| /* Expectation handling for nf_conntrack. */ |
| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/netfilter.h> |
| #include <linux/skbuff.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/stddef.h> |
| #include <linux/slab.h> |
| #include <linux/err.h> |
| #include <linux/percpu.h> |
| #include <linux/kernel.h> |
| #include <linux/jhash.h> |
| #include <net/net_namespace.h> |
| |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| #include <net/netfilter/nf_conntrack_expect.h> |
| #include <net/netfilter/nf_conntrack_helper.h> |
| #include <net/netfilter/nf_conntrack_tuple.h> |
| |
| unsigned int nf_ct_expect_hsize __read_mostly; |
| EXPORT_SYMBOL_GPL(nf_ct_expect_hsize); |
| |
| static unsigned int nf_ct_expect_hash_rnd __read_mostly; |
| unsigned int nf_ct_expect_max __read_mostly; |
| static int nf_ct_expect_hash_rnd_initted __read_mostly; |
| |
| static struct kmem_cache *nf_ct_expect_cachep __read_mostly; |
| |
| /* nf_conntrack_expect helper functions */ |
| void nf_ct_unlink_expect(struct nf_conntrack_expect *exp) |
| { |
| struct nf_conn_help *master_help = nfct_help(exp->master); |
| struct net *net = nf_ct_exp_net(exp); |
| |
| NF_CT_ASSERT(master_help); |
| NF_CT_ASSERT(!timer_pending(&exp->timeout)); |
| |
| hlist_del_rcu(&exp->hnode); |
| net->ct.expect_count--; |
| |
| hlist_del(&exp->lnode); |
| master_help->expecting[exp->class]--; |
| nf_ct_expect_put(exp); |
| |
| NF_CT_STAT_INC(net, expect_delete); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_unlink_expect); |
| |
| static void nf_ct_expectation_timed_out(unsigned long ul_expect) |
| { |
| struct nf_conntrack_expect *exp = (void *)ul_expect; |
| |
| spin_lock_bh(&nf_conntrack_lock); |
| nf_ct_unlink_expect(exp); |
| spin_unlock_bh(&nf_conntrack_lock); |
| nf_ct_expect_put(exp); |
| } |
| |
| static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple) |
| { |
| unsigned int hash; |
| |
| if (unlikely(!nf_ct_expect_hash_rnd_initted)) { |
| get_random_bytes(&nf_ct_expect_hash_rnd, |
| sizeof(nf_ct_expect_hash_rnd)); |
| nf_ct_expect_hash_rnd_initted = 1; |
| } |
| |
| hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all), |
| (((tuple->dst.protonum ^ tuple->src.l3num) << 16) | |
| (__force __u16)tuple->dst.u.all) ^ nf_ct_expect_hash_rnd); |
| return ((u64)hash * nf_ct_expect_hsize) >> 32; |
| } |
| |
| struct nf_conntrack_expect * |
| __nf_ct_expect_find(struct net *net, const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *i; |
| struct hlist_node *n; |
| unsigned int h; |
| |
| if (!net->ct.expect_count) |
| return NULL; |
| |
| h = nf_ct_expect_dst_hash(tuple); |
| hlist_for_each_entry_rcu(i, n, &net->ct.expect_hash[h], hnode) { |
| if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)) |
| return i; |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(__nf_ct_expect_find); |
| |
| /* Just find a expectation corresponding to a tuple. */ |
| struct nf_conntrack_expect * |
| nf_ct_expect_find_get(struct net *net, const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *i; |
| |
| rcu_read_lock(); |
| i = __nf_ct_expect_find(net, tuple); |
| if (i && !atomic_inc_not_zero(&i->use)) |
| i = NULL; |
| rcu_read_unlock(); |
| |
| return i; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_expect_find_get); |
| |
| /* If an expectation for this connection is found, it gets delete from |
| * global list then returned. */ |
| struct nf_conntrack_expect * |
| nf_ct_find_expectation(struct net *net, const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *i, *exp = NULL; |
| struct hlist_node *n; |
| unsigned int h; |
| |
| if (!net->ct.expect_count) |
| return NULL; |
| |
| h = nf_ct_expect_dst_hash(tuple); |
| hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) { |
| if (!(i->flags & NF_CT_EXPECT_INACTIVE) && |
| nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)) { |
| exp = i; |
| break; |
| } |
| } |
| if (!exp) |
| return NULL; |
| |
| /* If master is not in hash table yet (ie. packet hasn't left |
| this machine yet), how can other end know about expected? |
| Hence these are not the droids you are looking for (if |
| master ct never got confirmed, we'd hold a reference to it |
| and weird things would happen to future packets). */ |
| if (!nf_ct_is_confirmed(exp->master)) |
| return NULL; |
| |
| if (exp->flags & NF_CT_EXPECT_PERMANENT) { |
| atomic_inc(&exp->use); |
| return exp; |
| } else if (del_timer(&exp->timeout)) { |
| nf_ct_unlink_expect(exp); |
| return exp; |
| } |
| |
| return NULL; |
| } |
| |
| /* delete all expectations for this conntrack */ |
| void nf_ct_remove_expectations(struct nf_conn *ct) |
| { |
| struct nf_conn_help *help = nfct_help(ct); |
| struct nf_conntrack_expect *exp; |
| struct hlist_node *n, *next; |
| |
| /* Optimization: most connection never expect any others. */ |
| if (!help) |
| return; |
| |
| hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) { |
| if (del_timer(&exp->timeout)) { |
| nf_ct_unlink_expect(exp); |
| nf_ct_expect_put(exp); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_remove_expectations); |
| |
| /* Would two expected things clash? */ |
| static inline int expect_clash(const struct nf_conntrack_expect *a, |
| const struct nf_conntrack_expect *b) |
| { |
| /* Part covered by intersection of masks must be unequal, |
| otherwise they clash */ |
| struct nf_conntrack_tuple_mask intersect_mask; |
| int count; |
| |
| intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all; |
| |
| for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){ |
| intersect_mask.src.u3.all[count] = |
| a->mask.src.u3.all[count] & b->mask.src.u3.all[count]; |
| } |
| |
| return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask); |
| } |
| |
| static inline int expect_matches(const struct nf_conntrack_expect *a, |
| const struct nf_conntrack_expect *b) |
| { |
| return a->master == b->master && a->class == b->class && |
| nf_ct_tuple_equal(&a->tuple, &b->tuple) && |
| nf_ct_tuple_mask_equal(&a->mask, &b->mask); |
| } |
| |
| /* Generally a bad idea to call this: could have matched already. */ |
| void nf_ct_unexpect_related(struct nf_conntrack_expect *exp) |
| { |
| spin_lock_bh(&nf_conntrack_lock); |
| if (del_timer(&exp->timeout)) { |
| nf_ct_unlink_expect(exp); |
| nf_ct_expect_put(exp); |
| } |
| spin_unlock_bh(&nf_conntrack_lock); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_unexpect_related); |
| |
| /* We don't increase the master conntrack refcount for non-fulfilled |
| * conntracks. During the conntrack destruction, the expectations are |
| * always killed before the conntrack itself */ |
| struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me) |
| { |
| struct nf_conntrack_expect *new; |
| |
| new = kmem_cache_alloc(nf_ct_expect_cachep, GFP_ATOMIC); |
| if (!new) |
| return NULL; |
| |
| new->master = me; |
| atomic_set(&new->use, 1); |
| return new; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_expect_alloc); |
| |
| void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, |
| u_int8_t family, |
| const union nf_inet_addr *saddr, |
| const union nf_inet_addr *daddr, |
| u_int8_t proto, const __be16 *src, const __be16 *dst) |
| { |
| int len; |
| |
| if (family == AF_INET) |
| len = 4; |
| else |
| len = 16; |
| |
| exp->flags = 0; |
| exp->class = class; |
| exp->expectfn = NULL; |
| exp->helper = NULL; |
| exp->tuple.src.l3num = family; |
| exp->tuple.dst.protonum = proto; |
| |
| if (saddr) { |
| memcpy(&exp->tuple.src.u3, saddr, len); |
| if (sizeof(exp->tuple.src.u3) > len) |
| /* address needs to be cleared for nf_ct_tuple_equal */ |
| memset((void *)&exp->tuple.src.u3 + len, 0x00, |
| sizeof(exp->tuple.src.u3) - len); |
| memset(&exp->mask.src.u3, 0xFF, len); |
| if (sizeof(exp->mask.src.u3) > len) |
| memset((void *)&exp->mask.src.u3 + len, 0x00, |
| sizeof(exp->mask.src.u3) - len); |
| } else { |
| memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3)); |
| memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3)); |
| } |
| |
| if (src) { |
| exp->tuple.src.u.all = *src; |
| exp->mask.src.u.all = htons(0xFFFF); |
| } else { |
| exp->tuple.src.u.all = 0; |
| exp->mask.src.u.all = 0; |
| } |
| |
| memcpy(&exp->tuple.dst.u3, daddr, len); |
| if (sizeof(exp->tuple.dst.u3) > len) |
| /* address needs to be cleared for nf_ct_tuple_equal */ |
| memset((void *)&exp->tuple.dst.u3 + len, 0x00, |
| sizeof(exp->tuple.dst.u3) - len); |
| |
| exp->tuple.dst.u.all = *dst; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_expect_init); |
| |
| static void nf_ct_expect_free_rcu(struct rcu_head *head) |
| { |
| struct nf_conntrack_expect *exp; |
| |
| exp = container_of(head, struct nf_conntrack_expect, rcu); |
| kmem_cache_free(nf_ct_expect_cachep, exp); |
| } |
| |
| void nf_ct_expect_put(struct nf_conntrack_expect *exp) |
| { |
| if (atomic_dec_and_test(&exp->use)) |
| call_rcu(&exp->rcu, nf_ct_expect_free_rcu); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_expect_put); |
| |
| static void nf_ct_expect_insert(struct nf_conntrack_expect *exp) |
| { |
| struct nf_conn_help *master_help = nfct_help(exp->master); |
| struct net *net = nf_ct_exp_net(exp); |
| const struct nf_conntrack_expect_policy *p; |
| unsigned int h = nf_ct_expect_dst_hash(&exp->tuple); |
| |
| atomic_inc(&exp->use); |
| |
| hlist_add_head(&exp->lnode, &master_help->expectations); |
| master_help->expecting[exp->class]++; |
| |
| hlist_add_head_rcu(&exp->hnode, &net->ct.expect_hash[h]); |
| net->ct.expect_count++; |
| |
| setup_timer(&exp->timeout, nf_ct_expectation_timed_out, |
| (unsigned long)exp); |
| p = &master_help->helper->expect_policy[exp->class]; |
| exp->timeout.expires = jiffies + p->timeout * HZ; |
| add_timer(&exp->timeout); |
| |
| atomic_inc(&exp->use); |
| NF_CT_STAT_INC(net, expect_create); |
| } |
| |
| /* Race with expectations being used means we could have none to find; OK. */ |
| static void evict_oldest_expect(struct nf_conn *master, |
| struct nf_conntrack_expect *new) |
| { |
| struct nf_conn_help *master_help = nfct_help(master); |
| struct nf_conntrack_expect *exp, *last = NULL; |
| struct hlist_node *n; |
| |
| hlist_for_each_entry(exp, n, &master_help->expectations, lnode) { |
| if (exp->class == new->class) |
| last = exp; |
| } |
| |
| if (last && del_timer(&last->timeout)) { |
| nf_ct_unlink_expect(last); |
| nf_ct_expect_put(last); |
| } |
| } |
| |
| static inline int refresh_timer(struct nf_conntrack_expect *i) |
| { |
| struct nf_conn_help *master_help = nfct_help(i->master); |
| const struct nf_conntrack_expect_policy *p; |
| |
| if (!del_timer(&i->timeout)) |
| return 0; |
| |
| p = &master_help->helper->expect_policy[i->class]; |
| i->timeout.expires = jiffies + p->timeout * HZ; |
| add_timer(&i->timeout); |
| return 1; |
| } |
| |
| static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect) |
| { |
| const struct nf_conntrack_expect_policy *p; |
| struct nf_conntrack_expect *i; |
| struct nf_conn *master = expect->master; |
| struct nf_conn_help *master_help = nfct_help(master); |
| struct net *net = nf_ct_exp_net(expect); |
| struct hlist_node *n; |
| unsigned int h; |
| int ret = 1; |
| |
| if (!master_help->helper) { |
| ret = -ESHUTDOWN; |
| goto out; |
| } |
| h = nf_ct_expect_dst_hash(&expect->tuple); |
| hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) { |
| if (expect_matches(i, expect)) { |
| /* Refresh timer: if it's dying, ignore.. */ |
| if (refresh_timer(i)) { |
| ret = 0; |
| goto out; |
| } |
| } else if (expect_clash(i, expect)) { |
| ret = -EBUSY; |
| goto out; |
| } |
| } |
| /* Will be over limit? */ |
| p = &master_help->helper->expect_policy[expect->class]; |
| if (p->max_expected && |
| master_help->expecting[expect->class] >= p->max_expected) { |
| evict_oldest_expect(master, expect); |
| if (master_help->expecting[expect->class] >= p->max_expected) { |
| ret = -EMFILE; |
| goto out; |
| } |
| } |
| |
| if (net->ct.expect_count >= nf_ct_expect_max) { |
| if (net_ratelimit()) |
| printk(KERN_WARNING |
| "nf_conntrack: expectation table full\n"); |
| ret = -EMFILE; |
| } |
| out: |
| return ret; |
| } |
| |
| int nf_ct_expect_related_report(struct nf_conntrack_expect *expect, |
| u32 pid, int report) |
| { |
| int ret; |
| |
| spin_lock_bh(&nf_conntrack_lock); |
| ret = __nf_ct_expect_check(expect); |
| if (ret <= 0) |
| goto out; |
| |
| ret = 0; |
| nf_ct_expect_insert(expect); |
| spin_unlock_bh(&nf_conntrack_lock); |
| nf_ct_expect_event_report(IPEXP_NEW, expect, pid, report); |
| return ret; |
| out: |
| spin_unlock_bh(&nf_conntrack_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_expect_related_report); |
| |
| #ifdef CONFIG_PROC_FS |
| struct ct_expect_iter_state { |
| struct seq_net_private p; |
| unsigned int bucket; |
| }; |
| |
| static struct hlist_node *ct_expect_get_first(struct seq_file *seq) |
| { |
| struct net *net = seq_file_net(seq); |
| struct ct_expect_iter_state *st = seq->private; |
| struct hlist_node *n; |
| |
| for (st->bucket = 0; st->bucket < nf_ct_expect_hsize; st->bucket++) { |
| n = rcu_dereference(net->ct.expect_hash[st->bucket].first); |
| if (n) |
| return n; |
| } |
| return NULL; |
| } |
| |
| static struct hlist_node *ct_expect_get_next(struct seq_file *seq, |
| struct hlist_node *head) |
| { |
| struct net *net = seq_file_net(seq); |
| struct ct_expect_iter_state *st = seq->private; |
| |
| head = rcu_dereference(head->next); |
| while (head == NULL) { |
| if (++st->bucket >= nf_ct_expect_hsize) |
| return NULL; |
| head = rcu_dereference(net->ct.expect_hash[st->bucket].first); |
| } |
| return head; |
| } |
| |
| static struct hlist_node *ct_expect_get_idx(struct seq_file *seq, loff_t pos) |
| { |
| struct hlist_node *head = ct_expect_get_first(seq); |
| |
| if (head) |
| while (pos && (head = ct_expect_get_next(seq, head))) |
| pos--; |
| return pos ? NULL : head; |
| } |
| |
| static void *exp_seq_start(struct seq_file *seq, loff_t *pos) |
| __acquires(RCU) |
| { |
| rcu_read_lock(); |
| return ct_expect_get_idx(seq, *pos); |
| } |
| |
| static void *exp_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| (*pos)++; |
| return ct_expect_get_next(seq, v); |
| } |
| |
| static void exp_seq_stop(struct seq_file *seq, void *v) |
| __releases(RCU) |
| { |
| rcu_read_unlock(); |
| } |
| |
| static int exp_seq_show(struct seq_file *s, void *v) |
| { |
| struct nf_conntrack_expect *expect; |
| struct nf_conntrack_helper *helper; |
| struct hlist_node *n = v; |
| char *delim = ""; |
| |
| expect = hlist_entry(n, struct nf_conntrack_expect, hnode); |
| |
| if (expect->timeout.function) |
| seq_printf(s, "%ld ", timer_pending(&expect->timeout) |
| ? (long)(expect->timeout.expires - jiffies)/HZ : 0); |
| else |
| seq_printf(s, "- "); |
| seq_printf(s, "l3proto = %u proto=%u ", |
| expect->tuple.src.l3num, |
| expect->tuple.dst.protonum); |
| print_tuple(s, &expect->tuple, |
| __nf_ct_l3proto_find(expect->tuple.src.l3num), |
| __nf_ct_l4proto_find(expect->tuple.src.l3num, |
| expect->tuple.dst.protonum)); |
| |
| if (expect->flags & NF_CT_EXPECT_PERMANENT) { |
| seq_printf(s, "PERMANENT"); |
| delim = ","; |
| } |
| if (expect->flags & NF_CT_EXPECT_INACTIVE) |
| seq_printf(s, "%sINACTIVE", delim); |
| |
| helper = rcu_dereference(nfct_help(expect->master)->helper); |
| if (helper) { |
| seq_printf(s, "%s%s", expect->flags ? " " : "", helper->name); |
| if (helper->expect_policy[expect->class].name) |
| seq_printf(s, "/%s", |
| helper->expect_policy[expect->class].name); |
| } |
| |
| return seq_putc(s, '\n'); |
| } |
| |
| static const struct seq_operations exp_seq_ops = { |
| .start = exp_seq_start, |
| .next = exp_seq_next, |
| .stop = exp_seq_stop, |
| .show = exp_seq_show |
| }; |
| |
| static int exp_open(struct inode *inode, struct file *file) |
| { |
| return seq_open_net(inode, file, &exp_seq_ops, |
| sizeof(struct ct_expect_iter_state)); |
| } |
| |
| static const struct file_operations exp_file_ops = { |
| .owner = THIS_MODULE, |
| .open = exp_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release_net, |
| }; |
| #endif /* CONFIG_PROC_FS */ |
| |
| static int exp_proc_init(struct net *net) |
| { |
| #ifdef CONFIG_PROC_FS |
| struct proc_dir_entry *proc; |
| |
| proc = proc_net_fops_create(net, "nf_conntrack_expect", 0440, &exp_file_ops); |
| if (!proc) |
| return -ENOMEM; |
| #endif /* CONFIG_PROC_FS */ |
| return 0; |
| } |
| |
| static void exp_proc_remove(struct net *net) |
| { |
| #ifdef CONFIG_PROC_FS |
| proc_net_remove(net, "nf_conntrack_expect"); |
| #endif /* CONFIG_PROC_FS */ |
| } |
| |
| module_param_named(expect_hashsize, nf_ct_expect_hsize, uint, 0400); |
| |
| int nf_conntrack_expect_init(struct net *net) |
| { |
| int err = -ENOMEM; |
| |
| if (net_eq(net, &init_net)) { |
| if (!nf_ct_expect_hsize) { |
| nf_ct_expect_hsize = net->ct.htable_size / 256; |
| if (!nf_ct_expect_hsize) |
| nf_ct_expect_hsize = 1; |
| } |
| nf_ct_expect_max = nf_ct_expect_hsize * 4; |
| } |
| |
| net->ct.expect_count = 0; |
| net->ct.expect_hash = nf_ct_alloc_hashtable(&nf_ct_expect_hsize, |
| &net->ct.expect_vmalloc, 0); |
| if (net->ct.expect_hash == NULL) |
| goto err1; |
| |
| if (net_eq(net, &init_net)) { |
| nf_ct_expect_cachep = kmem_cache_create("nf_conntrack_expect", |
| sizeof(struct nf_conntrack_expect), |
| 0, 0, NULL); |
| if (!nf_ct_expect_cachep) |
| goto err2; |
| } |
| |
| err = exp_proc_init(net); |
| if (err < 0) |
| goto err3; |
| |
| return 0; |
| |
| err3: |
| if (net_eq(net, &init_net)) |
| kmem_cache_destroy(nf_ct_expect_cachep); |
| err2: |
| nf_ct_free_hashtable(net->ct.expect_hash, net->ct.expect_vmalloc, |
| nf_ct_expect_hsize); |
| err1: |
| return err; |
| } |
| |
| void nf_conntrack_expect_fini(struct net *net) |
| { |
| exp_proc_remove(net); |
| if (net_eq(net, &init_net)) { |
| rcu_barrier(); /* Wait for call_rcu() before destroy */ |
| kmem_cache_destroy(nf_ct_expect_cachep); |
| } |
| nf_ct_free_hashtable(net->ct.expect_hash, net->ct.expect_vmalloc, |
| nf_ct_expect_hsize); |
| } |