static int
rtadv_recv_packet (int sock, u_char *buf, int buflen,
struct sockaddr_in6 *from, unsigned int *ifindex,
int *hoplimit)
{
int ret;
struct msghdr msg;
struct iovec iov;
struct cmsghdr *cmsgptr;
struct in6_addr dst;
char adata[1024];
/* Fill in message and iovec. */
msg.msg_name = (void *) from;
msg.msg_namelen = sizeof (struct sockaddr_in6);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = (void *) adata;
msg.msg_controllen = sizeof adata;
iov.iov_base = buf;
iov.iov_len = buflen;
/* If recvmsg fail return minus value. */
ret = recvmsg (sock, &msg, 0);
if (ret < 0)
return ret;
for (cmsgptr = ZCMSG_FIRSTHDR(&msg); cmsgptr != NULL;
cmsgptr = CMSG_NXTHDR(&msg, cmsgptr))
{
/* I want interface index which this packet comes from. */
if (cmsgptr->cmsg_level == IPPROTO_IPV6 &&
cmsgptr->cmsg_type == IPV6_PKTINFO)
{
struct in6_pktinfo *ptr;
ptr = (struct in6_pktinfo *) CMSG_DATA (cmsgptr);
*ifindex = ptr->ipi6_ifindex;
memcpy(&dst, &ptr->ipi6_addr, sizeof(ptr->ipi6_addr));
}
/* Incoming packet's hop limit. */
if (cmsgptr->cmsg_level == IPPROTO_IPV6 &&
cmsgptr->cmsg_type == IPV6_HOPLIMIT)
{
int *hoptr = (int *) CMSG_DATA (cmsgptr);
*hoplimit = *hoptr;
}
}
return ret;
}
static void *
getsockopt_cmsg_data (struct msghdr *msgh, int level, int type)
{
struct cmsghdr *cmsg;
void *ptr = NULL;
for (cmsg = ZCMSG_FIRSTHDR(msgh);
cmsg != NULL;
cmsg = CMSG_NXTHDR(msgh, cmsg))
if (cmsg->cmsg_level == level && cmsg->cmsg_type)
return (ptr = CMSG_DATA(cmsg));
return NULL;
}
