| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/netfilter.h> |
| #include <linux/rhashtable.h> |
| #include <linux/netdevice.h> |
| #include <net/ip.h> |
| #include <net/ip6_route.h> |
| #include <net/netfilter/nf_tables.h> |
| #include <net/netfilter/nf_flow_table.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| #include <net/netfilter/nf_conntrack_tuple.h> |
| |
| struct flow_offload_entry { |
| struct flow_offload flow; |
| struct nf_conn *ct; |
| struct rcu_head rcu_head; |
| }; |
| |
| static DEFINE_MUTEX(flowtable_lock); |
| static LIST_HEAD(flowtables); |
| |
| static void |
| flow_offload_fill_dir(struct flow_offload *flow, struct nf_conn *ct, |
| struct nf_flow_route *route, |
| enum flow_offload_tuple_dir dir) |
| { |
| struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple; |
| struct nf_conntrack_tuple *ctt = &ct->tuplehash[dir].tuple; |
| struct dst_entry *other_dst = route->tuple[!dir].dst; |
| struct dst_entry *dst = route->tuple[dir].dst; |
| |
| ft->dir = dir; |
| |
| switch (ctt->src.l3num) { |
| case NFPROTO_IPV4: |
| ft->src_v4 = ctt->src.u3.in; |
| ft->dst_v4 = ctt->dst.u3.in; |
| ft->mtu = ip_dst_mtu_maybe_forward(dst, true); |
| break; |
| case NFPROTO_IPV6: |
| ft->src_v6 = ctt->src.u3.in6; |
| ft->dst_v6 = ctt->dst.u3.in6; |
| ft->mtu = ip6_dst_mtu_forward(dst); |
| break; |
| } |
| |
| ft->l3proto = ctt->src.l3num; |
| ft->l4proto = ctt->dst.protonum; |
| ft->src_port = ctt->src.u.tcp.port; |
| ft->dst_port = ctt->dst.u.tcp.port; |
| |
| ft->iifidx = other_dst->dev->ifindex; |
| ft->oifidx = dst->dev->ifindex; |
| ft->dst_cache = dst; |
| } |
| |
| struct flow_offload * |
| flow_offload_alloc(struct nf_conn *ct, struct nf_flow_route *route) |
| { |
| struct flow_offload_entry *entry; |
| struct flow_offload *flow; |
| |
| if (unlikely(nf_ct_is_dying(ct) || |
| !atomic_inc_not_zero(&ct->ct_general.use))) |
| return NULL; |
| |
| entry = kzalloc(sizeof(*entry), GFP_ATOMIC); |
| if (!entry) |
| goto err_ct_refcnt; |
| |
| flow = &entry->flow; |
| |
| if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst)) |
| goto err_dst_cache_original; |
| |
| if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst)) |
| goto err_dst_cache_reply; |
| |
| entry->ct = ct; |
| |
| flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_ORIGINAL); |
| flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_REPLY); |
| |
| if (ct->status & IPS_SRC_NAT) |
| flow->flags |= FLOW_OFFLOAD_SNAT; |
| if (ct->status & IPS_DST_NAT) |
| flow->flags |= FLOW_OFFLOAD_DNAT; |
| |
| return flow; |
| |
| err_dst_cache_reply: |
| dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst); |
| err_dst_cache_original: |
| kfree(entry); |
| err_ct_refcnt: |
| nf_ct_put(ct); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(flow_offload_alloc); |
| |
| static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp) |
| { |
| tcp->state = TCP_CONNTRACK_ESTABLISHED; |
| tcp->seen[0].td_maxwin = 0; |
| tcp->seen[1].td_maxwin = 0; |
| } |
| |
| #define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT (120 * HZ) |
| #define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT (30 * HZ) |
| |
| static void flow_offload_fixup_ct_state(struct nf_conn *ct) |
| { |
| const struct nf_conntrack_l4proto *l4proto; |
| unsigned int timeout; |
| int l4num; |
| |
| l4num = nf_ct_protonum(ct); |
| if (l4num == IPPROTO_TCP) |
| flow_offload_fixup_tcp(&ct->proto.tcp); |
| |
| l4proto = nf_ct_l4proto_find(l4num); |
| if (!l4proto) |
| return; |
| |
| if (l4num == IPPROTO_TCP) |
| timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT; |
| else if (l4num == IPPROTO_UDP) |
| timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT; |
| else |
| return; |
| |
| ct->timeout = nfct_time_stamp + timeout; |
| } |
| |
| void flow_offload_free(struct flow_offload *flow) |
| { |
| struct flow_offload_entry *e; |
| |
| dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache); |
| dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache); |
| e = container_of(flow, struct flow_offload_entry, flow); |
| if (flow->flags & FLOW_OFFLOAD_DYING) |
| nf_ct_delete(e->ct, 0, 0); |
| nf_ct_put(e->ct); |
| kfree_rcu(e, rcu_head); |
| } |
| EXPORT_SYMBOL_GPL(flow_offload_free); |
| |
| static u32 flow_offload_hash(const void *data, u32 len, u32 seed) |
| { |
| const struct flow_offload_tuple *tuple = data; |
| |
| return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed); |
| } |
| |
| static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed) |
| { |
| const struct flow_offload_tuple_rhash *tuplehash = data; |
| |
| return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed); |
| } |
| |
| static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg, |
| const void *ptr) |
| { |
| const struct flow_offload_tuple *tuple = arg->key; |
| const struct flow_offload_tuple_rhash *x = ptr; |
| |
| if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir))) |
| return 1; |
| |
| return 0; |
| } |
| |
| static const struct rhashtable_params nf_flow_offload_rhash_params = { |
| .head_offset = offsetof(struct flow_offload_tuple_rhash, node), |
| .hashfn = flow_offload_hash, |
| .obj_hashfn = flow_offload_hash_obj, |
| .obj_cmpfn = flow_offload_hash_cmp, |
| .automatic_shrinking = true, |
| }; |
| |
| int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow) |
| { |
| flow->timeout = (u32)jiffies; |
| |
| rhashtable_insert_fast(&flow_table->rhashtable, |
| &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node, |
| nf_flow_offload_rhash_params); |
| rhashtable_insert_fast(&flow_table->rhashtable, |
| &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node, |
| nf_flow_offload_rhash_params); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(flow_offload_add); |
| |
| static void flow_offload_del(struct nf_flowtable *flow_table, |
| struct flow_offload *flow) |
| { |
| struct flow_offload_entry *e; |
| |
| rhashtable_remove_fast(&flow_table->rhashtable, |
| &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node, |
| nf_flow_offload_rhash_params); |
| rhashtable_remove_fast(&flow_table->rhashtable, |
| &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node, |
| nf_flow_offload_rhash_params); |
| |
| e = container_of(flow, struct flow_offload_entry, flow); |
| clear_bit(IPS_OFFLOAD_BIT, &e->ct->status); |
| |
| flow_offload_free(flow); |
| } |
| |
| void flow_offload_teardown(struct flow_offload *flow) |
| { |
| struct flow_offload_entry *e; |
| |
| flow->flags |= FLOW_OFFLOAD_TEARDOWN; |
| |
| e = container_of(flow, struct flow_offload_entry, flow); |
| flow_offload_fixup_ct_state(e->ct); |
| } |
| EXPORT_SYMBOL_GPL(flow_offload_teardown); |
| |
| struct flow_offload_tuple_rhash * |
| flow_offload_lookup(struct nf_flowtable *flow_table, |
| struct flow_offload_tuple *tuple) |
| { |
| struct flow_offload_tuple_rhash *tuplehash; |
| struct flow_offload *flow; |
| int dir; |
| |
| tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple, |
| nf_flow_offload_rhash_params); |
| if (!tuplehash) |
| return NULL; |
| |
| dir = tuplehash->tuple.dir; |
| flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); |
| if (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN)) |
| return NULL; |
| |
| return tuplehash; |
| } |
| EXPORT_SYMBOL_GPL(flow_offload_lookup); |
| |
| static int |
| nf_flow_table_iterate(struct nf_flowtable *flow_table, |
| void (*iter)(struct flow_offload *flow, void *data), |
| void *data) |
| { |
| struct flow_offload_tuple_rhash *tuplehash; |
| struct rhashtable_iter hti; |
| struct flow_offload *flow; |
| int err = 0; |
| |
| rhashtable_walk_enter(&flow_table->rhashtable, &hti); |
| rhashtable_walk_start(&hti); |
| |
| while ((tuplehash = rhashtable_walk_next(&hti))) { |
| if (IS_ERR(tuplehash)) { |
| if (PTR_ERR(tuplehash) != -EAGAIN) { |
| err = PTR_ERR(tuplehash); |
| break; |
| } |
| continue; |
| } |
| if (tuplehash->tuple.dir) |
| continue; |
| |
| flow = container_of(tuplehash, struct flow_offload, tuplehash[0]); |
| |
| iter(flow, data); |
| } |
| rhashtable_walk_stop(&hti); |
| rhashtable_walk_exit(&hti); |
| |
| return err; |
| } |
| |
| static inline bool nf_flow_has_expired(const struct flow_offload *flow) |
| { |
| return (__s32)(flow->timeout - (u32)jiffies) <= 0; |
| } |
| |
| static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data) |
| { |
| struct nf_flowtable *flow_table = data; |
| |
| if (nf_flow_has_expired(flow) || |
| (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN))) |
| flow_offload_del(flow_table, flow); |
| } |
| |
| static void nf_flow_offload_work_gc(struct work_struct *work) |
| { |
| struct nf_flowtable *flow_table; |
| |
| flow_table = container_of(work, struct nf_flowtable, gc_work.work); |
| nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table); |
| queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ); |
| } |
| |
| static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff, |
| __be16 port, __be16 new_port) |
| { |
| struct tcphdr *tcph; |
| |
| if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) || |
| skb_try_make_writable(skb, thoff + sizeof(*tcph))) |
| return -1; |
| |
| tcph = (void *)(skb_network_header(skb) + thoff); |
| inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true); |
| |
| return 0; |
| } |
| |
| static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff, |
| __be16 port, __be16 new_port) |
| { |
| struct udphdr *udph; |
| |
| if (!pskb_may_pull(skb, thoff + sizeof(*udph)) || |
| skb_try_make_writable(skb, thoff + sizeof(*udph))) |
| return -1; |
| |
| udph = (void *)(skb_network_header(skb) + thoff); |
| if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { |
| inet_proto_csum_replace2(&udph->check, skb, port, |
| new_port, true); |
| if (!udph->check) |
| udph->check = CSUM_MANGLED_0; |
| } |
| |
| return 0; |
| } |
| |
| static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff, |
| u8 protocol, __be16 port, __be16 new_port) |
| { |
| switch (protocol) { |
| case IPPROTO_TCP: |
| if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0) |
| return NF_DROP; |
| break; |
| case IPPROTO_UDP: |
| if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0) |
| return NF_DROP; |
| break; |
| } |
| |
| return 0; |
| } |
| |
| int nf_flow_snat_port(const struct flow_offload *flow, |
| struct sk_buff *skb, unsigned int thoff, |
| u8 protocol, enum flow_offload_tuple_dir dir) |
| { |
| struct flow_ports *hdr; |
| __be16 port, new_port; |
| |
| if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) || |
| skb_try_make_writable(skb, thoff + sizeof(*hdr))) |
| return -1; |
| |
| hdr = (void *)(skb_network_header(skb) + thoff); |
| |
| switch (dir) { |
| case FLOW_OFFLOAD_DIR_ORIGINAL: |
| port = hdr->source; |
| new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port; |
| hdr->source = new_port; |
| break; |
| case FLOW_OFFLOAD_DIR_REPLY: |
| port = hdr->dest; |
| new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port; |
| hdr->dest = new_port; |
| break; |
| default: |
| return -1; |
| } |
| |
| return nf_flow_nat_port(skb, thoff, protocol, port, new_port); |
| } |
| EXPORT_SYMBOL_GPL(nf_flow_snat_port); |
| |
| int nf_flow_dnat_port(const struct flow_offload *flow, |
| struct sk_buff *skb, unsigned int thoff, |
| u8 protocol, enum flow_offload_tuple_dir dir) |
| { |
| struct flow_ports *hdr; |
| __be16 port, new_port; |
| |
| if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) || |
| skb_try_make_writable(skb, thoff + sizeof(*hdr))) |
| return -1; |
| |
| hdr = (void *)(skb_network_header(skb) + thoff); |
| |
| switch (dir) { |
| case FLOW_OFFLOAD_DIR_ORIGINAL: |
| port = hdr->dest; |
| new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port; |
| hdr->dest = new_port; |
| break; |
| case FLOW_OFFLOAD_DIR_REPLY: |
| port = hdr->source; |
| new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port; |
| hdr->source = new_port; |
| break; |
| default: |
| return -1; |
| } |
| |
| return nf_flow_nat_port(skb, thoff, protocol, port, new_port); |
| } |
| EXPORT_SYMBOL_GPL(nf_flow_dnat_port); |
| |
| int nf_flow_table_init(struct nf_flowtable *flowtable) |
| { |
| int err; |
| |
| INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc); |
| |
| err = rhashtable_init(&flowtable->rhashtable, |
| &nf_flow_offload_rhash_params); |
| if (err < 0) |
| return err; |
| |
| queue_delayed_work(system_power_efficient_wq, |
| &flowtable->gc_work, HZ); |
| |
| mutex_lock(&flowtable_lock); |
| list_add(&flowtable->list, &flowtables); |
| mutex_unlock(&flowtable_lock); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(nf_flow_table_init); |
| |
| static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data) |
| { |
| struct net_device *dev = data; |
| struct flow_offload_entry *e; |
| |
| e = container_of(flow, struct flow_offload_entry, flow); |
| |
| if (!dev) { |
| flow_offload_teardown(flow); |
| return; |
| } |
| if (net_eq(nf_ct_net(e->ct), dev_net(dev)) && |
| (flow->tuplehash[0].tuple.iifidx == dev->ifindex || |
| flow->tuplehash[1].tuple.iifidx == dev->ifindex)) |
| flow_offload_dead(flow); |
| } |
| |
| static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable, |
| struct net_device *dev) |
| { |
| nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev); |
| flush_delayed_work(&flowtable->gc_work); |
| } |
| |
| void nf_flow_table_cleanup(struct net_device *dev) |
| { |
| struct nf_flowtable *flowtable; |
| |
| mutex_lock(&flowtable_lock); |
| list_for_each_entry(flowtable, &flowtables, list) |
| nf_flow_table_iterate_cleanup(flowtable, dev); |
| mutex_unlock(&flowtable_lock); |
| } |
| EXPORT_SYMBOL_GPL(nf_flow_table_cleanup); |
| |
| void nf_flow_table_free(struct nf_flowtable *flow_table) |
| { |
| mutex_lock(&flowtable_lock); |
| list_del(&flow_table->list); |
| mutex_unlock(&flowtable_lock); |
| cancel_delayed_work_sync(&flow_table->gc_work); |
| nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL); |
| nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table); |
| rhashtable_destroy(&flow_table->rhashtable); |
| } |
| EXPORT_SYMBOL_GPL(nf_flow_table_free); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); |