diff options
Diffstat (limited to 'net/netfilter/nf_flow_table_core.c')
| -rw-r--r-- | net/netfilter/nf_flow_table_core.c | 526 |
1 files changed, 526 insertions, 0 deletions
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c new file mode 100644 index 0000000000000..eb0d1658ac055 --- /dev/null +++ b/net/netfilter/nf_flow_table_core.c @@ -0,0 +1,526 @@ +#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 *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 = route->tuple[dir].ifindex; + ft->oifidx = route->tuple[!dir].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; +} + +static void flow_offload_fixup_ct_state(struct nf_conn *ct) +{ + const struct nf_conntrack_l4proto *l4proto; + struct net *net = nf_ct_net(ct); + unsigned int *timeouts; + 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(nf_ct_l3num(ct), l4num); + if (!l4proto) + return; + + timeouts = l4proto->get_timeouts(net); + if (!timeouts) + return; + + if (l4num == IPPROTO_TCP) + timeout = timeouts[TCP_CONNTRACK_ESTABLISHED]; + else if (l4num == IPPROTO_UDP) + timeout = timeouts[UDP_CT_REPLIED]; + 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_fast(&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); + +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; + + err = rhashtable_walk_init(&flow_table->rhashtable, &hti, GFP_KERNEL); + if (err) + return err; + + rhashtable_walk_start(&hti); + + while ((tuplehash = rhashtable_walk_next(&hti))) { + if (IS_ERR(tuplehash)) { + err = PTR_ERR(tuplehash); + if (err != -EAGAIN) + goto out; + + continue; + } + if (tuplehash->tuple.dir) + continue; + + flow = container_of(tuplehash, struct flow_offload, tuplehash[0]); + + iter(flow, data); + } +out: + rhashtable_walk_stop(&hti); + rhashtable_walk_exit(&hti); + + return err; +} +EXPORT_SYMBOL_GPL(nf_flow_table_iterate); + +static inline bool nf_flow_has_expired(const struct flow_offload *flow) +{ + return (__s32)(flow->timeout - (u32)jiffies) <= 0; +} + +static int nf_flow_offload_gc_step(struct nf_flowtable *flow_table) +{ + struct flow_offload_tuple_rhash *tuplehash; + struct rhashtable_iter hti; + struct flow_offload *flow; + int err; + + err = rhashtable_walk_init(&flow_table->rhashtable, &hti, GFP_KERNEL); + if (err) + return 0; + + rhashtable_walk_start(&hti); + + while ((tuplehash = rhashtable_walk_next(&hti))) { + if (IS_ERR(tuplehash)) { + err = PTR_ERR(tuplehash); + if (err != -EAGAIN) + goto out; + + continue; + } + if (tuplehash->tuple.dir) + continue; + + flow = container_of(tuplehash, struct flow_offload, tuplehash[0]); + + if (nf_flow_has_expired(flow) || + (flow->flags & (FLOW_OFFLOAD_DYING | + FLOW_OFFLOAD_TEARDOWN))) + flow_offload_del(flow_table, flow); + } +out: + rhashtable_walk_stop(&hti); + rhashtable_walk_exit(&hti); + + return 1; +} + +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_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; + + if (!dev) { + flow_offload_teardown(flow); + return; + } + + if (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 *net, 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); + WARN_ON(!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>"); |