diff options
Diffstat (limited to 'src/network/networkd-dhcp-server.c')
| -rw-r--r-- | src/network/networkd-dhcp-server.c | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/src/network/networkd-dhcp-server.c b/src/network/networkd-dhcp-server.c new file mode 100644 index 0000000..cf279c6 --- /dev/null +++ b/src/network/networkd-dhcp-server.c @@ -0,0 +1,439 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <netinet/in.h> +#include <linux/if_arp.h> +#include <linux/if.h> + +#include "sd-dhcp-server.h" + +#include "fd-util.h" +#include "fileio.h" +#include "networkd-address.h" +#include "networkd-dhcp-server.h" +#include "networkd-link.h" +#include "networkd-manager.h" +#include "networkd-network.h" +#include "parse-util.h" +#include "socket-netlink.h" +#include "string-table.h" +#include "string-util.h" +#include "strv.h" + +static bool link_dhcp4_server_enabled(Link *link) { + assert(link); + + if (link->flags & IFF_LOOPBACK) + return false; + + if (!link->network) + return false; + + if (link->network->bond) + return false; + + if (link->iftype == ARPHRD_CAN) + return false; + + return link->network->dhcp_server; +} + +static Address* link_find_dhcp_server_address(Link *link) { + Address *address; + + assert(link); + assert(link->network); + + /* The first statically configured address if there is any */ + ORDERED_HASHMAP_FOREACH(address, link->network->addresses_by_section) + if (address->family == AF_INET && + !in_addr_is_null(address->family, &address->in_addr)) + return address; + + /* If that didn't work, find a suitable address we got from the pool */ + SET_FOREACH(address, link->pool_addresses) + if (address->family == AF_INET) + return address; + + return NULL; +} + +static int link_push_uplink_to_dhcp_server( + Link *link, + sd_dhcp_lease_server_type what, + sd_dhcp_server *s) { + + _cleanup_free_ struct in_addr *addresses = NULL; + size_t n_addresses = 0, n_allocated = 0; + bool use_dhcp_lease_data = true; + + assert(link); + + if (!link->network) + return 0; + assert(link->network); + + log_link_debug(link, "Copying %s from link", dhcp_lease_server_type_to_string(what)); + + switch (what) { + + case SD_DHCP_LEASE_DNS: + /* For DNS we have a special case. We the data configured explicitly locally along with the + * data from the DHCP lease. */ + + for (unsigned i = 0; i < link->network->n_dns; i++) { + struct in_addr ia; + + /* Only look for IPv4 addresses */ + if (link->network->dns[i]->family != AF_INET) + continue; + + ia = link->network->dns[i]->address.in; + + /* Never propagate obviously borked data */ + if (in4_addr_is_null(&ia) || in4_addr_is_localhost(&ia)) + continue; + + if (!GREEDY_REALLOC(addresses, n_allocated, n_addresses + 1)) + return log_oom(); + + addresses[n_addresses++] = ia; + } + + use_dhcp_lease_data = link->network->dhcp_use_dns; + break; + + case SD_DHCP_LEASE_NTP: { + char **i; + + /* For NTP things are similar, but for NTP hostnames can be configured too, which we cannot + * propagate via DHCP. Hence let's only propagate those which are IP addresses. */ + + STRV_FOREACH(i, link->network->ntp) { + union in_addr_union ia; + + if (in_addr_from_string(AF_INET, *i, &ia) < 0) + continue; + + /* Never propagate obviously borked data */ + if (in4_addr_is_null(&ia.in) || in4_addr_is_localhost(&ia.in)) + continue; + + if (!GREEDY_REALLOC(addresses, n_allocated, n_addresses + 1)) + return log_oom(); + + addresses[n_addresses++] = ia.in; + } + + use_dhcp_lease_data = link->network->dhcp_use_ntp; + break; + } + + case SD_DHCP_LEASE_SIP: + + /* For SIP we don't allow explicit, local configuration, but there's control whether to use the data */ + use_dhcp_lease_data = link->network->dhcp_use_sip; + break; + + case SD_DHCP_LEASE_POP3: + case SD_DHCP_LEASE_SMTP: + case SD_DHCP_LEASE_LPR: + /* For the other server types we currently do not allow local configuration of server data, + * since there are typically no local consumers of the data. */ + break; + + default: + assert_not_reached("Unexpected server type"); + } + + if (use_dhcp_lease_data && link->dhcp_lease) { + const struct in_addr *da; + + int n = sd_dhcp_lease_get_servers(link->dhcp_lease, what, &da); + if (n > 0) { + if (!GREEDY_REALLOC(addresses, n_allocated, n_addresses + n)) + return log_oom(); + + for (int j = 0; j < n; j++) + if (in4_addr_is_non_local(&da[j])) + addresses[n_addresses++] = da[j]; + } + } + + if (n_addresses <= 0) + return 0; + + return sd_dhcp_server_set_servers(s, what, addresses, n_addresses); +} + +static int dhcp4_server_parse_dns_server_string_and_warn(Link *l, const char *string, struct in_addr **addresses, size_t *n_allocated, size_t *n_addresses) { + for (;;) { + _cleanup_free_ char *word = NULL, *server_name = NULL; + union in_addr_union address; + int family, r, ifindex = 0; + + r = extract_first_word(&string, &word, NULL, 0); + if (r < 0) + return r; + if (r == 0) + break; + + r = in_addr_ifindex_name_from_string_auto(word, &family, &address, &ifindex, &server_name); + if (r < 0) { + log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring: %m", word); + continue; + } + + /* Only look for IPv4 addresses */ + if (family != AF_INET) + continue; + + /* Never propagate obviously borked data */ + if (in4_addr_is_null(&address.in) || in4_addr_is_localhost(&address.in)) + continue; + + if (!GREEDY_REALLOC(*addresses, *n_allocated, *n_addresses + 1)) + return log_oom(); + + (*addresses)[(*n_addresses)++] = address.in; + } + + return 0; +} + +static int dhcp4_server_set_dns_from_resolve_conf(Link *link) { + _cleanup_free_ struct in_addr *addresses = NULL; + size_t n_addresses = 0, n_allocated = 0; + _cleanup_fclose_ FILE *f = NULL; + int n = 0, r; + + f = fopen(PRIVATE_UPLINK_RESOLV_CONF, "re"); + if (!f) { + if (errno == ENOENT) + return 0; + + return log_warning_errno(errno, "Failed to open " PRIVATE_UPLINK_RESOLV_CONF ": %m"); + } + + for (;;) { + _cleanup_free_ char *line = NULL; + const char *a; + char *l; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return log_error_errno(r, "Failed to read " PRIVATE_UPLINK_RESOLV_CONF ": %m"); + if (r == 0) + break; + + n++; + + l = strstrip(line); + if (IN_SET(*l, '#', ';', 0)) + continue; + + a = first_word(l, "nameserver"); + if (!a) + continue; + + r = dhcp4_server_parse_dns_server_string_and_warn(link, a, &addresses, &n_allocated, &n_addresses); + if (r < 0) + log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a); + } + + if (n_addresses <= 0) + return 0; + + return sd_dhcp_server_set_dns(link->dhcp_server, addresses, n_addresses); +} + +int dhcp4_server_configure(Link *link) { + bool acquired_uplink = false; + sd_dhcp_option *p; + Link *uplink = NULL; + Address *address; + int r; + + assert(link); + + if (!link_dhcp4_server_enabled(link)) + return 0; + + if (!(link->flags & IFF_UP)) + return 0; + + if (!link->dhcp_server) { + r = sd_dhcp_server_new(&link->dhcp_server, link->ifindex); + if (r < 0) + return r; + + r = sd_dhcp_server_attach_event(link->dhcp_server, link->manager->event, 0); + if (r < 0) + return r; + } + + address = link_find_dhcp_server_address(link); + if (!address) + return log_link_error_errno(link, SYNTHETIC_ERRNO(EBUSY), + "Failed to find suitable address for DHCPv4 server instance."); + + /* use the server address' subnet as the pool */ + r = sd_dhcp_server_configure_pool(link->dhcp_server, &address->in_addr.in, address->prefixlen, + link->network->dhcp_server_pool_offset, link->network->dhcp_server_pool_size); + if (r < 0) + return log_link_error_errno(link, r, "Failed to configure address pool for DHCPv4 server instance: %m"); + + /* TODO: + r = sd_dhcp_server_set_router(link->dhcp_server, &main_address->in_addr.in); + if (r < 0) + return r; + */ + + if (link->network->dhcp_server_max_lease_time_usec > 0) { + r = sd_dhcp_server_set_max_lease_time(link->dhcp_server, + DIV_ROUND_UP(link->network->dhcp_server_max_lease_time_usec, USEC_PER_SEC)); + if (r < 0) + return log_link_error_errno(link, r, "Failed to set maximum lease time for DHCPv4 server instance: %m"); + } + + if (link->network->dhcp_server_default_lease_time_usec > 0) { + r = sd_dhcp_server_set_default_lease_time(link->dhcp_server, + DIV_ROUND_UP(link->network->dhcp_server_default_lease_time_usec, USEC_PER_SEC)); + if (r < 0) + return log_link_error_errno(link, r, "Failed to set default lease time for DHCPv4 server instance: %m"); + } + + for (sd_dhcp_lease_server_type type = 0; type < _SD_DHCP_LEASE_SERVER_TYPE_MAX; type ++) { + + if (!link->network->dhcp_server_emit[type].emit) + continue; + + if (link->network->dhcp_server_emit[type].n_addresses > 0) + /* Explicitly specified servers to emit */ + r = sd_dhcp_server_set_servers( + link->dhcp_server, + type, + link->network->dhcp_server_emit[type].addresses, + link->network->dhcp_server_emit[type].n_addresses); + else { + /* Emission is requested, but nothing explicitly configured. Let's find a suitable upling */ + if (!acquired_uplink) { + uplink = manager_find_uplink(link->manager, link); + acquired_uplink = true; + } + + if (uplink && uplink->network) + r = link_push_uplink_to_dhcp_server(uplink, type, link->dhcp_server); + else if (type == SD_DHCP_LEASE_DNS) + r = dhcp4_server_set_dns_from_resolve_conf(link); + else { + log_link_debug(link, + "Not emitting %s on link, couldn't find suitable uplink.", + dhcp_lease_server_type_to_string(type)); + continue; + } + } + + if (r < 0) + log_link_warning_errno(link, r, + "Failed to set %s for DHCP server, ignoring: %m", + dhcp_lease_server_type_to_string(type)); + } + + r = sd_dhcp_server_set_emit_router(link->dhcp_server, link->network->dhcp_server_emit_router); + if (r < 0) + return log_link_error_errno(link, r, "Failed to set router emission for DHCP server: %m"); + + if (link->network->dhcp_server_emit_timezone) { + _cleanup_free_ char *buffer = NULL; + const char *tz; + + if (link->network->dhcp_server_timezone) + tz = link->network->dhcp_server_timezone; + else { + r = get_timezone(&buffer); + if (r < 0) + return log_link_error_errno(link, r, "Failed to determine timezone: %m"); + + tz = buffer; + } + + r = sd_dhcp_server_set_timezone(link->dhcp_server, tz); + if (r < 0) + return log_link_error_errno(link, r, "Failed to set timezone for DHCP server: %m"); + } + + ORDERED_HASHMAP_FOREACH(p, link->network->dhcp_server_send_options) { + r = sd_dhcp_server_add_option(link->dhcp_server, p); + if (r == -EEXIST) + continue; + if (r < 0) + return log_link_error_errno(link, r, "Failed to set DHCPv4 option: %m"); + } + + ORDERED_HASHMAP_FOREACH(p, link->network->dhcp_server_send_vendor_options) { + r = sd_dhcp_server_add_vendor_option(link->dhcp_server, p); + if (r == -EEXIST) + continue; + if (r < 0) + return log_link_error_errno(link, r, "Failed to set DHCPv4 option: %m"); + } + + if (!sd_dhcp_server_is_running(link->dhcp_server)) { + r = sd_dhcp_server_start(link->dhcp_server); + if (r < 0) + return log_link_error_errno(link, r, "Could not start DHCPv4 server instance: %m"); + + log_link_debug(link, "Offering DHCPv4 leases"); + } + + return 0; +} + +int config_parse_dhcp_server_emit( + const char *unit, + const char *filename, + unsigned line, + const char *section, + unsigned section_line, + const char *lvalue, + int ltype, + const char *rvalue, + void *data, + void *userdata) { + + NetworkDHCPServerEmitAddress *emit = data; + + assert(emit); + assert(rvalue); + + for (const char *p = rvalue;;) { + _cleanup_free_ char *w = NULL; + union in_addr_union a; + int r; + + r = extract_first_word(&p, &w, NULL, 0); + if (r == -ENOMEM) + return log_oom(); + if (r < 0) { + log_syntax(unit, LOG_WARNING, filename, line, r, + "Failed to extract word, ignoring: %s", rvalue); + return 0; + } + if (r == 0) + return 0; + + r = in_addr_from_string(AF_INET, w, &a); + if (r < 0) { + log_syntax(unit, LOG_WARNING, filename, line, r, + "Failed to parse %s= address '%s', ignoring: %m", lvalue, w); + continue; + } + + struct in_addr *m = reallocarray(emit->addresses, emit->n_addresses + 1, sizeof(struct in_addr)); + if (!m) + return log_oom(); + + emit->addresses = m; + emit->addresses[emit->n_addresses++] = a.in; + } +} |