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 <linux/if_arp.h>
13 #include <net/llc_pdu.h>
15 #include <linux/ipv6.h>
16 #include <linux/kernel.h>
17 #include <linux/tcp.h>
18 #include <linux/udp.h>
20 #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. */
48 int flow_matches(const struct sw_flow_key *a, const struct sw_flow_key *b)
50 return flow_fields_match(a, b, (a->wildcards | b->wildcards));
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. */
59 int flow_del_matches(const struct sw_flow_key *t, const struct sw_flow_key *d, int strict)
61 if (strict && (t->wildcards != d->wildcards))
64 return flow_fields_match(t, d, d->wildcards);
67 void flow_extract_match(struct sw_flow_key* to, const struct ofp_match* from)
69 to->wildcards = ntohs(from->wildcards) & OFPFW_ALL;
70 to->in_port = from->in_port;
71 to->dl_vlan = from->dl_vlan;
72 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
73 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
74 to->dl_type = from->dl_type;
75 to->nw_src = from->nw_src;
76 to->nw_dst = from->nw_dst;
77 to->nw_proto = from->nw_proto;
78 to->tp_src = from->tp_src;
79 to->tp_dst = from->tp_dst;
80 memset(to->pad, '\0', sizeof(to->pad));
83 void flow_fill_match(struct ofp_match* to, const struct sw_flow_key* from)
85 to->wildcards = htons(from->wildcards);
86 to->in_port = from->in_port;
87 to->dl_vlan = from->dl_vlan;
88 memcpy(to->dl_src, from->dl_src, ETH_ALEN);
89 memcpy(to->dl_dst, from->dl_dst, ETH_ALEN);
90 to->dl_type = from->dl_type;
91 to->nw_src = from->nw_src;
92 to->nw_dst = from->nw_dst;
93 to->nw_proto = from->nw_proto;
94 to->tp_src = from->tp_src;
95 to->tp_dst = from->tp_dst;
96 memset(to->pad, '\0', sizeof(to->pad));
99 /* Returns true if 'flow' can be deleted and set up for a deferred free, false
100 * if deletion has already been scheduled (by another thread).
102 * Caller must hold rcu_read_lock. */
103 int flow_del(struct sw_flow *flow)
105 return !atomic_cmpxchg(&flow->deleted, 0, 1);
108 /* Allocates and returns a new flow with 'n_actions' action, using allocation
109 * flags 'flags'. Returns the new flow or a null pointer on failure. */
110 struct sw_flow *flow_alloc(int n_actions, gfp_t flags)
112 struct sw_flow *flow = kmem_cache_alloc(flow_cache, flags);
116 flow->n_actions = n_actions;
117 flow->actions = kmalloc(n_actions * sizeof *flow->actions,
119 if (unlikely(!flow->actions) && n_actions > 0) {
120 kmem_cache_free(flow_cache, flow);
126 /* Frees 'flow' immediately. */
127 void flow_free(struct sw_flow *flow)
131 kfree(flow->actions);
132 kmem_cache_free(flow_cache, flow);
135 /* RCU callback used by flow_deferred_free. */
136 static void rcu_callback(struct rcu_head *rcu)
138 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
142 /* Schedules 'flow' to be freed after the next RCU grace period.
143 * The caller must hold rcu_read_lock for this to be sensible. */
144 void flow_deferred_free(struct sw_flow *flow)
146 call_rcu(&flow->rcu, rcu_callback);
149 /* Prints a representation of 'key' to the kernel log. */
150 void print_flow(const struct sw_flow_key *key)
152 printk("wild%04x port%04x:vlan%04x mac%02x:%02x:%02x:%02x:%02x:%02x"
153 "->%02x:%02x:%02x:%02x:%02x:%02x "
154 "proto%04x ip%u.%u.%u.%u->%u.%u.%u.%u port%d->%d\n",
155 key->wildcards, ntohs(key->in_port), ntohs(key->dl_vlan),
156 key->dl_src[0], key->dl_src[1], key->dl_src[2],
157 key->dl_src[3], key->dl_src[4], key->dl_src[5],
158 key->dl_dst[0], key->dl_dst[1], key->dl_dst[2],
159 key->dl_dst[3], key->dl_dst[4], key->dl_dst[5],
161 ((unsigned char *)&key->nw_src)[0],
162 ((unsigned char *)&key->nw_src)[1],
163 ((unsigned char *)&key->nw_src)[2],
164 ((unsigned char *)&key->nw_src)[3],
165 ((unsigned char *)&key->nw_dst)[0],
166 ((unsigned char *)&key->nw_dst)[1],
167 ((unsigned char *)&key->nw_dst)[2],
168 ((unsigned char *)&key->nw_dst)[3],
169 ntohs(key->tp_src), ntohs(key->tp_dst));
172 uint32_t hash_in6(const struct in6_addr *in)
174 return (in->s6_addr32[0] ^ in->s6_addr32[1]
175 ^ in->s6_addr32[2] ^ in->s6_addr32[3]);
178 // with inspiration from linux/if_arp.h
180 uint16_t ar_hrd; /* format of hardware address */
181 uint16_t ar_pro; /* format of protocol address */
182 uint8_t ar_hln; /* length of hardware address */
183 uint8_t ar_pln; /* length of protocol address */
184 uint16_t ar_op; /* ARP opcode (command) */
186 uint8_t ar_sha[ETH_ALEN]; /* source hardware addr */
187 uint32_t ar_sip; /* source protocol addr */
188 uint8_t ar_tha[ETH_ALEN]; /* dest hardware addr */
189 uint32_t ar_tip; /* dest protocol addr */
190 } __attribute__((packed));
192 /* Parses the Ethernet frame in 'skb', which was received on 'in_port',
193 * and initializes 'key' to match. */
194 void flow_extract(struct sk_buff *skb, uint16_t in_port,
195 struct sw_flow_key *key)
201 key->in_port = htons(in_port);
203 memset(key->pad, '\0', sizeof(key->pad));
205 /* This code doesn't check that skb->len is long enough to contain the
206 * MAC or network header. With a 46-byte minimum length frame this
207 * assumption is always correct. */
209 /* Doesn't verify checksums. Should it? */
211 /* Data link layer. We only support Ethernet. */
213 nh_ofs = sizeof(struct ethhdr);
214 if (likely(ntohs(mac->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF)) {
215 /* This is an Ethernet II frame */
216 key->dl_type = mac->h_proto;
218 /* This is an 802.2 frame */
219 if (snap_get_ethertype(skb, &key->dl_type) != -EINVAL) {
220 nh_ofs += sizeof(struct snap_hdr);
222 key->dl_type = OFP_DL_TYPE_NOT_ETH_TYPE;
223 nh_ofs += sizeof(struct llc_pdu_un);
227 /* Check for a VLAN tag */
228 if (likely(key->dl_type != htons(ETH_P_8021Q))) {
229 key->dl_vlan = htons(OFP_VLAN_NONE);
231 struct vlan_hdr *vh = (struct vlan_hdr *)(skb_mac_header(skb) + nh_ofs);
232 key->dl_type = vh->h_vlan_encapsulated_proto;
233 key->dl_vlan = vh->h_vlan_TCI & htons(VLAN_VID_MASK);
234 nh_ofs += sizeof(*vh);
236 memcpy(key->dl_src, mac->h_source, ETH_ALEN);
237 memcpy(key->dl_dst, mac->h_dest, ETH_ALEN);
238 skb_set_network_header(skb, nh_ofs);
241 if (likely(key->dl_type == htons(ETH_P_IP))) {
242 struct iphdr *nh = ip_hdr(skb);
243 key->nw_src = nh->saddr;
244 key->nw_dst = nh->daddr;
245 key->nw_proto = nh->protocol;
246 th_ofs = nh_ofs + nh->ihl * 4;
247 skb_set_transport_header(skb, th_ofs);
249 /* Transport layer. */
250 if ((key->nw_proto != IPPROTO_TCP && key->nw_proto != IPPROTO_UDP)
251 || skb->len < th_ofs + sizeof(struct udphdr)) {
255 key->tp_src = th->source;
256 key->tp_dst = th->dest;
259 } else if (key->dl_type == htons(ETH_P_IPV6)) {
260 struct ipv6hdr *nh = ipv6_hdr(skb);
261 key->nw_src = hash_in6(&nh->saddr);
262 key->nw_dst = hash_in6(&nh->daddr);
263 /* FIXME: Need to traverse next-headers until we find the
264 * upper-layer header. */
267 } else if (key->dl_type == htons(ETH_P_ARP)) {
268 /* just barely within 46-byte minimum packet */
269 struct arp_eth_hdr *ah = (struct arp_eth_hdr *)skb_network_header(skb);
270 if (ah->ar_hrd == htons(ARPHRD_ETHER)
271 && ah->ar_pro == htons(ETH_P_IP)
272 && ah->ar_hln == ETH_ALEN
273 && ah->ar_pln == sizeof(key->nw_src))
275 /* check if sha/tha match dl_src/dl_dst? */
276 key->nw_src = ah->ar_sip;
277 key->nw_dst = ah->ar_tip;
294 /* Initializes the flow module.
295 * Returns zero if successful or a negative error code. */
298 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
300 if (flow_cache == NULL)
306 /* Uninitializes the flow module. */
309 kmem_cache_destroy(flow_cache);