1 #include <linux/module.h>
2 #include <linux/moduleparam.h>
3 #include <linux/types.h>
4 #include <linux/kernel.h>
5 #include <linux/fs_struct.h>
8 #include <linux/reboot.h>
9 #include <linux/delay.h>
10 #include <linux/proc_fs.h>
11 #include <asm/uaccess.h>
12 #include <linux/sysrq.h>
13 #include <linux/timer.h>
14 #include <linux/time.h>
15 /*#include <linux/lglock.h>*/
16 #include <linux/init.h>
17 #include <linux/idr.h>
18 #include <linux/namei.h>
19 #include <linux/bitops.h>
20 #include <linux/mount.h>
21 #include <linux/dcache.h>
22 #include <linux/spinlock.h>
23 #include <linux/completion.h>
24 #include <linux/sched.h>
25 #include <linux/seq_file.h>
26 #include <linux/kprobes.h>
27 #include <linux/kallsyms.h>
28 #include <linux/nsproxy.h>
30 #include <linux/inetdevice.h>
32 #define VERSION_STR "0.0.1"
35 #error "This code does not support your architecture"
38 MODULE_AUTHOR("Sapan Bhatia <sapanb@cs.princeton.edu>");
39 MODULE_DESCRIPTION("Transparent port forwarding for LXC.");
40 MODULE_LICENSE("GPL");
41 MODULE_VERSION(VERSION_STR);
43 struct proc_dir_entry *proc_entry;
45 static int address_in_root(unsigned int haddr) {
46 struct net_device *dev;
47 struct net *net = &init_net;
49 for_each_netdev(net, dev) {
50 unsigned int ifhaddr = inet_select_addr(dev,0,0);
51 //printk(KERN_CRIT "Checking address: %u",ifhaddr);
52 if (haddr == ifhaddr) return 1;
57 static int inet_bind_entry(struct socket *sock, struct sockaddr *uaddr, int addr_len) {
58 struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
59 unsigned int snum = addr->sin_addr.s_addr;
60 //printk(KERN_CRIT "Checking address %d",snum);
61 if (address_in_root(snum)) {
62 put_net(sock_net(sock->sk));
63 sock_net_set(sock->sk, get_net(&init_net));
64 //printk(KERN_CRIT "Rewiring netns");
70 static struct file *do_last_probe(struct nameidata *nd, struct path *path,
71 const struct open_flags *op, const char *pathname) {
78 static struct jprobe net_probe = {
79 .entry = (kprobe_opcode_t *) inet_bind_entry
83 static void __exit transforward_exit(void)
85 unregister_jprobe(&net_probe);
86 printk("Transforward: Stopped transforward.\n");
91 static int init_probes(void)
94 printk("Transforward: starting transforward version %s.\n",
97 (kprobe_opcode_t *) kallsyms_lookup_name("inet_bind");
98 if (!net_probe.kp.addr) {
99 printk("Couldn't find %s to plant kretprobe\n", "inet_bind");
103 if ((ret = register_jprobe(&net_probe)) <0) {
104 printk("register_jprobe failed, returned %u\n", ret);
111 /* as per http://www.tldp.org/LDP/lkmpg/2.4/html/c577.htm
112 the declaration of write in the file_operations struct reads:
113 ssize_t (*write) (struct file *, const char *, size_t, loff_t *);
115 ssize_t procfile_write(struct file *file, const char *buffer, size_t count, loff_t *data) {
118 if (init_probes()==-1)
119 printk(KERN_CRIT "Could not install procprotect probes. Reload module to retry.");
121 printk(KERN_CRIT "Activated transforward module");
125 static const struct file_operations transforward_fops = {
126 .owner = THIS_MODULE,
127 .write = procfile_write
130 static int __init transforward_init(void)
133 printk("Transforward: starting transforward version %s.\n",
136 proc_entry = proc_create("transforward", 0644, NULL, &transforward_fops);
140 module_init(transforward_init);
141 module_exit(transforward_exit);