/* * firewall3 - 3rd OpenWrt UCI firewall implementation * * Copyright (C) 2014 Jo-Philipp Wich * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "snats.h" const struct fw3_option fw3_snat_opts[] = { FW3_OPT("enabled", bool, snat, enabled), FW3_OPT("name", string, snat, name), FW3_OPT("family", family, snat, family), FW3_OPT("src", device, snat, src), FW3_OPT("device", string, snat, device), FW3_OPT("ipset", setmatch, snat, ipset), FW3_LIST("proto", protocol, snat, proto), FW3_OPT("src_ip", network, snat, ip_src), FW3_OPT("src_port", port, snat, port_src), FW3_OPT("snat_ip", network, snat, ip_snat), FW3_OPT("snat_port", port, snat, port_snat), FW3_OPT("dest_ip", network, snat, ip_dest), FW3_OPT("dest_port", port, snat, port_dest), FW3_OPT("extra", string, snat, extra), FW3_OPT("limit", limit, snat, limit), FW3_OPT("limit_burst", int, snat, limit.burst), FW3_OPT("connlimit_ports", bool, snat, connlimit_ports), FW3_OPT("utc_time", bool, snat, time.utc), FW3_OPT("start_date", date, snat, time.datestart), FW3_OPT("stop_date", date, snat, time.datestop), FW3_OPT("start_time", time, snat, time.timestart), FW3_OPT("stop_time", time, snat, time.timestop), FW3_OPT("weekdays", weekdays, snat, time.weekdays), FW3_OPT("monthdays", monthdays, snat, time.monthdays), FW3_OPT("mark", mark, snat, mark), FW3_OPT("target", target, snat, target), { } }; static bool check_families(struct uci_element *e, struct fw3_snat *r) { if (r->family == FW3_FAMILY_ANY) return true; if (r->_src && r->_src->family && r->_src->family != r->family) { warn_section("nat", r, e, "refers to source zone with different family"); return false; } if (r->ipset.ptr && r->ipset.ptr->family && r->ipset.ptr->family != r->family) { warn_section("nat", r, e, "refers to ipset with different family"); return false; } if (r->ip_src.family && r->ip_src.family != r->family) { warn_section("nat", r, e, "uses source ip with different family"); return false; } if (r->ip_dest.family && r->ip_dest.family != r->family) { warn_section("nat", r, e, "uses destination ip with different family"); return false; } if (r->ip_snat.family && r->ip_snat.family != r->family) { warn_section("nat", r, e, "uses snat ip with different family"); return false; } return true; } static struct fw3_snat* alloc_snat(struct fw3_state *state) { struct fw3_snat *snat = calloc(1, sizeof(*snat)); if (snat) { INIT_LIST_HEAD(&snat->proto); list_add_tail(&snat->list, &state->snats); snat->enabled = true; } return snat; } static bool check_snat(struct fw3_state *state, struct fw3_snat *snat, struct uci_element *e) { if (!snat->enabled) return false; if (snat->src.invert) { warn_section("nat", snat, e, "must not have an inverted source"); return false; } else if (snat->src.set && !snat->src.any && !(snat->_src = fw3_lookup_zone(state, snat->src.name))) { warn_section("nat", snat, e, "refers to not existing zone '%s'", snat->src.name); return false; } else if (snat->ipset.set && state->disable_ipsets) { warn_section("nat", snat, e, "skipped due to disabled ipset support"); return false; } else if (snat->ipset.set && !(snat->ipset.ptr = fw3_lookup_ipset(state, snat->ipset.name))) { warn_section("nat", snat, e, "refers to unknown ipset '%s'", snat->ipset.name); return false; } if (!check_families(e, snat)) return false; if (snat->target == FW3_FLAG_UNSPEC) { warn_section("nat", snat, e, "has no target specified, defaulting to MASQUERADE"); snat->target = FW3_FLAG_MASQUERADE; } else if (snat->target != FW3_FLAG_ACCEPT && snat->target != FW3_FLAG_SNAT && snat->target != FW3_FLAG_MASQUERADE) { warn_section("nat", snat, e, "has invalid target specified, defaulting to MASQUERADE"); snat->target = FW3_FLAG_MASQUERADE; } if (snat->target == FW3_FLAG_SNAT && !snat->ip_snat.set && !snat->port_snat.set) { warn_section("nat", snat, e, "needs either 'snat_ip' or 'snat_port' for SNAT"); return false; } else if (snat->target != FW3_FLAG_SNAT && snat->ip_snat.set) { warn_section("nat", snat, e, "must not use 'snat_ip' for non-SNAT"); return false; } else if (snat->target != FW3_FLAG_SNAT && snat->port_snat.set) { warn_section("nat", snat, e, "must not use 'snat_port' for non-SNAT"); return false; } if (list_empty(&snat->proto)) { warn_section("nat", snat, e, "does not specify a protocol, assuming all"); fw3_parse_protocol(&snat->proto, "all", true); } if (snat->_src) set(snat->_src->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT); return true; } void fw3_load_snats(struct fw3_state *state, struct uci_package *p, struct blob_attr *a) { struct uci_section *s; struct uci_element *e; struct fw3_snat *snat; struct blob_attr *entry; unsigned rem; INIT_LIST_HEAD(&state->snats); blob_for_each_attr(entry, a, rem) { const char *type = NULL; const char *name = "ubus rule"; if (!fw3_attr_parse_name_type(entry, &name, &type)) continue; if (strcmp(type, "nat")) continue; snat = alloc_snat(state); if (!snat) continue; if (!fw3_parse_blob_options(snat, fw3_snat_opts, entry, name)) { warn_section("nat", snat, NULL, "skipped due to invalid options"); fw3_free_snat(snat); continue; } if (!check_snat(state, snat, NULL)) fw3_free_snat(snat); } uci_foreach_element(&p->sections, e) { s = uci_to_section(e); if (strcmp(s->type, "nat")) continue; snat = alloc_snat(state); if (!snat) continue; if (!fw3_parse_options(snat, fw3_snat_opts, s)) { warn_elem(e, "skipped due to invalid options"); fw3_free_snat(snat); continue; } if (!check_snat(state, snat, e)) fw3_free_snat(snat); } } static void append_chain(struct fw3_ipt_rule *r, struct fw3_snat *snat) { if (snat->_src) fw3_ipt_rule_append(r, "zone_%s_postrouting", snat->src.name); else fw3_ipt_rule_append(r, "POSTROUTING"); } static void set_target(struct fw3_ipt_rule *r, struct fw3_snat *snat, struct fw3_protocol *proto) { char buf[sizeof("255.255.255.255:65535-65535\0")]; if (snat->target == FW3_FLAG_SNAT) { buf[0] = '\0'; if (snat->ip_snat.set) { inet_ntop(AF_INET, &snat->ip_snat.address.v4, buf, sizeof(buf)); } if (snat->port_snat.set && proto && !proto->any && (proto->protocol == 6 || proto->protocol == 17 || proto->protocol == 1)) { if (snat->port_snat.port_min == snat->port_snat.port_max) sprintf(buf + strlen(buf), ":%u", snat->port_snat.port_min); else sprintf(buf + strlen(buf), ":%u-%u", snat->port_snat.port_min, snat->port_snat.port_max); if (snat->connlimit_ports) { char portcntbuf[6]; snprintf(portcntbuf, sizeof(portcntbuf), "%u", 1 + snat->port_snat.port_max - snat->port_snat.port_min); fw3_ipt_rule_addarg(r, false, "-m", "connlimit"); fw3_ipt_rule_addarg(r, false, "--connlimit-daddr", NULL); fw3_ipt_rule_addarg(r, false, "--connlimit-upto", portcntbuf); } } fw3_ipt_rule_target(r, "SNAT"); fw3_ipt_rule_addarg(r, false, "--to-source", buf); } else if (snat->target == FW3_FLAG_ACCEPT) { fw3_ipt_rule_target(r, "ACCEPT"); } else { fw3_ipt_rule_target(r, "MASQUERADE"); } } static void set_comment(struct fw3_ipt_rule *r, const char *name, int num) { if (name) fw3_ipt_rule_comment(r, name); else fw3_ipt_rule_comment(r, "@nat[%u]", num); } static void print_snat(struct fw3_ipt_handle *h, struct fw3_state *state, struct fw3_snat *snat, int num, struct fw3_protocol *proto) { struct fw3_ipt_rule *r; struct fw3_address *src, *dst; struct fw3_port *spt, *dpt; switch (h->table) { case FW3_TABLE_NAT: src = &snat->ip_src; dst = &snat->ip_dest; spt = &snat->port_src; dpt = &snat->port_dest; r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst); fw3_ipt_rule_sport_dport(r, spt, dpt); fw3_ipt_rule_device(r, snat->device, true); fw3_ipt_rule_ipset(r, &snat->ipset); fw3_ipt_rule_limit(r, &snat->limit); fw3_ipt_rule_time(r, &snat->time); fw3_ipt_rule_mark(r, &snat->mark); set_target(r, snat, proto); fw3_ipt_rule_extra(r, snat->extra); set_comment(r, snat->name, num); append_chain(r, snat); break; default: break; } } static void expand_snat(struct fw3_ipt_handle *handle, struct fw3_state *state, struct fw3_snat *snat, int num) { struct fw3_protocol *proto; if (snat->name) info(" * NAT '%s'", snat->name); else info(" * NAT #%u", num); if (!fw3_is_family(snat->_src, handle->family)) { info(" ! Skipping due to different family of zone"); return; } if (!fw3_is_family(&snat->ip_src, handle->family) || !fw3_is_family(&snat->ip_dest, handle->family) || !fw3_is_family(&snat->ip_snat, handle->family)) { if (!snat->ip_src.resolved || !snat->ip_dest.resolved || !snat->ip_snat.resolved) info(" ! Skipping due to different family of ip address"); return; } if (snat->ipset.ptr) { if (!fw3_is_family(snat->ipset.ptr, handle->family)) { info(" ! Skipping due to different family in ipset"); return; } if (!fw3_check_ipset(snat->ipset.ptr)) { info(" ! Skipping due to missing ipset '%s'", snat->ipset.ptr->external ? snat->ipset.ptr->external : snat->ipset.ptr->name); return; } set(snat->ipset.ptr->flags, handle->family, handle->family); } fw3_foreach(proto, &snat->proto) print_snat(handle, state, snat, num, proto); } void fw3_print_snats(struct fw3_ipt_handle *handle, struct fw3_state *state) { int num = 0; struct fw3_snat *snat; if (handle->family == FW3_FAMILY_V6) return; if (handle->table != FW3_TABLE_NAT) return; list_for_each_entry(snat, &state->snats, list) expand_snat(handle, state, snat, num++); }