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/module.h>
17 #include <linux/tcp.h>
18 #include <linux/udp.h>
20 #include <linux/rcupdate.h>
27 struct kmem_cache *flow_cache;
29 /* Internal function used to compare fields in flow. */
31 int flow_fields_match(const struct sw_flow_key *a, const struct sw_flow_key *b,
32 uint32_t w, uint32_t src_mask, uint32_t dst_mask)
34 return ((w & OFPFW_IN_PORT || a->in_port == b->in_port)
35 && (w & OFPFW_DL_VLAN || a->dl_vlan == b->dl_vlan)
36 && (w & OFPFW_DL_SRC || !memcmp(a->dl_src, b->dl_src, ETH_ALEN))
37 && (w & OFPFW_DL_DST || !memcmp(a->dl_dst, b->dl_dst, ETH_ALEN))
38 && (w & OFPFW_DL_TYPE || a->dl_type == b->dl_type)
39 && !((a->nw_src ^ b->nw_src) & src_mask)
40 && !((a->nw_dst ^ b->nw_dst) & dst_mask)
41 && (w & OFPFW_NW_PROTO || a->nw_proto == b->nw_proto)
42 && (w & OFPFW_TP_SRC || a->tp_src == b->tp_src)
43 && (w & OFPFW_TP_DST || a->tp_dst == b->tp_dst));
46 /* Returns nonzero if 'a' and 'b' match, that is, if their fields are equal
47 * modulo wildcards in 'b', zero otherwise. */
48 int flow_matches_1wild(const struct sw_flow_key *a,
49 const struct sw_flow_key *b)
51 return flow_fields_match(a, b, b->wildcards,
52 b->nw_src_mask, b->nw_dst_mask);
54 EXPORT_SYMBOL(flow_matches_1wild);
56 /* Returns nonzero if 'a' and 'b' match, that is, if their fields are equal
57 * modulo wildcards in 'a' or 'b', zero otherwise. */
58 int flow_matches_2wild(const struct sw_flow_key *a,
59 const struct sw_flow_key *b)
61 return flow_fields_match(a, b,
62 a->wildcards | b->wildcards,
63 a->nw_src_mask & b->nw_src_mask,
64 a->nw_dst_mask & b->nw_dst_mask);
66 EXPORT_SYMBOL(flow_matches_2wild);
68 /* Returns nonzero if 't' (the table entry's key) and 'd' (the key
69 * describing the deletion) match, that is, if their fields are
70 * equal modulo wildcards, zero otherwise. If 'strict' is nonzero, the
71 * wildcards must match in both 't_key' and 'd_key'. Note that the
72 * table's wildcards are ignored unless 'strict' is set. */
73 int flow_del_matches(const struct sw_flow_key *t, const struct sw_flow_key *d, int strict)
75 if (strict && d->wildcards != t->wildcards)
77 return flow_matches_1wild(t, d);
79 EXPORT_SYMBOL(flow_del_matches);
81 static uint32_t make_nw_mask(int n_wild_bits)
83 n_wild_bits &= (1u << OFPFW_NW_SRC_BITS) - 1;
84 return n_wild_bits < 32 ? htonl(~((1u << n_wild_bits) - 1)) : 0;
87 void flow_extract_match(struct sw_flow_key* to, const struct ofp_match* from)
89 to->wildcards = ntohl(from->wildcards) & OFPFW_ALL;
91 to->in_port = from->in_port;
92 to->dl_vlan = from->dl_vlan;
93 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
94 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
95 to->dl_type = from->dl_type;
97 to->nw_src = to->nw_dst = to->nw_proto = 0;
98 to->tp_src = to->tp_dst = 0;
100 #define OFPFW_TP (OFPFW_TP_SRC | OFPFW_TP_DST)
101 #define OFPFW_NW (OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK | OFPFW_NW_PROTO)
102 if (to->wildcards & OFPFW_DL_TYPE) {
103 /* Can't sensibly match on network or transport headers if the
104 * data link type is unknown. */
105 to->wildcards |= OFPFW_NW | OFPFW_TP;
106 } else if (from->dl_type == htons(ETH_P_IP)) {
107 to->nw_src = from->nw_src;
108 to->nw_dst = from->nw_dst;
109 to->nw_proto = from->nw_proto;
111 if (to->wildcards & OFPFW_NW_PROTO) {
112 /* Can't sensibly match on transport headers if the
113 * network protocol is unknown. */
114 to->wildcards |= OFPFW_TP;
115 } else if (from->nw_proto == IPPROTO_TCP
116 || from->nw_proto == IPPROTO_UDP) {
117 to->tp_src = from->tp_src;
118 to->tp_dst = from->tp_dst;
120 /* Transport layer fields are undefined. Mark them as
121 * exact-match to allow such flows to reside in
122 * table-hash, instead of falling into table-linear. */
123 to->wildcards &= ~OFPFW_TP;
126 /* Network and transport layer fields are undefined. Mark them
127 * as exact-match to allow such flows to reside in table-hash,
128 * instead of falling into table-linear. */
129 to->wildcards &= ~(OFPFW_NW | OFPFW_TP);
132 /* We set these late because code above adjusts to->wildcards. */
133 to->nw_src_mask = make_nw_mask(to->wildcards >> OFPFW_NW_SRC_SHIFT);
134 to->nw_dst_mask = make_nw_mask(to->wildcards >> OFPFW_NW_DST_SHIFT);
137 void flow_fill_match(struct ofp_match* to, const struct sw_flow_key* from)
139 to->wildcards = htonl(from->wildcards);
140 to->in_port = from->in_port;
141 to->dl_vlan = from->dl_vlan;
142 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
143 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
144 to->dl_type = from->dl_type;
145 to->nw_src = from->nw_src;
146 to->nw_dst = from->nw_dst;
147 to->nw_proto = from->nw_proto;
148 to->tp_src = from->tp_src;
149 to->tp_dst = from->tp_dst;
153 int flow_timeout(struct sw_flow *flow)
155 if (flow->idle_timeout != OFP_FLOW_PERMANENT
156 && time_after(jiffies, flow->used + flow->idle_timeout * HZ))
157 return OFPER_IDLE_TIMEOUT;
158 else if (flow->hard_timeout != OFP_FLOW_PERMANENT
159 && time_after(jiffies,
160 flow->init_time + flow->hard_timeout * HZ))
161 return OFPER_HARD_TIMEOUT;
165 EXPORT_SYMBOL(flow_timeout);
167 /* Allocates and returns a new flow with 'n_actions' action, using allocation
168 * flags 'flags'. Returns the new flow or a null pointer on failure. */
169 struct sw_flow *flow_alloc(int n_actions, gfp_t flags)
171 struct sw_flow *flow = kmem_cache_alloc(flow_cache, flags);
175 flow->n_actions = n_actions;
176 flow->actions = kmalloc(n_actions * sizeof *flow->actions,
178 if (unlikely(!flow->actions) && n_actions > 0) {
179 kmem_cache_free(flow_cache, flow);
185 /* Frees 'flow' immediately. */
186 void flow_free(struct sw_flow *flow)
190 kfree(flow->actions);
191 kmem_cache_free(flow_cache, flow);
193 EXPORT_SYMBOL(flow_free);
195 /* RCU callback used by flow_deferred_free. */
196 static void rcu_callback(struct rcu_head *rcu)
198 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
202 /* Schedules 'flow' to be freed after the next RCU grace period.
203 * The caller must hold rcu_read_lock for this to be sensible. */
204 void flow_deferred_free(struct sw_flow *flow)
206 call_rcu(&flow->rcu, rcu_callback);
208 EXPORT_SYMBOL(flow_deferred_free);
210 /* Prints a representation of 'key' to the kernel log. */
211 void print_flow(const struct sw_flow_key *key)
213 printk("wild%08x port%04x:vlan%04x mac%02x:%02x:%02x:%02x:%02x:%02x"
214 "->%02x:%02x:%02x:%02x:%02x:%02x "
215 "proto%04x ip%u.%u.%u.%u->%u.%u.%u.%u port%d->%d\n",
216 key->wildcards, ntohs(key->in_port), ntohs(key->dl_vlan),
217 key->dl_src[0], key->dl_src[1], key->dl_src[2],
218 key->dl_src[3], key->dl_src[4], key->dl_src[5],
219 key->dl_dst[0], key->dl_dst[1], key->dl_dst[2],
220 key->dl_dst[3], key->dl_dst[4], key->dl_dst[5],
222 ((unsigned char *)&key->nw_src)[0],
223 ((unsigned char *)&key->nw_src)[1],
224 ((unsigned char *)&key->nw_src)[2],
225 ((unsigned char *)&key->nw_src)[3],
226 ((unsigned char *)&key->nw_dst)[0],
227 ((unsigned char *)&key->nw_dst)[1],
228 ((unsigned char *)&key->nw_dst)[2],
229 ((unsigned char *)&key->nw_dst)[3],
230 ntohs(key->tp_src), ntohs(key->tp_dst));
232 EXPORT_SYMBOL(print_flow);
234 static int tcphdr_ok(struct sk_buff *skb)
236 int th_ofs = skb_transport_offset(skb);
237 if (skb->len >= th_ofs + sizeof(struct tcphdr)) {
238 int tcp_len = tcp_hdrlen(skb);
239 return (tcp_len >= sizeof(struct tcphdr)
240 && skb->len >= th_ofs + tcp_len);
245 static int udphdr_ok(struct sk_buff *skb)
247 int th_ofs = skb_transport_offset(skb);
248 return skb->len >= th_ofs + sizeof(struct udphdr);
251 /* Parses the Ethernet frame in 'skb', which was received on 'in_port',
252 * and initializes 'key' to match. Returns 1 if 'skb' contains an IP
253 * fragment, 0 otherwise. */
254 int flow_extract(struct sk_buff *skb, uint16_t in_port,
255 struct sw_flow_key *key)
261 key->in_port = htons(in_port);
264 key->nw_src_mask = 0;
265 key->nw_dst_mask = 0;
267 /* This code doesn't check that skb->len is long enough to contain the
268 * MAC or network header. With a 46-byte minimum length frame this
269 * assumption is always correct. */
271 /* Doesn't verify checksums. Should it? */
273 /* Data link layer. We only support Ethernet. */
275 nh_ofs = sizeof(struct ethhdr);
276 if (likely(ntohs(mac->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF)) {
277 /* This is an Ethernet II frame */
278 key->dl_type = mac->h_proto;
280 /* This is an 802.2 frame */
281 if (snap_get_ethertype(skb, &key->dl_type) != -EINVAL) {
282 nh_ofs += sizeof(struct snap_hdr);
284 key->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
285 nh_ofs += sizeof(struct llc_pdu_un);
289 /* Check for a VLAN tag */
290 if (likely(key->dl_type != htons(ETH_P_8021Q))) {
291 key->dl_vlan = htons(OFP_VLAN_NONE);
293 struct vlan_hdr *vh = (struct vlan_hdr *)(skb_mac_header(skb) + nh_ofs);
294 key->dl_type = vh->h_vlan_encapsulated_proto;
295 key->dl_vlan = vh->h_vlan_TCI & htons(VLAN_VID_MASK);
296 nh_ofs += sizeof(*vh);
298 memcpy(key->dl_src, mac->h_source, ETH_ALEN);
299 memcpy(key->dl_dst, mac->h_dest, ETH_ALEN);
300 skb_set_network_header(skb, nh_ofs);
303 if (likely(key->dl_type == htons(ETH_P_IP))) {
304 struct iphdr *nh = ip_hdr(skb);
305 key->nw_src = nh->saddr;
306 key->nw_dst = nh->daddr;
307 key->nw_proto = nh->protocol;
308 th_ofs = nh_ofs + nh->ihl * 4;
309 skb_set_transport_header(skb, th_ofs);
311 /* Transport layer. */
312 if (!(nh->frag_off & htons(IP_MF | IP_OFFSET))) {
313 if (key->nw_proto == IPPROTO_TCP) {
314 if (tcphdr_ok(skb)) {
315 struct tcphdr *tcp = tcp_hdr(skb);
316 key->tp_src = tcp->source;
317 key->tp_dst = tcp->dest;
319 /* Avoid tricking other code into
320 * thinking that this packet has an L4
324 } else if (key->nw_proto == IPPROTO_UDP) {
325 if (udphdr_ok(skb)) {
326 struct udphdr *udp = udp_hdr(skb);
327 key->tp_src = udp->source;
328 key->tp_dst = udp->dest;
330 /* Avoid tricking other code into
331 * thinking that this packet has an L4
358 /* Initializes the flow module.
359 * Returns zero if successful or a negative error code. */
362 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
364 if (flow_cache == NULL)
370 /* Uninitializes the flow module. */
373 kmem_cache_destroy(flow_cache);