diff options
Diffstat (limited to 'extensions/libip6t_DNAT.c')
| -rw-r--r-- | extensions/libip6t_DNAT.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/extensions/libip6t_DNAT.c b/extensions/libip6t_DNAT.c new file mode 100644 index 00000000..a5969c36 --- /dev/null +++ b/extensions/libip6t_DNAT.c @@ -0,0 +1,247 @@ +/* + * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> + * + * Based on Rusty Russell's IPv4 DNAT target. Development of IPv6 NAT + * funded by Astaro. + */ + +#include <stdio.h> +#include <netdb.h> +#include <string.h> +#include <stdlib.h> +#include <xtables.h> +#include <iptables.h> +#include <limits.h> /* INT_MAX in ip_tables.h */ +#include <linux/netfilter_ipv6/ip6_tables.h> +#include <linux/netfilter/nf_nat.h> + +enum { + O_TO_DEST = 0, + O_RANDOM, + O_PERSISTENT, + O_X_TO_DEST, + F_TO_DEST = 1 << O_TO_DEST, + F_RANDOM = 1 << O_RANDOM, + F_X_TO_DEST = 1 << O_X_TO_DEST, +}; + +static void DNAT_help(void) +{ + printf( +"DNAT target options:\n" +" --to-dest [<ipaddr>[-<ipaddr>]][:port[-port]]\n" +" Address to map source to.\n" +"[--random] [--persistent]\n"); +} + +static const struct xt_option_entry DNAT_opts[] = { + {.name = "to-dest", .id = O_TO_DEST, .type = XTTYPE_STRING, + .flags = XTOPT_MAND | XTOPT_MULTI}, + {.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE}, + {.name = "persistent", .id = O_PERSISTENT, .type = XTTYPE_NONE}, + XTOPT_TABLEEND, +}; + +/* Ranges expected in network order. */ +static void +parse_to(const char *orig_arg, int portok, struct nf_nat_range *range) +{ + char *arg, *start, *end = NULL, *colon = NULL, *dash, *error; + const struct in6_addr *ip; + + arg = strdup(orig_arg); + if (arg == NULL) + xtables_error(RESOURCE_PROBLEM, "strdup"); + + start = strchr(arg, '['); + if (start == NULL) + start = arg; + else { + start++; + end = strchr(start, ']'); + if (end == NULL) + xtables_error(PARAMETER_PROBLEM, + "Invalid address format"); + + *end = '\0'; + colon = strchr(end + 1, ':'); + } + + if (colon) { + int port; + + if (!portok) + xtables_error(PARAMETER_PROBLEM, + "Need TCP, UDP, SCTP or DCCP with port specification"); + + range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; + + port = atoi(colon+1); + if (port <= 0 || port > 65535) + xtables_error(PARAMETER_PROBLEM, + "Port `%s' not valid\n", colon+1); + + error = strchr(colon+1, ':'); + if (error) + xtables_error(PARAMETER_PROBLEM, + "Invalid port:port syntax - use dash\n"); + + dash = strchr(colon, '-'); + if (!dash) { + range->min_proto.tcp.port + = range->max_proto.tcp.port + = htons(port); + } else { + int maxport; + + maxport = atoi(dash + 1); + if (maxport <= 0 || maxport > 65535) + xtables_error(PARAMETER_PROBLEM, + "Port `%s' not valid\n", dash+1); + if (maxport < port) + /* People are stupid. */ + xtables_error(PARAMETER_PROBLEM, + "Port range `%s' funky\n", colon+1); + range->min_proto.tcp.port = htons(port); + range->max_proto.tcp.port = htons(maxport); + } + /* Starts with a colon? No IP info...*/ + if (colon == arg) { + free(arg); + return; + } + *colon = '\0'; + } + + range->flags |= NF_NAT_RANGE_MAP_IPS; + dash = strchr(start, '-'); + if (colon && dash && dash > colon) + dash = NULL; + + if (dash) + *dash = '\0'; + + ip = xtables_numeric_to_ip6addr(start); + if (!ip) + xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n", + start); + range->min_addr.in6 = *ip; + if (dash) { + ip = xtables_numeric_to_ip6addr(dash + 1); + if (!ip) + xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n", + dash+1); + range->max_addr.in6 = *ip; + } else + range->max_addr = range->min_addr; + + free(arg); + return; +} + +static void DNAT_parse(struct xt_option_call *cb) +{ + const struct ip6t_entry *entry = cb->xt_entry; + struct nf_nat_range *range = cb->data; + int portok; + + if (entry->ipv6.proto == IPPROTO_TCP || + entry->ipv6.proto == IPPROTO_UDP || + entry->ipv6.proto == IPPROTO_SCTP || + entry->ipv6.proto == IPPROTO_DCCP || + entry->ipv6.proto == IPPROTO_ICMP) + portok = 1; + else + portok = 0; + + xtables_option_parse(cb); + switch (cb->entry->id) { + case O_TO_DEST: + if (cb->xflags & F_X_TO_DEST) { + if (!kernel_version) + get_kernel_version(); + if (kernel_version > LINUX_VERSION(2, 6, 10)) + xtables_error(PARAMETER_PROBLEM, + "DNAT: Multiple --to-source not supported"); + } + parse_to(cb->arg, portok, range); + break; + case O_PERSISTENT: + range->flags |= NF_NAT_RANGE_PERSISTENT; + break; + } +} + +static void DNAT_fcheck(struct xt_fcheck_call *cb) +{ + static const unsigned int f = F_TO_DEST | F_RANDOM; + struct nf_nat_range *mr = cb->data; + + if ((cb->xflags & f) == f) + mr->flags |= NF_NAT_RANGE_PROTO_RANDOM; +} + +static void print_range(const struct nf_nat_range *range) +{ + if (range->flags & NF_NAT_RANGE_MAP_IPS) { + if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) + printf("["); + printf("%s", xtables_ip6addr_to_numeric(&range->min_addr.in6)); + if (memcmp(&range->min_addr, &range->max_addr, + sizeof(range->min_addr))) + printf("-%s", xtables_ip6addr_to_numeric(&range->max_addr.in6)); + if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) + printf("]"); + } + if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { + printf(":"); + printf("%hu", ntohs(range->min_proto.tcp.port)); + if (range->max_proto.tcp.port != range->min_proto.tcp.port) + printf("-%hu", ntohs(range->max_proto.tcp.port)); + } +} + +static void DNAT_print(const void *ip, const struct xt_entry_target *target, + int numeric) +{ + const struct nf_nat_range *range = (const void *)target->data; + + printf(" to:"); + print_range(range); + if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) + printf(" random"); + if (range->flags & NF_NAT_RANGE_PERSISTENT) + printf(" persistent"); +} + +static void DNAT_save(const void *ip, const struct xt_entry_target *target) +{ + const struct nf_nat_range *range = (const void *)target->data; + + printf(" --to-source "); + print_range(range); + if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) + printf(" --random"); + if (range->flags & NF_NAT_RANGE_PERSISTENT) + printf(" --persistent"); +} + +static struct xtables_target snat_tg_reg = { + .name = "DNAT", + .version = XTABLES_VERSION, + .family = NFPROTO_IPV6, + .revision = 1, + .size = XT_ALIGN(sizeof(struct nf_nat_range)), + .userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)), + .help = DNAT_help, + .x6_parse = DNAT_parse, + .x6_fcheck = DNAT_fcheck, + .print = DNAT_print, + .save = DNAT_save, + .x6_options = DNAT_opts, +}; + +void _init(void) +{ + xtables_register_target(&snat_tg_reg); +} |