2 * a real quick'n'dirty hack to add/remove vcan interfaces.
3 * (also to have something to test the new RTNL API in vcan.)
4 * this will be added to ip(8) of the iproute package, making
7 * we don't check the return value of sendto() and don't wait for
8 * a reply using recvmsg(). We just hope everything works fine,
9 * otherwise use strace, or feel free to add the code before this
10 * whole thing is dumped to the bit bucket.
12 * Parts of this code were taken from the iproute source.
22 #include <sys/socket.h>
25 #include <asm/types.h>
26 #include <linux/netlink.h>
27 #include <linux/rtnetlink.h>
29 //#include <linux/if_link.h>
31 #define IFLA_LINKINFO 18
42 #define NLMSG_TAIL(nmsg) \
43 ((struct rtattr *)(((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
45 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
50 fprintf(stderr, "Usage: vcan create\n"
51 " vcan delete iface\n");
55 int main(int argc, char **argv)
64 struct sockaddr_nl nladdr;
65 struct rtattr *linkinfo;
68 fprintf(stderr, "This program is a temporary hack and is now obsolete.\n"
69 "Please use ip(8) instead, i.e.\n"
70 " ip link add type vcan or\n"
71 " ip link delete iface\n");
78 s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
80 memset(&req, 0, sizeof(req));
82 if (strcmp(cmd, "create") == 0) {
83 req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
84 req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
85 req.n.nlmsg_type = RTM_NEWLINK;
87 req.i.ifi_family = AF_UNSPEC;
89 linkinfo = NLMSG_TAIL(&req.n);
90 addattr_l(&req.n, sizeof(req), IFLA_LINKINFO, NULL, 0);
91 addattr_l(&req.n, sizeof(req), IFLA_INFO_NAME, "vcan", strlen("vcan"));
92 linkinfo->rta_len = (void*)NLMSG_TAIL(&req.n) - (void*)linkinfo;
94 } else if (strcmp(cmd, "delete") == 0) {
98 req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
99 req.n.nlmsg_flags = NLM_F_REQUEST;
100 req.n.nlmsg_type = RTM_DELLINK;
101 req.i.ifi_family = AF_UNSPEC;
102 req.i.ifi_index = if_nametoindex(dev);
106 memset(&nladdr, 0, sizeof(nladdr));
107 nladdr.nl_family = AF_NETLINK;
109 nladdr.nl_groups = 0;
111 sendto(s, &req, req.n.nlmsg_len, 0,
112 (struct sockaddr*)&nladdr, sizeof(nladdr));
117 for (i = 0; i < req.n.nlmsg_len; i++) {
118 printf(" %02x", ((unsigned char*)&req)[i]);
130 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
133 int len = RTA_LENGTH(alen);
136 if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
137 fprintf(stderr, "addattr_l ERROR: message exceeded bound of %d\n",
142 rta->rta_type = type;
144 memcpy(RTA_DATA(rta), data, alen);
145 n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);