ip_fw.h
/*-
* Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
*
* 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.
*
* $FreeBSD$
*/
#ifndef _IPFW2_H
#define _IPFW2_H
/*
* The default rule number. By the design of ip_fw, the default rule
* is the last one, so its number can also serve as the highest number
* allowed for a rule. The ip_fw code relies on both meanings of this
* constant.
*/
#define IPFW_DEFAULT_RULE 65535
/*
* The kernel representation of ipfw rules is made of a list of
* 'instructions' (for all practical purposes equivalent to BPF
* instructions), which specify which fields of the packet
* (or its metadata) should be analysed.
*
* Each instruction is stored in a structure which begins with
* "ipfw_insn", and can contain extra fields depending on the
* instruction type (listed below).
* Note that the code is written so that individual instructions
* have a size which is a multiple of 32 bits. This means that, if
* such structures contain pointers or other 64-bit entities,
* (there is just one instance now) they may end up unaligned on
* 64-bit architectures, so the must be handled with care.
*
* "enum ipfw_opcodes" are the opcodes supported. We can have up
* to 256 different opcodes. When adding new opcodes, they should
* be appended to the end of the opcode list before O_LAST_OPCODE,
* this will prevent the ABI from being broken, otherwise users
* will have to recompile ipfw(8) when they update the kernel.
*/
enum ipfw_opcodes { /* arguments (4 byte each) */
O_NOP,
O_IP_SRC, /* u32 = IP */
O_IP_SRC_MASK, /* ip = IP/mask */
O_IP_SRC_ME, /* none */
O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */
O_IP_DST, /* u32 = IP */
O_IP_DST_MASK, /* ip = IP/mask */
O_IP_DST_ME, /* none */
O_IP_DST_SET, /* u32=base, arg1=len, bitmap */
O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */
O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */
O_PROTO, /* arg1=protocol */
O_MACADDR2, /* 2 mac addr:mask */
O_MAC_TYPE, /* same as srcport */
O_LAYER2, /* none */
O_IN, /* none */
O_FRAG, /* none */
O_RECV, /* none */
O_XMIT, /* none */
O_VIA, /* none */
O_IPOPT, /* arg1 = 2*u8 bitmap */
O_IPLEN, /* arg1 = len */
O_IPID, /* arg1 = id */
O_IPTOS, /* arg1 = id */
O_IPPRECEDENCE, /* arg1 = precedence << 5 */
O_IPTTL, /* arg1 = TTL */
O_IPVER, /* arg1 = version */
O_UID, /* u32 = id */
O_GID, /* u32 = id */
O_ESTAB, /* none (tcp established) */
O_TCPFLAGS, /* arg1 = 2*u8 bitmap */
O_TCPWIN, /* arg1 = desired win */
O_TCPSEQ, /* u32 = desired seq. */
O_TCPACK, /* u32 = desired seq. */
O_ICMPTYPE, /* u32 = icmp bitmap */
O_TCPOPTS, /* arg1 = 2*u8 bitmap */
O_VERREVPATH, /* none */
O_VERSRCREACH, /* none */
O_PROBE_STATE, /* none */
O_KEEP_STATE, /* none */
O_LIMIT, /* ipfw_insn_limit */
O_LIMIT_PARENT, /* dyn_type, not an opcode. */
/*
* These are really 'actions'.
*/
O_LOG, /* ipfw_insn_log */
O_PROB, /* u32 = match probability */
O_CHECK_STATE, /* none */
O_ACCEPT, /* none */
O_DENY, /* none */
O_REJECT, /* arg1=icmp arg (same as deny) */
O_COUNT, /* none */
O_SKIPTO, /* arg1=next rule number */
O_PIPE, /* arg1=pipe number */
O_QUEUE, /* arg1=queue number */
O_DIVERT, /* arg1=port number */
O_TEE, /* arg1=port number */
O_FORWARD_IP, /* fwd sockaddr */
O_FORWARD_MAC, /* fwd mac */
O_NAT, /* nope */
/*
* More opcodes.
*/
O_IPSEC, /* has ipsec history */
O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */
O_IP_DST_LOOKUP, /* arg1=table number, u32=value */
O_ANTISPOOF, /* none */
O_JAIL, /* u32 = id */
O_ALTQ, /* u32 = altq classif. qid */
O_DIVERTED, /* arg1=bitmap (1:loop, 2:out) */
O_TCPDATALEN, /* arg1 = tcp data len */
O_IP6_SRC, /* address without mask */
O_IP6_SRC_ME, /* my addresses */
O_IP6_SRC_MASK, /* address with the mask */
O_IP6_DST,
O_IP6_DST_ME,
O_IP6_DST_MASK,
O_FLOW6ID, /* for flow id tag in the ipv6 pkt */
O_ICMP6TYPE, /* icmp6 packet type filtering */
O_EXT_HDR, /* filtering for ipv6 extension header */
O_IP6,
/*
* actions for ng_ipfw
*/
O_NETGRAPH, /* send to ng_ipfw */
O_NGTEE, /* copy to ng_ipfw */
O_IP4,
O_UNREACH6, /* arg1=icmpv6 code arg (deny) */
O_TAG, /* arg1=tag number */
O_TAGGED, /* arg1=tag number */
O_SETFIB, /* arg1=FIB number */
O_FIB, /* arg1=FIB desired fib number */
O_LAST_OPCODE /* not an opcode! */
};
/*
* The extension header are filtered only for presence using a bit
* vector with a flag for each header.
*/
#define EXT_FRAGMENT 0x1
#define EXT_HOPOPTS 0x2
#define EXT_ROUTING 0x4
#define EXT_AH 0x8
#define EXT_ESP 0x10
#define EXT_DSTOPTS 0x20
#define EXT_RTHDR0 0x40
#define EXT_RTHDR2 0x80
/*
* Template for instructions.
*
* ipfw_insn is used for all instructions which require no operands,
* a single 16-bit value (arg1), or a couple of 8-bit values.
*
* For other instructions which require different/larger arguments
* we have derived structures, ipfw_insn_*.
*
* The size of the instruction (in 32-bit words) is in the low
* 6 bits of "len". The 2 remaining bits are used to implement
* NOT and OR on individual instructions. Given a type, you can
* compute the length to be put in "len" using F_INSN_SIZE(t)
*
* F_NOT negates the match result of the instruction.
*
* F_OR is used to build or blocks. By default, instructions
* are evaluated as part of a logical AND. An "or" block
* { X or Y or Z } contains F_OR set in all but the last
* instruction of the block. A match will cause the code
* to skip past the last instruction of the block.
*
* NOTA BENE: in a couple of places we assume that
* sizeof(ipfw_insn) == sizeof(u_int32_t)
* this needs to be fixed.
*
*/
typedef struct _ipfw_insn { /* template for instructions */
u_int8_t opcode;
u_int8_t len; /* number of 32-bit words */
#define F_NOT 0x80
#define F_OR 0x40
#define F_LEN_MASK 0x3f
#define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
u_int16_t arg1;
} ipfw_insn;
/*
* The F_INSN_SIZE(type) computes the size, in 4-byte words, of
* a given type.
*/
#define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
#define MTAG_IPFW 1148380143 /* IPFW-tagged cookie */
/*
* This is used to store an array of 16-bit entries (ports etc.)
*/
typedef struct _ipfw_insn_u16 {
ipfw_insn o;
u_int16_t ports[2]; /* there may be more */
} ipfw_insn_u16;
/*
* This is used to store an array of 32-bit entries
* (uid, single IPv4 addresses etc.)
*/
typedef struct _ipfw_insn_u32 {
ipfw_insn o;
u_int32_t d[1]; /* one or more */
} ipfw_insn_u32;
/*
* This is used to store IP addr-mask pairs.
*/
typedef struct _ipfw_insn_ip {
ipfw_insn o;
struct in_addr addr;
struct in_addr mask;
} ipfw_insn_ip;
/*
* This is used to forward to a given address (ip).
*/
typedef struct _ipfw_insn_sa {
ipfw_insn o;
struct sockaddr_in sa;
} ipfw_insn_sa;
/*
* This is used for MAC addr-mask pairs.
*/
typedef struct _ipfw_insn_mac {
ipfw_insn o;
u_char addr[12]; /* dst[6] + src[6] */
u_char mask[12]; /* dst[6] + src[6] */
} ipfw_insn_mac;
/*
* This is used for interface match rules (recv xx, xmit xx).
*/
typedef struct _ipfw_insn_if {
ipfw_insn o;
union {
struct in_addr ip;
int glob;
} p;
char name[IFNAMSIZ];
} ipfw_insn_if;
/*
* This is used for storing an altq queue id number.
*/
typedef struct _ipfw_insn_altq {
ipfw_insn o;
u_int32_t qid;
} ipfw_insn_altq;
/*
* This is used for limit rules.
*/
typedef struct _ipfw_insn_limit {
ipfw_insn o;
u_int8_t _pad;
u_int8_t limit_mask; /* combination of DYN_* below */
#define DYN_SRC_ADDR 0x1
#define DYN_SRC_PORT 0x2
#define DYN_DST_ADDR 0x4
#define DYN_DST_PORT 0x8
u_int16_t conn_limit;
} ipfw_insn_limit;
/*
* This is used for log instructions.
*/
typedef struct _ipfw_insn_log {
ipfw_insn o;
u_int32_t max_log; /* how many do we log -- 0 = all */
u_int32_t log_left; /* how many left to log */
} ipfw_insn_log;
/*
* Data structures required by both ipfw(8) and ipfw(4) but not part of the
* management API are protected by IPFW_INTERNAL.
*/
#ifdef IPFW_INTERNAL
/* Server pool support (LSNAT). */
struct cfg_spool {
LIST_ENTRY(cfg_spool) _next; /* chain of spool instances */
struct in_addr addr;
u_short port;
};
#endif
/* Redirect modes id. */
#define REDIR_ADDR 0x01
#define REDIR_PORT 0x02
#define REDIR_PROTO 0x04
#ifdef IPFW_INTERNAL
/* Nat redirect configuration. */
struct cfg_redir {
LIST_ENTRY(cfg_redir) _next; /* chain of redir instances */
u_int16_t mode; /* type of redirect mode */
struct in_addr laddr; /* local ip address */
struct in_addr paddr; /* public ip address */
struct in_addr raddr; /* remote ip address */
u_short lport; /* local port */
u_short pport; /* public port */
u_short rport; /* remote port */
u_short pport_cnt; /* number of public ports */
u_short rport_cnt; /* number of remote ports */
int proto; /* protocol: tcp/udp */
struct alias_link **alink;
/* num of entry in spool chain */
u_int16_t spool_cnt;
/* chain of spool instances */
LIST_HEAD(spool_chain, cfg_spool) spool_chain;
};
#endif
#define NAT_BUF_LEN 1024
#ifdef IPFW_INTERNAL
/* Nat configuration data struct. */
struct cfg_nat {
/* chain of nat instances */
LIST_ENTRY(cfg_nat) _next;
int id; /* nat id */
struct in_addr ip; /* nat ip address */
char if_name[IF_NAMESIZE]; /* interface name */
int mode; /* aliasing mode */
struct libalias *lib; /* libalias instance */
/* number of entry in spool chain */
int redir_cnt;
/* chain of redir instances */
LIST_HEAD(redir_chain, cfg_redir) redir_chain;
};
#endif
#define SOF_NAT sizeof(struct cfg_nat)
#define SOF_REDIR sizeof(struct cfg_redir)
#define SOF_SPOOL sizeof(struct cfg_spool)
/* Nat command. */
typedef struct _ipfw_insn_nat {
ipfw_insn o;
struct cfg_nat *nat;
} ipfw_insn_nat;
/* Apply ipv6 mask on ipv6 addr */
#define APPLY_MASK(addr,mask) \
(addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \
(addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \
(addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \
(addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3];
/* Structure for ipv6 */
typedef struct _ipfw_insn_ip6 {
ipfw_insn o;
struct in6_addr addr6;
struct in6_addr mask6;
} ipfw_insn_ip6;
/* Used to support icmp6 types */
typedef struct _ipfw_insn_icmp6 {
ipfw_insn o;
uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h
* define ICMP6_MAXTYPE
* as follows: n = ICMP6_MAXTYPE/32 + 1
* Actually is 203
*/
} ipfw_insn_icmp6;
/*
* Here we have the structure representing an ipfw rule.
*
* It starts with a general area (with link fields and counters)
* followed by an array of one or more instructions, which the code
* accesses as an array of 32-bit values.
*
* Given a rule pointer r:
*
* r->cmd is the start of the first instruction.
* ACTION_PTR(r) is the start of the first action (things to do
* once a rule matched).
*
* When assembling instruction, remember the following:
*
* + if a rule has a "keep-state" (or "limit") option, then the
* first instruction (at r->cmd) MUST BE an O_PROBE_STATE
* + if a rule has a "log" option, then the first action
* (at ACTION_PTR(r)) MUST be O_LOG
* + if a rule has an "altq" option, it comes after "log"
* + if a rule has an O_TAG option, it comes after "log" and "altq"
*
* NOTE: we use a simple linked list of rules because we never need
* to delete a rule without scanning the list. We do not use
* queue(3) macros for portability and readability.
*/
struct ip_fw {
struct ip_fw *next; /* linked list of rules */
struct ip_fw *next_rule; /* ptr to next [skipto] rule */
/* 'next_rule' is used to pass up 'set_disable' status */
u_int16_t act_ofs; /* offset of action in 32-bit units */
u_int16_t cmd_len; /* # of 32-bit words in cmd */
u_int16_t rulenum; /* rule number */
u_int8_t set; /* rule set (0..31) */
#define RESVD_SET 31 /* set for default and persistent rules */
u_int8_t _pad; /* padding */
/* These fields are present in all rules. */
u_int64_t pcnt; /* Packet counter */
u_int64_t bcnt; /* Byte counter */
u_int32_t timestamp; /* tv_sec of last match */
ipfw_insn cmd[1]; /* storage for commands */
};
#define ACTION_PTR(rule) \
(ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
#define RULESIZE(rule) (sizeof(struct ip_fw) + \
((struct ip_fw *)(rule))->cmd_len * 4 - 4)
/*
* This structure is used as a flow mask and a flow id for various
* parts of the code.
*/
struct ipfw_flow_id {
u_int32_t dst_ip;
u_int32_t src_ip;
u_int16_t dst_port;
u_int16_t src_port;
u_int8_t fib;
u_int8_t proto;
u_int8_t flags; /* protocol-specific flags */
uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */
struct in6_addr dst_ip6; /* could also store MAC addr! */
struct in6_addr src_ip6;
u_int32_t flow_id6;
u_int32_t frag_id6;
};
#define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6)
/*
* Dynamic ipfw rule.
*/
typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
struct _ipfw_dyn_rule {
ipfw_dyn_rule *next; /* linked list of rules. */
struct ip_fw *rule; /* pointer to rule */
/* 'rule' is used to pass up the rule number (from the parent) */
ipfw_dyn_rule *parent; /* pointer to parent rule */
u_int64_t pcnt; /* packet match counter */
u_int64_t bcnt; /* byte match counter */
struct ipfw_flow_id id; /* (masked) flow id */
u_int32_t expire; /* expire time */
u_int32_t bucket; /* which bucket in hash table */
u_int32_t state; /* state of this rule (typically a
* combination of TCP flags)
*/
u_int32_t ack_fwd; /* most recent ACKs in forward */
u_int32_t ack_rev; /* and reverse directions (used */
/* to generate keepalives) */
u_int16_t dyn_type; /* rule type */
u_int16_t count; /* refcount */
};
/*
* Definitions for IP option names.
*/
#define IP_FW_IPOPT_LSRR 0x01
#define IP_FW_IPOPT_SSRR 0x02
#define IP_FW_IPOPT_RR 0x04
#define IP_FW_IPOPT_TS 0x08
/*
* Definitions for TCP option names.
*/
#define IP_FW_TCPOPT_MSS 0x01
#define IP_FW_TCPOPT_WINDOW 0x02
#define IP_FW_TCPOPT_SACK 0x04
#define IP_FW_TCPOPT_TS 0x08
#define IP_FW_TCPOPT_CC 0x10
#define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
#define ICMP6_UNREACH_RST 0x100 /* fake ICMPv6 code (send a TCP RST) */
/*
* These are used for lookup tables.
*/
typedef struct _ipfw_table_entry {
in_addr_t addr; /* network address */
u_int32_t value; /* value */
u_int16_t tbl; /* table number */
u_int8_t masklen; /* mask length */
} ipfw_table_entry;
typedef struct _ipfw_table {
u_int32_t size; /* size of entries in bytes */
u_int32_t cnt; /* # of entries */
u_int16_t tbl; /* table number */
ipfw_table_entry ent[0]; /* entries */
} ipfw_table;
#define IP_FW_TABLEARG 65535
/*
* Main firewall chains definitions and global var's definitions.
*/
#ifdef _KERNEL
/* Return values from ipfw_chk() */
enum {
IP_FW_PASS = 0,
IP_FW_DENY,
IP_FW_DIVERT,
IP_FW_TEE,
IP_FW_DUMMYNET,
IP_FW_NETGRAPH,
IP_FW_NGTEE,
IP_FW_NAT,
};
/* flags for divert mtag */
#define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000
#define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000
/*
* Structure for collecting parameters to dummynet for ip6_output forwarding
*/
struct _ip6dn_args {
struct ip6_pktopts *opt_or;
struct route_in6 ro_or;
int flags_or;
struct ip6_moptions *im6o_or;
struct ifnet *origifp_or;
struct ifnet *ifp_or;
struct sockaddr_in6 dst_or;
u_long mtu_or;
struct route_in6 ro_pmtu_or;
};
/*
* Arguments for calling ipfw_chk() and dummynet_io(). We put them
* all into a structure because this way it is easier and more
* efficient to pass variables around and extend the interface.
*/
struct ip_fw_args {
struct mbuf *m; /* the mbuf chain */
struct ifnet *oif; /* output interface */
struct sockaddr_in *next_hop; /* forward address */
struct ip_fw *rule; /* matching rule */
struct ether_header *eh; /* for bridged packets */
struct ipfw_flow_id f_id; /* grabbed from IP header */
u_int32_t cookie; /* a cookie depending on rule action */
struct inpcb *inp;
struct _ip6dn_args dummypar; /* dummynet->ip6_output */
struct sockaddr_in hopstore; /* store here if cannot use a pointer */
};
/*
* Function definitions.
*/
/* Firewall hooks */
struct sockopt;
struct dn_flow_set;
int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
int ipfw_chk(struct ip_fw_args *);
int ipfw_init(void);
void ipfw_destroy(void);
typedef int ip_fw_ctl_t(struct sockopt *);
extern ip_fw_ctl_t *ip_fw_ctl_ptr;
extern int fw_one_pass;
extern int fw_enable;
#ifdef INET6
extern int fw6_enable;
#endif
/* For kernel ipfw_ether and ipfw_bridge. */
typedef int ip_fw_chk_t(struct ip_fw_args *args);
extern ip_fw_chk_t *ip_fw_chk_ptr;
#define IPFW_LOADED (ip_fw_chk_ptr != NULL)
#ifdef IPFW_INTERNAL
#define IPFW_TABLES_MAX 128
struct ip_fw_chain {
struct ip_fw *rules; /* list of rules */
struct ip_fw *reap; /* list of rules to reap */
LIST_HEAD(, cfg_nat) nat; /* list of nat entries */
struct radix_node_head *tables[IPFW_TABLES_MAX];
struct rwlock rwmtx;
};
#define IPFW_LOCK_INIT(_chain) \
rw_init(&(_chain)->rwmtx, "IPFW static rules")
#define IPFW_LOCK_DESTROY(_chain) rw_destroy(&(_chain)->rwmtx)
#define IPFW_WLOCK_ASSERT(_chain) rw_assert(&(_chain)->rwmtx, RA_WLOCKED)
#define IPFW_RLOCK(p) rw_rlock(&(p)->rwmtx)
#define IPFW_RUNLOCK(p) rw_runlock(&(p)->rwmtx)
#define IPFW_WLOCK(p) rw_wlock(&(p)->rwmtx)
#define IPFW_WUNLOCK(p) rw_wunlock(&(p)->rwmtx)
#define LOOKUP_NAT(l, i, p) do { \
LIST_FOREACH((p), &(l.nat), _next) { \
if ((p)->id == (i)) { \
break; \
} \
} \
} while (0)
typedef int ipfw_nat_t(struct ip_fw_args *, struct cfg_nat *, struct mbuf *);
typedef int ipfw_nat_cfg_t(struct sockopt *);
#endif
#endif /* _KERNEL */
#endif /* _IPFW2_H */
