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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 TH |
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 | ||
28be6e07 | 54 | struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
28850dc7 DB |
55 | netdev_features_t features) |
56 | { | |
57 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
0d08c42c | 58 | unsigned int sum_truesize = 0; |
28850dc7 DB |
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 | ||
28850dc7 DB |
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 | ||
a7eea416 | 80 | mss = skb_shinfo(skb)->gso_size; |
28850dc7 DB |
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. */ | |
28850dc7 DB |
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 | ||
07b26c94 SK |
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 | ||
28850dc7 DB |
112 | delta = htonl(oldlen + (thlen + mss)); |
113 | ||
114 | skb = segs; | |
115 | th = tcp_hdr(skb); | |
116 | seq = ntohl(th->seq); | |
117 | ||
4ed2d765 WB |
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 | ||
28850dc7 DB |
121 | newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + |
122 | (__force u32)delta)); | |
123 | ||
802ab55a | 124 | while (skb->next) { |
28850dc7 DB |
125 | th->fin = th->psh = 0; |
126 | th->check = newcheck; | |
127 | ||
08b64fcc AD |
128 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
129 | gso_reset_checksum(skb, ~th->check); | |
130 | else | |
e9c3a24b | 131 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
132 | |
133 | seq += mss; | |
134 | if (copy_destructor) { | |
135 | skb->destructor = gso_skb->destructor; | |
136 | skb->sk = gso_skb->sk; | |
0d08c42c | 137 | sum_truesize += skb->truesize; |
28850dc7 DB |
138 | } |
139 | skb = skb->next; | |
140 | th = tcp_hdr(skb); | |
141 | ||
142 | th->seq = htonl(seq); | |
143 | th->cwr = 0; | |
802ab55a | 144 | } |
28850dc7 DB |
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); | |
0d08c42c | 154 | sum_truesize += skb->truesize; |
14afee4b | 155 | refcount_add(sum_truesize - gso_skb->truesize, |
0d08c42c | 156 | &skb->sk->sk_wmem_alloc); |
28850dc7 DB |
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)); | |
08b64fcc AD |
164 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
165 | gso_reset_checksum(skb, ~th->check); | |
166 | else | |
e9c3a24b | 167 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
168 | out: |
169 | return segs; | |
170 | } | |
28850dc7 DB |
171 | |
172 | struct 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 | ||
228 | found: | |
bf5a755f | 229 | /* Include the IP ID check below from the inner most IP hdr */ |
1530545e | 230 | flush = NAPI_GRO_CB(p)->flush; |
28850dc7 DB |
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 | ||
1530545e AD |
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 | ||
a7eea416 | 250 | mss = skb_shinfo(p)->gso_size; |
28850dc7 DB |
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 | ||
264 | out_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 | ||
273 | out: | |
bf5a755f | 274 | NAPI_GRO_CB(skb)->flush |= (flush != 0); |
28850dc7 DB |
275 | |
276 | return pp; | |
277 | } | |
28850dc7 DB |
278 | |
279 | int tcp_gro_complete(struct sk_buff *skb) | |
280 | { | |
281 | struct tcphdr *th = tcp_hdr(skb); | |
282 | ||
299603e8 | 283 | skb->csum_start = (unsigned char *)th - skb->head; |
28850dc7 DB |
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 | } | |
294 | EXPORT_SYMBOL(tcp_gro_complete); | |
295 | ||
28850dc7 DB |
296 | static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) |
297 | { | |
cc5c00bb | 298 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
149d0774 TH |
299 | if (!NAPI_GRO_CB(skb)->flush && |
300 | skb_gro_checksum_validate(skb, IPPROTO_TCP, | |
301 | inet_gro_compute_pseudo)) { | |
28850dc7 DB |
302 | NAPI_GRO_CB(skb)->flush = 1; |
303 | return NULL; | |
28850dc7 DB |
304 | } |
305 | ||
306 | return tcp_gro_receive(head, skb); | |
307 | } | |
308 | ||
299603e8 | 309 | static int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
28850dc7 DB |
310 | { |
311 | const struct iphdr *iph = ip_hdr(skb); | |
312 | struct tcphdr *th = tcp_hdr(skb); | |
313 | ||
299603e8 JC |
314 | th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, |
315 | iph->daddr, 0); | |
c3caf119 | 316 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; |
28850dc7 | 317 | |
1530545e AD |
318 | if (NAPI_GRO_CB(skb)->is_atomic) |
319 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; | |
320 | ||
28850dc7 DB |
321 | return tcp_gro_complete(skb); |
322 | } | |
323 | ||
324 | static const struct net_offload tcpv4_offload = { | |
325 | .callbacks = { | |
d020f8f7 | 326 | .gso_segment = tcp4_gso_segment, |
28850dc7 DB |
327 | .gro_receive = tcp4_gro_receive, |
328 | .gro_complete = tcp4_gro_complete, | |
329 | }, | |
330 | }; | |
331 | ||
332 | int __init tcpv4_offload_init(void) | |
333 | { | |
334 | return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); | |
335 | } |