[erlang-patches] [PATCH] Fix SCTP multihoming for IPv6
Tomas Abrahamsson
tomas.abrahamsson@REDACTED
Mon Apr 23 23:21:08 CEST 2012
On Mon, Apr 23, 2012 at 16:16 +02:00, Raimo Niskanen wrote:
> Is it so that the sctp_bindx argument 2 declared as (struct sockaddr *)
> is in fact misused to be able to contain IPv6 addresses by packing
> them unaligned?
>
> If so, I would like this fact more visible in the code by defining 'addrs' as:
> char addrs[256 * sizeof(struct inet_address)]
>
> If not, the code looks erroneous (but since there are test cases in the patch
> I would guess the code is right and it is the sctp_bindx call that is weird.
>
> I would have expected argument 2 to be (struct sockaddr_storage *) but on
> my Linux it is not so...
I think I see what you mean, but it seems the 2nd arg
is supposed to be either an array of sockaddr_in or
an array of sockaddr_in6, not the union of them:
addrs is a pointer to an array of one or more socket
addresses. Each address is contained in its appropriate
structure(i.e. struct sockaddr_in or struct
sockaddr_in6).
(quoted from the Linux man page, the Solaris
man page reads similarly)
Looking at it now again, I first thought that addrs should be
either sockaddr_in or sockaddr_in6, not inet_address,
which is the union, but then I re-read the inet_set_address
function, which seems to do just what the man page for
sctp_bindx requires, if I read it correctly.
So I declared the addrs to be of type inet_address to be able
to use the inet_set_address function, and the casting to
(struct sockaddr *) was simply to avoid a compiler warning.
Btw, I did develop the test first, and it failed until
I changed inet_drv.c, so I think it actually works as intended.
Please, let me know if there's anything that I need to do
to get the patch accepted.
BRs
Tomas
> On Fri, Dec 30, 2011 at 09:10:58PM +0100, Tomas Abrahamsson wrote:
>> Setting several ip addresses for an SCTP socket worked for IPv4, but
>> for IPv6 the call to gen_sctp:open/1 failed with badarg.
>> ---
>> erts/emulator/drivers/common/inet_drv.c | 12 +++---
>> lib/kernel/test/gen_sctp_SUITE.erl | 64 ++++++++++++++++++++++++++++++-
>> 2 files changed, 68 insertions(+), 8 deletions(-)
>>
>> diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
>> index eeaa4d2..f712653 100644
>> --- a/erts/emulator/drivers/common/inet_drv.c
>> +++ b/erts/emulator/drivers/common/inet_drv.c
>> @@ -10111,8 +10111,9 @@ static ErlDrvSSizeT packet_inet_ctl(ErlDrvData e, unsigned int cmd, char* buf,
>> /* Construct the list of addresses we bind to. The curr limit is
>> 256 addrs. Buff structure: Flags(1), ListItem,...:
>> */
>> - struct sockaddr addrs[256];
>> + inet_address addrs[256];
>> char* curr;
>> + char* addr_dest;
>> int add_flag, n, rflag;
>>
>> if (!IS_SCTP(desc))
>> @@ -10122,6 +10123,7 @@ static ErlDrvSSizeT packet_inet_ctl(ErlDrvData e, unsigned int cmd, char* buf,
>> add_flag = get_int8(curr);
>> curr++;
>>
>> + addr_dest = (char *)addrs;
>> for(n=0; n < 256 && curr < buf+len; n++)
>> {
>> /* List item format: Port(2), IP(4|16) -- compatible with
>> @@ -10132,16 +10134,14 @@ static ErlDrvSSizeT packet_inet_ctl(ErlDrvData e, unsigned int cmd, char* buf,
>> if (curr == NULL)
>> return ctl_error(EINVAL, rbuf, rsize);
>>
>> - /* Now: we need to squeeze "tmp" into the size of "sockaddr",
>> - which is smaller than "tmp" for IPv6 (extra IN6 info will
>> - be cut off): */
>> - memcpy(addrs + n, &tmp, sizeof(struct sockaddr));
>> + memcpy(addr_dest, &tmp, alen);
>> + addr_dest += alen;
>> }
>> /* Make the real flags: */
>> rflag = add_flag ? SCTP_BINDX_ADD_ADDR : SCTP_BINDX_REM_ADDR;
>>
>> /* Invoke the call: */
>> - if (p_sctp_bindx(desc->s, addrs, n, rflag) < 0)
>> + if (p_sctp_bindx(desc->s, (struct sockaddr *)addrs, n, rflag) < 0)
>> return ctl_error(sock_errno(), rbuf, rsize);
>>
>> desc->state = INET_STATE_BOUND;
>> diff --git a/lib/kernel/test/gen_sctp_SUITE.erl b/lib/kernel/test/gen_sctp_SUITE.erl
>> index 8f490b6..6d6b154 100644
>> --- a/lib/kernel/test/gen_sctp_SUITE.erl
>> +++ b/lib/kernel/test/gen_sctp_SUITE.erl
>> @@ -31,14 +31,16 @@
>> [basic/1,
>> api_open_close/1,api_listen/1,api_connect_init/1,api_opts/1,
>> xfer_min/1,xfer_active/1,def_sndrcvinfo/1,implicit_inet6/1,
>> - basic_stream/1, xfer_stream_min/1, peeloff/1, buffers/1]).
>> + basic_stream/1, xfer_stream_min/1, peeloff/1, buffers/1,
>> + open_multihoming_ipv4_socket/1, open_multihoming_ipv6_socket/1]).
>>
>> suite() -> [{ct_hooks,[ts_install_cth]}].
>>
>> all() ->
>> [basic, api_open_close, api_listen, api_connect_init,
>> api_opts, xfer_min, xfer_active, def_sndrcvinfo, implicit_inet6,
>> - basic_stream, xfer_stream_min, peeloff, buffers].
>> + basic_stream, xfer_stream_min, peeloff, buffers,
>> + open_multihoming_ipv4_socket, open_multihoming_ipv6_socket].
>>
>> groups() ->
>> [].
>> @@ -1329,3 +1331,61 @@ match_unless_solaris(A, B) ->
>> {unix,sunos} -> B;
>> _ -> A = B
>> end.
>> +
>> +open_multihoming_ipv4_socket(doc) ->
>> + "Test opening a multihoming ipv4 socket";
>> +open_multihoming_ipv4_socket(suite) ->
>> + [];
>> +open_multihoming_ipv4_socket(Config) when is_list(Config) ->
>> + ?line Hostname = ok(inet:gethostname()),
>> + ?line HostAddrIPv4 = ok(inet:getaddr(Hostname, inet)),
>> + ?line S = ok(gen_sctp:open(0, [{ip,HostAddrIPv4},{ip,{127,0,0,1}}])),
>> + ?line ok = gen_sctp:listen(S, true),
>> + ?line setup_connection(S, HostAddrIPv4, inet),
>> + ?line ok = gen_sctp:close(S).
>> +
>> +open_multihoming_ipv6_socket(doc) ->
>> + "Test opening a multihoming ipv6 socket";
>> +open_multihoming_ipv6_socket(suite) ->
>> + [];
>> +open_multihoming_ipv6_socket(Config) when is_list(Config) ->
>> + ?line Hostname = ok(inet:gethostname()),
>> + ?line LoopbackIPv6 = {0,0,0,0,0,0,0,1},
>> + ?line
>> + case inet:getaddr(Hostname, inet6) of
>> + {ok,HostAddrIPv6} when HostAddrIPv6 =/= LoopbackIPv6 ->
>> + ?line
>> + case is_good_ipv6_address(HostAddrIPv6) of
>> + true ->
>> + ?line io:format("using ipv6 addresses ~p and ~p~n",
>> + [HostAddrIPv6, LoopbackIPv6]),
>> + ?line S = ok(gen_sctp:open(
>> + 0, [{ip,HostAddrIPv6},
>> + {ip,LoopbackIPv6}, inet6])),
>> + ?line ok = gen_sctp:listen(S, true),
>> + ?line setup_connection(S, HostAddrIPv6, inet6),
>> + ?line ok = gen_sctp:close(S);
>> + false ->
>> + {skip,"Need 2 good IPv6 addresses"}
>> + end;
>> + {ok,HostAddrIPv6} when HostAddrIPv6 =:= LoopbackIPv6 ->
>> + {skip,"Need 2 different IPv6 addresses, found only ::1"};
>> + {error,eafnosupport} ->
>> + {skip,"Can not look up IPv6 address"}
>> + end.
>> +
>> +is_good_ipv6_address({0,0,0,0,0,16#ffff,_,_}) -> false; %% ipv4 mapped
>> +is_good_ipv6_address({16#fe80,_,_,_,_,_,_,_}) -> false; %% link-local
>> +is_good_ipv6_address(_) -> true.
>> +
>> +setup_connection(S1, Addr, IpFamily) ->
>> + ?line P1 = ok(inet:port(S1)),
>> + ?line S2 = ok(gen_sctp:open(0, [IpFamily])),
>> + ?line P2 = ok(inet:port(S2)),
>> + ?line #sctp_assoc_change{state=comm_up} =
>> + ok(gen_sctp:connect(S2, Addr, P1, [])),
>> + ?line case ok(gen_sctp:recv(S1)) of
>> + {Addr,P2,[],#sctp_assoc_change{state=comm_up}} ->
>> + ok
>> + end,
>> + ?line ok = gen_sctp:close(S2).
>> --
>> 1.7.5.4
>>
>> _______________________________________________
>> erlang-patches mailing list
>> erlang-patches@REDACTED
>> http://erlang.org/mailman/listinfo/erlang-patches
>
> --
>
> / Raimo Niskanen, Erlang/OTP, Ericsson AB
More information about the erlang-patches
mailing list