First checkin of the transforward module for port forwarding

[transforward.git] / transforward.c

diff --git a/transforward.c b/transforward.c
new file mode 100644 (file)
index 0000000..da61cee
--- /dev/null
+++ b/transforward.c
@@ -0,0 +1,105 @@
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs_struct.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>
+#include <linux/proc_fs.h>
+#include <asm/uaccess.h>
+#include <linux/sysrq.h>
+#include <linux/timer.h>
+#include <linux/time.h>
+#include <linux/lglock.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/namei.h>
+#include <linux/bitops.h>
+#include <linux/mount.h>
+#include <linux/dcache.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/kprobes.h>
+#include <linux/kallsyms.h>
+#include <linux/nsproxy.h>
+#include <net/sock.h>
+#include <linux/inetdevice.h>
+
+#define VERSION_STR "0.0.1"
+
+#ifndef CONFIG_X86_64
+#error "This code does not support your architecture"
+#endif
+
+MODULE_AUTHOR("Sapan Bhatia <sapanb@cs.princeton.edu>");
+MODULE_DESCRIPTION("Transparent port forwarding for LXC.");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(VERSION_STR);
+
+static int address_in_root(unsigned int haddr) {
+    printk(KERN_CRIT "In address_in_root: %d",haddr);
+    struct net_device *dev;
+    struct net *net = &init_net;
+
+    for_each_netdev(net, dev) {
+            unsigned int ifhaddr = inet_select_addr(dev,0,0);
+            printk(KERN_CRIT "Checking address: %d",ifhaddr);
+            if (haddr == ifhaddr) return 1;
+    }
+    return 0;
+}
+
+static int inet_bind_entry(struct socket *sock, struct sockaddr *uaddr, int addr_len) {
+    struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
+    unsigned int snum = ntohs(addr->sin_addr.s_addr);
+    if (address_in_root(snum)) {
+        put_net(sock_net(sock->sk));
+        sock_net_set(sock->sk, get_net(&init_net)); 
+        printk(KERN_CRIT "Rewiring netns");
+    }
+    jprobe_return();
+    return 0;
+}
+
+
+static struct jprobe net_probe = {
+       .entry = (kprobe_opcode_t *) inet_bind_entry
+};
+
+
+static void __exit transforward_exit(void)
+{
+       unregister_jprobe(&net_probe);
+       printk("Transforward: Stopped transforward.\n");
+}
+
+
+
+static int __init transforward_init(void)
+{
+    int ret = 0;
+       printk("Transforward: starting transforward version %s.\n",
+              VERSION_STR);
+          net_probe.kp.addr = 
+                  (kprobe_opcode_t *) kallsyms_lookup_name("inet_bind");
+          if (!net_probe.kp.addr) {
+                  printk("Couldn't find %s to plant kretprobe\n", "inet_bind");
+                  return -1;
+          }
+  
+          if ((ret = register_jprobe(&net_probe)) <0) {
+                  printk("register_jprobe failed, returned %d\n", ret);
+                  return -1;
+          }
+          printk("Planted jprobe at %p, handler addr %p\n",
+                 net_probe.kp.addr, net_probe.entry);
+
+        return ret;
+}
+
+module_init(transforward_init);
+module_exit(transforward_exit);