From 89573e23db0c2d816ce29bea67c06214158f25ac Mon Sep 17 00:00:00 2001 From: "/C=EU/ST=EU/CN=Patrick McHardy/emailAddress=kaber@trash.net" Date: Mon, 9 Jul 2007 16:50:17 +0000 Subject: PATCH: Add connlimit to iptables. Signed-off-by: Jan Engelhardt --- extensions/libip6t_connlimit.c | 151 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 extensions/libip6t_connlimit.c (limited to 'extensions/libip6t_connlimit.c') diff --git a/extensions/libip6t_connlimit.c b/extensions/libip6t_connlimit.c new file mode 100644 index 0000000..fcbbcd2 --- /dev/null +++ b/extensions/libip6t_connlimit.c @@ -0,0 +1,151 @@ +/* Shared library add-on to iptables to add connection limit support. */ +#include +#include +#include +#include +#include +#include +#include +#include "../include/linux/netfilter/xt_connlimit.h" + +/* Function which prints out usage message. */ +static void connlimit_help(void) +{ + printf( +"connlimit v%s options:\n" +"[!] --connlimit-above n match if the number of existing " +" connections is (not) above n\n" +" --connlimit-mask n group hosts using mask\n" +"\n", IPTABLES_VERSION); +} + +static const struct option connlimit_opts[] = { + {"connlimit-above", 1, NULL, 1}, + {"connlimit-mask", 1, NULL, 2}, + {NULL}, +}; + +static void connlimit_init(struct ip6t_entry_match *match, unsigned int *nfc) +{ + struct xt_connlimit_info *info = (void *)match->data; + info->v6_mask[0] = + info->v6_mask[1] = + info->v6_mask[2] = + info->v6_mask[3] = 0xFFFFFFFF; +} + +static void prefix_to_netmask(u_int32_t *mask, unsigned int prefix_len) +{ + if (prefix_len == 0) { + mask[0] = mask[1] = mask[2] = mask[3] = 0; + } else if (prefix_len <= 32) { + mask[0] <<= 32 - prefix_len; + mask[1] = mask[2] = mask[3] = 0; + } else if (prefix_len <= 64) { + mask[1] <<= 32 - (prefix_len - 32); + mask[2] = mask[3] = 0; + } else if (prefix_len <= 96) { + mask[2] <<= 32 - (prefix_len - 64); + mask[3] = 0; + } else if (prefix_len <= 128) { + mask[3] <<= 32 - (prefix_len - 96); + } + mask[0] = htonl(mask[0]); + mask[1] = htonl(mask[1]); + mask[2] = htonl(mask[2]); + mask[3] = htonl(mask[3]); +} + +static int connlimit_parse(int c, char **argv, int invert, unsigned int *flags, + const struct ip6t_entry *entry, + unsigned int *nfcache, + struct ip6t_entry_match **match) +{ + struct xt_connlimit_info *info = (void *)(*match)->data; + char *err; + int i; + + if (*flags & c) + exit_error(PARAMETER_PROBLEM, + "--connlimit-above and/or --connlimit-mask may " + "only be given once"); + + switch (c) { + case 1: + check_inverse(optarg, &invert, &optind, 0); + info->limit = strtoul(argv[optind-1], NULL, 0); + info->inverse = invert; + break; + case 2: + i = strtoul(argv[optind-1], &err, 0); + if (i > 128 || *err != '\0') + exit_error(PARAMETER_PROBLEM, + "--connlimit-mask must be between 0 and 128"); + prefix_to_netmask(info->v6_mask, i); + break; + default: + return 0; + } + + *flags |= c; + return 1; +} + +/* Final check */ +static void connlimit_check(unsigned int flags) +{ + if (!(flags & 1)) + exit_error(PARAMETER_PROBLEM, + "You must specify \"--connlimit-above\""); +} + +static unsigned int count_bits(const u_int32_t *mask) +{ + unsigned int bits = 0, i; + u_int32_t tmp[4]; + + for (i = 0; i < 4; ++i) + for (tmp[i] = ~ntohl(mask[i]); tmp[i] != 0; tmp[i] >>= 1) + ++bits; + return 128 - bits; +} + +/* Prints out the matchinfo. */ +static void connlimit_print(const struct ip6t_ip6 *ip, + const struct ip6t_entry_match *match, int numeric) +{ + const struct xt_connlimit_info *info = (const void *)match->data; + + printf("#conn/%u %s %u ", count_bits(info->v6_mask), + info->inverse ? "<" : ">", info->limit); +} + +/* Saves the matchinfo in parsable form to stdout. */ +static void connlimit_save(const struct ip6t_ip6 *ip, + const struct ip6t_entry_match *match) +{ + const struct xt_connlimit_info *info = (const void *)match->data; + + printf("%s--connlimit-above %u --connlimit-mask %u ", + info->inverse ? "! " : "", info->limit, + count_bits(info->v6_mask)); +} + +static struct ip6tables_match connlimit_reg = { + .name = "connlimit", + .version = IPTABLES_VERSION, + .size = IP6T_ALIGN(sizeof(struct xt_connlimit_info)), + .userspacesize = offsetof(struct xt_connlimit_info, data), + .help = connlimit_help, + .init = connlimit_init, + .parse = connlimit_parse, + .final_check = connlimit_check, + .print = connlimit_print, + .save = connlimit_save, + .extra_opts = connlimit_opts, +}; + +static __attribute__((constructor)) void libipt_connlimit_init(void) +{ + register_match6(&connlimit_reg); +} -- cgit v1.2.3