libnl 3.5.0

nf-log.c
1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3 * src/nf-log.c Monitor netfilter log events
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation version 2.1
8 * of the License.
9 *
10 * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
11 * Copyright (c) 2007 Philip Craig <philipc@snapgear.com>
12 * Copyright (c) 2007 Secure Computing Corporation
13 */
14
15 #include <netlink/cli/utils.h>
16 #include <netlink/cli/link.h>
17 #include <netlink/netfilter/nfnl.h>
18 #include <netlink/netfilter/log.h>
19
20 #include <linux/netfilter/nfnetlink_log.h>
21 #include <linux/netlink.h>
22
23 static struct nfnl_log *alloc_log(void)
24 {
25 struct nfnl_log *log;
26
27 log = nfnl_log_alloc();
28 if (!log)
29 nl_cli_fatal(ENOMEM, "Unable to allocate log object");
30
31 return log;
32 }
33
34 static void obj_input(struct nl_object *obj, void *arg)
35 {
36 struct nl_dump_params dp = {
37 .dp_type = NL_DUMP_STATS,
38 .dp_fd = stdout,
39 .dp_dump_msgtype = 1,
40 };
41
42 nl_object_dump(obj, &dp);
43 }
44
45 static int event_input(struct nl_msg *msg, void *arg)
46 {
47 if (nl_msg_parse(msg, &obj_input, NULL) < 0)
48 fprintf(stderr, "<<EVENT>> Unknown message type\n");
49
50 /* Exit nl_recvmsgs_def() and return to the main select() */
51 return NL_STOP;
52 }
53
54 int main(int argc, char *argv[])
55 {
56 struct nl_sock *nf_sock;
57 struct nl_sock *rt_sock;
58 struct nfnl_log *log;
59 int copy_mode;
60 uint32_t copy_range;
61 int err;
62 int family;
63
64 nf_sock = nl_cli_alloc_socket();
65 nl_socket_disable_seq_check(nf_sock);
66 nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
67
68 if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
69 printf("Usage: nf-log family group [ copy_mode ] "
70 "[copy_range] \n");
71 return 2;
72 }
73
74 nl_cli_connect(nf_sock, NETLINK_NETFILTER);
75
76 family = nl_str2af(argv[1]);
77 if (family == AF_UNSPEC)
78 nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\": %s",
79 argv[1], nl_geterror(family));
80
81 nfnl_log_pf_unbind(nf_sock, family);
82 if ((err = nfnl_log_pf_bind(nf_sock, family)) < 0)
83 nl_cli_fatal(err, "Unable to bind logger: %s",
84 nl_geterror(err));
85
86 log = alloc_log();
87 nfnl_log_set_group(log, atoi(argv[2]));
88
89 copy_mode = NFNL_LOG_COPY_META;
90 if (argc > 3) {
91 copy_mode = nfnl_log_str2copy_mode(argv[3]);
92 if (copy_mode < 0)
93 nl_cli_fatal(copy_mode,
94 "Unable to parse copy mode \"%s\": %s",
95 argv[3], nl_geterror(copy_mode));
96 }
97 nfnl_log_set_copy_mode(log, copy_mode);
98
99 copy_range = 0xFFFF;
100 if (argc > 4)
101 copy_range = atoi(argv[4]);
102 nfnl_log_set_copy_range(log, copy_range);
103
104 if ((err = nfnl_log_create(nf_sock, log)) < 0)
105 nl_cli_fatal(err, "Unable to bind instance: %s",
106 nl_geterror(err));
107
108 {
109 struct nl_dump_params dp = {
110 .dp_type = NL_DUMP_STATS,
111 .dp_fd = stdout,
112 .dp_dump_msgtype = 1,
113 };
114
115 printf("log params: ");
116 nl_object_dump((struct nl_object *) log, &dp);
117 }
118
119 rt_sock = nl_cli_alloc_socket();
120 nl_cli_connect(rt_sock, NETLINK_ROUTE);
121 nl_cli_link_alloc_cache(rt_sock);
122
123 while (1) {
124 fd_set rfds;
125 int nffd, rtfd, maxfd, retval;
126
127 FD_ZERO(&rfds);
128
129 maxfd = nffd = nl_socket_get_fd(nf_sock);
130 FD_SET(nffd, &rfds);
131
132 rtfd = nl_socket_get_fd(rt_sock);
133 FD_SET(rtfd, &rfds);
134 if (maxfd < rtfd)
135 maxfd = rtfd;
136
137 /* wait for an incoming message on the netlink nf_socket */
138 retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
139
140 if (retval) {
141 if (FD_ISSET(nffd, &rfds))
142 nl_recvmsgs_default(nf_sock);
143 if (FD_ISSET(rtfd, &rfds))
144 nl_recvmsgs_default(rt_sock);
145 }
146 }
147
148 return 0;
149 }
NL_CB_CUSTOM
Customized handler specified by the user.
Definition: handlers.h:83
nl_socket_get_fd
int nl_socket_get_fd(const struct nl_sock *sk)
Return the file descriptor of the backing socket.
Definition: socket.c:584
nl_dump_params::dp_type
enum nl_dump_type dp_type
Specifies the type of dump that is requested.
Definition: types.h:38
NL_STOP
Stop parsing altogether and discard remaining messages.
Definition: handlers.h:68
nl_socket_modify_cb
int nl_socket_modify_cb(struct nl_sock *sk, enum nl_cb_type type, enum nl_cb_kind kind, nl_recvmsg_msg_cb_t func, void *arg)
Modify the callback handler associated with the socket.
Definition: socket.c:771
nl_object_dump
void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
Dump this object according to the specified parameters.
Definition: object.c:289
nl_socket_disable_seq_check
void nl_socket_disable_seq_check(struct nl_sock *sk)
Disable sequence number checking.
Definition: socket.c:283
nl_recvmsgs_default
int nl_recvmsgs_default(struct nl_sock *sk)
Receive a set of message from a netlink socket using handlers in nl_sock.
Definition: nl.c:1094
NL_CB_VALID
Message is valid.
Definition: handlers.h:95
nl_cli_fatal
void nl_cli_fatal(int err, const char *fmt,...)
Print error message and quit application.
Definition: utils.c:78
nl_dump_params
Dumping parameters.
Definition: types.h:33
NL_DUMP_STATS
Dump all attributes including statistics.
Definition: types.h:24