196 lines
4.4 KiB
Diff
196 lines
4.4 KiB
Diff
From: Eric Dumazet <eric.dumazet@gmail.com>
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Date: Mon, 28 Nov 2011 05:22:18 +0000
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Subject: [PATCH 1/3] net: introduce skb_flow_dissect()
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commit 0744dd00c1b1be99a25b62b1b48df440e82e57e0 upstream.
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We use at least two flow dissectors in network stack, with known
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limitations and code duplication.
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Introduce skb_flow_dissect() to factorize this, highly inspired from
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existing dissector from __skb_get_rxhash()
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Note : We extensively use skb_header_pointer(), this permits us to not
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touch skb at all.
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Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
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new file mode 100644
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index 0000000..e4cb285
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--- /dev/null
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+++ b/include/net/flow_keys.h
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@@ -0,0 +1,15 @@
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+#ifndef _NET_FLOW_KEYS_H
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+#define _NET_FLOW_KEYS_H
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+
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+struct flow_keys {
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+ __be32 src;
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+ __be32 dst;
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+ union {
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+ __be32 ports;
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+ __be16 port16[2];
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+ };
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+ u8 ip_proto;
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+};
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+
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+extern bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow);
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+#endif
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diff --git a/net/core/Makefile b/net/core/Makefile
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index 3606d40..c4ecc86 100644
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--- a/net/core/Makefile
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+++ b/net/core/Makefile
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@@ -3,7 +3,7 @@
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#
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obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
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- gen_stats.o gen_estimator.o net_namespace.o secure_seq.o
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+ gen_stats.o gen_estimator.o net_namespace.o secure_seq.o flow_dissector.o
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obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
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diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
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new file mode 100644
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index 0000000..f0516d9
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--- /dev/null
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+++ b/net/core/flow_dissector.c
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@@ -0,0 +1,134 @@
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+#include <linux/skbuff.h>
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+#include <linux/ip.h>
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+#include <linux/ipv6.h>
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+#include <linux/if_vlan.h>
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+#include <net/ip.h>
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+#include <linux/if_tunnel.h>
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+#include <linux/if_pppox.h>
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+#include <linux/ppp_defs.h>
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+#include <net/flow_keys.h>
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+
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+
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+bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
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+{
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+ int poff, nhoff = skb_network_offset(skb);
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+ u8 ip_proto;
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+ __be16 proto = skb->protocol;
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+
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+ memset(flow, 0, sizeof(*flow));
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+
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+again:
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+ switch (proto) {
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+ case __constant_htons(ETH_P_IP): {
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+ const struct iphdr *iph;
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+ struct iphdr _iph;
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+ip:
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+ iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
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+ if (!iph)
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+ return false;
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+
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+ if (ip_is_fragment(iph))
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+ ip_proto = 0;
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+ else
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+ ip_proto = iph->protocol;
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+ flow->src = iph->saddr;
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+ flow->dst = iph->daddr;
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+ nhoff += iph->ihl * 4;
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+ break;
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+ }
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+ case __constant_htons(ETH_P_IPV6): {
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+ const struct ipv6hdr *iph;
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+ struct ipv6hdr _iph;
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+ipv6:
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+ iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
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+ if (!iph)
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+ return false;
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+
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+ ip_proto = iph->nexthdr;
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+ flow->src = iph->saddr.s6_addr32[3];
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+ flow->dst = iph->daddr.s6_addr32[3];
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+ nhoff += sizeof(struct ipv6hdr);
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+ break;
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+ }
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+ case __constant_htons(ETH_P_8021Q): {
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+ const struct vlan_hdr *vlan;
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+ struct vlan_hdr _vlan;
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+
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+ vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan);
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+ if (!vlan)
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+ return false;
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+
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+ proto = vlan->h_vlan_encapsulated_proto;
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+ nhoff += sizeof(*vlan);
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+ goto again;
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+ }
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+ case __constant_htons(ETH_P_PPP_SES): {
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+ struct {
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+ struct pppoe_hdr hdr;
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+ __be16 proto;
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+ } *hdr, _hdr;
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+ hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
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+ if (!hdr)
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+ return false;
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+ proto = hdr->proto;
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+ nhoff += PPPOE_SES_HLEN;
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+ switch (proto) {
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+ case __constant_htons(PPP_IP):
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+ goto ip;
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+ case __constant_htons(PPP_IPV6):
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+ goto ipv6;
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+ default:
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+ return false;
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+ }
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+ }
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+ default:
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+ return false;
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+ }
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+
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+ switch (ip_proto) {
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+ case IPPROTO_GRE: {
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+ struct gre_hdr {
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+ __be16 flags;
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+ __be16 proto;
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+ } *hdr, _hdr;
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+
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+ hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
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+ if (!hdr)
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+ return false;
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+ /*
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+ * Only look inside GRE if version zero and no
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+ * routing
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+ */
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+ if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
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+ proto = hdr->proto;
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+ nhoff += 4;
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+ if (hdr->flags & GRE_CSUM)
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+ nhoff += 4;
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+ if (hdr->flags & GRE_KEY)
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+ nhoff += 4;
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+ if (hdr->flags & GRE_SEQ)
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+ nhoff += 4;
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+ goto again;
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+ }
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+ break;
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+ }
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+ case IPPROTO_IPIP:
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+ goto again;
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+ default:
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+ break;
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+ }
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+
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+ flow->ip_proto = ip_proto;
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+ poff = proto_ports_offset(ip_proto);
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+ if (poff >= 0) {
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+ __be32 *ports, _ports;
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+
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+ nhoff += poff;
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+ ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports);
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+ if (ports)
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+ flow->ports = *ports;
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+ }
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+
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+ return true;
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+}
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+EXPORT_SYMBOL(skb_flow_dissect);
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--
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1.7.10
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