Patrick McHardy | 62b7743 | 2006-05-29 18:20:32 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * netfilter module to enforce network quotas |
| 3 | * |
| 4 | * Sam Johnston <samj@samj.net> |
| 5 | */ |
| 6 | #include <linux/skbuff.h> |
| 7 | #include <linux/spinlock.h> |
| 8 | |
| 9 | #include <linux/netfilter/x_tables.h> |
| 10 | #include <linux/netfilter/xt_quota.h> |
| 11 | |
| 12 | MODULE_LICENSE("GPL"); |
| 13 | MODULE_AUTHOR("Sam Johnston <samj@samj.net>"); |
| 14 | |
| 15 | static DEFINE_SPINLOCK(quota_lock); |
| 16 | |
| 17 | static int |
| 18 | match(const struct sk_buff *skb, |
| 19 | const struct net_device *in, const struct net_device *out, |
| 20 | const struct xt_match *match, const void *matchinfo, |
| 21 | int offset, unsigned int protoff, int *hotdrop) |
| 22 | { |
| 23 | struct xt_quota_info *q = ((struct xt_quota_info *)matchinfo)->master; |
| 24 | int ret = q->flags & XT_QUOTA_INVERT ? 1 : 0; |
| 25 | |
| 26 | spin_lock_bh("a_lock); |
| 27 | if (q->quota >= skb->len) { |
| 28 | q->quota -= skb->len; |
| 29 | ret ^= 1; |
| 30 | } else { |
| 31 | /* we do not allow even small packets from now on */ |
| 32 | q->quota = 0; |
| 33 | } |
| 34 | spin_unlock_bh("a_lock); |
| 35 | |
| 36 | return ret; |
| 37 | } |
| 38 | |
| 39 | static int |
| 40 | checkentry(const char *tablename, const void *entry, |
| 41 | const struct xt_match *match, void *matchinfo, |
| 42 | unsigned int matchsize, unsigned int hook_mask) |
| 43 | { |
| 44 | struct xt_quota_info *q = (struct xt_quota_info *)matchinfo; |
| 45 | |
| 46 | if (q->flags & ~XT_QUOTA_MASK) |
| 47 | return 0; |
| 48 | /* For SMP, we only want to use one set of counters. */ |
| 49 | q->master = q; |
| 50 | return 1; |
| 51 | } |
| 52 | |
| 53 | static struct xt_match quota_match = { |
| 54 | .name = "quota", |
| 55 | .family = AF_INET, |
| 56 | .match = match, |
| 57 | .matchsize = sizeof(struct xt_quota_info), |
| 58 | .checkentry = checkentry, |
| 59 | .me = THIS_MODULE |
| 60 | }; |
| 61 | |
| 62 | static struct xt_match quota_match6 = { |
| 63 | .name = "quota", |
| 64 | .family = AF_INET6, |
| 65 | .match = match, |
| 66 | .matchsize = sizeof(struct xt_quota_info), |
| 67 | .checkentry = checkentry, |
| 68 | .me = THIS_MODULE |
| 69 | }; |
| 70 | |
| 71 | static int __init xt_quota_init(void) |
| 72 | { |
| 73 | int ret; |
| 74 | |
| 75 | ret = xt_register_match("a_match); |
| 76 | if (ret) |
| 77 | goto err1; |
| 78 | ret = xt_register_match("a_match6); |
| 79 | if (ret) |
| 80 | goto err2; |
| 81 | return ret; |
| 82 | |
| 83 | err2: |
| 84 | xt_unregister_match("a_match); |
| 85 | err1: |
| 86 | return ret; |
| 87 | } |
| 88 | |
| 89 | static void __exit xt_quota_fini(void) |
| 90 | { |
| 91 | xt_unregister_match("a_match6); |
| 92 | xt_unregister_match("a_match); |
| 93 | } |
| 94 | |
| 95 | module_init(xt_quota_init); |
| 96 | module_exit(xt_quota_fini); |