Send hostname (option 12) in DISCOVER and REQUEST messages so the
DHCP server could use it to register with dynamic DNS and such.
---
src/libsystemd-network/sd-dhcp-client.c | 35 +++++++++++++++++++++++++++++++++
src/network/networkd-link.c | 26 ++++++++++++++++++++++++
src/systemd/sd-dhcp-client.h | 1 +
3 files changed, 62 insertions(+)
diff --git a/src/libsystemd-network/sd-dhcp-client.c
b/src/libsystemd-network/sd-dhcp-client.c
index 1603c41..44a5e8a 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 +179,20 @@ 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);
+ assert_return(hostname, -EINVAL);
+
+ if (client->hostname && streq(client->hostname, hostname) )
+ return 0;
+
+ client->hostname = strdup(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 +401,17 @@ 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 +503,14 @@ 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 +1397,7 @@ 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..9d849a0 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 +1847,19 @@ static int link_enter_enslave(Link *link) {
return 0;
}
+/* make sure the hostname is not "localhost" */
+static bool is_localhost(const char *hostname) {
+ char *hostend;
+
+ assert(hostname);
+
+ hostend = strchr(hostname, '.');
+ if (hostend)
+ return strneq(hostname, "localhost", (hostend - hostname));
+ else
+ return streq(hostname, "localhost");
+}
+
static int link_configure(Link *link) {
int r;
@@ -1886,6 +1900,8 @@ static int link_configure(Link *link) {
}
if (link->network->dhcp) {
+ char hostname[HOST_NAME_MAX];
+
r = sd_dhcp_client_new(&link->dhcp_client);
if (r < 0)
return r;
@@ -1911,6 +1927,16 @@ static int link_configure(Link *link) {
if (r < 0)
return r;
}
+
+ r = gethostname(hostname, sizeof(hostname));
+ if (r < 0)
+ return r;
+
+ 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/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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