| /* vi: set sw=4 ts=4: */ |
| /* |
| * udhcp client |
| * Russ Dill <Russ.Dill@asu.edu> July 2001 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| //applet:IF_UDHCPC(APPLET(udhcpc, BB_DIR_SBIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_UDHCPC) += common.o packet.o signalpipe.o socket.o |
| //kbuild:lib-$(CONFIG_UDHCPC) += dhcpc.o |
| //kbuild:lib-$(CONFIG_FEATURE_UDHCPC_ARPING) += arpping.o |
| //kbuild:lib-$(CONFIG_FEATURE_UDHCP_RFC3397) += domain_codec.o |
| |
| #include <syslog.h> |
| /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */ |
| #define WANT_PIDFILE 1 |
| #include "common.h" |
| #include "dhcpd.h" |
| #include "dhcpc.h" |
| |
| #include <netinet/if_ether.h> |
| #include <linux/filter.h> |
| #include <linux/if_packet.h> |
| |
| #ifndef PACKET_AUXDATA |
| # define PACKET_AUXDATA 8 |
| struct tpacket_auxdata { |
| uint32_t tp_status; |
| uint32_t tp_len; |
| uint32_t tp_snaplen; |
| uint16_t tp_mac; |
| uint16_t tp_net; |
| uint16_t tp_vlan_tci; |
| uint16_t tp_padding; |
| }; |
| #endif |
| |
| |
| /* "struct client_config_t client_config" is in bb_common_bufsiz1 */ |
| |
| |
| #if ENABLE_LONG_OPTS |
| static const char udhcpc_longopts[] ALIGN1 = |
| "clientid-none\0" No_argument "C" |
| "vendorclass\0" Required_argument "V" |
| "hostname\0" Required_argument "H" |
| "fqdn\0" Required_argument "F" |
| "interface\0" Required_argument "i" |
| "now\0" No_argument "n" |
| "pidfile\0" Required_argument "p" |
| "quit\0" No_argument "q" |
| "release\0" No_argument "R" |
| "request\0" Required_argument "r" |
| "script\0" Required_argument "s" |
| "timeout\0" Required_argument "T" |
| "retries\0" Required_argument "t" |
| "tryagain\0" Required_argument "A" |
| "syslog\0" No_argument "S" |
| "request-option\0" Required_argument "O" |
| "no-default-options\0" No_argument "o" |
| "foreground\0" No_argument "f" |
| USE_FOR_MMU( |
| "background\0" No_argument "b" |
| ) |
| "broadcast\0" No_argument "B" |
| IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a") |
| IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P") |
| ; |
| #endif |
| /* Must match getopt32 option string order */ |
| enum { |
| OPT_C = 1 << 0, |
| OPT_V = 1 << 1, |
| OPT_H = 1 << 2, |
| OPT_h = 1 << 3, |
| OPT_F = 1 << 4, |
| OPT_i = 1 << 5, |
| OPT_n = 1 << 6, |
| OPT_p = 1 << 7, |
| OPT_q = 1 << 8, |
| OPT_R = 1 << 9, |
| OPT_r = 1 << 10, |
| OPT_s = 1 << 11, |
| OPT_T = 1 << 12, |
| OPT_t = 1 << 13, |
| OPT_S = 1 << 14, |
| OPT_A = 1 << 15, |
| OPT_O = 1 << 16, |
| OPT_o = 1 << 17, |
| OPT_x = 1 << 18, |
| OPT_f = 1 << 19, |
| OPT_B = 1 << 20, |
| /* The rest has variable bit positions, need to be clever */ |
| OPTBIT_B = 20, |
| USE_FOR_MMU( OPTBIT_b,) |
| IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,) |
| IF_FEATURE_UDHCP_PORT( OPTBIT_P,) |
| USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,) |
| IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,) |
| IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,) |
| }; |
| |
| |
| /*** Script execution code ***/ |
| |
| /* get a rough idea of how long an option will be (rounding up...) */ |
| static const uint8_t len_of_option_as_string[] ALIGN1 = { |
| [OPTION_IP ] = sizeof("255.255.255.255 "), |
| [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2, |
| [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "), |
| [OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "), |
| [OPTION_STRING ] = 1, |
| [OPTION_STRING_HOST ] = 1, |
| #if ENABLE_FEATURE_UDHCP_RFC3397 |
| [OPTION_DNS_STRING ] = 1, /* unused */ |
| /* Hmmm, this severely overestimates size if SIP_SERVERS option |
| * is in domain name form: N-byte option in binary form |
| * mallocs ~16*N bytes. But it is freed almost at once. |
| */ |
| [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "), |
| #endif |
| // [OPTION_BOOLEAN ] = sizeof("yes "), |
| [OPTION_U8 ] = sizeof("255 "), |
| [OPTION_U16 ] = sizeof("65535 "), |
| // [OPTION_S16 ] = sizeof("-32768 "), |
| [OPTION_U32 ] = sizeof("4294967295 "), |
| [OPTION_S32 ] = sizeof("-2147483684 "), |
| }; |
| |
| /* note: ip is a pointer to an IP in network order, possibly misaliged */ |
| static int sprint_nip(char *dest, const char *pre, const uint8_t *ip) |
| { |
| return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]); |
| } |
| |
| /* really simple implementation, just count the bits */ |
| static int mton(uint32_t mask) |
| { |
| int i = 0; |
| mask = ntohl(mask); /* 111110000-like bit pattern */ |
| while (mask) { |
| i++; |
| mask <<= 1; |
| } |
| return i; |
| } |
| |
| #if ENABLE_FEATURE_UDHCPC_SANITIZEOPT |
| /* Check if a given label represents a valid DNS label |
| * Return pointer to the first character after the label upon success, |
| * NULL otherwise. |
| * See RFC1035, 2.3.1 |
| */ |
| /* We don't need to be particularly anal. For example, allowing _, hyphen |
| * at the end, or leading and trailing dots would be ok, since it |
| * can't be used for attacks. (Leading hyphen can be, if someone uses |
| * cmd "$hostname" |
| * in the script: then hostname may be treated as an option) |
| */ |
| static const char *valid_domain_label(const char *label) |
| { |
| unsigned char ch; |
| unsigned pos = 0; |
| |
| for (;;) { |
| ch = *label; |
| if ((ch|0x20) < 'a' || (ch|0x20) > 'z') { |
| if (ch < '0' || ch > '9') { |
| if (ch == '\0' || ch == '.') |
| return label; |
| /* DNS allows only '-', but we are more permissive */ |
| if (ch != '-' && ch != '_') |
| return NULL; |
| } |
| } |
| label++; |
| pos++; |
| //Do we want this? |
| //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */ |
| // return NULL; |
| } |
| } |
| |
| /* Check if a given name represents a valid DNS name */ |
| /* See RFC1035, 2.3.1 */ |
| static int good_hostname(const char *name) |
| { |
| //const char *start = name; |
| |
| for (;;) { |
| name = valid_domain_label(name); |
| if (!name) |
| return 0; |
| if (!name[0]) |
| return 1; |
| //Do we want this? |
| //return ((name - start) < 1025); /* NS_MAXDNAME */ |
| name++; |
| if (*name == '\0') |
| return 1; // We allow trailing dot too |
| } |
| } |
| #else |
| # define good_hostname(name) 1 |
| #endif |
| |
| /* Create "opt_name=opt_value" string */ |
| static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name) |
| { |
| unsigned upper_length; |
| int len, type, optlen; |
| char *dest, *ret; |
| |
| /* option points to OPT_DATA, need to go back to get OPT_LEN */ |
| len = option[-OPT_DATA + OPT_LEN]; |
| |
| type = optflag->flags & OPTION_TYPE_MASK; |
| optlen = dhcp_option_lengths[type]; |
| upper_length = len_of_option_as_string[type] |
| * ((unsigned)(len + optlen) / (unsigned)optlen); |
| |
| dest = ret = xmalloc(upper_length + strlen(opt_name) + 2); |
| dest += sprintf(ret, "%s=", opt_name); |
| |
| while (len >= optlen) { |
| switch (type) { |
| case OPTION_IP: |
| case OPTION_IP_PAIR: |
| dest += sprint_nip(dest, "", option); |
| if (type == OPTION_IP) |
| break; |
| dest += sprint_nip(dest, "/", option + 4); |
| break; |
| // case OPTION_BOOLEAN: |
| // dest += sprintf(dest, *option ? "yes" : "no"); |
| // break; |
| case OPTION_U8: |
| dest += sprintf(dest, "%u", *option); |
| break; |
| // case OPTION_S16: |
| case OPTION_U16: { |
| uint16_t val_u16; |
| move_from_unaligned16(val_u16, option); |
| dest += sprintf(dest, "%u", ntohs(val_u16)); |
| break; |
| } |
| case OPTION_S32: |
| case OPTION_U32: { |
| uint32_t val_u32; |
| move_from_unaligned32(val_u32, option); |
| dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32)); |
| break; |
| } |
| /* Note: options which use 'return' instead of 'break' |
| * (for example, OPTION_STRING) skip the code which handles |
| * the case of list of options. |
| */ |
| case OPTION_STRING: |
| case OPTION_STRING_HOST: |
| memcpy(dest, option, len); |
| dest[len] = '\0'; |
| if (type == OPTION_STRING_HOST && !good_hostname(dest)) |
| safe_strncpy(dest, "bad", len); |
| return ret; |
| case OPTION_STATIC_ROUTES: { |
| /* Option binary format: |
| * mask [one byte, 0..32] |
| * ip [big endian, 0..4 bytes depending on mask] |
| * router [big endian, 4 bytes] |
| * may be repeated |
| * |
| * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2" |
| */ |
| const char *pfx = ""; |
| |
| while (len >= 1 + 4) { /* mask + 0-byte ip + router */ |
| uint32_t nip; |
| uint8_t *p; |
| unsigned mask; |
| int bytes; |
| |
| mask = *option++; |
| if (mask > 32) |
| break; |
| len--; |
| |
| nip = 0; |
| p = (void*) &nip; |
| bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */ |
| while (--bytes >= 0) { |
| *p++ = *option++; |
| len--; |
| } |
| if (len < 4) |
| break; |
| |
| /* print ip/mask */ |
| dest += sprint_nip(dest, pfx, (void*) &nip); |
| pfx = " "; |
| dest += sprintf(dest, "/%u ", mask); |
| /* print router */ |
| dest += sprint_nip(dest, "", option); |
| option += 4; |
| len -= 4; |
| } |
| |
| return ret; |
| } |
| case OPTION_6RD: |
| /* Option binary format (see RFC 5969): |
| * 0 1 2 3 |
| * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | 6rdPrefix | |
| * ... (16 octets) ... |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * ... 6rdBRIPv4Address(es) ... |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * We convert it to a string |
| * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..." |
| * |
| * Sanity check: ensure that our length is at least 22 bytes, that |
| * IPv4MaskLen <= 32, |
| * 6rdPrefixLen <= 128, |
| * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128 |
| * (2nd condition need no check - it follows from 1st and 3rd). |
| * Else, return envvar with empty value ("optname=") |
| */ |
| if (len >= (1 + 1 + 16 + 4) |
| && option[0] <= 32 |
| && (option[1] + 32 - option[0]) <= 128 |
| ) { |
| /* IPv4MaskLen */ |
| dest += sprintf(dest, "%u ", *option++); |
| /* 6rdPrefixLen */ |
| dest += sprintf(dest, "%u ", *option++); |
| /* 6rdPrefix */ |
| dest += sprint_nip6(dest, /* "", */ option); |
| option += 16; |
| len -= 1 + 1 + 16 + 4; |
| /* "+ 4" above corresponds to the length of IPv4 addr |
| * we consume in the loop below */ |
| while (1) { |
| /* 6rdBRIPv4Address(es) */ |
| dest += sprint_nip(dest, " ", option); |
| option += 4; |
| len -= 4; /* do we have yet another 4+ bytes? */ |
| if (len < 0) |
| break; /* no */ |
| } |
| } |
| |
| return ret; |
| #if ENABLE_FEATURE_UDHCP_RFC3397 |
| case OPTION_DNS_STRING: |
| /* unpack option into dest; use ret for prefix (i.e., "optname=") */ |
| dest = dname_dec(option, len, ret); |
| if (dest) { |
| free(ret); |
| return dest; |
| } |
| /* error. return "optname=" string */ |
| return ret; |
| case OPTION_SIP_SERVERS: |
| /* Option binary format: |
| * type: byte |
| * type=0: domain names, dns-compressed |
| * type=1: IP addrs |
| */ |
| option++; |
| len--; |
| if (option[-1] == 0) { |
| dest = dname_dec(option, len, ret); |
| if (dest) { |
| free(ret); |
| return dest; |
| } |
| } else |
| if (option[-1] == 1) { |
| const char *pfx = ""; |
| while (1) { |
| len -= 4; |
| if (len < 0) |
| break; |
| dest += sprint_nip(dest, pfx, option); |
| pfx = " "; |
| option += 4; |
| } |
| } |
| return ret; |
| #endif |
| } /* switch */ |
| |
| /* If we are here, try to format any remaining data |
| * in the option as another, similarly-formatted option |
| */ |
| option += optlen; |
| len -= optlen; |
| // TODO: it can be a list only if (optflag->flags & OPTION_LIST). |
| // Should we bail out/warn if we see multi-ip option which is |
| // not allowed to be such (for example, DHCP_BROADCAST)? - |
| if (len < optlen /* || !(optflag->flags & OPTION_LIST) */) |
| break; |
| *dest++ = ' '; |
| *dest = '\0'; |
| } /* while */ |
| |
| return ret; |
| } |
| |
| /* put all the parameters into the environment */ |
| static char **fill_envp(struct dhcp_packet *packet) |
| { |
| int envc; |
| int i; |
| char **envp, **curr; |
| const char *opt_name; |
| uint8_t *temp; |
| uint8_t overload = 0; |
| |
| #define BITMAP unsigned |
| #define BBITS (sizeof(BITMAP) * 8) |
| #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1))) |
| #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS]) |
| BITMAP found_opts[256 / BBITS]; |
| |
| memset(found_opts, 0, sizeof(found_opts)); |
| |
| /* We need 6 elements for: |
| * "interface=IFACE" |
| * "ip=N.N.N.N" from packet->yiaddr |
| * "siaddr=IP" from packet->siaddr_nip (unless 0) |
| * "boot_file=FILE" from packet->file (unless overloaded) |
| * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded) |
| * terminating NULL |
| */ |
| envc = 6; |
| /* +1 element for each option, +2 for subnet option: */ |
| if (packet) { |
| /* note: do not search for "pad" (0) and "end" (255) options */ |
| //TODO: change logic to scan packet _once_ |
| for (i = 1; i < 255; i++) { |
| temp = udhcp_get_option(packet, i); |
| if (temp) { |
| if (i == DHCP_OPTION_OVERLOAD) |
| overload |= *temp; |
| else if (i == DHCP_SUBNET) |
| envc++; /* for $mask */ |
| envc++; |
| /*if (i != DHCP_MESSAGE_TYPE)*/ |
| FOUND_OPTS(i) |= BMASK(i); |
| } |
| } |
| } |
| curr = envp = xzalloc(sizeof(envp[0]) * envc); |
| |
| *curr = xasprintf("interface=%s", client_config.interface); |
| putenv(*curr++); |
| |
| if (!packet) |
| return envp; |
| |
| /* Export BOOTP fields. Fields we don't (yet?) export: |
| * uint8_t op; // always BOOTREPLY |
| * uint8_t htype; // hardware address type. 1 = 10mb ethernet |
| * uint8_t hlen; // hardware address length |
| * uint8_t hops; // used by relay agents only |
| * uint32_t xid; |
| * uint16_t secs; // elapsed since client began acquisition/renewal |
| * uint16_t flags; // only one flag so far: bcast. Never set by server |
| * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different |
| * // if during renew server wants to give us different IP?) |
| * uint32_t gateway_nip; // relay agent IP address |
| * uint8_t chaddr[16]; // link-layer client hardware address (MAC) |
| * TODO: export gateway_nip as $giaddr? |
| */ |
| /* Most important one: yiaddr as $ip */ |
| *curr = xmalloc(sizeof("ip=255.255.255.255")); |
| sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr); |
| putenv(*curr++); |
| if (packet->siaddr_nip) { |
| /* IP address of next server to use in bootstrap */ |
| *curr = xmalloc(sizeof("siaddr=255.255.255.255")); |
| sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip); |
| putenv(*curr++); |
| } |
| if (!(overload & FILE_FIELD) && packet->file[0]) { |
| /* watch out for invalid packets */ |
| *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); |
| putenv(*curr++); |
| } |
| if (!(overload & SNAME_FIELD) && packet->sname[0]) { |
| /* watch out for invalid packets */ |
| *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); |
| putenv(*curr++); |
| } |
| |
| /* Export known DHCP options */ |
| opt_name = dhcp_option_strings; |
| i = 0; |
| while (*opt_name) { |
| uint8_t code = dhcp_optflags[i].code; |
| BITMAP *found_ptr = &FOUND_OPTS(code); |
| BITMAP found_mask = BMASK(code); |
| if (!(*found_ptr & found_mask)) |
| goto next; |
| *found_ptr &= ~found_mask; /* leave only unknown options */ |
| temp = udhcp_get_option(packet, code); |
| *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name); |
| putenv(*curr++); |
| if (code == DHCP_SUBNET) { |
| /* Subnet option: make things like "$ip/$mask" possible */ |
| uint32_t subnet; |
| move_from_unaligned32(subnet, temp); |
| *curr = xasprintf("mask=%u", mton(subnet)); |
| putenv(*curr++); |
| } |
| next: |
| opt_name += strlen(opt_name) + 1; |
| i++; |
| } |
| /* Export unknown options */ |
| for (i = 0; i < 256;) { |
| BITMAP bitmap = FOUND_OPTS(i); |
| if (!bitmap) { |
| i += BBITS; |
| continue; |
| } |
| if (bitmap & BMASK(i)) { |
| unsigned len, ofs; |
| |
| temp = udhcp_get_option(packet, i); |
| /* udhcp_get_option returns ptr to data portion, |
| * need to go back to get len |
| */ |
| len = temp[-OPT_DATA + OPT_LEN]; |
| *curr = xmalloc(sizeof("optNNN=") + 1 + len*2); |
| ofs = sprintf(*curr, "opt%u=", i); |
| *bin2hex(*curr + ofs, (void*) temp, len) = '\0'; |
| putenv(*curr++); |
| } |
| i++; |
| } |
| |
| return envp; |
| } |
| |
| /* Call a script with a par file and env vars */ |
| static void udhcp_run_script(struct dhcp_packet *packet, const char *name) |
| { |
| char **envp, **curr; |
| char *argv[3]; |
| |
| envp = fill_envp(packet); |
| |
| /* call script */ |
| log1("executing %s %s", client_config.script, name); |
| argv[0] = (char*) client_config.script; |
| argv[1] = (char*) name; |
| argv[2] = NULL; |
| spawn_and_wait(argv); |
| |
| for (curr = envp; *curr; curr++) { |
| log2(" %s", *curr); |
| bb_unsetenv_and_free(*curr); |
| } |
| free(envp); |
| } |
| |
| |
| /*** Sending/receiving packets ***/ |
| |
| static ALWAYS_INLINE uint32_t random_xid(void) |
| { |
| return rand(); |
| } |
| |
| /* Initialize the packet with the proper defaults */ |
| static void init_packet(struct dhcp_packet *packet, char type) |
| { |
| uint16_t secs; |
| |
| /* Fill in: op, htype, hlen, cookie fields; message type option: */ |
| udhcp_init_header(packet, type); |
| |
| packet->xid = random_xid(); |
| |
| client_config.last_secs = monotonic_sec(); |
| if (client_config.first_secs == 0) |
| client_config.first_secs = client_config.last_secs; |
| secs = client_config.last_secs - client_config.first_secs; |
| packet->secs = htons(secs); |
| |
| memcpy(packet->chaddr, client_config.client_mac, 6); |
| if (client_config.clientid) |
| udhcp_add_binary_option(packet, client_config.clientid); |
| } |
| |
| static void add_client_options(struct dhcp_packet *packet) |
| { |
| int i, end, len; |
| |
| udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE)); |
| |
| /* Add a "param req" option with the list of options we'd like to have |
| * from stubborn DHCP servers. Pull the data from the struct in common.c. |
| * No bounds checking because it goes towards the head of the packet. */ |
| end = udhcp_end_option(packet->options); |
| len = 0; |
| for (i = 1; i < DHCP_END; i++) { |
| if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) { |
| packet->options[end + OPT_DATA + len] = i; |
| len++; |
| } |
| } |
| if (len) { |
| packet->options[end + OPT_CODE] = DHCP_PARAM_REQ; |
| packet->options[end + OPT_LEN] = len; |
| packet->options[end + OPT_DATA + len] = DHCP_END; |
| } |
| |
| if (client_config.vendorclass) |
| udhcp_add_binary_option(packet, client_config.vendorclass); |
| if (client_config.hostname) |
| udhcp_add_binary_option(packet, client_config.hostname); |
| if (client_config.fqdn) |
| udhcp_add_binary_option(packet, client_config.fqdn); |
| |
| /* Request broadcast replies if we have no IP addr */ |
| if ((option_mask32 & OPT_B) && packet->ciaddr == 0) |
| packet->flags |= htons(BROADCAST_FLAG); |
| |
| /* Add -x options if any */ |
| { |
| struct option_set *curr = client_config.options; |
| while (curr) { |
| udhcp_add_binary_option(packet, curr->data); |
| curr = curr->next; |
| } |
| // if (client_config.sname) |
| // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1); |
| // if (client_config.boot_file) |
| // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1); |
| } |
| |
| // This will be needed if we remove -V VENDOR_STR in favor of |
| // -x vendor:VENDOR_STR |
| //if (!udhcp_find_option(packet.options, DHCP_VENDOR)) |
| // /* not set, set the default vendor ID */ |
| // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt... |
| } |
| |
| /* RFC 2131 |
| * 4.4.4 Use of broadcast and unicast |
| * |
| * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM |
| * messages, unless the client knows the address of a DHCP server. |
| * The client unicasts DHCPRELEASE messages to the server. Because |
| * the client is declining the use of the IP address supplied by the server, |
| * the client broadcasts DHCPDECLINE messages. |
| * |
| * When the DHCP client knows the address of a DHCP server, in either |
| * INIT or REBOOTING state, the client may use that address |
| * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address. |
| * The client may also use unicast to send DHCPINFORM messages |
| * to a known DHCP server. If the client receives no response to DHCP |
| * messages sent to the IP address of a known DHCP server, the DHCP |
| * client reverts to using the IP broadcast address. |
| */ |
| |
| static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip) |
| { |
| return udhcp_send_raw_packet(packet, |
| /*src*/ src_nip, CLIENT_PORT, |
| /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR, |
| client_config.ifindex); |
| } |
| |
| static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server) |
| { |
| if (server) { |
| /* Without MSG_DONTROUTE, the packet was seen routed over |
| * _other interface_ if server ID is bogus (example: 1.1.1.1). |
| */ |
| return udhcp_send_kernel_packet(packet, |
| ciaddr, CLIENT_PORT, |
| server, SERVER_PORT, |
| /*send_flags: "to hosts only on directly connected networks" */ MSG_DONTROUTE |
| ); |
| } |
| return raw_bcast_from_client_config_ifindex(packet, ciaddr); |
| } |
| |
| /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ |
| /* NOINLINE: limit stack usage in caller */ |
| static NOINLINE int send_discover(uint32_t xid, uint32_t requested) |
| { |
| struct dhcp_packet packet; |
| |
| /* Fill in: op, htype, hlen, cookie, chaddr fields, |
| * random xid field (we override it below), |
| * client-id option (unless -C), message type option: |
| */ |
| init_packet(&packet, DHCPDISCOVER); |
| |
| packet.xid = xid; |
| if (requested) |
| udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested); |
| |
| /* Add options: maxsize, |
| * optionally: hostname, fqdn, vendorclass, |
| * "param req" option according to -O, options specified with -x |
| */ |
| add_client_options(&packet); |
| |
| bb_error_msg("sending %s", "discover"); |
| return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY); |
| } |
| |
| /* Broadcast a DHCP request message */ |
| /* RFC 2131 3.1 paragraph 3: |
| * "The client _broadcasts_ a DHCPREQUEST message..." |
| */ |
| /* NOINLINE: limit stack usage in caller */ |
| static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested) |
| { |
| struct dhcp_packet packet; |
| struct in_addr temp_addr; |
| |
| /* |
| * RFC 2131 4.3.2 DHCPREQUEST message |
| * ... |
| * If the DHCPREQUEST message contains a 'server identifier' |
| * option, the message is in response to a DHCPOFFER message. |
| * Otherwise, the message is a request to verify or extend an |
| * existing lease. If the client uses a 'client identifier' |
| * in a DHCPREQUEST message, it MUST use that same 'client identifier' |
| * in all subsequent messages. If the client included a list |
| * of requested parameters in a DHCPDISCOVER message, it MUST |
| * include that list in all subsequent messages. |
| */ |
| /* Fill in: op, htype, hlen, cookie, chaddr fields, |
| * random xid field (we override it below), |
| * client-id option (unless -C), message type option: |
| */ |
| init_packet(&packet, DHCPREQUEST); |
| |
| packet.xid = xid; |
| udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested); |
| |
| udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server); |
| |
| /* Add options: maxsize, |
| * optionally: hostname, fqdn, vendorclass, |
| * "param req" option according to -O, and options specified with -x |
| */ |
| add_client_options(&packet); |
| |
| temp_addr.s_addr = requested; |
| bb_error_msg("sending select for %s", inet_ntoa(temp_addr)); |
| return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY); |
| } |
| |
| /* Unicast or broadcast a DHCP renew message */ |
| /* NOINLINE: limit stack usage in caller */ |
| static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) |
| { |
| struct dhcp_packet packet; |
| struct in_addr temp_addr; |
| |
| /* |
| * RFC 2131 4.3.2 DHCPREQUEST message |
| * ... |
| * DHCPREQUEST generated during RENEWING state: |
| * |
| * 'server identifier' MUST NOT be filled in, 'requested IP address' |
| * option MUST NOT be filled in, 'ciaddr' MUST be filled in with |
| * client's IP address. In this situation, the client is completely |
| * configured, and is trying to extend its lease. This message will |
| * be unicast, so no relay agents will be involved in its |
| * transmission. Because 'giaddr' is therefore not filled in, the |
| * DHCP server will trust the value in 'ciaddr', and use it when |
| * replying to the client. |
| */ |
| /* Fill in: op, htype, hlen, cookie, chaddr fields, |
| * random xid field (we override it below), |
| * client-id option (unless -C), message type option: |
| */ |
| init_packet(&packet, DHCPREQUEST); |
| |
| packet.xid = xid; |
| packet.ciaddr = ciaddr; |
| |
| /* Add options: maxsize, |
| * optionally: hostname, fqdn, vendorclass, |
| * "param req" option according to -O, and options specified with -x |
| */ |
| add_client_options(&packet); |
| |
| temp_addr.s_addr = server; |
| bb_error_msg("sending renew to %s", inet_ntoa(temp_addr)); |
| return bcast_or_ucast(&packet, ciaddr, server); |
| } |
| |
| #if ENABLE_FEATURE_UDHCPC_ARPING |
| /* Broadcast a DHCP decline message */ |
| /* NOINLINE: limit stack usage in caller */ |
| static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested) |
| { |
| struct dhcp_packet packet; |
| |
| /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields, |
| * client-id option (unless -C), message type option: |
| */ |
| init_packet(&packet, DHCPDECLINE); |
| |
| #if 0 |
| /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client, |
| * but in case the server is buggy and wants DHCPDECLINE's xid |
| * to match the xid which started entire handshake, |
| * we use the same xid we used in initial DHCPDISCOVER: |
| */ |
| packet.xid = xid; |
| #endif |
| /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */ |
| udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested); |
| |
| udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server); |
| |
| bb_error_msg("sending %s", "decline"); |
| return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY); |
| } |
| #endif |
| |
| /* Unicast a DHCP release message */ |
| static int send_release(uint32_t server, uint32_t ciaddr) |
| { |
| struct dhcp_packet packet; |
| |
| /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields, |
| * client-id option (unless -C), message type option: |
| */ |
| init_packet(&packet, DHCPRELEASE); |
| |
| /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */ |
| packet.ciaddr = ciaddr; |
| |
| udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server); |
| |
| bb_error_msg("sending %s", "release"); |
| /* Note: normally we unicast here since "server" is not zero. |
| * However, there _are_ people who run "address-less" DHCP servers, |
| * and reportedly ISC dhcp client and Windows allow that. |
| */ |
| return bcast_or_ucast(&packet, ciaddr, server); |
| } |
| |
| /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */ |
| /* NOINLINE: limit stack usage in caller */ |
| static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) |
| { |
| int bytes; |
| struct ip_udp_dhcp_packet packet; |
| uint16_t check; |
| unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))]; |
| struct iovec iov; |
| struct msghdr msg; |
| struct cmsghdr *cmsg; |
| |
| /* used to use just safe_read(fd, &packet, sizeof(packet)) |
| * but we need to check for TP_STATUS_CSUMNOTREADY :( |
| */ |
| iov.iov_base = &packet; |
| iov.iov_len = sizeof(packet); |
| memset(&msg, 0, sizeof(msg)); |
| msg.msg_iov = &iov; |
| msg.msg_iovlen = 1; |
| msg.msg_control = cmsgbuf; |
| msg.msg_controllen = sizeof(cmsgbuf); |
| for (;;) { |
| bytes = recvmsg(fd, &msg, 0); |
| if (bytes < 0) { |
| if (errno == EINTR) |
| continue; |
| log1("packet read error, ignoring"); |
| /* NB: possible down interface, etc. Caller should pause. */ |
| return bytes; /* returns -1 */ |
| } |
| break; |
| } |
| |
| if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) { |
| log1("packet is too short, ignoring"); |
| return -2; |
| } |
| |
| if (bytes < ntohs(packet.ip.tot_len)) { |
| /* packet is bigger than sizeof(packet), we did partial read */ |
| log1("oversized packet, ignoring"); |
| return -2; |
| } |
| |
| /* ignore any extra garbage bytes */ |
| bytes = ntohs(packet.ip.tot_len); |
| |
| /* make sure its the right packet for us, and that it passes sanity checks */ |
| if (packet.ip.protocol != IPPROTO_UDP |
| || packet.ip.version != IPVERSION |
| || packet.ip.ihl != (sizeof(packet.ip) >> 2) |
| || packet.udp.dest != htons(CLIENT_PORT) |
| /* || bytes > (int) sizeof(packet) - can't happen */ |
| || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip)) |
| ) { |
| log1("unrelated/bogus packet, ignoring"); |
| return -2; |
| } |
| |
| /* verify IP checksum */ |
| check = packet.ip.check; |
| packet.ip.check = 0; |
| if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) { |
| log1("bad IP header checksum, ignoring"); |
| return -2; |
| } |
| |
| for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| if (cmsg->cmsg_level == SOL_PACKET |
| && cmsg->cmsg_type == PACKET_AUXDATA |
| ) { |
| /* some VMs don't checksum UDP and TCP data |
| * they send to the same physical machine, |
| * here we detect this case: |
| */ |
| struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg); |
| if (aux->tp_status & TP_STATUS_CSUMNOTREADY) |
| goto skip_udp_sum_check; |
| } |
| } |
| |
| /* verify UDP checksum. IP header has to be modified for this */ |
| memset(&packet.ip, 0, offsetof(struct iphdr, protocol)); |
| /* ip.xx fields which are not memset: protocol, check, saddr, daddr */ |
| packet.ip.tot_len = packet.udp.len; /* yes, this is needed */ |
| check = packet.udp.check; |
| packet.udp.check = 0; |
| if (check && check != inet_cksum((uint16_t *)&packet, bytes)) { |
| log1("packet with bad UDP checksum received, ignoring"); |
| return -2; |
| } |
| skip_udp_sum_check: |
| |
| if (packet.data.cookie != htonl(DHCP_MAGIC)) { |
| bb_error_msg("packet with bad magic, ignoring"); |
| return -2; |
| } |
| |
| log1("received %s", "a packet"); |
| udhcp_dump_packet(&packet.data); |
| |
| bytes -= sizeof(packet.ip) + sizeof(packet.udp); |
| memcpy(dhcp_pkt, &packet.data, bytes); |
| return bytes; |
| } |
| |
| |
| /*** Main ***/ |
| |
| static int sockfd = -1; |
| |
| #define LISTEN_NONE 0 |
| #define LISTEN_KERNEL 1 |
| #define LISTEN_RAW 2 |
| static smallint listen_mode; |
| |
| /* initial state: (re)start DHCP negotiation */ |
| #define INIT_SELECTING 0 |
| /* discover was sent, DHCPOFFER reply received */ |
| #define REQUESTING 1 |
| /* select/renew was sent, DHCPACK reply received */ |
| #define BOUND 2 |
| /* half of lease passed, want to renew it by sending unicast renew requests */ |
| #define RENEWING 3 |
| /* renew requests were not answered, lease is almost over, send broadcast renew */ |
| #define REBINDING 4 |
| /* manually requested renew (SIGUSR1) */ |
| #define RENEW_REQUESTED 5 |
| /* release, possibly manually requested (SIGUSR2) */ |
| #define RELEASED 6 |
| static smallint state; |
| |
| static int udhcp_raw_socket(int ifindex) |
| { |
| int fd; |
| struct sockaddr_ll sock; |
| |
| log2("opening raw socket on ifindex %d", ifindex); |
| |
| fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP)); |
| /* ^^^^^ |
| * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them) |
| * ETH_P_IP: want to receive only packets with IPv4 eth type |
| */ |
| log2("got raw socket fd"); |
| |
| memset(&sock, 0, sizeof(sock)); /* let's be deterministic */ |
| sock.sll_family = AF_PACKET; |
| sock.sll_protocol = htons(ETH_P_IP); |
| sock.sll_ifindex = ifindex; |
| /*sock.sll_hatype = ARPHRD_???;*/ |
| /*sock.sll_pkttype = PACKET_???;*/ |
| /*sock.sll_halen = ???;*/ |
| /*sock.sll_addr[8] = ???;*/ |
| xbind(fd, (struct sockaddr *) &sock, sizeof(sock)); |
| |
| #if 0 /* Several users reported breakage when BPF filter is used */ |
| if (CLIENT_PORT == 68) { |
| /* Use only if standard port is in use */ |
| /* |
| * I've selected not to see LL header, so BPF doesn't see it, too. |
| * The filter may also pass non-IP and non-ARP packets, but we do |
| * a more complete check when receiving the message in userspace. |
| * |
| * and filter shamelessly stolen from: |
| * |
| * http://www.flamewarmaster.de/software/dhcpclient/ |
| * |
| * There are a few other interesting ideas on that page (look under |
| * "Motivation"). Use of netlink events is most interesting. Think |
| * of various network servers listening for events and reconfiguring. |
| * That would obsolete sending HUP signals and/or make use of restarts. |
| * |
| * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>. |
| * License: GPL v2. |
| */ |
| static const struct sock_filter filter_instr[] = { |
| /* load 9th byte (protocol) */ |
| BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9), |
| /* jump to L1 if it is IPPROTO_UDP, else to L4 */ |
| BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6), |
| /* L1: load halfword from offset 6 (flags and frag offset) */ |
| BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6), |
| /* jump to L4 if any bits in frag offset field are set, else to L2 */ |
| BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0), |
| /* L2: skip IP header (load index reg with header len) */ |
| BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), |
| /* load udp destination port from halfword[header_len + 2] */ |
| BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2), |
| /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */ |
| BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1), |
| /* L3: accept packet ("accept 0x7fffffff bytes") */ |
| /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */ |
| BPF_STMT(BPF_RET|BPF_K, 0x7fffffff), |
| /* L4: discard packet ("accept zero bytes") */ |
| BPF_STMT(BPF_RET|BPF_K, 0), |
| }; |
| static const struct sock_fprog filter_prog = { |
| .len = sizeof(filter_instr) / sizeof(filter_instr[0]), |
| /* casting const away: */ |
| .filter = (struct sock_filter *) filter_instr, |
| }; |
| /* Ignoring error (kernel may lack support for this) */ |
| if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog, |
| sizeof(filter_prog)) >= 0) |
| log1("attached filter to raw socket fd"); // log? |
| } |
| #endif |
| |
| if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) { |
| if (errno != ENOPROTOOPT) |
| log1("can't set PACKET_AUXDATA on raw socket"); |
| } |
| |
| log1("created raw socket"); |
| |
| return fd; |
| } |
| |
| static void change_listen_mode(int new_mode) |
| { |
| log1("entering listen mode: %s", |
| new_mode != LISTEN_NONE |
| ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw") |
| : "none" |
| ); |
| |
| listen_mode = new_mode; |
| if (sockfd >= 0) { |
| close(sockfd); |
| sockfd = -1; |
| } |
| if (new_mode == LISTEN_KERNEL) |
| sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface); |
| else if (new_mode != LISTEN_NONE) |
| sockfd = udhcp_raw_socket(client_config.ifindex); |
| /* else LISTEN_NONE: sockfd stays closed */ |
| } |
| |
| /* Called only on SIGUSR1 */ |
| static void perform_renew(void) |
| { |
| bb_error_msg("performing DHCP renew"); |
| switch (state) { |
| case BOUND: |
| change_listen_mode(LISTEN_KERNEL); |
| case RENEWING: |
| case REBINDING: |
| state = RENEW_REQUESTED; |
| break; |
| case RENEW_REQUESTED: /* impatient are we? fine, square 1 */ |
| udhcp_run_script(NULL, "deconfig"); |
| case REQUESTING: |
| case RELEASED: |
| change_listen_mode(LISTEN_RAW); |
| state = INIT_SELECTING; |
| break; |
| case INIT_SELECTING: |
| break; |
| } |
| } |
| |
| static void perform_release(uint32_t server_addr, uint32_t requested_ip) |
| { |
| char buffer[sizeof("255.255.255.255")]; |
| struct in_addr temp_addr; |
| |
| /* send release packet */ |
| if (state == BOUND |
| || state == RENEWING |
| || state == REBINDING |
| || state == RENEW_REQUESTED |
| ) { |
| temp_addr.s_addr = server_addr; |
| strcpy(buffer, inet_ntoa(temp_addr)); |
| temp_addr.s_addr = requested_ip; |
| bb_error_msg("unicasting a release of %s to %s", |
| inet_ntoa(temp_addr), buffer); |
| send_release(server_addr, requested_ip); /* unicast */ |
| } |
| bb_error_msg("entering released state"); |
| /* |
| * We can be here on: SIGUSR2, |
| * or on exit (SIGTERM) and -R "release on quit" is specified. |
| * Users requested to be notified in all cases, even if not in one |
| * of the states above. |
| */ |
| udhcp_run_script(NULL, "deconfig"); |
| |
| change_listen_mode(LISTEN_NONE); |
| state = RELEASED; |
| } |
| |
| static uint8_t* alloc_dhcp_option(int code, const char *str, int extra) |
| { |
| uint8_t *storage; |
| int len = strnlen(str, 255); |
| storage = xzalloc(len + extra + OPT_DATA); |
| storage[OPT_CODE] = code; |
| storage[OPT_LEN] = len + extra; |
| memcpy(storage + extra + OPT_DATA, str, len); |
| return storage; |
| } |
| |
| #if BB_MMU |
| static void client_background(void) |
| { |
| bb_daemonize(0); |
| logmode &= ~LOGMODE_STDIO; |
| /* rewrite pidfile, as our pid is different now */ |
| write_pidfile(client_config.pidfile); |
| } |
| #endif |
| |
| //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 |
| //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__ |
| //usage:#else |
| //usage:# define IF_UDHCP_VERBOSE(...) |
| //usage:#endif |
| //usage:#define udhcpc_trivial_usage |
| //usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n" |
| //usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n" |
| //usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..." |
| //usage:#define udhcpc_full_usage "\n" |
| //usage: "\n -i IFACE Interface to use (default eth0)" |
| //usage: IF_FEATURE_UDHCP_PORT( |
| //usage: "\n -P PORT Use PORT (default 68)" |
| //usage: ) |
| //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")" |
| //usage: "\n -p FILE Create pidfile" |
| //usage: "\n -B Request broadcast replies" |
| //usage: "\n -t N Send up to N discover packets (default 3)" |
| //usage: "\n -T SEC Pause between packets (default 3)" |
| //usage: "\n -A SEC Wait if lease is not obtained (default 20)" |
| //usage: "\n -n Exit if lease is not obtained" |
| //usage: "\n -q Exit after obtaining lease" |
| //usage: "\n -R Release IP on exit" |
| //usage: "\n -f Run in foreground" |
| //usage: USE_FOR_MMU( |
| //usage: "\n -b Background if lease is not obtained" |
| //usage: ) |
| //usage: "\n -S Log to syslog too" |
| //usage: IF_FEATURE_UDHCPC_ARPING( |
| //usage: "\n -a[MSEC] Validate offered address with ARP ping" |
| //usage: ) |
| //usage: "\n -r IP Request this IP address" |
| //usage: "\n -o Don't request any options (unless -O is given)" |
| //usage: "\n -O OPT Request option OPT from server (cumulative)" |
| //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)" |
| //usage: "\n Examples of string, numeric, and hex byte opts:" |
| //usage: "\n -x hostname:bbox - option 12" |
| //usage: "\n -x lease:3600 - option 51 (lease time)" |
| //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)" |
| //usage: "\n -F NAME Ask server to update DNS mapping for NAME" |
| //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')" |
| //usage: "\n -C Don't send MAC as client identifier" |
| //usage: IF_UDHCP_VERBOSE( |
| //usage: "\n -v Verbose" |
| //usage: ) |
| //usage: "\nSignals:" |
| //usage: "\n USR1 Renew lease" |
| //usage: "\n USR2 Release lease" |
| |
| |
| int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int udhcpc_main(int argc UNUSED_PARAM, char **argv) |
| { |
| uint8_t *message; |
| const char *str_V, *str_h, *str_F, *str_r; |
| IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";) |
| IF_FEATURE_UDHCP_PORT(char *str_P;) |
| void *clientid_mac_ptr; |
| llist_t *list_O = NULL; |
| llist_t *list_x = NULL; |
| int tryagain_timeout = 20; |
| int discover_timeout = 3; |
| int discover_retries = 3; |
| uint32_t server_addr = server_addr; /* for compiler */ |
| uint32_t requested_ip = 0; |
| uint32_t xid = xid; /* for compiler */ |
| int packet_num; |
| int timeout; /* must be signed */ |
| unsigned already_waited_sec; |
| unsigned opt; |
| IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;) |
| int retval; |
| |
| setup_common_bufsiz(); |
| |
| /* Default options */ |
| IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;) |
| IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;) |
| client_config.interface = "eth0"; |
| client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT; |
| str_V = "udhcp "BB_VER; |
| |
| /* Parse command line */ |
| opt = getopt32long(argv, "^" |
| /* O,x: list; -T,-t,-A take numeric param */ |
| "CV:H:h:F:i:np:qRr:s:T:+t:+SA:+O:*ox:*fB" |
| USE_FOR_MMU("b") |
| IF_FEATURE_UDHCPC_ARPING("a::") |
| IF_FEATURE_UDHCP_PORT("P:") |
| "v" |
| "\0" IF_UDHCP_VERBOSE("vv") /* -v is a counter */ |
| , udhcpc_longopts |
| , &str_V, &str_h, &str_h, &str_F |
| , &client_config.interface, &client_config.pidfile /* i,p */ |
| , &str_r /* r */ |
| , &client_config.script /* s */ |
| , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */ |
| , &list_O |
| , &list_x |
| IF_FEATURE_UDHCPC_ARPING(, &str_a) |
| IF_FEATURE_UDHCP_PORT(, &str_P) |
| IF_UDHCP_VERBOSE(, &dhcp_verbose) |
| ); |
| if (opt & (OPT_h|OPT_H)) { |
| //msg added 2011-11 |
| bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME"); |
| client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0); |
| } |
| if (opt & OPT_F) { |
| /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */ |
| client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3); |
| /* Flag bits: 0000NEOS |
| * S: 1 = Client requests server to update A RR in DNS as well as PTR |
| * O: 1 = Server indicates to client that DNS has been updated regardless |
| * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>, |
| * not "host.domain.com". Format 0 is obsolete. |
| * N: 1 = Client requests server to not update DNS (S must be 0 then) |
| * Two [0] bytes which follow are deprecated and must be 0. |
| */ |
| client_config.fqdn[OPT_DATA + 0] = 0x1; |
| /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */ |
| /*client_config.fqdn[OPT_DATA + 2] = 0; */ |
| } |
| if (opt & OPT_r) |
| requested_ip = inet_addr(str_r); |
| #if ENABLE_FEATURE_UDHCP_PORT |
| if (opt & OPT_P) { |
| CLIENT_PORT = xatou16(str_P); |
| SERVER_PORT = CLIENT_PORT - 1; |
| } |
| #endif |
| IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);) |
| while (list_O) { |
| char *optstr = llist_pop(&list_O); |
| unsigned n = bb_strtou(optstr, NULL, 0); |
| if (errno || n > 254) { |
| n = udhcp_option_idx(optstr, dhcp_option_strings); |
| n = dhcp_optflags[n].code; |
| } |
| client_config.opt_mask[n >> 3] |= 1 << (n & 7); |
| } |
| if (!(opt & OPT_o)) { |
| unsigned i, n; |
| for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) { |
| if (dhcp_optflags[i].flags & OPTION_REQ) { |
| client_config.opt_mask[n >> 3] |= 1 << (n & 7); |
| } |
| } |
| } |
| while (list_x) { |
| char *optstr = llist_pop(&list_x); |
| char *colon = strchr(optstr, ':'); |
| if (colon) |
| *colon = ' '; |
| /* now it looks similar to udhcpd's config file line: |
| * "optname optval", using the common routine: */ |
| udhcp_str2optset(optstr, &client_config.options, dhcp_optflags, dhcp_option_strings); |
| if (colon) |
| *colon = ':'; /* restore it for NOMMU reexec */ |
| } |
| |
| if (udhcp_read_interface(client_config.interface, |
| &client_config.ifindex, |
| NULL, |
| client_config.client_mac) |
| ) { |
| return 1; |
| } |
| |
| clientid_mac_ptr = NULL; |
| if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) { |
| /* not suppressed and not set, set the default client ID */ |
| client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7); |
| client_config.clientid[OPT_DATA] = 1; /* type: ethernet */ |
| clientid_mac_ptr = client_config.clientid + OPT_DATA+1; |
| memcpy(clientid_mac_ptr, client_config.client_mac, 6); |
| } |
| if (str_V[0] != '\0') { |
| // can drop -V, str_V, client_config.vendorclass, |
| // but need to add "vendor" to the list of recognized |
| // string opts for this to work; |
| // and need to tweak add_client_options() too... |
| // ...so the question is, should we? |
| //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR"); |
| client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0); |
| } |
| |
| #if !BB_MMU |
| /* on NOMMU reexec (i.e., background) early */ |
| if (!(opt & OPT_f)) { |
| bb_daemonize_or_rexec(0 /* flags */, argv); |
| logmode = LOGMODE_NONE; |
| } |
| #endif |
| if (opt & OPT_S) { |
| openlog(applet_name, LOG_PID, LOG_DAEMON); |
| logmode |= LOGMODE_SYSLOG; |
| } |
| |
| /* Make sure fd 0,1,2 are open */ |
| bb_sanitize_stdio(); |
| /* Create pidfile */ |
| write_pidfile(client_config.pidfile); |
| /* Goes to stdout (unless NOMMU) and possibly syslog */ |
| bb_error_msg("started, v"BB_VER); |
| /* Set up the signal pipe */ |
| udhcp_sp_setup(); |
| /* We want random_xid to be random... */ |
| srand(monotonic_us()); |
| |
| state = INIT_SELECTING; |
| udhcp_run_script(NULL, "deconfig"); |
| change_listen_mode(LISTEN_RAW); |
| packet_num = 0; |
| timeout = 0; |
| already_waited_sec = 0; |
| |
| /* Main event loop. select() waits on signal pipe and possibly |
| * on sockfd. |
| * "continue" statements in code below jump to the top of the loop. |
| */ |
| for (;;) { |
| int tv; |
| struct pollfd pfds[2]; |
| struct dhcp_packet packet; |
| /* silence "uninitialized!" warning */ |
| unsigned timestamp_before_wait = timestamp_before_wait; |
| |
| //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode); |
| |
| /* Was opening raw or udp socket here |
| * if (listen_mode != LISTEN_NONE && sockfd < 0), |
| * but on fast network renew responses return faster |
| * than we open sockets. Thus this code is moved |
| * to change_listen_mode(). Thus we open listen socket |
| * BEFORE we send renew request (see "case BOUND:"). */ |
| |
| udhcp_sp_fd_set(pfds, sockfd); |
| |
| tv = timeout - already_waited_sec; |
| retval = 0; |
| /* If we already timed out, fall through with retval = 0, else... */ |
| if (tv > 0) { |
| log1("waiting %u seconds", tv); |
| timestamp_before_wait = (unsigned)monotonic_sec(); |
| retval = poll(pfds, 2, tv < INT_MAX/1000 ? tv * 1000 : INT_MAX); |
| if (retval < 0) { |
| /* EINTR? A signal was caught, don't panic */ |
| if (errno == EINTR) { |
| already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait; |
| continue; |
| } |
| /* Else: an error occurred, panic! */ |
| bb_perror_msg_and_die("poll"); |
| } |
| } |
| |
| /* If timeout dropped to zero, time to become active: |
| * resend discover/renew/whatever |
| */ |
| if (retval == 0) { |
| /* When running on a bridge, the ifindex may have changed |
| * (e.g. if member interfaces were added/removed |
| * or if the status of the bridge changed). |
| * Refresh ifindex and client_mac: |
| */ |
| if (udhcp_read_interface(client_config.interface, |
| &client_config.ifindex, |
| NULL, |
| client_config.client_mac) |
| ) { |
| goto ret0; /* iface is gone? */ |
| } |
| if (clientid_mac_ptr) |
| memcpy(clientid_mac_ptr, client_config.client_mac, 6); |
| |
| /* We will restart the wait in any case */ |
| already_waited_sec = 0; |
| |
| switch (state) { |
| case INIT_SELECTING: |
| if (!discover_retries || packet_num < discover_retries) { |
| if (packet_num == 0) |
| xid = random_xid(); |
| /* broadcast */ |
| send_discover(xid, requested_ip); |
| timeout = discover_timeout; |
| packet_num++; |
| continue; |
| } |
| leasefail: |
| udhcp_run_script(NULL, "leasefail"); |
| #if BB_MMU /* -b is not supported on NOMMU */ |
| if (opt & OPT_b) { /* background if no lease */ |
| bb_error_msg("no lease, forking to background"); |
| client_background(); |
| /* do not background again! */ |
| opt = ((opt & ~OPT_b) | OPT_f); |
| } else |
| #endif |
| if (opt & OPT_n) { /* abort if no lease */ |
| bb_error_msg("no lease, failing"); |
| retval = 1; |
| goto ret; |
| } |
| /* wait before trying again */ |
| timeout = tryagain_timeout; |
| packet_num = 0; |
| continue; |
| case REQUESTING: |
| if (packet_num < 3) { |
| /* send broadcast select packet */ |
| send_select(xid, server_addr, requested_ip); |
| timeout = discover_timeout; |
| packet_num++; |
| continue; |
| } |
| /* Timed out, go back to init state. |
| * "discover...select...discover..." loops |
| * were seen in the wild. Treat them similarly |
| * to "no response to discover" case */ |
| change_listen_mode(LISTEN_RAW); |
| state = INIT_SELECTING; |
| goto leasefail; |
| case BOUND: |
| /* 1/2 lease passed, enter renewing state */ |
| state = RENEWING; |
| client_config.first_secs = 0; /* make secs field count from 0 */ |
| change_listen_mode(LISTEN_KERNEL); |
| log1("entering renew state"); |
| /* fall right through */ |
| case RENEW_REQUESTED: /* manual (SIGUSR1) renew */ |
| case_RENEW_REQUESTED: |
| case RENEWING: |
| if (timeout > 60) { |
| /* send an unicast renew request */ |
| /* Sometimes observed to fail (EADDRNOTAVAIL) to bind |
| * a new UDP socket for sending inside send_renew. |
| * I hazard to guess existing listening socket |
| * is somehow conflicting with it, but why is it |
| * not deterministic then?! Strange. |
| * Anyway, it does recover by eventually failing through |
| * into INIT_SELECTING state. |
| */ |
| if (send_renew(xid, server_addr, requested_ip) >= 0) { |
| timeout >>= 1; |
| //TODO: the timeout to receive an answer for our renew should not be selected |
| //with "timeout = lease_seconds / 2; ...; timeout = timeout / 2": it is often huge. |
| //Waiting e.g. 4*3600 seconds for a reply does not make sense |
| //(if reply isn't coming, we keep an open socket for hours), |
| //it should be something like 10 seconds. |
| //Also, it's probably best to try sending renew in kernel mode a few (3-5) times |
| //and fall back to raw mode if it does not work. |
| continue; |
| } |
| /* else: error sending. |
| * example: ENETUNREACH seen with server |
| * which gave us bogus server ID 1.1.1.1 |
| * which wasn't reachable (and probably did not exist). |
| */ |
| } |
| /* Timed out or error, enter rebinding state */ |
| log1("entering rebinding state"); |
| state = REBINDING; |
| /* fall right through */ |
| case REBINDING: |
| /* Switch to bcast receive */ |
| change_listen_mode(LISTEN_RAW); |
| /* Lease is *really* about to run out, |
| * try to find DHCP server using broadcast */ |
| if (timeout > 0) { |
| /* send a broadcast renew request */ |
| send_renew(xid, 0 /*INADDR_ANY*/, requested_ip); |
| timeout >>= 1; |
| continue; |
| } |
| /* Timed out, enter init state */ |
| bb_error_msg("lease lost, entering init state"); |
| udhcp_run_script(NULL, "deconfig"); |
| state = INIT_SELECTING; |
| client_config.first_secs = 0; /* make secs field count from 0 */ |
| /*timeout = 0; - already is */ |
| packet_num = 0; |
| continue; |
| /* case RELEASED: */ |
| } |
| /* yah, I know, *you* say it would never happen */ |
| timeout = INT_MAX; |
| continue; /* back to main loop */ |
| } /* if select timed out */ |
| |
| /* select() didn't timeout, something happened */ |
| |
| /* Is it a signal? */ |
| /* note: udhcp_sp_read checks poll result before reading */ |
| switch (udhcp_sp_read(pfds)) { |
| case SIGUSR1: |
| client_config.first_secs = 0; /* make secs field count from 0 */ |
| already_waited_sec = 0; |
| perform_renew(); |
| if (state == RENEW_REQUESTED) { |
| /* We might be either on the same network |
| * (in which case renew might work), |
| * or we might be on a completely different one |
| * (in which case renew won't ever succeed). |
| * For the second case, must make sure timeout |
| * is not too big, or else we can send |
| * futile renew requests for hours. |
| * (Ab)use -A TIMEOUT value (usually 20 sec) |
| * as a cap on the timeout. |
| */ |
| if (timeout > tryagain_timeout) |
| timeout = tryagain_timeout; |
| goto case_RENEW_REQUESTED; |
| } |
| /* Start things over */ |
| packet_num = 0; |
| /* Kill any timeouts, user wants this to hurry along */ |
| timeout = 0; |
| continue; |
| case SIGUSR2: |
| perform_release(server_addr, requested_ip); |
| timeout = INT_MAX; |
| continue; |
| case SIGTERM: |
| bb_error_msg("received %s", "SIGTERM"); |
| goto ret0; |
| } |
| |
| /* Is it a packet? */ |
| if (listen_mode == LISTEN_NONE || !pfds[1].revents) |
| continue; /* no */ |
| |
| { |
| int len; |
| |
| /* A packet is ready, read it */ |
| if (listen_mode == LISTEN_KERNEL) |
| len = udhcp_recv_kernel_packet(&packet, sockfd); |
| else |
| len = udhcp_recv_raw_packet(&packet, sockfd); |
| if (len == -1) { |
| /* Error is severe, reopen socket */ |
| bb_error_msg("read error: "STRERROR_FMT", reopening socket" STRERROR_ERRNO); |
| sleep(discover_timeout); /* 3 seconds by default */ |
| change_listen_mode(listen_mode); /* just close and reopen */ |
| } |
| /* If this packet will turn out to be unrelated/bogus, |
| * we will go back and wait for next one. |
| * Be sure timeout is properly decreased. */ |
| already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait; |
| if (len < 0) |
| continue; |
| } |
| |
| if (packet.xid != xid) { |
| log1("xid %x (our is %x), ignoring packet", |
| (unsigned)packet.xid, (unsigned)xid); |
| continue; |
| } |
| |
| /* Ignore packets that aren't for us */ |
| if (packet.hlen != 6 |
| || memcmp(packet.chaddr, client_config.client_mac, 6) != 0 |
| ) { |
| //FIXME: need to also check that last 10 bytes are zero |
| log1("chaddr does not match, ignoring packet"); // log2? |
| continue; |
| } |
| |
| message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE); |
| if (message == NULL) { |
| bb_error_msg("no message type option, ignoring packet"); |
| continue; |
| } |
| |
| switch (state) { |
| case INIT_SELECTING: |
| /* Must be a DHCPOFFER */ |
| if (*message == DHCPOFFER) { |
| uint8_t *temp; |
| |
| /* What exactly is server's IP? There are several values. |
| * Example DHCP offer captured with tchdump: |
| * |
| * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src |
| * BOOTP fields: |
| * Your-IP 10.34.25.202 |
| * Server-IP 10.34.32.125 // "next server" IP |
| * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use) |
| * DHCP options: |
| * DHCP-Message Option 53, length 1: Offer |
| * Server-ID Option 54, length 4: 10.34.255.7 // "server ID" |
| * Default-Gateway Option 3, length 4: 10.34.25.254 // router |
| * |
| * We think that real server IP (one to use in renew/release) |
| * is one in Server-ID option. But I am not 100% sure. |
| * IP header's src and Gateway-IP (same in this example) |
| * might work too. |
| * "Next server" and router are definitely wrong ones to use, though... |
| */ |
| /* We used to ignore pcakets without DHCP_SERVER_ID. |
| * I've got user reports from people who run "address-less" servers. |
| * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all. |
| * They say ISC DHCP client supports this case. |
| */ |
| server_addr = 0; |
| temp = udhcp_get_option(&packet, DHCP_SERVER_ID); |
| if (!temp) { |
| bb_error_msg("no server ID, using 0.0.0.0"); |
| } else { |
| /* it IS unaligned sometimes, don't "optimize" */ |
| move_from_unaligned32(server_addr, temp); |
| } |
| /*xid = packet.xid; - already is */ |
| requested_ip = packet.yiaddr; |
| |
| /* enter requesting state */ |
| state = REQUESTING; |
| timeout = 0; |
| packet_num = 0; |
| already_waited_sec = 0; |
| } |
| continue; |
| case REQUESTING: |
| case RENEWING: |
| case RENEW_REQUESTED: |
| case REBINDING: |
| if (*message == DHCPACK) { |
| unsigned start; |
| uint32_t lease_seconds; |
| struct in_addr temp_addr; |
| uint8_t *temp; |
| |
| temp = udhcp_get_option(&packet, DHCP_LEASE_TIME); |
| if (!temp) { |
| bb_error_msg("no lease time with ACK, using 1 hour lease"); |
| lease_seconds = 60 * 60; |
| } else { |
| /* it IS unaligned sometimes, don't "optimize" */ |
| move_from_unaligned32(lease_seconds, temp); |
| lease_seconds = ntohl(lease_seconds); |
| /* paranoia: must not be too small and not prone to overflows */ |
| if (lease_seconds < 0x10) |
| lease_seconds = 0x10; |
| //if (lease_seconds > 0x7fffffff) |
| // lease_seconds = 0x7fffffff; |
| //^^^not necessary since "timeout = lease_seconds / 2" |
| //does not overflow even for 0xffffffff. |
| } |
| #if ENABLE_FEATURE_UDHCPC_ARPING |
| if (opt & OPT_a) { |
| /* RFC 2131 3.1 paragraph 5: |
| * "The client receives the DHCPACK message with configuration |
| * parameters. The client SHOULD perform a final check on the |
| * parameters (e.g., ARP for allocated network address), and notes |
| * the duration of the lease specified in the DHCPACK message. At this |
| * point, the client is configured. If the client detects that the |
| * address is already in use (e.g., through the use of ARP), |
| * the client MUST send a DHCPDECLINE message to the server and restarts |
| * the configuration process..." */ |
| if (!arpping(packet.yiaddr, |
| NULL, |
| (uint32_t) 0, |
| client_config.client_mac, |
| client_config.interface, |
| arpping_ms) |
| ) { |
| bb_error_msg("offered address is in use " |
| "(got ARP reply), declining"); |
| send_decline(/*xid,*/ server_addr, packet.yiaddr); |
| |
| if (state != REQUESTING) |
| udhcp_run_script(NULL, "deconfig"); |
| change_listen_mode(LISTEN_RAW); |
| state = INIT_SELECTING; |
| client_config.first_secs = 0; /* make secs field count from 0 */ |
| requested_ip = 0; |
| timeout = tryagain_timeout; |
| packet_num = 0; |
| already_waited_sec = 0; |
| continue; /* back to main loop */ |
| } |
| } |
| #endif |
| /* enter bound state */ |
| temp_addr.s_addr = packet.yiaddr; |
| bb_error_msg("lease of %s obtained, lease time %u", |
| inet_ntoa(temp_addr), (unsigned)lease_seconds); |
| requested_ip = packet.yiaddr; |
| |
| start = monotonic_sec(); |
| udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew"); |
| already_waited_sec = (unsigned)monotonic_sec() - start; |
| timeout = lease_seconds / 2; |
| if ((unsigned)timeout < already_waited_sec) { |
| /* Something went wrong. Back to discover state */ |
| timeout = already_waited_sec = 0; |
| } |
| |
| state = BOUND; |
| change_listen_mode(LISTEN_NONE); |
| if (opt & OPT_q) { /* quit after lease */ |
| goto ret0; |
| } |
| /* future renew failures should not exit (JM) */ |
| opt &= ~OPT_n; |
| #if BB_MMU /* NOMMU case backgrounded earlier */ |
| if (!(opt & OPT_f)) { |
| client_background(); |
| /* do not background again! */ |
| opt = ((opt & ~OPT_b) | OPT_f); |
| } |
| #endif |
| /* make future renew packets use different xid */ |
| /* xid = random_xid(); ...but why bother? */ |
| |
| continue; /* back to main loop */ |
| } |
| if (*message == DHCPNAK) { |
| /* If network has more than one DHCP server, |
| * "wrong" server can reply first, with a NAK. |
| * Do not interpret it as a NAK from "our" server. |
| */ |
| if (server_addr != 0) { |
| uint32_t svid; |
| uint8_t *temp; |
| |
| temp = udhcp_get_option(&packet, DHCP_SERVER_ID); |
| if (!temp) { |
| non_matching_svid: |
| log1("received DHCP NAK with wrong" |
| " server ID, ignoring packet"); |
| continue; |
| } |
| move_from_unaligned32(svid, temp); |
| if (svid != server_addr) |
| goto non_matching_svid; |
| } |
| /* return to init state */ |
| bb_error_msg("received %s", "DHCP NAK"); |
| udhcp_run_script(&packet, "nak"); |
| if (state != REQUESTING) |
| udhcp_run_script(NULL, "deconfig"); |
| change_listen_mode(LISTEN_RAW); |
| sleep(3); /* avoid excessive network traffic */ |
| state = INIT_SELECTING; |
| client_config.first_secs = 0; /* make secs field count from 0 */ |
| requested_ip = 0; |
| timeout = 0; |
| packet_num = 0; |
| already_waited_sec = 0; |
| } |
| continue; |
| /* case BOUND: - ignore all packets */ |
| /* case RELEASED: - ignore all packets */ |
| } |
| /* back to main loop */ |
| } /* for (;;) - main loop ends */ |
| |
| ret0: |
| if (opt & OPT_R) /* release on quit */ |
| perform_release(server_addr, requested_ip); |
| retval = 0; |
| ret: |
| /*if (client_config.pidfile) - remove_pidfile has its own check */ |
| remove_pidfile(client_config.pidfile); |
| return retval; |
| } |