lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 28 Jul 2016 08:24:20 +0800
From:	Feng Gao <gfree.wind@...il.com>
To:	Tom Herbert <tom@...bertland.com>
Cc:	Gao Feng <fgao@...ai8.com>,
	"David S. Miller" <davem@...emloft.net>,
	philipp@...fish-solutions.com,
	Stephen Hemminger <stephen@...workplumber.org>,
	Pravin B Shelar <pshelar@...ira.com>,
	Alex Duyck <aduyck@...antis.com>,
	Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH 1/1] rps: Inspect PPTP encapsulated by GRE to get flow hash

Thanks Tom, I append some inline comments.

BTW, forgive me reply the email by gmail because the original mail
server doesn't support kernel email format.
I will send the update later.

Best Regards
Feng

On Thu, Jul 28, 2016 at 8:04 AM, Tom Herbert <tom@...bertland.com> 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.

Ok, I get it. Thanks.

>
> > +               */
> > +               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?

Sorry, I fail to find the common definition of PPP frame indeed by
cscope search.

>
> > +                       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?

Ok, I could try to consolidate these codes with the version 0 path.
About the ETH_P_PPP_SES, there are some differences between them.
So I have no idea to 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
> >

Powered by blists - more mailing lists