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Message-Id: <20220907154110.8898-8-fw@strlen.de>
Date: Wed, 7 Sep 2022 17:41:09 +0200
From: Florian Westphal <fw@...len.de>
To: <netdev@...r.kernel.org>
Cc: Eric Dumazet <edumazet@...gle.com>,
"David S. Miller" <davem@...emloft.net>,
Paolo Abeni <pabeni@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
<netfilter-devel@...r.kernel.org>, Florian Westphal <fw@...len.de>,
Pablo Neira Ayuso <pablo@...filter.org>
Subject: [PATCH net-next 7/8] netfilter: nat: move repetitive nat port reserve loop to a helper
Almost all nat helpers reserve an expecation port the same way:
Try the port inidcated by the peer, then move to next port if that
port is already in use.
We can squash this into a helper.
Suggested-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Florian Westphal <fw@...len.de>
---
include/net/netfilter/nf_nat_helper.h | 1 +
net/ipv4/netfilter/nf_nat_h323.c | 60 ++-------------------------
net/netfilter/nf_nat_amanda.c | 14 +------
net/netfilter/nf_nat_ftp.c | 17 +-------
net/netfilter/nf_nat_helper.c | 19 +++++++++
net/netfilter/nf_nat_irc.c | 16 +------
net/netfilter/nf_nat_sip.c | 14 +------
7 files changed, 30 insertions(+), 111 deletions(-)
diff --git a/include/net/netfilter/nf_nat_helper.h b/include/net/netfilter/nf_nat_helper.h
index efae84646353..44c421b9be85 100644
--- a/include/net/netfilter/nf_nat_helper.h
+++ b/include/net/netfilter/nf_nat_helper.h
@@ -38,4 +38,5 @@ bool nf_nat_mangle_udp_packet(struct sk_buff *skb, struct nf_conn *ct,
* to port ct->master->saved_proto. */
void nf_nat_follow_master(struct nf_conn *ct, struct nf_conntrack_expect *this);
+u16 nf_nat_exp_find_port(struct nf_conntrack_expect *exp, u16 port);
#endif
diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c
index a334f0dcc2d0..faee20af4856 100644
--- a/net/ipv4/netfilter/nf_nat_h323.c
+++ b/net/ipv4/netfilter/nf_nat_h323.c
@@ -291,20 +291,7 @@ static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
exp->expectfn = nf_nat_follow_master;
exp->dir = !dir;
- /* Try to get same port: if not, try to change it. */
- for (; nated_port != 0; nated_port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(nated_port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- nated_port = 0;
- break;
- }
- }
-
+ nated_port = nf_nat_exp_find_port(exp, nated_port);
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_h323: out of TCP ports\n");
return 0;
@@ -347,20 +334,7 @@ static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
if (info->sig_port[dir] == port)
nated_port = ntohs(info->sig_port[!dir]);
- /* Try to get same port: if not, try to change it. */
- for (; nated_port != 0; nated_port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(nated_port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- nated_port = 0;
- break;
- }
- }
-
+ nated_port = nf_nat_exp_find_port(exp, nated_port);
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_q931: out of TCP ports\n");
return 0;
@@ -439,20 +413,7 @@ static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
if (info->sig_port[dir] == port)
nated_port = ntohs(info->sig_port[!dir]);
- /* Try to get same port: if not, try to change it. */
- for (; nated_port != 0; nated_port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(nated_port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- nated_port = 0;
- break;
- }
- }
-
+ nated_port = nf_nat_exp_find_port(exp, nated_port);
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_ras: out of TCP ports\n");
return 0;
@@ -532,20 +493,7 @@ static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
exp->expectfn = ip_nat_callforwarding_expect;
exp->dir = !dir;
- /* Try to get same port: if not, try to change it. */
- for (nated_port = ntohs(port); nated_port != 0; nated_port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(nated_port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- nated_port = 0;
- break;
- }
- }
-
+ nated_port = nf_nat_exp_find_port(exp, ntohs(port));
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_q931: out of TCP ports\n");
return 0;
diff --git a/net/netfilter/nf_nat_amanda.c b/net/netfilter/nf_nat_amanda.c
index 3bc7e0854efe..98deef6cde69 100644
--- a/net/netfilter/nf_nat_amanda.c
+++ b/net/netfilter/nf_nat_amanda.c
@@ -44,19 +44,7 @@ static unsigned int help(struct sk_buff *skb,
exp->expectfn = nf_nat_follow_master;
/* Try to get same port: if not, try to change it. */
- for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
- int res;
-
- exp->tuple.dst.u.tcp.port = htons(port);
- res = nf_ct_expect_related(exp, 0);
- if (res == 0)
- break;
- else if (res != -EBUSY) {
- port = 0;
- break;
- }
- }
-
+ port = nf_nat_exp_find_port(exp, ntohs(exp->saved_proto.tcp.port));
if (port == 0) {
nf_ct_helper_log(skb, exp->master, "all ports in use");
return NF_DROP;
diff --git a/net/netfilter/nf_nat_ftp.c b/net/netfilter/nf_nat_ftp.c
index aace6768a64e..c92a436d9c48 100644
--- a/net/netfilter/nf_nat_ftp.c
+++ b/net/netfilter/nf_nat_ftp.c
@@ -86,22 +86,9 @@ static unsigned int nf_nat_ftp(struct sk_buff *skb,
* this one. */
exp->expectfn = nf_nat_follow_master;
- /* Try to get same port: if not, try to change it. */
- for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- port = 0;
- break;
- }
- }
-
+ port = nf_nat_exp_find_port(exp, ntohs(exp->saved_proto.tcp.port));
if (port == 0) {
- nf_ct_helper_log(skb, ct, "all ports in use");
+ nf_ct_helper_log(skb, exp->master, "all ports in use");
return NF_DROP;
}
diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c
index a263505455fc..067d6d6f6b7d 100644
--- a/net/netfilter/nf_nat_helper.c
+++ b/net/netfilter/nf_nat_helper.c
@@ -198,3 +198,22 @@ void nf_nat_follow_master(struct nf_conn *ct,
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
}
EXPORT_SYMBOL(nf_nat_follow_master);
+
+u16 nf_nat_exp_find_port(struct nf_conntrack_expect *exp, u16 port)
+{
+ /* Try to get same port: if not, try to change it. */
+ for (; port != 0; port++) {
+ int res;
+
+ exp->tuple.dst.u.tcp.port = htons(port);
+ res = nf_ct_expect_related(exp, 0);
+ if (res == 0)
+ return port;
+
+ if (res != -EBUSY)
+ break;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_nat_exp_find_port);
diff --git a/net/netfilter/nf_nat_irc.c b/net/netfilter/nf_nat_irc.c
index c691ab8d234c..19c4fcc60c50 100644
--- a/net/netfilter/nf_nat_irc.c
+++ b/net/netfilter/nf_nat_irc.c
@@ -48,20 +48,8 @@ static unsigned int help(struct sk_buff *skb,
exp->dir = IP_CT_DIR_REPLY;
exp->expectfn = nf_nat_follow_master;
- /* Try to get same port: if not, try to change it. */
- for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
- int ret;
-
- exp->tuple.dst.u.tcp.port = htons(port);
- ret = nf_ct_expect_related(exp, 0);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- port = 0;
- break;
- }
- }
-
+ port = nf_nat_exp_find_port(exp,
+ ntohs(exp->saved_proto.tcp.port));
if (port == 0) {
nf_ct_helper_log(skb, ct, "all ports in use");
return NF_DROP;
diff --git a/net/netfilter/nf_nat_sip.c b/net/netfilter/nf_nat_sip.c
index f0a735e86851..cf4aeb299bde 100644
--- a/net/netfilter/nf_nat_sip.c
+++ b/net/netfilter/nf_nat_sip.c
@@ -410,19 +410,7 @@ static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff,
exp->dir = !dir;
exp->expectfn = nf_nat_sip_expected;
- for (; port != 0; port++) {
- int ret;
-
- exp->tuple.dst.u.udp.port = htons(port);
- ret = nf_ct_expect_related(exp, NF_CT_EXP_F_SKIP_MASTER);
- if (ret == 0)
- break;
- else if (ret != -EBUSY) {
- port = 0;
- break;
- }
- }
-
+ port = nf_nat_exp_find_port(exp, port);
if (port == 0) {
nf_ct_helper_log(skb, ct, "all ports in use for SIP");
return NF_DROP;
--
2.35.1
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