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freebsd/sys/netinet/ip_fw.h
Robert Watson 65450f2f77 o IPFW incorrectly handled filtering in the presence of previously 
reserved and now allocated TCP flags in incoming packets.  This patch
  stops overloading those bits in the IP firewall rules, and moves
  colliding flags to a seperate field, ipflg.  The IPFW userland
  management tool, ipfw(8), is updated to reflect this change.  New TCP
  flags related to ECN are now included in tcp.h for reference, although
  we don't currently implement TCP+ECN.

o To use this fix without completely rebuilding, it is sufficient to copy
  ip_fw.h and tcp.h into your appropriate include directory, then rebuild
  the ipfw kernel module, and ipfw tool, and install both.  Note that a
  mismatch between module and userland tool will result in incorrect
  installation of firewall rules that may have unexpected effects.  This
  is an MFC candidate, following shakedown.  This bug does not appear
  to affect ipfilter.

Reviewed by:	security-officer, billf
Reported by:	Aragon Gouveia <aragon@phat.za.net>
2001-01-09 03:10:30 +00:00

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/*
* Copyright (c) 1993 Daniel Boulet
* Copyright (c) 1994 Ugen J.S.Antsilevich
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
* Obviously, it would be nice if you gave credit where credit is due
* but requiring it would be too onerous.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* $FreeBSD$
*/
#ifndef _IP_FW_H
#define _IP_FW_H
#include <sys/queue.h>
/*
* This union structure identifies an interface, either explicitly
* by name or implicitly by IP address. The flags IP_FW_F_IIFNAME
* and IP_FW_F_OIFNAME say how to interpret this structure. An
* interface unit number of -1 matches any unit number, while an
* IP address of 0.0.0.0 indicates matches any interface.
*
* The receive and transmit interfaces are only compared against the
* the packet if the corresponding bit (IP_FW_F_IIFACE or IP_FW_F_OIFACE)
* is set. Note some packets lack a receive or transmit interface
* (in which case the missing "interface" never matches).
*/
union ip_fw_if {
struct in_addr fu_via_ip; /* Specified by IP address */
struct { /* Specified by interface name */
#define FW_IFNLEN 10 /* need room ! was IFNAMSIZ */
char name[FW_IFNLEN];
short unit; /* -1 means match any unit */
} fu_via_if;
};
/*
* Format of an IP firewall descriptor
*
* fw_src, fw_dst, fw_smsk, fw_dmsk are always stored in network byte order.
* fw_flg and fw_n*p are stored in host byte order (of course).
* Port numbers are stored in HOST byte order.
*/
struct ip_fw {
u_int64_t fw_pcnt,fw_bcnt; /* Packet and byte counters */
struct in_addr fw_src, fw_dst; /* Source and destination IP addr */
struct in_addr fw_smsk, fw_dmsk; /* Mask for src and dest IP addr */
u_short fw_number; /* Rule number */
u_int fw_flg; /* Operational Flags word */
#define IP_FW_MAX_PORTS 10 /* A reasonable maximum */
union {
u_short fw_pts[IP_FW_MAX_PORTS]; /* Array of port numbers to match */
#define IP_FW_ICMPTYPES_MAX 128
#define IP_FW_ICMPTYPES_DIM (IP_FW_ICMPTYPES_MAX / (sizeof(unsigned) * 8))
unsigned fw_icmptypes[IP_FW_ICMPTYPES_DIM]; /* ICMP types bitmap */
} fw_uar;
u_int fw_ipflg; /* IP flags word */
u_char fw_ipopt,fw_ipnopt; /* IP options set/unset */
u_short fw_iplen, fw_ipid; /* IP length, identification */
u_char fw_iptos, fw_ipntos; /* IP type of service set/unset */
u_char fw_ipttl; /* IP time to live */
u_int fw_ipver:4; /* IP version */
u_char fw_tcpopt,fw_tcpnopt; /* TCP options set/unset */
u_char fw_tcpf,fw_tcpnf; /* TCP flags set/unset */
u_int32_t fw_tcpseq, fw_tcpack; /* TCP sequence and acknowledgement */
u_short fw_tcpwin; /* TCP window size */
long timestamp; /* timestamp (tv_sec) of last match */
union ip_fw_if fw_in_if, fw_out_if; /* Incoming and outgoing interfaces */
union {
u_short fu_divert_port; /* Divert/tee port (options IPDIVERT) */
u_short fu_pipe_nr; /* queue number (option DUMMYNET) */
u_short fu_skipto_rule; /* SKIPTO command rule number */
u_short fu_reject_code; /* REJECT response code */
struct sockaddr_in fu_fwd_ip;
} fw_un;
u_char fw_prot; /* IP protocol */
/*
* N'of src ports and # of dst ports in ports array (dst ports
* follow src ports; max of 10 ports in all; count of 0 means
* match all ports)
*/
u_char fw_nports;
void *pipe_ptr; /* flow_set ptr for dummynet pipe */
void *next_rule_ptr ; /* next rule in case of match */
uid_t fw_uid; /* uid to match */
gid_t fw_gid; /* gid to match */
int fw_logamount; /* amount to log */
u_int64_t fw_loghighest; /* highest number packet to log */
};
/*
* extended ipfw structure... some fields in the original struct
* can be used to pass parameters up/down, namely pointers
* void *pipe_ptr
* void *next_rule_ptr
* some others can be used to pass parameters down, namely counters etc.
* u_int64_t fw_pcnt,fw_bcnt;
* long timestamp;
*/
struct ip_fw_ext { /* extended structure */
struct ip_fw rule; /* must be at offset 0 */
long dont_match_prob; /* 0x7fffffff means 1.0, always fail */
u_int dyn_type; /* type for dynamic rule */
};
#define IP_FW_GETNSRCP(rule) ((rule)->fw_nports & 0x0f)
#define IP_FW_SETNSRCP(rule, n) do { \
(rule)->fw_nports &= ~0x0f; \
(rule)->fw_nports |= (n); \
} while (0)
#define IP_FW_GETNDSTP(rule) ((rule)->fw_nports >> 4)
#define IP_FW_SETNDSTP(rule, n) do { \
(rule)->fw_nports &= ~0xf0; \
(rule)->fw_nports |= (n) << 4;\
} while (0)
#define fw_divert_port fw_un.fu_divert_port
#define fw_skipto_rule fw_un.fu_skipto_rule
#define fw_reject_code fw_un.fu_reject_code
#define fw_pipe_nr fw_un.fu_pipe_nr
#define fw_fwd_ip fw_un.fu_fwd_ip
struct ip_fw_chain {
LIST_ENTRY(ip_fw_chain) chain;
struct ip_fw *rule;
};
/*
* Flow mask/flow id for each queue.
*/
struct ipfw_flow_id {
u_int32_t dst_ip, src_ip ;
u_int16_t dst_port, src_port ;
u_int8_t proto ;
u_int8_t flags ; /* protocol-specific flags */
} ;
/*
* dynamic ipfw rule
*/
struct ipfw_dyn_rule {
struct ipfw_dyn_rule *next ;
struct ipfw_flow_id id ;
struct ipfw_flow_id mask ;
struct ip_fw_chain *chain ; /* pointer to parent rule */
u_int32_t type ; /* rule type */
u_int32_t expire ; /* expire time */
u_int64_t pcnt, bcnt; /* match counters */
u_int32_t bucket ; /* which bucket in hash table */
u_int32_t state ; /* state of this rule (typ. a */
/* combination of TCP flags) */
} ;
/*
* Values for "flags" field .
*/
#define IP_FW_F_COMMAND 0x000000ff /* Mask for type of chain entry: */
#define IP_FW_F_DENY 0x00000000 /* This is a deny rule */
#define IP_FW_F_REJECT 0x00000001 /* Deny and send a response packet */
#define IP_FW_F_ACCEPT 0x00000002 /* This is an accept rule */
#define IP_FW_F_COUNT 0x00000003 /* This is a count rule */
#define IP_FW_F_DIVERT 0x00000004 /* This is a divert rule */
#define IP_FW_F_TEE 0x00000005 /* This is a tee rule */
#define IP_FW_F_SKIPTO 0x00000006 /* This is a skipto rule */
#define IP_FW_F_FWD 0x00000007 /* This is a "change forwarding address" rule */
#define IP_FW_F_PIPE 0x00000008 /* This is a dummynet rule */
#define IP_FW_F_QUEUE 0x00000009 /* This is a dummynet queue */
#define IP_FW_F_IN 0x00000100 /* Check inbound packets */
#define IP_FW_F_OUT 0x00000200 /* Check outbound packets */
#define IP_FW_F_IIFACE 0x00000400 /* Apply inbound interface test */
#define IP_FW_F_OIFACE 0x00000800 /* Apply outbound interface test */
#define IP_FW_F_PRN 0x00001000 /* Print if this rule matches */
#define IP_FW_F_SRNG 0x00002000 /* The first two src ports are a min *
* and max range (stored in host byte *
* order). */
#define IP_FW_F_DRNG 0x00004000 /* The first two dst ports are a min *
* and max range (stored in host byte *
* order). */
#define IP_FW_F_FRAG 0x00008000 /* Fragment */
#define IP_FW_F_IIFNAME 0x00010000 /* In interface by name/unit (not IP) */
#define IP_FW_F_OIFNAME 0x00020000 /* Out interface by name/unit (not IP) */
#define IP_FW_F_INVSRC 0x00040000 /* Invert sense of src check */
#define IP_FW_F_INVDST 0x00080000 /* Invert sense of dst check */
#define IP_FW_F_ICMPBIT 0x00100000 /* ICMP type bitmap is valid */
#define IP_FW_F_UID 0x00200000 /* filter by uid */
#define IP_FW_F_GID 0x00400000 /* filter by gid */
#define IP_FW_F_RND_MATCH 0x00800000 /* probabilistic rule match */
#define IP_FW_F_SMSK 0x01000000 /* src-port + mask */
#define IP_FW_F_DMSK 0x02000000 /* dst-port + mask */
#define IP_FW_BRIDGED 0x04000000 /* only match bridged packets */
#define IP_FW_F_KEEP_S 0x08000000 /* keep state */
#define IP_FW_F_CHECK_S 0x10000000 /* check state */
#define IP_FW_F_MASK 0x1FFFFFFF /* All possible flag bits mask */
/*
* Flags for the 'fw_ipflg' field, for comparing values of ip and its protocols.
*/
#define IP_FW_IF_TCPOPT 0x00000001 /* tcp options */
#define IP_FW_IF_TCPFLG 0x00000002 /* tcp flags */
#define IP_FW_IF_TCPSEQ 0x00000004 /* tcp sequence number */
#define IP_FW_IF_TCPACK 0x00000008 /* tcp acknowledgement number */
#define IP_FW_IF_TCPWIN 0x00000010 /* tcp window size */
#define IP_FW_IF_TCPEST 0x00000020 /* established TCP connection */
#define IP_FW_IF_TCPMSK 0x0000003f /* mask of all tcp values */
#define IP_FW_IF_IPOPT 0x00000100 /* ip options */
#define IP_FW_IF_IPLEN 0x00000200 /* ip length */
#define IP_FW_IF_IPID 0x00000400 /* ip identification */
#define IP_FW_IF_IPTOS 0x00000800 /* ip type of service */
#define IP_FW_IF_IPTTL 0x00001000 /* ip time to live */
#define IP_FW_IF_IPVER 0x00002000 /* ip version */
#define IP_FW_IF_IPMSK 0x00003f00 /* mask of all ip values */
#define IP_FW_IF_MSK 0x0000ffff /* All possible bits mask */
/*
* For backwards compatibility with rules specifying "via iface" but
* not restricted to only "in" or "out" packets, we define this combination
* of bits to represent this configuration.
*/
#define IF_FW_F_VIAHACK (IP_FW_F_IN|IP_FW_F_OUT|IP_FW_F_IIFACE|IP_FW_F_OIFACE)
/*
* Definitions for REJECT response codes.
* Values less than 256 correspond to ICMP unreachable codes.
*/
#define IP_FW_REJECT_RST 0x0100 /* TCP packets: send RST */
/*
* 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
/*
* Definitions for TCP flags.
*/
#define IP_FW_TCPF_FIN TH_FIN
#define IP_FW_TCPF_SYN TH_SYN
#define IP_FW_TCPF_RST TH_RST
#define IP_FW_TCPF_PSH TH_PUSH
#define IP_FW_TCPF_ACK TH_ACK
#define IP_FW_TCPF_URG TH_URG
/*
* Main firewall chains definitions and global var's definitions.
*/
#ifdef _KERNEL
#define IP_FW_PORT_DYNT_FLAG 0x10000
#define IP_FW_PORT_TEE_FLAG 0x20000
/*
* Function definitions.
*/
void ip_fw_init __P((void));
/* Firewall hooks */
struct ip;
struct sockopt;
typedef int ip_fw_chk_t __P((struct ip **, int, struct ifnet *, u_int16_t *,
struct mbuf **, struct ip_fw_chain **, struct sockaddr_in **));
typedef int ip_fw_ctl_t __P((struct sockopt *));
extern ip_fw_chk_t *ip_fw_chk_ptr;
extern ip_fw_ctl_t *ip_fw_ctl_ptr;
extern int fw_one_pass;
extern int fw_enable;
extern struct ipfw_flow_id last_pkt ;
#endif /* _KERNEL */
#endif /* _IP_FW_H */
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