diff options
Diffstat (limited to 'src/libsystemd-network/sd-dhcp-server.c')
| -rw-r--r-- | src/libsystemd-network/sd-dhcp-server.c | 1174 |
1 files changed, 0 insertions, 1174 deletions
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c deleted file mode 100644 index f16314a37f..0000000000 --- a/src/libsystemd-network/sd-dhcp-server.c +++ /dev/null @@ -1,1174 +0,0 @@ -/*** - This file is part of systemd. - - Copyright (C) 2013 Intel Corporation. All rights reserved. - Copyright (C) 2014 Tom Gundersen - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <sys/ioctl.h> - -#include "sd-dhcp-server.h" - -#include "alloc-util.h" -#include "dhcp-internal.h" -#include "dhcp-server-internal.h" -#include "fd-util.h" -#include "in-addr-util.h" -#include "siphash24.h" -#include "string-util.h" -#include "unaligned.h" - -#define DHCP_DEFAULT_LEASE_TIME_USEC USEC_PER_HOUR -#define DHCP_MAX_LEASE_TIME_USEC (USEC_PER_HOUR*12) - -/* configures the server's address and subnet, and optionally the pool's size and offset into the subnet - * the whole pool must fit into the subnet, and may not contain the first (any) nor last (broadcast) address - * moreover, the server's own address may be in the pool, and is in that case reserved in order not to - * accidentally hand it out */ -int sd_dhcp_server_configure_pool(sd_dhcp_server *server, struct in_addr *address, unsigned char prefixlen, uint32_t offset, uint32_t size) { - struct in_addr netmask_addr; - be32_t netmask; - uint32_t server_off, broadcast_off, size_max; - - assert_return(server, -EINVAL); - assert_return(address, -EINVAL); - assert_return(address->s_addr != INADDR_ANY, -EINVAL); - assert_return(prefixlen <= 32, -ERANGE); - assert_return(server->address == INADDR_ANY, -EBUSY); - - assert_se(in_addr_prefixlen_to_netmask(&netmask_addr, prefixlen)); - netmask = netmask_addr.s_addr; - - server_off = be32toh(address->s_addr & ~netmask); - broadcast_off = be32toh(~netmask); - - /* the server address cannot be the subnet address */ - assert_return(server_off != 0, -ERANGE); - - /* nor the broadcast address */ - assert_return(server_off != broadcast_off, -ERANGE); - - /* 0 offset means we should set a default, we skip the first (subnet) address - and take the next one */ - if (offset == 0) - offset = 1; - - size_max = (broadcast_off + 1) /* the number of addresses in the subnet */ - - offset /* exclude the addresses before the offset */ - - 1; /* exclude the last (broadcast) address */ - - /* The pool must contain at least one address */ - assert_return(size_max >= 1, -ERANGE); - - if (size != 0) - assert_return(size <= size_max, -ERANGE); - else - size = size_max; - - server->bound_leases = new0(DHCPLease*, size); - if (!server->bound_leases) - return -ENOMEM; - - server->pool_offset = offset; - server->pool_size = size; - - server->address = address->s_addr; - server->netmask = netmask; - server->subnet = address->s_addr & netmask; - - if (server_off >= offset && server_off - offset < size) - server->bound_leases[server_off - offset] = &server->invalid_lease; - - return 0; -} - -int sd_dhcp_server_is_running(sd_dhcp_server *server) { - assert_return(server, false); - - return !!server->receive_message; -} - -sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) { - - if (!server) - return NULL; - - assert(server->n_ref >= 1); - server->n_ref++; - - return server; -} - -void client_id_hash_func(const void *p, struct siphash *state) { - const DHCPClientId *id = p; - - assert(id); - assert(id->length); - assert(id->data); - - siphash24_compress(&id->length, sizeof(id->length), state); - siphash24_compress(id->data, id->length, state); -} - -int client_id_compare_func(const void *_a, const void *_b) { - const DHCPClientId *a, *b; - - a = _a; - b = _b; - - assert(!a->length || a->data); - assert(!b->length || b->data); - - if (a->length != b->length) - return a->length < b->length ? -1 : 1; - - return memcmp(a->data, b->data, a->length); -} - -static const struct hash_ops client_id_hash_ops = { - .hash = client_id_hash_func, - .compare = client_id_compare_func -}; - -static void dhcp_lease_free(DHCPLease *lease) { - if (!lease) - return; - - free(lease->client_id.data); - free(lease); -} - -sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) { - DHCPLease *lease; - - if (!server) - return NULL; - - assert(server->n_ref >= 1); - server->n_ref--; - - if (server->n_ref > 0) - return NULL; - - log_dhcp_server(server, "UNREF"); - - sd_dhcp_server_stop(server); - - sd_event_unref(server->event); - - free(server->timezone); - free(server->dns); - free(server->ntp); - - while ((lease = hashmap_steal_first(server->leases_by_client_id))) - dhcp_lease_free(lease); - hashmap_free(server->leases_by_client_id); - - free(server->bound_leases); - return mfree(server); -} - -int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) { - _cleanup_(sd_dhcp_server_unrefp) sd_dhcp_server *server = NULL; - - assert_return(ret, -EINVAL); - assert_return(ifindex > 0, -EINVAL); - - server = new0(sd_dhcp_server, 1); - if (!server) - return -ENOMEM; - - server->n_ref = 1; - server->fd_raw = -1; - server->fd = -1; - server->address = htobe32(INADDR_ANY); - server->netmask = htobe32(INADDR_ANY); - server->ifindex = ifindex; - server->leases_by_client_id = hashmap_new(&client_id_hash_ops); - server->default_lease_time = DIV_ROUND_UP(DHCP_DEFAULT_LEASE_TIME_USEC, USEC_PER_SEC); - server->max_lease_time = DIV_ROUND_UP(DHCP_MAX_LEASE_TIME_USEC, USEC_PER_SEC); - - *ret = server; - server = NULL; - - return 0; -} - -int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int64_t priority) { - int r; - - assert_return(server, -EINVAL); - assert_return(!server->event, -EBUSY); - - if (event) - server->event = sd_event_ref(event); - else { - r = sd_event_default(&server->event); - if (r < 0) - return r; - } - - server->event_priority = priority; - - return 0; -} - -int sd_dhcp_server_detach_event(sd_dhcp_server *server) { - assert_return(server, -EINVAL); - - server->event = sd_event_unref(server->event); - - return 0; -} - -sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) { - assert_return(server, NULL); - - return server->event; -} - -int sd_dhcp_server_stop(sd_dhcp_server *server) { - assert_return(server, -EINVAL); - - server->receive_message = - sd_event_source_unref(server->receive_message); - - server->fd_raw = safe_close(server->fd_raw); - server->fd = safe_close(server->fd); - - log_dhcp_server(server, "STOPPED"); - - return 0; -} - -static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, - DHCPPacket *packet, size_t len) { - union sockaddr_union link = { - .ll.sll_family = AF_PACKET, - .ll.sll_protocol = htobe16(ETH_P_IP), - .ll.sll_ifindex = server->ifindex, - .ll.sll_halen = ETH_ALEN, - }; - - assert(server); - assert(server->ifindex > 0); - assert(server->address); - assert(packet); - assert(len > sizeof(DHCPPacket)); - - memcpy(&link.ll.sll_addr, &packet->dhcp.chaddr, ETH_ALEN); - - dhcp_packet_append_ip_headers(packet, server->address, DHCP_PORT_SERVER, - packet->dhcp.yiaddr, - DHCP_PORT_CLIENT, len); - - return dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len); -} - -static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, - uint16_t destination_port, - DHCPMessage *message, size_t len) { - union sockaddr_union dest = { - .in.sin_family = AF_INET, - .in.sin_port = htobe16(destination_port), - .in.sin_addr.s_addr = destination, - }; - struct iovec iov = { - .iov_base = message, - .iov_len = len, - }; - uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))] = {}; - struct msghdr msg = { - .msg_name = &dest, - .msg_namelen = sizeof(dest.in), - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = cmsgbuf, - .msg_controllen = sizeof(cmsgbuf), - }; - struct cmsghdr *cmsg; - struct in_pktinfo *pktinfo; - int r; - - assert(server); - assert(server->fd > 0); - assert(message); - assert(len > sizeof(DHCPMessage)); - - cmsg = CMSG_FIRSTHDR(&msg); - assert(cmsg); - - cmsg->cmsg_level = IPPROTO_IP; - cmsg->cmsg_type = IP_PKTINFO; - cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); - - /* we attach source interface and address info to the message - rather than binding the socket. This will be mostly useful - when we gain support for arbitrary number of server addresses - */ - pktinfo = (struct in_pktinfo*) CMSG_DATA(cmsg); - assert(pktinfo); - - pktinfo->ipi_ifindex = server->ifindex; - pktinfo->ipi_spec_dst.s_addr = server->address; - - r = sendmsg(server->fd, &msg, 0); - if (r < 0) - return -errno; - - return 0; -} - -static bool requested_broadcast(DHCPRequest *req) { - assert(req); - - return req->message->flags & htobe16(0x8000); -} - -int dhcp_server_send_packet(sd_dhcp_server *server, - DHCPRequest *req, DHCPPacket *packet, - int type, size_t optoffset) { - be32_t destination = INADDR_ANY; - uint16_t destination_port = DHCP_PORT_CLIENT; - int r; - - assert(server); - assert(req); - assert(req->max_optlen); - assert(optoffset <= req->max_optlen); - assert(packet); - - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, - SD_DHCP_OPTION_SERVER_IDENTIFIER, - 4, &server->address); - if (r < 0) - return r; - - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, - SD_DHCP_OPTION_END, 0, NULL); - if (r < 0) - return r; - - /* RFC 2131 Section 4.1 - - If the ’giaddr’ field in a DHCP message from a client is non-zero, - the server sends any return messages to the ’DHCP server’ port on the - BOOTP relay agent whose address appears in ’giaddr’. If the ’giaddr’ - field is zero and the ’ciaddr’ field is nonzero, then the server - unicasts DHCPOFFER and DHCPACK messages to the address in ’ciaddr’. - If ’giaddr’ is zero and ’ciaddr’ is zero, and the broadcast bit is - set, then the server broadcasts DHCPOFFER and DHCPACK messages to - 0xffffffff. If the broadcast bit is not set and ’giaddr’ is zero and - ’ciaddr’ is zero, then the server unicasts DHCPOFFER and DHCPACK - messages to the client’s hardware address and ’yiaddr’ address. In - all cases, when ’giaddr’ is zero, the server broadcasts any DHCPNAK - messages to 0xffffffff. - - Section 4.3.2 - - If ’giaddr’ is set in the DHCPREQUEST message, the client is on a - different subnet. The server MUST set the broadcast bit in the - DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the - client, because the client may not have a correct network address - or subnet mask, and the client may not be answering ARP requests. - */ - if (req->message->giaddr) { - destination = req->message->giaddr; - destination_port = DHCP_PORT_SERVER; - if (type == DHCP_NAK) - packet->dhcp.flags = htobe16(0x8000); - } else if (req->message->ciaddr && type != DHCP_NAK) - destination = req->message->ciaddr; - - if (destination != INADDR_ANY) - return dhcp_server_send_udp(server, destination, - destination_port, &packet->dhcp, - sizeof(DHCPMessage) + optoffset); - else if (requested_broadcast(req) || type == DHCP_NAK) - return dhcp_server_send_udp(server, INADDR_BROADCAST, - destination_port, &packet->dhcp, - sizeof(DHCPMessage) + optoffset); - else - /* we cannot send UDP packet to specific MAC address when the - address is not yet configured, so must fall back to raw - packets */ - return dhcp_server_send_unicast_raw(server, packet, - sizeof(DHCPPacket) + optoffset); -} - -static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret, - uint8_t type, size_t *_optoffset, - DHCPRequest *req) { - _cleanup_free_ DHCPPacket *packet = NULL; - size_t optoffset = 0; - int r; - - assert(server); - assert(ret); - assert(_optoffset); - assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK)); - - packet = malloc0(sizeof(DHCPPacket) + req->max_optlen); - if (!packet) - return -ENOMEM; - - r = dhcp_message_init(&packet->dhcp, BOOTREPLY, - be32toh(req->message->xid), type, ARPHRD_ETHER, - req->max_optlen, &optoffset); - if (r < 0) - return r; - - packet->dhcp.flags = req->message->flags; - packet->dhcp.giaddr = req->message->giaddr; - memcpy(&packet->dhcp.chaddr, &req->message->chaddr, ETH_ALEN); - - *_optoffset = optoffset; - *ret = packet; - packet = NULL; - - return 0; -} - -static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req, - be32_t address) { - _cleanup_free_ DHCPPacket *packet = NULL; - size_t offset; - be32_t lease_time; - int r; - - r = server_message_init(server, &packet, DHCP_OFFER, &offset, req); - if (r < 0) - return r; - - packet->dhcp.yiaddr = address; - - lease_time = htobe32(req->lifetime); - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, - &lease_time); - if (r < 0) - return r; - - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_SUBNET_MASK, 4, &server->netmask); - if (r < 0) - return r; - - if (server->emit_router) { - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_ROUTER, 4, &server->address); - if (r < 0) - return r; - } - - r = dhcp_server_send_packet(server, req, packet, DHCP_OFFER, offset); - if (r < 0) - return r; - - return 0; -} - -static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req, - be32_t address) { - _cleanup_free_ DHCPPacket *packet = NULL; - size_t offset; - be32_t lease_time; - int r; - - r = server_message_init(server, &packet, DHCP_ACK, &offset, req); - if (r < 0) - return r; - - packet->dhcp.yiaddr = address; - - lease_time = htobe32(req->lifetime); - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, - &lease_time); - if (r < 0) - return r; - - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_SUBNET_MASK, 4, &server->netmask); - if (r < 0) - return r; - - if (server->emit_router) { - r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_ROUTER, 4, &server->address); - if (r < 0) - return r; - } - - if (server->n_dns > 0) { - r = dhcp_option_append( - &packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_DOMAIN_NAME_SERVER, - sizeof(struct in_addr) * server->n_dns, server->dns); - if (r < 0) - return r; - } - - if (server->n_ntp > 0) { - r = dhcp_option_append( - &packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_NTP_SERVER, - sizeof(struct in_addr) * server->n_ntp, server->ntp); - if (r < 0) - return r; - } - - if (server->timezone) { - r = dhcp_option_append( - &packet->dhcp, req->max_optlen, &offset, 0, - SD_DHCP_OPTION_NEW_TZDB_TIMEZONE, - strlen(server->timezone), server->timezone); - if (r < 0) - return r; - } - - r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset); - if (r < 0) - return r; - - return 0; -} - -static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) { - _cleanup_free_ DHCPPacket *packet = NULL; - size_t offset; - int r; - - r = server_message_init(server, &packet, DHCP_NAK, &offset, req); - if (r < 0) - return r; - - return dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset); -} - -static int server_send_forcerenew(sd_dhcp_server *server, be32_t address, - be32_t gateway, uint8_t chaddr[]) { - _cleanup_free_ DHCPPacket *packet = NULL; - size_t optoffset = 0; - int r; - - assert(server); - assert(address != INADDR_ANY); - assert(chaddr); - - packet = malloc0(sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE); - if (!packet) - return -ENOMEM; - - r = dhcp_message_init(&packet->dhcp, BOOTREPLY, 0, - DHCP_FORCERENEW, ARPHRD_ETHER, - DHCP_MIN_OPTIONS_SIZE, &optoffset); - if (r < 0) - return r; - - r = dhcp_option_append(&packet->dhcp, DHCP_MIN_OPTIONS_SIZE, - &optoffset, 0, SD_DHCP_OPTION_END, 0, NULL); - if (r < 0) - return r; - - memcpy(&packet->dhcp.chaddr, chaddr, ETH_ALEN); - - r = dhcp_server_send_udp(server, address, DHCP_PORT_CLIENT, - &packet->dhcp, - sizeof(DHCPMessage) + optoffset); - if (r < 0) - return r; - - return 0; -} - -static int parse_request(uint8_t code, uint8_t len, const void *option, void *userdata) { - DHCPRequest *req = userdata; - - assert(req); - - switch(code) { - case SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME: - if (len == 4) - req->lifetime = unaligned_read_be32(option); - - break; - case SD_DHCP_OPTION_REQUESTED_IP_ADDRESS: - if (len == 4) - memcpy(&req->requested_ip, option, sizeof(be32_t)); - - break; - case SD_DHCP_OPTION_SERVER_IDENTIFIER: - if (len == 4) - memcpy(&req->server_id, option, sizeof(be32_t)); - - break; - case SD_DHCP_OPTION_CLIENT_IDENTIFIER: - if (len >= 2) { - uint8_t *data; - - data = memdup(option, len); - if (!data) - return -ENOMEM; - - free(req->client_id.data); - req->client_id.data = data; - req->client_id.length = len; - } - - break; - case SD_DHCP_OPTION_MAXIMUM_MESSAGE_SIZE: - - if (len == 2 && unaligned_read_be16(option) >= sizeof(DHCPPacket)) - req->max_optlen = unaligned_read_be16(option) - sizeof(DHCPPacket); - - break; - } - - return 0; -} - -static void dhcp_request_free(DHCPRequest *req) { - if (!req) - return; - - free(req->client_id.data); - free(req); -} - -DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPRequest*, dhcp_request_free); -#define _cleanup_dhcp_request_free_ _cleanup_(dhcp_request_freep) - -static int ensure_sane_request(sd_dhcp_server *server, DHCPRequest *req, DHCPMessage *message) { - assert(req); - assert(message); - - req->message = message; - - /* set client id based on MAC address if client did not send an explicit - one */ - if (!req->client_id.data) { - void *data; - - data = malloc0(ETH_ALEN + 1); - if (!data) - return -ENOMEM; - - ((uint8_t*) data)[0] = 0x01; - memcpy((uint8_t*) data + 1, &message->chaddr, ETH_ALEN); - - req->client_id.length = ETH_ALEN + 1; - req->client_id.data = data; - } - - if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE) - req->max_optlen = DHCP_MIN_OPTIONS_SIZE; - - if (req->lifetime <= 0) - req->lifetime = MAX(1ULL, server->default_lease_time); - - if (server->max_lease_time > 0 && req->lifetime > server->max_lease_time) - req->lifetime = server->max_lease_time; - - return 0; -} - -static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) { - assert(server); - - if (!server->pool_size) - return -EINVAL; - - if (be32toh(requested_ip) < (be32toh(server->subnet) | server->pool_offset) || - be32toh(requested_ip) >= (be32toh(server->subnet) | (server->pool_offset + server->pool_size))) - return -ERANGE; - - return be32toh(requested_ip & ~server->netmask) - server->pool_offset; -} - -#define HASH_KEY SD_ID128_MAKE(0d,1d,fe,bd,f1,24,bd,b3,47,f1,dd,6e,73,21,93,30) - -int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, - size_t length) { - _cleanup_dhcp_request_free_ DHCPRequest *req = NULL; - _cleanup_free_ char *error_message = NULL; - DHCPLease *existing_lease; - int type, r; - - assert(server); - assert(message); - - if (message->op != BOOTREQUEST || - message->htype != ARPHRD_ETHER || - message->hlen != ETHER_ADDR_LEN) - return 0; - - req = new0(DHCPRequest, 1); - if (!req) - return -ENOMEM; - - type = dhcp_option_parse(message, length, parse_request, req, &error_message); - if (type < 0) - return 0; - - r = ensure_sane_request(server, req, message); - if (r < 0) - /* this only fails on critical errors */ - return r; - - existing_lease = hashmap_get(server->leases_by_client_id, - &req->client_id); - - switch(type) { - - case DHCP_DISCOVER: { - be32_t address = INADDR_ANY; - unsigned i; - - log_dhcp_server(server, "DISCOVER (0x%x)", - be32toh(req->message->xid)); - - if (!server->pool_size) - /* no pool allocated */ - return 0; - - /* for now pick a random free address from the pool */ - if (existing_lease) - address = existing_lease->address; - else { - struct siphash state; - uint64_t hash; - uint32_t next_offer; - - /* even with no persistence of leases, we try to offer the same client - the same IP address. we do this by using the hash of the client id - as the offset into the pool of leases when finding the next free one */ - - siphash24_init(&state, HASH_KEY.bytes); - client_id_hash_func(&req->client_id, &state); - hash = htole64(siphash24_finalize(&state)); - next_offer = hash % server->pool_size; - - for (i = 0; i < server->pool_size; i++) { - if (!server->bound_leases[next_offer]) { - address = server->subnet | htobe32(server->pool_offset + next_offer); - break; - } else - next_offer = (next_offer + 1) % server->pool_size; - } - } - - if (address == INADDR_ANY) - /* no free addresses left */ - return 0; - - r = server_send_offer(server, req, address); - if (r < 0) { - /* this only fails on critical errors */ - log_dhcp_server(server, "could not send offer: %s", - strerror(-r)); - return r; - } else { - log_dhcp_server(server, "OFFER (0x%x)", - be32toh(req->message->xid)); - return DHCP_OFFER; - } - - break; - } - case DHCP_DECLINE: - log_dhcp_server(server, "DECLINE (0x%x): %s", be32toh(req->message->xid), strna(error_message)); - - /* TODO: make sure we don't offer this address again */ - - return 1; - - case DHCP_REQUEST: { - be32_t address; - bool init_reboot = false; - int pool_offset; - - /* see RFC 2131, section 4.3.2 */ - - if (req->server_id) { - log_dhcp_server(server, "REQUEST (selecting) (0x%x)", - be32toh(req->message->xid)); - - /* SELECTING */ - if (req->server_id != server->address) - /* client did not pick us */ - return 0; - - if (req->message->ciaddr) - /* this MUST be zero */ - return 0; - - if (!req->requested_ip) - /* this must be filled in with the yiaddr - from the chosen OFFER */ - return 0; - - address = req->requested_ip; - } else if (req->requested_ip) { - log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)", - be32toh(req->message->xid)); - - /* INIT-REBOOT */ - if (req->message->ciaddr) - /* this MUST be zero */ - return 0; - - /* TODO: check more carefully if IP is correct */ - address = req->requested_ip; - init_reboot = true; - } else { - log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)", - be32toh(req->message->xid)); - - /* REBINDING / RENEWING */ - if (!req->message->ciaddr) - /* this MUST be filled in with clients IP address */ - return 0; - - address = req->message->ciaddr; - } - - pool_offset = get_pool_offset(server, address); - - /* verify that the requested address is from the pool, and either - owned by the current client or free */ - if (pool_offset >= 0 && - server->bound_leases[pool_offset] == existing_lease) { - DHCPLease *lease; - usec_t time_now = 0; - - if (!existing_lease) { - lease = new0(DHCPLease, 1); - lease->address = req->requested_ip; - lease->client_id.data = memdup(req->client_id.data, - req->client_id.length); - if (!lease->client_id.data) { - free(lease); - return -ENOMEM; - } - lease->client_id.length = req->client_id.length; - memcpy(&lease->chaddr, &req->message->chaddr, - ETH_ALEN); - lease->gateway = req->message->giaddr; - } else - lease = existing_lease; - - r = sd_event_now(server->event, - clock_boottime_or_monotonic(), - &time_now); - if (r < 0) { - if (!existing_lease) - dhcp_lease_free(lease); - return r; - } - - lease->expiration = req->lifetime * USEC_PER_SEC + time_now; - - r = server_send_ack(server, req, address); - if (r < 0) { - /* this only fails on critical errors */ - log_dhcp_server(server, "could not send ack: %s", - strerror(-r)); - - if (!existing_lease) - dhcp_lease_free(lease); - - return r; - } else { - log_dhcp_server(server, "ACK (0x%x)", - be32toh(req->message->xid)); - - server->bound_leases[pool_offset] = lease; - hashmap_put(server->leases_by_client_id, - &lease->client_id, lease); - - return DHCP_ACK; - } - } else if (init_reboot) { - r = server_send_nak(server, req); - if (r < 0) { - /* this only fails on critical errors */ - log_dhcp_server(server, "could not send nak: %s", - strerror(-r)); - return r; - } else { - log_dhcp_server(server, "NAK (0x%x)", - be32toh(req->message->xid)); - return DHCP_NAK; - } - } - - break; - } - - case DHCP_RELEASE: { - int pool_offset; - - log_dhcp_server(server, "RELEASE (0x%x)", - be32toh(req->message->xid)); - - if (!existing_lease) - return 0; - - if (existing_lease->address != req->message->ciaddr) - return 0; - - pool_offset = get_pool_offset(server, req->message->ciaddr); - if (pool_offset < 0) - return 0; - - if (server->bound_leases[pool_offset] == existing_lease) { - server->bound_leases[pool_offset] = NULL; - hashmap_remove(server->leases_by_client_id, existing_lease); - dhcp_lease_free(existing_lease); - - return 1; - } else - return 0; - } - } - - return 0; -} - -static int server_receive_message(sd_event_source *s, int fd, - uint32_t revents, void *userdata) { - _cleanup_free_ DHCPMessage *message = NULL; - uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))]; - sd_dhcp_server *server = userdata; - struct iovec iov = {}; - struct msghdr msg = { - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = cmsgbuf, - .msg_controllen = sizeof(cmsgbuf), - }; - struct cmsghdr *cmsg; - ssize_t buflen, len; - - assert(server); - - buflen = next_datagram_size_fd(fd); - if (buflen < 0) - return buflen; - - message = malloc(buflen); - if (!message) - return -ENOMEM; - - iov.iov_base = message; - iov.iov_len = buflen; - - len = recvmsg(fd, &msg, 0); - if (len < 0) { - if (errno == EAGAIN || errno == EINTR) - return 0; - - return -errno; - } else if ((size_t)len < sizeof(DHCPMessage)) - return 0; - - CMSG_FOREACH(cmsg, &msg) { - if (cmsg->cmsg_level == IPPROTO_IP && - cmsg->cmsg_type == IP_PKTINFO && - cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) { - struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg); - - /* TODO figure out if this can be done as a filter on - * the socket, like for IPv6 */ - if (server->ifindex != info->ipi_ifindex) - return 0; - - break; - } - } - - return dhcp_server_handle_message(server, message, (size_t)len); -} - -int sd_dhcp_server_start(sd_dhcp_server *server) { - int r; - - assert_return(server, -EINVAL); - assert_return(server->event, -EINVAL); - assert_return(!server->receive_message, -EBUSY); - assert_return(server->fd_raw == -1, -EBUSY); - assert_return(server->fd == -1, -EBUSY); - assert_return(server->address != htobe32(INADDR_ANY), -EUNATCH); - - r = socket(AF_PACKET, SOCK_DGRAM | SOCK_NONBLOCK, 0); - if (r < 0) { - r = -errno; - sd_dhcp_server_stop(server); - return r; - } - server->fd_raw = r; - - r = dhcp_network_bind_udp_socket(INADDR_ANY, DHCP_PORT_SERVER); - if (r < 0) { - sd_dhcp_server_stop(server); - return r; - } - server->fd = r; - - r = sd_event_add_io(server->event, &server->receive_message, - server->fd, EPOLLIN, - server_receive_message, server); - if (r < 0) { - sd_dhcp_server_stop(server); - return r; - } - - r = sd_event_source_set_priority(server->receive_message, - server->event_priority); - if (r < 0) { - sd_dhcp_server_stop(server); - return r; - } - - log_dhcp_server(server, "STARTED"); - - return 0; -} - -int sd_dhcp_server_forcerenew(sd_dhcp_server *server) { - unsigned i; - int r = 0; - - assert_return(server, -EINVAL); - assert(server->bound_leases); - - for (i = 0; i < server->pool_size; i++) { - DHCPLease *lease = server->bound_leases[i]; - - if (!lease || lease == &server->invalid_lease) - continue; - - r = server_send_forcerenew(server, lease->address, - lease->gateway, - lease->chaddr); - if (r < 0) - return r; - else - log_dhcp_server(server, "FORCERENEW"); - } - - return r; -} - -int sd_dhcp_server_set_timezone(sd_dhcp_server *server, const char *tz) { - int r; - - assert_return(server, -EINVAL); - assert_return(timezone_is_valid(tz), -EINVAL); - - if (streq_ptr(tz, server->timezone)) - return 0; - - r = free_and_strdup(&server->timezone, tz); - if (r < 0) - return r; - - return 1; -} - -int sd_dhcp_server_set_max_lease_time(sd_dhcp_server *server, uint32_t t) { - assert_return(server, -EINVAL); - - if (t == server->max_lease_time) - return 0; - - server->max_lease_time = t; - return 1; -} - -int sd_dhcp_server_set_default_lease_time(sd_dhcp_server *server, uint32_t t) { - assert_return(server, -EINVAL); - - if (t == server->default_lease_time) - return 0; - - server->default_lease_time = t; - return 1; -} - -int sd_dhcp_server_set_dns(sd_dhcp_server *server, const struct in_addr dns[], unsigned n) { - assert_return(server, -EINVAL); - assert_return(dns || n <= 0, -EINVAL); - - if (server->n_dns == n && - memcmp(server->dns, dns, sizeof(struct in_addr) * n) == 0) - return 0; - - if (n <= 0) { - server->dns = mfree(server->dns); - server->n_dns = 0; - } else { - struct in_addr *c; - - c = newdup(struct in_addr, dns, n); - if (!c) - return -ENOMEM; - - free(server->dns); - server->dns = c; - server->n_dns = n; - } - - return 1; -} - -int sd_dhcp_server_set_ntp(sd_dhcp_server *server, const struct in_addr ntp[], unsigned n) { - assert_return(server, -EINVAL); - assert_return(ntp || n <= 0, -EINVAL); - - if (server->n_ntp == n && - memcmp(server->ntp, ntp, sizeof(struct in_addr) * n) == 0) - return 0; - - if (n <= 0) { - server->ntp = mfree(server->ntp); - server->n_ntp = 0; - } else { - struct in_addr *c; - - c = newdup(struct in_addr, ntp, n); - if (!c) - return -ENOMEM; - - free(server->ntp); - server->ntp = c; - server->n_ntp = n; - } - - return 1; -} - -int sd_dhcp_server_set_emit_router(sd_dhcp_server *server, int enabled) { - assert_return(server, -EINVAL); - - if (enabled == server->emit_router) - return 0; - - server->emit_router = enabled; - - return 1; -} |