/* Copyright (c) 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include "bfd.h" #include #include #include #include #include "byte-order.h" #include "connectivity.h" #include "csum.h" #include "dpif.h" #include "dynamic-string.h" #include "flow.h" #include "hash.h" #include "hmap.h" #include "list.h" #include "netdev.h" #include "netlink.h" #include "odp-util.h" #include "ofpbuf.h" #include "ovs-thread.h" #include "openvswitch/types.h" #include "packets.h" #include "poll-loop.h" #include "random.h" #include "seq.h" #include "smap.h" #include "timeval.h" #include "unaligned.h" #include "unixctl.h" #include "util.h" #include "vlog.h" VLOG_DEFINE_THIS_MODULE(bfd); /* XXX Finish BFD. * * The goal of this module is to replace CFM with something both more flexible * and standards compliant. In service of this goal, the following needs to be * done. * * - Compliance * * Implement Demand mode. * * Go through the RFC line by line and verify we comply. * * Test against a hardware implementation. Preferably a popular one. * * Delete BFD packets with nw_ttl != 255 in the datapath to prevent DOS * attacks. * * - Unit tests. * * - Set TOS/PCP on the outer tunnel header when encapped. * * - Sending BFD messages should be in its own thread/process. * * - Scale testing. How does it operate when there are large number of bfd * sessions? Do we ever have random flaps? What's the CPU utilization? * * - Rely on data traffic for liveness by using BFD demand mode. * If we're receiving traffic on a port, we can safely assume it's up (modulo * unidrectional failures). BFD has a demand mode in which it can stay quiet * unless it feels the need to check the status of the port. Using this, we * can implement a strategy in which BFD only sends control messages on dark * interfaces. * * - Depending on how one interprets the spec, it appears that a BFD session * can never change bfd.LocalDiag to "No Diagnostic". We should verify that * this is what hardware implementations actually do. Seems like "No * Diagnostic" should be set once a BFD session state goes UP. */ #define BFD_VERSION 1 enum flags { FLAG_MULTIPOINT = 1 << 0, FLAG_DEMAND = 1 << 1, FLAG_AUTH = 1 << 2, FLAG_CTL = 1 << 3, FLAG_FINAL = 1 << 4, FLAG_POLL = 1 << 5 }; enum state { STATE_ADMIN_DOWN = 0 << 6, STATE_DOWN = 1 << 6, STATE_INIT = 2 << 6, STATE_UP = 3 << 6 }; enum diag { DIAG_NONE = 0, /* No Diagnostic. */ DIAG_EXPIRED = 1, /* Control Detection Time Expired. */ DIAG_ECHO_FAILED = 2, /* Echo Function Failed. */ DIAG_RMT_DOWN = 3, /* Neighbor Signaled Session Down. */ DIAG_FWD_RESET = 4, /* Forwarding Plane Reset. */ DIAG_PATH_DOWN = 5, /* Path Down. */ DIAG_CPATH_DOWN = 6, /* Concatenated Path Down. */ DIAG_ADMIN_DOWN = 7, /* Administratively Down. */ DIAG_RCPATH_DOWN = 8 /* Reverse Concatenated Path Down. */ }; /* RFC 5880 Section 4.1 * 0 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |Vers | Diag |Sta|P|F|C|A|D|M| Detect Mult | Length | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | My Discriminator | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Your Discriminator | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Desired Min TX Interval | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Required Min RX Interval | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Required Min Echo RX Interval | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ struct msg { uint8_t vers_diag; /* Version and diagnostic. */ uint8_t flags; /* 2bit State field followed by flags. */ uint8_t mult; /* Fault detection multiplier. */ uint8_t length; /* Length of this BFD message. */ ovs_be32 my_disc; /* My discriminator. */ ovs_be32 your_disc; /* Your discriminator. */ ovs_be32 min_tx; /* Desired minimum tx interval. */ ovs_be32 min_rx; /* Required minimum rx interval. */ ovs_be32 min_rx_echo; /* Required minimum echo rx interval. */ }; BUILD_ASSERT_DECL(BFD_PACKET_LEN == sizeof(struct msg)); #define DIAG_MASK 0x1f #define VERS_SHIFT 5 #define STATE_MASK 0xC0 #define FLAGS_MASK 0x3f struct bfd { struct hmap_node node; /* In 'all_bfds'. */ uint32_t disc; /* bfd.LocalDiscr. Key in 'all_bfds' hmap. */ char *name; /* Name used for logging. */ bool cpath_down; /* Concatenated Path Down. */ uint8_t mult; /* bfd.DetectMult. */ struct netdev *netdev; uint64_t rx_packets; /* Packets received by 'netdev'. */ enum state state; /* bfd.SessionState. */ enum state rmt_state; /* bfd.RemoteSessionState. */ enum diag diag; /* bfd.LocalDiag. */ enum diag rmt_diag; /* Remote diagnostic. */ enum flags flags; /* Flags sent on messages. */ enum flags rmt_flags; /* Flags last received. */ uint32_t rmt_disc; /* bfd.RemoteDiscr. */ uint8_t eth_dst[ETH_ADDR_LEN];/* Ethernet destination address. */ bool eth_dst_set; /* 'eth_dst' set through database. */ ovs_be32 ip_src; /* IPv4 source address. */ ovs_be32 ip_dst; /* IPv4 destination address. */ uint16_t udp_src; /* UDP source port. */ /* All timers in milliseconds. */ long long int rmt_min_rx; /* bfd.RemoteMinRxInterval. */ long long int rmt_min_tx; /* Remote minimum TX interval. */ long long int cfg_min_tx; /* Configured minimum TX rate. */ long long int cfg_min_rx; /* Configured required minimum RX rate. */ long long int poll_min_tx; /* Min TX negotating in a poll sequence. */ long long int poll_min_rx; /* Min RX negotating in a poll sequence. */ long long int min_tx; /* bfd.DesiredMinTxInterval. */ long long int min_rx; /* bfd.RequiredMinRxInterval. */ long long int last_tx; /* Last TX time. */ long long int next_tx; /* Next TX time. */ long long int detect_time; /* RFC 5880 6.8.4 Detection time. */ bool last_forwarding; /* Last calculation of forwarding flag. */ int forwarding_override; /* Manual override of 'forwarding' status. */ atomic_bool check_tnl_key; /* Verify tunnel key of inbound packets? */ struct ovs_refcount ref_cnt; /* When forward_if_rx is true, bfd_forwarding() will return * true as long as there are incoming packets received. * Note, forwarding_override still has higher priority. */ bool forwarding_if_rx; long long int forwarding_if_rx_detect_time; /* BFD decay related variables. */ bool in_decay; /* True when bfd is in decay. */ int decay_min_rx; /* min_rx is set to decay_min_rx when */ /* in decay. */ int decay_rx_ctl; /* Count bfd packets received within decay */ /* detect interval. */ uint64_t decay_rx_packets; /* Packets received by 'netdev'. */ long long int decay_detect_time; /* Decay detection time. */ uint64_t flap_count; /* Counts bfd forwarding flaps. */ }; static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER; static struct hmap all_bfds__ = HMAP_INITIALIZER(&all_bfds__); static struct hmap *const all_bfds OVS_GUARDED_BY(mutex) = &all_bfds__; static bool bfd_lookup_ip(const char *host_name, struct in_addr *) OVS_REQUIRES(mutex); static bool bfd_forwarding__(struct bfd *) OVS_REQUIRES(mutex); static bool bfd_in_poll(const struct bfd *) OVS_REQUIRES(mutex); static void bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex); static const char *bfd_diag_str(enum diag) OVS_REQUIRES(mutex); static const char *bfd_state_str(enum state) OVS_REQUIRES(mutex); static long long int bfd_min_tx(const struct bfd *) OVS_REQUIRES(mutex); static long long int bfd_tx_interval(const struct bfd *) OVS_REQUIRES(mutex); static long long int bfd_rx_interval(const struct bfd *) OVS_REQUIRES(mutex); static void bfd_set_next_tx(struct bfd *) OVS_REQUIRES(mutex); static void bfd_set_state(struct bfd *, enum state, enum diag) OVS_REQUIRES(mutex); static uint32_t generate_discriminator(void) OVS_REQUIRES(mutex); static void bfd_put_details(struct ds *, const struct bfd *) OVS_REQUIRES(mutex); static uint64_t bfd_rx_packets(const struct bfd *) OVS_REQUIRES(mutex); static void bfd_try_decay(struct bfd *) OVS_REQUIRES(mutex); static void bfd_decay_update(struct bfd *) OVS_REQUIRES(mutex); static void bfd_forwarding_if_rx_update(struct bfd *) OVS_REQUIRES(mutex); static void bfd_unixctl_show(struct unixctl_conn *, int argc, const char *argv[], void *aux OVS_UNUSED); static void bfd_unixctl_set_forwarding_override(struct unixctl_conn *, int argc, const char *argv[], void *aux OVS_UNUSED); static void log_msg(enum vlog_level, const struct msg *, const char *message, const struct bfd *) OVS_REQUIRES(mutex); static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20); /* Returns true if the interface on which 'bfd' is running may be used to * forward traffic according to the BFD session state. */ bool bfd_forwarding(struct bfd *bfd) OVS_EXCLUDED(mutex) { bool ret; ovs_mutex_lock(&mutex); ret = bfd_forwarding__(bfd); ovs_mutex_unlock(&mutex); return ret; } /* When forwarding_if_rx is enabled, if there are packets received, * updates forwarding_if_rx_detect_time. */ void bfd_account_rx(struct bfd *bfd, const struct dpif_flow_stats *stats) { if (stats->n_packets && bfd->forwarding_if_rx) { ovs_mutex_lock(&mutex); bfd_forwarding__(bfd); bfd_forwarding_if_rx_update(bfd); bfd_forwarding__(bfd); ovs_mutex_unlock(&mutex); } } /* Returns a 'smap' of key value pairs representing the status of 'bfd' * intended for the OVS database. */ void bfd_get_status(const struct bfd *bfd, struct smap *smap) OVS_EXCLUDED(mutex) { ovs_mutex_lock(&mutex); smap_add(smap, "forwarding", bfd_forwarding__(CONST_CAST(struct bfd *, bfd)) ? "true" : "false"); smap_add(smap, "state", bfd_state_str(bfd->state)); smap_add(smap, "diagnostic", bfd_diag_str(bfd->diag)); smap_add_format(smap, "flap_count", "%"PRIu64, bfd->flap_count); if (bfd->state != STATE_DOWN) { smap_add(smap, "remote_state", bfd_state_str(bfd->rmt_state)); smap_add(smap, "remote_diagnostic", bfd_diag_str(bfd->rmt_diag)); } ovs_mutex_unlock(&mutex); } /* Initializes, destroys, or reconfigures the BFD session 'bfd' (named 'name'), * according to the database configuration contained in 'cfg'. Takes ownership * of 'bfd', which may be NULL. Returns a BFD object which may be used as a * handle for the session, or NULL if BFD is not enabled according to 'cfg'. * Also returns NULL if cfg is NULL. */ struct bfd * bfd_configure(struct bfd *bfd, const char *name, const struct smap *cfg, struct netdev *netdev) OVS_EXCLUDED(mutex) { static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER; static atomic_uint16_t udp_src = ATOMIC_VAR_INIT(0); int decay_min_rx; long long int min_tx, min_rx; bool need_poll = false; bool cfg_min_rx_changed = false; bool cpath_down, forwarding_if_rx; const char *hwaddr, *ip_src, *ip_dst; struct in_addr in_addr; uint8_t ea[ETH_ADDR_LEN]; if (ovsthread_once_start(&once)) { unixctl_command_register("bfd/show", "[interface]", 0, 1, bfd_unixctl_show, NULL); unixctl_command_register("bfd/set-forwarding", "[interface] normal|false|true", 1, 2, bfd_unixctl_set_forwarding_override, NULL); ovsthread_once_done(&once); } if (!cfg || !smap_get_bool(cfg, "enable", false)) { bfd_unref(bfd); return NULL; } ovs_mutex_lock(&mutex); if (!bfd) { bfd = xzalloc(sizeof *bfd); bfd->name = xstrdup(name); bfd->forwarding_override = -1; bfd->disc = generate_discriminator(); hmap_insert(all_bfds, &bfd->node, bfd->disc); bfd->diag = DIAG_NONE; bfd->min_tx = 1000; bfd->mult = 3; ovs_refcount_init(&bfd->ref_cnt); bfd->netdev = netdev_ref(netdev); bfd->rx_packets = bfd_rx_packets(bfd); bfd->in_decay = false; bfd->flap_count = 0; /* RFC 5881 section 4 * The source port MUST be in the range 49152 through 65535. The same * UDP source port number MUST be used for all BFD Control packets * associated with a particular session. The source port number SHOULD * be unique among all BFD sessions on the system. */ atomic_add(&udp_src, 1, &bfd->udp_src); bfd->udp_src = (bfd->udp_src % 16384) + 49152; bfd_set_state(bfd, STATE_DOWN, DIAG_NONE); memcpy(bfd->eth_dst, eth_addr_bfd, ETH_ADDR_LEN); } atomic_store(&bfd->check_tnl_key, smap_get_bool(cfg, "check_tnl_key", false)); min_tx = smap_get_int(cfg, "min_tx", 100); min_tx = MAX(min_tx, 100); if (bfd->cfg_min_tx != min_tx) { bfd->cfg_min_tx = min_tx; if (bfd->state != STATE_UP || (!bfd_in_poll(bfd) && bfd->cfg_min_tx < bfd->min_tx)) { bfd->min_tx = bfd->cfg_min_tx; } need_poll = true; } min_rx = smap_get_int(cfg, "min_rx", 1000); min_rx = MAX(min_rx, 100); if (bfd->cfg_min_rx != min_rx) { bfd->cfg_min_rx = min_rx; if (bfd->state != STATE_UP || (!bfd_in_poll(bfd) && bfd->cfg_min_rx > bfd->min_rx)) { bfd->min_rx = bfd->cfg_min_rx; } cfg_min_rx_changed = true; need_poll = true; } decay_min_rx = smap_get_int(cfg, "decay_min_rx", 0); if (bfd->decay_min_rx != decay_min_rx || cfg_min_rx_changed) { if (decay_min_rx > 0 && decay_min_rx < bfd->cfg_min_rx) { VLOG_WARN("%s: decay_min_rx cannot be less than %lld ms", bfd->name, bfd->cfg_min_rx); bfd->decay_min_rx = 0; } else { bfd->decay_min_rx = decay_min_rx; } /* Resets decay. */ bfd->in_decay = false; bfd_decay_update(bfd); need_poll = true; } cpath_down = smap_get_bool(cfg, "cpath_down", false); if (bfd->cpath_down != cpath_down) { bfd->cpath_down = cpath_down; bfd_set_state(bfd, bfd->state, DIAG_NONE); need_poll = true; } hwaddr = smap_get(cfg, "bfd_dst_mac"); if (hwaddr && eth_addr_from_string(hwaddr, ea) && !eth_addr_is_zero(ea)) { memcpy(bfd->eth_dst, ea, ETH_ADDR_LEN); bfd->eth_dst_set = true; } else if (bfd->eth_dst_set) { memcpy(bfd->eth_dst, eth_addr_bfd, ETH_ADDR_LEN); bfd->eth_dst_set = false; } ip_src = smap_get(cfg, "bfd_src_ip"); if (ip_src && bfd_lookup_ip(ip_src, &in_addr)) { memcpy(&bfd->ip_src, &in_addr, sizeof in_addr); } else { bfd->ip_src = htonl(0xA9FE0100); /* 169.254.1.0. */ } ip_dst = smap_get(cfg, "bfd_dst_ip"); if (ip_dst && bfd_lookup_ip(ip_dst, &in_addr)) { memcpy(&bfd->ip_dst, &in_addr, sizeof in_addr); } else { bfd->ip_dst = htonl(0xA9FE0101); /* 169.254.1.1. */ } forwarding_if_rx = smap_get_bool(cfg, "forwarding_if_rx", false); if (bfd->forwarding_if_rx != forwarding_if_rx) { bfd->forwarding_if_rx = forwarding_if_rx; if (bfd->state == STATE_UP && bfd->forwarding_if_rx) { bfd_forwarding_if_rx_update(bfd); } else { bfd->forwarding_if_rx_detect_time = 0; } } if (need_poll) { bfd_poll(bfd); } ovs_mutex_unlock(&mutex); return bfd; } struct bfd * bfd_ref(const struct bfd *bfd_) { struct bfd *bfd = CONST_CAST(struct bfd *, bfd_); if (bfd) { ovs_refcount_ref(&bfd->ref_cnt); } return bfd; } void bfd_unref(struct bfd *bfd) OVS_EXCLUDED(mutex) { if (bfd && ovs_refcount_unref(&bfd->ref_cnt) == 1) { ovs_mutex_lock(&mutex); hmap_remove(all_bfds, &bfd->node); netdev_close(bfd->netdev); ovs_refcount_destroy(&bfd->ref_cnt); free(bfd->name); free(bfd); ovs_mutex_unlock(&mutex); } } void bfd_wait(const struct bfd *bfd) OVS_EXCLUDED(mutex) { poll_timer_wait_until(bfd_wake_time(bfd)); } /* Returns the next wake up time. */ long long int bfd_wake_time(const struct bfd *bfd) OVS_EXCLUDED(mutex) { long long int retval; if (!bfd) { return LLONG_MAX; } ovs_mutex_lock(&mutex); if (bfd->flags & FLAG_FINAL) { retval = 0; } else { retval = bfd->next_tx; if (bfd->state > STATE_DOWN) { retval = MIN(bfd->detect_time, retval); } } ovs_mutex_unlock(&mutex); return retval; } void bfd_run(struct bfd *bfd) OVS_EXCLUDED(mutex) { long long int now; bool old_in_decay; ovs_mutex_lock(&mutex); now = time_msec(); old_in_decay = bfd->in_decay; if (bfd->state > STATE_DOWN && now >= bfd->detect_time) { bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED); } bfd_forwarding__(bfd); /* Decay may only happen when state is STATE_UP, bfd->decay_min_rx is * configured, and decay_detect_time is reached. */ if (bfd->state == STATE_UP && bfd->decay_min_rx > 0 && now >= bfd->decay_detect_time) { bfd_try_decay(bfd); } if (bfd->min_tx != bfd->cfg_min_tx || (bfd->min_rx != bfd->cfg_min_rx && bfd->min_rx != bfd->decay_min_rx) || bfd->in_decay != old_in_decay) { bfd_poll(bfd); } ovs_mutex_unlock(&mutex); } bool bfd_should_send_packet(const struct bfd *bfd) OVS_EXCLUDED(mutex) { bool ret; ovs_mutex_lock(&mutex); ret = bfd->flags & FLAG_FINAL || time_msec() >= bfd->next_tx; ovs_mutex_unlock(&mutex); return ret; } void bfd_put_packet(struct bfd *bfd, struct ofpbuf *p, uint8_t eth_src[ETH_ADDR_LEN]) OVS_EXCLUDED(mutex) { long long int min_tx, min_rx; struct udp_header *udp; struct eth_header *eth; struct ip_header *ip; struct msg *msg; ovs_mutex_lock(&mutex); if (bfd->next_tx) { long long int delay = time_msec() - bfd->next_tx; long long int interval = bfd_tx_interval(bfd); if (delay > interval * 3 / 2) { VLOG_INFO("%s: long delay of %lldms (expected %lldms) sending BFD" " control message", bfd->name, delay, interval); } } /* RFC 5880 Section 6.5 * A BFD Control packet MUST NOT have both the Poll (P) and Final (F) bits * set. */ ovs_assert(!(bfd->flags & FLAG_POLL) || !(bfd->flags & FLAG_FINAL)); ofpbuf_reserve(p, 2); /* Properly align after the ethernet header. */ eth = ofpbuf_put_uninit(p, sizeof *eth); memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN); memcpy(eth->eth_dst, bfd->eth_dst, ETH_ADDR_LEN); eth->eth_type = htons(ETH_TYPE_IP); ip = ofpbuf_put_zeros(p, sizeof *ip); ip->ip_ihl_ver = IP_IHL_VER(5, 4); ip->ip_tot_len = htons(sizeof *ip + sizeof *udp + sizeof *msg); ip->ip_ttl = MAXTTL; ip->ip_tos = IPTOS_LOWDELAY | IPTOS_THROUGHPUT; ip->ip_proto = IPPROTO_UDP; put_16aligned_be32(&ip->ip_src, bfd->ip_src); put_16aligned_be32(&ip->ip_dst, bfd->ip_dst); ip->ip_csum = csum(ip, sizeof *ip); udp = ofpbuf_put_zeros(p, sizeof *udp); udp->udp_src = htons(bfd->udp_src); udp->udp_dst = htons(BFD_DEST_PORT); udp->udp_len = htons(sizeof *udp + sizeof *msg); msg = ofpbuf_put_uninit(p, sizeof *msg); msg->vers_diag = (BFD_VERSION << 5) | bfd->diag; msg->flags = (bfd->state & STATE_MASK) | bfd->flags; msg->mult = bfd->mult; msg->length = BFD_PACKET_LEN; msg->my_disc = htonl(bfd->disc); msg->your_disc = htonl(bfd->rmt_disc); msg->min_rx_echo = htonl(0); if (bfd_in_poll(bfd)) { min_tx = bfd->poll_min_tx; min_rx = bfd->poll_min_rx; } else { min_tx = bfd_min_tx(bfd); min_rx = bfd->min_rx; } msg->min_tx = htonl(min_tx * 1000); msg->min_rx = htonl(min_rx * 1000); bfd->flags &= ~FLAG_FINAL; log_msg(VLL_DBG, msg, "Sending BFD Message", bfd); bfd->last_tx = time_msec(); bfd_set_next_tx(bfd); ovs_mutex_unlock(&mutex); } bool bfd_should_process_flow(const struct bfd *bfd_, const struct flow *flow, struct flow_wildcards *wc) { struct bfd *bfd = CONST_CAST(struct bfd *, bfd_); bool check_tnl_key; memset(&wc->masks.dl_dst, 0xff, sizeof wc->masks.dl_dst); if (bfd->eth_dst_set && memcmp(bfd->eth_dst, flow->dl_dst, ETH_ADDR_LEN)) { return false; } memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto); memset(&wc->masks.tp_dst, 0xff, sizeof wc->masks.tp_dst); atomic_read(&bfd->check_tnl_key, &check_tnl_key); if (check_tnl_key) { memset(&wc->masks.tunnel.tun_id, 0xff, sizeof wc->masks.tunnel.tun_id); } return (flow->dl_type == htons(ETH_TYPE_IP) && flow->nw_proto == IPPROTO_UDP && flow->tp_dst == htons(BFD_DEST_PORT) && (!check_tnl_key || flow->tunnel.tun_id == htonll(0))); } void bfd_process_packet(struct bfd *bfd, const struct flow *flow, const struct ofpbuf *p) OVS_EXCLUDED(mutex) { uint32_t rmt_min_rx, pkt_your_disc; enum state rmt_state; enum flags flags; uint8_t version; struct msg *msg; /* This function is designed to follow section RFC 5880 6.8.6 closely. */ ovs_mutex_lock(&mutex); /* Increments the decay rx counter. */ bfd->decay_rx_ctl++; bfd_forwarding__(bfd); if (flow->nw_ttl != 255) { /* XXX Should drop in the kernel to prevent DOS. */ goto out; } msg = ofpbuf_at(p, (uint8_t *)p->l7 - (uint8_t *)p->data, BFD_PACKET_LEN); if (!msg) { VLOG_INFO_RL(&rl, "%s: Received too-short BFD control message (only " "%"PRIdPTR" bytes long, at least %d required).", bfd->name, (uint8_t *) ofpbuf_tail(p) - (uint8_t *) p->l7, BFD_PACKET_LEN); goto out; } /* RFC 5880 Section 6.8.6 * If the Length field is greater than the payload of the encapsulating * protocol, the packet MUST be discarded. * * Note that we make this check implicity. Above we use ofpbuf_at() to * ensure that there are at least BFD_PACKET_LEN bytes in the payload of * the encapsulating protocol. Below we require msg->length to be exactly * BFD_PACKET_LEN bytes. */ flags = msg->flags & FLAGS_MASK; rmt_state = msg->flags & STATE_MASK; version = msg->vers_diag >> VERS_SHIFT; log_msg(VLL_DBG, msg, "Received BFD control message", bfd); if (version != BFD_VERSION) { log_msg(VLL_WARN, msg, "Incorrect version", bfd); goto out; } /* Technically this should happen after the length check. We don't support * authentication however, so it's simpler to do the check first. */ if (flags & FLAG_AUTH) { log_msg(VLL_WARN, msg, "Authenticated control message with" " authentication disabled", bfd); goto out; } if (msg->length != BFD_PACKET_LEN) { log_msg(VLL_WARN, msg, "Unexpected length", bfd); if (msg->length < BFD_PACKET_LEN) { goto out; } } if (!msg->mult) { log_msg(VLL_WARN, msg, "Zero multiplier", bfd); goto out; } if (flags & FLAG_MULTIPOINT) { log_msg(VLL_WARN, msg, "Unsupported multipoint flag", bfd); goto out; } if (!msg->my_disc) { log_msg(VLL_WARN, msg, "NULL my_disc", bfd); goto out; } pkt_your_disc = ntohl(msg->your_disc); if (pkt_your_disc) { /* Technically, we should use the your discriminator field to figure * out which 'struct bfd' this packet is destined towards. That way a * bfd session could migrate from one interface to another * transparently. This doesn't fit in with the OVS structure very * well, so in this respect, we are not compliant. */ if (pkt_your_disc != bfd->disc) { log_msg(VLL_WARN, msg, "Incorrect your_disc", bfd); goto out; } } else if (rmt_state > STATE_DOWN) { log_msg(VLL_WARN, msg, "Null your_disc", bfd); goto out; } if (bfd->rmt_state != rmt_state) { seq_change(connectivity_seq_get()); } bfd->rmt_disc = ntohl(msg->my_disc); bfd->rmt_state = rmt_state; bfd->rmt_flags = flags; bfd->rmt_diag = msg->vers_diag & DIAG_MASK; if (flags & FLAG_FINAL && bfd_in_poll(bfd)) { bfd->min_tx = bfd->poll_min_tx; bfd->min_rx = bfd->poll_min_rx; bfd->flags &= ~FLAG_POLL; log_msg(VLL_INFO, msg, "Poll sequence terminated", bfd); } if (flags & FLAG_POLL) { /* RFC 5880 Section 6.5 * When the other system receives a Poll, it immediately transmits a * BFD Control packet with the Final (F) bit set, independent of any * periodic BFD Control packets it may be sending * (see section 6.8.7). */ bfd->flags &= ~FLAG_POLL; bfd->flags |= FLAG_FINAL; } rmt_min_rx = MAX(ntohl(msg->min_rx) / 1000, 1); if (bfd->rmt_min_rx != rmt_min_rx) { bfd->rmt_min_rx = rmt_min_rx; if (bfd->next_tx) { bfd_set_next_tx(bfd); } log_msg(VLL_INFO, msg, "New remote min_rx", bfd); } bfd->rmt_min_tx = MAX(ntohl(msg->min_tx) / 1000, 1); bfd->detect_time = bfd_rx_interval(bfd) * bfd->mult + time_msec(); if (bfd->state == STATE_ADMIN_DOWN) { VLOG_DBG_RL(&rl, "Administratively down, dropping control message."); goto out; } if (rmt_state == STATE_ADMIN_DOWN) { if (bfd->state != STATE_DOWN) { bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN); } } else { switch (bfd->state) { case STATE_DOWN: if (rmt_state == STATE_DOWN) { bfd_set_state(bfd, STATE_INIT, bfd->diag); } else if (rmt_state == STATE_INIT) { bfd_set_state(bfd, STATE_UP, bfd->diag); } break; case STATE_INIT: if (rmt_state > STATE_DOWN) { bfd_set_state(bfd, STATE_UP, bfd->diag); } break; case STATE_UP: if (rmt_state <= STATE_DOWN) { bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN); log_msg(VLL_INFO, msg, "Remote signaled STATE_DOWN", bfd); } break; case STATE_ADMIN_DOWN: default: OVS_NOT_REACHED(); } } /* XXX: RFC 5880 Section 6.8.6 Demand mode related calculations here. */ out: bfd_forwarding__(bfd); ovs_mutex_unlock(&mutex); } /* Must be called when the netdev owned by 'bfd' should change. */ void bfd_set_netdev(struct bfd *bfd, const struct netdev *netdev) OVS_EXCLUDED(mutex) { ovs_mutex_lock(&mutex); if (bfd->netdev != netdev) { netdev_close(bfd->netdev); bfd->netdev = netdev_ref(netdev); if (bfd->decay_min_rx && bfd->state == STATE_UP) { bfd_decay_update(bfd); } if (bfd->forwarding_if_rx && bfd->state == STATE_UP) { bfd_forwarding_if_rx_update(bfd); } bfd->rx_packets = bfd_rx_packets(bfd); } ovs_mutex_unlock(&mutex); } /* Updates the forwarding flag. If override is not configured and * the forwarding flag value changes, increments the flap count. * * Note this function may be called multiple times in a function * (e.g. bfd_account_rx) before and after the bfd state or status * change. This is to capture any forwarding flag flap. */ static bool bfd_forwarding__(struct bfd *bfd) OVS_REQUIRES(mutex) { long long int time; bool last_forwarding = bfd->last_forwarding; if (bfd->forwarding_override != -1) { return bfd->forwarding_override == 1; } time = bfd->forwarding_if_rx_detect_time; bfd->last_forwarding = (bfd->state == STATE_UP || (bfd->forwarding_if_rx && time > time_msec())) && bfd->rmt_diag != DIAG_PATH_DOWN && bfd->rmt_diag != DIAG_CPATH_DOWN && bfd->rmt_diag != DIAG_RCPATH_DOWN; if (bfd->last_forwarding != last_forwarding) { bfd->flap_count++; seq_change(connectivity_seq_get()); } return bfd->last_forwarding; } /* Helpers. */ static bool bfd_lookup_ip(const char *host_name, struct in_addr *addr) { if (!inet_aton(host_name, addr)) { VLOG_ERR_RL(&rl, "\"%s\" is not a valid IP address", host_name); return false; } return true; } static bool bfd_in_poll(const struct bfd *bfd) OVS_REQUIRES(mutex) { return (bfd->flags & FLAG_POLL) != 0; } static void bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex) { if (bfd->state > STATE_DOWN && !bfd_in_poll(bfd) && !(bfd->flags & FLAG_FINAL)) { bfd->poll_min_tx = bfd->cfg_min_tx; bfd->poll_min_rx = bfd->in_decay ? bfd->decay_min_rx : bfd->cfg_min_rx; bfd->flags |= FLAG_POLL; bfd->next_tx = 0; VLOG_INFO_RL(&rl, "%s: Initiating poll sequence", bfd->name); } } static long long int bfd_min_tx(const struct bfd *bfd) OVS_REQUIRES(mutex) { /* RFC 5880 Section 6.8.3 * When bfd.SessionState is not Up, the system MUST set * bfd.DesiredMinTxInterval to a value of not less than one second * (1,000,000 microseconds). This is intended to ensure that the * bandwidth consumed by BFD sessions that are not Up is negligible, * particularly in the case where a neighbor may not be running BFD. */ return (bfd->state == STATE_UP ? bfd->min_tx : MAX(bfd->min_tx, 1000)); } static long long int bfd_tx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex) { long long int interval = bfd_min_tx(bfd); return MAX(interval, bfd->rmt_min_rx); } static long long int bfd_rx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex) { return MAX(bfd->min_rx, bfd->rmt_min_tx); } static void bfd_set_next_tx(struct bfd *bfd) OVS_REQUIRES(mutex) { long long int interval = bfd_tx_interval(bfd); interval -= interval * random_range(26) / 100; bfd->next_tx = bfd->last_tx + interval; } static const char * bfd_flag_str(enum flags flags) { struct ds ds = DS_EMPTY_INITIALIZER; static char flag_str[128]; if (!flags) { return "none"; } if (flags & FLAG_MULTIPOINT) { ds_put_cstr(&ds, "multipoint "); } if (flags & FLAG_DEMAND) { ds_put_cstr(&ds, "demand "); } if (flags & FLAG_AUTH) { ds_put_cstr(&ds, "auth "); } if (flags & FLAG_CTL) { ds_put_cstr(&ds, "ctl "); } if (flags & FLAG_FINAL) { ds_put_cstr(&ds, "final "); } if (flags & FLAG_POLL) { ds_put_cstr(&ds, "poll "); } /* Do not copy the trailing whitespace. */ ds_chomp(&ds, ' '); ovs_strlcpy(flag_str, ds_cstr(&ds), sizeof flag_str); ds_destroy(&ds); return flag_str; } static const char * bfd_state_str(enum state state) { switch (state) { case STATE_ADMIN_DOWN: return "admin_down"; case STATE_DOWN: return "down"; case STATE_INIT: return "init"; case STATE_UP: return "up"; default: return "invalid"; } } static const char * bfd_diag_str(enum diag diag) { switch (diag) { case DIAG_NONE: return "No Diagnostic"; case DIAG_EXPIRED: return "Control Detection Time Expired"; case DIAG_ECHO_FAILED: return "Echo Function Failed"; case DIAG_RMT_DOWN: return "Neighbor Signaled Session Down"; case DIAG_FWD_RESET: return "Forwarding Plane Reset"; case DIAG_PATH_DOWN: return "Path Down"; case DIAG_CPATH_DOWN: return "Concatenated Path Down"; case DIAG_ADMIN_DOWN: return "Administratively Down"; case DIAG_RCPATH_DOWN: return "Reverse Concatenated Path Down"; default: return "Invalid Diagnostic"; } }; static void log_msg(enum vlog_level level, const struct msg *p, const char *message, const struct bfd *bfd) OVS_REQUIRES(mutex) { struct ds ds = DS_EMPTY_INITIALIZER; if (vlog_should_drop(THIS_MODULE, level, &rl)) { return; } ds_put_format(&ds, "%s: %s." "\n\tvers:%"PRIu8" diag:\"%s\" state:%s mult:%"PRIu8 " length:%"PRIu8 "\n\tflags: %s" "\n\tmy_disc:0x%"PRIx32" your_disc:0x%"PRIx32 "\n\tmin_tx:%"PRIu32"us (%"PRIu32"ms)" "\n\tmin_rx:%"PRIu32"us (%"PRIu32"ms)" "\n\tmin_rx_echo:%"PRIu32"us (%"PRIu32"ms)", bfd->name, message, p->vers_diag >> VERS_SHIFT, bfd_diag_str(p->vers_diag & DIAG_MASK), bfd_state_str(p->flags & STATE_MASK), p->mult, p->length, bfd_flag_str(p->flags & FLAGS_MASK), ntohl(p->my_disc), ntohl(p->your_disc), ntohl(p->min_tx), ntohl(p->min_tx) / 1000, ntohl(p->min_rx), ntohl(p->min_rx) / 1000, ntohl(p->min_rx_echo), ntohl(p->min_rx_echo) / 1000); bfd_put_details(&ds, bfd); VLOG(level, "%s", ds_cstr(&ds)); ds_destroy(&ds); } static void bfd_set_state(struct bfd *bfd, enum state state, enum diag diag) OVS_REQUIRES(mutex) { if (bfd->cpath_down) { diag = DIAG_CPATH_DOWN; } if (bfd->state != state || bfd->diag != diag) { if (!VLOG_DROP_INFO(&rl)) { struct ds ds = DS_EMPTY_INITIALIZER; ds_put_format(&ds, "%s: BFD state change: %s->%s" " \"%s\"->\"%s\".\n", bfd->name, bfd_state_str(bfd->state), bfd_state_str(state), bfd_diag_str(bfd->diag), bfd_diag_str(diag)); bfd_put_details(&ds, bfd); VLOG_INFO("%s", ds_cstr(&ds)); ds_destroy(&ds); } bfd->state = state; bfd->diag = diag; if (bfd->state <= STATE_DOWN) { bfd->rmt_state = STATE_DOWN; bfd->rmt_diag = DIAG_NONE; bfd->rmt_min_rx = 1; bfd->rmt_flags = 0; bfd->rmt_disc = 0; bfd->rmt_min_tx = 0; /* Resets the min_rx if in_decay. */ if (bfd->in_decay) { bfd->min_rx = bfd->cfg_min_rx; bfd->in_decay = false; } } /* Resets the decay when state changes to STATE_UP * and decay_min_rx is configured. */ if (bfd->state == STATE_UP && bfd->decay_min_rx) { bfd_decay_update(bfd); } seq_change(connectivity_seq_get()); } } static uint64_t bfd_rx_packets(const struct bfd *bfd) OVS_REQUIRES(mutex) { struct netdev_stats stats; if (!netdev_get_stats(bfd->netdev, &stats)) { return stats.rx_packets; } else { return 0; } } /* Decays the bfd->min_rx to bfd->decay_min_rx when 'diff' is less than * the 'expect' value. */ static void bfd_try_decay(struct bfd *bfd) OVS_REQUIRES(mutex) { int64_t diff, expect; /* The 'diff' is the difference between current interface rx_packets * stats and last-time check. The 'expect' is the recorded number of * bfd control packets received within an approximately decay_min_rx * (2000 ms if decay_min_rx is less than 2000 ms) interval. * * Since the update of rx_packets stats at interface happens * asynchronously to the bfd_rx_packets() function, the 'diff' value * can be jittered. Thusly, we double the decay_rx_ctl to provide * more wiggle room. */ diff = bfd_rx_packets(bfd) - bfd->decay_rx_packets; expect = 2 * MAX(bfd->decay_rx_ctl, 1); bfd->in_decay = diff <= expect ? true : false; bfd_decay_update(bfd); } /* Updates the rx_packets, decay_rx_ctl and decay_detect_time. */ static void bfd_decay_update(struct bfd * bfd) OVS_REQUIRES(mutex) { bfd->decay_rx_packets = bfd_rx_packets(bfd); bfd->decay_rx_ctl = 0; bfd->decay_detect_time = MAX(bfd->decay_min_rx, 2000) + time_msec(); } static void bfd_forwarding_if_rx_update(struct bfd *bfd) OVS_REQUIRES(mutex) { int64_t incr = bfd_rx_interval(bfd) * bfd->mult; bfd->forwarding_if_rx_detect_time = MAX(incr, 2000) + time_msec(); } static uint32_t generate_discriminator(void) { uint32_t disc = 0; /* RFC 5880 Section 6.8.1 * It SHOULD be set to a random (but still unique) value to improve * security. The value is otherwise outside the scope of this * specification. */ while (!disc) { struct bfd *bfd; /* 'disc' is by definition random, so there's no reason to waste time * hashing it. */ disc = random_uint32(); HMAP_FOR_EACH_IN_BUCKET (bfd, node, disc, all_bfds) { if (bfd->disc == disc) { disc = 0; break; } } } return disc; } static struct bfd * bfd_find_by_name(const char *name) OVS_REQUIRES(mutex) { struct bfd *bfd; HMAP_FOR_EACH (bfd, node, all_bfds) { if (!strcmp(bfd->name, name)) { return bfd; } } return NULL; } static void bfd_put_details(struct ds *ds, const struct bfd *bfd) OVS_REQUIRES(mutex) { ds_put_format(ds, "\tForwarding: %s\n", bfd_forwarding__(CONST_CAST(struct bfd *, bfd)) ? "true" : "false"); ds_put_format(ds, "\tDetect Multiplier: %d\n", bfd->mult); ds_put_format(ds, "\tConcatenated Path Down: %s\n", bfd->cpath_down ? "true" : "false"); ds_put_format(ds, "\tTX Interval: Approx %lldms\n", bfd_tx_interval(bfd)); ds_put_format(ds, "\tRX Interval: Approx %lldms\n", bfd_rx_interval(bfd)); ds_put_format(ds, "\tDetect Time: now %+lldms\n", time_msec() - bfd->detect_time); ds_put_format(ds, "\tNext TX Time: now %+lldms\n", time_msec() - bfd->next_tx); ds_put_format(ds, "\tLast TX Time: now %+lldms\n", time_msec() - bfd->last_tx); ds_put_cstr(ds, "\n"); ds_put_format(ds, "\tLocal Flags: %s\n", bfd_flag_str(bfd->flags)); ds_put_format(ds, "\tLocal Session State: %s\n", bfd_state_str(bfd->state)); ds_put_format(ds, "\tLocal Diagnostic: %s\n", bfd_diag_str(bfd->diag)); ds_put_format(ds, "\tLocal Discriminator: 0x%"PRIx32"\n", bfd->disc); ds_put_format(ds, "\tLocal Minimum TX Interval: %lldms\n", bfd_min_tx(bfd)); ds_put_format(ds, "\tLocal Minimum RX Interval: %lldms\n", bfd->min_rx); ds_put_cstr(ds, "\n"); ds_put_format(ds, "\tRemote Flags: %s\n", bfd_flag_str(bfd->rmt_flags)); ds_put_format(ds, "\tRemote Session State: %s\n", bfd_state_str(bfd->rmt_state)); ds_put_format(ds, "\tRemote Diagnostic: %s\n", bfd_diag_str(bfd->rmt_diag)); ds_put_format(ds, "\tRemote Discriminator: 0x%"PRIx32"\n", bfd->rmt_disc); ds_put_format(ds, "\tRemote Minimum TX Interval: %lldms\n", bfd->rmt_min_tx); ds_put_format(ds, "\tRemote Minimum RX Interval: %lldms\n", bfd->rmt_min_rx); } static void bfd_unixctl_show(struct unixctl_conn *conn, int argc, const char *argv[], void *aux OVS_UNUSED) OVS_EXCLUDED(mutex) { struct ds ds = DS_EMPTY_INITIALIZER; struct bfd *bfd; ovs_mutex_lock(&mutex); if (argc > 1) { bfd = bfd_find_by_name(argv[1]); if (!bfd) { unixctl_command_reply_error(conn, "no such bfd object"); goto out; } bfd_put_details(&ds, bfd); } else { HMAP_FOR_EACH (bfd, node, all_bfds) { ds_put_format(&ds, "---- %s ----\n", bfd->name); bfd_put_details(&ds, bfd); } } unixctl_command_reply(conn, ds_cstr(&ds)); ds_destroy(&ds); out: ovs_mutex_unlock(&mutex); } static void bfd_unixctl_set_forwarding_override(struct unixctl_conn *conn, int argc, const char *argv[], void *aux OVS_UNUSED) OVS_EXCLUDED(mutex) { const char *forward_str = argv[argc - 1]; int forwarding_override; struct bfd *bfd; ovs_mutex_lock(&mutex); if (!strcasecmp("true", forward_str)) { forwarding_override = 1; } else if (!strcasecmp("false", forward_str)) { forwarding_override = 0; } else if (!strcasecmp("normal", forward_str)) { forwarding_override = -1; } else { unixctl_command_reply_error(conn, "unknown fault string"); goto out; } if (argc > 2) { bfd = bfd_find_by_name(argv[1]); if (!bfd) { unixctl_command_reply_error(conn, "no such BFD object"); goto out; } bfd->forwarding_override = forwarding_override; } else { HMAP_FOR_EACH (bfd, node, all_bfds) { bfd->forwarding_override = forwarding_override; } } unixctl_command_reply(conn, "OK"); out: ovs_mutex_unlock(&mutex); }