2 * Distributed under the terms of the GNU GPL version 2.
3 * Copyright (c) 2007, 2008 The Board of Trustees of The Leland
4 * Stanford Junior University
8 #include <linux/netdevice.h>
9 #include <linux/etherdevice.h>
10 #include <linux/if_ether.h>
11 #include <linux/if_vlan.h>
12 #include <net/llc_pdu.h>
14 #include <linux/jiffies.h>
15 #include <linux/kernel.h>
16 #include <linux/llc.h>
17 #include <linux/module.h>
18 #include <linux/tcp.h>
19 #include <linux/udp.h>
20 #include <linux/icmp.h>
22 #include <linux/rcupdate.h>
25 #include "openflow/openflow.h"
28 struct kmem_cache *flow_cache;
30 /* Internal function used to compare fields in flow. */
32 int flow_fields_match(const struct sw_flow_key *a, const struct sw_flow_key *b,
33 uint32_t w, uint32_t src_mask, uint32_t dst_mask)
35 return ((w & OFPFW_IN_PORT || a->in_port == b->in_port)
36 && (w & OFPFW_DL_VLAN || a->dl_vlan == b->dl_vlan)
37 && (w & OFPFW_DL_SRC || !memcmp(a->dl_src, b->dl_src, ETH_ALEN))
38 && (w & OFPFW_DL_DST || !memcmp(a->dl_dst, b->dl_dst, ETH_ALEN))
39 && (w & OFPFW_DL_TYPE || a->dl_type == b->dl_type)
40 && !((a->nw_src ^ b->nw_src) & src_mask)
41 && !((a->nw_dst ^ b->nw_dst) & dst_mask)
42 && (w & OFPFW_NW_PROTO || a->nw_proto == b->nw_proto)
43 && (w & OFPFW_TP_SRC || a->tp_src == b->tp_src)
44 && (w & OFPFW_TP_DST || a->tp_dst == b->tp_dst));
47 /* Returns nonzero if 'a' and 'b' match, that is, if their fields are equal
48 * modulo wildcards in 'b', zero otherwise. */
49 int flow_matches_1wild(const struct sw_flow_key *a,
50 const struct sw_flow_key *b)
52 return flow_fields_match(a, b, b->wildcards,
53 b->nw_src_mask, b->nw_dst_mask);
55 EXPORT_SYMBOL(flow_matches_1wild);
57 /* Returns nonzero if 'a' and 'b' match, that is, if their fields are equal
58 * modulo wildcards in 'a' or 'b', zero otherwise. */
59 int flow_matches_2wild(const struct sw_flow_key *a,
60 const struct sw_flow_key *b)
62 return flow_fields_match(a, b,
63 a->wildcards | b->wildcards,
64 a->nw_src_mask & b->nw_src_mask,
65 a->nw_dst_mask & b->nw_dst_mask);
67 EXPORT_SYMBOL(flow_matches_2wild);
69 /* Returns nonzero if 't' (the table entry's key) and 'd' (the key
70 * describing the match) match, that is, if their fields are
71 * equal modulo wildcards, zero otherwise. If 'strict' is nonzero, the
72 * wildcards must match in both 't_key' and 'd_key'. Note that the
73 * table's wildcards are ignored unless 'strict' is set. */
74 int flow_matches_desc(const struct sw_flow_key *t, const struct sw_flow_key *d,
77 if (strict && d->wildcards != t->wildcards)
79 return flow_matches_1wild(t, d);
81 EXPORT_SYMBOL(flow_matches_desc);
83 static uint32_t make_nw_mask(int n_wild_bits)
85 n_wild_bits &= (1u << OFPFW_NW_SRC_BITS) - 1;
86 return n_wild_bits < 32 ? htonl(~((1u << n_wild_bits) - 1)) : 0;
89 void flow_extract_match(struct sw_flow_key* to, const struct ofp_match* from)
91 to->wildcards = ntohl(from->wildcards) & OFPFW_ALL;
93 to->in_port = from->in_port;
94 to->dl_vlan = from->dl_vlan;
95 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
96 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
97 to->dl_type = from->dl_type;
99 to->nw_src = to->nw_dst = to->nw_proto = 0;
100 to->tp_src = to->tp_dst = 0;
102 #define OFPFW_TP (OFPFW_TP_SRC | OFPFW_TP_DST)
103 #define OFPFW_NW (OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK | OFPFW_NW_PROTO)
104 if (to->wildcards & OFPFW_DL_TYPE) {
105 /* Can't sensibly match on network or transport headers if the
106 * data link type is unknown. */
107 to->wildcards |= OFPFW_NW | OFPFW_TP;
108 } else if (from->dl_type == htons(ETH_P_IP)) {
109 to->nw_src = from->nw_src;
110 to->nw_dst = from->nw_dst;
111 to->nw_proto = from->nw_proto;
113 if (to->wildcards & OFPFW_NW_PROTO) {
114 /* Can't sensibly match on transport headers if the
115 * network protocol is unknown. */
116 to->wildcards |= OFPFW_TP;
117 } else if (from->nw_proto == IPPROTO_TCP
118 || from->nw_proto == IPPROTO_UDP
119 || from->nw_proto == IPPROTO_ICMP) {
120 to->tp_src = from->tp_src;
121 to->tp_dst = from->tp_dst;
123 /* Transport layer fields are undefined. Mark them as
124 * exact-match to allow such flows to reside in
125 * table-hash, instead of falling into table-linear. */
126 to->wildcards &= ~OFPFW_TP;
129 /* Network and transport layer fields are undefined. Mark them
130 * as exact-match to allow such flows to reside in table-hash,
131 * instead of falling into table-linear. */
132 to->wildcards &= ~(OFPFW_NW | OFPFW_TP);
135 /* We set these late because code above adjusts to->wildcards. */
136 to->nw_src_mask = make_nw_mask(to->wildcards >> OFPFW_NW_SRC_SHIFT);
137 to->nw_dst_mask = make_nw_mask(to->wildcards >> OFPFW_NW_DST_SHIFT);
140 void flow_fill_match(struct ofp_match* to, const struct sw_flow_key* from)
142 to->wildcards = htonl(from->wildcards);
143 to->in_port = from->in_port;
144 to->dl_vlan = from->dl_vlan;
145 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
146 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
147 to->dl_type = from->dl_type;
148 to->nw_src = from->nw_src;
149 to->nw_dst = from->nw_dst;
150 to->nw_proto = from->nw_proto;
151 to->tp_src = from->tp_src;
152 to->tp_dst = from->tp_dst;
156 int flow_timeout(struct sw_flow *flow)
158 if (flow->idle_timeout != OFP_FLOW_PERMANENT
159 && time_after(jiffies, flow->used + flow->idle_timeout * HZ))
160 return OFPER_IDLE_TIMEOUT;
161 else if (flow->hard_timeout != OFP_FLOW_PERMANENT
162 && time_after(jiffies,
163 flow->init_time + flow->hard_timeout * HZ))
164 return OFPER_HARD_TIMEOUT;
168 EXPORT_SYMBOL(flow_timeout);
170 /* Returns nonzero if 'flow' contains an output action to 'out_port' or
171 * has the value OFPP_NONE. 'out_port' is in network-byte order. */
172 int flow_has_out_port(struct sw_flow *flow, uint16_t out_port)
174 struct sw_flow_actions *sf_acts;
178 if (out_port == htons(OFPP_NONE))
181 sf_acts = rcu_dereference(flow->sf_acts);
183 actions_len = sf_acts->actions_len;
184 p = (uint8_t *)sf_acts->actions;
186 while (actions_len > 0) {
187 struct ofp_action_header *ah = (struct ofp_action_header *)p;
188 size_t len = ntohs(ah->len);
190 if (ah->type == htons(OFPAT_OUTPUT)) {
191 struct ofp_action_output *oa = (struct ofp_action_output *)p;
192 if (oa->port == out_port)
202 EXPORT_SYMBOL(flow_has_out_port);
204 /* Allocates and returns a new flow with room for 'actions_len' actions,
205 * using allocation flags 'flags'. Returns the new flow or a null pointer
207 struct sw_flow *flow_alloc(size_t actions_len, gfp_t flags)
209 struct sw_flow_actions *sfa;
210 size_t size = sizeof *sfa + actions_len;
211 struct sw_flow *flow = kmem_cache_alloc(flow_cache, flags);
215 sfa = kmalloc(size, flags);
216 if (unlikely(!sfa)) {
217 kmem_cache_free(flow_cache, flow);
220 sfa->actions_len = actions_len;
226 /* Frees 'flow' immediately. */
227 void flow_free(struct sw_flow *flow)
231 kfree(flow->sf_acts);
232 kmem_cache_free(flow_cache, flow);
234 EXPORT_SYMBOL(flow_free);
236 /* RCU callback used by flow_deferred_free. */
237 static void rcu_free_flow_callback(struct rcu_head *rcu)
239 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
243 /* Schedules 'flow' to be freed after the next RCU grace period.
244 * The caller must hold rcu_read_lock for this to be sensible. */
245 void flow_deferred_free(struct sw_flow *flow)
247 call_rcu(&flow->rcu, rcu_free_flow_callback);
249 EXPORT_SYMBOL(flow_deferred_free);
251 /* RCU callback used by flow_deferred_free_acts. */
252 static void rcu_free_acts_callback(struct rcu_head *rcu)
254 struct sw_flow_actions *sf_acts = container_of(rcu,
255 struct sw_flow_actions, rcu);
259 /* Schedules 'sf_acts' to be freed after the next RCU grace period.
260 * The caller must hold rcu_read_lock for this to be sensible. */
261 void flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
263 call_rcu(&sf_acts->rcu, rcu_free_acts_callback);
265 EXPORT_SYMBOL(flow_deferred_free_acts);
267 /* Copies 'actions' into a newly allocated structure for use by 'flow'
268 * and safely frees the structure that defined the previous actions. */
269 void flow_replace_acts(struct sw_flow *flow,
270 const struct ofp_action_header *actions, size_t actions_len)
272 struct sw_flow_actions *sfa;
273 struct sw_flow_actions *orig_sfa = flow->sf_acts;
274 size_t size = sizeof *sfa + actions_len;
276 sfa = kmalloc(size, GFP_ATOMIC);
280 sfa->actions_len = actions_len;
281 memcpy(sfa->actions, actions, actions_len);
283 rcu_assign_pointer(flow->sf_acts, sfa);
284 flow_deferred_free_acts(orig_sfa);
288 EXPORT_SYMBOL(flow_replace_acts);
290 /* Prints a representation of 'key' to the kernel log. */
291 void print_flow(const struct sw_flow_key *key)
293 printk("wild%08x port%04x:vlan%04x mac%02x:%02x:%02x:%02x:%02x:%02x"
294 "->%02x:%02x:%02x:%02x:%02x:%02x "
295 "proto%04x ip%u.%u.%u.%u->%u.%u.%u.%u port%d->%d\n",
296 key->wildcards, ntohs(key->in_port), ntohs(key->dl_vlan),
297 key->dl_src[0], key->dl_src[1], key->dl_src[2],
298 key->dl_src[3], key->dl_src[4], key->dl_src[5],
299 key->dl_dst[0], key->dl_dst[1], key->dl_dst[2],
300 key->dl_dst[3], key->dl_dst[4], key->dl_dst[5],
302 ((unsigned char *)&key->nw_src)[0],
303 ((unsigned char *)&key->nw_src)[1],
304 ((unsigned char *)&key->nw_src)[2],
305 ((unsigned char *)&key->nw_src)[3],
306 ((unsigned char *)&key->nw_dst)[0],
307 ((unsigned char *)&key->nw_dst)[1],
308 ((unsigned char *)&key->nw_dst)[2],
309 ((unsigned char *)&key->nw_dst)[3],
310 ntohs(key->tp_src), ntohs(key->tp_dst));
312 EXPORT_SYMBOL(print_flow);
314 #define SNAP_OUI_LEN 3
319 uint8_t dsap; /* Always 0xAA */
320 uint8_t ssap; /* Always 0xAA */
322 uint8_t oui[SNAP_OUI_LEN];
324 } __attribute__ ((packed));
326 static int is_snap(const struct eth_snap_hdr *esh)
328 return (esh->dsap == LLC_SAP_SNAP
329 && esh->ssap == LLC_SAP_SNAP
330 && !memcmp(esh->oui, "\0\0\0", 3));
333 static int iphdr_ok(struct sk_buff *skb)
335 int nh_ofs = skb_network_offset(skb);
336 if (skb->len >= nh_ofs + sizeof(struct iphdr)) {
337 int ip_len = ip_hdrlen(skb);
338 return (ip_len >= sizeof(struct iphdr)
339 && pskb_may_pull(skb, nh_ofs + ip_len));
344 static int tcphdr_ok(struct sk_buff *skb)
346 int th_ofs = skb_transport_offset(skb);
347 if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) {
348 int tcp_len = tcp_hdrlen(skb);
349 return (tcp_len >= sizeof(struct tcphdr)
350 && skb->len >= th_ofs + tcp_len);
355 static int udphdr_ok(struct sk_buff *skb)
357 int th_ofs = skb_transport_offset(skb);
358 return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr));
361 static int icmphdr_ok(struct sk_buff *skb)
363 int th_ofs = skb_transport_offset(skb);
364 return pskb_may_pull(skb, th_ofs + sizeof(struct icmphdr));
367 /* Parses the Ethernet frame in 'skb', which was received on 'in_port',
368 * and initializes 'key' to match. Returns 1 if 'skb' contains an IP
369 * fragment, 0 otherwise. */
370 int flow_extract(struct sk_buff *skb, uint16_t in_port,
371 struct sw_flow_key *key)
374 struct eth_snap_hdr *esh;
378 memset(key, 0, sizeof *key);
379 key->dl_vlan = htons(OFP_VLAN_NONE);
380 key->in_port = htons(in_port);
382 if (skb->len < sizeof *eth)
384 if (!pskb_may_pull(skb, skb->len >= 64 ? 64 : skb->len)) {
388 skb_reset_mac_header(skb);
390 esh = (struct eth_snap_hdr *) eth;
391 nh_ofs = sizeof *eth;
392 if (likely(ntohs(eth->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF))
393 key->dl_type = eth->h_proto;
394 else if (skb->len >= sizeof *esh && is_snap(esh)) {
395 key->dl_type = esh->ethertype;
396 nh_ofs = sizeof *esh;
398 key->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
399 if (skb->len >= nh_ofs + sizeof(struct llc_pdu_un)) {
400 nh_ofs += sizeof(struct llc_pdu_un);
404 /* Check for a VLAN tag */
405 if (key->dl_type == htons(ETH_P_8021Q) &&
406 skb->len >= nh_ofs + sizeof(struct vlan_hdr)) {
407 struct vlan_hdr *vh = (struct vlan_hdr*)(skb->data + nh_ofs);
408 key->dl_type = vh->h_vlan_encapsulated_proto;
409 key->dl_vlan = vh->h_vlan_TCI & htons(VLAN_VID_MASK);
410 nh_ofs += sizeof(struct vlan_hdr);
412 memcpy(key->dl_src, eth->h_source, ETH_ALEN);
413 memcpy(key->dl_dst, eth->h_dest, ETH_ALEN);
414 skb_set_network_header(skb, nh_ofs);
417 if (key->dl_type == htons(ETH_P_IP) && iphdr_ok(skb)) {
418 struct iphdr *nh = ip_hdr(skb);
419 int th_ofs = nh_ofs + nh->ihl * 4;
420 key->nw_src = nh->saddr;
421 key->nw_dst = nh->daddr;
422 key->nw_proto = nh->protocol;
423 skb_set_transport_header(skb, th_ofs);
425 /* Transport layer. */
426 if (!(nh->frag_off & htons(IP_MF | IP_OFFSET))) {
427 if (key->nw_proto == IPPROTO_TCP) {
428 if (tcphdr_ok(skb)) {
429 struct tcphdr *tcp = tcp_hdr(skb);
430 key->tp_src = tcp->source;
431 key->tp_dst = tcp->dest;
433 /* Avoid tricking other code into
434 * thinking that this packet has an L4
438 } else if (key->nw_proto == IPPROTO_UDP) {
439 if (udphdr_ok(skb)) {
440 struct udphdr *udp = udp_hdr(skb);
441 key->tp_src = udp->source;
442 key->tp_dst = udp->dest;
444 /* Avoid tricking other code into
445 * thinking that this packet has an L4
449 } else if (key->nw_proto == IPPROTO_ICMP) {
450 if (icmphdr_ok(skb)) {
451 struct icmphdr *icmp = icmp_hdr(skb);
452 /* The ICMP type and code fields use the 16-bit
453 * transport port fields, so we need to store them
454 * in 16-bit network byte order. */
455 key->icmp_type = htons(icmp->type);
456 key->icmp_code = htons(icmp->code);
458 /* Avoid tricking other code into
459 * thinking that this packet has an L4
468 skb_reset_transport_header(skb);
473 /* Initializes the flow module.
474 * Returns zero if successful or a negative error code. */
477 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
479 if (flow_cache == NULL)
485 /* Uninitializes the flow module. */
488 kmem_cache_destroy(flow_cache);