1 /* This example is placed in the public domain. */
2 #include <netinet/in.h>
3 #include <arpa/inet.h>
4 #include <time.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <strings.h>
9 #include <net/if.h>
10
11 #include <libmnl/libmnl.h>
12 #include <linux/if_link.h>
13 #include <linux/rtnetlink.h>
14
main(int argc,char * argv[])15 int main(int argc, char *argv[])
16 {
17 struct mnl_socket *nl;
18 char buf[MNL_SOCKET_BUFFER_SIZE];
19 struct nlmsghdr *nlh;
20 struct rtmsg *rtm;
21 uint32_t prefix, seq, portid;
22 union {
23 in_addr_t ip;
24 struct in6_addr ip6;
25 } dst;
26 union {
27 in_addr_t ip;
28 struct in6_addr ip6;
29 } gw;
30 int iface, ret, family = AF_INET;
31
32 if (argc <= 3) {
33 printf("Usage: %s iface destination cidr [gateway]\n", argv[0]);
34 printf("Example: %s eth0 10.0.1.12 32 10.0.1.11\n", argv[0]);
35 printf(" %s eth0 ffff::10.0.1.12 128 fdff::1\n", argv[0]);
36 exit(EXIT_FAILURE);
37 }
38
39 iface = if_nametoindex(argv[1]);
40 if (iface == 0) {
41 perror("if_nametoindex");
42 exit(EXIT_FAILURE);
43 }
44
45 if (!inet_pton(AF_INET, argv[2], &dst)) {
46 if (!inet_pton(AF_INET6, argv[2], &dst)) {
47 perror("inet_pton");
48 exit(EXIT_FAILURE);
49 }
50 family = AF_INET6;
51 }
52
53 if (sscanf(argv[3], "%u", &prefix) == 0) {
54 perror("sscanf");
55 exit(EXIT_FAILURE);
56 }
57
58 if (argc == 5 && !inet_pton(family, argv[4], &gw)) {
59 perror("inet_pton");
60 exit(EXIT_FAILURE);
61 }
62
63 nlh = mnl_nlmsg_put_header(buf);
64 nlh->nlmsg_type = RTM_NEWROUTE;
65 nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
66 nlh->nlmsg_seq = seq = time(NULL);
67
68 rtm = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtmsg));
69 rtm->rtm_family = family;
70 rtm->rtm_dst_len = prefix;
71 rtm->rtm_src_len = 0;
72 rtm->rtm_tos = 0;
73 rtm->rtm_protocol = RTPROT_STATIC;
74 rtm->rtm_table = RT_TABLE_MAIN;
75 rtm->rtm_type = RTN_UNICAST;
76 /* is there any gateway? */
77 rtm->rtm_scope = (argc == 4) ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
78 rtm->rtm_flags = 0;
79
80 if (family == AF_INET)
81 mnl_attr_put_u32(nlh, RTA_DST, dst.ip);
82 else
83 mnl_attr_put(nlh, RTA_DST, sizeof(struct in6_addr), &dst);
84
85 mnl_attr_put_u32(nlh, RTA_OIF, iface);
86 if (argc == 5) {
87 if (family == AF_INET)
88 mnl_attr_put_u32(nlh, RTA_GATEWAY, gw.ip);
89 else {
90 mnl_attr_put(nlh, RTA_GATEWAY, sizeof(struct in6_addr),
91 &gw.ip6);
92 }
93 }
94
95 nl = mnl_socket_open(NETLINK_ROUTE);
96 if (nl == NULL) {
97 perror("mnl_socket_open");
98 exit(EXIT_FAILURE);
99 }
100
101 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
102 perror("mnl_socket_bind");
103 exit(EXIT_FAILURE);
104 }
105 portid = mnl_socket_get_portid(nl);
106
107 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
108 perror("mnl_socket_sendto");
109 exit(EXIT_FAILURE);
110 }
111
112 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
113 if (ret < 0) {
114 perror("mnl_socket_recvfrom");
115 exit(EXIT_FAILURE);
116 }
117
118 ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);
119 if (ret < 0) {
120 perror("mnl_cb_run");
121 exit(EXIT_FAILURE);
122 }
123
124 mnl_socket_close(nl);
125
126 return 0;
127 }
128