This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / net / ipv4 / netfilter / nf_nat_proto_tcp.c

diff --git a/net/ipv4/netfilter/nf_nat_proto_tcp.c b/net/ipv4/netfilter/nf_nat_proto_tcp.c
new file mode 100644 (file)
index 0000000..f6b99d6
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_proto_tcp.c
@@ -0,0 +1,147 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 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.
+ */
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_nat_protocol.h>
+#include <net/netfilter/nf_nat_core.h>
+
+static int
+tcp_in_range(const struct nf_conntrack_tuple *tuple,
+            enum nf_nat_manip_type maniptype,
+            const union nf_conntrack_man_proto *min,
+            const union nf_conntrack_man_proto *max)
+{
+       __be16 port;
+
+       if (maniptype == IP_NAT_MANIP_SRC)
+               port = tuple->src.u.tcp.port;
+       else
+               port = tuple->dst.u.tcp.port;
+
+       return ntohs(port) >= ntohs(min->tcp.port) &&
+              ntohs(port) <= ntohs(max->tcp.port);
+}
+
+static int
+tcp_unique_tuple(struct nf_conntrack_tuple *tuple,
+                const struct nf_nat_range *range,
+                enum nf_nat_manip_type maniptype,
+                const struct nf_conn *ct)
+{
+       static u_int16_t port;
+       __be16 *portptr;
+       unsigned int range_size, min, i;
+
+       if (maniptype == IP_NAT_MANIP_SRC)
+               portptr = &tuple->src.u.tcp.port;
+       else
+               portptr = &tuple->dst.u.tcp.port;
+
+       /* If no range specified... */
+       if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) {
+               /* If it's dst rewrite, can't change port */
+               if (maniptype == IP_NAT_MANIP_DST)
+                       return 0;
+
+               /* Map privileged onto privileged. */
+               if (ntohs(*portptr) < 1024) {
+                       /* Loose convention: >> 512 is credential passing */
+                       if (ntohs(*portptr)<512) {
+                               min = 1;
+                               range_size = 511 - min + 1;
+                       } else {
+                               min = 600;
+                               range_size = 1023 - min + 1;
+                       }
+               } else {
+                       min = 1024;
+                       range_size = 65535 - 1024 + 1;
+               }
+       } else {
+               min = ntohs(range->min.tcp.port);
+               range_size = ntohs(range->max.tcp.port) - min + 1;
+       }
+
+       for (i = 0; i < range_size; i++, port++) {
+               *portptr = htons(min + port % range_size);
+               if (!nf_nat_used_tuple(tuple, ct))
+                       return 1;
+       }
+       return 0;
+}
+
+static int
+tcp_manip_pkt(struct sk_buff **pskb,
+             unsigned int iphdroff,
+             const struct nf_conntrack_tuple *tuple,
+             enum nf_nat_manip_type maniptype)
+{
+       struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff);
+       struct tcphdr *hdr;
+       unsigned int hdroff = iphdroff + iph->ihl*4;
+       __be32 oldip, newip;
+       __be16 *portptr, newport, oldport;
+       int hdrsize = 8; /* TCP connection tracking guarantees this much */
+
+       /* this could be a inner header returned in icmp packet; in such
+          cases we cannot update the checksum field since it is outside of
+          the 8 bytes of transport layer headers we are guaranteed */
+       if ((*pskb)->len >= hdroff + sizeof(struct tcphdr))
+               hdrsize = sizeof(struct tcphdr);
+
+       if (!skb_make_writable(pskb, hdroff + hdrsize))
+               return 0;
+
+       iph = (struct iphdr *)((*pskb)->data + iphdroff);
+       hdr = (struct tcphdr *)((*pskb)->data + hdroff);
+
+       if (maniptype == IP_NAT_MANIP_SRC) {
+               /* Get rid of src ip and src pt */
+               oldip = iph->saddr;
+               newip = tuple->src.u3.ip;
+               newport = tuple->src.u.tcp.port;
+               portptr = &hdr->source;
+       } else {
+               /* Get rid of dst ip and dst pt */
+               oldip = iph->daddr;
+               newip = tuple->dst.u3.ip;
+               newport = tuple->dst.u.tcp.port;
+               portptr = &hdr->dest;
+       }
+
+       oldport = *portptr;
+       *portptr = newport;
+
+       if (hdrsize < sizeof(*hdr))
+               return 1;
+
+       nf_proto_csum_replace4(&hdr->check, *pskb, oldip, newip, 1);
+       nf_proto_csum_replace2(&hdr->check, *pskb, oldport, newport, 0);
+       return 1;
+}
+
+struct nf_nat_protocol nf_nat_protocol_tcp = {
+       .name                   = "TCP",
+       .protonum               = IPPROTO_TCP,
+       .me                     = THIS_MODULE,
+       .manip_pkt              = tcp_manip_pkt,
+       .in_range               = tcp_in_range,
+       .unique_tuple           = tcp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+       .range_to_nfattr        = nf_nat_port_range_to_nfattr,
+       .nfattr_to_range        = nf_nat_port_nfattr_to_range,
+#endif
+};