On 9/22/20 8:17 AM, Numan Siddique wrote: > > > On Mon, Sep 21, 2020 at 12:08 PM Han Zhou <[email protected] > <mailto:[email protected]>> wrote: > > On Thu, Sep 17, 2020 at 5:51 AM Dumitru Ceara <[email protected] > <mailto:[email protected]>> 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 <[email protected] <mailto:[email protected]>> > > Reported-at: https://bugzilla.redhat.com/1876174 > > Signed-off-by: Dumitru Ceara <[email protected] > <mailto:[email protected]>> > > --- > > northd/ovn-northd.8.xml | 24 ++++++ > > northd/ovn-northd.c | 194 > +++++++++++++++++++++++++++-------------------- > > tests/ovn.at <http://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 <http://ovn.at> b/tests/ovn.at > <http://ovn.at> > > index a6f1fb5..cb7e7cc 100644 > > --- a/tests/ovn.at <http://ovn.at> > > +++ b/tests/ovn.at <http://ovn.at> > > @@ -21659,6 +21659,94 @@ OVS_WAIT_UNTIL([test x$(as hv1 ovn-appctl -t > ovn-controller debug/status) = "xru > > OVN_CLEANUP([hv1]) > > AT_CLEANUP > > > > +# Test dropping traffic destined to router owned IPs. > > +AT_SETUP([ovn -- gateway router drop traffic for own IPs]) > > +ovn_start > > + > > +ovn-nbctl lr-add r1 -- set logical_router r1 options:chassis=hv1 > > +ovn-nbctl ls-add s1 > > + > > +# Connnect r1 to s1. > > +ovn-nbctl lrp-add r1 lrp-r1-s1 00:00:00:00:01:01 10.0.1.1/24 > <http://10.0.1.1/24> > > +ovn-nbctl lsp-add s1 lsp-s1-r1 -- set Logical_Switch_Port lsp-s1-r1 > type=router \ > > + options:router-port=lrp-r1-s1 addresses=router > > + > > +# Create logical port p1 in s1 > > +ovn-nbctl lsp-add s1 p1 \ > > +-- lsp-set-addresses p1 "f0:00:00:00:01:02 10.0.1.2" > > + > > +# Create two hypervisor and create OVS ports corresponding to logical > ports. > > +net_add n1 > > + > > +sim_add hv1 > > +as hv1 > > +ovs-vsctl add-br br-phys > > +ovn_attach n1 br-phys 192.168.0.1 > > +ovs-vsctl -- add-port br-int hv1-vif1 -- \ > > + set interface hv1-vif1 external-ids:iface-id=p1 \ > > + options:tx_pcap=hv1/vif1-tx.pcap \ > > + options:rxq_pcap=hv1/vif1-rx.pcap \ > > + ofport-request=1 > > + > > +# Pre-populate the hypervisors' ARP tables so that we don't lose any > > +# packets for ARP resolution (native tunneling doesn't queue packets > > +# for ARP resolution). > > +OVN_POPULATE_ARP > > + > > +ovn-nbctl --wait=hv sync > > + > > +sw_key=$(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 > > [email protected] <mailto:[email protected]> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > Acked-by: Han Zhou <[email protected] <mailto:[email protected]>> > > > Thanks Dumitru and Han. I applied this patch to master and branch-20.09. > > The patch doesn't apply cleanly to branch-20.06. There were many > conflicts and I didn't try resolving myself. > Dumitru - please submit the backport patches to branch-20.06 (and > branch-20.03 if you would like). > > Thanks > Numan >
Thanks! While this is a bug fix I don't think it's critical to have it on branch-20.06/branch-20.03. Unless someone requires it on older releases too I'd skip sending a backport patch for it. Regards, Dumitru _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
