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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/netfilter/ip_nat_proto_tcp.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/ipv4/netfilter/ip_nat_proto_tcp.c')
-rw-r--r--net/ipv4/netfilter/ip_nat_proto_tcp.c178
1 files changed, 178 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ip_nat_proto_tcp.c b/net/ipv4/netfilter/ip_nat_proto_tcp.c
new file mode 100644
index 00000000000..a91cfceff27
--- /dev/null
+++ b/net/ipv4/netfilter/ip_nat_proto_tcp.c
@@ -0,0 +1,178 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 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/netfilter.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/if.h>
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_nat_protocol.h>
+#include <linux/netfilter_ipv4/ip_nat_core.h>
+
+static int
+tcp_in_range(const struct ip_conntrack_tuple *tuple,
+ enum ip_nat_manip_type maniptype,
+ const union ip_conntrack_manip_proto *min,
+ const union ip_conntrack_manip_proto *max)
+{
+ u_int16_t 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 ip_conntrack_tuple *tuple,
+ const struct ip_nat_range *range,
+ enum ip_nat_manip_type maniptype,
+ const struct ip_conntrack *conntrack)
+{
+ static u_int16_t port, *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 (!ip_nat_used_tuple(tuple, conntrack)) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static int
+tcp_manip_pkt(struct sk_buff **pskb,
+ unsigned int iphdroff,
+ const struct ip_conntrack_tuple *tuple,
+ enum ip_nat_manip_type maniptype)
+{
+ struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff);
+ struct tcphdr *hdr;
+ unsigned int hdroff = iphdroff + iph->ihl*4;
+ u32 oldip, newip;
+ u16 *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_ip_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.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.ip;
+ newport = tuple->dst.u.tcp.port;
+ portptr = &hdr->dest;
+ }
+
+ oldport = *portptr;
+ *portptr = newport;
+
+ if (hdrsize < sizeof(*hdr))
+ return 1;
+
+ hdr->check = ip_nat_cheat_check(~oldip, newip,
+ ip_nat_cheat_check(oldport ^ 0xFFFF,
+ newport,
+ hdr->check));
+ return 1;
+}
+
+static unsigned int
+tcp_print(char *buffer,
+ const struct ip_conntrack_tuple *match,
+ const struct ip_conntrack_tuple *mask)
+{
+ unsigned int len = 0;
+
+ if (mask->src.u.tcp.port)
+ len += sprintf(buffer + len, "srcpt=%u ",
+ ntohs(match->src.u.tcp.port));
+
+
+ if (mask->dst.u.tcp.port)
+ len += sprintf(buffer + len, "dstpt=%u ",
+ ntohs(match->dst.u.tcp.port));
+
+ return len;
+}
+
+static unsigned int
+tcp_print_range(char *buffer, const struct ip_nat_range *range)
+{
+ if (range->min.tcp.port != 0 || range->max.tcp.port != 0xFFFF) {
+ if (range->min.tcp.port == range->max.tcp.port)
+ return sprintf(buffer, "port %u ",
+ ntohs(range->min.tcp.port));
+ else
+ return sprintf(buffer, "ports %u-%u ",
+ ntohs(range->min.tcp.port),
+ ntohs(range->max.tcp.port));
+ }
+ else return 0;
+}
+
+struct ip_nat_protocol ip_nat_protocol_tcp
+= { "TCP", IPPROTO_TCP,
+ tcp_manip_pkt,
+ tcp_in_range,
+ tcp_unique_tuple,
+ tcp_print,
+ tcp_print_range
+};