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Linux/net/openvswitch/actions.c

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  1 /*
  2  * Copyright (c) 2007-2014 Nicira, Inc.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of version 2 of the GNU General Public
  6  * License as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful, but
  9  * WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public License
 14  * along with this program; if not, write to the Free Software
 15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 16  * 02110-1301, USA
 17  */
 18 
 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 20 
 21 #include <linux/skbuff.h>
 22 #include <linux/in.h>
 23 #include <linux/ip.h>
 24 #include <linux/openvswitch.h>
 25 #include <linux/netfilter_ipv6.h>
 26 #include <linux/sctp.h>
 27 #include <linux/tcp.h>
 28 #include <linux/udp.h>
 29 #include <linux/in6.h>
 30 #include <linux/if_arp.h>
 31 #include <linux/if_vlan.h>
 32 
 33 #include <net/dst.h>
 34 #include <net/ip.h>
 35 #include <net/ipv6.h>
 36 #include <net/ip6_fib.h>
 37 #include <net/checksum.h>
 38 #include <net/dsfield.h>
 39 #include <net/mpls.h>
 40 #include <net/sctp/checksum.h>
 41 
 42 #include "datapath.h"
 43 #include "flow.h"
 44 #include "conntrack.h"
 45 #include "vport.h"
 46 
 47 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 48                               struct sw_flow_key *key,
 49                               const struct nlattr *attr, int len);
 50 
 51 struct deferred_action {
 52         struct sk_buff *skb;
 53         const struct nlattr *actions;
 54 
 55         /* Store pkt_key clone when creating deferred action. */
 56         struct sw_flow_key pkt_key;
 57 };
 58 
 59 #define MAX_L2_LEN      (VLAN_ETH_HLEN + 3 * MPLS_HLEN)
 60 struct ovs_frag_data {
 61         unsigned long dst;
 62         struct vport *vport;
 63         struct ovs_skb_cb cb;
 64         __be16 inner_protocol;
 65         __u16 vlan_tci;
 66         __be16 vlan_proto;
 67         unsigned int l2_len;
 68         u8 l2_data[MAX_L2_LEN];
 69 };
 70 
 71 static DEFINE_PER_CPU(struct ovs_frag_data, ovs_frag_data_storage);
 72 
 73 #define DEFERRED_ACTION_FIFO_SIZE 10
 74 struct action_fifo {
 75         int head;
 76         int tail;
 77         /* Deferred action fifo queue storage. */
 78         struct deferred_action fifo[DEFERRED_ACTION_FIFO_SIZE];
 79 };
 80 
 81 static struct action_fifo __percpu *action_fifos;
 82 static DEFINE_PER_CPU(int, exec_actions_level);
 83 
 84 static void action_fifo_init(struct action_fifo *fifo)
 85 {
 86         fifo->head = 0;
 87         fifo->tail = 0;
 88 }
 89 
 90 static bool action_fifo_is_empty(const struct action_fifo *fifo)
 91 {
 92         return (fifo->head == fifo->tail);
 93 }
 94 
 95 static struct deferred_action *action_fifo_get(struct action_fifo *fifo)
 96 {
 97         if (action_fifo_is_empty(fifo))
 98                 return NULL;
 99 
100         return &fifo->fifo[fifo->tail++];
101 }
102 
103 static struct deferred_action *action_fifo_put(struct action_fifo *fifo)
104 {
105         if (fifo->head >= DEFERRED_ACTION_FIFO_SIZE - 1)
106                 return NULL;
107 
108         return &fifo->fifo[fifo->head++];
109 }
110 
111 /* Return true if fifo is not full */
112 static struct deferred_action *add_deferred_actions(struct sk_buff *skb,
113                                                     const struct sw_flow_key *key,
114                                                     const struct nlattr *attr)
115 {
116         struct action_fifo *fifo;
117         struct deferred_action *da;
118 
119         fifo = this_cpu_ptr(action_fifos);
120         da = action_fifo_put(fifo);
121         if (da) {
122                 da->skb = skb;
123                 da->actions = attr;
124                 da->pkt_key = *key;
125         }
126 
127         return da;
128 }
129 
130 static void invalidate_flow_key(struct sw_flow_key *key)
131 {
132         key->eth.type = htons(0);
133 }
134 
135 static bool is_flow_key_valid(const struct sw_flow_key *key)
136 {
137         return !!key->eth.type;
138 }
139 
140 static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
141                      const struct ovs_action_push_mpls *mpls)
142 {
143         __be32 *new_mpls_lse;
144         struct ethhdr *hdr;
145 
146         /* Networking stack do not allow simultaneous Tunnel and MPLS GSO. */
147         if (skb->encapsulation)
148                 return -ENOTSUPP;
149 
150         if (skb_cow_head(skb, MPLS_HLEN) < 0)
151                 return -ENOMEM;
152 
153         skb_push(skb, MPLS_HLEN);
154         memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
155                 skb->mac_len);
156         skb_reset_mac_header(skb);
157 
158         new_mpls_lse = (__be32 *)skb_mpls_header(skb);
159         *new_mpls_lse = mpls->mpls_lse;
160 
161         skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
162 
163         hdr = eth_hdr(skb);
164         hdr->h_proto = mpls->mpls_ethertype;
165 
166         if (!skb->inner_protocol)
167                 skb_set_inner_protocol(skb, skb->protocol);
168         skb->protocol = mpls->mpls_ethertype;
169 
170         invalidate_flow_key(key);
171         return 0;
172 }
173 
174 static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
175                     const __be16 ethertype)
176 {
177         struct ethhdr *hdr;
178         int err;
179 
180         err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
181         if (unlikely(err))
182                 return err;
183 
184         skb_postpull_rcsum(skb, skb_mpls_header(skb), MPLS_HLEN);
185 
186         memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
187                 skb->mac_len);
188 
189         __skb_pull(skb, MPLS_HLEN);
190         skb_reset_mac_header(skb);
191 
192         /* skb_mpls_header() is used to locate the ethertype
193          * field correctly in the presence of VLAN tags.
194          */
195         hdr = (struct ethhdr *)(skb_mpls_header(skb) - ETH_HLEN);
196         hdr->h_proto = ethertype;
197         if (eth_p_mpls(skb->protocol))
198                 skb->protocol = ethertype;
199 
200         invalidate_flow_key(key);
201         return 0;
202 }
203 
204 static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key,
205                     const __be32 *mpls_lse, const __be32 *mask)
206 {
207         __be32 *stack;
208         __be32 lse;
209         int err;
210 
211         err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
212         if (unlikely(err))
213                 return err;
214 
215         stack = (__be32 *)skb_mpls_header(skb);
216         lse = OVS_MASKED(*stack, *mpls_lse, *mask);
217         if (skb->ip_summed == CHECKSUM_COMPLETE) {
218                 __be32 diff[] = { ~(*stack), lse };
219 
220                 skb->csum = ~csum_partial((char *)diff, sizeof(diff),
221                                           ~skb->csum);
222         }
223 
224         *stack = lse;
225         flow_key->mpls.top_lse = lse;
226         return 0;
227 }
228 
229 static int pop_vlan(struct sk_buff *skb, struct sw_flow_key *key)
230 {
231         int err;
232 
233         err = skb_vlan_pop(skb);
234         if (skb_vlan_tag_present(skb))
235                 invalidate_flow_key(key);
236         else
237                 key->eth.tci = 0;
238         return err;
239 }
240 
241 static int push_vlan(struct sk_buff *skb, struct sw_flow_key *key,
242                      const struct ovs_action_push_vlan *vlan)
243 {
244         if (skb_vlan_tag_present(skb))
245                 invalidate_flow_key(key);
246         else
247                 key->eth.tci = vlan->vlan_tci;
248         return skb_vlan_push(skb, vlan->vlan_tpid,
249                              ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
250 }
251 
252 /* 'src' is already properly masked. */
253 static void ether_addr_copy_masked(u8 *dst_, const u8 *src_, const u8 *mask_)
254 {
255         u16 *dst = (u16 *)dst_;
256         const u16 *src = (const u16 *)src_;
257         const u16 *mask = (const u16 *)mask_;
258 
259         OVS_SET_MASKED(dst[0], src[0], mask[0]);
260         OVS_SET_MASKED(dst[1], src[1], mask[1]);
261         OVS_SET_MASKED(dst[2], src[2], mask[2]);
262 }
263 
264 static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *flow_key,
265                         const struct ovs_key_ethernet *key,
266                         const struct ovs_key_ethernet *mask)
267 {
268         int err;
269 
270         err = skb_ensure_writable(skb, ETH_HLEN);
271         if (unlikely(err))
272                 return err;
273 
274         skb_postpull_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
275 
276         ether_addr_copy_masked(eth_hdr(skb)->h_source, key->eth_src,
277                                mask->eth_src);
278         ether_addr_copy_masked(eth_hdr(skb)->h_dest, key->eth_dst,
279                                mask->eth_dst);
280 
281         skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
282 
283         ether_addr_copy(flow_key->eth.src, eth_hdr(skb)->h_source);
284         ether_addr_copy(flow_key->eth.dst, eth_hdr(skb)->h_dest);
285         return 0;
286 }
287 
288 static void update_ip_l4_checksum(struct sk_buff *skb, struct iphdr *nh,
289                                   __be32 addr, __be32 new_addr)
290 {
291         int transport_len = skb->len - skb_transport_offset(skb);
292 
293         if (nh->frag_off & htons(IP_OFFSET))
294                 return;
295 
296         if (nh->protocol == IPPROTO_TCP) {
297                 if (likely(transport_len >= sizeof(struct tcphdr)))
298                         inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
299                                                  addr, new_addr, true);
300         } else if (nh->protocol == IPPROTO_UDP) {
301                 if (likely(transport_len >= sizeof(struct udphdr))) {
302                         struct udphdr *uh = udp_hdr(skb);
303 
304                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
305                                 inet_proto_csum_replace4(&uh->check, skb,
306                                                          addr, new_addr, true);
307                                 if (!uh->check)
308                                         uh->check = CSUM_MANGLED_0;
309                         }
310                 }
311         }
312 }
313 
314 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
315                         __be32 *addr, __be32 new_addr)
316 {
317         update_ip_l4_checksum(skb, nh, *addr, new_addr);
318         csum_replace4(&nh->check, *addr, new_addr);
319         skb_clear_hash(skb);
320         *addr = new_addr;
321 }
322 
323 static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
324                                  __be32 addr[4], const __be32 new_addr[4])
325 {
326         int transport_len = skb->len - skb_transport_offset(skb);
327 
328         if (l4_proto == NEXTHDR_TCP) {
329                 if (likely(transport_len >= sizeof(struct tcphdr)))
330                         inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
331                                                   addr, new_addr, true);
332         } else if (l4_proto == NEXTHDR_UDP) {
333                 if (likely(transport_len >= sizeof(struct udphdr))) {
334                         struct udphdr *uh = udp_hdr(skb);
335 
336                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
337                                 inet_proto_csum_replace16(&uh->check, skb,
338                                                           addr, new_addr, true);
339                                 if (!uh->check)
340                                         uh->check = CSUM_MANGLED_0;
341                         }
342                 }
343         } else if (l4_proto == NEXTHDR_ICMP) {
344                 if (likely(transport_len >= sizeof(struct icmp6hdr)))
345                         inet_proto_csum_replace16(&icmp6_hdr(skb)->icmp6_cksum,
346                                                   skb, addr, new_addr, true);
347         }
348 }
349 
350 static void mask_ipv6_addr(const __be32 old[4], const __be32 addr[4],
351                            const __be32 mask[4], __be32 masked[4])
352 {
353         masked[0] = OVS_MASKED(old[0], addr[0], mask[0]);
354         masked[1] = OVS_MASKED(old[1], addr[1], mask[1]);
355         masked[2] = OVS_MASKED(old[2], addr[2], mask[2]);
356         masked[3] = OVS_MASKED(old[3], addr[3], mask[3]);
357 }
358 
359 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
360                           __be32 addr[4], const __be32 new_addr[4],
361                           bool recalculate_csum)
362 {
363         if (recalculate_csum)
364                 update_ipv6_checksum(skb, l4_proto, addr, new_addr);
365 
366         skb_clear_hash(skb);
367         memcpy(addr, new_addr, sizeof(__be32[4]));
368 }
369 
370 static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl, u32 mask)
371 {
372         /* Bits 21-24 are always unmasked, so this retains their values. */
373         OVS_SET_MASKED(nh->flow_lbl[0], (u8)(fl >> 16), (u8)(mask >> 16));
374         OVS_SET_MASKED(nh->flow_lbl[1], (u8)(fl >> 8), (u8)(mask >> 8));
375         OVS_SET_MASKED(nh->flow_lbl[2], (u8)fl, (u8)mask);
376 }
377 
378 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl,
379                        u8 mask)
380 {
381         new_ttl = OVS_MASKED(nh->ttl, new_ttl, mask);
382 
383         csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
384         nh->ttl = new_ttl;
385 }
386 
387 static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *flow_key,
388                     const struct ovs_key_ipv4 *key,
389                     const struct ovs_key_ipv4 *mask)
390 {
391         struct iphdr *nh;
392         __be32 new_addr;
393         int err;
394 
395         err = skb_ensure_writable(skb, skb_network_offset(skb) +
396                                   sizeof(struct iphdr));
397         if (unlikely(err))
398                 return err;
399 
400         nh = ip_hdr(skb);
401 
402         /* Setting an IP addresses is typically only a side effect of
403          * matching on them in the current userspace implementation, so it
404          * makes sense to check if the value actually changed.
405          */
406         if (mask->ipv4_src) {
407                 new_addr = OVS_MASKED(nh->saddr, key->ipv4_src, mask->ipv4_src);
408 
409                 if (unlikely(new_addr != nh->saddr)) {
410                         set_ip_addr(skb, nh, &nh->saddr, new_addr);
411                         flow_key->ipv4.addr.src = new_addr;
412                 }
413         }
414         if (mask->ipv4_dst) {
415                 new_addr = OVS_MASKED(nh->daddr, key->ipv4_dst, mask->ipv4_dst);
416 
417                 if (unlikely(new_addr != nh->daddr)) {
418                         set_ip_addr(skb, nh, &nh->daddr, new_addr);
419                         flow_key->ipv4.addr.dst = new_addr;
420                 }
421         }
422         if (mask->ipv4_tos) {
423                 ipv4_change_dsfield(nh, ~mask->ipv4_tos, key->ipv4_tos);
424                 flow_key->ip.tos = nh->tos;
425         }
426         if (mask->ipv4_ttl) {
427                 set_ip_ttl(skb, nh, key->ipv4_ttl, mask->ipv4_ttl);
428                 flow_key->ip.ttl = nh->ttl;
429         }
430 
431         return 0;
432 }
433 
434 static bool is_ipv6_mask_nonzero(const __be32 addr[4])
435 {
436         return !!(addr[0] | addr[1] | addr[2] | addr[3]);
437 }
438 
439 static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *flow_key,
440                     const struct ovs_key_ipv6 *key,
441                     const struct ovs_key_ipv6 *mask)
442 {
443         struct ipv6hdr *nh;
444         int err;
445 
446         err = skb_ensure_writable(skb, skb_network_offset(skb) +
447                                   sizeof(struct ipv6hdr));
448         if (unlikely(err))
449                 return err;
450 
451         nh = ipv6_hdr(skb);
452 
453         /* Setting an IP addresses is typically only a side effect of
454          * matching on them in the current userspace implementation, so it
455          * makes sense to check if the value actually changed.
456          */
457         if (is_ipv6_mask_nonzero(mask->ipv6_src)) {
458                 __be32 *saddr = (__be32 *)&nh->saddr;
459                 __be32 masked[4];
460 
461                 mask_ipv6_addr(saddr, key->ipv6_src, mask->ipv6_src, masked);
462 
463                 if (unlikely(memcmp(saddr, masked, sizeof(masked)))) {
464                         set_ipv6_addr(skb, flow_key->ip.proto, saddr, masked,
465                                       true);
466                         memcpy(&flow_key->ipv6.addr.src, masked,
467                                sizeof(flow_key->ipv6.addr.src));
468                 }
469         }
470         if (is_ipv6_mask_nonzero(mask->ipv6_dst)) {
471                 unsigned int offset = 0;
472                 int flags = IP6_FH_F_SKIP_RH;
473                 bool recalc_csum = true;
474                 __be32 *daddr = (__be32 *)&nh->daddr;
475                 __be32 masked[4];
476 
477                 mask_ipv6_addr(daddr, key->ipv6_dst, mask->ipv6_dst, masked);
478 
479                 if (unlikely(memcmp(daddr, masked, sizeof(masked)))) {
480                         if (ipv6_ext_hdr(nh->nexthdr))
481                                 recalc_csum = (ipv6_find_hdr(skb, &offset,
482                                                              NEXTHDR_ROUTING,
483                                                              NULL, &flags)
484                                                != NEXTHDR_ROUTING);
485 
486                         set_ipv6_addr(skb, flow_key->ip.proto, daddr, masked,
487                                       recalc_csum);
488                         memcpy(&flow_key->ipv6.addr.dst, masked,
489                                sizeof(flow_key->ipv6.addr.dst));
490                 }
491         }
492         if (mask->ipv6_tclass) {
493                 ipv6_change_dsfield(nh, ~mask->ipv6_tclass, key->ipv6_tclass);
494                 flow_key->ip.tos = ipv6_get_dsfield(nh);
495         }
496         if (mask->ipv6_label) {
497                 set_ipv6_fl(nh, ntohl(key->ipv6_label),
498                             ntohl(mask->ipv6_label));
499                 flow_key->ipv6.label =
500                     *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
501         }
502         if (mask->ipv6_hlimit) {
503                 OVS_SET_MASKED(nh->hop_limit, key->ipv6_hlimit,
504                                mask->ipv6_hlimit);
505                 flow_key->ip.ttl = nh->hop_limit;
506         }
507         return 0;
508 }
509 
510 /* Must follow skb_ensure_writable() since that can move the skb data. */
511 static void set_tp_port(struct sk_buff *skb, __be16 *port,
512                         __be16 new_port, __sum16 *check)
513 {
514         inet_proto_csum_replace2(check, skb, *port, new_port, false);
515         *port = new_port;
516 }
517 
518 static int set_udp(struct sk_buff *skb, struct sw_flow_key *flow_key,
519                    const struct ovs_key_udp *key,
520                    const struct ovs_key_udp *mask)
521 {
522         struct udphdr *uh;
523         __be16 src, dst;
524         int err;
525 
526         err = skb_ensure_writable(skb, skb_transport_offset(skb) +
527                                   sizeof(struct udphdr));
528         if (unlikely(err))
529                 return err;
530 
531         uh = udp_hdr(skb);
532         /* Either of the masks is non-zero, so do not bother checking them. */
533         src = OVS_MASKED(uh->source, key->udp_src, mask->udp_src);
534         dst = OVS_MASKED(uh->dest, key->udp_dst, mask->udp_dst);
535 
536         if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
537                 if (likely(src != uh->source)) {
538                         set_tp_port(skb, &uh->source, src, &uh->check);
539                         flow_key->tp.src = src;
540                 }
541                 if (likely(dst != uh->dest)) {
542                         set_tp_port(skb, &uh->dest, dst, &uh->check);
543                         flow_key->tp.dst = dst;
544                 }
545 
546                 if (unlikely(!uh->check))
547                         uh->check = CSUM_MANGLED_0;
548         } else {
549                 uh->source = src;
550                 uh->dest = dst;
551                 flow_key->tp.src = src;
552                 flow_key->tp.dst = dst;
553         }
554 
555         skb_clear_hash(skb);
556 
557         return 0;
558 }
559 
560 static int set_tcp(struct sk_buff *skb, struct sw_flow_key *flow_key,
561                    const struct ovs_key_tcp *key,
562                    const struct ovs_key_tcp *mask)
563 {
564         struct tcphdr *th;
565         __be16 src, dst;
566         int err;
567 
568         err = skb_ensure_writable(skb, skb_transport_offset(skb) +
569                                   sizeof(struct tcphdr));
570         if (unlikely(err))
571                 return err;
572 
573         th = tcp_hdr(skb);
574         src = OVS_MASKED(th->source, key->tcp_src, mask->tcp_src);
575         if (likely(src != th->source)) {
576                 set_tp_port(skb, &th->source, src, &th->check);
577                 flow_key->tp.src = src;
578         }
579         dst = OVS_MASKED(th->dest, key->tcp_dst, mask->tcp_dst);
580         if (likely(dst != th->dest)) {
581                 set_tp_port(skb, &th->dest, dst, &th->check);
582                 flow_key->tp.dst = dst;
583         }
584         skb_clear_hash(skb);
585 
586         return 0;
587 }
588 
589 static int set_sctp(struct sk_buff *skb, struct sw_flow_key *flow_key,
590                     const struct ovs_key_sctp *key,
591                     const struct ovs_key_sctp *mask)
592 {
593         unsigned int sctphoff = skb_transport_offset(skb);
594         struct sctphdr *sh;
595         __le32 old_correct_csum, new_csum, old_csum;
596         int err;
597 
598         err = skb_ensure_writable(skb, sctphoff + sizeof(struct sctphdr));
599         if (unlikely(err))
600                 return err;
601 
602         sh = sctp_hdr(skb);
603         old_csum = sh->checksum;
604         old_correct_csum = sctp_compute_cksum(skb, sctphoff);
605 
606         sh->source = OVS_MASKED(sh->source, key->sctp_src, mask->sctp_src);
607         sh->dest = OVS_MASKED(sh->dest, key->sctp_dst, mask->sctp_dst);
608 
609         new_csum = sctp_compute_cksum(skb, sctphoff);
610 
611         /* Carry any checksum errors through. */
612         sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
613 
614         skb_clear_hash(skb);
615         flow_key->tp.src = sh->source;
616         flow_key->tp.dst = sh->dest;
617 
618         return 0;
619 }
620 
621 static int ovs_vport_output(struct net *net, struct sock *sk, struct sk_buff *skb)
622 {
623         struct ovs_frag_data *data = this_cpu_ptr(&ovs_frag_data_storage);
624         struct vport *vport = data->vport;
625 
626         if (skb_cow_head(skb, data->l2_len) < 0) {
627                 kfree_skb(skb);
628                 return -ENOMEM;
629         }
630 
631         __skb_dst_copy(skb, data->dst);
632         *OVS_CB(skb) = data->cb;
633         skb->inner_protocol = data->inner_protocol;
634         skb->vlan_tci = data->vlan_tci;
635         skb->vlan_proto = data->vlan_proto;
636 
637         /* Reconstruct the MAC header.  */
638         skb_push(skb, data->l2_len);
639         memcpy(skb->data, &data->l2_data, data->l2_len);
640         skb_postpush_rcsum(skb, skb->data, data->l2_len);
641         skb_reset_mac_header(skb);
642 
643         ovs_vport_send(vport, skb);
644         return 0;
645 }
646 
647 static unsigned int
648 ovs_dst_get_mtu(const struct dst_entry *dst)
649 {
650         return dst->dev->mtu;
651 }
652 
653 static struct dst_ops ovs_dst_ops = {
654         .family = AF_UNSPEC,
655         .mtu = ovs_dst_get_mtu,
656 };
657 
658 /* prepare_frag() is called once per (larger-than-MTU) frame; its inverse is
659  * ovs_vport_output(), which is called once per fragmented packet.
660  */
661 static void prepare_frag(struct vport *vport, struct sk_buff *skb)
662 {
663         unsigned int hlen = skb_network_offset(skb);
664         struct ovs_frag_data *data;
665 
666         data = this_cpu_ptr(&ovs_frag_data_storage);
667         data->dst = skb->_skb_refdst;
668         data->vport = vport;
669         data->cb = *OVS_CB(skb);
670         data->inner_protocol = skb->inner_protocol;
671         data->vlan_tci = skb->vlan_tci;
672         data->vlan_proto = skb->vlan_proto;
673         data->l2_len = hlen;
674         memcpy(&data->l2_data, skb->data, hlen);
675 
676         memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
677         skb_pull(skb, hlen);
678 }
679 
680 static void ovs_fragment(struct net *net, struct vport *vport,
681                          struct sk_buff *skb, u16 mru, __be16 ethertype)
682 {
683         if (skb_network_offset(skb) > MAX_L2_LEN) {
684                 OVS_NLERR(1, "L2 header too long to fragment");
685                 goto err;
686         }
687 
688         if (ethertype == htons(ETH_P_IP)) {
689                 struct dst_entry ovs_dst;
690                 unsigned long orig_dst;
691 
692                 prepare_frag(vport, skb);
693                 dst_init(&ovs_dst, &ovs_dst_ops, NULL, 1,
694                          DST_OBSOLETE_NONE, DST_NOCOUNT);
695                 ovs_dst.dev = vport->dev;
696 
697                 orig_dst = skb->_skb_refdst;
698                 skb_dst_set_noref(skb, &ovs_dst);
699                 IPCB(skb)->frag_max_size = mru;
700 
701                 ip_do_fragment(net, skb->sk, skb, ovs_vport_output);
702                 refdst_drop(orig_dst);
703         } else if (ethertype == htons(ETH_P_IPV6)) {
704                 const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
705                 unsigned long orig_dst;
706                 struct rt6_info ovs_rt;
707 
708                 if (!v6ops) {
709                         goto err;
710                 }
711 
712                 prepare_frag(vport, skb);
713                 memset(&ovs_rt, 0, sizeof(ovs_rt));
714                 dst_init(&ovs_rt.dst, &ovs_dst_ops, NULL, 1,
715                          DST_OBSOLETE_NONE, DST_NOCOUNT);
716                 ovs_rt.dst.dev = vport->dev;
717 
718                 orig_dst = skb->_skb_refdst;
719                 skb_dst_set_noref(skb, &ovs_rt.dst);
720                 IP6CB(skb)->frag_max_size = mru;
721 
722                 v6ops->fragment(net, skb->sk, skb, ovs_vport_output);
723                 refdst_drop(orig_dst);
724         } else {
725                 WARN_ONCE(1, "Failed fragment ->%s: eth=%04x, MRU=%d, MTU=%d.",
726                           ovs_vport_name(vport), ntohs(ethertype), mru,
727                           vport->dev->mtu);
728                 goto err;
729         }
730 
731         return;
732 err:
733         kfree_skb(skb);
734 }
735 
736 static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
737                       struct sw_flow_key *key)
738 {
739         struct vport *vport = ovs_vport_rcu(dp, out_port);
740 
741         if (likely(vport)) {
742                 u16 mru = OVS_CB(skb)->mru;
743 
744                 if (likely(!mru || (skb->len <= mru + ETH_HLEN))) {
745                         ovs_vport_send(vport, skb);
746                 } else if (mru <= vport->dev->mtu) {
747                         struct net *net = read_pnet(&dp->net);
748                         __be16 ethertype = key->eth.type;
749 
750                         if (!is_flow_key_valid(key)) {
751                                 if (eth_p_mpls(skb->protocol))
752                                         ethertype = skb->inner_protocol;
753                                 else
754                                         ethertype = vlan_get_protocol(skb);
755                         }
756 
757                         ovs_fragment(net, vport, skb, mru, ethertype);
758                 } else {
759                         kfree_skb(skb);
760                 }
761         } else {
762                 kfree_skb(skb);
763         }
764 }
765 
766 static int output_userspace(struct datapath *dp, struct sk_buff *skb,
767                             struct sw_flow_key *key, const struct nlattr *attr,
768                             const struct nlattr *actions, int actions_len)
769 {
770         struct dp_upcall_info upcall;
771         const struct nlattr *a;
772         int rem;
773 
774         memset(&upcall, 0, sizeof(upcall));
775         upcall.cmd = OVS_PACKET_CMD_ACTION;
776         upcall.mru = OVS_CB(skb)->mru;
777 
778         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
779                  a = nla_next(a, &rem)) {
780                 switch (nla_type(a)) {
781                 case OVS_USERSPACE_ATTR_USERDATA:
782                         upcall.userdata = a;
783                         break;
784 
785                 case OVS_USERSPACE_ATTR_PID:
786                         upcall.portid = nla_get_u32(a);
787                         break;
788 
789                 case OVS_USERSPACE_ATTR_EGRESS_TUN_PORT: {
790                         /* Get out tunnel info. */
791                         struct vport *vport;
792 
793                         vport = ovs_vport_rcu(dp, nla_get_u32(a));
794                         if (vport) {
795                                 int err;
796 
797                                 err = dev_fill_metadata_dst(vport->dev, skb);
798                                 if (!err)
799                                         upcall.egress_tun_info = skb_tunnel_info(skb);
800                         }
801 
802                         break;
803                 }
804 
805                 case OVS_USERSPACE_ATTR_ACTIONS: {
806                         /* Include actions. */
807                         upcall.actions = actions;
808                         upcall.actions_len = actions_len;
809                         break;
810                 }
811 
812                 } /* End of switch. */
813         }
814 
815         return ovs_dp_upcall(dp, skb, key, &upcall);
816 }
817 
818 static int sample(struct datapath *dp, struct sk_buff *skb,
819                   struct sw_flow_key *key, const struct nlattr *attr,
820                   const struct nlattr *actions, int actions_len)
821 {
822         const struct nlattr *acts_list = NULL;
823         const struct nlattr *a;
824         int rem;
825 
826         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
827                  a = nla_next(a, &rem)) {
828                 u32 probability;
829 
830                 switch (nla_type(a)) {
831                 case OVS_SAMPLE_ATTR_PROBABILITY:
832                         probability = nla_get_u32(a);
833                         if (!probability || prandom_u32() > probability)
834                                 return 0;
835                         break;
836 
837                 case OVS_SAMPLE_ATTR_ACTIONS:
838                         acts_list = a;
839                         break;
840                 }
841         }
842 
843         rem = nla_len(acts_list);
844         a = nla_data(acts_list);
845 
846         /* Actions list is empty, do nothing */
847         if (unlikely(!rem))
848                 return 0;
849 
850         /* The only known usage of sample action is having a single user-space
851          * action. Treat this usage as a special case.
852          * The output_userspace() should clone the skb to be sent to the
853          * user space. This skb will be consumed by its caller.
854          */
855         if (likely(nla_type(a) == OVS_ACTION_ATTR_USERSPACE &&
856                    nla_is_last(a, rem)))
857                 return output_userspace(dp, skb, key, a, actions, actions_len);
858 
859         skb = skb_clone(skb, GFP_ATOMIC);
860         if (!skb)
861                 /* Skip the sample action when out of memory. */
862                 return 0;
863 
864         if (!add_deferred_actions(skb, key, a)) {
865                 if (net_ratelimit())
866                         pr_warn("%s: deferred actions limit reached, dropping sample action\n",
867                                 ovs_dp_name(dp));
868 
869                 kfree_skb(skb);
870         }
871         return 0;
872 }
873 
874 static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
875                          const struct nlattr *attr)
876 {
877         struct ovs_action_hash *hash_act = nla_data(attr);
878         u32 hash = 0;
879 
880         /* OVS_HASH_ALG_L4 is the only possible hash algorithm.  */
881         hash = skb_get_hash(skb);
882         hash = jhash_1word(hash, hash_act->hash_basis);
883         if (!hash)
884                 hash = 0x1;
885 
886         key->ovs_flow_hash = hash;
887 }
888 
889 static int execute_set_action(struct sk_buff *skb,
890                               struct sw_flow_key *flow_key,
891                               const struct nlattr *a)
892 {
893         /* Only tunnel set execution is supported without a mask. */
894         if (nla_type(a) == OVS_KEY_ATTR_TUNNEL_INFO) {
895                 struct ovs_tunnel_info *tun = nla_data(a);
896 
897                 skb_dst_drop(skb);
898                 dst_hold((struct dst_entry *)tun->tun_dst);
899                 skb_dst_set(skb, (struct dst_entry *)tun->tun_dst);
900                 return 0;
901         }
902 
903         return -EINVAL;
904 }
905 
906 /* Mask is at the midpoint of the data. */
907 #define get_mask(a, type) ((const type)nla_data(a) + 1)
908 
909 static int execute_masked_set_action(struct sk_buff *skb,
910                                      struct sw_flow_key *flow_key,
911                                      const struct nlattr *a)
912 {
913         int err = 0;
914 
915         switch (nla_type(a)) {
916         case OVS_KEY_ATTR_PRIORITY:
917                 OVS_SET_MASKED(skb->priority, nla_get_u32(a),
918                                *get_mask(a, u32 *));
919                 flow_key->phy.priority = skb->priority;
920                 break;
921 
922         case OVS_KEY_ATTR_SKB_MARK:
923                 OVS_SET_MASKED(skb->mark, nla_get_u32(a), *get_mask(a, u32 *));
924                 flow_key->phy.skb_mark = skb->mark;
925                 break;
926 
927         case OVS_KEY_ATTR_TUNNEL_INFO:
928                 /* Masked data not supported for tunnel. */
929                 err = -EINVAL;
930                 break;
931 
932         case OVS_KEY_ATTR_ETHERNET:
933                 err = set_eth_addr(skb, flow_key, nla_data(a),
934                                    get_mask(a, struct ovs_key_ethernet *));
935                 break;
936 
937         case OVS_KEY_ATTR_IPV4:
938                 err = set_ipv4(skb, flow_key, nla_data(a),
939                                get_mask(a, struct ovs_key_ipv4 *));
940                 break;
941 
942         case OVS_KEY_ATTR_IPV6:
943                 err = set_ipv6(skb, flow_key, nla_data(a),
944                                get_mask(a, struct ovs_key_ipv6 *));
945                 break;
946 
947         case OVS_KEY_ATTR_TCP:
948                 err = set_tcp(skb, flow_key, nla_data(a),
949                               get_mask(a, struct ovs_key_tcp *));
950                 break;
951 
952         case OVS_KEY_ATTR_UDP:
953                 err = set_udp(skb, flow_key, nla_data(a),
954                               get_mask(a, struct ovs_key_udp *));
955                 break;
956 
957         case OVS_KEY_ATTR_SCTP:
958                 err = set_sctp(skb, flow_key, nla_data(a),
959                                get_mask(a, struct ovs_key_sctp *));
960                 break;
961 
962         case OVS_KEY_ATTR_MPLS:
963                 err = set_mpls(skb, flow_key, nla_data(a), get_mask(a,
964                                                                     __be32 *));
965                 break;
966 
967         case OVS_KEY_ATTR_CT_STATE:
968         case OVS_KEY_ATTR_CT_ZONE:
969         case OVS_KEY_ATTR_CT_MARK:
970         case OVS_KEY_ATTR_CT_LABELS:
971                 err = -EINVAL;
972                 break;
973         }
974 
975         return err;
976 }
977 
978 static int execute_recirc(struct datapath *dp, struct sk_buff *skb,
979                           struct sw_flow_key *key,
980                           const struct nlattr *a, int rem)
981 {
982         struct deferred_action *da;
983 
984         if (!is_flow_key_valid(key)) {
985                 int err;
986 
987                 err = ovs_flow_key_update(skb, key);
988                 if (err)
989                         return err;
990         }
991         BUG_ON(!is_flow_key_valid(key));
992 
993         if (!nla_is_last(a, rem)) {
994                 /* Recirc action is the not the last action
995                  * of the action list, need to clone the skb.
996                  */
997                 skb = skb_clone(skb, GFP_ATOMIC);
998 
999                 /* Skip the recirc action when out of memory, but
1000                  * continue on with the rest of the action list.
1001                  */
1002                 if (!skb)
1003                         return 0;
1004         }
1005 
1006         da = add_deferred_actions(skb, key, NULL);
1007         if (da) {
1008                 da->pkt_key.recirc_id = nla_get_u32(a);
1009         } else {
1010                 kfree_skb(skb);
1011 
1012                 if (net_ratelimit())
1013                         pr_warn("%s: deferred action limit reached, drop recirc action\n",
1014                                 ovs_dp_name(dp));
1015         }
1016 
1017         return 0;
1018 }
1019 
1020 /* Execute a list of actions against 'skb'. */
1021 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
1022                               struct sw_flow_key *key,
1023                               const struct nlattr *attr, int len)
1024 {
1025         /* Every output action needs a separate clone of 'skb', but the common
1026          * case is just a single output action, so that doing a clone and
1027          * then freeing the original skbuff is wasteful.  So the following code
1028          * is slightly obscure just to avoid that.
1029          */
1030         int prev_port = -1;
1031         const struct nlattr *a;
1032         int rem;
1033 
1034         for (a = attr, rem = len; rem > 0;
1035              a = nla_next(a, &rem)) {
1036                 int err = 0;
1037 
1038                 if (unlikely(prev_port != -1)) {
1039                         struct sk_buff *out_skb = skb_clone(skb, GFP_ATOMIC);
1040 
1041                         if (out_skb)
1042                                 do_output(dp, out_skb, prev_port, key);
1043 
1044                         prev_port = -1;
1045                 }
1046 
1047                 switch (nla_type(a)) {
1048                 case OVS_ACTION_ATTR_OUTPUT:
1049                         prev_port = nla_get_u32(a);
1050                         break;
1051 
1052                 case OVS_ACTION_ATTR_USERSPACE:
1053                         output_userspace(dp, skb, key, a, attr, len);
1054                         break;
1055 
1056                 case OVS_ACTION_ATTR_HASH:
1057                         execute_hash(skb, key, a);
1058                         break;
1059 
1060                 case OVS_ACTION_ATTR_PUSH_MPLS:
1061                         err = push_mpls(skb, key, nla_data(a));
1062                         break;
1063 
1064                 case OVS_ACTION_ATTR_POP_MPLS:
1065                         err = pop_mpls(skb, key, nla_get_be16(a));
1066                         break;
1067 
1068                 case OVS_ACTION_ATTR_PUSH_VLAN:
1069                         err = push_vlan(skb, key, nla_data(a));
1070                         break;
1071 
1072                 case OVS_ACTION_ATTR_POP_VLAN:
1073                         err = pop_vlan(skb, key);
1074                         break;
1075 
1076                 case OVS_ACTION_ATTR_RECIRC:
1077                         err = execute_recirc(dp, skb, key, a, rem);
1078                         if (nla_is_last(a, rem)) {
1079                                 /* If this is the last action, the skb has
1080                                  * been consumed or freed.
1081                                  * Return immediately.
1082                                  */
1083                                 return err;
1084                         }
1085                         break;
1086 
1087                 case OVS_ACTION_ATTR_SET:
1088                         err = execute_set_action(skb, key, nla_data(a));
1089                         break;
1090 
1091                 case OVS_ACTION_ATTR_SET_MASKED:
1092                 case OVS_ACTION_ATTR_SET_TO_MASKED:
1093                         err = execute_masked_set_action(skb, key, nla_data(a));
1094                         break;
1095 
1096                 case OVS_ACTION_ATTR_SAMPLE:
1097                         err = sample(dp, skb, key, a, attr, len);
1098                         break;
1099 
1100                 case OVS_ACTION_ATTR_CT:
1101                         if (!is_flow_key_valid(key)) {
1102                                 err = ovs_flow_key_update(skb, key);
1103                                 if (err)
1104                                         return err;
1105                         }
1106 
1107                         err = ovs_ct_execute(ovs_dp_get_net(dp), skb, key,
1108                                              nla_data(a));
1109 
1110                         /* Hide stolen IP fragments from user space. */
1111                         if (err)
1112                                 return err == -EINPROGRESS ? 0 : err;
1113                         break;
1114                 }
1115 
1116                 if (unlikely(err)) {
1117                         kfree_skb(skb);
1118                         return err;
1119                 }
1120         }
1121 
1122         if (prev_port != -1)
1123                 do_output(dp, skb, prev_port, key);
1124         else
1125                 consume_skb(skb);
1126 
1127         return 0;
1128 }
1129 
1130 static void process_deferred_actions(struct datapath *dp)
1131 {
1132         struct action_fifo *fifo = this_cpu_ptr(action_fifos);
1133 
1134         /* Do not touch the FIFO in case there is no deferred actions. */
1135         if (action_fifo_is_empty(fifo))
1136                 return;
1137 
1138         /* Finishing executing all deferred actions. */
1139         do {
1140                 struct deferred_action *da = action_fifo_get(fifo);
1141                 struct sk_buff *skb = da->skb;
1142                 struct sw_flow_key *key = &da->pkt_key;
1143                 const struct nlattr *actions = da->actions;
1144 
1145                 if (actions)
1146                         do_execute_actions(dp, skb, key, actions,
1147                                            nla_len(actions));
1148                 else
1149                         ovs_dp_process_packet(skb, key);
1150         } while (!action_fifo_is_empty(fifo));
1151 
1152         /* Reset FIFO for the next packet.  */
1153         action_fifo_init(fifo);
1154 }
1155 
1156 /* Execute a list of actions against 'skb'. */
1157 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
1158                         const struct sw_flow_actions *acts,
1159                         struct sw_flow_key *key)
1160 {
1161         static const int ovs_recursion_limit = 5;
1162         int err, level;
1163 
1164         level = __this_cpu_inc_return(exec_actions_level);
1165         if (unlikely(level > ovs_recursion_limit)) {
1166                 net_crit_ratelimited("ovs: recursion limit reached on datapath %s, probable configuration error\n",
1167                                      ovs_dp_name(dp));
1168                 kfree_skb(skb);
1169                 err = -ENETDOWN;
1170                 goto out;
1171         }
1172 
1173         err = do_execute_actions(dp, skb, key,
1174                                  acts->actions, acts->actions_len);
1175 
1176         if (level == 1)
1177                 process_deferred_actions(dp);
1178 
1179 out:
1180         __this_cpu_dec(exec_actions_level);
1181         return err;
1182 }
1183 
1184 int action_fifos_init(void)
1185 {
1186         action_fifos = alloc_percpu(struct action_fifo);
1187         if (!action_fifos)
1188                 return -ENOMEM;
1189 
1190         return 0;
1191 }
1192 
1193 void action_fifos_exit(void)
1194 {
1195         free_percpu(action_fifos);
1196 }
1197 

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