dv.c
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上传日期:2013-02-24
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文件大小:12k
- /*
- * INET An implementation of the TCP/IP protocol suite for the LINUX
- * operating system. INET is implemented using the BSD Socket
- * interface as the means of communication with the user level.
- *
- * Generic frame diversion
- *
- * Version: @(#)eth.c 0.41 09/09/2000
- *
- * Authors:
- * Benoit LOCHER: initial integration within the kernel with support for ethernet
- * Dave Miller: improvement on the code (correctness, performance and source files)
- *
- */
- #include <linux/types.h>
- #include <linux/kernel.h>
- #include <linux/sched.h>
- #include <linux/string.h>
- #include <linux/mm.h>
- #include <linux/socket.h>
- #include <linux/in.h>
- #include <linux/inet.h>
- #include <linux/ip.h>
- #include <linux/udp.h>
- #include <linux/netdevice.h>
- #include <linux/etherdevice.h>
- #include <linux/skbuff.h>
- #include <linux/errno.h>
- #include <linux/init.h>
- #include <net/dst.h>
- #include <net/arp.h>
- #include <net/sock.h>
- #include <net/ipv6.h>
- #include <net/ip.h>
- #include <asm/uaccess.h>
- #include <asm/system.h>
- #include <asm/checksum.h>
- #include <linux/divert.h>
- #include <linux/sockios.h>
- const char sysctl_divert_version[32]="0.46"; /* Current version */
- int __init dv_init(void)
- {
- printk(KERN_INFO "NET4: Frame Diverter %sn", sysctl_divert_version);
- return 0;
- }
- /*
- * Allocate a divert_blk for a device. This must be an ethernet nic.
- */
- int alloc_divert_blk(struct net_device *dev)
- {
- int alloc_size = (sizeof(struct divert_blk) + 3) & ~3;
- if (dev->type == ARPHRD_ETHER) {
- printk(KERN_DEBUG "divert: allocating divert_blk for %sn",
- dev->name);
- dev->divert = (struct divert_blk *)
- kmalloc(alloc_size, GFP_KERNEL);
- if (dev->divert == NULL) {
- printk(KERN_DEBUG "divert: unable to allocate divert_blk for %sn",
- dev->name);
- return -ENOMEM;
- } else {
- memset(dev->divert, 0, sizeof(struct divert_blk));
- }
- dev_hold(dev);
- } else {
- printk(KERN_DEBUG "divert: not allocating divert_blk for non-ethernet device %sn",
- dev->name);
- dev->divert = NULL;
- }
- return 0;
- }
- /*
- * Free a divert_blk allocated by the above function, if it was
- * allocated on that device.
- */
- void free_divert_blk(struct net_device *dev)
- {
- if (dev->divert) {
- kfree(dev->divert);
- dev->divert=NULL;
- dev_put(dev);
- printk(KERN_DEBUG "divert: freeing divert_blk for %sn",
- dev->name);
- } else {
- printk(KERN_DEBUG "divert: no divert_blk to free, %s not ethernetn",
- dev->name);
- }
- }
- /*
- * Adds a tcp/udp (source or dest) port to an array
- */
- int add_port(u16 ports[], u16 port)
- {
- int i;
- if (port == 0)
- return -EINVAL;
- /* Storing directly in network format for performance,
- * thanks Dave :)
- */
- port = htons(port);
- for (i = 0; i < MAX_DIVERT_PORTS; i++) {
- if (ports[i] == port)
- return -EALREADY;
- }
-
- for (i = 0; i < MAX_DIVERT_PORTS; i++) {
- if (ports[i] == 0) {
- ports[i] = port;
- return 0;
- }
- }
- return -ENOBUFS;
- }
- /*
- * Removes a port from an array tcp/udp (source or dest)
- */
- int remove_port(u16 ports[], u16 port)
- {
- int i;
- if (port == 0)
- return -EINVAL;
-
- /* Storing directly in network format for performance,
- * thanks Dave !
- */
- port = htons(port);
- for (i = 0; i < MAX_DIVERT_PORTS; i++) {
- if (ports[i] == port) {
- ports[i] = 0;
- return 0;
- }
- }
- return -EINVAL;
- }
- /* Some basic sanity checks on the arguments passed to divert_ioctl() */
- int check_args(struct divert_cf *div_cf, struct net_device **dev)
- {
- char devname[32];
- int ret;
- if (dev == NULL)
- return -EFAULT;
-
- /* GETVERSION: all other args are unused */
- if (div_cf->cmd == DIVCMD_GETVERSION)
- return 0;
-
- /* Network device index should reasonably be between 0 and 1000 :) */
- if (div_cf->dev_index < 0 || div_cf->dev_index > 1000)
- return -EINVAL;
-
- /* Let's try to find the ifname */
- sprintf(devname, "eth%d", div_cf->dev_index);
- *dev = dev_get_by_name(devname);
-
- /* dev should NOT be null */
- if (*dev == NULL)
- return -EINVAL;
- ret = 0;
- /* user issuing the ioctl must be a super one :) */
- if (!capable(CAP_SYS_ADMIN)) {
- ret = -EPERM;
- goto out;
- }
- /* Device must have a divert_blk member NOT null */
- if ((*dev)->divert == NULL)
- ret = -EINVAL;
- out:
- dev_put(*dev);
- return ret;
- }
- /*
- * control function of the diverter
- */
- #define DVDBG(a)
- printk(KERN_DEBUG "divert_ioctl() line %d %sn", __LINE__, (a))
- int divert_ioctl(unsigned int cmd, struct divert_cf *arg)
- {
- struct divert_cf div_cf;
- struct divert_blk *div_blk;
- struct net_device *dev;
- int ret;
- switch (cmd) {
- case SIOCGIFDIVERT:
- DVDBG("SIOCGIFDIVERT, copy_from_user");
- if (copy_from_user(&div_cf, arg, sizeof(struct divert_cf)))
- return -EFAULT;
- DVDBG("before check_args");
- ret = check_args(&div_cf, &dev);
- if (ret)
- return ret;
- DVDBG("after checkargs");
- div_blk = dev->divert;
-
- DVDBG("befre switch()");
- switch (div_cf.cmd) {
- case DIVCMD_GETSTATUS:
- /* Now, just give the user the raw divert block
- * for him to play with :)
- */
- if (copy_to_user(div_cf.arg1.ptr, dev->divert,
- sizeof(struct divert_blk)))
- return -EFAULT;
- break;
- case DIVCMD_GETVERSION:
- DVDBG("GETVERSION: checking ptr");
- if (div_cf.arg1.ptr == NULL)
- return -EINVAL;
- DVDBG("GETVERSION: copying data to userland");
- if (copy_to_user(div_cf.arg1.ptr,
- sysctl_divert_version, 32))
- return -EFAULT;
- DVDBG("GETVERSION: data copied");
- break;
- default:
- return -EINVAL;
- };
- break;
- case SIOCSIFDIVERT:
- if (copy_from_user(&div_cf, arg, sizeof(struct divert_cf)))
- return -EFAULT;
- ret = check_args(&div_cf, &dev);
- if (ret)
- return ret;
- div_blk = dev->divert;
- switch(div_cf.cmd) {
- case DIVCMD_RESET:
- div_blk->divert = 0;
- div_blk->protos = DIVERT_PROTO_NONE;
- memset(div_blk->tcp_dst, 0,
- MAX_DIVERT_PORTS * sizeof(u16));
- memset(div_blk->tcp_src, 0,
- MAX_DIVERT_PORTS * sizeof(u16));
- memset(div_blk->udp_dst, 0,
- MAX_DIVERT_PORTS * sizeof(u16));
- memset(div_blk->udp_src, 0,
- MAX_DIVERT_PORTS * sizeof(u16));
- return 0;
-
- case DIVCMD_DIVERT:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ENABLE:
- if (div_blk->divert)
- return -EALREADY;
- div_blk->divert = 1;
- break;
- case DIVARG1_DISABLE:
- if (!div_blk->divert)
- return -EALREADY;
- div_blk->divert = 0;
- break;
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_IP:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ENABLE:
- if (div_blk->protos & DIVERT_PROTO_IP)
- return -EALREADY;
- div_blk->protos |= DIVERT_PROTO_IP;
- break;
- case DIVARG1_DISABLE:
- if (!(div_blk->protos & DIVERT_PROTO_IP))
- return -EALREADY;
- div_blk->protos &= ~DIVERT_PROTO_IP;
- break;
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_TCP:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ENABLE:
- if (div_blk->protos & DIVERT_PROTO_TCP)
- return -EALREADY;
- div_blk->protos |= DIVERT_PROTO_TCP;
- break;
- case DIVARG1_DISABLE:
- if (!(div_blk->protos & DIVERT_PROTO_TCP))
- return -EALREADY;
- div_blk->protos &= ~DIVERT_PROTO_TCP;
- break;
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_TCPDST:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ADD:
- return add_port(div_blk->tcp_dst,
- div_cf.arg2.uint16);
-
- case DIVARG1_REMOVE:
- return remove_port(div_blk->tcp_dst,
- div_cf.arg2.uint16);
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_TCPSRC:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ADD:
- return add_port(div_blk->tcp_src,
- div_cf.arg2.uint16);
- case DIVARG1_REMOVE:
- return remove_port(div_blk->tcp_src,
- div_cf.arg2.uint16);
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_UDP:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ENABLE:
- if (div_blk->protos & DIVERT_PROTO_UDP)
- return -EALREADY;
- div_blk->protos |= DIVERT_PROTO_UDP;
- break;
- case DIVARG1_DISABLE:
- if (!(div_blk->protos & DIVERT_PROTO_UDP))
- return -EALREADY;
- div_blk->protos &= ~DIVERT_PROTO_UDP;
- break;
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_UDPDST:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ADD:
- return add_port(div_blk->udp_dst,
- div_cf.arg2.uint16);
- case DIVARG1_REMOVE:
- return remove_port(div_blk->udp_dst,
- div_cf.arg2.uint16);
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_UDPSRC:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ADD:
- return add_port(div_blk->udp_src,
- div_cf.arg2.uint16);
- case DIVARG1_REMOVE:
- return remove_port(div_blk->udp_src,
- div_cf.arg2.uint16);
- default:
- return -EINVAL;
- };
- break;
- case DIVCMD_ICMP:
- switch(div_cf.arg1.int32) {
- case DIVARG1_ENABLE:
- if (div_blk->protos & DIVERT_PROTO_ICMP)
- return -EALREADY;
- div_blk->protos |= DIVERT_PROTO_ICMP;
- break;
- case DIVARG1_DISABLE:
- if (!(div_blk->protos & DIVERT_PROTO_ICMP))
- return -EALREADY;
- div_blk->protos &= ~DIVERT_PROTO_ICMP;
- break;
- default:
- return -EINVAL;
- };
- break;
- default:
- return -EINVAL;
- };
- break;
- default:
- return -EINVAL;
- };
- return 0;
- }
- /*
- * Check if packet should have its dest mac address set to the box itself
- * for diversion
- */
- #define ETH_DIVERT_FRAME(skb)
- memcpy(skb->mac.ethernet, skb->dev->dev_addr, ETH_ALEN);
- skb->pkt_type=PACKET_HOST
-
- void divert_frame(struct sk_buff *skb)
- {
- struct ethhdr *eth = skb->mac.ethernet;
- struct iphdr *iph;
- struct tcphdr *tcph;
- struct udphdr *udph;
- struct divert_blk *divert = skb->dev->divert;
- int i, src, dst;
- unsigned char *skb_data_end = skb->data + skb->len;
- /* Packet is already aimed at us, return */
- if (!memcmp(eth, skb->dev->dev_addr, ETH_ALEN))
- return;
-
- /* proto is not IP, do nothing */
- if (eth->h_proto != htons(ETH_P_IP))
- return;
-
- /* Divert all IP frames ? */
- if (divert->protos & DIVERT_PROTO_IP) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
-
- /* Check for possible (maliciously) malformed IP frame (thanks Dave) */
- iph = (struct iphdr *) skb->data;
- if (((iph->ihl<<2)+(unsigned char*)(iph)) >= skb_data_end) {
- printk(KERN_INFO "divert: malformed IP packet !n");
- return;
- }
- switch (iph->protocol) {
- /* Divert all ICMP frames ? */
- case IPPROTO_ICMP:
- if (divert->protos & DIVERT_PROTO_ICMP) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
- break;
- /* Divert all TCP frames ? */
- case IPPROTO_TCP:
- if (divert->protos & DIVERT_PROTO_TCP) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
- /* Check for possible (maliciously) malformed IP
- * frame (thanx Dave)
- */
- tcph = (struct tcphdr *)
- (((unsigned char *)iph) + (iph->ihl<<2));
- if (((unsigned char *)(tcph+1)) >= skb_data_end) {
- printk(KERN_INFO "divert: malformed TCP packet !n");
- return;
- }
- /* Divert some tcp dst/src ports only ?*/
- for (i = 0; i < MAX_DIVERT_PORTS; i++) {
- dst = divert->tcp_dst[i];
- src = divert->tcp_src[i];
- if ((dst && dst == tcph->dest) ||
- (src && src == tcph->source)) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
- }
- break;
- /* Divert all UDP frames ? */
- case IPPROTO_UDP:
- if (divert->protos & DIVERT_PROTO_UDP) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
- /* Check for possible (maliciously) malformed IP
- * packet (thanks Dave)
- */
- udph = (struct udphdr *)
- (((unsigned char *)iph) + (iph->ihl<<2));
- if (((unsigned char *)(udph+1)) >= skb_data_end) {
- printk(KERN_INFO
- "divert: malformed UDP packet !n");
- return;
- }
- /* Divert some udp dst/src ports only ? */
- for (i = 0; i < MAX_DIVERT_PORTS; i++) {
- dst = divert->udp_dst[i];
- src = divert->udp_src[i];
- if ((dst && dst == udph->dest) ||
- (src && src == udph->source)) {
- ETH_DIVERT_FRAME(skb);
- return;
- }
- }
- break;
- };
- return;
- }