3 * Linux INET6 implementation
6 * Pedro Roque <roque@di.fc.ul.pt>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #include <linux/capability.h>
15 #include <linux/errno.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/interrupt.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in6.h>
22 #include <linux/ipv6.h>
23 #include <linux/route.h>
24 #include <linux/slab.h>
27 #include <net/ndisc.h>
28 #include <net/addrconf.h>
29 #include <net/transp_v6.h>
30 #include <net/ip6_route.h>
31 #include <net/tcp_states.h>
33 #include <linux/errqueue.h>
34 #include <asm/uaccess.h>
36 static inline int ipv6_mapped_addr_any(const struct in6_addr *a)
38 return (ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0));
41 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
44 struct inet_sock *inet = inet_sk(sk);
45 struct ipv6_pinfo *np = inet6_sk(sk);
46 struct in6_addr *daddr, *final_p, final;
47 struct dst_entry *dst;
49 struct ip6_flowlabel *flowlabel = NULL;
50 struct ipv6_txoptions *opt;
54 if (usin->sin6_family == AF_INET) {
55 if (__ipv6_only_sock(sk))
57 err = ip4_datagram_connect(sk, uaddr, addr_len);
61 if (addr_len < SIN6_LEN_RFC2133)
64 if (usin->sin6_family != AF_INET6)
67 memset(&fl6, 0, sizeof(fl6));
69 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
70 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
71 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
72 if (flowlabel == NULL)
74 usin->sin6_addr = flowlabel->dst;
78 addr_type = ipv6_addr_type(&usin->sin6_addr);
80 if (addr_type == IPV6_ADDR_ANY) {
84 usin->sin6_addr.s6_addr[15] = 0x01;
87 daddr = &usin->sin6_addr;
89 if (addr_type == IPV6_ADDR_MAPPED) {
90 struct sockaddr_in sin;
92 if (__ipv6_only_sock(sk)) {
96 sin.sin_family = AF_INET;
97 sin.sin_addr.s_addr = daddr->s6_addr32[3];
98 sin.sin_port = usin->sin6_port;
100 err = ip4_datagram_connect(sk,
101 (struct sockaddr*) &sin,
108 ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
110 if (ipv6_addr_any(&np->saddr) ||
111 ipv6_mapped_addr_any(&np->saddr))
112 ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
114 if (ipv6_addr_any(&np->rcv_saddr) ||
115 ipv6_mapped_addr_any(&np->rcv_saddr)) {
116 ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
118 if (sk->sk_prot->rehash)
119 sk->sk_prot->rehash(sk);
125 if (addr_type&IPV6_ADDR_LINKLOCAL) {
126 if (addr_len >= sizeof(struct sockaddr_in6) &&
127 usin->sin6_scope_id) {
128 if (sk->sk_bound_dev_if &&
129 sk->sk_bound_dev_if != usin->sin6_scope_id) {
133 sk->sk_bound_dev_if = usin->sin6_scope_id;
136 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
137 sk->sk_bound_dev_if = np->mcast_oif;
139 /* Connect to link-local address requires an interface */
140 if (!sk->sk_bound_dev_if) {
147 np->flow_label = fl6.flowlabel;
149 inet->inet_dport = usin->sin6_port;
152 * Check for a route to destination an obtain the
153 * destination cache for it.
156 fl6.flowi6_proto = sk->sk_protocol;
157 fl6.daddr = np->daddr;
158 fl6.saddr = np->saddr;
159 fl6.flowi6_oif = sk->sk_bound_dev_if;
160 fl6.flowi6_mark = sk->sk_mark;
161 fl6.fl6_dport = inet->inet_dport;
162 fl6.fl6_sport = inet->inet_sport;
164 if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
165 fl6.flowi6_oif = np->mcast_oif;
167 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
169 opt = flowlabel ? flowlabel->opt : np->opt;
170 final_p = fl6_update_dst(&fl6, opt, &final);
172 dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
179 /* source address lookup done in ip6_dst_lookup */
181 if (ipv6_addr_any(&np->saddr))
182 np->saddr = fl6.saddr;
184 if (ipv6_addr_any(&np->rcv_saddr)) {
185 np->rcv_saddr = fl6.saddr;
186 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
187 if (sk->sk_prot->rehash)
188 sk->sk_prot->rehash(sk);
191 ip6_dst_store(sk, dst,
192 ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
194 #ifdef CONFIG_IPV6_SUBTREES
195 ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
200 sk->sk_state = TCP_ESTABLISHED;
202 fl6_sock_release(flowlabel);
206 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
207 __be16 port, u32 info, u8 *payload)
209 struct ipv6_pinfo *np = inet6_sk(sk);
210 struct icmp6hdr *icmph = icmp6_hdr(skb);
211 struct sock_exterr_skb *serr;
216 skb = skb_clone(skb, GFP_ATOMIC);
220 skb->protocol = htons(ETH_P_IPV6);
222 serr = SKB_EXT_ERR(skb);
223 serr->ee.ee_errno = err;
224 serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
225 serr->ee.ee_type = icmph->icmp6_type;
226 serr->ee.ee_code = icmph->icmp6_code;
228 serr->ee.ee_info = info;
229 serr->ee.ee_data = 0;
230 serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
231 skb_network_header(skb);
234 __skb_pull(skb, payload - skb->data);
235 skb_reset_transport_header(skb);
237 if (sock_queue_err_skb(sk, skb))
241 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
243 struct ipv6_pinfo *np = inet6_sk(sk);
244 struct sock_exterr_skb *serr;
251 skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
255 skb->protocol = htons(ETH_P_IPV6);
257 skb_put(skb, sizeof(struct ipv6hdr));
258 skb_reset_network_header(skb);
260 iph->daddr = fl6->daddr;
262 serr = SKB_EXT_ERR(skb);
263 serr->ee.ee_errno = err;
264 serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
265 serr->ee.ee_type = 0;
266 serr->ee.ee_code = 0;
268 serr->ee.ee_info = info;
269 serr->ee.ee_data = 0;
270 serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
271 serr->port = fl6->fl6_dport;
273 __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
274 skb_reset_transport_header(skb);
276 if (sock_queue_err_skb(sk, skb))
280 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
282 struct ipv6_pinfo *np = inet6_sk(sk);
285 struct ip6_mtuinfo *mtu_info;
287 if (!np->rxopt.bits.rxpmtu)
290 skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
294 skb_put(skb, sizeof(struct ipv6hdr));
295 skb_reset_network_header(skb);
297 iph->daddr = fl6->daddr;
299 mtu_info = IP6CBMTU(skb);
301 mtu_info->ip6m_mtu = mtu;
302 mtu_info->ip6m_addr.sin6_family = AF_INET6;
303 mtu_info->ip6m_addr.sin6_port = 0;
304 mtu_info->ip6m_addr.sin6_flowinfo = 0;
305 mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
306 mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
308 __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
309 skb_reset_transport_header(skb);
311 skb = xchg(&np->rxpmtu, skb);
316 * Handle MSG_ERRQUEUE
318 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
320 struct ipv6_pinfo *np = inet6_sk(sk);
321 struct sock_exterr_skb *serr;
322 struct sk_buff *skb, *skb2;
323 struct sockaddr_in6 *sin;
325 struct sock_extended_err ee;
326 struct sockaddr_in6 offender;
332 skb = skb_dequeue(&sk->sk_error_queue);
338 msg->msg_flags |= MSG_TRUNC;
341 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
345 sock_recv_timestamp(msg, sk, skb);
347 serr = SKB_EXT_ERR(skb);
349 sin = (struct sockaddr_in6 *)msg->msg_name;
351 const unsigned char *nh = skb_network_header(skb);
352 sin->sin6_family = AF_INET6;
353 sin->sin6_flowinfo = 0;
354 sin->sin6_port = serr->port;
355 sin->sin6_scope_id = 0;
356 if (skb->protocol == htons(ETH_P_IPV6)) {
358 *(struct in6_addr *)(nh + serr->addr_offset);
361 (*(__be32 *)(nh + serr->addr_offset - 24) &
363 if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
364 sin->sin6_scope_id = IP6CB(skb)->iif;
366 ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
371 memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
372 sin = &errhdr.offender;
373 sin->sin6_family = AF_UNSPEC;
374 if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
375 sin->sin6_family = AF_INET6;
376 sin->sin6_flowinfo = 0;
377 sin->sin6_scope_id = 0;
378 if (skb->protocol == htons(ETH_P_IPV6)) {
379 sin->sin6_addr = ipv6_hdr(skb)->saddr;
381 datagram_recv_ctl(sk, msg, skb);
382 if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
383 sin->sin6_scope_id = IP6CB(skb)->iif;
385 struct inet_sock *inet = inet_sk(sk);
387 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
389 if (inet->cmsg_flags)
390 ip_cmsg_recv(msg, skb);
394 put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
396 /* Now we could try to dump offended packet options */
398 msg->msg_flags |= MSG_ERRQUEUE;
401 /* Reset and regenerate socket error */
402 spin_lock_bh(&sk->sk_error_queue.lock);
404 if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
405 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
406 spin_unlock_bh(&sk->sk_error_queue.lock);
407 sk->sk_error_report(sk);
409 spin_unlock_bh(&sk->sk_error_queue.lock);
419 * Handle IPV6_RECVPATHMTU
421 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
423 struct ipv6_pinfo *np = inet6_sk(sk);
425 struct sockaddr_in6 *sin;
426 struct ip6_mtuinfo mtu_info;
431 skb = xchg(&np->rxpmtu, NULL);
437 msg->msg_flags |= MSG_TRUNC;
440 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
444 sock_recv_timestamp(msg, sk, skb);
446 memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
448 sin = (struct sockaddr_in6 *)msg->msg_name;
450 sin->sin6_family = AF_INET6;
451 sin->sin6_flowinfo = 0;
453 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
454 sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
457 put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
468 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
470 struct ipv6_pinfo *np = inet6_sk(sk);
471 struct inet6_skb_parm *opt = IP6CB(skb);
472 unsigned char *nh = skb_network_header(skb);
474 if (np->rxopt.bits.rxinfo) {
475 struct in6_pktinfo src_info;
477 src_info.ipi6_ifindex = opt->iif;
478 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
479 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
482 if (np->rxopt.bits.rxhlim) {
483 int hlim = ipv6_hdr(skb)->hop_limit;
484 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
487 if (np->rxopt.bits.rxtclass) {
488 int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
489 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
492 if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
493 __be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
494 put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
497 /* HbH is allowed only once */
498 if (np->rxopt.bits.hopopts && opt->hop) {
499 u8 *ptr = nh + opt->hop;
500 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
504 (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
506 * Silly enough, but we need to reparse in order to
507 * report extension headers (except for HbH)
510 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
511 * (and WILL NOT be) defined because
512 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
514 unsigned int off = sizeof(struct ipv6hdr);
515 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
517 while (off <= opt->lastopt) {
522 case IPPROTO_DSTOPTS:
524 len = (ptr[1] + 1) << 3;
525 if (np->rxopt.bits.dstopts)
526 put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
528 case IPPROTO_ROUTING:
530 len = (ptr[1] + 1) << 3;
531 if (np->rxopt.bits.srcrt)
532 put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
536 len = (ptr[1] + 2) << 2;
540 len = (ptr[1] + 1) << 3;
548 /* socket options in old style */
549 if (np->rxopt.bits.rxoinfo) {
550 struct in6_pktinfo src_info;
552 src_info.ipi6_ifindex = opt->iif;
553 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
554 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
556 if (np->rxopt.bits.rxohlim) {
557 int hlim = ipv6_hdr(skb)->hop_limit;
558 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
560 if (np->rxopt.bits.ohopopts && opt->hop) {
561 u8 *ptr = nh + opt->hop;
562 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
564 if (np->rxopt.bits.odstopts && opt->dst0) {
565 u8 *ptr = nh + opt->dst0;
566 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
568 if (np->rxopt.bits.osrcrt && opt->srcrt) {
569 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
570 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
572 if (np->rxopt.bits.odstopts && opt->dst1) {
573 u8 *ptr = nh + opt->dst1;
574 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
576 if (np->rxopt.bits.rxorigdstaddr) {
577 struct sockaddr_in6 sin6;
578 __be16 *ports = (__be16 *) skb_transport_header(skb);
580 if (skb_transport_offset(skb) + 4 <= skb->len) {
581 /* All current transport protocols have the port numbers in the
582 * first four bytes of the transport header and this function is
583 * written with this assumption in mind.
586 sin6.sin6_family = AF_INET6;
587 sin6.sin6_addr = ipv6_hdr(skb)->daddr;
588 sin6.sin6_port = ports[1];
589 sin6.sin6_flowinfo = 0;
590 sin6.sin6_scope_id = 0;
592 put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
598 int datagram_send_ctl(struct net *net, struct sock *sk,
599 struct msghdr *msg, struct flowi6 *fl6,
600 struct ipv6_txoptions *opt,
601 int *hlimit, int *tclass, int *dontfrag)
603 struct in6_pktinfo *src_info;
604 struct cmsghdr *cmsg;
605 struct ipv6_rt_hdr *rthdr;
606 struct ipv6_opt_hdr *hdr;
610 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
613 if (!CMSG_OK(msg, cmsg)) {
618 if (cmsg->cmsg_level != SOL_IPV6)
621 switch (cmsg->cmsg_type) {
623 case IPV6_2292PKTINFO:
625 struct net_device *dev = NULL;
627 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
632 src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
634 if (src_info->ipi6_ifindex) {
635 if (fl6->flowi6_oif &&
636 src_info->ipi6_ifindex != fl6->flowi6_oif)
638 fl6->flowi6_oif = src_info->ipi6_ifindex;
641 addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
644 if (fl6->flowi6_oif) {
645 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
650 } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
655 if (addr_type != IPV6_ADDR_ANY) {
656 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
657 if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
658 !ipv6_chk_addr(net, &src_info->ipi6_addr,
659 strict ? dev : NULL, 0))
662 fl6->saddr = src_info->ipi6_addr;
674 if (cmsg->cmsg_len < CMSG_LEN(4)) {
679 if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
680 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
685 fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
688 case IPV6_2292HOPOPTS:
690 if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
695 hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
696 len = ((hdr->hdrlen + 1) << 3);
697 if (cmsg->cmsg_len < CMSG_LEN(len)) {
701 if (!capable(CAP_NET_RAW)) {
705 opt->opt_nflen += len;
709 case IPV6_2292DSTOPTS:
710 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
715 hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
716 len = ((hdr->hdrlen + 1) << 3);
717 if (cmsg->cmsg_len < CMSG_LEN(len)) {
721 if (!capable(CAP_NET_RAW)) {
729 opt->opt_flen += len;
734 case IPV6_RTHDRDSTOPTS:
735 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
740 hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
741 len = ((hdr->hdrlen + 1) << 3);
742 if (cmsg->cmsg_len < CMSG_LEN(len)) {
746 if (!capable(CAP_NET_RAW)) {
750 if (cmsg->cmsg_type == IPV6_DSTOPTS) {
751 opt->opt_flen += len;
754 opt->opt_nflen += len;
761 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
766 rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
768 switch (rthdr->type) {
769 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
770 case IPV6_SRCRT_TYPE_2:
771 if (rthdr->hdrlen != 2 ||
772 rthdr->segments_left != 1) {
783 len = ((rthdr->hdrlen + 1) << 3);
785 if (cmsg->cmsg_len < CMSG_LEN(len)) {
790 /* segments left must also match */
791 if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
796 opt->opt_nflen += len;
799 if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
800 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
802 opt->opt_nflen += dsthdrlen;
803 opt->dst0opt = opt->dst1opt;
805 opt->opt_flen -= dsthdrlen;
810 case IPV6_2292HOPLIMIT:
812 if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
817 *hlimit = *(int *)CMSG_DATA(cmsg);
818 if (*hlimit < -1 || *hlimit > 0xff) {
830 if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
834 tc = *(int *)CMSG_DATA(cmsg);
835 if (tc < -1 || tc > 0xff)
849 if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
853 df = *(int *)CMSG_DATA(cmsg);
854 if (df < 0 || df > 1)
863 LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",