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Date: Wed, 3 Aug 2016 09:15:13 -0700
From: Tom Herbert <tom@...bertland.com>
To: Gao Feng <fgao@...ai8.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Philp Prindeville <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>,
Feng Gao <gfree.wind@...il.com>
Subject: Re: [PATCH v3 1/1] rps: Inspect PPTP encapsulated by GRE to get flow hash
On Wed, Aug 3, 2016 at 7:52 AM, <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>
> ---
> v3: 1) Move struct pptp_gre_header defination into new file pptp.h
> 2) Use sizeof GRE and PPTP type instead of literal value;
> 3) Remove strict flag check for PPTP to robust;
> 4) Consolidate the codes again;
> v2: Update according to Tom and Philp's advice.
> 1) Consolidate the codes with GRE version 0 path;
> 2) Use PPP_PROTOCOL to get ppp protol;
> 3) Set the FLOW_DIS_ENCAPSULATION flag;
> v1: Intial patch
>
> drivers/net/ppp/pptp.c | 36 +----------
> include/net/pptp.h | 40 ++++++++++++
> include/uapi/linux/if_tunnel.h | 7 +-
> net/core/flow_dissector.c | 141 +++++++++++++++++++++++++----------------
> 4 files changed, 134 insertions(+), 90 deletions(-)
> create mode 100644 include/net/pptp.h
>
> diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
> index ae0905e..3e68dbc 100644
> --- a/drivers/net/ppp/pptp.c
> +++ b/drivers/net/ppp/pptp.c
> @@ -37,6 +37,7 @@
> #include <net/icmp.h>
> #include <net/route.h>
> #include <net/gre.h>
> +#include <net/pptp.h>
>
> #include <linux/uaccess.h>
>
> @@ -53,41 +54,6 @@ static struct proto pptp_sk_proto __read_mostly;
> static const struct ppp_channel_ops pptp_chan_ops;
> static const struct proto_ops pptp_ops;
>
> -#define PPP_LCP_ECHOREQ 0x09
> -#define PPP_LCP_ECHOREP 0x0A
> -#define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)
> -
> -#define MISSING_WINDOW 20
> -#define WRAPPED(curseq, lastseq)\
> - ((((curseq) & 0xffffff00) == 0) &&\
> - (((lastseq) & 0xffffff00) == 0xffffff00))
> -
> -#define PPTP_GRE_PROTO 0x880B
> -#define PPTP_GRE_VER 0x1
> -
> -#define PPTP_GRE_FLAG_C 0x80
> -#define PPTP_GRE_FLAG_R 0x40
> -#define PPTP_GRE_FLAG_K 0x20
> -#define PPTP_GRE_FLAG_S 0x10
> -#define PPTP_GRE_FLAG_A 0x80
> -
> -#define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C)
> -#define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R)
> -#define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K)
> -#define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S)
> -#define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A)
> -
> -#define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header))
> -struct pptp_gre_header {
> - u8 flags;
> - u8 ver;
> - __be16 protocol;
> - __be16 payload_len;
> - __be16 call_id;
> - __be32 seq;
> - __be32 ack;
> -} __packed;
> -
> static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
> {
> struct pppox_sock *sock;
> diff --git a/include/net/pptp.h b/include/net/pptp.h
> new file mode 100644
> index 0000000..301d3e2
> --- /dev/null
> +++ b/include/net/pptp.h
> @@ -0,0 +1,40 @@
> +#ifndef _NET_PPTP_H
> +#define _NET_PPTP_H
> +
> +#define PPP_LCP_ECHOREQ 0x09
> +#define PPP_LCP_ECHOREP 0x0A
> +#define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)
> +
> +#define MISSING_WINDOW 20
> +#define WRAPPED(curseq, lastseq)\
> + ((((curseq) & 0xffffff00) == 0) &&\
> + (((lastseq) & 0xffffff00) == 0xffffff00))
> +
> +#define PPTP_GRE_PROTO 0x880B
> +#define PPTP_GRE_VER 0x1
> +
> +#define PPTP_GRE_FLAG_C 0x80
> +#define PPTP_GRE_FLAG_R 0x40
> +#define PPTP_GRE_FLAG_K 0x20
> +#define PPTP_GRE_FLAG_S 0x10
> +#define PPTP_GRE_FLAG_A 0x80
> +
> +#define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C)
> +#define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R)
> +#define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K)
> +#define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S)
> +#define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A)
> +
> +#define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header))
> +struct pptp_gre_header {
> + u8 flags;
> + u8 ver;
> + __be16 protocol;
> + __be16 payload_len;
> + __be16 call_id;
> + __be32 seq;
> + __be32 ack;
> +} __packed;
> +
> +
> +#endif
> diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
> index 1046f55..7d889db 100644
> --- a/include/uapi/linux/if_tunnel.h
> +++ b/include/uapi/linux/if_tunnel.h
> @@ -24,9 +24,14 @@
> #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_VERSION_1 __cpu_to_be16(0x0001)
> +#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..52b7c3c 100644
> --- a/net/core/flow_dissector.c
> +++ b/net/core/flow_dissector.c
> @@ -6,6 +6,8 @@
> #include <linux/if_vlan.h>
> #include <net/ip.h>
> #include <net/ipv6.h>
> +#include <net/gre.h>
> +#include <net/pptp.h>
> #include <linux/igmp.h>
> #include <linux/icmp.h>
> #include <linux/sctp.h>
> @@ -338,71 +340,102 @@ mpls:
> ip_proto_again:
> switch (ip_proto) {
> case IPPROTO_GRE: {
> - struct gre_hdr {
> - __be16 flags;
> - __be16 proto;
> - } *hdr, _hdr;
> + struct gre_base_hdr *hdr, _hdr;
>
> 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)
> - nhoff += 4;
> - if (hdr->flags & GRE_KEY) {
> - const __be32 *keyid;
> - __be32 _keyid;
> + /* Only look inside GRE without routing */
> + if (!(hdr->flags & GRE_ROUTING)) {
> + int offset = 0;
>
> - keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
> - data, hlen, &_keyid);
> + proto = hdr->protocol;
>
> - if (!keyid)
> - goto out_bad;
> + if (hdr->flags & GRE_VERSION) {
> + /* Maybe PPTP in GRE */
> + if (!(proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY) &&
> + (hdr->flags & GRE_VERSION) == GRE_VERSION_1))
> + break;
> + }
>
> - 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;
> + offset += sizeof(struct gre_base_hdr);
> +
> + if (hdr->flags & GRE_CSUM)
> + offset += sizeof(__be32);
> +
> + if (hdr->flags & GRE_KEY) {
> + const __be32 *keyid;
> + __be32 _keyid;
> +
> + keyid = __skb_header_pointer(skb, nhoff + offset, 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;
> + }
> + offset += sizeof(_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;
> - }
>
> - key_control->flags |= FLOW_DIS_ENCAPSULATION;
> - if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
> - goto out_good;
> + if (hdr->flags & GRE_SEQ)
> + offset += sizeof(((struct pptp_gre_header *)0)->seq);
> +
> + if (hdr->flags & GRE_ACK)
> + offset += sizeof(((struct pptp_gre_header *)0)->ack);
> +
> + if (proto == GRE_PROTO_PPP) {
> + u8 _ppp_hdr[PPP_HDRLEN];
> + u8 *ppp_hdr;
> +
> + ppp_hdr = skb_header_pointer(skb, nhoff + offset,
> + sizeof(_ppp_hdr), _ppp_hdr);
> + if (!ppp_hdr)
> + goto out_bad;
> +
> + proto = PPP_PROTOCOL(ppp_hdr);
> + if (proto == PPP_IP)
> + proto = htons(ETH_P_IP);
> + else if (proto == PPP_IPV6)
> + proto = htons(ETH_P_IPV6);
> + else
> + break;
> +
> + offset += PPP_HDRLEN;
> + } else if (proto == htons(ETH_P_TEB)) {
> + const struct ethhdr *eth;
> + struct ethhdr _eth;
> +
> + eth = __skb_header_pointer(skb, nhoff + offset,
> + sizeof(_eth),
> + data, hlen, &_eth);
> + if (!eth)
> + goto out_bad;
> + proto = eth->h_proto;
> + offset += 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 + offset);
> + }
>
> - goto again;
> + nhoff += offset;
> + 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
>
HI Feng,
Please be careful about order of processing GRE options, keyid must be
handled first. GRE_ACK looks like the only new field that needs to be
considered for v1. Also, the keyid in v1 is split into two 16 bit
fields; the first is payload length which is not usable for entropy,
but the second (Call ID) does look useful for that. I would suggest
the IPPROTO_GRE could look something like:
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 61ad43f..736b531 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -342,15 +342,20 @@ ip_proto_again:
__be16 flags;
__be16 proto;
} *hdr, _hdr;
+ u8 gre_ver;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr),
data, hlen, &_hdr);
if (!hdr)
goto out_bad;
+
+ /* Only look inside GRE for versions 0 and 1 */
+ gre_ver = hdr->flags & GRE_VERSION;
+ if (gre_ver > 1)
+ break;
/*
- * Only look inside GRE if version zero and no
- * routing
+ * Only look inside GRE if no routing
*/
- if (hdr->flags & (GRE_VERSION | GRE_ROUTING))
+ if (hdr->flags & GRE_ROUTING)
break;
proto = hdr->proto;
@@ -372,30 +377,62 @@ ip_proto_again:
key_keyid =
skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_GRE_KEYID,
target_container);
- key_keyid->keyid = *keyid;
+ if (gre_ver == 0)
+ key_keyid->keyid = *keyid;
+ else
+ key_keyid->keyid = *keyid &
htonl(0xffff);
}
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;
+ if (gre_ver == 0) {
+ 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;
+ }
+ } else { /* Version 1 */
+ if (hdr->flags & GRE_ACK)
+ offset += 4;
+
+ if (proto == GRE_PROTO_PPP) {
+ u8 _ppp_hdr[PPP_HDRLEN];
+ u8 *ppp_hdr;
+
+ ppp_hdr = skb_header_pointer(skb,
nhoff + offset,
+ sizeof(_ppp_hdr), _ppp_hdr);
+ if (!ppp_hdr)
+ goto out_bad;
+
+ switch (PPP_PROTOCOL(ppp_hdr));
+ case PPP_IP:
+ proto = htons(ETH_P_IP);
+ break;
+ case PPP_IPV6:
+ proto = htons(ETH_P_IPV6);
+ break;
+ default:
+ /* Could probably catch some
more like MPLS */
+ break;
+ }
+
+ offset += PPP_HDRLEN;
+ }
}
key_control->flags |= FLOW_DIS_ENCAPSULATION;
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