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networkd: send hostname to dhcp server 

Send hostname (option 12) in DISCOVER and REQUEST messages so the
DHCP server could use it to register with dynamic DNS and such.

To opt-out of this behaviour set SendHostname to false in [DHCP]
section of .network file

[tomegun: rebased, made sure a failing set_hostname is a noop and moved
          config from DHCPv4 to DHCP]
This commit is contained in:
Eugene Yakubovich 2014-07-01 11:58:49 -07:00 committed by Tom Gundersen
parent 0a8a0fad01
commit 4cc7a82c94
7 changed files with 81 additions and 2 deletions
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7
man/systemd.network.xml
View File

@ -404,6 +404,13 @@
be used on the current link. Defaults to false.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>SendHostname=</varname></term>
<listitem>
<para>When true (the default), the machine's hostname will be sent to the DHCP
server</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>UseHostname=</varname></term>
<listitem>

42
src/libsystemd-network/sd-dhcp-client.c
View File

@ -56,6 +56,7 @@ struct sd_dhcp_client {
uint8_t type;
struct ether_addr mac_addr;
} _packed_ client_id;
char *hostname;
uint32_t xid;
usec_t start_time;
uint16_t secs;
@ -178,6 +179,27 @@ int sd_dhcp_client_set_mac(sd_dhcp_client *client,
return 0;
}
int sd_dhcp_client_set_hostname(sd_dhcp_client *client,
const char *hostname) {
char *new_hostname = NULL;
assert_return(client, -EINVAL);
if (streq_ptr(client->hostname, hostname))
return 0;
if (hostname) {
new_hostname = strdup(hostname);
if (!new_hostname)
return -ENOMEM;
}
free(client->hostname);
client->hostname = new_hostname;
return 0;
}
int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
assert_return(client, -EINVAL);
assert_return(ret, -EINVAL);
@ -386,6 +408,17 @@ static int client_send_discover(sd_dhcp_client *client) {
return r;
}
/* it is unclear from RFC 2131 if client should send hostname in
DHCPDISCOVER but dhclient does and so we do as well
*/
if (client->hostname) {
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_HOST_NAME,
strlen(client->hostname), client->hostname);
if (r < 0)
return r;
}
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_END, 0, NULL);
if (r < 0)
@ -477,6 +510,14 @@ static int client_send_request(sd_dhcp_client *client) {
return -EINVAL;
}
if (client->hostname) {
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_HOST_NAME,
strlen(client->hostname), client->hostname);
if (r < 0)
return r;
}
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_END, 0, NULL);
if (r < 0)
@ -1364,6 +1405,7 @@ sd_dhcp_client *sd_dhcp_client_unref(sd_dhcp_client *client) {
sd_dhcp_lease_unref(client->lease);
free(client->req_opts);
free(client->hostname);
free(client);
}

26
src/network/networkd-link.c
View File

@ -21,6 +21,7 @@
#include <netinet/ether.h>
#include <linux/if.h>
#include <unistd.h>
#include "networkd.h"
#include "libudev-private.h"
@ -1927,6 +1928,18 @@ static int link_enter_enslave(Link *link) {
return 0;
}
/* make sure the hostname is not "localhost" */
static bool is_localhost(const char *hostname) {
assert(hostname);
return streq(hostname, "localhost") ||
streq(hostname, "localhost.") ||
endswith(hostname, ".localhost") ||
endswith(hostname, ".localhost.") ||
endswith(hostname, ".localdomain") ||
endswith(hostname, ".localdomain.");
}
static int link_configure(Link *link) {
int r;
@ -1992,6 +2005,7 @@ static int link_configure(Link *link) {
if (r < 0)
return r;
}
if (link->network->dhcp_routes) {
r = sd_dhcp_client_set_request_option(link->dhcp_client, DHCP_OPTION_STATIC_ROUTE);
if (r < 0)
@ -2000,6 +2014,18 @@ static int link_configure(Link *link) {
if (r < 0)
return r;
}
if (link->network->dhcp_sendhost) {
_cleanup_free_ char *hostname = gethostname_malloc();
if (!hostname)
return -ENOMEM;
if (!is_localhost(hostname)) {
r = sd_dhcp_client_set_hostname(link->dhcp_client, hostname);
if (r < 0)
return r;
}
}
}
if (link->network->dhcp_server) {

5
src/network/networkd-network-gperf.gperf
View File

@ -47,11 +47,12 @@ DHCP.UseDNS, config_parse_bool, 0,
DHCP.UseMTU, config_parse_bool, 0, offsetof(Network, dhcp_mtu)
DHCP.UseHostname, config_parse_bool, 0, offsetof(Network, dhcp_hostname)
DHCP.UseDomainName, config_parse_bool, 0, offsetof(Network, dhcp_domainname)
DHCP.UseRoutes, config_parse_bool, 0, offsetof(Network, dhcp_routes)
DHCP.SendHostname, config_parse_bool, 0, offsetof(Network, dhcp_sendhost)
DHCP.CriticalConnection, config_parse_bool, 0, offsetof(Network, dhcp_critical)
/* backwards compatibility */
/* backwards compatibility: do not add new entries to this section */
DHCPv4.UseDNS, config_parse_bool, 0, offsetof(Network, dhcp_dns)
DHCPv4.UseMTU, config_parse_bool, 0, offsetof(Network, dhcp_mtu)
DHCPv4.UseHostname, config_parse_bool, 0, offsetof(Network, dhcp_hostname)
DHCPv4.UseDomainName, config_parse_bool, 0, offsetof(Network, dhcp_domainname)
DHCPv4.UseRoutes, config_parse_bool, 0, offsetof(Network, dhcp_routes)
DHCPv4.CriticalConnection, config_parse_bool, 0, offsetof(Network, dhcp_critical)

1
src/network/networkd-network.c
View File

@ -90,6 +90,7 @@ static int network_load_one(Manager *manager, const char *filename) {
network->dhcp_hostname = true;
network->dhcp_domainname = true;
network->dhcp_routes = true;
network->dhcp_sendhost = true;
r = config_parse(NULL, filename, file, "Match\0Network\0Address\0Route\0DHCPv4\0", config_item_perf_lookup,
(void*) network_network_gperf_lookup, false, false, network);

1
src/network/networkd.h
View File

@ -169,6 +169,7 @@ struct Network {
bool dhcp_mtu;
bool dhcp_hostname;
bool dhcp_domainname;
bool dhcp_sendhost;
bool dhcp_critical;
bool dhcp_routes;
bool ipv4ll;

1
src/systemd/sd-dhcp-client.h
View File

@ -51,6 +51,7 @@ int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index);
int sd_dhcp_client_set_mac(sd_dhcp_client *client,
const struct ether_addr *addr);
int sd_dhcp_client_set_hostname(sd_dhcp_client *client, const char *hostname);
int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret);
int sd_dhcp_client_stop(sd_dhcp_client *client);