diff options
| -rw-r--r-- | NEWS | 3 | ||||
| -rw-r--r-- | lib/conntrack-private.h | 33 | ||||
| -rw-r--r-- | lib/conntrack.c | 332 | ||||
| -rw-r--r-- | lib/ovs-actions.xml | 3 | ||||
| -rw-r--r-- | tests/system-userspace-macros.at | 8 |
5 files changed, 248 insertions, 131 deletions
@@ -17,6 +17,9 @@ Post-v2.15.0 cases, e.g if all PMD threads are running on the same NUMA node. * Userspace datapath now supports up to 2^18 meters. * Added support for systems with non-contiguous NUMA nodes and core ids. + * Added all-zero IP SNAT handling to conntrack. In case of collision, + using ct(src=0.0.0.0), the source port will be replaced with another + non-colliding port in the ephemeral range (1024, 65535). - ovs-ctl: * New option '--no-record-hostname' to disable hostname configuration in ovsdb on startup. diff --git a/lib/conntrack-private.h b/lib/conntrack-private.h index e8332bdba..169ace588 100644 --- a/lib/conntrack-private.h +++ b/lib/conntrack-private.h @@ -148,6 +148,39 @@ enum ct_update_res { CT_TIMEOUT(ICMP_FIRST) \ CT_TIMEOUT(ICMP_REPLY) +#define NAT_ACTION_SNAT_ALL (NAT_ACTION_SRC | NAT_ACTION_SRC_PORT) +#define NAT_ACTION_DNAT_ALL (NAT_ACTION_DST | NAT_ACTION_DST_PORT) + +enum ct_ephemeral_range { + MIN_NAT_EPHEMERAL_PORT = 1024, + MAX_NAT_EPHEMERAL_PORT = 65535 +}; + +#define IN_RANGE(curr, min, max) \ + (curr >= min && curr <= max) + +#define NEXT_PORT_IN_RANGE(curr, min, max) \ + (curr = (!IN_RANGE(curr, min, max) || curr == max) ? min : curr + 1) + +/* If the current port is out of range increase the attempts by + * one so that in the worst case scenario the current out of + * range port plus all the in-range ports get tested. + * Note that curr can be an out of range port only in case of + * source port (SNAT with port range unspecified or DNAT), + * furthermore the source port in the packet has to be less than + * MIN_NAT_EPHEMERAL_PORT. */ +#define N_PORT_ATTEMPTS(curr, min, max) \ + ((!IN_RANGE(curr, min, max)) ? (max - min) + 2 : (max - min) + 1) + +/* Loose in-range check, the first curr port can be any port out of + * the range. */ +#define FOR_EACH_PORT_IN_RANGE__(curr, min, max, INAME) \ + for (uint16_t INAME = N_PORT_ATTEMPTS(curr, min, max); \ + INAME > 0; INAME--, NEXT_PORT_IN_RANGE(curr, min, max)) + +#define FOR_EACH_PORT_IN_RANGE(curr, min, max) \ + FOR_EACH_PORT_IN_RANGE__(curr, min, max, OVS_JOIN(idx, __COUNTER__)) + enum ct_timeout { #define CT_TIMEOUT(NAME) CT_TM_##NAME, CT_TIMEOUTS diff --git a/lib/conntrack.c b/lib/conntrack.c index 0f66fa3b5..508116a29 100644 --- a/lib/conntrack.c +++ b/lib/conntrack.c @@ -110,8 +110,8 @@ static void set_label(struct dp_packet *, struct conn *, static void *clean_thread_main(void *f_); static bool -nat_select_range_tuple(struct conntrack *ct, const struct conn *conn, - struct conn *nat_conn); +nat_get_unique_tuple(struct conntrack *ct, const struct conn *conn, + struct conn *nat_conn); static uint8_t reverse_icmp_type(uint8_t type); @@ -730,11 +730,11 @@ pat_packet(struct dp_packet *pkt, const struct conn *conn) } } 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); + packet_set_tcp_port(pkt, conn->rev_key.dst.port, + 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); + packet_set_udp_port(pkt, conn->rev_key.dst.port, + conn->rev_key.src.port); } } } @@ -788,11 +788,9 @@ un_pat_packet(struct dp_packet *pkt, const struct conn *conn) } } 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); + packet_set_tcp_port(pkt, conn->key.dst.port, 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, conn->key.dst.port, uh->udp_dst); + packet_set_udp_port(pkt, conn->key.dst.port, conn->key.src.port); } } } @@ -812,12 +810,10 @@ reverse_pat_packet(struct dp_packet *pkt, const struct conn *conn) } } 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, + packet_set_tcp_port(pkt, conn->key.src.port, 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, + packet_set_udp_port(pkt, conn->key.src.port, conn->key.dst.port); } } @@ -1031,14 +1027,14 @@ conn_not_found(struct conntrack *ct, struct dp_packet *pkt, } } else { memcpy(nat_conn, nc, sizeof *nat_conn); - bool nat_res = nat_select_range_tuple(ct, nc, nat_conn); + bool nat_res = nat_get_unique_tuple(ct, nc, nat_conn); if (!nat_res) { goto nat_res_exhaustion; } /* Update nc with nat adjustments made to nat_conn by - * nat_select_range_tuple(). */ + * nat_get_unique_tuple(). */ memcpy(nc, nat_conn, sizeof *nc); } @@ -2252,130 +2248,218 @@ nat_range_hash(const struct conn *conn, uint32_t basis) 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); +/* Ports are stored in host byte order for convenience. */ +static void +set_sport_range(struct nat_action_info_t *ni, const struct conn_key *k, + uint32_t hash, uint16_t *curr, uint16_t *min, + uint16_t *max) +{ + if (((ni->nat_action & NAT_ACTION_SNAT_ALL) == NAT_ACTION_SRC) || + ((ni->nat_action & NAT_ACTION_DST))) { + *curr = ntohs(k->src.port); + *min = MIN_NAT_EPHEMERAL_PORT; + *max = MAX_NAT_EPHEMERAL_PORT; + } else { + *min = ni->min_port; + *max = ni->max_port; + *curr = *min + (hash % ((*max - *min) + 1)); + } +} - 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; +static void +set_dport_range(struct nat_action_info_t *ni, const struct conn_key *k, + uint32_t hash, uint16_t *curr, uint16_t *min, + uint16_t *max) +{ + if (ni->nat_action & NAT_ACTION_DST_PORT) { + *min = ni->min_port; + *max = ni->max_port; + *curr = *min + (hash % ((*max - *min) + 1)); } 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; + *curr = ntohs(k->dst.port); + *min = *max = *curr; } +} - uint32_t deltaa = 0; - uint32_t address_index; - union ct_addr ct_addr; - memset(&ct_addr, 0, sizeof ct_addr); - union ct_addr max_ct_addr; - memset(&max_ct_addr, 0, sizeof max_ct_addr); - max_ct_addr = conn->nat_info->max_addr; +/* Gets the initial in range address based on the hash. + * Addresses are kept in network order. */ +static void +get_addr_in_range(union ct_addr *min, union ct_addr *max, + union ct_addr *curr, uint32_t hash, bool ipv4) +{ + uint32_t offt, range; - if (conn->key.dl_type == htons(ETH_TYPE_IP)) { - deltaa = ntohl(conn->nat_info->max_addr.ipv4) - - ntohl(conn->nat_info->min_addr.ipv4); - address_index = hash % (deltaa + 1); - ct_addr.ipv4 = htonl( - ntohl(conn->nat_info->min_addr.ipv4) + address_index); + if (ipv4) { + range = (ntohl(max->ipv4) - ntohl(min->ipv4)) + 1; + offt = hash % range; + curr->ipv4 = htonl(ntohl(min->ipv4) + offt); } else { - deltaa = nat_ipv6_addrs_delta(&conn->nat_info->min_addr.ipv6, - &conn->nat_info->max_addr.ipv6); - /* deltaa must be within 32 bits for full hash coverage. A 64 or + range = nat_ipv6_addrs_delta(&min->ipv6, &max->ipv6) + 1; + /* Range 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, deltaa); - address_index = hash % (deltaa + 1); - ct_addr.ipv6 = conn->nat_info->min_addr.ipv6; - nat_ipv6_addr_increment(&ct_addr.ipv6, address_index); - } - - uint16_t port = first_port; - bool all_ports_tried = false; - /* For DNAT or for specified port ranges, we don't use ephemeral ports. */ - bool ephemeral_ports_tried - = conn->nat_info->nat_action & NAT_ACTION_DST || - conn->nat_info->nat_action & NAT_ACTION_SRC_PORT - ? true : false; - union ct_addr first_addr = ct_addr; - bool pat_enabled = conn->key.nw_proto == IPPROTO_TCP || - conn->key.nw_proto == IPPROTO_UDP; - - while (true) { + offt = hash % range; + curr->ipv6 = min->ipv6; + nat_ipv6_addr_increment(&curr->ipv6, offt); + } +} + +static void +get_initial_addr(const struct conn *conn, union ct_addr *min, + union ct_addr *max, union ct_addr *curr, + uint32_t hash, bool ipv4) +{ + const union ct_addr zero_ip = {0}; + + /* All-zero case. */ + if (!memcmp(min, &zero_ip, sizeof *min)) { if (conn->nat_info->nat_action & NAT_ACTION_SRC) { - nat_conn->rev_key.dst.addr = ct_addr; - if (pat_enabled) { - nat_conn->rev_key.dst.port = htons(port); - } - } else { - nat_conn->rev_key.src.addr = ct_addr; - if (pat_enabled) { - nat_conn->rev_key.src.port = htons(port); - } + *curr = conn->key.src.addr; + } else if (conn->nat_info->nat_action & NAT_ACTION_DST) { + *curr = conn->key.dst.addr; + } + } else { + get_addr_in_range(min, max, curr, hash, ipv4); + } +} + +static void +store_addr_to_key(union ct_addr *addr, struct conn_key *key, + uint16_t action) +{ + if (action & NAT_ACTION_SRC) { + key->dst.addr = *addr; + } else { + key->src.addr = *addr; + } +} + +static void +next_addr_in_range(union ct_addr *curr, union ct_addr *min, + union ct_addr *max, bool ipv4) +{ + if (ipv4) { + /* This check could be unified with IPv6, but let's avoid + * an unneeded memcmp() in case of IPv4. */ + if (min->ipv4 == max->ipv4) { + return; + } + + curr->ipv4 = (curr->ipv4 == max->ipv4) ? min->ipv4 + : htonl(ntohl(curr->ipv4) + 1); + } else { + if (!memcmp(min, max, sizeof *min)) { + return; + } + + if (!memcmp(curr, max, sizeof *curr)) { + *curr = *min; + return; } - bool found = conn_lookup(ct, &nat_conn->rev_key, time_msec(), NULL, - NULL); - if (!found) { + nat_ipv6_addr_increment(&curr->ipv6, 1); + } +} + +static bool +next_addr_in_range_guarded(union ct_addr *curr, union ct_addr *min, + union ct_addr *max, union ct_addr *guard, + bool ipv4) +{ + bool exhausted; + + next_addr_in_range(curr, min, max, ipv4); + + if (ipv4) { + exhausted = (curr->ipv4 == guard->ipv4); + } else { + exhausted = !memcmp(curr, guard, sizeof *curr); + } + + return exhausted; +} + +/* This function tries to get a unique tuple. + * Every iteration checks that the reverse tuple doesn't + * collide with any existing one. + * + * In case of SNAT: + * - For each src IP address in the range (if any). + * - Try to find a source port in range (if any). + * - If no port range exists, use the whole + * ephemeral range (after testing the port + * used by the sender), otherwise use the + * specified range. + * + * In case of DNAT: + * - For each dst IP address in the range (if any). + * - For each dport in range (if any). + * - Try to find a source port in the ephemeral range + * (after testing the port used by the sender). + * + * If none can be found, return exhaustion to the caller. */ +static bool +nat_get_unique_tuple(struct conntrack *ct, const struct conn *conn, + struct conn *nat_conn) +{ + union ct_addr min_addr = {0}, max_addr = {0}, curr_addr = {0}, + guard_addr = {0}; + uint32_t hash = nat_range_hash(conn, ct->hash_basis); + bool pat_proto = conn->key.nw_proto == IPPROTO_TCP || + conn->key.nw_proto == IPPROTO_UDP; + uint16_t min_dport, max_dport, curr_dport; + uint16_t min_sport, max_sport, curr_sport; + + min_addr = conn->nat_info->min_addr; + max_addr = conn->nat_info->max_addr; + + get_initial_addr(conn, &min_addr, &max_addr, &curr_addr, hash, + (conn->key.dl_type == htons(ETH_TYPE_IP))); + + /* Save the address we started from so that + * we can stop once we reach it. */ + guard_addr = curr_addr; + + set_sport_range(conn->nat_info, &conn->key, hash, &curr_sport, + &min_sport, &max_sport); + set_dport_range(conn->nat_info, &conn->key, hash, &curr_dport, + &min_dport, &max_dport); + +another_round: + store_addr_to_key(&curr_addr, &nat_conn->rev_key, + conn->nat_info->nat_action); + + if (!pat_proto) { + if (!conn_lookup(ct, &nat_conn->rev_key, + time_msec(), NULL, NULL)) { return true; - } else if (pat_enabled && !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 = htonl(ntohl(ct_addr.ipv4) + 1); - } else { - nat_ipv6_addr_increment(&ct_addr.ipv6, 1); - } - } else { - ct_addr = conn->nat_info->min_addr; - } - if (!memcmp(&ct_addr, &first_addr, sizeof ct_addr)) { - if (pat_enabled && !ephemeral_ports_tried) { - ephemeral_ports_tried = true; - ct_addr = conn->nat_info->min_addr; - first_addr = ct_addr; - min_port = MIN_NAT_EPHEMERAL_PORT; - max_port = MAX_NAT_EPHEMERAL_PORT; - } else { - break; - } + } + + goto next_addr; + } + + FOR_EACH_PORT_IN_RANGE(curr_dport, min_dport, max_dport) { + nat_conn->rev_key.src.port = htons(curr_dport); + FOR_EACH_PORT_IN_RANGE(curr_sport, min_sport, max_sport) { + nat_conn->rev_key.dst.port = htons(curr_sport); + if (!conn_lookup(ct, &nat_conn->rev_key, + time_msec(), NULL, NULL)) { + return true; } - first_port = min_port; - port = first_port; - all_ports_tried = false; } } - return false; + + /* Check if next IP is in range and respin. Otherwise, notify + * exhaustion to the caller. */ +next_addr: + if (next_addr_in_range_guarded(&curr_addr, &min_addr, + &max_addr, &guard_addr, + conn->key.dl_type == htons(ETH_TYPE_IP))) { + return false; + } + + goto another_round; } static enum ct_update_res diff --git a/lib/ovs-actions.xml b/lib/ovs-actions.xml index f285350eb..c94b5f3b3 100644 --- a/lib/ovs-actions.xml +++ b/lib/ovs-actions.xml @@ -2138,8 +2138,7 @@ for <var>i</var> in [1,<var>n_members</var>]: <code>nat(src=0.0.0.0)</code>. In this case, when a source port collision is detected during the commit, the source port will be translated to an ephemeral port. If there is no collision, no SNAT - is performed. Note that this is currently only implemented in the - Linux kernel datapath. + is performed. </p> <p> diff --git a/tests/system-userspace-macros.at b/tests/system-userspace-macros.at index 9f0d38dfb..f639ba53a 100644 --- a/tests/system-userspace-macros.at +++ b/tests/system-userspace-macros.at @@ -99,12 +99,10 @@ m4_define([CHECK_CONNTRACK_NAT]) # CHECK_CONNTRACK_ZEROIP_SNAT() # # Perform requirements checks for running conntrack all-zero IP SNAT tests. -# The userspace datapath does not support all-zero IP SNAT. +# The userspace datapath always supports all-zero IP SNAT, so no check is +# needed. # -m4_define([CHECK_CONNTRACK_ZEROIP_SNAT], -[ - AT_SKIP_IF([:]) -]) +m4_define([CHECK_CONNTRACK_ZEROIP_SNAT]) # CHECK_CONNTRACK_TIMEOUT() # |