gso_segs. */ | |
28850dc7 DB |
89 | |
90 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
91 | ||
92 | segs = NULL; | |
93 | goto out; | |
94 | } | |
95 | ||
96 | copy_destructor = gso_skb->destructor == tcp_wfree; | |
97 | ooo_okay = gso_skb->ooo_okay; | |
98 | /* All segments but the first should have ooo_okay cleared */ | |
99 | skb->ooo_okay = 0; | |
100 | ||
101 | segs = skb_segment(skb, features); | |
102 | if (IS_ERR(segs)) | |
103 | goto out; | |
104 | ||
105 | /* Only first segment might have ooo_okay set */ | |
106 | segs->ooo_okay = ooo_okay; | |
107 | ||
07b26c94 SK |
108 | /* GSO partial and frag_list segmentation only requires splitting |
109 | * the frame into an MSS multiple and possibly a remainder, both | |
110 | * cases return a GSO skb. So update the mss now. | |
111 | */ | |
112 | if (skb_is_gso(segs)) | |
113 | mss *= skb_shinfo(segs)->gso_segs; | |
114 | ||
28850dc7 DB |
115 | delta = htonl(oldlen + (thlen + mss)); |
116 | ||
117 | skb = segs; | |
118 | th = tcp_hdr(skb); | |
119 | seq = ntohl(th->seq); | |
120 | ||
4ed2d765 WB |
121 | if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP)) |
122 | tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss); | |
123 | ||
28850dc7 DB |
124 | newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + |
125 | (__force u32)delta)); | |
126 | ||
802ab55a | 127 | while (skb->next) { |
28850dc7 DB |
128 | th->fin = th->psh = 0; |
129 | th->check = newcheck; | |
130 | ||
08b64fcc AD |
131 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
132 | gso_reset_checksum(skb, ~th->check); | |
133 | else | |
e9c3a24b | 134 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
135 | |
136 | seq += mss; | |
137 | if (copy_destructor) { | |
138 | skb->destructor = gso_skb->destructor; | |
139 | skb->sk = gso_skb->sk; | |
0d08c42c | 140 | sum_truesize += skb->truesize; |
28850dc7 DB |
141 | } |
142 | skb = skb->next; | |
143 | th = tcp_hdr(skb); | |
144 | ||
145 | th->seq = htonl(seq); | |
146 | th->cwr = 0; | |
802ab55a | 147 | } |
28850dc7 DB |
148 | |
149 | /* Following permits TCP Small Queues to work well with GSO : | |
150 | * The callback to TCP stack will be called at the time last frag | |
151 | * is freed at TX completion, and not right now when gso_skb | |
152 | * is freed by GSO engine | |
153 | */ | |
154 | if (copy_destructor) { | |
7ec318fe ED |
155 | int delta; |
156 | ||
28850dc7 DB |
157 | swap(gso_skb->sk, skb->sk); |
158 | swap(gso_skb->destructor, skb->destructor); | |
0d08c42c | 159 | sum_truesize += skb->truesize; |
7ec318fe ED |
160 | delta = sum_truesize - gso_skb->truesize; |
161 | /* In some pathological cases, delta can be negative. | |
162 | * We need to either use refcount_add() or refcount_sub_and_test() | |
163 | */ | |
164 | if (likely(delta >= 0)) | |
165 | refcount_add(delta, &skb->sk->sk_wmem_alloc); | |
166 | else | |
167 | WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc)); | |
28850dc7 DB |
168 | } |
169 | ||
170 | delta = htonl(oldlen + (skb_tail_pointer(skb) - | |
171 | skb_transport_header(skb)) + | |
172 | skb->data_len); | |
173 | th->check = ~csum_fold((__force __wsum)((__force u32)th->check + | |
174 | (__force u32)delta)); | |
08b64fcc AD |
175 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
176 | gso_reset_checksum(skb, ~th->check); | |
177 | else | |
e9c3a24b | 178 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
179 | out: |
180 | return segs; | |
181 | } | |
28850dc7 DB |
182 | |
183 | struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
184 | { | |
185 | struct sk_buff **pp = NULL; | |
186 | struct sk_buff *p; | |
187 | struct tcphdr *th; | |
188 | struct tcphdr *th2; | |
189 | unsigned int len; | |
190 | unsigned int thlen; | |
191 | __be32 flags; | |
192 | unsigned int mss = 1; | |
193 | unsigned int hlen; | |
194 | unsigned int off; | |
195 | int flush = 1; | |
196 | int i; | |
197 | ||
198 | off = skb_gro_offset(skb); | |
199 | hlen = off + sizeof(*th); | |
200 | th = skb_gro_header_fast(skb, off); | |
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 | thlen = th->doff * 4; | |
208 | if (thlen < sizeof(*th)) | |
209 | goto out; | |
210 | ||
211 | hlen = off + thlen; | |
212 | if (skb_gro_header_hard(skb, hlen)) { | |
213 | th = skb_gro_header_slow(skb, hlen, off); | |
214 | if (unlikely(!th)) | |
215 | goto out; | |
216 | } | |
217 | ||
218 | skb_gro_pull(skb, thlen); | |
219 | ||
220 | len = skb_gro_len(skb); | |
221 | flags = tcp_flag_word(th); | |
222 | ||
223 | for (; (p = *head); head = &p->next) { | |
224 | if (!NAPI_GRO_CB(p)->same_flow) | |
225 | continue; | |
226 | ||
227 | th2 = tcp_hdr(p); | |
228 | ||
229 | if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { | |
230 | NAPI_GRO_CB(p)->same_flow = 0; | |
231 | continue; | |
232 | } | |
233 | ||
234 | goto found; | |
235 | } | |
236 | ||
237 | goto out_check_final; | |
238 | ||
239 | found: | |
bf5a755f | 240 | /* Include the IP ID check below from the inner most IP hdr */ |
1530545e | 241 | flush = NAPI_GRO_CB(p)->flush; |
28850dc7 DB |
242 | flush |= (__force int)(flags & TCP_FLAG_CWR); |
243 | flush |= (__force int)((flags ^ tcp_flag_word(th2)) & | |
244 | ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); | |
245 | flush |= (__force int)(th->ack_seq ^ th2->ack_seq); | |
246 | for (i = sizeof(*th); i < thlen; i += 4) | |
247 | flush |= *(u32 *)((u8 *)th + i) ^ | |
248 | *(u32 *)((u8 *)th2 + i); | |
249 | ||
1530545e AD |
250 | /* When we receive our second frame we can made a decision on if we |
251 | * continue this flow as an atomic flow with a fixed ID or if we use | |
252 | * an incrementing ID. | |
253 | */ | |
254 | if (NAPI_GRO_CB(p)->flush_id != 1 || | |
255 | NAPI_GRO_CB(p)->count != 1 || | |
256 | !NAPI_GRO_CB(p)->is_atomic) | |
257 | flush |= NAPI_GRO_CB(p)->flush_id; | |
258 | else | |
259 | NAPI_GRO_CB(p)->is_atomic = false; | |
260 | ||
a7eea416 | 261 | mss = skb_shinfo(p)->gso_size; |
28850dc7 DB |
262 | |
263 | flush |= (len - 1) >= mss; | |
264 | flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); | |
265 | ||
266 | if (flush || skb_gro_receive(head, skb)) { | |
267 | mss = 1; | |
268 | goto out_check_final; | |
269 | } | |
270 | ||
271 | p = *head; | |
272 | th2 = tcp_hdr(p); | |
273 | tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); | |
274 | ||
275 | out_check_final: | |
276 | flush = len < mss; | |
277 | flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | | |
278 | TCP_FLAG_RST | TCP_FLAG_SYN | | |
279 | TCP_FLAG_FIN)); | |
280 | ||
281 | if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) | |
282 | pp = head; | |
283 | ||
284 | out: | |
bf5a755f | 285 | NAPI_GRO_CB(skb)->flush |= (flush != 0); |
28850dc7 DB |
286 | |
287 | return pp; | |
288 | } | |
28850dc7 DB |
289 | |
290 | int tcp_gro_complete(struct sk_buff *skb) | |
291 | { | |
292 | struct tcphdr *th = tcp_hdr(skb); | |
293 | ||
299603e8 | 294 | skb->csum_start = (unsigned char *)th - skb->head; |
28850dc7 DB |
295 | skb->csum_offset = offsetof(struct tcphdr, check); |
296 | skb->ip_summed = CHECKSUM_PARTIAL; | |
297 | ||
298 | skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; | |
299 | ||
300 | if (th->cwr) | |
301 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; | |
302 | ||
303 | return 0; | |
304 | } | |
305 | EXPORT_SYMBOL(tcp_gro_complete); | |
306 | ||
28850dc7 DB |
307 | static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) |
308 | { | |
cc5c00bb | 309 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
149d0774 TH |
310 | if (!NAPI_GRO_CB(skb)->flush && |
311 | skb_gro_checksum_validate(skb, IPPROTO_TCP, | |
312 | inet_gro_compute_pseudo)) { | |
28850dc7 DB |
313 | NAPI_GRO_CB(skb)->flush = 1; |
314 | return NULL; | |
28850dc7 DB |
315 | } |
316 | ||
317 | return tcp_gro_receive(head, skb); | |
318 | } | |
319 | ||
299603e8 | 320 | static int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
28850dc7 DB |
321 | { |
322 | const struct iphdr *iph = ip_hdr(skb); | |
323 | struct tcphdr *th = tcp_hdr(skb); | |
324 | ||
299603e8 JC |
325 | th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, |
326 | iph->daddr, 0); | |
c3caf119 | 327 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; |
28850dc7 | 328 | |
1530545e AD |
329 | if (NAPI_GRO_CB(skb)->is_atomic) |
330 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; | |
331 | ||
28850dc7 DB |
332 | return tcp_gro_complete(skb); |
333 | } | |
334 | ||
335 | static const struct net_offload tcpv4_offload = { | |
336 | .callbacks = { | |
d020f8f7 | 337 | .gso_segment = tcp4_gso_segment, |
28850dc7 DB |
338 | .gro_receive = tcp4_gro_receive, |
339 | .gro_complete = tcp4_gro_complete, | |
340 | }, | |
341 | }; | |
342 | ||
343 | int __init tcpv4_offload_init(void) | |
344 | { | |
345 | return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); | |
346 | } |