e4676ba603
these are quite extensive additions to the ipfw code. they include a change to the API because the old method was broken, but the user view is kept the same. The new code allows a particular match to skip forward to a particular line number, so that blocks of rules can be used without checking all the intervening rules. There are also many more ways of rejecting connections especially TCP related, and many many more ... see the man page for a complete description.
182 lines
6.1 KiB
C
182 lines
6.1 KiB
C
/*
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* Copyright (c) 1993 Daniel Boulet
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* Copyright (c) 1994 Ugen J.S.Antsilevich
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*
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* Redistribution and use in source forms, with and without modification,
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* are permitted provided that this entire comment appears intact.
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*
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* Redistribution in binary form may occur without any restrictions.
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* Obviously, it would be nice if you gave credit where credit is due
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* but requiring it would be too onerous.
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*
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* This software is provided ``AS IS'' without any warranties of any kind.
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*
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* $Id: ip_fw.h,v 1.1 1997/05/09 17:46:45 archie Exp $
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*/
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#ifndef _IP_FW_H
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#define _IP_FW_H
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/*
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* This union structure identifies an interface, either explicitly
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* by name or implicitly by IP address. The flags IP_FW_F_IIFNAME
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* and IP_FW_F_OIFNAME say how to interpret this structure. An
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* interface unit number of -1 matches any unit number, while an
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* IP address of 0.0.0.0 indicates matches any interface.
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*
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* The receive and transmit interfaces are only compared against the
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* the packet if the corresponding bit (IP_FW_F_IIFACE or IP_FW_F_OIFACE)
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* is set. Note some packets lack a receive or transmit interface
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* (in which case the missing "interface" never matches).
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*/
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union ip_fw_if {
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struct in_addr fu_via_ip; /* Specified by IP address */
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struct { /* Specified by interface name */
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#define FW_IFNLEN 6 /* To keep structure on 2^x boundary */
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char name[FW_IFNLEN];
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short unit; /* -1 means match any unit */
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} fu_via_if;
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};
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/*
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* Format of an IP firewall descriptor
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*
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* fw_src, fw_dst, fw_smsk, fw_dmsk are always stored in network byte order.
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* fw_flg and fw_n*p are stored in host byte order (of course).
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* Port numbers are stored in HOST byte order.
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* Warning: setsockopt() will fail if sizeof(struct ip_fw) > MLEN (108)
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*/
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struct ip_fw {
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u_long fw_pcnt,fw_bcnt; /* Packet and byte counters */
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struct in_addr fw_src, fw_dst; /* Source and destination IP addr */
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struct in_addr fw_smsk, fw_dmsk; /* Mask for src and dest IP addr */
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u_short fw_number; /* Rule number */
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u_short fw_flg; /* Flags word */
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#define IP_FW_MAX_PORTS 10 /* A reasonable maximum */
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u_short fw_pts[IP_FW_MAX_PORTS]; /* Array of port numbers to match */
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u_char fw_ipopt,fw_ipnopt; /* IP options set/unset */
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u_char fw_tcpf,fw_tcpnf; /* TCP flags set/unset */
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#define IP_FW_ICMPTYPES_DIM (256 / (sizeof(unsigned) * 8))
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unsigned fw_icmptypes[IP_FW_ICMPTYPES_DIM]; /* ICMP types bitmap */
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long timestamp; /* timestamp (tv_sec) of last match */
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union ip_fw_if fw_in_if, fw_out_if; /* Incoming and outgoing interfaces */
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union {
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u_short fu_divert_port; /* Divert/tee port (options IPDIVERT) */
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u_short fu_skipto_rule; /* SKIPTO command rule number */
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u_short fu_reject_code; /* REJECT response code */
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} fw_un;
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u_char fw_prot; /* IP protocol */
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u_char fw_nports; /* N'of src ports and # of dst ports */
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/* in ports array (dst ports follow */
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/* src ports; max of 10 ports in all; */
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/* count of 0 means match all ports) */
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};
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#define IP_FW_GETNSRCP(rule) ((rule)->fw_nports & 0x0f)
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#define IP_FW_SETNSRCP(rule, n) do { \
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(rule)->fw_nports &= ~0x0f; \
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(rule)->fw_nports |= (n); \
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} while (0)
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#define IP_FW_GETNDSTP(rule) ((rule)->fw_nports >> 4)
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#define IP_FW_SETNDSTP(rule, n) do { \
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(rule)->fw_nports &= ~0xf0; \
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(rule)->fw_nports |= (n) << 4;\
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} while (0)
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#define fw_divert_port fw_un.fu_divert_port
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#define fw_skipto_rule fw_un.fu_skipto_rule
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#define fw_reject_code fw_un.fu_reject_code
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struct ip_fw_chain {
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LIST_ENTRY(ip_fw_chain) chain;
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struct ip_fw *rule;
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};
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/*
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* Values for "flags" field .
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*/
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#define IP_FW_F_IN 0x0001 /* Check inbound packets */
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#define IP_FW_F_OUT 0x0002 /* Check outbound packets */
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#define IP_FW_F_IIFACE 0x0004 /* Apply inbound interface test */
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#define IP_FW_F_OIFACE 0x0008 /* Apply outbound interface test */
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#define IP_FW_F_COMMAND 0x0070 /* Mask for type of chain entry: */
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#define IP_FW_F_DENY 0x0000 /* This is a deny rule */
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#define IP_FW_F_REJECT 0x0010 /* Deny and send a response packet */
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#define IP_FW_F_ACCEPT 0x0020 /* This is an accept rule */
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#define IP_FW_F_COUNT 0x0030 /* This is a count rule */
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#define IP_FW_F_DIVERT 0x0040 /* This is a divert rule */
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#define IP_FW_F_TEE 0x0050 /* This is a tee rule */
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#define IP_FW_F_SKIPTO 0x0060 /* This is a skipto rule */
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#define IP_FW_F_PRN 0x0080 /* Print if this rule matches */
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#define IP_FW_F_SRNG 0x0100 /* The first two src ports are a min *
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* and max range (stored in host byte *
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* order). */
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#define IP_FW_F_DRNG 0x0200 /* The first two dst ports are a min *
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* and max range (stored in host byte *
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* order). */
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#define IP_FW_F_IIFNAME 0x0400 /* In interface by name/unit (not IP) */
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#define IP_FW_F_OIFNAME 0x0800 /* Out interface by name/unit (not IP) */
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#define IP_FW_F_INVSRC 0x1000 /* Invert sense of src check */
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#define IP_FW_F_INVDST 0x2000 /* Invert sense of dst check */
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#define IP_FW_F_FRAG 0x4000 /* Fragment */
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#define IP_FW_F_ICMPBIT 0x8000 /* ICMP type bitmap is valid */
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#define IP_FW_F_MASK 0xFFFF /* All possible flag bits mask */
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/*
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* For backwards compatibility with rules specifying "via iface" but
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* not restricted to only "in" or "out" packets, we define this combination
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* of bits to represent this configuration.
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*/
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#define IF_FW_F_VIAHACK (IP_FW_F_IN|IP_FW_F_OUT|IP_FW_F_IIFACE|IP_FW_F_OIFACE)
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/*
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* Definitions for REJECT response codes.
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* Values less than 256 correspond to ICMP unreachable codes.
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*/
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#define IP_FW_REJECT_RST 0x0100 /* TCP packets: send RST */
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/*
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* Definitions for IP option names.
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*/
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#define IP_FW_IPOPT_LSRR 0x01
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#define IP_FW_IPOPT_SSRR 0x02
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#define IP_FW_IPOPT_RR 0x04
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#define IP_FW_IPOPT_TS 0x08
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/*
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* Definitions for TCP flags.
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*/
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#define IP_FW_TCPF_FIN TH_FIN
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#define IP_FW_TCPF_SYN TH_SYN
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#define IP_FW_TCPF_RST TH_RST
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#define IP_FW_TCPF_PSH TH_PUSH
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#define IP_FW_TCPF_ACK TH_ACK
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#define IP_FW_TCPF_URG TH_URG
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#define IP_FW_TCPF_ESTAB 0x40
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/*
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* Main firewall chains definitions and global var's definitions.
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*/
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#ifdef KERNEL
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/*
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* Function definitions.
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*/
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void ip_fw_init(void);
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#endif /* KERNEL */
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#endif /* _IP_FW_H */
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