netfilter: nat: remove l4 protocol port rovers

commit 6ed5943f8735e2b778d92ea4d9805c0a1d89bc2b upstream.

This is a leftover from days where single-cpu systems were common:
Store last port used to resolve a clash to use it as a starting point when
the next conflict needs to be resolved.

When we have parallel attempt to connect to same address:port pair,
its likely that both cores end up computing the same "available" port,
as both use same starting port, and newly used ports won't become
visible to other cores until the conntrack gets confirmed later.

One of the cores then has to drop the packet at insertion time because
the chosen new tuple turns out to be in use after all.

Lets simplify this: remove port rover and use a pseudo-random starting
point.

Note that this doesn't make netfilter default to 'fully random' mode;
the 'rover' was only used if NAT could not reuse source port as-is.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/netfilter/nf_nat_l4proto.h b/include/net/netfilter/nf_nat_l4proto.h
index 67835ff8a2d98d4cb8914ee8457f07072962f94b..103ecea6afdb8c82388c76ddd6e6f2e703e9543d 100644 (file)
--- a/include/net/netfilter/nf_nat_l4proto.h
+++ b/include/net/netfilter/nf_nat_l4proto.h
@@ -74,7 +74,7 @@ void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
                                 struct nf_conntrack_tuple *tuple,
                                 const struct nf_nat_range *range,
                                 enum nf_nat_manip_type maniptype,
-                                const struct nf_conn *ct, u16 *rover);
+                                const struct nf_conn *ct);
 
 int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
                                   struct nf_nat_range *range);

diff --git a/net/netfilter/nf_nat_proto_common.c b/net/netfilter/nf_nat_proto_common.c
index 7d7466dbf66338f817bb6698b9dbd637de26d3ed..ac57e47aded22c1dc73b61f78e0d86015edeb4c0 100644 (file)
--- a/net/netfilter/nf_nat_proto_common.c
+++ b/net/netfilter/nf_nat_proto_common.c
@@ -38,8 +38,7 @@ void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
                                 struct nf_conntrack_tuple *tuple,
                                 const struct nf_nat_range *range,
                                 enum nf_nat_manip_type maniptype,
-                                const struct nf_conn *ct,
-                                u16 *rover)
+                                const struct nf_conn *ct)
 {
        unsigned int range_size, min, max, i;
        __be16 *portptr;
@@ -84,15 +83,13 @@ void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
        } else if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) {
                off = prandom_u32();
        } else {
-               off = *rover;
+               off = prandom_u32();
        }
 
        for (i = 0; ; ++off) {
                *portptr = htons(min + off % range_size);
                if (++i != range_size && nf_nat_used_tuple(tuple, ct))
                        continue;
-               if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL))
-                       *rover = off;
                return;
        }
 }

diff --git a/net/netfilter/nf_nat_proto_dccp.c b/net/netfilter/nf_nat_proto_dccp.c
index 269fcd5dc34c495104494ea2890dcc75044d54b6..04c671300a14382cec8e3adc61ce93bcc44f9629 100644 (file)
--- a/net/netfilter/nf_nat_proto_dccp.c
+++ b/net/netfilter/nf_nat_proto_dccp.c
@@ -18,8 +18,6 @@
 #include <net/netfilter/nf_nat_l3proto.h>
 #include <net/netfilter/nf_nat_l4proto.h>
 
-static u_int16_t dccp_port_rover;
-
 static void
 dccp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                  struct nf_conntrack_tuple *tuple,
@@ -27,8 +25,7 @@ dccp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                  enum nf_nat_manip_type maniptype,
                  const struct nf_conn *ct)
 {
-       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
-                                   &dccp_port_rover);
+       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct);
 }
 
 static bool

diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
index c57ee3240b1d5e848077c61f37c72a40ed0d1afd..7329c9b1dc1efb3a1f012a76577d73ae0e140fb0 100644 (file)
--- a/net/netfilter/nf_nat_proto_sctp.c
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -12,8 +12,6 @@
 
 #include <net/netfilter/nf_nat_l4proto.h>
 
-static u_int16_t nf_sctp_port_rover;
-
 static void
 sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                  struct nf_conntrack_tuple *tuple,
@@ -21,8 +19,7 @@ sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                  enum nf_nat_manip_type maniptype,
                  const struct nf_conn *ct)
 {
-       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
-                                   &nf_sctp_port_rover);
+       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct);
 }
 
 static bool

diff --git a/net/netfilter/nf_nat_proto_tcp.c b/net/netfilter/nf_nat_proto_tcp.c
index 4f8820fc514804d775274330f590fe0d1dbab54f..882e79c6df734feab83f47a00ec3f23f9e6c543d 100644 (file)
--- a/net/netfilter/nf_nat_proto_tcp.c
+++ b/net/netfilter/nf_nat_proto_tcp.c
@@ -18,8 +18,6 @@
 #include <net/netfilter/nf_nat_l4proto.h>
 #include <net/netfilter/nf_nat_core.h>
 
-static u16 tcp_port_rover;
-
 static void
 tcp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                 struct nf_conntrack_tuple *tuple,
@@ -27,8 +25,7 @@ tcp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                 enum nf_nat_manip_type maniptype,
                 const struct nf_conn *ct)
 {
-       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
-                                   &tcp_port_rover);
+       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct);
 }
 
 static bool

diff --git a/net/netfilter/nf_nat_proto_udp.c b/net/netfilter/nf_nat_proto_udp.c
index 167ad0dd269c92784147d87aef1f569d543f9307..f48bacd38d9d5021213326feedef38529a550972 100644 (file)
--- a/net/netfilter/nf_nat_proto_udp.c
+++ b/net/netfilter/nf_nat_proto_udp.c
@@ -17,8 +17,6 @@
 #include <net/netfilter/nf_nat_l3proto.h>
 #include <net/netfilter/nf_nat_l4proto.h>
 
-static u16 udp_port_rover;
-
 static void
 udp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                 struct nf_conntrack_tuple *tuple,
@@ -26,8 +24,7 @@ udp_unique_tuple(const struct nf_nat_l3proto *l3proto,
                 enum nf_nat_manip_type maniptype,
                 const struct nf_conn *ct)
 {
-       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
-                                   &udp_port_rover);
+       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct);
 }
 
 static void
@@ -78,8 +75,6 @@ static bool udp_manip_pkt(struct sk_buff *skb,
 }
 
 #ifdef CONFIG_NF_NAT_PROTO_UDPLITE
-static u16 udplite_port_rover;
-
 static bool udplite_manip_pkt(struct sk_buff *skb,
                              const struct nf_nat_l3proto *l3proto,
                              unsigned int iphdroff, unsigned int hdroff,
@@ -103,8 +98,7 @@ udplite_unique_tuple(const struct nf_nat_l3proto *l3proto,
                     enum nf_nat_manip_type maniptype,
                     const struct nf_conn *ct)
 {
-       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
-                                   &udplite_port_rover);
+       nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct);
 }
 
 const struct nf_nat_l4proto nf_nat_l4proto_udplite = {