From 14d77c8aa29a7b361d7830e40a7f75a05b29f717 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 19 Jan 2022 01:59:09 +0100 Subject: extensions: Merge IPv4 and IPv6 DNAT targets Make parse_to() family-aware so it serves for both IPv4 and IPv6. Have a core _DNAT_parse() function which parses into the most modern (nf_nat_range2) data structure and a bunch of wrappers to copy into legacy data structures if needed. Treat other callbacks analogous. Signed-off-by: Phil Sutter --- extensions/libxt_DNAT.c | 224 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 183 insertions(+), 41 deletions(-) (limited to 'extensions/libxt_DNAT.c') diff --git a/extensions/libxt_DNAT.c b/extensions/libxt_DNAT.c index 9a179919..7f7c322c 100644 --- a/extensions/libxt_DNAT.c +++ b/extensions/libxt_DNAT.c @@ -1,3 +1,10 @@ +/* + * Copyright (c) 2011 Patrick McHardy + * + * Based on Rusty Russell's IPv4 DNAT target. Development of IPv6 NAT + * funded by Astaro. + */ + #include #include #include @@ -7,6 +14,7 @@ #include /* INT_MAX in ip_tables.h */ #include #include +#include #include #define TO_IPV4_MRC(ptr) ((const struct nf_nat_ipv4_multi_range_compat *)(ptr)) @@ -119,18 +127,36 @@ parse_ports(const char *arg, bool portok, struct nf_nat_range2 *range) /* Ranges expected in network order. */ static void -parse_to(const char *orig_arg, bool portok, struct nf_nat_range2 *range) +parse_to(const char *orig_arg, bool portok, + struct nf_nat_range2 *range, int family) { - char *arg, *colon, *dash; + char *arg, *start, *end, *colon, *dash; arg = xtables_strdup(orig_arg); - colon = strchr(arg, ':'); + start = strchr(arg, '['); + if (!start) { + start = arg; + /* Lets assume one colon is port information. + * Otherwise its an IPv6 address */ + colon = strchr(arg, ':'); + if (colon && strchr(colon + 1, ':')) + colon = NULL; + } else { + start++; + end = strchr(start, ']'); + if (end == NULL || family == AF_INET) + xtables_error(PARAMETER_PROBLEM, + "Invalid address format"); + + *end = '\0'; + colon = strchr(end + 1, ':'); + } if (colon) { parse_ports(colon + 1, portok, range); - /* Starts with a colon? No IP info...*/ - if (colon == arg) { + /* Starts with colon or [] colon? No IP info...*/ + if (colon == arg || colon == arg + 2) { free(arg); return; } @@ -138,20 +164,20 @@ parse_to(const char *orig_arg, bool portok, struct nf_nat_range2 *range) } range->flags |= NF_NAT_RANGE_MAP_IPS; - dash = strchr(arg, '-'); + dash = strchr(start, '-'); if (colon && dash && dash > colon) dash = NULL; if (dash) *dash = '\0'; - if (!inet_pton(AF_INET, arg, &range->min_addr)) + if (!inet_pton(family, start, &range->min_addr)) xtables_error(PARAMETER_PROBLEM, - "Bad IP address \"%s\"\n", arg); + "Bad IP address \"%s\"", arg); if (dash) { - if (!inet_pton(AF_INET, dash + 1, &range->max_addr)) + if (!inet_pton(family, dash + 1, &range->max_addr)) xtables_error(PARAMETER_PROBLEM, - "Bad IP address \"%s\"\n", dash + 1); + "Bad IP address \"%s\"", dash + 1); } else { range->max_addr = range->min_addr; } @@ -160,7 +186,7 @@ parse_to(const char *orig_arg, bool portok, struct nf_nat_range2 *range) } static void __DNAT_parse(struct xt_option_call *cb, __u16 proto, - struct nf_nat_range2 *range) + struct nf_nat_range2 *range, int family) { bool portok = proto == IPPROTO_TCP || proto == IPPROTO_UDP || @@ -171,7 +197,7 @@ static void __DNAT_parse(struct xt_option_call *cb, __u16 proto, xtables_option_parse(cb); switch (cb->entry->id) { case O_TO_DEST: - parse_to(cb->arg, portok, range); + parse_to(cb->arg, portok, range, family); break; case O_PERSISTENT: range->flags |= NF_NAT_RANGE_PERSISTENT; @@ -185,7 +211,7 @@ static void DNAT_parse(struct xt_option_call *cb) const struct ipt_entry *entry = cb->xt_entry; struct nf_nat_range2 range = {}; - __DNAT_parse(cb, entry->ip.proto, &range); + __DNAT_parse(cb, entry->ip.proto, &range, AF_INET); switch (cb->entry->id) { case O_TO_DEST: @@ -200,32 +226,47 @@ static void DNAT_parse(struct xt_option_call *cb) } } -static void DNAT_fcheck(struct xt_fcheck_call *cb) +static void __DNAT_fcheck(struct xt_fcheck_call *cb, unsigned int *flags) { static const unsigned int f = F_TO_DEST | F_RANDOM; - struct nf_nat_ipv4_multi_range_compat *mr = cb->data; if ((cb->xflags & f) == f) - mr->range[0].flags |= NF_NAT_RANGE_PROTO_RANDOM; + *flags |= NF_NAT_RANGE_PROTO_RANDOM; +} + +static void DNAT_fcheck(struct xt_fcheck_call *cb) +{ + struct nf_nat_ipv4_multi_range_compat *mr = cb->data; mr->rangesize = 1; if (mr->range[0].flags & NF_NAT_RANGE_PROTO_OFFSET) xtables_error(PARAMETER_PROBLEM, "Shifted portmap ranges not supported with this kernel"); + + __DNAT_fcheck(cb, &mr->range[0].flags); } -static char *sprint_range(const struct nf_nat_range2 *r) +static char *sprint_range(const struct nf_nat_range2 *r, int family) { - static char buf[INET_ADDRSTRLEN * 2 + 1 + 6 * 3]; + bool brackets = family == AF_INET6 && + r->flags & NF_NAT_RANGE_PROTO_SPECIFIED; + static char buf[INET6_ADDRSTRLEN * 2 + 3 + 6 * 3]; + + buf[0] = '\0'; if (r->flags & NF_NAT_RANGE_MAP_IPS) { - sprintf(buf, "%s", xtables_ipaddr_to_numeric(&r->min_addr.in)); - if (memcmp(&r->min_addr, &r->max_addr, sizeof(r->min_addr))) - sprintf(buf + strlen(buf), "-%s", - xtables_ipaddr_to_numeric(&r->max_addr.in)); - } else { - buf[0] = '\0'; + if (brackets) + strcat(buf, "["); + inet_ntop(family, &r->min_addr, + buf + strlen(buf), INET6_ADDRSTRLEN); + if (memcmp(&r->min_addr, &r->max_addr, sizeof(r->min_addr))) { + strcat(buf, "-"); + inet_ntop(family, &r->max_addr, + buf + strlen(buf), INET6_ADDRSTRLEN); + } + if (brackets) + strcat(buf, "]"); } if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { sprintf(buf + strlen(buf), ":%hu", @@ -240,11 +281,12 @@ static char *sprint_range(const struct nf_nat_range2 *r) return buf; } -static void __DNAT_print(const struct nf_nat_range2 *r, bool save) +static void __DNAT_print(const struct nf_nat_range2 *r, bool save, int family) { const char *dashdash = save ? "--" : ""; - printf(" %s%s", save ? "--to-destination " : "to:", sprint_range(r)); + printf(" %s%s", save ? "--to-destination " : "to:", + sprint_range(r, family)); if (r->flags & NF_NAT_RANGE_PROTO_RANDOM) printf(" %srandom", dashdash); if (r->flags & NF_NAT_RANGE_PERSISTENT) @@ -256,19 +298,20 @@ static void DNAT_print(const void *ip, const struct xt_entry_target *target, { struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data); - __DNAT_print(&range, false); + __DNAT_print(&range, false, AF_INET); } static void DNAT_save(const void *ip, const struct xt_entry_target *target) { struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data); - __DNAT_print(&range, true); + __DNAT_print(&range, true, AF_INET); } -static int __DNAT_xlate(struct xt_xlate *xl, const struct nf_nat_range2 *r) +static int +__DNAT_xlate(struct xt_xlate *xl, const struct nf_nat_range2 *r, int family) { - char *range_str = sprint_range(r); + char *range_str = sprint_range(r, family); const char *sep = " "; /* shifted portmap ranges are not supported by nftables */ @@ -295,40 +338,109 @@ static int DNAT_xlate(struct xt_xlate *xl, struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(params->target->data); - return __DNAT_xlate(xl, &range); + return __DNAT_xlate(xl, &range, AF_INET); } static void DNAT_parse_v2(struct xt_option_call *cb) { const struct ipt_entry *entry = cb->xt_entry; - __DNAT_parse(cb, entry->ip.proto, cb->data); + __DNAT_parse(cb, entry->ip.proto, cb->data, AF_INET); } static void DNAT_fcheck_v2(struct xt_fcheck_call *cb) { - static const unsigned int f = F_TO_DEST | F_RANDOM; - struct nf_nat_range2 *range = cb->data; - - if ((cb->xflags & f) == f) - range->flags |= NF_NAT_RANGE_PROTO_RANDOM; + __DNAT_fcheck(cb, &((struct nf_nat_range2 *)cb->data)->flags); } static void DNAT_print_v2(const void *ip, const struct xt_entry_target *target, int numeric) { - __DNAT_print((const void *)target->data, false); + __DNAT_print((const void *)target->data, false, AF_INET); } static void DNAT_save_v2(const void *ip, const struct xt_entry_target *target) { - __DNAT_print((const void *)target->data, true); + __DNAT_print((const void *)target->data, true, AF_INET); } static int DNAT_xlate_v2(struct xt_xlate *xl, - const struct xt_xlate_tg_params *params) + const struct xt_xlate_tg_params *params) +{ + return __DNAT_xlate(xl, (const void *)params->target->data, AF_INET); +} + +static void DNAT_parse6(struct xt_option_call *cb) +{ + const struct ip6t_entry *entry = cb->xt_entry; + struct nf_nat_range *range_v1 = (void *)cb->data; + struct nf_nat_range2 range = {}; + + memcpy(&range, range_v1, sizeof(*range_v1)); + __DNAT_parse(cb, entry->ipv6.proto, &range, AF_INET6); + memcpy(range_v1, &range, sizeof(*range_v1)); +} + +static void DNAT_fcheck6(struct xt_fcheck_call *cb) +{ + struct nf_nat_range *range = (void *)cb->data; + + if (range->flags & NF_NAT_RANGE_PROTO_OFFSET) + xtables_error(PARAMETER_PROBLEM, + "Shifted portmap ranges not supported with this kernel"); + + __DNAT_fcheck(cb, &range->flags); +} + +static void DNAT_print6(const void *ip, const struct xt_entry_target *target, + int numeric) +{ + struct nf_nat_range2 range = {}; + + memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range)); + __DNAT_print(&range, true, AF_INET6); +} + +static void DNAT_save6(const void *ip, const struct xt_entry_target *target) +{ + struct nf_nat_range2 range = {}; + + memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range)); + __DNAT_print(&range, true, AF_INET6); +} + +static int DNAT_xlate6(struct xt_xlate *xl, + const struct xt_xlate_tg_params *params) +{ + struct nf_nat_range2 range = {}; + + memcpy(&range, (const void *)params->target->data, + sizeof(struct nf_nat_range)); + return __DNAT_xlate(xl, &range, AF_INET6); +} + +static void DNAT_parse6_v2(struct xt_option_call *cb) +{ + const struct ip6t_entry *entry = cb->xt_entry; + + __DNAT_parse(cb, entry->ipv6.proto, cb->data, AF_INET6); +} + +static void DNAT_print6_v2(const void *ip, const struct xt_entry_target *target, + int numeric) +{ + __DNAT_print((const void *)target->data, true, AF_INET6); +} + +static void DNAT_save6_v2(const void *ip, const struct xt_entry_target *target) { - return __DNAT_xlate(xl, (const void *)params->target->data); + __DNAT_print((const void *)target->data, true, AF_INET6); +} + +static int DNAT_xlate6_v2(struct xt_xlate *xl, + const struct xt_xlate_tg_params *params) +{ + return __DNAT_xlate(xl, (const void *)params->target->data, AF_INET6); } static struct xtables_target dnat_tg_reg[] = { @@ -347,6 +459,21 @@ static struct xtables_target dnat_tg_reg[] = { .x6_options = DNAT_opts, .xlate = DNAT_xlate, }, + { + .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, + .print = DNAT_print6, + .save = DNAT_save6, + .x6_parse = DNAT_parse6, + .x6_fcheck = DNAT_fcheck6, + .x6_options = DNAT_opts, + .xlate = DNAT_xlate6, + }, { .name = "DNAT", .version = XTABLES_VERSION, @@ -362,6 +489,21 @@ static struct xtables_target dnat_tg_reg[] = { .x6_options = DNAT_opts, .xlate = DNAT_xlate_v2, }, + { + .name = "DNAT", + .version = XTABLES_VERSION, + .family = NFPROTO_IPV6, + .revision = 2, + .size = XT_ALIGN(sizeof(struct nf_nat_range2)), + .userspacesize = XT_ALIGN(sizeof(struct nf_nat_range2)), + .help = DNAT_help_v2, + .print = DNAT_print6_v2, + .save = DNAT_save6_v2, + .x6_parse = DNAT_parse6_v2, + .x6_fcheck = DNAT_fcheck_v2, + .x6_options = DNAT_opts, + .xlate = DNAT_xlate6_v2, + }, }; void _init(void) -- cgit v1.2.3