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/kernel.h>
15 #include <linux/module.h>
16 #include <linux/tcp.h>
17 #include <linux/udp.h>
19 #include <linux/rcupdate.h>
26 struct kmem_cache *flow_cache;
28 /* Internal function used to compare fields in flow. */
30 int flow_fields_match(const struct sw_flow_key *a, const struct sw_flow_key *b,
33 return ((w & OFPFW_IN_PORT || a->in_port == b->in_port)
34 && (w & OFPFW_DL_VLAN || a->dl_vlan == b->dl_vlan)
35 && (w & OFPFW_DL_SRC || !memcmp(a->dl_src, b->dl_src, ETH_ALEN))
36 && (w & OFPFW_DL_DST || !memcmp(a->dl_dst, b->dl_dst, ETH_ALEN))
37 && (w & OFPFW_DL_TYPE || a->dl_type == b->dl_type)
38 && (w & OFPFW_NW_SRC || a->nw_src == b->nw_src)
39 && (w & OFPFW_NW_DST || a->nw_dst == b->nw_dst)
40 && (w & OFPFW_NW_PROTO || a->nw_proto == b->nw_proto)
41 && (w & OFPFW_TP_SRC || a->tp_src == b->tp_src)
42 && (w & OFPFW_TP_DST || a->tp_dst == b->tp_dst));
45 /* Returns nonzero if 'a' and 'b' match, that is, if their fields are equal
46 * modulo wildcards, zero otherwise. */
47 int flow_matches(const struct sw_flow_key *a, const struct sw_flow_key *b)
49 return flow_fields_match(a, b, (a->wildcards | b->wildcards));
51 EXPORT_SYMBOL(flow_matches);
53 /* Returns nonzero if 't' (the table entry's key) and 'd' (the key
54 * describing the deletion) match, that is, if their fields are
55 * equal modulo wildcards, zero otherwise. If 'strict' is nonzero, the
56 * wildcards must match in both 't_key' and 'd_key'. Note that the
57 * table's wildcards are ignored unless 'strict' is set. */
58 int flow_del_matches(const struct sw_flow_key *t, const struct sw_flow_key *d, int strict)
60 if (strict && (t->wildcards != d->wildcards))
63 return flow_fields_match(t, d, d->wildcards);
65 EXPORT_SYMBOL(flow_del_matches);
67 void flow_extract_match(struct sw_flow_key* to, const struct ofp_match* from)
69 to->wildcards = ntohs(from->wildcards) & OFPFW_ALL;
70 memset(to->pad, '\0', sizeof(to->pad));
71 to->in_port = from->in_port;
72 to->dl_vlan = from->dl_vlan;
73 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
74 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
75 to->dl_type = from->dl_type;
77 to->nw_src = to->nw_dst = to->nw_proto = 0;
78 to->tp_src = to->tp_dst = 0;
80 #define OFPFW_TP (OFPFW_TP_SRC | OFPFW_TP_DST)
81 #define OFPFW_NW (OFPFW_NW_SRC | OFPFW_NW_DST | OFPFW_NW_PROTO)
82 if (to->wildcards & OFPFW_DL_TYPE) {
83 /* Can't sensibly match on network or transport headers if the
84 * data link type is unknown. */
85 to->wildcards |= OFPFW_NW | OFPFW_TP;
86 } else if (from->dl_type == htons(ETH_P_IP)) {
87 to->nw_src = from->nw_src;
88 to->nw_dst = from->nw_dst;
89 to->nw_proto = from->nw_proto;
91 if (to->wildcards & OFPFW_NW_PROTO) {
92 /* Can't sensibly match on transport headers if the
93 * network protocol is unknown. */
94 to->wildcards |= OFPFW_TP;
95 } else if (from->nw_proto == IPPROTO_TCP
96 || from->nw_proto == IPPROTO_UDP) {
97 to->tp_src = from->tp_src;
98 to->tp_dst = from->tp_dst;
100 /* Transport layer fields are undefined. Mark them as
101 * exact-match to allow such flows to reside in
102 * table-hash, instead of falling into table-linear. */
103 to->wildcards &= ~OFPFW_TP;
106 /* Network and transport layer fields are undefined. Mark them
107 * as exact-match to allow such flows to reside in table-hash,
108 * instead of falling into table-linear. */
109 to->wildcards &= ~(OFPFW_NW | OFPFW_TP);
113 void flow_fill_match(struct ofp_match* to, const struct sw_flow_key* from)
115 to->wildcards = htons(from->wildcards);
116 to->in_port = from->in_port;
117 to->dl_vlan = from->dl_vlan;
118 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
119 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
120 to->dl_type = from->dl_type;
121 to->nw_src = from->nw_src;
122 to->nw_dst = from->nw_dst;
123 to->nw_proto = from->nw_proto;
124 to->tp_src = from->tp_src;
125 to->tp_dst = from->tp_dst;
126 memset(to->pad, '\0', sizeof(to->pad));
129 /* Allocates and returns a new flow with 'n_actions' action, using allocation
130 * flags 'flags'. Returns the new flow or a null pointer on failure. */
131 struct sw_flow *flow_alloc(int n_actions, gfp_t flags)
133 struct sw_flow *flow = kmem_cache_alloc(flow_cache, flags);
137 flow->n_actions = n_actions;
138 flow->actions = kmalloc(n_actions * sizeof *flow->actions,
140 if (unlikely(!flow->actions) && n_actions > 0) {
141 kmem_cache_free(flow_cache, flow);
147 /* Frees 'flow' immediately. */
148 void flow_free(struct sw_flow *flow)
152 kfree(flow->actions);
153 kmem_cache_free(flow_cache, flow);
155 EXPORT_SYMBOL(flow_free);
157 /* RCU callback used by flow_deferred_free. */
158 static void rcu_callback(struct rcu_head *rcu)
160 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
164 /* Schedules 'flow' to be freed after the next RCU grace period.
165 * The caller must hold rcu_read_lock for this to be sensible. */
166 void flow_deferred_free(struct sw_flow *flow)
168 call_rcu(&flow->rcu, rcu_callback);
170 EXPORT_SYMBOL(flow_deferred_free);
172 /* Prints a representation of 'key' to the kernel log. */
173 void print_flow(const struct sw_flow_key *key)
175 printk("wild%04x port%04x:vlan%04x mac%02x:%02x:%02x:%02x:%02x:%02x"
176 "->%02x:%02x:%02x:%02x:%02x:%02x "
177 "proto%04x ip%u.%u.%u.%u->%u.%u.%u.%u port%d->%d\n",
178 key->wildcards, ntohs(key->in_port), ntohs(key->dl_vlan),
179 key->dl_src[0], key->dl_src[1], key->dl_src[2],
180 key->dl_src[3], key->dl_src[4], key->dl_src[5],
181 key->dl_dst[0], key->dl_dst[1], key->dl_dst[2],
182 key->dl_dst[3], key->dl_dst[4], key->dl_dst[5],
184 ((unsigned char *)&key->nw_src)[0],
185 ((unsigned char *)&key->nw_src)[1],
186 ((unsigned char *)&key->nw_src)[2],
187 ((unsigned char *)&key->nw_src)[3],
188 ((unsigned char *)&key->nw_dst)[0],
189 ((unsigned char *)&key->nw_dst)[1],
190 ((unsigned char *)&key->nw_dst)[2],
191 ((unsigned char *)&key->nw_dst)[3],
192 ntohs(key->tp_src), ntohs(key->tp_dst));
194 EXPORT_SYMBOL(print_flow);
196 static int tcphdr_ok(struct sk_buff *skb)
198 int th_ofs = skb_transport_offset(skb);
199 if (skb->len >= th_ofs + sizeof(struct tcphdr)) {
200 int tcp_len = tcp_hdrlen(skb);
201 return (tcp_len >= sizeof(struct tcphdr)
202 && skb->len >= th_ofs + tcp_len);
207 static int udphdr_ok(struct sk_buff *skb)
209 int th_ofs = skb_transport_offset(skb);
210 return skb->len >= th_ofs + sizeof(struct udphdr);
213 /* Parses the Ethernet frame in 'skb', which was received on 'in_port',
214 * and initializes 'key' to match. */
215 void flow_extract(struct sk_buff *skb, uint16_t in_port,
216 struct sw_flow_key *key)
221 key->in_port = htons(in_port);
223 memset(key->pad, '\0', sizeof(key->pad));
225 /* This code doesn't check that skb->len is long enough to contain the
226 * MAC or network header. With a 46-byte minimum length frame this
227 * assumption is always correct. */
229 /* Doesn't verify checksums. Should it? */
231 /* Data link layer. We only support Ethernet. */
233 nh_ofs = sizeof(struct ethhdr);
234 if (likely(ntohs(mac->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF)) {
235 /* This is an Ethernet II frame */
236 key->dl_type = mac->h_proto;
238 /* This is an 802.2 frame */
239 if (snap_get_ethertype(skb, &key->dl_type) != -EINVAL) {
240 nh_ofs += sizeof(struct snap_hdr);
242 key->dl_type = OFP_DL_TYPE_NOT_ETH_TYPE;
243 nh_ofs += sizeof(struct llc_pdu_un);
247 /* Check for a VLAN tag */
248 if (likely(key->dl_type != htons(ETH_P_8021Q))) {
249 key->dl_vlan = htons(OFP_VLAN_NONE);
251 struct vlan_hdr *vh = (struct vlan_hdr *)(skb_mac_header(skb) + nh_ofs);
252 key->dl_type = vh->h_vlan_encapsulated_proto;
253 key->dl_vlan = vh->h_vlan_TCI & htons(VLAN_VID_MASK);
254 nh_ofs += sizeof(*vh);
256 memcpy(key->dl_src, mac->h_source, ETH_ALEN);
257 memcpy(key->dl_dst, mac->h_dest, ETH_ALEN);
258 skb_set_network_header(skb, nh_ofs);
261 if (likely(key->dl_type == htons(ETH_P_IP))) {
262 struct iphdr *nh = ip_hdr(skb);
263 key->nw_src = nh->saddr;
264 key->nw_dst = nh->daddr;
265 key->nw_proto = nh->protocol;
266 th_ofs = nh_ofs + nh->ihl * 4;
267 skb_set_transport_header(skb, th_ofs);
269 /* Transport layer. */
270 if (!(nh->frag_off & htons(IP_MF | IP_OFFSET))) {
271 if (key->nw_proto == IPPROTO_TCP) {
272 if (tcphdr_ok(skb)) {
273 struct tcphdr *tcp = tcp_hdr(skb);
274 key->tp_src = tcp->source;
275 key->tp_dst = tcp->dest;
277 /* Avoid tricking other code into
278 * thinking that this packet has an L4
282 } else if (key->nw_proto == IPPROTO_UDP) {
283 if (udphdr_ok(skb)) {
284 struct udphdr *udp = udp_hdr(skb);
285 key->tp_src = udp->source;
286 key->tp_dst = udp->dest;
288 /* Avoid tricking other code into
289 * thinking that this packet has an L4
312 /* Initializes the flow module.
313 * Returns zero if successful or a negative error code. */
316 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
318 if (flow_cache == NULL)
324 /* Uninitializes the flow module. */
327 kmem_cache_destroy(flow_cache);