diff options
Diffstat (limited to 'src/libsystemd-network/sd-dhcp-server.c')
| -rw-r--r-- | src/libsystemd-network/sd-dhcp-server.c | 324 |
1 files changed, 243 insertions, 81 deletions
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c index cc5e032344..d27bb561ca 100644 --- a/src/libsystemd-network/sd-dhcp-server.c +++ b/src/libsystemd-network/sd-dhcp-server.c @@ -22,75 +22,103 @@ #include <sys/ioctl.h> +#include "in-addr-util.h" #include "siphash24.h" #include "sd-dhcp-server.h" #include "dhcp-server-internal.h" #include "dhcp-internal.h" -#define DHCP_DEFAULT_LEASE_TIME 3600 /* one hour */ +#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; -int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, - struct in_addr *address, - size_t size) { assert_return(server, -EINVAL); assert_return(address, -EINVAL); - assert_return(address->s_addr, -EINVAL); - assert_return(size, -EINVAL); - assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY); - assert_return(!server->pool_size, -EBUSY); - assert_return(!server->bound_leases, -EBUSY); + 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_start = address->s_addr; + server->pool_offset = offset; server->pool_size = size; - return 0; -} - -int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address, - unsigned char prefixlen) { - assert_return(server, -EINVAL); - assert_return(address, -EINVAL); - assert_return(address->s_addr, -EINVAL); - assert_return(prefixlen <= 32, -ERANGE); - assert_return(server->address == htobe32(INADDR_ANY), -EBUSY); - assert_return(server->netmask == htobe32(INADDR_ANY), -EBUSY); - server->address = address->s_addr; - server->netmask = htobe32(0xfffffffflu << (32 - prefixlen)); + 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; } bool sd_dhcp_server_is_running(sd_dhcp_server *server) { - assert_return(server, -EINVAL); + assert_return(server, false); return !!server->receive_message; } sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) { - if (server) - assert_se(REFCNT_INC(server->n_ref) >= 2); + + if (!server) + return NULL; + + assert(server->n_ref >= 1); + server->n_ref++; return server; } -unsigned long client_id_hash_func(const void *p, - const uint8_t hash_key[HASH_KEY_SIZE]) { - uint64_t u; +void client_id_hash_func(const void *p, struct siphash *state) { const DHCPClientId *id = p; assert(id); assert(id->length); assert(id->data); - siphash24((uint8_t*) &u, id->data, id->length, hash_key); - - return (unsigned long) u; + 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) { @@ -127,7 +155,10 @@ sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) { if (!server) return NULL; - if (REFCNT_DEC(server->n_ref) > 0) + assert(server->n_ref >= 1); + server->n_ref--; + + if (server->n_ref > 0) return NULL; log_dhcp_server(server, "UNREF"); @@ -136,6 +167,10 @@ sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *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); @@ -156,13 +191,15 @@ int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) { if (!server) return -ENOMEM; - server->n_ref = REFCNT_INIT; + server->n_ref = 1; server->fd_raw = -1; server->fd = -1; server->address = htobe32(INADDR_ANY); server->netmask = htobe32(INADDR_ANY); - server->index = ifindex; + 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; @@ -223,13 +260,12 @@ static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, union sockaddr_union link = { .ll.sll_family = AF_PACKET, .ll.sll_protocol = htons(ETH_P_IP), - .ll.sll_ifindex = server->index, + .ll.sll_ifindex = server->ifindex, .ll.sll_halen = ETH_ALEN, }; - int r; assert(server); - assert(server->index > 0); + assert(server->ifindex > 0); assert(server->address); assert(packet); assert(len > sizeof(DHCPPacket)); @@ -240,11 +276,7 @@ static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, packet->dhcp.yiaddr, DHCP_PORT_CLIENT, len); - r = dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len); - if (r < 0) - return r; - - return 0; + 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, @@ -290,7 +322,7 @@ static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, pktinfo = (struct in_pktinfo*) CMSG_DATA(cmsg); assert(pktinfo); - pktinfo->ipi_ifindex = server->index; + pktinfo->ipi_ifindex = server->ifindex; pktinfo->ipi_spec_dst.s_addr = server->address; r = sendmsg(server->fd, &msg, 0); @@ -474,6 +506,33 @@ static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req, if (r < 0) return r; + if (server->n_dns > 0) { + r = dhcp_option_append( + &packet->dhcp, req->max_optlen, &offset, 0, + 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, + 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, + 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; @@ -490,11 +549,7 @@ static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) { if (r < 0) return r; - r = dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset); - if (r < 0) - return r; - - return 0; + return dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset); } static int server_send_forcerenew(sd_dhcp_server *server, be32_t address, @@ -532,9 +587,8 @@ static int server_send_forcerenew(sd_dhcp_server *server, be32_t address, return 0; } -static int parse_request(uint8_t code, uint8_t len, const uint8_t *option, - void *user_data) { - DHCPRequest *req = user_data; +static int parse_request(uint8_t code, uint8_t len, const void *option, void *userdata) { + DHCPRequest *req = userdata; assert(req); @@ -590,7 +644,7 @@ static void dhcp_request_free(DHCPRequest *req) { DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPRequest*, dhcp_request_free); #define _cleanup_dhcp_request_free_ _cleanup_(dhcp_request_freep) -static int ensure_sane_request(DHCPRequest *req, DHCPMessage *message) { +static int ensure_sane_request(sd_dhcp_server *server, DHCPRequest *req, DHCPMessage *message) { assert(req); assert(message); @@ -599,23 +653,27 @@ static int ensure_sane_request(DHCPRequest *req, DHCPMessage *message) { /* set client id based on MAC address if client did not send an explicit one */ if (!req->client_id.data) { - uint8_t *data; + void *data; - data = new0(uint8_t, ETH_ALEN + 1); + 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; - req->client_id.data[0] = 0x01; - memcpy(&req->client_id.data[1], &message->chaddr, ETH_ALEN); } if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE) req->max_optlen = DHCP_MIN_OPTIONS_SIZE; - if (!req->lifetime) - req->lifetime = DHCP_DEFAULT_LEASE_TIME; + 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; } @@ -626,14 +684,15 @@ static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) { if (!server->pool_size) return -EINVAL; - if (be32toh(requested_ip) < be32toh(server->pool_start) || - be32toh(requested_ip) >= be32toh(server->pool_start) + - + 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) - be32toh(server->pool_start); + 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; @@ -656,7 +715,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, if (type < 0) return 0; - r = ensure_sane_request(req, message); + r = ensure_sane_request(server, req, message); if (r < 0) /* this only fails on critical errors */ return r; @@ -665,8 +724,8 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, &req->client_id); switch(type) { - case DHCP_DISCOVER: - { + + case DHCP_DISCOVER: { be32_t address = INADDR_ANY; unsigned i; @@ -681,12 +740,25 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, 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); + siphash24_finalize((uint8_t*)&hash, &state); + next_offer = hash % server->pool_size; + for (i = 0; i < server->pool_size; i++) { - if (!server->bound_leases[server->next_offer]) { - address = htobe32(be32toh(server->pool_start) + server->next_offer); + if (!server->bound_leases[next_offer]) { + address = server->subnet | htobe32(server->pool_offset + next_offer); break; } else - server->next_offer = (server->next_offer + 1) % server->pool_size; + next_offer = (next_offer + 1) % server->pool_size; } } @@ -716,9 +788,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, return 1; - break; - case DHCP_REQUEST: - { + case DHCP_REQUEST: { be32_t address; bool init_reboot = false; int pool_offset; @@ -796,8 +866,12 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, r = sd_event_now(server->event, clock_boottime_or_monotonic(), &time_now); - if (r < 0) - time_now = now(clock_boottime_or_monotonic()); + 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); @@ -836,6 +910,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, break; } + case DHCP_RELEASE: { int pool_offset; @@ -879,13 +954,12 @@ static int server_receive_message(sd_event_source *s, int fd, .msg_controllen = sizeof(cmsgbuf), }; struct cmsghdr *cmsg; - int buflen = 0, len, r; + int buflen = 0, len; assert(server); - r = ioctl(fd, FIONREAD, &buflen); - if (r < 0) - return r; + if (ioctl(fd, FIONREAD, &buflen) < 0) + return -errno; if (buflen < 0) return -EIO; @@ -910,7 +984,7 @@ static int server_receive_message(sd_event_source *s, int fd, /* TODO figure out if this can be done as a filter on * the socket, like for IPv6 */ - if (server->index != info->ipi_ifindex) + if (server->ifindex != info->ipi_ifindex) return 0; break; @@ -975,7 +1049,7 @@ int sd_dhcp_server_forcerenew(sd_dhcp_server *server) { for (i = 0; i < server->pool_size; i++) { DHCPLease *lease = server->bound_leases[i]; - if (!lease) + if (!lease || lease == &server->invalid_lease) continue; r = server_send_forcerenew(server, lease->address, @@ -989,3 +1063,91 @@ int sd_dhcp_server_forcerenew(sd_dhcp_server *server) { 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; +} |