OSDN Git Service

netfilter: conntrack: remove get_l4proto indirection from l3 protocol trackers
authorFlorian Westphal <fw@strlen.de>
Fri, 29 Jun 2018 05:46:47 +0000 (07:46 +0200)
committerPablo Neira Ayuso <pablo@netfilter.org>
Mon, 16 Jul 2018 15:54:59 +0000 (17:54 +0200)
Handle it in the core instead.

ipv6_skip_exthdr() is built-in even if ipv6 is a module, i.e. this
doesn't create an ipv6 dependency.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
include/net/netfilter/nf_conntrack_l3proto.h
net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
net/netfilter/Makefile
net/netfilter/nf_conntrack_core.c
net/netfilter/nf_conntrack_l3proto_generic.c [deleted file]
net/netfilter/nf_conntrack_proto.c

index 164641c..5f16037 100644 (file)
@@ -24,14 +24,6 @@ struct nf_conntrack_l3proto {
        /* size of tuple nlattr, fills a hole */
        u16 nla_size;
 
-       /*
-        * Called before tracking. 
-        *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
-        *      *protonum: protocol number
-        */
-       int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
-                          unsigned int *dataoff, u_int8_t *protonum);
-
        /* Called when netns wants to use connection tracking */
        int (*net_ns_get)(struct net *);
        void (*net_ns_put)(struct net *);
index e10e38c..9fbf6c7 100644 (file)
@@ -38,35 +38,6 @@ struct conntrack4_net {
        unsigned int users;
 };
 
-static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
-                           unsigned int *dataoff, u_int8_t *protonum)
-{
-       const struct iphdr *iph;
-       struct iphdr _iph;
-
-       iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
-       if (iph == NULL)
-               return -NF_ACCEPT;
-
-       /* Conntrack defragments packets, we might still see fragments
-        * inside ICMP packets though. */
-       if (iph->frag_off & htons(IP_OFFSET))
-               return -NF_ACCEPT;
-
-       *dataoff = nhoff + (iph->ihl << 2);
-       *protonum = iph->protocol;
-
-       /* Check bogus IP headers */
-       if (*dataoff > skb->len) {
-               pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
-                        "nhoff %u, ihl %u, skblen %u\n",
-                        nhoff, iph->ihl << 2, skb->len);
-               return -NF_ACCEPT;
-       }
-
-       return NF_ACCEPT;
-}
-
 static unsigned int ipv4_helper(void *priv,
                                struct sk_buff *skb,
                                const struct nf_hook_state *state)
@@ -297,7 +268,6 @@ static void ipv4_hooks_unregister(struct net *net)
 
 const struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
        .l3proto         = PF_INET,
-       .get_l4proto     = ipv4_get_l4proto,
        .net_ns_get      = ipv4_hooks_register,
        .net_ns_put      = ipv4_hooks_unregister,
        .me              = THIS_MODULE,
index f8051fe..37ab256 100644 (file)
@@ -41,34 +41,6 @@ struct conntrack6_net {
        unsigned int users;
 };
 
-static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
-                           unsigned int *dataoff, u_int8_t *protonum)
-{
-       unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
-       __be16 frag_off;
-       int protoff;
-       u8 nexthdr;
-
-       if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
-                         &nexthdr, sizeof(nexthdr)) != 0) {
-               pr_debug("ip6_conntrack_core: can't get nexthdr\n");
-               return -NF_ACCEPT;
-       }
-       protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
-       /*
-        * (protoff == skb->len) means the packet has not data, just
-        * IPv6 and possibly extensions headers, but it is tracked anyway
-        */
-       if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
-               pr_debug("ip6_conntrack_core: can't find proto in pkt\n");
-               return -NF_ACCEPT;
-       }
-
-       *dataoff = protoff;
-       *protonum = nexthdr;
-       return NF_ACCEPT;
-}
-
 static unsigned int ipv6_helper(void *priv,
                                struct sk_buff *skb,
                                const struct nf_hook_state *state)
@@ -281,7 +253,6 @@ static void ipv6_hooks_unregister(struct net *net)
 
 const struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
        .l3proto                = PF_INET6,
-       .get_l4proto            = ipv6_get_l4proto,
        .net_ns_get             = ipv6_hooks_register,
        .net_ns_put             = ipv6_hooks_unregister,
        .me                     = THIS_MODULE,
index 4444938..f132ea8 100644 (file)
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o utils.o
 
-nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o
+nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMEOUT) += nf_conntrack_timeout.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMESTAMP) += nf_conntrack_timestamp.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o
index 14c0408..0674c6e 100644 (file)
@@ -37,7 +37,6 @@
 #include <linux/rculist_nulls.h>
 
 #include <net/netfilter/nf_conntrack.h>
-#include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_expect.h>
 #include <net/netfilter/nf_conntrack_helper.h>
@@ -55,6 +54,7 @@
 #include <net/netfilter/nf_nat_core.h>
 #include <net/netfilter/nf_nat_helper.h>
 #include <net/netns/hash.h>
+#include <net/ip.h>
 
 #include "nf_internals.h"
 
@@ -273,21 +273,94 @@ nf_ct_get_tuple(const struct sk_buff *skb,
        return l4proto->pkt_to_tuple(skb, dataoff, net, tuple);
 }
 
+static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
+                           u_int8_t *protonum)
+{
+       int dataoff = -1;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK_IPV4)
+       const struct iphdr *iph;
+       struct iphdr _iph;
+
+       iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
+       if (!iph)
+               return -1;
+
+       /* Conntrack defragments packets, we might still see fragments
+        * inside ICMP packets though.
+        */
+       if (iph->frag_off & htons(IP_OFFSET))
+               return -1;
+
+       dataoff = nhoff + (iph->ihl << 2);
+       *protonum = iph->protocol;
+
+       /* Check bogus IP headers */
+       if (dataoff > skb->len) {
+               pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
+                        nhoff, iph->ihl << 2, skb->len);
+               return -1;
+       }
+#endif
+       return dataoff;
+}
+
+static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
+                           u8 *protonum)
+{
+       int protoff = -1;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK_IPV6)
+       unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
+       __be16 frag_off;
+       u8 nexthdr;
+
+       if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
+                         &nexthdr, sizeof(nexthdr)) != 0) {
+               pr_debug("can't get nexthdr\n");
+               return -1;
+       }
+       protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
+       /*
+        * (protoff == skb->len) means the packet has not data, just
+        * IPv6 and possibly extensions headers, but it is tracked anyway
+        */
+       if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
+               pr_debug("can't find proto in pkt\n");
+               return -1;
+       }
+
+       *protonum = nexthdr;
+#endif
+       return protoff;
+}
+
+static int get_l4proto(const struct sk_buff *skb,
+                      unsigned int nhoff, u8 pf, u8 *l4num)
+{
+       switch (pf) {
+       case NFPROTO_IPV4:
+               return ipv4_get_l4proto(skb, nhoff, l4num);
+       case NFPROTO_IPV6:
+               return ipv6_get_l4proto(skb, nhoff, l4num);
+       default:
+               *l4num = 0;
+               break;
+       }
+       return -1;
+}
+
 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
                       u_int16_t l3num,
                       struct net *net, struct nf_conntrack_tuple *tuple)
 {
-       const struct nf_conntrack_l3proto *l3proto;
        const struct nf_conntrack_l4proto *l4proto;
-       unsigned int protoff;
-       u_int8_t protonum;
+       u8 protonum;
+       int protoff;
        int ret;
 
        rcu_read_lock();
 
-       l3proto = __nf_ct_l3proto_find(l3num);
-       ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
-       if (ret != NF_ACCEPT) {
+       protoff = get_l4proto(skb, nhoff, l3num, &protonum);
+       if (protoff <= 0) {
                rcu_read_unlock();
                return false;
        }
@@ -1397,14 +1470,12 @@ unsigned int
 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
                struct sk_buff *skb)
 {
-       const struct nf_conntrack_l3proto *l3proto;
        const struct nf_conntrack_l4proto *l4proto;
        struct nf_conn *ct, *tmpl;
        enum ip_conntrack_info ctinfo;
        unsigned int *timeouts;
-       unsigned int dataoff;
        u_int8_t protonum;
-       int ret;
+       int dataoff, ret;
 
        tmpl = nf_ct_get(skb, &ctinfo);
        if (tmpl || ctinfo == IP_CT_UNTRACKED) {
@@ -1418,14 +1489,12 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
        }
 
        /* rcu_read_lock()ed by nf_hook_thresh */
-       l3proto = __nf_ct_l3proto_find(pf);
-       ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
-                                  &dataoff, &protonum);
-       if (ret <= 0) {
+       dataoff = get_l4proto(skb, skb_network_offset(skb), pf, &protonum);
+       if (dataoff <= 0) {
                pr_debug("not prepared to track yet or error occurred\n");
                NF_CT_STAT_INC_ATOMIC(net, error);
                NF_CT_STAT_INC_ATOMIC(net, invalid);
-               ret = -ret;
+               ret = NF_ACCEPT;
                goto out;
        }
 
@@ -1641,14 +1710,14 @@ static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
 
 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
 {
-       const struct nf_conntrack_l3proto *l3proto;
        const struct nf_conntrack_l4proto *l4proto;
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_tuple tuple;
        enum ip_conntrack_info ctinfo;
        struct nf_nat_hook *nat_hook;
-       unsigned int dataoff, status;
+       unsigned int status;
        struct nf_conn *ct;
+       int dataoff;
        u16 l3num;
        u8 l4num;
 
@@ -1657,10 +1726,9 @@ static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
                return 0;
 
        l3num = nf_ct_l3num(ct);
-       l3proto = nf_ct_l3proto_find_get(l3num);
 
-       if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff,
-                                &l4num) <= 0)
+       dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
+       if (dataoff <= 0)
                return -1;
 
        l4proto = nf_ct_l4proto_find_get(l3num, l4num);
diff --git a/net/netfilter/nf_conntrack_l3proto_generic.c b/net/netfilter/nf_conntrack_l3proto_generic.c
deleted file mode 100644 (file)
index d6a8fe5..0000000
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
- *
- * Based largely upon the original ip_conntrack code which
- * had the following copyright information:
- *
- * (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Author:
- *     Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
- */
-
-#include <linux/types.h>
-#include <linux/ip.h>
-#include <linux/netfilter.h>
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <linux/icmp.h>
-#include <linux/sysctl.h>
-#include <net/ip.h>
-
-#include <linux/netfilter_ipv4.h>
-#include <net/netfilter/nf_conntrack.h>
-#include <net/netfilter/nf_conntrack_l4proto.h>
-#include <net/netfilter/nf_conntrack_l3proto.h>
-#include <net/netfilter/nf_conntrack_core.h>
-#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
-
-static int generic_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
-                              unsigned int *dataoff, u_int8_t *protonum)
-{
-       /* Never track !!! */
-       return -NF_ACCEPT;
-}
-
-
-struct nf_conntrack_l3proto nf_conntrack_l3proto_generic __read_mostly = {
-       .l3proto         = PF_UNSPEC,
-       .get_l4proto     = generic_get_l4proto,
-};
-EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_generic);
index 859cb30..39df72b 100644 (file)
@@ -35,6 +35,11 @@ EXPORT_SYMBOL_GPL(nf_ct_l3protos);
 
 static DEFINE_MUTEX(nf_ct_proto_mutex);
 
+struct nf_conntrack_l3proto nf_conntrack_l3proto_generic __read_mostly = {
+       .l3proto         = PF_UNSPEC,
+};
+EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_generic);
+
 #ifdef CONFIG_SYSCTL
 static int
 nf_ct_register_sysctl(struct net *net,