hunt.c

linux或unix下回话劫持工具

		if (!conn_skip_update(ci, p)) {
			if (p->p_iph->saddr == ci->src_addr &&
			    p->p_iph->daddr == ci->dst_addr &&
			    p->p_hdr.p_tcph->source == ci->src_port &&
			    p->p_hdr.p_tcph->dest == ci->dst_port) {
				/* from source to dest */
			    	if (p->p_hdr.p_tcph->seq == ci->dst.next_d_seq)
					remove_it = 1;
			} else {
				/* from dest to source */
				if (p->p_hdr.p_tcph->seq == ci->src.next_d_seq)
					remove_it = 1;
			}
		}
	}
	if (remove_it) {
		if (ci == hash_remove(&conn_table, key, &uci))
			conn_free(ci);
		hash_unlock(&conn_table);
	} else {
		hash_unlock(&conn_table);
		conn_add_update(p);
	}
}

static void conn_add(struct packet *p)
{
	struct conn_info *ci;
	struct user_conn_info uci;
	unsigned int key;

	fill_uci(&uci, p);
	key = uci_generate_key(&uci);
	hash_lock(&conn_table);
	if ((ci = hash_get(&conn_table, key, &uci)) && 
	    ht_eq(key, ci, &uci) == 1) {
		conn_add_update(p);
#if 0
			ci = hash_remove(&conn_table, key, &uci);
			hash_unlock(&conn_table);
			conn_free(ci);
			hash_lock(&conn_table);
#endif
	} else {
		__conn_add(p, key);
	}
	hash_unlock(&conn_table);
}

static void conn_update_table(struct packet *p, struct ethhdr *ethh, struct iphdr *iph)
{
	struct tcphdr *tcph = p->p_hdr.p_tcph;

	if (tcph->syn && !tcph->ack) {
		if (conn_add_policy(iph, tcph)) {
			conn_add(p);
		}
	} else if (tcph->rst || tcph->fin) {
		#if 0
		if (conn_add_policy(iph, tcph))
		#endif
			conn_del(p);
	} else {
		#if 0
		if (conn_add_policy(iph, tcph))
		#endif
			conn_add_update(p);
	}
}

/*
 * 
 * function lists
 * 
 */
static void process_tcp(struct packet *p)
{
	struct ifunc_item *li;
	struct list_iterator iter;
	
	list_iter_set(&iter, &l_ifunc_tcp);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
}

static void process_udp(struct packet *p)
{
	struct ifunc_item *li;
	struct list_iterator iter;
	
	list_iter_set(&iter, &l_ifunc_udp);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
}

static void process_icmp(struct packet *p)
{
	struct ifunc_item *li;
	struct list_iterator iter;
	
	list_iter_set(&iter, &l_ifunc_icmp);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
}

static void process_arp(struct packet *p)
{
	struct ifunc_item *li;
	struct list_iterator iter;

	list_iter_set(&iter, &l_ifunc_arp);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
}

static void process_ip(struct packet *p)
{
	struct ifunc_item *li;
	struct list_iterator iter;

	list_iter_set(&iter, &l_ifunc_ip);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
}

/*
 * sample of ifunc
 */
#if 0
struct list m_packet_list = LIST_INIT(struct packet, p_next[MODULE_NR]);

void m_func_tcp(struct packet *p)
{
	if (want_it) {
		packet_want(p);
		list_produce(&m_packet_list, p);
	}
}
#endif

static inline void fast_tcp_process(struct packet *p)
{
	struct list_iterator iter;
	struct ifunc_item *li;
	
	list_lock(&l_ifunc_fast_tcp);
	list_iter_set(&iter, &l_ifunc_fast_tcp);
	while ((li = list_iter_get(&iter)))
		li->func(p, li->arg);
	list_iter_end(&iter);
	list_unlock(&l_ifunc_fast_tcp);
}

static void mac_table_update(unsigned int ip, char *mac)
{
	struct mac_info *mi;
	
	hash_lock(&mac_table);
	if ((mi = hash_get(&mac_table, ip, NULL))) {
		if (memcmp(mi->mac, mac, sizeof(mi->mac))) {
			pthread_mutex_lock(&mi->mutex);
			memcpy(mi->mac, mac, sizeof(mi->mac));
			pthread_mutex_unlock(&mi->mutex);
		}
	} else {
		mi = malloc(sizeof(struct mac_info));
		assert(mi);
		memcpy(mi->mac, mac, sizeof(mi->mac));
		pthread_mutex_init(&mi->mutex, NULL);
		hash_put(&mac_table, ip, mi);
	}
	hash_unlock(&mac_table);
}

struct mac_info *mac_info_get(unsigned int ip)
{
	struct mac_info *mi;
	
	hash_lock(&mac_table);
	if ((mi = hash_get(&mac_table, ip, NULL))) {
		pthread_mutex_lock(&mi->mutex);
	}
	hash_unlock(&mac_table);
	return mi;
}

void mac_info_release(struct mac_info *mi)
{
	pthread_mutex_unlock(&mi->mutex);
}

static void mac_arp_learn(struct packet *p)
{
	unsigned int ip;
	char *mac;
	struct arpeth_hdr *arpethh;
	
	arpethh = (struct arpeth_hdr *)(p->p_arph + 1);
	
	if (p->p_arph->ar_op == htons(ARPOP_REPLY)) {
		ip = *(unsigned int *) arpethh->ar_sip;
		mac = arpethh->ar_sha;
	} else {
		ip = *(unsigned int *) arpethh->ar_tip;
		mac = arpethh->ar_tha;
	}
	mac_table_update(ip, mac);
}

static void mac_ip_learn(struct packet *p)
{
	unsigned int ip;
	char *mac;
	
	ip = p->p_iph->saddr;
	mac = p->p_ethh->h_source;
	mac_table_update(ip, mac);
	/*
	 * well, don't learn mac addresses from dst as they can be spoofed
	 * (even though check can be made)
	 */
}

/*
 * 
 * hunt
 * 
 */
unsigned int pkts_received = 0;
unsigned int bytes_received = 0;

void *hunt(void *arg)
{
	struct packet *p;
	struct ethhdr *ethh;
	struct iphdr *iph;
#ifdef WITH_RECVMSG
	struct msghdr msg;
	struct sockaddr_pkt spkt;
	struct iovec iov;
#endif
	pthread_sigmask(SIG_BLOCK, &intr_mask, NULL);
	
	if (verbose)
		printf("hunt pid %d\n", getpid());
	add_telnet_policy();
	if (hash_init(&conn_table, 100, (hash_equal_func)ht_eq)) { /* Initialize hash table of connections */
		perror("hash_init");
		exit(1);
	}
	if (hash_init(&mac_table, 100, NULL)) {
		perror("hash init");
		exit(1);
	}
	linksock = tap(eth_device, 1);                /* Setup link socket */ 
	if (linksock < 0) {
		perror("linksock");
		exit(1);
	}
	packet_preallocate(64);
	
	printf("starting hunt\n");
	setpriority(PRIO_PROCESS, getpid(), -10);
	pthread_mutex_lock(&mutex_hunt_ready);
	hunt_ready = 1;
	pthread_cond_signal(&cond_hunt_ready);
	pthread_mutex_unlock(&mutex_hunt_ready);
	while(1) {
		if (!(p = packet_new())) {
			fprintf(stderr, "can't get free packet - out of memory\n");
			exit(1);
		}
#ifdef WITH_RECVMSG
		memset(&msg, 0, sizeof(msg));
		msg.msg_name = &spkt;
		msg.msg_namelen = sizeof(spkt);
		msg.msg_iovlen = 1;
		msg.msg_iov = &iov;
		iov.iov_base = p->p_raw;
		iov.iov_len = sizeof(p->p_raw);
		if ((p->p_raw_len = recvmsg(linksock, &msg, 0)) >= 0)
#else
		if ((p->p_raw_len = recv(linksock, p->p_raw, sizeof(p->p_raw), 0)) > 0)
#endif
		{
			pkts_received++;
			bytes_received += p->p_raw_len;
			/*
			 * don't do continue or break without packet_free !!
			 */
			ALIGNPOINTERS_ETH(p, ethh);
			p->p_ethh = ethh;
			p->p_timestamp = time(NULL);
			switch (ntohs(ethh->h_proto)) {
			    case ETH_P_IP:
				ALIGNPOINTERS_IP(ethh, iph);
				p->p_iph = iph;
				if (mac_learn_from_ip)
					mac_ip_learn(p);
				process_ip(p);
				switch (iph->protocol) {
				    case IPPROTO_TCP:
					p->p_type = PACKET_TCP;
					ALIGNPOINTERS_TCP(iph, p->p_hdr.p_tcph,
							  p->p_data);
					p->p_data_len = TCP_DATA_LENGTH(iph, p->p_hdr.p_tcph);
					conn_update_table(p, ethh, iph);
					fast_tcp_process(p);
					process_tcp(p);
					break;
				    case IPPROTO_UDP:
					p->p_type = PACKET_UDP;
					ALIGNPOINTERS_UDP(iph, p->p_hdr.p_udph, 
							  p->p_data);
					process_udp(p);
					break;
				    case IPPROTO_ICMP:
					p->p_type = PACKET_ICMP;
					ALIGNPOINTERS_ICMP(iph, p->p_hdr.p_icmph,
							   p->p_data);
					process_icmp(p);
					break;
				}
				break;
			    case ETH_P_ARP:
				p->p_type = PACKET_ARP;
				ALIGNPOINTERS_ARP(ethh, p->p_arph);
				mac_arp_learn(p);
				process_arp(p);
				break;
			}
		}
		packet_free(p);
	}
	return NULL;
}

/*
 * 
 * helper functions
 * 
 */
void print_tcp(struct iphdr *ip, struct tcphdr *tcp)
{
       fprintf(stdout, "%s [%d] seq=(%u) ack=(%u)\t--->\t%s [%d]\n",
	       host_lookup(ip->saddr, hl_mode), ntohs(tcp->source), 
	       (unsigned int) ntohl(tcp->seq), tcp->ack ? (unsigned int) ntohl(tcp->ack_seq) : 0,
	       host_lookup(ip->daddr, hl_mode), ntohs(tcp->dest));
}

static int fill_space_to(char *b, int pos, int where)
{
	if (pos >= 0 && pos < where) {
		return sprintf(b, "%*s", where - pos, "");
	} else
		return 0;
}

int conn_list(struct user_conn_info **ruci, char **rbuf, int with_mac, int with_seq)
{
	struct hash_iterator iter;
	struct conn_info *ci;
	struct user_conn_info *uci;
	int i, count;
	char *b, *b_old, *buf;

	hash_lock(&conn_table);
	count = hash_count(&conn_table);
	if (!count) {
		hash_unlock(&conn_table);
		if (ruci)
			*ruci = NULL;
		if (rbuf)
			*rbuf = NULL;
		return 0;
	}
	if (rbuf) {
		assert(buf = malloc(count * 512));
		b = buf;
	} else
		b = buf = NULL;
	if (ruci)
		assert(uci = malloc(count * sizeof(struct user_conn_info)));
	else
		uci = NULL;
	i = 0;
	hash_iter_set(&iter, &conn_table);
	while ((ci = hash_iter_get(&iter, NULL)) && i < count) {
		if (b) {
			b_old = b;
			b += sprintf(b, "%d) %s [%s]", i,
			       	     host_lookup(ci->src_addr, hl_mode),
				     port_lookup(ci->src_port, hl_mode));
			b += fill_space_to(b, b - b_old, 30);
			b += sprintf(b, " --> ");
			b += sprintf(b, "%s [%s]\n",
			             host_lookup(ci->dst_addr, hl_mode),
				     port_lookup(ci->dst_port, hl_mode));
			if (with_seq) {
				b_old = b;
				b += sprintf(b, "     seq=(%u) ack=(%u)",
					(unsigned int) ntohl(ci->src.next_seq), (unsigned int) ntohl(ci->src.next_d_seq));
				b += fill_space_to(b, b - b_old, 45);
				b += sprintf(b, " seq=(%u) ack=(%u)\n",
					(unsigned int) ntohl(ci->dst.next_seq), (unsigned int) ntohl(ci->dst.next_d_seq));
			}
			if (with_mac) {
				b_old = b;
				b += sprintf(b, "     src mac=");
				b += sprintf_eth_mac(b, ci->src.src_mac);
				b += fill_space_to(b, b - b_old, 45);
				b += sprintf(b, " src mac=");
				b += sprintf_eth_mac(b, ci->dst.src_mac);
				b += sprintf(b, "\n");
				
				b_old = b;
				b += sprintf(b, "     dst mac=");
				b += sprintf_eth_mac(b, ci->src.dst_mac);
				b += fill_space_to(b, b - b_old, 45);
				b += sprintf(b, " dst mac=");
				b += sprintf_eth_mac(b, ci->dst.dst_mac);
				b += sprintf(b, "\n");
			}
		}
		if (uci) {
			uci[i].src_addr = ci->src_addr;
			uci[i].dst_addr = ci->dst_addr;
			uci[i].src_port = ci->src_port;
			uci[i].dst_port = ci->dst_port;
		}
		i++;
	}
	hash_iter_end(&iter);
	hash_unlock(&conn_table);
	
	if (ruci)
		*ruci = uci;
	if (rbuf)
		*rbuf = buf;
	return count;
}

void print_mac_table(void)
{
	struct hash_iterator hi;
	char buf[BUFSIZE];
	unsigned int key;
	struct mac_info *mi;
	int i = 0;
	
	printf("--- mac table ---\n");
	hash_iter_set(&hi, &mac_table);
	while ((mi = hash_iter_get(&hi, &key))) {
		sprintf_eth_mac(buf, mi->mac);
		printf("%-24s %s\n", host_lookup(key, hl_mode), buf);
		if (++i % lines_o == 0)
			lines_o_press_key();
	}
	hash_iter_end(&hi);
}

void print_user_conn_info(struct user_conn_info *uci, int count)
{
	int i, ret;
	
	for (i = 0; i < count; i++) {
		ret = printf("%d) %s [%s]", i,
		       	     host_lookup(uci->src_addr, hl_mode),
			     port_lookup(uci->src_port, hl_mode));
		printf("%*s", 25 - ret > 0 ? 20 - ret : 0, "");
		printf(" --> ");
		printf("%s [%s]\n", 
		       host_lookup(uci->dst_addr, hl_mode),
		       port_lookup(uci->dst_port, hl_mode));
	}
}