diff options
author | Jan Engelhardt <jengelh@medozas.de> | 2007-07-31 16:47:38 +0000 |
---|---|---|
committer | Yasuyuki KOZAKAI <yasuyuki@netfilter.org> | 2007-07-31 16:47:38 +0000 |
commit | 6053fe00dda962fbabe158291a88b1a92aadc215 (patch) | |
tree | 7bd7e786bcedfbd61db134e987924610f4074ac1 /extensions/libxt_connlimit.c | |
parent | 661f112072bc13a1625c4eb5983695e122ea97da (diff) |
Moves libip{,6}t_connlimit to libxt.
Also fixes an option parsing bug (connlimit_parse() may receive
a 'c' that is not from the connlimit options table).
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Diffstat (limited to 'extensions/libxt_connlimit.c')
-rw-r--r-- | extensions/libxt_connlimit.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/extensions/libxt_connlimit.c b/extensions/libxt_connlimit.c new file mode 100644 index 00000000..28a9caa0 --- /dev/null +++ b/extensions/libxt_connlimit.c @@ -0,0 +1,217 @@ +/* Shared library add-on to iptables to add connection limit support. */ +#include <stdio.h> +#include <netdb.h> +#include <string.h> +#include <stdlib.h> +#include <stddef.h> +#include <getopt.h> +#include <iptables.h> +#include "../include/linux/netfilter/xt_connlimit.h" + +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, 'A'}, + {"connlimit-mask", 1, NULL, 'M'}, + {NULL}, +}; + +static void connlimit_init(struct ipt_entry_match *match, unsigned int *nfc) +{ + struct xt_connlimit_info *info = (void *)match->data; + info->v4_mask = 0xFFFFFFFFUL; +} + +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, + struct xt_connlimit_info *info, unsigned int family) +{ + char *err; + int i; + + switch (c) { + case 'A': + if (*flags & 0x1) + exit_error(PARAMETER_PROBLEM, + "--connlimit-above may be given only once"); + *flags |= 0x1; + check_inverse(optarg, &invert, &optind, 0); + info->limit = strtoul(argv[optind-1], NULL, 0); + info->inverse = invert; + break; + case 'M': + if (*flags & 0x2) + exit_error(PARAMETER_PROBLEM, + "--connlimit-mask may be given only once"); + + *flags |= 0x2; + i = strtoul(argv[optind-1], &err, 0); + if (family == AF_INET6) { + if (i > 128 || *err != '\0') + exit_error(PARAMETER_PROBLEM, + "--connlimit-mask must be between " + "0 and 128"); + prefix_to_netmask(info->v6_mask, i); + } else { + if (i > 32 || *err != '\0') + exit_error(PARAMETER_PROBLEM, + "--connlimit-mask must be between " + "0 and 32"); + if (i == 0) + info->v4_mask = 0; + else + info->v4_mask = htonl(0xFFFFFFFF << (32 - i)); + } + break; + default: + return 0; + } + + return 1; +} + +static int connlimit_parse4(int c, char **argv, int invert, + unsigned int *flags, const void *entry, + unsigned int *nfcache, + struct xt_entry_match **match) +{ + return connlimit_parse(c, argv, invert, flags, + (void *)(*match)->data, AF_INET); +} + +static int connlimit_parse6(int c, char **argv, int invert, + unsigned int *flags, const void *entry, + unsigned int *nfcache, + struct xt_entry_match **match) +{ + return connlimit_parse(c, argv, invert, flags, + (void *)(*match)->data, AF_INET6); +} + +static void connlimit_check(unsigned int flags) +{ + if (!(flags & 0x1)) + exit_error(PARAMETER_PROBLEM, + "You must specify \"--connlimit-above\""); +} + +static unsigned int count_bits4(u_int32_t mask) +{ + unsigned int bits = 0; + + for (mask = ~ntohl(mask); mask != 0; mask >>= 1) + ++bits; + + return 32 - bits; +} + +static unsigned int count_bits6(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; +} + +static void connlimit_print4(const void *ip, + const struct xt_entry_match *match, int numeric) +{ + const struct xt_connlimit_info *info = (const void *)match->data; + + printf("#conn/%u %s %u ", count_bits4(info->v4_mask), + info->inverse ? "<" : ">", info->limit); +} + +static void connlimit_print6(const void *ip, + const struct xt_entry_match *match, int numeric) +{ + const struct xt_connlimit_info *info = (const void *)match->data; + printf("#conn/%u %s %u ", count_bits6(info->v6_mask), + info->inverse ? "<" : ">", info->limit); +} + +static void connlimit_save4(const void *ip, const struct xt_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_bits4(info->v4_mask)); +} + +static void connlimit_save6(const void *ip, const struct xt_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_bits6(info->v6_mask)); +} + +static struct xtables_match connlimit_reg4 = { + .name = "connlimit", + .family = AF_INET, + .version = IPTABLES_VERSION, + .size = XT_ALIGN(sizeof(struct xt_connlimit_info)), + .userspacesize = offsetof(struct xt_connlimit_info, data), + .help = connlimit_help, + .init = connlimit_init, + .parse = connlimit_parse4, + .final_check = connlimit_check, + .print = connlimit_print4, + .save = connlimit_save4, + .extra_opts = connlimit_opts, +}; + +static struct xtables_match connlimit_reg6 = { + .name = "connlimit", + .family = AF_INET6, + .version = IPTABLES_VERSION, + .size = XT_ALIGN(sizeof(struct xt_connlimit_info)), + .userspacesize = offsetof(struct xt_connlimit_info, data), + .help = connlimit_help, + .init = connlimit_init, + .parse = connlimit_parse6, + .final_check = connlimit_check, + .print = connlimit_print6, + .save = connlimit_save6, + .extra_opts = connlimit_opts, +}; + +void _init(void) +{ + xtables_register_match(&connlimit_reg4); + xtables_register_match(&connlimit_reg6); +} |