1 /* This example is placed in the public domain. */
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <string.h>
5 #include <unistd.h>
6 #include <time.h>
7 #include <arpa/inet.h>
8
9 #include <libmnl/libmnl.h>
10 #include <linux/if.h>
11 #include <linux/if_link.h>
12 #include <linux/rtnetlink.h>
13
data_attr_cb(const struct nlattr * attr,void * data)14 static int data_attr_cb(const struct nlattr *attr, void *data)
15 {
16 const struct nlattr **tb = data;
17 int type = mnl_attr_get_type(attr);
18
19 /* skip unsupported attribute in user-space */
20 if (mnl_attr_type_valid(attr, NDA_MAX) < 0)
21 return MNL_CB_OK;
22
23 switch(type) {
24 case NDA_DST:
25 case NDA_LLADDR:
26 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
27 perror("mnl_attr_validate");
28 return MNL_CB_ERROR;
29 }
30 break;
31 }
32 tb[type] = attr;
33 return MNL_CB_OK;
34 }
35
data_cb(const struct nlmsghdr * nlh,void * data)36 static int data_cb(const struct nlmsghdr *nlh, void *data)
37 {
38 struct nlattr *tb[NDA_MAX + 1] = {};
39 struct ndmsg *ndm = mnl_nlmsg_get_payload(nlh);
40
41 printf("index=%d family=%d ", ndm->ndm_ifindex, ndm->ndm_family);
42
43 mnl_attr_parse(nlh, sizeof(*ndm), data_attr_cb, tb);
44 printf("dst=");
45 if (tb[NDA_DST]) {
46 void *addr = mnl_attr_get_payload(tb[NDA_DST]);
47 char out[INET6_ADDRSTRLEN];
48
49 if (inet_ntop(ndm->ndm_family, addr, out, sizeof(out)))
50 printf("%s ", out);
51 }
52
53 mnl_attr_parse(nlh, sizeof(*ndm), data_attr_cb, tb);
54 printf("lladdr=");
55 if (tb[NDA_LLADDR]) {
56 void *addr = mnl_attr_get_payload(tb[NDA_LLADDR]);
57 unsigned char lladdr[6] = {0};
58
59 if (memcpy(&lladdr, addr, 6))
60 printf("%02x:%02x:%02x:%02x:%02x:%02x ",
61 lladdr[0], lladdr[1], lladdr[2],
62 lladdr[3], lladdr[4], lladdr[5]);
63 }
64
65 printf("state=");
66 switch(ndm->ndm_state) {
67 case NUD_INCOMPLETE:
68 printf("incomplete ");
69 break;
70 case NUD_REACHABLE:
71 printf("reachable ");
72 break;
73 case NUD_STALE:
74 printf("stale ");
75 break;
76 case NUD_DELAY:
77 printf("delay ");
78 break;
79 case NUD_PROBE:
80 printf("probe ");
81 break;
82 case NUD_FAILED:
83 printf("failed ");
84 break;
85 case NUD_NOARP:
86 printf("noarp ");
87 break;
88 case NUD_PERMANENT:
89 printf("permanent ");
90 break;
91 default:
92 printf("%d ", ndm->ndm_state);
93 break;
94 }
95
96 printf("\n");
97 return MNL_CB_OK;
98 }
99
main(int argc,char * argv[])100 int main(int argc, char *argv[])
101 {
102 char buf[MNL_SOCKET_DUMP_SIZE];
103 unsigned int seq, portid;
104 struct mnl_socket *nl;
105 struct nlmsghdr *nlh;
106 struct ndmsg *nd;
107 int ret;
108
109 if (argc != 2) {
110 fprintf(stderr, "Usage: %s <inet|inet6>\n", argv[0]);
111 exit(EXIT_FAILURE);
112 }
113
114 nlh = mnl_nlmsg_put_header(buf);
115 nlh->nlmsg_type = RTM_GETNEIGH;
116 nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
117 nlh->nlmsg_seq = seq = time(NULL);
118
119 nd = mnl_nlmsg_put_extra_header(nlh, sizeof(struct ndmsg));
120 if (strcmp(argv[1], "inet") == 0)
121 nd->ndm_family = AF_INET;
122 else if (strcmp(argv[1], "inet6") == 0)
123 nd->ndm_family = AF_INET6;
124
125 nl = mnl_socket_open(NETLINK_ROUTE);
126 if (nl == NULL) {
127 perror("mnl_socket_open");
128 exit(EXIT_FAILURE);
129 }
130
131 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
132 perror("mnl_socket_bind");
133 exit(EXIT_FAILURE);
134 }
135 portid = mnl_socket_get_portid(nl);
136
137 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
138 perror("mnl_socket_sendto");
139 exit(EXIT_FAILURE);
140 }
141
142 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
143 while (ret > 0) {
144 ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
145 if (ret <= MNL_CB_STOP)
146 break;
147 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
148 }
149
150 if (ret == -1) {
151 perror("error");
152 exit(EXIT_FAILURE);
153 }
154
155 mnl_socket_close(nl);
156
157 return 0;
158 }
159