3f48bf186f
refers to the size of the whole ethernet packet, just the DHCP message within the UDP payload, or something else. bootpd interpreted it as a maximum UDP payload size, so it could end up sending fragmented packets to clients (such as some versions of Etherboot) that used different interpretations of the maximum message size. Switch to the most conservative interpretation: ensure that the ethernet packet containing the response is no larger than the specified maximum message size. This matches the behaviour of the ISC dhcpd. MFC after: 1 week
150 lines
5.0 KiB
C
150 lines
5.0 KiB
C
/************************************************************************
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Copyright 1988, 1991 by Carnegie Mellon University
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted, provided
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that the above copyright notice appear in all copies and that both that
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copyright notice and this permission notice appear in supporting
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documentation, and that the name of Carnegie Mellon University not be used
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in advertising or publicity pertaining to distribution of the software
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without specific, written prior permission.
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CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
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SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL CMU BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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SOFTWARE.
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************************************************************************/
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/*
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* Bootstrap Protocol (BOOTP). RFC951 and RFC1395.
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*
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* $FreeBSD$
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*
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*
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* This file specifies the "implementation-independent" BOOTP protocol
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* information which is common to both client and server.
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*
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*/
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#include "bptypes.h" /* for int32, u_int32 */
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#define BP_CHADDR_LEN 16
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#define BP_SNAME_LEN 64
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#define BP_FILE_LEN 128
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#define BP_VEND_LEN 64
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#define BP_MINPKTSZ 300 /* to check sizeof(struct bootp) */
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/* Overhead to fit a bootp message into an Ethernet packet. */
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#define BP_MSG_OVERHEAD (14 + 20 + 8) /* Ethernet + IP + UDP headers */
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struct bootp {
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unsigned char bp_op; /* packet opcode type */
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unsigned char bp_htype; /* hardware addr type */
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unsigned char bp_hlen; /* hardware addr length */
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unsigned char bp_hops; /* gateway hops */
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u_int32 bp_xid; /* transaction ID */
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unsigned short bp_secs; /* seconds since boot began */
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unsigned short bp_flags; /* RFC1532 broadcast, etc. */
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struct in_addr bp_ciaddr; /* client IP address */
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struct in_addr bp_yiaddr; /* 'your' IP address */
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struct in_addr bp_siaddr; /* server IP address */
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struct in_addr bp_giaddr; /* gateway IP address */
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unsigned char bp_chaddr[BP_CHADDR_LEN]; /* client hardware address */
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char bp_sname[BP_SNAME_LEN]; /* server host name */
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char bp_file[BP_FILE_LEN]; /* boot file name */
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unsigned char bp_vend[BP_VEND_LEN]; /* vendor-specific area */
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/* note that bp_vend can be longer, extending to end of packet. */
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};
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/*
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* UDP port numbers, server and client.
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*/
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#define IPPORT_BOOTPS 67
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#define IPPORT_BOOTPC 68
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#define BOOTREPLY 2
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#define BOOTREQUEST 1
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/*
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* Hardware types from Assigned Numbers RFC.
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*/
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#define HTYPE_ETHERNET 1
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#define HTYPE_EXP_ETHERNET 2
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#define HTYPE_AX25 3
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#define HTYPE_PRONET 4
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#define HTYPE_CHAOS 5
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#define HTYPE_IEEE802 6
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#define HTYPE_ARCNET 7
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/*
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* Vendor magic cookie (v_magic) for CMU
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*/
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#define VM_CMU "CMU"
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/*
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* Vendor magic cookie (v_magic) for RFC1048
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*/
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#define VM_RFC1048 { 99, 130, 83, 99 }
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/*
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* Tag values used to specify what information is being supplied in
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* the vendor (options) data area of the packet.
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*/
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/* RFC 1048 */
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#define TAG_END ((unsigned char) 255)
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#define TAG_PAD ((unsigned char) 0)
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#define TAG_SUBNET_MASK ((unsigned char) 1)
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#define TAG_TIME_OFFSET ((unsigned char) 2)
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#define TAG_GATEWAY ((unsigned char) 3)
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#define TAG_TIME_SERVER ((unsigned char) 4)
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#define TAG_NAME_SERVER ((unsigned char) 5)
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#define TAG_DOMAIN_SERVER ((unsigned char) 6)
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#define TAG_LOG_SERVER ((unsigned char) 7)
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#define TAG_COOKIE_SERVER ((unsigned char) 8)
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#define TAG_LPR_SERVER ((unsigned char) 9)
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#define TAG_IMPRESS_SERVER ((unsigned char) 10)
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#define TAG_RLP_SERVER ((unsigned char) 11)
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#define TAG_HOST_NAME ((unsigned char) 12)
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#define TAG_BOOT_SIZE ((unsigned char) 13)
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/* RFC 1395 */
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#define TAG_DUMP_FILE ((unsigned char) 14)
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#define TAG_DOMAIN_NAME ((unsigned char) 15)
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#define TAG_SWAP_SERVER ((unsigned char) 16)
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#define TAG_ROOT_PATH ((unsigned char) 17)
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/* RFC 1497 */
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#define TAG_EXTEN_FILE ((unsigned char) 18)
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/* RFC 1533 */
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#define TAG_NIS_DOMAIN ((unsigned char) 40)
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#define TAG_NIS_SERVER ((unsigned char) 41)
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#define TAG_NTP_SERVER ((unsigned char) 42)
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/* DHCP maximum message size. */
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#define TAG_MAX_MSGSZ ((unsigned char) 57)
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/* XXX - Add new tags here */
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/*
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* "vendor" data permitted for CMU bootp clients.
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*/
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struct cmu_vend {
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char v_magic[4]; /* magic number */
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u_int32 v_flags; /* flags/opcodes, etc. */
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struct in_addr v_smask; /* Subnet mask */
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struct in_addr v_dgate; /* Default gateway */
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struct in_addr v_dns1, v_dns2; /* Domain name servers */
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struct in_addr v_ins1, v_ins2; /* IEN-116 name servers */
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struct in_addr v_ts1, v_ts2; /* Time servers */
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int32 v_unused[6]; /* currently unused */
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};
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/* v_flags values */
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#define VF_SMASK 1 /* Subnet mask field contains valid data */
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