X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fclientpacket.c;h=29d0d9a1d7a12a2c9618ec504d4bc915404599be;hb=95891fc016c9911406cb826540873f0894bcbe8b;hp=406fe340a9e6df52db6379a684b3b2833dade708;hpb=35ff74676b54b1cae5a6324d2517568393fedbc8;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c index 406fe340a..29d0d9a1d 100644 --- a/networking/udhcp/clientpacket.c +++ b/networking/udhcp/clientpacket.c @@ -48,40 +48,48 @@ static void init_packet(struct dhcpMessage *packet, char type) add_option_string(packet->options, client_config.hostname); if (client_config.fqdn) add_option_string(packet->options, client_config.fqdn); - add_option_string(packet->options, client_config.vendorclass); + if ((type != DHCPDECLINE) && (type != DHCPRELEASE)) + 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_requests(struct dhcpMessage *packet) +static void add_param_req_option(struct dhcpMessage *packet) { + uint8_t c; int end = end_option(packet->options); int i, len = 0; packet->options[end + OPT_CODE] = DHCP_PARAM_REQ; - for (i = 0; dhcp_options[i].code; i++) - if (dhcp_options[i].flags & OPTION_REQ) - packet->options[end + OPT_DATA + len++] = dhcp_options[i].code; + for (i = 0; (c = dhcp_options[i].code) != 0; i++) { + if ((dhcp_options[i].flags & OPTION_REQ) + || (client_config.opt_mask[c >> 3] & (1 << (c & 7))) + ) { + packet->options[end + OPT_DATA + len] = c; + len++; + } + } packet->options[end + OPT_LEN] = len; packet->options[end + OPT_DATA + len] = DHCP_END; - } + #if ENABLE_FEATURE_UDHCPC_ARPING /* Unicast a DHCP decline message */ -int send_decline(uint32_t xid, uint32_t server) +int send_decline(uint32_t xid, uint32_t server, uint32_t requested) { struct dhcpMessage packet; init_packet(&packet, DHCPDECLINE); packet.xid = xid; - add_requests(&packet); + add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); + add_simple_option(packet.options, DHCP_SERVER_ID, server); bb_info_msg("Sending decline..."); - return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, + return udhcp_send_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex); } #endif @@ -99,9 +107,9 @@ int send_discover(uint32_t xid, uint32_t 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_requests(&packet); + add_param_req_option(&packet); bb_info_msg("Sending discover..."); - return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, + return udhcp_send_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex); } @@ -118,10 +126,10 @@ int send_selecting(uint32_t xid, uint32_t server, uint32_t requested) add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); add_simple_option(packet.options, DHCP_SERVER_ID, server); - add_requests(&packet); + add_param_req_option(&packet); addr.s_addr = requested; bb_info_msg("Sending select for %s...", inet_ntoa(addr)); - return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, + return udhcp_send_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex); } @@ -135,12 +143,12 @@ int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) packet.xid = xid; packet.ciaddr = ciaddr; - add_requests(&packet); + add_param_req_option(&packet); bb_info_msg("Sending renew..."); if (server) - return udhcp_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); + return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); - return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, + return udhcp_send_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex); } @@ -154,84 +162,78 @@ int send_release(uint32_t server, uint32_t ciaddr) packet.xid = random_xid(); packet.ciaddr = ciaddr; - add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr); add_simple_option(packet.options, DHCP_SERVER_ID, server); bb_info_msg("Sending release..."); - return udhcp_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); + return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); } -/* return -1 on errors that are fatal for the socket, -2 for those that aren't */ +/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */ int get_raw_packet(struct dhcpMessage *payload, int fd) { int bytes; struct udp_dhcp_packet packet; - uint32_t source, dest; uint16_t check; - memset(&packet, 0, sizeof(struct udp_dhcp_packet)); - bytes = read(fd, &packet, sizeof(struct udp_dhcp_packet)); + memset(&packet, 0, sizeof(packet)); + bytes = safe_read(fd, &packet, sizeof(packet)); if (bytes < 0) { DEBUG("Cannot read on raw listening socket - ignoring"); sleep(1); /* possible down interface, looping condition */ - return -1; + return bytes; /* returns -1 */ } - if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) { - DEBUG("Message too short, ignoring"); + if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) { + DEBUG("Packet is too short, ignoring"); return -2; } if (bytes < ntohs(packet.ip.tot_len)) { - DEBUG("Truncated packet"); + /* packet is bigger than sizeof(packet), we did partial read */ + DEBUG("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 */ + /* 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(struct udp_dhcp_packet) + /* || bytes > (int) sizeof(packet) - can't happen */ || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip)) ) { DEBUG("Unrelated/bogus packet"); return -2; } - /* check IP checksum */ + /* verify IP checksum */ check = packet.ip.check; packet.ip.check = 0; - if (check != udhcp_checksum(&(packet.ip), sizeof(packet.ip))) { - DEBUG("bad IP header checksum, ignoring"); - return -1; + if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) { + DEBUG("Bad IP header checksum, ignoring"); + return -2; } - /* verify the UDP checksum by replacing the header with a pseudo header */ - source = packet.ip.saddr; - dest = packet.ip.daddr; + /* 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; - memset(&packet.ip, 0, sizeof(packet.ip)); - - packet.ip.protocol = IPPROTO_UDP; - packet.ip.saddr = source; - packet.ip.daddr = dest; - packet.ip.tot_len = packet.udp.len; /* cheat on the psuedo-header */ if (check && check != udhcp_checksum(&packet, bytes)) { bb_error_msg("packet with bad UDP checksum received, ignoring"); return -2; } - memcpy(payload, &(packet.data), bytes - (sizeof(packet.ip) + sizeof(packet.udp))); + memcpy(payload, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp))); if (payload->cookie != htonl(DHCP_MAGIC)) { - bb_error_msg("received bogus message (bad magic) - ignoring"); + bb_error_msg("received bogus message (bad magic), ignoring"); return -2; } - DEBUG("oooooh!!! got some!"); + DEBUG("Got valid DHCP packet"); return bytes - (sizeof(packet.ip) + sizeof(packet.udp)); }