[erlang-patches] [PATCH] Fix SCTP multihoming for IPv6
Raimo Niskanen
raimo+erlang-patches@REDACTED
Mon Apr 23 16:16:35 CEST 2012
Hi.
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...
/ Raimo Niskanen, OTP patch reviewer for this patch
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
>
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--
/ Raimo Niskanen, Erlang/OTP, Ericsson AB
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