| /* 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 <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> |
| |
| LIST_HEAD(nf_conntrack_expect_list); |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_list); |
| |
| kmem_cache_t *nf_conntrack_expect_cachep __read_mostly; |
| static unsigned int nf_conntrack_expect_next_id; |
| |
| /* 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); |
| |
| NF_CT_ASSERT(master_help); |
| NF_CT_ASSERT(!timer_pending(&exp->timeout)); |
| |
| list_del(&exp->list); |
| NF_CT_STAT_INC(expect_delete); |
| master_help->expecting--; |
| nf_conntrack_expect_put(exp); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_unlink_expect); |
| |
| static void expectation_timed_out(unsigned long ul_expect) |
| { |
| struct nf_conntrack_expect *exp = (void *)ul_expect; |
| |
| write_lock_bh(&nf_conntrack_lock); |
| nf_ct_unlink_expect(exp); |
| write_unlock_bh(&nf_conntrack_lock); |
| nf_conntrack_expect_put(exp); |
| } |
| |
| struct nf_conntrack_expect * |
| __nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *i; |
| |
| list_for_each_entry(i, &nf_conntrack_expect_list, list) { |
| if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)) |
| return i; |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(__nf_conntrack_expect_find); |
| |
| /* Just find a expectation corresponding to a tuple. */ |
| struct nf_conntrack_expect * |
| nf_conntrack_expect_find_get(const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *i; |
| |
| read_lock_bh(&nf_conntrack_lock); |
| i = __nf_conntrack_expect_find(tuple); |
| if (i) |
| atomic_inc(&i->use); |
| read_unlock_bh(&nf_conntrack_lock); |
| |
| return i; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_find_get); |
| |
| /* If an expectation for this connection is found, it gets delete from |
| * global list then returned. */ |
| struct nf_conntrack_expect * |
| find_expectation(const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_expect *exp; |
| |
| exp = __nf_conntrack_expect_find(tuple); |
| 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_conntrack_expect *i, *tmp; |
| struct nf_conn_help *help = nfct_help(ct); |
| |
| /* Optimization: most connection never expect any others. */ |
| if (!help || help->expecting == 0) |
| return; |
| |
| list_for_each_entry_safe(i, tmp, &nf_conntrack_expect_list, list) { |
| if (i->master == ct && del_timer(&i->timeout)) { |
| nf_ct_unlink_expect(i); |
| nf_conntrack_expect_put(i); |
| } |
| } |
| } |
| 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 intersect_mask; |
| int count; |
| |
| intersect_mask.src.l3num = a->mask.src.l3num & b->mask.src.l3num; |
| intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all; |
| intersect_mask.dst.u.all = a->mask.dst.u.all & b->mask.dst.u.all; |
| intersect_mask.dst.protonum = a->mask.dst.protonum |
| & b->mask.dst.protonum; |
| |
| 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]; |
| } |
| |
| for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){ |
| intersect_mask.dst.u3.all[count] = |
| a->mask.dst.u3.all[count] & b->mask.dst.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 |
| && nf_ct_tuple_equal(&a->tuple, &b->tuple) |
| && nf_ct_tuple_equal(&a->mask, &b->mask); |
| } |
| |
| /* Generally a bad idea to call this: could have matched already. */ |
| void nf_conntrack_unexpect_related(struct nf_conntrack_expect *exp) |
| { |
| struct nf_conntrack_expect *i; |
| |
| write_lock_bh(&nf_conntrack_lock); |
| /* choose the the oldest expectation to evict */ |
| list_for_each_entry_reverse(i, &nf_conntrack_expect_list, list) { |
| if (expect_matches(i, exp) && del_timer(&i->timeout)) { |
| nf_ct_unlink_expect(i); |
| write_unlock_bh(&nf_conntrack_lock); |
| nf_conntrack_expect_put(i); |
| return; |
| } |
| } |
| write_unlock_bh(&nf_conntrack_lock); |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_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_conntrack_expect_alloc(struct nf_conn *me) |
| { |
| struct nf_conntrack_expect *new; |
| |
| new = kmem_cache_alloc(nf_conntrack_expect_cachep, GFP_ATOMIC); |
| if (!new) |
| return NULL; |
| |
| new->master = me; |
| atomic_set(&new->use, 1); |
| return new; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_alloc); |
| |
| void nf_conntrack_expect_init(struct nf_conntrack_expect *exp, int family, |
| union nf_conntrack_address *saddr, |
| union nf_conntrack_address *daddr, |
| u_int8_t proto, __be16 *src, __be16 *dst) |
| { |
| int len; |
| |
| if (family == AF_INET) |
| len = 4; |
| else |
| len = 16; |
| |
| exp->flags = 0; |
| exp->expectfn = NULL; |
| exp->helper = NULL; |
| exp->tuple.src.l3num = family; |
| exp->tuple.dst.protonum = proto; |
| exp->mask.src.l3num = 0xFFFF; |
| exp->mask.dst.protonum = 0xFF; |
| |
| 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 (daddr) { |
| 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); |
| memset(&exp->mask.dst.u3, 0xFF, len); |
| if (sizeof(exp->mask.dst.u3) > len) |
| memset((void *)&exp->mask.dst.u3 + len, 0x00, |
| sizeof(exp->mask.dst.u3) - len); |
| } else { |
| memset(&exp->tuple.dst.u3, 0x00, sizeof(exp->tuple.dst.u3)); |
| memset(&exp->mask.dst.u3, 0x00, sizeof(exp->mask.dst.u3)); |
| } |
| |
| if (src) { |
| exp->tuple.src.u.all = (__force u16)*src; |
| exp->mask.src.u.all = 0xFFFF; |
| } else { |
| exp->tuple.src.u.all = 0; |
| exp->mask.src.u.all = 0; |
| } |
| |
| if (dst) { |
| exp->tuple.dst.u.all = (__force u16)*dst; |
| exp->mask.dst.u.all = 0xFFFF; |
| } else { |
| exp->tuple.dst.u.all = 0; |
| exp->mask.dst.u.all = 0; |
| } |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_init); |
| |
| void nf_conntrack_expect_put(struct nf_conntrack_expect *exp) |
| { |
| if (atomic_dec_and_test(&exp->use)) |
| kmem_cache_free(nf_conntrack_expect_cachep, exp); |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_put); |
| |
| static void nf_conntrack_expect_insert(struct nf_conntrack_expect *exp) |
| { |
| struct nf_conn_help *master_help = nfct_help(exp->master); |
| |
| atomic_inc(&exp->use); |
| master_help->expecting++; |
| list_add(&exp->list, &nf_conntrack_expect_list); |
| |
| init_timer(&exp->timeout); |
| exp->timeout.data = (unsigned long)exp; |
| exp->timeout.function = expectation_timed_out; |
| exp->timeout.expires = jiffies + master_help->helper->timeout * HZ; |
| add_timer(&exp->timeout); |
| |
| exp->id = ++nf_conntrack_expect_next_id; |
| atomic_inc(&exp->use); |
| NF_CT_STAT_INC(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 *i; |
| |
| list_for_each_entry_reverse(i, &nf_conntrack_expect_list, list) { |
| if (i->master == master) { |
| if (del_timer(&i->timeout)) { |
| nf_ct_unlink_expect(i); |
| nf_conntrack_expect_put(i); |
| } |
| break; |
| } |
| } |
| } |
| |
| static inline int refresh_timer(struct nf_conntrack_expect *i) |
| { |
| struct nf_conn_help *master_help = nfct_help(i->master); |
| |
| if (!del_timer(&i->timeout)) |
| return 0; |
| |
| i->timeout.expires = jiffies + master_help->helper->timeout*HZ; |
| add_timer(&i->timeout); |
| return 1; |
| } |
| |
| int nf_conntrack_expect_related(struct nf_conntrack_expect *expect) |
| { |
| struct nf_conntrack_expect *i; |
| struct nf_conn *master = expect->master; |
| struct nf_conn_help *master_help = nfct_help(master); |
| int ret; |
| |
| NF_CT_ASSERT(master_help); |
| |
| write_lock_bh(&nf_conntrack_lock); |
| list_for_each_entry(i, &nf_conntrack_expect_list, list) { |
| 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? */ |
| if (master_help->helper->max_expected && |
| master_help->expecting >= master_help->helper->max_expected) |
| evict_oldest_expect(master); |
| |
| nf_conntrack_expect_insert(expect); |
| nf_conntrack_expect_event(IPEXP_NEW, expect); |
| ret = 0; |
| out: |
| write_unlock_bh(&nf_conntrack_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_expect_related); |
| |
| #ifdef CONFIG_PROC_FS |
| static void *exp_seq_start(struct seq_file *s, loff_t *pos) |
| { |
| struct list_head *e = &nf_conntrack_expect_list; |
| loff_t i; |
| |
| /* strange seq_file api calls stop even if we fail, |
| * thus we need to grab lock since stop unlocks */ |
| read_lock_bh(&nf_conntrack_lock); |
| |
| if (list_empty(e)) |
| return NULL; |
| |
| for (i = 0; i <= *pos; i++) { |
| e = e->next; |
| if (e == &nf_conntrack_expect_list) |
| return NULL; |
| } |
| return e; |
| } |
| |
| static void *exp_seq_next(struct seq_file *s, void *v, loff_t *pos) |
| { |
| struct list_head *e = v; |
| |
| ++*pos; |
| e = e->next; |
| |
| if (e == &nf_conntrack_expect_list) |
| return NULL; |
| |
| return e; |
| } |
| |
| static void exp_seq_stop(struct seq_file *s, void *v) |
| { |
| read_unlock_bh(&nf_conntrack_lock); |
| } |
| |
| static int exp_seq_show(struct seq_file *s, void *v) |
| { |
| struct nf_conntrack_expect *expect = v; |
| |
| 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)); |
| return seq_putc(s, '\n'); |
| } |
| |
| static 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(file, &exp_seq_ops); |
| } |
| |
| struct file_operations exp_file_ops = { |
| .owner = THIS_MODULE, |
| .open = exp_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release |
| }; |
| #endif /* CONFIG_PROC_FS */ |