[systemd-devel] [PATCH] sd-dhcp6-client: support custom DUIDs
Tom Gundersen
teg at jklm.no
Mon Aug 11 16:12:23 PDT 2014
On Wed, Aug 6, 2014 at 6:17 PM, Dan Williams <dcbw at redhat.com> wrote:
> The caller may have an existing DUID that it wants to use, and may
> want to use some other DUID generation scheme than systemd's
> default DUID-EN.
I have no objections a priori to this patch. But what is the use case?
Is there some DUID scheme that is preferable to DUID-EN that we could
simply use unconditionally, or do you really depend on the possibility
of customizing it?
> ---
> src/libsystemd-network/sd-dhcp6-client.c | 52 +++++++++++++++++++-----------
> src/libsystemd-network/test-dhcp6-client.c | 4 +--
> src/network/networkd-link.c | 2 +-
> src/systemd/sd-dhcp6-client.h | 2 +-
> 4 files changed, 38 insertions(+), 22 deletions(-)
>
> diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
> index c6c82eb..8123dc8 100644
> --- a/src/libsystemd-network/sd-dhcp6-client.c
> +++ b/src/libsystemd-network/sd-dhcp6-client.c
> @@ -35,14 +35,16 @@
> #include "dhcp6-protocol.h"
> #include "dhcp6-internal.h"
> #include "dhcp6-lease-internal.h"
>
> #define SYSTEMD_PEN 43793
> #define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
>
> +#define MAX_DUID_LEN 32
> +
> struct sd_dhcp6_client {
> RefCount n_ref;
>
> enum DHCP6State state;
> sd_event *event;
> int event_priority;
> int index;
> @@ -57,20 +59,16 @@ struct sd_dhcp6_client {
> sd_event_source *receive_message;
> usec_t retransmit_time;
> uint8_t retransmit_count;
> sd_event_source *timeout_resend;
> sd_event_source *timeout_resend_expire;
> sd_dhcp6_client_cb_t cb;
> void *userdata;
> -
> - struct duid_en {
> - uint16_t type; /* DHCP6_DUID_EN */
> - uint32_t pen;
> - uint8_t id[8];
> - } _packed_ duid;
> + uint8_t duid[MAX_DUID_LEN];
> + size_t duid_len;
> };
>
> static const uint16_t default_req_opts[] = {
> DHCP6_OPTION_DNS_SERVERS,
> DHCP6_OPTION_DOMAIN_LIST,
> DHCP6_OPTION_NTP_SERVER,
> };
> @@ -300,15 +298,15 @@ static int client_send_message(sd_dhcp6_client *client) {
> r = dhcp6_option_append(&opt, &optlen, DHCP6_OPTION_ORO,
> client->req_opts_len * sizeof(be16_t),
> client->req_opts);
> if (r < 0)
> return r;
>
> r = dhcp6_option_append(&opt, &optlen, DHCP6_OPTION_CLIENTID,
> - sizeof(client->duid), &client->duid);
> + client->duid_len, &client->duid);
> if (r < 0)
> return r;
>
> r = dhcp6_network_send_udp_socket(client->fd, &all_servers, message,
> len - optlen);
> if (r < 0)
> return r;
> @@ -585,15 +583,15 @@ static int client_parse_message(sd_dhcp6_client *client,
> case DHCP6_OPTION_CLIENTID:
> if (clientid) {
> log_dhcp6_client(client, "%s contains multiple clientids",
> dhcp6_message_type_to_string(message->type));
> return -EINVAL;
> }
>
> - if (optlen != sizeof(client->duid) ||
> + if (optlen != client->duid_len ||
> memcmp(&client->duid, optval, optlen) != 0) {
> log_dhcp6_client(client, "%s DUID does not match",
> dhcp6_message_type_to_string(message->type));
>
> return -EINVAL;
> }
> clientid = true;
> @@ -1059,47 +1057,65 @@ sd_dhcp6_client *sd_dhcp6_client_unref(sd_dhcp6_client *client) {
>
> return NULL;
> }
>
> return client;
> }
>
> -int sd_dhcp6_client_new(sd_dhcp6_client **ret)
> +struct duid_en {
> + uint16_t type; /* DHCP6_DUID_EN */
> + uint32_t pen;
> + uint8_t id[8];
> +} _packed_;
> +
> +int sd_dhcp6_client_new(sd_dhcp6_client **ret, uint8_t *duid, size_t duid_len)
> {
> _cleanup_dhcp6_client_unref_ sd_dhcp6_client *client = NULL;
> sd_id128_t machine_id;
> int r;
> size_t t;
>
> assert_return(ret, -EINVAL);
> + if (duid)
> + assert_return(duid_len > 0 && duid_len < MAX_DUID_LEN, -EINVAL);
> + else
> + assert_return(duid_len == 0, -EINVAL);
>
> client = new0(sd_dhcp6_client, 1);
> if (!client)
> return -ENOMEM;
>
> client->n_ref = REFCNT_INIT;
>
> client->ia_na.type = DHCP6_OPTION_IA_NA;
>
> client->index = -1;
>
> client->fd = -1;
>
> /* initialize DUID */
> - client->duid.type = htobe16(DHCP6_DUID_EN);
> - client->duid.pen = htobe32(SYSTEMD_PEN);
> + if (duid) {
> + memcpy(&client->duid, duid, duid_len);
> + client->duid_len = duid_len;
> + } else {
> + struct duid_en *en = (struct duid_en *) &client->duid;
>
> - r = sd_id128_get_machine(&machine_id);
> - if (r < 0)
> - return r;
> + en->type = htobe16(DHCP6_DUID_EN);
> + en->pen = htobe32(SYSTEMD_PEN);
>
> - /* a bit of snake-oil perhaps, but no need to expose the machine-id
> - directly */
> - siphash24(client->duid.id, &machine_id, sizeof(machine_id),
> - HASH_KEY.bytes);
> + r = sd_id128_get_machine(&machine_id);
> + if (r < 0)
> + return r;
> +
> + /* a bit of snake-oil perhaps, but no need to expose the
> + machine-id directly */
> + siphash24(en->id, &machine_id, sizeof(machine_id),
> + HASH_KEY.bytes);
> + client->duid_len = sizeof (*en);
> + }
>
> client->req_opts_len = ELEMENTSOF(default_req_opts);
>
> client->req_opts = new0(be16_t, client->req_opts_len);
> if (!client->req_opts)
> return -ENOMEM;
>
> diff --git a/src/libsystemd-network/test-dhcp6-client.c b/src/libsystemd-network/test-dhcp6-client.c
> index 96c68e1..3545935 100644
> --- a/src/libsystemd-network/test-dhcp6-client.c
> +++ b/src/libsystemd-network/test-dhcp6-client.c
> @@ -52,15 +52,15 @@ static uint8_t test_duid[14] = { };
>
> static int test_client_basic(sd_event *e) {
> sd_dhcp6_client *client;
>
> if (verbose)
> printf("* %s\n", __FUNCTION__);
>
> - assert_se(sd_dhcp6_client_new(&client) >= 0);
> + assert_se(sd_dhcp6_client_new(&client, NULL, 0) >= 0);
> assert_se(client);
>
> assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
>
> assert_se(sd_dhcp6_client_set_index(client, 15) == 0);
> assert_se(sd_dhcp6_client_set_index(client, -42) == -EINVAL);
> assert_se(sd_dhcp6_client_set_index(client, -1) == 0);
> @@ -538,15 +538,15 @@ static void test_client_solicit_cb(sd_dhcp6_client *client, int event,
> static int test_client_solicit(sd_event *e) {
> sd_dhcp6_client *client;
> usec_t time_now = now(clock_boottime_or_monotonic());
>
> if (verbose)
> printf("* %s\n", __FUNCTION__);
>
> - assert_se(sd_dhcp6_client_new(&client) >= 0);
> + assert_se(sd_dhcp6_client_new(&client, NULL, 0) >= 0);
> assert_se(client);
>
> assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
>
> assert_se(sd_dhcp6_client_set_index(client, test_index) == 0);
> assert_se(sd_dhcp6_client_set_mac(client, &mac_addr) >= 0);
>
> diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
> index accb42b..eff14ca 100644
> --- a/src/network/networkd-link.c
> +++ b/src/network/networkd-link.c
> @@ -1367,15 +1367,15 @@ static void icmp6_router_handler(sd_icmp6_nd *nd, int event, void *userdata) {
>
> return;
> }
>
> if (link->dhcp6_client)
> return;
>
> - r = sd_dhcp6_client_new(&link->dhcp6_client);
> + r = sd_dhcp6_client_new(&link->dhcp6_client, NULL, 0);
> if (r < 0)
> return;
>
> r = sd_dhcp6_client_attach_event(link->dhcp6_client, NULL, 0);
> if (r < 0) {
> link->dhcp6_client = sd_dhcp6_client_unref(link->dhcp6_client);
> return;
> diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
> index 93edcc4..b3ec82f 100644
> --- a/src/systemd/sd-dhcp6-client.h
> +++ b/src/systemd/sd-dhcp6-client.h
> @@ -54,10 +54,10 @@ int sd_dhcp6_client_stop(sd_dhcp6_client *client);
> int sd_dhcp6_client_start(sd_dhcp6_client *client);
> int sd_dhcp6_client_attach_event(sd_dhcp6_client *client, sd_event *event,
> int priority);
> int sd_dhcp6_client_detach_event(sd_dhcp6_client *client);
> sd_event *sd_dhcp6_client_get_event(sd_dhcp6_client *client);
> sd_dhcp6_client *sd_dhcp6_client_ref(sd_dhcp6_client *client);
> sd_dhcp6_client *sd_dhcp6_client_unref(sd_dhcp6_client *client);
> -int sd_dhcp6_client_new(sd_dhcp6_client **ret);
> +int sd_dhcp6_client_new(sd_dhcp6_client **ret, uint8_t *duid, size_t duid_len);
>
> #endif
> --
> 1.9.3
>
>
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