| Gerd Knorr | d2d0263 | 2000-12-18 06:07:23 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add state tracking support. */ |
| 2 | #include <stdio.h> |
| 3 | #include <netdb.h> |
| 4 | #include <string.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <getopt.h> |
| 7 | #include <iptables.h> |
| 8 | #include <linux/netfilter_ipv4/ip_conntrack.h> |
| 9 | #include <linux/netfilter_ipv4/ipt_iplimit.h> |
| 10 | |
| 11 | /* Function which prints out usage message. */ |
| 12 | static void |
| 13 | help(void) |
| 14 | { |
| 15 | printf( |
| 16 | "iplimit v%s options:\n" |
| 17 | "[!] --iplimit-above n match if the number of existing tcp connections is (not) above n\n" |
| 18 | " --iplimit-mask n group hosts using mask\n" |
| 19 | "\n", NETFILTER_VERSION); |
| 20 | } |
| 21 | |
| 22 | static struct option opts[] = { |
| 23 | { "iplimit-above", 1, 0, '1' }, |
| 24 | { "iplimit-mask", 1, 0, '2' }, |
| 25 | {0} |
| 26 | }; |
| 27 | |
| 28 | /* Initialize the match. */ |
| 29 | static void |
| 30 | init(struct ipt_entry_match *m, unsigned int *nfcache) |
| 31 | { |
| 32 | /* Can't cache this */ |
| 33 | *nfcache |= NFC_UNKNOWN; |
| 34 | } |
| 35 | |
| 36 | /* Function which parses command options; returns true if it |
| 37 | ate an option */ |
| 38 | static int |
| 39 | parse(int c, char **argv, int invert, unsigned int *flags, |
| 40 | const struct ipt_entry *entry, |
| 41 | unsigned int *nfcache, |
| 42 | struct ipt_entry_match **match) |
| 43 | { |
| 44 | struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)(*match)->data; |
| 45 | |
| 46 | if (0 == (*flags & 2)) { |
| 47 | /* set default mask unless we've already seen a mask option */ |
| 48 | info->mask = htonl(0xFFFFFFFF); |
| 49 | } |
| 50 | |
| 51 | switch (c) { |
| 52 | case '1': |
| 53 | if (check_inverse(optarg, &invert)) |
| 54 | optind++; |
| 55 | info->limit = atoi(argv[optind-1]); |
| 56 | info->inverse = invert; |
| 57 | *flags |= 1; |
| 58 | break; |
| 59 | |
| 60 | case '2': |
| 61 | info->mask = htonl(0xFFFFFFFF << (32 - atoi(argv[optind-1]))); |
| 62 | *flags |= 2; |
| 63 | break; |
| 64 | |
| 65 | default: |
| 66 | return 0; |
| 67 | } |
| 68 | |
| 69 | return 1; |
| 70 | } |
| 71 | |
| 72 | /* Final check */ |
| 73 | static void final_check(unsigned int flags) |
| 74 | { |
| 75 | if (!flags & 1) |
| 76 | exit_error(PARAMETER_PROBLEM, "You must specify `--iplimit-above'"); |
| 77 | } |
| 78 | |
| 79 | static int |
| 80 | count_bits(u_int32_t mask) |
| 81 | { |
| 82 | int i, bits; |
| 83 | |
| 84 | for (bits = 0, i = 31; i >= 0; i--) { |
| 85 | if (mask & htonl((u_int32_t)1 << i)) { |
| 86 | bits++; |
| 87 | continue; |
| 88 | } |
| 89 | break; |
| 90 | } |
| 91 | return bits; |
| 92 | } |
| 93 | |
| 94 | /* Prints out the matchinfo. */ |
| 95 | static void |
| 96 | print(const struct ipt_ip *ip, |
| 97 | const struct ipt_entry_match *match, |
| 98 | int numeric) |
| 99 | { |
| 100 | struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)match->data; |
| 101 | |
| 102 | printf("#conn/%d %s %d", count_bits(info->mask), |
| 103 | info->inverse ? "<" : ">", info->limit); |
| 104 | } |
| 105 | |
| 106 | /* Saves the matchinfo in parsable form to stdout. */ |
| 107 | static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match) |
| 108 | { |
| 109 | struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)match->data; |
| 110 | |
| 111 | printf("%s--iplimit-above %d",info->inverse ? "! " : "",info->limit); |
| 112 | printf(" --iplimit-mask %d",count_bits(info->mask)); |
| 113 | } |
| 114 | |
| 115 | struct iptables_match iplimit |
| 116 | = { NULL, |
| 117 | "iplimit", |
| 118 | NETFILTER_VERSION, |
| 119 | IPT_ALIGN(sizeof(struct ipt_iplimit_info)), |
| 120 | IPT_ALIGN(sizeof(struct ipt_iplimit_info)), |
| 121 | &help, |
| 122 | &init, |
| 123 | &parse, |
| 124 | &final_check, |
| 125 | &print, |
| 126 | &save, |
| 127 | opts |
| 128 | }; |
| 129 | |
| 130 | void _init(void) |
| 131 | { |
| 132 | register_match(&iplimit); |
| 133 | } |