X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/e89409254248af64db721ede4babbe9fd1753f6c..d6aacc676d8540f31d1df72b12b43fc9cde93df6:/print-bootp.c diff --git a/print-bootp.c b/print-bootp.c index 51cc395d..83fa0278 100644 --- a/print-bootp.c +++ b/print-bootp.c @@ -20,191 +20,411 @@ * * Format and print bootp packets. */ -#ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-bootp.c,v 1.51 2000-09-23 08:03:33 guy Exp $ (LBL)"; -#endif #ifdef HAVE_CONFIG_H #include "config.h" #endif -#include -#include -#include - -struct mbuf; -struct rtentry; -#include +#include -#include - -#include -#include #include -#include "interface.h" +#include "netdissect.h" #include "addrtoname.h" -#include "ether.h" -#include "bootp.h" +#include "extract.h" -static void rfc1048_print(const u_char *, u_int); -static void cmu_print(const u_char *, u_int); +static const char tstr[] = " [|bootp]"; -static char tstr[] = " [|bootp]"; +/* + * Bootstrap Protocol (BOOTP). RFC951 and RFC1048. + * + * This file specifies the "implementation-independent" BOOTP protocol + * information which is common to both client and server. + * + * Copyright 1988 by Carnegie Mellon. + * + * Permission to use, copy, modify, and distribute this program for any + * purpose and without fee is hereby granted, provided that this copyright + * and permission notice appear on all copies and supporting documentation, + * the name of Carnegie Mellon not be used in advertising or publicity + * pertaining to distribution of the program without specific prior + * permission, and notice be given in supporting documentation that copying + * and distribution is by permission of Carnegie Mellon and Stanford + * University. Carnegie Mellon makes no representations about the + * suitability of this software for any purpose. It is provided "as is" + * without express or implied warranty. + */ + +struct bootp { + uint8_t bp_op; /* packet opcode type */ + uint8_t bp_htype; /* hardware addr type */ + uint8_t bp_hlen; /* hardware addr length */ + uint8_t bp_hops; /* gateway hops */ + uint32_t bp_xid; /* transaction ID */ + uint16_t bp_secs; /* seconds since boot began */ + uint16_t bp_flags; /* flags - see bootp_flag_values[] + in print-bootp.c */ + struct in_addr bp_ciaddr; /* client IP address */ + struct in_addr bp_yiaddr; /* 'your' IP address */ + struct in_addr bp_siaddr; /* server IP address */ + struct in_addr bp_giaddr; /* gateway IP address */ + uint8_t bp_chaddr[16]; /* client hardware address */ + uint8_t bp_sname[64]; /* server host name */ + uint8_t bp_file[128]; /* boot file name */ + uint8_t bp_vend[64]; /* vendor-specific area */ +} UNALIGNED; + +#define BOOTPREPLY 2 +#define BOOTPREQUEST 1 + +/* + * Vendor magic cookie (v_magic) for CMU + */ +#define VM_CMU "CMU" + +/* + * Vendor magic cookie (v_magic) for RFC1048 + */ +#define VM_RFC1048 { 99, 130, 83, 99 } + +/* + * RFC1048 tag values used to specify what information is being supplied in + * the vendor field of the packet. + */ + +#define TAG_PAD ((uint8_t) 0) +#define TAG_SUBNET_MASK ((uint8_t) 1) +#define TAG_TIME_OFFSET ((uint8_t) 2) +#define TAG_GATEWAY ((uint8_t) 3) +#define TAG_TIME_SERVER ((uint8_t) 4) +#define TAG_NAME_SERVER ((uint8_t) 5) +#define TAG_DOMAIN_SERVER ((uint8_t) 6) +#define TAG_LOG_SERVER ((uint8_t) 7) +#define TAG_COOKIE_SERVER ((uint8_t) 8) +#define TAG_LPR_SERVER ((uint8_t) 9) +#define TAG_IMPRESS_SERVER ((uint8_t) 10) +#define TAG_RLP_SERVER ((uint8_t) 11) +#define TAG_HOSTNAME ((uint8_t) 12) +#define TAG_BOOTSIZE ((uint8_t) 13) +#define TAG_END ((uint8_t) 255) +/* RFC1497 tags */ +#define TAG_DUMPPATH ((uint8_t) 14) +#define TAG_DOMAINNAME ((uint8_t) 15) +#define TAG_SWAP_SERVER ((uint8_t) 16) +#define TAG_ROOTPATH ((uint8_t) 17) +#define TAG_EXTPATH ((uint8_t) 18) +/* RFC2132 */ +#define TAG_IP_FORWARD ((uint8_t) 19) +#define TAG_NL_SRCRT ((uint8_t) 20) +#define TAG_PFILTERS ((uint8_t) 21) +#define TAG_REASS_SIZE ((uint8_t) 22) +#define TAG_DEF_TTL ((uint8_t) 23) +#define TAG_MTU_TIMEOUT ((uint8_t) 24) +#define TAG_MTU_TABLE ((uint8_t) 25) +#define TAG_INT_MTU ((uint8_t) 26) +#define TAG_LOCAL_SUBNETS ((uint8_t) 27) +#define TAG_BROAD_ADDR ((uint8_t) 28) +#define TAG_DO_MASK_DISC ((uint8_t) 29) +#define TAG_SUPPLY_MASK ((uint8_t) 30) +#define TAG_DO_RDISC ((uint8_t) 31) +#define TAG_RTR_SOL_ADDR ((uint8_t) 32) +#define TAG_STATIC_ROUTE ((uint8_t) 33) +#define TAG_USE_TRAILERS ((uint8_t) 34) +#define TAG_ARP_TIMEOUT ((uint8_t) 35) +#define TAG_ETH_ENCAP ((uint8_t) 36) +#define TAG_TCP_TTL ((uint8_t) 37) +#define TAG_TCP_KEEPALIVE ((uint8_t) 38) +#define TAG_KEEPALIVE_GO ((uint8_t) 39) +#define TAG_NIS_DOMAIN ((uint8_t) 40) +#define TAG_NIS_SERVERS ((uint8_t) 41) +#define TAG_NTP_SERVERS ((uint8_t) 42) +#define TAG_VENDOR_OPTS ((uint8_t) 43) +#define TAG_NETBIOS_NS ((uint8_t) 44) +#define TAG_NETBIOS_DDS ((uint8_t) 45) +#define TAG_NETBIOS_NODE ((uint8_t) 46) +#define TAG_NETBIOS_SCOPE ((uint8_t) 47) +#define TAG_XWIN_FS ((uint8_t) 48) +#define TAG_XWIN_DM ((uint8_t) 49) +#define TAG_NIS_P_DOMAIN ((uint8_t) 64) +#define TAG_NIS_P_SERVERS ((uint8_t) 65) +#define TAG_MOBILE_HOME ((uint8_t) 68) +#define TAG_SMPT_SERVER ((uint8_t) 69) +#define TAG_POP3_SERVER ((uint8_t) 70) +#define TAG_NNTP_SERVER ((uint8_t) 71) +#define TAG_WWW_SERVER ((uint8_t) 72) +#define TAG_FINGER_SERVER ((uint8_t) 73) +#define TAG_IRC_SERVER ((uint8_t) 74) +#define TAG_STREETTALK_SRVR ((uint8_t) 75) +#define TAG_STREETTALK_STDA ((uint8_t) 76) +/* DHCP options */ +#define TAG_REQUESTED_IP ((uint8_t) 50) +#define TAG_IP_LEASE ((uint8_t) 51) +#define TAG_OPT_OVERLOAD ((uint8_t) 52) +#define TAG_TFTP_SERVER ((uint8_t) 66) +#define TAG_BOOTFILENAME ((uint8_t) 67) +#define TAG_DHCP_MESSAGE ((uint8_t) 53) +#define TAG_SERVER_ID ((uint8_t) 54) +#define TAG_PARM_REQUEST ((uint8_t) 55) +#define TAG_MESSAGE ((uint8_t) 56) +#define TAG_MAX_MSG_SIZE ((uint8_t) 57) +#define TAG_RENEWAL_TIME ((uint8_t) 58) +#define TAG_REBIND_TIME ((uint8_t) 59) +#define TAG_VENDOR_CLASS ((uint8_t) 60) +#define TAG_CLIENT_ID ((uint8_t) 61) +/* RFC 2241 */ +#define TAG_NDS_SERVERS ((uint8_t) 85) +#define TAG_NDS_TREE_NAME ((uint8_t) 86) +#define TAG_NDS_CONTEXT ((uint8_t) 87) +/* RFC 2242 */ +#define TAG_NDS_IPDOMAIN ((uint8_t) 62) +#define TAG_NDS_IPINFO ((uint8_t) 63) +/* RFC 2485 */ +#define TAG_OPEN_GROUP_UAP ((uint8_t) 98) +/* RFC 2563 */ +#define TAG_DISABLE_AUTOCONF ((uint8_t) 116) +/* RFC 2610 */ +#define TAG_SLP_DA ((uint8_t) 78) +#define TAG_SLP_SCOPE ((uint8_t) 79) +/* RFC 2937 */ +#define TAG_NS_SEARCH ((uint8_t) 117) +/* RFC 3004 - The User Class Option for DHCP */ +#define TAG_USER_CLASS ((uint8_t) 77) +/* RFC 3011 */ +#define TAG_IP4_SUBNET_SELECT ((uint8_t) 118) +/* RFC 3442 */ +#define TAG_CLASSLESS_STATIC_RT ((uint8_t) 121) +#define TAG_CLASSLESS_STA_RT_MS ((uint8_t) 249) +/* RFC 5859 - TFTP Server Address Option for DHCPv4 */ +#define TAG_TFTP_SERVER_ADDRESS ((uint8_t) 150) +/* ftp://ftp.isi.edu/.../assignments/bootp-dhcp-extensions */ +#define TAG_SLP_NAMING_AUTH ((uint8_t) 80) +#define TAG_CLIENT_FQDN ((uint8_t) 81) +#define TAG_AGENT_CIRCUIT ((uint8_t) 82) +#define TAG_AGENT_REMOTE ((uint8_t) 83) +#define TAG_AGENT_MASK ((uint8_t) 84) +#define TAG_TZ_STRING ((uint8_t) 88) +#define TAG_FQDN_OPTION ((uint8_t) 89) +#define TAG_AUTH ((uint8_t) 90) +#define TAG_VINES_SERVERS ((uint8_t) 91) +#define TAG_SERVER_RANK ((uint8_t) 92) +#define TAG_CLIENT_ARCH ((uint8_t) 93) +#define TAG_CLIENT_NDI ((uint8_t) 94) +#define TAG_CLIENT_GUID ((uint8_t) 97) +#define TAG_LDAP_URL ((uint8_t) 95) +#define TAG_6OVER4 ((uint8_t) 96) +#define TAG_PRINTER_NAME ((uint8_t) 100) +#define TAG_MDHCP_SERVER ((uint8_t) 101) +#define TAG_IPX_COMPAT ((uint8_t) 110) +#define TAG_NETINFO_PARENT ((uint8_t) 112) +#define TAG_NETINFO_PARENT_TAG ((uint8_t) 113) +#define TAG_URL ((uint8_t) 114) +#define TAG_FAILOVER ((uint8_t) 115) +#define TAG_EXTENDED_REQUEST ((uint8_t) 126) +#define TAG_EXTENDED_OPTION ((uint8_t) 127) + +/* DHCP Message types (values for TAG_DHCP_MESSAGE option) */ +#define DHCPDISCOVER 1 +#define DHCPOFFER 2 +#define DHCPREQUEST 3 +#define DHCPDECLINE 4 +#define DHCPACK 5 +#define DHCPNAK 6 +#define DHCPRELEASE 7 +#define DHCPINFORM 8 + +/* + * "vendor" data permitted for CMU bootp clients. + */ + +struct cmu_vend { + uint8_t v_magic[4]; /* magic number */ + uint32_t v_flags; /* flags/opcodes, etc. */ + struct in_addr v_smask; /* Subnet mask */ + struct in_addr v_dgate; /* Default gateway */ + struct in_addr v_dns1, v_dns2; /* Domain name servers */ + struct in_addr v_ins1, v_ins2; /* IEN-116 name servers */ + struct in_addr v_ts1, v_ts2; /* Time servers */ + uint8_t v_unused[24]; /* currently unused */ +} UNALIGNED; + + +/* v_flags values */ +#define VF_SMASK 1 /* Subnet mask field contains valid data */ + +/* RFC 4702 DHCP Client FQDN Option */ + +#define CLIENT_FQDN_FLAGS_S 0x01 +#define CLIENT_FQDN_FLAGS_O 0x02 +#define CLIENT_FQDN_FLAGS_E 0x04 +#define CLIENT_FQDN_FLAGS_N 0x08 +/* end of original bootp.h */ + +static void rfc1048_print(netdissect_options *, const u_char *); +static void cmu_print(netdissect_options *, const u_char *); +static char *client_fqdn_flags(u_int flags); + +static const struct tok bootp_flag_values[] = { + { 0x8000, "Broadcast" }, + { 0, NULL} +}; + +static const struct tok bootp_op_values[] = { + { BOOTPREQUEST, "Request" }, + { BOOTPREPLY, "Reply" }, + { 0, NULL} +}; /* * Print bootp requests */ void -bootp_print(register const u_char *cp, u_int length, - u_short sport, u_short dport) +bootp_print(netdissect_options *ndo, + register const u_char *cp, u_int length) { register const struct bootp *bp; - static u_char vm_cmu[4] = VM_CMU; - static u_char vm_rfc1048[4] = VM_RFC1048; - - bp = (struct bootp *)cp; - TCHECK(bp->bp_op); - switch (bp->bp_op) { - - case BOOTREQUEST: - /* Usually, a request goes from a client to a server */ - if (sport != IPPORT_BOOTPC || dport != IPPORT_BOOTPS) - printf(" (request)"); - break; - - case BOOTREPLY: - /* Usually, a reply goes from a server to a client */ - if (sport != IPPORT_BOOTPS || dport != IPPORT_BOOTPC) - printf(" (reply)"); - break; - - default: - printf(" bootp-#%d", bp->bp_op); + static const u_char vm_cmu[4] = VM_CMU; + static const u_char vm_rfc1048[4] = VM_RFC1048; + + bp = (const struct bootp *)cp; + ND_TCHECK(bp->bp_op); + + ND_PRINT((ndo, "BOOTP/DHCP, %s", + tok2str(bootp_op_values, "unknown (0x%02x)", bp->bp_op))); + + if (bp->bp_htype == 1 && bp->bp_hlen == 6 && bp->bp_op == BOOTPREQUEST) { + ND_TCHECK2(bp->bp_chaddr[0], 6); + ND_PRINT((ndo, " from %s", etheraddr_string(ndo, bp->bp_chaddr))); } - TCHECK(bp->bp_secs); + ND_PRINT((ndo, ", length %u", length)); + + if (!ndo->ndo_vflag) + return; + + ND_TCHECK(bp->bp_secs); /* The usual hardware address type is 1 (10Mb Ethernet) */ if (bp->bp_htype != 1) - printf(" htype-#%d", bp->bp_htype); + ND_PRINT((ndo, ", htype %d", bp->bp_htype)); /* The usual length for 10Mb Ethernet address is 6 bytes */ if (bp->bp_htype != 1 || bp->bp_hlen != 6) - printf(" hlen:%d", bp->bp_hlen); + ND_PRINT((ndo, ", hlen %d", bp->bp_hlen)); /* Only print interesting fields */ if (bp->bp_hops) - printf(" hops:%d", bp->bp_hops); - if (bp->bp_xid) - printf(" xid:0x%x", (u_int32_t)ntohl(bp->bp_xid)); - if (bp->bp_secs) - printf(" secs:%d", ntohs(bp->bp_secs)); - if (bp->bp_flags) - printf(" flags:0x%x", ntohs(bp->bp_flags)); + ND_PRINT((ndo, ", hops %d", bp->bp_hops)); + if (EXTRACT_32BITS(&bp->bp_xid)) + ND_PRINT((ndo, ", xid 0x%x", EXTRACT_32BITS(&bp->bp_xid))); + if (EXTRACT_16BITS(&bp->bp_secs)) + ND_PRINT((ndo, ", secs %d", EXTRACT_16BITS(&bp->bp_secs))); + + ND_PRINT((ndo, ", Flags [%s]", + bittok2str(bootp_flag_values, "none", EXTRACT_16BITS(&bp->bp_flags)))); + if (ndo->ndo_vflag > 1) + ND_PRINT((ndo, " (0x%04x)", EXTRACT_16BITS(&bp->bp_flags))); /* Client's ip address */ - TCHECK(bp->bp_ciaddr); - if (bp->bp_ciaddr.s_addr) - printf(" C:%s", ipaddr_string(&bp->bp_ciaddr)); + ND_TCHECK(bp->bp_ciaddr); + if (EXTRACT_32BITS(&bp->bp_ciaddr.s_addr)) + ND_PRINT((ndo, "\n\t Client-IP %s", ipaddr_string(ndo, &bp->bp_ciaddr))); /* 'your' ip address (bootp client) */ - TCHECK(bp->bp_yiaddr); - if (bp->bp_yiaddr.s_addr) - printf(" Y:%s", ipaddr_string(&bp->bp_yiaddr)); + ND_TCHECK(bp->bp_yiaddr); + if (EXTRACT_32BITS(&bp->bp_yiaddr.s_addr)) + ND_PRINT((ndo, "\n\t Your-IP %s", ipaddr_string(ndo, &bp->bp_yiaddr))); /* Server's ip address */ - TCHECK(bp->bp_siaddr); - if (bp->bp_siaddr.s_addr) - printf(" S:%s", ipaddr_string(&bp->bp_siaddr)); + ND_TCHECK(bp->bp_siaddr); + if (EXTRACT_32BITS(&bp->bp_siaddr.s_addr)) + ND_PRINT((ndo, "\n\t Server-IP %s", ipaddr_string(ndo, &bp->bp_siaddr))); /* Gateway's ip address */ - TCHECK(bp->bp_giaddr); - if (bp->bp_giaddr.s_addr) - printf(" G:%s", ipaddr_string(&bp->bp_giaddr)); + ND_TCHECK(bp->bp_giaddr); + if (EXTRACT_32BITS(&bp->bp_giaddr.s_addr)) + ND_PRINT((ndo, "\n\t Gateway-IP %s", ipaddr_string(ndo, &bp->bp_giaddr))); /* Client's Ethernet address */ if (bp->bp_htype == 1 && bp->bp_hlen == 6) { - register const struct ether_header *eh; - register const char *e; - - TCHECK2(bp->bp_chaddr[0], 6); - eh = (struct ether_header *)packetp; - if (bp->bp_op == BOOTREQUEST) - e = (const char *)ESRC(eh); - else if (bp->bp_op == BOOTREPLY) - e = (const char *)EDST(eh); - else - e = 0; - if (e == 0 || memcmp((char *)bp->bp_chaddr, e, 6) != 0) - printf(" ether %s", etheraddr_string(bp->bp_chaddr)); + ND_TCHECK2(bp->bp_chaddr[0], 6); + ND_PRINT((ndo, "\n\t Client-Ethernet-Address %s", etheraddr_string(ndo, bp->bp_chaddr))); } - TCHECK2(bp->bp_sname[0], 1); /* check first char only */ + ND_TCHECK2(bp->bp_sname[0], 1); /* check first char only */ if (*bp->bp_sname) { - printf(" sname \""); - if (fn_print(bp->bp_sname, snapend)) { - putchar('"'); - fputs(tstr + 1, stdout); + ND_PRINT((ndo, "\n\t sname \"")); + if (fn_print(ndo, bp->bp_sname, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + ND_PRINT((ndo, "%s", tstr + 1)); return; } - putchar('"'); + ND_PRINT((ndo, "\"")); } - TCHECK2(bp->bp_sname[0], 1); /* check first char only */ + ND_TCHECK2(bp->bp_file[0], 1); /* check first char only */ if (*bp->bp_file) { - printf(" file \""); - if (fn_print(bp->bp_file, snapend)) { - putchar('"'); - fputs(tstr + 1, stdout); + ND_PRINT((ndo, "\n\t file \"")); + if (fn_print(ndo, bp->bp_file, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + ND_PRINT((ndo, "%s", tstr + 1)); return; } - putchar('"'); + ND_PRINT((ndo, "\"")); } /* Decode the vendor buffer */ - TCHECK(bp->bp_vend[0]); - length -= sizeof(*bp) - sizeof(bp->bp_vend); - if (memcmp((char *)bp->bp_vend, (char *)vm_rfc1048, - sizeof(u_int32_t)) == 0) - rfc1048_print(bp->bp_vend, length); - else if (memcmp((char *)bp->bp_vend, (char *)vm_cmu, - sizeof(u_int32_t)) == 0) - cmu_print(bp->bp_vend, length); + ND_TCHECK(bp->bp_vend[0]); + if (memcmp((const char *)bp->bp_vend, vm_rfc1048, + sizeof(uint32_t)) == 0) + rfc1048_print(ndo, bp->bp_vend); + else if (memcmp((const char *)bp->bp_vend, vm_cmu, + sizeof(uint32_t)) == 0) + cmu_print(ndo, bp->bp_vend); else { - u_int32_t ul; + uint32_t ul; - memcpy((char *)&ul, (char *)bp->bp_vend, sizeof(ul)); + ul = EXTRACT_32BITS(&bp->bp_vend); if (ul != 0) - printf("vend-#0x%x", ul); + ND_PRINT((ndo, "\n\t Vendor-#0x%x", ul)); } return; trunc: - fputs(tstr, stdout); + ND_PRINT((ndo, "%s", tstr)); } -/* The first character specifies the format to print */ -static struct tok tag2str[] = { +/* + * The first character specifies the format to print: + * i - ip address (32 bits) + * p - ip address pairs (32 bits + 32 bits) + * l - long (32 bits) + * L - unsigned long (32 bits) + * s - short (16 bits) + * b - period-seperated decimal bytes (variable length) + * x - colon-seperated hex bytes (variable length) + * a - ascii string (variable length) + * B - on/off (8 bits) + * $ - special (explicit code to handle) + */ +static const struct tok tag2str[] = { /* RFC1048 tags */ { TAG_PAD, " PAD" }, - { TAG_SUBNET_MASK, "iSM" }, /* subnet mask (RFC950) */ - { TAG_TIME_OFFSET, "lTZ" }, /* seconds from UTC */ - { TAG_GATEWAY, "iDG" }, /* default gateway */ - { TAG_TIME_SERVER, "iTS" }, /* time servers (RFC868) */ - { TAG_NAME_SERVER, "iIEN" }, /* IEN name servers (IEN116) */ - { TAG_DOMAIN_SERVER, "iNS" }, /* domain name (RFC1035) */ + { TAG_SUBNET_MASK, "iSubnet-Mask" }, /* subnet mask (RFC950) */ + { TAG_TIME_OFFSET, "LTime-Zone" }, /* seconds from UTC */ + { TAG_GATEWAY, "iDefault-Gateway" }, /* default gateway */ + { TAG_TIME_SERVER, "iTime-Server" }, /* time servers (RFC868) */ + { TAG_NAME_SERVER, "iIEN-Name-Server" }, /* IEN name servers (IEN116) */ + { TAG_DOMAIN_SERVER, "iDomain-Name-Server" }, /* domain name (RFC1035) */ { TAG_LOG_SERVER, "iLOG" }, /* MIT log servers */ { TAG_COOKIE_SERVER, "iCS" }, /* cookie servers (RFC865) */ - { TAG_LPR_SERVER, "iLPR" }, /* lpr server (RFC1179) */ + { TAG_LPR_SERVER, "iLPR-Server" }, /* lpr server (RFC1179) */ { TAG_IMPRESS_SERVER, "iIM" }, /* impress servers (Imagen) */ { TAG_RLP_SERVER, "iRL" }, /* resource location (RFC887) */ - { TAG_HOSTNAME, "aHN" }, /* ascii hostname */ + { TAG_HOSTNAME, "aHostname" }, /* ascii hostname */ { TAG_BOOTSIZE, "sBS" }, /* 512 byte blocks */ { TAG_END, " END" }, /* RFC1497 tags */ { TAG_DUMPPATH, "aDP" }, - { TAG_DOMAINNAME, "aDN" }, + { TAG_DOMAINNAME, "aDomain-Name" }, { TAG_SWAP_SERVER, "iSS" }, { TAG_ROOTPATH, "aRP" }, { TAG_EXTPATH, "aEP" }, @@ -214,16 +434,16 @@ static struct tok tag2str[] = { { TAG_PFILTERS, "pPF" }, { TAG_REASS_SIZE, "sRSZ" }, { TAG_DEF_TTL, "bTTL" }, - { TAG_MTU_TIMEOUT, "lMA" }, - { TAG_MTU_TABLE, "sMT" }, + { TAG_MTU_TIMEOUT, "lMTU-Timeout" }, + { TAG_MTU_TABLE, "sMTU-Table" }, { TAG_INT_MTU, "sMTU" }, { TAG_LOCAL_SUBNETS, "BLSN" }, { TAG_BROAD_ADDR, "iBR" }, { TAG_DO_MASK_DISC, "BMD" }, { TAG_SUPPLY_MASK, "BMS" }, - { TAG_DO_RDISC, "BRD" }, + { TAG_DO_RDISC, "BRouter-Discovery" }, { TAG_RTR_SOL_ADDR, "iRSA" }, - { TAG_STATIC_ROUTE, "pSR" }, + { TAG_STATIC_ROUTE, "pStatic-Route" }, { TAG_USE_TRAILERS, "BUT" }, { TAG_ARP_TIMEOUT, "lAT" }, { TAG_ETH_ENCAP, "BIE" }, @@ -233,11 +453,11 @@ static struct tok tag2str[] = { { TAG_NIS_DOMAIN, "aYD" }, { TAG_NIS_SERVERS, "iYS" }, { TAG_NTP_SERVERS, "iNTP" }, - { TAG_VENDOR_OPTS, "bVO" }, - { TAG_NETBIOS_NS, "iWNS" }, + { TAG_VENDOR_OPTS, "bVendor-Option" }, + { TAG_NETBIOS_NS, "iNetbios-Name-Server" }, { TAG_NETBIOS_DDS, "iWDD" }, - { TAG_NETBIOS_NODE, "bWNT" }, - { TAG_NETBIOS_SCOPE, "aWSC" }, + { TAG_NETBIOS_NODE, "$Netbios-Node" }, + { TAG_NETBIOS_SCOPE, "aNetbios-Scope" }, { TAG_XWIN_FS, "iXFS" }, { TAG_XWIN_DM, "iXDM" }, { TAG_NIS_P_DOMAIN, "sN+D" }, @@ -251,97 +471,225 @@ static struct tok tag2str[] = { { TAG_IRC_SERVER, "iIRC" }, { TAG_STREETTALK_SRVR, "iSTS" }, { TAG_STREETTALK_STDA, "iSTDA" }, - { TAG_REQUESTED_IP, "iRQ" }, - { TAG_IP_LEASE, "lLT" }, - { TAG_OPT_OVERLOAD, "bOO" }, + { TAG_REQUESTED_IP, "iRequested-IP" }, + { TAG_IP_LEASE, "lLease-Time" }, + { TAG_OPT_OVERLOAD, "$OO" }, { TAG_TFTP_SERVER, "aTFTP" }, { TAG_BOOTFILENAME, "aBF" }, - { TAG_DHCP_MESSAGE, " DHCP" }, - { TAG_SERVER_ID, "iSID" }, - { TAG_PARM_REQUEST, "bPR" }, + { TAG_DHCP_MESSAGE, " DHCP-Message" }, + { TAG_SERVER_ID, "iServer-ID" }, + { TAG_PARM_REQUEST, "bParameter-Request" }, { TAG_MESSAGE, "aMSG" }, { TAG_MAX_MSG_SIZE, "sMSZ" }, { TAG_RENEWAL_TIME, "lRN" }, { TAG_REBIND_TIME, "lRB" }, - { TAG_VENDOR_CLASS, "bVC" }, - { TAG_CLIENT_ID, "xCID" }, - { 0, NULL } + { TAG_VENDOR_CLASS, "aVendor-Class" }, + { TAG_CLIENT_ID, "$Client-ID" }, +/* RFC 2485 */ + { TAG_OPEN_GROUP_UAP, "aUAP" }, +/* RFC 2563 */ + { TAG_DISABLE_AUTOCONF, "BNOAUTO" }, +/* RFC 2610 */ + { TAG_SLP_DA, "bSLP-DA" }, /*"b" is a little wrong */ + { TAG_SLP_SCOPE, "bSLP-SCOPE" }, /*"b" is a little wrong */ +/* RFC 2937 */ + { TAG_NS_SEARCH, "sNSSEARCH" }, /* XXX 's' */ +/* RFC 3004 - The User Class Option for DHCP */ + { TAG_USER_CLASS, "$User-Class" }, +/* RFC 3011 */ + { TAG_IP4_SUBNET_SELECT, "iSUBNET" }, +/* RFC 3442 */ + { TAG_CLASSLESS_STATIC_RT, "$Classless-Static-Route" }, + { TAG_CLASSLESS_STA_RT_MS, "$Classless-Static-Route-Microsoft" }, +/* RFC 5859 - TFTP Server Address Option for DHCPv4 */ + { TAG_TFTP_SERVER_ADDRESS, "iTFTP-Server-Address" }, +/* http://www.iana.org/assignments/bootp-dhcp-extensions/index.htm */ + { TAG_SLP_NAMING_AUTH, "aSLP-NA" }, + { TAG_CLIENT_FQDN, "$FQDN" }, + { TAG_AGENT_CIRCUIT, "$Agent-Information" }, + { TAG_AGENT_REMOTE, "bARMT" }, + { TAG_AGENT_MASK, "bAMSK" }, + { TAG_TZ_STRING, "aTZSTR" }, + { TAG_FQDN_OPTION, "bFQDNS" }, /* XXX 'b' */ + { TAG_AUTH, "bAUTH" }, /* XXX 'b' */ + { TAG_VINES_SERVERS, "iVINES" }, + { TAG_SERVER_RANK, "sRANK" }, + { TAG_CLIENT_ARCH, "sARCH" }, + { TAG_CLIENT_NDI, "bNDI" }, /* XXX 'b' */ + { TAG_CLIENT_GUID, "bGUID" }, /* XXX 'b' */ + { TAG_LDAP_URL, "aLDAP" }, + { TAG_6OVER4, "i6o4" }, + { TAG_PRINTER_NAME, "aPRTR" }, + { TAG_MDHCP_SERVER, "bMDHCP" }, /* XXX 'b' */ + { TAG_IPX_COMPAT, "bIPX" }, /* XXX 'b' */ + { TAG_NETINFO_PARENT, "iNI" }, + { TAG_NETINFO_PARENT_TAG, "aNITAG" }, + { TAG_URL, "aURL" }, + { TAG_FAILOVER, "bFAIL" }, /* XXX 'b' */ + { 0, NULL } +}; +/* 2-byte extended tags */ +static const struct tok xtag2str[] = { + { 0, NULL } +}; + +/* DHCP "options overload" types */ +static const struct tok oo2str[] = { + { 1, "file" }, + { 2, "sname" }, + { 3, "file+sname" }, + { 0, NULL } +}; + +/* NETBIOS over TCP/IP node type options */ +static const struct tok nbo2str[] = { + { 0x1, "b-node" }, + { 0x2, "p-node" }, + { 0x4, "m-node" }, + { 0x8, "h-node" }, + { 0, NULL } +}; + +/* ARP Hardware types, for Client-ID option */ +static const struct tok arp2str[] = { + { 0x1, "ether" }, + { 0x6, "ieee802" }, + { 0x7, "arcnet" }, + { 0xf, "frelay" }, + { 0x17, "strip" }, + { 0x18, "ieee1394" }, + { 0, NULL } }; +static const struct tok dhcp_msg_values[] = { + { DHCPDISCOVER, "Discover" }, + { DHCPOFFER, "Offer" }, + { DHCPREQUEST, "Request" }, + { DHCPDECLINE, "Decline" }, + { DHCPACK, "ACK" }, + { DHCPNAK, "NACK" }, + { DHCPRELEASE, "Release" }, + { DHCPINFORM, "Inform" }, + { 0, NULL } +}; + +#define AGENT_SUBOPTION_CIRCUIT_ID 1 /* RFC 3046 */ +#define AGENT_SUBOPTION_REMOTE_ID 2 /* RFC 3046 */ +#define AGENT_SUBOPTION_SUBSCRIBER_ID 6 /* RFC 3993 */ +static const struct tok agent_suboption_values[] = { + { AGENT_SUBOPTION_CIRCUIT_ID, "Circuit-ID" }, + { AGENT_SUBOPTION_REMOTE_ID, "Remote-ID" }, + { AGENT_SUBOPTION_SUBSCRIBER_ID, "Subscriber-ID" }, + { 0, NULL } +}; + + static void -rfc1048_print(register const u_char *bp, register u_int length) +rfc1048_print(netdissect_options *ndo, + register const u_char *bp) { - register u_char tag; - register u_int len, size; + register uint16_t tag; + register u_int len; register const char *cp; register char c; - int first; - u_int32_t ul; - u_short us; + int first, idx; + uint32_t ul; + uint16_t us; + uint8_t uc, subopt, suboptlen; - printf(" vend-rfc1048"); + ND_PRINT((ndo, "\n\t Vendor-rfc1048 Extensions")); /* Step over magic cookie */ + ND_PRINT((ndo, "\n\t Magic Cookie 0x%08x", EXTRACT_32BITS(bp))); bp += sizeof(int32_t); /* Loop while we there is a tag left in the buffer */ - while (bp + 1 < snapend) { + while (ND_TTEST2(*bp, 1)) { tag = *bp++; - if (tag == TAG_PAD) + if (tag == TAG_PAD && ndo->ndo_vflag < 3) continue; - if (tag == TAG_END) + if (tag == TAG_END && ndo->ndo_vflag < 3) return; - cp = tok2str(tag2str, "?T%d", tag); + if (tag == TAG_EXTENDED_OPTION) { + ND_TCHECK2(*(bp + 1), 2); + tag = EXTRACT_16BITS(bp + 1); + /* XXX we don't know yet if the IANA will + * preclude overlap of 1-byte and 2-byte spaces. + * If not, we need to offset tag after this step. + */ + cp = tok2str(xtag2str, "?xT%u", tag); + } else + cp = tok2str(tag2str, "?T%u", tag); c = *cp++; - printf(" %s:", cp); - /* Get the length; check for truncation */ - if (bp + 1 >= snapend) { - fputs(tstr, stdout); - return; + if (tag == TAG_PAD || tag == TAG_END) + len = 0; + else { + /* Get the length; check for truncation */ + ND_TCHECK2(*bp, 1); + len = *bp++; + } + + ND_PRINT((ndo, "\n\t %s Option %u, length %u%s", cp, tag, len, + len > 0 ? ": " : "")); + + if (tag == TAG_PAD && ndo->ndo_vflag > 2) { + u_int ntag = 1; + while (ND_TTEST2(*bp, 1) && *bp == TAG_PAD) { + bp++; + ntag++; + } + if (ntag > 1) + ND_PRINT((ndo, ", occurs %u", ntag)); } - len = *bp++; - if (bp + len >= snapend) { - fputs(tstr, stdout); + + if (!ND_TTEST2(*bp, len)) { + ND_PRINT((ndo, "[|rfc1048 %u]", len)); return; } if (tag == TAG_DHCP_MESSAGE && len == 1) { - c = *bp++; - switch (c) { - case DHCPDISCOVER: printf("DISCOVER"); break; - case DHCPOFFER: printf("OFFER"); break; - case DHCPREQUEST: printf("REQUEST"); break; - case DHCPDECLINE: printf("DECLINE"); break; - case DHCPACK: printf("ACK"); break; - case DHCPNAK: printf("NACK"); break; - case DHCPRELEASE: printf("RELEASE"); break; - case DHCPINFORM: printf("INFORM"); break; - default: printf("%u", c); break; - } + uc = *bp++; + ND_PRINT((ndo, "%s", tok2str(dhcp_msg_values, "Unknown (%u)", uc))); continue; } if (tag == TAG_PARM_REQUEST) { - first = 1; + idx = 0; while (len-- > 0) { - c = *bp++; - cp = tok2str(tag2str, "?%d", c); + uc = *bp++; + cp = tok2str(tag2str, "?Option %u", uc); + if (idx % 4 == 0) + ND_PRINT((ndo, "\n\t ")); + else + ND_PRINT((ndo, ", ")); + ND_PRINT((ndo, "%s", cp + 1)); + idx++; + } + continue; + } + + if (tag == TAG_EXTENDED_REQUEST) { + first = 1; + while (len > 1) { + len -= 2; + us = EXTRACT_16BITS(bp); + bp += 2; + cp = tok2str(xtag2str, "?xT%u", us); if (!first) - putchar('+'); - printf("%s", cp + 1); + ND_PRINT((ndo, "+")); + ND_PRINT((ndo, "%s", cp + 1)); first = 0; } continue; } /* Print data */ - size = len; if (c == '?') { /* Base default formats for unknown tags on data size */ - if (size & 1) + if (len & 1) c = 'b'; - else if (size & 2) + else if (len & 2) c = 's'; else c = 'l'; @@ -351,77 +699,84 @@ rfc1048_print(register const u_char *bp, register u_int length) case 'a': /* ascii strings */ - putchar('"'); - (void)fn_printn(bp, size, NULL); - putchar('"'); - bp += size; - size = 0; + ND_PRINT((ndo, "\"")); + if (fn_printn(ndo, bp, len, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + goto trunc; + } + ND_PRINT((ndo, "\"")); + bp += len; + len = 0; break; case 'i': case 'l': + case 'L': /* ip addresses/32-bit words */ - while (size >= sizeof(ul)) { + while (len >= sizeof(ul)) { if (!first) - putchar(','); - memcpy((char *)&ul, (char *)bp, sizeof(ul)); - if (c == 'i') - printf("%s", ipaddr_string(&ul)); + ND_PRINT((ndo, ",")); + ul = EXTRACT_32BITS(bp); + if (c == 'i') { + ul = htonl(ul); + ND_PRINT((ndo, "%s", ipaddr_string(ndo, &ul))); + } else if (c == 'L') + ND_PRINT((ndo, "%d", ul)); else - printf("%u", ul); + ND_PRINT((ndo, "%u", ul)); bp += sizeof(ul); - size -= sizeof(ul); + len -= sizeof(ul); first = 0; } break; case 'p': /* IP address pairs */ - while (size >= 2*sizeof(ul)) { + while (len >= 2*sizeof(ul)) { if (!first) - putchar(','); - memcpy((char *)&ul, (char *)bp, sizeof(ul)); - printf("(%s:", ipaddr_string(&ul)); + ND_PRINT((ndo, ",")); + memcpy((char *)&ul, (const char *)bp, sizeof(ul)); + ND_PRINT((ndo, "(%s:", ipaddr_string(ndo, &ul))); bp += sizeof(ul); - memcpy((char *)&ul, (char *)bp, sizeof(ul)); - printf("%s)", ipaddr_string(&ul)); + memcpy((char *)&ul, (const char *)bp, sizeof(ul)); + ND_PRINT((ndo, "%s)", ipaddr_string(ndo, &ul))); bp += sizeof(ul); - size -= 2*sizeof(ul); + len -= 2*sizeof(ul); first = 0; } break; case 's': /* shorts */ - while (size >= sizeof(us)) { + while (len >= sizeof(us)) { if (!first) - putchar(','); - memcpy((char *)&us, (char *)bp, sizeof(us)); - printf("%d", us); + ND_PRINT((ndo, ",")); + us = EXTRACT_16BITS(bp); + ND_PRINT((ndo, "%u", us)); bp += sizeof(us); - size -= sizeof(us); + len -= sizeof(us); first = 0; } break; case 'B': /* boolean */ - while (size > 0) { + while (len > 0) { if (!first) - putchar(','); + ND_PRINT((ndo, ",")); switch (*bp) { case 0: - putchar('N'); + ND_PRINT((ndo, "N")); break; case 1: - putchar('Y'); + ND_PRINT((ndo, "Y")); break; default: - printf("%d?", *bp); + ND_PRINT((ndo, "%u?", *bp)); break; } ++bp; - --size; + --len; first = 0; } break; @@ -430,39 +785,273 @@ rfc1048_print(register const u_char *bp, register u_int length) case 'x': default: /* Bytes */ - while (size > 0) { + while (len > 0) { if (!first) - putchar (c == 'x' ? ':' : '.'); - printf (c == 'x' ? "%02x" : "%d", *bp); + ND_PRINT((ndo, c == 'x' ? ":" : ".")); + if (c == 'x') + ND_PRINT((ndo, "%02x", *bp)); + else + ND_PRINT((ndo, "%u", *bp)); ++bp; - --size; + --len; first = 0; } break; + + case '$': + /* Guys we can't handle with one of the usual cases */ + switch (tag) { + + case TAG_NETBIOS_NODE: + /* this option should be at least 1 byte long */ + if (len < 1) { + ND_PRINT((ndo, "ERROR: length < 1 bytes")); + break; + } + tag = *bp++; + --len; + ND_PRINT((ndo, "%s", tok2str(nbo2str, NULL, tag))); + break; + + case TAG_OPT_OVERLOAD: + /* this option should be at least 1 byte long */ + if (len < 1) { + ND_PRINT((ndo, "ERROR: length < 1 bytes")); + break; + } + tag = *bp++; + --len; + ND_PRINT((ndo, "%s", tok2str(oo2str, NULL, tag))); + break; + + case TAG_CLIENT_FQDN: + /* this option should be at least 3 bytes long */ + if (len < 3) { + ND_PRINT((ndo, "ERROR: length < 3 bytes")); + bp += len; + len = 0; + break; + } + if (*bp) + ND_PRINT((ndo, "[%s] ", client_fqdn_flags(*bp))); + bp++; + if (*bp || *(bp+1)) + ND_PRINT((ndo, "%u/%u ", *bp, *(bp+1))); + bp += 2; + ND_PRINT((ndo, "\"")); + if (fn_printn(ndo, bp, len - 3, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + goto trunc; + } + ND_PRINT((ndo, "\"")); + bp += len - 3; + len = 0; + break; + + case TAG_CLIENT_ID: + { + int type; + + /* this option should be at least 1 byte long */ + if (len < 1) { + ND_PRINT((ndo, "ERROR: length < 1 bytes")); + break; + } + type = *bp++; + len--; + if (type == 0) { + ND_PRINT((ndo, "\"")); + if (fn_printn(ndo, bp, len, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + goto trunc; + } + ND_PRINT((ndo, "\"")); + bp += len; + len = 0; + break; + } else { + ND_PRINT((ndo, "%s ", tok2str(arp2str, "hardware-type %u,", type))); + while (len > 0) { + if (!first) + ND_PRINT((ndo, ":")); + ND_PRINT((ndo, "%02x", *bp)); + ++bp; + --len; + first = 0; + } + } + break; + } + + case TAG_AGENT_CIRCUIT: + while (len >= 2) { + subopt = *bp++; + suboptlen = *bp++; + len -= 2; + if (suboptlen > len) { + ND_PRINT((ndo, "\n\t %s SubOption %u, length %u: length goes past end of option", + tok2str(agent_suboption_values, "Unknown", subopt), + subopt, + suboptlen)); + bp += len; + len = 0; + break; + } + ND_PRINT((ndo, "\n\t %s SubOption %u, length %u: ", + tok2str(agent_suboption_values, "Unknown", subopt), + subopt, + suboptlen)); + switch (subopt) { + + case AGENT_SUBOPTION_CIRCUIT_ID: /* fall through */ + case AGENT_SUBOPTION_REMOTE_ID: + case AGENT_SUBOPTION_SUBSCRIBER_ID: + if (fn_printn(ndo, bp, suboptlen, ndo->ndo_snapend)) + goto trunc; + break; + + default: + print_unknown_data(ndo, bp, "\n\t\t", suboptlen); + } + + len -= suboptlen; + bp += suboptlen; + } + break; + + case TAG_CLASSLESS_STATIC_RT: + case TAG_CLASSLESS_STA_RT_MS: + { + u_int mask_width, significant_octets, i; + + /* this option should be at least 5 bytes long */ + if (len < 5) { + ND_PRINT((ndo, "ERROR: length < 5 bytes")); + bp += len; + len = 0; + break; + } + while (len > 0) { + if (!first) + ND_PRINT((ndo, ",")); + mask_width = *bp++; + len--; + /* mask_width <= 32 */ + if (mask_width > 32) { + ND_PRINT((ndo, "[ERROR: Mask width (%d) > 32]", mask_width)); + bp += len; + len = 0; + break; + } + significant_octets = (mask_width + 7) / 8; + /* significant octets + router(4) */ + if (len < significant_octets + 4) { + ND_PRINT((ndo, "[ERROR: Remaining length (%u) < %u bytes]", len, significant_octets + 4)); + bp += len; + len = 0; + break; + } + ND_PRINT((ndo, "(")); + if (mask_width == 0) + ND_PRINT((ndo, "default")); + else { + for (i = 0; i < significant_octets ; i++) { + if (i > 0) + ND_PRINT((ndo, ".")); + ND_PRINT((ndo, "%d", *bp++)); + } + for (i = significant_octets ; i < 4 ; i++) + ND_PRINT((ndo, ".0")); + ND_PRINT((ndo, "/%d", mask_width)); + } + memcpy((char *)&ul, (const char *)bp, sizeof(ul)); + ND_PRINT((ndo, ":%s)", ipaddr_string(ndo, &ul))); + bp += sizeof(ul); + len -= (significant_octets + 4); + first = 0; + } + break; + } + + case TAG_USER_CLASS: + { + u_int suboptnumber = 1; + + first = 1; + if (len < 2) { + ND_PRINT((ndo, "ERROR: length < 2 bytes")); + bp += len; + len = 0; + break; + } + while (len > 0) { + suboptlen = *bp++; + len--; + ND_PRINT((ndo, "\n\t ")); + ND_PRINT((ndo, "instance#%u: ", suboptnumber)); + if (suboptlen == 0) { + ND_PRINT((ndo, "ERROR: suboption length must be non-zero")); + bp += len; + len = 0; + break; + } + if (len < suboptlen) { + ND_PRINT((ndo, "ERROR: invalid option")); + bp += len; + len = 0; + break; + } + ND_PRINT((ndo, "\"")); + if (fn_printn(ndo, bp, suboptlen, ndo->ndo_snapend)) { + ND_PRINT((ndo, "\"")); + goto trunc; + } + ND_PRINT((ndo, "\"")); + ND_PRINT((ndo, ", length %d", suboptlen)); + suboptnumber++; + len -= suboptlen; + bp += suboptlen; + } + break; + } + + default: + ND_PRINT((ndo, "[unknown special tag %u, size %u]", + tag, len)); + bp += len; + len = 0; + break; + } + break; } /* Data left over? */ - if (size) - printf("[len %d]", len); + if (len) { + ND_PRINT((ndo, "\n\t trailing data length %u", len)); + bp += len; + } } + return; +trunc: + ND_PRINT((ndo, "|[rfc1048]")); } static void -cmu_print(register const u_char *bp, register u_int length) +cmu_print(netdissect_options *ndo, + register const u_char *bp) { register const struct cmu_vend *cmu; - char *fmt = " %s:%s"; -#define PRINTCMUADDR(m, s) { TCHECK(cmu->m); \ +#define PRINTCMUADDR(m, s) { ND_TCHECK(cmu->m); \ if (cmu->m.s_addr != 0) \ - printf(fmt, s, ipaddr_string(&cmu->m.s_addr)); } + ND_PRINT((ndo, " %s:%s", s, ipaddr_string(ndo, &cmu->m.s_addr))); } - printf(" vend-cmu"); - cmu = (struct cmu_vend *)bp; + ND_PRINT((ndo, " vend-cmu")); + cmu = (const struct cmu_vend *)bp; /* Only print if there are unknown bits */ - TCHECK(cmu->v_flags); + ND_TCHECK(cmu->v_flags); if ((cmu->v_flags & ~(VF_SMASK)) != 0) - printf(" F:0x%x", cmu->v_flags); + ND_PRINT((ndo, " F:0x%x", cmu->v_flags)); PRINTCMUADDR(v_dgate, "DG"); PRINTCMUADDR(v_smask, cmu->v_flags & VF_SMASK ? "SM" : "SM*"); PRINTCMUADDR(v_dns1, "NS1"); @@ -474,6 +1063,25 @@ cmu_print(register const u_char *bp, register u_int length) return; trunc: - fputs(tstr, stdout); + ND_PRINT((ndo, "%s", tstr)); #undef PRINTCMUADDR } + +static char * +client_fqdn_flags(u_int flags) +{ + static char buf[8+1]; + int i = 0; + + if (flags & CLIENT_FQDN_FLAGS_S) + buf[i++] = 'S'; + if (flags & CLIENT_FQDN_FLAGS_O) + buf[i++] = 'O'; + if (flags & CLIENT_FQDN_FLAGS_E) + buf[i++] = 'E'; + if (flags & CLIENT_FQDN_FLAGS_N) + buf[i++] = 'N'; + buf[i] = '\0'; + + return buf; +}