Nicolas Dichtel wrote:
> Now it's ok in my testbed (without IPsec). There is just a little 
> warning:
>
>   CC      net/sctp/ipv6.o
> net/sctp/ipv6.c: In function ?sctp_v6_get_dst?:
> net/sctp/ipv6.c:250: warning: unused variable ?dst_saddr?
>
>
> Regards,
> Nicolas
>
> Le 07.05.2010 10:47, Weixing.Shi(Stone) a écrit :
>> Vlad Yasevich wrote:
>>> From: Weixing Shi <Weixing.Shi@windriver.com>
>>>
>>> <vlad>
>>> Ok, updated to be a bit more correct.  Only leave the function early 
>>> if the
>>> first lookup succeeds.
>>> </vlad>
>>>
>>> in the below test case, using the source address routing,
>>> sctp can not work.
>>> Node-A
>>> 1)ifconfig eth0 inet6 add 2001:1::1/64
>>> 2)ip -6 rule add from 2001:1::1 table 100 pref 100
>>> 3)ip -6 route add 2001:2::1 dev eth0 table 100
>>> 4)sctp_darn -H 2001:1::1 -P 250 -l &
>>> Node-B
>>> 1)ifconfig eth0 inet6 add 2001:2::1/64
>>> 2)ip -6 rule add from 2001:2::1 table 100 pref 100
>>> 3)ip -6 route add 2001:1::1 dev eth0 table 100
>>> 4)sctp_darn -H 2001:2::1 -P 250 -h 2001:1::1 -p 250 -s
>>>
>>> root cause:
>>> Node-A and Node-B use the source address routing, and
>>> at begining, source address will be NULL,sctp will
>>> search the  routing table by the destination address,
>>> because using the source address routing table, and
>>> the result dst_entry will be NULL.
>>>
>>> solution:
>>> walk through the bind address list to get the source
>>> address and then lookup the routing table again to get
>>> the correct dst_entry.
>>>
>>> Signed-off-by: Weixing Shi <Weixing.Shi@windriver.com>
>>> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
>>> ---
>>>  net/sctp/ipv6.c |  113 
>>> ++++++++++++++++++++++++++++++++++---------------------
>>>  1 files changed, 70 insertions(+), 43 deletions(-)
>>>
>>> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
>>> index 7326891..f75e2f8 100644
>>> --- a/net/sctp/ipv6.c
>>> +++ b/net/sctp/ipv6.c
>>> @@ -77,6 +77,10 @@
>>>  #include <net/sctp/sctp.h>
>>>  
>>>  #include <asm/uaccess.h>
>>> +static void sctp_v6_dst_saddr(union sctp_addr *addr, struct 
>>> dst_entry *dst,
>>> +            __be16 port);
>>> +static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
>>> +          const union sctp_addr *addr2);
>>>  
>>>  /* Event handler for inet6 address addition/deletion events.
>>>   * The sctp_local_addr_list needs to be protocted by a spin lock since
>>> @@ -242,8 +246,12 @@ static struct dst_entry *sctp_v6_get_dst(struct 
>>> sctp_association *asoc,
>>>                       union sctp_addr *daddr,
>>>                       union sctp_addr *saddr)
>>>  {
>>> -    struct dst_entry *dst;
>>> +    struct dst_entry *dst = NULL;
>>>      struct flowi fl;
>>> +    struct sctp_bind_addr *bp;
>>> +    struct sctp_sockaddr_entry *laddr;
>>> +    union sctp_addr dst_saddr;
>>> +    sctp_scope_t scope;
>>>  
>>>      memset(&fl, 0, sizeof(fl));
>>>      ipv6_addr_copy(&fl.fl6_dst, &daddr->v6.sin6_addr);
>>> @@ -259,16 +267,71 @@ static struct dst_entry 
>>> *sctp_v6_get_dst(struct sctp_association *asoc,
>>>      }
>>>  
>>>      dst = ip6_route_output(&init_net, NULL, &fl);
>>> +
>>> +    bp = &asoc->base.bind_addr;
>>> +    scope = sctp_scope(daddr);
>>> +
>>>   
>> if assoc = NULL, will cause kernel crash!
>>>      if (!dst->error) {
>>> +        if (!asoc || saddr)
>>> +            goto out;
>>> +
>>> +        /* Walk through the bind address list and look for a bind
>>> +         * address that matches the source address of the returned 
>>> dst.
>>> +         */
>>> +        sctp_v6_dst_saddr(&dst_saddr, dst, htons(bp->port));
>>> +        rcu_read_lock();
>>> +        list_for_each_entry_rcu(laddr, &bp->address_list, list) {
>>> +            if (!laddr->valid || (laddr->state != SCTP_ADDR_SRC))
>>> +                continue;
>>> +
>>> +            /* Do not compare against v4 addrs */
>>> +            if ((laddr->a.sa.sa_family == AF_INET6) &&
>>> +               (sctp_v6_cmp_addr(&dst_saddr, &laddr->a)))
>>>   
>> we do not concern use source address to find the dest address, so 
>> these lines can ignore!
>>> +                goto out_unlock;
>>> +        }
>>> +        rcu_read_unlock();
>>> +
>>> +        /* None of the bound addresses match the source address of the
>>> +         * dst. So release it.
>>> +         */
>>> +        dst_release(dst);
>>> +        dst = NULL;
>>> +    }
>>> +
>>> +    /* Walk through the bind address list and try to get a dst that
>>> +     * matches a bind address as the source address.
>>> +     */
>>> +    rcu_read_lock();
>>> +    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
>>> +        if (!laddr->valid || (laddr->state != SCTP_ADDR_SRC))
>>> +            continue;
>>> +
>>> +        if ((laddr->a.sa.sa_family == AF_INET6) &&
>>> +            (scope <= sctp_scope(&laddr->a))) {
>>>   
>> here should be consider the most matched ipv6 address for the dest 
>> address, so it should be like :
>> +               list_for_each_entry_rcu(laddr, &bp->address_list, 
>> list) {
>> +                       if (!laddr->valid)
>> +                               continue;
>> +                       if ((laddr->state == SCTP_ADDR_SRC) &&
>> +                          (laddr->a.sa.sa_family == AF_INET6) &&
>> +                          (scope <= sctp_scope(&laddr->a))) {
>> +                               bmatchlen = 
>> sctp_v6_addr_match_len(daddr, &laddr->a);
>> +                               if (!baddr || (matchlen < bmatchlen)) {
>> +                               baddr = &laddr->a;
>> +                               matchlen = bmatchlen;
>> +                               }
>> +                       }
>>
>>> +            ipv6_addr_copy(&fl.fl6_src, &laddr->a.v6.sin6_addr);
>>> +            dst = ip6_route_output(&init_net, NULL, &fl);
>>> +            if (dst->error) {
>>> +                dst_release(dst);
>>> +                dst = NULL;
>>> +            } else
>>> +                break;
>>> +        }
>>> +    }
>>> +
>>> +out_unlock:
>>> +    rcu_read_unlock();
>>> +
>>> +out:
>>> +    if (dst) {
>>>          struct rt6_info *rt;
>>>          rt = (struct rt6_info *)dst;
>>>          SCTP_DEBUG_PRINTK("rt6_dst:%pI6 rt6_src:%pI6\n",
>>>              &rt->rt6i_dst.addr, &rt->rt6i_src.addr);
>>>          return dst;
>>> -    }
>>> -    SCTP_DEBUG_PRINTK("NO ROUTE\n");
>>> -    dst_release(dst);
>>> -    return NULL;
>>> +    } else +        SCTP_DEBUG_PRINTK("NO ROUTE\n");
>>> +
>>> +    return dst;
>>>  }
>>>  
>>>  /* Returns the number of consecutive initial bits that match in the 
>>> 2 ipv6
>>> @@ -289,13 +352,6 @@ static void sctp_v6_get_saddr(struct sctp_sock 
>>> *sk,
>>>                    union sctp_addr *daddr,
>>>                    union sctp_addr *saddr)
>>>  {
>>> -    struct sctp_bind_addr *bp;
>>> -    struct sctp_sockaddr_entry *laddr;
>>> -    sctp_scope_t scope;
>>> -    union sctp_addr *baddr = NULL;
>>> -    __u8 matchlen = 0;
>>> -    __u8 bmatchlen;
>>> -
>>>      SCTP_DEBUG_PRINTK("%s: asoc:%p dst:%p daddr:%pI6 ",
>>>                __func__, asoc, dst, &daddr->v6.sin6_addr);
>>>  
>>> @@ -310,38 +366,9 @@ static void sctp_v6_get_saddr(struct sctp_sock 
>>> *sk,
>>>          return;
>>>      }
>>>  
>>> -    scope = sctp_scope(daddr);
>>> -
>>> -    bp = &asoc->base.bind_addr;
>>> -
>>> -    /* Go through the bind address list and find the best source 
>>> address
>>> -     * that matches the scope of the destination address.
>>> -     */
>>> -    rcu_read_lock();
>>> -    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
>>> -        if (!laddr->valid)
>>> -            continue;
>>> -        if ((laddr->state == SCTP_ADDR_SRC) &&
>>> -            (laddr->a.sa.sa_family == AF_INET6) &&
>>> -            (scope <= sctp_scope(&laddr->a))) {
>>> -            bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
>>> -            if (!baddr || (matchlen < bmatchlen)) {
>>> -                baddr = &laddr->a;
>>> -                matchlen = bmatchlen;
>>> -            }
>>> -        }
>>> -    }
>>> -
>>> -    if (baddr) {
>>> -        memcpy(saddr, baddr, sizeof(union sctp_addr));
>>> -        SCTP_DEBUG_PRINTK("saddr: %pI6\n", &saddr->v6.sin6_addr);
>>> -    } else {
>>> -        printk(KERN_ERR "%s: asoc:%p Could not find a valid source "
>>> -               "address for the dest:%pI6\n",
>>> -               __func__, asoc, &daddr->v6.sin6_addr);
>>> -    }
>>> +    if (dst)
>>> +        sctp_v6_dst_saddr(saddr, dst, 
>>> htons(asoc->base.bind_addr.port));
>>>  
>>> -    rcu_read_unlock();
>>>  }
>>>  
>>>   
>>
>> i open the sctp debug and and find that the using the source address 
>> to find the dst and dst source address does not have correct source 
>> address, it is always 0000:0000:0000:0000:0000:0000:0000:0000, i 
>> think this is maybe an ipv6 route bug, so if modify the code as 
>> yours, sctp can not work!
>>
>>>  /* Make a copy of all potential local addresses. */
>>>   
>> based on the below consideration, i make a new patch for it! it can 
>> work in my environment!
ok! new patch done!

-- 
Weixing.Shi(Stone)
BSP team
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