blob: 5c5964962d0ca2f00157c4e533597a34b9a96979 [file] [log] [blame]
Daniel Borkmann28850dc2013-06-07 05:11:46 +00001/*
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
Willem de Bruijnf066e2b2014-08-06 15:09:44 -040017static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
18 unsigned int seq, unsigned int mss)
Willem de Bruijn4ed2d762014-08-04 22:11:49 -040019{
20 while (skb) {
Willem de Bruijnf066e2b2014-08-06 15:09:44 -040021 if (before(ts_seq, seq + mss)) {
22 skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP;
Willem de Bruijn4ed2d762014-08-04 22:11:49 -040023 skb_shinfo(skb)->tskey = ts_seq;
24 return;
25 }
26
27 skb = skb->next;
28 seq += mss;
29 }
30}
31
Eric Dumazet74abc202015-02-26 19:08:59 -080032static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
33 netdev_features_t features)
Tom Herbertd020f8f2014-09-20 14:52:28 -070034{
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
Eric Dumazet28be6e02013-10-18 10:36:17 -070054struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
Daniel Borkmann28850dc2013-06-07 05:11:46 +000055 netdev_features_t features)
56{
57 struct sk_buff *segs = ERR_PTR(-EINVAL);
Eric Dumazet0d08c422013-10-25 17:26:17 -070058 unsigned int sum_truesize = 0;
Daniel Borkmann28850dc2013-06-07 05:11:46 +000059 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
Daniel Borkmann28850dc2013-06-07 05:11:46 +000069 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
Eric Dumazeta7eea412015-06-11 09:15:15 -070080 mss = skb_shinfo(skb)->gso_size;
Daniel Borkmann28850dc2013-06-07 05:11:46 +000081 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. */
Daniel Borkmann28850dc2013-06-07 05:11:46 +000086
87 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
88
89 segs = NULL;
90 goto out;
91 }
92
Alexander Duyck802ab552016-04-10 21:45:03 -040093 /* GSO partial only requires splitting the frame into an MSS
94 * multiple and possibly a remainder. So update the mss now.
95 */
96 if (features & NETIF_F_GSO_PARTIAL)
97 mss = skb->len - (skb->len % mss);
98
Daniel Borkmann28850dc2013-06-07 05:11:46 +000099 copy_destructor = gso_skb->destructor == tcp_wfree;
100 ooo_okay = gso_skb->ooo_okay;
101 /* All segments but the first should have ooo_okay cleared */
102 skb->ooo_okay = 0;
103
104 segs = skb_segment(skb, features);
105 if (IS_ERR(segs))
106 goto out;
107
108 /* Only first segment might have ooo_okay set */
109 segs->ooo_okay = ooo_okay;
110
111 delta = htonl(oldlen + (thlen + mss));
112
113 skb = segs;
114 th = tcp_hdr(skb);
115 seq = ntohl(th->seq);
116
Willem de Bruijn4ed2d762014-08-04 22:11:49 -0400117 if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
118 tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
119
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000120 newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
121 (__force u32)delta));
122
Alexander Duyck802ab552016-04-10 21:45:03 -0400123 while (skb->next) {
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000124 th->fin = th->psh = 0;
125 th->check = newcheck;
126
Alexander Duyck08b64fc2016-02-05 15:27:49 -0800127 if (skb->ip_summed == CHECKSUM_PARTIAL)
128 gso_reset_checksum(skb, ~th->check);
129 else
Tom Herberte9c3a242014-06-04 17:20:09 -0700130 th->check = gso_make_checksum(skb, ~th->check);
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000131
132 seq += mss;
133 if (copy_destructor) {
134 skb->destructor = gso_skb->destructor;
135 skb->sk = gso_skb->sk;
Eric Dumazet0d08c422013-10-25 17:26:17 -0700136 sum_truesize += skb->truesize;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000137 }
138 skb = skb->next;
139 th = tcp_hdr(skb);
140
141 th->seq = htonl(seq);
142 th->cwr = 0;
Alexander Duyck802ab552016-04-10 21:45:03 -0400143 }
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000144
145 /* Following permits TCP Small Queues to work well with GSO :
146 * The callback to TCP stack will be called at the time last frag
147 * is freed at TX completion, and not right now when gso_skb
148 * is freed by GSO engine
149 */
150 if (copy_destructor) {
151 swap(gso_skb->sk, skb->sk);
152 swap(gso_skb->destructor, skb->destructor);
Eric Dumazet0d08c422013-10-25 17:26:17 -0700153 sum_truesize += skb->truesize;
154 atomic_add(sum_truesize - gso_skb->truesize,
155 &skb->sk->sk_wmem_alloc);
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000156 }
157
158 delta = htonl(oldlen + (skb_tail_pointer(skb) -
159 skb_transport_header(skb)) +
160 skb->data_len);
161 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
162 (__force u32)delta));
Alexander Duyck08b64fc2016-02-05 15:27:49 -0800163 if (skb->ip_summed == CHECKSUM_PARTIAL)
164 gso_reset_checksum(skb, ~th->check);
165 else
Tom Herberte9c3a242014-06-04 17:20:09 -0700166 th->check = gso_make_checksum(skb, ~th->check);
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000167out:
168 return segs;
169}
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000170
171struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
172{
173 struct sk_buff **pp = NULL;
174 struct sk_buff *p;
175 struct tcphdr *th;
176 struct tcphdr *th2;
177 unsigned int len;
178 unsigned int thlen;
179 __be32 flags;
180 unsigned int mss = 1;
181 unsigned int hlen;
182 unsigned int off;
183 int flush = 1;
184 int i;
185
186 off = skb_gro_offset(skb);
187 hlen = off + sizeof(*th);
188 th = skb_gro_header_fast(skb, off);
189 if (skb_gro_header_hard(skb, hlen)) {
190 th = skb_gro_header_slow(skb, hlen, off);
191 if (unlikely(!th))
192 goto out;
193 }
194
195 thlen = th->doff * 4;
196 if (thlen < sizeof(*th))
197 goto out;
198
199 hlen = off + thlen;
200 if (skb_gro_header_hard(skb, hlen)) {
201 th = skb_gro_header_slow(skb, hlen, off);
202 if (unlikely(!th))
203 goto out;
204 }
205
206 skb_gro_pull(skb, thlen);
207
208 len = skb_gro_len(skb);
209 flags = tcp_flag_word(th);
210
211 for (; (p = *head); head = &p->next) {
212 if (!NAPI_GRO_CB(p)->same_flow)
213 continue;
214
215 th2 = tcp_hdr(p);
216
217 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
218 NAPI_GRO_CB(p)->same_flow = 0;
219 continue;
220 }
221
222 goto found;
223 }
224
225 goto out_check_final;
226
227found:
Jerry Chubf5a7552014-01-07 10:23:19 -0800228 /* Include the IP ID check below from the inner most IP hdr */
Alexander Duyck15305452016-04-10 21:44:57 -0400229 flush = NAPI_GRO_CB(p)->flush;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000230 flush |= (__force int)(flags & TCP_FLAG_CWR);
231 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
232 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
233 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
234 for (i = sizeof(*th); i < thlen; i += 4)
235 flush |= *(u32 *)((u8 *)th + i) ^
236 *(u32 *)((u8 *)th2 + i);
237
Alexander Duyck15305452016-04-10 21:44:57 -0400238 /* When we receive our second frame we can made a decision on if we
239 * continue this flow as an atomic flow with a fixed ID or if we use
240 * an incrementing ID.
241 */
242 if (NAPI_GRO_CB(p)->flush_id != 1 ||
243 NAPI_GRO_CB(p)->count != 1 ||
244 !NAPI_GRO_CB(p)->is_atomic)
245 flush |= NAPI_GRO_CB(p)->flush_id;
246 else
247 NAPI_GRO_CB(p)->is_atomic = false;
248
Eric Dumazeta7eea412015-06-11 09:15:15 -0700249 mss = skb_shinfo(p)->gso_size;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000250
251 flush |= (len - 1) >= mss;
252 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
253
254 if (flush || skb_gro_receive(head, skb)) {
255 mss = 1;
256 goto out_check_final;
257 }
258
259 p = *head;
260 th2 = tcp_hdr(p);
261 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
262
263out_check_final:
264 flush = len < mss;
265 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
266 TCP_FLAG_RST | TCP_FLAG_SYN |
267 TCP_FLAG_FIN));
268
269 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
270 pp = head;
271
272out:
Jerry Chubf5a7552014-01-07 10:23:19 -0800273 NAPI_GRO_CB(skb)->flush |= (flush != 0);
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000274
275 return pp;
276}
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000277
278int tcp_gro_complete(struct sk_buff *skb)
279{
280 struct tcphdr *th = tcp_hdr(skb);
281
Jerry Chu299603e82013-12-11 20:53:45 -0800282 skb->csum_start = (unsigned char *)th - skb->head;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000283 skb->csum_offset = offsetof(struct tcphdr, check);
284 skb->ip_summed = CHECKSUM_PARTIAL;
285
286 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
287
288 if (th->cwr)
289 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
290
291 return 0;
292}
293EXPORT_SYMBOL(tcp_gro_complete);
294
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000295static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
296{
Herbert Xucc5c00b2013-11-22 10:31:29 +0800297 /* Don't bother verifying checksum if we're going to flush anyway. */
Tom Herbert149d0772014-08-22 13:34:30 -0700298 if (!NAPI_GRO_CB(skb)->flush &&
299 skb_gro_checksum_validate(skb, IPPROTO_TCP,
300 inet_gro_compute_pseudo)) {
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000301 NAPI_GRO_CB(skb)->flush = 1;
302 return NULL;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000303 }
304
305 return tcp_gro_receive(head, skb);
306}
307
Jerry Chu299603e82013-12-11 20:53:45 -0800308static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000309{
310 const struct iphdr *iph = ip_hdr(skb);
311 struct tcphdr *th = tcp_hdr(skb);
312
Jerry Chu299603e82013-12-11 20:53:45 -0800313 th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
314 iph->daddr, 0);
Jerry Chuc3caf112014-07-14 15:54:46 -0700315 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000316
Alexander Duyck15305452016-04-10 21:44:57 -0400317 if (NAPI_GRO_CB(skb)->is_atomic)
318 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;
319
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000320 return tcp_gro_complete(skb);
321}
322
323static const struct net_offload tcpv4_offload = {
324 .callbacks = {
Tom Herbertd020f8f2014-09-20 14:52:28 -0700325 .gso_segment = tcp4_gso_segment,
Daniel Borkmann28850dc2013-06-07 05:11:46 +0000326 .gro_receive = tcp4_gro_receive,
327 .gro_complete = tcp4_gro_complete,
328 },
329};
330
331int __init tcpv4_offload_init(void)
332{
333 return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
334}