/* * Copyright (c) 2015 Nicira, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_NF_NAT_NEEDED #include #include #include #endif #include "datapath.h" #include "conntrack.h" #include "flow.h" #include "flow_netlink.h" struct ovs_ct_len_tbl { int maxlen; int minlen; }; /* Metadata mark for masked write to conntrack mark */ struct md_mark { u32 value; u32 mask; }; /* Metadata label for masked write to conntrack label. */ struct md_labels { struct ovs_key_ct_labels value; struct ovs_key_ct_labels mask; }; enum ovs_ct_nat { OVS_CT_NAT = 1 << 0, /* NAT for committed connections only. */ OVS_CT_SRC_NAT = 1 << 1, /* Source NAT for NEW connections. */ OVS_CT_DST_NAT = 1 << 2, /* Destination NAT for NEW connections. */ }; /* Conntrack action context for execution. */ struct ovs_conntrack_info { struct nf_conntrack_helper *helper; struct nf_conntrack_zone zone; struct nf_conn *ct; u8 commit : 1; u8 nat : 3; /* enum ovs_ct_nat */ u16 family; struct md_mark mark; struct md_labels labels; #ifdef CONFIG_NF_NAT_NEEDED struct nf_nat_range range; /* Only present for SRC NAT and DST NAT. */ #endif }; static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info); static u16 key_to_nfproto(const struct sw_flow_key *key) { switch (ntohs(key->eth.type)) { case ETH_P_IP: return NFPROTO_IPV4; case ETH_P_IPV6: return NFPROTO_IPV6; default: return NFPROTO_UNSPEC; } } /* Map SKB connection state into the values used by flow definition. */ static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo) { u8 ct_state = OVS_CS_F_TRACKED; switch (ctinfo) { case IP_CT_ESTABLISHED_REPLY: case IP_CT_RELATED_REPLY: ct_state |= OVS_CS_F_REPLY_DIR; break; default: break; } switch (ctinfo) { case IP_CT_ESTABLISHED: case IP_CT_ESTABLISHED_REPLY: ct_state |= OVS_CS_F_ESTABLISHED; break; case IP_CT_RELATED: case IP_CT_RELATED_REPLY: ct_state |= OVS_CS_F_RELATED; break; case IP_CT_NEW: ct_state |= OVS_CS_F_NEW; break; default: break; } return ct_state; } static u32 ovs_ct_get_mark(const struct nf_conn *ct) { #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) return ct ? ct->mark : 0; #else return 0; #endif } static void ovs_ct_get_labels(const struct nf_conn *ct, struct ovs_key_ct_labels *labels) { struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL; if (cl) { size_t len = sizeof(cl->bits); if (len > OVS_CT_LABELS_LEN) len = OVS_CT_LABELS_LEN; else if (len < OVS_CT_LABELS_LEN) memset(labels, 0, OVS_CT_LABELS_LEN); memcpy(labels, cl->bits, len); } else { memset(labels, 0, OVS_CT_LABELS_LEN); } } static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state, const struct nf_conntrack_zone *zone, const struct nf_conn *ct) { key->ct.state = state; key->ct.zone = zone->id; key->ct.mark = ovs_ct_get_mark(ct); ovs_ct_get_labels(ct, &key->ct.labels); } /* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has * previously sent the packet to conntrack via the ct action. If * 'keep_nat_flags' is true, the existing NAT flags retained, else they are * initialized from the connection status. */ static void ovs_ct_update_key(const struct sk_buff *skb, const struct ovs_conntrack_info *info, struct sw_flow_key *key, bool post_ct, bool keep_nat_flags) { const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; enum ip_conntrack_info ctinfo; struct nf_conn *ct; u8 state = 0; ct = nf_ct_get(skb, &ctinfo); if (ct) { state = ovs_ct_get_state(ctinfo); /* All unconfirmed entries are NEW connections. */ if (!nf_ct_is_confirmed(ct)) state |= OVS_CS_F_NEW; /* OVS persists the related flag for the duration of the * connection. */ if (ct->master) state |= OVS_CS_F_RELATED; if (keep_nat_flags) { state |= key->ct.state & OVS_CS_F_NAT_MASK; } else { if (ct->status & IPS_SRC_NAT) state |= OVS_CS_F_SRC_NAT; if (ct->status & IPS_DST_NAT) state |= OVS_CS_F_DST_NAT; } zone = nf_ct_zone(ct); } else if (post_ct) { state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID; if (info) zone = &info->zone; } __ovs_ct_update_key(key, state, zone, ct); } /* This is called to initialize CT key fields possibly coming in from the local * stack. */ void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key) { ovs_ct_update_key(skb, NULL, key, false, false); } int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb) { if (nla_put_u32(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && nla_put(skb, OVS_KEY_ATTR_CT_LABELS, sizeof(key->ct.labels), &key->ct.labels)) return -EMSGSIZE; return 0; } static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key, u32 ct_mark, u32 mask) { #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) enum ip_conntrack_info ctinfo; struct nf_conn *ct; u32 new_mark; /* The connection could be invalid, in which case set_mark is no-op. */ ct = nf_ct_get(skb, &ctinfo); if (!ct) return 0; new_mark = ct_mark | (ct->mark & ~(mask)); if (ct->mark != new_mark) { ct->mark = new_mark; nf_conntrack_event_cache(IPCT_MARK, ct); key->ct.mark = new_mark; } return 0; #else return -ENOTSUPP; #endif } static int ovs_ct_set_labels(struct sk_buff *skb, struct sw_flow_key *key, const struct ovs_key_ct_labels *labels, const struct ovs_key_ct_labels *mask) { enum ip_conntrack_info ctinfo; struct nf_conn_labels *cl; struct nf_conn *ct; int err; /* The connection could be invalid, in which case set_label is no-op.*/ ct = nf_ct_get(skb, &ctinfo); if (!ct) return 0; cl = nf_ct_labels_find(ct); if (!cl) { nf_ct_labels_ext_add(ct); cl = nf_ct_labels_find(ct); } if (!cl || sizeof(cl->bits) < OVS_CT_LABELS_LEN) return -ENOSPC; err = nf_connlabels_replace(ct, (u32 *)labels, (u32 *)mask, OVS_CT_LABELS_LEN / sizeof(u32)); if (err) return err; ovs_ct_get_labels(ct, &key->ct.labels); return 0; } /* 'skb' should already be pulled to nh_ofs. */ static int ovs_ct_helper(struct sk_buff *skb, u16 proto) { const struct nf_conntrack_helper *helper; const struct nf_conn_help *help; enum ip_conntrack_info ctinfo; unsigned int protoff; struct nf_conn *ct; int err; ct = nf_ct_get(skb, &ctinfo); if (!ct || ctinfo == IP_CT_RELATED_REPLY) return NF_ACCEPT; help = nfct_help(ct); if (!help) return NF_ACCEPT; helper = rcu_dereference(help->helper); if (!helper) return NF_ACCEPT; switch (proto) { case NFPROTO_IPV4: protoff = ip_hdrlen(skb); break; case NFPROTO_IPV6: { u8 nexthdr = ipv6_hdr(skb)->nexthdr; __be16 frag_off; int ofs; ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); if (ofs < 0 || (frag_off & htons(~0x7)) != 0) { pr_debug("proto header not found\n"); return NF_ACCEPT; } protoff = ofs; break; } default: WARN_ONCE(1, "helper invoked on non-IP family!"); return NF_DROP; } err = helper->help(skb, protoff, ct, ctinfo); if (err != NF_ACCEPT) return err; /* Adjust seqs after helper. This is needed due to some helpers (e.g., * FTP with NAT) adusting the TCP payload size when mangling IP * addresses and/or port numbers in the text-based control connection. */ if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && !nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) return NF_DROP; return NF_ACCEPT; } /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero * value if 'skb' is freed. */ static int handle_fragments(struct net *net, struct sw_flow_key *key, u16 zone, struct sk_buff *skb) { struct ovs_skb_cb ovs_cb = *OVS_CB(skb); int err; if (key->eth.type == htons(ETH_P_IP)) { enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone; memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); err = ip_defrag(net, skb, user); if (err) return err; ovs_cb.mru = IPCB(skb)->frag_max_size; #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) } else if (key->eth.type == htons(ETH_P_IPV6)) { enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone; memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); err = nf_ct_frag6_gather(net, skb, user); if (err) { if (err != -EINPROGRESS) kfree_skb(skb); return err; } key->ip.proto = ipv6_hdr(skb)->nexthdr; ovs_cb.mru = IP6CB(skb)->frag_max_size; #endif } else { kfree_skb(skb); return -EPFNOSUPPORT; } key->ip.frag = OVS_FRAG_TYPE_NONE; skb_clear_hash(skb); skb->ignore_df = 1; *OVS_CB(skb) = ovs_cb; return 0; } static struct nf_conntrack_expect * ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone, u16 proto, const struct sk_buff *skb) { struct nf_conntrack_tuple tuple; struct nf_conntrack_expect *exp; if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, &tuple)) return NULL; exp = __nf_ct_expect_find(net, zone, &tuple); if (exp) { struct nf_conntrack_tuple_hash *h; /* Delete existing conntrack entry, if it clashes with the * expectation. This can happen since conntrack ALGs do not * check for clashes between (new) expectations and existing * conntrack entries. nf_conntrack_in() will check the * expectations only if a conntrack entry can not be found, * which can lead to OVS finding the expectation (here) in the * init direction, but which will not be removed by the * nf_conntrack_in() call, if a matching conntrack entry is * found instead. In this case all init direction packets * would be reported as new related packets, while reply * direction packets would be reported as un-related * established packets. */ h = nf_conntrack_find_get(net, zone, &tuple); if (h) { struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); nf_ct_delete(ct, 0, 0); nf_conntrack_put(&ct->ct_general); } } return exp; } /* This replicates logic from nf_conntrack_core.c that is not exported. */ static enum ip_conntrack_info ovs_ct_get_info(const struct nf_conntrack_tuple_hash *h) { const struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) return IP_CT_ESTABLISHED_REPLY; /* Once we've had two way comms, always ESTABLISHED. */ if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) return IP_CT_ESTABLISHED; if (test_bit(IPS_EXPECTED_BIT, &ct->status)) return IP_CT_RELATED; return IP_CT_NEW; } /* Find an existing connection which this packet belongs to without * re-attributing statistics or modifying the connection state. This allows an * skb->nfct lost due to an upcall to be recovered during actions execution. * * Must be called with rcu_read_lock. * * On success, populates skb->nfct and skb->nfctinfo, and returns the * connection. Returns NULL if there is no existing entry. */ static struct nf_conn * ovs_ct_find_existing(struct net *net, const struct nf_conntrack_zone *zone, u8 l3num, struct sk_buff *skb) { struct nf_conntrack_l3proto *l3proto; struct nf_conntrack_l4proto *l4proto; struct nf_conntrack_tuple tuple; struct nf_conntrack_tuple_hash *h; struct nf_conn *ct; unsigned int dataoff; u8 protonum; l3proto = __nf_ct_l3proto_find(l3num); if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff, &protonum) <= 0) { pr_debug("ovs_ct_find_existing: Can't get protonum\n"); return NULL; } l4proto = __nf_ct_l4proto_find(l3num, protonum); if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num, protonum, net, &tuple, l3proto, l4proto)) { pr_debug("ovs_ct_find_existing: Can't get tuple\n"); return NULL; } /* look for tuple match */ h = nf_conntrack_find_get(net, zone, &tuple); if (!h) return NULL; /* Not found. */ ct = nf_ct_tuplehash_to_ctrack(h); skb->nfct = &ct->ct_general; skb->nfctinfo = ovs_ct_get_info(h); return ct; } /* Determine whether skb->nfct is equal to the result of conntrack lookup. */ static bool skb_nfct_cached(struct net *net, const struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb) { enum ip_conntrack_info ctinfo; struct nf_conn *ct; ct = nf_ct_get(skb, &ctinfo); /* If no ct, check if we have evidence that an existing conntrack entry * might be found for this skb. This happens when we lose a skb->nfct * due to an upcall. If the connection was not confirmed, it is not * cached and needs to be run through conntrack again. */ if (!ct && key->ct.state & OVS_CS_F_TRACKED && !(key->ct.state & OVS_CS_F_INVALID) && key->ct.zone == info->zone.id) ct = ovs_ct_find_existing(net, &info->zone, info->family, skb); if (!ct) return false; if (!net_eq(net, read_pnet(&ct->ct_net))) return false; if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct))) return false; if (info->helper) { struct nf_conn_help *help; help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER); if (help && rcu_access_pointer(help->helper) != info->helper) return false; } return true; } #ifdef CONFIG_NF_NAT_NEEDED /* Modelled after nf_nat_ipv[46]_fn(). * range is only used for new, uninitialized NAT state. * Returns either NF_ACCEPT or NF_DROP. */ static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo, const struct nf_nat_range *range, enum nf_nat_manip_type maniptype) { int hooknum, nh_off, err = NF_ACCEPT; nh_off = skb_network_offset(skb); skb_pull_rcsum(skb, nh_off); /* See HOOK2MANIP(). */ if (maniptype == NF_NAT_MANIP_SRC) hooknum = NF_INET_LOCAL_IN; /* Source NAT */ else hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */ switch (ctinfo) { case IP_CT_RELATED: case IP_CT_RELATED_REPLY: if (IS_ENABLED(CONFIG_NF_NAT_IPV4) && skb->protocol == htons(ETH_P_IP) && ip_hdr(skb)->protocol == IPPROTO_ICMP) { if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo, hooknum)) err = NF_DROP; goto push; } else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { __be16 frag_off; u8 nexthdr = ipv6_hdr(skb)->nexthdr; int hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) { if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo, hooknum, hdrlen)) err = NF_DROP; goto push; } } /* Non-ICMP, fall thru to initialize if needed. */ case IP_CT_NEW: /* Seen it before? This can happen for loopback, retrans, * or local packets. */ if (!nf_nat_initialized(ct, maniptype)) { /* Initialize according to the NAT action. */ err = (range && range->flags & NF_NAT_RANGE_MAP_IPS) /* Action is set up to establish a new * mapping. */ ? nf_nat_setup_info(ct, range, maniptype) : nf_nat_alloc_null_binding(ct, hooknum); if (err != NF_ACCEPT) goto push; } break; case IP_CT_ESTABLISHED: case IP_CT_ESTABLISHED_REPLY: break; default: err = NF_DROP; goto push; } err = nf_nat_packet(ct, ctinfo, hooknum, skb); push: skb_push(skb, nh_off); skb_postpush_rcsum(skb, skb->data, nh_off); return err; } static void ovs_nat_update_key(struct sw_flow_key *key, const struct sk_buff *skb, enum nf_nat_manip_type maniptype) { if (maniptype == NF_NAT_MANIP_SRC) { __be16 src; key->ct.state |= OVS_CS_F_SRC_NAT; if (key->eth.type == htons(ETH_P_IP)) key->ipv4.addr.src = ip_hdr(skb)->saddr; else if (key->eth.type == htons(ETH_P_IPV6)) memcpy(&key->ipv6.addr.src, &ipv6_hdr(skb)->saddr, sizeof(key->ipv6.addr.src)); else return; if (key->ip.proto == IPPROTO_UDP) src = udp_hdr(skb)->source; else if (key->ip.proto == IPPROTO_TCP) src = tcp_hdr(skb)->source; else if (key->ip.proto == IPPROTO_SCTP) src = sctp_hdr(skb)->source; else return; key->tp.src = src; } else { __be16 dst; key->ct.state |= OVS_CS_F_DST_NAT; if (key->eth.type == htons(ETH_P_IP)) key->ipv4.addr.dst = ip_hdr(skb)->daddr; else if (key->eth.type == htons(ETH_P_IPV6)) memcpy(&key->ipv6.addr.dst, &ipv6_hdr(skb)->daddr, sizeof(key->ipv6.addr.dst)); else return; if (key->ip.proto == IPPROTO_UDP) dst = udp_hdr(skb)->dest; else if (key->ip.proto == IPPROTO_TCP) dst = tcp_hdr(skb)->dest; else if (key->ip.proto == IPPROTO_SCTP) dst = sctp_hdr(skb)->dest; else return; key->tp.dst = dst; } } /* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { enum nf_nat_manip_type maniptype; int err; if (nf_ct_is_untracked(ct)) { /* A NAT action may only be performed on tracked packets. */ return NF_ACCEPT; } /* Add NAT extension if not confirmed yet. */ if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct)) return NF_ACCEPT; /* Can't NAT. */ /* Determine NAT type. * Check if the NAT type can be deduced from the tracked connection. * Make sure new expected connections (IP_CT_RELATED) are NATted only * when committing. */ if (info->nat & OVS_CT_NAT && ctinfo != IP_CT_NEW && ct->status & IPS_NAT_MASK && (ctinfo != IP_CT_RELATED || info->commit)) { /* NAT an established or related connection like before. */ if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) /* This is the REPLY direction for a connection * for which NAT was applied in the forward * direction. Do the reverse NAT. */ maniptype = ct->status & IPS_SRC_NAT ? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC; else maniptype = ct->status & IPS_SRC_NAT ? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST; } else if (info->nat & OVS_CT_SRC_NAT) { maniptype = NF_NAT_MANIP_SRC; } else if (info->nat & OVS_CT_DST_NAT) { maniptype = NF_NAT_MANIP_DST; } else { return NF_ACCEPT; /* Connection is not NATed. */ } err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype); /* Mark NAT done if successful and update the flow key. */ if (err == NF_ACCEPT) ovs_nat_update_key(key, skb, maniptype); return err; } #else /* !CONFIG_NF_NAT_NEEDED */ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { return NF_ACCEPT; } #endif /* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if * not done already. Update key with new CT state after passing the packet * through conntrack. * Note that if the packet is deemed invalid by conntrack, skb->nfct will be * set to NULL and 0 will be returned. */ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb) { /* If we are recirculating packets to match on conntrack fields and * committing with a separate conntrack action, then we don't need to * actually run the packet through conntrack twice unless it's for a * different zone. */ bool cached = skb_nfct_cached(net, key, info, skb); enum ip_conntrack_info ctinfo; struct nf_conn *ct; if (!cached) { struct nf_conn *tmpl = info->ct; int err; /* Associate skb with specified zone. */ if (tmpl) { if (skb->nfct) nf_conntrack_put(skb->nfct); nf_conntrack_get(&tmpl->ct_general); skb->nfct = &tmpl->ct_general; skb->nfctinfo = IP_CT_NEW; } /* Repeat if requested, see nf_iterate(). */ do { err = nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING, skb); } while (err == NF_REPEAT); if (err != NF_ACCEPT) return -ENOENT; /* Clear CT state NAT flags to mark that we have not yet done * NAT after the nf_conntrack_in() call. We can actually clear * the whole state, as it will be re-initialized below. */ key->ct.state = 0; /* Update the key, but keep the NAT flags. */ ovs_ct_update_key(skb, info, key, true, true); } ct = nf_ct_get(skb, &ctinfo); if (ct) { /* Packets starting a new connection must be NATted before the * helper, so that the helper knows about the NAT. We enforce * this by delaying both NAT and helper calls for unconfirmed * connections until the committing CT action. For later * packets NAT and Helper may be called in either order. * * NAT will be done only if the CT action has NAT, and only * once per packet (per zone), as guarded by the NAT bits in * the key->ct.state. */ if (info->nat && !(key->ct.state & OVS_CS_F_NAT_MASK) && (nf_ct_is_confirmed(ct) || info->commit) && ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) { return -EINVAL; } /* Userspace may decide to perform a ct lookup without a helper * specified followed by a (recirculate and) commit with one. * Therefore, for unconfirmed connections which we will commit, * we need to attach the helper here. */ if (!nf_ct_is_confirmed(ct) && info->commit && info->helper && !nfct_help(ct)) { int err = __nf_ct_try_assign_helper(ct, info->ct, GFP_ATOMIC); if (err) return err; } /* Call the helper only if: * - nf_conntrack_in() was executed above ("!cached") for a * confirmed connection, or * - When committing an unconfirmed connection. */ if ((nf_ct_is_confirmed(ct) ? !cached : info->commit) && ovs_ct_helper(skb, info->family) != NF_ACCEPT) { return -EINVAL; } } return 0; } /* Lookup connection and read fields into key. */ static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb) { struct nf_conntrack_expect *exp; /* If we pass an expected packet through nf_conntrack_in() the * expectation is typically removed, but the packet could still be * lost in upcall processing. To prevent this from happening we * perform an explicit expectation lookup. Expected connections are * always new, and will be passed through conntrack only when they are * committed, as it is OK to remove the expectation at that time. */ exp = ovs_ct_expect_find(net, &info->zone, info->family, skb); if (exp) { u8 state; /* NOTE: New connections are NATted and Helped only when * committed, so we are not calling into NAT here. */ state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED; __ovs_ct_update_key(key, state, &info->zone, exp->master); } else { struct nf_conn *ct; int err; err = __ovs_ct_lookup(net, key, info, skb); if (err) return err; ct = (struct nf_conn *)skb->nfct; if (ct) nf_ct_deliver_cached_events(ct); } return 0; } static bool labels_nonzero(const struct ovs_key_ct_labels *labels) { size_t i; for (i = 0; i < sizeof(*labels); i++) if (labels->ct_labels[i]) return true; return false; } /* Lookup connection and confirm if unconfirmed. */ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key, const struct ovs_conntrack_info *info, struct sk_buff *skb) { int err; err = __ovs_ct_lookup(net, key, info, skb); if (err) return err; /* Apply changes before confirming the connection so that the initial * conntrack NEW netlink event carries the values given in the CT * action. */ if (info->mark.mask) { err = ovs_ct_set_mark(skb, key, info->mark.value, info->mark.mask); if (err) return err; } if (labels_nonzero(&info->labels.mask)) { err = ovs_ct_set_labels(skb, key, &info->labels.value, &info->labels.mask); if (err) return err; } /* This will take care of sending queued events even if the connection * is already confirmed. */ if (nf_conntrack_confirm(skb) != NF_ACCEPT) return -EINVAL; return 0; } /* Trim the skb to the length specified by the IP/IPv6 header, * removing any trailing lower-layer padding. This prepares the skb * for higher-layer processing that assumes skb->len excludes padding * (such as nf_ip_checksum). The caller needs to pull the skb to the * network header, and ensure ip_hdr/ipv6_hdr points to valid data. */ static int ovs_skb_network_trim(struct sk_buff *skb) { unsigned int len; int err; switch (skb->protocol) { case htons(ETH_P_IP): len = ntohs(ip_hdr(skb)->tot_len); break; case htons(ETH_P_IPV6): len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len); break; default: len = skb->len; } err = pskb_trim_rcsum(skb, len); if (err) kfree_skb(skb); return err; } /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero * value if 'skb' is freed. */ int ovs_ct_execute(struct net *net, struct sk_buff *skb, struct sw_flow_key *key, const struct ovs_conntrack_info *info) { int nh_ofs; int err; /* The conntrack module expects to be working at L3. */ nh_ofs = skb_network_offset(skb); skb_pull_rcsum(skb, nh_ofs); err = ovs_skb_network_trim(skb); if (err) return err; if (key->ip.frag != OVS_FRAG_TYPE_NONE) { err = handle_fragments(net, key, info->zone.id, skb); if (err) return err; } if (info->commit) err = ovs_ct_commit(net, key, info, skb); else err = ovs_ct_lookup(net, key, info, skb); skb_push(skb, nh_ofs); skb_postpush_rcsum(skb, skb->data, nh_ofs); if (err) kfree_skb(skb); return err; } static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name, const struct sw_flow_key *key, bool log) { struct nf_conntrack_helper *helper; struct nf_conn_help *help; helper = nf_conntrack_helper_try_module_get(name, info->family, key->ip.proto); if (!helper) { OVS_NLERR(log, "Unknown helper \"%s\"", name); return -EINVAL; } help = nf_ct_helper_ext_add(info->ct, helper, GFP_KERNEL); if (!help) { module_put(helper->me); return -ENOMEM; } rcu_assign_pointer(help->helper, helper); info->helper = helper; return 0; } #ifdef CONFIG_NF_NAT_NEEDED static int parse_nat(const struct nlattr *attr, struct ovs_conntrack_info *info, bool log) { struct nlattr *a; int rem; bool have_ip_max = false; bool have_proto_max = false; bool ip_vers = (info->family == NFPROTO_IPV6); nla_for_each_nested(a, attr, rem) { static const int ovs_nat_attr_lens[OVS_NAT_ATTR_MAX + 1][2] = { [OVS_NAT_ATTR_SRC] = {0, 0}, [OVS_NAT_ATTR_DST] = {0, 0}, [OVS_NAT_ATTR_IP_MIN] = {sizeof(struct in_addr), sizeof(struct in6_addr)}, [OVS_NAT_ATTR_IP_MAX] = {sizeof(struct in_addr), sizeof(struct in6_addr)}, [OVS_NAT_ATTR_PROTO_MIN] = {sizeof(u16), sizeof(u16)}, [OVS_NAT_ATTR_PROTO_MAX] = {sizeof(u16), sizeof(u16)}, [OVS_NAT_ATTR_PERSISTENT] = {0, 0}, [OVS_NAT_ATTR_PROTO_HASH] = {0, 0}, [OVS_NAT_ATTR_PROTO_RANDOM] = {0, 0}, }; int type = nla_type(a); if (type > OVS_NAT_ATTR_MAX) { OVS_NLERR(log, "Unknown NAT attribute (type=%d, max=%d).\n", type, OVS_NAT_ATTR_MAX); return -EINVAL; } if (nla_len(a) != ovs_nat_attr_lens[type][ip_vers]) { OVS_NLERR(log, "NAT attribute type %d has unexpected length (%d != %d).\n", type, nla_len(a), ovs_nat_attr_lens[type][ip_vers]); return -EINVAL; } switch (type) { case OVS_NAT_ATTR_SRC: case OVS_NAT_ATTR_DST: if (info->nat) { OVS_NLERR(log, "Only one type of NAT may be specified.\n" ); return -ERANGE; } info->nat |= OVS_CT_NAT; info->nat |= ((type == OVS_NAT_ATTR_SRC) ? OVS_CT_SRC_NAT : OVS_CT_DST_NAT); break; case OVS_NAT_ATTR_IP_MIN: nla_memcpy(&info->range.min_addr, a, sizeof(info->range.min_addr)); info->range.flags |= NF_NAT_RANGE_MAP_IPS; break; case OVS_NAT_ATTR_IP_MAX: have_ip_max = true; nla_memcpy(&info->range.max_addr, a, sizeof(info->range.max_addr)); info->range.flags |= NF_NAT_RANGE_MAP_IPS; break; case OVS_NAT_ATTR_PROTO_MIN: info->range.min_proto.all = htons(nla_get_u16(a)); info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; break; case OVS_NAT_ATTR_PROTO_MAX: have_proto_max = true; info->range.max_proto.all = htons(nla_get_u16(a)); info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; break; case OVS_NAT_ATTR_PERSISTENT: info->range.flags |= NF_NAT_RANGE_PERSISTENT; break; case OVS_NAT_ATTR_PROTO_HASH: info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM; break; case OVS_NAT_ATTR_PROTO_RANDOM: info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY; break; default: OVS_NLERR(log, "Unknown nat attribute (%d).\n", type); return -EINVAL; } } if (rem > 0) { OVS_NLERR(log, "NAT attribute has %d unknown bytes.\n", rem); return -EINVAL; } if (!info->nat) { /* Do not allow flags if no type is given. */ if (info->range.flags) { OVS_NLERR(log, "NAT flags may be given only when NAT range (SRC or DST) is also specified.\n" ); return -EINVAL; } info->nat = OVS_CT_NAT; /* NAT existing connections. */ } else if (!info->commit) { OVS_NLERR(log, "NAT attributes may be specified only when CT COMMIT flag is also specified.\n" ); return -EINVAL; } /* Allow missing IP_MAX. */ if (info->range.flags & NF_NAT_RANGE_MAP_IPS && !have_ip_max) { memcpy(&info->range.max_addr, &info->range.min_addr, sizeof(info->range.max_addr)); } /* Allow missing PROTO_MAX. */ if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED && !have_proto_max) { info->range.max_proto.all = info->range.min_proto.all; } return 0; } #endif static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = { [OVS_CT_ATTR_COMMIT] = { .minlen = 0, .maxlen = 0 }, [OVS_CT_ATTR_ZONE] = { .minlen = sizeof(u16), .maxlen = sizeof(u16) }, [OVS_CT_ATTR_MARK] = { .minlen = sizeof(struct md_mark), .maxlen = sizeof(struct md_mark) }, [OVS_CT_ATTR_LABELS] = { .minlen = sizeof(struct md_labels), .maxlen = sizeof(struct md_labels) }, [OVS_CT_ATTR_HELPER] = { .minlen = 1, .maxlen = NF_CT_HELPER_NAME_LEN }, #ifdef CONFIG_NF_NAT_NEEDED /* NAT length is checked when parsing the nested attributes. */ [OVS_CT_ATTR_NAT] = { .minlen = 0, .maxlen = INT_MAX }, #endif }; static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info, const char **helper, bool log) { struct nlattr *a; int rem; nla_for_each_nested(a, attr, rem) { int type = nla_type(a); int maxlen; int minlen; if (type > OVS_CT_ATTR_MAX) { OVS_NLERR(log, "Unknown conntrack attr (type=%d, max=%d)", type, OVS_CT_ATTR_MAX); return -EINVAL; } maxlen = ovs_ct_attr_lens[type].maxlen; minlen = ovs_ct_attr_lens[type].minlen; if (nla_len(a) < minlen || nla_len(a) > maxlen) { OVS_NLERR(log, "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)", type, nla_len(a), maxlen); return -EINVAL; } switch (type) { case OVS_CT_ATTR_COMMIT: info->commit = true; break; #ifdef CONFIG_NF_CONNTRACK_ZONES case OVS_CT_ATTR_ZONE: info->zone.id = nla_get_u16(a); break; #endif #ifdef CONFIG_NF_CONNTRACK_MARK case OVS_CT_ATTR_MARK: { struct md_mark *mark = nla_data(a); if (!mark->mask) { OVS_NLERR(log, "ct_mark mask cannot be 0"); return -EINVAL; } info->mark = *mark; break; } #endif #ifdef CONFIG_NF_CONNTRACK_LABELS case OVS_CT_ATTR_LABELS: { struct md_labels *labels = nla_data(a); if (!labels_nonzero(&labels->mask)) { OVS_NLERR(log, "ct_labels mask cannot be 0"); return -EINVAL; } info->labels = *labels; break; } #endif case OVS_CT_ATTR_HELPER: *helper = nla_data(a); if (!memchr(*helper, '\0', nla_len(a))) { OVS_NLERR(log, "Invalid conntrack helper"); return -EINVAL; } break; #ifdef CONFIG_NF_NAT_NEEDED case OVS_CT_ATTR_NAT: { int err = parse_nat(a, info, log); if (err) return err; break; } #endif default: OVS_NLERR(log, "Unknown conntrack attr (%d)", type); return -EINVAL; } } #ifdef CONFIG_NF_CONNTRACK_MARK if (!info->commit && info->mark.mask) { OVS_NLERR(log, "Setting conntrack mark requires 'commit' flag."); return -EINVAL; } #endif #ifdef CONFIG_NF_CONNTRACK_LABELS if (!info->commit && labels_nonzero(&info->labels.mask)) { OVS_NLERR(log, "Setting conntrack labels requires 'commit' flag."); return -EINVAL; } #endif if (rem > 0) { OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem); return -EINVAL; } return 0; } bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr) { if (attr == OVS_KEY_ATTR_CT_STATE) return true; if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && attr == OVS_KEY_ATTR_CT_ZONE) return true; if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && attr == OVS_KEY_ATTR_CT_MARK) return true; if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && attr == OVS_KEY_ATTR_CT_LABELS) { struct ovs_net *ovs_net = net_generic(net, ovs_net_id); return ovs_net->xt_label; } return false; } int ovs_ct_copy_action(struct net *net, const struct nlattr *attr, const struct sw_flow_key *key, struct sw_flow_actions **sfa, bool log) { struct ovs_conntrack_info ct_info; const char *helper = NULL; u16 family; int err; family = key_to_nfproto(key); if (family == NFPROTO_UNSPEC) { OVS_NLERR(log, "ct family unspecified"); return -EINVAL; } memset(&ct_info, 0, sizeof(ct_info)); ct_info.family = family; nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID, NF_CT_DEFAULT_ZONE_DIR, 0); err = parse_ct(attr, &ct_info, &helper, log); if (err) return err; /* Set up template for tracking connections in specific zones. */ ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL); if (!ct_info.ct) { OVS_NLERR(log, "Failed to allocate conntrack template"); return -ENOMEM; } __set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status); nf_conntrack_get(&ct_info.ct->ct_general); if (helper) { err = ovs_ct_add_helper(&ct_info, helper, key, log); if (err) goto err_free_ct; } err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info, sizeof(ct_info), log); if (err) goto err_free_ct; return 0; err_free_ct: __ovs_ct_free_action(&ct_info); return err; } #ifdef CONFIG_NF_NAT_NEEDED static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info, struct sk_buff *skb) { struct nlattr *start; start = nla_nest_start(skb, OVS_CT_ATTR_NAT); if (!start) return false; if (info->nat & OVS_CT_SRC_NAT) { if (nla_put_flag(skb, OVS_NAT_ATTR_SRC)) return false; } else if (info->nat & OVS_CT_DST_NAT) { if (nla_put_flag(skb, OVS_NAT_ATTR_DST)) return false; } else { goto out; } if (info->range.flags & NF_NAT_RANGE_MAP_IPS) { if (IS_ENABLED(CONFIG_NF_NAT_IPV4) && info->family == NFPROTO_IPV4) { if (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MIN, info->range.min_addr.ip) || (info->range.max_addr.ip != info->range.min_addr.ip && (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MAX, info->range.max_addr.ip)))) return false; } else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) && info->family == NFPROTO_IPV6) { if (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MIN, &info->range.min_addr.in6) || (memcmp(&info->range.max_addr.in6, &info->range.min_addr.in6, sizeof(info->range.max_addr.in6)) && (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MAX, &info->range.max_addr.in6)))) return false; } else { return false; } } if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED && (nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MIN, ntohs(info->range.min_proto.all)) || (info->range.max_proto.all != info->range.min_proto.all && nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MAX, ntohs(info->range.max_proto.all))))) return false; if (info->range.flags & NF_NAT_RANGE_PERSISTENT && nla_put_flag(skb, OVS_NAT_ATTR_PERSISTENT)) return false; if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM && nla_put_flag(skb, OVS_NAT_ATTR_PROTO_HASH)) return false; if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY && nla_put_flag(skb, OVS_NAT_ATTR_PROTO_RANDOM)) return false; out: nla_nest_end(skb, start); return true; } #endif int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info, struct sk_buff *skb) { struct nlattr *start; start = nla_nest_start(skb, OVS_ACTION_ATTR_CT); if (!start) return -EMSGSIZE; if (ct_info->commit && nla_put_flag(skb, OVS_CT_ATTR_COMMIT)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask && nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark), &ct_info->mark)) return -EMSGSIZE; if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && labels_nonzero(&ct_info->labels.mask) && nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels), &ct_info->labels)) return -EMSGSIZE; if (ct_info->helper) { if (nla_put_string(skb, OVS_CT_ATTR_HELPER, ct_info->helper->name)) return -EMSGSIZE; } #ifdef CONFIG_NF_NAT_NEEDED if (ct_info->nat && !ovs_ct_nat_to_attr(ct_info, skb)) return -EMSGSIZE; #endif nla_nest_end(skb, start); return 0; } void ovs_ct_free_action(const struct nlattr *a) { struct ovs_conntrack_info *ct_info = nla_data(a); __ovs_ct_free_action(ct_info); } static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info) { if (ct_info->helper) module_put(ct_info->helper->me); if (ct_info->ct) nf_ct_tmpl_free(ct_info->ct); } void ovs_ct_init(struct net *net) { unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE; struct ovs_net *ovs_net = net_generic(net, ovs_net_id); if (nf_connlabels_get(net, n_bits - 1)) { ovs_net->xt_label = false; OVS_NLERR(true, "Failed to set connlabel length"); } else { ovs_net->xt_label = true; } } void ovs_ct_exit(struct net *net) { struct ovs_net *ovs_net = net_generic(net, ovs_net_id); if (ovs_net->xt_label) nf_connlabels_put(net); }