[LEDE-DEV] [PATCH odhcpd] dhcpv4: notify DHCP ack messages via ubus

[Borja Salazar]

Hi,

Our company is currently developing a service for controlling routers
via ubus methods from a server. We also would like to received and
handle different notification from the device, so we would like to
send as many events as possible. Currently there is already a patch
for dnsmasq that provides ubus notifications for DHCP ACK and RELEASE
messages, it would be great if odhcpd implements the same
functionality. To avoid unwanted notifications we could configure ubus
notifications via configuration, or only send them if there is anyone
subscribe to them. Our current use case only needs to know the first
time a client is detected, so this would also work for us.

Let me know what you think

Thanks

Borja


On Mon, Nov 27, 2017 at 10:47 AM, Hans Dedecker <dedeckeh at gmail.com> wrote:
> On Fri, Nov 24, 2017 at 11:56 AM, Borja Salazar <borja.salazar at fon.com> wrote:
>> Signed-off-by: Borja Salazar <borja.salazar at fon.com>
> Hi,
>
> Could you describe why you want an ubus event per sent DHCP ack
> message as potentially this could generate a lot of ubus traffic
> depending on the leasetime and number of connected clients. Depending
> on your use case is it enough to have an ubus event when a clients
> gets active ?
>
> Hans
>> ---
>>  src/dhcpv4.c |  8 ++++++++
>>  src/odhcpd.h |  1 +
>>  src/ubus.c   | 19 +++++++++++++++++++
>>  3 files changed, 28 insertions(+)
>>
>> diff --git a/src/dhcpv4.c b/src/dhcpv4.c
>> index 166582e..ad8d338 100644
>> --- a/src/dhcpv4.c
>> +++ b/src/dhcpv4.c
>> @@ -870,6 +870,14 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
>>                                 req->chaddr[3],req->chaddr[4],req->chaddr[5],
>>                                 inet_ntoa(dest.sin_addr));
>>
>> +#ifdef WITH_UBUS
>> +       if (msg == DHCPV4_MSG_ACK) {
>> +               char mac_str[13];
>> +               memset(&mac_str, 0, sizeof(mac_str));
>> +               odhcpd_hexlify(mac_str, reply.chaddr, ETH_ALEN);
>> +               ubus_event_bcast("dhcp.ack", mac_str, inet_ntoa(reply.yiaddr), hostname, iface->ifname);
>> +       }
>> +#endif
>>         sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
>>                         (struct sockaddr*)&dest, sizeof(dest));
>>  }
>> diff --git a/src/odhcpd.h b/src/odhcpd.h
>> index 45badd3..73e5a49 100644
>> --- a/src/odhcpd.h
>> +++ b/src/odhcpd.h
>> @@ -296,6 +296,7 @@ int ubus_init(void);
>>  const char* ubus_get_ifname(const char *name);
>>  void ubus_apply_network(void);
>>  bool ubus_has_prefix(const char *name, const char *ifname);
>> +void ubus_event_bcast(const char *type, const char *mac, const char *ip, const char *name, const char *interface);
>>  #endif
>>
>>  int netlink_add_netevent_handler(struct netevent_handler *hdlr);
>> diff --git a/src/ubus.c b/src/ubus.c
>> index 95eeff7..e988b8e 100644
>> --- a/src/ubus.c
>> +++ b/src/ubus.c
>> @@ -311,6 +311,25 @@ static const struct blobmsg_policy obj_attrs[OBJ_ATTR_MAX] = {
>>         [OBJ_ATTR_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
>>  };
>>
>> +void ubus_event_bcast(const char *type, const char *mac, const char *ip, const char *name, const char *interface)
>> +{
>> +
>> +       if (!ubus)
>> +               return;
>> +
>> +       blob_buf_init(&b, 0);
>> +       if (mac)
>> +               blobmsg_add_string(&b, "mac", mac);
>> +       if (ip)
>> +               blobmsg_add_string(&b, "ip", ip);
>> +       if (name)
>> +               blobmsg_add_string(&b, "name", name);
>> +       if (interface)
>> +               blobmsg_add_string(&b, "interface", interface);
>> +
>> +       ubus_notify(ubus, &main_object, type, b.head, -1);
>> +
>> +}
>>
>>  static void handle_event(_unused struct ubus_context *ctx, _unused struct ubus_event_handler *ev,
>>                  _unused const char *type, struct blob_attr *msg)
>> --
>> 2.11.0
>>
>>
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