On Thu, Sep 17, 2020 at 5:51 AM Dumitru Ceara <dce...@redhat.com> wrote: > > OVN was dropping IP packets destined to IPs owned by logical routers but > only if those IPs are not used for SNAT rules. However, if a packet > doesn't match an existing NAT session and its destination is still a > router owned IP, it can be safely dropped. Otherwise it will trigger an > unnecessary packet-in in stage lr_in_arp_request. > > To achieve that we add flows that drop traffic to router owned SNAT IPs in > table lr_in_arp_resolve. > > Reported-by: Tim Rozet <tro...@redhat.com> > Reported-at: https://bugzilla.redhat.com/1876174 > Signed-off-by: Dumitru Ceara <dce...@redhat.com> > --- > northd/ovn-northd.8.xml | 24 ++++++ > northd/ovn-northd.c | 194 +++++++++++++++++++++++++++-------------------- > tests/ovn.at | 88 +++++++++++++++++++++ > 3 files changed, 225 insertions(+), 81 deletions(-) > > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml > index bd42105..f1c7c9b 100644 > --- a/northd/ovn-northd.8.xml > +++ b/northd/ovn-northd.8.xml > @@ -3089,6 +3089,30 @@ outport = <var>P</var>; > > <li> > <p> > + Traffic with IP destination an address owned by the router should be > + dropped. Such traffic is normally dropped in ingress table > + <code>IP Input</code> except for IPs that are also shared with SNAT > + rules. However, if there was no unSNAT operation that happened > + successfully until this point in the pipeline and the destination IP > + of the packet is still a router owned IP, the packets can be safely > + dropped. > + </p> > + > + <p> > + A priority-1 logical flow with match <code>ip4.dst = {..}</code> > + matches on traffic destined to router owned IPv4 addresses which are > + also SNAT IPs. This flow has action <code>drop;</code>. > + </p> > + > + <p> > + A priority-1 logical flow with match <code>ip6.dst = {..}</code> > + matches on traffic destined to router owned IPv6 addresses which are > + also SNAT IPs. This flow has action <code>drop;</code>. > + </p> > + </li> > + > + <li> > + <p> > Dynamic MAC bindings. These flows resolve MAC-to-IP bindings > that have become known dynamically through ARP or neighbor > discovery. (The ingress table <code>ARP Request</code> will > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c > index cfec6a2..d5d7631 100644 > --- a/northd/ovn-northd.c > +++ b/northd/ovn-northd.c > @@ -623,6 +623,9 @@ struct ovn_datapath { > /* NAT entries configured on the router. */ > struct ovn_nat *nat_entries; > > + /* SNAT IPs used by the router. */ > + struct sset snat_ips; > + > struct ovn_port **localnet_ports; > size_t n_localnet_ports; > > @@ -641,6 +644,10 @@ struct ovn_nat { > struct lport_addresses ext_addrs; > }; > > +static bool > +get_force_snat_ip(struct ovn_datapath *od, const char *key_type, > + struct lport_addresses *laddrs); > + > /* Returns true if a 'nat_entry' is valid, i.e.: > * - parsing was successful. > * - the string yielded exactly one IPv4 address or exactly one IPv6 address. > @@ -663,7 +670,35 @@ nat_entry_is_v6(const struct ovn_nat *nat_entry) > static void > init_nat_entries(struct ovn_datapath *od) > { > - if (!od->nbr || od->nbr->n_nat == 0) { > + struct lport_addresses snat_addrs; > + > + if (!od->nbr) { > + return; > + } > + > + sset_init(&od->snat_ips); > + if (get_force_snat_ip(od, "dnat", &snat_addrs)) { > + if (snat_addrs.n_ipv4_addrs) { > + sset_add(&od->snat_ips, snat_addrs.ipv4_addrs[0].addr_s); > + } > + if (snat_addrs.n_ipv6_addrs) { > + sset_add(&od->snat_ips, snat_addrs.ipv6_addrs[0].addr_s); > + } > + destroy_lport_addresses(&snat_addrs); > + } > + > + memset(&snat_addrs, 0, sizeof(snat_addrs)); > + if (get_force_snat_ip(od, "lb", &snat_addrs)) { > + if (snat_addrs.n_ipv4_addrs) { > + sset_add(&od->snat_ips, snat_addrs.ipv4_addrs[0].addr_s); > + } > + if (snat_addrs.n_ipv6_addrs) { > + sset_add(&od->snat_ips, snat_addrs.ipv6_addrs[0].addr_s); > + } > + destroy_lport_addresses(&snat_addrs); > + } > + > + if (!od->nbr->n_nat) { > return; > } > > @@ -682,6 +717,13 @@ init_nat_entries(struct ovn_datapath *od) > VLOG_WARN_RL(&rl, > "Bad ip address %s in nat configuration " > "for router %s", nat->external_ip, od->nbr->name); > + continue; > + } > + > + if (!nat_entry_is_v6(nat_entry)) { > + sset_add(&od->snat_ips, nat_entry->ext_addrs.ipv4_addrs[0].addr_s); > + } else { > + sset_add(&od->snat_ips, nat_entry->ext_addrs.ipv6_addrs[0].addr_s); > } > } > } > @@ -693,6 +735,7 @@ destroy_nat_entries(struct ovn_datapath *od) > return; > } > > + sset_destroy(&od->snat_ips); > for (size_t i = 0; i < od->nbr->n_nat; i++) { > destroy_lport_addresses(&od->nat_entries[i].ext_addrs); > } > @@ -8744,6 +8787,68 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports, > op, lflows, &match, &actions); > } > > + /* Drop IP traffic destined to router owned IPs. Part of it is dropped > + * in stage "lr_in_ip_input" but traffic that could have been unSNATed > + * but didn't match any existing session might still end up here. > + */ > + HMAP_FOR_EACH (op, key_node, ports) { > + if (!op->nbrp) { > + continue; > + } > + > + if (op->lrp_networks.n_ipv4_addrs) { > + ds_clear(&match); > + for (size_t i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) { > + if (!sset_find(&op->od->snat_ips, > + op->lrp_networks.ipv4_addrs[i].addr_s)) { > + continue; > + } > + ds_put_format(&match, "%s, ", > + op->lrp_networks.ipv4_addrs[i].addr_s); > + } > + > + if (ds_last(&match) != EOF) { > + ds_chomp(&match, ' '); > + ds_chomp(&match, ','); > + > + char *drop_match = xasprintf("ip4.dst == {%s}", > + ds_cstr(&match)); > + /* Drop traffic with IP.dest == router-ip. */ > + ovn_lflow_add_with_hint(lflows, op->od, > + S_ROUTER_IN_ARP_RESOLVE, 1, > + drop_match, "drop;", > + &op->nbrp->header_); > + free(drop_match); > + } > + } > + > + if (op->lrp_networks.n_ipv6_addrs) { > + ds_clear(&match); > + for (size_t i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) { > + if (!sset_find(&op->od->snat_ips, > + op->lrp_networks.ipv6_addrs[i].addr_s)) { > + continue; > + } > + ds_put_format(&match, "%s, ", > + op->lrp_networks.ipv6_addrs[i].addr_s); > + } > + > + if (ds_last(&match) != EOF) { > + ds_chomp(&match, ' '); > + ds_chomp(&match, ','); > + > + char *drop_match = xasprintf("ip6.dst == {%s}", > + ds_cstr(&match)); > + /* Drop traffic with IP.dest == router-ip. */ > + ovn_lflow_add_with_hint(lflows, op->od, > + S_ROUTER_IN_ARP_RESOLVE, 1, > + drop_match, "drop;", > + &op->nbrp->header_); > + free(drop_match); > + } > + } > + } > + > HMAP_FOR_EACH (od, key_node, datapaths) { > if (!od->nbr) { > continue; > @@ -9035,77 +9140,15 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports, > } > > /* A gateway router can have 4 SNAT IP addresses to force DNATed and > - * LBed traffic respectively to be SNATed. In addition, there can be > - * a number of SNAT rules in the NAT table. */ > - struct v46_ip *snat_ips = xmalloc(sizeof *snat_ips > - * (op->od->nbr->n_nat + 4)); > - size_t n_snat_ips = 0; > - struct lport_addresses snat_addrs; > - > - if (get_force_snat_ip(op->od, "dnat", &snat_addrs)) { > - if (snat_addrs.n_ipv4_addrs) { > - snat_ips[n_snat_ips].family = AF_INET; > - snat_ips[n_snat_ips++].ipv4 = snat_addrs.ipv4_addrs[0].addr; > - } > - if (snat_addrs.n_ipv6_addrs) { > - snat_ips[n_snat_ips].family = AF_INET6; > - snat_ips[n_snat_ips++].ipv6 = snat_addrs.ipv6_addrs[0].addr; > - } > - destroy_lport_addresses(&snat_addrs); > - } > - > - memset(&snat_addrs, 0, sizeof(snat_addrs)); > - if (get_force_snat_ip(op->od, "lb", &snat_addrs)) { > - if (snat_addrs.n_ipv4_addrs) { > - snat_ips[n_snat_ips].family = AF_INET; > - snat_ips[n_snat_ips++].ipv4 = snat_addrs.ipv4_addrs[0].addr; > - } > - if (snat_addrs.n_ipv6_addrs) { > - snat_ips[n_snat_ips].family = AF_INET6; > - snat_ips[n_snat_ips++].ipv6 = snat_addrs.ipv6_addrs[0].addr; > - } > - destroy_lport_addresses(&snat_addrs); > - } > - > - for (size_t i = 0; i < op->od->nbr->n_nat; i++) { > - struct ovn_nat *nat_entry = &op->od->nat_entries[i]; > - const struct nbrec_nat *nat = nat_entry->nb; > - > - /* Skip entries we failed to parse. */ > - if (!nat_entry_is_valid(nat_entry)) { > - continue; > - } > - > - if (!strcmp(nat->type, "snat")) { > - if (nat_entry_is_v6(nat_entry)) { > - struct in6_addr *ipv6 = > - &nat_entry->ext_addrs.ipv6_addrs[0].addr; > - > - snat_ips[n_snat_ips].family = AF_INET6; > - snat_ips[n_snat_ips++].ipv6 = *ipv6; > - } else { > - ovs_be32 ip = nat_entry->ext_addrs.ipv4_addrs[0].addr; > - snat_ips[n_snat_ips].family = AF_INET; > - snat_ips[n_snat_ips++].ipv4 = ip; > - } > - } > - } > - > + * LBed traffic respectively to be SNATed. In addition, there can be > + * a number of SNAT rules in the NAT table. > + * Skip all of them for drop flows. */ > ds_clear(&match); > ds_put_cstr(&match, "ip4.dst == {"); > bool has_drop_ips = false; > for (int i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) { > - bool snat_ip_is_router_ip = false; > - for (int j = 0; j < n_snat_ips; j++) { > - /* Packets to SNAT IPs should not be dropped. */ > - if (snat_ips[j].family == AF_INET > - && op->lrp_networks.ipv4_addrs[i].addr > - == snat_ips[j].ipv4) { > - snat_ip_is_router_ip = true; > - break; > - } > - } > - if (snat_ip_is_router_ip) { > + if (sset_find(&op->od->snat_ips, > + op->lrp_networks.ipv4_addrs[i].addr_s)) { > continue; > } > ds_put_format(&match, "%s, ", > @@ -9122,17 +9165,8 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports, > } > > for (int i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) { > - bool snat_ip_is_router_ip = false; > - for (int j = 0; j < n_snat_ips; j++) { > - /* Packets to SNAT IPs should not be dropped. */ > - if (snat_ips[j].family == AF_INET6 > - && !memcmp(&op->lrp_networks.ipv6_addrs[i].addr, > - &snat_ips[j].ipv6, sizeof snat_ips[j].ipv6)) { > - snat_ip_is_router_ip = true; > - break; > - } > - } > - if (snat_ip_is_router_ip) { > + if (sset_find(&op->od->snat_ips, > + op->lrp_networks.ipv6_addrs[i].addr_s)) { > continue; > } > ds_put_format(&match, "%s, ", > @@ -9151,8 +9185,6 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports, > &op->nbrp->header_); > } > > - free(snat_ips); > - > /* ARP/NS packets are taken care of per router. The only exception > * is on the l3dgw_port where we might need to use a different > * ETH address. > diff --git a/tests/ovn.at b/tests/ovn.at > index a6f1fb5..cb7e7cc 100644 > --- a/tests/ovn.at > +++ b/tests/ovn.at > @@ -21659,6 +21659,94 @@ OVS_WAIT_UNTIL([test x$(as hv1 ovn-appctl -t ovn-controller debug/status) = "xru > OVN_CLEANUP([hv1]) > AT_CLEANUP > > +# Test dropping traffic destined to router owned IPs. > +AT_SETUP([ovn -- gateway router drop traffic for own IPs]) > +ovn_start > + > +ovn-nbctl lr-add r1 -- set logical_router r1 options:chassis=hv1 > +ovn-nbctl ls-add s1 > + > +# Connnect r1 to s1. > +ovn-nbctl lrp-add r1 lrp-r1-s1 00:00:00:00:01:01 10.0.1.1/24 > +ovn-nbctl lsp-add s1 lsp-s1-r1 -- set Logical_Switch_Port lsp-s1-r1 type=router \ > + options:router-port=lrp-r1-s1 addresses=router > + > +# Create logical port p1 in s1 > +ovn-nbctl lsp-add s1 p1 \ > +-- lsp-set-addresses p1 "f0:00:00:00:01:02 10.0.1.2" > + > +# Create two hypervisor and create OVS ports corresponding to logical ports. > +net_add n1 > + > +sim_add hv1 > +as hv1 > +ovs-vsctl add-br br-phys > +ovn_attach n1 br-phys 192.168.0.1 > +ovs-vsctl -- add-port br-int hv1-vif1 -- \ > + set interface hv1-vif1 external-ids:iface-id=p1 \ > + options:tx_pcap=hv1/vif1-tx.pcap \ > + options:rxq_pcap=hv1/vif1-rx.pcap \ > + ofport-request=1 > + > +# Pre-populate the hypervisors' ARP tables so that we don't lose any > +# packets for ARP resolution (native tunneling doesn't queue packets > +# for ARP resolution). > +OVN_POPULATE_ARP > + > +ovn-nbctl --wait=hv sync > + > +sw_key=$(ovn-sbctl --bare --columns tunnel_key list datapath_binding r1) > + > +AT_CHECK([ovn-sbctl lflow-list | grep lr_in_arp_resolve | grep 10.0.1.1], [1], []) > + > +ip_to_hex() { > + printf "%02x%02x%02x%02x" "$@" > +} > + > +# Send ip packets from p1 to lrp-r1-s1 > +src_mac="f00000000102" > +dst_mac="000000000101" > +src_ip=`ip_to_hex 10 0 1 2` > +dst_ip=`ip_to_hex 10 0 1 1` > +packet=${dst_mac}${src_mac}08004500001c0000000040110000${src_ip}${dst_ip}0035111100080000 > +as hv1 ovs-appctl netdev-dummy/receive hv1-vif1 $packet > + > +# No packet-ins should reach ovn-controller. > +AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | grep "actions=controller" | grep -v n_packets=0 -c], [1], [dnl > +0 > +]) > + > +# The packet should have been dropped in the lr_in_ip_input stage. > +AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | grep -E "table=11, n_packets=1,.* priority=60,ip,metadata=0x${sw_key},nw_dst=10.0.1.1 actions=drop" -c], [0], [dnl > +1 > +]) > + > +# Use the router IP as SNAT IP. > +ovn-nbctl set logical_router r1 options:lb_force_snat_ip=10.0.1.1 > +ovn-nbctl --wait=hv sync > + > +# Send ip packets from p1 to lrp-r1-s1 > +src_mac="f00000000102" > +dst_mac="000000000101" > +src_ip=`ip_to_hex 10 0 1 2` > +dst_ip=`ip_to_hex 10 0 1 1` > +packet=${dst_mac}${src_mac}08004500001c0000000040110000${src_ip}${dst_ip}0035111100080000 > +as hv1 ovs-appctl netdev-dummy/receive hv1-vif1 $packet > + > +# Even after configuring a router owned IP for SNAT, no packet-ins should > +# reach ovn-controller. > +AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | grep "actions=controller" | grep -v n_packets=0 -c], [1], [dnl > +0 > +]) > + > +# The packet should've been dropped in the lr_in_arp_resolve stage. > +AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | grep -E "table=21, n_packets=1,.* priority=1,ip,metadata=0x${sw_key},nw_dst=10.0.1.1 actions=drop" -c], [0], [dnl > +1 > +]) > + > +OVN_CLEANUP([hv1]) > +AT_CLEANUP > + > AT_SETUP([ovn -- nb_cfg timestamp]) > ovn_start > > > _______________________________________________ > dev mailing list > d...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Acked-by: Han Zhou <hz...@ovn.org> _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev