net: wireless: bcmdhd: Put p2p_dev_addr under DHD_P2P_DEV_ADDR_FROM_SYSFS
[linux-2.6.git] / net / ipv4 / inet_lro.c
1 /*
2  *  linux/net/ipv4/inet_lro.c
3  *
4  *  Large Receive Offload (ipv4 / tcp)
5  *
6  *  (C) Copyright IBM Corp. 2007
7  *
8  *  Authors:
9  *       Jan-Bernd Themann <themann@de.ibm.com>
10  *       Christoph Raisch <raisch@de.ibm.com>
11  *
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2, or (at your option)
16  * any later version.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21  * GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with this program; if not, write to the Free Software
25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26  */
27
28
29 #include <linux/module.h>
30 #include <linux/if_vlan.h>
31 #include <linux/inet_lro.h>
32
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Jan-Bernd Themann <themann@de.ibm.com>");
35 MODULE_DESCRIPTION("Large Receive Offload (ipv4 / tcp)");
36
37 #define TCP_HDR_LEN(tcph) (tcph->doff << 2)
38 #define IP_HDR_LEN(iph) (iph->ihl << 2)
39 #define TCP_PAYLOAD_LENGTH(iph, tcph) \
40         (ntohs(iph->tot_len) - IP_HDR_LEN(iph) - TCP_HDR_LEN(tcph))
41
42 #define IPH_LEN_WO_OPTIONS 5
43 #define TCPH_LEN_WO_OPTIONS 5
44 #define TCPH_LEN_W_TIMESTAMP 8
45
46 #define LRO_MAX_PG_HLEN 64
47
48 #define LRO_INC_STATS(lro_mgr, attr) { lro_mgr->stats.attr++; }
49
50 /*
51  * Basic tcp checks whether packet is suitable for LRO
52  */
53
54 static int lro_tcp_ip_check(const struct iphdr *iph, const struct tcphdr *tcph,
55                             int len, const struct net_lro_desc *lro_desc)
56 {
57         /* check ip header: don't aggregate padded frames */
58         if (ntohs(iph->tot_len) != len)
59                 return -1;
60
61         if (TCP_PAYLOAD_LENGTH(iph, tcph) == 0)
62                 return -1;
63
64         if (iph->ihl != IPH_LEN_WO_OPTIONS)
65                 return -1;
66
67         if (tcph->cwr || tcph->ece || tcph->urg || !tcph->ack ||
68             tcph->rst || tcph->syn || tcph->fin)
69                 return -1;
70
71         if (INET_ECN_is_ce(ipv4_get_dsfield(iph)))
72                 return -1;
73
74         if (tcph->doff != TCPH_LEN_WO_OPTIONS &&
75             tcph->doff != TCPH_LEN_W_TIMESTAMP)
76                 return -1;
77
78         /* check tcp options (only timestamp allowed) */
79         if (tcph->doff == TCPH_LEN_W_TIMESTAMP) {
80                 __be32 *topt = (__be32 *)(tcph + 1);
81
82                 if (*topt != htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
83                                    | (TCPOPT_TIMESTAMP << 8)
84                                    | TCPOLEN_TIMESTAMP))
85                         return -1;
86
87                 /* timestamp should be in right order */
88                 topt++;
89                 if (lro_desc && after(ntohl(lro_desc->tcp_rcv_tsval),
90                                       ntohl(*topt)))
91                         return -1;
92
93                 /* timestamp reply should not be zero */
94                 topt++;
95                 if (*topt == 0)
96                         return -1;
97         }
98
99         return 0;
100 }
101
102 static void lro_update_tcp_ip_header(struct net_lro_desc *lro_desc)
103 {
104         struct iphdr *iph = lro_desc->iph;
105         struct tcphdr *tcph = lro_desc->tcph;
106         __be32 *p;
107         __wsum tcp_hdr_csum;
108
109         tcph->ack_seq = lro_desc->tcp_ack;
110         tcph->window = lro_desc->tcp_window;
111
112         if (lro_desc->tcp_saw_tstamp) {
113                 p = (__be32 *)(tcph + 1);
114                 *(p+2) = lro_desc->tcp_rcv_tsecr;
115         }
116
117         iph->tot_len = htons(lro_desc->ip_tot_len);
118
119         iph->check = 0;
120         iph->check = ip_fast_csum((u8 *)lro_desc->iph, iph->ihl);
121
122         tcph->check = 0;
123         tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), 0);
124         lro_desc->data_csum = csum_add(lro_desc->data_csum, tcp_hdr_csum);
125         tcph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
126                                         lro_desc->ip_tot_len -
127                                         IP_HDR_LEN(iph), IPPROTO_TCP,
128                                         lro_desc->data_csum);
129 }
130
131 static __wsum lro_tcp_data_csum(struct iphdr *iph, struct tcphdr *tcph, int len)
132 {
133         __wsum tcp_csum;
134         __wsum tcp_hdr_csum;
135         __wsum tcp_ps_hdr_csum;
136
137         tcp_csum = ~csum_unfold(tcph->check);
138         tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), tcp_csum);
139
140         tcp_ps_hdr_csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
141                                              len + TCP_HDR_LEN(tcph),
142                                              IPPROTO_TCP, 0);
143
144         return csum_sub(csum_sub(tcp_csum, tcp_hdr_csum),
145                         tcp_ps_hdr_csum);
146 }
147
148 static void lro_init_desc(struct net_lro_desc *lro_desc, struct sk_buff *skb,
149                           struct iphdr *iph, struct tcphdr *tcph)
150 {
151         int nr_frags;
152         __be32 *ptr;
153         u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
154
155         nr_frags = skb_shinfo(skb)->nr_frags;
156         lro_desc->parent = skb;
157         lro_desc->next_frag = &(skb_shinfo(skb)->frags[nr_frags]);
158         lro_desc->iph = iph;
159         lro_desc->tcph = tcph;
160         lro_desc->tcp_next_seq = ntohl(tcph->seq) + tcp_data_len;
161         lro_desc->tcp_ack = tcph->ack_seq;
162         lro_desc->tcp_window = tcph->window;
163
164         lro_desc->pkt_aggr_cnt = 1;
165         lro_desc->ip_tot_len = ntohs(iph->tot_len);
166
167         if (tcph->doff == 8) {
168                 ptr = (__be32 *)(tcph+1);
169                 lro_desc->tcp_saw_tstamp = 1;
170                 lro_desc->tcp_rcv_tsval = *(ptr+1);
171                 lro_desc->tcp_rcv_tsecr = *(ptr+2);
172         }
173
174         lro_desc->mss = tcp_data_len;
175         lro_desc->active = 1;
176
177         lro_desc->data_csum = lro_tcp_data_csum(iph, tcph,
178                                                 tcp_data_len);
179 }
180
181 static inline void lro_clear_desc(struct net_lro_desc *lro_desc)
182 {
183         memset(lro_desc, 0, sizeof(struct net_lro_desc));
184 }
185
186 static void lro_add_common(struct net_lro_desc *lro_desc, struct iphdr *iph,
187                            struct tcphdr *tcph, int tcp_data_len)
188 {
189         struct sk_buff *parent = lro_desc->parent;
190         __be32 *topt;
191
192         lro_desc->pkt_aggr_cnt++;
193         lro_desc->ip_tot_len += tcp_data_len;
194         lro_desc->tcp_next_seq += tcp_data_len;
195         lro_desc->tcp_window = tcph->window;
196         lro_desc->tcp_ack = tcph->ack_seq;
197
198         /* don't update tcp_rcv_tsval, would not work with PAWS */
199         if (lro_desc->tcp_saw_tstamp) {
200                 topt = (__be32 *) (tcph + 1);
201                 lro_desc->tcp_rcv_tsecr = *(topt + 2);
202         }
203
204         lro_desc->data_csum = csum_block_add(lro_desc->data_csum,
205                                              lro_tcp_data_csum(iph, tcph,
206                                                                tcp_data_len),
207                                              parent->len);
208
209         parent->len += tcp_data_len;
210         parent->data_len += tcp_data_len;
211         if (tcp_data_len > lro_desc->mss)
212                 lro_desc->mss = tcp_data_len;
213 }
214
215 static void lro_add_packet(struct net_lro_desc *lro_desc, struct sk_buff *skb,
216                            struct iphdr *iph, struct tcphdr *tcph)
217 {
218         struct sk_buff *parent = lro_desc->parent;
219         int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
220
221         lro_add_common(lro_desc, iph, tcph, tcp_data_len);
222
223         skb_pull(skb, (skb->len - tcp_data_len));
224         parent->truesize += skb->truesize;
225
226         if (lro_desc->last_skb)
227                 lro_desc->last_skb->next = skb;
228         else
229                 skb_shinfo(parent)->frag_list = skb;
230
231         lro_desc->last_skb = skb;
232 }
233
234 static void lro_add_frags(struct net_lro_desc *lro_desc,
235                           int len, int hlen, int truesize,
236                           struct skb_frag_struct *skb_frags,
237                           struct iphdr *iph, struct tcphdr *tcph)
238 {
239         struct sk_buff *skb = lro_desc->parent;
240         int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
241
242         lro_add_common(lro_desc, iph, tcph, tcp_data_len);
243
244         skb->truesize += truesize;
245
246         skb_frags[0].page_offset += hlen;
247         skb_frags[0].size -= hlen;
248
249         while (tcp_data_len > 0) {
250                 *(lro_desc->next_frag) = *skb_frags;
251                 tcp_data_len -= skb_frags->size;
252                 lro_desc->next_frag++;
253                 skb_frags++;
254                 skb_shinfo(skb)->nr_frags++;
255         }
256 }
257
258 static int lro_check_tcp_conn(struct net_lro_desc *lro_desc,
259                               struct iphdr *iph,
260                               struct tcphdr *tcph)
261 {
262         if ((lro_desc->iph->saddr != iph->saddr) ||
263             (lro_desc->iph->daddr != iph->daddr) ||
264             (lro_desc->tcph->source != tcph->source) ||
265             (lro_desc->tcph->dest != tcph->dest))
266                 return -1;
267         return 0;
268 }
269
270 static struct net_lro_desc *lro_get_desc(struct net_lro_mgr *lro_mgr,
271                                          struct net_lro_desc *lro_arr,
272                                          struct iphdr *iph,
273                                          struct tcphdr *tcph)
274 {
275         struct net_lro_desc *lro_desc = NULL;
276         struct net_lro_desc *tmp;
277         int max_desc = lro_mgr->max_desc;
278         int i;
279
280         for (i = 0; i < max_desc; i++) {
281                 tmp = &lro_arr[i];
282                 if (tmp->active)
283                         if (!lro_check_tcp_conn(tmp, iph, tcph)) {
284                                 lro_desc = tmp;
285                                 goto out;
286                         }
287         }
288
289         for (i = 0; i < max_desc; i++) {
290                 if (!lro_arr[i].active) {
291                         lro_desc = &lro_arr[i];
292                         goto out;
293                 }
294         }
295
296         LRO_INC_STATS(lro_mgr, no_desc);
297 out:
298         return lro_desc;
299 }
300
301 static void lro_flush(struct net_lro_mgr *lro_mgr,
302                       struct net_lro_desc *lro_desc)
303 {
304         if (lro_desc->pkt_aggr_cnt > 1)
305                 lro_update_tcp_ip_header(lro_desc);
306
307         skb_shinfo(lro_desc->parent)->gso_size = lro_desc->mss;
308
309         if (lro_mgr->features & LRO_F_NAPI)
310                 netif_receive_skb(lro_desc->parent);
311         else
312                 netif_rx(lro_desc->parent);
313
314         LRO_INC_STATS(lro_mgr, flushed);
315         lro_clear_desc(lro_desc);
316 }
317
318 static int __lro_proc_skb(struct net_lro_mgr *lro_mgr, struct sk_buff *skb,
319                           void *priv)
320 {
321         struct net_lro_desc *lro_desc;
322         struct iphdr *iph;
323         struct tcphdr *tcph;
324         u64 flags;
325         int vlan_hdr_len = 0;
326
327         if (!lro_mgr->get_skb_header ||
328             lro_mgr->get_skb_header(skb, (void *)&iph, (void *)&tcph,
329                                     &flags, priv))
330                 goto out;
331
332         if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
333                 goto out;
334
335         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
336         if (!lro_desc)
337                 goto out;
338
339         if ((skb->protocol == htons(ETH_P_8021Q)) &&
340             !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
341                 vlan_hdr_len = VLAN_HLEN;
342
343         if (!lro_desc->active) { /* start new lro session */
344                 if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, NULL))
345                         goto out;
346
347                 skb->ip_summed = lro_mgr->ip_summed_aggr;
348                 lro_init_desc(lro_desc, skb, iph, tcph);
349                 LRO_INC_STATS(lro_mgr, aggregated);
350                 return 0;
351         }
352
353         if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
354                 goto out2;
355
356         if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
357                 goto out2;
358
359         lro_add_packet(lro_desc, skb, iph, tcph);
360         LRO_INC_STATS(lro_mgr, aggregated);
361
362         if ((lro_desc->pkt_aggr_cnt >= lro_mgr->max_aggr) ||
363             lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
364                 lro_flush(lro_mgr, lro_desc);
365
366         return 0;
367
368 out2: /* send aggregated SKBs to stack */
369         lro_flush(lro_mgr, lro_desc);
370
371 out:
372         return 1;
373 }
374
375
376 static struct sk_buff *lro_gen_skb(struct net_lro_mgr *lro_mgr,
377                                    struct skb_frag_struct *frags,
378                                    int len, int true_size,
379                                    void *mac_hdr,
380                                    int hlen, __wsum sum,
381                                    u32 ip_summed)
382 {
383         struct sk_buff *skb;
384         struct skb_frag_struct *skb_frags;
385         int data_len = len;
386         int hdr_len = min(len, hlen);
387
388         skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
389         if (!skb)
390                 return NULL;
391
392         skb_reserve(skb, lro_mgr->frag_align_pad);
393         skb->len = len;
394         skb->data_len = len - hdr_len;
395         skb->truesize += true_size;
396         skb->tail += hdr_len;
397
398         memcpy(skb->data, mac_hdr, hdr_len);
399
400         skb_frags = skb_shinfo(skb)->frags;
401         while (data_len > 0) {
402                 *skb_frags = *frags;
403                 data_len -= frags->size;
404                 skb_frags++;
405                 frags++;
406                 skb_shinfo(skb)->nr_frags++;
407         }
408
409         skb_shinfo(skb)->frags[0].page_offset += hdr_len;
410         skb_shinfo(skb)->frags[0].size -= hdr_len;
411
412         skb->ip_summed = ip_summed;
413         skb->csum = sum;
414         skb->protocol = eth_type_trans(skb, lro_mgr->dev);
415         return skb;
416 }
417
418 static struct sk_buff *__lro_proc_segment(struct net_lro_mgr *lro_mgr,
419                                           struct skb_frag_struct *frags,
420                                           int len, int true_size,
421                                           void *priv, __wsum sum)
422 {
423         struct net_lro_desc *lro_desc;
424         struct iphdr *iph;
425         struct tcphdr *tcph;
426         struct sk_buff *skb;
427         u64 flags;
428         void *mac_hdr;
429         int mac_hdr_len;
430         int hdr_len = LRO_MAX_PG_HLEN;
431         int vlan_hdr_len = 0;
432
433         if (!lro_mgr->get_frag_header ||
434             lro_mgr->get_frag_header(frags, (void *)&mac_hdr, (void *)&iph,
435                                      (void *)&tcph, &flags, priv)) {
436                 mac_hdr = page_address(frags->page) + frags->page_offset;
437                 goto out1;
438         }
439
440         if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
441                 goto out1;
442
443         hdr_len = (int)((void *)(tcph) + TCP_HDR_LEN(tcph) - mac_hdr);
444         mac_hdr_len = (int)((void *)(iph) - mac_hdr);
445
446         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
447         if (!lro_desc)
448                 goto out1;
449
450         if (!lro_desc->active) { /* start new lro session */
451                 if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, NULL))
452                         goto out1;
453
454                 skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
455                                   hdr_len, 0, lro_mgr->ip_summed_aggr);
456                 if (!skb)
457                         goto out;
458
459                 if ((skb->protocol == htons(ETH_P_8021Q)) &&
460                     !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
461                         vlan_hdr_len = VLAN_HLEN;
462
463                 iph = (void *)(skb->data + vlan_hdr_len);
464                 tcph = (void *)((u8 *)skb->data + vlan_hdr_len
465                                 + IP_HDR_LEN(iph));
466
467                 lro_init_desc(lro_desc, skb, iph, tcph);
468                 LRO_INC_STATS(lro_mgr, aggregated);
469                 return NULL;
470         }
471
472         if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
473                 goto out2;
474
475         if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, lro_desc))
476                 goto out2;
477
478         lro_add_frags(lro_desc, len, hdr_len, true_size, frags, iph, tcph);
479         LRO_INC_STATS(lro_mgr, aggregated);
480
481         if ((skb_shinfo(lro_desc->parent)->nr_frags >= lro_mgr->max_aggr) ||
482             lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
483                 lro_flush(lro_mgr, lro_desc);
484
485         return NULL;
486
487 out2: /* send aggregated packets to the stack */
488         lro_flush(lro_mgr, lro_desc);
489
490 out1:  /* Original packet has to be posted to the stack */
491         skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
492                           hdr_len, sum, lro_mgr->ip_summed);
493 out:
494         return skb;
495 }
496
497 void lro_receive_skb(struct net_lro_mgr *lro_mgr,
498                      struct sk_buff *skb,
499                      void *priv)
500 {
501         if (__lro_proc_skb(lro_mgr, skb, priv)) {
502                 if (lro_mgr->features & LRO_F_NAPI)
503                         netif_receive_skb(skb);
504                 else
505                         netif_rx(skb);
506         }
507 }
508 EXPORT_SYMBOL(lro_receive_skb);
509
510 void lro_receive_frags(struct net_lro_mgr *lro_mgr,
511                        struct skb_frag_struct *frags,
512                        int len, int true_size, void *priv, __wsum sum)
513 {
514         struct sk_buff *skb;
515
516         skb = __lro_proc_segment(lro_mgr, frags, len, true_size, priv, sum);
517         if (!skb)
518                 return;
519
520         if (lro_mgr->features & LRO_F_NAPI)
521                 netif_receive_skb(skb);
522         else
523                 netif_rx(skb);
524 }
525 EXPORT_SYMBOL(lro_receive_frags);
526
527 void lro_flush_all(struct net_lro_mgr *lro_mgr)
528 {
529         int i;
530         struct net_lro_desc *lro_desc = lro_mgr->lro_arr;
531
532         for (i = 0; i < lro_mgr->max_desc; i++) {
533                 if (lro_desc[i].active)
534                         lro_flush(lro_mgr, &lro_desc[i]);
535         }
536 }
537 EXPORT_SYMBOL(lro_flush_all);
538
539 void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
540                   struct iphdr *iph, struct tcphdr *tcph)
541 {
542         struct net_lro_desc *lro_desc;
543
544         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
545         if (lro_desc->active)
546                 lro_flush(lro_mgr, lro_desc);
547 }
548 EXPORT_SYMBOL(lro_flush_pkt);