From c7dc79e71ddbc1498736a2bbf65a3da179557f83 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Sun, 21 Mar 2010 06:15:28 +0100 Subject: [PATCH] udhcpd: untangle incredibly messy handling of DHCPREQUEST Also fixes attacks possible via DHCPDECLINE / DHCPRELEASE function old new delta udhcpd_main 1846 1949 +103 send_renew 105 142 +37 send_NAK 61 - -61 send_ACK 180 - -180 ------------------------------------------------------------------------------ (add/remove: 0/2 grow/shrink: 2/0 up/down: 140/-241) Total: -101 bytes Signed-off-by: Denys Vlasenko --- networking/udhcp/clientpacket.c | 52 ++++--- networking/udhcp/common.h | 75 ++++++++- networking/udhcp/dhcpc.h | 1 - networking/udhcp/dhcpd.c | 264 +++++++++++++++++--------------- networking/udhcp/files.c | 14 +- networking/udhcp/options.c | 2 +- networking/udhcp/options.h | 30 ++-- networking/udhcp/packet.c | 11 +- networking/udhcp/script.c | 2 +- 9 files changed, 267 insertions(+), 184 deletions(-) diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c index a255d6e84..a0be42885 100644 --- a/networking/udhcp/clientpacket.c +++ b/networking/udhcp/clientpacket.c @@ -109,24 +109,6 @@ static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *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 - - /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ int FAST_FUNC send_discover(uint32_t xid, uint32_t requested) { @@ -136,11 +118,9 @@ int FAST_FUNC send_discover(uint32_t xid, uint32_t requested) 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..."); @@ -159,7 +139,6 @@ int FAST_FUNC send_select(uint32_t xid, uint32_t server, uint32_t requested) 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); @@ -177,17 +156,46 @@ int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) init_packet(&packet, DHCPREQUEST); packet.xid = xid; + /* RFC 2131: + * "3.2 Client-server interaction - reusing a previously + * allocated network address"... + * The client broadcasts a DHCPREQUEST message on its local subnet. + * The message includes the client's network address in the + * REQUESTED_IP option. As the client has not received its + * network address, it MUST NOT fill in the 'ciaddr' field." + * + * FIXME: we seem to not follow this, we do set ciaddr. + */ packet.ciaddr = ciaddr; - + add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr); + if (server) + add_simple_option(packet.options, DHCP_SERVER_ID, server); 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 */ diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h index d7c874e5b..cf3e0cd39 100644 --- a/networking/udhcp/common.h +++ b/networking/udhcp/common.h @@ -21,11 +21,17 @@ extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */ /*** packet.h ***/ -#define DHCP_OPTIONS_BUFSIZE 308 +/* DHCP protocol. See RFC 2131 */ +#define DHCP_MAGIC 0x63825363 + +#define DHCP_OPTIONS_BUFSIZE 308 + +#define BOOTREQUEST 1 +#define BOOTREPLY 2 //TODO: rename ciaddr/yiaddr/chaddr struct dhcp_packet { - uint8_t op; /* 1 = BOOTREQUEST, 2 = BOOTREPLY */ + uint8_t op; /* BOOTREQUEST or BOOTREPLY */ uint8_t htype; /* hardware address type. 1 = 10mb ethernet */ uint8_t hlen; /* hardware address length */ uint8_t hops; /* used by relay agents only */ @@ -61,6 +67,71 @@ struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet { [(sizeof(struct ip_udp_dhcp_packet) != 576 + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS) ? -1 : 1]; }; +// RFC 2131 Table 5: Fields and options used by DHCP clients +// +// Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE, +// DHCPINFORM DHCPRELEASE +// ----- ------------ ----------- ----------- +// 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST +// 'hops' 0 0 0 +// 'xid' selected by client 'xid' from server selected by +// DHCPOFFER message client +// 'secs' 0 or seconds since 0 or seconds since 0 +// DHCP process started DHCP process started +// 'flags' Set 'BROADCAST' Set 'BROADCAST' 0 +// flag if client flag if client +// requires broadcast requires broadcast +// reply reply +// 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE) +// client's network address client's network +// network address (BOUND/RENEW/REBIND) address +// (DHCPINFORM) (DHCPRELEASE) +// 'yiaddr' 0 0 0 +// 'siaddr' 0 0 0 +// 'giaddr' 0 0 0 +// 'chaddr' client's hardware client's hardware client's hardware +// address address address +// 'sname' options, if options, if (unused) +// indicated in indicated in +// 'sname/file' 'sname/file' +// option; otherwise option; otherwise +// unused unused +// 'file' options, if options, if (unused) +// indicated in indicated in +// 'sname/file' 'sname/file' +// option; otherwise option; otherwise +// unused unused +// 'options' options options (unused) +// +// Option DHCPDISCOVER DHCPREQUEST DHCPDECLINE, +// DHCPINFORM DHCPRELEASE +// ------ ------------ ----------- ----------- +// Requested IP address MAY MUST (in MUST +// (DISCOVER) SELECTING or (DHCPDECLINE), +// MUST NOT INIT-REBOOT) MUST NOT +// (INFORM) MUST NOT (in (DHCPRELEASE) +// BOUND or +// RENEWING) +// IP address lease time MAY MAY MUST NOT +// (DISCOVER) +// MUST NOT +// (INFORM) +// Use 'file'/'sname' fields MAY MAY MAY +// Client identifier MAY MAY MAY +// Vendor class identifier MAY MAY MUST NOT +// Server identifier MUST NOT MUST (after MUST +// SELECTING) +// MUST NOT (after +// INIT-REBOOT, +// BOUND, RENEWING +// or REBINDING) +// Parameter request list MAY MAY MUST NOT +// Maximum message size MAY MAY MUST NOT +// Message SHOULD NOT SHOULD NOT SHOULD +// Site-specific MAY MAY MUST NOT +// All others MAY MAY MUST NOT + + uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC; void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC; diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h index dfab2368c..c9827b6e7 100644 --- a/networking/udhcp/dhcpc.h +++ b/networking/udhcp/dhcpc.h @@ -40,7 +40,6 @@ int send_select(uint32_t xid, uint32_t server, uint32_t requested) FAST_FUNC; 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_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; diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c index f594bad66..a529e1b58 100644 --- a/networking/udhcp/dhcpd.c +++ b/networking/udhcp/dhcpd.c @@ -28,18 +28,8 @@ #include "options.h" -/* send a packet to gateway_nip using the kernel ip stack */ -static int send_packet_to_relay(struct dhcp_packet *dhcp_pkt) -{ - log1("Forwarding packet to relay"); - - return udhcp_send_kernel_packet(dhcp_pkt, - server_config.server_nip, SERVER_PORT, - dhcp_pkt->gateway_nip, SERVER_PORT); -} - -/* send a packet to a specific mac address and ip address by creating our own ip packet */ -static int send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadcast) +/* Send a packet to a specific mac address and ip address by creating our own ip packet */ +static void send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadcast) { const uint8_t *chaddr; uint32_t ciaddr; @@ -69,25 +59,36 @@ static int send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadca chaddr = dhcp_pkt->chaddr; } - return udhcp_send_raw_packet(dhcp_pkt, + udhcp_send_raw_packet(dhcp_pkt, /*src*/ server_config.server_nip, SERVER_PORT, /*dst*/ ciaddr, CLIENT_PORT, chaddr, server_config.ifindex); } -/* Send the dhcp packet. - * If force broadcast is set, the packet will be broadcast. - */ -static int send_packet(struct dhcp_packet *dhcp_pkt, int force_broadcast) +/* Send a packet to gateway_nip using the kernel ip stack */ +static void send_packet_to_relay(struct dhcp_packet *dhcp_pkt) +{ + log1("Forwarding packet to relay"); + + udhcp_send_kernel_packet(dhcp_pkt, + server_config.server_nip, SERVER_PORT, + dhcp_pkt->gateway_nip, SERVER_PORT); +} + +static void send_packet(struct dhcp_packet *dhcp_pkt, int force_broadcast) { if (dhcp_pkt->gateway_nip) - return send_packet_to_relay(dhcp_pkt); - return send_packet_to_client(dhcp_pkt, force_broadcast); + send_packet_to_relay(dhcp_pkt); + else + send_packet_to_client(dhcp_pkt, force_broadcast); } static void init_packet(struct dhcp_packet *packet, struct dhcp_packet *oldpacket, char type) { + /* Sets op, htype, hlen, cookie fields + * and adds DHCP_MESSAGE_TYPE option */ udhcp_init_header(packet, type); + packet->xid = oldpacket->xid; memcpy(packet->chaddr, oldpacket->chaddr, sizeof(oldpacket->chaddr)); packet->flags = oldpacket->flags; @@ -132,26 +133,32 @@ static uint32_t select_lease_time(struct dhcp_packet *packet) return lease_time_sec; } -/* send a DHCP OFFER to a DHCP DISCOVER */ -static int send_offer(struct dhcp_packet *oldpacket, uint32_t static_lease_nip, struct dyn_lease *lease) +/* We got a DHCP DISCOVER. Send an OFFER. */ +static void send_offer(struct dhcp_packet *oldpacket, uint32_t static_lease_nip, struct dyn_lease *lease) { struct dhcp_packet packet; - uint32_t lease_time_sec = server_config.max_lease_sec; - const char *p_host_name; + uint32_t lease_time_sec; struct in_addr addr; init_packet(&packet, oldpacket, DHCPOFFER); - /* ADDME: if static, short circuit */ + /* If it is a static lease, use its IP */ + packet.yiaddr = static_lease_nip; + /* Else: */ if (!static_lease_nip) { + /* We have no static lease for client's chaddr */ uint32_t req_nip; uint8_t *req_ip_opt; + const char *p_host_name; - /* The client is in our lease/offered table */ if (lease) { + /* We have a dynamic lease for client's chaddr. + * Reuse its IP (even if lease is expired). + * Note that we ignore requested IP in this case. + */ packet.yiaddr = lease->lease_nip; } - /* Or the client has requested an IP */ + /* Or: if client has requested an IP */ else if ((req_ip_opt = get_option(oldpacket, DHCP_REQUESTED_IP)) != NULL /* (read IP) */ && (move_from_unaligned32(req_nip, req_ip_opt), 1) @@ -165,50 +172,49 @@ static int send_offer(struct dhcp_packet *oldpacket, uint32_t static_lease_nip, ) { packet.yiaddr = req_nip; } - /* Otherwise, find a free IP */ else { + /* Otherwise, find a free IP */ packet.yiaddr = find_free_or_expired_nip(oldpacket->chaddr); } if (!packet.yiaddr) { - bb_error_msg("no IP addresses to give - OFFER abandoned"); - return -1; + bb_error_msg("no free IP addresses. OFFER abandoned"); + return; } + /* Reserve the IP for a short time hoping to get DHCPREQUEST soon */ p_host_name = (const char*) get_option(oldpacket, DHCP_HOST_NAME); - if (add_lease(packet.chaddr, packet.yiaddr, + lease = add_lease(packet.chaddr, packet.yiaddr, server_config.offer_time, p_host_name, p_host_name ? (unsigned char)p_host_name[OPT_LEN - OPT_DATA] : 0 - ) == 0 - ) { - bb_error_msg("lease pool is full - OFFER abandoned"); - return -1; + ); + if (!lease) { + bb_error_msg("no free IP addresses. OFFER abandoned"); + return; } - lease_time_sec = select_lease_time(oldpacket); - } else { - /* It is a static lease... use it */ - packet.yiaddr = static_lease_nip; } + lease_time_sec = select_lease_time(oldpacket); add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_sec)); add_server_options(&packet); addr.s_addr = packet.yiaddr; bb_info_msg("Sending OFFER of %s", inet_ntoa(addr)); - return send_packet(&packet, /*force_bcast:*/ 0); + /* send_packet emits error message itself if it detects failure */ + send_packet(&packet, /*force_bcast:*/ 0); } -static int send_NAK(struct dhcp_packet *oldpacket) +static void send_NAK(struct dhcp_packet *oldpacket) { struct dhcp_packet packet; init_packet(&packet, oldpacket, DHCPNAK); log1("Sending NAK"); - return send_packet(&packet, /*force_bcast:*/ 1); + send_packet(&packet, /*force_bcast:*/ 1); } -static int send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr) +static void send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr) { struct dhcp_packet packet; uint32_t lease_time_sec; @@ -219,15 +225,13 @@ static int send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr) packet.yiaddr = yiaddr; lease_time_sec = select_lease_time(oldpacket); - add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_sec)); + add_server_options(&packet); - addr.s_addr = packet.yiaddr; + addr.s_addr = yiaddr; bb_info_msg("Sending ACK to %s", inet_ntoa(addr)); - - if (send_packet(&packet, /*force_bcast:*/ 0) < 0) - return -1; + send_packet(&packet, /*force_bcast:*/ 0); p_host_name = (const char*) get_option(oldpacket, DHCP_HOST_NAME); add_lease(packet.chaddr, packet.yiaddr, @@ -239,18 +243,21 @@ static int send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr) /* rewrite the file with leases at every new acceptance */ write_leases(); } - - return 0; } -static int send_inform(struct dhcp_packet *oldpacket) +static void send_inform(struct dhcp_packet *oldpacket) { struct dhcp_packet packet; + /* "The server responds to a DHCPINFORM message by sending a DHCPACK + * message directly to the address given in the 'ciaddr' field + * of the DHCPINFORM message. The server MUST NOT send a lease + * expiration time to the client and SHOULD NOT fill in 'yiaddr'." + */ init_packet(&packet, oldpacket, DHCPACK); add_server_options(&packet); - return send_packet(&packet, /*force_bcast:*/ 0); + send_packet(&packet, /*force_bcast:*/ 0); } @@ -352,6 +359,9 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv) while (1) { /* loop until universe collapses */ int bytes; struct timeval tv; + uint8_t *server_id_opt; + uint8_t *requested_opt; + uint32_t requested_nip = requested_nip; /* for compiler */ if (server_socket < 0) { server_socket = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, @@ -404,124 +414,126 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv) } continue; } - if (packet.hlen != 6) { bb_error_msg("MAC length != 6, ignoring packet"); continue; } - + if (packet.op != BOOTREQUEST) { + bb_error_msg("not a REQUEST, ignoring packet"); + continue; + } state = get_option(&packet, DHCP_MESSAGE_TYPE); - if (state == NULL) { - bb_error_msg("no message type option, ignoring packet"); + if (state == NULL || state[0] < DHCP_MINTYPE || state[0] > DHCP_MAXTYPE) { + bb_error_msg("no or bad message type option, ignoring packet"); continue; } - /* Look for a static lease */ + /* Look for a static/dynamic lease */ static_lease_nip = get_static_nip_by_mac(server_config.static_leases, &packet.chaddr); if (static_lease_nip) { bb_info_msg("Found static lease: %x", static_lease_nip); - memcpy(&fake_lease.lease_mac, &packet.chaddr, 6); fake_lease.lease_nip = static_lease_nip; fake_lease.expires = 0; - lease = &fake_lease; } else { lease = find_lease_by_mac(packet.chaddr); } + /* Get REQUESTED_IP and SERVER_ID if present */ + server_id_opt = get_option(&packet, DHCP_SERVER_ID); + if (server_id_opt) { + uint32_t server_id_net; + move_from_unaligned32(server_id_net, server_id_opt); + if (server_id_net != server_config.server_nip) { + /* client talks to somebody else */ + log1("server ID doesn't match, ignoring"); + continue; + } + } + requested_opt = get_option(&packet, DHCP_REQUESTED_IP); + if (requested_opt) { + move_from_unaligned32(requested_nip, requested_opt); + } + switch (state[0]) { + case DHCPDISCOVER: log1("Received DISCOVER"); - if (send_offer(&packet, static_lease_nip, lease) < 0) { - bb_error_msg("send OFFER failed"); - } + send_offer(&packet, static_lease_nip, lease); break; - case DHCPREQUEST: { - uint8_t *server_id_opt, *requested_opt; - uint32_t server_id_net = server_id_net; /* for compiler */ - uint32_t requested_nip = requested_nip; /* for compiler */ + case DHCPREQUEST: log1("Received REQUEST"); - requested_opt = get_option(&packet, DHCP_REQUESTED_IP); - server_id_opt = get_option(&packet, DHCP_SERVER_ID); - if (requested_opt) - move_from_unaligned32(requested_nip, requested_opt); - if (server_id_opt) - move_from_unaligned32(server_id_net, server_id_opt); - - if (lease) { - if (server_id_opt) { - /* SELECTING State */ - if (server_id_net == server_config.server_nip - && requested_opt - && requested_nip == lease->lease_nip - ) { - send_ACK(&packet, lease->lease_nip); - } - } else if (requested_opt) { - /* INIT-REBOOT State */ - if (lease->lease_nip == requested_nip) - send_ACK(&packet, lease->lease_nip); - else - send_NAK(&packet); - } else if (lease->lease_nip == packet.ciaddr) { - /* RENEWING or REBINDING State */ - send_ACK(&packet, lease->lease_nip); - } else { /* don't know what to do!!!! */ - send_NAK(&packet); - } - - /* what to do if we have no record of the client */ - } else if (server_id_opt) { - /* SELECTING State */ - - } else if (requested_opt) { - /* INIT-REBOOT State */ - lease = find_lease_by_nip(requested_nip); - if (lease) { - if (is_expired_lease(lease)) { - /* probably best if we drop this lease */ - memset(lease->lease_mac, 0, sizeof(lease->lease_mac)); - } else { - /* make some contention for this address */ - send_NAK(&packet); - } - } else { - uint32_t r = ntohl(requested_nip); - if (r < server_config.start_ip - || r > server_config.end_ip - ) { - send_NAK(&packet); - } - /* else remain silent */ - } - - } else { - /* RENEWING or REBINDING State */ + /* RFC 2131: "The REQUESTED_IP option MUST be set + * to the value of 'yiaddr' in the DHCPOFFER message + * from the server." */ + if (!requested_opt) { + log1("no requested IP, ignoring"); + break; + } + if (lease && requested_nip == lease->lease_nip) { + /* client requests IP which matches the lease. + * ACK it, and bump lease expiration time. */ + send_ACK(&packet, lease->lease_nip); + break; + } + if (server_id_opt) { + /* client was talking specifically to us. + * "No, we don't have this IP for you". */ + send_NAK(&packet); } break; - } + case DHCPDECLINE: + /* RFC 2131: + * "If the server receives a DHCPDECLINE message, + * the client has discovered through some other means + * that the suggested network address is already + * in use. The server MUST mark the network address + * as not available and SHOULD notify the local + * sysadmin of a possible configuration problem." + * + * SERVER_ID must be present, + * REQUESTED_IP must be present, + * chaddr must be filled in, + * ciaddr must be 0 (we do not check this) + */ log1("Received DECLINE"); - if (lease) { + if (server_id_opt + && requested_opt + && lease /* chaddr matches this lease */ + && requested_nip == lease->lease_nip + ) { memset(lease->lease_mac, 0, sizeof(lease->lease_mac)); lease->expires = time(NULL) + server_config.decline_time; } break; + case DHCPRELEASE: + /* "Upon receipt of a DHCPRELEASE message, the server + * marks the network address as not allocated." + * + * SERVER_ID must be present, + * REQUESTED_IP must not be present (we do not check this), + * chaddr must be filled in, + * ciaddr must be filled in + */ log1("Received RELEASE"); - if (lease) + if (server_id_opt + && lease /* chaddr matches this lease */ + && packet.ciaddr == lease->lease_nip + ) { lease->expires = time(NULL); + } break; + case DHCPINFORM: log1("Received INFORM"); send_inform(&packet); break; - default: - bb_info_msg("Unsupported DHCP message (%02x) - ignoring", state[0]); } } ret0: diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c index 40cfe9fd2..62f4a388f 100644 --- a/networking/udhcp/files.c +++ b/networking/udhcp/files.c @@ -99,7 +99,7 @@ static void attach_option(struct option_set **opt_list, log2("Attaching option %02x to list", option->code); #if ENABLE_FEATURE_UDHCP_RFC3397 - if ((option->flags & TYPE_MASK) == OPTION_STR1035) + if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035) /* reuse buffer and length for RFC1035-formatted string */ buffer = (char *)dname_enc(NULL, 0, buffer, &length); #endif @@ -118,7 +118,7 @@ static void attach_option(struct option_set **opt_list, new->next = *curr; *curr = new; #if ENABLE_FEATURE_UDHCP_RFC3397 - if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL) + if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035 && buffer != NULL) free(buffer); #endif return; @@ -128,7 +128,7 @@ static void attach_option(struct option_set **opt_list, log1("Attaching option %02x to existing member of list", option->code); if (option->flags & OPTION_LIST) { #if ENABLE_FEATURE_UDHCP_RFC3397 - if ((option->flags & TYPE_MASK) == OPTION_STR1035) + if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035) /* reuse buffer and length for RFC1035-formatted string */ buffer = (char *)dname_enc(existing->data + 2, existing->data[OPT_LEN], buffer, &length); @@ -136,7 +136,7 @@ static void attach_option(struct option_set **opt_list, if (existing->data[OPT_LEN] + length <= 255) { existing->data = xrealloc(existing->data, existing->data[OPT_LEN] + length + 3); - if ((option->flags & TYPE_MASK) == OPTION_STRING) { + if ((option->flags & OPTION_TYPE_MASK) == OPTION_STRING) { /* ' ' can bring us to 256 - bad */ if (existing->data[OPT_LEN] + length >= 255) return; @@ -148,7 +148,7 @@ static void attach_option(struct option_set **opt_list, existing->data[OPT_LEN] += length; } /* else, ignore the data, we could put this in a second option in the future */ #if ENABLE_FEATURE_UDHCP_RFC3397 - if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL) + if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035 && buffer != NULL) free(buffer); #endif } /* else, ignore the new data */ @@ -182,10 +182,10 @@ static int FAST_FUNC read_opt(const char *const_line, void *arg) do { val = strtok(NULL, ", \t"); if (!val) break; - length = dhcp_option_lengths[option->flags & TYPE_MASK]; + length = dhcp_option_lengths[option->flags & OPTION_TYPE_MASK]; retval = 0; opt = buffer; /* new meaning for variable opt */ - switch (option->flags & TYPE_MASK) { + switch (option->flags & OPTION_TYPE_MASK) { case OPTION_IP: retval = read_nip(val, buffer); break; diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c index 5bef985bc..29a264047 100644 --- a/networking/udhcp/options.c +++ b/networking/udhcp/options.c @@ -252,7 +252,7 @@ void FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data uint8_t option[6], len; option[OPT_CODE] = code; - len = dhcp_option_lengths[dh->flags & TYPE_MASK]; + len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK]; option[OPT_LEN] = len; if (BB_BIG_ENDIAN) data <<= 8 * (4 - len); diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h index 05090f12e..3ca4dc42d 100644 --- a/networking/udhcp/options.h +++ b/networking/udhcp/options.h @@ -5,7 +5,6 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN -#define TYPE_MASK 0x0F enum { OPTION_IP = 1, @@ -21,19 +20,13 @@ enum { OPTION_U32, OPTION_S32, OPTION_STATIC_ROUTES, -}; - -/* Client requests this option by default */ -#define OPTION_REQ 0x10 -/* There can be a list of 1 or more of these */ -#define OPTION_LIST 0x20 -/*****************************************************************/ -/* Do not modify below here unless you know what you are doing!! */ -/*****************************************************************/ - -/* DHCP protocol. See RFC 2131 */ -#define DHCP_MAGIC 0x63825363 + OPTION_TYPE_MASK = 0x0f, + /* Client requests this option by default */ + OPTION_REQ = 0x10, + /* There can be a list of 1 or more of these */ + OPTION_LIST = 0x20, +}; /* DHCP option codes (partial list). See RFC 2132 and * http://www.iana.org/assignments/bootp-dhcp-parameters/ @@ -81,7 +74,6 @@ enum { //#define DHCP_WPAD 0xfc /* MSIE's Web Proxy Autodiscovery Protocol */ #define DHCP_END 0xff - /* Offsets in option byte sequence */ #define OPT_CODE 0 #define OPT_LEN 1 @@ -91,12 +83,7 @@ enum { #define FILE_FIELD 1 #define SNAME_FIELD 2 -#define BOOTREQUEST 1 -#define BOOTREPLY 2 - -#define ETH_10MB 1 -#define ETH_10MB_LEN 6 - +/* DHCP_MESSAGE_TYPE values */ #define DHCPDISCOVER 1 /* client -> server */ #define DHCPOFFER 2 /* client <- server */ #define DHCPREQUEST 3 /* client -> server */ @@ -105,6 +92,9 @@ enum { #define DHCPNAK 6 /* client <- server */ #define DHCPRELEASE 7 /* client -> server */ #define DHCPINFORM 8 /* client -> server */ +#define DHCP_MINTYPE DHCPDISCOVER +#define DHCP_MAXTYPE DHCPINFORM + struct dhcp_option { uint8_t flags; diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c index 90410cbc0..84d83098c 100644 --- a/networking/udhcp/packet.c +++ b/networking/udhcp/packet.c @@ -21,7 +21,7 @@ void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) { - memset(packet, 0, sizeof(struct dhcp_packet)); + memset(packet, 0, sizeof(*packet)); packet->op = BOOTREQUEST; /* if client to a server */ switch (type) { case DHCPOFFER: @@ -29,10 +29,11 @@ void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) case DHCPNAK: packet->op = BOOTREPLY; /* if server to client */ } - packet->htype = ETH_10MB; - packet->hlen = ETH_10MB_LEN; + packet->htype = 1; /* ethernet */ + packet->hlen = 6; packet->cookie = htonl(DHCP_MAGIC); - packet->options[0] = DHCP_END; + if (DHCP_END != 0) + packet->options[0] = DHCP_END; add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type); } @@ -228,6 +229,7 @@ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, msg = "sendto"; ret_close: close(fd); + /* FIXME: and if result >= 0 but != IP_UPD_DHCP_SIZE? */ if (result < 0) { ret_msg: bb_perror_msg(msg, "PACKET"); @@ -280,6 +282,7 @@ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, msg = "write"; ret_close: close(fd); + /* FIXME: and if result >= 0 but != DHCP_SIZE? */ if (result < 0) { ret_msg: bb_perror_msg(msg, "UDP"); diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c index b4413fa16..400fd2b9b 100644 --- a/networking/udhcp/script.c +++ b/networking/udhcp/script.c @@ -64,7 +64,7 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ /* option points to OPT_DATA, need to go back and get OPT_LEN */ len = option[OPT_LEN - OPT_DATA]; - type = type_p->flags & TYPE_MASK; + type = type_p->flags & OPTION_TYPE_MASK; optlen = dhcp_option_lengths[type]; upper_length = len_of_option_as_string[type] * (len / optlen); -- 2.25.1