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-rw-r--r--src/libfirewall/firewall-util.c359
1 files changed, 359 insertions, 0 deletions
diff --git a/src/libfirewall/firewall-util.c b/src/libfirewall/firewall-util.c
new file mode 100644
index 0000000000..009cef3e88
--- /dev/null
+++ b/src/libfirewall/firewall-util.c
@@ -0,0 +1,359 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2015 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#warning "Temporary work-around for broken glibc vs. linux kernel header definitions"
+#warning "This really should be removed sooner rather than later, when this is fixed upstream"
+#define _NET_IF_H 1
+
+#include <alloca.h>
+#include <arpa/inet.h>
+#include <endian.h>
+#include <errno.h>
+#include <net/if.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/socket.h>
+#ifndef IFNAMSIZ
+#define IFNAMSIZ 16
+#endif
+#include <libiptc/libiptc.h>
+
+#include <linux/if.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter/nf_nat.h>
+#include <linux/netfilter/xt_addrtype.h>
+
+#include "basic/alloc-util.h"
+#include "basic/in-addr-util.h"
+#include "basic/macro.h"
+#include "basic/socket-util.h"
+
+#include "firewall-util.h"
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct xtc_handle*, iptc_free);
+
+static int entry_fill_basics(
+ struct ipt_entry *entry,
+ int protocol,
+ const char *in_interface,
+ const union in_addr_union *source,
+ unsigned source_prefixlen,
+ const char *out_interface,
+ const union in_addr_union *destination,
+ unsigned destination_prefixlen) {
+
+ assert(entry);
+
+ if (out_interface && !ifname_valid(out_interface))
+ return -EINVAL;
+ if (in_interface && !ifname_valid(in_interface))
+ return -EINVAL;
+
+ entry->ip.proto = protocol;
+
+ if (in_interface) {
+ strcpy(entry->ip.iniface, in_interface);
+ memset(entry->ip.iniface_mask, 0xFF, strlen(in_interface)+1);
+ }
+ if (source) {
+ entry->ip.src = source->in;
+ in_addr_prefixlen_to_netmask(&entry->ip.smsk, source_prefixlen);
+ }
+
+ if (out_interface) {
+ strcpy(entry->ip.outiface, out_interface);
+ memset(entry->ip.outiface_mask, 0xFF, strlen(out_interface)+1);
+ }
+ if (destination) {
+ entry->ip.dst = destination->in;
+ in_addr_prefixlen_to_netmask(&entry->ip.dmsk, destination_prefixlen);
+ }
+
+ return 0;
+}
+
+int fw_add_masquerade(
+ bool add,
+ int af,
+ int protocol,
+ const union in_addr_union *source,
+ unsigned source_prefixlen,
+ const char *out_interface,
+ const union in_addr_union *destination,
+ unsigned destination_prefixlen) {
+
+ _cleanup_(iptc_freep) struct xtc_handle *h = NULL;
+ struct ipt_entry *entry, *mask;
+ struct ipt_entry_target *t;
+ size_t sz;
+ struct nf_nat_ipv4_multi_range_compat *mr;
+ int r;
+
+ if (af != AF_INET)
+ return -EOPNOTSUPP;
+
+ if (protocol != 0 && protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
+ return -EOPNOTSUPP;
+
+ h = iptc_init("nat");
+ if (!h)
+ return -errno;
+
+ sz = XT_ALIGN(sizeof(struct ipt_entry)) +
+ XT_ALIGN(sizeof(struct ipt_entry_target)) +
+ XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+
+ /* Put together the entry we want to add or remove */
+ entry = alloca0(sz);
+ entry->next_offset = sz;
+ entry->target_offset = XT_ALIGN(sizeof(struct ipt_entry));
+ r = entry_fill_basics(entry, protocol, NULL, source, source_prefixlen, out_interface, destination, destination_prefixlen);
+ if (r < 0)
+ return r;
+
+ /* Fill in target part */
+ t = ipt_get_target(entry);
+ t->u.target_size =
+ XT_ALIGN(sizeof(struct ipt_entry_target)) +
+ XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+ strncpy(t->u.user.name, "MASQUERADE", sizeof(t->u.user.name));
+ mr = (struct nf_nat_ipv4_multi_range_compat*) t->data;
+ mr->rangesize = 1;
+
+ /* Create a search mask entry */
+ mask = alloca(sz);
+ memset(mask, 0xFF, sz);
+
+ if (add) {
+ if (iptc_check_entry("POSTROUTING", entry, (unsigned char*) mask, h))
+ return 0;
+ if (errno != ENOENT) /* if other error than not existing yet, fail */
+ return -errno;
+
+ if (!iptc_insert_entry("POSTROUTING", entry, 0, h))
+ return -errno;
+ } else {
+ if (!iptc_delete_entry("POSTROUTING", entry, (unsigned char*) mask, h)) {
+ if (errno == ENOENT) /* if it's already gone, all is good! */
+ return 0;
+
+ return -errno;
+ }
+ }
+
+ if (!iptc_commit(h))
+ return -errno;
+
+ return 0;
+}
+
+int fw_add_local_dnat(
+ bool add,
+ int af,
+ int protocol,
+ const char *in_interface,
+ const union in_addr_union *source,
+ unsigned source_prefixlen,
+ const union in_addr_union *destination,
+ unsigned destination_prefixlen,
+ uint16_t local_port,
+ const union in_addr_union *remote,
+ uint16_t remote_port,
+ const union in_addr_union *previous_remote) {
+
+
+ _cleanup_(iptc_freep) struct xtc_handle *h = NULL;
+ struct ipt_entry *entry, *mask;
+ struct ipt_entry_target *t;
+ struct ipt_entry_match *m;
+ struct xt_addrtype_info_v1 *at;
+ struct nf_nat_ipv4_multi_range_compat *mr;
+ size_t sz, msz;
+ int r;
+
+ assert(add || !previous_remote);
+
+ if (af != AF_INET)
+ return -EOPNOTSUPP;
+
+ if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
+ return -EOPNOTSUPP;
+
+ if (local_port <= 0)
+ return -EINVAL;
+
+ if (remote_port <= 0)
+ return -EINVAL;
+
+ h = iptc_init("nat");
+ if (!h)
+ return -errno;
+
+ sz = XT_ALIGN(sizeof(struct ipt_entry)) +
+ XT_ALIGN(sizeof(struct ipt_entry_match)) +
+ XT_ALIGN(sizeof(struct xt_addrtype_info_v1)) +
+ XT_ALIGN(sizeof(struct ipt_entry_target)) +
+ XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+
+ if (protocol == IPPROTO_TCP)
+ msz = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+ XT_ALIGN(sizeof(struct xt_tcp));
+ else
+ msz = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+ XT_ALIGN(sizeof(struct xt_udp));
+
+ sz += msz;
+
+ /* Fill in basic part */
+ entry = alloca0(sz);
+ entry->next_offset = sz;
+ entry->target_offset =
+ XT_ALIGN(sizeof(struct ipt_entry)) +
+ XT_ALIGN(sizeof(struct ipt_entry_match)) +
+ XT_ALIGN(sizeof(struct xt_addrtype_info_v1)) +
+ msz;
+ r = entry_fill_basics(entry, protocol, in_interface, source, source_prefixlen, NULL, destination, destination_prefixlen);
+ if (r < 0)
+ return r;
+
+ /* Fill in first match */
+ m = (struct ipt_entry_match*) ((uint8_t*) entry + XT_ALIGN(sizeof(struct ipt_entry)));
+ m->u.match_size = msz;
+ if (protocol == IPPROTO_TCP) {
+ struct xt_tcp *tcp;
+
+ strncpy(m->u.user.name, "tcp", sizeof(m->u.user.name));
+ tcp = (struct xt_tcp*) m->data;
+ tcp->dpts[0] = tcp->dpts[1] = local_port;
+ tcp->spts[0] = 0;
+ tcp->spts[1] = 0xFFFF;
+
+ } else {
+ struct xt_udp *udp;
+
+ strncpy(m->u.user.name, "udp", sizeof(m->u.user.name));
+ udp = (struct xt_udp*) m->data;
+ udp->dpts[0] = udp->dpts[1] = local_port;
+ udp->spts[0] = 0;
+ udp->spts[1] = 0xFFFF;
+ }
+
+ /* Fill in second match */
+ m = (struct ipt_entry_match*) ((uint8_t*) entry + XT_ALIGN(sizeof(struct ipt_entry)) + msz);
+ m->u.match_size =
+ XT_ALIGN(sizeof(struct ipt_entry_match)) +
+ XT_ALIGN(sizeof(struct xt_addrtype_info_v1));
+ strncpy(m->u.user.name, "addrtype", sizeof(m->u.user.name));
+ m->u.user.revision = 1;
+ at = (struct xt_addrtype_info_v1*) m->data;
+ at->dest = XT_ADDRTYPE_LOCAL;
+
+ /* Fill in target part */
+ t = ipt_get_target(entry);
+ t->u.target_size =
+ XT_ALIGN(sizeof(struct ipt_entry_target)) +
+ XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+ strncpy(t->u.user.name, "DNAT", sizeof(t->u.user.name));
+ mr = (struct nf_nat_ipv4_multi_range_compat*) t->data;
+ mr->rangesize = 1;
+ mr->range[0].flags = NF_NAT_RANGE_PROTO_SPECIFIED|NF_NAT_RANGE_MAP_IPS;
+ mr->range[0].min_ip = mr->range[0].max_ip = remote->in.s_addr;
+ if (protocol == IPPROTO_TCP)
+ mr->range[0].min.tcp.port = mr->range[0].max.tcp.port = htons(remote_port);
+ else
+ mr->range[0].min.udp.port = mr->range[0].max.udp.port = htons(remote_port);
+
+ mask = alloca0(sz);
+ memset(mask, 0xFF, sz);
+
+ if (add) {
+ /* Add the PREROUTING rule, if it is missing so far */
+ if (!iptc_check_entry("PREROUTING", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -EINVAL;
+
+ if (!iptc_insert_entry("PREROUTING", entry, 0, h))
+ return -errno;
+ }
+
+ /* If a previous remote is set, remove its entry */
+ if (previous_remote && previous_remote->in.s_addr != remote->in.s_addr) {
+ mr->range[0].min_ip = mr->range[0].max_ip = previous_remote->in.s_addr;
+
+ if (!iptc_delete_entry("PREROUTING", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -errno;
+ }
+
+ mr->range[0].min_ip = mr->range[0].max_ip = remote->in.s_addr;
+ }
+
+ /* Add the OUTPUT rule, if it is missing so far */
+ if (!in_interface) {
+
+ /* Don't apply onto loopback addresses */
+ if (!destination) {
+ entry->ip.dst.s_addr = htobe32(0x7F000000);
+ entry->ip.dmsk.s_addr = htobe32(0xFF000000);
+ entry->ip.invflags = IPT_INV_DSTIP;
+ }
+
+ if (!iptc_check_entry("OUTPUT", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -errno;
+
+ if (!iptc_insert_entry("OUTPUT", entry, 0, h))
+ return -errno;
+ }
+
+ /* If a previous remote is set, remove its entry */
+ if (previous_remote && previous_remote->in.s_addr != remote->in.s_addr) {
+ mr->range[0].min_ip = mr->range[0].max_ip = previous_remote->in.s_addr;
+
+ if (!iptc_delete_entry("OUTPUT", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -errno;
+ }
+ }
+ }
+ } else {
+ if (!iptc_delete_entry("PREROUTING", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -errno;
+ }
+
+ if (!in_interface) {
+ if (!destination) {
+ entry->ip.dst.s_addr = htobe32(0x7F000000);
+ entry->ip.dmsk.s_addr = htobe32(0xFF000000);
+ entry->ip.invflags = IPT_INV_DSTIP;
+ }
+
+ if (!iptc_delete_entry("OUTPUT", entry, (unsigned char*) mask, h)) {
+ if (errno != ENOENT)
+ return -errno;
+ }
+ }
+ }
+
+ if (!iptc_commit(h))
+ return -errno;
+
+ return 0;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-18 07:08:38 +0000