X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fdhcpc.c;h=8dee916d9892cdb6d2eb249916109a8ccff9478c;hb=cb1dc1d1d1c0132636454ecfdb6cac3eade323e6;hp=fe8f4c8fa9cb2d3e3e29a3855a3bba9270af3e3d;hpb=1d42665b6b0571b9fa5d3b10fbf2dd03382f0ba2;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index fe8f4c8fa..8dee916d9 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -1,53 +1,1079 @@ /* vi: set sw=4 ts=4: */ -/* dhcpc.c - * - * udhcp DHCP client +/* + * udhcp client * * Russ Dill July 2001 * - * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. + * 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. */ - -#include #include - /* 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 "options.h" +#include +#include +#include + +/* "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" + "background\0" No_argument "b" + "broadcast\0" No_argument "B" + IF_FEATURE_UDHCPC_ARPING("arping\0" No_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[] = { + [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("32 128 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; +} + +/* 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 (pos == 0) { + /* label must begin with letter */ + return NULL; + } + 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++; + } +} + +/* 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 - 1) / (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 differn 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) +{ + return udhcp_send_raw_packet(packet, + /*src*/ INADDR_ANY, 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) + return udhcp_send_kernel_packet(packet, + ciaddr, CLIENT_PORT, + server, SERVER_PORT); + return raw_bcast_from_client_config_ifindex(packet); +} + +/* 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_info_msg("Sending discover..."); + return raw_bcast_from_client_config_ifindex(&packet); +} + +/* 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 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); + + addr.s_addr = requested; + bb_info_msg("Sending select for %s...", inet_ntoa(addr)); + return raw_bcast_from_client_config_ifindex(&packet); +} + +/* 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; + +/* + * 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); + + bb_info_msg("Sending renew..."); + 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_info_msg("Sending decline..."); + return raw_bcast_from_client_config_ifindex(&packet); +} +#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_info_msg("Sending 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_info_msg("Packet with bad magic, ignoring"); + return -2; + } + + log1("Received 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 timeout; /* = 0. Must be signed */ -static uint32_t requested_ip; /* = 0 */ -static uint32_t server_addr; static int sockfd = -1; -#define LISTEN_NONE 0 +#define LISTEN_NONE 0 #define LISTEN_KERNEL 1 -#define LISTEN_RAW 2 +#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; -/* struct client_config_t client_config is in bb_common_bufsiz1 */ +static int udhcp_raw_socket(int ifindex) +{ + int fd; + struct sockaddr_ll sock; + + /* + * Comment: + * + * 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 . + * License: GPL v2. + * + * TODO: make conditional? + */ + 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 */ + BPF_STMT(BPF_RET|BPF_K, 0xffffffff), + /* L4: discard packet */ + 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, + }; + + log1("Opening raw socket on ifindex %d", ifindex); //log2? + + fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP)); + log1("Got raw socket fd"); //log2? + + sock.sll_family = AF_PACKET; + sock.sll_protocol = htons(ETH_P_IP); + sock.sll_ifindex = ifindex; + xbind(fd, (struct sockaddr *) &sock, sizeof(sock)); + + if (CLIENT_PORT == 68) { + /* Use only if standard port is in use */ + /* 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? + } + + if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA, + &const_int_1, sizeof(int)) < 0 + ) { + if (errno != ENOPROTOOPT) + log1("Can't set PACKET_AUXDATA on raw socket"); + } + log1("Created raw socket"); + + return fd; +} -/* just a little helper */ static void change_listen_mode(int new_mode) { - DEBUG("entering %s listen mode", - new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none"); + 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; } - listen_mode = new_mode; + 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 */ } - -/* perform a renew */ +/* Called only on SIGUSR1 */ static void perform_renew(void) { bb_info_msg("Performing a DHCP renew"); @@ -70,9 +1096,7 @@ static void perform_renew(void) } } - -/* perform a release */ -static void perform_release(void) +static void perform_release(uint32_t server_addr, uint32_t requested_ip) { char buffer[sizeof("255.255.255.255")]; struct in_addr temp_addr; @@ -91,35 +1115,12 @@ static void perform_release(void) change_listen_mode(LISTEN_NONE); state = RELEASED; - timeout = INT_MAX; -} - - -static void client_background(void) -{ -#if !BB_MMU - bb_error_msg("cannot background in uclinux (yet)"); -/* ... mainly because udhcpc calls client_background() - * in _the _middle _of _udhcpc _run_, not at the start! - * If that will be properly disabled for NOMMU, client_background() - * will work on NOMMU too */ -#else - bb_daemonize(0); - logmode &= ~LOGMODE_STDIO; - /* rewrite pidfile, as our pid is different now */ - write_pidfile(client_config.pidfile); -#endif - /* Do not fork again. */ - client_config.foreground = 1; - client_config.background_if_no_lease = 0; } - static uint8_t* alloc_dhcp_option(int code, const char *str, int extra) { uint8_t *storage; - int len = strlen(str); - if (len > 255) len = 255; + int len = strnlen(str, 255); storage = xzalloc(len + extra + OPT_DATA); storage[OPT_CODE] = code; storage[OPT_LEN] = len + extra; @@ -127,165 +1128,175 @@ static uint8_t* alloc_dhcp_option(int code, const char *str, int extra) 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")IF_FEATURE_UDHCPC_ARPING("a")"RB] [-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: IF_LONG_OPTS( +//usage: "\n -i,--interface IFACE Interface to use (default eth0)" +//usage: IF_FEATURE_UDHCP_PORT( +//usage: "\n -P,--client-port PORT Use PORT (default 68)" +//usage: ) +//usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")" +//usage: "\n -p,--pidfile FILE Create pidfile" +//usage: "\n -B,--broadcast Request broadcast replies" +//usage: "\n -t,--retries N Send up to N discover packets (default 3)" +//usage: "\n -T,--timeout SEC Pause between packets (default 3)" +//usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)" +//usage: "\n -n,--now Exit if lease is not obtained" +//usage: "\n -q,--quit Exit after obtaining lease" +//usage: "\n -R,--release Release IP on exit" +//usage: "\n -f,--foreground Run in foreground" +//usage: USE_FOR_MMU( +//usage: "\n -b,--background Background if lease is not obtained" +//usage: ) +//usage: "\n -S,--syslog Log to syslog too" +//usage: IF_FEATURE_UDHCPC_ARPING( +//usage: "\n -a,--arping Use arping to validate offered address" +//usage: ) +//usage: "\n -r,--request IP Request this IP address" +//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)" +//usage: "\n -O,--request-option 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,--fqdn NAME Ask server to update DNS mapping for NAME" +//usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')" +//usage: "\n -C,--clientid-none Don't send MAC as client identifier" +//usage: IF_UDHCP_VERBOSE( +//usage: "\n -v Verbose" +//usage: ) +//usage: ) +//usage: IF_NOT_LONG_OPTS( +//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 Use arping to validate offered address" +//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: ) +//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 ATTRIBUTE_UNUSED, char **argv) +int udhcpc_main(int argc UNUSED_PARAM, char **argv) { uint8_t *temp, *message; - char *str_c, *str_V, *str_h, *str_F, *str_r; - USE_FEATURE_UDHCP_PORT(char *str_P;) + const char *str_V, *str_h, *str_F, *str_r; + IF_FEATURE_UDHCP_PORT(char *str_P;) + void *clientid_mac_ptr; llist_t *list_O = NULL; -#if ENABLE_FEATURE_UDHCPC_ARPING - char *str_W; -#endif + llist_t *list_x = NULL; int tryagain_timeout = 20; int discover_timeout = 3; int discover_retries = 3; - uint32_t xid = 0; - uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */ + uint32_t server_addr = server_addr; /* for compiler */ + uint32_t requested_ip = 0; + uint32_t xid = xid; /* for compiler */ int packet_num; - /* t1, t2... what a wonderful names... */ - unsigned t1 = t1; /* for gcc */ - unsigned t2 = t2; - unsigned timestamp_got_lease = timestamp_got_lease; + int timeout; /* must be signed */ + unsigned already_waited_sec; unsigned opt; int max_fd; int retval; - int len; - struct timeval tv; - struct in_addr temp_addr; - struct dhcpMessage packet; fd_set rfds; - enum { - OPT_c = 1 << 0, - OPT_C = 1 << 1, - OPT_V = 1 << 2, - OPT_f = 1 << 3, - OPT_b = 1 << 4, - OPT_H = 1 << 5, - OPT_h = 1 << 6, - OPT_F = 1 << 7, - OPT_i = 1 << 8, - OPT_n = 1 << 9, - OPT_p = 1 << 10, - OPT_q = 1 << 11, - OPT_R = 1 << 12, - OPT_r = 1 << 13, - OPT_s = 1 << 14, - OPT_T = 1 << 15, - OPT_t = 1 << 16, - OPT_v = 1 << 17, - OPT_S = 1 << 18, - OPT_A = 1 << 19, -#if ENABLE_FEATURE_UDHCPC_ARPING - OPT_a = 1 << 20, - OPT_W = 1 << 21, -#endif - OPT_P = 1 << 22, - }; -#if ENABLE_GETOPT_LONG - static const char udhcpc_longopts[] ALIGN1 = - "clientid\0" Required_argument "c" - "clientid-none\0" No_argument "C" - "vendorclass\0" Required_argument "V" - "foreground\0" No_argument "f" - "background\0" No_argument "b" - "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" - "version\0" No_argument "v" - "retries\0" Required_argument "t" - "tryagain\0" Required_argument "A" - "syslog\0" No_argument "S" -#if ENABLE_FEATURE_UDHCPC_ARPING - "arping\0" No_argument "a" -#endif - "request-option\0" Required_argument "O" -#if ENABLE_FEATURE_UDHCP_PORT - "client-port\0" Required_argument "P" -#endif - ; -#endif - /* Default options. */ -#if ENABLE_FEATURE_UDHCP_PORT - SERVER_PORT = 67; - CLIENT_PORT = 68; -#endif + /* Default options */ + IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;) + IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;) client_config.interface = "eth0"; - client_config.script = DEFAULT_SCRIPT; + client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT; + str_V = "udhcp "BB_VER; /* Parse command line */ - /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */ - opt_complementary = "c--C:C--c:O::T+:t+:A+"; -#if ENABLE_GETOPT_LONG - applet_long_options = udhcpc_longopts; -#endif - opt = getopt32(argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:vSA:" - USE_FEATURE_UDHCPC_ARPING("aW:") - USE_FEATURE_UDHCP_PORT("P:") - "O:" - , &str_c, &str_V, &str_h, &str_h, &str_F - , &client_config.interface, &client_config.pidfile, &str_r - , &client_config.script - , &discover_timeout, &discover_retries, &tryagain_timeout - USE_FEATURE_UDHCPC_ARPING(, &str_W) - USE_FEATURE_UDHCP_PORT(, &str_P) + /* O,x: list; -T,-t,-A take numeric param */ + opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ; + IF_LONG_OPTS(applet_long_options = udhcpc_longopts;) + opt = getopt32(argv, "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" + , &str_V, &str_h, &str_h, &str_F + , &client_config.interface, &client_config.pidfile, &str_r /* i,p */ + , &client_config.script /* s */ + , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */ , &list_O - ); - - if (opt & OPT_c) - client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0); - //if (opt & OPT_C) - if (opt & OPT_V) - client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0); - if (opt & OPT_f) - client_config.foreground = 1; - if (opt & OPT_b) - client_config.background_if_no_lease = 1; - if (opt & (OPT_h|OPT_H)) + , &list_x + 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] */ client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3); - /* Flags: 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 data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com" - N: 1 => Client requests Server to not update DNS - */ + /* 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; - redundant */ - /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */ - } - // if (opt & OPT_i) client_config.interface = ... - if (opt & OPT_n) - client_config.abort_if_no_lease = 1; - // if (opt & OPT_p) client_config.pidfile = ... - if (opt & OPT_q) - client_config.quit_after_lease = 1; - if (opt & OPT_R) - client_config.release_on_quit = 1; + /*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 (opt & OPT_s) client_config.script = ... - // if (opt & OPT_T) discover_timeout = xatoi_u(str_T); - // if (opt & OPT_t) discover_retries = xatoi_u(str_t); - // if (opt & OPT_A) tryagain_timeout = xatoi_u(str_A); - if (opt & OPT_v) { - puts("version "BB_VER); - return 0; - } - if (opt & OPT_S) { - openlog(applet_name, LOG_PID, LOG_LOCAL0); - logmode |= LOGMODE_SYSLOG; - } #if ENABLE_FEATURE_UDHCP_PORT if (opt & OPT_P) { CLIENT_PORT = xatou16(str_P); @@ -293,165 +1304,242 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) } #endif while (list_O) { - int n = index_in_strings(dhcp_option_strings, list_O->data); - if (n < 0) - bb_error_msg_and_die("unknown option '%s'", list_O->data); - n = dhcp_options[n].code; + char *optstr = llist_pop(&list_O); + unsigned n = bb_strtou(optstr, NULL, 0); + if (errno || n > 254) { + n = udhcp_option_idx(optstr); + n = dhcp_optflags[n].code; + } client_config.opt_mask[n >> 3] |= 1 << (n & 7); - list_O = list_O->link; + } + 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); } - if (read_interface(client_config.interface, &client_config.ifindex, - NULL, client_config.arp)) + 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(); /* Equivalent of doing a fflush after every \n */ setlinebuf(stdout); - /* Create pidfile */ write_pidfile(client_config.pidfile); - /* if (!..) bb_perror_msg("cannot create pidfile %s", pidfile); */ - - /* Goes to stdout and possibly syslog */ + /* Goes to stdout (unless NOMMU) and possibly syslog */ bb_info_msg("%s (v"BB_VER") started", applet_name); - - /* if not set, and not suppressed, setup the default client ID */ - if (!client_config.clientid && !(opt & OPT_C)) { - client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7); - client_config.clientid[OPT_DATA] = 1; - memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6); - } - - if (!client_config.vendorclass) - client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0); - - /* setup the signal pipe */ + /* 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 (;;) { - tv.tv_sec = timeout; - tv.tv_usec = 0; + struct timeval tv; + 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:"). */ - if (listen_mode != LISTEN_NONE && sockfd < 0) { - if (listen_mode == LISTEN_KERNEL) - sockfd = listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface); - else - sockfd = raw_socket(client_config.ifindex); - } max_fd = udhcp_sp_fd_set(&rfds, sockfd); - retval = 0; /* If we already timed out, fall through, else... */ - if (tv.tv_sec > 0) { - DEBUG("Waiting on select..."); + tv.tv_sec = timeout - already_waited_sec; + tv.tv_usec = 0; + retval = 0; + /* If we already timed out, fall through with retval = 0, else... */ + if ((int)tv.tv_sec > 0) { + log1("Waiting on select %u seconds", (int)tv.tv_sec); + timestamp_before_wait = (unsigned)monotonic_sec(); retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); - } - - if (retval < 0) { - /* EINTR? signal was caught, don't panic */ - if (errno != EINTR) { + 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 occured, panic! */ bb_perror_msg_and_die("select"); } - continue; } /* 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 (packet_num < discover_retries) { + if (!discover_retries || packet_num < discover_retries) { if (packet_num == 0) xid = random_xid(); - - /* send discover packet */ - send_discover(xid, requested_ip); /* broadcast */ - + /* broadcast */ + send_discover(xid, requested_ip); timeout = discover_timeout; packet_num++; continue; } + leasefail: udhcp_run_script(NULL, "leasefail"); - if (client_config.background_if_no_lease) { +#if BB_MMU /* -b is not supported on NOMMU */ + if (opt & OPT_b) { /* background if no lease */ bb_info_msg("No lease, forking to background"); client_background(); - } else if (client_config.abort_if_no_lease) { + /* do not background again! */ + opt = ((opt & ~OPT_b) | OPT_f); + } else +#endif + if (opt & OPT_n) { /* abort if no lease */ bb_info_msg("No lease, failing"); retval = 1; goto ret; } - /* wait to try again */ + /* wait before trying again */ timeout = tryagain_timeout; packet_num = 0; continue; - case RENEW_REQUESTED: case REQUESTING: - if (packet_num < discover_retries) { - /* send request packet */ - if (state == RENEW_REQUESTED) - send_renew(xid, server_addr, requested_ip); /* unicast */ - else send_selecting(xid, server_addr, requested_ip); /* broadcast */ - - timeout = ((packet_num == 2) ? 10 : 2); + if (!discover_retries || packet_num < discover_retries) { + /* send broadcast select packet */ + send_select(xid, server_addr, requested_ip); + timeout = discover_timeout; packet_num++; continue; } - /* timed out, go back to init state */ - if (state == RENEW_REQUESTED) - udhcp_run_script(NULL, "deconfig"); + /* 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; - timeout = 0; - packet_num = 0; - continue; + goto leasefail; case BOUND: - /* Lease is starting to run out, time to enter renewing state */ - change_listen_mode(LISTEN_KERNEL); - DEBUG("Entering renew state"); + /* 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: - /* Either set a new T1, or enter REBINDING state */ - if ((t2 - t1) > (lease_seconds / (4*60*60) + 1)) { - /* send a request packet */ - send_renew(xid, server_addr, requested_ip); /* unicast */ - t1 += (t2 - t1) / 2; - timeout = t1 - ((int)monotonic_sec() - timestamp_got_lease); + 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. + */ + send_renew(xid, server_addr, requested_ip); + timeout >>= 1; continue; } /* Timed out, enter rebinding state */ - DEBUG("Entering rebinding state"); + log1("Entering rebinding state"); state = REBINDING; - timeout = (t2 - t1); - continue; + /* 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 ((lease_seconds - t2) > (lease_seconds / (4*60*60) + 1)) { - /* send a request packet */ - send_renew(xid, 0, requested_ip); /* broadcast */ - t2 += (lease_seconds - t2) / 2; - timeout = t2 - ((int)monotonic_sec() - timestamp_got_lease); + 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_info_msg("Lease lost, entering init state"); udhcp_run_script(NULL, "deconfig"); - change_listen_mode(LISTEN_RAW); state = INIT_SELECTING; - timeout = 0; + client_config.first_secs = 0; /* make secs field count from 0 */ + /*timeout = 0; - already is */ packet_num = 0; continue; /* case RELEASED: */ @@ -459,173 +1547,250 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) /* 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 FD_ISSET before reading */ + switch (udhcp_sp_read(&rfds)) { + 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_info_msg("Received SIGTERM"); + goto ret0; } - /* select() didn't timeout, something did happen. */ - /* Is is a packet? */ - if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) { - /* A packet is ready, read it */ + /* Is it a packet? */ + if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds)) + continue; /* no */ + { + int len; + + /* A packet is ready, read it */ if (listen_mode == LISTEN_KERNEL) - len = udhcp_recv_packet(&packet, sockfd); + len = udhcp_recv_kernel_packet(&packet, sockfd); else - len = get_raw_packet(&packet, sockfd); - - if (len == -1) { /* error is severe, reopen socket */ - DEBUG("error on read, %s, reopening socket", strerror(errno)); + len = udhcp_recv_raw_packet(&packet, sockfd); + if (len == -1) { + /* Error is severe, reopen socket */ + bb_info_msg("Read error: %s, reopening socket", strerror(errno)); + sleep(discover_timeout); /* 3 seconds by default */ change_listen_mode(listen_mode); /* just close and reopen */ } - if (len < 0) continue; - - if (packet.xid != xid) { - DEBUG("Ignoring XID %x (our xid is %x)", - (unsigned)packet.xid, (unsigned)xid); + /* 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; - } + } - /* Ignore packets that aren't for us */ - if (memcmp(packet.chaddr, client_config.arp, 6)) { - DEBUG("Packet does not have our chaddr - ignoring"); - continue; - } + if (packet.xid != xid) { + log1("xid %x (our is %x), ignoring packet", + (unsigned)packet.xid, (unsigned)xid); + continue; + } - message = get_option(&packet, DHCP_MESSAGE_TYPE); - if (message == NULL) { - bb_error_msg("cannot get message type from packet - ignoring"); - 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) { +/* 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) { + uint32_t lease_seconds; + struct in_addr temp_addr; - switch (state) { - case INIT_SELECTING: - /* Must be a DHCPOFFER to one of our xid's */ - if (*message == DHCPOFFER) { - /* TODO: why we don't just fetch server's IP from IP header? */ - temp = get_option(&packet, DHCP_SERVER_ID); - if (!temp) { - bb_error_msg("no server ID in message"); - continue; - /* still selecting - this server looks bad */ - } - /* can be misaligned, thus memcpy */ - memcpy(&server_addr, temp, 4); - xid = packet.xid; - requested_ip = packet.yiaddr; - - /* enter requesting state */ - state = REQUESTING; - timeout = 0; - packet_num = 0; + 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 >= 0x10000000) + lease_seconds = 0x0fffffff; } - continue; - case RENEW_REQUESTED: - case REQUESTING: - case RENEWING: - case REBINDING: - if (*message == DHCPACK) { - temp = 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 { - /* can be misaligned, thus memcpy */ - memcpy(&lease_seconds, temp, 4); - lease_seconds = ntohl(lease_seconds); - } #if ENABLE_FEATURE_UDHCPC_ARPING - if (opt & OPT_a) { - if (!arpping(packet.yiaddr, - (uint32_t) 0, - client_config.arp, - client_config.interface) - ) { - bb_info_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; - requested_ip = 0; - timeout = tryagain_timeout; - packet_num = 0; - continue; /* back to main loop */ - } + 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) + ) { + bb_info_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 */ - t1 = lease_seconds / 2; - - /* little fixed point for n * .875 */ - t2 = (lease_seconds * 7) >> 3; - temp_addr.s_addr = packet.yiaddr; - bb_info_msg("Lease of %s obtained, lease time %u", - inet_ntoa(temp_addr), (unsigned)lease_seconds); - timestamp_got_lease = monotonic_sec(); - timeout = t1; - requested_ip = packet.yiaddr; - udhcp_run_script(&packet, - ((state == RENEWING || state == REBINDING) ? "renew" : "bound")); - - state = BOUND; - change_listen_mode(LISTEN_NONE); - if (client_config.quit_after_lease) { - if (client_config.release_on_quit) - perform_release(); - goto ret0; - } - if (!client_config.foreground) - client_background(); + /* enter bound state */ + timeout = lease_seconds / 2; + temp_addr.s_addr = packet.yiaddr; + bb_info_msg("Lease of %s obtained, lease time %u", + inet_ntoa(temp_addr), (unsigned)lease_seconds); + requested_ip = packet.yiaddr; + udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew"); - continue; /* back to main loop */ + state = BOUND; + change_listen_mode(LISTEN_NONE); + if (opt & OPT_q) { /* quit after lease */ + goto ret0; } - if (*message == DHCPNAK) { - /* return to init state */ - bb_info_msg("Received 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; - requested_ip = 0; - timeout = 0; - packet_num = 0; + /* 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); } - continue; - /* case BOUND, RELEASED: - ignore all packets */ +#endif + /* make future renew packets use different xid */ + /* xid = random_xid(); ...but why bother? */ + already_waited_sec = 0; + continue; /* back to main loop */ } - continue; /* back to main loop */ - } - - /* select() didn't timeout, something did happen. - * But it wasn't a packet. It's a signal pipe then. */ - { - int signo = udhcp_sp_read(&rfds); - switch (signo) { - case SIGUSR1: - perform_renew(); - /* start things over */ - packet_num = 0; - /* Kill any timeouts because the user wants this to hurry along */ + if (*message == DHCPNAK) { + /* return to init state */ + bb_info_msg("Received 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; - break; - case SIGUSR2: - perform_release(); - break; - case SIGTERM: - bb_info_msg("Received SIGTERM"); - if (client_config.release_on_quit) - perform_release(); - goto ret0; + 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 it's own check */ + /*if (client_config.pidfile) - remove_pidfile has its own check */ remove_pidfile(client_config.pidfile); return retval; }