/* vi: set sw=4 ts=4: */ /* * Rewrite by Russ Dill July 2001 * * Licensed under GPLv2, see file LICENSE in this source tree. */ #include "common.h" #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 unsigned dhcp_verbose; #endif const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; #if ENABLE_UDHCPC || ENABLE_UDHCPD /* Supported options are easily added here. * See RFC2132 for more options. * OPTION_REQ: these options are requested by udhcpc (unless -o). */ const struct dhcp_optflag dhcp_optflags[] = { /* flags code */ { OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */ { OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */ { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */ // { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */ // { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */ { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */ // { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */ // { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */ { OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */ { OPTION_STRING_HOST | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */ { OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */ { OPTION_STRING_HOST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */ { OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */ { OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */ { OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */ { OPTION_U16 , 0x1a }, /* DHCP_MTU */ //TODO: why do we request DHCP_BROADCAST? Can't we assume that //in the unlikely case it is different from typical N.N.255.255, //server would let us know anyway? { OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */ { OPTION_IP_PAIR | OPTION_LIST , 0x21 }, /* DHCP_ROUTES */ { OPTION_STRING_HOST , 0x28 }, /* DHCP_NIS_DOMAIN */ { OPTION_IP | OPTION_LIST , 0x29 }, /* DHCP_NIS_SERVER */ { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */ { OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */ { OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */ { OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */ { OPTION_STRING , 0x38 }, /* DHCP_ERR_MESSAGE */ //TODO: must be combined with 'sname' and 'file' handling: { OPTION_STRING_HOST , 0x42 }, /* DHCP_TFTP_SERVER_NAME */ { OPTION_STRING , 0x43 }, /* DHCP_BOOT_FILE */ //TODO: not a string, but a set of LASCII strings: // { OPTION_STRING , 0x4D }, /* DHCP_USER_CLASS */ #if ENABLE_FEATURE_UDHCP_RFC3397 { OPTION_DNS_STRING | OPTION_LIST , 0x77 }, /* DHCP_DOMAIN_SEARCH */ { OPTION_SIP_SERVERS , 0x78 }, /* DHCP_SIP_SERVERS */ #endif { OPTION_STATIC_ROUTES | OPTION_LIST , 0x79 }, /* DHCP_STATIC_ROUTES */ #if ENABLE_FEATURE_UDHCP_8021Q { OPTION_U16 , 0x84 }, /* DHCP_VLAN_ID */ { OPTION_U8 , 0x85 }, /* DHCP_VLAN_PRIORITY */ #endif { OPTION_STRING , 0xd1 }, /* DHCP_PXE_CONF_FILE */ { OPTION_STRING , 0xd2 }, /* DHCP_PXE_PATH_PREFIX */ { OPTION_6RD , 0xd4 }, /* DHCP_6RD */ { OPTION_STATIC_ROUTES | OPTION_LIST , 0xf9 }, /* DHCP_MS_STATIC_ROUTES */ { OPTION_STRING , 0xfc }, /* DHCP_WPAD */ /* Options below have no match in dhcp_option_strings[], * are not passed to dhcpc scripts, and cannot be specified * with "option XXX YYY" syntax in dhcpd config file. * These entries are only used internally by udhcp[cd] * to correctly encode options into packets. */ { OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */ { OPTION_U8 , 0x35 }, /* DHCP_MESSAGE_TYPE */ { OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */ //looks like these opts will work just fine even without these defs: // { OPTION_STRING , 0x3c }, /* DHCP_VENDOR */ // /* not really a string: */ // { OPTION_STRING , 0x3d }, /* DHCP_CLIENT_ID */ { 0, 0 } /* zeroed terminating entry */ }; /* Used for converting options from incoming packets to env variables * for udhcpc script, and for setting options for udhcpd via * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file. */ /* Must match dhcp_optflags[] order */ const char dhcp_option_strings[] ALIGN1 = "subnet" "\0" /* DHCP_SUBNET */ "timezone" "\0" /* DHCP_TIME_OFFSET */ "router" "\0" /* DHCP_ROUTER */ // "timesrv" "\0" /* DHCP_TIME_SERVER */ // "namesrv" "\0" /* DHCP_NAME_SERVER */ "dns" "\0" /* DHCP_DNS_SERVER */ // "logsrv" "\0" /* DHCP_LOG_SERVER */ // "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */ "lprsrv" "\0" /* DHCP_LPR_SERVER */ "hostname" "\0" /* DHCP_HOST_NAME */ "bootsize" "\0" /* DHCP_BOOT_SIZE */ "domain" "\0" /* DHCP_DOMAIN_NAME */ "swapsrv" "\0" /* DHCP_SWAP_SERVER */ "rootpath" "\0" /* DHCP_ROOT_PATH */ "ipttl" "\0" /* DHCP_IP_TTL */ "mtu" "\0" /* DHCP_MTU */ "broadcast" "\0" /* DHCP_BROADCAST */ "routes" "\0" /* DHCP_ROUTES */ "nisdomain" "\0" /* DHCP_NIS_DOMAIN */ "nissrv" "\0" /* DHCP_NIS_SERVER */ "ntpsrv" "\0" /* DHCP_NTP_SERVER */ "wins" "\0" /* DHCP_WINS_SERVER */ "lease" "\0" /* DHCP_LEASE_TIME */ "serverid" "\0" /* DHCP_SERVER_ID */ "message" "\0" /* DHCP_ERR_MESSAGE */ "tftp" "\0" /* DHCP_TFTP_SERVER_NAME */ "bootfile" "\0" /* DHCP_BOOT_FILE */ // "userclass" "\0" /* DHCP_USER_CLASS */ #if ENABLE_FEATURE_UDHCP_RFC3397 "search" "\0" /* DHCP_DOMAIN_SEARCH */ // doesn't work in udhcpd.conf since OPTION_SIP_SERVERS // is not handled yet by "string->option" conversion code: "sipsrv" "\0" /* DHCP_SIP_SERVERS */ #endif "staticroutes" "\0"/* DHCP_STATIC_ROUTES */ #if ENABLE_FEATURE_UDHCP_8021Q "vlanid" "\0" /* DHCP_VLAN_ID */ "vlanpriority" "\0"/* DHCP_VLAN_PRIORITY */ #endif "pxeconffile" "\0" /* DHCP_PXE_CONF_FILE */ "pxepathprefix" "\0" /* DHCP_PXE_PATH_PREFIX */ "ip6rd" "\0" /* DHCP_6RD */ "msstaticroutes""\0"/* DHCP_MS_STATIC_ROUTES */ "wpad" "\0" /* DHCP_WPAD */ ; #endif /* Lengths of the option types in binary form. * Used by: * udhcp_str2optset: to determine how many bytes to allocate. * xmalloc_optname_optval: to estimate string length * from binary option length: (option[LEN] / dhcp_option_lengths[opt_type]) * is the number of elements, multiply it by one element's string width * (len_of_option_as_string[opt_type]) and you know how wide string you need. */ const uint8_t dhcp_option_lengths[] ALIGN1 = { [OPTION_IP] = 4, [OPTION_IP_PAIR] = 8, // [OPTION_BOOLEAN] = 1, [OPTION_STRING] = 1, /* ignored by udhcp_str2optset */ [OPTION_STRING_HOST] = 1, /* ignored by udhcp_str2optset */ #if ENABLE_FEATURE_UDHCP_RFC3397 [OPTION_DNS_STRING] = 1, /* ignored by both udhcp_str2optset and xmalloc_optname_optval */ [OPTION_SIP_SERVERS] = 1, #endif [OPTION_U8] = 1, [OPTION_U16] = 2, // [OPTION_S16] = 2, [OPTION_U32] = 4, [OPTION_S32] = 4, /* Just like OPTION_STRING, we use minimum length here */ [OPTION_STATIC_ROUTES] = 5, [OPTION_6RD] = 12, /* ignored by udhcp_str2optset */ /* The above value was chosen as follows: * len_of_option_as_string[] for this option is >60: it's a string of the form * "32 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 ". * Each additional ipv4 address takes 4 bytes in binary option and appends * another "255.255.255.255 " 16-byte string. We can set [OPTION_6RD] = 4 * but this severely overestimates string length: instead of 16 bytes, * it adds >60 for every 4 bytes in binary option. * We cheat and declare here that option is in units of 12 bytes. * This adds more than 60 bytes for every three ipv4 addresses - more than enough. * (Even 16 instead of 12 should work, but let's be paranoid). */ }; #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2 static void log_option(const char *pfx, const uint8_t *opt) { if (dhcp_verbose >= 2) { char buf[256 * 2 + 2]; *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0'; bb_error_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf); } } #else # define log_option(pfx, opt) ((void)0) #endif unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings) { int n = index_in_strings(option_strings, name); if (n >= 0) return n; { char *buf, *d; const char *s; s = option_strings; while (*s) s += strlen(s) + 1; d = buf = xzalloc(s - option_strings); s = option_strings; while (!(*s == '\0' && s[1] == '\0')) { *d++ = (*s == '\0' ? ' ' : *s); s++; } bb_error_msg_and_die("unknown option '%s', known options: %s", name, buf); } } /* Get an option with bounds checking (warning, result is not aligned) */ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code) { uint8_t *optionptr; int len; int rem; int overload = 0; enum { FILE_FIELD101 = FILE_FIELD * 0x101, SNAME_FIELD101 = SNAME_FIELD * 0x101, }; /* option bytes: [code][len][data1][data2]..[dataLEN] */ optionptr = packet->options; rem = sizeof(packet->options); while (1) { if (rem <= 0) { complain: bb_error_msg("bad packet, malformed option field"); return NULL; } /* DHCP_PADDING and DHCP_END have no [len] byte */ if (optionptr[OPT_CODE] == DHCP_PADDING) { rem--; optionptr++; continue; } if (optionptr[OPT_CODE] == DHCP_END) { if ((overload & FILE_FIELD101) == FILE_FIELD) { /* can use packet->file, and didn't look at it yet */ overload |= FILE_FIELD101; /* "we looked at it" */ optionptr = packet->file; rem = sizeof(packet->file); continue; } if ((overload & SNAME_FIELD101) == SNAME_FIELD) { /* can use packet->sname, and didn't look at it yet */ overload |= SNAME_FIELD101; /* "we looked at it" */ optionptr = packet->sname; rem = sizeof(packet->sname); continue; } break; } if (rem <= OPT_LEN) goto complain; /* complain and return NULL */ len = 2 + optionptr[OPT_LEN]; rem -= len; if (rem < 0) goto complain; /* complain and return NULL */ if (optionptr[OPT_CODE] == code) { log_option("option found", optionptr); return optionptr + OPT_DATA; } if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) { if (len >= 3) overload |= optionptr[OPT_DATA]; /* fall through */ } optionptr += len; } /* log3 because udhcpc uses it a lot - very noisy */ log3("option 0x%02x not found", code); return NULL; } /* Return the position of the 'end' option (no bounds checking) */ int FAST_FUNC udhcp_end_option(uint8_t *optionptr) { int i = 0; while (optionptr[i] != DHCP_END) { if (optionptr[i] != DHCP_PADDING) i += optionptr[i + OPT_LEN] + OPT_DATA-1; i++; } return i; } /* Add an option (supplied in binary form) to the options. * Option format: [code][len][data1][data2]..[dataLEN] */ void FAST_FUNC udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) { unsigned len; uint8_t *optionptr = packet->options; unsigned end = udhcp_end_option(optionptr); len = OPT_DATA + addopt[OPT_LEN]; /* end position + (option code/length + addopt length) + end option */ if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE) { //TODO: learn how to use overflow option if we exhaust packet->options[] bb_error_msg("option 0x%02x did not fit into the packet", addopt[OPT_CODE]); return; } log_option("adding option", addopt); memcpy(optionptr + end, addopt, len); optionptr[end + len] = DHCP_END; } #if ENABLE_UDHCPC || ENABLE_UDHCPD /* Add an one to four byte option to a packet */ void FAST_FUNC udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) { const struct dhcp_optflag *dh; for (dh = dhcp_optflags; dh->code; dh++) { if (dh->code == code) { uint8_t option[6], len; option[OPT_CODE] = code; len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK]; option[OPT_LEN] = len; if (BB_BIG_ENDIAN) data <<= 8 * (4 - len); /* Assignment is unaligned! */ move_to_unaligned32(&option[OPT_DATA], data); udhcp_add_binary_option(packet, option); return; } } bb_error_msg("can't add option 0x%02x", code); } #endif /* Find option 'code' in opt_list */ struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code) { while (opt_list && opt_list->data[OPT_CODE] < code) opt_list = opt_list->next; if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list; return NULL; } /* Parse string to IP in network order */ int FAST_FUNC udhcp_str2nip(const char *str, void *arg) { len_and_sockaddr *lsa; lsa = host_and_af2sockaddr(str, 0, AF_INET); if (!lsa) return 0; /* arg maybe unaligned */ move_to_unaligned32((uint32_t*)arg, lsa->u.sin.sin_addr.s_addr); free(lsa); return 1; } /* udhcp_str2optset: * Parse string option representation to binary form and add it to opt_list. * Called to parse "udhcpc -x OPTNAME:OPTVAL" * and to parse udhcpd.conf's "opt OPTNAME OPTVAL" directives. */ /* helper: add an option to the opt_list */ static NOINLINE void attach_option( struct option_set **opt_list, const struct dhcp_optflag *optflag, char *buffer, int length) { struct option_set *existing; char *allocated = NULL; if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_BIN) { const char *end; allocated = xstrdup(buffer); /* more than enough */ end = hex2bin(allocated, buffer, 255); if (errno) bb_error_msg_and_die("malformed hex string '%s'", buffer); length = end - allocated; } #if ENABLE_FEATURE_UDHCP_RFC3397 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) { /* reuse buffer and length for RFC1035-formatted string */ allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length); } #endif existing = udhcp_find_option(*opt_list, optflag->code); if (!existing) { struct option_set *new, **curr; /* make a new option */ log2("attaching option %02x to list", optflag->code); new = xmalloc(sizeof(*new)); new->data = xmalloc(length + OPT_DATA); new->data[OPT_CODE] = optflag->code; new->data[OPT_LEN] = length; memcpy(new->data + OPT_DATA, (allocated ? allocated : buffer), length); curr = opt_list; while (*curr && (*curr)->data[OPT_CODE] < optflag->code) curr = &(*curr)->next; new->next = *curr; *curr = new; goto ret; } if (optflag->flags & OPTION_LIST) { unsigned old_len; /* add it to an existing option */ log2("attaching option %02x to existing member of list", optflag->code); old_len = existing->data[OPT_LEN]; if (old_len + length < 255) { /* actually 255 is ok too, but adding a space can overlow it */ existing->data = xrealloc(existing->data, OPT_DATA + 1 + old_len + length); if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING || (optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING_HOST ) { /* add space separator between STRING options in a list */ existing->data[OPT_DATA + old_len] = ' '; old_len++; } memcpy(existing->data + OPT_DATA + old_len, (allocated ? allocated : buffer), length); existing->data[OPT_LEN] = old_len + length; } /* else, ignore the data, we could put this in a second option in the future */ } /* else, ignore the new data */ ret: free(allocated); } int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg, const struct dhcp_optflag *optflags, const char *option_strings) { struct option_set **opt_list = arg; char *opt; char *str; const struct dhcp_optflag *optflag; struct dhcp_optflag userdef_optflag; unsigned optcode; int retval; /* IP_PAIR needs 8 bytes, STATIC_ROUTES needs 9 max */ char buffer[9] ALIGNED(4); uint16_t *result_u16 = (uint16_t *) buffer; uint32_t *result_u32 = (uint32_t *) buffer; /* Cheat, the only *const* str possible is "" */ str = (char *) const_str; opt = strtok(str, " \t=:"); if (!opt) return 0; optcode = bb_strtou(opt, NULL, 0); if (!errno && optcode < 255) { /* Raw (numeric) option code. * Initially assume binary (hex-str), but if "str" or 'str' * is seen later, switch to STRING. */ userdef_optflag.flags = OPTION_BIN; userdef_optflag.code = optcode; optflag = &userdef_optflag; } else { optflag = &optflags[udhcp_option_idx(opt, option_strings)]; } /* Loop to handle OPTION_LIST case, else execute just once */ retval = 0; do { int length; char *val; if (optflag->flags == OPTION_BIN) { val = strtok(NULL, ""); /* do not split "'q w e'" */ trim(val); } else val = strtok(NULL, ", \t"); if (!val) break; length = dhcp_option_lengths[optflag->flags & OPTION_TYPE_MASK]; retval = 0; opt = buffer; /* new meaning for variable opt */ switch (optflag->flags & OPTION_TYPE_MASK) { case OPTION_IP: retval = udhcp_str2nip(val, buffer); break; case OPTION_IP_PAIR: retval = udhcp_str2nip(val, buffer); val = strtok(NULL, ", \t/-"); if (!val) retval = 0; if (retval) retval = udhcp_str2nip(val, buffer + 4); break; case_OPTION_STRING: case OPTION_STRING: case OPTION_STRING_HOST: #if ENABLE_FEATURE_UDHCP_RFC3397 case OPTION_DNS_STRING: #endif length = strnlen(val, 254); if (length > 0) { opt = val; retval = 1; } break; // case OPTION_BOOLEAN: { // static const char no_yes[] ALIGN1 = "no\0yes\0"; // buffer[0] = retval = index_in_strings(no_yes, val); // retval++; /* 0 - bad; 1: "no" 2: "yes" */ // break; // } case OPTION_U8: buffer[0] = bb_strtou32(val, NULL, 0); retval = (errno == 0); break; /* htonX are macros in older libc's, using temp var * in code below for safety */ /* TODO: use bb_strtoX? */ case OPTION_U16: { uint32_t tmp = bb_strtou32(val, NULL, 0); *result_u16 = htons(tmp); retval = (errno == 0 /*&& tmp < 0x10000*/); break; } // case OPTION_S16: { // long tmp = bb_strtoi32(val, NULL, 0); // *result_u16 = htons(tmp); // retval = (errno == 0); // break; // } case OPTION_U32: { uint32_t tmp = bb_strtou32(val, NULL, 0); *result_u32 = htonl(tmp); retval = (errno == 0); break; } case OPTION_S32: { int32_t tmp = bb_strtoi32(val, NULL, 0); *result_u32 = htonl(tmp); retval = (errno == 0); break; } case OPTION_STATIC_ROUTES: { /* Input: "a.b.c.d/m" */ /* Output: mask(1 byte),pfx(0-4 bytes),gw(4 bytes) */ unsigned mask; char *slash = strchr(val, '/'); if (slash) { *slash = '\0'; retval = udhcp_str2nip(val, buffer + 1); buffer[0] = mask = bb_strtou(slash + 1, NULL, 10); val = strtok(NULL, ", \t/-"); if (!val || mask > 32 || errno) retval = 0; if (retval) { length = ((mask + 7) >> 3) + 5; retval = udhcp_str2nip(val, buffer + (length - 4)); } } break; } case OPTION_BIN: /* Raw (numeric) option code. Is it a string? */ if (val[0] == '"' || val[0] == '\'') { char delim = val[0]; char *end = last_char_is(val + 1, delim); if (end) { *end = '\0'; val++; userdef_optflag.flags = OPTION_STRING; goto case_OPTION_STRING; } } /* No: hex-str option, handled in attach_option() */ opt = val; retval = 1; break; default: break; } if (retval) attach_option(opt_list, optflag, opt, length); } while (retval && (optflag->flags & OPTION_LIST)); return retval; } /* note: ip is a pointer to an IPv6 in network order, possibly misaliged */ int FAST_FUNC sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) { char hexstrbuf[16 * 2]; bin2hex(hexstrbuf, (void*)ip, 16); return sprintf(dest, /* "%s" */ "%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s", /* pre, */ hexstrbuf + 0 * 4, hexstrbuf + 1 * 4, hexstrbuf + 2 * 4, hexstrbuf + 3 * 4, hexstrbuf + 4 * 4, hexstrbuf + 5 * 4, hexstrbuf + 6 * 4, hexstrbuf + 7 * 4 ); }