patch-2.1.124 linux/Documentation/networking/ip_masq/ip_masq-API-ex.c

• Lines: 78
• Date: Sun Oct 4 10:21:45 1998
• Orig file: v2.1.123/linux/Documentation/networking/ip_masq/ip_masq-API-ex.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.123/linux/Documentation/networking/ip_masq/ip_masq-API-ex.c linux/Documentation/networking/ip_masq/ip_masq-API-ex.c
@@ -0,0 +1,77 @@
+/*
+   There is only 1 optname (see setsockopt(2)), IP_FW_MASQ_CTL that
+   must be used.
+   Funcionality depends on your kernel CONFIG options, here is
+   an example you can use to create an ``incoming'' tunnel:
+
+   See "user.c" module under ipmasqadm tree for a generic example
+ */
+#undef __KERNEL__	/* Makefile lazyness ;) */
+#include <stdio.h>
+#include <stdlib.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+
+#include <asm/types.h>          /* For __uXX types */
+#include <net/if.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/udp.h>
+#include <netinet/tcp.h>
+#include <linux/ip_fw.h>        /* For IP_FW_MASQ_CTL */
+#include <linux/ip_masq.h>      /* For specific masq defs */
+
+
+int create_listening_masq(struct ip_masq_ctl *masq, int proto, u_int32_t src_addr, u_int16_t src_port, u_int32_t dst_addr)
+{
+	int sockfd;
+
+	sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
+
+	if (sockfd<0) {
+		perror("socket(RAW)");
+		return -1;
+	}
+
+	memset (masq, 0, sizeof (*masq));
+
+	/*
+	 *	Want user tunnel control
+	 */
+	masq->m_target = IP_MASQ_TARGET_USER;
+
+	/*
+	 *	Want to insert new
+	 */
+	masq->m_cmd    = IP_MASQ_CMD_INSERT;
+
+	masq->u.user.protocol	= proto;
+	masq->u.user.saddr	= src_addr;
+	masq->u.user.sport	= src_port;
+	masq->u.user.rt_daddr	= inet_addr("192.168.21.239"); 
+
+	if (setsockopt(sockfd, IPPROTO_IP, 
+				IP_FW_MASQ_CTL, (char *)masq, sizeof(*masq)))    {
+		perror("setsockopt()");
+		return -1;
+	}
+	/* masq struct now contains tunnel details */
+	fprintf(stderr, "PROTO=%d SRC=0x%X:%x - MASQ=0x%X:%x - DST=0x%X:%x\n",
+			masq->u.user.protocol,
+			ntohl(masq->u.user.saddr), ntohs(masq->u.user.sport),
+			ntohl(masq->u.user.maddr), ntohs(masq->u.user.mport),
+			ntohl(masq->u.user.daddr), ntohs(masq->u.user.dport));
+	return 0;
+}
+
+int main(void) {
+	struct ip_masq_ctl masq_buf;
+
+	return create_listening_masq(&masq_buf,
+			IPPROTO_TCP, 
+			inet_addr("192.168.1.4"), 
+			htons(23),
+			inet_addr("192.168.21.3"));
+}
+