diff options
Diffstat (limited to 'extensions/libip6t_MASQUERADE.c')
-rw-r--r-- | extensions/libip6t_MASQUERADE.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/extensions/libip6t_MASQUERADE.c b/extensions/libip6t_MASQUERADE.c new file mode 100644 index 00000000..eb9213ef --- /dev/null +++ b/extensions/libip6t_MASQUERADE.c @@ -0,0 +1,150 @@ +/* + * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> + * + * Based on Rusty Russell's IPv4 MASQUERADE target. Development of IPv6 NAT + * funded by Astaro. + */ + +#include <stdio.h> +#include <netdb.h> +#include <string.h> +#include <stdlib.h> +#include <getopt.h> +#include <xtables.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_PORTS = 0, + O_RANDOM, +}; + +static void MASQUERADE_help(void) +{ + printf( +"MASQUERADE target options:\n" +" --to-ports <port>[-<port>]\n" +" Port (range) to map to.\n" +" --random\n" +" Randomize source port.\n"); +} + +static const struct xt_option_entry MASQUERADE_opts[] = { + {.name = "to-ports", .id = O_TO_PORTS, .type = XTTYPE_STRING}, + {.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE}, + XTOPT_TABLEEND, +}; + +/* Parses ports */ +static void +parse_ports(const char *arg, struct nf_nat_range *r) +{ + char *end; + unsigned int port, maxport; + + r->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; + + if (!xtables_strtoui(arg, &end, &port, 0, UINT16_MAX)) + xtables_param_act(XTF_BAD_VALUE, "MASQUERADE", "--to-ports", arg); + + switch (*end) { + case '\0': + r->min_proto.tcp.port + = r->max_proto.tcp.port + = htons(port); + return; + case '-': + if (!xtables_strtoui(end + 1, NULL, &maxport, 0, UINT16_MAX)) + break; + + if (maxport < port) + break; + + r->min_proto.tcp.port = htons(port); + r->max_proto.tcp.port = htons(maxport); + return; + default: + break; + } + xtables_param_act(XTF_BAD_VALUE, "MASQUERADE", "--to-ports", arg); +} + +static void MASQUERADE_parse(struct xt_option_call *cb) +{ + const struct ip6t_entry *entry = cb->xt_entry; + struct nf_nat_range *r = 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_PORTS: + if (!portok) + xtables_error(PARAMETER_PROBLEM, + "Need TCP, UDP, SCTP or DCCP with port specification"); + parse_ports(cb->arg, r); + break; + case O_RANDOM: + r->flags |= NF_NAT_RANGE_PROTO_RANDOM; + break; + } +} + +static void +MASQUERADE_print(const void *ip, const struct xt_entry_target *target, + int numeric) +{ + const struct nf_nat_range *r = (const void *)target->data; + + if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { + printf(" masq ports: "); + printf("%hu", ntohs(r->min_proto.tcp.port)); + if (r->max_proto.tcp.port != r->min_proto.tcp.port) + printf("-%hu", ntohs(r->max_proto.tcp.port)); + } + + if (r->flags & NF_NAT_RANGE_PROTO_RANDOM) + printf(" random"); +} + +static void +MASQUERADE_save(const void *ip, const struct xt_entry_target *target) +{ + const struct nf_nat_range *r = (const void *)target->data; + + if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { + printf(" --to-ports %hu", ntohs(r->min_proto.tcp.port)); + if (r->max_proto.tcp.port != r->min_proto.tcp.port) + printf("-%hu", ntohs(r->max_proto.tcp.port)); + } + + if (r->flags & NF_NAT_RANGE_PROTO_RANDOM) + printf(" --random"); +} + +static struct xtables_target masquerade_tg_reg = { + .name = "MASQUERADE", + .version = XTABLES_VERSION, + .family = NFPROTO_IPV6, + .size = XT_ALIGN(sizeof(struct nf_nat_range)), + .userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)), + .help = MASQUERADE_help, + .x6_parse = MASQUERADE_parse, + .print = MASQUERADE_print, + .save = MASQUERADE_save, + .x6_options = MASQUERADE_opts, +}; + +void _init(void) +{ + xtables_register_target(&masquerade_tg_reg); +} |