/* * Copyright (c) 2015, 2016, 2017 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 #include #include #include #include #include #include "bitmap.h" #include "conntrack.h" #include "conntrack-private.h" #include "coverage.h" #include "csum.h" #include "ct-dpif.h" #include "dp-packet.h" #include "flow.h" #include "netdev.h" #include "odp-netlink.h" #include "openvswitch/hmap.h" #include "openvswitch/vlog.h" #include "ovs-rcu.h" #include "ovs-thread.h" #include "openvswitch/poll-loop.h" #include "random.h" #include "timeval.h" VLOG_DEFINE_THIS_MODULE(conntrack); COVERAGE_DEFINE(conntrack_full); COVERAGE_DEFINE(conntrack_long_cleanup); struct conn_lookup_ctx { struct conn_key key; struct conn *conn; uint32_t hash; bool reply; bool icmp_related; }; enum ftp_ctl_pkt { /* Control packets with address and/or port specifiers. */ CT_FTP_CTL_INTEREST, /* Control packets without address and/or port specifiers. */ CT_FTP_CTL_OTHER, CT_FTP_CTL_INVALID, }; enum ct_alg_mode { CT_FTP_MODE_ACTIVE, CT_FTP_MODE_PASSIVE, CT_TFTP_MODE, }; enum ct_alg_ctl_type { CT_ALG_CTL_NONE, CT_ALG_CTL_FTP, CT_ALG_CTL_TFTP, }; static bool conn_key_extract(struct conntrack *, struct dp_packet *, ovs_be16 dl_type, struct conn_lookup_ctx *, uint16_t zone); static uint32_t conn_key_hash(const struct conn_key *, uint32_t basis); static void conn_key_reverse(struct conn_key *); static void conn_key_lookup(struct conntrack_bucket *ctb, struct conn_lookup_ctx *ctx, long long now); static bool valid_new(struct dp_packet *pkt, struct conn_key *); static struct conn *new_conn(struct conntrack_bucket *, struct dp_packet *pkt, struct conn_key *, long long now); static void delete_conn(struct conn *); static enum ct_update_res conn_update(struct conn *, struct conntrack_bucket *ctb, struct dp_packet *, bool reply, long long now); static bool conn_expired(struct conn *, long long now); static void set_mark(struct dp_packet *, struct conn *, uint32_t val, uint32_t mask); static void set_label(struct dp_packet *, struct conn *, const struct ovs_key_ct_labels *val, const struct ovs_key_ct_labels *mask); static void *clean_thread_main(void *f_); static struct nat_conn_key_node * nat_conn_keys_lookup(struct hmap *nat_conn_keys, const struct conn_key *key, uint32_t basis); static bool nat_conn_keys_insert(struct hmap *nat_conn_keys, const struct conn *nat_conn, uint32_t hash_basis); static void nat_conn_keys_remove(struct hmap *nat_conn_keys, const struct conn_key *key, uint32_t basis); static bool nat_select_range_tuple(struct conntrack *ct, const struct conn *conn, struct conn *nat_conn); static uint8_t reverse_icmp_type(uint8_t type); static uint8_t reverse_icmp6_type(uint8_t type); static inline bool extract_l3_ipv4(struct conn_key *key, const void *data, size_t size, const char **new_data, bool validate_checksum); static inline bool extract_l3_ipv6(struct conn_key *key, const void *data, size_t size, const char **new_data); static struct alg_exp_node * expectation_lookup(struct hmap *alg_expectations, const struct conn_key *key, uint32_t basis); static int repl_ftp_v4_addr(struct dp_packet *pkt, ovs_be32 v4_addr_rep, char *ftp_data_v4_start, size_t addr_offset_from_ftp_data_start); static enum ftp_ctl_pkt process_ftp_ctl_v4(struct conntrack *ct, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, ovs_be32 *v4_addr_rep, char **ftp_data_v4_start, size_t *addr_offset_from_ftp_data_start); static enum ftp_ctl_pkt detect_ftp_ctl_type(const struct conn_lookup_ctx *ctx, struct dp_packet *pkt); static struct ct_l4_proto *l4_protos[] = { [IPPROTO_TCP] = &ct_proto_tcp, [IPPROTO_UDP] = &ct_proto_other, [IPPROTO_ICMP] = &ct_proto_icmp4, [IPPROTO_ICMPV6] = &ct_proto_icmp6, }; static void handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, enum ftp_ctl_pkt ftp_ctl, bool nat); static void handle_tftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx OVS_UNUSED, struct dp_packet *pkt OVS_UNUSED, const struct conn *conn_for_expectation, long long now, enum ftp_ctl_pkt ftp_ctl OVS_UNUSED, bool nat OVS_UNUSED); typedef void (*alg_helper)(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, enum ftp_ctl_pkt ftp_ctl, bool nat); static alg_helper alg_helpers[] = { [CT_ALG_CTL_NONE] = NULL, [CT_ALG_CTL_FTP] = handle_ftp_ctl, [CT_ALG_CTL_TFTP] = handle_tftp_ctl, }; long long ct_timeout_val[] = { #define CT_TIMEOUT(NAME, VAL) [CT_TM_##NAME] = VAL, CT_TIMEOUTS #undef CT_TIMEOUT }; /* The maximum TCP or UDP port number. */ #define CT_MAX_L4_PORT 65535 /* Alg expectation timeout. */ #define CT_ALG_EXP_TIMEOUT (30 * 1000) /* String buffer used for parsing FTP string messages. * This is sized about twice what is needed to leave some * margin of error. */ #define LARGEST_FTP_MSG_OF_INTEREST 128 /* FTP port string used in active mode. */ #define FTP_PORT_CMD "PORT" /* FTP pasv string used in passive mode. */ #define FTP_PASV_REPLY_CODE "227" /* Maximum decimal digits for port in FTP command. * The port is represented as two 3 digit numbers with the * high part a multiple of 256. */ #define MAX_FTP_PORT_DGTS 3 /* FTP extension EPRT string used for active mode. */ #define FTP_EPRT_CMD "EPRT" /* FTP extension EPSV string used for passive mode. */ #define FTP_EPSV_REPLY "EXTENDED PASSIVE" /* Maximum decimal digits for port in FTP extended command. */ #define MAX_EXT_FTP_PORT_DGTS 5 /* FTP extended command code for IPv6. */ #define FTP_AF_V6 '2' /* Used to indicate a wildcard L4 source port number for ALGs. * This is used for port numbers that we cannot predict in * expectations. */ #define ALG_WC_SRC_PORT 0 /* If the total number of connections goes above this value, no new connections * are accepted; this is for CT_CONN_TYPE_DEFAULT connections. */ #define DEFAULT_N_CONN_LIMIT 3000000 /* Does a member by member comparison of two conn_keys; this * function must be kept in sync with struct conn_key; returns 0 * if the keys are equal or 1 if the keys are not equal. */ static int conn_key_cmp(const struct conn_key *key1, const struct conn_key *key2) { if (!memcmp(&key1->src.addr, &key2->src.addr, sizeof key1->src.addr) && !memcmp(&key1->dst.addr, &key2->dst.addr, sizeof key1->dst.addr) && (key1->src.icmp_id == key2->src.icmp_id) && (key1->src.icmp_type == key2->src.icmp_type) && (key1->src.icmp_code == key2->src.icmp_code) && (key1->dst.icmp_id == key2->dst.icmp_id) && (key1->dst.icmp_type == key2->dst.icmp_type) && (key1->dst.icmp_code == key2->dst.icmp_code) && (key1->dl_type == key2->dl_type) && (key1->zone == key2->zone) && (key1->nw_proto == key2->nw_proto)) { return 0; } return 1; } static void ct_print_conn_info(struct conn *c, char *log_msg, enum vlog_level vll, bool force, bool rl_on) { #define CT_VLOG(RL_ON, LEVEL, ...) \ do { \ if (RL_ON) { \ static struct vlog_rate_limit rl_ = VLOG_RATE_LIMIT_INIT(5, 5); \ vlog_rate_limit(&this_module, LEVEL, &rl_, __VA_ARGS__); \ } else { \ vlog(&this_module, LEVEL, __VA_ARGS__); \ } \ } while (0) if (OVS_UNLIKELY(force || vlog_is_enabled(&this_module, vll))) { if (c->key.dl_type == htons(ETH_TYPE_IP)) { CT_VLOG(rl_on, vll, "%s: src ip "IP_FMT" dst ip "IP_FMT" rev src " "ip "IP_FMT" rev dst ip "IP_FMT" src/dst ports " "%"PRIu16"/%"PRIu16" rev src/dst ports " "%"PRIu16"/%"PRIu16" zone/rev zone " "%"PRIu16"/%"PRIu16" nw_proto/rev nw_proto " "%"PRIu8"/%"PRIu8, log_msg, IP_ARGS(c->key.src.addr.ipv4_aligned), IP_ARGS(c->key.dst.addr.ipv4_aligned), IP_ARGS(c->rev_key.src.addr.ipv4_aligned), IP_ARGS(c->rev_key.dst.addr.ipv4_aligned), ntohs(c->key.src.port), ntohs(c->key.dst.port), ntohs(c->rev_key.src.port), ntohs(c->rev_key.dst.port), c->key.zone, c->rev_key.zone, c->key.nw_proto, c->rev_key.nw_proto); } else { char ip6_s[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &c->key.src.addr.ipv6, ip6_s, sizeof ip6_s); char ip6_d[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &c->key.dst.addr.ipv6, ip6_d, sizeof ip6_d); char ip6_rs[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &c->rev_key.src.addr.ipv6, ip6_rs, sizeof ip6_rs); char ip6_rd[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &c->rev_key.dst.addr.ipv6, ip6_rd, sizeof ip6_rd); CT_VLOG(rl_on, vll, "%s: src ip %s dst ip %s rev src ip %s" " rev dst ip %s src/dst ports %"PRIu16"/%"PRIu16 " rev src/dst ports %"PRIu16"/%"PRIu16" zone/rev zone " "%"PRIu16"/%"PRIu16" nw_proto/rev nw_proto " "%"PRIu8"/%"PRIu8, log_msg, ip6_s, ip6_d, ip6_rs, ip6_rd, ntohs(c->key.src.port), ntohs(c->key.dst.port), ntohs(c->rev_key.src.port), ntohs(c->rev_key.dst.port), c->key.zone, c->rev_key.zone, c->key.nw_proto, c->rev_key.nw_proto); } } } /* Initializes the connection tracker 'ct'. The caller is responsible for * calling 'conntrack_destroy()', when the instance is not needed anymore */ void conntrack_init(struct conntrack *ct) { unsigned i, j; long long now = time_msec(); ct_rwlock_init(&ct->resources_lock); ct_rwlock_wrlock(&ct->resources_lock); hmap_init(&ct->nat_conn_keys); hmap_init(&ct->alg_expectations); ovs_list_init(&ct->alg_exp_list); ct_rwlock_unlock(&ct->resources_lock); for (i = 0; i < CONNTRACK_BUCKETS; i++) { struct conntrack_bucket *ctb = &ct->buckets[i]; ct_lock_init(&ctb->lock); ct_lock_lock(&ctb->lock); hmap_init(&ctb->connections); for (j = 0; j < ARRAY_SIZE(ctb->exp_lists); j++) { ovs_list_init(&ctb->exp_lists[j]); } ct_lock_unlock(&ctb->lock); ovs_mutex_init(&ctb->cleanup_mutex); ovs_mutex_lock(&ctb->cleanup_mutex); ctb->next_cleanup = now + CT_TM_MIN; ovs_mutex_unlock(&ctb->cleanup_mutex); } ct->hash_basis = random_uint32(); atomic_count_init(&ct->n_conn, 0); atomic_init(&ct->n_conn_limit, DEFAULT_N_CONN_LIMIT); latch_init(&ct->clean_thread_exit); ct->clean_thread = ovs_thread_create("ct_clean", clean_thread_main, ct); } /* Destroys the connection tracker 'ct' and frees all the allocated memory. */ void conntrack_destroy(struct conntrack *ct) { unsigned i; latch_set(&ct->clean_thread_exit); pthread_join(ct->clean_thread, NULL); latch_destroy(&ct->clean_thread_exit); for (i = 0; i < CONNTRACK_BUCKETS; i++) { struct conntrack_bucket *ctb = &ct->buckets[i]; struct conn *conn; ovs_mutex_destroy(&ctb->cleanup_mutex); ct_lock_lock(&ctb->lock); HMAP_FOR_EACH_POP (conn, node, &ctb->connections) { if (conn->conn_type == CT_CONN_TYPE_DEFAULT) { atomic_count_dec(&ct->n_conn); } delete_conn(conn); } hmap_destroy(&ctb->connections); ct_lock_unlock(&ctb->lock); ct_lock_destroy(&ctb->lock); } ct_rwlock_wrlock(&ct->resources_lock); struct nat_conn_key_node *nat_conn_key_node; HMAP_FOR_EACH_POP (nat_conn_key_node, node, &ct->nat_conn_keys) { free(nat_conn_key_node); } hmap_destroy(&ct->nat_conn_keys); struct alg_exp_node *alg_exp_node; HMAP_FOR_EACH_POP (alg_exp_node, node, &ct->alg_expectations) { free(alg_exp_node); } ovs_list_poison(&ct->alg_exp_list); hmap_destroy(&ct->alg_expectations); ct_rwlock_unlock(&ct->resources_lock); ct_rwlock_destroy(&ct->resources_lock); } static unsigned hash_to_bucket(uint32_t hash) { /* Extracts the most significant bits in hash. The least significant bits * are already used internally by the hmap implementation. */ BUILD_ASSERT(CONNTRACK_BUCKETS_SHIFT < 32 && CONNTRACK_BUCKETS_SHIFT >= 1); return (hash >> (32 - CONNTRACK_BUCKETS_SHIFT)) % CONNTRACK_BUCKETS; } static void write_ct_md(struct dp_packet *pkt, uint16_t zone, const struct conn *conn, const struct conn_key *key, const struct alg_exp_node *alg_exp) { pkt->md.ct_state |= CS_TRACKED; pkt->md.ct_zone = zone; pkt->md.ct_mark = conn ? conn->mark : 0; pkt->md.ct_label = conn ? conn->label : OVS_U128_ZERO; /* Use the original direction tuple if we have it. */ if (conn) { if (conn->alg_related) { key = &conn->master_key; } else { key = &conn->key; } } else if (alg_exp) { pkt->md.ct_mark = alg_exp->master_mark; pkt->md.ct_label = alg_exp->master_label; key = &alg_exp->master_key; } pkt->md.ct_orig_tuple_ipv6 = false; if (key) { if (key->dl_type == htons(ETH_TYPE_IP)) { pkt->md.ct_orig_tuple.ipv4 = (struct ovs_key_ct_tuple_ipv4) { key->src.addr.ipv4_aligned, key->dst.addr.ipv4_aligned, key->nw_proto != IPPROTO_ICMP ? key->src.port : htons(key->src.icmp_type), key->nw_proto != IPPROTO_ICMP ? key->dst.port : htons(key->src.icmp_code), key->nw_proto, }; } else { pkt->md.ct_orig_tuple_ipv6 = true; pkt->md.ct_orig_tuple.ipv6 = (struct ovs_key_ct_tuple_ipv6) { key->src.addr.ipv6_aligned, key->dst.addr.ipv6_aligned, key->nw_proto != IPPROTO_ICMPV6 ? key->src.port : htons(key->src.icmp_type), key->nw_proto != IPPROTO_ICMPV6 ? key->dst.port : htons(key->src.icmp_code), key->nw_proto, }; } } else { memset(&pkt->md.ct_orig_tuple, 0, sizeof pkt->md.ct_orig_tuple); } } static uint8_t get_ip_proto(const struct dp_packet *pkt) { uint8_t ip_proto; struct eth_header *l2 = dp_packet_eth(pkt); if (l2->eth_type == htons(ETH_TYPE_IPV6)) { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); ip_proto = nh6->ip6_ctlun.ip6_un1.ip6_un1_nxt; } else { struct ip_header *l3_hdr = dp_packet_l3(pkt); ip_proto = l3_hdr->ip_proto; } return ip_proto; } static bool is_ftp_ctl(const enum ct_alg_ctl_type ct_alg_ctl) { return ct_alg_ctl == CT_ALG_CTL_FTP; } static enum ct_alg_ctl_type get_alg_ctl_type(const struct dp_packet *pkt, ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper) { /* CT_IPPORT_FTP/TFTP is used because IPPORT_FTP/TFTP in not defined * in OSX, at least in in.h. Since these values will never change, remove * the external dependency. */ enum { CT_IPPORT_FTP = 21 }; enum { CT_IPPORT_TFTP = 69 }; uint8_t ip_proto = get_ip_proto(pkt); struct udp_header *uh = dp_packet_l4(pkt); struct tcp_header *th = dp_packet_l4(pkt); ovs_be16 ftp_src_port = htons(CT_IPPORT_FTP); ovs_be16 ftp_dst_port = htons(CT_IPPORT_FTP); ovs_be16 tftp_dst_port = htons(CT_IPPORT_TFTP); if (OVS_UNLIKELY(tp_dst)) { if (helper && !strncmp(helper, "ftp", strlen("ftp"))) { ftp_dst_port = tp_dst; } else if (helper && !strncmp(helper, "tftp", strlen("tftp"))) { tftp_dst_port = tp_dst; } } else if (OVS_UNLIKELY(tp_src)) { if (helper && !strncmp(helper, "ftp", strlen("ftp"))) { ftp_src_port = tp_src; } } if (ip_proto == IPPROTO_UDP && uh->udp_dst == tftp_dst_port) { return CT_ALG_CTL_TFTP; } else if (ip_proto == IPPROTO_TCP && (th->tcp_src == ftp_src_port || th->tcp_dst == ftp_dst_port)) { return CT_ALG_CTL_FTP; } return CT_ALG_CTL_NONE; } static void handle_alg_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, enum ct_alg_ctl_type ct_alg_ctl, const struct conn *conn, long long now, bool nat, const struct conn *conn_for_expectation) { /* ALG control packet handling with expectation creation. */ if (OVS_UNLIKELY(alg_helpers[ct_alg_ctl] && conn && conn->alg)) { alg_helpers[ct_alg_ctl](ct, ctx, pkt, conn_for_expectation, now, CT_FTP_CTL_INTEREST, nat); } } static void alg_exp_init_expiration(struct conntrack *ct, struct alg_exp_node *alg_exp_node, long long now) OVS_REQ_WRLOCK(ct->resources_lock) { alg_exp_node->expiration = now + CT_ALG_EXP_TIMEOUT; ovs_list_push_back(&ct->alg_exp_list, &alg_exp_node->exp_node); } static void pat_packet(struct dp_packet *pkt, const struct conn *conn) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th = dp_packet_l4(pkt); packet_set_tcp_port(pkt, conn->rev_key.dst.port, th->tcp_dst); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh = dp_packet_l4(pkt); packet_set_udp_port(pkt, conn->rev_key.dst.port, uh->udp_dst); } } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th = dp_packet_l4(pkt); packet_set_tcp_port(pkt, th->tcp_src, conn->rev_key.src.port); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh = dp_packet_l4(pkt); packet_set_udp_port(pkt, uh->udp_src, conn->rev_key.src.port); } } } static void nat_packet(struct dp_packet *pkt, const struct conn *conn, bool related) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { pkt->md.ct_state |= CS_SRC_NAT; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { struct ip_header *nh = dp_packet_l3(pkt); packet_set_ipv4_addr(pkt, &nh->ip_src, conn->rev_key.dst.addr.ipv4_aligned); } else { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); packet_set_ipv6_addr(pkt, conn->key.nw_proto, nh6->ip6_src.be32, &conn->rev_key.dst.addr.ipv6_aligned, true); } if (!related) { pat_packet(pkt, conn); } } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { pkt->md.ct_state |= CS_DST_NAT; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { struct ip_header *nh = dp_packet_l3(pkt); packet_set_ipv4_addr(pkt, &nh->ip_dst, conn->rev_key.src.addr.ipv4_aligned); } else { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); packet_set_ipv6_addr(pkt, conn->key.nw_proto, nh6->ip6_dst.be32, &conn->rev_key.src.addr.ipv6_aligned, true); } if (!related) { pat_packet(pkt, conn); } } } static void un_pat_packet(struct dp_packet *pkt, const struct conn *conn) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th = dp_packet_l4(pkt); packet_set_tcp_port(pkt, th->tcp_src, conn->key.src.port); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh = dp_packet_l4(pkt); packet_set_udp_port(pkt, uh->udp_src, conn->key.src.port); } } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th = dp_packet_l4(pkt); packet_set_tcp_port(pkt, conn->key.dst.port, th->tcp_dst); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh = dp_packet_l4(pkt); packet_set_udp_port(pkt, conn->key.dst.port, uh->udp_dst); } } } static void reverse_pat_packet(struct dp_packet *pkt, const struct conn *conn) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th_in = dp_packet_l4(pkt); packet_set_tcp_port(pkt, conn->key.src.port, th_in->tcp_dst); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh_in = dp_packet_l4(pkt); packet_set_udp_port(pkt, conn->key.src.port, uh_in->udp_dst); } } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { if (conn->key.nw_proto == IPPROTO_TCP) { struct tcp_header *th_in = dp_packet_l4(pkt); packet_set_tcp_port(pkt, th_in->tcp_src, conn->key.dst.port); } else if (conn->key.nw_proto == IPPROTO_UDP) { struct udp_header *uh_in = dp_packet_l4(pkt); packet_set_udp_port(pkt, uh_in->udp_src, conn->key.dst.port); } } } static void reverse_nat_packet(struct dp_packet *pkt, const struct conn *conn) { char *tail = dp_packet_tail(pkt); char pad = dp_packet_l2_pad_size(pkt); struct conn_key inner_key; const char *inner_l4 = NULL; uint16_t orig_l3_ofs = pkt->l3_ofs; uint16_t orig_l4_ofs = pkt->l4_ofs; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { struct ip_header *nh = dp_packet_l3(pkt); struct icmp_header *icmp = dp_packet_l4(pkt); struct ip_header *inner_l3 = (struct ip_header *) (icmp + 1); extract_l3_ipv4(&inner_key, inner_l3, tail - ((char *)inner_l3) - pad, &inner_l4, false); pkt->l3_ofs += (char *) inner_l3 - (char *) nh; pkt->l4_ofs += inner_l4 - (char *) icmp; if (conn->nat_info->nat_action & NAT_ACTION_SRC) { packet_set_ipv4_addr(pkt, &inner_l3->ip_src, conn->key.src.addr.ipv4_aligned); } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { packet_set_ipv4_addr(pkt, &inner_l3->ip_dst, conn->key.dst.addr.ipv4_aligned); } reverse_pat_packet(pkt, conn); icmp->icmp_csum = 0; icmp->icmp_csum = csum(icmp, tail - (char *) icmp - pad); } else { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); struct icmp6_error_header *icmp6 = dp_packet_l4(pkt); struct ovs_16aligned_ip6_hdr *inner_l3_6 = (struct ovs_16aligned_ip6_hdr *) (icmp6 + 1); extract_l3_ipv6(&inner_key, inner_l3_6, tail - ((char *)inner_l3_6) - pad, &inner_l4); pkt->l3_ofs += (char *) inner_l3_6 - (char *) nh6; pkt->l4_ofs += inner_l4 - (char *) icmp6; if (conn->nat_info->nat_action & NAT_ACTION_SRC) { packet_set_ipv6_addr(pkt, conn->key.nw_proto, inner_l3_6->ip6_src.be32, &conn->key.src.addr.ipv6_aligned, true); } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { packet_set_ipv6_addr(pkt, conn->key.nw_proto, inner_l3_6->ip6_dst.be32, &conn->key.dst.addr.ipv6_aligned, true); } reverse_pat_packet(pkt, conn); uint32_t icmp6_csum = packet_csum_pseudoheader6(nh6); icmp6->icmp6_base.icmp6_cksum = 0; icmp6->icmp6_base.icmp6_cksum = csum_finish( csum_continue(icmp6_csum, icmp6, tail - (char *) icmp6 - pad)); } pkt->l3_ofs = orig_l3_ofs; pkt->l4_ofs = orig_l4_ofs; } static void un_nat_packet(struct dp_packet *pkt, const struct conn *conn, bool related) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { pkt->md.ct_state |= CS_DST_NAT; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { struct ip_header *nh = dp_packet_l3(pkt); packet_set_ipv4_addr(pkt, &nh->ip_dst, conn->key.src.addr.ipv4_aligned); } else { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); packet_set_ipv6_addr(pkt, conn->key.nw_proto, nh6->ip6_dst.be32, &conn->key.src.addr.ipv6_aligned, true); } if (OVS_UNLIKELY(related)) { reverse_nat_packet(pkt, conn); } else { un_pat_packet(pkt, conn); } } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { pkt->md.ct_state |= CS_SRC_NAT; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { struct ip_header *nh = dp_packet_l3(pkt); packet_set_ipv4_addr(pkt, &nh->ip_src, conn->key.dst.addr.ipv4_aligned); } else { struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); packet_set_ipv6_addr(pkt, conn->key.nw_proto, nh6->ip6_src.be32, &conn->key.dst.addr.ipv6_aligned, true); } if (OVS_UNLIKELY(related)) { reverse_nat_packet(pkt, conn); } else { un_pat_packet(pkt, conn); } } } /* Typical usage of this helper is in non per-packet code; * this is because the bucket lock needs to be held for lookup * and a hash would have already been needed. Hence, this function * is just intended for code clarity. */ static struct conn * conn_lookup(struct conntrack *ct, const struct conn_key *key, long long now) { struct conn_lookup_ctx ctx; ctx.conn = NULL; ctx.key = *key; ctx.hash = conn_key_hash(key, ct->hash_basis); unsigned bucket = hash_to_bucket(ctx.hash); conn_key_lookup(&ct->buckets[bucket], &ctx, now); return ctx.conn; } static void conn_seq_skew_set(struct conntrack *ct, const struct conn_key *key, long long now, int seq_skew, bool seq_skew_dir) { uint32_t hash = conn_key_hash(key, ct->hash_basis); unsigned bucket = hash_to_bucket(hash); ct_lock_lock(&ct->buckets[bucket].lock); struct conn *conn = conn_lookup(ct, key, now); if (conn && seq_skew) { conn->seq_skew = seq_skew; conn->seq_skew_dir = seq_skew_dir; } ct_lock_unlock(&ct->buckets[bucket].lock); } static void nat_clean(struct conntrack *ct, struct conn *conn, struct conntrack_bucket *ctb) OVS_REQUIRES(ctb->lock) { long long now = time_msec(); ct_rwlock_wrlock(&ct->resources_lock); nat_conn_keys_remove(&ct->nat_conn_keys, &conn->rev_key, ct->hash_basis); ct_rwlock_unlock(&ct->resources_lock); ct_lock_unlock(&ctb->lock); uint32_t hash_rev_conn = conn_key_hash(&conn->rev_key, ct->hash_basis); unsigned bucket_rev_conn = hash_to_bucket(hash_rev_conn); ct_lock_lock(&ct->buckets[bucket_rev_conn].lock); ct_rwlock_wrlock(&ct->resources_lock); struct conn *rev_conn = conn_lookup(ct, &conn->rev_key, now); struct nat_conn_key_node *nat_conn_key_node = nat_conn_keys_lookup(&ct->nat_conn_keys, &conn->rev_key, ct->hash_basis); /* In the unlikely event, rev conn was recreated, then skip * rev_conn cleanup. */ if (rev_conn && (!nat_conn_key_node || conn_key_cmp(&nat_conn_key_node->value, &rev_conn->rev_key))) { hmap_remove(&ct->buckets[bucket_rev_conn].connections, &rev_conn->node); free(rev_conn); } delete_conn(conn); ct_rwlock_unlock(&ct->resources_lock); ct_lock_unlock(&ct->buckets[bucket_rev_conn].lock); ct_lock_lock(&ctb->lock); } static void conn_clean(struct conntrack *ct, struct conn *conn, struct conntrack_bucket *ctb) OVS_REQUIRES(ctb->lock) { ovs_list_remove(&conn->exp_node); hmap_remove(&ctb->connections, &conn->node); atomic_count_dec(&ct->n_conn); if (conn->nat_info) { nat_clean(ct, conn, ctb); } else { delete_conn(conn); } } static bool ct_verify_helper(const char *helper, enum ct_alg_ctl_type ct_alg_ctl) { if (ct_alg_ctl == CT_ALG_CTL_NONE) { return true; } else if (helper) { if ((ct_alg_ctl == CT_ALG_CTL_FTP) && !strncmp(helper, "ftp", strlen("ftp"))) { return true; } else if ((ct_alg_ctl == CT_ALG_CTL_TFTP) && !strncmp(helper, "tftp", strlen("tftp"))) { return true; } else { return false; } } else { return false; } } /* This function is called with the bucket lock held. */ static struct conn * conn_not_found(struct conntrack *ct, struct dp_packet *pkt, struct conn_lookup_ctx *ctx, bool commit, long long now, const struct nat_action_info_t *nat_action_info, struct conn *conn_for_un_nat_copy, const char *helper, const struct alg_exp_node *alg_exp, enum ct_alg_ctl_type ct_alg_ctl) { unsigned bucket = hash_to_bucket(ctx->hash); struct conn *nc = NULL; if (!valid_new(pkt, &ctx->key)) { pkt->md.ct_state = CS_INVALID; return nc; } pkt->md.ct_state = CS_NEW; if (alg_exp) { pkt->md.ct_state |= CS_RELATED; } if (commit) { unsigned int n_conn_limit; atomic_read_relaxed(&ct->n_conn_limit, &n_conn_limit); if (atomic_count_get(&ct->n_conn) >= n_conn_limit) { COVERAGE_INC(conntrack_full); return nc; } nc = new_conn(&ct->buckets[bucket], pkt, &ctx->key, now); ctx->conn = nc; nc->rev_key = nc->key; conn_key_reverse(&nc->rev_key); if (ct_verify_helper(helper, ct_alg_ctl)) { nc->alg = nullable_xstrdup(helper); } if (alg_exp) { nc->alg_related = true; nc->mark = alg_exp->master_mark; nc->label = alg_exp->master_label; nc->master_key = alg_exp->master_key; } if (nat_action_info) { nc->nat_info = xmemdup(nat_action_info, sizeof *nc->nat_info); if (alg_exp) { if (alg_exp->passive_mode) { nc->rev_key.dst.addr = alg_exp->alg_nat_repl_addr; nc->nat_info->nat_action = NAT_ACTION_SRC; } else { nc->rev_key.src.addr = alg_exp->alg_nat_repl_addr; nc->nat_info->nat_action = NAT_ACTION_DST; } *conn_for_un_nat_copy = *nc; ct_rwlock_wrlock(&ct->resources_lock); bool new_insert = nat_conn_keys_insert(&ct->nat_conn_keys, conn_for_un_nat_copy, ct->hash_basis); ct_rwlock_unlock(&ct->resources_lock); if (!new_insert) { char *log_msg = xasprintf("Pre-existing alg " "nat_conn_key"); ct_print_conn_info(conn_for_un_nat_copy, log_msg, VLL_INFO, true, false); free(log_msg); } } else { *conn_for_un_nat_copy = *nc; ct_rwlock_wrlock(&ct->resources_lock); bool nat_res = nat_select_range_tuple( ct, nc, conn_for_un_nat_copy); if (!nat_res) { goto nat_res_exhaustion; } /* Update nc with nat adjustments made to * conn_for_un_nat_copy by nat_select_range_tuple(). */ *nc = *conn_for_un_nat_copy; ct_rwlock_unlock(&ct->resources_lock); } conn_for_un_nat_copy->conn_type = CT_CONN_TYPE_UN_NAT; conn_for_un_nat_copy->nat_info = NULL; conn_for_un_nat_copy->alg = NULL; nat_packet(pkt, nc, ctx->icmp_related); } hmap_insert(&ct->buckets[bucket].connections, &nc->node, ctx->hash); atomic_count_inc(&ct->n_conn); } return nc; /* This would be a user error or a DOS attack. * A user error is prevented by allocating enough * combinations of NAT addresses when combined with * ephemeral ports. A DOS attack should be protected * against with firewall rules or a separate firewall. * Also using zone partitioning can limit DoS impact. */ nat_res_exhaustion: ovs_list_remove(&nc->exp_node); delete_conn(nc); /* conn_for_un_nat_copy is a local variable in process_one; this * memset() serves to document that conn_for_un_nat_copy is from * this point on unused. */ memset(conn_for_un_nat_copy, 0, sizeof *conn_for_un_nat_copy); ct_rwlock_unlock(&ct->resources_lock); static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5); VLOG_WARN_RL(&rl, "Unable to NAT due to tuple space exhaustion - " "if DoS attack, use firewalling and/or zone partitioning."); return NULL; } static bool conn_update_state(struct conntrack *ct, struct dp_packet *pkt, struct conn_lookup_ctx *ctx, struct conn **conn, long long now, unsigned bucket) OVS_REQUIRES(ct->buckets[bucket].lock) { bool create_new_conn = false; if (ctx->icmp_related) { pkt->md.ct_state |= CS_RELATED; if (ctx->reply) { pkt->md.ct_state |= CS_REPLY_DIR; } } else { if ((*conn)->alg_related) { pkt->md.ct_state |= CS_RELATED; } enum ct_update_res res = conn_update(*conn, &ct->buckets[bucket], pkt, ctx->reply, now); switch (res) { case CT_UPDATE_VALID: pkt->md.ct_state |= CS_ESTABLISHED; pkt->md.ct_state &= ~CS_NEW; if (ctx->reply) { pkt->md.ct_state |= CS_REPLY_DIR; } break; case CT_UPDATE_INVALID: pkt->md.ct_state = CS_INVALID; break; case CT_UPDATE_NEW: conn_clean(ct, *conn, &ct->buckets[bucket]); create_new_conn = true; break; default: OVS_NOT_REACHED(); } } return create_new_conn; } static void create_un_nat_conn(struct conntrack *ct, struct conn *conn_for_un_nat_copy, long long now, bool alg_un_nat) { struct conn *nc = xmemdup(conn_for_un_nat_copy, sizeof *nc); nc->key = conn_for_un_nat_copy->rev_key; nc->rev_key = conn_for_un_nat_copy->key; uint32_t un_nat_hash = conn_key_hash(&nc->key, ct->hash_basis); unsigned un_nat_conn_bucket = hash_to_bucket(un_nat_hash); ct_lock_lock(&ct->buckets[un_nat_conn_bucket].lock); struct conn *rev_conn = conn_lookup(ct, &nc->key, now); if (alg_un_nat) { if (!rev_conn) { hmap_insert(&ct->buckets[un_nat_conn_bucket].connections, &nc->node, un_nat_hash); } else { char *log_msg = xasprintf("Unusual condition for un_nat conn " "create for alg: rev_conn %p", rev_conn); ct_print_conn_info(nc, log_msg, VLL_INFO, true, false); free(log_msg); free(nc); } } else { ct_rwlock_rdlock(&ct->resources_lock); struct nat_conn_key_node *nat_conn_key_node = nat_conn_keys_lookup(&ct->nat_conn_keys, &nc->key, ct->hash_basis); if (nat_conn_key_node && !conn_key_cmp(&nat_conn_key_node->value, &nc->rev_key) && !rev_conn) { hmap_insert(&ct->buckets[un_nat_conn_bucket].connections, &nc->node, un_nat_hash); } else { char *log_msg = xasprintf("Unusual condition for un_nat conn " "create: nat_conn_key_node/rev_conn " "%p/%p", nat_conn_key_node, rev_conn); ct_print_conn_info(nc, log_msg, VLL_INFO, true, false); free(log_msg); free(nc); } ct_rwlock_unlock(&ct->resources_lock); } ct_lock_unlock(&ct->buckets[un_nat_conn_bucket].lock); } static void handle_nat(struct dp_packet *pkt, struct conn *conn, uint16_t zone, bool reply, bool related) { if (conn->nat_info && (!(pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT)) || (pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT) && zone != pkt->md.ct_zone))) { if (pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT)) { pkt->md.ct_state &= ~(CS_SRC_NAT | CS_DST_NAT); } if (reply) { un_nat_packet(pkt, conn, related); } else { nat_packet(pkt, conn, related); } } } static bool check_orig_tuple(struct conntrack *ct, struct dp_packet *pkt, struct conn_lookup_ctx *ctx_in, long long now, unsigned *bucket, struct conn **conn, const struct nat_action_info_t *nat_action_info) OVS_REQUIRES(ct->buckets[*bucket].lock) { if ((ctx_in->key.dl_type == htons(ETH_TYPE_IP) && !pkt->md.ct_orig_tuple.ipv4.ipv4_proto) || (ctx_in->key.dl_type == htons(ETH_TYPE_IPV6) && !pkt->md.ct_orig_tuple.ipv6.ipv6_proto) || !(pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT)) || nat_action_info) { return false; } ct_lock_unlock(&ct->buckets[*bucket].lock); struct conn_lookup_ctx ctx; memset(&ctx, 0 , sizeof ctx); ctx.conn = NULL; if (ctx_in->key.dl_type == htons(ETH_TYPE_IP)) { ctx.key.src.addr.ipv4_aligned = pkt->md.ct_orig_tuple.ipv4.ipv4_src; ctx.key.dst.addr.ipv4_aligned = pkt->md.ct_orig_tuple.ipv4.ipv4_dst; if (ctx_in->key.nw_proto == IPPROTO_ICMP) { ctx.key.src.icmp_id = ctx_in->key.src.icmp_id; ctx.key.dst.icmp_id = ctx_in->key.dst.icmp_id; uint16_t src_port = ntohs(pkt->md.ct_orig_tuple.ipv4.src_port); ctx.key.src.icmp_type = (uint8_t) src_port; ctx.key.dst.icmp_type = reverse_icmp_type(ctx.key.src.icmp_type); } else { ctx.key.src.port = pkt->md.ct_orig_tuple.ipv4.src_port; ctx.key.dst.port = pkt->md.ct_orig_tuple.ipv4.dst_port; } ctx.key.nw_proto = pkt->md.ct_orig_tuple.ipv4.ipv4_proto; } else { ctx.key.src.addr.ipv6_aligned = pkt->md.ct_orig_tuple.ipv6.ipv6_src; ctx.key.dst.addr.ipv6_aligned = pkt->md.ct_orig_tuple.ipv6.ipv6_dst; if (ctx_in->key.nw_proto == IPPROTO_ICMPV6) { ctx.key.src.icmp_id = ctx_in->key.src.icmp_id; ctx.key.dst.icmp_id = ctx_in->key.dst.icmp_id; uint16_t src_port = ntohs(pkt->md.ct_orig_tuple.ipv6.src_port); ctx.key.src.icmp_type = (uint8_t) src_port; ctx.key.dst.icmp_type = reverse_icmp6_type(ctx.key.src.icmp_type); } else { ctx.key.src.port = pkt->md.ct_orig_tuple.ipv6.src_port; ctx.key.dst.port = pkt->md.ct_orig_tuple.ipv6.dst_port; } ctx.key.nw_proto = pkt->md.ct_orig_tuple.ipv6.ipv6_proto; } ctx.key.dl_type = ctx_in->key.dl_type; ctx.key.zone = pkt->md.ct_zone; ctx.hash = conn_key_hash(&ctx.key, ct->hash_basis); *bucket = hash_to_bucket(ctx.hash); ct_lock_lock(&ct->buckets[*bucket].lock); conn_key_lookup(&ct->buckets[*bucket], &ctx, now); *conn = ctx.conn; return *conn ? true : false; } static bool is_un_nat_conn_valid(const struct conn *un_nat_conn) { return un_nat_conn->conn_type == CT_CONN_TYPE_UN_NAT; } static bool conn_update_state_alg(struct conntrack *ct, struct dp_packet *pkt, struct conn_lookup_ctx *ctx, struct conn *conn, const struct nat_action_info_t *nat_action_info, enum ct_alg_ctl_type ct_alg_ctl, long long now, unsigned bucket, bool *create_new_conn) OVS_REQUIRES(ct->buckets[bucket].lock) { if (is_ftp_ctl(ct_alg_ctl)) { /* Keep sequence tracking in sync with the source of the * sequence skew. */ if (ctx->reply != conn->seq_skew_dir) { handle_ftp_ctl(ct, ctx, pkt, conn, now, CT_FTP_CTL_OTHER, !!nat_action_info); *create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket); } else { *create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket); handle_ftp_ctl(ct, ctx, pkt, conn, now, CT_FTP_CTL_OTHER, !!nat_action_info); } return true; } return false; } static void process_one(struct conntrack *ct, struct dp_packet *pkt, struct conn_lookup_ctx *ctx, uint16_t zone, bool force, bool commit, long long now, const uint32_t *setmark, const struct ovs_key_ct_labels *setlabel, const struct nat_action_info_t *nat_action_info, ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper) { struct conn *conn; unsigned bucket = hash_to_bucket(ctx->hash); ct_lock_lock(&ct->buckets[bucket].lock); conn_key_lookup(&ct->buckets[bucket], ctx, now); conn = ctx->conn; /* Delete found entry if in wrong direction. 'force' implies commit. */ if (conn && force && ctx->reply) { conn_clean(ct, conn, &ct->buckets[bucket]); conn = NULL; } if (OVS_LIKELY(conn)) { if (conn->conn_type == CT_CONN_TYPE_UN_NAT) { ctx->reply = true; struct conn_lookup_ctx ctx2; ctx2.conn = NULL; ctx2.key = conn->rev_key; ctx2.hash = conn_key_hash(&conn->rev_key, ct->hash_basis); ct_lock_unlock(&ct->buckets[bucket].lock); bucket = hash_to_bucket(ctx2.hash); ct_lock_lock(&ct->buckets[bucket].lock); conn_key_lookup(&ct->buckets[bucket], &ctx2, now); if (ctx2.conn) { conn = ctx2.conn; } else { /* It is a race condition where conn has timed out and removed * between unlock of the rev_conn and lock of the forward conn; * nothing to do. */ pkt->md.ct_state |= CS_TRACKED | CS_INVALID; ct_lock_unlock(&ct->buckets[bucket].lock); return; } } } bool create_new_conn = false; struct conn conn_for_un_nat_copy; conn_for_un_nat_copy.conn_type = CT_CONN_TYPE_DEFAULT; enum ct_alg_ctl_type ct_alg_ctl = get_alg_ctl_type(pkt, tp_src, tp_dst, helper); if (OVS_LIKELY(conn)) { if (OVS_LIKELY(!conn_update_state_alg(ct, pkt, ctx, conn, nat_action_info, ct_alg_ctl, now, bucket, &create_new_conn))) { create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket); } if (nat_action_info && !create_new_conn) { handle_nat(pkt, conn, zone, ctx->reply, ctx->icmp_related); } }else if (check_orig_tuple(ct, pkt, ctx, now, &bucket, &conn, nat_action_info)) { create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket); } else { if (ctx->icmp_related) { /* An icmp related conn should always be found; no new connection is created based on an icmp related packet. */ pkt->md.ct_state = CS_INVALID; } else { create_new_conn = true; } } const struct alg_exp_node *alg_exp = NULL; if (OVS_UNLIKELY(create_new_conn)) { struct alg_exp_node alg_exp_entry; ct_rwlock_rdlock(&ct->resources_lock); alg_exp = expectation_lookup(&ct->alg_expectations, &ctx->key, ct->hash_basis); if (alg_exp) { alg_exp_entry = *alg_exp; alg_exp = &alg_exp_entry; } ct_rwlock_unlock(&ct->resources_lock); conn = conn_not_found(ct, pkt, ctx, commit, now, nat_action_info, &conn_for_un_nat_copy, helper, alg_exp, ct_alg_ctl); } write_ct_md(pkt, zone, conn, &ctx->key, alg_exp); if (conn && setmark) { set_mark(pkt, conn, setmark[0], setmark[1]); } if (conn && setlabel) { set_label(pkt, conn, &setlabel[0], &setlabel[1]); } struct conn conn_for_expectation; if (OVS_UNLIKELY((ct_alg_ctl != CT_ALG_CTL_NONE) && conn)) { conn_for_expectation = *conn; } ct_lock_unlock(&ct->buckets[bucket].lock); if (is_un_nat_conn_valid(&conn_for_un_nat_copy)) { create_un_nat_conn(ct, &conn_for_un_nat_copy, now, !!alg_exp); } handle_alg_ctl(ct, ctx, pkt, ct_alg_ctl, conn, now, !!nat_action_info, &conn_for_expectation); } /* Sends the packets in '*pkt_batch' through the connection tracker 'ct'. All * the packets should have the same 'dl_type' (IPv4 or IPv6) and should have * the l3 and and l4 offset properly set. * * If 'commit' is true, the packets are allowed to create new entries in the * connection tables. 'setmark', if not NULL, should point to a two * elements array containing a value and a mask to set the connection mark. * 'setlabel' behaves similarly for the connection label.*/ int conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch, ovs_be16 dl_type, bool force, bool commit, uint16_t zone, const uint32_t *setmark, const struct ovs_key_ct_labels *setlabel, ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper, const struct nat_action_info_t *nat_action_info, long long now) { struct dp_packet *packet; struct conn_lookup_ctx ctx; DP_PACKET_BATCH_FOR_EACH (packet, pkt_batch) { if (!conn_key_extract(ct, packet, dl_type, &ctx, zone)) { packet->md.ct_state = CS_INVALID; write_ct_md(packet, zone, NULL, NULL, NULL); continue; } process_one(ct, packet, &ctx, zone, force, commit, now, setmark, setlabel, nat_action_info, tp_src, tp_dst, helper); } return 0; } static void set_mark(struct dp_packet *pkt, struct conn *conn, uint32_t val, uint32_t mask) { if (conn->alg_related) { pkt->md.ct_mark = conn->mark; } else { pkt->md.ct_mark = val | (pkt->md.ct_mark & ~(mask)); conn->mark = pkt->md.ct_mark; } } static void set_label(struct dp_packet *pkt, struct conn *conn, const struct ovs_key_ct_labels *val, const struct ovs_key_ct_labels *mask) { if (conn->alg_related) { pkt->md.ct_label = conn->label; } else { ovs_u128 v, m; memcpy(&v, val, sizeof v); memcpy(&m, mask, sizeof m); pkt->md.ct_label.u64.lo = v.u64.lo | (pkt->md.ct_label.u64.lo & ~(m.u64.lo)); pkt->md.ct_label.u64.hi = v.u64.hi | (pkt->md.ct_label.u64.hi & ~(m.u64.hi)); conn->label = pkt->md.ct_label; } } /* Delete the expired connections from 'ctb', up to 'limit'. Returns the * earliest expiration time among the remaining connections in 'ctb'. Returns * LLONG_MAX if 'ctb' is empty. The return value might be smaller than 'now', * if 'limit' is reached */ static long long sweep_bucket(struct conntrack *ct, struct conntrack_bucket *ctb, long long now, size_t limit) OVS_REQUIRES(ctb->lock) { struct conn *conn, *next; long long min_expiration = LLONG_MAX; unsigned i; size_t count = 0; for (i = 0; i < N_CT_TM; i++) { LIST_FOR_EACH_SAFE (conn, next, exp_node, &ctb->exp_lists[i]) { if (conn->conn_type == CT_CONN_TYPE_DEFAULT) { if (!conn_expired(conn, now) || count >= limit) { min_expiration = MIN(min_expiration, conn->expiration); if (count >= limit) { /* Do not check other lists. */ COVERAGE_INC(conntrack_long_cleanup); return min_expiration; } break; } conn_clean(ct, conn, ctb); count++; } } } enum { MAX_ALG_EXP_TO_EXPIRE = 1000 }; size_t alg_exp_count = hmap_count(&ct->alg_expectations); /* XXX: revisit this. */ size_t max_to_expire = MAX(alg_exp_count/10, MAX_ALG_EXP_TO_EXPIRE); count = 0; ct_rwlock_wrlock(&ct->resources_lock); struct alg_exp_node *alg_exp_node, *alg_exp_node_next; LIST_FOR_EACH_SAFE (alg_exp_node, alg_exp_node_next, exp_node, &ct->alg_exp_list) { if (now < alg_exp_node->expiration || count >= max_to_expire) { min_expiration = MIN(min_expiration, alg_exp_node->expiration); break; } ovs_list_remove(&alg_exp_node->exp_node); hmap_remove(&ct->alg_expectations, &alg_exp_node->node); free(alg_exp_node); count++; } ct_rwlock_unlock(&ct->resources_lock); return min_expiration; } /* Cleans up old connection entries from 'ct'. Returns the time when the * next expiration might happen. The return value might be smaller than * 'now', meaning that an internal limit has been reached, and some expired * connections have not been deleted. */ static long long conntrack_clean(struct conntrack *ct, long long now) { long long next_wakeup = now + CT_TM_MIN; unsigned int n_conn_limit; size_t clean_count = 0; unsigned i; atomic_read_relaxed(&ct->n_conn_limit, &n_conn_limit); for (i = 0; i < CONNTRACK_BUCKETS; i++) { struct conntrack_bucket *ctb = &ct->buckets[i]; size_t prev_count; long long min_exp; ovs_mutex_lock(&ctb->cleanup_mutex); if (ctb->next_cleanup > now) { goto next_bucket; } ct_lock_lock(&ctb->lock); prev_count = hmap_count(&ctb->connections); /* If the connections are well distributed among buckets, we want to * limit to 10% of the global limit equally split among buckets. If * the bucket is busier than the others, we limit to 10% of its * current size. */ min_exp = sweep_bucket(ct, ctb, now, MAX(prev_count/10, n_conn_limit/(CONNTRACK_BUCKETS*10))); clean_count += prev_count - hmap_count(&ctb->connections); if (min_exp > now) { /* We call hmap_shrink() only if sweep_bucket() managed to delete * every expired connection. */ hmap_shrink(&ctb->connections); } ct_lock_unlock(&ctb->lock); ctb->next_cleanup = MIN(min_exp, now + CT_TM_MIN); next_bucket: next_wakeup = MIN(next_wakeup, ctb->next_cleanup); ovs_mutex_unlock(&ctb->cleanup_mutex); } VLOG_DBG("conntrack cleanup %"PRIuSIZE" entries in %lld msec", clean_count, time_msec() - now); return next_wakeup; } /* Cleanup: * * We must call conntrack_clean() periodically. conntrack_clean() return * value gives an hint on when the next cleanup must be done (either because * there is an actual connection that expires, or because a new connection * might be created with the minimum timeout). * * The logic below has two goals: * * - We want to reduce the number of wakeups and batch connection cleanup * when the load is not very high. CT_CLEAN_INTERVAL ensures that if we * are coping with the current cleanup tasks, then we wait at least * 5 seconds to do further cleanup. * * - We don't want to keep the buckets locked too long, as we might prevent * traffic from flowing. CT_CLEAN_MIN_INTERVAL ensures that if cleanup is * behind, there is at least some 200ms blocks of time when buckets will be * left alone, so the datapath can operate unhindered. */ #define CT_CLEAN_INTERVAL 5000 /* 5 seconds */ #define CT_CLEAN_MIN_INTERVAL 200 /* 0.2 seconds */ static void * clean_thread_main(void *f_) { struct conntrack *ct = f_; while (!latch_is_set(&ct->clean_thread_exit)) { long long next_wake; long long now = time_msec(); next_wake = conntrack_clean(ct, now); if (next_wake < now) { poll_timer_wait_until(now + CT_CLEAN_MIN_INTERVAL); } else { poll_timer_wait_until(MAX(next_wake, now + CT_CLEAN_INTERVAL)); } latch_wait(&ct->clean_thread_exit); poll_block(); } return NULL; } /* Key extraction */ /* The function stores a pointer to the first byte after the header in * '*new_data', if 'new_data' is not NULL. If it is NULL, the caller is * not interested in the header's tail, meaning that the header has * already been parsed (e.g. by flow_extract): we take this as a hint to * save a few checks. If 'validate_checksum' is true, the function returns * false if the IPv4 checksum is invalid. */ static inline bool extract_l3_ipv4(struct conn_key *key, const void *data, size_t size, const char **new_data, bool validate_checksum) { const struct ip_header *ip = data; size_t ip_len; if (new_data) { if (OVS_UNLIKELY(size < IP_HEADER_LEN)) { return false; } } ip_len = IP_IHL(ip->ip_ihl_ver) * 4; if (new_data) { if (OVS_UNLIKELY(ip_len < IP_HEADER_LEN)) { return false; } if (OVS_UNLIKELY(size < ip_len)) { return false; } *new_data = (char *) data + ip_len; } if (IP_IS_FRAGMENT(ip->ip_frag_off)) { return false; } if (validate_checksum && csum(data, ip_len) != 0) { return false; } key->src.addr.ipv4 = ip->ip_src; key->dst.addr.ipv4 = ip->ip_dst; key->nw_proto = ip->ip_proto; return true; } /* The function stores a pointer to the first byte after the header in * '*new_data', if 'new_data' is not NULL. If it is NULL, the caller is * not interested in the header's tail, meaning that the header has * already been parsed (e.g. by flow_extract): we take this as a hint to * save a few checks. */ static inline bool extract_l3_ipv6(struct conn_key *key, const void *data, size_t size, const char **new_data) { const struct ovs_16aligned_ip6_hdr *ip6 = data; if (new_data) { if (OVS_UNLIKELY(size < sizeof *ip6)) { return false; } } uint8_t nw_proto = ip6->ip6_nxt; uint8_t nw_frag = 0; data = ip6 + 1; size -= sizeof *ip6; if (!parse_ipv6_ext_hdrs(&data, &size, &nw_proto, &nw_frag)) { return false; } if (new_data) { *new_data = data; } if (nw_frag) { return false; } key->src.addr.ipv6 = ip6->ip6_src; key->dst.addr.ipv6 = ip6->ip6_dst; key->nw_proto = nw_proto; return true; } static inline bool checksum_valid(const struct conn_key *key, const void *data, size_t size, const void *l3) { uint32_t csum = 0; if (key->dl_type == htons(ETH_TYPE_IP)) { csum = packet_csum_pseudoheader(l3); } else if (key->dl_type == htons(ETH_TYPE_IPV6)) { csum = packet_csum_pseudoheader6(l3); } else { return false; } csum = csum_continue(csum, data, size); return csum_finish(csum) == 0; } static inline bool check_l4_tcp(const struct conn_key *key, const void *data, size_t size, const void *l3, bool validate_checksum) { const struct tcp_header *tcp = data; if (size < sizeof *tcp) { return false; } size_t tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4; if (OVS_UNLIKELY(tcp_len < TCP_HEADER_LEN || tcp_len > size)) { return false; } return validate_checksum ? checksum_valid(key, data, size, l3) : true; } static inline bool check_l4_udp(const struct conn_key *key, const void *data, size_t size, const void *l3, bool validate_checksum) { const struct udp_header *udp = data; if (size < sizeof *udp) { return false; } size_t udp_len = ntohs(udp->udp_len); if (OVS_UNLIKELY(udp_len < UDP_HEADER_LEN || udp_len > size)) { return false; } /* Validation must be skipped if checksum is 0 on IPv4 packets */ return (udp->udp_csum == 0 && key->dl_type == htons(ETH_TYPE_IP)) || (validate_checksum ? checksum_valid(key, data, size, l3) : true); } static inline bool check_l4_icmp(const void *data, size_t size, bool validate_checksum) { return validate_checksum ? csum(data, size) == 0 : true; } static inline bool check_l4_icmp6(const struct conn_key *key, const void *data, size_t size, const void *l3, bool validate_checksum) { return validate_checksum ? checksum_valid(key, data, size, l3) : true; } static inline bool extract_l4_tcp(struct conn_key *key, const void *data, size_t size) { const struct tcp_header *tcp = data; if (OVS_UNLIKELY(size < TCP_HEADER_LEN)) { return false; } key->src.port = tcp->tcp_src; key->dst.port = tcp->tcp_dst; /* Port 0 is invalid */ return key->src.port && key->dst.port; } static inline bool extract_l4_udp(struct conn_key *key, const void *data, size_t size) { const struct udp_header *udp = data; if (OVS_UNLIKELY(size < UDP_HEADER_LEN)) { return false; } key->src.port = udp->udp_src; key->dst.port = udp->udp_dst; /* Port 0 is invalid */ return key->src.port && key->dst.port; } static inline bool extract_l4(struct conn_key *key, const void *data, size_t size, bool *related, const void *l3, bool validate_checksum); static uint8_t reverse_icmp_type(uint8_t type) { switch (type) { case ICMP4_ECHO_REQUEST: return ICMP4_ECHO_REPLY; case ICMP4_ECHO_REPLY: return ICMP4_ECHO_REQUEST; case ICMP4_TIMESTAMP: return ICMP4_TIMESTAMPREPLY; case ICMP4_TIMESTAMPREPLY: return ICMP4_TIMESTAMP; case ICMP4_INFOREQUEST: return ICMP4_INFOREPLY; case ICMP4_INFOREPLY: return ICMP4_INFOREQUEST; default: OVS_NOT_REACHED(); } } /* If 'related' is not NULL and the function is processing an ICMP * error packet, extract the l3 and l4 fields from the nested header * instead and set *related to true. If 'related' is NULL we're * already processing a nested header and no such recursion is * possible */ static inline int extract_l4_icmp(struct conn_key *key, const void *data, size_t size, bool *related) { const struct icmp_header *icmp = data; if (OVS_UNLIKELY(size < ICMP_HEADER_LEN)) { return false; } switch (icmp->icmp_type) { case ICMP4_ECHO_REQUEST: case ICMP4_ECHO_REPLY: case ICMP4_TIMESTAMP: case ICMP4_TIMESTAMPREPLY: case ICMP4_INFOREQUEST: case ICMP4_INFOREPLY: if (icmp->icmp_code != 0) { return false; } /* Separate ICMP connection: identified using id */ key->src.icmp_id = key->dst.icmp_id = icmp->icmp_fields.echo.id; key->src.icmp_type = icmp->icmp_type; key->dst.icmp_type = reverse_icmp_type(icmp->icmp_type); break; case ICMP4_DST_UNREACH: case ICMP4_TIME_EXCEEDED: case ICMP4_PARAM_PROB: case ICMP4_SOURCEQUENCH: case ICMP4_REDIRECT: { /* ICMP packet part of another connection. We should * extract the key from embedded packet header */ struct conn_key inner_key; const char *l3 = (const char *) (icmp + 1); const char *tail = (const char *) data + size; const char *l4; bool ok; if (!related) { return false; } memset(&inner_key, 0, sizeof inner_key); inner_key.dl_type = htons(ETH_TYPE_IP); ok = extract_l3_ipv4(&inner_key, l3, tail - l3, &l4, false); if (!ok) { return false; } if (inner_key.src.addr.ipv4_aligned != key->dst.addr.ipv4_aligned) { return false; } key->src = inner_key.src; key->dst = inner_key.dst; key->nw_proto = inner_key.nw_proto; ok = extract_l4(key, l4, tail - l4, NULL, l3, false); if (ok) { conn_key_reverse(key); *related = true; } return ok; } default: return false; } return true; } static uint8_t reverse_icmp6_type(uint8_t type) { switch (type) { case ICMP6_ECHO_REQUEST: return ICMP6_ECHO_REPLY; case ICMP6_ECHO_REPLY: return ICMP6_ECHO_REQUEST; default: OVS_NOT_REACHED(); } } /* If 'related' is not NULL and the function is processing an ICMP * error packet, extract the l3 and l4 fields from the nested header * instead and set *related to true. If 'related' is NULL we're * already processing a nested header and no such recursion is * possible */ static inline bool extract_l4_icmp6(struct conn_key *key, const void *data, size_t size, bool *related) { const struct icmp6_header *icmp6 = data; /* All the messages that we support need at least 4 bytes after * the header */ if (size < sizeof *icmp6 + 4) { return false; } switch (icmp6->icmp6_type) { case ICMP6_ECHO_REQUEST: case ICMP6_ECHO_REPLY: if (icmp6->icmp6_code != 0) { return false; } /* Separate ICMP connection: identified using id */ key->src.icmp_id = key->dst.icmp_id = *(ovs_be16 *) (icmp6 + 1); key->src.icmp_type = icmp6->icmp6_type; key->dst.icmp_type = reverse_icmp6_type(icmp6->icmp6_type); break; case ICMP6_DST_UNREACH: case ICMP6_PACKET_TOO_BIG: case ICMP6_TIME_EXCEEDED: case ICMP6_PARAM_PROB: { /* ICMP packet part of another connection. We should * extract the key from embedded packet header */ struct conn_key inner_key; const char *l3 = (const char *) icmp6 + 8; const char *tail = (const char *) data + size; const char *l4 = NULL; bool ok; if (!related) { return false; } memset(&inner_key, 0, sizeof inner_key); inner_key.dl_type = htons(ETH_TYPE_IPV6); ok = extract_l3_ipv6(&inner_key, l3, tail - l3, &l4); if (!ok) { return false; } /* pf doesn't do this, but it seems a good idea */ if (!ipv6_addr_equals(&inner_key.src.addr.ipv6_aligned, &key->dst.addr.ipv6_aligned)) { return false; } key->src = inner_key.src; key->dst = inner_key.dst; key->nw_proto = inner_key.nw_proto; ok = extract_l4(key, l4, tail - l4, NULL, l3, false); if (ok) { conn_key_reverse(key); *related = true; } return ok; } default: return false; } return true; } /* Extract l4 fields into 'key', which must already contain valid l3 * members. * * If 'related' is not NULL and an ICMP error packet is being * processed, the function will extract the key from the packet nested * in the ICMP payload and set '*related' to true. * * If 'related' is NULL, it means that we're already parsing a header nested * in an ICMP error. In this case, we skip checksum and length validation. */ static inline bool extract_l4(struct conn_key *key, const void *data, size_t size, bool *related, const void *l3, bool validate_checksum) { if (key->nw_proto == IPPROTO_TCP) { return (!related || check_l4_tcp(key, data, size, l3, validate_checksum)) && extract_l4_tcp(key, data, size); } else if (key->nw_proto == IPPROTO_UDP) { return (!related || check_l4_udp(key, data, size, l3, validate_checksum)) && extract_l4_udp(key, data, size); } else if (key->dl_type == htons(ETH_TYPE_IP) && key->nw_proto == IPPROTO_ICMP) { return (!related || check_l4_icmp(data, size, validate_checksum)) && extract_l4_icmp(key, data, size, related); } else if (key->dl_type == htons(ETH_TYPE_IPV6) && key->nw_proto == IPPROTO_ICMPV6) { return (!related || check_l4_icmp6(key, data, size, l3, validate_checksum)) && extract_l4_icmp6(key, data, size, related); } else { return false; } } static bool conn_key_extract(struct conntrack *ct, struct dp_packet *pkt, ovs_be16 dl_type, struct conn_lookup_ctx *ctx, uint16_t zone) { const struct eth_header *l2 = dp_packet_eth(pkt); const struct ip_header *l3 = dp_packet_l3(pkt); const char *l4 = dp_packet_l4(pkt); const char *tail = dp_packet_tail(pkt); bool ok; memset(ctx, 0, sizeof *ctx); if (!l2 || !l3 || !l4) { return false; } ctx->key.zone = zone; /* XXX In this function we parse the packet (again, it has already * gone through miniflow_extract()) for two reasons: * * 1) To extract the l3 addresses and l4 ports. * We already have the l3 and l4 headers' pointers. Extracting * the l3 addresses and the l4 ports is really cheap, since they * can be found at fixed locations. * 2) To extract the l4 type. * Extracting the l4 types, for IPv6 can be quite expensive, because * it's not at a fixed location. * * Here's a way to avoid (2) with the help of the datapath. * The datapath doesn't keep the packet's extracted flow[1], so * using that is not an option. We could use the packet's matching * megaflow, but we have to make sure that the l4 type (nw_proto) * is unwildcarded. This means either: * * a) dpif-netdev unwildcards the l4 type when a new flow is installed * if the actions contains ct(). * * b) ofproto-dpif-xlate unwildcards the l4 type when translating a ct() * action. This is already done in different actions, but it's * unnecessary for the kernel. * * --- * [1] The reasons for this are that keeping the flow increases * (slightly) the cache footprint and increases computation * time as we move the packet around. Most importantly, the flow * should be updated by the actions and this can be slow, as * we use a sparse representation (miniflow). * */ ctx->key.dl_type = dl_type; if (ctx->key.dl_type == htons(ETH_TYPE_IP)) { bool hwol_bad_l3_csum = dp_packet_ip_checksum_bad(pkt); if (hwol_bad_l3_csum) { ok = false; } else { bool hwol_good_l3_csum = dp_packet_ip_checksum_valid(pkt); /* Validate the checksum only when hwol is not supported. */ ok = extract_l3_ipv4(&ctx->key, l3, tail - (char *) l3, NULL, !hwol_good_l3_csum); } } else if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) { ok = extract_l3_ipv6(&ctx->key, l3, tail - (char *) l3, NULL); } else { ok = false; } if (ok) { bool hwol_bad_l4_csum = dp_packet_l4_checksum_bad(pkt); if (!hwol_bad_l4_csum) { bool hwol_good_l4_csum = dp_packet_l4_checksum_valid(pkt); /* Validate the checksum only when hwol is not supported. */ if (extract_l4(&ctx->key, l4, tail - l4, &ctx->icmp_related, l3, !hwol_good_l4_csum)) { ctx->hash = conn_key_hash(&ctx->key, ct->hash_basis); return true; } } } return false; } static uint32_t ct_addr_hash_add(uint32_t hash, const struct ct_addr *addr) { BUILD_ASSERT_DECL(sizeof *addr % 4 == 0); return hash_add_bytes32(hash, (const uint32_t *) addr, sizeof *addr); } static uint32_t ct_endpoint_hash_add(uint32_t hash, const struct ct_endpoint *ep) { BUILD_ASSERT_DECL(sizeof *ep % 4 == 0); return hash_add_bytes32(hash, (const uint32_t *) ep, sizeof *ep); } /* Symmetric */ static uint32_t conn_key_hash(const struct conn_key *key, uint32_t basis) { uint32_t hsrc, hdst, hash; hsrc = hdst = basis; hsrc = ct_endpoint_hash_add(hsrc, &key->src); hdst = ct_endpoint_hash_add(hdst, &key->dst); /* Even if source and destination are swapped the hash will be the same. */ hash = hsrc ^ hdst; /* Hash the rest of the key(L3 and L4 types and zone). */ hash = hash_words((uint32_t *) (&key->dst + 1), (uint32_t *) (key + 1) - (uint32_t *) (&key->dst + 1), hash); return hash_finish(hash, 0); } static void conn_key_reverse(struct conn_key *key) { struct ct_endpoint tmp; tmp = key->src; key->src = key->dst; key->dst = tmp; } static uint32_t nat_ipv6_addrs_delta(struct in6_addr *ipv6_aligned_min, struct in6_addr *ipv6_aligned_max) { uint8_t *ipv6_min_hi = &ipv6_aligned_min->s6_addr[0]; uint8_t *ipv6_min_lo = &ipv6_aligned_min->s6_addr[0] + sizeof(uint64_t); uint8_t *ipv6_max_hi = &ipv6_aligned_max->s6_addr[0]; uint8_t *ipv6_max_lo = &ipv6_aligned_max->s6_addr[0] + sizeof(uint64_t); ovs_be64 addr6_64_min_hi; ovs_be64 addr6_64_min_lo; memcpy(&addr6_64_min_hi, ipv6_min_hi, sizeof addr6_64_min_hi); memcpy(&addr6_64_min_lo, ipv6_min_lo, sizeof addr6_64_min_lo); ovs_be64 addr6_64_max_hi; ovs_be64 addr6_64_max_lo; memcpy(&addr6_64_max_hi, ipv6_max_hi, sizeof addr6_64_max_hi); memcpy(&addr6_64_max_lo, ipv6_max_lo, sizeof addr6_64_max_lo); uint64_t diff; if (addr6_64_min_hi == addr6_64_max_hi && ntohll(addr6_64_min_lo) <= ntohll(addr6_64_max_lo)) { diff = ntohll(addr6_64_max_lo) - ntohll(addr6_64_min_lo); } else if (ntohll(addr6_64_min_hi) + 1 == ntohll(addr6_64_max_hi) && ntohll(addr6_64_min_lo) > ntohll(addr6_64_max_lo)) { diff = UINT64_MAX - (ntohll(addr6_64_min_lo) - ntohll(addr6_64_max_lo) - 1); } else { /* Limit address delta supported to 32 bits or 4 billion approximately. * Possibly, this should be visible to the user through a datapath * support check, however the practical impact is probably nil. */ diff = 0xfffffffe; } if (diff > 0xfffffffe) { diff = 0xfffffffe; } return diff; } /* This function must be used in tandem with nat_ipv6_addrs_delta(), which * restricts the input parameters. */ static void nat_ipv6_addr_increment(struct in6_addr *ipv6_aligned, uint32_t increment) { uint8_t *ipv6_hi = &ipv6_aligned->s6_addr[0]; uint8_t *ipv6_lo = &ipv6_aligned->s6_addr[0] + sizeof(ovs_be64); ovs_be64 addr6_64_hi; ovs_be64 addr6_64_lo; memcpy(&addr6_64_hi, ipv6_hi, sizeof addr6_64_hi); memcpy(&addr6_64_lo, ipv6_lo, sizeof addr6_64_lo); if (UINT64_MAX - increment >= ntohll(addr6_64_lo)) { addr6_64_lo = htonll(increment + ntohll(addr6_64_lo)); } else if (addr6_64_hi != OVS_BE64_MAX) { addr6_64_hi = htonll(1 + ntohll(addr6_64_hi)); addr6_64_lo = htonll(increment - (UINT64_MAX - ntohll(addr6_64_lo) + 1)); } else { OVS_NOT_REACHED(); } memcpy(ipv6_hi, &addr6_64_hi, sizeof addr6_64_hi); memcpy(ipv6_lo, &addr6_64_lo, sizeof addr6_64_lo); return; } static uint32_t nat_range_hash(const struct conn *conn, uint32_t basis) { uint32_t hash = basis; hash = ct_addr_hash_add(hash, &conn->nat_info->min_addr); hash = ct_addr_hash_add(hash, &conn->nat_info->max_addr); hash = hash_add(hash, (conn->nat_info->max_port << 16) | conn->nat_info->min_port); hash = ct_endpoint_hash_add(hash, &conn->key.src); hash = ct_endpoint_hash_add(hash, &conn->key.dst); hash = hash_add(hash, (OVS_FORCE uint32_t) conn->key.dl_type); hash = hash_add(hash, conn->key.nw_proto); hash = hash_add(hash, conn->key.zone); /* The purpose of the second parameter is to distinguish hashes of data of * different length; our data always has the same length so there is no * value in counting. */ return hash_finish(hash, 0); } static bool nat_select_range_tuple(struct conntrack *ct, const struct conn *conn, struct conn *nat_conn) { enum { MIN_NAT_EPHEMERAL_PORT = 1024, MAX_NAT_EPHEMERAL_PORT = 65535 }; uint16_t min_port; uint16_t max_port; uint16_t first_port; uint32_t hash = nat_range_hash(conn, ct->hash_basis); if ((conn->nat_info->nat_action & NAT_ACTION_SRC) && (!(conn->nat_info->nat_action & NAT_ACTION_SRC_PORT))) { min_port = ntohs(conn->key.src.port); max_port = ntohs(conn->key.src.port); first_port = min_port; } else if ((conn->nat_info->nat_action & NAT_ACTION_DST) && (!(conn->nat_info->nat_action & NAT_ACTION_DST_PORT))) { min_port = ntohs(conn->key.dst.port); max_port = ntohs(conn->key.dst.port); first_port = min_port; } else { uint16_t deltap = conn->nat_info->max_port - conn->nat_info->min_port; uint32_t port_index = hash % (deltap + 1); first_port = conn->nat_info->min_port + port_index; min_port = conn->nat_info->min_port; max_port = conn->nat_info->max_port; } uint32_t deltaa = 0; uint32_t address_index; struct ct_addr ct_addr; memset(&ct_addr, 0, sizeof ct_addr); struct ct_addr max_ct_addr; memset(&max_ct_addr, 0, sizeof max_ct_addr); max_ct_addr = conn->nat_info->max_addr; if (conn->key.dl_type == htons(ETH_TYPE_IP)) { deltaa = ntohl(conn->nat_info->max_addr.ipv4_aligned) - ntohl(conn->nat_info->min_addr.ipv4_aligned); address_index = hash % (deltaa + 1); ct_addr.ipv4_aligned = htonl( ntohl(conn->nat_info->min_addr.ipv4_aligned) + address_index); } else { deltaa = nat_ipv6_addrs_delta(&conn->nat_info->min_addr.ipv6_aligned, &conn->nat_info->max_addr.ipv6_aligned); /* deltaa must be within 32 bits for full hash coverage. A 64 or * 128 bit hash is unnecessary and hence not used here. Most code * is kept common with V4; nat_ipv6_addrs_delta() will do the * enforcement via max_ct_addr. */ max_ct_addr = conn->nat_info->min_addr; nat_ipv6_addr_increment(&max_ct_addr.ipv6_aligned, deltaa); address_index = hash % (deltaa + 1); ct_addr.ipv6_aligned = conn->nat_info->min_addr.ipv6_aligned; nat_ipv6_addr_increment(&ct_addr.ipv6_aligned, address_index); } uint16_t port = first_port; bool all_ports_tried = false; bool original_ports_tried = false; struct ct_addr first_addr = ct_addr; while (true) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { nat_conn->rev_key.dst.addr = ct_addr; } else { nat_conn->rev_key.src.addr = ct_addr; } if ((conn->key.nw_proto == IPPROTO_ICMP) || (conn->key.nw_proto == IPPROTO_ICMPV6)) { all_ports_tried = true; } else if (conn->nat_info->nat_action & NAT_ACTION_SRC) { nat_conn->rev_key.dst.port = htons(port); } else { nat_conn->rev_key.src.port = htons(port); } bool new_insert = nat_conn_keys_insert(&ct->nat_conn_keys, nat_conn, ct->hash_basis); if (new_insert) { return true; } else if (!all_ports_tried) { if (min_port == max_port) { all_ports_tried = true; } else if (port == max_port) { port = min_port; } else { port++; } if (port == first_port) { all_ports_tried = true; } } else { if (memcmp(&ct_addr, &max_ct_addr, sizeof ct_addr)) { if (conn->key.dl_type == htons(ETH_TYPE_IP)) { ct_addr.ipv4_aligned = htonl( ntohl(ct_addr.ipv4_aligned) + 1); } else { nat_ipv6_addr_increment(&ct_addr.ipv6_aligned, 1); } } else { ct_addr = conn->nat_info->min_addr; } if (!memcmp(&ct_addr, &first_addr, sizeof ct_addr)) { if (!original_ports_tried) { original_ports_tried = true; ct_addr = conn->nat_info->min_addr; min_port = MIN_NAT_EPHEMERAL_PORT; max_port = MAX_NAT_EPHEMERAL_PORT; } else { break; } } first_port = min_port; port = first_port; all_ports_tried = false; } } return false; } /* This function must be called with the ct->resources lock taken. */ static struct nat_conn_key_node * nat_conn_keys_lookup(struct hmap *nat_conn_keys, const struct conn_key *key, uint32_t basis) { struct nat_conn_key_node *nat_conn_key_node; uint32_t nat_conn_key_hash = conn_key_hash(key, basis); HMAP_FOR_EACH_WITH_HASH (nat_conn_key_node, node, nat_conn_key_hash, nat_conn_keys) { if (!conn_key_cmp(&nat_conn_key_node->key, key)) { return nat_conn_key_node; } } return NULL; } /* This function must be called with the ct->resources lock taken. */ static bool nat_conn_keys_insert(struct hmap *nat_conn_keys, const struct conn *nat_conn, uint32_t basis) { struct nat_conn_key_node *nat_conn_key_node = nat_conn_keys_lookup(nat_conn_keys, &nat_conn->rev_key, basis); if (!nat_conn_key_node) { struct nat_conn_key_node *nat_conn_key = xzalloc(sizeof *nat_conn_key); nat_conn_key->key = nat_conn->rev_key; nat_conn_key->value = nat_conn->key; uint32_t nat_conn_key_hash = conn_key_hash(&nat_conn_key->key, basis); hmap_insert(nat_conn_keys, &nat_conn_key->node, nat_conn_key_hash); return true; } return false; } /* This function must be called with the ct->resources write lock taken. */ static void nat_conn_keys_remove(struct hmap *nat_conn_keys, const struct conn_key *key, uint32_t basis) { struct nat_conn_key_node *nat_conn_key_node; uint32_t nat_conn_key_hash = conn_key_hash(key, basis); HMAP_FOR_EACH_WITH_HASH (nat_conn_key_node, node, nat_conn_key_hash, nat_conn_keys) { if (!conn_key_cmp(&nat_conn_key_node->key, key)) { hmap_remove(nat_conn_keys, &nat_conn_key_node->node); free(nat_conn_key_node); return; } } } static void conn_key_lookup(struct conntrack_bucket *ctb, struct conn_lookup_ctx *ctx, long long now) OVS_REQUIRES(ctb->lock) { uint32_t hash = ctx->hash; struct conn *conn; ctx->conn = NULL; HMAP_FOR_EACH_WITH_HASH (conn, node, hash, &ctb->connections) { if (!conn_key_cmp(&conn->key, &ctx->key) && !conn_expired(conn, now)) { ctx->conn = conn; ctx->reply = false; break; } if (!conn_key_cmp(&conn->rev_key, &ctx->key) && !conn_expired(conn, now)) { ctx->conn = conn; ctx->reply = true; break; } } } static enum ct_update_res conn_update(struct conn *conn, struct conntrack_bucket *ctb, struct dp_packet *pkt, bool reply, long long now) { return l4_protos[conn->key.nw_proto]->conn_update(conn, ctb, pkt, reply, now); } static bool conn_expired(struct conn *conn, long long now) { if (conn->conn_type == CT_CONN_TYPE_DEFAULT) { return now >= conn->expiration; } return false; } static bool valid_new(struct dp_packet *pkt, struct conn_key *key) { return l4_protos[key->nw_proto]->valid_new(pkt); } static struct conn * new_conn(struct conntrack_bucket *ctb, struct dp_packet *pkt, struct conn_key *key, long long now) { struct conn *newconn; newconn = l4_protos[key->nw_proto]->new_conn(ctb, pkt, now); if (newconn) { newconn->key = *key; } return newconn; } static void delete_conn(struct conn *conn) { free(conn->nat_info); free(conn->alg); free(conn); } static void ct_endpoint_to_ct_dpif_inet_addr(const struct ct_addr *a, union ct_dpif_inet_addr *b, ovs_be16 dl_type) { if (dl_type == htons(ETH_TYPE_IP)) { b->ip = a->ipv4_aligned; } else if (dl_type == htons(ETH_TYPE_IPV6)){ b->in6 = a->ipv6_aligned; } } static void conn_key_to_tuple(const struct conn_key *key, struct ct_dpif_tuple *tuple) { if (key->dl_type == htons(ETH_TYPE_IP)) { tuple->l3_type = AF_INET; } else if (key->dl_type == htons(ETH_TYPE_IPV6)) { tuple->l3_type = AF_INET6; } tuple->ip_proto = key->nw_proto; ct_endpoint_to_ct_dpif_inet_addr(&key->src.addr, &tuple->src, key->dl_type); ct_endpoint_to_ct_dpif_inet_addr(&key->dst.addr, &tuple->dst, key->dl_type); if (key->nw_proto == IPPROTO_ICMP || key->nw_proto == IPPROTO_ICMPV6) { tuple->icmp_id = key->src.icmp_id; tuple->icmp_type = key->src.icmp_type; tuple->icmp_code = key->src.icmp_code; } else { tuple->src_port = key->src.port; tuple->dst_port = key->dst.port; } } static void conn_to_ct_dpif_entry(const struct conn *conn, struct ct_dpif_entry *entry, long long now, int bkt) { struct ct_l4_proto *class; long long expiration; memset(entry, 0, sizeof *entry); conn_key_to_tuple(&conn->key, &entry->tuple_orig); conn_key_to_tuple(&conn->rev_key, &entry->tuple_reply); entry->zone = conn->key.zone; entry->mark = conn->mark; memcpy(&entry->labels, &conn->label, sizeof entry->labels); /* Not implemented yet */ entry->timestamp.start = 0; entry->timestamp.stop = 0; expiration = conn->expiration - now; entry->timeout = (expiration > 0) ? expiration / 1000 : 0; class = l4_protos[conn->key.nw_proto]; if (class->conn_get_protoinfo) { class->conn_get_protoinfo(conn, &entry->protoinfo); } entry->bkt = bkt; if (conn->alg) { /* Caller is responsible for freeing. */ entry->helper.name = xstrdup(conn->alg); } } int conntrack_dump_start(struct conntrack *ct, struct conntrack_dump *dump, const uint16_t *pzone, int *ptot_bkts) { memset(dump, 0, sizeof(*dump)); if (pzone) { dump->zone = *pzone; dump->filter_zone = true; } dump->ct = ct; *ptot_bkts = CONNTRACK_BUCKETS; return 0; } int conntrack_dump_next(struct conntrack_dump *dump, struct ct_dpif_entry *entry) { struct conntrack *ct = dump->ct; long long now = time_msec(); while (dump->bucket < CONNTRACK_BUCKETS) { struct hmap_node *node; ct_lock_lock(&ct->buckets[dump->bucket].lock); for (;;) { struct conn *conn; node = hmap_at_position(&ct->buckets[dump->bucket].connections, &dump->bucket_pos); if (!node) { break; } INIT_CONTAINER(conn, node, node); if ((!dump->filter_zone || conn->key.zone == dump->zone) && (conn->conn_type != CT_CONN_TYPE_UN_NAT)) { conn_to_ct_dpif_entry(conn, entry, now, dump->bucket); break; } /* Else continue, until we find an entry in the appropriate zone * or the bucket has been scanned completely. */ } ct_lock_unlock(&ct->buckets[dump->bucket].lock); if (!node) { memset(&dump->bucket_pos, 0, sizeof dump->bucket_pos); dump->bucket++; } else { return 0; } } return EOF; } int conntrack_dump_done(struct conntrack_dump *dump OVS_UNUSED) { return 0; } int conntrack_flush(struct conntrack *ct, const uint16_t *zone) { unsigned i; for (i = 0; i < CONNTRACK_BUCKETS; i++) { struct conn *conn, *next; ct_lock_lock(&ct->buckets[i].lock); HMAP_FOR_EACH_SAFE (conn, next, node, &ct->buckets[i].connections) { if ((!zone || *zone == conn->key.zone) && (conn->conn_type == CT_CONN_TYPE_DEFAULT)) { conn_clean(ct, conn, &ct->buckets[i]); } } ct_lock_unlock(&ct->buckets[i].lock); } ct_rwlock_wrlock(&ct->resources_lock); struct alg_exp_node *alg_exp_node, *alg_exp_node_next; HMAP_FOR_EACH_SAFE (alg_exp_node, alg_exp_node_next, node, &ct->alg_expectations) { if (!zone || *zone == alg_exp_node->key.zone) { ovs_list_remove(&alg_exp_node->exp_node); hmap_remove(&ct->alg_expectations, &alg_exp_node->node); free(alg_exp_node); } } ct_rwlock_unlock(&ct->resources_lock); return 0; } /* This function must be called with the ct->resources read lock taken. */ static struct alg_exp_node * expectation_lookup(struct hmap *alg_expectations, const struct conn_key *key, uint32_t basis) { struct conn_key check_key = *key; check_key.src.port = ALG_WC_SRC_PORT; struct alg_exp_node *alg_exp_node; uint32_t alg_exp_conn_key_hash = conn_key_hash(&check_key, basis); HMAP_FOR_EACH_WITH_HASH (alg_exp_node, node, alg_exp_conn_key_hash, alg_expectations) { if (!conn_key_cmp(&alg_exp_node->key, &check_key)) { return alg_exp_node; } } return NULL; } static void expectation_create(struct conntrack *ct, ovs_be16 dst_port, const long long now, enum ct_alg_mode mode, const struct conn *master_conn) { struct ct_addr src_addr; struct ct_addr dst_addr; struct ct_addr alg_nat_repl_addr; switch (mode) { case CT_FTP_MODE_ACTIVE: case CT_TFTP_MODE: src_addr = master_conn->rev_key.src.addr; dst_addr = master_conn->rev_key.dst.addr; alg_nat_repl_addr = master_conn->key.src.addr; break; case CT_FTP_MODE_PASSIVE: src_addr = master_conn->key.src.addr; dst_addr = master_conn->key.dst.addr; alg_nat_repl_addr = master_conn->rev_key.dst.addr; break; default: OVS_NOT_REACHED(); } struct alg_exp_node *alg_exp_node = xzalloc(sizeof *alg_exp_node); alg_exp_node->key.dl_type = master_conn->key.dl_type; alg_exp_node->key.nw_proto = master_conn->key.nw_proto; alg_exp_node->key.zone = master_conn->key.zone; alg_exp_node->key.src.addr = src_addr; alg_exp_node->key.dst.addr = dst_addr; alg_exp_node->key.src.port = ALG_WC_SRC_PORT; alg_exp_node->key.dst.port = dst_port; alg_exp_node->master_mark = master_conn->mark; alg_exp_node->master_label = master_conn->label; alg_exp_node->master_key = master_conn->key; alg_exp_node->passive_mode = mode == CT_FTP_MODE_PASSIVE; /* Take the write lock here because it is almost 100% * likely that the lookup will fail and * expectation_create() will be called below. */ ct_rwlock_wrlock(&ct->resources_lock); struct alg_exp_node *alg_exp = expectation_lookup( &ct->alg_expectations, &alg_exp_node->key, ct->hash_basis); if (alg_exp) { free(alg_exp_node); ct_rwlock_unlock(&ct->resources_lock); return; } alg_exp_node->alg_nat_repl_addr = alg_nat_repl_addr; uint32_t alg_exp_conn_key_hash = conn_key_hash(&alg_exp_node->key, ct->hash_basis); hmap_insert(&ct->alg_expectations, &alg_exp_node->node, alg_exp_conn_key_hash); alg_exp_init_expiration(ct, alg_exp_node, now); ct_rwlock_unlock(&ct->resources_lock); } static uint8_t get_v4_byte_be(ovs_be32 v4_addr, uint8_t index) { uint8_t *byte_ptr = (OVS_FORCE uint8_t *) &v4_addr; return byte_ptr[index]; } static void replace_substring(char *substr, uint8_t substr_size, uint8_t total_size, char *rep_str, uint8_t rep_str_size) { memmove(substr + rep_str_size, substr + substr_size, total_size - substr_size); memcpy(substr, rep_str, rep_str_size); } /* Replace IPV4 address in FTP message with NATed address. */ static int repl_ftp_v4_addr(struct dp_packet *pkt, ovs_be32 v4_addr_rep, char *ftp_data_start, size_t addr_offset_from_ftp_data_start) { enum { MAX_FTP_V4_NAT_DELTA = 8 }; /* Do conservative check for pathological MTU usage. */ uint32_t orig_used_size = dp_packet_size(pkt); uint16_t allocated_size = dp_packet_get_allocated(pkt); if (orig_used_size + MAX_FTP_V4_NAT_DELTA > allocated_size) { static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5); VLOG_WARN_RL(&rl, "Unsupported effective MTU %u used with FTP", allocated_size); return 0; } size_t remain_size = tcp_payload_length(pkt) - addr_offset_from_ftp_data_start; int overall_delta = 0; char *byte_str = ftp_data_start + addr_offset_from_ftp_data_start; /* Replace the existing IPv4 address by the new one. */ for (uint8_t i = 0; i < 4; i++) { /* Find the end of the string for this octet. */ char *next_delim = memchr(byte_str, ',', 4); ovs_assert(next_delim); int substr_size = next_delim - byte_str; remain_size -= substr_size; /* Compose the new string for this octet, and replace it. */ char rep_str[4]; uint8_t rep_byte = get_v4_byte_be(v4_addr_rep, i); int replace_size = sprintf(rep_str, "%d", rep_byte); replace_substring(byte_str, substr_size, remain_size, rep_str, replace_size); overall_delta += replace_size - substr_size; /* Advance past the octet and the following comma. */ byte_str += replace_size + 1; } dp_packet_set_size(pkt, orig_used_size + overall_delta); return overall_delta; } static char * skip_non_digits(char *str) { while (!isdigit(*str) && *str != 0) { str++; } return str; } static char * terminate_number_str(char *str, uint8_t max_digits) { uint8_t digits_found = 0; while (isdigit(*str) && digits_found <= max_digits) { str++; digits_found++; } *str = 0; return str; } static void get_ftp_ctl_msg(struct dp_packet *pkt, char *ftp_msg) { struct tcp_header *th = dp_packet_l4(pkt); char *tcp_hdr = (char *) th; uint32_t tcp_payload_len = tcp_payload_length(pkt); size_t tcp_payload_of_interest = MIN(tcp_payload_len, LARGEST_FTP_MSG_OF_INTEREST); size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4; ovs_strlcpy(ftp_msg, tcp_hdr + tcp_hdr_len, tcp_payload_of_interest); } static enum ftp_ctl_pkt detect_ftp_ctl_type(const struct conn_lookup_ctx *ctx, struct dp_packet *pkt) { char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0}; get_ftp_ctl_msg(pkt, ftp_msg); if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) { if (strncasecmp(ftp_msg, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD)) && !strcasestr(ftp_msg, FTP_EPSV_REPLY)) { return CT_FTP_CTL_OTHER; } } else { if (strncasecmp(ftp_msg, FTP_PORT_CMD, strlen(FTP_PORT_CMD)) && strncasecmp(ftp_msg, FTP_PASV_REPLY_CODE, strlen(FTP_PASV_REPLY_CODE))) { return CT_FTP_CTL_OTHER; } } return CT_FTP_CTL_INTEREST; } static enum ftp_ctl_pkt process_ftp_ctl_v4(struct conntrack *ct, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, ovs_be32 *v4_addr_rep, char **ftp_data_v4_start, size_t *addr_offset_from_ftp_data_start) { struct tcp_header *th = dp_packet_l4(pkt); size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4; char *tcp_hdr = (char *) th; *ftp_data_v4_start = tcp_hdr + tcp_hdr_len; char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0}; get_ftp_ctl_msg(pkt, ftp_msg); char *ftp = ftp_msg; enum ct_alg_mode mode; if (!strncasecmp(ftp, FTP_PORT_CMD, strlen(FTP_PORT_CMD))) { ftp = ftp_msg + strlen(FTP_PORT_CMD); mode = CT_FTP_MODE_ACTIVE; } else { ftp = ftp_msg + strlen(FTP_PASV_REPLY_CODE); mode = CT_FTP_MODE_PASSIVE; } /* Find first space. */ ftp = strchr(ftp, ' '); if (!ftp) { return CT_FTP_CTL_INVALID; } /* Find the first digit, after space. */ ftp = skip_non_digits(ftp); if (*ftp == 0) { return CT_FTP_CTL_INVALID; } char *ip_addr_start = ftp; *addr_offset_from_ftp_data_start = ip_addr_start - ftp_msg; uint8_t comma_count = 0; while (comma_count < 4 && *ftp) { if (*ftp == ',') { comma_count++; if (comma_count == 4) { *ftp = 0; } else { *ftp = '.'; } } ftp++; } if (comma_count != 4) { return CT_FTP_CTL_INVALID; } struct in_addr ip_addr; int rc2 = inet_pton(AF_INET, ip_addr_start, &ip_addr); if (rc2 != 1) { return CT_FTP_CTL_INVALID; } char *save_ftp = ftp; ftp = terminate_number_str(ftp, MAX_FTP_PORT_DGTS); if (!ftp) { return CT_FTP_CTL_INVALID; } int value; if (!str_to_int(save_ftp, 10, &value)) { return CT_FTP_CTL_INVALID; } /* This is derived from the L4 port maximum is 65535. */ if (value > 255) { return CT_FTP_CTL_INVALID; } uint16_t port_hs = value; port_hs <<= 8; /* Skip over comma. */ ftp++; save_ftp = ftp; bool digit_found = false; while (isdigit(*ftp)) { ftp++; digit_found = true; } if (!digit_found) { return CT_FTP_CTL_INVALID; } *ftp = 0; if (!str_to_int(save_ftp, 10, &value)) { return CT_FTP_CTL_INVALID; } if (value > 255) { return CT_FTP_CTL_INVALID; } uint16_t port_lo_hs = value; if (65535 - port_hs < port_lo_hs) { return CT_FTP_CTL_INVALID; } port_hs |= port_lo_hs; ovs_be16 port = htons(port_hs); ovs_be32 conn_ipv4_addr; switch (mode) { case CT_FTP_MODE_ACTIVE: *v4_addr_rep = conn_for_expectation->rev_key.dst.addr.ipv4_aligned; conn_ipv4_addr = conn_for_expectation->key.src.addr.ipv4_aligned; break; case CT_FTP_MODE_PASSIVE: *v4_addr_rep = conn_for_expectation->key.dst.addr.ipv4_aligned; conn_ipv4_addr = conn_for_expectation->rev_key.src.addr.ipv4_aligned; break; case CT_TFTP_MODE: default: OVS_NOT_REACHED(); } ovs_be32 ftp_ipv4_addr; ftp_ipv4_addr = ip_addr.s_addr; /* Although most servers will block this exploit, there may be some * less well managed. */ if (ftp_ipv4_addr != conn_ipv4_addr && ftp_ipv4_addr != *v4_addr_rep) { return CT_FTP_CTL_INVALID; } expectation_create(ct, port, now, mode, conn_for_expectation); return CT_FTP_CTL_INTEREST; } static char * skip_ipv6_digits(char *str) { while (isxdigit(*str) || *str == ':' || *str == '.') { str++; } return str; } static enum ftp_ctl_pkt process_ftp_ctl_v6(struct conntrack *ct, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, struct ct_addr *v6_addr_rep, char **ftp_data_start, size_t *addr_offset_from_ftp_data_start, size_t *addr_size, enum ct_alg_mode *mode) { struct tcp_header *th = dp_packet_l4(pkt); size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4; char *tcp_hdr = (char *) th; char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0}; get_ftp_ctl_msg(pkt, ftp_msg); *ftp_data_start = tcp_hdr + tcp_hdr_len; char *ftp = ftp_msg; struct in6_addr ip6_addr; if (!strncasecmp(ftp, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD))) { ftp = ftp_msg + strlen(FTP_EPRT_CMD); ftp = skip_non_digits(ftp); if (*ftp != FTP_AF_V6 || isdigit(ftp[1])) { return CT_FTP_CTL_INVALID; } /* Jump over delimiter. */ ftp += 2; char *ip_addr_start = ftp; memset(&ip6_addr, 0, sizeof ip6_addr); *addr_offset_from_ftp_data_start = ip_addr_start - ftp_msg; ftp = skip_ipv6_digits(ftp); *ftp = 0; *addr_size = ftp - ip_addr_start; int rc2 = inet_pton(AF_INET6, ip_addr_start, &ip6_addr); if (rc2 != 1) { return CT_FTP_CTL_INVALID; } ftp++; *mode = CT_FTP_MODE_ACTIVE; } else { ftp = ftp_msg + strcspn(ftp_msg, "("); ftp = skip_non_digits(ftp); if (!isdigit(*ftp)) { return CT_FTP_CTL_INVALID; } /* Not used for passive mode. */ *addr_offset_from_ftp_data_start = 0; *addr_size = 0; *mode = CT_FTP_MODE_PASSIVE; } char *save_ftp = ftp; ftp = terminate_number_str(ftp, MAX_EXT_FTP_PORT_DGTS); if (!ftp) { return CT_FTP_CTL_INVALID; } int value; if (!str_to_int(save_ftp, 10, &value)) { return CT_FTP_CTL_INVALID; } if (value > CT_MAX_L4_PORT) { return CT_FTP_CTL_INVALID; } uint16_t port_hs = value; ovs_be16 port = htons(port_hs); switch (*mode) { case CT_FTP_MODE_ACTIVE: *v6_addr_rep = conn_for_expectation->rev_key.dst.addr; /* Although most servers will block this exploit, there may be some * less well managed. */ if (memcmp(&ip6_addr, &v6_addr_rep->ipv6_aligned, sizeof ip6_addr) && memcmp(&ip6_addr, &conn_for_expectation->key.src.addr.ipv6_aligned, sizeof ip6_addr)) { return CT_FTP_CTL_INVALID; } break; case CT_FTP_MODE_PASSIVE: *v6_addr_rep = conn_for_expectation->key.dst.addr; break; case CT_TFTP_MODE: default: OVS_NOT_REACHED(); } expectation_create(ct, port, now, *mode, conn_for_expectation); return CT_FTP_CTL_INTEREST; } static int repl_ftp_v6_addr(struct dp_packet *pkt, struct ct_addr v6_addr_rep, char *ftp_data_start, size_t addr_offset_from_ftp_data_start, size_t addr_size, enum ct_alg_mode mode) { /* This is slightly bigger than really possible. */ enum { MAX_FTP_V6_NAT_DELTA = 45 }; if (mode == CT_FTP_MODE_PASSIVE) { return 0; } /* Do conservative check for pathological MTU usage. */ uint32_t orig_used_size = dp_packet_size(pkt); uint16_t allocated_size = dp_packet_get_allocated(pkt); if (orig_used_size + MAX_FTP_V6_NAT_DELTA > allocated_size) { static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5); VLOG_WARN_RL(&rl, "Unsupported effective MTU %u used with FTP", allocated_size); return 0; } const char *rc; char v6_addr_str[IPV6_SCAN_LEN] = {0}; rc = inet_ntop(AF_INET6, &v6_addr_rep.ipv6_aligned, v6_addr_str, IPV6_SCAN_LEN - 1); ovs_assert(rc != NULL); size_t replace_addr_size = strlen(v6_addr_str); size_t remain_size = tcp_payload_length(pkt) - addr_offset_from_ftp_data_start; char *pkt_addr_str = ftp_data_start + addr_offset_from_ftp_data_start; replace_substring(pkt_addr_str, addr_size, remain_size, v6_addr_str, replace_addr_size); int overall_delta = (int) replace_addr_size - (int) addr_size; dp_packet_set_size(pkt, orig_used_size + overall_delta); return overall_delta; } static void handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, const struct conn *conn_for_expectation, long long now, enum ftp_ctl_pkt ftp_ctl, bool nat) { struct ip_header *l3_hdr = dp_packet_l3(pkt); ovs_be32 v4_addr_rep = 0; struct ct_addr v6_addr_rep; size_t addr_offset_from_ftp_data_start; size_t addr_size = 0; char *ftp_data_start; bool do_seq_skew_adj = true; enum ct_alg_mode mode = CT_FTP_MODE_ACTIVE; if (detect_ftp_ctl_type(ctx, pkt) != ftp_ctl) { return; } if (!nat || !conn_for_expectation->seq_skew) { do_seq_skew_adj = false; } struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt); int64_t seq_skew = 0; if (ftp_ctl == CT_FTP_CTL_OTHER) { seq_skew = conn_for_expectation->seq_skew; } else if (ftp_ctl == CT_FTP_CTL_INTEREST) { enum ftp_ctl_pkt rc; if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) { rc = process_ftp_ctl_v6(ct, pkt, conn_for_expectation, now, &v6_addr_rep, &ftp_data_start, &addr_offset_from_ftp_data_start, &addr_size, &mode); } else { rc = process_ftp_ctl_v4(ct, pkt, conn_for_expectation, now, &v4_addr_rep, &ftp_data_start, &addr_offset_from_ftp_data_start); } if (rc == CT_FTP_CTL_INVALID) { static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5); VLOG_WARN_RL(&rl, "Invalid FTP control packet format"); pkt->md.ct_state |= CS_TRACKED | CS_INVALID; return; } else if (rc == CT_FTP_CTL_INTEREST) { uint16_t ip_len; if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) { seq_skew = repl_ftp_v6_addr(pkt, v6_addr_rep, ftp_data_start, addr_offset_from_ftp_data_start, addr_size, mode); if (seq_skew) { ip_len = ntohs(nh6->ip6_ctlun.ip6_un1.ip6_un1_plen); ip_len += seq_skew; nh6->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(ip_len); conn_seq_skew_set(ct, &conn_for_expectation->key, now, seq_skew, ctx->reply); } } else { seq_skew = repl_ftp_v4_addr(pkt, v4_addr_rep, ftp_data_start, addr_offset_from_ftp_data_start); ip_len = ntohs(l3_hdr->ip_tot_len); if (seq_skew) { ip_len += seq_skew; l3_hdr->ip_csum = recalc_csum16(l3_hdr->ip_csum, l3_hdr->ip_tot_len, htons(ip_len)); l3_hdr->ip_tot_len = htons(ip_len); conn_seq_skew_set(ct, &conn_for_expectation->key, now, seq_skew, ctx->reply); } } } else { OVS_NOT_REACHED(); } } else { OVS_NOT_REACHED(); } struct tcp_header *th = dp_packet_l4(pkt); if (do_seq_skew_adj && seq_skew != 0) { if (ctx->reply != conn_for_expectation->seq_skew_dir) { uint32_t tcp_ack = ntohl(get_16aligned_be32(&th->tcp_ack)); if ((seq_skew > 0) && (tcp_ack < seq_skew)) { /* Should not be possible; will be marked invalid. */ tcp_ack = 0; } else if ((seq_skew < 0) && (UINT32_MAX - tcp_ack < -seq_skew)) { tcp_ack = (-seq_skew) - (UINT32_MAX - tcp_ack); } else { tcp_ack -= seq_skew; } ovs_be32 new_tcp_ack = htonl(tcp_ack); put_16aligned_be32(&th->tcp_ack, new_tcp_ack); } else { uint32_t tcp_seq = ntohl(get_16aligned_be32(&th->tcp_seq)); if ((seq_skew > 0) && (UINT32_MAX - tcp_seq < seq_skew)) { tcp_seq = seq_skew - (UINT32_MAX - tcp_seq); } else if ((seq_skew < 0) && (tcp_seq < -seq_skew)) { /* Should not be possible; will be marked invalid. */ tcp_seq = 0; } else { tcp_seq += seq_skew; } ovs_be32 new_tcp_seq = htonl(tcp_seq); put_16aligned_be32(&th->tcp_seq, new_tcp_seq); } } const char *tail = dp_packet_tail(pkt); uint8_t pad = dp_packet_l2_pad_size(pkt); th->tcp_csum = 0; uint32_t tcp_csum; if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) { tcp_csum = packet_csum_pseudoheader6(nh6); } else { tcp_csum = packet_csum_pseudoheader(l3_hdr); } th->tcp_csum = csum_finish( csum_continue(tcp_csum, th, tail - (char *) th - pad)); return; } static void handle_tftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx OVS_UNUSED, struct dp_packet *pkt OVS_UNUSED, const struct conn *conn_for_expectation, long long now, enum ftp_ctl_pkt ftp_ctl OVS_UNUSED, bool nat OVS_UNUSED) { expectation_create(ct, conn_for_expectation->key.src.port, now, CT_TFTP_MODE, conn_for_expectation); return; }