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#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <malloc.h>
#include <errno.h>
#include <syslog.h>
#include <sys/socket.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/queue.h>
#define IF_RA_MANAGED 0x40
#define IF_RA_OTHERCONF 0x80
int main() {
int sd, status;
int seq = time(NULL);
struct sockaddr_nl nl_addr;
struct nlmsghdr *nlm_hdr;
struct rtgenmsg *rt_genmsg;
char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + NLMSG_ALIGN(sizeof(struct rtgenmsg))];
struct msghdr msgh;
struct nlmsghdr *nlm;
size_t newsize = 65536, size = 0;
int msg_len;
char *nbuf = NULL;
int nlm_len;
struct ifinfomsg *ifim;
struct rtattr *rta, *rta1;
size_t rtasize, rtapayload, rtasize1;
void *rtadata;
char if_name[10];
sd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sd < 0) {
perror("socket");
return -1;
}
memset(&nl_addr, 0, sizeof(nl_addr));
nl_addr.nl_family = AF_NETLINK;
if (bind(sd, (struct sockaddr *)&nl_addr, sizeof(nl_addr)) < 0) {
perror("bind");
return -1;
}
memset(&buf, 0, sizeof(buf));
nlm_hdr = (struct nlmsghdr *)buf;
nlm_hdr->nlmsg_len = NLMSG_LENGTH(sizeof(*rt_genmsg));
nlm_hdr->nlmsg_type = RTM_GETLINK;
nlm_hdr->nlmsg_flags = NLM_F_ROOT | NLM_F_REQUEST;
nlm_hdr->nlmsg_pid = getpid();
nlm_hdr->nlmsg_seq = seq;
memset(&nl_addr, 0, sizeof(nl_addr));
nl_addr.nl_family = AF_NETLINK;
rt_genmsg = (struct rtgenmsg *)NLMSG_DATA(nlm_hdr);
rt_genmsg->rtgen_family = AF_INET6;
status = sendto(sd, (void *)nlm_hdr, nlm_hdr->nlmsg_len, 0, (struct sockaddr *)&nl_addr, sizeof(nl_addr));
if (status < 0) {
perror("sendto");
return -1;
}
for (;;) {
void *newbuf = realloc(nbuf, newsize);
if (newbuf == NULL) {
perror("realloc");
return -1;
}
nbuf = newbuf;
/* If call intrupted do it again */
do {
struct iovec iov = {nbuf, newsize};
memset(&msgh, 0, sizeof(msgh));
msgh.msg_name = (void *)&nl_addr;
msgh.msg_namelen = sizeof(nl_addr);
msgh.msg_iov = &iov;
msgh.msg_iovlen = 1;
msg_len = recvmsg(sd, &msgh, 0);
}while (msg_len < 0 && errno == EINTR);
/* If msg truncated because of less size, call it with double the size */
if (msg_len < 0 || msgh.msg_flags & MSG_TRUNC) {
size = newsize;
newsize *= 2;
continue;
} else if (msg_len == 0)
break;
for (nlm = (struct nlmsghdr *)nbuf; NLMSG_OK(nlm, msg_len);
nlm = (struct nlmsghdr *)NLMSG_NEXT(nlm, msg_len)) {
if (nlm->nlmsg_type == NLMSG_DONE) {
printf("NLMSG_DONE\n");
return 0;
}
else if (nlm->nlmsg_type == NLMSG_ERROR) {
printf("NLMSG_ERROR\n");
return -1;
}
if (nlm->nlmsg_pid != getpid() || nlm->nlmsg_seq != seq)
continue;
ifim = (struct ifinfomsg *)NLMSG_DATA(nlm);
if (ifim->ifi_family != AF_INET6 || nlm->nlmsg_type != RTM_NEWLINK) {
printf("Not AF_INET6 or RTM_NEWLINK request\n");
return -1;
}
nlm_len = msg_len;
rtasize = NLMSG_PAYLOAD(nlm, nlm_len) - NLMSG_ALIGN(sizeof(*ifim));
for (rta = (struct rtattr *) (((char *) NLMSG_DATA(nlm)) +
NLMSG_ALIGN(sizeof(*ifim))); RTA_OK(rta, rtasize);
rta = RTA_NEXT(rta, rtasize)) {
rtadata = RTA_DATA(rta);
rtapayload = RTA_PAYLOAD(rta);
switch (rta->rta_type) {
case IFLA_PROTINFO:
rtasize1 = rta->rta_len;
for (rta1 = (struct rtattr *)rtadata; RTA_OK(rta1, rtasize1);
rta1 = RTA_NEXT(rta1, rtasize1)) {
void *rtadata1 = RTA_DATA(rta1);
switch(rta1->rta_type) {
case IFLA_INET6_FLAGS:
if_indextoname(ifim->ifi_index, if_name);
printf("interface: %s\n", if_name);
if (*((u_int32_t *)rtadata1) & IF_RA_MANAGED)
printf("\tmanaged flag is set\n");
else
printf("\tmanaged flag is not set\n");
if (*((u_int32_t *)rtadata1) & IF_RA_OTHERCONF)
printf("\tother flag is set\n");
else
printf("\tother flag is not set\n");
break;
}
}
break;
}
}
}
}
}
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