--- /dev/null
+/*-
+ * Copyright (c) 2004 Andre Oppermann, Internet Business Solutions AG
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/sys/netinet/ipfw/ip_fw_pfil.c 200601 2009-12-16 10:48:40Z luigi $");
+
+#if !defined(KLD_MODULE)
+#include "opt_ipfw.h"
+#include "opt_ipdn.h"
+#include "opt_inet.h"
+#ifndef INET
+#error IPFIREWALL requires INET.
+#endif /* INET */
+#endif /* KLD_MODULE */
+#include "opt_inet6.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/module.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/rwlock.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/route.h>
+#include <net/pfil.h>
+#include <net/vnet.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/ip_var.h>
+#include <netinet/ip_fw.h>
+#include <netinet/ipfw/ip_fw_private.h>
+#include <netinet/ip_dummynet.h>
+#include <netgraph/ng_ipfw.h>
+
+#include <machine/in_cksum.h>
+
+static VNET_DEFINE(int, fw_enable) = 1;
+#define V_fw_enable VNET(fw_enable)
+
+#ifdef INET6
+static VNET_DEFINE(int, fw6_enable) = 1;
+#define V_fw6_enable VNET(fw6_enable)
+#endif
+
+int ipfw_chg_hook(SYSCTL_HANDLER_ARGS);
+
+/* Divert hooks. */
+void (*ip_divert_ptr)(struct mbuf *m, int incoming);
+
+/* ng_ipfw hooks. */
+ng_ipfw_input_t *ng_ipfw_input_p = NULL;
+
+/* Forward declarations. */
+static int ipfw_divert(struct mbuf **, int, struct ipfw_rule_ref *, int);
+
+#ifdef SYSCTL_NODE
+SYSCTL_DECL(_net_inet_ip_fw);
+SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, enable,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_enable), 0,
+ ipfw_chg_hook, "I", "Enable ipfw");
+#ifdef INET6
+SYSCTL_DECL(_net_inet6_ip6_fw);
+SYSCTL_VNET_PROC(_net_inet6_ip6_fw, OID_AUTO, enable,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw6_enable), 0,
+ ipfw_chg_hook, "I", "Enable ipfw+6");
+#endif /* INET6 */
+#endif /* SYSCTL_NODE */
+
+/*
+ * The pfilter hook to pass packets to ipfw_chk and then to
+ * dummynet, divert, netgraph or other modules.
+ * The packet may be consumed.
+ */
+int
+ipfw_check_hook(void *arg, struct mbuf **m0, struct ifnet *ifp, int dir,
+ struct inpcb *inp)
+{
+ struct ip_fw_args args;
+ struct m_tag *tag;
+ int ipfw;
+ int ret;
+
+ /* all the processing now uses ip_len in net format */
+ SET_NET_IPLEN(mtod(*m0, struct ip *));
+
+ /* convert dir to IPFW values */
+ dir = (dir == PFIL_IN) ? DIR_IN : DIR_OUT;
+ bzero(&args, sizeof(args));
+
+again:
+ /*
+ * extract and remove the tag if present. If we are left
+ * with onepass, optimize the outgoing path.
+ */
+ tag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL);
+ if (tag != NULL) {
+ args.rule = *((struct ipfw_rule_ref *)(tag+1));
+ m_tag_delete(*m0, tag);
+ if (args.rule.info & IPFW_ONEPASS) {
+ SET_HOST_IPLEN(mtod(*m0, struct ip *));
+ return 0;
+ }
+ }
+
+ args.m = *m0;
+ args.oif = dir == DIR_OUT ? ifp : NULL;
+ args.inp = inp;
+
+ ipfw = ipfw_chk(&args);
+ *m0 = args.m;
+
+ KASSERT(*m0 != NULL || ipfw == IP_FW_DENY, ("%s: m0 is NULL",
+ __func__));
+
+ /* breaking out of the switch means drop */
+ ret = 0; /* default return value for pass */
+ switch (ipfw) {
+ case IP_FW_PASS:
+ /* next_hop may be set by ipfw_chk */
+ if (args.next_hop == NULL)
+ break; /* pass */
+#ifndef IPFIREWALL_FORWARD
+ ret = EACCES;
+#else
+ {
+ struct m_tag *fwd_tag;
+
+ /* Incoming packets should not be tagged so we do not
+ * m_tag_find. Outgoing packets may be tagged, so we
+ * reuse the tag if present.
+ */
+ fwd_tag = (dir == DIR_IN) ? NULL :
+ m_tag_find(*m0, PACKET_TAG_IPFORWARD, NULL);
+ if (fwd_tag != NULL) {
+ m_tag_unlink(*m0, fwd_tag);
+ } else {
+ fwd_tag = m_tag_get(PACKET_TAG_IPFORWARD,
+ sizeof(struct sockaddr_in), M_NOWAIT);
+ if (fwd_tag == NULL) {
+ ret = EACCES;
+ break; /* i.e. drop */
+ }
+ }
+ bcopy(args.next_hop, (fwd_tag+1), sizeof(struct sockaddr_in));
+ m_tag_prepend(*m0, fwd_tag);
+
+ if (in_localip(args.next_hop->sin_addr))
+ (*m0)->m_flags |= M_FASTFWD_OURS;
+ }
+#endif
+ break;
+
+ case IP_FW_DENY:
+ ret = EACCES;
+ break; /* i.e. drop */
+
+ case IP_FW_DUMMYNET:
+ ret = EACCES;
+ if (ip_dn_io_ptr == NULL)
+ break; /* i.e. drop */
+ if (mtod(*m0, struct ip *)->ip_v == 4)
+ ret = ip_dn_io_ptr(m0, dir, &args);
+ else if (mtod(*m0, struct ip *)->ip_v == 6)
+ ret = ip_dn_io_ptr(m0, dir | PROTO_IPV6, &args);
+ else
+ break; /* drop it */
+ /*
+ * XXX should read the return value.
+ * dummynet normally eats the packet and sets *m0=NULL
+ * unless the packet can be sent immediately. In this
+ * case args is updated and we should re-run the
+ * check without clearing args.
+ */
+ if (*m0 != NULL)
+ goto again;
+ break;
+
+ case IP_FW_TEE:
+ case IP_FW_DIVERT:
+ if (ip_divert_ptr == NULL) {
+ ret = EACCES;
+ break; /* i.e. drop */
+ }
+ ret = ipfw_divert(m0, dir, &args.rule,
+ (ipfw == IP_FW_TEE) ? 1 : 0);
+ /* continue processing for the original packet (tee). */
+ if (*m0)
+ goto again;
+ break;
+
+ case IP_FW_NGTEE:
+ case IP_FW_NETGRAPH:
+ if (!NG_IPFW_LOADED) {
+ ret = EACCES;
+ break; /* i.e. drop */
+ }
+ ret = ng_ipfw_input_p(m0, dir, &args,
+ (ipfw == IP_FW_NGTEE) ? 1 : 0);
+ if (ipfw == IP_FW_NGTEE) /* ignore errors for NGTEE */
+ goto again; /* continue with packet */
+ break;
+
+ case IP_FW_NAT:
+ case IP_FW_REASS:
+ goto again; /* continue with packet */
+
+ default:
+ KASSERT(0, ("%s: unknown retval", __func__));
+ }
+
+ if (ret != 0) {
+ if (*m0)
+ FREE_PKT(*m0);
+ *m0 = NULL;
+ }
+ if (*m0)
+ SET_HOST_IPLEN(mtod(*m0, struct ip *));
+ return ret;
+}
+
+/* do the divert, return 1 on error 0 on success */
+static int
+ipfw_divert(struct mbuf **m0, int incoming, struct ipfw_rule_ref *rule,
+ int tee)
+{
+ /*
+ * ipfw_chk() has already tagged the packet with the divert tag.
+ * If tee is set, copy packet and return original.
+ * If not tee, consume packet and send it to divert socket.
+ */
+ struct mbuf *clone;
+ struct ip *ip;
+ struct m_tag *tag;
+
+ /* Cloning needed for tee? */
+ if (tee == 0) {
+ clone = *m0; /* use the original mbuf */
+ *m0 = NULL;
+ } else {
+ clone = m_dup(*m0, M_DONTWAIT);
+ /* If we cannot duplicate the mbuf, we sacrifice the divert
+ * chain and continue with the tee-ed packet.
+ */
+ if (clone == NULL)
+ return 1;
+ }
+
+ /*
+ * Divert listeners can normally handle non-fragmented packets,
+ * but we can only reass in the non-tee case.
+ * This means that listeners on a tee rule may get fragments,
+ * and have to live with that.
+ * Note that we now have the 'reass' ipfw option so if we care
+ * we can do it before a 'tee'.
+ */
+ ip = mtod(clone, struct ip *);
+ if (!tee && ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) {
+ int hlen;
+ struct mbuf *reass;
+
+ SET_HOST_IPLEN(ip); /* ip_reass wants host order */
+ reass = ip_reass(clone); /* Reassemble packet. */
+ if (reass == NULL)
+ return 0; /* not an error */
+ /* if reass = NULL then it was consumed by ip_reass */
+ /*
+ * IP header checksum fixup after reassembly and leave header
+ * in network byte order.
+ */
+ ip = mtod(reass, struct ip *);
+ hlen = ip->ip_hl << 2;
+ SET_NET_IPLEN(ip);
+ ip->ip_sum = 0;
+ if (hlen == sizeof(struct ip))
+ ip->ip_sum = in_cksum_hdr(ip);
+ else
+ ip->ip_sum = in_cksum(reass, hlen);
+ clone = reass;
+ }
+ /* attach a tag to the packet with the reinject info */
+ tag = m_tag_alloc(MTAG_IPFW_RULE, 0,
+ sizeof(struct ipfw_rule_ref), M_NOWAIT);
+ if (tag == NULL) {
+ FREE_PKT(clone);
+ return 1;
+ }
+ *((struct ipfw_rule_ref *)(tag+1)) = *rule;
+ m_tag_prepend(clone, tag);
+
+ /* Do the dirty job... */
+ ip_divert_ptr(clone, incoming);
+ return 0;
+}
+
+/*
+ * attach or detach hooks for a given protocol family
+ */
+static int
+ipfw_hook(int onoff, int pf)
+{
+ struct pfil_head *pfh;
+
+ pfh = pfil_head_get(PFIL_TYPE_AF, pf);
+ if (pfh == NULL)
+ return ENOENT;
+
+ (void) (onoff ? pfil_add_hook : pfil_remove_hook)
+ (ipfw_check_hook, NULL, PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh);
+
+ return 0;
+}
+
+int
+ipfw_attach_hooks(int arg)
+{
+ int error = 0;
+
+ if (arg == 0) /* detach */
+ ipfw_hook(0, AF_INET);
+ else if (V_fw_enable && ipfw_hook(1, AF_INET) != 0) {
+ error = ENOENT; /* see ip_fw_pfil.c::ipfw_hook() */
+ printf("ipfw_hook() error\n");
+ }
+#ifdef INET6
+ if (arg == 0) /* detach */
+ ipfw_hook(0, AF_INET6);
+ else if (V_fw6_enable && ipfw_hook(1, AF_INET6) != 0) {
+ error = ENOENT;
+ printf("ipfw6_hook() error\n");
+ }
+#endif
+ return error;
+}
+
+int
+ipfw_chg_hook(SYSCTL_HANDLER_ARGS)
+{
+ int enable;
+ int oldenable;
+ int error;
+ int af;
+
+ if (arg1 == &VNET_NAME(fw_enable)) {
+ enable = V_fw_enable;
+ af = AF_INET;
+ }
+#ifdef INET6
+ else if (arg1 == &VNET_NAME(fw6_enable)) {
+ enable = V_fw6_enable;
+ af = AF_INET6;
+ }
+#endif
+ else
+ return (EINVAL);
+
+ oldenable = enable;
+
+ error = sysctl_handle_int(oidp, &enable, 0, req);
+
+ if (error)
+ return (error);
+
+ enable = (enable) ? 1 : 0;
+
+ if (enable == oldenable)
+ return (0);
+
+ error = ipfw_hook(enable, af);
+ if (error)
+ return (error);
+ if (af == AF_INET)
+ V_fw_enable = enable;
+#ifdef INET6
+ else if (af == AF_INET6)
+ V_fw6_enable = enable;
+#endif
+
+ return (0);
+}
+/* end of file */
git://git.onelab.eu / ipfw.git / blobdiff