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1 /*
2  * src/nf-log.c     Monitor netfilter log 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) 2003-2008 Thomas Graf <tgraf@suug.ch>
10  * Copyright (c) 2007 Philip Craig <philipc@snapgear.com>
11  * Copyright (c) 2007 Secure Computing Corporation
12  */
13 
14 #include <netlink/cli/utils.h>
15 #include <netlink/cli/link.h>
16 #include <linux/netfilter/nfnetlink_log.h>
17 #include <netlink/netfilter/nfnl.h>
18 #include <netlink/netfilter/log.h>
19 
alloc_log(void)20 static struct nfnl_log *alloc_log(void)
21 {
22 	struct nfnl_log *log;
23 
24 	log = nfnl_log_alloc();
25 	if (!log)
26 		nl_cli_fatal(ENOMEM, "Unable to allocate log object");
27 
28 	return log;
29 }
30 
obj_input(struct nl_object * obj,void * arg)31 static void obj_input(struct nl_object *obj, void *arg)
32 {
33 	struct nl_dump_params dp = {
34 		.dp_type = NL_DUMP_STATS,
35 		.dp_fd = stdout,
36 		.dp_dump_msgtype = 1,
37 	};
38 
39 	nl_object_dump(obj, &dp);
40 }
41 
event_input(struct nl_msg * msg,void * arg)42 static int event_input(struct nl_msg *msg, void *arg)
43 {
44 	if (nl_msg_parse(msg, &obj_input, NULL) < 0)
45 		fprintf(stderr, "<<EVENT>> Unknown message type\n");
46 
47 	/* Exit nl_recvmsgs_def() and return to the main select() */
48 	return NL_STOP;
49 }
50 
main(int argc,char * argv[])51 int main(int argc, char *argv[])
52 {
53 	struct nl_sock *nf_sock;
54 	struct nl_sock *rt_sock;
55         struct nl_cache *link_cache;
56 	struct nfnl_log *log;
57 	enum nfnl_log_copy_mode copy_mode;
58 	uint32_t copy_range;
59 	int err;
60 	int family;
61 
62 	nf_sock = nl_cli_alloc_socket();
63 	nl_socket_disable_seq_check(nf_sock);
64 	nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
65 
66 	if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
67 		printf("Usage: nf-log family group [ copy_mode ] "
68 		       "[copy_range] \n");
69 		return 2;
70 	}
71 
72 	nl_cli_connect(nf_sock, NETLINK_NETFILTER);
73 
74 	family = nl_str2af(argv[1]);
75 	if (family == AF_UNSPEC)
76 		nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\": %s",
77 			     argv[1], nl_geterror(family));
78 
79 	nfnl_log_pf_unbind(nf_sock, family);
80 	if ((err = nfnl_log_pf_bind(nf_sock, family)) < 0)
81 		nl_cli_fatal(err, "Unable to bind logger: %s",
82 			     nl_geterror(err));
83 
84 	log = alloc_log();
85 	nfnl_log_set_group(log, atoi(argv[2]));
86 
87 	copy_mode = NFNL_LOG_COPY_META;
88 	if (argc > 3) {
89 		copy_mode = nfnl_log_str2copy_mode(argv[3]);
90 		if (copy_mode < 0)
91 			nl_cli_fatal(copy_mode,
92 				     "Unable to parse copy mode \"%s\": %s",
93 				     argv[3], nl_geterror(copy_mode));
94 	}
95 	nfnl_log_set_copy_mode(log, copy_mode);
96 
97 	copy_range = 0xFFFF;
98 	if (argc > 4)
99 		copy_range = atoi(argv[4]);
100 	nfnl_log_set_copy_range(log, copy_range);
101 
102 	if ((err = nfnl_log_create(nf_sock, log)) < 0)
103 		nl_cli_fatal(err, "Unable to bind instance: %s",
104 			     nl_geterror(err));
105 
106 	{
107 		struct nl_dump_params dp = {
108 			.dp_type = NL_DUMP_STATS,
109 			.dp_fd = stdout,
110 			.dp_dump_msgtype = 1,
111 		};
112 
113 		printf("log params: ");
114 		nl_object_dump((struct nl_object *) log, &dp);
115 	}
116 
117 	rt_sock = nl_cli_alloc_socket();
118 	nl_cli_connect(rt_sock, NETLINK_ROUTE);
119 	link_cache = nl_cli_link_alloc_cache(rt_sock);
120 
121 	while (1) {
122 		fd_set rfds;
123 		int nffd, rtfd, maxfd, retval;
124 
125 		FD_ZERO(&rfds);
126 
127 		maxfd = nffd = nl_socket_get_fd(nf_sock);
128 		FD_SET(nffd, &rfds);
129 
130 		rtfd = nl_socket_get_fd(rt_sock);
131 		FD_SET(rtfd, &rfds);
132 		if (maxfd < rtfd)
133 			maxfd = rtfd;
134 
135 		/* wait for an incoming message on the netlink nf_socket */
136 		retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
137 
138 		if (retval) {
139 			if (FD_ISSET(nffd, &rfds))
140 				nl_recvmsgs_default(nf_sock);
141 			if (FD_ISSET(rtfd, &rfds))
142 				nl_recvmsgs_default(rt_sock);
143 		}
144 	}
145 
146 	return 0;
147 }
148