[NETFILTER]: nf_conntrack: Introduces nf_ct_get_tuplepr and uses it

nf_ct_get_tuple() requires the offset to transport header and that bothers
callers such as icmp[v6] l4proto modules. This introduces new function
to simplify them.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 49 insertions, 59 deletions

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index d4f02eb0c66c..810020ec345d 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -186,6 +186,10 @@ extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 
 extern void nf_conntrack_flush(void);
 
+extern int nf_ct_get_tuplepr(const struct sk_buff *skb,
+                             unsigned int nhoff,
+                             u_int16_t l3num,
+                             struct nf_conntrack_tuple *tuple);
 extern int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
                                 const struct nf_conntrack_tuple *orig);
 
diff --git a/net/ipv4/netfilter/nf_conntrack_proto_icmp.c b/net/ipv4/netfilter/nf_conntrack_proto_icmp.c
index 0fe8fb0466ef..b8b79992797e 100644
--- a/net/ipv4/netfilter/nf_conntrack_proto_icmp.c
+++ b/net/ipv4/netfilter/nf_conntrack_proto_icmp.c
@@ -136,40 +136,22 @@ icmp_error_message(struct sk_buff *skb,
                  unsigned int hooknum)
 {
         struct nf_conntrack_tuple innertuple, origtuple;
-        struct {
-                struct icmphdr icmp;
-                struct iphdr ip;
-        } _in, *inside;
         struct nf_conntrack_l4proto *innerproto;
         struct nf_conntrack_tuple_hash *h;
-        int dataoff;
 
         NF_CT_ASSERT(skb->nfct == NULL);
 
-        /* Not enough header? */
-        inside = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_in), &_in);
-        if (inside == NULL)
-                return -NF_ACCEPT;
-
-        /* Ignore ICMP's containing fragments (shouldn't happen) */
-        if (inside->ip.frag_off & htons(IP_OFFSET)) {
-                pr_debug("icmp_error_message: fragment of proto %u\n",
-                         inside->ip.protocol);
+        /* Are they talking about one of our connections? */
+        if (!nf_ct_get_tuplepr(skb,
+                               skb_network_offset(skb) + ip_hdrlen(skb)
+                                                       + sizeof(struct icmphdr),
+                               PF_INET, &origtuple)) {
+                pr_debug("icmp_error_message: failed to get tuple\n");
                 return -NF_ACCEPT;
         }
 
         /* rcu_read_lock()ed by nf_hook_slow */
-        innerproto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
-
-        dataoff = ip_hdrlen(skb) + sizeof(inside->icmp);
-        /* Are they talking about one of our connections? */
-        if (!nf_ct_get_tuple(skb, dataoff, dataoff + inside->ip.ihl*4, PF_INET,
-                             inside->ip.protocol, &origtuple,
-                             &nf_conntrack_l3proto_ipv4, innerproto)) {
-                pr_debug("icmp_error_message: ! get_tuple p=%u",
-                         inside->ip.protocol);
-                return -NF_ACCEPT;
-        }
+        innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum);
 
         /* Ordinarily, we'd expect the inverted tupleproto, but it's
            been preserved inside the ICMP. */
diff --git a/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c b/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c
index 9defc7e14554..0fca7e8abeb7 100644
--- a/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c
@@ -136,49 +136,23 @@ icmpv6_error_message(struct sk_buff *skb,
 {
         struct nf_conntrack_tuple intuple, origtuple;
         struct nf_conntrack_tuple_hash *h;
-        struct icmp6hdr _hdr, *hp;
-        unsigned int inip6off;
         struct nf_conntrack_l4proto *inproto;
-        u_int8_t inprotonum;
-        unsigned int inprotoff;
 
         NF_CT_ASSERT(skb->nfct == NULL);
 
-        hp = skb_header_pointer(skb, icmp6off, sizeof(_hdr), &_hdr);
-        if (hp == NULL) {
-                pr_debug("icmpv6_error: Can't get ICMPv6 hdr.\n");
-                return -NF_ACCEPT;
-        }
-
-        inip6off = icmp6off + sizeof(_hdr);
-        if (skb_copy_bits(skb, inip6off+offsetof(struct ipv6hdr, nexthdr),
-                          &inprotonum, sizeof(inprotonum)) != 0) {
-                pr_debug("icmpv6_error: Can't get nexthdr in inner IPv6 "
-                         "header.\n");
-                return -NF_ACCEPT;
-        }
-        inprotoff = nf_ct_ipv6_skip_exthdr(skb,
-                                           inip6off + sizeof(struct ipv6hdr),
-                                           &inprotonum,
-                                           skb->len - inip6off
-                                                    - sizeof(struct ipv6hdr));
-
-        if ((inprotoff > skb->len) || (inprotonum == NEXTHDR_FRAGMENT)) {
-                pr_debug("icmpv6_error: Can't get protocol header in ICMPv6 "
-                         "payload.\n");
-                return -NF_ACCEPT;
-        }
-
-        /* rcu_read_lock()ed by nf_hook_slow */
-        inproto = __nf_ct_l4proto_find(PF_INET6, inprotonum);
-
         /* Are they talking about one of our connections? */
-        if (!nf_ct_get_tuple(skb, inip6off, inprotoff, PF_INET6, inprotonum,
-                             &origtuple, &nf_conntrack_l3proto_ipv6, inproto)) {
+        if (!nf_ct_get_tuplepr(skb,
+                               skb_network_offset(skb)
+                                + sizeof(struct ipv6hdr)
+                                + sizeof(struct icmp6hdr),
+                               PF_INET6, &origtuple)) {
                 pr_debug("icmpv6_error: Can't get tuple\n");
                 return -NF_ACCEPT;
         }
 
+        /* rcu_read_lock()ed by nf_hook_slow */
+        inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
+
         /* Ordinarily, we'd expect the inverted tupleproto, but it's
            been preserved inside the ICMP. */
         if (!nf_ct_invert_tuple(&intuple, &origtuple,
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 5b194e3c4e25..8cce814f6bee 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -113,6 +113,36 @@ nf_ct_get_tuple(const struct sk_buff *skb,
 }
 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 
+int nf_ct_get_tuplepr(const struct sk_buff *skb,
+                      unsigned int nhoff,
+                      u_int16_t l3num,
+                      struct nf_conntrack_tuple *tuple)
+{
+        struct nf_conntrack_l3proto *l3proto;
+        struct nf_conntrack_l4proto *l4proto;
+        unsigned int protoff;
+        u_int8_t protonum;
+        int ret;
+
+        rcu_read_lock();
+
+        l3proto = __nf_ct_l3proto_find(l3num);
+        ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
+        if (ret != NF_ACCEPT) {
+                rcu_read_unlock();
+                return 0;
+        }
+
+        l4proto = __nf_ct_l4proto_find(l3num, protonum);
+
+        ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
+                              l3proto, l4proto);
+
+        rcu_read_unlock();
+        return ret;
+}
+EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
+
 int
 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
                    const struct nf_conntrack_tuple *orig,