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 | ||
28be6e07 | 32 | struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
28850dc7 DB |
33 | netdev_features_t features) |
34 | { | |
35 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
0d08c42c | 36 | unsigned int sum_truesize = 0; |
28850dc7 DB |
37 | struct tcphdr *th; |
38 | unsigned int thlen; | |
39 | unsigned int seq; | |
40 | __be32 delta; | |
41 | unsigned int oldlen; | |
42 | unsigned int mss; | |
43 | struct sk_buff *gso_skb = skb; | |
44 | __sum16 newcheck; | |
45 | bool ooo_okay, copy_destructor; | |
46 | ||
47 | if (!pskb_may_pull(skb, sizeof(*th))) | |
48 | goto out; | |
49 | ||
50 | th = tcp_hdr(skb); | |
51 | thlen = th->doff * 4; | |
52 | if (thlen < sizeof(*th)) | |
53 | goto out; | |
54 | ||
55 | if (!pskb_may_pull(skb, thlen)) | |
56 | goto out; | |
57 | ||
58 | oldlen = (u16)~skb->len; | |
59 | __skb_pull(skb, thlen); | |
60 | ||
61 | mss = tcp_skb_mss(skb); | |
62 | if (unlikely(skb->len <= mss)) | |
63 | goto out; | |
64 | ||
65 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { | |
66 | /* Packet is from an untrusted source, reset gso_segs. */ | |
67 | int type = skb_shinfo(skb)->gso_type; | |
68 | ||
69 | if (unlikely(type & | |
70 | ~(SKB_GSO_TCPV4 | | |
71 | SKB_GSO_DODGY | | |
72 | SKB_GSO_TCP_ECN | | |
73 | SKB_GSO_TCPV6 | | |
74 | SKB_GSO_GRE | | |
4749c09c | 75 | SKB_GSO_GRE_CSUM | |
cb32f511 | 76 | SKB_GSO_IPIP | |
61c1db7f | 77 | SKB_GSO_SIT | |
28850dc7 DB |
78 | SKB_GSO_MPLS | |
79 | SKB_GSO_UDP_TUNNEL | | |
0f4f4ffa | 80 | SKB_GSO_UDP_TUNNEL_CSUM | |
28850dc7 DB |
81 | 0) || |
82 | !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) | |
83 | goto out; | |
84 | ||
85 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
86 | ||
87 | segs = NULL; | |
88 | goto out; | |
89 | } | |
90 | ||
91 | copy_destructor = gso_skb->destructor == tcp_wfree; | |
92 | ooo_okay = gso_skb->ooo_okay; | |
93 | /* All segments but the first should have ooo_okay cleared */ | |
94 | skb->ooo_okay = 0; | |
95 | ||
96 | segs = skb_segment(skb, features); | |
97 | if (IS_ERR(segs)) | |
98 | goto out; | |
99 | ||
100 | /* Only first segment might have ooo_okay set */ | |
101 | segs->ooo_okay = ooo_okay; | |
102 | ||
103 | delta = htonl(oldlen + (thlen + mss)); | |
104 | ||
105 | skb = segs; | |
106 | th = tcp_hdr(skb); | |
107 | seq = ntohl(th->seq); | |
108 | ||
4ed2d765 WB |
109 | if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP)) |
110 | tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss); | |
111 | ||
28850dc7 DB |
112 | newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + |
113 | (__force u32)delta)); | |
114 | ||
115 | do { | |
116 | th->fin = th->psh = 0; | |
117 | th->check = newcheck; | |
118 | ||
119 | if (skb->ip_summed != CHECKSUM_PARTIAL) | |
e9c3a24b | 120 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
121 | |
122 | seq += mss; | |
123 | if (copy_destructor) { | |
124 | skb->destructor = gso_skb->destructor; | |
125 | skb->sk = gso_skb->sk; | |
0d08c42c | 126 | sum_truesize += skb->truesize; |
28850dc7 DB |
127 | } |
128 | skb = skb->next; | |
129 | th = tcp_hdr(skb); | |
130 | ||
131 | th->seq = htonl(seq); | |
132 | th->cwr = 0; | |
133 | } while (skb->next); | |
134 | ||
135 | /* Following permits TCP Small Queues to work well with GSO : | |
136 | * The callback to TCP stack will be called at the time last frag | |
137 | * is freed at TX completion, and not right now when gso_skb | |
138 | * is freed by GSO engine | |
139 | */ | |
140 | if (copy_destructor) { | |
141 | swap(gso_skb->sk, skb->sk); | |
142 | swap(gso_skb->destructor, skb->destructor); | |
0d08c42c ED |
143 | sum_truesize += skb->truesize; |
144 | atomic_add(sum_truesize - gso_skb->truesize, | |
145 | &skb->sk->sk_wmem_alloc); | |
28850dc7 DB |
146 | } |
147 | ||
148 | delta = htonl(oldlen + (skb_tail_pointer(skb) - | |
149 | skb_transport_header(skb)) + | |
150 | skb->data_len); | |
151 | th->check = ~csum_fold((__force __wsum)((__force u32)th->check + | |
152 | (__force u32)delta)); | |
153 | if (skb->ip_summed != CHECKSUM_PARTIAL) | |
e9c3a24b | 154 | th->check = gso_make_checksum(skb, ~th->check); |
28850dc7 DB |
155 | out: |
156 | return segs; | |
157 | } | |
28850dc7 DB |
158 | |
159 | struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
160 | { | |
161 | struct sk_buff **pp = NULL; | |
162 | struct sk_buff *p; | |
163 | struct tcphdr *th; | |
164 | struct tcphdr *th2; | |
165 | unsigned int len; | |
166 | unsigned int thlen; | |
167 | __be32 flags; | |
168 | unsigned int mss = 1; | |
169 | unsigned int hlen; | |
170 | unsigned int off; | |
171 | int flush = 1; | |
172 | int i; | |
173 | ||
174 | off = skb_gro_offset(skb); | |
175 | hlen = off + sizeof(*th); | |
176 | th = skb_gro_header_fast(skb, off); | |
177 | if (skb_gro_header_hard(skb, hlen)) { | |
178 | th = skb_gro_header_slow(skb, hlen, off); | |
179 | if (unlikely(!th)) | |
180 | goto out; | |
181 | } | |
182 | ||
183 | thlen = th->doff * 4; | |
184 | if (thlen < sizeof(*th)) | |
185 | goto out; | |
186 | ||
187 | hlen = off + thlen; | |
188 | if (skb_gro_header_hard(skb, hlen)) { | |
189 | th = skb_gro_header_slow(skb, hlen, off); | |
190 | if (unlikely(!th)) | |
191 | goto out; | |
192 | } | |
193 | ||
194 | skb_gro_pull(skb, thlen); | |
195 | ||
196 | len = skb_gro_len(skb); | |
197 | flags = tcp_flag_word(th); | |
198 | ||
199 | for (; (p = *head); head = &p->next) { | |
200 | if (!NAPI_GRO_CB(p)->same_flow) | |
201 | continue; | |
202 | ||
203 | th2 = tcp_hdr(p); | |
204 | ||
205 | if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { | |
206 | NAPI_GRO_CB(p)->same_flow = 0; | |
207 | continue; | |
208 | } | |
209 | ||
210 | goto found; | |
211 | } | |
212 | ||
213 | goto out_check_final; | |
214 | ||
215 | found: | |
bf5a755f JC |
216 | /* Include the IP ID check below from the inner most IP hdr */ |
217 | flush = NAPI_GRO_CB(p)->flush | NAPI_GRO_CB(p)->flush_id; | |
28850dc7 DB |
218 | flush |= (__force int)(flags & TCP_FLAG_CWR); |
219 | flush |= (__force int)((flags ^ tcp_flag_word(th2)) & | |
220 | ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); | |
221 | flush |= (__force int)(th->ack_seq ^ th2->ack_seq); | |
222 | for (i = sizeof(*th); i < thlen; i += 4) | |
223 | flush |= *(u32 *)((u8 *)th + i) ^ | |
224 | *(u32 *)((u8 *)th2 + i); | |
225 | ||
226 | mss = tcp_skb_mss(p); | |
227 | ||
228 | flush |= (len - 1) >= mss; | |
229 | flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); | |
230 | ||
231 | if (flush || skb_gro_receive(head, skb)) { | |
232 | mss = 1; | |
233 | goto out_check_final; | |
234 | } | |
235 | ||
236 | p = *head; | |
237 | th2 = tcp_hdr(p); | |
238 | tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); | |
239 | ||
240 | out_check_final: | |
241 | flush = len < mss; | |
242 | flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | | |
243 | TCP_FLAG_RST | TCP_FLAG_SYN | | |
244 | TCP_FLAG_FIN)); | |
245 | ||
246 | if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) | |
247 | pp = head; | |
248 | ||
249 | out: | |
bf5a755f | 250 | NAPI_GRO_CB(skb)->flush |= (flush != 0); |
28850dc7 DB |
251 | |
252 | return pp; | |
253 | } | |
28850dc7 DB |
254 | |
255 | int tcp_gro_complete(struct sk_buff *skb) | |
256 | { | |
257 | struct tcphdr *th = tcp_hdr(skb); | |
258 | ||
299603e8 | 259 | skb->csum_start = (unsigned char *)th - skb->head; |
28850dc7 DB |
260 | skb->csum_offset = offsetof(struct tcphdr, check); |
261 | skb->ip_summed = CHECKSUM_PARTIAL; | |
262 | ||
263 | skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; | |
264 | ||
265 | if (th->cwr) | |
266 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; | |
267 | ||
268 | return 0; | |
269 | } | |
270 | EXPORT_SYMBOL(tcp_gro_complete); | |
271 | ||
272 | static int tcp_v4_gso_send_check(struct sk_buff *skb) | |
273 | { | |
274 | const struct iphdr *iph; | |
275 | struct tcphdr *th; | |
276 | ||
277 | if (!pskb_may_pull(skb, sizeof(*th))) | |
278 | return -EINVAL; | |
279 | ||
280 | iph = ip_hdr(skb); | |
281 | th = tcp_hdr(skb); | |
282 | ||
283 | th->check = 0; | |
284 | skb->ip_summed = CHECKSUM_PARTIAL; | |
285 | __tcp_v4_send_check(skb, iph->saddr, iph->daddr); | |
286 | return 0; | |
287 | } | |
288 | ||
289 | static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
290 | { | |
299603e8 | 291 | /* Use the IP hdr immediately proceeding for this transport */ |
28850dc7 DB |
292 | const struct iphdr *iph = skb_gro_network_header(skb); |
293 | __wsum wsum; | |
28850dc7 | 294 | |
cc5c00bb HX |
295 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
296 | if (NAPI_GRO_CB(skb)->flush) | |
297 | goto skip_csum; | |
298 | ||
bf5a755f | 299 | wsum = NAPI_GRO_CB(skb)->csum; |
b8ee93ba | 300 | |
28850dc7 | 301 | switch (skb->ip_summed) { |
b8ee93ba HX |
302 | case CHECKSUM_NONE: |
303 | wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), | |
304 | 0); | |
305 | ||
306 | /* fall through */ | |
307 | ||
28850dc7 DB |
308 | case CHECKSUM_COMPLETE: |
309 | if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, | |
b8ee93ba | 310 | wsum)) { |
28850dc7 DB |
311 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
312 | break; | |
313 | } | |
b8ee93ba | 314 | |
28850dc7 DB |
315 | NAPI_GRO_CB(skb)->flush = 1; |
316 | return NULL; | |
28850dc7 DB |
317 | } |
318 | ||
cc5c00bb | 319 | skip_csum: |
28850dc7 DB |
320 | return tcp_gro_receive(head, skb); |
321 | } | |
322 | ||
299603e8 | 323 | static int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
28850dc7 DB |
324 | { |
325 | const struct iphdr *iph = ip_hdr(skb); | |
326 | struct tcphdr *th = tcp_hdr(skb); | |
327 | ||
299603e8 JC |
328 | th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, |
329 | iph->daddr, 0); | |
c3caf119 | 330 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; |
28850dc7 DB |
331 | |
332 | return tcp_gro_complete(skb); | |
333 | } | |
334 | ||
335 | static const struct net_offload tcpv4_offload = { | |
336 | .callbacks = { | |
337 | .gso_send_check = tcp_v4_gso_send_check, | |
28be6e07 | 338 | .gso_segment = tcp_gso_segment, |
28850dc7 DB |
339 | .gro_receive = tcp4_gro_receive, |
340 | .gro_complete = tcp4_gro_complete, | |
341 | }, | |
342 | }; | |
343 | ||
344 | int __init tcpv4_offload_init(void) | |
345 | { | |
346 | return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); | |
347 | } |