[NETFILTER]: ctnetlink: add support for NAT sequence adjustments
The combination of NAT and helpers may produce TCP sequence adjustments.
In failover setups, this information needs to be replicated in order to
achieve a successful recovery of mangled, related connections. This patch is
particularly useful for conntrackd, see:
http://people.netfilter.org/pablo/conntrack-tools/
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index a15971e..d7da167 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -254,6 +254,55 @@
#define ctnetlink_dump_mark(a, b) (0)
#endif
+#ifdef CONFIG_NF_NAT_NEEDED
+static inline int
+dump_nat_seq_adj(struct sk_buff *skb, const struct nf_nat_seq *natseq, int type)
+{
+ __be32 tmp;
+ struct nlattr *nest_parms;
+
+ nest_parms = nla_nest_start(skb, type | NLA_F_NESTED);
+ if (!nest_parms)
+ goto nla_put_failure;
+
+ tmp = htonl(natseq->correction_pos);
+ NLA_PUT(skb, CTA_NAT_SEQ_CORRECTION_POS, sizeof(tmp), &tmp);
+ tmp = htonl(natseq->offset_before);
+ NLA_PUT(skb, CTA_NAT_SEQ_OFFSET_BEFORE, sizeof(tmp), &tmp);
+ tmp = htonl(natseq->offset_after);
+ NLA_PUT(skb, CTA_NAT_SEQ_OFFSET_AFTER, sizeof(tmp), &tmp);
+
+ nla_nest_end(skb, nest_parms);
+
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static inline int
+ctnetlink_dump_nat_seq_adj(struct sk_buff *skb, const struct nf_conn *ct)
+{
+ struct nf_nat_seq *natseq;
+ struct nf_conn_nat *nat = nfct_nat(ct);
+
+ if (!(ct->status & IPS_SEQ_ADJUST) || !nat)
+ return 0;
+
+ natseq = &nat->seq[IP_CT_DIR_ORIGINAL];
+ if (dump_nat_seq_adj(skb, natseq, CTA_NAT_SEQ_ADJ_ORIG) == -1)
+ return -1;
+
+ natseq = &nat->seq[IP_CT_DIR_REPLY];
+ if (dump_nat_seq_adj(skb, natseq, CTA_NAT_SEQ_ADJ_REPLY) == -1)
+ return -1;
+
+ return 0;
+}
+#else
+#define ctnetlink_dump_nat_seq_adj(a, b) (0)
+#endif
+
static inline int
ctnetlink_dump_id(struct sk_buff *skb, const struct nf_conn *ct)
{
@@ -321,7 +370,8 @@
ctnetlink_dump_helpinfo(skb, ct) < 0 ||
ctnetlink_dump_mark(skb, ct) < 0 ||
ctnetlink_dump_id(skb, ct) < 0 ||
- ctnetlink_dump_use(skb, ct) < 0)
+ ctnetlink_dump_use(skb, ct) < 0 ||
+ ctnetlink_dump_nat_seq_adj(skb, ct) < 0)
goto nla_put_failure;
nlh->nlmsg_len = skb_tail_pointer(skb) - b;
@@ -424,6 +474,10 @@
(ctnetlink_dump_counters(skb, ct, IP_CT_DIR_ORIGINAL) < 0 ||
ctnetlink_dump_counters(skb, ct, IP_CT_DIR_REPLY) < 0))
goto nla_put_failure;
+
+ if (events & IPCT_NATSEQADJ &&
+ ctnetlink_dump_nat_seq_adj(skb, ct) < 0)
+ goto nla_put_failure;
}
nlh->nlmsg_len = skb->tail - b;
@@ -935,6 +989,66 @@
return err;
}
+#ifdef CONFIG_NF_NAT_NEEDED
+static inline int
+change_nat_seq_adj(struct nf_nat_seq *natseq, struct nlattr *attr)
+{
+ struct nlattr *cda[CTA_NAT_SEQ_MAX+1];
+
+ nla_parse_nested(cda, CTA_NAT_SEQ_MAX, attr, NULL);
+
+ if (!cda[CTA_NAT_SEQ_CORRECTION_POS])
+ return -EINVAL;
+
+ natseq->correction_pos =
+ ntohl(*(__be32 *)nla_data(cda[CTA_NAT_SEQ_CORRECTION_POS]));
+
+ if (!cda[CTA_NAT_SEQ_OFFSET_BEFORE])
+ return -EINVAL;
+
+ natseq->offset_before =
+ ntohl(*(__be32 *)nla_data(cda[CTA_NAT_SEQ_OFFSET_BEFORE]));
+
+ if (!cda[CTA_NAT_SEQ_OFFSET_AFTER])
+ return -EINVAL;
+
+ natseq->offset_after =
+ ntohl(*(__be32 *)nla_data(cda[CTA_NAT_SEQ_OFFSET_AFTER]));
+
+ return 0;
+}
+
+static int
+ctnetlink_change_nat_seq_adj(struct nf_conn *ct, struct nlattr *cda[])
+{
+ int ret = 0;
+ struct nf_conn_nat *nat = nfct_nat(ct);
+
+ if (!nat)
+ return 0;
+
+ if (cda[CTA_NAT_SEQ_ADJ_ORIG]) {
+ ret = change_nat_seq_adj(&nat->seq[IP_CT_DIR_ORIGINAL],
+ cda[CTA_NAT_SEQ_ADJ_ORIG]);
+ if (ret < 0)
+ return ret;
+
+ ct->status |= IPS_SEQ_ADJUST;
+ }
+
+ if (cda[CTA_NAT_SEQ_ADJ_REPLY]) {
+ ret = change_nat_seq_adj(&nat->seq[IP_CT_DIR_REPLY],
+ cda[CTA_NAT_SEQ_ADJ_REPLY]);
+ if (ret < 0)
+ return ret;
+
+ ct->status |= IPS_SEQ_ADJUST;
+ }
+
+ return 0;
+}
+#endif
+
static int
ctnetlink_change_conntrack(struct nf_conn *ct, struct nlattr *cda[])
{
@@ -969,6 +1083,14 @@
ct->mark = ntohl(*(__be32 *)nla_data(cda[CTA_MARK]));
#endif
+#ifdef CONFIG_NF_NAT_NEEDED
+ if (cda[CTA_NAT_SEQ_ADJ_ORIG] || cda[CTA_NAT_SEQ_ADJ_REPLY]) {
+ err = ctnetlink_change_nat_seq_adj(ct, cda);
+ if (err < 0)
+ return err;
+ }
+#endif
+
return 0;
}