X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fdhcpc.c;h=8dee916d9892cdb6d2eb249916109a8ccff9478c;hb=cb1dc1d1d1c0132636454ecfdb6cac3eade323e6;hp=53e10d00e9e5200d736d3adf1d09aa2c2b76c1d4;hpb=243ddcbc76d19847d9e8022dc2f6659078f5cc20;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 53e10d00e..8dee916d9 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -25,17 +25,71 @@ #include "dhcpd.h" #include "dhcpc.h" -#include -#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION) -# include -# include -#else -# include -# include -#endif +#include #include +#include + +/* "struct client_config_t client_config" is in bb_common_bufsiz1 */ -/* 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 ***/ @@ -45,7 +99,9 @@ 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 @@ -80,34 +136,89 @@ static int mton(uint32_t mask) 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_option *type_p, const char *opt_name) +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 and get OPT_LEN */ - len = option[OPT_LEN - OPT_DATA]; - type = type_p->flags & OPTION_TYPE_MASK; + /* 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 / (unsigned)optlen); + 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_PAIR: - dest += sprint_nip(dest, "", option); - *dest++ = '/'; - option += 4; - optlen = 4; case OPTION_IP: + case OPTION_IP_PAIR: dest += sprint_nip(dest, "", option); -// TODO: it can be a list only if (type_p->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 (type == OPTION_IP) + break; + dest += sprint_nip(dest, "/", option + 4); break; // case OPTION_BOOLEAN: // dest += sprintf(dest, *option ? "yes" : "no"); @@ -129,10 +240,17 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ 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'; - return ret; /* Short circuit this case */ + 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] @@ -177,6 +295,53 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ 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=") */ @@ -216,91 +381,158 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ 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; - if (len <= 0) +// 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 num_options = 0; + int envc; int i; char **envp, **curr; const char *opt_name; uint8_t *temp; - uint8_t over = 0; - + 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) { - for (i = 0; dhcp_options[i].code; i++) { - if (udhcp_get_option(packet, dhcp_options[i].code)) { - num_options++; - if (dhcp_options[i].code == DHCP_SUBNET) - num_options++; /* for mton */ + /* 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); } } - if (packet->siaddr_nip) - num_options++; - temp = udhcp_get_option(packet, DHCP_OPTION_OVERLOAD); - if (temp) - over = *temp; - if (!(over & FILE_FIELD) && packet->file[0]) - num_options++; - if (!(over & SNAME_FIELD) && packet->sname[0]) - num_options++; } + curr = envp = xzalloc(sizeof(envp[0]) * envc); - curr = envp = xzalloc(sizeof(char *) * (num_options + 3)); *curr = xasprintf("interface=%s", client_config.interface); putenv(*curr++); - if (packet == NULL) + 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 $ip */ *curr = xmalloc(sizeof("ip=255.255.255.255")); sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr); putenv(*curr++); + if (packet->siaddr_nip) { + /* IP address of next server to use in bootstrap */ + *curr = xmalloc(sizeof("siaddr=255.255.255.255")); + sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip); + putenv(*curr++); + } + if (!(overload & FILE_FIELD) && packet->file[0]) { + /* watch out for invalid packets */ + *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); + putenv(*curr++); + } + if (!(overload & SNAME_FIELD) && packet->sname[0]) { + /* watch out for invalid packets */ + *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); + putenv(*curr++); + } + /* Export known DHCP options */ opt_name = dhcp_option_strings; i = 0; while (*opt_name) { - temp = udhcp_get_option(packet, dhcp_options[i].code); - if (!temp) + uint8_t code = dhcp_optflags[i].code; + BITMAP *found_ptr = &FOUND_OPTS(code); + BITMAP found_mask = BMASK(code); + if (!(*found_ptr & found_mask)) goto next; - *curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name); + *found_ptr &= ~found_mask; /* leave only unknown options */ + temp = udhcp_get_option(packet, code); + *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name); putenv(*curr++); - - /* Fill in a subnet bits option for things like /24 */ - if (dhcp_options[i].code == DHCP_SUBNET) { + if (code == DHCP_SUBNET) { + /* Subnet option: make things like "$ip/$mask" possible */ uint32_t subnet; move_from_unaligned32(subnet, temp); - *curr = xasprintf("mask=%d", mton(subnet)); + *curr = xasprintf("mask=%u", mton(subnet)); putenv(*curr++); } next: opt_name += strlen(opt_name) + 1; i++; } - if (packet->siaddr_nip) { - *curr = xmalloc(sizeof("siaddr=255.255.255.255")); - sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip); - putenv(*curr++); - } - if (!(over & 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 (!(over & SNAME_FIELD) && packet->sname[0]) { - /* watch out for invalid packets */ - *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); - putenv(*curr++); + /* 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; } @@ -310,9 +542,6 @@ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) char **envp, **curr; char *argv[3]; - if (client_config.script == NULL) - return; - envp = fill_envp(packet); /* call script */ @@ -324,8 +553,7 @@ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) for (curr = envp; *curr; curr++) { log2(" %s", *curr); - bb_unsetenv(*curr); - free(*curr); + bb_unsetenv_and_free(*curr); } free(envp); } @@ -341,38 +569,38 @@ static ALWAYS_INLINE uint32_t random_xid(void) /* 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); - if (client_config.hostname) - udhcp_add_binary_option(packet, client_config.hostname); - if (client_config.fqdn) - udhcp_add_binary_option(packet, client_config.fqdn); - if (type != DHCPDECLINE - && type != DHCPRELEASE - && client_config.vendorclass - ) { - udhcp_add_binary_option(packet, client_config.vendorclass); - } } 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. */ - uint8_t c; - int end = udhcp_end_option(packet->options); - int i, len = 0; - - for (i = 0; (c = dhcp_options[i].code) != 0; i++) { - if (( (dhcp_options[i].flags & OPTION_REQ) - && !client_config.no_default_options - ) - || (client_config.opt_mask[c >> 3] & (1 << (c & 7))) - ) { - packet->options[end + OPT_DATA + len] = c; + 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++; } } @@ -382,6 +610,17 @@ static void add_client_options(struct dhcp_packet *packet) 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; @@ -394,6 +633,12 @@ static void add_client_options(struct dhcp_packet *packet) // 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 @@ -422,18 +667,35 @@ static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet) 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 */ -static int send_discover(uint32_t xid, uint32_t requested) +/* 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); - /* Explicitly saying that we want RFC-compliant packets helps - * some buggy DHCP servers to NOT send bigger packets */ - udhcp_add_simple_option(&packet, DHCP_MAX_SIZE, htons(576)); + + /* 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..."); @@ -444,15 +706,39 @@ static int send_discover(uint32_t xid, uint32_t requested) /* RFC 2131 3.1 paragraph 3: * "The client _broadcasts_ a DHCPREQUEST message..." */ -static int send_select(uint32_t xid, uint32_t server, uint32_t requested) +/* 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; @@ -461,32 +747,67 @@ static int send_select(uint32_t xid, uint32_t server, uint32_t requested) } /* Unicast or broadcast a DHCP renew message */ -static int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) +/* 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..."); - if (server) - return udhcp_send_kernel_packet(&packet, - ciaddr, CLIENT_PORT, - server, SERVER_PORT); - return raw_bcast_from_client_config_ifindex(&packet); + return bcast_or_ucast(&packet, ciaddr, server); } #if ENABLE_FEATURE_UDHCPC_ARPING /* Broadcast a DHCP decline message */ -static int send_decline(uint32_t xid, uint32_t server, uint32_t requested) +/* 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..."); @@ -499,29 +820,56 @@ 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); - packet.xid = random_xid(); + + /* 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..."); - return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); + /* 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; - memset(&packet, 0, sizeof(packet)); - bytes = safe_read(fd, &packet, sizeof(packet)); - if (bytes < 0) { - log1("Packet read error, ignoring"); - /* NB: possible down interface, etc. Caller should pause. */ - return bytes; /* returns -1 */ + /* 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))) { @@ -539,7 +887,8 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) 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 + 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 */ @@ -552,31 +901,48 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) /* verify IP checksum */ check = packet.ip.check; packet.ip.check = 0; - if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) { + 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 != udhcp_checksum(&packet, bytes)) { + if (check && check != inet_cksum((uint16_t *)&packet, bytes)) { log1("Packet with bad UDP checksum received, ignoring"); return -2; } + skip_udp_sum_check: - memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp))); - - if (dhcp_pkt->cookie != htonl(DHCP_MAGIC)) { + if (packet.data.cookie != htonl(DHCP_MAGIC)) { bb_info_msg("Packet with bad magic, ignoring"); return -2; } - log1("Got valid DHCP packet"); - udhcp_dump_packet(dhcp_pkt); - return bytes - (sizeof(packet.ip) + sizeof(packet.udp)); + + log1("Received a packet"); + udhcp_dump_packet(&packet.data); + + bytes -= sizeof(packet.ip) + sizeof(packet.udp); + memcpy(dhcp_pkt, &packet.data, bytes); + return bytes; } @@ -631,22 +997,25 @@ static int udhcp_raw_socket(int ifindex) * * TODO: make conditional? */ -#define SERVER_AND_CLIENT_PORTS ((67 << 16) + 68) static const struct sock_filter filter_instr[] = { - /* check for udp */ + /* load 9th byte (protocol) */ BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9), - BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 2, 0), /* L5, L1, is UDP? */ - /* ugly check for arp on ethernet-like and IPv4 */ - BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2), /* L1: */ - BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x08000604, 3, 4), /* L3, L4 */ - /* skip IP header */ - BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), /* L5: */ - /* check udp source and destination ports */ - BPF_STMT(BPF_LD|BPF_W|BPF_IND, 0), - BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, SERVER_AND_CLIENT_PORTS, 0, 1), /* L3, L4 */ - /* returns */ - BPF_STMT(BPF_RET|BPF_K, 0x0fffffff ), /* L3: pass */ - BPF_STMT(BPF_RET|BPF_K, 0), /* L4: reject */ + /* 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]), @@ -657,20 +1026,28 @@ static int udhcp_raw_socket(int ifindex) log1("Opening raw socket on ifindex %d", ifindex); //log2? fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP)); - log1("Got raw socket fd %d", fd); //log2? + log1("Got raw socket fd"); //log2? - if (SERVER_PORT == 67 && CLIENT_PORT == 68) { - /* Use only if standard ports are in use */ + 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 %d", fd); // log? + 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"); } - sock.sll_family = AF_PACKET; - sock.sll_protocol = htons(ETH_P_IP); - sock.sll_ifindex = ifindex; - xbind(fd, (struct sockaddr *) &sock, sizeof(sock)); log1("Created raw socket"); return fd; @@ -696,6 +1073,7 @@ static void change_listen_mode(int new_mode) /* else LISTEN_NONE: sockfd stays closed */ } +/* Called only on SIGUSR1 */ static void perform_renew(void) { bb_info_msg("Performing a DHCP renew"); @@ -718,7 +1096,7 @@ static void perform_renew(void) } } -static void perform_release(uint32_t requested_ip, uint32_t server_addr) +static void perform_release(uint32_t server_addr, uint32_t requested_ip) { char buffer[sizeof("255.255.255.255")]; struct in_addr temp_addr; @@ -760,12 +1138,102 @@ static void client_background(void) } #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 UNUSED_PARAM, char **argv) { uint8_t *temp, *message; - const char *str_c, *str_V, *str_h, *str_F, *str_r; + 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; llist_t *list_x = NULL; int tryagain_timeout = 20; @@ -773,78 +1241,16 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) int discover_retries = 3; uint32_t server_addr = server_addr; /* for compiler */ uint32_t requested_ip = 0; - uint32_t xid = 0; - uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */ + uint32_t xid = xid; /* for compiler */ int packet_num; int timeout; /* must be signed */ unsigned already_waited_sec; unsigned opt; int max_fd; int retval; - struct timeval tv; - struct dhcp_packet packet; fd_set rfds; -#if ENABLE_LONG_OPTS - static const char udhcpc_longopts[] ALIGN1 = - "clientid\0" Required_argument "c" - "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" - "version\0" No_argument "v" - "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" - IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a") - IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P") - ; -#endif - enum { - OPT_c = 1 << 0, - OPT_C = 1 << 1, - OPT_V = 1 << 2, - OPT_H = 1 << 3, - OPT_h = 1 << 4, - OPT_F = 1 << 5, - OPT_i = 1 << 6, - OPT_n = 1 << 7, - OPT_p = 1 << 8, - OPT_q = 1 << 9, - OPT_R = 1 << 10, - OPT_r = 1 << 11, - OPT_s = 1 << 12, - OPT_T = 1 << 13, - OPT_t = 1 << 14, - OPT_S = 1 << 15, - OPT_A = 1 << 16, - OPT_O = 1 << 17, - OPT_o = 1 << 18, - OPT_x = 1 << 19, - OPT_f = 1 << 20, -/* The rest has variable bit positions, need to be clever */ - OPTBIT_f = 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,) - }; - - /* Default options. */ + /* Default options */ IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;) IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;) client_config.interface = "eth0"; @@ -852,31 +1258,28 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) str_V = "udhcp "BB_VER; /* Parse command line */ - /* Cc: mutually exclusive; O,x: list; -T,-t,-A take numeric param */ - opt_complementary = "c--C:C--c:O::x::T+:t+:A+" -#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 - ":vv" -#endif - ; + /* 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, "c:CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:f" + 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_c, &str_V, &str_h, &str_h, &str_F + , &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 , &list_x IF_FEATURE_UDHCP_PORT(, &str_P) -#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 - , &dhcp_verbose -#endif - ); - if (opt & (OPT_h|OPT_H)) + 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); @@ -900,23 +1303,30 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) SERVER_PORT = CLIENT_PORT - 1; } #endif - if (opt & OPT_o) - client_config.no_default_options = 1; while (list_O) { char *optstr = llist_pop(&list_O); - unsigned n = udhcp_option_idx(optstr); - n = dhcp_options[n].code; + 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); } + 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) { - unsigned n; char *optstr = llist_pop(&list_x); char *colon = strchr(optstr, ':'); - if (colon) - *colon = '\0'; - n = udhcp_option_idx(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); } @@ -928,16 +1338,24 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) return 1; } - if (opt & OPT_c) { - client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0); - } else if (!(opt & OPT_C)) { - /* not set and not suppressed, set the default client ID */ + 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 */ - memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6); + clientid_mac_ptr = client_config.clientid + OPT_DATA+1; + memcpy(clientid_mac_ptr, client_config.client_mac, 6); } - if (str_V[0] != '\0') + 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)) { @@ -975,6 +1393,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) * "continue" statements in code below jump to the top of the loop. */ for (;;) { + struct timeval tv; + struct dhcp_packet packet; /* silence "uninitialized!" warning */ unsigned timestamp_before_wait = timestamp_before_wait; @@ -994,8 +1414,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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(); - log1("Waiting on select..."); retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); if (retval < 0) { /* EINTR? A signal was caught, don't panic */ @@ -1012,12 +1432,27 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) * 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(); /* broadcast */ @@ -1046,7 +1481,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) packet_num = 0; continue; case REQUESTING: - if (packet_num < discover_retries) { + if (!discover_retries || packet_num < discover_retries) { /* send broadcast select packet */ send_select(xid, server_addr, requested_ip); timeout = discover_timeout; @@ -1063,6 +1498,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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 */ @@ -1102,6 +1538,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) bb_info_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; @@ -1118,22 +1555,35 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) /* 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) + 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(requested_ip, server_addr); + perform_release(server_addr, requested_ip); timeout = INT_MAX; continue; case SIGTERM: bb_info_msg("Received SIGTERM"); - if (opt & OPT_R) /* release on quit */ - perform_release(requested_ip, server_addr); goto ret0; } @@ -1171,7 +1621,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) /* Ignore packets that aren't for us */ if (packet.hlen != 6 - || memcmp(packet.chaddr, client_config.client_mac, 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? @@ -1186,18 +1636,41 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) switch (state) { case INIT_SELECTING: - /* Must be a DHCPOFFER to one of our xid's */ + /* Must be a DHCPOFFER */ if (*message == DHCPOFFER) { - /* TODO: why we don't just fetch server's IP from IP header? */ +/* 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 in message"); - continue; - /* still selecting - this server looks bad */ + 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); } - /* it IS unaligned sometimes, don't "optimize" */ - move_from_unaligned32(server_addr, temp); - xid = packet.xid; + /*xid = packet.xid; - already is */ requested_ip = packet.yiaddr; /* enter requesting state */ @@ -1212,6 +1685,9 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) case RENEW_REQUESTED: case REBINDING: if (*message == DHCPACK) { + uint32_t lease_seconds; + struct in_addr temp_addr; + temp = udhcp_get_option(&packet, DHCP_LEASE_TIME); if (!temp) { bb_error_msg("no lease time with ACK, using 1 hour lease"); @@ -1220,9 +1696,11 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) /* it IS unaligned sometimes, don't "optimize" */ move_from_unaligned32(lease_seconds, temp); lease_seconds = ntohl(lease_seconds); - lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */ - if (lease_seconds < 10) /* and not too small */ - lease_seconds = 10; + /* 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; } #if ENABLE_FEATURE_UDHCPC_ARPING if (opt & OPT_a) { @@ -1243,12 +1721,13 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) ) { bb_info_msg("Offered address is in use " "(got ARP reply), declining"); - send_decline(xid, server_addr, packet.yiaddr); + 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; @@ -1259,20 +1738,15 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) #endif /* enter bound state */ timeout = lease_seconds / 2; - { - struct in_addr temp_addr; - temp_addr.s_addr = packet.yiaddr; - bb_info_msg("Lease of %s obtained, lease time %u", - inet_ntoa(temp_addr), (unsigned)lease_seconds); - } + 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"); state = BOUND; change_listen_mode(LISTEN_NONE); if (opt & OPT_q) { /* quit after lease */ - if (opt & OPT_R) /* release on quit */ - perform_release(requested_ip, server_addr); goto ret0; } /* future renew failures should not exit (JM) */ @@ -1284,6 +1758,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) opt = ((opt & ~OPT_b) | OPT_f); } #endif + /* make future renew packets use different xid */ + /* xid = random_xid(); ...but why bother? */ already_waited_sec = 0; continue; /* back to main loop */ } @@ -1296,6 +1772,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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; @@ -1309,6 +1786,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) } /* 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 */