diff options
| -rw-r--r-- | networking/udhcp/Kbuild | 2 | ||||
| -rw-r--r-- | networking/udhcp/clientpacket.c | 272 | ||||
| -rw-r--r-- | networking/udhcp/common.h | 1 | ||||
| -rw-r--r-- | networking/udhcp/dhcpc.c | 245 | ||||
| -rw-r--r-- | networking/udhcp/dhcpc.h | 15 |
5 files changed, 240 insertions, 295 deletions
diff --git a/networking/udhcp/Kbuild b/networking/udhcp/Kbuild index 473077e..693f6c8 100644 --- a/networking/udhcp/Kbuild +++ b/networking/udhcp/Kbuild @@ -10,7 +10,7 @@ lib-y:= lib-$(CONFIG_UDHCPC) += common.o options.o packet.o signalpipe.o socket.o lib-$(CONFIG_UDHCPD) += common.o options.o packet.o signalpipe.o socket.o -lib-$(CONFIG_UDHCPC) += dhcpc.o clientpacket.o script.o +lib-$(CONFIG_UDHCPC) += dhcpc.o script.o lib-$(CONFIG_UDHCPD) += dhcpd.o arpping.o files.o leases.o static_leases.o lib-$(CONFIG_DUMPLEASES) += dumpleases.o lib-$(CONFIG_DHCPRELAY) += dhcprelay.o diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c deleted file mode 100644 index b4a75be..0000000 --- a/networking/udhcp/clientpacket.c +++ /dev/null @@ -1,272 +0,0 @@ -/* vi: set sw=4 ts=4: */ -/* clientpacket.c - * - * Packet generation and dispatching functions for the DHCP client. - * - * Russ Dill <Russ.Dill@asu.edu> July 2001 - * - * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. - */ -#include "common.h" -#include "dhcpd.h" -#include "dhcpc.h" -#include "options.h" - -//#include <features.h> -#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION -#include <netpacket/packet.h> -#include <net/ethernet.h> -#else -#include <asm/types.h> -#include <linux/if_packet.h> -#include <linux/if_ether.h> -#endif - - -/* Create a random xid */ -uint32_t FAST_FUNC random_xid(void) -{ - static smallint initialized; - - if (!initialized) { - srand(monotonic_us()); - initialized = 1; - } - return rand(); -} - - -/* Initialize the packet with the proper defaults */ -static void init_packet(struct dhcp_packet *packet, char type) -{ - udhcp_init_header(packet, type); - memcpy(packet->chaddr, client_config.client_mac, 6); - if (client_config.clientid) - add_option_string(packet->options, client_config.clientid); - if (client_config.hostname) - add_option_string(packet->options, client_config.hostname); - if (client_config.fqdn) - add_option_string(packet->options, client_config.fqdn); - if (type != DHCPDECLINE - && type != DHCPRELEASE - && client_config.vendorclass - ) { - add_option_string(packet->options, client_config.vendorclass); - } -} - - -/* Add a parameter request list for stubborn DHCP servers. Pull the data - * from the struct in options.c. Don't do bounds checking here because it - * goes towards the head of the packet. */ -static void add_param_req_option(struct dhcp_packet *packet) -{ - uint8_t c; - int end = 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; - 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; - } -} - -/* 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); -} - - -/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ -int FAST_FUNC send_discover(uint32_t xid, uint32_t requested) -{ - struct dhcp_packet packet; - - init_packet(&packet, DHCPDISCOVER); - packet.xid = xid; - if (requested) - add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); - /* Explicitly saying that we want RFC-compliant packets helps - * some buggy DHCP servers to NOT send bigger packets */ - add_simple_option(packet.options, DHCP_MAX_SIZE, htons(576)); - add_param_req_option(&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..." - */ -int FAST_FUNC send_select(uint32_t xid, uint32_t server, uint32_t requested) -{ - struct dhcp_packet packet; - struct in_addr addr; - - init_packet(&packet, DHCPREQUEST); - packet.xid = xid; - add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); - add_simple_option(packet.options, DHCP_SERVER_ID, server); - add_param_req_option(&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 */ -int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) -{ - struct dhcp_packet packet; - - init_packet(&packet, DHCPREQUEST); - packet.xid = xid; - packet.ciaddr = ciaddr; - add_param_req_option(&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); -} - - -#if ENABLE_FEATURE_UDHCPC_ARPING -/* Broadcast a DHCP decline message */ -int FAST_FUNC send_decline(uint32_t xid, uint32_t server, uint32_t requested) -{ - struct dhcp_packet packet; - - init_packet(&packet, DHCPDECLINE); - packet.xid = xid; - add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); - add_simple_option(packet.options, DHCP_SERVER_ID, server); - - bb_info_msg("Sending decline..."); - return raw_bcast_from_client_config_ifindex(&packet); -} -#endif - - -/* Unicast a DHCP release message */ -int FAST_FUNC send_release(uint32_t server, uint32_t ciaddr) -{ - struct dhcp_packet packet; - - init_packet(&packet, DHCPRELEASE); - packet.xid = random_xid(); - packet.ciaddr = ciaddr; - - add_simple_option(packet.options, DHCP_SERVER_ID, server); - - bb_info_msg("Sending release..."); - return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); -} - - -/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */ -int FAST_FUNC udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) -{ - int bytes; - struct ip_udp_dhcp_packet packet; - uint16_t check; - - 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 */ - } - - 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 != udhcp_checksum(&packet.ip, sizeof(packet.ip))) { - log1("Bad IP header checksum, ignoring"); - return -2; - } - - /* 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)) { - log1("Packet with bad UDP checksum received, ignoring"); - return -2; - } - - memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp))); - - if (dhcp_pkt->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)); -} diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h index 70a2dc7..d740ca5 100644 --- a/networking/udhcp/common.h +++ b/networking/udhcp/common.h @@ -136,7 +136,6 @@ uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC; void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC; -/*int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd); - in dhcpc.h */ int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC; int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index a03e25c..d51d8b8 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -63,6 +63,245 @@ static smallint state; /* struct client_config_t client_config is in bb_common_bufsiz1 */ +/* Create a random xid */ +static uint32_t random_xid(void) +{ + static smallint initialized; + + if (!initialized) { + srand(monotonic_us()); + initialized = 1; + } + return rand(); +} + +/* Initialize the packet with the proper defaults */ +static void init_packet(struct dhcp_packet *packet, char type) +{ + udhcp_init_header(packet, type); + memcpy(packet->chaddr, client_config.client_mac, 6); + if (client_config.clientid) + add_option_string(packet->options, client_config.clientid); + if (client_config.hostname) + add_option_string(packet->options, client_config.hostname); + if (client_config.fqdn) + add_option_string(packet->options, client_config.fqdn); + if (type != DHCPDECLINE + && type != DHCPRELEASE + && client_config.vendorclass + ) { + add_option_string(packet->options, client_config.vendorclass); + } +} + +/* Add a parameter request list for stubborn DHCP servers. Pull the data + * from the struct in options.c. Don't do bounds checking here because it + * goes towards the head of the packet. */ +static void add_param_req_option(struct dhcp_packet *packet) +{ + uint8_t c; + int end = 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; + 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; + } +} + +/* 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); +} + +/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ +static int send_discover(uint32_t xid, uint32_t requested) +{ + struct dhcp_packet packet; + + init_packet(&packet, DHCPDISCOVER); + packet.xid = xid; + if (requested) + add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); + /* Explicitly saying that we want RFC-compliant packets helps + * some buggy DHCP servers to NOT send bigger packets */ + add_simple_option(packet.options, DHCP_MAX_SIZE, htons(576)); + add_param_req_option(&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..." + */ +static int send_select(uint32_t xid, uint32_t server, uint32_t requested) +{ + struct dhcp_packet packet; + struct in_addr addr; + + init_packet(&packet, DHCPREQUEST); + packet.xid = xid; + add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); + add_simple_option(packet.options, DHCP_SERVER_ID, server); + add_param_req_option(&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 */ +static int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) +{ + struct dhcp_packet packet; + + init_packet(&packet, DHCPREQUEST); + packet.xid = xid; + packet.ciaddr = ciaddr; + add_param_req_option(&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); +} + +#if ENABLE_FEATURE_UDHCPC_ARPING +/* Broadcast a DHCP decline message */ +static int send_decline(uint32_t xid, uint32_t server, uint32_t requested) +{ + struct dhcp_packet packet; + + init_packet(&packet, DHCPDECLINE); + packet.xid = xid; + add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); + add_simple_option(packet.options, 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; + + init_packet(&packet, DHCPRELEASE); + packet.xid = random_xid(); + packet.ciaddr = ciaddr; + + add_simple_option(packet.options, DHCP_SERVER_ID, server); + + bb_info_msg("Sending release..."); + return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); +} + +/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */ +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; + + 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 */ + } + + 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 != udhcp_checksum(&packet.ip, sizeof(packet.ip))) { + log1("Bad IP header checksum, ignoring"); + return -2; + } + + /* 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)) { + log1("Packet with bad UDP checksum received, ignoring"); + return -2; + } + + memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp))); + + if (dhcp_pkt->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)); +} static int udhcp_raw_socket(int ifindex) { @@ -135,7 +374,6 @@ static int udhcp_raw_socket(int ifindex) return fd; } - /* just a little helper */ static void change_listen_mode(int new_mode) { @@ -157,7 +395,6 @@ static void change_listen_mode(int new_mode) /* else LISTEN_NONE: sockfd stays closed */ } - /* perform a renew */ static void perform_renew(void) { @@ -181,7 +418,6 @@ static void perform_renew(void) } } - /* perform a release */ static void perform_release(uint32_t requested_ip, uint32_t server_addr) { @@ -204,7 +440,6 @@ static void perform_release(uint32_t requested_ip, uint32_t server_addr) state = RELEASED; } - #if BB_MMU static void client_background(void) { @@ -215,7 +450,6 @@ static void client_background(void) } #endif - static uint8_t* alloc_dhcp_option(int code, const char *str, int extra) { uint8_t *storage; @@ -227,7 +461,6 @@ static uint8_t* alloc_dhcp_option(int code, const char *str, int extra) return storage; } - int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int udhcpc_main(int argc UNUSED_PARAM, char **argv) { diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h index c9827b6..a886156 100644 --- a/networking/udhcp/dhcpc.h +++ b/networking/udhcp/dhcpc.h @@ -1,5 +1,4 @@ /* vi: set sw=4 ts=4: */ -/* dhcpc.h */ #ifndef UDHCP_DHCPC_H #define UDHCP_DHCPC_H 1 @@ -30,20 +29,6 @@ struct client_config_t { #define CLIENT_PORT 68 #endif - -/*** clientpacket.h ***/ - -uint32_t random_xid(void) FAST_FUNC; -int send_discover(uint32_t xid, uint32_t requested) FAST_FUNC; -int send_select(uint32_t xid, uint32_t server, uint32_t requested) FAST_FUNC; -#if ENABLE_FEATURE_UDHCPC_ARPING -int send_decline(uint32_t xid, uint32_t server, uint32_t requested) FAST_FUNC; -#endif -int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) FAST_FUNC; -int send_release(uint32_t server, uint32_t ciaddr) FAST_FUNC; - -int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) FAST_FUNC; - POP_SAVED_FUNCTION_VISIBILITY #endif |