X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fdhcpc.c;h=8dee916d9892cdb6d2eb249916109a8ccff9478c;hb=cb1dc1d1d1c0132636454ecfdb6cac3eade323e6;hp=5d3291b8cd46328cbc1c85b737ffd0edd4f4bc2b;hpb=5d3aaceb790461dca3f770483bbccd161e78a728;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 5d3291b8c..8dee916d9 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -25,17 +25,11 @@ #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 @@ -52,7 +46,6 @@ static const char udhcpc_longopts[] ALIGN1 = "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" @@ -106,7 +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 @@ -141,6 +136,63 @@ 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_optflag *optflag, const char *opt_name) { @@ -148,27 +200,25 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ 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]; + /* 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) { - unsigned ip_ofs = 0; - switch (type) { + case OPTION_IP: case OPTION_IP_PAIR: dest += sprint_nip(dest, "", option); - *dest++ = '/'; - ip_ofs = 4; - /* fall through */ - case OPTION_IP: - dest += sprint_nip(dest, "", option + ip_ofs); + if (type == OPTION_IP) + break; + dest += sprint_nip(dest, "/", option + 4); break; // case OPTION_BOOLEAN: // dest += sprintf(dest, *option ? "yes" : "no"); @@ -190,10 +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] @@ -238,6 +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=") */ @@ -277,16 +381,21 @@ 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; // 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 <= 0 /* || !(optflag->flags & OPTION_LIST) */) + if (len < optlen /* || !(optflag->flags & OPTION_LIST) */) break; *dest++ = ' '; *dest = '\0'; - } + } /* while */ + return ret; } @@ -320,13 +429,14 @@ static char **fill_envp(struct dhcp_packet *packet) /* +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 mton */ + envc++; /* for $mask */ envc++; /*if (i != DHCP_MESSAGE_TYPE)*/ FOUND_OPTS(i) |= BMASK(i); @@ -341,10 +451,42 @@ static char **fill_envp(struct dhcp_packet *packet) 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 $ip */ *curr = xmalloc(sizeof("ip=255.255.255.255")); sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr); putenv(*curr++); + if (packet->siaddr_nip) { + /* IP address of next server to use in bootstrap */ + *curr = xmalloc(sizeof("siaddr=255.255.255.255")); + sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip); + putenv(*curr++); + } + if (!(overload & FILE_FIELD) && packet->file[0]) { + /* watch out for invalid packets */ + *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); + putenv(*curr++); + } + if (!(overload & SNAME_FIELD) && packet->sname[0]) { + /* watch out for invalid packets */ + *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); + putenv(*curr++); + } + /* Export known DHCP options */ opt_name = dhcp_option_strings; i = 0; while (*opt_name) { @@ -361,29 +503,14 @@ static char **fill_envp(struct dhcp_packet *packet) /* Subnet option: make things like "$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 (!(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++); - } - /* Handle unknown options */ + /* Export unknown options */ for (i = 0; i < 256;) { BITMAP bitmap = FOUND_OPTS(i); if (!bitmap) { @@ -400,11 +527,12 @@ static char **fill_envp(struct dhcp_packet *packet) 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] = '\0'; + *bin2hex(*curr + ofs, (void*) temp, len) = '\0'; putenv(*curr++); } i++; } + return envp; } @@ -414,9 +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 */ @@ -464,7 +589,6 @@ static void init_packet(struct dhcp_packet *packet, char type) static void add_client_options(struct dhcp_packet *packet) { - uint8_t c; int i, end, len; udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE)); @@ -474,13 +598,9 @@ static void add_client_options(struct dhcp_packet *packet) * No bounds checking because it goes towards the head of the packet. */ end = udhcp_end_option(packet->options); len = 0; - for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) { - if (( (dhcp_optflags[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; + 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++; } } @@ -513,6 +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 @@ -541,6 +667,15 @@ 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 */ /* NOINLINE: limit stack usage in caller */ static NOINLINE int send_discover(uint32_t xid, uint32_t requested) @@ -647,17 +782,13 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) 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 */ /* NOINLINE: limit stack usage in caller */ -static NOINLINE int send_decline(uint32_t xid, uint32_t server, uint32_t requested) +static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested) { struct dhcp_packet packet; @@ -666,12 +797,14 @@ static NOINLINE int send_decline(uint32_t xid, uint32_t server, uint32_t request */ 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); @@ -698,7 +831,11 @@ static int send_release(uint32_t server, uint32_t 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 */ @@ -708,13 +845,31 @@ 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))) { @@ -732,7 +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 */ @@ -745,31 +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; } @@ -853,7 +1026,7 @@ 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? sock.sll_family = AF_PACKET; sock.sll_protocol = htons(ETH_P_IP); @@ -865,7 +1038,14 @@ static int udhcp_raw_socket(int ifindex) /* 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"); } log1("Created raw socket"); @@ -916,7 +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; @@ -964,41 +1144,41 @@ static void client_background(void) //usage:# define IF_UDHCP_VERBOSE(...) //usage:#endif //usage:#define udhcpc_trivial_usage -//usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n" -//usage: " [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]") +//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: "\n -p,--pidfile FILE Create pidfile" +//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" -//usage: "\n -T,--timeout N Pause between packets (default 3 seconds)" -//usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)" +//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 -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 -S,--syslog Log to syslog too" -//usage: IF_FEATURE_UDHCP_PORT( -//usage: "\n -P,--client-port N Use port N (default 68)" -//usage: ) //usage: IF_FEATURE_UDHCPC_ARPING( //usage: "\n -a,--arping Use arping to validate offered address" //usage: ) -//usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)" -//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)" //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 -H,-h,--hostname NAME Send NAME as client hostname (default none)" //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( @@ -1007,36 +1187,35 @@ static void client_background(void) //usage: ) //usage: IF_NOT_LONG_OPTS( //usage: "\n -i IFACE Interface to use (default eth0)" -//usage: "\n -p FILE Create pidfile" +//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" -//usage: "\n -T N Pause between packets (default 3 seconds)" -//usage: "\n -A N Wait N seconds (default 20) after failure" +//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 -n Exit if lease is not obtained" -//usage: "\n -q Exit after obtaining lease" -//usage: "\n -R Release IP on exit" //usage: "\n -S Log to syslog too" -//usage: IF_FEATURE_UDHCP_PORT( -//usage: "\n -P N Use port N (default 68)" -//usage: ) //usage: IF_FEATURE_UDHCPC_ARPING( //usage: "\n -a Use arping to validate offered address" //usage: ) -//usage: "\n -O OPT Request option OPT from server (cumulative)" -//usage: "\n -o Don't request any options (unless -O is given)" //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 -H,-h NAME Send NAME as client hostname (default none)" //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')" //usage: "\n -C Don't send MAC as client identifier" //usage: IF_UDHCP_VERBOSE( @@ -1044,8 +1223,8 @@ static void client_background(void) //usage: ) //usage: ) //usage: "\nSignals:" -//usage: "\n USR1 Renew current lease" -//usage: "\n USR2 Release current lease" +//usage: "\n USR1 Renew lease" +//usage: "\n USR2 Release lease" int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; @@ -1062,16 +1241,13 @@ 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; /* Default options */ @@ -1083,11 +1259,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) /* Parse command line */ /* O,x: list; -T,-t,-A take numeric param */ - opt_complementary = "O::x::T+:t+:A+" -#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 - ":vv" -#endif - ; + 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") @@ -1101,12 +1273,13 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) , &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); @@ -1130,8 +1303,6 @@ 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 = bb_strtou(optstr, NULL, 0); @@ -1141,6 +1312,14 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) } client_config.opt_mask[n >> 3] |= 1 << (n & 7); } + if (!(opt & OPT_o)) { + unsigned i, n; + for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) { + if (dhcp_optflags[i].flags & OPTION_REQ) { + client_config.opt_mask[n >> 3] |= 1 << (n & 7); + } + } + } while (list_x) { char *optstr = llist_pop(&list_x); char *colon = strchr(optstr, ':'); @@ -1167,8 +1346,16 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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)) { @@ -1206,6 +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; @@ -1225,8 +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 */ @@ -1253,7 +1442,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) NULL, client_config.client_mac) ) { - return 1; /* iface is gone? */ + goto ret0; /* iface is gone? */ } if (clientid_mac_ptr) memcpy(clientid_mac_ptr, client_config.client_mac, 6); @@ -1263,7 +1452,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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 */ @@ -1292,7 +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; @@ -1367,22 +1556,34 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) 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; } @@ -1435,17 +1636,40 @@ 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, ignoring packet"); - 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; - already is */ requested_ip = packet.yiaddr; @@ -1461,6 +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"); @@ -1469,9 +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) { @@ -1492,7 +1721,7 @@ 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"); @@ -1509,20 +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) */ @@ -1534,6 +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 */ } @@ -1560,6 +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 */