patch-2.3.99-pre2 linux/net/ipv4/netfilter/ip_nat_proto_tcp.c
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- Lines: 144
- Date:
Fri Mar 17 10:56:20 2000
- Orig file:
v2.3.99-pre1/linux/net/ipv4/netfilter/ip_nat_proto_tcp.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/ip_nat_proto_tcp.c linux/net/ipv4/netfilter/ip_nat_proto_tcp.c
@@ -0,0 +1,143 @@
+#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>
+
+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 = 0, *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 void
+tcp_manip_pkt(struct iphdr *iph, size_t len,
+ const struct ip_conntrack_manip *manip,
+ enum ip_nat_manip_type maniptype)
+{
+ struct tcphdr *hdr = (struct tcphdr *)((u_int32_t *)iph + iph->ihl);
+ u_int32_t oldip;
+ u_int16_t *portptr;
+
+ if (maniptype == IP_NAT_MANIP_SRC) {
+ /* Get rid of src ip and src pt */
+ oldip = iph->saddr;
+ portptr = &hdr->source;
+ } else {
+ /* Get rid of dst ip and dst pt */
+ oldip = iph->daddr;
+ portptr = &hdr->dest;
+ }
+ hdr->check = ip_nat_cheat_check(~oldip, manip->ip,
+ ip_nat_cheat_check(*portptr ^ 0xFFFF,
+ manip->u.tcp.port,
+ hdr->check));
+ *portptr = manip->u.tcp.port;
+}
+
+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
+= { { NULL, NULL }, "TCP", IPPROTO_TCP,
+ tcp_manip_pkt,
+ tcp_in_range,
+ tcp_unique_tuple,
+ tcp_print,
+ tcp_print_range
+};
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