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Diffstat (limited to 'deps/netlink/src/netlink_codec.erl')
| -rw-r--r-- | deps/netlink/src/netlink_codec.erl | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/deps/netlink/src/netlink_codec.erl b/deps/netlink/src/netlink_codec.erl new file mode 100644 index 0000000..b611232 --- /dev/null +++ b/deps/netlink/src/netlink_codec.erl @@ -0,0 +1,214 @@ +%%% @author tony <tony@rogvall.se> +%%% @copyright (C) 2013, tony +%%% @doc +%%% Encode / Decode of netlink messages +%%% @end +%%% Created : 21 May 2013 by tony <tony@rogvall.se> + +-module(netlink_codec). + +-export([encode_flags/2]). +-export([decode_flags/2]). +-export([encode_tlv/1, encode_tlv_list/1]). +-export([decode_tlv/1, decode_tlv_list/1]). + +-export([decode/2]). +-export([encode/2]). + +-compile(export_all). + +-include("netlink.hrl"). +-include("netl_codec.hrl"). + +-define(ALIGNTO, 4). +-define(ALIGNMASK, (?ALIGNTO-1)). +-define(NLA_ALIGN(N), (((N)+?ALIGNMASK) band (bnot ?ALIGNMASK))). +-define(NLA_PAD(N), ((?ALIGNTO-((N) band ?ALIGNMASK)) band + ?ALIGNMASK)). +%% may need adjustment (NLA_ALIGN(sizeof(struct nlattr))) +-define(NLA_HDRLEN, 4). +%% -define(NLA_PAD(N), (ALIGN(N) - N)). + +%% prove that: +%% ((N+3) band (bnot 3)) - N == (4 - (N band 3)) band 3 +%% + +encode_flags(Flags, Fun) -> + encode_flags(Flags, 0, Fun). + +encode_flags([], Mask, _Fun) -> Mask; +encode_flags([Flag|Flags], Mask, Fun) -> + BitNum = Fun(Flag), + encode_flags(Flags, Mask+(1 bsl BitNum), Fun). + + +decode_flags(Value, Fun) -> + decode_flags(0, Value, Fun). + +decode_flags(_I, 0, _Fun) -> []; +decode_flags(I, Value, Fun) -> + Bit = (1 bsl I), + if Value band Bit =:= Bit -> + [Fun(I) | decode_flags(I+1, Value band (bnot Bit), Fun)]; + true -> + decode_flags(I+1,Value,Fun) + end. + +decode_attr([{Ri,_Endian,Rv}|Ds], Fun) -> + [ Fun(Ri,Rv) | decode_attr(Ds, Fun)]; +decode_attr([], _Fun) -> + []. + +encode_tlv({Type0,Endian,Data}) -> + Payload = if is_list(Data) -> + encode_tlv_list(Data); + is_binary(Data) -> Data + end, + Type = if is_list(Data) -> + Type0 + 16#8000; + Endian =:= big -> + Type0 + 16#4000; + true -> + Type0 + end, + Len = ?NLA_HDRLEN+byte_size(Payload), + Pad = ?NLA_PAD(Len), + <<Len:16/native-unsigned, Type:16/native-unsigned, + Payload/binary, 0:Pad/unit:8>>. + +encode_tlv_list(TLVs) -> + list_to_binary([encode_tlv(TLV) || TLV <- TLVs]). + +next_tlv(<<Len0:16/native-unsigned, _:16, Data/binary>>) -> + Len = Len0 - ?NLA_HDRLEN, + Pad = ?NLA_PAD(Len), + <<_:Len/binary, _:Pad/unit:8, Data1/binary>> = Data, + Data1. + +decode_tlv(<<Len0:16/native-unsigned, Type0:16/native-unsigned, + Rest/binary>>) -> + Len = Len0 - ?NLA_HDRLEN, + <<Payload:Len/binary, _/binary>> = Rest, + Type = Type0 band 16#3fff, + if Type0 band 16#8000 =:= 16#8000 -> + {Type, native, decode_tlv_list(Payload)}; + Type0 band 16#4000 =:= 16#4000 -> + {Type, big, Payload}; + true -> + {Type, native, Payload} + end. + +decode_tlv_list(<<>>) -> + []; +decode_tlv_list(Data) -> + TLV = decode_tlv(Data), + Data1 = next_tlv(Data), + [TLV | decode_tlv_list(Data1)]. + + +decode(Part= + << Len:32/native-integer, + Type:16/native-integer, + Flags:16/native-integer, + Seq:32/native-integer, + Pid:32/native-integer, + Data/binary >>, Acc) -> + if Len >= byte_size(Part) -> + PayloadLen = Len - 16, + << Payload:PayloadLen/bytes, NextPart/binary >> = Data, + Msg = decode_(Type, Flags, Seq, Pid, Payload), + decode(NextPart, [Msg | Acc]); + true -> + decode(<<>>, [{ error, format} | Acc]) + end; +decode(_PadPart, Acc) -> + lists:reverse(Acc). + +decode_(Type,Flags,Seq,Pid,Payload) -> + MsgType = netl_codec:dec_nlmsg_type(Type), + FlagList = case msg_type(MsgType) of + new -> + decode_flags(Flags, fun netl_codec:dec_nlm_new_flags/1); + get -> + decode_flags(Flags, fun netl_codec:dec_nlm_get_flags/1); + _ -> + decode_flags(Flags, fun netl_codec:dec_nlm_flags/1) + end, + MsgPayload = apply(netl_codec, + list_to_atom("dec_"++atom_to_list(MsgType)), + [{native,Payload}]), + H = #nlmsghdr { type=MsgType, flags=FlagList, seq=Seq, pid=Pid }, + #nlmsg { hdr = H, data=MsgPayload }. + +encode(#nlmsghdr { type=MsgType, flags=FlagList, seq=Seq, pid=Pid }, + MsgPayload ) -> + Type = netl_codec:enc_nlmsg_type(MsgType), + Flags = case msg_type(MsgType) of + new -> + encode_flags(FlagList, fun netl_codec:enc_nlm_new_flags/1); + get -> + encode_flags(FlagList, fun netl_codec:enc_nlm_get_flags/1); + _ -> + encode_flags(FlagList, fun netl_codec:enc_nlm_flags/1) + end, + Payload = apply(netl_codec, + list_to_atom("enc_"++atom_to_list(MsgType)), + [{native,MsgPayload}]), + N = byte_size(Payload), + Pad = ?NLA_PAD(N), + Len = 16 + Pad + N, + << Len:32/native-integer, + Type:16/native-integer, + Flags:16/native-integer, + Seq:32/native-integer, + Pid:32/native-integer, + Payload/binary, + 0:Pad/unit:8 >>. + +msg_type(Type) -> + case Type of + noop -> misc; + error -> misc; + done -> misc; + overrun -> misc; + newlink -> new; + dellink -> del; + getlink -> get; + setlink -> set; + newaddr -> new; + deladdr -> del; + getaddr -> get; + newroute -> new; + delroute -> del; + getroute -> get; + newneigh -> new; + delneigh -> del; + getneigh -> get; + newrule -> new; + delrule -> del; + getrule -> get; + newdisc -> new; + delqdisc -> del; + getqdisc -> get; + newtclass -> new; + deltclass -> del; + gettclass -> get; + newtfilter -> new; + deltfilter -> del; + gettfilter -> get; + newaction -> new; + delaction -> del; + getaction -> get; + newprefix -> new; + getmulticast -> get; + getanycast -> get; + newneightbl -> new; + getneightbl -> get; + setneightbl -> set; + newnduseropt -> new; + newaddrlabel -> new; + deladdrlabel -> del; + getaddrlabel -> get; + getdcb -> get; + setdcb -> set + end. |