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. */ | |
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 | | |
cbc53e08 | 92 | SKB_GSO_TCP_FIXEDID | |
28850dc7 DB |
93 | SKB_GSO_TCPV6 | |
94 | SKB_GSO_GRE | | |
4749c09c | 95 | SKB_GSO_GRE_CSUM | |
cb32f511 | 96 | SKB_GSO_IPIP | |
61c1db7f | 97 | SKB_GSO_SIT | |
28850dc7 | 98 | SKB_GSO_UDP_TUNNEL | |
0f4f4ffa | 99 | SKB_GSO_UDP_TUNNEL_CSUM | |
e585f236 | 100 | SKB_GSO_TUNNEL_REMCSUM | |
28850dc7 | 101 | 0) || |
cbc53e08 AD |
102 | !(type & (SKB_GSO_TCPV4 | |
103 | SKB_GSO_TCPV6)))) | |
28850dc7 DB |
104 | goto out; |
105 | ||
106 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
107 | ||
108 | segs = NULL; | |
109 | goto out; | |
110 | } | |
111 | ||
802ab55a AD |
112 | /* GSO partial only requires splitting the frame into an MSS |
113 | * multiple and possibly a remainder. So update the mss now. | |
114 | */ | |
115 | if (features & NETIF_F_GSO_PARTIAL) | |
116 | mss = skb->len - (skb->len % mss); | |
117 | ||
28850dc7 DB |
118 | copy_destructor = gso_skb->destructor == tcp_wfree; |
119 | ooo_okay = gso_skb->ooo_okay; | |
120 | /* All segments but the first should have ooo_okay cleared */ | |
121 | skb->ooo_okay = 0; | |
122 | ||
123 | segs = skb_segment(skb, features); | |
124 | if (IS_ERR(segs)) | |
125 | goto out; | |
126 | ||
127 | /* Only first segment might have ooo_okay set */ | |
128 | segs->ooo_okay = ooo_okay; | |
129 | ||
130 | delta = htonl(oldlen + (thlen + mss)); | |
131 | ||
132 | skb = segs; | |
133 | th = tcp_hdr(skb); | |
134 | seq = ntohl(th->seq); | |
135 | ||
4ed2d765 WB |
136 | if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP)) |
137 | tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss); | |
138 | ||
28850dc7 DB |
139 | newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + |
140 | (__force u32)delta)); | |
141 | ||
802ab55a | 142 | while (skb->next) { |
28850dc7 DB |
143 | th->fin = th->psh = 0; |
144 | th->check = newcheck; | |
145 | ||
08b64fcc AD |
146 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
147 | gso_reset_checksum(skb, ~th->check); | |
148 | else | |
e9c3a24b | 149 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
150 | |
151 | seq += mss; | |
152 | if (copy_destructor) { | |
153 | skb->destructor = gso_skb->destructor; | |
154 | skb->sk = gso_skb->sk; | |
0d08c42c | 155 | sum_truesize += skb->truesize; |
28850dc7 DB |
156 | } |
157 | skb = skb->next; | |
158 | th = tcp_hdr(skb); | |
159 | ||
160 | th->seq = htonl(seq); | |
161 | th->cwr = 0; | |
802ab55a | 162 | } |
28850dc7 DB |
163 | |
164 | /* Following permits TCP Small Queues to work well with GSO : | |
165 | * The callback to TCP stack will be called at the time last frag | |
166 | * is freed at TX completion, and not right now when gso_skb | |
167 | * is freed by GSO engine | |
168 | */ | |
169 | if (copy_destructor) { | |
170 | swap(gso_skb->sk, skb->sk); | |
171 | swap(gso_skb->destructor, skb->destructor); | |
0d08c42c ED |
172 | sum_truesize += skb->truesize; |
173 | atomic_add(sum_truesize - gso_skb->truesize, | |
174 | &skb->sk->sk_wmem_alloc); | |
28850dc7 DB |
175 | } |
176 | ||
177 | delta = htonl(oldlen + (skb_tail_pointer(skb) - | |
178 | skb_transport_header(skb)) + | |
179 | skb->data_len); | |
180 | th->check = ~csum_fold((__force __wsum)((__force u32)th->check + | |
181 | (__force u32)delta)); | |
08b64fcc AD |
182 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
183 | gso_reset_checksum(skb, ~th->check); | |
184 | else | |
e9c3a24b | 185 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
186 | out: |
187 | return segs; | |
188 | } | |
28850dc7 DB |
189 | |
190 | struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
191 | { | |
192 | struct sk_buff **pp = NULL; | |
193 | struct sk_buff *p; | |
194 | struct tcphdr *th; | |
195 | struct tcphdr *th2; | |
196 | unsigned int len; | |
197 | unsigned int thlen; | |
198 | __be32 flags; | |
199 | unsigned int mss = 1; | |
200 | unsigned int hlen; | |
201 | unsigned int off; | |
202 | int flush = 1; | |
203 | int i; | |
204 | ||
205 | off = skb_gro_offset(skb); | |
206 | hlen = off + sizeof(*th); | |
207 | th = skb_gro_header_fast(skb, off); | |
208 | if (skb_gro_header_hard(skb, hlen)) { | |
209 | th = skb_gro_header_slow(skb, hlen, off); | |
210 | if (unlikely(!th)) | |
211 | goto out; | |
212 | } | |
213 | ||
214 | thlen = th->doff * 4; | |
215 | if (thlen < sizeof(*th)) | |
216 | goto out; | |
217 | ||
218 | hlen = off + thlen; | |
219 | if (skb_gro_header_hard(skb, hlen)) { | |
220 | th = skb_gro_header_slow(skb, hlen, off); | |
221 | if (unlikely(!th)) | |
222 | goto out; | |
223 | } | |
224 | ||
225 | skb_gro_pull(skb, thlen); | |
226 | ||
227 | len = skb_gro_len(skb); | |
228 | flags = tcp_flag_word(th); | |
229 | ||
230 | for (; (p = *head); head = &p->next) { | |
231 | if (!NAPI_GRO_CB(p)->same_flow) | |
232 | continue; | |
233 | ||
234 | th2 = tcp_hdr(p); | |
235 | ||
236 | if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { | |
237 | NAPI_GRO_CB(p)->same_flow = 0; | |
238 | continue; | |
239 | } | |
240 | ||
241 | goto found; | |
242 | } | |
243 | ||
244 | goto out_check_final; | |
245 | ||
246 | found: | |
bf5a755f | 247 | /* Include the IP ID check below from the inner most IP hdr */ |
1530545e | 248 | flush = NAPI_GRO_CB(p)->flush; |
28850dc7 DB |
249 | flush |= (__force int)(flags & TCP_FLAG_CWR); |
250 | flush |= (__force int)((flags ^ tcp_flag_word(th2)) & | |
251 | ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); | |
252 | flush |= (__force int)(th->ack_seq ^ th2->ack_seq); | |
253 | for (i = sizeof(*th); i < thlen; i += 4) | |
254 | flush |= *(u32 *)((u8 *)th + i) ^ | |
255 | *(u32 *)((u8 *)th2 + i); | |
256 | ||
1530545e AD |
257 | /* When we receive our second frame we can made a decision on if we |
258 | * continue this flow as an atomic flow with a fixed ID or if we use | |
259 | * an incrementing ID. | |
260 | */ | |
261 | if (NAPI_GRO_CB(p)->flush_id != 1 || | |
262 | NAPI_GRO_CB(p)->count != 1 || | |
263 | !NAPI_GRO_CB(p)->is_atomic) | |
264 | flush |= NAPI_GRO_CB(p)->flush_id; | |
265 | else | |
266 | NAPI_GRO_CB(p)->is_atomic = false; | |
267 | ||
a7eea416 | 268 | mss = skb_shinfo(p)->gso_size; |
28850dc7 DB |
269 | |
270 | flush |= (len - 1) >= mss; | |
271 | flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); | |
272 | ||
273 | if (flush || skb_gro_receive(head, skb)) { | |
274 | mss = 1; | |
275 | goto out_check_final; | |
276 | } | |
277 | ||
278 | p = *head; | |
279 | th2 = tcp_hdr(p); | |
280 | tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); | |
281 | ||
282 | out_check_final: | |
283 | flush = len < mss; | |
284 | flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | | |
285 | TCP_FLAG_RST | TCP_FLAG_SYN | | |
286 | TCP_FLAG_FIN)); | |
287 | ||
288 | if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) | |
289 | pp = head; | |
290 | ||
291 | out: | |
bf5a755f | 292 | NAPI_GRO_CB(skb)->flush |= (flush != 0); |
28850dc7 DB |
293 | |
294 | return pp; | |
295 | } | |
28850dc7 DB |
296 | |
297 | int tcp_gro_complete(struct sk_buff *skb) | |
298 | { | |
299 | struct tcphdr *th = tcp_hdr(skb); | |
300 | ||
299603e8 | 301 | skb->csum_start = (unsigned char *)th - skb->head; |
28850dc7 DB |
302 | skb->csum_offset = offsetof(struct tcphdr, check); |
303 | skb->ip_summed = CHECKSUM_PARTIAL; | |
304 | ||
305 | skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; | |
306 | ||
307 | if (th->cwr) | |
308 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; | |
309 | ||
310 | return 0; | |
311 | } | |
312 | EXPORT_SYMBOL(tcp_gro_complete); | |
313 | ||
28850dc7 DB |
314 | static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) |
315 | { | |
cc5c00bb | 316 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
149d0774 TH |
317 | if (!NAPI_GRO_CB(skb)->flush && |
318 | skb_gro_checksum_validate(skb, IPPROTO_TCP, | |
319 | inet_gro_compute_pseudo)) { | |
28850dc7 DB |
320 | NAPI_GRO_CB(skb)->flush = 1; |
321 | return NULL; | |
28850dc7 DB |
322 | } |
323 | ||
324 | return tcp_gro_receive(head, skb); | |
325 | } | |
326 | ||
299603e8 | 327 | static int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
28850dc7 DB |
328 | { |
329 | const struct iphdr *iph = ip_hdr(skb); | |
330 | struct tcphdr *th = tcp_hdr(skb); | |
331 | ||
299603e8 JC |
332 | th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, |
333 | iph->daddr, 0); | |
c3caf119 | 334 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; |
28850dc7 | 335 | |
1530545e AD |
336 | if (NAPI_GRO_CB(skb)->is_atomic) |
337 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; | |
338 | ||
28850dc7 DB |
339 | return tcp_gro_complete(skb); |
340 | } | |
341 | ||
342 | static const struct net_offload tcpv4_offload = { | |
343 | .callbacks = { | |
d020f8f7 | 344 | .gso_segment = tcp4_gso_segment, |
28850dc7 DB |
345 | .gro_receive = tcp4_gro_receive, |
346 | .gro_complete = tcp4_gro_complete, | |
347 | }, | |
348 | }; | |
349 | ||
350 | int __init tcpv4_offload_init(void) | |
351 | { | |
352 | return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); | |
353 | } |