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 | ||
28be6e07 | 17 | struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
28850dc7 DB |
18 | netdev_features_t features) |
19 | { | |
20 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
0d08c42c | 21 | unsigned int sum_truesize = 0; |
28850dc7 DB |
22 | struct tcphdr *th; |
23 | unsigned int thlen; | |
24 | unsigned int seq; | |
25 | __be32 delta; | |
26 | unsigned int oldlen; | |
27 | unsigned int mss; | |
28 | struct sk_buff *gso_skb = skb; | |
29 | __sum16 newcheck; | |
30 | bool ooo_okay, copy_destructor; | |
31 | ||
32 | if (!pskb_may_pull(skb, sizeof(*th))) | |
33 | goto out; | |
34 | ||
35 | th = tcp_hdr(skb); | |
36 | thlen = th->doff * 4; | |
37 | if (thlen < sizeof(*th)) | |
38 | goto out; | |
39 | ||
40 | if (!pskb_may_pull(skb, thlen)) | |
41 | goto out; | |
42 | ||
43 | oldlen = (u16)~skb->len; | |
44 | __skb_pull(skb, thlen); | |
45 | ||
46 | mss = tcp_skb_mss(skb); | |
47 | if (unlikely(skb->len <= mss)) | |
48 | goto out; | |
49 | ||
50 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { | |
51 | /* Packet is from an untrusted source, reset gso_segs. */ | |
52 | int type = skb_shinfo(skb)->gso_type; | |
53 | ||
54 | if (unlikely(type & | |
55 | ~(SKB_GSO_TCPV4 | | |
56 | SKB_GSO_DODGY | | |
57 | SKB_GSO_TCP_ECN | | |
58 | SKB_GSO_TCPV6 | | |
59 | SKB_GSO_GRE | | |
cb32f511 | 60 | SKB_GSO_IPIP | |
61c1db7f | 61 | SKB_GSO_SIT | |
28850dc7 DB |
62 | SKB_GSO_MPLS | |
63 | SKB_GSO_UDP_TUNNEL | | |
64 | 0) || | |
65 | !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) | |
66 | goto out; | |
67 | ||
68 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
69 | ||
70 | segs = NULL; | |
71 | goto out; | |
72 | } | |
73 | ||
74 | copy_destructor = gso_skb->destructor == tcp_wfree; | |
75 | ooo_okay = gso_skb->ooo_okay; | |
76 | /* All segments but the first should have ooo_okay cleared */ | |
77 | skb->ooo_okay = 0; | |
78 | ||
79 | segs = skb_segment(skb, features); | |
80 | if (IS_ERR(segs)) | |
81 | goto out; | |
82 | ||
83 | /* Only first segment might have ooo_okay set */ | |
84 | segs->ooo_okay = ooo_okay; | |
85 | ||
86 | delta = htonl(oldlen + (thlen + mss)); | |
87 | ||
88 | skb = segs; | |
89 | th = tcp_hdr(skb); | |
90 | seq = ntohl(th->seq); | |
91 | ||
92 | newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + | |
93 | (__force u32)delta)); | |
94 | ||
95 | do { | |
96 | th->fin = th->psh = 0; | |
97 | th->check = newcheck; | |
98 | ||
99 | if (skb->ip_summed != CHECKSUM_PARTIAL) | |
100 | th->check = | |
101 | csum_fold(csum_partial(skb_transport_header(skb), | |
102 | thlen, skb->csum)); | |
103 | ||
104 | seq += mss; | |
105 | if (copy_destructor) { | |
106 | skb->destructor = gso_skb->destructor; | |
107 | skb->sk = gso_skb->sk; | |
0d08c42c | 108 | sum_truesize += skb->truesize; |
28850dc7 DB |
109 | } |
110 | skb = skb->next; | |
111 | th = tcp_hdr(skb); | |
112 | ||
113 | th->seq = htonl(seq); | |
114 | th->cwr = 0; | |
115 | } while (skb->next); | |
116 | ||
117 | /* Following permits TCP Small Queues to work well with GSO : | |
118 | * The callback to TCP stack will be called at the time last frag | |
119 | * is freed at TX completion, and not right now when gso_skb | |
120 | * is freed by GSO engine | |
121 | */ | |
122 | if (copy_destructor) { | |
123 | swap(gso_skb->sk, skb->sk); | |
124 | swap(gso_skb->destructor, skb->destructor); | |
0d08c42c ED |
125 | sum_truesize += skb->truesize; |
126 | atomic_add(sum_truesize - gso_skb->truesize, | |
127 | &skb->sk->sk_wmem_alloc); | |
28850dc7 DB |
128 | } |
129 | ||
130 | delta = htonl(oldlen + (skb_tail_pointer(skb) - | |
131 | skb_transport_header(skb)) + | |
132 | skb->data_len); | |
133 | th->check = ~csum_fold((__force __wsum)((__force u32)th->check + | |
134 | (__force u32)delta)); | |
135 | if (skb->ip_summed != CHECKSUM_PARTIAL) | |
136 | th->check = csum_fold(csum_partial(skb_transport_header(skb), | |
137 | thlen, skb->csum)); | |
138 | out: | |
139 | return segs; | |
140 | } | |
28be6e07 | 141 | EXPORT_SYMBOL(tcp_gso_segment); |
28850dc7 DB |
142 | |
143 | struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
144 | { | |
145 | struct sk_buff **pp = NULL; | |
146 | struct sk_buff *p; | |
147 | struct tcphdr *th; | |
148 | struct tcphdr *th2; | |
149 | unsigned int len; | |
150 | unsigned int thlen; | |
151 | __be32 flags; | |
152 | unsigned int mss = 1; | |
153 | unsigned int hlen; | |
154 | unsigned int off; | |
155 | int flush = 1; | |
156 | int i; | |
157 | ||
158 | off = skb_gro_offset(skb); | |
159 | hlen = off + sizeof(*th); | |
160 | th = skb_gro_header_fast(skb, off); | |
161 | if (skb_gro_header_hard(skb, hlen)) { | |
162 | th = skb_gro_header_slow(skb, hlen, off); | |
163 | if (unlikely(!th)) | |
164 | goto out; | |
165 | } | |
166 | ||
167 | thlen = th->doff * 4; | |
168 | if (thlen < sizeof(*th)) | |
169 | goto out; | |
170 | ||
171 | hlen = off + thlen; | |
172 | if (skb_gro_header_hard(skb, hlen)) { | |
173 | th = skb_gro_header_slow(skb, hlen, off); | |
174 | if (unlikely(!th)) | |
175 | goto out; | |
176 | } | |
177 | ||
178 | skb_gro_pull(skb, thlen); | |
179 | ||
180 | len = skb_gro_len(skb); | |
181 | flags = tcp_flag_word(th); | |
182 | ||
183 | for (; (p = *head); head = &p->next) { | |
184 | if (!NAPI_GRO_CB(p)->same_flow) | |
185 | continue; | |
186 | ||
187 | th2 = tcp_hdr(p); | |
188 | ||
189 | if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { | |
190 | NAPI_GRO_CB(p)->same_flow = 0; | |
191 | continue; | |
192 | } | |
193 | ||
194 | goto found; | |
195 | } | |
196 | ||
197 | goto out_check_final; | |
198 | ||
199 | found: | |
200 | flush = NAPI_GRO_CB(p)->flush; | |
201 | flush |= (__force int)(flags & TCP_FLAG_CWR); | |
202 | flush |= (__force int)((flags ^ tcp_flag_word(th2)) & | |
203 | ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); | |
204 | flush |= (__force int)(th->ack_seq ^ th2->ack_seq); | |
205 | for (i = sizeof(*th); i < thlen; i += 4) | |
206 | flush |= *(u32 *)((u8 *)th + i) ^ | |
207 | *(u32 *)((u8 *)th2 + i); | |
208 | ||
209 | mss = tcp_skb_mss(p); | |
210 | ||
211 | flush |= (len - 1) >= mss; | |
212 | flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); | |
213 | ||
214 | if (flush || skb_gro_receive(head, skb)) { | |
215 | mss = 1; | |
216 | goto out_check_final; | |
217 | } | |
218 | ||
219 | p = *head; | |
220 | th2 = tcp_hdr(p); | |
221 | tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); | |
222 | ||
223 | out_check_final: | |
224 | flush = len < mss; | |
225 | flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | | |
226 | TCP_FLAG_RST | TCP_FLAG_SYN | | |
227 | TCP_FLAG_FIN)); | |
228 | ||
229 | if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) | |
230 | pp = head; | |
231 | ||
232 | out: | |
233 | NAPI_GRO_CB(skb)->flush |= flush; | |
234 | ||
235 | return pp; | |
236 | } | |
237 | EXPORT_SYMBOL(tcp_gro_receive); | |
238 | ||
239 | int tcp_gro_complete(struct sk_buff *skb) | |
240 | { | |
241 | struct tcphdr *th = tcp_hdr(skb); | |
242 | ||
243 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
244 | skb->csum_offset = offsetof(struct tcphdr, check); | |
245 | skb->ip_summed = CHECKSUM_PARTIAL; | |
246 | ||
247 | skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; | |
248 | ||
249 | if (th->cwr) | |
250 | skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; | |
251 | ||
252 | return 0; | |
253 | } | |
254 | EXPORT_SYMBOL(tcp_gro_complete); | |
255 | ||
256 | static int tcp_v4_gso_send_check(struct sk_buff *skb) | |
257 | { | |
258 | const struct iphdr *iph; | |
259 | struct tcphdr *th; | |
260 | ||
261 | if (!pskb_may_pull(skb, sizeof(*th))) | |
262 | return -EINVAL; | |
263 | ||
264 | iph = ip_hdr(skb); | |
265 | th = tcp_hdr(skb); | |
266 | ||
267 | th->check = 0; | |
268 | skb->ip_summed = CHECKSUM_PARTIAL; | |
269 | __tcp_v4_send_check(skb, iph->saddr, iph->daddr); | |
270 | return 0; | |
271 | } | |
272 | ||
273 | static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
274 | { | |
275 | const struct iphdr *iph = skb_gro_network_header(skb); | |
276 | __wsum wsum; | |
28850dc7 | 277 | |
cc5c00bb HX |
278 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
279 | if (NAPI_GRO_CB(skb)->flush) | |
280 | goto skip_csum; | |
281 | ||
b8ee93ba HX |
282 | wsum = skb->csum; |
283 | ||
28850dc7 | 284 | switch (skb->ip_summed) { |
b8ee93ba HX |
285 | case CHECKSUM_NONE: |
286 | wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), | |
287 | 0); | |
288 | ||
289 | /* fall through */ | |
290 | ||
28850dc7 DB |
291 | case CHECKSUM_COMPLETE: |
292 | if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, | |
b8ee93ba | 293 | wsum)) { |
28850dc7 DB |
294 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
295 | break; | |
296 | } | |
b8ee93ba | 297 | |
28850dc7 DB |
298 | NAPI_GRO_CB(skb)->flush = 1; |
299 | return NULL; | |
28850dc7 DB |
300 | } |
301 | ||
cc5c00bb | 302 | skip_csum: |
28850dc7 DB |
303 | return tcp_gro_receive(head, skb); |
304 | } | |
305 | ||
306 | static int tcp4_gro_complete(struct sk_buff *skb) | |
307 | { | |
308 | const struct iphdr *iph = ip_hdr(skb); | |
309 | struct tcphdr *th = tcp_hdr(skb); | |
310 | ||
311 | th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb), | |
312 | iph->saddr, iph->daddr, 0); | |
313 | skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; | |
314 | ||
315 | return tcp_gro_complete(skb); | |
316 | } | |
317 | ||
318 | static const struct net_offload tcpv4_offload = { | |
319 | .callbacks = { | |
320 | .gso_send_check = tcp_v4_gso_send_check, | |
28be6e07 | 321 | .gso_segment = tcp_gso_segment, |
28850dc7 DB |
322 | .gro_receive = tcp4_gro_receive, |
323 | .gro_complete = tcp4_gro_complete, | |
324 | }, | |
325 | }; | |
326 | ||
327 | int __init tcpv4_offload_init(void) | |
328 | { | |
329 | return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); | |
330 | } |