complete DHCP implementation

* convert to lager logging
* fix unicast to client for new clients
* bind to interface
* add namespace support

.gitignore

@@ -0,0 +1,8 @@
+*~
+*.[oa]
+*.beam
+/ebin/*.app
+/priv/*.so
+
+tetrapak/.local.cache
+

c_src/Makefile

@@ -0,0 +1,19 @@
+PRIVDIR := ../priv
+
+LD ?= ld
+CC ?= gcc
+RM ?= rm
+
+CFLAGS ?= -O2
+
+override CFLAGS += -std=gnu99 -Wall -fpic
+override LDFLAGS += -shared -fpic
+
+all : $(PRIVDIR)/dhcp_server.so
+
+$(PRIVDIR)/dhcp_server.so : dhcp_server.o
+	$(CC) $(LDFLAGS) -o $@ $^
+
+clean:
+	$(RM) -f $(PRIVDIR)/dhcp_server.so dhcp_server.o
+

c_src/dhcp_server.c

@@ -0,0 +1,88 @@
+/*
+ *
+ *  Erlang ioctl wrapper to inject ARP entries to kernel
+ *
+ *  Copyright (c) 2011-2012 by Travelping GmbH <[email protected]>
+ *  Copyright (C) <year>  <name of author>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <netinet/in.h>
+
+#include <erl_nif.h>
+#include "erl_driver.h" // for erl_errno_id
+
+static ERL_NIF_TERM atom_error;
+static ERL_NIF_TERM atom_ok;
+
+static ERL_NIF_TERM arp_inject_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+	struct arpreq arp;
+	struct sockaddr_in *in;
+
+	ErlNifBinary ip;
+	int htype;
+	ErlNifBinary addr;
+	ErlNifBinary ifname;
+	int fd;
+
+	if (!enif_inspect_binary(env, argv[0], &ifname)
+	    || ifname.size > 16
+	    || !enif_inspect_binary(env, argv[1], &ip)
+	    || ip.size != 4
+	    || !enif_get_int(env, argv[2], &htype)
+	    || !enif_inspect_binary(env, argv[3], &addr)
+	    || addr.size > 16
+	    || !enif_get_int(env, argv[4], &fd))
+		return enif_make_badarg(env);
+
+	memset(&arp, 0, sizeof(arp));
+	in = (struct sockaddr_in *)&arp.arp_pa;
+	in->sin_family = AF_INET;
+	memcpy(&in->sin_addr.s_addr, ip.data, 4);
+
+	arp.arp_ha.sa_family = htype;
+	memcpy(arp.arp_ha.sa_data, addr.data, addr.size);
+	memcpy(arp.arp_dev, ifname.data, ifname.size);
+	arp.arp_flags = ATF_COM;
+
+	if (ioctl(fd, SIOCSARP, &arp) < 0) {
+		return enif_make_tuple2(env, atom_error, enif_make_atom(env, erl_errno_id(errno)));
+	}
+
+	return atom_ok;
+}
+
+static ErlNifFunc nif_funcs[] = {
+	{"arp_inject_nif", 5, arp_inject_nif}
+};
+
+static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
+{
+	atom_error = enif_make_atom(env,"error");
+	atom_ok = enif_make_atom(env,"ok");
+
+	return 0;
+}
+
+ERL_NIF_INIT(dhcp_server, nif_funcs, load, NULL, NULL, NULL)

priv/dhcp.conf

@@ -3,58 +3,21 @@
 %%%
 
 %%% Global configuration
-%%{server_id, {47,80,19,32}}.
+{server_id, {172,20,48,1}}.
 %%{next_server, {47,80,19,32}}.
+{interface, <<"tap0">>}.
 {authoritative, true}.
-{log_facility, local7}.
-{logfile, "/var/log/dhcp.log"}.
 {lease_file, "/var/run/dhcp_leases.dets"}.
 {netns, "/var/run/netns/core"}.
 
 %%% Hub subnet
 {subnet,
- {192,168,1,0},                       %% Network
+ {172,20,48,0},                       %% Network
  {255,255,255,0},                     %% Netmask
- {{192,168,1,5},{192,168,1,10}},      %% Range
+ {{172,20,48,5},{172,20,48,100}},     %% Range
  [{1,{255,255,255,0}},                %% Subnet Mask
-  {28,{192,168,1,255}},               %% Broadcast Address
-  {3,[{192,168,1,1}]},                %% Routers
-  {15,"us.nortel.com"},               %% Domain Name
-  {6,[{47,80,19,33}]},                %% Domain Name Servers
+  {28,{172,20,48,255}},               %% Broadcast Address
+  {3,[{192,20,48,1}]},                %% Routers
+  {15,"wlan"},                        %% Domain Name
+  {6,[{172,20,48,1}]},                %% Domain Name Servers
   {51,3600}]}.                        %% Address Lease Time
-
-%%% Red subnet
-{subnet,
- {192,168,10,0},                      %% Network
- {255,255,255,0},                     %% Netmask
- {{192,168,10,5},{192,168,10,10}},    %% Range
- [{1,{255,255,255,0}},                %% Subnet Mask
-  {28,{192,168,10,255}},              %% Broadcast Address
-  {3,[{192,168,10,1}]},               %% Routers
-  {15,"us.nortel.com"},               %% Domain Name
-  {6,[{47,80,19,33}]},                %% Domain Name Servers
-  {51,3600}]}.                        %% Address Lease Time
-
-%%% Yellow subnet
-{subnet,
- {192,168,20,0},                      %% Network
- {255,255,255,0},                     %% Netmask
- {{192,168,20,5},{192,168,20,10}},    %% Range
- [{1,{255,255,255,0}},                %% Subnet Mask
-  {28,{192,168,20,255}},              %% Broadcast Address
-  {3,[{192,168,20,1}]},               %% Routers
-  {15,"us.nortel.com"},               %% Domain Name
-  {6,[{47,80,19,30}]},                %% Domain Name Servers
-  {51,7200}]}.                        %% Address Lease Time
-
-%%% Green subnet
-{subnet,
- {192,168,30,0},                      %% Network
- {255,255,255,0},                     %% Netmask
- {{192,168,30,5},{192,168,30,10}},    %% Range
- [{1,{255,255,255,0}},                %% Subnet Mask
-  {28,{192,168,30,255}},              %% Broadcast Address
-  {3,[{192,168,30,1}]},               %% Routers
-  {15,"us.nortel.com"},               %% Domain Name
-  {6,[{47,80,19,30}]},                %% Domain Name Servers
-  {51,86400}]}.                       %% Address Lease Time

src/dhcp.app.src

@@ -3,6 +3,6 @@
   {vsn, git},
   {modules, [dhcp_app, dhcp_sup, dhcp_server, dhcp_alloc, dhcp_lib]},
   {registered, [dhcp_sup, dhcp_server, dhcp_alloc]},
-  {applications, [kernel, stdlib]},
+  {applications, [kernel, stdlib, lager]},
   {mod, {dhcp_app, []}}
  ]}.

src/dhcp_app.erl

@@ -19,15 +19,16 @@
 %% Function: start(Type, StartArgs) -> {ok, Pid} |
 %%                                     {ok, Pid, State} |
 %%                                     {error, Reason}
-%% Description: This function is called whenever an application 
+%% Description: This function is called whenever an application
 %% is started using application:start/1,2, and should start the processes
 %% of the application. If the application is structured according to the
 %% OTP design principles as a supervision tree, this means starting the
 %% top supervisor of the tree.
 %%--------------------------------------------------------------------
 start(_Type, _StartArgs) ->
+    lager:set_loglevel(lager_console_backend, debug),
     case dhcp_sup:start_link() of
-	{ok, Pid} -> 
+	{ok, Pid} ->
 	    {ok, Pid};
 	Error ->
 	    Error
@@ -37,7 +38,7 @@ start(_Type, _StartArgs) ->
 %% Function: stop(State) -> void()
 %% Description: This function is called whenever an application
 %% has stopped. It is intended to be the opposite of Module:start/2 and
-%% should do any necessary cleaning up. The return value is ignored. 
+%% should do any necessary cleaning up. The return value is ignored.
 %%--------------------------------------------------------------------
 stop(_State) ->
     ok.

src/dhcp_lib.erl

@@ -1,22 +1,23 @@
 %%%-------------------------------------------------------------------
 %%% File    : dhcp_lib.erl
 %%% Author  : Ruslan Babayev <[email protected]>
-%%% Description : 
+%%% Description :
 %%%
 %%% Created : 17 Apr 2006 by Ruslan Babayev <[email protected]>
 %%%-------------------------------------------------------------------
 -module(dhcp_lib).
 
 %% API
 -export([decode/1, encode/1]).
+-export([ip_to_binary/1, eth_to_binary/1]).
 -import(lists, [keymember/3, keysearch/3, keyreplace/4]).
 -include("dhcp.hrl").
 
 %%====================================================================
 %% API
 %%====================================================================
 %%--------------------------------------------------------------------
-%% Function: 
+%% Function:
 %% Description:
 %%--------------------------------------------------------------------
 decode(<<Op, Htype, Hlen, Hops,  Xid:32, Secs:16, Flags:16,