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how to send a ping packet
i have made a module which aims to send the ping packet using ioctl command from user space(application). however i am not sure whether its sending a ping packet or not because when i try to recieve a packet thru hook function there is no reply to it. i am sending the ping packet to router(192.168.1.1).following is my code its compiling and running w/o errors:
int device_ioctl(struct net_device *dev,struct ifreq *ifr, int cmd)
{
int len;
//printk("%s , %d",__func__,__LINE__);
switch(cmd)
{
case SIOCDEVPRIVATE:
printk("here it is : %s: %d\n",__func__,__LINE__);
break;
case WLAN_TRANSMIT :
icmp.type = ICMP_ECHO;
icmp.code = 0;
icmp.un.echo.sequence = i++;
icmp.un.echo.id = current->pid & 0xFFFF;
printk(KERN_ALERT"ID::%X\n",icmp.un.echo.id);
ip4.protocol = 0x01; //for icmp protocol
ip4.tos = 0x00;
ip4.frag_off = 0;
ip4.daddr = in_aton(procfs_buffer);
ip4.saddr = in_aton(ifr->ifr_addr.sa_data);
len = sizeof(data);
skb = dev_alloc_skb(1500);
skb->dev = __dev_get_by_name(&init_net,"wlan0");
skb_reserve(skb,NET_IP_ALIGN); //header of 2 bytes; increments tail and data pointer
skb->data = skb_put(skb,sizeof(len)); // increments all pointer or adds data
memcpy(data,skb->data,len);
wdev = skb->dev;
skb->transport_header =skb_push(skb,sizeof(icmp));
memset(skb->transport_header,0,sizeof(struct icmphdr));
memcpy(skb->transport_header,&icmp,sizeof(struct icmphdr));
skb->network_header=skb_push(skb,sizeof(ip4));
memset(skb->network_header,0,sizeof(struct iphdr));
memcpy(skb->network_header,&ip4,sizeof(struct iphdr));
// printk("i::%d\n",i);
// skb->mac_header = skb_push(skb,6*sizeof(0xFF));
// memset(skb->mac_header,0xFF,6*sizeof(0xFF));
dev_queue_xmit(skb);
// kfree(skb);
}
return 0;
}
unsigned int hook_func(unsigned int hooknum, struct sk_buff *skb1, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff *))
{
struct sk_buff *sock_buff;
struct iphdr *ip1;
struct icmphdr *icmp1;
sock_buff = skb1;
//printk("ihere we are::%s,%d\n",__func__,__LINE__);
ip1 = (struct iphdr *)skb_network_header(sock_buff);
//printk(KERN_ALERT"proto:%d,addr:%X::%X\n",ip1->protocol,ip1->saddr,ip1->daddr);
if(ip1->protocol==1)
{
printk(KERN_ALERT"proto:%d,addr:%X::%X\n",ip1->protocol,ip1->saddr,ip1->daddr);
icmp1 = (struct icmphdr *)skb_transport_header(sock_buff);
printk(KERN_ALERT"reply type: %c,,seq : %04X\n",icmp1->type,icmp1->un.echo.id);
}
// kfree(sock_buff);
return NF_ACCEPT;
}
hook function is working fine but not sure how to send a ping packet(in doubt because not getting a reply packet).
regards
karan
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