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Message-ID: <ac82e50b-8827-d13c-f02a-ce75c255721a@redfish-solutions.com>
Date: Wed, 27 Jul 2016 18:46:24 -0600
From: Philp Prindeville <philipp@...fish-solutions.com>
To: Tom Herbert <tom@...bertland.com>,
fgao@...vckh6395k16k5.yundunddos.com
Cc: "David S. Miller" <davem@...emloft.net>,
Stephen Hemminger <stephen@...workplumber.org>,
Pravin B Shelar <pshelar@...ira.com>,
Alex Duyck <aduyck@...antis.com>,
Linux Kernel Network Developers <netdev@...r.kernel.org>,
gfree.wind@...il.com
Subject: Re: [PATCH 1/1] rps: Inspect PPTP encapsulated by GRE to get flow
hash
Inline...
On 07/27/2016 06:04 PM, Tom Herbert wrote:
> On Wed, Jul 27, 2016 at 4:42 PM, <fgao@...ai8.com> wrote:
>> From: Gao Feng <fgao@...ai8.com>
>>
>> The PPTP is encapsulated by GRE header with that GRE_VERSION bits
>> must contain one. But current GRE RPS needs the GRE_VERSION must be
>> zero. So RPS does not work for PPTP traffic.
>>
>> In my test environment, there are four MIPS cores, and all traffic
>> are passed through by PPTP. As a result, only one core is 100% busy
>> while other three cores are very idle. After this patch, the usage
>> of four cores are balanced well.
>>
>> Signed-off-by: Gao Feng <fgao@...ai8.com>
>> ---
>> v1: Initial patch
>>
>> include/uapi/linux/if_tunnel.h | 5 +-
>> net/core/flow_dissector.c | 138 ++++++++++++++++++++++++++---------------
>> 2 files changed, 92 insertions(+), 51 deletions(-)
>>
>> diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
>> index 1046f55..dda4e4b 100644
>> --- a/include/uapi/linux/if_tunnel.h
>> +++ b/include/uapi/linux/if_tunnel.h
>> @@ -24,9 +24,12 @@
>> #define GRE_SEQ __cpu_to_be16(0x1000)
>> #define GRE_STRICT __cpu_to_be16(0x0800)
>> #define GRE_REC __cpu_to_be16(0x0700)
>> -#define GRE_FLAGS __cpu_to_be16(0x00F8)
>> +#define GRE_ACK __cpu_to_be16(0x0080)
>> +#define GRE_FLAGS __cpu_to_be16(0x0078)
>> #define GRE_VERSION __cpu_to_be16(0x0007)
>>
>> +#define GRE_PROTO_PPP __cpu_to_be16(0x880b)
>> +
>> struct ip_tunnel_parm {
>> char name[IFNAMSIZ];
>> int link;
>> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
>> index 61ad43f..d95e060 100644
>> --- a/net/core/flow_dissector.c
>> +++ b/net/core/flow_dissector.c
>> @@ -346,63 +346,101 @@ ip_proto_again:
>> hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
>> if (!hdr)
>> goto out_bad;
>> - /*
>> - * Only look inside GRE if version zero and no
>> - * routing
>> - */
>> - if (hdr->flags & (GRE_VERSION | GRE_ROUTING))
>> - break;
>>
>> - proto = hdr->proto;
>> - nhoff += 4;
>> - if (hdr->flags & GRE_CSUM)
>> + /*
>> + * Only look inside GRE if version zero and no
>> + * routing
> This comment is no longer true, GRE version 1 is being handled.
>
>> + */
>> + if (!(hdr->flags & (GRE_VERSION | GRE_ROUTING))) {
>> + proto = hdr->proto;
>> nhoff += 4;
>> - if (hdr->flags & GRE_KEY) {
>> - const __be32 *keyid;
>> - __be32 _keyid;
>> + if (hdr->flags & GRE_CSUM)
>> + nhoff += 4;
>> + if (hdr->flags & GRE_KEY) {
>> + const __be32 *keyid;
>> + __be32 _keyid;
>> +
>> + keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
>> + data, hlen, &_keyid);
>> +
>> + if (!keyid)
>> + goto out_bad;
>> +
>> + if (dissector_uses_key(flow_dissector,
>> + FLOW_DISSECTOR_KEY_GRE_KEYID)) {
>> + key_keyid = skb_flow_dissector_target(flow_dissector,
>> + FLOW_DISSECTOR_KEY_GRE_KEYID,
>> + target_container);
>> + key_keyid->keyid = *keyid;
>> + }
>> + nhoff += 4;
>> + }
>> + if (hdr->flags & GRE_SEQ)
>> + nhoff += 4;
>> + if (proto == htons(ETH_P_TEB)) {
>> + const struct ethhdr *eth;
>> + struct ethhdr _eth;
>> +
>> + eth = __skb_header_pointer(skb, nhoff,
>> + sizeof(_eth),
>> + data, hlen, &_eth);
>> + if (!eth)
>> + goto out_bad;
>> + proto = eth->h_proto;
>> + nhoff += sizeof(*eth);
>> +
>> + /* Cap headers that we access via pointers at the
>> + * end of the Ethernet header as our maximum alignment
>> + * at that point is only 2 bytes.
>> + */
>> + if (NET_IP_ALIGN)
>> + hlen = nhoff;
>> + }
>>
>> - keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
>> - data, hlen, &_keyid);
>> + key_control->flags |= FLOW_DIS_ENCAPSULATION;
>> + if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
>> + goto out_good;
>>
>> - if (!keyid)
>> + goto again;
>> + } else if (hdr->proto == GRE_PROTO_PPP && (hdr->flags & GRE_VERSION) &&
>> + (hdr->flags & GRE_KEY) &&
>> + !(hdr->flags & (GRE_CSUM | GRE_ROUTING | GRE_STRICT | GRE_REC | GRE_FLAGS))) {
>> + /* It should be the PPTP in GRE
>> + * We have checked the flags according to the
>> + * RFC 2637
>> + */
>> + struct ppp_frame {
>> + /* address & control, just ignore it */
>> + __be16 ignore;
>> + __be16 proto;
>> + } *frame, _frame;
> Isn't there a common definition of a PPP frame?
If there were, it would be in <net/ppp_defs.h> but it's not. It's sort
of implied the macros PPP_ADDRESS(), PPP_CONTROL(), and PPP_PROTOCOL().
Please rewrite the patch to use these.
-Philip
>> + int offset = 0;
>> +
>> + /* Skip GRE header */
>> + offset += 4;
>> + /* Skip payload length and call id */
>> + offset += 4;
>> +
>> + if (hdr->flags & GRE_SEQ)
>> + offset += 4;
>> +
>> + if (hdr->flags & GRE_ACK)
>> + offset += 4;
>> +
>> + frame = skb_header_pointer(skb, nhoff + offset, sizeof(_frame), &_frame);
>> + if (!frame)
>> goto out_bad;
>> -
>> - if (dissector_uses_key(flow_dissector,
>> - FLOW_DISSECTOR_KEY_GRE_KEYID)) {
>> - key_keyid = skb_flow_dissector_target(flow_dissector,
>> - FLOW_DISSECTOR_KEY_GRE_KEYID,
>> - target_container);
>> - key_keyid->keyid = *keyid;
>> + if (frame->proto == __constant_htons(PPP_IP)) {
>> + nhoff += (sizeof(*frame) + offset);
>> + proto = __constant_htons(ETH_P_IP);
>> + goto again;
>> + } else if (frame->proto == __constant_htons(PPP_IPV6)) {
>> + nhoff += (sizeof(*frame) + offset);
>> + proto = __constant_htons(ETH_P_IPV6);
>> + goto again;
> There's a lot of code replication here with the version 0 path. Please
> consolidate these. Also, this looks an awful lot like ETH_P_PPP_SES,
> can this code leverage that code?
>
>> }
>> - nhoff += 4;
>> }
>> - if (hdr->flags & GRE_SEQ)
>> - nhoff += 4;
>> - if (proto == htons(ETH_P_TEB)) {
>> - const struct ethhdr *eth;
>> - struct ethhdr _eth;
>> -
>> - eth = __skb_header_pointer(skb, nhoff,
>> - sizeof(_eth),
>> - data, hlen, &_eth);
>> - if (!eth)
>> - goto out_bad;
>> - proto = eth->h_proto;
>> - nhoff += sizeof(*eth);
>> -
>> - /* Cap headers that we access via pointers at the
>> - * end of the Ethernet header as our maximum alignment
>> - * at that point is only 2 bytes.
>> - */
>> - if (NET_IP_ALIGN)
>> - hlen = nhoff;
>> - }
>> -
>> - key_control->flags |= FLOW_DIS_ENCAPSULATION;
>> - if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
>> - goto out_good;
>> -
>> - goto again;
>> + break;
>> }
>> case NEXTHDR_HOP:
>> case NEXTHDR_ROUTING:
>> --
>> 1.9.1
>>
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