1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *	IPv6 output functions
   4 *	Linux INET6 implementation
   5 *
   6 *	Authors:
   7 *	Pedro Roque		<roque@di.fc.ul.pt>
   8 *
   9 *	Based on linux/net/ipv4/ip_output.c
  10 *
 
 
 
 
 
  11 *	Changes:
  12 *	A.N.Kuznetsov	:	airthmetics in fragmentation.
  13 *				extension headers are implemented.
  14 *				route changes now work.
  15 *				ip6_forward does not confuse sniffers.
  16 *				etc.
  17 *
  18 *      H. von Brand    :       Added missing #include <linux/string.h>
  19 *	Imran Patel	:	frag id should be in NBO
  20 *      Kazunori MIYAZAWA @USAGI
  21 *			:       add ip6_append_data and related functions
  22 *				for datagram xmit
  23 */
  24
  25#include <linux/errno.h>
  26#include <linux/kernel.h>
  27#include <linux/string.h>
  28#include <linux/socket.h>
  29#include <linux/net.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_arp.h>
  32#include <linux/in6.h>
  33#include <linux/tcp.h>
  34#include <linux/route.h>
  35#include <linux/module.h>
  36#include <linux/slab.h>
  37
  38#include <linux/bpf-cgroup.h>
  39#include <linux/netfilter.h>
  40#include <linux/netfilter_ipv6.h>
  41
  42#include <net/sock.h>
  43#include <net/snmp.h>
  44
  45#include <net/gso.h>
  46#include <net/ipv6.h>
  47#include <net/ndisc.h>
  48#include <net/protocol.h>
  49#include <net/ip6_route.h>
  50#include <net/addrconf.h>
  51#include <net/rawv6.h>
  52#include <net/icmp.h>
  53#include <net/xfrm.h>
  54#include <net/checksum.h>
  55#include <linux/mroute6.h>
  56#include <net/l3mdev.h>
  57#include <net/lwtunnel.h>
  58#include <net/ip_tunnels.h>
  59
  60static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  61{
  62	struct dst_entry *dst = skb_dst(skb);
  63	struct net_device *dev = dst->dev;
  64	struct inet6_dev *idev = ip6_dst_idev(dst);
  65	unsigned int hh_len = LL_RESERVED_SPACE(dev);
  66	const struct in6_addr *daddr, *nexthop;
  67	struct ipv6hdr *hdr;
  68	struct neighbour *neigh;
  69	int ret;
  70
  71	/* Be paranoid, rather than too clever. */
  72	if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) {
  73		skb = skb_expand_head(skb, hh_len);
  74		if (!skb) {
  75			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
  76			return -ENOMEM;
  77		}
  78	}
  79
  80	hdr = ipv6_hdr(skb);
  81	daddr = &hdr->daddr;
  82	if (ipv6_addr_is_multicast(daddr)) {
  83		if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
  84		    ((mroute6_is_socket(net, skb) &&
  85		     !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
  86		     ipv6_chk_mcast_addr(dev, daddr, &hdr->saddr))) {
 
  87			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  88
  89			/* Do not check for IFF_ALLMULTI; multicast routing
  90			   is not supported in any case.
  91			 */
  92			if (newskb)
  93				NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  94					net, sk, newskb, NULL, newskb->dev,
  95					dev_loopback_xmit);
  96
  97			if (hdr->hop_limit == 0) {
  98				IP6_INC_STATS(net, idev,
  99					      IPSTATS_MIB_OUTDISCARDS);
 100				kfree_skb(skb);
 101				return 0;
 102			}
 103		}
 104
 105		IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
 106		if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL &&
 107		    !(dev->flags & IFF_LOOPBACK)) {
 108			kfree_skb(skb);
 109			return 0;
 110		}
 111	}
 112
 113	if (lwtunnel_xmit_redirect(dst->lwtstate)) {
 114		int res = lwtunnel_xmit(skb);
 115
 116		if (res != LWTUNNEL_XMIT_CONTINUE)
 117			return res;
 118	}
 119
 120	IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 121
 122	rcu_read_lock();
 123	nexthop = rt6_nexthop((struct rt6_info *)dst, daddr);
 124	neigh = __ipv6_neigh_lookup_noref(dev, nexthop);
 
 125
 126	if (unlikely(IS_ERR_OR_NULL(neigh))) {
 127		if (unlikely(!neigh))
 128			neigh = __neigh_create(&nd_tbl, nexthop, dev, false);
 129		if (IS_ERR(neigh)) {
 130			rcu_read_unlock();
 131			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
 132			kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
 133			return -EINVAL;
 134		}
 135	}
 136	sock_confirm_neigh(skb, neigh);
 137	ret = neigh_output(neigh, skb, false);
 138	rcu_read_unlock();
 139	return ret;
 140}
 141
 142static int
 143ip6_finish_output_gso_slowpath_drop(struct net *net, struct sock *sk,
 144				    struct sk_buff *skb, unsigned int mtu)
 145{
 146	struct sk_buff *segs, *nskb;
 147	netdev_features_t features;
 148	int ret = 0;
 149
 150	/* Please see corresponding comment in ip_finish_output_gso
 151	 * describing the cases where GSO segment length exceeds the
 152	 * egress MTU.
 153	 */
 154	features = netif_skb_features(skb);
 155	segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
 156	if (IS_ERR_OR_NULL(segs)) {
 157		kfree_skb(skb);
 158		return -ENOMEM;
 159	}
 160
 161	consume_skb(skb);
 162
 163	skb_list_walk_safe(segs, segs, nskb) {
 164		int err;
 165
 166		skb_mark_not_on_list(segs);
 167		/* Last GSO segment can be smaller than gso_size (and MTU).
 168		 * Adding a fragment header would produce an "atomic fragment",
 169		 * which is considered harmful (RFC-8021). Avoid that.
 170		 */
 171		err = segs->len > mtu ?
 172			ip6_fragment(net, sk, segs, ip6_finish_output2) :
 173			ip6_finish_output2(net, sk, segs);
 174		if (err && ret == 0)
 175			ret = err;
 176	}
 177
 178	return ret;
 179}
 180
 181static int ip6_finish_output_gso(struct net *net, struct sock *sk,
 182				 struct sk_buff *skb, unsigned int mtu)
 183{
 184	if (!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
 185	    !skb_gso_validate_network_len(skb, mtu))
 186		return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
 187
 188	return ip6_finish_output2(net, sk, skb);
 189}
 190
 191static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 192{
 193	unsigned int mtu;
 194
 195#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
 196	/* Policy lookup after SNAT yielded a new policy */
 197	if (skb_dst(skb)->xfrm) {
 198		IP6CB(skb)->flags |= IP6SKB_REROUTED;
 199		return dst_output(net, sk, skb);
 200	}
 201#endif
 202
 203	mtu = ip6_skb_dst_mtu(skb);
 204	if (skb_is_gso(skb))
 205		return ip6_finish_output_gso(net, sk, skb, mtu);
 206
 207	if (skb->len > mtu ||
 208	    (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 209		return ip6_fragment(net, sk, skb, ip6_finish_output2);
 210
 211	return ip6_finish_output2(net, sk, skb);
 212}
 213
 214static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 215{
 216	int ret;
 217
 218	ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
 219	switch (ret) {
 220	case NET_XMIT_SUCCESS:
 221	case NET_XMIT_CN:
 222		return __ip6_finish_output(net, sk, skb) ? : ret;
 223	default:
 224		kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
 225		return ret;
 226	}
 227}
 228
 229int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 230{
 231	struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
 232	struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 233
 234	skb->protocol = htons(ETH_P_IPV6);
 235	skb->dev = dev;
 236
 237	if (unlikely(idev->cnf.disable_ipv6)) {
 238		IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
 239		kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
 
 240		return 0;
 241	}
 242
 243	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
 244			    net, sk, skb, indev, dev,
 245			    ip6_finish_output,
 246			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 247}
 248EXPORT_SYMBOL(ip6_output);
 249
 250bool ip6_autoflowlabel(struct net *net, const struct sock *sk)
 251{
 252	if (!inet6_test_bit(AUTOFLOWLABEL_SET, sk))
 253		return ip6_default_np_autolabel(net);
 254	return inet6_test_bit(AUTOFLOWLABEL, sk);
 255}
 256
 257/*
 258 * xmit an sk_buff (used by TCP, SCTP and DCCP)
 259 * Note : socket lock is not held for SYNACK packets, but might be modified
 260 * by calls to skb_set_owner_w() and ipv6_local_error(),
 261 * which are using proper atomic operations or spinlocks.
 262 */
 263int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 264	     __u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority)
 
 265{
 266	struct net *net = sock_net(sk);
 267	const struct ipv6_pinfo *np = inet6_sk(sk);
 268	struct in6_addr *first_hop = &fl6->daddr;
 269	struct dst_entry *dst = skb_dst(skb);
 270	struct net_device *dev = dst->dev;
 271	struct inet6_dev *idev = ip6_dst_idev(dst);
 272	struct hop_jumbo_hdr *hop_jumbo;
 273	int hoplen = sizeof(*hop_jumbo);
 274	unsigned int head_room;
 275	struct ipv6hdr *hdr;
 276	u8  proto = fl6->flowi6_proto;
 277	int seg_len = skb->len;
 278	int hlimit = -1;
 279	u32 mtu;
 280
 281	head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
 282	if (opt)
 283		head_room += opt->opt_nflen + opt->opt_flen;
 284
 285	if (unlikely(head_room > skb_headroom(skb))) {
 286		skb = skb_expand_head(skb, head_room);
 287		if (!skb) {
 288			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
 289			return -ENOBUFS;
 290		}
 291	}
 292
 293	if (opt) {
 294		seg_len += opt->opt_nflen + opt->opt_flen;
 295
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 296		if (opt->opt_flen)
 297			ipv6_push_frag_opts(skb, opt, &proto);
 298
 299		if (opt->opt_nflen)
 300			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,
 301					     &fl6->saddr);
 302	}
 303
 304	if (unlikely(seg_len > IPV6_MAXPLEN)) {
 305		hop_jumbo = skb_push(skb, hoplen);
 306
 307		hop_jumbo->nexthdr = proto;
 308		hop_jumbo->hdrlen = 0;
 309		hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
 310		hop_jumbo->tlv_len = 4;
 311		hop_jumbo->jumbo_payload_len = htonl(seg_len + hoplen);
 312
 313		proto = IPPROTO_HOPOPTS;
 314		seg_len = 0;
 315		IP6CB(skb)->flags |= IP6SKB_FAKEJUMBO;
 316	}
 317
 318	skb_push(skb, sizeof(struct ipv6hdr));
 319	skb_reset_network_header(skb);
 320	hdr = ipv6_hdr(skb);
 321
 322	/*
 323	 *	Fill in the IPv6 header
 324	 */
 325	if (np)
 326		hlimit = READ_ONCE(np->hop_limit);
 327	if (hlimit < 0)
 328		hlimit = ip6_dst_hoplimit(dst);
 329
 330	ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
 331				ip6_autoflowlabel(net, sk), fl6));
 332
 333	hdr->payload_len = htons(seg_len);
 334	hdr->nexthdr = proto;
 335	hdr->hop_limit = hlimit;
 336
 337	hdr->saddr = fl6->saddr;
 338	hdr->daddr = *first_hop;
 339
 340	skb->protocol = htons(ETH_P_IPV6);
 341	skb->priority = priority;
 342	skb->mark = mark;
 343
 344	mtu = dst_mtu(dst);
 345	if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 346		IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
 347
 348		/* if egress device is enslaved to an L3 master device pass the
 349		 * skb to its handler for processing
 350		 */
 351		skb = l3mdev_ip6_out((struct sock *)sk, skb);
 352		if (unlikely(!skb))
 353			return 0;
 354
 355		/* hooks should never assume socket lock is held.
 356		 * we promote our socket to non const
 357		 */
 358		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 359			       net, (struct sock *)sk, skb, NULL, dev,
 360			       dst_output);
 361	}
 362
 363	skb->dev = dev;
 364	/* ipv6_local_error() does not require socket lock,
 365	 * we promote our socket to non const
 366	 */
 367	ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
 368
 369	IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
 370	kfree_skb(skb);
 371	return -EMSGSIZE;
 372}
 
 373EXPORT_SYMBOL(ip6_xmit);
 374
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 375static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 376{
 377	struct ip6_ra_chain *ra;
 378	struct sock *last = NULL;
 379
 380	read_lock(&ip6_ra_lock);
 381	for (ra = ip6_ra_chain; ra; ra = ra->next) {
 382		struct sock *sk = ra->sk;
 383		if (sk && ra->sel == sel &&
 384		    (!sk->sk_bound_dev_if ||
 385		     sk->sk_bound_dev_if == skb->dev->ifindex)) {
 386
 387			if (inet6_test_bit(RTALERT_ISOLATE, sk) &&
 388			    !net_eq(sock_net(sk), dev_net(skb->dev))) {
 389				continue;
 390			}
 391			if (last) {
 392				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 393				if (skb2)
 394					rawv6_rcv(last, skb2);
 395			}
 396			last = sk;
 397		}
 398	}
 399
 400	if (last) {
 401		rawv6_rcv(last, skb);
 402		read_unlock(&ip6_ra_lock);
 403		return 1;
 404	}
 405	read_unlock(&ip6_ra_lock);
 406	return 0;
 407}
 408
 409static int ip6_forward_proxy_check(struct sk_buff *skb)
 410{
 411	struct ipv6hdr *hdr = ipv6_hdr(skb);
 412	u8 nexthdr = hdr->nexthdr;
 413	__be16 frag_off;
 414	int offset;
 415
 416	if (ipv6_ext_hdr(nexthdr)) {
 417		offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 418		if (offset < 0)
 419			return 0;
 420	} else
 421		offset = sizeof(struct ipv6hdr);
 422
 423	if (nexthdr == IPPROTO_ICMPV6) {
 424		struct icmp6hdr *icmp6;
 425
 426		if (!pskb_may_pull(skb, (skb_network_header(skb) +
 427					 offset + 1 - skb->data)))
 428			return 0;
 429
 430		icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 431
 432		switch (icmp6->icmp6_type) {
 433		case NDISC_ROUTER_SOLICITATION:
 434		case NDISC_ROUTER_ADVERTISEMENT:
 435		case NDISC_NEIGHBOUR_SOLICITATION:
 436		case NDISC_NEIGHBOUR_ADVERTISEMENT:
 437		case NDISC_REDIRECT:
 438			/* For reaction involving unicast neighbor discovery
 439			 * message destined to the proxied address, pass it to
 440			 * input function.
 441			 */
 442			return 1;
 443		default:
 444			break;
 445		}
 446	}
 447
 448	/*
 449	 * The proxying router can't forward traffic sent to a link-local
 450	 * address, so signal the sender and discard the packet. This
 451	 * behavior is clarified by the MIPv6 specification.
 452	 */
 453	if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 454		dst_link_failure(skb);
 455		return -1;
 456	}
 457
 458	return 0;
 459}
 460
 461static inline int ip6_forward_finish(struct net *net, struct sock *sk,
 462				     struct sk_buff *skb)
 463{
 464#ifdef CONFIG_NET_SWITCHDEV
 465	if (skb->offload_l3_fwd_mark) {
 466		consume_skb(skb);
 467		return 0;
 468	}
 469#endif
 470
 471	skb_clear_tstamp(skb);
 472	return dst_output(net, sk, skb);
 473}
 474
 475static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 476{
 477	if (skb->len <= mtu)
 478		return false;
 479
 480	/* ipv6 conntrack defrag sets max_frag_size + ignore_df */
 481	if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
 482		return true;
 483
 484	if (skb->ignore_df)
 485		return false;
 486
 487	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 488		return false;
 489
 490	return true;
 491}
 492
 493int ip6_forward(struct sk_buff *skb)
 494{
 495	struct dst_entry *dst = skb_dst(skb);
 496	struct ipv6hdr *hdr = ipv6_hdr(skb);
 497	struct inet6_skb_parm *opt = IP6CB(skb);
 498	struct net *net = dev_net(dst->dev);
 499	struct inet6_dev *idev;
 500	SKB_DR(reason);
 501	u32 mtu;
 502
 503	idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
 504	if (net->ipv6.devconf_all->forwarding == 0)
 505		goto error;
 506
 507	if (skb->pkt_type != PACKET_HOST)
 508		goto drop;
 509
 510	if (unlikely(skb->sk))
 511		goto drop;
 512
 513	if (skb_warn_if_lro(skb))
 514		goto drop;
 515
 516	if (!net->ipv6.devconf_all->disable_policy &&
 517	    (!idev || !idev->cnf.disable_policy) &&
 518	    !xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 519		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 520		goto drop;
 521	}
 522
 
 
 
 523	skb_forward_csum(skb);
 524
 525	/*
 526	 *	We DO NOT make any processing on
 527	 *	RA packets, pushing them to user level AS IS
 528	 *	without ane WARRANTY that application will be able
 529	 *	to interpret them. The reason is that we
 530	 *	cannot make anything clever here.
 531	 *
 532	 *	We are not end-node, so that if packet contains
 533	 *	AH/ESP, we cannot make anything.
 534	 *	Defragmentation also would be mistake, RA packets
 535	 *	cannot be fragmented, because there is no warranty
 536	 *	that different fragments will go along one path. --ANK
 537	 */
 538	if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 539		if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 
 540			return 0;
 541	}
 542
 543	/*
 544	 *	check and decrement ttl
 545	 */
 546	if (hdr->hop_limit <= 1) {
 
 
 547		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 548		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 
 549
 550		kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
 551		return -ETIMEDOUT;
 552	}
 553
 554	/* XXX: idev->cnf.proxy_ndp? */
 555	if (net->ipv6.devconf_all->proxy_ndp &&
 556	    pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 557		int proxied = ip6_forward_proxy_check(skb);
 558		if (proxied > 0) {
 559			/* It's tempting to decrease the hop limit
 560			 * here by 1, as we do at the end of the
 561			 * function too.
 562			 *
 563			 * But that would be incorrect, as proxying is
 564			 * not forwarding.  The ip6_input function
 565			 * will handle this packet locally, and it
 566			 * depends on the hop limit being unchanged.
 567			 *
 568			 * One example is the NDP hop limit, that
 569			 * always has to stay 255, but other would be
 570			 * similar checks around RA packets, where the
 571			 * user can even change the desired limit.
 572			 */
 573			return ip6_input(skb);
 574		} else if (proxied < 0) {
 575			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 
 576			goto drop;
 577		}
 578	}
 579
 580	if (!xfrm6_route_forward(skb)) {
 581		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 582		SKB_DR_SET(reason, XFRM_POLICY);
 583		goto drop;
 584	}
 585	dst = skb_dst(skb);
 586
 587	/* IPv6 specs say nothing about it, but it is clear that we cannot
 588	   send redirects to source routed frames.
 589	   We don't send redirects to frames decapsulated from IPsec.
 590	 */
 591	if (IP6CB(skb)->iif == dst->dev->ifindex &&
 592	    opt->srcrt == 0 && !skb_sec_path(skb)) {
 593		struct in6_addr *target = NULL;
 594		struct inet_peer *peer;
 595		struct rt6_info *rt;
 596
 597		/*
 598		 *	incoming and outgoing devices are the same
 599		 *	send a redirect.
 600		 */
 601
 602		rt = (struct rt6_info *) dst;
 603		if (rt->rt6i_flags & RTF_GATEWAY)
 604			target = &rt->rt6i_gateway;
 605		else
 606			target = &hdr->daddr;
 607
 608		peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
 
 609
 610		/* Limit redirects both by destination (here)
 611		   and by source (inside ndisc_send_redirect)
 612		 */
 613		if (inet_peer_xrlim_allow(peer, 1*HZ))
 614			ndisc_send_redirect(skb, target);
 615		if (peer)
 616			inet_putpeer(peer);
 617	} else {
 618		int addrtype = ipv6_addr_type(&hdr->saddr);
 619
 620		/* This check is security critical. */
 621		if (addrtype == IPV6_ADDR_ANY ||
 622		    addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 623			goto error;
 624		if (addrtype & IPV6_ADDR_LINKLOCAL) {
 625			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 626				    ICMPV6_NOT_NEIGHBOUR, 0);
 627			goto error;
 628		}
 629	}
 630
 631	__IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 632
 633	mtu = ip6_dst_mtu_maybe_forward(dst, true);
 634	if (mtu < IPV6_MIN_MTU)
 635		mtu = IPV6_MIN_MTU;
 636
 637	if (ip6_pkt_too_big(skb, mtu)) {
 638		/* Again, force OUTPUT device used as source address */
 639		skb->dev = dst->dev;
 640		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 641		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
 642		__IP6_INC_STATS(net, ip6_dst_idev(dst),
 643				IPSTATS_MIB_FRAGFAILS);
 644		kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
 
 645		return -EMSGSIZE;
 646	}
 647
 648	if (skb_cow(skb, dst->dev->hard_header_len)) {
 649		__IP6_INC_STATS(net, ip6_dst_idev(dst),
 650				IPSTATS_MIB_OUTDISCARDS);
 651		goto drop;
 652	}
 653
 654	hdr = ipv6_hdr(skb);
 655
 656	/* Mangling hops number delayed to point after skb COW */
 657
 658	hdr->hop_limit--;
 659
 660	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
 661		       net, NULL, skb, skb->dev, dst->dev,
 
 662		       ip6_forward_finish);
 663
 664error:
 665	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 666	SKB_DR_SET(reason, IP_INADDRERRORS);
 667drop:
 668	kfree_skb_reason(skb, reason);
 669	return -EINVAL;
 670}
 671
 672static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 673{
 674	to->pkt_type = from->pkt_type;
 675	to->priority = from->priority;
 676	to->protocol = from->protocol;
 677	skb_dst_drop(to);
 678	skb_dst_set(to, dst_clone(skb_dst(from)));
 679	to->dev = from->dev;
 680	to->mark = from->mark;
 681
 682	skb_copy_hash(to, from);
 683
 684#ifdef CONFIG_NET_SCHED
 685	to->tc_index = from->tc_index;
 686#endif
 687	nf_copy(to, from);
 688	skb_ext_copy(to, from);
 
 
 
 689	skb_copy_secmark(to, from);
 690}
 691
 692int ip6_fraglist_init(struct sk_buff *skb, unsigned int hlen, u8 *prevhdr,
 693		      u8 nexthdr, __be32 frag_id,
 694		      struct ip6_fraglist_iter *iter)
 695{
 696	unsigned int first_len;
 697	struct frag_hdr *fh;
 
 
 
 
 698
 699	/* BUILD HEADER */
 700	*prevhdr = NEXTHDR_FRAGMENT;
 701	iter->tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 702	if (!iter->tmp_hdr)
 703		return -ENOMEM;
 704
 705	iter->frag = skb_shinfo(skb)->frag_list;
 706	skb_frag_list_init(skb);
 707
 708	iter->offset = 0;
 709	iter->hlen = hlen;
 710	iter->frag_id = frag_id;
 711	iter->nexthdr = nexthdr;
 712
 713	__skb_pull(skb, hlen);
 714	fh = __skb_push(skb, sizeof(struct frag_hdr));
 715	__skb_push(skb, hlen);
 716	skb_reset_network_header(skb);
 717	memcpy(skb_network_header(skb), iter->tmp_hdr, hlen);
 718
 719	fh->nexthdr = nexthdr;
 720	fh->reserved = 0;
 721	fh->frag_off = htons(IP6_MF);
 722	fh->identification = frag_id;
 723
 724	first_len = skb_pagelen(skb);
 725	skb->data_len = first_len - skb_headlen(skb);
 726	skb->len = first_len;
 727	ipv6_hdr(skb)->payload_len = htons(first_len - sizeof(struct ipv6hdr));
 728
 729	return 0;
 730}
 731EXPORT_SYMBOL(ip6_fraglist_init);
 732
 733void ip6_fraglist_prepare(struct sk_buff *skb,
 734			  struct ip6_fraglist_iter *iter)
 735{
 736	struct sk_buff *frag = iter->frag;
 737	unsigned int hlen = iter->hlen;
 738	struct frag_hdr *fh;
 
 
 
 
 
 
 739
 740	frag->ip_summed = CHECKSUM_NONE;
 741	skb_reset_transport_header(frag);
 742	fh = __skb_push(frag, sizeof(struct frag_hdr));
 743	__skb_push(frag, hlen);
 744	skb_reset_network_header(frag);
 745	memcpy(skb_network_header(frag), iter->tmp_hdr, hlen);
 746	iter->offset += skb->len - hlen - sizeof(struct frag_hdr);
 747	fh->nexthdr = iter->nexthdr;
 748	fh->reserved = 0;
 749	fh->frag_off = htons(iter->offset);
 750	if (frag->next)
 751		fh->frag_off |= htons(IP6_MF);
 752	fh->identification = iter->frag_id;
 753	ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
 754	ip6_copy_metadata(frag, skb);
 755}
 756EXPORT_SYMBOL(ip6_fraglist_prepare);
 757
 758void ip6_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int mtu,
 759		   unsigned short needed_tailroom, int hdr_room, u8 *prevhdr,
 760		   u8 nexthdr, __be32 frag_id, struct ip6_frag_state *state)
 761{
 762	state->prevhdr = prevhdr;
 763	state->nexthdr = nexthdr;
 764	state->frag_id = frag_id;
 765
 766	state->hlen = hlen;
 767	state->mtu = mtu;
 768
 769	state->left = skb->len - hlen;	/* Space per frame */
 770	state->ptr = hlen;		/* Where to start from */
 771
 772	state->hroom = hdr_room;
 773	state->troom = needed_tailroom;
 774
 775	state->offset = 0;
 776}
 777EXPORT_SYMBOL(ip6_frag_init);
 778
 779struct sk_buff *ip6_frag_next(struct sk_buff *skb, struct ip6_frag_state *state)
 780{
 781	u8 *prevhdr = state->prevhdr, *fragnexthdr_offset;
 782	struct sk_buff *frag;
 783	struct frag_hdr *fh;
 784	unsigned int len;
 785
 786	len = state->left;
 787	/* IF: it doesn't fit, use 'mtu' - the data space left */
 788	if (len > state->mtu)
 789		len = state->mtu;
 790	/* IF: we are not sending up to and including the packet end
 791	   then align the next start on an eight byte boundary */
 792	if (len < state->left)
 793		len &= ~7;
 794
 795	/* Allocate buffer */
 796	frag = alloc_skb(len + state->hlen + sizeof(struct frag_hdr) +
 797			 state->hroom + state->troom, GFP_ATOMIC);
 798	if (!frag)
 799		return ERR_PTR(-ENOMEM);
 800
 801	/*
 802	 *	Set up data on packet
 803	 */
 804
 805	ip6_copy_metadata(frag, skb);
 806	skb_reserve(frag, state->hroom);
 807	skb_put(frag, len + state->hlen + sizeof(struct frag_hdr));
 808	skb_reset_network_header(frag);
 809	fh = (struct frag_hdr *)(skb_network_header(frag) + state->hlen);
 810	frag->transport_header = (frag->network_header + state->hlen +
 811				  sizeof(struct frag_hdr));
 812
 813	/*
 814	 *	Charge the memory for the fragment to any owner
 815	 *	it might possess
 816	 */
 817	if (skb->sk)
 818		skb_set_owner_w(frag, skb->sk);
 819
 820	/*
 821	 *	Copy the packet header into the new buffer.
 822	 */
 823	skb_copy_from_linear_data(skb, skb_network_header(frag), state->hlen);
 824
 825	fragnexthdr_offset = skb_network_header(frag);
 826	fragnexthdr_offset += prevhdr - skb_network_header(skb);
 827	*fragnexthdr_offset = NEXTHDR_FRAGMENT;
 828
 829	/*
 830	 *	Build fragment header.
 831	 */
 832	fh->nexthdr = state->nexthdr;
 833	fh->reserved = 0;
 834	fh->identification = state->frag_id;
 835
 836	/*
 837	 *	Copy a block of the IP datagram.
 838	 */
 839	BUG_ON(skb_copy_bits(skb, state->ptr, skb_transport_header(frag),
 840			     len));
 841	state->left -= len;
 842
 843	fh->frag_off = htons(state->offset);
 844	if (state->left > 0)
 845		fh->frag_off |= htons(IP6_MF);
 846	ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
 847
 848	state->ptr += len;
 849	state->offset += len;
 850
 851	return frag;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 852}
 853EXPORT_SYMBOL(ip6_frag_next);
 854
 855int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 856		 int (*output)(struct net *, struct sock *, struct sk_buff *))
 857{
 858	struct sk_buff *frag;
 859	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 860	struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
 861				inet6_sk(skb->sk) : NULL;
 862	bool mono_delivery_time = skb->mono_delivery_time;
 863	struct ip6_frag_state state;
 864	unsigned int mtu, hlen, nexthdr_offset;
 865	ktime_t tstamp = skb->tstamp;
 866	int hroom, err = 0;
 867	__be32 frag_id;
 868	u8 *prevhdr, nexthdr = 0;
 
 869
 870	err = ip6_find_1stfragopt(skb, &prevhdr);
 871	if (err < 0)
 872		goto fail;
 873	hlen = err;
 874	nexthdr = *prevhdr;
 875	nexthdr_offset = prevhdr - skb_network_header(skb);
 876
 877	mtu = ip6_skb_dst_mtu(skb);
 878
 879	/* We must not fragment if the socket is set to force MTU discovery
 880	 * or if the skb it not generated by a local socket.
 881	 */
 882	if (unlikely(!skb->ignore_df && skb->len > mtu))
 883		goto fail_toobig;
 884
 885	if (IP6CB(skb)->frag_max_size) {
 886		if (IP6CB(skb)->frag_max_size > mtu)
 887			goto fail_toobig;
 888
 889		/* don't send fragments larger than what we received */
 890		mtu = IP6CB(skb)->frag_max_size;
 891		if (mtu < IPV6_MIN_MTU)
 892			mtu = IPV6_MIN_MTU;
 
 
 893	}
 894
 895	if (np) {
 896		u32 frag_size = READ_ONCE(np->frag_size);
 897
 898		if (frag_size && frag_size < mtu)
 899			mtu = frag_size;
 900	}
 901	if (mtu < hlen + sizeof(struct frag_hdr) + 8)
 902		goto fail_toobig;
 903	mtu -= hlen + sizeof(struct frag_hdr);
 904
 905	frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
 906				    &ipv6_hdr(skb)->saddr);
 907
 908	if (skb->ip_summed == CHECKSUM_PARTIAL &&
 909	    (err = skb_checksum_help(skb)))
 910		goto fail;
 911
 912	prevhdr = skb_network_header(skb) + nexthdr_offset;
 913	hroom = LL_RESERVED_SPACE(rt->dst.dev);
 914	if (skb_has_frag_list(skb)) {
 915		unsigned int first_len = skb_pagelen(skb);
 916		struct ip6_fraglist_iter iter;
 917		struct sk_buff *frag2;
 918
 919		if (first_len - hlen > mtu ||
 920		    ((first_len - hlen) & 7) ||
 921		    skb_cloned(skb) ||
 922		    skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
 923			goto slow_path;
 924
 925		skb_walk_frags(skb, frag) {
 926			/* Correct geometry. */
 927			if (frag->len > mtu ||
 928			    ((frag->len & 7) && frag->next) ||
 929			    skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
 930				goto slow_path_clean;
 931
 932			/* Partially cloned skb? */
 933			if (skb_shared(frag))
 934				goto slow_path_clean;
 935
 936			BUG_ON(frag->sk);
 937			if (skb->sk) {
 938				frag->sk = skb->sk;
 939				frag->destructor = sock_wfree;
 940			}
 941			skb->truesize -= frag->truesize;
 942		}
 943
 944		err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
 945					&iter);
 946		if (err < 0)
 947			goto fail;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 948
 949		/* We prevent @rt from being freed. */
 950		rcu_read_lock();
 951
 952		for (;;) {
 953			/* Prepare header of the next frame,
 954			 * before previous one went down. */
 955			if (iter.frag)
 956				ip6_fraglist_prepare(skb, &iter);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 957
 958			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
 959			err = output(net, sk, skb);
 960			if (!err)
 961				IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 962					      IPSTATS_MIB_FRAGCREATES);
 963
 964			if (err || !iter.frag)
 965				break;
 966
 967			skb = ip6_fraglist_next(&iter);
 
 
 968		}
 969
 970		kfree(iter.tmp_hdr);
 971
 972		if (err == 0) {
 973			IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 974				      IPSTATS_MIB_FRAGOKS);
 975			rcu_read_unlock();
 976			return 0;
 977		}
 978
 979		kfree_skb_list(iter.frag);
 
 
 
 
 980
 981		IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 982			      IPSTATS_MIB_FRAGFAILS);
 983		rcu_read_unlock();
 984		return err;
 985
 986slow_path_clean:
 987		skb_walk_frags(skb, frag2) {
 988			if (frag2 == frag)
 989				break;
 990			frag2->sk = NULL;
 991			frag2->destructor = NULL;
 992			skb->truesize += frag2->truesize;
 993		}
 994	}
 995
 996slow_path:
 
 
 
 
 
 
 
 997	/*
 998	 *	Fragment the datagram.
 999	 */
1000
1001	ip6_frag_init(skb, hlen, mtu, rt->dst.dev->needed_tailroom,
1002		      LL_RESERVED_SPACE(rt->dst.dev), prevhdr, nexthdr, frag_id,
1003		      &state);
1004
1005	/*
1006	 *	Keep copying data until we run out.
1007	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
1008
1009	while (state.left > 0) {
1010		frag = ip6_frag_next(skb, &state);
1011		if (IS_ERR(frag)) {
1012			err = PTR_ERR(frag);
 
 
1013			goto fail;
1014		}
1015
1016		/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1017		 *	Put this fragment into the sending queue.
1018		 */
1019		skb_set_delivery_time(frag, tstamp, mono_delivery_time);
1020		err = output(net, sk, frag);
1021		if (err)
1022			goto fail;
1023
1024		IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1025			      IPSTATS_MIB_FRAGCREATES);
1026	}
1027	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1028		      IPSTATS_MIB_FRAGOKS);
1029	consume_skb(skb);
1030	return err;
1031
1032fail_toobig:
1033	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1034	err = -EMSGSIZE;
1035
1036fail:
1037	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1038		      IPSTATS_MIB_FRAGFAILS);
1039	kfree_skb(skb);
1040	return err;
1041}
1042
1043static inline int ip6_rt_check(const struct rt6key *rt_key,
1044			       const struct in6_addr *fl_addr,
1045			       const struct in6_addr *addr_cache)
1046{
1047	return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
1048		(!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
1049}
1050
1051static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
1052					  struct dst_entry *dst,
1053					  const struct flowi6 *fl6)
1054{
1055	struct ipv6_pinfo *np = inet6_sk(sk);
1056	struct rt6_info *rt;
1057
1058	if (!dst)
1059		goto out;
1060
1061	if (dst->ops->family != AF_INET6) {
1062		dst_release(dst);
1063		return NULL;
1064	}
1065
1066	rt = (struct rt6_info *)dst;
1067	/* Yes, checking route validity in not connected
1068	 * case is not very simple. Take into account,
1069	 * that we do not support routing by source, TOS,
1070	 * and MSG_DONTROUTE		--ANK (980726)
1071	 *
1072	 * 1. ip6_rt_check(): If route was host route,
1073	 *    check that cached destination is current.
1074	 *    If it is network route, we still may
1075	 *    check its validity using saved pointer
1076	 *    to the last used address: daddr_cache.
1077	 *    We do not want to save whole address now,
1078	 *    (because main consumer of this service
1079	 *    is tcp, which has not this problem),
1080	 *    so that the last trick works only on connected
1081	 *    sockets.
1082	 * 2. oif also should be the same.
1083	 */
1084	if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
1085#ifdef CONFIG_IPV6_SUBTREES
1086	    ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
1087#endif
1088	   (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
1089		dst_release(dst);
1090		dst = NULL;
1091	}
1092
1093out:
1094	return dst;
1095}
1096
1097static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
1098			       struct dst_entry **dst, struct flowi6 *fl6)
1099{
 
1100#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
1101	struct neighbour *n;
1102	struct rt6_info *rt;
1103#endif
1104	int err;
1105	int flags = 0;
1106
1107	/* The correct way to handle this would be to do
1108	 * ip6_route_get_saddr, and then ip6_route_output; however,
1109	 * the route-specific preferred source forces the
1110	 * ip6_route_output call _before_ ip6_route_get_saddr.
1111	 *
1112	 * In source specific routing (no src=any default route),
1113	 * ip6_route_output will fail given src=any saddr, though, so
1114	 * that's why we try it again later.
1115	 */
1116	if (ipv6_addr_any(&fl6->saddr)) {
1117		struct fib6_info *from;
1118		struct rt6_info *rt;
1119
 
1120		*dst = ip6_route_output(net, sk, fl6);
1121		rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
1122
1123		rcu_read_lock();
1124		from = rt ? rcu_dereference(rt->from) : NULL;
1125		err = ip6_route_get_saddr(net, from, &fl6->daddr,
1126					  sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0,
1127					  &fl6->saddr);
1128		rcu_read_unlock();
1129
 
 
 
 
 
1130		if (err)
1131			goto out_err_release;
1132
1133		/* If we had an erroneous initial result, pretend it
1134		 * never existed and let the SA-enabled version take
1135		 * over.
1136		 */
1137		if ((*dst)->error) {
1138			dst_release(*dst);
1139			*dst = NULL;
1140		}
1141
1142		if (fl6->flowi6_oif)
1143			flags |= RT6_LOOKUP_F_IFACE;
1144	}
1145
1146	if (!*dst)
1147		*dst = ip6_route_output_flags(net, sk, fl6, flags);
1148
1149	err = (*dst)->error;
1150	if (err)
1151		goto out_err_release;
1152
1153#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
1154	/*
1155	 * Here if the dst entry we've looked up
1156	 * has a neighbour entry that is in the INCOMPLETE
1157	 * state and the src address from the flow is
1158	 * marked as OPTIMISTIC, we release the found
1159	 * dst entry and replace it instead with the
1160	 * dst entry of the nexthop router
1161	 */
1162	rt = (struct rt6_info *) *dst;
1163	rcu_read_lock();
1164	n = __ipv6_neigh_lookup_noref(rt->dst.dev,
1165				      rt6_nexthop(rt, &fl6->daddr));
1166	err = n && !(READ_ONCE(n->nud_state) & NUD_VALID) ? -EINVAL : 0;
1167	rcu_read_unlock();
1168
1169	if (err) {
1170		struct inet6_ifaddr *ifp;
1171		struct flowi6 fl_gw6;
1172		int redirect;
1173
 
1174		ifp = ipv6_get_ifaddr(net, &fl6->saddr,
1175				      (*dst)->dev, 1);
1176
1177		redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
1178		if (ifp)
1179			in6_ifa_put(ifp);
1180
1181		if (redirect) {
1182			/*
1183			 * We need to get the dst entry for the
1184			 * default router instead
1185			 */
1186			dst_release(*dst);
1187			memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1188			memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1189			*dst = ip6_route_output(net, sk, &fl_gw6);
1190			err = (*dst)->error;
1191			if (err)
1192				goto out_err_release;
1193		}
 
 
1194	}
1195#endif
1196	if (ipv6_addr_v4mapped(&fl6->saddr) &&
1197	    !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
1198		err = -EAFNOSUPPORT;
1199		goto out_err_release;
1200	}
1201
1202	return 0;
1203
1204out_err_release:
 
 
1205	dst_release(*dst);
1206	*dst = NULL;
1207
1208	if (err == -ENETUNREACH)
1209		IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1210	return err;
1211}
1212
1213/**
1214 *	ip6_dst_lookup - perform route lookup on flow
1215 *	@net: Network namespace to perform lookup in
1216 *	@sk: socket which provides route info
1217 *	@dst: pointer to dst_entry * for result
1218 *	@fl6: flow to lookup
1219 *
1220 *	This function performs a route lookup on the given flow.
1221 *
1222 *	It returns zero on success, or a standard errno code on error.
1223 */
1224int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1225		   struct flowi6 *fl6)
1226{
1227	*dst = NULL;
1228	return ip6_dst_lookup_tail(net, sk, dst, fl6);
1229}
1230EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1231
1232/**
1233 *	ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1234 *	@net: Network namespace to perform lookup in
1235 *	@sk: socket which provides route info
1236 *	@fl6: flow to lookup
1237 *	@final_dst: final destination address for ipsec lookup
 
1238 *
1239 *	This function performs a route lookup on the given flow.
1240 *
1241 *	It returns a valid dst pointer on success, or a pointer encoded
1242 *	error code.
1243 */
1244struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
1245				      const struct in6_addr *final_dst)
 
1246{
1247	struct dst_entry *dst = NULL;
1248	int err;
1249
1250	err = ip6_dst_lookup_tail(net, sk, &dst, fl6);
1251	if (err)
1252		return ERR_PTR(err);
1253	if (final_dst)
1254		fl6->daddr = *final_dst;
 
 
1255
1256	return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0);
1257}
1258EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1259
1260/**
1261 *	ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1262 *	@sk: socket which provides the dst cache and route info
1263 *	@fl6: flow to lookup
1264 *	@final_dst: final destination address for ipsec lookup
1265 *	@connected: whether @sk is connected or not
1266 *
1267 *	This function performs a route lookup on the given flow with the
1268 *	possibility of using the cached route in the socket if it is valid.
1269 *	It will take the socket dst lock when operating on the dst cache.
1270 *	As a result, this function can only be used in process context.
1271 *
1272 *	In addition, for a connected socket, cache the dst in the socket
1273 *	if the current cache is not valid.
1274 *
1275 *	It returns a valid dst pointer on success, or a pointer encoded
1276 *	error code.
1277 */
1278struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1279					 const struct in6_addr *final_dst,
1280					 bool connected)
1281{
1282	struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
 
1283
1284	dst = ip6_sk_dst_check(sk, dst, fl6);
1285	if (dst)
1286		return dst;
1287
1288	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst);
1289	if (connected && !IS_ERR(dst))
1290		ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6);
 
 
 
 
1291
1292	return dst;
1293}
1294EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1295
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1296static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1297					       gfp_t gfp)
1298{
1299	return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1300}
1301
1302static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1303						gfp_t gfp)
1304{
1305	return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1306}
1307
1308static void ip6_append_data_mtu(unsigned int *mtu,
1309				int *maxfraglen,
1310				unsigned int fragheaderlen,
1311				struct sk_buff *skb,
1312				struct rt6_info *rt,
1313				unsigned int orig_mtu)
1314{
1315	if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1316		if (!skb) {
1317			/* first fragment, reserve header_len */
1318			*mtu = orig_mtu - rt->dst.header_len;
1319
1320		} else {
1321			/*
1322			 * this fragment is not first, the headers
1323			 * space is regarded as data space.
1324			 */
1325			*mtu = orig_mtu;
1326		}
1327		*maxfraglen = ((*mtu - fragheaderlen) & ~7)
1328			      + fragheaderlen - sizeof(struct frag_hdr);
1329	}
1330}
1331
1332static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1333			  struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1334			  struct rt6_info *rt)
 
 
1335{
 
1336	struct ipv6_pinfo *np = inet6_sk(sk);
1337	unsigned int mtu, frag_size;
1338	struct ipv6_txoptions *nopt, *opt = ipc6->opt;
1339
1340	/* callers pass dst together with a reference, set it first so
1341	 * ip6_cork_release() can put it down even in case of an error.
1342	 */
1343	cork->base.dst = &rt->dst;
1344
1345	/*
1346	 * setup for corking
1347	 */
1348	if (opt) {
1349		if (WARN_ON(v6_cork->opt))
1350			return -EINVAL;
1351
1352		nopt = v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation);
1353		if (unlikely(!nopt))
1354			return -ENOBUFS;
1355
1356		nopt->tot_len = sizeof(*opt);
1357		nopt->opt_flen = opt->opt_flen;
1358		nopt->opt_nflen = opt->opt_nflen;
1359
1360		nopt->dst0opt = ip6_opt_dup(opt->dst0opt, sk->sk_allocation);
1361		if (opt->dst0opt && !nopt->dst0opt)
1362			return -ENOBUFS;
1363
1364		nopt->dst1opt = ip6_opt_dup(opt->dst1opt, sk->sk_allocation);
1365		if (opt->dst1opt && !nopt->dst1opt)
1366			return -ENOBUFS;
1367
1368		nopt->hopopt = ip6_opt_dup(opt->hopopt, sk->sk_allocation);
1369		if (opt->hopopt && !nopt->hopopt)
1370			return -ENOBUFS;
1371
1372		nopt->srcrt = ip6_rthdr_dup(opt->srcrt, sk->sk_allocation);
1373		if (opt->srcrt && !nopt->srcrt)
1374			return -ENOBUFS;
1375
1376		/* need source address above miyazawa*/
1377	}
1378	v6_cork->hop_limit = ipc6->hlimit;
1379	v6_cork->tclass = ipc6->tclass;
1380	if (rt->dst.flags & DST_XFRM_TUNNEL)
1381		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1382		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
1383	else
1384		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1385			READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
1386
1387	frag_size = READ_ONCE(np->frag_size);
1388	if (frag_size && frag_size < mtu)
1389		mtu = frag_size;
1390
1391	cork->base.fragsize = mtu;
1392	cork->base.gso_size = ipc6->gso_size;
1393	cork->base.tx_flags = 0;
1394	cork->base.mark = ipc6->sockc.mark;
1395	sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags);
1396
1397	cork->base.length = 0;
1398	cork->base.transmit_time = ipc6->sockc.transmit_time;
1399
1400	return 0;
1401}
1402
1403static int __ip6_append_data(struct sock *sk,
1404			     struct sk_buff_head *queue,
1405			     struct inet_cork_full *cork_full,
1406			     struct inet6_cork *v6_cork,
1407			     struct page_frag *pfrag,
1408			     int getfrag(void *from, char *to, int offset,
1409					 int len, int odd, struct sk_buff *skb),
1410			     void *from, size_t length, int transhdrlen,
1411			     unsigned int flags, struct ipcm6_cookie *ipc6)
1412{
1413	struct sk_buff *skb, *skb_prev = NULL;
1414	struct inet_cork *cork = &cork_full->base;
1415	struct flowi6 *fl6 = &cork_full->fl.u.ip6;
1416	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
1417	struct ubuf_info *uarg = NULL;
1418	int exthdrlen = 0;
1419	int dst_exthdrlen = 0;
1420	int hh_len;
 
1421	int copy;
1422	int err;
1423	int offset = 0;
1424	bool zc = false;
1425	u32 tskey = 0;
1426	struct rt6_info *rt = (struct rt6_info *)cork->dst;
1427	bool paged, hold_tskey, extra_uref = false;
1428	struct ipv6_txoptions *opt = v6_cork->opt;
1429	int csummode = CHECKSUM_NONE;
1430	unsigned int maxnonfragsize, headersize;
1431	unsigned int wmem_alloc_delta = 0;
1432
1433	skb = skb_peek_tail(queue);
1434	if (!skb) {
1435		exthdrlen = opt ? opt->opt_flen : 0;
1436		dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1437	}
1438
1439	paged = !!cork->gso_size;
1440	mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
1441	orig_mtu = mtu;
1442
1443	hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1444
1445	fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1446			(opt ? opt->opt_nflen : 0);
 
 
 
 
 
 
1447
1448	headersize = sizeof(struct ipv6hdr) +
1449		     (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1450		     rt->rt6i_nfheader_len;
1451
1452	if (mtu <= fragheaderlen ||
1453	    ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
1454		goto emsgsize;
1455
1456	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1457		     sizeof(struct frag_hdr);
 
 
 
 
 
 
1458
1459	/* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit
1460	 * the first fragment
1461	 */
1462	if (headersize + transhdrlen > mtu)
1463		goto emsgsize;
1464
1465	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1466	    (sk->sk_protocol == IPPROTO_UDP ||
1467	     sk->sk_protocol == IPPROTO_ICMPV6 ||
1468	     sk->sk_protocol == IPPROTO_RAW)) {
1469		ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1470				sizeof(struct ipv6hdr));
1471		goto emsgsize;
1472	}
1473
1474	if (ip6_sk_ignore_df(sk))
1475		maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1476	else
1477		maxnonfragsize = mtu;
1478
1479	if (cork->length + length > maxnonfragsize - headersize) {
1480emsgsize:
1481		pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
1482		ipv6_local_error(sk, EMSGSIZE, fl6, pmtu);
1483		return -EMSGSIZE;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1484	}
1485
1486	/* CHECKSUM_PARTIAL only with no extension headers and when
1487	 * we are not going to fragment
1488	 */
1489	if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1490	    headersize == sizeof(struct ipv6hdr) &&
1491	    length <= mtu - headersize &&
1492	    (!(flags & MSG_MORE) || cork->gso_size) &&
1493	    rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1494		csummode = CHECKSUM_PARTIAL;
1495
1496	if ((flags & MSG_ZEROCOPY) && length) {
1497		struct msghdr *msg = from;
1498
1499		if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {
1500			if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))
1501				return -EINVAL;
1502
1503			/* Leave uarg NULL if can't zerocopy, callers should
1504			 * be able to handle it.
1505			 */
1506			if ((rt->dst.dev->features & NETIF_F_SG) &&
1507			    csummode == CHECKSUM_PARTIAL) {
1508				paged = true;
1509				zc = true;
1510				uarg = msg->msg_ubuf;
1511			}
1512		} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
1513			uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
1514			if (!uarg)
1515				return -ENOBUFS;
1516			extra_uref = !skb_zcopy(skb);	/* only ref on new uarg */
1517			if (rt->dst.dev->features & NETIF_F_SG &&
1518			    csummode == CHECKSUM_PARTIAL) {
1519				paged = true;
1520				zc = true;
1521			} else {
1522				uarg_to_msgzc(uarg)->zerocopy = 0;
1523				skb_zcopy_set(skb, uarg, &extra_uref);
1524			}
1525		}
1526	} else if ((flags & MSG_SPLICE_PAGES) && length) {
1527		if (inet_test_bit(HDRINCL, sk))
1528			return -EPERM;
1529		if (rt->dst.dev->features & NETIF_F_SG &&
1530		    getfrag == ip_generic_getfrag)
1531			/* We need an empty buffer to attach stuff to */
1532			paged = true;
1533		else
1534			flags &= ~MSG_SPLICE_PAGES;
1535	}
1536
1537	hold_tskey = cork->tx_flags & SKBTX_ANY_TSTAMP &&
1538		     READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID;
1539	if (hold_tskey)
1540		tskey = atomic_inc_return(&sk->sk_tskey) - 1;
 
 
1541
1542	/*
1543	 * Let's try using as much space as possible.
1544	 * Use MTU if total length of the message fits into the MTU.
1545	 * Otherwise, we need to reserve fragment header and
1546	 * fragment alignment (= 8-15 octects, in total).
1547	 *
1548	 * Note that we may need to "move" the data from the tail
1549	 * of the buffer to the new fragment when we split
1550	 * the message.
1551	 *
1552	 * FIXME: It may be fragmented into multiple chunks
1553	 *        at once if non-fragmentable extension headers
1554	 *        are too large.
1555	 * --yoshfuji
1556	 */
1557
1558	cork->length += length;
1559	if (!skb)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1560		goto alloc_new_skb;
1561
1562	while (length > 0) {
1563		/* Check if the remaining data fits into current packet. */
1564		copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len;
1565		if (copy < length)
1566			copy = maxfraglen - skb->len;
1567
1568		if (copy <= 0) {
1569			char *data;
1570			unsigned int datalen;
1571			unsigned int fraglen;
1572			unsigned int fraggap;
1573			unsigned int alloclen, alloc_extra;
1574			unsigned int pagedlen;
1575alloc_new_skb:
1576			/* There's no room in the current skb */
1577			if (skb)
1578				fraggap = skb->len - maxfraglen;
1579			else
1580				fraggap = 0;
1581			/* update mtu and maxfraglen if necessary */
1582			if (!skb || !skb_prev)
1583				ip6_append_data_mtu(&mtu, &maxfraglen,
1584						    fragheaderlen, skb, rt,
1585						    orig_mtu);
1586
1587			skb_prev = skb;
1588
1589			/*
1590			 * If remaining data exceeds the mtu,
1591			 * we know we need more fragment(s).
1592			 */
1593			datalen = length + fraggap;
1594
1595			if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen)
1596				datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1597			fraglen = datalen + fragheaderlen;
1598			pagedlen = 0;
1599
1600			alloc_extra = hh_len;
1601			alloc_extra += dst_exthdrlen;
1602			alloc_extra += rt->dst.trailer_len;
1603
1604			/* We just reserve space for fragment header.
1605			 * Note: this may be overallocation if the message
1606			 * (without MSG_MORE) fits into the MTU.
1607			 */
1608			alloc_extra += sizeof(struct frag_hdr);
1609
1610			if ((flags & MSG_MORE) &&
1611			    !(rt->dst.dev->features&NETIF_F_SG))
1612				alloclen = mtu;
1613			else if (!paged &&
1614				 (fraglen + alloc_extra < SKB_MAX_ALLOC ||
1615				  !(rt->dst.dev->features & NETIF_F_SG)))
1616				alloclen = fraglen;
1617			else {
1618				alloclen = fragheaderlen + transhdrlen;
1619				pagedlen = datalen - transhdrlen;
1620			}
1621			alloclen += alloc_extra;
1622
1623			if (datalen != length + fraggap) {
1624				/*
1625				 * this is not the last fragment, the trailer
1626				 * space is regarded as data space.
1627				 */
1628				datalen += rt->dst.trailer_len;
1629			}
1630
 
1631			fraglen = datalen + fragheaderlen;
1632
1633			copy = datalen - transhdrlen - fraggap - pagedlen;
1634			/* [!] NOTE: copy may be negative if pagedlen>0
1635			 * because then the equation may reduces to -fraggap.
 
1636			 */
1637			if (copy < 0 && !(flags & MSG_SPLICE_PAGES)) {
1638				err = -EINVAL;
1639				goto error;
1640			}
1641			if (transhdrlen) {
1642				skb = sock_alloc_send_skb(sk, alloclen,
 
1643						(flags & MSG_DONTWAIT), &err);
1644			} else {
1645				skb = NULL;
1646				if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
1647				    2 * sk->sk_sndbuf)
1648					skb = alloc_skb(alloclen,
1649							sk->sk_allocation);
1650				if (unlikely(!skb))
 
1651					err = -ENOBUFS;
 
 
 
 
 
 
1652			}
1653			if (!skb)
1654				goto error;
1655			/*
1656			 *	Fill in the control structures
1657			 */
1658			skb->protocol = htons(ETH_P_IPV6);
1659			skb->ip_summed = csummode;
1660			skb->csum = 0;
1661			/* reserve for fragmentation and ipsec header */
1662			skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1663				    dst_exthdrlen);
1664
 
 
 
1665			/*
1666			 *	Find where to start putting bytes
1667			 */
1668			data = skb_put(skb, fraglen - pagedlen);
1669			skb_set_network_header(skb, exthdrlen);
1670			data += fragheaderlen;
1671			skb->transport_header = (skb->network_header +
1672						 fragheaderlen);
1673			if (fraggap) {
1674				skb->csum = skb_copy_and_csum_bits(
1675					skb_prev, maxfraglen,
1676					data + transhdrlen, fraggap);
1677				skb_prev->csum = csum_sub(skb_prev->csum,
1678							  skb->csum);
1679				data += fraggap;
1680				pskb_trim_unique(skb_prev, maxfraglen);
1681			}
1682			if (copy > 0 &&
1683			    getfrag(from, data + transhdrlen, offset,
1684				    copy, fraggap, skb) < 0) {
 
 
 
 
1685				err = -EFAULT;
1686				kfree_skb(skb);
1687				goto error;
1688			} else if (flags & MSG_SPLICE_PAGES) {
1689				copy = 0;
1690			}
1691
1692			offset += copy;
1693			length -= copy + transhdrlen;
1694			transhdrlen = 0;
1695			exthdrlen = 0;
1696			dst_exthdrlen = 0;
1697
1698			/* Only the initial fragment is time stamped */
1699			skb_shinfo(skb)->tx_flags = cork->tx_flags;
1700			cork->tx_flags = 0;
1701			skb_shinfo(skb)->tskey = tskey;
1702			tskey = 0;
1703			skb_zcopy_set(skb, uarg, &extra_uref);
1704
1705			if ((flags & MSG_CONFIRM) && !skb_prev)
1706				skb_set_dst_pending_confirm(skb, 1);
1707
1708			/*
1709			 * Put the packet on the pending queue
1710			 */
1711			if (!skb->destructor) {
1712				skb->destructor = sock_wfree;
1713				skb->sk = sk;
1714				wmem_alloc_delta += skb->truesize;
1715			}
1716			__skb_queue_tail(queue, skb);
1717			continue;
1718		}
1719
1720		if (copy > length)
1721			copy = length;
1722
1723		if (!(rt->dst.dev->features&NETIF_F_SG) &&
1724		    skb_tailroom(skb) >= copy) {
1725			unsigned int off;
1726
1727			off = skb->len;
1728			if (getfrag(from, skb_put(skb, copy),
1729						offset, copy, off, skb) < 0) {
1730				__skb_trim(skb, off);
1731				err = -EFAULT;
1732				goto error;
1733			}
1734		} else if (flags & MSG_SPLICE_PAGES) {
1735			struct msghdr *msg = from;
1736
1737			err = -EIO;
1738			if (WARN_ON_ONCE(copy > msg->msg_iter.count))
1739				goto error;
1740
1741			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
1742						   sk->sk_allocation);
1743			if (err < 0)
1744				goto error;
1745			copy = err;
1746			wmem_alloc_delta += copy;
1747		} else if (!zc) {
1748			int i = skb_shinfo(skb)->nr_frags;
1749
1750			err = -ENOMEM;
1751			if (!sk_page_frag_refill(sk, pfrag))
1752				goto error;
1753
1754			skb_zcopy_downgrade_managed(skb);
1755			if (!skb_can_coalesce(skb, i, pfrag->page,
1756					      pfrag->offset)) {
1757				err = -EMSGSIZE;
1758				if (i == MAX_SKB_FRAGS)
 
 
 
 
 
 
 
 
 
 
 
 
 
1759					goto error;
 
 
 
1760
1761				__skb_fill_page_desc(skb, i, pfrag->page,
1762						     pfrag->offset, 0);
1763				skb_shinfo(skb)->nr_frags = ++i;
1764				get_page(pfrag->page);
 
1765			}
1766			copy = min_t(int, copy, pfrag->size - pfrag->offset);
1767			if (getfrag(from,
1768				    page_address(pfrag->page) + pfrag->offset,
1769				    offset, copy, skb->len, skb) < 0)
1770				goto error_efault;
1771
1772			pfrag->offset += copy;
1773			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 
1774			skb->len += copy;
1775			skb->data_len += copy;
1776			skb->truesize += copy;
1777			wmem_alloc_delta += copy;
1778		} else {
1779			err = skb_zerocopy_iter_dgram(skb, from, copy);
1780			if (err < 0)
1781				goto error;
1782		}
1783		offset += copy;
1784		length -= copy;
1785	}
1786
1787	if (wmem_alloc_delta)
1788		refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1789	return 0;
1790
1791error_efault:
1792	err = -EFAULT;
1793error:
1794	net_zcopy_put_abort(uarg, extra_uref);
1795	cork->length -= length;
1796	IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1797	refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1798	if (hold_tskey)
1799		atomic_dec(&sk->sk_tskey);
1800	return err;
1801}
1802
1803int ip6_append_data(struct sock *sk,
1804		    int getfrag(void *from, char *to, int offset, int len,
1805				int odd, struct sk_buff *skb),
1806		    void *from, size_t length, int transhdrlen,
1807		    struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1808		    struct rt6_info *rt, unsigned int flags)
1809{
1810	struct inet_sock *inet = inet_sk(sk);
1811	struct ipv6_pinfo *np = inet6_sk(sk);
1812	int exthdrlen;
1813	int err;
1814
1815	if (flags&MSG_PROBE)
1816		return 0;
1817	if (skb_queue_empty(&sk->sk_write_queue)) {
1818		/*
1819		 * setup for corking
1820		 */
1821		dst_hold(&rt->dst);
1822		err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1823				     ipc6, rt);
1824		if (err)
1825			return err;
1826
1827		inet->cork.fl.u.ip6 = *fl6;
1828		exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1829		length += exthdrlen;
1830		transhdrlen += exthdrlen;
1831	} else {
1832		transhdrlen = 0;
1833	}
1834
1835	return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,
1836				 &np->cork, sk_page_frag(sk), getfrag,
1837				 from, length, transhdrlen, flags, ipc6);
1838}
1839EXPORT_SYMBOL_GPL(ip6_append_data);
1840
1841static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork)
1842{
1843	struct dst_entry *dst = cork->base.dst;
1844
1845	cork->base.dst = NULL;
1846	skb_dst_set(skb, dst);
1847}
1848
1849static void ip6_cork_release(struct inet_cork_full *cork,
1850			     struct inet6_cork *v6_cork)
1851{
1852	if (v6_cork->opt) {
1853		struct ipv6_txoptions *opt = v6_cork->opt;
1854
1855		kfree(opt->dst0opt);
1856		kfree(opt->dst1opt);
1857		kfree(opt->hopopt);
1858		kfree(opt->srcrt);
1859		kfree(opt);
1860		v6_cork->opt = NULL;
1861	}
1862
1863	if (cork->base.dst) {
1864		dst_release(cork->base.dst);
1865		cork->base.dst = NULL;
1866	}
 
1867}
1868
1869struct sk_buff *__ip6_make_skb(struct sock *sk,
1870			       struct sk_buff_head *queue,
1871			       struct inet_cork_full *cork,
1872			       struct inet6_cork *v6_cork)
1873{
1874	struct sk_buff *skb, *tmp_skb;
1875	struct sk_buff **tail_skb;
1876	struct in6_addr *final_dst;
 
 
1877	struct net *net = sock_net(sk);
1878	struct ipv6hdr *hdr;
1879	struct ipv6_txoptions *opt = v6_cork->opt;
1880	struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1881	struct flowi6 *fl6 = &cork->fl.u.ip6;
1882	unsigned char proto = fl6->flowi6_proto;
 
1883
1884	skb = __skb_dequeue(queue);
1885	if (!skb)
1886		goto out;
1887	tail_skb = &(skb_shinfo(skb)->frag_list);
1888
1889	/* move skb->data to ip header from ext header */
1890	if (skb->data < skb_network_header(skb))
1891		__skb_pull(skb, skb_network_offset(skb));
1892	while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1893		__skb_pull(tmp_skb, skb_network_header_len(skb));
1894		*tail_skb = tmp_skb;
1895		tail_skb = &(tmp_skb->next);
1896		skb->len += tmp_skb->len;
1897		skb->data_len += tmp_skb->len;
1898		skb->truesize += tmp_skb->truesize;
1899		tmp_skb->destructor = NULL;
1900		tmp_skb->sk = NULL;
1901	}
1902
1903	/* Allow local fragmentation. */
1904	skb->ignore_df = ip6_sk_ignore_df(sk);
1905	__skb_pull(skb, skb_network_header_len(skb));
1906
1907	final_dst = &fl6->daddr;
 
1908	if (opt && opt->opt_flen)
1909		ipv6_push_frag_opts(skb, opt, &proto);
1910	if (opt && opt->opt_nflen)
1911		ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1912
1913	skb_push(skb, sizeof(struct ipv6hdr));
1914	skb_reset_network_header(skb);
1915	hdr = ipv6_hdr(skb);
1916
1917	ip6_flow_hdr(hdr, v6_cork->tclass,
1918		     ip6_make_flowlabel(net, skb, fl6->flowlabel,
1919					ip6_autoflowlabel(net, sk), fl6));
1920	hdr->hop_limit = v6_cork->hop_limit;
1921	hdr->nexthdr = proto;
1922	hdr->saddr = fl6->saddr;
1923	hdr->daddr = *final_dst;
1924
1925	skb->priority = READ_ONCE(sk->sk_priority);
1926	skb->mark = cork->base.mark;
1927	skb->tstamp = cork->base.transmit_time;
1928
1929	ip6_cork_steal_dst(skb, cork);
1930	IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
1931	if (proto == IPPROTO_ICMPV6) {
1932		struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1933		u8 icmp6_type;
1934
1935		if (sk->sk_socket->type == SOCK_RAW &&
1936		   !inet_test_bit(HDRINCL, sk))
1937			icmp6_type = fl6->fl6_icmp_type;
1938		else
1939			icmp6_type = icmp6_hdr(skb)->icmp6_type;
1940		ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type);
1941		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1942	}
1943
1944	ip6_cork_release(cork, v6_cork);
1945out:
1946	return skb;
1947}
1948
1949int ip6_send_skb(struct sk_buff *skb)
1950{
1951	struct net *net = sock_net(skb->sk);
1952	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1953	int err;
1954
1955	err = ip6_local_out(net, skb->sk, skb);
1956	if (err) {
1957		if (err > 0)
1958			err = net_xmit_errno(err);
1959		if (err)
1960			IP6_INC_STATS(net, rt->rt6i_idev,
1961				      IPSTATS_MIB_OUTDISCARDS);
1962	}
1963
 
 
1964	return err;
1965}
1966
1967int ip6_push_pending_frames(struct sock *sk)
1968{
1969	struct sk_buff *skb;
1970
1971	skb = ip6_finish_skb(sk);
1972	if (!skb)
1973		return 0;
1974
1975	return ip6_send_skb(skb);
1976}
1977EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1978
1979static void __ip6_flush_pending_frames(struct sock *sk,
1980				       struct sk_buff_head *queue,
1981				       struct inet_cork_full *cork,
1982				       struct inet6_cork *v6_cork)
1983{
1984	struct sk_buff *skb;
1985
1986	while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1987		if (skb_dst(skb))
1988			IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1989				      IPSTATS_MIB_OUTDISCARDS);
1990		kfree_skb(skb);
1991	}
1992
1993	ip6_cork_release(cork, v6_cork);
1994}
1995
1996void ip6_flush_pending_frames(struct sock *sk)
1997{
1998	__ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1999				   &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
2000}
2001EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
2002
2003struct sk_buff *ip6_make_skb(struct sock *sk,
2004			     int getfrag(void *from, char *to, int offset,
2005					 int len, int odd, struct sk_buff *skb),
2006			     void *from, size_t length, int transhdrlen,
2007			     struct ipcm6_cookie *ipc6, struct rt6_info *rt,
2008			     unsigned int flags, struct inet_cork_full *cork)
2009{
2010	struct inet6_cork v6_cork;
2011	struct sk_buff_head queue;
2012	int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
2013	int err;
2014
2015	if (flags & MSG_PROBE) {
2016		dst_release(&rt->dst);
2017		return NULL;
2018	}
2019
2020	__skb_queue_head_init(&queue);
2021
2022	cork->base.flags = 0;
2023	cork->base.addr = 0;
2024	cork->base.opt = NULL;
2025	v6_cork.opt = NULL;
2026	err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt);
2027	if (err) {
2028		ip6_cork_release(cork, &v6_cork);
2029		return ERR_PTR(err);
2030	}
2031	if (ipc6->dontfrag < 0)
2032		ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk);
2033
2034	err = __ip6_append_data(sk, &queue, cork, &v6_cork,
2035				&current->task_frag, getfrag, from,
2036				length + exthdrlen, transhdrlen + exthdrlen,
2037				flags, ipc6);
2038	if (err) {
2039		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
2040		return ERR_PTR(err);
2041	}
2042
2043	return __ip6_make_skb(sk, &queue, cork, &v6_cork);
2044}