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1 /*
2  * src/nf-queue.c     Monitor netfilter queue events
3  *
4  *	This library is free software; you can redistribute it and/or
5  *	modify it under the terms of the GNU Lesser General Public
6  *	License as published by the Free Software Foundation version 2.1
7  *	of the License.
8  *
9  * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
10  * Copyright (c) 2010  Karl Hiramoto <karl@hiramoto.org>
11  */
12 
13 
14 #include <netlink/cli/utils.h>
15 #include <netlink/cli/link.h>
16 #include <linux/netfilter.h>
17 #include <linux/netfilter/nfnetlink_queue.h>
18 #include <netlink/netfilter/nfnl.h>
19 #include <netlink/netfilter/queue.h>
20 #include <netlink/netfilter/queue_msg.h>
21 
22 static struct nl_sock *nf_sock;
23 
alloc_queue(void)24 static struct nfnl_queue *alloc_queue(void)
25 {
26 	struct nfnl_queue *queue;
27 
28 	queue = nfnl_queue_alloc();
29 	if (!queue)
30 		nl_cli_fatal(ENOMEM, "Unable to allocate queue object");
31 
32 	return queue;
33 }
34 
35 
obj_input(struct nl_object * obj,void * arg)36 static void obj_input(struct nl_object *obj, void *arg)
37 {
38 	struct nfnl_queue_msg *msg = (struct nfnl_queue_msg *) obj;
39 	struct nl_dump_params dp = {
40 		.dp_type = NL_DUMP_STATS,
41 		.dp_fd = stdout,
42 		.dp_dump_msgtype = 1,
43 	};
44 	uint32_t packet_id = nfnl_queue_msg_get_packetid(msg);
45 	static uint32_t next_packet_id = 0;
46 	struct nfnl_queue_msg *lost_msg = NULL;
47 	uint8_t family;
48 	uint16_t group;
49 
50 	if (packet_id > next_packet_id) {
51 		printf("Warning: %d Out of order packets.  Queue or socket overload \n", packet_id - next_packet_id);
52 		group = nfnl_queue_msg_get_group(msg);
53 		family = nfnl_queue_msg_get_family(msg);
54 		lost_msg = nfnl_queue_msg_alloc();
55 
56 		do {
57 			nfnl_queue_msg_set_group(lost_msg, group);
58 			nfnl_queue_msg_set_family(lost_msg, family);
59 			nfnl_queue_msg_set_packetid(lost_msg, next_packet_id);
60 			nfnl_queue_msg_set_verdict(lost_msg, NF_ACCEPT);
61 			nfnl_queue_msg_send_verdict(nf_sock, lost_msg);
62 			next_packet_id++;
63 		} while (packet_id > next_packet_id);
64 
65 		nfnl_queue_msg_put(lost_msg);
66 	}
67 
68 	next_packet_id = packet_id + 1;
69 	nfnl_queue_msg_set_verdict(msg, NF_ACCEPT);
70 	nl_object_dump(obj, &dp);
71 	nfnl_queue_msg_send_verdict(nf_sock, msg);
72 }
73 
event_input(struct nl_msg * msg,void * arg)74 static int event_input(struct nl_msg *msg, void *arg)
75 {
76 	if (nl_msg_parse(msg, &obj_input, NULL) < 0)
77 		fprintf(stderr, "<<EVENT>> Unknown message type\n");
78 
79 	/* Exit nl_recvmsgs_def() and return to the main select() */
80 	return NL_STOP;
81 }
82 
main(int argc,char * argv[])83 int main(int argc, char *argv[])
84 {
85 	struct nl_sock *rt_sock;
86 	struct nl_cache *link_cache;
87 	struct nfnl_queue *queue;
88 	enum nfnl_queue_copy_mode copy_mode;
89 	uint32_t copy_range;
90 	int err = 1;
91 	int family;
92 
93 	nf_sock = nfnl_queue_socket_alloc();
94 	if (nf_sock == NULL)
95 		nl_cli_fatal(ENOBUFS, "Unable to allocate netlink socket");
96 
97 	nl_socket_disable_seq_check(nf_sock);
98 	nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
99 
100 	if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
101 		printf("Usage: nf-queue family group [ copy_mode ] "
102 		       "[ copy_range ]\n");
103 		printf("family: [ inet | inet6 | ... ] \n");
104 		printf("group: the --queue-num arg that you gave to iptables\n");
105 		printf("copy_mode: [ none | meta | packet ] \n");
106 		return 2;
107 	}
108 
109 	nl_cli_connect(nf_sock, NETLINK_NETFILTER);
110 
111 	if ((family = nl_str2af(argv[1])) == AF_UNSPEC)
112 		nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\"", argv[1]);
113 
114 	nfnl_queue_pf_unbind(nf_sock, family);
115 	if ((err = nfnl_queue_pf_bind(nf_sock, family)) < 0)
116 		nl_cli_fatal(err, "Unable to bind logger: %s",
117 			     nl_geterror(err));
118 
119 	queue = alloc_queue();
120 	nfnl_queue_set_group(queue, atoi(argv[2]));
121 
122 	copy_mode = NFNL_QUEUE_COPY_PACKET;
123 	if (argc > 3) {
124 		copy_mode = nfnl_queue_str2copy_mode(argv[3]);
125 		if (copy_mode < 0)
126 			nl_cli_fatal(copy_mode,
127 				     "Unable to parse copy mode \"%s\": %s",
128 				     argv[3], nl_geterror(copy_mode));
129 	}
130 	nfnl_queue_set_copy_mode(queue, copy_mode);
131 
132 	copy_range = 0xFFFF;
133 	if (argc > 4)
134 		copy_range = atoi(argv[4]);
135 	nfnl_queue_set_copy_range(queue, copy_range);
136 
137 	if ((err = nfnl_queue_create(nf_sock, queue)) < 0)
138 		nl_cli_fatal(err, "Unable to bind queue: %s", nl_geterror(err));
139 
140 	rt_sock = nl_cli_alloc_socket();
141 	nl_cli_connect(rt_sock, NETLINK_ROUTE);
142 	link_cache = nl_cli_link_alloc_cache(rt_sock);
143 
144 	nl_socket_set_buffer_size(nf_sock, 1024*127, 1024*127);
145 
146 	while (1) {
147 		fd_set rfds;
148 		int nffd, rtfd, maxfd, retval;
149 
150 		FD_ZERO(&rfds);
151 
152 		maxfd = nffd = nl_socket_get_fd(nf_sock);
153 		FD_SET(nffd, &rfds);
154 
155 		rtfd = nl_socket_get_fd(rt_sock);
156 		FD_SET(rtfd, &rfds);
157 		if (maxfd < rtfd)
158 			maxfd = rtfd;
159 
160 		/* wait for an incoming message on the netlink socket */
161 		retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
162 
163 		if (retval) {
164 			if (FD_ISSET(nffd, &rfds))
165 				nl_recvmsgs_default(nf_sock);
166 			if (FD_ISSET(rtfd, &rfds))
167 				nl_recvmsgs_default(rt_sock);
168 		}
169 	}
170 
171 	return 0;
172 }
173