libip6t_HL.c revision 32b8e61e4e5bd405d9ad07bf9468498dfbb19f9e
1437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall/* 2437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall * IPv6 Hop Limit Target module 3437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall * Maciej Soltysiak <solt@dns.toxicfilms.tv> 4437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall * Based on HW's ttl target 5437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall * This program is distributed under the terms of GNU GPL 6437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall */ 70fbdf6cbd4dfc633454eba2f841c123789e297adJaegeuk Kim 8437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <getopt.h> 9437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <stdbool.h> 10437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <stdio.h> 11437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <string.h> 12437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <stdlib.h> 134f267323a28c3fb50fa08256517e2dae4e347b2dJaegeuk Kim#include <xtables.h> 14437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 15437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#include <linux/netfilter_ipv6/ip6t_HL.h> 16437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 17437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall#define IP6T_HL_USED 1 18ba91378ec599572f0a47c44f4cd6a975a2f99653Sankalp Bose 19ba91378ec599572f0a47c44f4cd6a975a2f99653Sankalp Bosestatic void HL_help(void) 20ba91378ec599572f0a47c44f4cd6a975a2f99653Sankalp Bose{ 21ba91378ec599572f0a47c44f4cd6a975a2f99653Sankalp Bose printf( 22437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall"HL target options\n" 23437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall" --hl-set value Set HL to <value 0-255>\n" 24437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall" --hl-dec value Decrement HL by <value 1-255>\n" 25437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall" --hl-inc value Increment HL by <value 1-255>\n"); 26437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall} 27437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 28437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrallstatic int HL_parse(int c, char **argv, int invert, unsigned int *flags, 29437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall const void *entry, struct xt_entry_target **target) 30437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall{ 31437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall struct ip6t_HL_info *info = (struct ip6t_HL_info *) (*target)->data; 32437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall unsigned int value; 33437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 34437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall if (*flags & IP6T_HL_USED) { 35437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall xtables_error(PARAMETER_PROBLEM, 36437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall "Can't specify HL option twice"); 37437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall } 38ba91378ec599572f0a47c44f4cd6a975a2f99653Sankalp Bose 39437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall if (!optarg) 40437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall xtables_error(PARAMETER_PROBLEM, 41437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall "HL: You must specify a value"); 42437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 4346bf13d5afbdd87d0cacaa06ec159cf9546c5726Jaegeuk Kim if (xtables_check_inverse(optarg, &invert, NULL, 0, argv)) 44437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall xtables_error(PARAMETER_PROBLEM, 4546bf13d5afbdd87d0cacaa06ec159cf9546c5726Jaegeuk Kim "HL: unexpected `!'"); 4646bf13d5afbdd87d0cacaa06ec159cf9546c5726Jaegeuk Kim 4746bf13d5afbdd87d0cacaa06ec159cf9546c5726Jaegeuk Kim if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX)) 4846bf13d5afbdd87d0cacaa06ec159cf9546c5726Jaegeuk Kim xtables_error(PARAMETER_PROBLEM, 49437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall "HL: Expected value between 0 and 255"); 50437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 513c85e737308ef95629b232745d6a8d141d87cc9aJP Abgrall switch (c) { 52437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall 53437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall case '1': 54437dbf67730d2765c4dfc8539b07258e1ca3966fJP Abgrall info->mode = IP6T_HL_SET; 55 break; 56 57 case '2': 58 if (value == 0) { 59 xtables_error(PARAMETER_PROBLEM, 60 "HL: decreasing by 0?"); 61 } 62 63 info->mode = IP6T_HL_DEC; 64 break; 65 66 case '3': 67 if (value == 0) { 68 xtables_error(PARAMETER_PROBLEM, 69 "HL: increasing by 0?"); 70 } 71 72 info->mode = IP6T_HL_INC; 73 break; 74 75 default: 76 return 0; 77 78 } 79 80 info->hop_limit = value; 81 *flags |= IP6T_HL_USED; 82 83 return 1; 84} 85 86static void HL_check(unsigned int flags) 87{ 88 if (!(flags & IP6T_HL_USED)) 89 xtables_error(PARAMETER_PROBLEM, 90 "HL: You must specify an action"); 91} 92 93static void HL_save(const void *ip, const struct xt_entry_target *target) 94{ 95 const struct ip6t_HL_info *info = 96 (struct ip6t_HL_info *) target->data; 97 98 switch (info->mode) { 99 case IP6T_HL_SET: 100 printf("--hl-set "); 101 break; 102 case IP6T_HL_DEC: 103 printf("--hl-dec "); 104 break; 105 106 case IP6T_HL_INC: 107 printf("--hl-inc "); 108 break; 109 } 110 printf("%u ", info->hop_limit); 111} 112 113static void HL_print(const void *ip, const struct xt_entry_target *target, 114 int numeric) 115{ 116 const struct ip6t_HL_info *info = 117 (struct ip6t_HL_info *) target->data; 118 119 printf("HL "); 120 switch (info->mode) { 121 case IP6T_HL_SET: 122 printf("set to "); 123 break; 124 case IP6T_HL_DEC: 125 printf("decrement by "); 126 break; 127 case IP6T_HL_INC: 128 printf("increment by "); 129 break; 130 } 131 printf("%u ", info->hop_limit); 132} 133 134static const struct option HL_opts[] = { 135 {.name = "hl-set", .has_arg = true, .val = '1'}, 136 {.name = "hl-dec", .has_arg = true, .val = '2'}, 137 {.name = "hl-inc", .has_arg = true, .val = '3'}, 138 XT_GETOPT_TABLEEND, 139}; 140 141static struct xtables_target hl_tg6_reg = { 142 .name = "HL", 143 .version = XTABLES_VERSION, 144 .family = NFPROTO_IPV6, 145 .size = XT_ALIGN(sizeof(struct ip6t_HL_info)), 146 .userspacesize = XT_ALIGN(sizeof(struct ip6t_HL_info)), 147 .help = HL_help, 148 .parse = HL_parse, 149 .final_check = HL_check, 150 .print = HL_print, 151 .save = HL_save, 152 .extra_opts = HL_opts, 153}; 154 155void _init(void) 156{ 157 xtables_register_target(&hl_tg6_reg); 158} 159