[systemd-devel] [PATCH v2] networkd: send hostname to dhcp server
Tom Gundersen
teg at jklm.no
Tue Jul 1 13:04:12 PDT 2014
On Tue, Jul 1, 2014 at 8:58 PM, Eugene Yakubovich
<eugene.yakubovich at coreos.com> wrote:
> 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 [DHCPv4]
> section of .network file
Pushed with minor modifications. Please check that it still works ok for you.
Thanks!
Tom
> man/systemd.network.xml | 7 ++++++
> src/libsystemd-network/sd-dhcp-client.c | 41 ++++++++++++++++++++++++++++++++
> src/network/networkd-link.c | 25 +++++++++++++++++++
> src/network/networkd-network-gperf.gperf | 1 +
> src/network/networkd-network.c | 1 +
> src/network/networkd.h | 1 +
> src/systemd/sd-dhcp-client.h | 1 +
> 7 files changed, 77 insertions(+)
>
> diff --git a/man/systemd.network.xml b/man/systemd.network.xml
> index 8b2dd2f..906086b 100644
> --- a/man/systemd.network.xml
> +++ b/man/systemd.network.xml
> @@ -380,6 +380,13 @@
> </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>
> <para>When true (the default), the hostname received from the DHCP server
> diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
> index 1603c41..c278bb7 100644
> --- a/src/libsystemd-network/sd-dhcp-client.c
> +++ b/src/libsystemd-network/sd-dhcp-client.c
> @@ -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 +179,26 @@ 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) {
> +
> + assert_return(client, -EINVAL);
> +
> + if (streq_ptr(client->hostname, hostname))
> + return 0;
> +
> + free(client->hostname);
> +
> + if (hostname) {
> + client->hostname = strdup(hostname);
> + if (!client->hostname)
> + return -ENOMEM;
> + } else
> + client->hostname = NULL;
> +
> + 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 +407,17 @@ 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 +509,14 @@ 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)
> @@ -1363,6 +1403,7 @@ 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);
> }
>
> diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
> index 9296a59..e573502 100644
> --- a/src/network/networkd-link.c
> +++ b/src/network/networkd-link.c
> @@ -21,6 +21,7 @@
>
> #include <netinet/ether.h>
> #include <linux/if.h>
> +#include <unistd.h>
>
> #include "networkd.h"
> #include "libudev-private.h"
> @@ -1846,6 +1847,18 @@ 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;
>
> @@ -1911,6 +1924,18 @@ 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) {
> diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
> index 469e028..6abef51 100644
> --- a/src/network/networkd-network-gperf.gperf
> +++ b/src/network/networkd-network-gperf.gperf
> @@ -48,4 +48,5 @@ DHCPv4.UseDNS, config_parse_bool, 0,
> 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.SendHostname, config_parse_bool, 0, offsetof(Network, dhcp_sendhost)
> DHCPv4.CriticalConnection, config_parse_bool, 0, offsetof(Network, dhcp_critical)
> diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
> index 8e7cdf6..0291b5a 100644
> --- a/src/network/networkd-network.c
> +++ b/src/network/networkd-network.c
> @@ -89,6 +89,7 @@ static int network_load_one(Manager *manager, const char *filename) {
> network->dhcp_dns = true;
> network->dhcp_hostname = true;
> network->dhcp_domainname = 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);
> diff --git a/src/network/networkd.h b/src/network/networkd.h
> index b7b1d90..3667e46 100644
> --- a/src/network/networkd.h
> +++ b/src/network/networkd.h
> @@ -159,6 +159,7 @@ struct Network {
> bool dhcp_mtu;
> bool dhcp_hostname;
> bool dhcp_domainname;
> + bool dhcp_sendhost;
> bool dhcp_critical;
> bool ipv4ll;
> bool dhcp6;
> diff --git a/src/systemd/sd-dhcp-client.h b/src/systemd/sd-dhcp-client.h
> index 5818ec4..7b5b938 100644
> --- a/src/systemd/sd-dhcp-client.h
> +++ b/src/systemd/sd-dhcp-client.h
> @@ -50,6 +50,7 @@ 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);
> --
> 1.9.1
>
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