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Message-ID: <1322493738.2292.69.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
Date: Mon, 28 Nov 2011 16:22:18 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: jhs@...atatu.com, jesse@...ira.com, netdev@...r.kernel.org,
dev@...nvswitch.org, chrisw@...hat.com,
herbert@...dor.hengli.com.au, john.r.fastabend@...el.com,
jpettit@...ira.com, Florian Westphal <fw@...len.de>,
Stephen Hemminger <shemminger@...tta.com>,
Dan Siemon <dan@...erfire.com>
Subject: [PATCH net-next 1/4] net: introduce skb_flow_dissect()
We use at least two flow dissectors in network stack, with known
limitations and code duplication.
Introduce skb_flow_dissect() to factorize this, highly inspired from
existing dissector from __skb_get_rxhash()
Note : We extensively use skb_header_pointer(), this permits us to not
touch skb at all.
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
include/net/flow_keys.h | 15 ++++
net/core/Makefile | 2
net/core/flow_dissector.c | 134 ++++++++++++++++++++++++++++++++++++
3 files changed, 150 insertions(+), 1 deletion(-)
diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
new file mode 100644
index 0000000..7a61e21
--- /dev/null
+++ b/include/net/flow_keys.h
@@ -0,0 +1,15 @@
+#ifndef _NET_FLOW_KEYS_H
+#define _NET_FLOW_KEYS_H
+
+struct flow_keys {
+ __be32 src;
+ __be32 dst;
+ union {
+ __be32 ports;
+ __be16 port16[2];
+ };
+ u8 ip_proto;
+};
+
+extern bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow);
+#endif
diff --git a/net/core/Makefile b/net/core/Makefile
index 3606d40..c4ecc86 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -3,7 +3,7 @@
#
obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
- gen_stats.o gen_estimator.o net_namespace.o secure_seq.o
+ gen_stats.o gen_estimator.o net_namespace.o secure_seq.o flow_dissector.o
obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
new file mode 100644
index 0000000..d0e085b
--- /dev/null
+++ b/net/core/flow_dissector.c
@@ -0,0 +1,134 @@
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/if_vlan.h>
+#include <net/ip.h>
+#include <linux/if_tunnel.h>
+#include <linux/if_pppox.h>
+#include <linux/ppp_defs.h>
+#include <net/flow_keys.h>
+
+
+bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
+{
+ int poff, nhoff = skb_network_offset(skb);
+ u8 ip_proto;
+ u16 proto = skb->protocol;
+
+ memset(flow, 0, sizeof(*flow));
+
+again:
+ switch (proto) {
+ case __constant_htons(ETH_P_IP): {
+ const struct iphdr *iph;
+ struct iphdr _iph;
+ip:
+ iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
+ if (!iph)
+ return false;
+
+ if (ip_is_fragment(iph))
+ ip_proto = 0;
+ else
+ ip_proto = iph->protocol;
+ flow->src = iph->saddr;
+ flow->dst = iph->daddr;
+ nhoff += iph->ihl * 4;
+ break;
+ }
+ case __constant_htons(ETH_P_IPV6): {
+ const struct ipv6hdr *iph;
+ struct ipv6hdr _iph;
+ipv6:
+ iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
+ if (!iph)
+ return false;
+
+ ip_proto = iph->nexthdr;
+ flow->src = iph->saddr.s6_addr32[3];
+ flow->dst = iph->daddr.s6_addr32[3];
+ nhoff += sizeof(struct ipv6hdr);
+ break;
+ }
+ case __constant_htons(ETH_P_8021Q): {
+ const struct vlan_hdr *vlan;
+ struct vlan_hdr _vlan;
+
+ vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan);
+ if (!vlan)
+ return false;
+
+ proto = vlan->h_vlan_encapsulated_proto;
+ nhoff += sizeof(*vlan);
+ goto again;
+ }
+ case __constant_htons(ETH_P_PPP_SES): {
+ struct {
+ struct pppoe_hdr hdr;
+ __be16 proto;
+ } *hdr, _hdr;
+ hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
+ if (!hdr)
+ return false;
+ proto = hdr->proto;
+ nhoff += PPPOE_SES_HLEN;
+ switch (proto) {
+ case __constant_htons(PPP_IP):
+ goto ip;
+ case __constant_htons(PPP_IPV6):
+ goto ipv6;
+ default:
+ return false;
+ }
+ }
+ default:
+ return false;
+ }
+
+ switch (ip_proto) {
+ case IPPROTO_GRE: {
+ struct gre_hdr {
+ __be16 flags;
+ __be16 proto;
+ } *hdr, _hdr;
+
+ hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
+ if (!hdr)
+ return false;
+ /*
+ * 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_CSUM)
+ nhoff += 4;
+ if (hdr->flags & GRE_KEY)
+ nhoff += 4;
+ if (hdr->flags & GRE_SEQ)
+ nhoff += 4;
+ goto again;
+ }
+ break;
+ }
+ case IPPROTO_IPIP:
+ goto again;
+ default:
+ break;
+ }
+
+ flow->ip_proto = ip_proto;
+ poff = proto_ports_offset(ip_proto);
+ if (poff >= 0) {
+ __be32 *ports, _ports;
+
+ nhoff += poff;
+ ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports);
+ if (ports)
+ flow->ports = *ports;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(skb_flow_dissect);
--
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