2 * Distributed under the terms of the GNU GPL version 2.
3 * Copyright (c) 2007, 2008, 2009, 2010 Nicira Networks.
5 * Significant portions of this file may be copied from parts of the Linux
6 * kernel, by Linus Torvalds and others.
9 /* Functions for executing flow actions. */
11 #include <linux/skbuff.h>
14 #include <linux/tcp.h>
15 #include <linux/udp.h>
16 #include <linux/in6.h>
17 #include <linux/if_arp.h>
18 #include <linux/if_vlan.h>
19 #include <net/inet_ecn.h>
21 #include <net/checksum.h>
26 #include "openvswitch/datapath-protocol.h"
29 static struct sk_buff *make_writable(struct sk_buff *skb, unsigned min_headroom)
31 if (skb_cloned(skb)) {
33 unsigned headroom = max(min_headroom, skb_headroom(skb));
35 nskb = skb_copy_expand(skb, headroom, skb_tailroom(skb), GFP_ATOMIC);
37 set_skb_csum_bits(skb, nskb);
42 unsigned int hdr_len = (skb_transport_offset(skb)
43 + sizeof(struct tcphdr));
44 if (pskb_may_pull(skb, min(hdr_len, skb->len)))
51 static struct sk_buff *vlan_pull_tag(struct sk_buff *skb)
53 struct vlan_ethhdr *vh = vlan_eth_hdr(skb);
56 /* Verify we were given a vlan packet */
57 if (vh->h_vlan_proto != htons(ETH_P_8021Q) || skb->len < VLAN_ETH_HLEN)
60 if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
61 skb->csum = csum_sub(skb->csum, csum_partial(skb->data
62 + ETH_HLEN, VLAN_HLEN, 0));
64 memmove(skb->data + VLAN_HLEN, skb->data, 2 * VLAN_ETH_ALEN);
66 eh = (struct ethhdr *)skb_pull(skb, VLAN_HLEN);
68 skb->protocol = eh->h_proto;
69 skb->mac_header += VLAN_HLEN;
74 static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
75 const struct odp_flow_key *key,
76 const struct nlattr *a, u32 actions_len)
78 __be16 tci = nla_get_be16(a);
80 skb = make_writable(skb, VLAN_HLEN);
82 return ERR_PTR(-ENOMEM);
84 if (skb->protocol == htons(ETH_P_8021Q)) {
85 /* Modify vlan id, but maintain other TCI values */
86 struct vlan_ethhdr *vh;
89 if (skb->len < VLAN_ETH_HLEN)
92 vh = vlan_eth_hdr(skb);
93 old_tci = vh->h_vlan_TCI;
97 if (get_ip_summed(skb) == OVS_CSUM_COMPLETE) {
98 __be16 diff[] = { ~old_tci, vh->h_vlan_TCI };
100 skb->csum = ~csum_partial((char *)diff, sizeof(diff),
106 /* Add vlan header */
108 /* Set up checksumming pointers for checksum-deferred packets
109 * on Xen. Otherwise, dev_queue_xmit() will try to do this
110 * when we send the packet out on the wire, and it will fail at
111 * that point because skb_checksum_setup() will not look inside
112 * an 802.1Q header. */
113 err = vswitch_skb_checksum_setup(skb);
119 /* GSO is not implemented for packets with an 802.1Q header, so
120 * we have to do segmentation before we add that header.
122 * GSO does work with hardware-accelerated VLAN tagging, but we
123 * can't use hardware-accelerated VLAN tagging since it
124 * requires the device to have a VLAN group configured (with
125 * e.g. vconfig(8)) and we don't do that.
127 * Having to do this here may be a performance loss, since we
128 * can't take advantage of TSO hardware support, although it
129 * does not make a measurable network performance difference
130 * for 1G Ethernet. Fixing that would require patching the
131 * kernel (either to add GSO support to the VLAN protocol or to
132 * support hardware-accelerated VLAN tagging without VLAN
133 * groups configured). */
134 if (skb_is_gso(skb)) {
135 const struct nlattr *actions_left;
136 u32 actions_len_left;
137 struct sk_buff *segs;
139 segs = skb_gso_segment(skb, 0);
142 return ERR_CAST(segs);
144 actions_len_left = actions_len;
145 actions_left = nla_next(a, &actions_len_left);
148 struct sk_buff *nskb = segs->next;
153 /* GSO can change the checksum type so update.*/
154 compute_ip_summed(segs, true);
156 segs = __vlan_put_tag(segs, ntohs(tci));
159 err = execute_actions(
160 dp, segs, key, actions_left,
165 while ((segs = nskb)) {
174 } while (segs->next);
177 compute_ip_summed(skb, true);
180 /* The hardware-accelerated version of vlan_put_tag() works
181 * only for a device that has a VLAN group configured (with
182 * e.g. vconfig(8)), so call the software-only version
183 * __vlan_put_tag() directly instead.
185 skb = __vlan_put_tag(skb, ntohs(tci));
187 return ERR_PTR(-ENOMEM);
189 /* GSO doesn't fix up the hardware computed checksum so this
190 * will only be hit in the non-GSO case. */
191 if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
192 skb->csum = csum_add(skb->csum, csum_partial(skb->data
193 + ETH_HLEN, VLAN_HLEN, 0));
199 static struct sk_buff *strip_vlan(struct sk_buff *skb)
201 skb = make_writable(skb, 0);
207 static bool is_ip(struct sk_buff *skb, const struct odp_flow_key *key)
209 return (key->dl_type == htons(ETH_P_IP) &&
210 skb->transport_header > skb->network_header);
213 static __sum16 *get_l4_checksum(struct sk_buff *skb, const struct odp_flow_key *key)
215 int transport_len = skb->len - skb_transport_offset(skb);
216 if (key->nw_proto == IPPROTO_TCP) {
217 if (likely(transport_len >= sizeof(struct tcphdr)))
218 return &tcp_hdr(skb)->check;
219 } else if (key->nw_proto == IPPROTO_UDP) {
220 if (likely(transport_len >= sizeof(struct udphdr)))
221 return &udp_hdr(skb)->check;
226 static struct sk_buff *set_nw_addr(struct sk_buff *skb,
227 const struct odp_flow_key *key,
228 const struct nlattr *a)
230 __be32 new_nwaddr = nla_get_be32(a);
235 if (unlikely(!is_ip(skb, key)))
238 skb = make_writable(skb, 0);
243 nwaddr = nla_type(a) == ODPAT_SET_NW_SRC ? &nh->saddr : &nh->daddr;
245 check = get_l4_checksum(skb, key);
247 inet_proto_csum_replace4(check, skb, *nwaddr, new_nwaddr, 1);
248 csum_replace4(&nh->check, *nwaddr, new_nwaddr);
250 *nwaddr = new_nwaddr;
255 static struct sk_buff *set_nw_tos(struct sk_buff *skb,
256 const struct odp_flow_key *key,
259 if (unlikely(!is_ip(skb, key)))
262 skb = make_writable(skb, 0);
264 struct iphdr *nh = ip_hdr(skb);
269 /* Set the DSCP bits and preserve the ECN bits. */
270 new = nw_tos | (nh->tos & INET_ECN_MASK);
271 csum_replace4(&nh->check, (__force __be32)old,
272 (__force __be32)new);
278 static struct sk_buff *set_tp_port(struct sk_buff *skb,
279 const struct odp_flow_key *key,
280 const struct nlattr *a)
286 if (unlikely(!is_ip(skb, key)))
289 skb = make_writable(skb, 0);
293 /* Must follow make_writable() since that can move the skb data. */
294 check = get_l4_checksum(skb, key);
295 if (unlikely(!check))
299 * Update port and checksum.
301 * This is OK because source and destination port numbers are at the
302 * same offsets in both UDP and TCP headers, and get_l4_checksum() only
303 * supports those protocols.
306 port = nla_type(a) == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
307 inet_proto_csum_replace2(check, skb, *port, nla_get_be16(a), 0);
308 *port = nla_get_be16(a);
314 * is_spoofed_arp - check for invalid ARP packet
316 * @skb: skbuff containing an Ethernet packet, with network header pointing
317 * just past the Ethernet and optional 802.1Q header.
318 * @key: flow key extracted from @skb by flow_extract()
320 * Returns true if @skb is an invalid Ethernet+IPv4 ARP packet: one with screwy
321 * or truncated header fields or one whose inner and outer Ethernet address
324 static bool is_spoofed_arp(struct sk_buff *skb, const struct odp_flow_key *key)
326 struct arp_eth_header *arp;
328 if (key->dl_type != htons(ETH_P_ARP))
331 if (skb_network_offset(skb) + sizeof(struct arp_eth_header) > skb->len)
334 arp = (struct arp_eth_header *)skb_network_header(skb);
335 return (arp->ar_hrd != htons(ARPHRD_ETHER) ||
336 arp->ar_pro != htons(ETH_P_IP) ||
337 arp->ar_hln != ETH_ALEN ||
339 compare_ether_addr(arp->ar_sha, eth_hdr(skb)->h_source));
342 static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
349 p = rcu_dereference(dp->ports[out_port]);
360 static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg)
362 skb = skb_clone(skb, GFP_ATOMIC);
365 return dp_output_control(dp, skb, _ODPL_ACTION_NR, arg);
368 /* Send a copy of this packet up to the sFlow agent, along with extra
369 * information about what happened to it. */
370 static void sflow_sample(struct datapath *dp, struct sk_buff *skb,
371 const struct nlattr *a, u32 actions_len,
374 struct odp_sflow_sample_header *hdr;
375 unsigned int hdrlen = sizeof(struct odp_sflow_sample_header);
376 struct sk_buff *nskb;
378 nskb = skb_copy_expand(skb, actions_len + hdrlen, 0, GFP_ATOMIC);
382 memcpy(__skb_push(nskb, actions_len), a, actions_len);
383 hdr = (struct odp_sflow_sample_header*)__skb_push(nskb, hdrlen);
384 hdr->actions_len = actions_len;
385 hdr->sample_pool = atomic_read(&vport->sflow_pool);
386 dp_output_control(dp, nskb, _ODPL_SFLOW_NR, 0);
389 /* Execute a list of actions against 'skb'. */
390 int execute_actions(struct datapath *dp, struct sk_buff *skb,
391 const struct odp_flow_key *key,
392 const struct nlattr *actions, u32 actions_len)
394 /* Every output action needs a separate clone of 'skb', but the common
395 * case is just a single output action, so that doing a clone and
396 * then freeing the original skbuff is wasteful. So the following code
397 * is slightly obscure just to avoid that. */
399 u32 priority = skb->priority;
400 const struct nlattr *a;
403 if (dp->sflow_probability) {
404 struct vport *p = OVS_CB(skb)->vport;
406 atomic_inc(&p->sflow_pool);
407 if (dp->sflow_probability == UINT_MAX ||
408 net_random() < dp->sflow_probability)
409 sflow_sample(dp, skb, actions, actions_len, p);
413 OVS_CB(skb)->tun_id = 0;
415 for (a = actions, rem = actions_len; rem > 0; a = nla_next(a, &rem)) {
416 if (prev_port != -1) {
417 do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
421 switch (nla_type(a)) {
423 prev_port = nla_get_u32(a);
426 case ODPAT_CONTROLLER:
427 err = output_control(dp, skb, nla_get_u64(a));
434 case ODPAT_SET_TUNNEL:
435 OVS_CB(skb)->tun_id = nla_get_be64(a);
438 case ODPAT_SET_DL_TCI:
439 skb = modify_vlan_tci(dp, skb, key, a, rem);
444 case ODPAT_STRIP_VLAN:
445 skb = strip_vlan(skb);
448 case ODPAT_SET_DL_SRC:
449 skb = make_writable(skb, 0);
452 memcpy(eth_hdr(skb)->h_source, nla_data(a), ETH_ALEN);
455 case ODPAT_SET_DL_DST:
456 skb = make_writable(skb, 0);
459 memcpy(eth_hdr(skb)->h_dest, nla_data(a), ETH_ALEN);
462 case ODPAT_SET_NW_SRC:
463 case ODPAT_SET_NW_DST:
464 skb = set_nw_addr(skb, key, a);
467 case ODPAT_SET_NW_TOS:
468 skb = set_nw_tos(skb, key, nla_get_u8(a));
471 case ODPAT_SET_TP_SRC:
472 case ODPAT_SET_TP_DST:
473 skb = set_tp_port(skb, key, a);
476 case ODPAT_SET_PRIORITY:
477 skb->priority = nla_get_u32(a);
480 case ODPAT_POP_PRIORITY:
481 skb->priority = priority;
484 case ODPAT_DROP_SPOOFED_ARP:
485 if (unlikely(is_spoofed_arp(skb, key)))
494 do_output(dp, skb, prev_port);