使用dev_queue_xmit發送定制報文

使用dev_queue_xmit發送定制報文
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來源： necofang.cublog.cn
本文通過實例講述如何使用dev_queue_xmit來直接發送udp和tcp報文。示例代碼在linux-2.6.24上可以編譯執行。
轉載注:
的確不錯， 基本可以運行，我用的Fdora 8， 2.6.23.1-42-fc8,
內核API有點不同dev_get_by_name(char * name)
UDP那裡是ICMP包，源192.168.1.10 -> 目的 192.168.1.197 的echo ping request
使用這還需自己改改
＝＝＝＝＝＝＝＝＝＝＝我 是 分 割 線 ＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
用於調試的代碼：
#define MSG_DEBUG(msg...) printk(KERN_INFO "cup: " msg)
#define IP_PARTS_NATIVE(n) /
(unsigned int)((n)&0xFF), /
(unsigned int)((n)>>8)&0xFF, /
(unsigned int)((n)>>16)&0xFF, /
(unsigned int)((n)>>24)&0xFF
#define XMIT(skb, rt) /
NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, (skb), NULL, /
(rt)->u.dst.dev, dst_output);
void dump_block(char *s, caddr_t bb, int len)
{
int i;
unsigned char *b = bb;
printk(KERN_INFO "dump: ""at %s, len=%d:/n", s, len);
for(i = 0; i < len; i++ /*, c++*/) {
if(!(i % 16)) {
printk(KERN_INFO "dump: @%03x:", i);
}
printk(" %02x", b[i]);
if(!((i + 1) % 16)) {
printk("/n");
}
}
if(i % 16) {
printk("/n");
}
}
void print_ip(struct iphdr *ip)
{
printk(KERN_INFO "debug: IP:");
printk(" ihl:%d", ip->ihl << 2);
printk(" ver:%d", ip->version);
printk(" tos:%d", ip->tos);
printk(" tlen:%d", ntohs(ip->tot_len));
printk(" id:%d", ntohs(ip->id));
printk(" %s%s%sfrag_off:%d",
ip->frag_off & __constant_htons(IP_CE) ? "CE " : "",
ip->frag_off & __constant_htons(IP_DF) ? "DF " : "",
ip->frag_off & __constant_htons(IP_MF) ? "MF " : "",
(ntohs(ip->frag_off) & IP_OFFSET) << 3);
printk(" ttl:%d", ip->ttl);
printk(" proto:%d", ip->protocol);
if(ip->protocol == IPPROTO_UDP)
printk(" (UDP)");
if(ip->protocol == IPPROTO_TCP)
printk(" (TCP)");
if(ip->protocol == IPPROTO_ICMP)
printk(" (ICMP)");
if(ip->protocol == IPPROTO_ESP)
printk(" (ESP)");
if(ip->protocol == IPPROTO_AH)
printk(" (AH)");
if(ip->protocol == IPPROTO_COMP)
printk(" (COMP)");
printk(" chk:%d", ntohs(ip->check));
printk(" saddr:%d.%d.%d.%d", IP_PARTS_NATIVE(ip->saddr));
if(ip->protocol == IPPROTO_UDP)
printk(":%d", __constant_htons(((struct udphdr*)((caddr_t)ip + (ip->ihl << 2)))->source));
if(ip->protocol == IPPROTO_TCP)
printk (":%d", __constant_htons(((struct tcphdr*)((caddr_t)ip + (ip->ihl << 2)))->source));
printk(" daddr:%d.%d.%d.%d", IP_PARTS_NATIVE(ip->daddr));
if(ip->protocol == IPPROTO_UDP)
printk(":%d", __constant_htons(((struct udphdr*)((u_char * )ip + (ip->ihl << 2)))->dest));
if(ip->protocol == IPPROTO_TCP)
printk(":%d", __constant_htons(((struct tcphdr*)((caddr_t)ip + (ip->ihl << 2)))->dest));
if(ip->protocol == IPPROTO_ICMP)
printk(" type:code=%d:%d", ((struct icmphdr*)((caddr_t)ip + (ip->ihl << 2)))->type,
((struct icmphdr*)((caddr_t)ip + (ip->ihl << 2)))->code);
printk("/n");
//dump_block ("PACKET DUMP", (caddr_t)ip, ntohs(ip->tot_len));
}skb destroy
void cup_destroy (struct sk_buff *skb)
{
dev_put(skb->dev);
} tcp輸出
int cp_dev_xmit_tcp (char * eth, u_char * smac, u_char * dmac,
u_char * pkt, int pkt_len,
u_long sip, u_long dip,
u_short sport, u_short dport, u_long seq, u_long ack_seq, u_char psh, u_char fin)
{
struct sk_buff * skb = NULL;
struct net_device * dev = NULL;
struct ethhdr * ethdr = NULL;
struct iphdr * iph = NULL;
struct tcphdr * tcph = NULL;
u_char * pdata = NULL;
int nret = 1;
if (NULL == smac || NULL == dmac) goto out;
dev = dev_get_by_name (&init_net , eth);
if (NULL == dev) goto out;
skb = alloc_skb (pkt_len + sizeof (struct iphdr) + sizeof (struct tcphdr) + LL_RESERVED_SPACE (dev), GFP_ATOMIC);
if (NULL == skb) goto out;
skb_reserve (skb, LL_RESERVED_SPACE (dev));
skb->dev = dev;
skb->pkt_type = PACKET_OTHERHOST;
skb->protocol = __constant_htons(ETH_P_IP);
skb->ip_summed = CHECKSUM_NONE;
skb->destructor = cup_destroy;
skb->priority = 0;
skb->network_header = skb_put (skb, sizeof (struct iphdr));
skb->transport_header = skb_put (skb, sizeof (struct tcphdr));
pdata = skb_put (skb, pkt_len);
{
if (NULL != pkt) memcpy (pdata, pkt, pkt_len);
}
{
tcph = (struct tcphdr *) skb->transport_header;
memset (tcph, 0, sizeof (struct tcphdr));
tcph->source = sport;
tcph->dest = dport;
tcph->seq = seq;
tcph->ack_seq = ack_seq;
tcph->doff = 5;
tcph->psh = psh;
tcph->fin = fin;
tcph->ack = 1;
tcph->window = __constant_htons (65535);
skb->csum = 0;
tcph->check = 0;
}
{
iph = (struct iphdr*) skb->network_header;
iph->version = 4;
iph->ihl = sizeof(struct iphdr)>>2;
iph->frag_off = 0;
iph->protocol = IPPROTO_TCP;
iph->tos = 0;
iph->daddr = dip;
iph->saddr = sip;
iph->ttl = 0x40;
iph->tot_len = __constant_htons(skb->len);
iph->check = 0;
}
skb->csum = skb_checksum (skb, iph->ihl*4, skb->len - iph->ihl * 4, 0);
tcph->check = csum_tcpudp_magic (sip, dip, skb->len - iph->ihl * 4, IPPROTO_TCP, skb->csum);
ip_send_check(iph);
skb->mac_header = skb_push (skb, 14);
{ //eth header
ethdr = (struct ethhdr *) skb->mac_header;
memcpy (ethdr->h_dest, dmac, ETH_ALEN);
memcpy (ethdr->h_source, smac, ETH_ALEN);
ethdr->h_proto = __constant_htons (ETH_P_IP);
}
print_ip ((struct iphdr *)skb->network_header);
dump_block ("before xmit", skb->data, skb->len);
if (0 > dev_queue_xmit(skb)) goto out;
MSG_DEBUG ("dev_queue_xmit succ/n");
MSG_DEBUG ("skb->len = %d/n", skb->len);
nret = 0;
out:
if (0 != nret && NULL != skb) {dev_put (dev); kfree_skb (skb);}
return (nret);
}udp輸出
void my_cup (void)
{
struct sk_buff * skb = NULL;
struct net_device * dev = NULL;
u_char pkt_eth [14] = {
0x00, 0x1E, 0x37, 0x82, 0x9D, 0xFF, 0x00, 0x0C,
0x29, 0xF1, 0xF9, 0x87, 0x08, 0x00 }; //eth
u_char pkt_ip [20] = {
0x45, 0x00,
0x00, 0x54, 0x00, 0x00, 0x40, 0x00, 0x40, 0x01,
0xB6, 0x90, 0xC0, 0xA8, 0x01, 0x67, 0xC0, 0xA8,
0x01, 0x61 }; //ip
u_char pkt_icmp [8] = {
0x08, 0x00, 0x2A, 0x7D, 0x1B, 0x08, //icmp
0x00, 0x01 };
u_char pkt_data [56] = {
0x69, 0xD5, 0x43, 0x48, 0x14, 0x59,
0x06, 0x00, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D,
0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D,
0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25,
0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D,
0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
0x36, 0x37
};
MSG_DEBUG ("send /n");
dev = dev_get_by_name (&init_net , "eth2");
MSG_DEBUG ("dev name : %s/n", dev->name);
skb = alloc_skb (100, GFP_ATOMIC);
//skb = dev_alloc_skb (100);
if (NULL == skb) return;
skb->dev = dev;
skb->pkt_type = PACKET_OTHERHOST;//PACKET_OUTGOING;
skb->protocol = __constant_htons(ETH_P_IP);
skb->ip_summed = CHECKSUM_NONE;
skb->destructor = cup_destroy;
skb->priority = 0;
skb_reserve (skb, 16);
memcpy (skb_push (skb, 14), pkt_eth, 14);
skb->network_header = skb_put (skb, sizeof (struct iphdr));
memcpy (skb->network_header, pkt_ip, sizeof (struct iphdr));
skb->transport_header = skb_put (skb, sizeof (struct icmphdr));
memcpy (skb->transport_header, pkt_icmp, sizeof (struct icmphdr));
memcpy (skb_put (skb, 56), pkt_data, 56);
MSG_DEBUG ("skb->network_header = %p /n", skb->network_header);
MSG_DEBUG ("skb->data %p /n", skb->data);
MSG_DEBUG ("skb->tail %p /n", skb->tail);
skb->tail = skb->data + 98;
MSG_DEBUG ("skb->tail %p /n", skb->tail);
print_ip ((struct iphdr *)skb->network_header);
dump_block ("before xmit", skb->data, skb->len);
if (0 > dev_queue_xmit(skb)) { kfree_skb (skb); dev_put(dev); MSG_DEBUG ("dev_queue_xmit error/n"); }
else {
MSG_DEBUG ("dev_queue_xmit succ/n");
MSG_DEBUG ("skb->len = %d/n", skb->len);
}
return;
}