[PATCH 1/1] rps: Inspect PPTP encapsulated by GRE to get flow hash
From: <hidden>
Date: 2016-07-27 23:50:57
From: Gao Feng <redacted> 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 <redacted> --- 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 + */ + 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; + 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; } - 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:
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1.9.1