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75 lines
1.8 KiB
75 lines
1.8 KiB
#include <stdio.h> |
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#include <xtables.h> |
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#include <linux/netfilter/xt_tcpmss.h> |
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enum { |
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O_TCPMSS = 0, |
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}; |
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static void tcpmss_help(void) |
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{ |
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printf( |
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"tcpmss match options:\n" |
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"[!] --mss value[:value] Match TCP MSS range.\n" |
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" (only valid for TCP SYN or SYN/ACK packets)\n"); |
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} |
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static const struct xt_option_entry tcpmss_opts[] = { |
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{.name = "mss", .id = O_TCPMSS, .type = XTTYPE_UINT16RC, |
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.flags = XTOPT_MAND | XTOPT_INVERT}, |
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XTOPT_TABLEEND, |
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}; |
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static void tcpmss_parse(struct xt_option_call *cb) |
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{ |
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struct xt_tcpmss_match_info *mssinfo = cb->data; |
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xtables_option_parse(cb); |
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mssinfo->mss_min = cb->val.u16_range[0]; |
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mssinfo->mss_max = mssinfo->mss_min; |
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if (cb->nvals == 2) |
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mssinfo->mss_max = cb->val.u16_range[1]; |
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if (cb->invert) |
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mssinfo->invert = 1; |
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} |
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static void |
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tcpmss_print(const void *ip, const struct xt_entry_match *match, int numeric) |
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{ |
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const struct xt_tcpmss_match_info *info = (void *)match->data; |
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printf(" tcpmss match %s", info->invert ? "!" : ""); |
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if (info->mss_min == info->mss_max) |
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printf("%u", info->mss_min); |
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else |
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printf("%u:%u", info->mss_min, info->mss_max); |
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} |
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static void tcpmss_save(const void *ip, const struct xt_entry_match *match) |
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{ |
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const struct xt_tcpmss_match_info *info = (void *)match->data; |
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printf("%s --mss ", info->invert ? " !" : ""); |
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if (info->mss_min == info->mss_max) |
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printf("%u", info->mss_min); |
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else |
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printf("%u:%u", info->mss_min, info->mss_max); |
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} |
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static struct xtables_match tcpmss_match = { |
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.family = NFPROTO_UNSPEC, |
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.name = "tcpmss", |
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.version = XTABLES_VERSION, |
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.size = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
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.userspacesize = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
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.help = tcpmss_help, |
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.print = tcpmss_print, |
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.save = tcpmss_save, |
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.x6_parse = tcpmss_parse, |
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.x6_options = tcpmss_opts, |
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}; |
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void _init(void) |
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{ |
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xtables_register_match(&tcpmss_match); |
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}
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