1 /* This example is placed in the public domain. */
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5 #include <time.h>
6 #include <arpa/inet.h>
7
8 #include <libmnl/libmnl.h>
9 #include <linux/if.h>
10 #include <linux/if_link.h>
11 #include <linux/rtnetlink.h>
12
data_attr_cb(const struct nlattr * attr,void * data)13 static int data_attr_cb(const struct nlattr *attr, void *data)
14 {
15 const struct nlattr **tb = data;
16 int type = mnl_attr_get_type(attr);
17
18 /* skip unsupported attribute in user-space */
19 if (mnl_attr_type_valid(attr, IFLA_MAX) < 0)
20 return MNL_CB_OK;
21
22 switch(type) {
23 case IFLA_ADDRESS:
24 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
25 perror("mnl_attr_validate");
26 return MNL_CB_ERROR;
27 }
28 break;
29 case IFLA_MTU:
30 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
31 perror("mnl_attr_validate");
32 return MNL_CB_ERROR;
33 }
34 break;
35 case IFLA_IFNAME:
36 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
37 perror("mnl_attr_validate");
38 return MNL_CB_ERROR;
39 }
40 break;
41 }
42 tb[type] = attr;
43 return MNL_CB_OK;
44 }
45
data_cb(const struct nlmsghdr * nlh,void * data)46 static int data_cb(const struct nlmsghdr *nlh, void *data)
47 {
48 struct nlattr *tb[IFLA_MAX+1] = {};
49 struct ifinfomsg *ifm = mnl_nlmsg_get_payload(nlh);
50
51 printf("index=%d type=%d flags=%d family=%d ",
52 ifm->ifi_index, ifm->ifi_type,
53 ifm->ifi_flags, ifm->ifi_family);
54
55 if (ifm->ifi_flags & IFF_RUNNING)
56 printf("[RUNNING] ");
57 else
58 printf("[NOT RUNNING] ");
59
60 mnl_attr_parse(nlh, sizeof(*ifm), data_attr_cb, tb);
61 if (tb[IFLA_MTU]) {
62 printf("mtu=%d ", mnl_attr_get_u32(tb[IFLA_MTU]));
63 }
64 if (tb[IFLA_IFNAME]) {
65 printf("name=%s ", mnl_attr_get_str(tb[IFLA_IFNAME]));
66 }
67 if (tb[IFLA_ADDRESS]) {
68 uint8_t *hwaddr = mnl_attr_get_payload(tb[IFLA_ADDRESS]);
69 int i;
70
71 printf("hwaddr=");
72 for (i=0; i<mnl_attr_get_payload_len(tb[IFLA_ADDRESS]); i++) {
73 printf("%.2x", hwaddr[i] & 0xff);
74 if (i+1 != mnl_attr_get_payload_len(tb[IFLA_ADDRESS]))
75 printf(":");
76 }
77 }
78 printf("\n");
79 return MNL_CB_OK;
80 }
81
main(void)82 int main(void)
83 {
84 char buf[MNL_SOCKET_DUMP_SIZE];
85 unsigned int seq, portid;
86 struct mnl_socket *nl;
87 struct nlmsghdr *nlh;
88 struct rtgenmsg *rt;
89 int ret;
90
91 nlh = mnl_nlmsg_put_header(buf);
92 nlh->nlmsg_type = RTM_GETLINK;
93 nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
94 nlh->nlmsg_seq = seq = time(NULL);
95 rt = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtgenmsg));
96 rt->rtgen_family = AF_PACKET;
97
98 nl = mnl_socket_open(NETLINK_ROUTE);
99 if (nl == NULL) {
100 perror("mnl_socket_open");
101 exit(EXIT_FAILURE);
102 }
103
104 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
105 perror("mnl_socket_bind");
106 exit(EXIT_FAILURE);
107 }
108 portid = mnl_socket_get_portid(nl);
109
110 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
111 perror("mnl_socket_sendto");
112 exit(EXIT_FAILURE);
113 }
114
115 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
116 while (ret > 0) {
117 ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
118 if (ret <= MNL_CB_STOP)
119 break;
120 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
121 }
122 if (ret == -1) {
123 perror("error");
124 exit(EXIT_FAILURE);
125 }
126
127 mnl_socket_close(nl);
128
129 return 0;
130 }
131