mirror of
https://github.com/openvswitch/ovs
synced 2025-08-28 21:07:47 +00:00
510 lines
16 KiB
C
510 lines
16 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include "flow.h"
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#include <inttypes.h>
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#include <netinet/in.h>
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#include <stdlib.h>
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#include <string.h>
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#include "byte-order.h"
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#include "coverage.h"
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#include "dynamic-string.h"
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#include "hash.h"
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#include "ofpbuf.h"
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#include "openflow/openflow.h"
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#include "openvswitch/datapath-protocol.h"
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#include "packets.h"
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#include "unaligned.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(flow);
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static struct arp_eth_header *
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pull_arp(struct ofpbuf *packet)
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{
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return ofpbuf_try_pull(packet, ARP_ETH_HEADER_LEN);
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}
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static struct ip_header *
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pull_ip(struct ofpbuf *packet)
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{
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if (packet->size >= IP_HEADER_LEN) {
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struct ip_header *ip = packet->data;
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int ip_len = IP_IHL(ip->ip_ihl_ver) * 4;
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if (ip_len >= IP_HEADER_LEN && packet->size >= ip_len) {
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return ofpbuf_pull(packet, ip_len);
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}
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}
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return NULL;
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}
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static struct tcp_header *
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pull_tcp(struct ofpbuf *packet)
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{
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if (packet->size >= TCP_HEADER_LEN) {
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struct tcp_header *tcp = packet->data;
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int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
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if (tcp_len >= TCP_HEADER_LEN && packet->size >= tcp_len) {
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return ofpbuf_pull(packet, tcp_len);
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}
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}
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return NULL;
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}
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static struct udp_header *
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pull_udp(struct ofpbuf *packet)
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{
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return ofpbuf_try_pull(packet, UDP_HEADER_LEN);
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}
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static struct icmp_header *
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pull_icmp(struct ofpbuf *packet)
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{
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return ofpbuf_try_pull(packet, ICMP_HEADER_LEN);
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}
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static void
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parse_vlan(struct ofpbuf *b, struct flow *flow)
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{
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struct qtag_prefix {
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ovs_be16 eth_type; /* ETH_TYPE_VLAN */
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ovs_be16 tci;
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};
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if (b->size >= sizeof(struct qtag_prefix) + sizeof(ovs_be16)) {
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struct qtag_prefix *qp = ofpbuf_pull(b, sizeof *qp);
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flow->dl_vlan = qp->tci & htons(VLAN_VID_MASK);
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flow->dl_vlan_pcp = vlan_tci_to_pcp(qp->tci);
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}
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}
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static ovs_be16
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parse_ethertype(struct ofpbuf *b)
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{
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struct llc_snap_header *llc;
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ovs_be16 proto;
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proto = *(ovs_be16 *) ofpbuf_pull(b, sizeof proto);
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if (ntohs(proto) >= ODP_DL_TYPE_ETH2_CUTOFF) {
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return proto;
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}
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if (b->size < sizeof *llc) {
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return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
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}
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llc = b->data;
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if (llc->llc.llc_dsap != LLC_DSAP_SNAP
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|| llc->llc.llc_ssap != LLC_SSAP_SNAP
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|| llc->llc.llc_cntl != LLC_CNTL_SNAP
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|| memcmp(llc->snap.snap_org, SNAP_ORG_ETHERNET,
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sizeof llc->snap.snap_org)) {
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return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
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}
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ofpbuf_pull(b, sizeof *llc);
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return llc->snap.snap_type;
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}
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/* Initializes 'flow' members from 'packet', 'tun_id', and 'in_port.
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* Initializes 'packet' header pointers as follows:
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*
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* - packet->l2 to the start of the Ethernet header.
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*
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* - packet->l3 to just past the Ethernet header, or just past the
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* vlan_header if one is present, to the first byte of the payload of the
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* Ethernet frame.
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*
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* - packet->l4 to just past the IPv4 header, if one is present and has a
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* correct length, and otherwise NULL.
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*
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* - packet->l7 to just past the TCP or UDP or ICMP header, if one is
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* present and has a correct length, and otherwise NULL.
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*/
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int
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flow_extract(struct ofpbuf *packet, ovs_be32 tun_id, uint16_t in_port,
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struct flow *flow)
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{
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struct ofpbuf b = *packet;
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struct eth_header *eth;
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int retval = 0;
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COVERAGE_INC(flow_extract);
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memset(flow, 0, sizeof *flow);
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flow->tun_id = tun_id;
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flow->in_port = in_port;
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flow->dl_vlan = htons(OFP_VLAN_NONE);
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packet->l2 = b.data;
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packet->l3 = NULL;
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packet->l4 = NULL;
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packet->l7 = NULL;
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if (b.size < sizeof *eth) {
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return 0;
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}
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/* Link layer. */
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eth = b.data;
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memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
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memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
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/* dl_type, dl_vlan, dl_vlan_pcp. */
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ofpbuf_pull(&b, ETH_ADDR_LEN * 2);
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if (eth->eth_type == htons(ETH_TYPE_VLAN)) {
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parse_vlan(&b, flow);
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}
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flow->dl_type = parse_ethertype(&b);
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/* Network layer. */
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packet->l3 = b.data;
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if (flow->dl_type == htons(ETH_TYPE_IP)) {
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const struct ip_header *nh = pull_ip(&b);
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if (nh) {
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flow->nw_src = get_unaligned_u32(&nh->ip_src);
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flow->nw_dst = get_unaligned_u32(&nh->ip_dst);
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flow->nw_tos = nh->ip_tos & IP_DSCP_MASK;
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flow->nw_proto = nh->ip_proto;
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packet->l4 = b.data;
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if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
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if (flow->nw_proto == IP_TYPE_TCP) {
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const struct tcp_header *tcp = pull_tcp(&b);
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if (tcp) {
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flow->tp_src = tcp->tcp_src;
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flow->tp_dst = tcp->tcp_dst;
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packet->l7 = b.data;
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}
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} else if (flow->nw_proto == IP_TYPE_UDP) {
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const struct udp_header *udp = pull_udp(&b);
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if (udp) {
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flow->tp_src = udp->udp_src;
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flow->tp_dst = udp->udp_dst;
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packet->l7 = b.data;
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}
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} else if (flow->nw_proto == IP_TYPE_ICMP) {
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const struct icmp_header *icmp = pull_icmp(&b);
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if (icmp) {
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flow->icmp_type = htons(icmp->icmp_type);
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flow->icmp_code = htons(icmp->icmp_code);
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packet->l7 = b.data;
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}
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}
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} else {
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retval = 1;
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}
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}
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} else if (flow->dl_type == htons(ETH_TYPE_ARP)) {
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const struct arp_eth_header *arp = pull_arp(&b);
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if (arp && arp->ar_hrd == htons(1)
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&& arp->ar_pro == htons(ETH_TYPE_IP)
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&& arp->ar_hln == ETH_ADDR_LEN
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&& arp->ar_pln == 4) {
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/* We only match on the lower 8 bits of the opcode. */
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if (ntohs(arp->ar_op) <= 0xff) {
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flow->nw_proto = ntohs(arp->ar_op);
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}
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if ((flow->nw_proto == ARP_OP_REQUEST)
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|| (flow->nw_proto == ARP_OP_REPLY)) {
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flow->nw_src = arp->ar_spa;
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flow->nw_dst = arp->ar_tpa;
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}
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}
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}
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return retval;
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}
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/* Extracts the flow stats for a packet. The 'flow' and 'packet'
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* arguments must have been initialized through a call to flow_extract().
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*/
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void
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flow_extract_stats(const struct flow *flow, struct ofpbuf *packet,
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struct odp_flow_stats *stats)
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{
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memset(stats, '\0', sizeof(*stats));
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if ((flow->dl_type == htons(ETH_TYPE_IP)) && packet->l4) {
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if ((flow->nw_proto == IP_TYPE_TCP) && packet->l7) {
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struct tcp_header *tcp = packet->l4;
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stats->tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
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}
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}
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stats->n_bytes = packet->size;
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stats->n_packets = 1;
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}
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/* Extract 'flow' with 'wildcards' into the OpenFlow match structure
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* 'match'. 'flow_format' should be one of NXFF_*. */
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void
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flow_to_match(const struct flow *flow, uint32_t wildcards,
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int flow_format, struct ofp_match *match)
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{
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if (flow_format != NXFF_TUN_ID_FROM_COOKIE) {
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wildcards &= OFPFW_ALL;
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}
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match->wildcards = htonl(wildcards);
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match->in_port = htons(flow->in_port == ODPP_LOCAL ? OFPP_LOCAL
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: flow->in_port);
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match->dl_vlan = flow->dl_vlan;
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match->dl_vlan_pcp = flow->dl_vlan_pcp;
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memcpy(match->dl_src, flow->dl_src, ETH_ADDR_LEN);
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memcpy(match->dl_dst, flow->dl_dst, ETH_ADDR_LEN);
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match->dl_type = flow->dl_type;
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match->nw_src = flow->nw_src;
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match->nw_dst = flow->nw_dst;
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match->nw_tos = flow->nw_tos;
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match->nw_proto = flow->nw_proto;
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match->tp_src = flow->tp_src;
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match->tp_dst = flow->tp_dst;
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memset(match->pad1, '\0', sizeof match->pad1);
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memset(match->pad2, '\0', sizeof match->pad2);
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}
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void
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flow_from_match(const struct ofp_match *match, int flow_format,
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ovs_be64 cookie, struct flow *flow,
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struct flow_wildcards *wc)
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{
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flow_wildcards_init(wc, ntohl(match->wildcards));
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if (flow_format == NXFF_TUN_ID_FROM_COOKIE
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&& !(wc->wildcards & NXFW_TUN_ID)) {
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flow->tun_id = htonl(ntohll(cookie) >> 32);
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} else {
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wc->wildcards |= NXFW_TUN_ID;
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flow->tun_id = 0;
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}
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flow->nw_src = match->nw_src;
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flow->nw_dst = match->nw_dst;
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flow->in_port = (match->in_port == htons(OFPP_LOCAL) ? ODPP_LOCAL
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: ntohs(match->in_port));
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flow->dl_vlan = match->dl_vlan;
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flow->dl_vlan_pcp = match->dl_vlan_pcp;
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flow->dl_type = match->dl_type;
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flow->tp_src = match->tp_src;
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flow->tp_dst = match->tp_dst;
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memcpy(flow->dl_src, match->dl_src, ETH_ADDR_LEN);
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memcpy(flow->dl_dst, match->dl_dst, ETH_ADDR_LEN);
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flow->nw_tos = match->nw_tos;
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flow->nw_proto = match->nw_proto;
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}
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char *
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flow_to_string(const struct flow *flow)
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{
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struct ds ds = DS_EMPTY_INITIALIZER;
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flow_format(&ds, flow);
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return ds_cstr(&ds);
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}
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void
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flow_format(struct ds *ds, const struct flow *flow)
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{
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ds_put_format(ds, "tunnel%08"PRIx32":in_port%04"PRIx16
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":vlan%"PRIu16":pcp%"PRIu8
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" mac"ETH_ADDR_FMT"->"ETH_ADDR_FMT
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" type%04"PRIx16
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" proto%"PRIu8
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" tos%"PRIu8
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" ip"IP_FMT"->"IP_FMT
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" port%"PRIu16"->%"PRIu16,
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ntohl(flow->tun_id),
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flow->in_port,
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ntohs(flow->dl_vlan),
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flow->dl_vlan_pcp,
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ETH_ADDR_ARGS(flow->dl_src),
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ETH_ADDR_ARGS(flow->dl_dst),
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ntohs(flow->dl_type),
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flow->nw_proto,
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flow->nw_tos,
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IP_ARGS(&flow->nw_src),
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IP_ARGS(&flow->nw_dst),
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ntohs(flow->tp_src),
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ntohs(flow->tp_dst));
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}
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void
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flow_print(FILE *stream, const struct flow *flow)
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{
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char *s = flow_to_string(flow);
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fputs(s, stream);
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free(s);
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}
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/* flow_wildcards functions. */
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/* Given the wildcard bit count in bits 'shift' through 'shift + 5' (inclusive)
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* of 'wildcards', returns a 32-bit bit mask with a 1 in each bit that must
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* match and a 0 in each bit that is wildcarded.
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*
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* The bits in 'wildcards' are in the format used in enum ofp_flow_wildcards: 0
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* is exact match, 1 ignores the LSB, 2 ignores the 2 least-significant bits,
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* ..., 32 and higher wildcard the entire field. This is the *opposite* of the
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* usual convention where e.g. /24 indicates that 8 bits (not 24 bits) are
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* wildcarded. */
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ovs_be32
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flow_nw_bits_to_mask(uint32_t wildcards, int shift)
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{
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wildcards = (wildcards >> shift) & 0x3f;
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return wildcards < 32 ? htonl(~((1u << wildcards) - 1)) : 0;
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}
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/* Return 'wildcards' in "normal form":
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*
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* - Forces unknown bits to 0.
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*
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* - Forces nw_src and nw_dst masks greater than 32 to exactly 32.
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*/
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static inline uint32_t
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flow_wildcards_normalize(uint32_t wildcards)
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{
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wildcards &= wildcards & OVSFW_ALL;
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if (wildcards & (0x20 << OFPFW_NW_SRC_SHIFT)) {
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wildcards &= ~(0x1f << OFPFW_NW_SRC_SHIFT);
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}
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if (wildcards & (0x20 << OFPFW_NW_DST_SHIFT)) {
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wildcards &= ~(0x1f << OFPFW_NW_DST_SHIFT);
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}
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return wildcards;
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}
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/* Initializes 'wc' from 'wildcards', which may be any combination of the
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* OFPFW_* and OVSFW_* wildcard bits. */
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void
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flow_wildcards_init(struct flow_wildcards *wc, uint32_t wildcards)
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{
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wc->wildcards = flow_wildcards_normalize(wildcards);
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wc->nw_src_mask = flow_nw_bits_to_mask(wc->wildcards, OFPFW_NW_SRC_SHIFT);
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wc->nw_dst_mask = flow_nw_bits_to_mask(wc->wildcards, OFPFW_NW_DST_SHIFT);
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}
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/* Initializes 'wc' as an exact-match set of wildcards; that is, 'wc' does not
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* wildcard any bits or fields. */
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void
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flow_wildcards_init_exact(struct flow_wildcards *wc)
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{
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flow_wildcards_init(wc, 0);
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}
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static inline uint32_t
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combine_nw_bits(uint32_t wb1, uint32_t wb2, int shift)
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{
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uint32_t sb1 = (wb1 >> shift) & 0x3f;
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uint32_t sb2 = (wb2 >> shift) & 0x3f;
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return MAX(sb1, sb2) << shift;
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}
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/* Initializes 'dst' as the combination of wildcards in 'src1' and 'src2'.
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* That is, a bit or a field is wildcarded in 'dst' if it is wildcarded in
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* 'src1' or 'src2' or both. */
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void
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flow_wildcards_combine(struct flow_wildcards *dst,
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const struct flow_wildcards *src1,
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const struct flow_wildcards *src2)
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{
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uint32_t wb1 = src1->wildcards;
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uint32_t wb2 = src2->wildcards;
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dst->wildcards = (wb1 | wb2) & ~(OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK);
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dst->wildcards |= combine_nw_bits(wb1, wb2, OFPFW_NW_SRC_SHIFT);
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dst->wildcards |= combine_nw_bits(wb1, wb2, OFPFW_NW_DST_SHIFT);
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dst->nw_src_mask = src1->nw_src_mask & src2->nw_src_mask;
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dst->nw_dst_mask = src1->nw_dst_mask & src2->nw_dst_mask;
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}
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/* Returns a hash of the wildcards in 'wc'. */
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uint32_t
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flow_wildcards_hash(const struct flow_wildcards *wc)
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{
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/* There is no need to include nw_src_mask or nw_dst_mask because they do
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* not add any information (they can be computed from wc->wildcards). */
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return hash_int(wc->wildcards, 0);
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}
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/* Returns true if 'a' and 'b' represent the same wildcards, false if they are
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* different. */
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bool
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flow_wildcards_equal(const struct flow_wildcards *a,
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const struct flow_wildcards *b)
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{
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return a->wildcards == b->wildcards;
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}
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/* Returns true if at least one bit or field is wildcarded in 'a' but not in
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* 'b', false otherwise. */
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bool
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flow_wildcards_has_extra(const struct flow_wildcards *a,
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const struct flow_wildcards *b)
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{
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#define OFPFW_NW_MASK (OFPFW_NW_SRC_MASK | OFPFW_NW_DST_MASK)
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return ((a->wildcards & ~(b->wildcards | OFPFW_NW_MASK))
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|| (a->nw_src_mask & b->nw_src_mask) != b->nw_src_mask
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|| (a->nw_dst_mask & b->nw_dst_mask) != b->nw_dst_mask);
|
||
}
|
||
|
||
static int
|
||
count_ones(ovs_be32 mask)
|
||
{
|
||
#if __GNUC__ >= 4
|
||
return __builtin_popcount(mask);
|
||
#else
|
||
int bits;
|
||
|
||
for (bits = 0; mask; bits++) {
|
||
mask &= mask - 1;
|
||
}
|
||
|
||
return bits;
|
||
#endif
|
||
}
|
||
|
||
static bool
|
||
set_nw_mask(struct flow_wildcards *wc, ovs_be32 mask,
|
||
ovs_be32 *maskp, int shift)
|
||
{
|
||
int wcbits = 32 - count_ones(mask);
|
||
if (flow_nw_bits_to_mask(wcbits, 0) == mask) {
|
||
wc->wildcards &= ~(0x3f << shift);
|
||
wc->wildcards |= wcbits << shift;
|
||
*maskp = mask;
|
||
return true;
|
||
} else {
|
||
return false;
|
||
}
|
||
}
|
||
|
||
/* Sets the IP (or ARP) source wildcard mask to CIDR 'mask' (consisting of N
|
||
* high-order 1-bit and 32-N low-order 0-bits). Returns true if successful,
|
||
* false if 'mask' is not a CIDR mask. */
|
||
bool
|
||
flow_wildcards_set_nw_src_mask(struct flow_wildcards *wc, ovs_be32 mask)
|
||
{
|
||
return set_nw_mask(wc, mask, &wc->nw_src_mask, OFPFW_NW_SRC_SHIFT);
|
||
}
|
||
|
||
/* Sets the IP (or ARP) destination wildcard mask to CIDR 'mask' (consisting of
|
||
* N high-order 1-bit and 32-N low-order 0-bits). Returns true if successful,
|
||
* false if 'mask' is not a CIDR mask. */
|
||
bool
|
||
flow_wildcards_set_nw_dst_mask(struct flow_wildcards *wc, ovs_be32 mask)
|
||
{
|
||
return set_nw_mask(wc, mask, &wc->nw_dst_mask, OFPFW_NW_DST_SHIFT);
|
||
}
|