Vlad Yasevich wrote:
> Bhaskar Dutta wrote:
>> On Thu, Sep 3, 2009 at 7:13 PM, Vlad Yasevich<vladislav.yasevich@xxxxxx> wrote:
>>> Bhaskar Dutta wrote:
>>>> Hi Vlad,
>>>>
>>>> Thanks a lot for the comments. I have incorporated all of them in the
>>>> updated patch below.
>>> One think I forgot to mention the first time, and just thought of it,
>>> is that since you are introducing a new sysctl, it would be very good
>>> to document it in Documents/networking/ip-sysctl.txt.
>>>
>>> There is an SCTP section with all current sctp parameters documented.
>>>
>>> Thanks
>>> -vlad
>>>
>> It is already there. I'd added the new param at the end of the sctp section.
>
> NM. must have looked right past it.... ;)
>
> I'll apply.
Looks like you mail client corrupted the patch such that it doesn't apply.
I'll fix it up this time, but please look at look at Documentation/email-clients
in the kernel tree.
-vlad
>
> Thanks
> -vlad
>
>>>>>> Documentation/networking/ip-sysctl.txt | 10 ++++++++++
>> Thanks,
>> Bhaskar
>>
>>
>>
>>>> Regards,
>>>> Bhaskar
>>>>
>>>>
>>>> Patch Summary:
>>>> =============
>>>> This patch introduces a new sysctl option to make IPv4 Address Scoping
>>>> configurable <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
>>>>
>>>> In networking environments where DNAT rules in iptables prerouting
>>>> chains convert destination IP's to link-local/private IP addresses,
>>>> SCTP connections fail to establish as the INIT chunk is dropped by the
>>>> kernel due to address scope match failure.
>>>> For example to support overlapping IP addresses (same IP address with
>>>> different vlan id) a Layer-5 application listens on link local IP's,
>>>> and there is a DNAT rule that maps the destination IP to a link local
>>>> IP. Such applications never get the SCTP INIT if the address-scoping
>>>> draft is strictly followed.
>>>>
>>>> This sysctl configuration allows SCTP to function in such
>>>> unconventional networking environments.
>>>>
>>>> Sysctl options:
>>>> 0 - Disable IPv4 address scoping draft altogether
>>>> 1 - Enable IPv4 address scoping (default, current behavior)
>>>> 2 - Enable address scoping but allow IPv4 private addresses in init/init-ack
>>>> 3 - Enable address scoping but allow IPv4 link local address in init/init-ack
>>>>
>>>> Patch generated against kernel 2.6.31-rc7.
>>>>
>>>>
>>>> Signed-off-by: Bhaskar Dutta <bhaskar.dutta@xxxxxxxxxxxxxxx>
>>>> ---
>>>> Documentation/networking/ip-sysctl.txt | 10 ++++++++++
>>>> include/net/sctp/constants.h | 7 +++++++
>>>> include/net/sctp/structs.h | 10 ++++++++++
>>>> net/sctp/bind_addr.c | 21 ++++++++++++++++++++-
>>>> net/sctp/protocol.c | 11 ++++++-----
>>>> net/sctp/sysctl.c | 12 ++++++++++++
>>>> 6 files changed, 65 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/Documentation/networking/ip-sysctl.txt
>>>> b/Documentation/networking/ip-sysctl.txt
>>>> index 8be7623..da07602 100644
>>>> --- a/Documentation/networking/ip-sysctl.txt
>>>> +++ b/Documentation/networking/ip-sysctl.txt
>>>> @@ -1282,6 +1282,16 @@ sctp_rmem - vector of 3 INTEGERs: min, default, max
>>>> sctp_wmem - vector of 3 INTEGERs: min, default, max
>>>> See tcp_wmem for a description.
>>>>
>>>> +addr_scope_policy - INTEGER
>>>> + Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00
>>>> +
>>>> + 0 - Disable IPv4 address scoping
>>>> + 1 - Enable IPv4 address scoping
>>>> + 2 - Follow draft but allow IPv4 private addresses
>>>> + 3 - Follow draft but allow IPv4 link local addresses
>>>> +
>>>> + Default: 1
>>>> +
>>>>
>>>> /proc/sys/net/core/*
>>>> dev_weight - INTEGER
>>>> diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
>>>> index b05b055..699e6ae 100644
>>>> --- a/include/net/sctp/constants.h
>>>> +++ b/include/net/sctp/constants.h
>>>> @@ -361,6 +361,13 @@ typedef enum {
>>>> SCTP_SCOPE_UNUSABLE, /* IPv4 unusable addresses */
>>>> } sctp_scope_t;
>>>>
>>>> +typedef enum {
>>>> + SCTP_SCOPE_POLICY_DISABLE, /* Disable IPv4 address scoping */
>>>> + SCTP_SCOPE_POLICY_ENABLE, /* Enable IPv4 address scoping */
>>>> + SCTP_SCOPE_POLICY_PRIVATE, /* Follow draft but allow IPv4 private addresses */
>>>> + SCTP_SCOPE_POLICY_LINK, /* Follow draft but allow IPv4 link local
>>>> addresses */
>>>> +} sctp_scope_policy_t;
>>>> +
>>>> /* Based on IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>,
>>>> * SCTP IPv4 unusable addresses: 0.0.0.0/8, 224.0.0.0/4, 198.18.0.0/24,
>>>> * 192.88.99.0/24.
>>>> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
>>>> index edfcacf..de46ac6 100644
>>>> --- a/include/net/sctp/structs.h
>>>> +++ b/include/net/sctp/structs.h
>>>> @@ -219,6 +219,15 @@ extern struct sctp_globals {
>>>> /* Flag to idicate if SCTP-AUTH is enabled */
>>>> int auth_enable;
>>>>
>>>> + /*
>>>> + * Policy to control SCTP IPv4 address scoping
>>>> + * 0 - Disable IPv4 address scoping
>>>> + * 1 - Enable IPv4 address scoping
>>>> + * 2 - Selectively allow only IPv4 private addresses
>>>> + * 3 - Selectively allow only IPv4 link local address
>>>> + */
>>>> + int ipv4_scope_policy;
>>>> +
>>>> /* Flag to indicate whether computing and verifying checksum
>>>> * is disabled. */
>>>> int checksum_disable;
>>>> @@ -252,6 +261,7 @@ extern struct sctp_globals {
>>>> #define sctp_port_hashtable (sctp_globals.port_hashtable)
>>>> #define sctp_local_addr_list (sctp_globals.local_addr_list)
>>>> #define sctp_local_addr_lock (sctp_globals.addr_list_lock)
>>>> +#define sctp_scope_policy (sctp_globals.ipv4_scope_policy)
>>>> #define sctp_addip_enable (sctp_globals.addip_enable)
>>>> #define sctp_addip_noauth (sctp_globals.addip_noauth_enable)
>>>> #define sctp_prsctp_enable (sctp_globals.prsctp_enable)
>>>> diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
>>>> index 6d5944a..7e33508 100644
>>>> --- a/net/sctp/bind_addr.c
>>>> +++ b/net/sctp/bind_addr.c
>>>> @@ -510,9 +510,28 @@ int sctp_in_scope(const union sctp_addr *addr,
>>>> sctp_scope_t scope)
>>>> * of requested destination address, sender and receiver
>>>> * SHOULD include all of its addresses with level greater
>>>> * than or equal to L.
>>>> + *
>>>> + * Address scoping can be selectively controlled via sysctl
>>>> + * option
>>>> */
>>>> - if (addr_scope <= scope)
>>>> + switch (sctp_scope_policy) {
>>>> + case SCTP_SCOPE_POLICY_DISABLE:
>>>> return 1;
>>>> + case SCTP_SCOPE_POLICY_ENABLE:
>>>> + if (addr_scope <= scope)
>>>> + return 1;
>>>> + break;
>>>> + case SCTP_SCOPE_POLICY_PRIVATE:
>>>> + if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
>>>> + return 1;
>>>> + break;
>>>> + case SCTP_SCOPE_POLICY_LINK:
>>>> + if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
>>>> + return 1;
>>>> + break;
>>>> + default:
>>>> + break;
>>>> + }
>>>>
>>>> return 0;
>>>> }
>>>> diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
>>>> index a76da65..5c65cac 100644
>>>> --- a/net/sctp/protocol.c
>>>> +++ b/net/sctp/protocol.c
>>>> @@ -431,16 +431,14 @@ static int sctp_v4_available(union sctp_addr
>>>> *addr, struct sctp_sock *sp)
>>>> * of requested destination address, sender and receiver
>>>> * SHOULD include all of its addresses with level greater
>>>> * than or equal to L.
>>>> + *
>>>> + * IPv4 scoping can be controlled through sysctl option
>>>> + * net.sctp.addr_scope_policy
>>>> */
>>>> static sctp_scope_t sctp_v4_scope(union sctp_addr *addr)
>>>> {
>>>> sctp_scope_t retval;
>>>>
>>>> - /* Should IPv4 scoping be a sysctl configurable option
>>>> - * so users can turn it off (default on) for certain
>>>> - * unconventional networking environments?
>>>> - */
>>>> -
>>>> /* Check for unusable SCTP addresses. */
>>>> if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
>>>> retval = SCTP_SCOPE_UNUSABLE;
>>>> @@ -1259,6 +1257,9 @@ SCTP_STATIC __init int sctp_init(void)
>>>> /* Disable AUTH by default. */
>>>> sctp_auth_enable = 0;
>>>>
>>>> + /* Set SCOPE policy to enabled */
>>>> + sctp_scope_policy = SCTP_SCOPE_POLICY_ENABLE;
>>>> +
>>>> sctp_sysctl_register();
>>>>
>>>> INIT_LIST_HEAD(&sctp_address_families);
>>>> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
>>>> index 63eabbc..ab7151d 100644
>>>> --- a/net/sctp/sysctl.c
>>>> +++ b/net/sctp/sysctl.c
>>>> @@ -51,6 +51,7 @@ static int timer_max = 86400000; /* ms in one day */
>>>> static int int_max = INT_MAX;
>>>> static int sack_timer_min = 1;
>>>> static int sack_timer_max = 500;
>>>> +static int addr_scope_max = 3; /* check sctp_scope_policy_t in
>>>> include/net/sctp/constants.h for max entries */
>>>>
>>>> extern int sysctl_sctp_mem[3];
>>>> extern int sysctl_sctp_rmem[3];
>>>> @@ -272,6 +273,17 @@ static ctl_table sctp_table[] = {
>>>> .proc_handler = proc_dointvec,
>>>> .strategy = sysctl_intvec
>>>> },
>>>> + {
>>>> + .ctl_name = CTL_UNNUMBERED,
>>>> + .procname = "addr_scope_policy",
>>>> + .data = &sctp_scope_policy,
>>>> + .maxlen = sizeof(int),
>>>> + .mode = 0644,
>>>> + .proc_handler = &proc_dointvec_minmax,
>>>> + .strategy = &sysctl_intvec,
>>>> + .extra1 = &zero,
>>>> + .extra2 = &addr_scope_max,
>>>> + },
>>>> { .ctl_name = 0 }
>>>> };
>>>>
>>>> --
>>>> 1.6.2.6
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