diff options
author | Florian Westphal <fw@strlen.de> | 2017-12-09 21:01:08 +0100 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-01-08 18:01:22 +0100 |
commit | 625c556118f3c2fd28bb8ef6da18c53bd4037be4 (patch) | |
tree | e67a0e7ac8ae1e482aa0af0f5363a74a37011228 /net/netfilter/xt_connlimit.c | |
parent | c2f9eafee9aaeedaad9eadbf47913f4681d723df (diff) |
netfilter: connlimit: split xt_connlimit into front and backend
This allows to reuse xt_connlimit infrastructure from nf_tables.
The upcoming nf_tables frontend can just pass in an nftables register
as input key, this allows limiting by any nft-supported key, including
concatenations.
For xt_connlimit, pass in the zone and the ip/ipv6 address.
With help from Yi-Hung Wei.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/xt_connlimit.c')
-rw-r--r-- | net/netfilter/xt_connlimit.c | 369 |
1 files changed, 24 insertions, 345 deletions
diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c index a6214f235333..b1b17b9353e1 100644 --- a/net/netfilter/xt_connlimit.c +++ b/net/netfilter/xt_connlimit.c @@ -12,292 +12,30 @@ * GPL (C) 1999 Rusty Russell (rusty@rustcorp.com.au). */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -#include <linux/in.h> -#include <linux/in6.h> -#include <linux/ip.h> -#include <linux/ipv6.h> -#include <linux/jhash.h> -#include <linux/slab.h> -#include <linux/list.h> -#include <linux/rbtree.h> + #include <linux/module.h> -#include <linux/random.h> #include <linux/skbuff.h> -#include <linux/spinlock.h> -#include <linux/netfilter/nf_conntrack_tcp.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_connlimit.h> + #include <net/netfilter/nf_conntrack.h> #include <net/netfilter/nf_conntrack_core.h> #include <net/netfilter/nf_conntrack_tuple.h> #include <net/netfilter/nf_conntrack_zones.h> - -#define CONNLIMIT_SLOTS 256U - -#ifdef CONFIG_LOCKDEP -#define CONNLIMIT_LOCK_SLOTS 8U -#else -#define CONNLIMIT_LOCK_SLOTS 256U -#endif - -#define CONNLIMIT_GC_MAX_NODES 8 - -/* we will save the tuples of all connections we care about */ -struct xt_connlimit_conn { - struct hlist_node node; - struct nf_conntrack_tuple tuple; -}; - -struct xt_connlimit_rb { - struct rb_node node; - struct hlist_head hhead; /* connections/hosts in same subnet */ - union nf_inet_addr addr; /* search key */ -}; - -static spinlock_t xt_connlimit_locks[CONNLIMIT_LOCK_SLOTS] __cacheline_aligned_in_smp; - -struct xt_connlimit_data { - struct rb_root climit_root[CONNLIMIT_SLOTS]; -}; - -static u_int32_t connlimit_rnd __read_mostly; -static struct kmem_cache *connlimit_rb_cachep __read_mostly; -static struct kmem_cache *connlimit_conn_cachep __read_mostly; - -static inline unsigned int connlimit_iphash(__be32 addr) -{ - return jhash_1word((__force __u32)addr, - connlimit_rnd) % CONNLIMIT_SLOTS; -} - -static inline unsigned int -connlimit_iphash6(const union nf_inet_addr *addr) -{ - return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), - connlimit_rnd) % CONNLIMIT_SLOTS; -} - -static inline bool already_closed(const struct nf_conn *conn) -{ - if (nf_ct_protonum(conn) == IPPROTO_TCP) - return conn->proto.tcp.state == TCP_CONNTRACK_TIME_WAIT || - conn->proto.tcp.state == TCP_CONNTRACK_CLOSE; - else - return 0; -} - -static int -same_source(const union nf_inet_addr *addr, - const union nf_inet_addr *u3, u_int8_t family) -{ - if (family == NFPROTO_IPV4) - return ntohl(addr->ip) - ntohl(u3->ip); - - return memcmp(addr->ip6, u3->ip6, sizeof(addr->ip6)); -} - -static bool add_hlist(struct hlist_head *head, - const struct nf_conntrack_tuple *tuple, - const union nf_inet_addr *addr) -{ - struct xt_connlimit_conn *conn; - - conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); - if (conn == NULL) - return false; - conn->tuple = *tuple; - hlist_add_head(&conn->node, head); - return true; -} - -static unsigned int check_hlist(struct net *net, - struct hlist_head *head, - const struct nf_conntrack_tuple *tuple, - const struct nf_conntrack_zone *zone, - bool *addit) -{ - const struct nf_conntrack_tuple_hash *found; - struct xt_connlimit_conn *conn; - struct hlist_node *n; - struct nf_conn *found_ct; - unsigned int length = 0; - - *addit = true; - - /* check the saved connections */ - hlist_for_each_entry_safe(conn, n, head, node) { - found = nf_conntrack_find_get(net, zone, &conn->tuple); - if (found == NULL) { - hlist_del(&conn->node); - kmem_cache_free(connlimit_conn_cachep, conn); - continue; - } - - found_ct = nf_ct_tuplehash_to_ctrack(found); - - if (nf_ct_tuple_equal(&conn->tuple, tuple)) { - /* - * Just to be sure we have it only once in the list. - * We should not see tuples twice unless someone hooks - * this into a table without "-p tcp --syn". - */ - *addit = false; - } else if (already_closed(found_ct)) { - /* - * we do not care about connections which are - * closed already -> ditch it - */ - nf_ct_put(found_ct); - hlist_del(&conn->node); - kmem_cache_free(connlimit_conn_cachep, conn); - continue; - } - - nf_ct_put(found_ct); - length++; - } - - return length; -} - -static void tree_nodes_free(struct rb_root *root, - struct xt_connlimit_rb *gc_nodes[], - unsigned int gc_count) -{ - struct xt_connlimit_rb *rbconn; - - while (gc_count) { - rbconn = gc_nodes[--gc_count]; - rb_erase(&rbconn->node, root); - kmem_cache_free(connlimit_rb_cachep, rbconn); - } -} - -static unsigned int -count_tree(struct net *net, struct rb_root *root, - const struct nf_conntrack_tuple *tuple, - const union nf_inet_addr *addr, - u8 family, const struct nf_conntrack_zone *zone) -{ - struct xt_connlimit_rb *gc_nodes[CONNLIMIT_GC_MAX_NODES]; - struct rb_node **rbnode, *parent; - struct xt_connlimit_rb *rbconn; - struct xt_connlimit_conn *conn; - unsigned int gc_count; - bool no_gc = false; - - restart: - gc_count = 0; - parent = NULL; - rbnode = &(root->rb_node); - while (*rbnode) { - int diff; - bool addit; - - rbconn = rb_entry(*rbnode, struct xt_connlimit_rb, node); - - parent = *rbnode; - diff = same_source(addr, &rbconn->addr, family); - if (diff < 0) { - rbnode = &((*rbnode)->rb_left); - } else if (diff > 0) { - rbnode = &((*rbnode)->rb_right); - } else { - /* same source network -> be counted! */ - unsigned int count; - count = check_hlist(net, &rbconn->hhead, tuple, zone, &addit); - - tree_nodes_free(root, gc_nodes, gc_count); - if (!addit) - return count; - - if (!add_hlist(&rbconn->hhead, tuple, addr)) - return 0; /* hotdrop */ - - return count + 1; - } - - if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes)) - continue; - - /* only used for GC on hhead, retval and 'addit' ignored */ - check_hlist(net, &rbconn->hhead, tuple, zone, &addit); - if (hlist_empty(&rbconn->hhead)) - gc_nodes[gc_count++] = rbconn; - } - - if (gc_count) { - no_gc = true; - tree_nodes_free(root, gc_nodes, gc_count); - /* tree_node_free before new allocation permits - * allocator to re-use newly free'd object. - * - * This is a rare event; in most cases we will find - * existing node to re-use. (or gc_count is 0). - */ - goto restart; - } - - /* no match, need to insert new node */ - rbconn = kmem_cache_alloc(connlimit_rb_cachep, GFP_ATOMIC); - if (rbconn == NULL) - return 0; - - conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); - if (conn == NULL) { - kmem_cache_free(connlimit_rb_cachep, rbconn); - return 0; - } - - conn->tuple = *tuple; - rbconn->addr = *addr; - - INIT_HLIST_HEAD(&rbconn->hhead); - hlist_add_head(&conn->node, &rbconn->hhead); - - rb_link_node(&rbconn->node, parent, rbnode); - rb_insert_color(&rbconn->node, root); - return 1; -} - -static int count_them(struct net *net, - struct xt_connlimit_data *data, - const struct nf_conntrack_tuple *tuple, - const union nf_inet_addr *addr, - u_int8_t family, - const struct nf_conntrack_zone *zone) -{ - struct rb_root *root; - int count; - u32 hash; - - if (family == NFPROTO_IPV6) - hash = connlimit_iphash6(addr); - else - hash = connlimit_iphash(addr->ip); - root = &data->climit_root[hash]; - - spin_lock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]); - - count = count_tree(net, root, tuple, addr, family, zone); - - spin_unlock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]); - - return count; -} +#include <net/netfilter/nf_conntrack_count.h> static bool connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) { struct net *net = xt_net(par); const struct xt_connlimit_info *info = par->matchinfo; - union nf_inet_addr addr; struct nf_conntrack_tuple tuple; const struct nf_conntrack_tuple *tuple_ptr = &tuple; const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; enum ip_conntrack_info ctinfo; const struct nf_conn *ct; unsigned int connections; + u32 key[5]; ct = nf_ct_get(skb, &ctinfo); if (ct != NULL) { @@ -310,6 +48,7 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) if (xt_family(par) == NFPROTO_IPV6) { const struct ipv6hdr *iph = ipv6_hdr(skb); + union nf_inet_addr addr; unsigned int i; memcpy(&addr.ip6, (info->flags & XT_CONNLIMIT_DADDR) ? @@ -317,22 +56,24 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) for (i = 0; i < ARRAY_SIZE(addr.ip6); ++i) addr.ip6[i] &= info->mask.ip6[i]; + memcpy(key, &addr, sizeof(addr.ip6)); + key[4] = zone->id; } else { const struct iphdr *iph = ip_hdr(skb); - addr.ip = (info->flags & XT_CONNLIMIT_DADDR) ? + key[0] = (info->flags & XT_CONNLIMIT_DADDR) ? iph->daddr : iph->saddr; - addr.ip &= info->mask.ip; + key[0] &= info->mask.ip; + key[1] = zone->id; } - connections = count_them(net, info->data, tuple_ptr, &addr, - xt_family(par), zone); + connections = nf_conncount_count(net, info->data, key, + xt_family(par), tuple_ptr, zone); if (connections == 0) /* kmalloc failed, drop it entirely */ goto hotdrop; - return (connections > info->limit) ^ - !!(info->flags & XT_CONNLIMIT_INVERT); + return (connections > info->limit) ^ !!(info->flags & XT_CONNLIMIT_INVERT); hotdrop: par->hotdrop = true; @@ -342,61 +83,27 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) static int connlimit_mt_check(const struct xt_mtchk_param *par) { struct xt_connlimit_info *info = par->matchinfo; - unsigned int i; - int ret; + unsigned int keylen; - net_get_random_once(&connlimit_rnd, sizeof(connlimit_rnd)); - - ret = nf_ct_netns_get(par->net, par->family); - if (ret < 0) { - pr_info("cannot load conntrack support for " - "address family %u\n", par->family); - return ret; - } + keylen = sizeof(u32); + if (par->family == NFPROTO_IPV6) + keylen += sizeof(struct in6_addr); + else + keylen += sizeof(struct in_addr); /* init private data */ - info->data = kmalloc(sizeof(struct xt_connlimit_data), GFP_KERNEL); - if (info->data == NULL) { - nf_ct_netns_put(par->net, par->family); - return -ENOMEM; - } - - for (i = 0; i < ARRAY_SIZE(info->data->climit_root); ++i) - info->data->climit_root[i] = RB_ROOT; + info->data = nf_conncount_init(par->net, par->family, keylen); + if (IS_ERR(info->data)) + return PTR_ERR(info->data); return 0; } -static void destroy_tree(struct rb_root *r) -{ - struct xt_connlimit_conn *conn; - struct xt_connlimit_rb *rbconn; - struct hlist_node *n; - struct rb_node *node; - - while ((node = rb_first(r)) != NULL) { - rbconn = rb_entry(node, struct xt_connlimit_rb, node); - - rb_erase(node, r); - - hlist_for_each_entry_safe(conn, n, &rbconn->hhead, node) - kmem_cache_free(connlimit_conn_cachep, conn); - - kmem_cache_free(connlimit_rb_cachep, rbconn); - } -} - static void connlimit_mt_destroy(const struct xt_mtdtor_param *par) { const struct xt_connlimit_info *info = par->matchinfo; - unsigned int i; - - nf_ct_netns_put(par->net, par->family); - - for (i = 0; i < ARRAY_SIZE(info->data->climit_root); ++i) - destroy_tree(&info->data->climit_root[i]); - kfree(info->data); + nf_conncount_destroy(par->net, par->family, info->data); } static struct xt_match connlimit_mt_reg __read_mostly = { @@ -413,40 +120,12 @@ static struct xt_match connlimit_mt_reg __read_mostly = { static int __init connlimit_mt_init(void) { - int ret, i; - - BUILD_BUG_ON(CONNLIMIT_LOCK_SLOTS > CONNLIMIT_SLOTS); - BUILD_BUG_ON((CONNLIMIT_SLOTS % CONNLIMIT_LOCK_SLOTS) != 0); - - for (i = 0; i < CONNLIMIT_LOCK_SLOTS; ++i) - spin_lock_init(&xt_connlimit_locks[i]); - - connlimit_conn_cachep = kmem_cache_create("xt_connlimit_conn", - sizeof(struct xt_connlimit_conn), - 0, 0, NULL); - if (!connlimit_conn_cachep) - return -ENOMEM; - - connlimit_rb_cachep = kmem_cache_create("xt_connlimit_rb", - sizeof(struct xt_connlimit_rb), - 0, 0, NULL); - if (!connlimit_rb_cachep) { - kmem_cache_destroy(connlimit_conn_cachep); - return -ENOMEM; - } - ret = xt_register_match(&connlimit_mt_reg); - if (ret != 0) { - kmem_cache_destroy(connlimit_conn_cachep); - kmem_cache_destroy(connlimit_rb_cachep); - } - return ret; + return xt_register_match(&connlimit_mt_reg); } static void __exit connlimit_mt_exit(void) { xt_unregister_match(&connlimit_mt_reg); - kmem_cache_destroy(connlimit_conn_cachep); - kmem_cache_destroy(connlimit_rb_cachep); } module_init(connlimit_mt_init); |