| /* Shared library add-on to iptables to add ROUTE target support. |
| * Author : Cédric de Launois, <delaunois@info.ucl.ac.be> |
| */ |
| |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <getopt.h> |
| #include <iptables.h> |
| #include <net/if.h> |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv4/ipt_ROUTE.h> |
| |
| /* Function which prints out usage message. */ |
| static void |
| help(void) |
| { |
| printf( |
| "ROUTE target v%s options:\n" |
| " --oif \tifname \t\tSend the packet out using `ifname' network interface\n" |
| " --iif \tifname \t\tChange the packet's incoming interface to `ifname'\n" |
| " --gw \tip \t\tRoute the packet via this gateway\n" |
| "\n", |
| IPTABLES_VERSION); |
| } |
| |
| static struct option opts[] = { |
| { "oif", 1, 0, '1' }, |
| { "iif", 1, 0, '2' }, |
| { "gw", 1, 0, '3' }, |
| { 0 } |
| }; |
| |
| /* Initialize the target. */ |
| static void |
| init(struct ipt_entry_target *t, unsigned int *nfcache) |
| { |
| struct ipt_route_target_info *route_info = |
| (struct ipt_route_target_info*)t->data; |
| |
| route_info->oif[0] = '\0'; |
| route_info->iif[0] = '\0'; |
| route_info->gw = 0; |
| } |
| |
| |
| #define IPT_ROUTE_OPT_IF 0x01 |
| #define IPT_ROUTE_OPT_GW 0x02 |
| |
| /* Function which parses command options; returns true if it |
| ate an option */ |
| static int |
| parse(int c, char **argv, int invert, unsigned int *flags, |
| const struct ipt_entry *entry, |
| struct ipt_entry_target **target) |
| { |
| struct ipt_route_target_info *route_info = |
| (struct ipt_route_target_info*)(*target)->data; |
| |
| switch (c) { |
| case '1': |
| if (*flags & IPT_ROUTE_OPT_IF) |
| exit_error(PARAMETER_PROBLEM, |
| "Can't specify --oif twice or --oif with --iif"); |
| |
| if (check_inverse(optarg, &invert, NULL, 0)) |
| exit_error(PARAMETER_PROBLEM, |
| "Unexpected `!' after --oif"); |
| |
| if (strlen(optarg) > sizeof(route_info->oif) - 1) |
| exit_error(PARAMETER_PROBLEM, |
| "Maximum interface name length %u", |
| sizeof(route_info->oif) - 1); |
| |
| strcpy(route_info->oif, optarg); |
| *flags |= IPT_ROUTE_OPT_IF; |
| break; |
| |
| case '2': |
| if (*flags & IPT_ROUTE_OPT_IF) |
| exit_error(PARAMETER_PROBLEM, |
| "Can't specify --iif twice or --iif with --oif"); |
| |
| if (check_inverse(optarg, &invert, NULL, 0)) |
| exit_error(PARAMETER_PROBLEM, |
| "Unexpected `!' after --iif"); |
| |
| if (strlen(optarg) > sizeof(route_info->iif) - 1) |
| exit_error(PARAMETER_PROBLEM, |
| "Maximum interface name length %u", |
| sizeof(route_info->iif) - 1); |
| |
| strcpy(route_info->iif, optarg); |
| *flags |= IPT_ROUTE_OPT_IF; |
| break; |
| |
| case '3': |
| if (*flags & IPT_ROUTE_OPT_GW) |
| exit_error(PARAMETER_PROBLEM, |
| "Can't specify --gw twice"); |
| |
| if (!inet_aton(optarg, (struct in_addr*)&route_info->gw)) { |
| exit_error(PARAMETER_PROBLEM, |
| "Invalid IP address %s", |
| optarg); |
| } |
| |
| *flags |= IPT_ROUTE_OPT_GW; |
| break; |
| |
| default: |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| |
| static void |
| final_check(unsigned int flags) |
| { |
| if (!flags) |
| exit_error(PARAMETER_PROBLEM, |
| "ROUTE target: one parameter is required"); |
| } |
| |
| |
| /* Prints out the targinfo. */ |
| static void |
| print(const struct ipt_ip *ip, |
| const struct ipt_entry_target *target, |
| int numeric) |
| { |
| const struct ipt_route_target_info *route_info |
| = (const struct ipt_route_target_info *)target->data; |
| |
| printf("ROUTE "); |
| |
| if (route_info->oif[0]) |
| printf("oif %s ", route_info->oif); |
| |
| if (route_info->iif[0]) |
| printf("iif %s ", route_info->iif); |
| |
| if (route_info->gw) { |
| struct in_addr ip = { route_info->gw }; |
| printf("gw %s ", inet_ntoa(ip)); |
| } |
| } |
| |
| |
| static void save(const struct ipt_ip *ip, |
| const struct ipt_entry_target *target) |
| { |
| const struct ipt_route_target_info *route_info |
| = (const struct ipt_route_target_info *)target->data; |
| |
| if (route_info->oif[0]) |
| printf("--oif %s ", route_info->oif); |
| |
| if (route_info->iif[0]) |
| printf("--iif %s ", route_info->iif); |
| |
| if (route_info->gw) { |
| struct in_addr ip = { route_info->gw }; |
| printf("--gw %s ", inet_ntoa(ip)); |
| } |
| } |
| |
| |
| static |
| struct iptables_target route |
| = { NULL, |
| "ROUTE", |
| IPTABLES_VERSION, |
| IPT_ALIGN(sizeof(struct ipt_route_target_info)), |
| IPT_ALIGN(sizeof(struct ipt_route_target_info)), |
| &help, |
| &init, |
| &parse, |
| &final_check, |
| &print, |
| &save, |
| opts |
| }; |
| |
| void _init(void) |
| { |
| register_target(&route); |
| } |