Commit message: ipv6: udp: fix the wrong headroom check

At this point, skb->data points to skb_transport_header.
So, headroom check is wrong.

For some case:bridge(UFO is on) + eth device(UFO is off),
there is no enough headroom for IPv6 frag head.
But headroom check is always false.

This will bring about data be moved to there prior to skb->head,
when adding IPv6 frag header to skb.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
CVE: CVE-2011-4326
CWE: CWE-399
Vulnerability description: The udp6_ufo_fragment function in net/ipv6/udp.c in the Linux kernel before 2.6.39, when a certain UDP Fragmentation Offload (UFO) configuration is enabled, allows remote attackers to cause a denial of service (system crash) by sending fragmented IPv6 UDP packets to a bridge device.

Project: linux
File: udp.c

void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		    u8 type, u8 code, int offset, __be32 info,
		    struct udp_table *udptable)
{
	struct ipv6_pinfo *np;
	struct ipv6hdr *hdr = (struct ipv6hdr*)skb->data;
	struct in6_addr *saddr = &hdr->saddr;
	struct in6_addr *daddr = &hdr->daddr;
	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
	struct sock *sk;
	int err;

	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
			       saddr, uh->source, inet6_iif(skb), udptable);
	if (sk == NULL)
		return;

	np = inet6_sk(sk);

	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
		goto out;

	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
		goto out;

	if (np->recverr)
		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));

	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

Project: linux
File: udp.c

static struct sock *__udp6_lib_lookup(struct net *net,
				      const struct in6_addr *saddr, __be16 sport,
				      const struct in6_addr *daddr, __be16 dport,
				      int dif, struct udp_table *udptable)
{
	struct sock *sk, *result;
	struct hlist_nulls_node *node;
	unsigned short hnum = ntohs(dport);
	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
	int score, badness;

	rcu_read_lock();
	if (hslot->count > 10) {
		hash2 = udp6_portaddr_hash(net, daddr, hnum);
		slot2 = hash2 & udptable->mask;
		hslot2 = &udptable->hash2[slot2];
		if (hslot->count < hslot2->count)
			goto begin;

		result = udp6_lib_lookup2(net, saddr, sport,
					  daddr, hnum, dif,
					  hslot2, slot2);
		if (!result) {
			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
			slot2 = hash2 & udptable->mask;
			hslot2 = &udptable->hash2[slot2];
			if (hslot->count < hslot2->count)
				goto begin;

			result = udp6_lib_lookup2(net, saddr, sport,
						  &in6addr_any, hnum, dif,
						  hslot2, slot2);
		}
		rcu_read_unlock();
		return result;
	}
begin:
	result = NULL;
	badness = -1;
	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
		if (score > badness) {
			result = sk;
			badness = score;
		}
	}
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (get_nulls_value(node) != slot)
		goto begin;

	if (result) {
		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
			result = NULL;
		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
					daddr, dport, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	rcu_read_unlock();
	return result;
}

Project: linux
File: udp.c

static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
		struct in6_addr *saddr, struct in6_addr *daddr,
		struct udp_table *udptable)
{
	struct sock *sk, *stack[256 / sizeof(struct sock *)];
	const struct udphdr *uh = udp_hdr(skb);
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
	int dif;
	unsigned int i, count = 0;

	spin_lock(&hslot->lock);
	sk = sk_nulls_head(&hslot->head);
	dif = inet6_iif(skb);
	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
	while (sk) {
		stack[count++] = sk;
		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
				       uh->source, saddr, dif);
		if (unlikely(count == ARRAY_SIZE(stack))) {
			if (!sk)
				break;
			flush_stack(stack, count, skb, ~0);
			count = 0;
		}
	}
	/*
	 * before releasing the lock, we must take reference on sockets
	 */
	for (i = 0; i < count; i++)
		sock_hold(stack[i]);

	spin_unlock(&hslot->lock);

	if (count) {
		flush_stack(stack, count, skb, count - 1);

		for (i = 0; i < count; i++)
			sock_put(stack[i]);
	} else {
		kfree_skb(skb);
	}
	return 0;
}

Project: linux
File: udp.c

int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
			    char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
}

Project: linux
File: udp.c

int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
			    char __user *optval, unsigned int optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_v6_push_pending_frames);
	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
}

Project: linux
File: udp.c

static inline int compute_score(struct sock *sk, struct net *net,
				unsigned short hnum,
				const struct in6_addr *saddr, __be16 sport,
				const struct in6_addr *daddr, __be16 dport,
				int dif)
{
	int score = -1;

	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
			sk->sk_family == PF_INET6) {
		struct ipv6_pinfo *np = inet6_sk(sk);
		struct inet_sock *inet = inet_sk(sk);

		score = 0;
		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
				return -1;
			score++;
		}
		if (!ipv6_addr_any(&np->rcv_saddr)) {
			if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
				return -1;
			score++;
		}
		if (!ipv6_addr_any(&np->daddr)) {
			if (!ipv6_addr_equal(&np->daddr, saddr))
				return -1;
			score++;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score++;
		}
	}
	return score;
}

Project: linux
File: udp.c

static inline int compute_score2(struct sock *sk, struct net *net,
				const struct in6_addr *saddr, __be16 sport,
				const struct in6_addr *daddr, unsigned short hnum,
				int dif)
{
	int score = -1;

	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
			sk->sk_family == PF_INET6) {
		struct ipv6_pinfo *np = inet6_sk(sk);
		struct inet_sock *inet = inet_sk(sk);

		if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
			return -1;
		score = 0;
		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
				return -1;
			score++;
		}
		if (!ipv6_addr_any(&np->daddr)) {
			if (!ipv6_addr_equal(&np->daddr, saddr))
				return -1;
			score++;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score++;
		}
	}
	return score;
}

Project: linux
File: udp.c

static void flush_stack(struct sock **stack, unsigned int count,
			struct sk_buff *skb, unsigned int final)
{
	unsigned int i;
	struct sock *sk;
	struct sk_buff *skb1;

	for (i = 0; i < count; i++) {
		skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);

		sk = stack[i];
		if (skb1) {
			if (sk_rcvqueues_full(sk, skb1)) {
				kfree_skb(skb1);
				goto drop;
			}
			bh_lock_sock(sk);
			if (!sock_owned_by_user(sk))
				udpv6_queue_rcv_skb(sk, skb1);
			else if (sk_add_backlog(sk, skb1)) {
				kfree_skb(skb1);
				bh_unlock_sock(sk);
				goto drop;
			}
			bh_unlock_sock(sk);
			continue;
		}
drop:
		atomic_inc(&sk->sk_drops);
		UDP6_INC_STATS_BH(sock_net(sk),
				UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
		UDP6_INC_STATS_BH(sock_net(sk),
				UDP_MIB_INERRORS, IS_UDPLITE(sk));
	}
}

Project: linux
File: udp.c

static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
				 int proto)
{
	int err;

	UDP_SKB_CB(skb)->partial_cov = 0;
	UDP_SKB_CB(skb)->cscov = skb->len;

	if (proto == IPPROTO_UDPLITE) {
		err = udplite_checksum_init(skb, uh);
		if (err)
			return err;
	}

	if (uh->check == 0) {
		/* RFC 2460 section 8.1 says that we SHOULD log
		   this error. Well, it is reasonable.
		 */
		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0\n");
		return 1;
	}
	if (skb->ip_summed == CHECKSUM_COMPLETE &&
	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
			     skb->len, proto, skb->csum))
		skb->ip_summed = CHECKSUM_UNNECESSARY;

	if (!skb_csum_unnecessary(skb))
		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
							 &ipv6_hdr(skb)->daddr,
							 skb->len, proto, 0));

	return 0;
}

Project: linux
File: udp.c

static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
				 const struct in6_addr *saddr,
				 const struct in6_addr *daddr, int len)
{
	unsigned int offset;
	struct udphdr *uh = udp_hdr(skb);
	__wsum csum = 0;

	if (skb_queue_len(&sk->sk_write_queue) == 1) {
		/* Only one fragment on the socket.  */
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
	} else {
		/*
		 * HW-checksum won't work as there are two or more
		 * fragments on the socket so that all csums of sk_buffs
		 * should be together
		 */
		offset = skb_transport_offset(skb);
		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);

		skb->ip_summed = CHECKSUM_NONE;

		skb_queue_walk(&sk->sk_write_queue, skb) {
			csum = csum_add(csum, skb->csum);
		}

		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
					    csum);
		if (uh->check == 0)
			uh->check = CSUM_MANGLED_0;
	}
}

Project: linux
File: udp.c

struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
			     const struct in6_addr *daddr, __be16 dport, int dif)
{
	return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
}

Project: linux
File: udp.c

static struct sock *udp6_lib_lookup2(struct net *net,
		const struct in6_addr *saddr, __be16 sport,
		const struct in6_addr *daddr, unsigned int hnum, int dif,
		struct udp_hslot *hslot2, unsigned int slot2)
{
	struct sock *sk, *result;
	struct hlist_nulls_node *node;
	int score, badness;

begin:
	result = NULL;
	badness = -1;
	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
		score = compute_score2(sk, net, saddr, sport,
				      daddr, hnum, dif);
		if (score > badness) {
			result = sk;
			badness = score;
			if (score == SCORE2_MAX)
				goto exact_match;
		}
	}
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (get_nulls_value(node) != slot2)
		goto begin;

	if (result) {
exact_match:
		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
			result = NULL;
		else if (unlikely(compute_score2(result, net, saddr, sport,
				  daddr, hnum, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	return result;
}

Project: linux
File: udp.c

static unsigned int udp6_portaddr_hash(struct net *net,
				       const struct in6_addr *addr6,
				       unsigned int port)
{
	unsigned int hash, mix = net_hash_mix(net);

	if (ipv6_addr_any(addr6))
		hash = jhash_1word(0, mix);
	else if (ipv6_addr_v4mapped(addr6))
		hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
	else
		hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);

	return hash ^ port;
}

Project: linux
File: udp.c

int __net_init udp6_proc_init(struct net *net)
{
	return udp_proc_register(net, &udp6_seq_afinfo);
}

Project: linux
File: udp.c

int udp6_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq,
			   "  sl  "
			   "local_address                         "
			   "remote_address                        "
			   "st tx_queue rx_queue tr tm->when retrnsmt"
			   "   uid  timeout inode ref pointer drops\n");
	else
		udp6_sock_seq_show(seq, v, ((struct udp_iter_state *)seq->private)->bucket);
	return 0;
}

Project: linux
File: udp.c

static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket)
{
	struct inet_sock *inet = inet_sk(sp);
	struct ipv6_pinfo *np = inet6_sk(sp);
	struct in6_addr *dest, *src;
	__u16 destp, srcp;

	dest  = &np->daddr;
	src   = &np->rcv_saddr;
	destp = ntohs(inet->inet_dport);
	srcp  = ntohs(inet->inet_sport);
	seq_printf(seq,
		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n",
		   bucket,
		   src->s6_addr32[0], src->s6_addr32[1],
		   src->s6_addr32[2], src->s6_addr32[3], srcp,
		   dest->s6_addr32[0], dest->s6_addr32[1],
		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
		   sp->sk_state,
		   sk_wmem_alloc_get(sp),
		   sk_rmem_alloc_get(sp),
		   0, 0L, 0,
		   sock_i_uid(sp), 0,
		   sock_i_ino(sp),
		   atomic_read(&sp->sk_refcnt), sp,
		   atomic_read(&sp->sk_drops));
}

Project: linux
File: udp.c

static int udp6_ufo_send_check(struct sk_buff *skb)
{
	struct ipv6hdr *ipv6h;
	struct udphdr *uh;

	if (!pskb_may_pull(skb, sizeof(*uh)))
		return -EINVAL;

	ipv6h = ipv6_hdr(skb);
	uh = udp_hdr(skb);

	uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
				     IPPROTO_UDP, 0);
	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct udphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;
	return 0;
}

Project: linux
File: udp.c

int udp_v6_get_port(struct sock *sk, unsigned short snum)
{
	unsigned int hash2_nulladdr =
		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
	unsigned int hash2_partial = 
		udp6_portaddr_hash(sock_net(sk), &inet6_sk(sk)->rcv_saddr, 0);

	/* precompute partial secondary hash */
	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
}

Project: linux
File: udp.c

static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
				      __be16 loc_port, struct in6_addr *loc_addr,
				      __be16 rmt_port, struct in6_addr *rmt_addr,
				      int dif)
{
	struct hlist_nulls_node *node;
	struct sock *s = sk;
	unsigned short num = ntohs(loc_port);

	sk_nulls_for_each_from(s, node) {
		struct inet_sock *inet = inet_sk(s);

		if (!net_eq(sock_net(s), net))
			continue;

		if (udp_sk(s)->udp_port_hash == num &&
		    s->sk_family == PF_INET6) {
			struct ipv6_pinfo *np = inet6_sk(s);
			if (inet->inet_dport) {
				if (inet->inet_dport != rmt_port)
					continue;
			}
			if (!ipv6_addr_any(&np->daddr) &&
			    !ipv6_addr_equal(&np->daddr, rmt_addr))
				continue;

			if (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)
				continue;

			if (!ipv6_addr_any(&np->rcv_saddr)) {
				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
					continue;
			}
			if (!inet6_mc_check(s, loc_addr, rmt_addr))
				continue;
			return s;
		}
	}
	return NULL;
}

Project: linux
File: udp.c

static void udp_v6_rehash(struct sock *sk)
{
	u16 new_hash = udp6_portaddr_hash(sock_net(sk),
					  &inet6_sk(sk)->rcv_saddr,
					  inet_sk(sk)->inet_num);

	udp_lib_rehash(sk, new_hash);
}

Project: linux
File: udp.c

void udpv6_destroy_sock(struct sock *sk)
{
	lock_sock(sk);
	udp_v6_flush_pending_frames(sk);
	release_sock(sk);

	inet6_destroy_sock(sk);
}

Project: linux
File: udp.c

void udpv6_exit(void)
{
	inet6_unregister_protosw(&udpv6_protosw);
	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
}

Project: linux
File: udp.c

int udpv6_getsockopt(struct sock *sk, int level, int optname,
		     char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return ipv6_getsockopt(sk, level, optname, optval, optlen);
}

Project: linux
File: udp.c

int __init udpv6_init(void)
{
	int ret;

	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
	if (ret)
		goto out;

	ret = inet6_register_protosw(&udpv6_protosw);
	if (ret)
		goto out_udpv6_protocol;
out:
	return ret;

out_udpv6_protocol:
	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
	goto out;
}

Project: linux
File: udp.c

int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
{
	struct udp_sock *up = udp_sk(sk);
	int rc;
	int is_udplite = IS_UDPLITE(sk);

	if (!ipv6_addr_any(&inet6_sk(sk)->daddr))
		sock_rps_save_rxhash(sk, skb->rxhash);

	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
		goto drop;

	/*
	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
	 */
	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {

		if (up->pcrlen == 0) {          /* full coverage was set  */
			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
				" %d while full coverage %d requested\n",
				UDP_SKB_CB(skb)->cscov, skb->len);
			goto drop;
		}
		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
						    "too small, need min %d\n",
				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
			goto drop;
		}
	}

	if (rcu_dereference_raw(sk->sk_filter)) {
		if (udp_lib_checksum_complete(skb))
			goto drop;
	}

	if ((rc = ip_queue_rcv_skb(sk, skb)) < 0) {
		/* Note that an ENOMEM error is charged twice */
		if (rc == -ENOMEM)
			UDP6_INC_STATS_BH(sock_net(sk),
					UDP_MIB_RCVBUFERRORS, is_udplite);
		goto drop_no_sk_drops_inc;
	}

	return 0;
drop:
	atomic_inc(&sk->sk_drops);
drop_no_sk_drops_inc:
	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
	kfree_skb(skb);
	return -1;
}

Project: linux
File: udp.c

static __inline__ int udpv6_rcv(struct sk_buff *skb)
{
	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
}

Project: linux
File: udp.c

int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
		  struct msghdr *msg, size_t len,
		  int noblock, int flags, int *addr_len)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct sk_buff *skb;
	unsigned int ulen;
	int peeked;
	int err;
	int is_udplite = IS_UDPLITE(sk);
	int is_udp4;
	bool slow;

	if (addr_len)
		*addr_len=sizeof(struct sockaddr_in6);

	if (flags & MSG_ERRQUEUE)
		return ipv6_recv_error(sk, msg, len);

	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
		return ipv6_recv_rxpmtu(sk, msg, len);

try_again:
	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
				  &peeked, &err);
	if (!skb)
		goto out;

	ulen = skb->len - sizeof(struct udphdr);
	if (len > ulen)
		len = ulen;
	else if (len < ulen)
		msg->msg_flags |= MSG_TRUNC;

	is_udp4 = (skb->protocol == htons(ETH_P_IP));

	/*
	 * If checksum is needed at all, try to do it while copying the
	 * data.  If the data is truncated, or if we only want a partial
	 * coverage checksum (UDP-Lite), do it before the copy.
	 */

	if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
					      msg->msg_iov,len);
	else {
		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
		if (err == -EINVAL)
			goto csum_copy_err;
	}
	if (err)
		goto out_free;

	if (!peeked) {
		if (is_udp4)
			UDP_INC_STATS_USER(sock_net(sk),
					UDP_MIB_INDATAGRAMS, is_udplite);
		else
			UDP6_INC_STATS_USER(sock_net(sk),
					UDP_MIB_INDATAGRAMS, is_udplite);
	}

	sock_recv_ts_and_drops(msg, sk, skb);

	/* Copy the address. */
	if (msg->msg_name) {
		struct sockaddr_in6 *sin6;

		sin6 = (struct sockaddr_in6 *) msg->msg_name;
		sin6->sin6_family = AF_INET6;
		sin6->sin6_port = udp_hdr(skb)->source;
		sin6->sin6_flowinfo = 0;
		sin6->sin6_scope_id = 0;

		if (is_udp4)
			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
					       &sin6->sin6_addr);
		else {
			ipv6_addr_copy(&sin6->sin6_addr,
				       &ipv6_hdr(skb)->saddr);
			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
				sin6->sin6_scope_id = IP6CB(skb)->iif;
		}

	}
	if (is_udp4) {
		if (inet->cmsg_flags)
			ip_cmsg_recv(msg, skb);
	} else {
		if (np->rxopt.all)
			datagram_recv_ctl(sk, msg, skb);
	}

	err = len;
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
	skb_free_datagram_locked(sk, skb);
out:
	return err;

csum_copy_err:
	slow = lock_sock_fast(sk);
	if (!skb_kill_datagram(sk, skb, flags)) {
		if (is_udp4)
			UDP_INC_STATS_USER(sock_net(sk),
					UDP_MIB_INERRORS, is_udplite);
		else
			UDP6_INC_STATS_USER(sock_net(sk),
					UDP_MIB_INERRORS, is_udplite);
	}
	unlock_sock_fast(sk, slow);

	if (flags & MSG_DONTWAIT)
		return -EAGAIN;
	goto try_again;
}

Project: linux
File: udp.c

int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
		  struct msghdr *msg, size_t len)
{
	struct ipv6_txoptions opt_space;
	struct udp_sock *up = udp_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
	struct in6_addr *daddr, *final_p, final;
	struct ipv6_txoptions *opt = NULL;
	struct ip6_flowlabel *flowlabel = NULL;
	struct flowi6 fl6;
	struct dst_entry *dst;
	int addr_len = msg->msg_namelen;
	int ulen = len;
	int hlimit = -1;
	int tclass = -1;
	int dontfrag = -1;
	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
	int err;
	int connected = 0;
	int is_udplite = IS_UDPLITE(sk);
	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);

	/* destination address check */
	if (sin6) {
		if (addr_len < offsetof(struct sockaddr, sa_data))
			return -EINVAL;

		switch (sin6->sin6_family) {
		case AF_INET6:
			if (addr_len < SIN6_LEN_RFC2133)
				return -EINVAL;
			daddr = &sin6->sin6_addr;
			break;
		case AF_INET:
			goto do_udp_sendmsg;
		case AF_UNSPEC:
			msg->msg_name = sin6 = NULL;
			msg->msg_namelen = addr_len = 0;
			daddr = NULL;
			break;
		default:
			return -EINVAL;
		}
	} else if (!up->pending) {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
		daddr = &np->daddr;
	} else
		daddr = NULL;

	if (daddr) {
		if (ipv6_addr_v4mapped(daddr)) {
			struct sockaddr_in sin;
			sin.sin_family = AF_INET;
			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
			sin.sin_addr.s_addr = daddr->s6_addr32[3];
			msg->msg_name = &sin;
			msg->msg_namelen = sizeof(sin);
do_udp_sendmsg:
			if (__ipv6_only_sock(sk))
				return -ENETUNREACH;
			return udp_sendmsg(iocb, sk, msg, len);
		}
	}

	if (up->pending == AF_INET)
		return udp_sendmsg(iocb, sk, msg, len);

	/* Rough check on arithmetic overflow,
	   better check is made in ip6_append_data().
	   */
	if (len > INT_MAX - sizeof(struct udphdr))
		return -EMSGSIZE;

	if (up->pending) {
		/*
		 * There are pending frames.
		 * The socket lock must be held while it's corked.
		 */
		lock_sock(sk);
		if (likely(up->pending)) {
			if (unlikely(up->pending != AF_INET6)) {
				release_sock(sk);
				return -EAFNOSUPPORT;
			}
			dst = NULL;
			goto do_append_data;
		}
		release_sock(sk);
	}
	ulen += sizeof(struct udphdr);

	memset(&fl6, 0, sizeof(fl6));

	if (sin6) {
		if (sin6->sin6_port == 0)
			return -EINVAL;

		fl6.fl6_dport = sin6->sin6_port;
		daddr = &sin6->sin6_addr;

		if (np->sndflow) {
			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
				if (flowlabel == NULL)
					return -EINVAL;
				daddr = &flowlabel->dst;
			}
		}

		/*
		 * Otherwise it will be difficult to maintain
		 * sk->sk_dst_cache.
		 */
		if (sk->sk_state == TCP_ESTABLISHED &&
		    ipv6_addr_equal(daddr, &np->daddr))
			daddr = &np->daddr;

		if (addr_len >= sizeof(struct sockaddr_in6) &&
		    sin6->sin6_scope_id &&
		    ipv6_addr_type(daddr)&IPV6_ADDR_LINKLOCAL)
			fl6.flowi6_oif = sin6->sin6_scope_id;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;

		fl6.fl6_dport = inet->inet_dport;
		daddr = &np->daddr;
		fl6.flowlabel = np->flow_label;
		connected = 1;
	}

	if (!fl6.flowi6_oif)
		fl6.flowi6_oif = sk->sk_bound_dev_if;

	if (!fl6.flowi6_oif)
		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;

	fl6.flowi6_mark = sk->sk_mark;

	if (msg->msg_controllen) {
		opt = &opt_space;
		memset(opt, 0, sizeof(struct ipv6_txoptions));
		opt->tot_len = sizeof(*opt);

		err = datagram_send_ctl(sock_net(sk), msg, &fl6, opt, &hlimit,
					&tclass, &dontfrag);
		if (err < 0) {
			fl6_sock_release(flowlabel);
			return err;
		}
		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
			if (flowlabel == NULL)
				return -EINVAL;
		}
		if (!(opt->opt_nflen|opt->opt_flen))
			opt = NULL;
		connected = 0;
	}
	if (opt == NULL)
		opt = np->opt;
	if (flowlabel)
		opt = fl6_merge_options(&opt_space, flowlabel, opt);
	opt = ipv6_fixup_options(&opt_space, opt);

	fl6.flowi6_proto = sk->sk_protocol;
	if (!ipv6_addr_any(daddr))
		ipv6_addr_copy(&fl6.daddr, daddr);
	else
		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
		ipv6_addr_copy(&fl6.saddr, &np->saddr);
	fl6.fl6_sport = inet->inet_sport;

	final_p = fl6_update_dst(&fl6, opt, &final);
	if (final_p)
		connected = 0;

	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
		fl6.flowi6_oif = np->mcast_oif;
		connected = 0;
	}

	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));

	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p, true);
	if (IS_ERR(dst)) {
		err = PTR_ERR(dst);
		dst = NULL;
		goto out;
	}

	if (hlimit < 0) {
		if (ipv6_addr_is_multicast(&fl6.daddr))
			hlimit = np->mcast_hops;
		else
			hlimit = np->hop_limit;
		if (hlimit < 0)
			hlimit = ip6_dst_hoplimit(dst);
	}

	if (tclass < 0)
		tclass = np->tclass;

	if (dontfrag < 0)
		dontfrag = np->dontfrag;

	if (msg->msg_flags&MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

	lock_sock(sk);
	if (unlikely(up->pending)) {
		/* The socket is already corked while preparing it. */
		/* ... which is an evident application bug. --ANK */
		release_sock(sk);

		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
		err = -EINVAL;
		goto out;
	}

	up->pending = AF_INET6;

do_append_data:
	up->len += ulen;
	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
		(struct rt6_info*)dst,
		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
	if (err)
		udp_v6_flush_pending_frames(sk);
	else if (!corkreq)
		err = udp_v6_push_pending_frames(sk);
	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
		up->pending = 0;

	if (dst) {
		if (connected) {
			ip6_dst_store(sk, dst,
				      ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
				      &np->daddr : NULL,
#ifdef CONFIG_IPV6_SUBTREES
				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
				      &np->saddr :
#endif
				      NULL);
		} else {
			dst_release(dst);
		}
		dst = NULL;
	}

	if (err > 0)
		err = np->recverr ? net_xmit_errno(err) : 0;
	release_sock(sk);
out:
	dst_release(dst);
	fl6_sock_release(flowlabel);
	if (!err)
		return len;
	/*
	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
	 * we don't have a good statistic (IpOutDiscards but it can be too many
	 * things).  We could add another new stat but at least for now that
	 * seems like overkill.
	 */
	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
		UDP6_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
	}
	return err;

do_confirm:
	dst_confirm(dst);
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}

Project: linux
File: udp.c

int udpv6_setsockopt(struct sock *sk, int level, int optname,
		     char __user *optval, unsigned int optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_v6_push_pending_frames);
	return ipv6_setsockopt(sk, level, optname, optval, optlen);
}