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Subject: Re: [PATCH] bpf: synchronize bpf uapi header with tools
To:     Quentin Monnet <quentin.monnet@netronome.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        David Ahern <dsahern@gmail.com>
References: <20180719125355.26441-1-treeze.taeung@gmail.com>
 <77e00498-74ae-1ee5-8f4b-ad8b3c5f8929@netronome.com>
From:   Taeung Song <treeze.taeung@gmail.com>
Message-ID: <92fb6df6-e631-eba5-a7b3-f6d7173988fb@gmail.com>
Date:   Thu, 19 Jul 2018 23:21:47 +0900
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Hi Quentin,

On 07/19/2018 11:01 PM, Quentin Monnet wrote:
> Hi Taeung,
> 
> 2018-07-19 21:53 UTC+0900 ~ Taeung Song <treeze.taeung@gmail.com>
>> To pick the change in:
>>
>>    4c79579b44b1 ("bpf: Change bpf_fib_lookup to return lookup status")
>>
>> This bpftool build warning occurs:
>>
>>    Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'
>>
>> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
>> Cc: David Ahern <dsahern@gmail.com>
>> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
>> ---
>>   tools/include/uapi/linux/bpf.h | 28 +++++++++++++++++++++++-----
>>   1 file changed, 23 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
>> index 59b19b6a40d7..b7db3261c62d 100644
>> --- a/tools/include/uapi/linux/bpf.h
>> +++ b/tools/include/uapi/linux/bpf.h
>> @@ -1857,7 +1857,8 @@ union bpf_attr {
>>    *		is resolved), the nexthop address is returned in ipv4_dst
>>    *		or ipv6_dst based on family, smac is set to mac address of
>>    *		egress device, dmac is set to nexthop mac address, rt_metric
>> - *		is set to metric from route (IPv4/IPv6 only).
>> + *		is set to metric from route (IPv4/IPv6 only), and ifindex
>> + *		is set to the device index of the nexthop from the FIB lookup.
>>    *
>>    *             *plen* argument is the size of the passed in struct.
>>    *             *flags* argument can be a combination of one or more of the
>> @@ -1873,9 +1874,10 @@ union bpf_attr {
>>    *             *ctx* is either **struct xdp_md** for XDP programs or
>>    *             **struct sk_buff** tc cls_act programs.
>>    *     Return
>> - *             Egress device index on success, 0 if packet needs to continue
>> - *             up the stack for further processing or a negative error in case
>> - *             of failure.
>> + *		* < 0 if any input argument is invalid
>> + *		*   0 on success (packet is forwarded, nexthop neighbor exists)
>> + *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
>> + *		*     packet is not forwarded or needs assist from full stack
>>    *
>>    * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
>>    *	Description
>> @@ -2612,6 +2614,18 @@ struct bpf_raw_tracepoint_args {
>>   #define BPF_FIB_LOOKUP_DIRECT  BIT(0)
>>   #define BPF_FIB_LOOKUP_OUTPUT  BIT(1)
>>   
>> +enum {
>> +	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
>> +	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
>> +	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
>> +	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
>> +	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
>> +	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
>> +	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
>> +	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
>> +	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
>> +};
>> +
>>   struct bpf_fib_lookup {
>>   	/* input:  network family for lookup (AF_INET, AF_INET6)
>>   	 * output: network family of egress nexthop
>> @@ -2625,7 +2639,11 @@ struct bpf_fib_lookup {
>>   
>>   	/* total length of packet from network header - used for MTU check */
>>   	__u16	tot_len;
>> -	__u32	ifindex;  /* L3 device index for lookup */
>> +
>> +	/* input: L3 device index for lookup
>> +	 * output: device index from FIB lookup
>> +	 */
>> +	__u32	ifindex;
>>   
>>   	union {
>>   		/* inputs to lookup */
>>
> 
> This has been updated in the bpf-next tree already, see commit
> 9b8ca3795199 ("tools: bpf: synchronise BPF UAPI header with tools").
> 
> Best regards,
> Quentin
> 

OK ! Thanks.

--
Thanks,
Taeung